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Different Functions (different + function)
Selected AbstractsSignificance of processes in the near-stream zone on stream water acidity in a small acidified forested catchmentHYDROLOGICAL PROCESSES, Issue 2 2001Jens Fölster Abstract The near-stream zone has received increasing attention owing to its influence on stream water chemistry in general and acidity in particular. Possible processes in this zone include cation exchange, leaching of organic matter and redox reactions of sulphur compounds. In this study the influences of processes in the near-stream zone on the acidity in runoff from a small, acidified catchment in central southern Sweden were investigated. The study included sampling of groundwater, soil water and stream water along with hydrological measurements. An input,output budget for the catchment was established based on data from the International Co-operative Programme on Integrated Monitoring at this site. The catchment was heavily acidified by deposition of anthropogenic sulphur, with pH in stream water between 4·4 and 4·6. There was also no relationship between stream flow and pH, which is indicative of chronic acidification. Indications of microbial reduction of sulphate were found in some places near the stream, but the near-stream zone did not have a general impact on the sulphate concentration in discharging groundwater. The near-stream zone was a source of dissolved organic carbon (DOC) in the stream, which had a median DOC of 6·8 mg L1. The influence on stream acidity from organic anions was overshadowed by the effect of sulphate, however, except during a spring flow episode, when additional organic matter was flushed out and the sulphate-rich ground water was mixed with more diluted event water. Ion exchange was not an important process in the near-stream zone of the Kindla catchment. Different functions of the near-stream zone relating to discharge acidity are reported in the literature. In this study there was even a variation within the site. There is therefore a need for more case studies to provide a more detailed understanding of the net effects that the near-stream zone can have on stream chemistry under different circumstances. Copyright © 2001 John Wiley & Sons, Ltd. [source] Human platelets express hemochromatosis protein (HFE) and transferrin receptor 2EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2003Jokke Hannuksela Abstract: Objectives: While body iron status may influence platelets, little information is available about platelet expression of proteins regulating iron homeostasis. HFE, the protein defective in hereditary hemochromatosis, and transferrin receptor 2 (TfR2) are two novel protein candidates that could be involved in mechanisms of iron transport across the platelet plasma membrane. Methods: The expression and localization of HFE, TfR1 and TfR2 proteins in human platelets were examined using Western blotting and immunocytochemistry. Results: Human platelets expressed HFE and TfR2, whereas no signal for TfR1 was found. The positive reactions for HFE and TfR2 were mainly confined to the platelet plasma membrane. Conclusions: Expression of HFE and TfR2 proteins in human platelets may indicate that the mutations in the corresponding genes could influence platelet count, size and/or activation. The presence of TfR2 and absence of TfR1 suggests that HFE may serve a different function in platelets compared with the other HFE-positive cell types, e.g. enterocytes, macrophages and syncytiotrophoblasts. [source] Laminin-5 stimulates hepatocellular carcinoma growth through a different function of ,6,4 and ,3,1 integrins,HEPATOLOGY, Issue 6 2007Carlo Bergamini Hepatocellular carcinoma (HCC) growth severely affects prognosis. Ki-67, a known marker of cell proliferation, is a negative prognostic factor in HCC. Growth factors such as the epidermal growth factor (EGF) induce HCC cell proliferation but do not explain the great heterogeneity of HCC growth. Laminin-5 (Ln-5) is an extracellular matrix protein (ECM) present in the tissue microenvironment of HCC. The two main receptors for Ln-5, integrins ,3,1 and ,6,4, are expressed on the cell surface of HCC cells. The aim of this study is to investigate an alternative mechanism of HCC growth whereby Ln-5 promotes HCC cell proliferation through ,3,1 and ,6,4. HCC tissues containing Ln-5 display a larger diameter and higher number of positive cells for Ki-67, a well known proliferative index, as determined by double immunofluorescence staining and real-time PCR on microdissected tissues. In vitro, Ln-5, but not collagen I, collagen IV or fibronectin, induces proliferation as much as EGF does, via Erk phosphorylation as a consequence of ,4 integrin phosphorylation. However, the two HCC cell lines do not proliferate in presence of Ln-5 despite ,4 integrin and Erk1/2 activation. After transfection with ,3 integrin, in the presence of Ln-5 one of these HCC cell lines acquires a proliferative activity whereas one of the proliferative HCC cell lines, knocked-down for ,3 integrin, loses its proliferative activity. Conclusions: Our study suggests a new mechanism of HCC growth whereby Ln-5 stimulates proliferation via a different function of ,6,4 and ,3,1. (HEPATOLOGY 2007.) [source] Intra- and intermuscular variation in human quadriceps femoris architecture assessed in vivoJOURNAL OF ANATOMY, Issue 3 2006Anthony J. Blazevich Abstract Despite the functional importance of the human quadriceps femoris in movements such as running, jumping, lifting and climbing, and the known effects of muscle architecture on muscle function, no research has fully described the complex architecture of this muscle group. We used ultrasound imaging techniques to measure muscle thickness, fascicle angle and fascicle length at multiple regions of the four quadriceps muscles in vivo in 31 recreationally active, but non-strength-trained adult men and women. Our analyses revealed a reasonable similarity in the superficial quadriceps muscles, which is suggestive of functional similarity (at least during the uni-joint knee extension task) given that they act via a common tendon. The deep vastus intermedius (VI) is architecturally dissimilar and therefore probably serves a different function(s). Architecture varies significantly along the length of the superficial muscles, which has implications for the accuracy of models that assume a constant intramuscular architecture. It might also have consequences for the efficiency of intra- and intermuscular force transmission. Our results provide some evidence that subjects with a given architecture of one superficial muscle, relative to the rest of the subject sample, also have a similar architecture in other superficial muscles. However, this is not necessarily true for vastus lateralis (VL), and was not the case for VI. Therefore, the relative architecture of one muscle cannot confidently be used to estimate the relative architecture of another. To confirm this, we calculated a value of whole quadriceps architecture by four different methods. Regardless of the method used, we found that the absolute or relative architecture of one muscle could not be used as an indicator of whole quadriceps architecture, although vastus medialis, possibly in concert with VL and the anterior portion of VI, could be used to provide a useful snapshot. Importantly, our estimates of whole quadriceps architecture show a gender difference in whole quadriceps muscle thickness, and that muscle thickness is positively correlated with fascicle angle whereas fascicle length is negatively, although weakly, correlated with fascicle angle. These results are supportive of the validity of estimates of whole quadriceps architecture. These data are interpreted with respect to their implications for neural control strategies, region-specific adaptations in muscle size in response to training, and gender-dependent differences in the response to exercise training. [source] Rat Spag5 associates in somatic cells with endoplasmic reticulum and microtubules but in spermatozoa with outer dense fibersMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2006Carolyn J. Fitzgerald Abstract The leucine zipper motif has been identified as an important and specific interaction motif used by various sperm tail proteins that localize to the outer dense fibers. We had found that rat Odf1, a major integral ODF protein, utilizes its leucine zipper to associate with Odf2, another major ODF protein, Spag4 which localizes to the interface between ODF and axonemal microtubule doublets, and Spag5. The rat Spag5 sequence indicated a close relationship with human Astrin, a microtubule-binding spindle protein suggesting that Spag5, like Spag4, may associate with the sperm tail axoneme. RT PCR assays indicated expression of Spag5 in various tissues and in somatic cells Spag5 localizes to endoplasmic reticulum and microtubules, as expected for an Astrin orthologue. MT binding was confirmed both in vivo and in in vitro MT-binding assays: somatic cells contain a 58 kDa MT-associated Spag5 protein. Western blotting assays of rat somatic cells and male germ cells at different stages of development using anti-Spag5 antibodies demonstrated that the protein expression pattern changes during spermatogenesis and that sperm tails contain a 58 kDa Spag5 protein. Use of affinity-purified anti-Spag5 antibodies in immuno electron microscopy shows that in rat elongated spermatids and epididymal sperm the Spag5 protein associates with ODF, but not with the axonemal MTs. This observation is in contrast to that for the other Odf1-binding, MT-binding protein Spag4, which is present between ODF and axoneme. Our data demonstrate that Spag5 has different localization in somatic versus male germ cells suggesting the possibility of different function. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source] REVIEW ARTICLE: Evolution and Function of the Uterine Serpins (SERPINA14)AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2010Maria B. Padua Citation Padua MB, Hansen PJ. Evolution and function of the uterine serpins (SERPINA14). Am J Reprod Immunol 2010 Uterine serpins (recently designated as SERPINA14) are hormonally induced proteins secreted in large quantities by the endometrial epithelium during pregnancy. The SERPINA14 proteins belong to the serine proteinase inhibitor (serpin) superfamily, but their apparent lack of inhibitory activity toward serine proteinases suggests that these proteins evolved a different function from the anti-proteinase activity typically found in most members of the serpin superfamily. The gene is present in a limited group of mammals in the Laurasiatheria superorder (ruminants, horses, pigs, dolphins and some carnivores) while being absent in primates, rodents, lagomorphs and marsupials. Thus, the gene is likely to have evolved by gene duplication after divergence of Laurasiatheria and to play an important role in pregnancy. That role may vary between species. In sheep, SERPINA14 probably serves an immunoregulatory role to prevent rejection of the fetal allograft. It is inhibitory to lymphocyte proliferation and natural killer cell function. In the pig, SERPINA14 is involved in iron transport to the fetus by binding to and stabilizing the iron-binding protein uteroferrin. It is possible that SERPINA14 has undergone divergence in function since the original emergence of the gene in a common ancestor of species possessing SERPINA14. [source] Receptive fields and functional architecture in the retinaTHE JOURNAL OF PHYSIOLOGY, Issue 12 2009Vijay Balasubramanian Functional architecture of the striate cortex is known mostly at the tissue level , how neurons of different function distribute across its depth and surface on a scale of millimetres. But explanations for its design , why it is just so , need to be addressed at the synaptic level, a much finer scale where the basic description is still lacking. Functional architecture of the retina is known from the scale of millimetres down to nanometres, so we have sought explanations for various aspects of its design. Here we review several aspects of the retina's functional architecture and find that all seem governed by a single principle: represent the most information for the least cost in space and energy. Specifically: (i) why are OFF ganglion cells more numerous than ON cells? Because natural scenes contain more negative than positive contrasts, and the retina matches its neural resources to represent them equally well; (ii) why do ganglion cells of a given type overlap their dendrites to achieve 3-fold coverage? Because this maximizes total information represented by the array , balancing signal-to-noise improvement against increased redundancy; (iii) why do ganglion cells form multiple arrays? Because this allows most information to be sent at lower rates, decreasing the space and energy costs for sending a given amount of information. This broad principle, operating at higher levels, probably contributes to the brain's immense computational efficiency. [source] The evolutionary psychology of left and right: Costs and benefits of lateralizationDEVELOPMENTAL PSYCHOBIOLOGY, Issue 6 2006Giorgio VallortigaraArticle first published online: 2 AUG 200 Abstract Why do the left and right sides of the vertebrate brain play different functions? Having a lateralized brain, in which each hemisphere carries out different functions, is ubiquitous among vertebrates. The different specialization of the left and right side of the brain may increase brain efficiency,and some evidence for that is reported here. However, lateral biases due to brain lateralization (such as preferences in the use of a limb or, in animals with laterally placed eyes, of a visual hemifield) usually occur at the population level, with most individuals showing similar direction of bias. Individual brain efficiency does not require the alignment of lateralization in the population. Why then are not left- and right-type individuals equally common? Not only humans, but most vertebrates show a similar pattern. For instance, in the paper I report evidence that most toads, chickens, and fish react faster when a predator approaches from the left. I argue that invoking individual brain efficiency (lateralization may increase fitness), evolutionary chance or direct genetic mechanisms cannot explain this widespread pattern. Instead, using concepts from mathematical theory of games, I show that alignment of lateralization at the population level may arise as an "evolutionarily stable strategy" when individually asymmetrical organisms must coordinate their behavior with that of other asymmetrical organisms. Thus, the population structure of lateralization may result from genes specifying the direction of asymmetries which have been selected under "social" pressures. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 418,427, 2006. [source] Acetyl-CoA carboxylases 1 and 2 show distinct expression patterns in rats and humans and alterations in obesity and diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2009Sebastian Kreuz Abstract Background Acetyl-CoA carboxylases (ACC) 1 and 2 are central enzymes in lipid metabolism. To further investigate their relevance for the development of obesity and type 2 diabetes, expression of both ACC isoforms was analyzed in obese fa/fa Zucker fatty and Zucker diabetic fatty rats at different ages in comparison to Zucker lean controls. Methods ACC1 and ACC2 transcript levels were measured by quantitative real-time polymerase chain reaction in metabolically relevant tissues of Zucker fatty, Zucker diabetic fatty and Zucker lean control animals. Quantitative real-time polymerase chain reaction was also applied to measure ACC tissue distribution in human tissues. For confirmation on a protein level, quantitative mass spectrometry was used. Results Disease-related transcriptional changes of both ACC isoforms were observed in various tissues of Zucker fatty and Zucker diabetic fatty rats including liver, pancreas and muscle. Changes were most prominent in oxidative tissues of diabetic rats, where ACC2 was significantly increased and ACC1 was reduced compared with Zucker lean control animals. A comparison of the overall tissue distribution of both ACC isoforms in humans and rats surprisingly revealed strong differences. While in rats ACC1 was mainly expressed in lipogenic and ACC2 in oxidative tissues, ACC2 was predominant in oxidative and lipogenic tissues in humans. Conclusion Our data support a potential role for both ACC isoforms in the development of obesity and diabetes in rats. However, the finding of fundamental species differences in ACC1 and ACC2 tissue expression might be indicative for different functions of both isoforms in humans and rats and raises the question to which degree these models are predictive for the physiology and pathophysiology of lipid metabolism in humans. Copyright © 2009 John Wiley & Sons, Ltd. [source] The Many Facets of Identity CriteriaDIALECTICA, Issue 2 2004Massimiliano Carrara The aim of this note is to discuss the general form and role of identity criteria. We have taken two readings into consideration which express two different functions of identity criteria. The first expresses the epistemic function whilst the second deals with the ontological function. We argue that there are several problems related to the specification of both these functions. As a consequence, we conclude that identity criteria are not necessary to provide ontological legitimacy. [source] Avoiding tragedies: a Flemish common and its commoners under the pressure of social and economic change during the eighteenth century1ECONOMIC HISTORY REVIEW, Issue 1 2009TINE DE MOOR Despite the wide application of the metaphor of ,the tragedy of the commons', there is little historical literature that points to the weaknesses of its historical basis. There is, however, sufficient qualitative and quantitative evidence to prove that commons were well regulated and organized in order to achieve a sustainable management, that also took into account the needs and wishes of its commoners. This case study of a common in Flanders looks at the evidence for this in the eighteenth century, examining bookkeeping and other archival sources. A model that incorporates the different functions of the commons (sustainability, efficiency, and utility) is explained and applied. [source] Architecture of developing multicellular yeast colony: spatio-temporal expression of Ato1p ammonium exporterENVIRONMENTAL MICROBIOLOGY, Issue 7 2009e Váchová Summary Yeasts, when growing on solid surfaces, form organized multicellular structures, colonies, in which cells differentiate and thus possess different functions and undergo dissimilar fate. Understanding the principles involved in the formation of these structures requires new approaches that allow the study of individual cells directly in situ without needing to remove them from the microbial community. Here we introduced a new approach to the analysis of whole yeast microcolonies either containing specific proteins labelled by fluorescent proteins or stained with specific dyes, by two-photon excitation confocal microscopy. It revealed that the colonies are covered with a thin protective skin-like surface cell layer which blocks penetration of harmful compounds. The cells forming the layer are tightly connected via cell walls, the presence of which is essential for keeping of protective layer function. Viewing the colonies from different angles allowed us to reconstruct a three-dimensional profile of the cells producing ammonium exporter Ato1p within developing microcolonies growing either as individuals or within a group of microcolonies. We show that neighbouring microcolonies coordinate production of Ato1p-GFP. Ato1p itself appears synchronously in cells, which do not originate from the same ancestor, but occupy specific position within the colony. [source] Differential routing of coexisting neuropeptides in vasopressin neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2003Marc Landry Abstract The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis. The various populations of labelled granules were quantitatively compared in three subcellular compartments: perikarya, local processes and posthypophyseal nerve endings. Three subpopulations of granules were detected in all three compartments, but their respective amount showed significant differences. Galanin alone was immunolocalized in some secretory granules, vasopressin alone in others, and both peptides in a third subpopulation of granules. The major part of the granules containing vasopressin, either alone or in association with galanin, is found in neurohypophyseal nerve endings. In contrast, galanin single-labelled granules represent the most abundant population in dendritic processes, while double-labelled granules are more numerous in perikarya. This indicates a preferential distribution of the two peptides in the different compartments of magnocellular neurons. Furthermore, galanin and vasopressin messenger RNAs were detected at different domains of the endoplasmic reticulum, suggesting that translation might also occur at different locations, thus leading to partial segregation of galanin and vasopressin cargoes between two populations of secretory granules. The present study provides, for the first time in mammals, evidence suggesting that galanin and vasopressin are only partly copackaged and undergo a preferential targeting toward dendrites or neurohypophysis, suggesting different functions, autocrine/paracrine and endocrine, respectively. [source] Differential routing of coexisting neuropeptides in vasopressin neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Marc Landry Abstract The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis. The various populations of labelled granules were quantitatively compared in three subcellular compartments: perikarya, local processes and posthypophyseal nerve endings. Three subpopulations of granules were detected in all three compartments, but their respective amount showed significant differences. Galanin alone was immunolocalized in some secretory granules, vasopressin alone in others, and both peptides in a third subpopulation of granules. The major part of the granules containing vasopressin, either alone or in association with galanin, is found in neurohypophyseal nerve endings. In contrast, galanin single-labelled granules represent the most abundant population in dendritic processes, while double-labelled granules are more numerous in perikarya. This indicates a preferential distribution of the two peptides in the different compartments of magnocellular neurons. Furthermore, galanin and vasopressin messenger RNAs were detected at different domains of the endoplasmic reticulum, suggesting that translation might also occur at different locations, thus leading to partial segregation of galanin and vasopressin cargoes between two populations of secretory granules. The present study provides, for the first time in mammals, evidence suggesting that galanin and vasopressin are only partly copackaged and undergo a preferential targeting toward dendrites or neurohypophysis, suggesting different functions, autocrine/paracrine and endocrine, respectively. [source] Discussion on ,Personality psychology as a truly behavioural science' by R. Michael FurrEUROPEAN JOURNAL OF PERSONALITY, Issue 5 2009Article first published online: 14 JUL 200 Yes We Can! A Plea for Direct Behavioural Observation in Personality Research MITJA D. BACK and BORIS EGLOFF Department of Psychology, Johannes Gutenberg University Mainz, Germany mback@uni-leipzig.de Furr's target paper (this issue) is thought to enhance the standing of personality psychology as a truly behavioural science. We wholeheartedly agree with this goal. In our comment we argue for more specific and ambitious requirements for behavioural personality research. Specifically, we show why behaviour should be observed directly. Moreover, we illustratively describe potentially interesting approaches in behavioural personality research: lens model analyses, the observation of multiple behaviours in diverse experimentally created situations and the observation of behaviour in real life. Copyright © 2009 John Wiley & Sons, Ltd. The Categories of Behaviour Should be Clearly Defined PETER BORKENAU Department of Psychology, Martin-Luther University Halle-Wittenberg, Germany p.borkenau@psych.uni-halle.de The target paper is helpful by clarifying the terminology as well as the strengths and weaknesses of several approaches to collect behavioural data. Insufficiently considered, however, is the clarity of the categories being used for the coding of behaviour. Evidence is reported showing that interjudge agreement for retrospective and even concurrent codings of behaviour does not execeed interjudge agreement for personality traits if the categories being used for the coding of behaviour are not clearly defined. By contrast, if the behaviour to be registered is unambiguously defined, interjudge agreement may be almost perfect. Copyright © 2009 John Wiley & Sons, Ltd. Behaviour Functions in Personality Psychology PHILIP J. CORR Department of Psychology, Faculty of Social Sciences, University of East Anglia, Norwich, UK Philip.Corr@btopenworld.com Furr's target paper highlights the importance, yet under-representation, of behaviour in published articles in personality psychology. Whilst agreeing with most of his points, I remain unclear as to how behaviour (as specifically defined by Furr) relates to other forms of psychological data (e.g. cognitive task performance). In addition, it is not clear how the functions of behaviour are to be decided: different behaviours may serve the same function; and identical behaviours may serve different functions. To clarify these points, methodological and theoretical aspects of Furr's proposal would benefit from delineation. Copyright © 2009 John Wiley & Sons, Ltd. On the Difference Between Experience-Sampling Self-Reports and Other Self-Reports WILLIAM FLEESON Department of Psychology, Wake Forest University, Winston-Salem, NC, USA fleesonW@wfu.edu Furr's fair but evaluative consideration of the strengths and weaknesses of behavioural assessment methods is a great service to the field. As part of his consideration, Furr makes a subtle and sophisticated distinction between different self-report methods. It is easy to dismiss all self-reports as poor measures, because some are poor. In contrast, Furr points out that the immediacy of the self-reports of behaviour in experience-sampling make experience-sampling one of the three strongest methods for assessing behaviour. This comment supports his conclusion, by arguing that ESM greatly diminishes one the three major problems afflicting self-reports,lack of knowledge,and because direct observations also suffer from the other two major problems afflicting self-reports. Copyright © 2009 John Wiley & Sons, Ltd. What and Where is ,Behaviour' in Personality Psychology? LAURA A. KING and JASON TRENT Department of Psychology, University of Missouri, Columbia, USA kingla@missouri.edu Furr is to be lauded for presenting a coherent and persuasive case for the lack of behavioural data in personality psychology. While agreeing wholeheartedly that personality psychology could benefit from greater inclusion of behavioural variables, here we question two aspects of Furr's analysis, first his definition of behaviour and second, his evidence that behaviour is under-appreciated in personality psychology. Copyright © 2009 John Wiley & Sons, Ltd. Naturalistic Observation of Daily Behaviour in Personality Psychology MATTHIAS R. MEHL Department of Psychology, University of Arizona, Tucson, AZ, USA mehl@email.arizona.edu This comment highlights naturalistic observation as a specific method within Furr's (this issue) cluster direct behavioural observation and discusses the Electronically Activated Recorder (EAR) as a naturalistic observation sampling method that can be used in relatively large, nomothetic studies. Naturalistic observation with a method such as the EAR can inform researchers' understanding of personality in its relationship to daily behaviour in two important ways. It can help calibrate personality effects against act-frequencies of real-world behaviour and provide ecological, behavioural personality criteria that are independent of self-report. Copyright © 2009 John Wiley & Sons, Ltd. Measuring Behaviour D. S. MOSKOWITZ and JENNIFER J. RUSSELL Department of Psychology, McGill University, Montreal, Canada dsm@psych.mcgill.ca Furr (this issue) provides an illuminating comparison of the strengths and weaknesses of various methods for assessing behaviour. In the selection of a method for assessing behaviour, there should be a careful analysis of the definition of the behaviour and the purpose of assessment. This commentary clarifies and expands upon some points concerning the suitability of experience sampling measures, referred to as Intensive Repeated Measurements in Naturalistic Settings (IRM-NS). IRM-NS measures are particularly useful for constructing measures of differing levels of specificity or generality, for providing individual difference measures which can be associated with multiple layers of contextual variables, and for providing measures capable of reflecting variability and distributional features of behaviour. Copyright © 2009 John Wiley & Sons, Ltd. Behaviours, Non-Behaviours and Self-Reports SAMPO V. PAUNONEN Department of Psychology, University of Western Ontario, London, Canada paunonen@uwo.ca Furr's (this issue) thoughtful analysis of the contemporary body of research in personality psychology has led him to two conclusions: our science does not do enough to study real, observable behaviours; and, when it does, too often it relies on ,weak' methods based on retrospective self-reports of behaviour. In reply, I note that many researchers are interested in going beyond the study of individual behaviours to the behaviour trends embodied in personality traits; and the self-report of behaviour, using well-validated personality questionnaires, is often the best measurement option. Copyright © 2009 John Wiley & Sons, Ltd. An Ethological Perspective on How to Define and Study Behaviour LARS PENKE Department of Psychology, The University of Edinburgh, Edinburgh, UK lars.penke@ed.ac.uk While Furr (this issue) makes many important contributions to the study of behaviour, his definition of behaviour is somewhat questionable and also lacks a broader theoretical frame. I provide some historical and theoretical background on the study of behaviour in psychology and biology, from which I conclude that a general definition of behaviour might be out of reach. However, psychological research can gain from adding a functional perspective on behaviour in the tradition of Tinbergens's four questions, which takes long-term outcomes and fitness consequences of behaviours into account. Copyright © 2009 John Wiley & Sons, Ltd. What is a Behaviour? MARCO PERUGINI Faculty of Psychology, University of Milan,Bicocca, Milan, Italy marco.perugini@unimib.it The target paper proposes an interesting framework to classify behaviour as well as a convincing plea to use it more often in personality research. However, besides some potential issues in the definition of what is a behaviour, the application of the proposed definition to specific cases is at times inconsistent. I argue that this is because Furr attempts to provide a theory-free definition yet he implicitly uses theoretical considerations when applying the definition to specific cases. Copyright © 2009 John Wiley & Sons, Ltd. Is Personality Really the Study of Behaviour? MICHAEL D. ROBINSON Department of Psychology, North Dakota State University, Fargo, ND, USA Michael.D.Robinson@ndsu.edu Furr (this issue) contends that behavioural studies of personality are particularly important, have been under-appreciated, and should be privileged in the future. The present commentary instead suggests that personality psychology has more value as an integrative science rather than one that narrowly pursues a behavioural agenda. Cognition, emotion, motivation, the self-concept and the structure of personality are important topics regardless of their possible links to behaviour. Indeed, the ultimate goal of personality psychology is to understanding individual difference functioning broadly considered rather than behaviour narrowly considered. Copyright © 2009 John Wiley & Sons, Ltd. Linking Personality and Behaviour Based on Theory MANFRED SCHMITT Department of Psychology, University of Koblenz-Landau, Landau, Germany schmittm@uni-landau.de My comments on Furr's (this issue) target paper ,Personality as a Truly Behavioural Science' are meant to complement his behavioural taxonomy and sharpen some of the presumptions and conclusions of his analysis. First, I argue that the relevance of behaviour for our field depends on how we define personality. Second, I propose that every taxonomy of behaviour should be grounded in theory. The quality of behavioural data does not only depend on the validity of the measures we use. It also depends on how well behavioural data reflect theoretical assumptions on the causal factors and mechanisms that shape behaviour. Third, I suggest that the quality of personality theories, personality research and behavioural data will profit from ideas about the psychological processes and mechanisms that link personality and behaviour. Copyright © 2009 John Wiley & Sons, Ltd. The Apparent Objectivity of Behaviour is Illusory RYNE A. SHERMAN, CHRISTOPHER S. NAVE and DAVID C. FUNDER Department of Psychology, University of California, Riverside, CA, USA funder@ucr.edu It is often presumed that objective measures of behaviour (e.g. counts of the number of smiles) are more scientific than more subjective measures of behaviour (e.g. ratings of the degree to which a person behaved in a cheerful manner). We contend that the apparent objectivity of any behavioural measure is illusory. First, the reliability of more subjective measures of behaviour is often strikingly similar to the reliabilities of so-called objective measures. Further, a growing body of literature suggests that subjective measures of behaviour provide more valid measures of psychological constructs of interest. Copyright © 2009 John Wiley & Sons, Ltd. Personality and Behaviour: A Neglected Opportunity? LIAD UZIEL and ROY F. BAUMEISTER Department of Psychology, Florida State University, Tallahassee, FL, USA Baumeister@psy.fsu.edu Personality psychology has neglected the study of behaviour. Furr's efforts to provide a stricter definition of behaviour will not solve the problem, although they may be helpful in other ways. His articulation of various research strategies for studying behaviour will be more helpful for enabling personality psychology to contribute important insights and principles about behaviour. The neglect of behaviour may have roots in how personality psychologists define the mission of their field, but expanding that mission to encompass behaviour would be a positive step. Copyright © 2009 John Wiley & Sons, Ltd. [source] The expanding family of -RFamide peptides and their effects on feeding behaviourEXPERIMENTAL PHYSIOLOGY, Issue 3 2004Graham J. Dockray Neuropeptides terminating in -Arg-Phe-NH2 (-RFamide) were first discovered in molluscan nervous systems, but were soon recognized to occur widely throughout the invertebrates. Progress in characterizing members of the family in vertebrates has been slower. In mammals, however, it is now clear that there are at least five genes encoding members of the family, and at least five G-protein-coupled receptors at which they act. The tissue distribution of the peptides and their receptors is wide and there are likely to be many different functions. One of the emerging themes from recent research is that these peptides are involved in control of feeding behaviour both in invertebrates and in vertebrates. This would seem to be a remarkable example of conservation of chemical structure and biological function throughout nervous system evolution. [source] Structural disorder in amyloid fibrils: its implication in dynamic interactions of proteinsFEBS JOURNAL, Issue 19 2009P. Tompa Proteins are occasionally converted from their normal soluble state to highly ordered fibrillar aggregates (amyloids), which give rise to pathological conditions that range from neurodegenerative disorders to systemic amyloidoses. Recent methodological advances in solid-state NMR and EPR spectroscopy have enabled determination of the 3D structure of several amyloids at residue-level resolution. The general picture that emerges is that amyloids constitute parallel , sheets, in which individual polypeptide chains run roughly perpendicular to the major axis of the fibril and are stacked in-register. Thus, the unifying theme of amyloid formation is the structural transition from an initial globular or intrinsically disordered state to a highly ordered regular form. In this minireview, we show that this description is somewhat oversimplified, because part of the polypeptide chain in the amyloid remains intrinsically disordered and does not become part of the ordered core. As demonstrated through examples such as the amyloids of ,-synuclein and A, peptide and the yeast prions HET-s and Ure2p, these disordered segments are depleted in amino acids NQFYV and are enriched in DEKP. They are also significantly more charged and have a higher predicted disordered value than segments in the cross-, core. We suggest that structural disorder in amyloid is a special case of ,fuzziness', i.e. disorder in the bound state that may serve different functions, such as the accommodation of destabilizing residues and the mediation of secondary interactions between protofibrils. [source] Alanine screening of the intracellular loops of the human bradykinin B2 receptor , effects on receptor maintenance, G protein activation and internalizationFEBS JOURNAL, Issue 13 2009Alexander Faussner The bradykinin B2 receptor is coupled to G protein Gq/11 and becomes sequestered into intracellular compartments after activation. To more closely define the receptor sequences involved in these processes and their functions, we systematically mutated all three intracellular loops (ICLs), either as point mutations or in groups of three to five amino acids to Ala, obtaining a total of 14 mutants. All constructs were stably expressed in HEK 293 cells and, with the exception of triple mutant DRY , AAA, retained the ability to specifically bind [3H]bradykinin. The binding affinities at 4 or 37 °C of several mutants differed considerably from those determined for the wild-type receptor, indicating an allosteric connection between the conformation of the binding site and that of the ICLs. Mutations in ICL-1 strongly reduced surface expression without affecting G protein signaling or [3H]bradykinin internalization. Two cluster mutants in the middle of ICL-2 containing basic residues displayed considerably reduced potencies, whereas two mutations in ICL-3 resulted in receptor conformations that were considered to be semi-active, based on the observation that they responded with phosphoinositide hydrolysis to compounds normally considered to be antagonists. This, and the fact that a cluster mutant at the C-terminal end of ICL-3 was signaling incompetent, hint at the involvement of ICL-2 and ICL-3 in Gq/11 activation, albeit with different functions. None of the mutants displayed reduced ligand-induced receptor internalization, indicating that the loops are not essential for this process. No conclusion could be drawn, however, with regard to the role of the DRY sequence, as the corresponding triplet mutation lacked binding capability. [source] The periplasmic peptidyl prolyl cis,trans isomerases PpiD and SurA have partially overlapping substrate specificitiesFEBS JOURNAL, Issue 13 2008Krista H. Stymest One of the rate-limiting steps in protein folding has been shown to be the cis,trans isomerization of proline residues, catalysed by a range of peptidyl prolyl cis,trans isomerases (PPIases). In the periplasmic space of Escherichia coli and other Gram-negative bacteria, two PPIases, SurA and PpiD, have been identified, which show high sequence similarity to the catalytic domain of the small PPIase parvulin. This observation raises a question regarding the biological significance of two apparently similar enzymes present in the same cellular compartment: do they interact with different substrates or do they catalyse different reactions? The substrate-binding motif of PpiD has not been characterized so far, and no biochemical data were available on how this folding catalyst recognizes and interacts with substrates. To characterize the interaction between model peptides and the periplasmic PPIase PpiD from E. coli, we employed a chemical crosslinking strategy that has been used previously to elucidate the interaction of substrates with SurA. We found that PpiD interacted with a range of model peptides independently of whether they contained proline residues or not. We further demonstrate here that PpiD and SurA interact with similar model peptides, and therefore must have partially overlapping substrate specificities. However, the binding motif of PpiD appears to be less specific than that of SurA, indicating that the two PPIases might interact with different substrates. We therefore propose that, although PpiD and SurA have partially overlapping substrate specificities, they fulfil different functions in the cell. [source] MULTILEVEL FRAMING: AN ALTERNATIVE UNDERSTANDING OF BUDGET CONTROL IN PUBLIC ENTERPRISESFINANCIAL ACCOUNTABILITY & MANAGEMENT, Issue 2 2010Lars Fallan This paper addresses the question as to why there tends to be recurring budget deviations in public sector service organizations. In the public sector, budgets and actuals are loosely coupled, and budgets may serve other institutional functions than control purposes. However, little research has addressed how the framing of budget information may explain the different functions of the budgets as control devices. The paper argues that the valence of budget deviations varies between organizations, and that organizations that have a positively oriented valence towards budget surpluses have a propensity to underspend the budgets. Consequently, organizations that have a positively oriented valence towards budget deficits tend to overspend the budgets. The empirical part analyses the budget situations in the Central Bank of Norway and in a large university hospital in Norway. In the case of the Bank, it was found that underspending of budgets was framed as performance measures indicating high organizational efficiency. The Hospital, on the other hand, showed a different picture as budget deficits were the situation during all years studied. One main finding was the key actors' roles as translators of the society's expectations as to the fulfilling of the organizations' missions. These translators function as mediators between the institutional context and pressures, the organizations' goals and the internal budget processes. The conventional wisdom that the budget also acts as a means of communication and as symbols and ritual acts that reflect the institutional contingencies of the organizations, is further developed by describing how organizations' goals valence the role of budgets. [source] Hydrologic versus geomorphic limitation on CPOM storage in stream ecosystemsFRESHWATER BIOLOGY, Issue 8 2008MELANIE J. SMALL Summary 1. Stream ecosystems are the products of interactions between hydrology, geomorphology and ecology, but examining all three components simultaneously is difficult and rarely attempted. Frequently, either geomorphology or hydrology is treated as invariable or static. 2. To examine the validity of treating either hydrology or geomorphology as static, we studied the individual and combined effects of hydrology and channel geomorphology on coarse particulate organic matter (CPOM) storage. Using data from an experimental leaf release in a hydrologically regulated stream we created a simple numerical model. This allowed us to quantify the relative influence of CPOM trapping and CPOM retention on total long-term CPOM storage under variable regimes of flood frequency and geomorphic structure. 3. CPOM storage is a function of supply, flood frequency and the type and frequency of in-stream structures. In-stream structures perform two distinct functions, trapping and retention, whose relative importance in leaf storage changes with stream hydrology. Trapping is more important for CPOM storage in streams with few floods, while retention is more important in streams with frequent floods. Different structures (e.g. boulders, large wood, small wood) perform these functions at different efficiencies. We found that large wood trapped two to three times more leaves than the bank, but that the bank retained leaves two to three times more efficiently. 4. A modelled channel with five times the amount of large wood as the study channel (a ,wood restoration') initially stored 14% more leaves than the modelled ,natural' channel. After six floods, however, the modelled wood restoration channel stored 50% less CPOM than the natural channel as the large wood had high trapping but poor retention. The modelled natural channel contained structures that could both trap and retain. Thus, as different structures performed different functions, the structural complexity buffered the stream allochthonous energy base against changes in hydrology through its balance of trapping and retention. 5. As the frequency of floods increased, the spatial distribution of CPOM became increasingly patchy as storage was driven entirely by structures with high retention. Thus, the coupling of flood frequency and geomorphic structure influenced CPOM availability, which in turn has ramifications for the entire stream food web. [source] Interspecific relationships among growth, mortality and xylem traits of woody species from New ZealandFUNCTIONAL ECOLOGY, Issue 2 2010Sabrina E. Russo Summary 1.,Wood density is considered a key functional trait influencing the growth and survival of woody plants and has been shown to be related to a slow,fast rate-of-living continuum. Wood density is, however, an emergent trait arising from several vascular properties of wood, including the diameter and frequency of xylem conduits. 2.,We aimed to test the hypotheses that there is a set of inter-related trade-offs linked to the different functions of wood, that these trade-offs have direct consequences for tree growth and survival and that these trade-offs underlie the observed correlations between wood density and demographic rates. We evaluated the covariation between xylem anatomical traits among woody species of New Zealand and whether that covariation had the potential to constrain variation in wood density and demographic rates. 3.,Several xylem traits were strongly correlated with each other, but wood density was not correlated with any of them. We also found no significant relationships between wood density and growth or mortality rate. Instead, growth was strongly related to xylem traits associated with hydraulic capacity (conduit diameter and a conductivity index) and to maximum height, whereas mortality rate was strongly correlated only with maximum height. The diameter and frequency of conduits exhibited a significant negative relationship, suggesting a trade-off, which restricted variation in wood density and growth rate, but not mortality rate. 4.,Our results suggest, for woody species in New Zealand, that growth rate is more closely linked to xylem traits determining hydraulic conductance, rather than wood density. We also found no evidence that denser woods conferred higher survival, or that risk of cavitation caused by wide conduits increased mortality. 5.,In summary, we found little support for the idea that wood density is a good proxy for position along a fast,slow rate-of-living continuum. Instead, the strong, negative relationship between vessel diameter and frequency may constrain the realized diversity of demographic niches of tree species in New Zealand. Trade-offs in function therefore have the potential to shape functional diversity and ecology of forest communities by linking selection on structure and function to population-level dynamics. [source] Structural Characterization of Multi-Quantum Wells in Electroabsorption-Modulated Lasers by using Synchrotron Radiation Micrometer-BeamsADVANCED MATERIALS, Issue 18 2010Lorenzo Mino Advanced optoelectronic devices require monolithic integration of different functions at chip level. This is the case of multi-quantum well (MQW) electro absorption modulated lasers (EMLs) realized by using the selective area growth (SAG) technique, and which can be employed in long-distance, high-frequency optical fiber communication applications. We demonstrate that a micrometer-resolved X-ray beam available at third-generation synchrotron radiation sources allows direct measurement of determinant structural parameters of MQW EML structures. [source] Analysis of the structure and expression of the 30K protein genes in silkworm, Bombyx moriINSECT SCIENCE, Issue 1 2007QUAN SUN Abstract A group of lipoproteins with molecular sizes of approximately 30 kDa, referred to as 30K proteins, are synthesized in fat body cells in the fifth instar larvae of silkworm, Bombyx mori. Analyzing the silkworm genome and its expressed sequence tags (ESTs), we found 10 genes encoding 30K proteins, which are mainly distributed in three subfamilies. Of these, seven coding proteins were found to harbor the degrading sites of 30kP protease A, although the number of degrading sites may be different. As some potential core promoters and regulatory elements were supposed to be essential for gene transcription, the expression profiles of these genes were examined by semi-quantitative reverse transcription polymerase chain reaction. Eight 30K protein genes were detected to express luxuriantly in the fat body, while two were hardly expressed. Such results suggest that these 30K proteins may have different functions, and their adjacent regulatory elements play a crucial role in regulating their transcription. [source] Molecular cloning of feline tumour necrosis factor receptor type I (TNFR I) and expression of TNFR I and TNFR II in lymphoid cells in catsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2003T. Mizuno Summary Tumour necrosis factor (TNF)-, is a pro-inflammatory cytokine produced by many types of cells. It has been shown that two distinct TNF receptors (TNFRs), TNFR type I (TNFR I) and TNFR type II (TNFR II), have different functions in signal transduction, which is possibly associated with the development of a variety of diseases. In this study, we isolated a feline TNFR I cDNA clone and analysed the expression of TNFR I and TNFR II mRNA in feline lymphoid cells. The deduced amino acid sequence of feline TNFRI cDNA showed 75.8, 62.5 60.9 and 72.1% similarity with those of its human, mouse, rat, and pig counterparts, respectively. The feline TNFR I cDNA was shown to encode extracellular, transmembrane and intracellular domains fundamentally conserved in the homologues of other species. Expression of TNFR I and TNFR II mRNAs was shown to be up-regulated in feline peripheral blood mononuclear cells (PBMC) by stimulation with concanavalin A. Five of six feline lymphoma cell lines were shown to express both TNFR I and TNFR II mRNAs. The expression of TNFR I in PBMC was up-regulated in cats infected with feline immunodeficiency virus (FIV), whereas the expression of TNFR II in PBMC was not different between FIV-infected cats and uninfected cats. The present study indicate that expression of TNFR I and TNFR II may be associated with disease progression, especially in retrovirus infections in cats. [source] Attitudes of Egyptian nursing home residents towards staying in a nursing home: a qualitative studyINTERNATIONAL JOURNAL OF OLDER PEOPLE NURSING, Issue 4 2009Thomas Boggatz RN Aim., The aim of this study was to identify the attitudes of Egyptian nursing home residents towards staying in a nursing home and to differentiate between various types of these attitudes. Background., The number of older persons in Egypt who require nursing care is increasing. In response, nursing homes in bigger cities like Cairo were founded, although family care seems to be the prevalent norm. Methods., Semi-structured guideline interviews were performed with 21 residents from four different nursing homes in Cairo. Interviews were analyzed using qualitative content analysis. Findings., One category of resident was those who were sent to the nursing home by persons closely related to them. Another category made their own decision to move to a nursing home. Relationships with social networks and self-help abilities are factors of importance in influencing decision-making. Conclusion., Nursing homes in Egypt fulfil different functions for different types of older persons. Charitable institutions are a last resort for those with no income and a disrupted social network. For better-off older persons, nursing homes may provide the benefits of socialising with peers and receiving medical treatment. [source] Differential Expression of Estrogen Receptor-Related Receptor , and Estrogen Receptors , and , in Osteoblasts In Vivo and In Vitro,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2002Edith Bonnelye Abstract The orphan nuclear estrogen receptor-related receptor (ERR) , is expressed by osteoblastic cells, is known to transactivate at least one osteoblast-associated gene osteopontin (OPN) and plays a functional role in osteoprogenitor cell proliferation and differentiation. To dissect further the role of ERR-, in bone formation, we compared its expression to that of the estrogen receptor (ER) , and ER-, in rat calvaria (RC) and fetal tibia in vivo and in RC and rat bone marrow (RBM) cells in vitro. We found that ERR-, is highly and widely expressed in most, if not all, cells in RC cell cultures from early proliferation stages through mineralized nodule formation; ER-, was localized similarly but at lower levels and ER-,, although present, was barely detectable. These patterns of expression in vitro correlated with what we observed in vivo in sections of 21-day fetal RC, in which ERR-, appeared to be more highly expressed than either of the ERs. Interestingly, ERR-, also is highly expressed in RBM cells, while ER-, and ER-, mRNA is expressed, but at lower levels. Moreover, we found that ERR-,, ER-,, and ER-, were all expressed in osteoblasts in fetal and adult tibia whereas they were expressed differentially in calvaria in vivo in subsets of osteoblasts, supporting the hypothesis that ERR-, may interact with one or both of the ERs in those osteoblasts in which they are coexpressed and that all three receptors may be required for bone formation but at different times and for different functions. [source] FGF and FGFR signaling in chondrodysplasias and craniosynostosisJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2005P.J. Marie Abstract The first experimental mouse model for FGF2 in bone dysplasia was made serendipitously by overexpression of FGF from a constitutive promoter. The results were not widely accepted, rightfully drew skepticism, and were difficult to publish; because of over 2,000 studies published on FGF-2 at the time (1993), only a few reported a role of FGF-2 in bone growth and differentiation. However, mapping of human dwarfisms to mutations of the FGFRs shortly, thereafter, made the case that bone growth and remodeling was a major physiological function for FGF. Subsequent production of numerous transgenic and targeted null mice for several genes in the bone growth and remodeling pathways have marvelously elucidated the role of FGFs and their interactions with other genes. Indeed, studies of the FGF pathway present one of the best success stories for use of experimental genetics in functionally parsing morphogenetic regulatory pathways. What remains largely unresolved is the pleiotropic nature of FGF-2. How does it accelerate growth in one cell then stimulate apoptosis or retard growth for another cell in the same type of tissue? Some of the answers may come through distinguishing the FGF-2 protein isoforms, made from alternative translation start sites, these appear to have substantially different functions. Although we have made substantial progress, there is still much to be learned regarding FGF-2 as a most complex, enigmatic protein. Studies of genetic models in mice and human FGFR mutations have provided strong evidence that FGFRs are important modulators of osteoblast function during membranous bone formation. However, there is some controversy regarding the effects of FGFR signaling in human and murine genetic models. Although significant progress has been made in our understanding of FGFR signaling, several questions remain concerning the signaling pathways involved in osteoblast regulation by activated FGFR. Additionally, little is known about the specific role of FGFR target genes involved in cranial bone formation. These issues need to be addressed in future in in vitro and in vivo approaches to better understand the molecular mechanisms of action of FGFR signaling in osteoblasts that result in anabolic effects in bone formation. J. Cell. Biochem. © 2005 Wiley-Liss, Inc. [source] Mathematical modeling of appendicular bone growth in glaucous-winged gullsJOURNAL OF MORPHOLOGY, Issue 1 2009James L. Hayward Abstract Development of locomotor activity is crucial in tetrapods. In birds, this development leads to different functions for hindlimbs and forelimbs. The emergence of walking and flying as very different complex behavior patterns only weeks after hatching provides an interesting case study in animal development. We measured the diaphyseal lengths and midshaft diameters of three wing bones (humerus, ulna, and carpometacarpus) and three leg bones (femur, tibiotarsus, and tarsometatarsus) of 79 juvenile (ages 0,42 days) and 13 adult glaucous-winged gulls (Larus glaucescens), a semiprecocial species. From a suite of nine alternative mathematical models, we used information-theoretic criteria to determine the best model(s) for length and diameter of each bone as a function of age; that is, we determined the model(s) that obtained the best tradeoff between the minimized sum of squared residuals and the number of parameters used to fit the model. The Janoschek and Holling III models best described bone growth, with at least one of these models yielding an R2 , 0.94 for every dimension except tarsometatarsus diameter (R2 = 0.87). We used the best growth models to construct accurate allometric comparisons of the bones. Early maximal absolute growth rates characterize the humerus, femur, and tarsometatarsus, bones that assume adult-type support functions relatively early during juvenile development. Leg bone lengths exhibit more rapid but less sustained relative growth than wing bone lengths. Wing bone diameters are initially smaller than leg bone diameters, although this relationship is reversed by fledging. Wing bones and the femur approach adult length by fledging but continue to increase in diameter past fledging; the tibiotarsus and tarsometatarsus approach both adult length and diameter by fledging. In short, the pattern of bone growth in this semiprecocial species reflects the changing behavioral needs of the developing organism. J. Morphol., 2009. © 2008 Wiley-Liss, Inc. [source] Temperature functions of the rate coefficients of net N mineralization in sandy arable soils.JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 4 2004Part I. Derivation from laboratory incubations Abstract This study aimed to experimentally determine adequate temperature functions for the rate coefficients of net N mineralization in sandy arable soils from NW Germany. Long-term laboratory incubations were carried out in seven sandy arable soils at 3°C, 10°C, 19°C, 28°C, and 35°C in order to derive the rate coefficients of a simultaneous two-pool first-order kinetic equation. Thereby we differentiated between a small, fast mineralizable N pool, comprising mainly fresh residues, and a larger, slowly mineralizable N pool of old, humified organic matter. The rate coefficients were plotted against temperature, and fits of several different functions were tested: Arrhenius, Q10, and multiple non-mechanistic equations. The two derived rate coefficients showed very different temperature functions. Especially in critical temperature ranges (<5/10°C, >30/35°C) common Q10 functions failed to fit well, and, only below 10°C, the Arrhenius functions were in agreement with mean measured rate coefficients. Over the studied temperature range, only relatively complex, multiple equations could adequately account for the observed patterns. In addition, temperature functions that have been derived earlier from loess soils from NW Germany were found not to be transferable to the sandy arable soils studied. Thus, the results strongly question the use of the same Arrhenius or Q10 function or the same rate modifying factor for different N pools as well as for different soils as is generally done in models. Evaluations with field measurements of net N mineralization in part II of the paper (Heumann and Böttcher, 2004) will show which functions perform best in the field. Die Temperaturfunktionen der Reaktionskoeffizienten der N-Nettomineralisation in sandigen Ackerböde nI. Ableitung aus Laborinkubationen Untersuchungsziel war die experimentelle Bestimmung adäquater Temperaturfunktionen für die Reaktionskoeffizienten der N-Nettomineralisation in sandigen Ackerböden NW-Deutschlands. Anhand von Langzeit-Laborinkubationen bei 3, 10, 19, 28 und 35,°C wurden für sieben sandige Ackerböden die Reaktionskoeffizienten zweier N-Pools mit Reaktionskinetik erster Ordnung ermittelt. Dadurch konnte zwischen einem kleineren, schnell mineralisierbaren N-Pool, der hauptsächlich frische Residuen umfasst, und einem größeren, langsam mineralisierbaren N-Pool aus überwiegend alter humifizierter organischer Substanz unterschieden werden. Die ermittelten Reaktionskoeffizienten wurden gegen die Temperatur aufgetragen und verschiedene Funktionen angepasst: Arrhenius-, Q10 - und multiple nicht-mechanistische Gleichungen. Die Temperaturfunktionen der beiden Reaktionskoeffizienten unterschieden sich stark. Besonders innerhalb kritischer Temperaturbereiche (<5/10,°C, >30/35,°C) war die Übereinstimmung üblicher Q10 -Funktionen schlecht, und nur unterhalb von 10,°C stimmten die Arrhenius-Funktionen mit den mittleren gemessenen Reaktionskoeffizienten überein. Über den gesamten untersuchten Temperaturbereich konnten nur relativ komplexe, multiple Gleichungen die beobachteten Verläufe angemessen nachzeichnen. Weiterhin waren die Temperaturfunktionen, die ehemals an norddeutschen Lössböden ermittelt wurden, nicht auf die untersuchten sandigen Ackerböden übertragbar. Daher stellen die Ergebnisse den Gebrauch derselben Arrhenius- oder Q10 -Funktion sowie gleicher Ratenfaktoren für verschiedene N-Pools und auch für verschiedene Böden stark in Frage. In Teil II der Arbeit (Heumann and Böttcher, 2004) wird anhand einer Überprüfung mit Messungen der N-Nettomineralisation im Feld gezeigt, welche Funktionen die beste Übereinstimmung im Freiland erbringen. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||