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Major Contribution (major + contribution)
Selected AbstractsPost-last glacial maximum expansion from Iberia to North Africa revealed by fine characterization of mtDNA H haplogroup in TunisiaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Lotfi Cherni Abstract The first large-scale fine characterization of Tunisian H lineages clarifies that the post-Last glacial maximum expansion originating in Iberia not only led to the resettlement of Europe but also of North Africa. We found that 46% of 81 Tunisian H lineages subscreened for 1,580 bp in mtDNA coding region were affiliated with H1 and H3 subhaplogroups, which are known to have originated in Iberia. Although no signs of local expansion were detected, which would allow a clear dating of their introduction, the younger and less diverse Tunisian H1 and H3 lineages indicate Iberia as the radiating centre. Major contributions from historical migrations to this Iberian genetic imprint in Tunisia were ruled out by the mtDNA gene pool similarity between Berber/Arab/cosmopolitan samples and some "Andalusian" communities, settled by the descendents of the "Moors" who once lived in Iberia for 10 centuries (between 8th and 17th centuries), before being expelled to Tunisia. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Not by Rent Alone: Analysing the Pro-Poor Functions of Small-Scale Fisheries in Developing CountriesDEVELOPMENT POLICY REVIEW, Issue 3 2010Christophe Béné The dominant view in academic and policy arenas is increasingly one in which the major contribution of capture fisheries to development should be derived from the capacity of society to maximise the economic rent of fishery resources. Drawing upon empirical experience from the South, this article highlights the potentially disastrous consequences that a universal implementation of the rent-maximisation model would have in developing countries, and argues that a more gradual approach would be preferable. The welfare function of small-scale fisheries, namely, their capacities to provide labour and cash income to resource-poor households, should be preserved until the appropriate macroeconomic conditions for rent-maximisation and redistribution are fulfilled. [source] Frontal nasal prominence expression driven by Tcfap2a relies on a conserved binding site for STAT proteinsDEVELOPMENTAL DYNAMICS, Issue 5 2006Amy L. Donner Abstract The AP-2 transcription factor family is linked with development of the head and limbs in both vertebrate and invertebrate species. Recent evidence has also implicated this gene family in the evolution of the neural crest in chordates, a critical step that allowed the development and elaboration of the vertebrate craniofacial skeleton. In mice, the inappropriate embryonic expression of one particular AP-2 gene, Tcfap2a, encoding AP-2,, results in multiple developmental abnormalities, including craniofacial and limb defects. Thus, Tcfap2a provides a valuable genetic resource to analyze the regulatory hierarchy responsible for the evolution and development of the face and limbs. Previous studies have identified a 2-kilobase intronic region of both the mouse and human AP-2, locus that directs expression of a linked LacZ transgene to the facial processes and the distal mesenchyme of the limb bud in transgenic mice. Further analysis identified two highly conserved regions of ,200,400 bp within this tissue-specific enhancer. We have now initiated a transgenic and biochemical analysis of the most important of these highly conserved regions. Our analysis indicates that although the sequences regulating face and limb expression have been integrated into a single enhancer, different cis -acting sequences ultimately control these two expression domains. Moreover, these studies demonstrate that a conserved STAT binding site provides a major contribution to the expression of Tcfap2a in the facial prominences. Developmental Dynamics 235:1358,1370, 2006. © 2006 Wiley-Liss, Inc. [source] Victor Horsley's Contribution to Jacksonian EpileptologyEPILEPSIA, Issue 11 2005Mervyn J. Eadie Summary:,Purpose: To describe Victor Horsley's contribution to John Hughlings Jackson's understanding of the mechanisms involved in the generalization of convulsive epileptic seizures. Methods: I reviewed Horsley's writings and other relevant late 19th century medical literature. Results: Horsley's combination of strategically sited surgical lesions and cerebral cortex stimulation studies in experimental animals showed that, contrary to Hughlings Jackson's earlier belief, epileptic activity arising in one cerebral hemisphere had to spread to the contralateral hemisphere before bilateral convulsing could occur. Conclusions: On the basis of well-designed experiments, Horsley made a major contribution to the understanding of epileptic seizure propagation mechanisms. [source] An update on cyathostomins: Anthelmintic resistance and worm controlEQUINE VETERINARY EDUCATION, Issue 10 2008J. B. Matthews Summary Intestinal nematodes are an important cause of equine disease. Of these parasites, the Cyathostominae are the most important group, both in terms of their prevalence and their pathogenicity. Cyathostomin infections are complex and control is further complicated by ever-increasing levels of resistance to some of the commonly used anthelmintics. There are no new equine anthelmintics under development, so it is imperative that the efficacy of any currently-effective drug classes be maintained for as long as possible. It is believed that the proportion of refugia (i.e. the percentage of parasites not exposed to a drug at each treatment) is one of the most crucial factors in determining the rate at which anthelmintic resistance develops. It is important, therefore, that levels of refugia be taken into account when designing nematode control programmes for horses. This can be assisted by knowledge of the local epidemiology of the infection, supplemented by faecal egg count analysis to identify those animals that are making the major contribution to pasture contamination. This type of rational nematode control requires equine veterinary surgeons to get involved in designing and implementing deworming programmes. The advice given must be based on a combination of knowledge of cyathostomin biology and epidemiology as well as an awareness of the parasite population's current drug sensitivity and a sound history of husbandry at the establishment. As anthelmintic resistance will be the major constraint on the future control of cyathostomins, researchers are now actively investigating this area. Studies are underway to develop tests that will enable earlier detection of anthelmintic resistance and an assay that will help identify those horses that require anthelmintic treatments targeted at intestinal wall larvae. [source] Effects of angiogenic regulators on in vitro proliferation and cytokine secretion by native human acute myelogenous leukemia blastsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2003Øystein Bruserud Abstract: Angiogenesis seems to be important in the pathogenesis of acute myelogenous leukemia (AML). The endothelial cell proliferation and microvessel formation are regulated by a wide range of soluble mediators, including angiogenin, angiopoietin-2, basic fibroblast growth factors, vascular endothelial growth factor (VEGF), VEGF-D, angiostatin and endostatin. In the present study, it has been investigated whether these mediators have an additional direct effect on the proliferation and cytokine release by native human AML blasts. AML cells derived from a large group of consecutive patients were investigated. All these mediators could alter the proliferation and cytokine release [interleukin (IL) 1,, IL6, IL8, tumor necrosis factor ,] for a minority of patients. Alteration of spontaneous proliferation by at least one mediator was detected in five of 38 patients; whereas, altered cytokine (Flt3-ligand, granulocyte-macrophage colony-stimulating factor, stem cell factor)-dependant proliferation was observed for 10 patients. Growth enhancement was most frequently observed, whereas growth inhibition was uncommon. The effects on AML blast proliferation were often dependant on or were modulated by the presence of the three hematopoietic growth factors. Based on the present results, it is concluded that angioregulatory mediators have additional growth-enhancing effects directly on the AML blasts for certain patients. However, based on the results from this investigation and previous studies it is suggested that their major contribution to the pathogenesis of AML is through their effects on regulation of bone marrow angiogenesis, and future studies of these mediators in AML should probably focus on these effects. [source] Involvement of the human frontal eye field and multiple parietal areas in covert visual selection during conjunction searchEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2000Tobias Donner Abstract Searching for a target object in a cluttered visual scene requires active visual attention if the target differs from distractors not by elementary visual features but rather by a feature conjunction. We used functional magnetic resonance imaging (fMRI) in human subjects to investigate the functional neuroanatomy of attentional mechanisms employed during conjunction search. In the experimental condition, subjects searched for a target defined by a conjunction of colour and orientation. In the baseline condition, subjects searched for a uniquely coloured target, regardless of its orientation. Eye movement recordings outside the scanner verified subjects' ability to maintain fixation during search. Reaction times indicated that the experimental condition was attentionally more demanding than the baseline condition. Differential activations between conditions were therefore ascribed to top-down modulation of neural activity. The frontal eye field, the ventral precentral sulcus and the following posterior parietal regions were consistently activated: (i) the postcentral sulcus; (ii) the posterior; and (iii) the anterior part of the intraparietal sulcus; and (iv) the junction of the intraparietal with the transverse occipital sulcus. Parietal regions were spatially distinct and displayed differential amplitudes of signal increase with a maximal amplitude in the posterior intraparietal sulcus. Less consistent activation was found in the lateral fusiform gyrus. These results suggest an involvement of the human frontal eye field in covert visual selection of potential targets during search. These results also provide evidence for a subdivision of posterior parietal cortex in multiple areas participating in covert visual selection, with a major contribution of the posterior intraparietal sulcus. [source] The adaptive nature of cultureEVOLUTIONARY ANTHROPOLOGY, Issue 3 2003Article first published online: 19 MAY 200, Michael S. Alvard Abstract Some have argued that the major contribution of anthropology to science is the concept of culture. Until very recently, however, evolutionary anthropologists have largely ignored culture as a topic of study. This is perhaps because of the strange bedfellows they would have to maintain. Historically, anthropologists who claimed the focus of cultural anthropology tended to be anti-science, anti-biology, or both. Paradoxically, a segment of current mainstream cultural anthropology has more or less abandoned culture as a topic. It is particularly ironic that in spite of a growing awareness among evolutionary anthropologists that culture is critical for understanding the human condition, the topic of culture has fallen out of favor among many "cultural" anthropologists. 1,2 [source] Crystal structure of Fab198, an efficient protector of the acetylcholine receptor against myasthenogenic antibodiesFEBS JOURNAL, Issue 13 2001Konstantinos Poulas The crystal structure of the Fab fragment of the rat monoclonal antibody 198, with protective activity for the main immunogenic region of the human muscle acetylcholine receptor against the destructive action of myasthenic antibodies, has been determined and refined to 2.8 Å resolution by X-ray crystallographic methods. The mouse anti-lysozyme Fab D1.3 was used as a search model in molecular replacement with the amore software. The complementarity determining regions (CDR)-L2, CDR-H1 and CDR-H2 belong to canonical groups. Loops CDR-L3, CDR-H2 and CDR-H3, which seem to make a major contribution to binding, were analyzed and residues of potential importance for antigen-binding are examined. The antigen-binding site was found to be a long crescent-shaped crevice. The structure should serve as a model in the rational design of very high affinity humanized mutants of Fab198, appropriate for therapeutic approaches in the model autoimmune disease myasthenia gravis. [source] Studies in Urban Ecology: the First Wave of Biological Invasion by Pistacia chinensis in Armidale, New South Wales, AustraliaGEOGRAPHICAL RESEARCH, Issue 3 2000J. M. B. Smith Biological invasions by deliberately introduced organisms seriously compromise the integrity of ecosystems, but their early stages have seldom been documented, especially in urban contexts. Since the 1940s, the small Asian tree Pistacia chinensis has been widely planted in streets and gardens in Armidale, New South Wales, Australia, where it makes a major contribution to the autumn colours that are exploited to promote the city. Numerous wild plants are now becoming established in and near Armidale. This ongoing biological invasion may have been accelerated by the large size of the initial (planted) population, and by the presence of efficient avian seed dispersers. It is now at the stage of the first wild generation reaching reproductive maturity. While it is probably still possible to halt the invasion, various human factors appear to make this an unlikely prospect. [source] Crustal versus asthenospheric relaxation and post-seismic deformation for shallow normal faulting earthquakes:the Umbria,Marche (central Italy) caseGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2000R. Riva Summary Following a normal mode approach for a stratified viscoelastic earth, we investigate the effects induced by shallow normal faulting earthquakes, on surface post-seismic vertical displacement and velocity at the surface, when stress relaxation occurs in the crust or in the asthenosphere. The modelled earthquake is a moderate one characteristic of some slowly deforming plate boundaries in the central Mediterranean region. We focus on the Umbria,Marche (central Italy) region where deep seismic reflection studies (CROP03) and the 1997 earthquake sequence clearly show a seismogenic layer decoupled from the lower crust by a sizeable transition zone. Accordingly, the crust is subdivided into three layers: an elastic upper crust, a transition zone and a low-viscosity lower crust. The fault is embedded in the upper crust. The layered viscoelastic structure of the crust and mantle imposes a pattern and scale on the modelled coseismic and post-seismic deformation with a major contribution from the transition crustal zone and low-viscosity lower crust, stress relaxation in the mantle being negligible. We show that significant vertical deformation rates of the order of 1 mm yr, 1 could be expected for a shallow and moderate event such as the recent Umbria,Marche earthquake for viscosity values of 1019 and 1018 Pa s in the crustal transition zone and lower crust, respectively. [source] Measuring consumer perception of product creativity: Impact on satisfaction and purchasabilityHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 3 2009Diana Horn In the current value-based economy, product creativity is a potential resource for organizations to compete, thus emphasizing the need for product creativity measurement. Two studies were performed to refine and validate a previously tested model and measurement of consumer perception of product creativity: one with web-based evaluations (N = 208) of chairs and lamps and one with paper-based evaluations (N = 105) of individually selected products. Results of exploratory factor analyses indicated three main product creativity factors: Affect, Importance, and Novelty, which explained 72% of the common variance. Results of stepwise regressions indicated that the Affect factor significantly predicts (65% of the explained variance) willingness to purchase creative consumer products. One major contribution of this research is the finding that affect is as equally (R2 = .28) important as novelty (R2 = .25) in consumer perception of product creativity. Theoretical and practical implications are discussed for the Affect, Importance, and Novelty product creativity factors, and general creativity guidelines are provided for consumer product design. © 2009 Wiley Periodicals, Inc. [source] Virtual environments in machinery safety analysis and participatory ergonomicsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 5 2007Timo J. Määttä The objective of this work was to evaluate the impact of Virtual Environments (VEs) on safety analysis and participatory ergonomics. The developed method Safety Analysis with Virtual Environments (SAVE) is based on Participatory Ergonomics (PE), Task Analysis (TA), Work Safety Analysis (WSA), the standard EN 1050, and three-dimensional (3-D) functional modeling of the objects being analyzed. The materials of this work comprised machinery systems of six plants in a steel factory, which were implementing ongoing modernization projects. The results indicate that the SAVE method was applicable for safety analysis in the machinery layout design phase. According to the results, 58% of all identified hazards in a steel factory could be identified with VEs. A common understanding of designs, possibilities of evaluating and developing the system by the workers, and of providing training for operators and maintenance persons were the major contribution when using VEs in a safety analysis and applying a participative ergonomics approach. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 435,443, 2007. [source] Composite suspended sediment particles and flocculation in glacial meltwaters: preliminary evidence from Alpine and Himalayan basinsHYDROLOGICAL PROCESSES, Issue 9 2002J. C. Woodward Abstract Research over the last decade has shown that the suspended sediment loads of many rivers are dominated by composite particles. These particles are also known as aggregates or flocs, and are commonly made up of constituent mineral particles, which evidence a wide range of grain sizes, and organic matter. The resulting in situ or effective particle size characteristics of fluvial suspended sediment exert a major control on all processes of entrainment, transport and deposition. The significance of composite suspended sediment particles in glacial meltwater streams has, however, not been established. Existing data on the particle size characteristics of suspended sediment in glacial meltwaters relate to the dispersed mineral fraction (absolute particle size), which, for certain size fractions, may bear little relationship to the effective or in situ distribution. Existing understanding of composite particle formation within freshwater environments would suggest that in-stream flocculation processes do not take place in glacial meltwater systems because of the absence of organic binding agents. However, we report preliminary scanning electron microscopy data for one Alpine and two Himalayan glaciers that show composite particles are present in the suspended sediment load of the meltwater system. The genesis and structure of these composite particles and their constituent grain size characteristics are discussed. We present evidence for the existence of both aggregates, or composite particles whose features are largely inherited from source materials, and flocs, which represent composite particles produced by in-stream flocculation processes. In the absence of organic materials, the latter may result solely from electrochemical flocculation in the meltwater sediment system. This type of floc formation has not been reported previously in the freshwater fluvial environment. Further work is needed to test the wider significance of these data and to investigate the effective particle size characteristics of suspended sediment associated with high concentration outburst events. Such events make a major contribution to suspended sediment fluxes in meltwater streams and may provide conditions that are conducive to composite particle formation by flocculation. Copyright © 2002 John Wiley & Sons, Ltd. [source] Performance comparison of some dynamical and empirical downscaling methods for South Africa from a seasonal climate modelling perspectiveINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 11 2009Willem A. Landman Abstract The ability of advanced state-of-the-art methods of downscaling large-scale climate predictions to regional and local scale as seasonal rainfall forecasting tools for South Africa is assessed. Various downscaling techniques and raw general circulation model (GCM) output are compared to one another over 10 December-January-February (DJF) seasons from 1991/1992 to 2000/2001 and also to a baseline prediction technique that uses only global sea-surface temperature (SST) anomalies as predictors. The various downscaling techniques described in this study include both an empirical technique called model output statistics (MOS) and a dynamical technique where a finer resolution regional climate model (RCM) is nested into the large-scale fields of a coarser GCM. The study addresses the performance of a number of simulation systems (no forecast lead-time) of varying complexity. These systems' performance is tested for both homogeneous regions and for 963 stations over South Africa, and compared with each other over the 10-year test period. For the most part, the simulations method outscores the baseline method that uses SST anomalies to simulate rainfall, therefore providing evidence that current approaches in seasonal forecasting are outscoring earlier ones. Current operational forecasting approaches involve the use of GCMs, which are considered to be the main tool whereby seasonal forecasting efforts will improve in the future. Advantages in statistically post-processing output from GCMs as well as output from RCMs are demonstrated. Evidence is provided that skill should further improve with an increased number of ensemble members. The demonstrated importance of statistical models in operation capacities is a major contribution to the science of seasonal forecasting. Although RCMs are preferable due to physical consistency, statistical models are still providing similar or even better skill and should still be applied. Copyright © 2008 Royal Meteorological Society [source] The Theory and Practice of Economic Governance in EMU Revisited: What Have we Learnt About Commitment and Credibility?,JCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 4 2006WALTRAUD SCHELKLE This special issue asks commentators who made seminal contributions to our understanding of economic governance to revisit their analyses. This introductory article discusses the example of a major contribution, namely the ,advantage of tying one's hands' (Giavazzi and Pagano, 1988), relating it to the other contributions along the way. [source] Wet chemical synthesis of low bulk density aluminium hydroxide powderJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2003JK Pradhan Abstract Fine, low bulk density aluminium hydroxide powdered gel was prepared by the mild base hydrolysis of an aqueous solution of aluminium sulfate with hydrazine hydrate. Parameters such as method of addition of reactant, initial concentration of Al3+, mole ratio, final pH and hydrolysis temperature have a profound effect on the lightness and particle size of the powder. Optimized conditions showed that the final pH, Al3+ concentration and method of addition of reactant have a major contribution on the formation of lighter grade powder. Experiments conducted using other bases also produced lighter particles under similar conditions. Deviation from the optimized conditions led to formation of a higher bulk density product. Copyright © 2003 Society of Chemical Industry [source] Evaluation of electroosmotic drag coefficient of water in hydrated sodium perfluorosulfonate electrolyte polymerJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 9 2009Liuming Yan Abstract The electroosmotic drag coefficient of water molecules in hydrated sodium perfluorosulfonate electrolyte polymer is evaluated on the basis of the velocity distribution functions of the sodium cations and water molecules with an electric field applied using molecular dynamics simulations. The simulation results indicate that both velocity distribution functions of water molecules and of sodium cations agree well with the classic Maxwellian velocity distribution functions when there is no electric field applied. If an electric field is applied, the distribution functions of velocity component in directions perpendicular to the applied electric field still agree with the Maxwellian velocity distribution functions but with different temperature parameters. In the direction of the applied electric field, the electric drag causes the velocity distribution function to deviate from the Maxwellian velocity distribution function; however, to obey the peak shifted Maxwellian distribution function. The peak shifting velocities coincide with the average transport velocities induced by the electric field, and could be applied to the evaluation of the electroosmotic drag coefficient of water. By evaluation of the transport velocities of water molecules in the first coordination shells of sodium cations, sulfonate anion groups, and in the bulk, it is clearly shown that the water molecules in the first coordination shell of sodium cations are the major contribution to the electroosmotic drag and momentum transfer from water molecules within the first coordination shell to the other water molecules also contributes to the electroosmotic drag. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009 [source] Aging well , the role of minimally invasive aesthetic dermatological procedures in women over 65JOURNAL OF COSMETIC DERMATOLOGY, Issue 1 2010Uwe Wollina MD Summary Background, The western world is getting older. Aging well has become the new target of preventative medicine. Aesthetic dermatology can contribute to this quest. Females over 65 represent an important and growing group of consumers of cosmetic procedures. In this group, there is a paucity of scientific evaluation of aesthetic procedures. Objective, To review the use of minimally invasive procedures for facial rejuvenation in women over 65. Methods, Drawing from both the literature and personal experience, the opportunities, modifications, and limitations of minimally invasive techniques for facial rejuvenation in older women are considered. Results, In this older age group, dermal fillers, chemical and laser peels, and nonablative photorejuvenation remain useful and can each be used as stand-alone treatments. In this age group, botulinum toxin (BTX) injections are more often used in combination with other procedures. Conclusions, With respect to aesthetic procedures, women over 65 are different from younger women. More scientific investigation is necessary to better meet needs of this growing part of the population. Available data suggest that aesthetic dermatology can make a major contribution to the complex matter of aging well. [source] Detection of Sublethal Thermal Injury in Salmonella enterica Serotype Typhimurium and Listeria monocytogenes Using Fourier Transform Infrared (FT-IR) Spectroscopy (4000 to 600 cm,1)JOURNAL OF FOOD SCIENCE, Issue 2 2008H.M. Al-Qadiri ABSTRACT:, Fourier transform infrared (FT-IR) spectroscopy (4000 to 600 cm,1) was utilized to detect sublethally heat-injured microorganisms: Salmonella enterica serotype Typhimurium ATCC 14028, a Gram-negative bacterium, and Listeria monocytogenes ATCC 19113, a Gram-positive bacterium. A range of heat treatments (N= 2) at 60 °C were evaluated: 0D (control), 2D, 4D, 6D, and 8D using a D60 °C (S. enterica serotype Typhimurium ATCC 14028 = 0.30 min, L. monocytogenes ATCC 19113 = 0.43 min). The mechanism of cell injury appeared to be different for Gram-negative and Gram-positive microbes as observed from differences in the 2nd derivative transformations and loadings plot of bacterial spectra following heat treatment. The loadings for PC1 and PC2 confirmed that the amide I and amide II bands were the major contribution to spectral variation, with relatively small contributions from C-H deformations, the antisymmetric P==O stretching modes of the phosphodiester nucleic acid backbone, and the C-O-C stretching modes of polysaccharides. Using soft independent modeling of class analogy (SIMCA), the extent of injury could be predicted correctly at least 83% of the time. Partial least squares (PLS) calibration analysis was constructed using 5 latent variables for predicting the bacterial counts for survivors of the different heat treatments and yielded a high correlation coefficient (R= 0.97 [S. enterica serotype Typhimurium] and 0.98 [L. monocytogenes]) and a standard error of prediction (SEP= 0.51 [S. enterica serotype Typhimurium] and 0.39 log10 CFU/mL [L. monocytogenes]), indicating that the degree of heat injury could be predicted. [source] Does fertilizer use respond to rainfall variability?AGRICULTURAL ECONOMICS, Issue 2 2010Panel data evidence from Ethiopia Fertilizer use; Rainfall; Highlands of Ethiopia; Panel data Abstract In this article, we use farmers' actual experiences with changes in rainfall levels and their responses to these changes to assess whether patterns of fertilizer use are responsive to changes in rainfall patterns. Using panel data from the Central Highlands of Ethiopia matched with corresponding village-level rainfall data, the results show that the intensity of current year's fertilizer use is positively associated with higher rainfall levels experienced in the previous year. Rainfall variability, on the other hand, impacts fertilizer use decisions negatively, implying that variability raises the risks and uncertainty associated with fertilizer use. Abundant rainfall in the previous year could depict relaxed liquidity constraints and increased affordability of fertilizer, which makes rainfall availability critical in severely credit-constrained environments. In light of similar existing literature, the major contribution of the study is that it uses panel data to explicitly examine farmers' responses to actual weather changes and variability. [source] In vivo and in vitro MR spectroscopic profile of central neurocytomasJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2003Rama Jayasundar PhD Abstract This study reports in vivo and in vitro magnetic resonance spectroscopic findings in two cases of central neurocytomas (CNC) confirmed by immunohistochemistry. Volume localized in vivo proton magnetic resonance spectroscopy (MRS) was carried out before surgery using a point resolved spectroscopy (PRESS) sequence with a repetition time of six seconds and an echo time of 135 msec. Normal spectrum was obtained from gray matter from a volunteer for comparison. 1H and 31P in vitro MRS studies were carried out at 9.4 T on the extracts prepared from the surgically excised tumors. The in vivo spectra showed prominent glycine (Gly) and choline (Cho) and low N-acetyl aspartate compared to the normal. The Gly peak was assigned using the in vitro studies. These studies showed that the major contribution to the Cho peak observed in vivo is from phosphocholine. A combination of the presence of NAA and an increased Gly in the proton MR spectrum could be a characteristic feature of CNCs, which are rare intraventricular tumors of neuronal origin. J. Magn. Reson. Imaging 2003;17:256,260. © 2003 Wiley-Liss, Inc. [source] Long-lasting coexpression of nestin and glial fibrillary acidic protein in primary cultures of astroglial cells with a major participation of nestin+/GFAP, cells in cell proliferationJOURNAL OF NEUROSCIENCE RESEARCH, Issue 8 2006Solène Sergent-Tanguy Abstract Nestin, a currently used marker of neural stem cells, is transiently coexpressed with glial fibrillary acidic protein (GFAP) during development and is induced in reactive astrocytes following brain injury. Nestin expression has also been found in cultures of astroglial cells, but little is known about the fate and the mitotic activity of nestin-expressing cells in this in vitro model. The present study reveals a long-lasting expression of nestin in primary cultures of astroglial cells derived from the rat brain. Over 70% of the cells were nestin+ at 12 weeks, with a large majority coexpressing the GFAP astrocytic marker. Time-course analyses supported a transition from a nestin+/GFAP, to a nestin+/GFAP+ phenotype over time, which was further increased by cell cycle arrest. Interestingly, double staining with Ki67 revealed that over 90% of cycling cells were nestin+ whereas only 28% were GFAP+ in a population consisting of almost equivalent numbers of nestin+ and GFAP+ cells. These observations indicated that nestin+/GFAP, cells are actively engaged in mitotic activity, even after 2 weeks in vitro. Part of these cells might have retained properties of neural stem cells, insofar as 10% of cells in a primary culture of glial cells were able to generate neurospheres that gave rise to both neurons and astrocytes. Further studies will be necessary to characterize fully the proliferating cells in primary cultures of glial cells, but our present results reveal a major contribution of the nestin+/GFAP, cells to the increase in the number of astrocytes, even though nestin+/GFAP+ cells proliferate also. © 2006 Wiley-Liss, Inc. [source] Principal-component analysis of multiscale data for process monitoring and fault diagnosisAICHE JOURNAL, Issue 11 2004Seongkyu Yoon Abstract An approach is presented to multivariate statistical process control (MSPC) for process monitoring and fault diagnosis based on principal-component analysis (PCA) models of multiscale data. Process measurements, representing the cumulative effects of many underlying process phenomena, are decomposed by applying multiresolution analysis (MRA) by wavelet transformations. The decomposed process measurements are rearranged according to their scales, and PCA is applied to these multiscale data to capture process variable correlations occurring at different scales. Choosing an orthonormal mother wavelet allows each principal component to be a function of the process variables at only one scale level. The proposed method is discussed in the context of other multiscale approaches, and illustrated in detail using simulated data from a continuous stirred tank reactor (CSTR) system. A major contribution of the paper is to extend fault isolation methods based on contribution plots to multiscale approaches. In particular, once a fault is detected, the contributions of the variations at each scale to the fault are computed. These scale contributions can be very helpful in isolating faults that occur mainly at a single scale. For those scales having large contributions to the fault, one can further compute the variable contributions to those scales, thereby making fault diagnosis much easier. A comparison study is done through Monte Carlo simulation. The proposed method can enhance fault detection and isolation (FDI) performance when the frequency content of a fault effect is confined to a narrow-frequency band. However, when the fault frequency content is not localized, the multiscale approaches perform very comparably to the standard single-scale approaches, and offer no real advantage. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2891,2903, 2004 [source] Comparison of single pot and multiphase high shear wet granulation processes related to excipient compositionJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2009K. Giry Abstract At present time, industrial production imperatives can require the transposition of a formulation from one equipment to another. In order to evaluate the impact of such a switch on the properties of granules and tablets, investigations were undertaken on formulations manufactured both in a single pot mixer-granulator-dryer (high shear granulator with in situ double jacket vacuum drying) and in a multiphase equipment (high shear granulator/fluid bed dryer). Principal component analysis highlighted the major contribution of the binder ratio on granule size distribution, flow and packing ability whereas the relative ratio of mannitol and lactose, used as fillers, mainly impacted on compressibility and tablet cohesion. In the studied domain, the lubricant ratio did not explain the considered responses. Statistical analysis (comparison of means, analysis of variance and PCA) showed that both processes led to products with similar characteristics which demonstrated the ability of the processes to produce granules with close quality. However, Fielder®/Niro® granule characteristic data were found to be more dispersed, thus demonstrating a higher sensitivity of the multiphase process to formulation changes. Technological properties of granules and tablets were found to be maintained or improved therefore securing the switch from single pot to multiphase equipments. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3761,3775, 2009 [source] A reconstruction of development of the periodic table based on history and philosophy of science and its implications for general chemistry textbooksJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 1 2005Angmary Brito The objectives of this study are: (a) elaboration of a history and philosophy of science (HPS) framework based on a reconstruction of the development of the periodic table; (b) formulation of seven criteria based on the framework; and (c) evaluation of 57 freshman college-level general chemistry textbooks with respect to the presentation of the periodic table. The historical reconstruction of the periodic table showed that the periodicity of the elements could be construed as an inductive generalization or as a function of the atomic theory. There is considerable controversy with respect to the nature of Mendeleev's contribution, and various alternatives are discussed: ordered domain; empirical law; and a theory with limited explanatory power. Accommodation of the elements according to their physicochemical properties is considered to be the major contribution of the periodic table by all textbooks, followed by contrapredictions of previously unknown elements (30 textbooks), and novel predictions (corrections of atomic mass) of known elements (10 textbooks). The relative importance of accommodation and prediction within an HPS framework is generally ignored. Few textbooks have attempted to explore the possible cause of periodicity in the table and very few textbooks have explored the nature of Mendeleev's contribution. The development of the periodic table as a sequence of heuristic principles in the form of a convincing argument has been ignored. The textbook approach of emphasizing that the development of the periodic table was an inductive generalization, and that Mendeleev had no model or theory, does not facilitate the spirit of critical inquiry that led the scientists to grapple with alternative interpretations, conflicts, and controversies. It is concluded that the development of the periodic table went through a continual critical appraisal (conflict and controversy), in which scientists presented various tentative theoretical ideas to understand the observed phenomena. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 42: 84,111, 2005 [source] INFLUENCE OF STORAGE TEMPERATURE ON COOLING INTENSITY OF TOPICAL EMULSIONS CONTAINING ENCAPSULATED MENTHOLJOURNAL OF SENSORY STUDIES, Issue 1 2008VIVIAN ZAGUE ABSTRACT The cooling intensity of topical emulsions added with encapsulated or free menthol was evaluated by a screened and trained panel recruited based on the American Society for Testing and Materials method. A sensory panel composed of 10 trained judges performed the evaluation of samples stored at 22 ± 2C for 24 h and, after 28 days of storage, at 37.0 ± 0.5C. The obtained data were analyzed by analysis of variance and Tukey's test. The results showed an increase of cooling intensity as a function of encapsulated menthol concentration. The opposite was observed in samples added with free menthol, which may have caused sensory fatigue. Storage at 37 ± 0.5C for 28 days had no impact on the cooling intensity of emulsions containing encapsulated menthol, demonstrating high stability and suggesting its application in cooling skin care products. In contrast, emulsions added with free menthol showed a drastic decrease of cooling intensity at 37 ± 0.5C. PRATICAL APPLICATIONS This article deals with sensory assessment of the cooling intensity of topical emulsions added with encapsulated menthol under accelerated storage conditions. In all, the work is a major contribution to (1) investigating the feasibility of sensory analysis for evaluating the sensory properties of topical products during storage; (2) verifying the cooling intensity of topical emulsions containing encapsulated menthol; and (3) evaluating the effect of encapsulation of menthol on its stability during accelerated storage conditions. [source] Coumarins and phenolic fingerprints of oak and Brazilian woods extracted by sugarcane spiritJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Alexandre Ataide da Silva Abstract A total of 25 sugarcane spirit extracts of six different Brazilian woods and oak, commonly used by cooperage industries for aging cachaça, were analyzed for the presence of 14 phenolic compounds (ellagic acid, gallic acid, vanillin, syringaldehyde, synapaldehyde, coniferaldehyde, vanillic acid, syringic acid, quercetin, trans -resveratrol, catechin, epicatechin, eugenol, and myricetin) and two coumarins (scopoletin and coumarin) by HPLC-DAD-fluorescence and HPLC-ESI-MSn. Furthermore, an HPLC-DAD chromatographic fingerprint was build-up using chemometric analysis based on the chromatographic elution profiles of the extracts monitored at 280,nm. Major components identified and quantified in Brazilian wood extracts were coumarin, ellagic acid, and catechin, whereas oak extracts shown a major contribution of catechin, vanillic acid, and syringaldehyde. The main difference observed among oak and Brazilian woods remains in the concentration of coumarin, catechin, syringaldehyde, and coniferaldehyde. The chemometric analysis of the quantitative profile of the 14 phenolic compounds and two coumarins in the wood extracts provides a differentiation between the Brazilian wood and oak extracts. The chromatographic fingerprint treated by multivariate analysis revealed significant differences among Brazilian woods themselves and oak, clearly defining six groups of wood extracts: (i) oak extracts, (ii) jatobá extracts, (iii) cabreúva-parda extracts, (iv) amendoim extracts, (v) canela-sassafrás extracts and (vi) pequi extracts. [source] Daytime sympathetic hyperactivity in OSAS is related to excessive daytime sleepinessJOURNAL OF SLEEP RESEARCH, Issue 3 2007VINCENZO DONADIO Summary The aim of this study was to investigate the relationships among sympathetic hyperactivity, excessive daytime sleepiness (EDS) and hypertension in obstructive sleep apnoea syndrome (OSAS). Ten newly diagnosed OSAS patients with untreated EDS and daytime hypertension underwent polysomnography (PSG) and daytime measurements of plasma noradrenaline (NA), ambulatory blood pressure (BP), muscle sympathetic nerve activity (MSNA) by microneurography and objective assessment of EDS before and during 6 months of compliance-monitored continuous positive airway pressure (CPAP) treatment. One month after the start of CPAP, BP, MSNA and NA were significantly lowered, remaining lower than baseline also after 3 and 6 months of treatment. CPAP use caused a significant improvement of sleep structures, and reduced EDS. A statistical correlation analysis demonstrated that EDS was not correlated with sleep measures obtained from baseline PSG (% sleep stages, apnoea and arousal index, mean oxygen saturation value), whereas daytime sleepiness was significantly correlated with MSNA. Furthermore, MSNA and BP showed no correlation. Our data obtained from selected patients suggest that the mechanisms inducing EDS in OSAS are related to the degree of daytime sympathetic hyperactivity. Additionally, resting MSNA was unrelated to BP suggesting that factors other than adrenergic neural tone make a major contribution to OSAS-related hypertension. The results obtained in this pilot study need, however, to be confirmed in a larger study involving more patients. [source] Functional characterization of transcription factor binding sites for HNF1-alpha, HNF3-beta (FOXA2), HNF4-alpha, Sp1 and Sp3 in the human prothrombin gene enhancerJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2003H. Ceelie Summary.,Background:,Prothrombin is a key component in blood coagulation. Overexpression of prothrombin leads to an increased risk of venous thrombosis. Therefore, the study of the transcriptional regulation of the prothrombin gene may help to identify mechanisms of overexpression. Objectives:,The aim of our study was to localize the regions within the prothrombin enhancer responsible for its activity, to identify the proteins binding to these regions, and to establish their functional importance. Methods:,We constructed a set of prothrombin promoter 5, deletion constructs containing the firefly luciferase reporter gene, which were transiently transfected in HepG2, HuH7 and HeLa cells. Putative transcription factor (TF) binding sites were evaluated by electrophoretic mobility shift assays. The functional importance of each TF binding site was evaluated by site directed mutagenesis and transient transfection of the mutant constructs. Results:,We confirmed the major contribution of the enhancer region to the transcriptional activity of the prothrombin promoter. Analysis of this region revealed putative binding sites for hepatocyte nuclear factor HNF4, HNF3-beta and specificity protein(Sp)1. We identified six different TFs binding to three evolutionary conserved sites in the enhancer: HNF4-alpha (site 1), HNF1-alpha, HNF3-beta and an as yet unidentified TF (site 2) and the ubiquitously expressed TFs Sp1 and Sp3 (site 3). Mutagenesis studies showed that loss of binding of HNF3-beta resulted in a considerable decrease of enhancer activity, whereas loss of HNF4-alpha or Sp1/Sp3 resulted in milder reductions. Conclusions:,The prothrombin enhancer plays a major role in regulation of prothrombin expression. Six different TFs are able to bind to this region. At least three of these TFs, HNF4-alpha, HNF3-beta and Sp1/Sp3, are important in regulation of prothrombin expression. [source] | ||||||||||||||||||||||||||||||||||