Full Understanding (full + understanding)

Distribution by Scientific Domains

Selected Abstracts

Long-term effects of ungulates on phytophagous insects

Abstract 1.,Most plants interact with a diverse suite of herbivores, allowing the opportunity for the existence of positive and negative interactions between highly dissimilar organisms. However, most studies on herbivorous interactions have been performed under the assumption that they occur mainly between similar species. Consequently, ecologists are still far from a full understanding of the ecological factors that determine insect population dynamics. 2.,In this study, a 7-year field experiment was conducted that manipulated the presence of ungulates to evaluate their effects on the abundance, attack rate, and survival of four guilds of co-occurring herbivorous insects living on the same host plant: seed predators, stem borers, gall makers and sap suckers. These four guilds differed in habits and behaviour, the first three being sessile and endophytic and the last being free-living. 3.,This study shows that the abundance of all four guilds was negatively affected by ungulates. However, the effect on attack rate differed among guilds, as mammals do not affect the seed predator attack rate. Ungulates also differentially affected insect survival, ingesting only seed predators and gall makers. 4.,In summary, this study suggests that diverse mechanisms may affect different insect guilds in different ways. Therefore, competition between disparate herbivores appears to be complex and can be provoked by multiple mechanisms. [source]

Current and Future Trends of Climatic Extremes in Switzerland

Martin Beniston
This article provides an overview of extreme climatic events that are a feature of current and future climate that require full understanding if they are to be assessed in terms of social and economic costs. A review is made of the type of events that are important in mid-latitudes, with examples taken from the heat waves, floods and wind-storms that have affected Switzerland during the twentieth century. Regional climate model results are also presented for a scenario conducted over Europe. These simulations suggest that there may be significant shifts in the frequency and intensity of many forms of extremes as a warmer global climate progressively replaces current climate. In view of the potential losses in human, economic and environmental terms, extreme events and their future evolution need to carefully assessed in order to formulate appropriate adaptation strategies aimed at minimizing the negative impacts that extremes are capable of generating. [source]

Sleeping with baby: an internet-based sampling of parental experiences, choices, perceptions, and interpretations in a western industrialized context

J. J. McKenna
Abstract Mothers and infants sleeping within proximity to each other (co-sleeping) represents normal, healthy, and expectable human behaviour, especially if mothers breastfeed. Yet, western health officials generally recommend against particularly one form of co-sleeping known as bedsharing. This study explores these issues and especially highlights parental accounts of their sleep practices, interpretations, and reflections based on detailed narratives or ,ethnohistories.' The sample involves a self-selected sub-group of over 200 mostly middle-class mothers from Canada, the United States, Australia, and Great Britain. Mothers report how and why they adopted co-sleeping practices, how satisfied they are (or were) with their decisions, and what benefits they think they or their infants derived from their co-sleeping practices. Also included in the reports are a surprisingly high number of parents who think they may have saved their infant's life by bedsharing, data heretofore never reported in the literature. The formulation of medical policies, we suggest, ultimately must be informed by a full understanding of how parents actually think about and subsequently structure their infant's sleep, what their goals and expectations are, and by an awareness of the emotional factors motivating parents to choose certain sleeping arrangements over others. The results reveal that many factors coalesce, often in unique ways, under unique circumstances, family by family, to determine where babies sleep and why. We conclude that sleeping arrangements are not solely determined by medically based recommendations, but also by the method of feeding, the particular needs of a particular infant, and the needs of mothers and fathers to get more sleep. While baby sleep locations and sleep patterns change in the first year of life, nighttime sleeping arrangements almost always reflect the nature of family values and the quality of social relationships at any given time. We conclude that these factors, alongside widely known independent SIDS risk factors, must also be acknowledged and respected if we are ever to achieve an effective and inclusive public health approach to the question of creating safe sleep environments for infants and children. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Mathematical framework towards the analysis of a generic traffic marker

Nasser-Eddine Rikli
Abstract DiffServ architecture has been widely adopted for the provision of QoS over the Internet. This makes the full understanding of its operation imperative. We believe that only mathematical analysis may have the power of such goal. As the heart of a DiffServ router is the token bucket algorithm, a generic one, with two-colours marking, is to be considered here. A mathematical framework will be first developed for its analysis. Then, assuming an input traffic with Poisson arrivals and Exponential packet lengths, and a memoryless token bucket system, the two types of generated streams will be statistically characterized through their distributions and averages. This analysis will be carried out for two types of buckets, one with infinite size and a second with finite size. It will be shown how the derived equations will allow the prediction of the output traffic streams for given bucket and input traffic stream parameters. The paper will be then complemented by conclusions and suggestions. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Study of the anti-lactic acid bacteria compounds in table olives

Eduardo Medina
Summary The analysis and formation of anti-lactic acid bacteria compounds in olive brines was performed for the main worldwide olive varieties intended for table olives. The results demonstrated that the growth of lactic acid bacteria in the brines of olives non-treated with NaOH is, in some way, variety dependant. Likewise, the most active antimicrobial compound, the dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol, was not detected in fresh fruits but it was formed during brining from the hydrolysis of oleuropein and this reaction was enzymatically catalysed. Thus, the inactivation of the enzyme by heating the olives produced (i) an accumulation of oleuropein in olives and brines, (ii) the inhibition of the formation of antimicrobials and (iii) the growth of Lactobacillus pentosus in olive brines. These results provide tools for a full understanding of the growth or inhibition of lactic acid bacteria during fermentation of table olives. [source]

Immunoassays: their history, development and current place in food science and technology

Graham A. Bonwick
Abstract The purpose of this paper is to introduce the reader to immunoassays. This paper is the first in a themed issue of the Journal in which a number of papers have been brought together in order to demonstrate the types and variety of immunoassays, which are currently available. Indeed it might be said that all an analyst needs to do is to name a molecule and somewhere there will now be an immunoassay for the detection of that molecule. This obviously is not entirely accurate, however immunoassays do provide a powerful tool, which can be used in the analysis and quality control of food materials. For both the novice and the experienced worker the specialist terminology of a subject presents an initial barrier, which must be overcome before full understanding is achieved. In this paper an attempt is made to introduce the important terms with which the reader should be familiar and to try to set the various technologies in context. The various basic methods are described and the theoretical and practical basis of more sophisticated assays now being devised are introduced. [source]

Assessing spatial probabilistic distributional differences in the common space between schizophrenics and normal controls based on a novel automated probabilistic pattern analysis method

Bang-Bon Koo
Abstract Because of the complex nature of the human brain, a full understanding of its various group specific variation factors such as volume, shape, and location related to age, gender, ethnic, and disease might be provided in both structural and functional neuroimaging studies. To serve this purpose, a novel approach for characterizing the group variability information using group specific labeled probabilistic maps was introduced in this article. An automatic labeling technique was applied to encode group specific probabilistic information for each region of interests (ROIs) covering the overall cortical region and a probabilistic pattern analytic method was proposed to assess the difference in the spatial extent between 70 schizophrenics and 70 controls in the common space. From our proposed method, we found major differences in 17 ROIs that had shown large variation in schizophrenics. Most of these ROIs were in the frontal and the temporal lobe and only three ROIs were in the parietal and the occipital lobe. The ROIs highlighted through our proposed method could be connected with previous morphological findings on schizophrenia and it also might be considered in functional analysis. As a result, our method could provide intuitive information on group difference relevant to the overall anatomical variability in the substructural level. Thus, it could be used as a prompting system to search and examine the regions of the brain that are worthy of further precise analysis by various sub-cortical region based group studies in assessing specific patterns related to diseases. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 310,324, 2008 [source]

Universal ideals and particular constraints of social citizenship: the Chinese experience of unifying rights and responsibilities

Chack Kie Wong
This study looks at the perceptions of citizens in a modern Chinese society and explores whether social rights and responsibilities are unified at both ideal and practice levels. It finds that the conception that the Chinese have a weak image of social rights is no longer true. The Chinese are generally ,right-deficit' at the practice level. It is also found that there are wide gaps between ideal rights and practice rights, and between ideal responsibilities and practice responsibilities, except in components affected by cultural, contextual and institutional factors. The findings suggest that, for a full understanding of social citizenship, it is necessary to look at both ideal and practice levels of social citizenship. Cultural, contextual and institutional factors are identified as moderating people's behaviour and preferences in regard to social citizenship. [source]

Understanding the multiple meanings of ,inbreeding' and ,effective size' for genetic management of African rhinoceros populations

Stanton Braude
Abstract Although some African rhinoceros populations are currently increasing, others are critically endangered. Even healthy populations are extensively managed in the wild and in captivity. While political and demographic considerations are of primary concern, many decisions are made in the name of genetic management. Such decisions should be informed by a full understanding of the multiple meanings of inbreeding and effective population size. In this essay, we examine inbreeding and effective size of wild and captive populations of African rhinoceroses. We conclude by showing how misunderstanding of effective size and Franklin's 50/500 rule can make a crucial difference in informing management decisions. Résumé Bien que certaines populations de rhinocéros africains soient actuellement en augmentation, d'autres sont en danger critique. Męme les populations saines sont gérées trčs activement dans la nature et en captivité. Alors que les considérations politiques et démographiques soient les principaux motifs d'inquiétude, de nombreuses décisions sont prises au nom de la gestion génétique. Ces décisions devraient se faire en pleine connaissance des multiples implications de l'inbreeding et de ce qu'est une taille de population nécessaire. Dans cet essai, nous examinons l'inbreeding et la taille nécessaire des populations sauvages et captives de rhinocéros africains. Nous concluons en montrant comment une mauvaise compréhension de la taille nécessaire et de la rčgle 50/500 de Franklin peut entraîner une différence cruciale lorsqu'il s'agit de prendre, en connaissance de cause, les décisions opportunes. [source]

Inflammatory bowel disease: Established and evolving considerations on its etiopathogenesis and therapy

Modern studies of inflammatory bowel disease (IBD) pathogenesis have been pursued for about four decades, a period of time where the pace of progress has been steadily increasing. This progress has occurred in parallel with and is largely due to developments in multiple basic scientific disciplines that range from population and social studies, genetics, microbiology, immunology, biochemistry, cellular and molecular biology, and DNA engineering. From this cumulative and constantly expanding knowledge base the fundamental pillars of IBD pathogenesis appear to have been identified and consolidated during the last couple of decades. Presently there is a general consensus among basic IBD investigators that both Crohn's disease (CD) and ulcerative colitis (UC) are the result of the combined effects of four basic components: global changes in the environment, the input of multiple genetic variations, alterations in the intestinal microbiota, and aberrations of innate and adaptive immune responses. There is also agreement on the conclusion that none of these four components can by itself trigger or maintain intestinal inflammation. A combination of various factors, and most likely of all four factors, is probably needed to bring about CD or UC in individual patients, but each patient or set of patients seems to have a different combination of alterations leading to the disease. This would imply that different causes and diverse mechanisms underlie IBD, and this could also explain why every patient displays his or her own clinical manifestations and a personalized response to therapy, and requires tailored approaches with different medications. While we are becoming increasingly aware of the importance of this individual variability, we have only a superficial notion of the reasons why this occurs, as hinted by the uniqueness of the genetic background and of the gut flora in each person. So, we are apparently facing the paradox of having to deal with the tremendous complexity of the mechanisms responsible for chronic intestinal inflammation in the setting of each patient's individuality in the response to this biological complexity. This obviously poses considerable challenges to reaching a full understanding of IBD pathogenesis, but being aware of the difficulties is the first step in finding answers to them. [source]

Mechanical Response of Single Plant Cells to Cell Poking: A Numerical Simulation Model

Rong Wang
Abstract Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The force-deformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties. (Managing editor: Wei Wang) [source]

Experimental observation of a strange temporal oscillation of X-ray Pendellösung fringes

Jun-ichi Yoshimura
As a strange property not explained by existing theories, it has been known from experiment that X-ray moiré and Pendellösung interference fringes show a small spatial oscillation in the beam path in free space that the diffraction image carrying those fringes is propagated after emerging from the crystal. In connection with the investigation into this strange fringe oscillation, it has been found, by an experiment successively recording Pendellösung-fringe topographs using an X-ray CCD camera, that X-ray Pendellösung fringes also show a small temporal oscillation. Characteristics of this temporal Pendellösung-fringe oscillation, namely irregularities in the fringe profile, the manner of fringe oscillation and a reciprocal correlation between oscillation amplitude and fringe contrast, are shown to be very similar to those of the previously reported spatial oscillation of moiré and Pendellösung fringes. Therefore this temporal oscillation is supposed to have the same origin as the spatial oscillation, revealing another section of the same phenomenon. This discovery of the temporal oscillation advances a step nearer to the full understanding of this strange phenomenon, while disclosing a new property of Pendellösung fringes. As well as the above, a three-dimensional profile representation (surface plot) is given of the image of Pendellösung fringes, to make it clear that unidentified fine intensity modulations, called subfringes in this paper, are produced superposed on the main fringe system. Overall inspection of the intensity profiles of the fringe-imaged topographs suggests that temporal intensity oscillations also occur on a more global scale than the extension of individual fringes, as an unidentified action of the wavefield. [source]

Origin of the X-ray magnetic circular dichroism at the L -edges of the rare-earths in RxR1,x,Al2 systems

Jesús Chaboy
An X-ray magnetic circular dichroism (XMCD) study performed at the rare-earth L2,3 -edges in the RxR1,x,Al2 compounds is presented. It is shown that both R and R, atoms contribute to the XMCD recorded at the L -edges of the selected rare-earth, either R or R,. The amplitude of the XMCD signal is not directly correlated to the magnetization or to the value of the individual (R, R,) magnetic moments, but it is related to the molecular field acting on the rare-earth tuned in the photoabsorption process. This result closes a longstanding study of the origin of the XMCD at the L -edge of the rare-earths in multi-component systems, allowing a full understanding of the exact nature of these signals. [source]

Review article: nuclear receptors and liver disease , current understanding and new therapeutic implications

Aliment Pharmacol Ther,30, 816,825 Summary Background, The important role of nuclear receptors and their contribution to liver function in both physiological and pathological conditions has come to attention in recent years and has advanced our understanding of several liver diseases. These findings led to the introduction of targeting nuclear receptors as treatment strategies for various liver diseases. Aims, To review the new insights brought by the study of nuclear receptors to our understanding of the molecular basis of various liver diseases, and to summarize some of the recent studies that evaluated the efficacy of targeting nuclear receptor as a new approach in treating liver diseases. Methods, Review of articles, using PubMed and article references. Results, Nuclear receptor ligands in patients with liver diseases have been associated with a variety of toxicities. Some clinical results have not met the expectations predicted from animal experiments. Mechanistic explanations at the molecular level are needed for preventing toxicity and improving outcomes from nuclear receptor ligands. Conclusion, The use of various nuclear receptor ligands in liver diseases is a promising approach that can benefit many patients suffering from these devastating diseases. However, we are far from a full understanding of the molecular mechanisms by which these receptors work. [source]

Predictors of health-related quality of life in patients with chronic liver disease

Summary Background, Patient-reported outcomes like health-related quality of life (HRQL) have become increasingly important for full assessment of patients with chronic liver diseases (CLD). Aim, To explore the relative impact of different types of liver disease on HRQL as well as predictors of HRQL domains in CLD. Methods, Our HRQL databases with Short-Form 36 (SF-36) data were used. Scores for each of SF-36 scales (PF , physical functioning, RP , role functioning, BP , bodily pain, GH , general health, VT , vitality, SF , social functioning, RE , role emotional and MH , mental health, MCS , mental component score, PCS , physical component score) were compared between different types of CLD as well as other variables. Results, Complete data were available for 1103 CLD patients. Demographic and clinical data included: age 54.2 ± 12.0 years, 40% female, 761 (69%) with cirrhosis. Analysis revealed that age correlated significantly (P < 0.05) with worsening HRQL on every scale of the SF-36. Female patients had more HRQL impairments in PF, RP, BP, GH, VT and MH scales of SF-36 (, scale score: 6.6,10.7, P < 0.05). Furthermore, cirrhotic patients had more impairment of HRQL in every scale of SF-36 (, scale score: 6.6,43.0, P < 0.05). In terms of diagnostic groups, non-alcoholic fatty liver disease patients showed more impairment of HRQL. Conclusions, Analysis of this large CLD cohort suggests that a number of important clinicodemographic factors are associated with HRQL impairment. These findings contribute to the full understanding of the total impact of CLD on patients' health. [source]

Pegylated interferons: chemical and clinical differences

G. R. Foster
Summary Pegylated interferon therapy for the treatment of chronic hepatitis C virus provides significant increases in sustained virological response rates compared with standard interferons. Two pegylated interferons are now available and are used in conjunction with ribavirin to maximize response rates in infected patients. The two pegylated interferons, peginterferon, -2a and peginterferon, -2b, differ substantially in terms of their chemical and structural characteristics, pharmacokinetic and pharmacodynamic properties, and dosing and administration. A full understanding of the differences between the two drugs is important to maximize the clinical benefits. Controlled studies designed to characterize the effects of the two drugs on viral kinetics and sustained virological response rates are emerging and may help to shed additional light on the use of these compounds in patients with chronic hepatitis C. [source]

Polymer Morphology: A Guide to Macromolecular Self-Organization

D.C. Bassett
Abstract The study of polymer morphology continues to be the principal means of acquiring knowledge and understanding of macromolecular self-organization. Longstanding problems of the nature of melt-crystallized lamellae and spherulitic growth have been resolved, bringing understanding of how characteristic properties such as a broad melting range and spatially-varying mechanical response are inherent in spherulitic morphologies. This reflects the distinctive features of the crystallization of long molecules, i.e. that they impede each other and, for faster growth, form rough basal surfaces. Knowledge of morphology is an essential accompaniment to the informed development of advanced polymeric materials and a full understanding of their structure/property relations. [source]

Distribution of the genus Hypoplectrus (Teleostei: Serranidae) in the Greater Caribbean Region: support for a color-based speciation

MARINE ECOLOGY, Issue 2 2010
Alfonso Aguilar-Perera
Abstract The reef-associated fish genus Hypoplectrus (Serranidae), endemic to the western Atlantic Ocean, represents an ideal model to study speciation within a potentially highly dispersive (marine) ecosystem, because it consists of a complex of at least 10 morphs differentiated primarily by coloration. Although several recent studies on genetics, diet, and fertilization reveal little to no difference between the Hypoplectrus color morphs, there is still not a full understanding of what keeps these morphs distinct or drives their variation. Ecological information is needed alongside the genetic information to better understand this variation. Based on presence/absence records from scientific literature and direct observations in coral reefs, this work examined the distribution of the genus Hypoplectrus in the Greater Caribbean region. Some color morphs occurred simultaneously at given locations, but others showed geographic restrictions. Using cluster and nMDS analyses, we found three major groupings according to distribution: (i) widespread (Hypoplectrus puella, Hypoplectrus unicolor, and Hypoplectrus nigricans), (ii) less widespread (Hypoplectrus indigo, Hypoplectrus gummigutta, Hypoplectrus chlorurus, Hypoplectrus aberrans, and Hypoplectrus guttavarius), and (iii) geographically confined or segregated (Hypoplectrus gemma, Hypoplectrus providencianus). Geographic sections selected for the Greater Caribbean (eastern, western and northern) were dominated by at least three widely distributed Hypoplectrus morphs. New geographic records of some color morphs were documented and compared to previous established distribution ranges in the Greater Caribbean. [source]

Uncertainty and Endogenous Selection of Economic Equilibria

Pasquale Scaramozzino
ABSTRACT This paper presents a model of coordination failures based on market power and local oligopoly. The economy exhibits a multiplicity of Pareto-ranked equilibria. The introduction of uncertainty generates an endogenous equilibrium selection process, due to a strategic use of information by firms. The economy is more likely to settle on some equilibria than on others. We argue that a full understanding of these robustness criteria is needed before any policy which is intended to help coordinate the level of activity to a Pareto-dominant outcome can be successfully implemented. [source]

Basic science and translational research in female pelvic floor disorders: Proceedings of an NIH-sponsored meeting

Anne M. Weber
Abstract Aims To report the findings of a multidisciplinary group of scientists focusing on issues in basic science and translational research related to female pelvic floor disorders, and to produce recommendations for a research agenda for investigators studying female pelvic floor disorders. Methods A National Institutes of Health (NIH)-sponsored meeting was held on November 14,15, 2002, bringing together scientists in diverse fields including obstetrics, gynecology, urogynecology, urology, gastroenterology, biomechanical engineering, neuroscience, endocrinology, and molecular biology. Recent and ongoing studies were presented and discussed, key gaps in knowledge were identified, and recommendations were made for research that would have the highest impact in making advances in the field of female pelvic floor disorders. Results The meeting included presentations and discussion on the use of animal models to better understand physiology and pathophysiology; neuromuscular injury (such as at childbirth) as a possible pathogenetic factor and mechanisms for recovery of function after injury; the use of biomechanical concepts and imaging to better understand the relationship between structure and function; and molecular and biochemical mechanisms that may underlie the development of female pelvic floor disorders. Conclusions While the findings of current research will help elucidate the pathophysiologic pathways leading to the development of female pelvic floor disorders, much more research is needed for full understanding that will result in better care for patients through specific rather than empiric therapy, and lead to the potential for prevention on primary and secondary levels. © 2004 Wiley-Liss, Inc. [source]

Spatio-temporal variation in pollen limitation and reproductive success of two scape morphs in Primula farinosa

Didrik Vanhoenacker
Summary ,,In plant populations where reproductive output is limited by pollinator visitation, plants with attractive floral displays should have a selective advantage. We examined the effect of inflorescence height on pollination success in Primula farinosa, which is dimorphic for scape length. ,,To test the hypothesis that fruit and seed initiation are more strongly pollen-limited in the short-scaped than in the long-scaped morph, and that this difference is affected by spatio-temporal variation in pollen limitation, we conducted a hand-pollination experiment in four populations over 2 yr. ,,Pollen limitation of fruit initiation varied among populations and years, and was stronger in the short-scaped than in the long-scaped morph. ,,The results suggest that interactions with pollinators will need to be considered for a full understanding of the maintenance of this striking polymorphism. The study also shows that, although pollen limitation is likely to vary in space and time in many plant species, such variation is not necessarily associated with variation in selection on floral characters. [source]

Ultrastructural Changes in Axons Following Exposure to Pulsed Radiofrequency Fields

PAIN PRACTICE, Issue 6 2009
Serdar Erdine MD
Abstract Pulsed radiofrequency (PRF) fields applied by an electrode to neural structures, such as the peripheral sensory nociceptor axons and dorsal root ganglion, are clinically effective in reducing pain and other neuropathic syndromes. However, a full understanding of the underlying mechanisms by which this occurs has not yet been clarified. In this study, PRF is applied to the afferent axons of the sciatic nerves of rats. A standard radiofrequency (RF) electrode and RF generator is used to apply the RF signal output to the sciatic nerve using standard PRF parameters that have been successfully used in clinical practice. The ultrastructure of the treated axons is observed after 10 days by electron microscopy. A control, sham application is simultaneously applied to the contralateral sciatic nerve to provide a statistical differential comparison. It is found that the internal ultrastructural components of the axons show microscopic damage after PRF exposure, including: abnormal membranes and morphology of mitochondria, and disruption and disorganization of microfilaments and microtubules. The damage appears to be more pronounced for C-fibers than for A-delta and A-beta fibers. The results are discussed in terms of internal electric field strengths and thermodynamic parameters. [source]

The End of the Fertility Transition in the Developed World

John Bongaarts
By the late 1990s the average period total fertility rate in the developed world had declined to 1.6, a level substantially lower than projected in the 1970s and 1980s. This article examines recent trends and patterns in fertility in the developed world with particular emphasis on the effects and implications of changes in the timing of childbearing. The main objective is to demonstrate that while fertility in these countries is indeed low, women's childbearing levels are not as low as period measures such as the total fertility rate suggest. To obtain a full understanding of the various dimensions of fertility change. several indicators are examined, including period and cohort fertility by birth order and childbearing preferences. An analysis of these indicators demonstrates that period fertility measures in many developed countries are temporarily depressed by a rise in the mean age at childbearing. The distortion of the TFR is as great as 0.4 births per woman in Italy and Spain. These effects have been present in many developed countries since the 1970s and could continue for years into the future. But tempo effects are temporary, and once the postponement of childbearing ends,as it eventually must,the corresponding fertility-depressing effect stops, thus putting upward pressure on period fertility. Countries with very low fertility and substantial tempo effects may well experience rises in fertility in the near future if the timing of childbearing stabilizes. Even if this happens, however, it seems unlikely that fertility will rebound to the replacement level. [source]

Heterozygote Carrier Testing in High Schools Abroad: What are the Lessons for the U.S.?

Lainie Friedman Ross M.D., Ph.D.Article first published online: 23 NOV 200
The main value of carrier detection in the general population is to determine reproductive risks. In this manuscript I examine the practice of providing carrier screening programs in the school setting. While the data show that high school screening programs can achieve high uptake, I argue that this may reflect a lack of full understanding about risks, benefits, and alternatives, and the right not to know. It may also reflect the inherent coercion in group testing, particularly for adolescents who are prone to peer pressure. The problem of carrier screening in the schools is compounded when the condition has a predilection for certain groups based on race, ethnicity or religion. I examine programs around the world that seek to test high school students for Tay Sachs and Cystic Fibrosis carrier status. I argue that carrier programs should be designed so as to minimize stigma and to allow individuals to refuse. The mandatory school environment cannot achieve this. Rather, I conclude that screening programs should be designed to attract young adults and not adolescents to participate in a more voluntary venue. [source]

What's behind crashing memories?

Plausibility, belief, memory in reports of having seen non-existent images
The present study investigated the precise nature of crashing memory reports: Are they truly memories or are they based on beliefs? We asked 88 individuals whether they had seen non-existent footage of the Pim Fortuyn assassination and conducted thorough post-experimental interviews. Two-thirds of our participants falsely reported having seen the footage, while less than 10% also reported details that they could not have seen. Moreover, plausibility ratings of having seen the images were higher than false belief ratings, which in turn were higher than false memory ratings. After having been fully debriefed, 81% of the participants who reported crashing memories attributed their false report to their lack of a full understanding of the critical question. Another 10% of this subsample stated that they truly remembered the images (i.e. false memories). Thus, only a small subset of crashing memory reports seems to be induced by false beliefs and/or false memories. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Intrinsic Toxicity of Hemoglobin: How to Counteract It

Jan Simoni
Abstract The development of safe and effective blood substitutes is of great importance in both civilian and military medicine. The currently tested hemoglobin (Hb)-based oxygen carriers, however, have toxicity and efficacy problems. A number of unwanted effects have been observed in human trials, creating doubts about their clinical usefulness. In some subjects, vasoconstriction and decreased blood flow to the vital organs, heart attack, stroke, systemic inflammation, organ damage, and even death, have been attributed to the transfusion of these experimental products. Hb is a well-known pressor agent and strong oxidant, although the full understanding of its intrinsic toxicity is yet to be uncovered. In particular, the complete mechanism of Hb-induced vasoconstriction needs full elucidation. Knowledge of the biological events that trigger the induction of genes upon treatment with redox-active Hb, as well as its catabolism, is still incomplete. It seems that our limited knowledge of free Hb effects in vivo is the main reason for not yet having a viable substitute of human blood. The future for universal red cell substitutes is in the new-generation products that address all of Hb's intrinsic toxicity issues. [source]

Analysis and validation of carbohydrate three-dimensional structures

Thomas Lütteke
Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein,carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein,carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures. [source]

What do they know?: a content analysis of women's perceptions of trial information

Sara Kenyon
Objective To examine interpretations of study information by women participating in ORACLE, a trial of antibiotics in preterm labour. Design Questionnaire survey sent to women recruited to the ORACLE trial. Setting United Kingdom. Population A questionnaire was sent to 3074 ORACLE participants in a purposively selected sample of 55 collaborating maternity units, chosen to reflect a range of regions and of district general and teaching hospitals. Methods Content analysis was applied to verbatim text provided in response to an open question. Responses were also compared with a framework based on key points about the purpose of ORACLE. Closed questions were analysed using descriptive statistics. Main outcome measures Participants' interpretations of the purpose of the study. Results A response rate of 61% was achieved, and 1462 participants provided written answers to a specific question on why the study was being carried out. Content analysis suggested that the information leaflet was highly valued as a source of information about the trial. There was evidence that women's interpretations of the purpose of the trial were not identical to those that the investigators intended. Of the five key points about the trial described in the information leaflet, 400 (27%) participants reported one key point, 550 (38%) two key points, 229 (16%) three key points and 23 (1.5%) four key points. None reported five key points and it was not possible to classify 46 responses (3%). Vague, confused understanding or poor recall were evident in 204 (14%) of responses. Conclusion Although the ORACLE trial was run as a model of good practice at the time, this study suggests that it may not be possible to demonstrate full understanding of trial purpose and design by all participants. Emphasis should be on the provision of full information that involves consumers in its design and evaluation. [source]

Cerebral mechanisms and voiding function

Ranan DasGupta
Some of the most recent work investigating the cerebral mechanisms involved in bladder control has been very helpful in adding to our understanding of bladder dysfunction. The group behind this work, from London, presents a mini-review which will help to update our knowledge in this area. Authors from Australia present a review describing the interactions between bone and prostate cancer cells in metastatic disease. This area has generated much interest and is something for which we should develop a full understanding, to optimise our treatments for this condition. [source]

2414: Laser and vitrectomy

Purpose Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Methods Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Results Retinal photocoagulation has also repeatedly been shown to improve retinal oxygenation. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids Conclusion Vitrectomy and laser retinal treatment both improve oxygenation of the ischemic retina, reduce VEGF formation and thereby reduce neovascularisation and edema. [source]