Home About us Contact
|
Home About us Contact | ||
|
|
||
Several Theories (several + theory)
Selected AbstractsOrigins of a stereotype: categorization of facial attractiveness by 6-month-old infantsDEVELOPMENTAL SCIENCE, Issue 2 2004Jennifer L. Ramsey Like adults, young infants prefer attractive to unattractive faces (e.g. Langlois, Roggman, Casey, Ritter, Rieser-Danner & Jenkins, 1987; Slater, von der Schulenburg, Brown, Badenoch, Butterworth, Parsons & Samuels, 1998). Older children and adults stereotype based on facial attractiveness (Eagly, Ashmore, Makhijani & Longo, 1991; Langlois, Kalakanis, Rubenstein, Larson, Hallam & Smooth, 2000). How do preferences for attractive faces develop into stereotypes? Several theories of stereotyping posit that categorization of groups is necessary before positive and negative traits can become linked to the groups (e.g. Tajfel, Billig, Bundy & Flament, 1971; Zebrowitz-McArthur, 1982). We investigated whether or not 6-month-old infants can categorize faces as attractive or unattractive. In Experiment 1, we familiarized infants to unattractive female faces; in Experiment 2, we familiarized infants to attractive female faces and tested both groups of infants on novel faces from the familiar or novel attractiveness category. Results showed that 6-month-olds categorized attractive and unattractive female faces into two different groups of faces. Experiments 3 and 4 confirmed that infants could discriminate among the faces used in Experiments 1 and 2, and therefore categorized the faces based on their similarities in attractiveness rather than because they could not differentiate among the faces. These findings suggest that categorization of facial attractiveness may underlie the development of the ,beauty is good' stereotype. [source] Varicocelectomy reduces reactive oxygen species levels and increases antioxidant activity of seminal plasma from infertile men with varicoceleINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2001T. Mostafa Several theories have been advanced to explain the mechanisms by which varicocele impairs male fertility. These theories include scrotal hyperthermia, retrograde flow of adrenal or renal metabolites, Leydig cell dysfunction and hypoxia. Varicocele is reported to be associated with elevated reactive oxygen species (ROS) production in spermatozoa and diminished seminal plasma antioxidant activity. The aim of this study was to investigate whether surgical correction of varicocele might reduce ROS or increase the antioxidant capacity of seminal plasma from infertile patients with varicocele. The study group consisted of 68 infertile males, selected from patients scheduled for varicocelectomy at Cairo University Hospital during the year 1999. Seminal plasma levels of two ROS [malondialdehyde (MDA), hydrogen peroxide (H2O2)] and one ROS radical [nitric oxide (NO)] were estimated as well as six antioxidants [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), vitamin C (Vit C), vitamin E (Vit E), albumin) on the day prior to varicocelectomy. For comparison, the same parameters were measured again 3 and 6 months post-operatively. A statistically significant reduction in the 3 month post-operative levels of MDA, H2O2 and NO was observed when compared with the pre-operative values. A further significant reduction took place during the following 3 months. Four of the six antioxidants tested (SOD, CAT, GPx, and Vit C) showed a significant increase in seminal levels when comparing 3-month post-operative with pre-operative values. A further significant increase of the four antioxidant levels took place during the following 3 months. No significant change in the level of seminal plasma albumen took place during the first 3 months after varicocelectomy, however, a significant increase was noted during the next 3 months. In contrast to other antioxidants, seminal plasma levels of Vit E showed a significant decrease when comparing 3-month post-operative with pre-operative values. A further significant decrease took place during the following 3 months. It is concluded that varicocelectomy reduces ROS levels and increases antioxidant activity of seminal plasma from infertile men with varicocele. [source] Ethnicity and Shared Meanings: A Case Study of the "Orphaned Bones" Ritual in Mainland China and OverseasAMERICAN ANTHROPOLOGIST, Issue 4 2009Bernard Formoso ABSTRACT Several theories of ethnicity emphasize the analysis of intergroup relations. They neglect, however, the conflation of ideas and values structuring these relations,notably the cross-cultural aggregates of shared cultural meanings that underlie forms of cooperation and competition between interacting groups. In this article, I explore this kind of process through a multisite ethnography of the Xiu gugu ("refining of orphaned bones"), a ritual that the Chaozhou people of northeast Guangdong province, an ethnic subgroup of the Han, perform periodically. The celebration of this rite in Chaozhou is compared to versions resulting of the ritual in Malay Muslim and Thai Buddhist contexts. In the latter case, close conceptions of malevolent death underlie a fascinating interethnic cooperation, with most of the unfortunate dead whose bones are "refined" during the Chaozhou ritual being Thai. [source] Hypereosinophilia associated with cardiac rhabdomyosarcomaAMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2003Vincent Lo Re III Abstract Hypereosinophilia, defined as an absolute eosinophil count exceeding 1,500/mm3, is caused by a limited number of disorders. Its association with malignancy is a rare occurrence that typically denotes extensive metastasis and a poor prognosis. Several theories have been proposed to explain the hypereosinophilia associated with malignancy, focusing on the production of eosinophilopoietic cytokines by tumors. We describe a patient with hypereosinophilia associated with a cardiac rhabdomyosarcoma, review the etiologies of hypereosinophilia, and discuss the possible mechanisms. Am. J. Hematol. 74:64,67, 2003. © 2003 Wiley-Liss, Inc. [source] Role of Postcircumcision Mucosal Cuff Length in Lifelong Premature Ejaculation: A Pilot StudyTHE JOURNAL OF SEXUAL MEDICINE, Issue 1 2008Seyed Reza Hosseini MD ABSTRACT Introduction., Premature ejaculation (PE) is the most prevalent sexual dysfunction among men. Several theories about its etiology have been made. One of the conflicting factors is the effect of circumcision on ejaculation, and there are some concerns about leaving so much mucosa during circumcision. Aim., In our study the relationship between mucosal cuff length and PE was investigated. Methods., Eighty-four circumcised men were studied, including 42 men with PE and 42 men without. The following data and measurements were investigated: age, education, smoking, intravaginal ejaculation latency time (IELT), circumcision timing, stretched penile, penile skin, and mucosal cuff lengths. Main Outcome Measure., Penile, mucosal cuff, and penile skin lengths, the IELT. Results., The mean penile, mucosal cuff, and penile skin lengths were 121.1 ± 12.8, 15.4 ± 4.8, and 80.8 ± 21.0 mm in PE men, respectively, and were 130.1 ± 10.4, 14.7 ± 3.4, and 88.7 ± 12.2 mm in the control group, respectively. No statistically significant differences were seen regarding the length of the penis (P = 0.80), mucosal cuff (P = 0.84), and penile skin (P = 0.99). The two groups were not different regarding education (P = 0.90), smoking (P = 0.70), and circumcision timing (P = 0.65). Conclusion., Postcircumcision mucosal cuff length is not a risk factor for PE. Hosseini SR, Khazaeli MH, and Atharikia D. Role of postcircumcision mucosal cuff length in lifelong premature ejaculation: A pilot study. J Sex Med 2008;5:206,209. [source] Coincidence, coevolution, or causation?BIOLOGICAL REVIEWS, Issue 1 2001DNA content, cellsize, the C-value enigma ABSTRACT Variation in DNA content has been largely ignored as a factor in evolution, particularly following the advent of sequence-based approaches to genomic analysis. The significant genome size diversity among organisms (more than 200000-fold among eukaryotes) bears no relationship to organismal complexity and both the origins and reasons for the clearly non-random distribution of this variation remain unclear. Several theories have been proposed to explain this ,C-value enigma' (heretofore known as the ,C-value paradox'), each of which can be described as either a ,mutation pressure' or ,optimal DNA' theory. Mutation pressure theories consider the large portion of non-coding DNA in eukaryotic genomes as either ,junk' or ,selfish' DNA and are important primarily in considerations of the origin of secondary DNA. Optimal DNA theories differ from mutation pressure theories by emphasizing the strong link between DNA content and cell and nuclear volumes. While mutation pressure theories generally explain this association with cell size as coincidental, the nucleoskeletal theory proposes a coevolutionary interaction between nuclear and cell volume, with DNA content adjusted adaptively following shifts in cell size. Each of these approaches to the C-value enigma is problematic for a variety of reasons and the preponderance of the available evidence instead favours the nucleotypic theory which postulates a causal link between bulk DNA amount and cell volume. Under this view, variation in DNA content is under direct selection via its impacts on cellular and organismal parameters. Until now, no satisfactory mechanism has been presented to explain this nucleotypic effect. However, recent advances in the study of cell cycle regulation suggest a possible ,gene-nucleus interaction model' which may account for it. The present article provides a detailed review of the debate surrounding the C-value enigma, the various theories proposed to explain it, and the evidence in favour of a causal connection between DNA content and cell size. In addition, a new model of nucleotypic influence is developed, along with suggestions for further empirical investigation. Finally, some evolutionary implications of genome size diversity are considered, and a broadening of the traditional ,biological hierarchy' is recommended. [source] Obsessive-Compulsive Disorder in Children and AdolescentsCHILD AND ADOLESCENT MENTAL HEALTH, Issue 2 2001Roz Shafran Obsessive-compulsive disorder (OCD) is estimated to affect between 0.5% and 2% of children and adolescents. The majority of clinical cases has both obsessions and compulsions. Depression, anxiety and tic disorders are common comorbid diagnoses, and assessment can therefore be complex. Several theories have been proposed for the aetiology and maintenance of the disorder, including cognitive-behavioural and neuropsychiatric theories. Cognitive-behavioural and pharmacological treatments are both probably efficacious therapies for children and adolescents but further research is needed to compare these treatments with each other, and to examine the use of combination therapies in controlled trials. [source] Update on Atrial Fibrillation: Part ICLINICAL CARDIOLOGY, Issue 2 2008Irina Savelieva M.D. Abstract Atrial fibrillation (AF) is an epidemic, affecting 1% to 1.5% of the population in the developed world. Projected data from the population-based studies suggest that the prevalence of AF will grow at least 3-fold by 2050. The health and economic burden imposed by AF and AF-related morbidity is enormous. Atrial fibrillation has a multiplicity of causes ranging from genetic to degenerative, but hypertension and heart failure are the commonest and epidemiologically most prevalent conditions associated with AF as both have been shown to create an arrhythmogenic substrate. Several theories emerged regarding the mechanism of AF, which can be combined into two groups: the single focus hypothesis and the multiple sources hypothesis. Several lines of evidence point to the relevance of both hypotheses to the mechanism of AF, probably with a different degree of involvement depending on the variety of AF (paroxysmal or persistent). Sustained AF alters electrophysiological and structural properties of the atrial myocardium such that the atria become more susceptible to the initiation and maintenance of the arrhythmia, a process known as atrial remodeling. Angiotensin II has been recognized as a key element in atrial remodeling in association with AF opening the possibility of exploitation of "upstream" therapies to prevent or delay atrial remodeling. The clinical significance of AF lies predominantly in a 5-fold increased risk of stroke. The limitations of warfarin prompted the development of new antithrombotic drugs, which include anticoagulants, such as direct oral thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban, apixaban). Novel mechanical approaches for the prevention of cardioembolic stroke have recently been evaluated: percutaneous left atrial appendage occluders, minimally invasive surgical isolation of the left atrial appendage, and implantation of carotid filtering devices. Copyright © 2008 Wiley Periodicals, Inc. [source] Goldenhar syndrome and neuroblastoma: a chance association?ACTA PAEDIATRICA, Issue 10 2003C Michel-Adde Oculoauriculovertebral dysplasia, also called Goldenhar syndrome, includes several anomalies: epibulbar dermoids or lipodermoids, microtia, mandibular hypoplasia, vertebral, skeletal, cardiac and kidney anomalies, among others. Tumours have also been observed in patients with oculoauriculovertebral dysplasia. We report the first case of oculoauriculovertebral dysplasia associated with a neuroblastoma. This tumour consists of cells identical to early migratory neural crest cells in the embryo. Several theories have been proposed regarding the pathogenetic explanation of oculoauriculovertebral dysplasia. Currently, some researchers have suggested a deficiency in mesodermal formation or defective interaction between neural crest and mesoderm as a possible aetiology. Conclusion: It is suggested that the case reported here is an additional argument for an anomaly in neural crest cell migration or interaction with the mesoderm in the pathogenesis of oculoauriculovertebral dysplasia. [source] REVIEW: Reward sensitivity: issues of measurement, and achieving consilience between human and animal phenotypesADDICTION BIOLOGY, Issue 2 2010David N. Stephens ABSTRACT Reward is a concept fundamental to discussions of drug abuse and addiction. The idea that altered sensitivity to either drug,reward, or to rewards in general, contributes to, or results from, drug-taking is a common theme in several theories of addiction. However, the concept of reward is problematic in that it is used to refer to apparently different behavioural phenomena, and even to diverse neurobiological processes (reward pathways). Whether these different phenomena are different behavioural expressions of a common underlying process is not established, and much research suggests that there may be only loose relationships among different aspects of reward. Measures of rewarding effects of drugs in humans often depend upon subjective reports. In animal studies, such insights are not available, and behavioural measures must be relied upon to infer rewarding effects of drugs or other events. In such animal studies, but also in many human methods established to objectify measures of reward, many other factors contribute to the behaviour being studied. For that reason, studying the biological (including genetic) bases of performance of tasks that ostensibly measure reward cannot provide unequivocal answers. The current overview outlines the strengths and weaknesses of current approaches that hinder the conciliation of cross-species studies of the genetics of reward sensitivity and the dysregulation of reward processes by drugs of abuse. Some suggestions are made as to how human and animal studies may be made to address more closely homologous behaviours, even if those processes are only partly able to isolate ,reward' from other factors contributing to behavioural output. [source] Role of GSK-3, activity in motor neuronal cell death induced by G93A or A4V mutant hSOD1 geneEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2005Seong-Ho Koh Abstract Point mutations such as G93A and A4V in the human Cu/Zn-superoxide dismutase gene (hSOD1) cause familial amyotrophic lateral sclerosis (fALS). In spite of several theories to explain the pathogenic mechanisms, the mechanism remains largely unclear. Increased activity of glycogen synthase kinase-3 (GSK-3) has recently been emphasized as an important pathogenic mechanism of neurodegenerative diseases, including Alzheimer's disease and ALS. To investigate the effects of G93A or A4V mutations on the phosphatidylinositol-3-kinase (PI3-K)/Akt and GSK-3 pathway as well as the caspase-3 pathway, VSC4.1 motoneuron cells were transfected with G93A- or A4V-mutant types of hSOD1 (G93A and A4V cells, respectively) and, 24 h after neuronal differentiation, their viability and intracellular signals, including PI3-K/Akt, GSK-3, heat shock transcription factor-1 (HSTF-1), cytochrome c, caspase-3 and poly(ADP-ribose) polymerase (PARP), were compared with those of wild type (wild cells). Furthermore, to elucidate the role of the GSK-3,-mediated cell death mechanism, alterations of viability and intracellular signals in those mutant motoneurons were investigated after treating the cells with GSK-3, inhibitor. Compared with wild cells, viability was greatly reduced in the G93A and A4V cells. However, the treatment of G93A and A4V cells with GSK-3, inhibitor increased their viability by activating HSTF-1 and by reducing cytochrome c release, caspase-3 activation and PARP cleavage. However, the treatment did not affect the expression of PI3-K/Akt and GSK-3,. These results suggest that the G93A or A4V mutations inhibit PI3-K/Akt and activate GSK-3, and caspase-3, thus becoming vulnerable to oxidative stress, and that the GSK-3,-mediated cell death mechanism is important in G93A and A4V cell death. [source] Competition in variable environments: experiments with planktonic rotifersFRESHWATER BIOLOGY, Issue 6 2002KEVIN L. KIRK 1.,In a constant environment, competition often tends to reduce species diversity. However, several theories predict that temporal variation in the environment can slow competitive exclusion and allow competing species to coexist. This study reports on laboratory competition experiments in which two pairs of planktonic rotifer species competed for a phytoplankton resource under different conditions of temporal variability in resource supply. 2.,For both species pairs, Keratella cochlearis dominated under all conditions of temporal variability, and the other species (Brachionus calyciflorus or Synchaeta sp.) almost always went extinct. Increasing temporal variation in resource supply slowed competitive exclusion but did not change competitive outcome or allow coexistence. 3.,Rotifers show a gleaner,opportunist trade-off, because gleaner species have low threshold resource levels (R*) and low maximum population growth rates, while opportunist species have the opposite characteristics. In the competition experiments, the gleaner always won and the opportunists always lost. Thus, a gleaner,opportunist trade-off was not sufficient to facilitate coexistence under conditions of resource variability. Instead, the winning species had both the lowest R* and the greatest ability to store resources and ration their use during times of extreme resource scarcity. [source] Classical and advanced multilayered plate elements based upon PVD and RMVT.INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2002Part 2: Numerical implementations Abstract This paper presents numerical evaluations related to the multilayered plate elements which were proposed in the companion paper (Part 1). Two-dimensional modellings with linear and higher-order (up to fourth order) expansion in the z -plate/layer thickness direction have been implemented for both displacements and transverse stresses. Layer-wise as well as equivalent single-layer modellings are considered on both frameworks of the principle of virtual displacements and Reissner mixed variational theorem. Such a variety has led to the implementation of 22 plate theories. As far as finite element approximation is concerned, three quadrilaters have been considered (four-, eight- and nine-noded plate elements). As a result, 22×3 different finite plate elements have been compared in the present analysis. The automatic procedure described in Part 1, which made extensive use of indicial notations, has herein been referred to in the considered computer implementations. An assessment has been made as far as convergence rates, numerical integrations and comparison to correspondent closed-form solutions are concerned. Extensive comparison to early and recently available results has been made for sample problems related to laminated and sandwich structures. Classical formulations, full mixed, hybrid, as well as three-dimensional solutions have been considered in such a comparison. Numerical substantiation of the importance of the fulfilment of zig-zag effects and interlaminar equilibria is given. The superiority of RMVT formulated finite elements over those related to PVD has been concluded. Two test cases are proposed as ,desk-beds' to establish the accuracy of the several theories. Results related to all the developed theories are presented for the first test case. The second test case, which is related to sandwich plates, restricts the comparison to the most significant implemented finite elements. It is proposed to refer to these test cases to establish the accuracy of existing or new higher-order, refined or improved finite elements for multilayered plate analyses. Copyright © 2002 John Wiley & Sons, Ltd. [source] Arriving at a strategic theory of the firmINTERNATIONAL JOURNAL OF MANAGEMENT REVIEWS, Issue 4 2000Steven E. Phelan The theory of the firm seeks to explain the existence and boundaries of the firm in relation to the market. Since the pioneering work of Coase (The nature of the firm. Economica, 4, 386,405, 1937), economics has developed a whole family of theories that focus on the ability of firms to economize on certain costs of using markets. More recently, researchers in strategic management have published several theories of the firm that have tended to emphasize the benefits of incorporation rather than the costs of using the market. Although researchers in the strategy profession have tentatively labeled their work as ,moving towards' a strategic theory of the firm, economists have been very critical of existing approaches. This paper seeks to begin ,arriving' at a strategic theory of the firm by addressing these criticisms and offering an integration of the strategic and economic perspectives within an institutional framework. The paper concludes with future directions for research in the theory of the firm. [source] Globalization and Prison Privatization: Why Are Most of the World's For-Profit Adult Prisons to Be Found in the American South?INTERNATIONAL POLITICAL SOCIOLOGY, Issue 3 2007Phillip J. Wood For a generation, students of comparative public policy and international politics have argued that global market discipline and the increasing mobility of international "best practices" have given rise to policy convergence at the global level. This paper uses the American case to investigate some of the forces thought to have given rise to the spread of private prisons. It finds that while there are prisons in a number of countries, the evidence of convergence is thin and seems to suggest that the core of the prison privatization is in the American South. It then examines several theories,the political economy of the prison boom and overcrowding, globalization theory, the politics of the new right and the idea of a "prison-industrial complex",that have been used to explain prison privatization and the extent to which they are consistent with the empirical pattern. Each takes us some way to understanding that pattern, but none can provide a clear theoretical mapping. [source] Satellite species in lampreys: a worldwide trend for ecological speciation in sympatry?JOURNAL OF FISH BIOLOGY, Issue 2 2003V. Salewski Amongst several theories of speciation, sympatric speciation has been the most controversial but it is now widely accepted that populations can become reproductively isolated without being separated geographically. One problem with the acceptance of the theory of sympatric speciation, however, has been the lack of supporting empirical data and it is still believed that geographical isolation is responsible for the majority of speciation events. Here the example of species pairs in lampreys suggests that sympatric speciation in a whole taxonomic group could occur throughout its worldwide range. Lampreys occur in two ecologically distinct forms: parasitic mostly anadromous species that forage on tissue and body fluids of host fishes, and non-parasitic forms that, apart from a short adult life when they cease feeding, spend their entire life as filter feeders in the substratum of stream beds. Both forms occur in sympatric species pairs throughout the range of lampreys that occur in Eurasia, North America and Australia and it is widely acknowledged that non-parasitic forms derive from parasitic forms. The larvae of both forms can be distinguished by their potential fecundity and therefore, it is argued that the mode of life is not a consequence of different ecological conditions. Furthermore, as lampreys prefer to choose mates of similar sizes and fertilization success decreases with increasing difference in body size, there is a strong disruptive selection between the two forms and they are therefore reproductively isolated. Besides theoretical aspects, the similarity of the species pairs, together with their occurrence in sympatry, the occurrence of forms with intermediate characteristics, and examples where speciation might be in progress, hints at the possibility that speciation also occurred in sympatry. The difference between lampreys and other examples of sympatric speciation is that there seems to be a trend towards sympatric speciation events throughout the worldwide range of lampreys which is neither restricted to relatively small localities nor caused by human disturbance. Species pairs in lampreys therefore offer a unique possibility of studying the process of sympatric speciation on a large scale. [source] Rival research programmes and their influence on nursing practiceJOURNAL OF NURSING MANAGEMENT, Issue 2 2004David Newbold BSc In most forms of industry, there is an explicit link between research and development and subsequent technological processes. New discoveries can alter the direction or trajectory of technological progress. In this respect, health care is no different to any other form of industry. There are several theories of science which attempt to explain this link and predict its behaviour. According to Lakatos (1978), rival research programmes may co-exist, whilst Brouwer (1990) suggests they may vie with each other to alter the direction of technological progress. Presently, there are at least two research programmes which are competing to capture the activities of nurses. These are: the Health Care as Industrial Process programme, generating guideline driven nursing, and use of care pathways to maximize throughput plus labour substitution to minimize costs; and the Health Care as Therapeutic Interaction programme, focused on the management and delivery of the fundamental aspects of nursing care, and the use of emotional labour and psychological care to enable patients to cope and make sense of their situation. Ideally, the direction of practice should reflect both of these valid research programmes, with nurses as the staff best placed to integrate medical technology with humanity. Arguably, it is the Industrial Process programme which is currently dominant, at the price of decreased quality of care, and loss of the health benefits of therapeutic interaction. Greater effort is needed, in terms of research to reduce the apparent ,invisibility' of emotional labour, and education of nurses to boost therapeutic interaction skills. In order to re-direct the trajectory, managers should acknowledge and accommodate aspects of therapeutic interaction in service re-engineering, and use quality assurance tools which may accurately detect and monitor therapeutic interaction by nurses. [source] Understanding the Search for Meaning in Life: Personality, Cognitive Style, and the Dynamic Between Seeking and Experiencing MeaningJOURNAL OF PERSONALITY, Issue 2 2008Michael F. Steger ABSTRACT Although several theories assert that understanding the search for meaning in life is important, empirical research on this construct is sparse. Three studies provide the first extensive effort to understand the correlates of the search for meaning in a multistudy research program. Assessed were relations between search for meaning and well-being, cognitive style, and the Big Five, Big Three, Approach/Avoidance, and Interest models of personality, with a particular emphasis on understanding the correlates of search for meaning that are independent of presence of meaning. Conceptual models of the relation between search and presence were tested. Findings suggest that people lacking meaning search for it; the search for meaning did not appear to lead to its presence. Study 3 found that basic motive dispositions moderated relations between search for meaning and its presence. Results highlight the importance of basic personality dispositions in understanding the search for meaning and its correlates. [source] Taking Others into Account: Self-Interest and Fairness in Majority Decision MakingAMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2010Jan Sauermann Research on the formal properties of democratic aggregation mechanisms has a long tradition in political science. Recent theoretical developments, however, show that in the discussion of normative contents of democratic decisions, the actual shape of preferences deserves just as much attention. However, our knowledge about the concrete motivations of individual behavior in democratic decisions is incomplete. Using laboratory experiments, this article examines the existence of social preferences in majority decisions. Contrary to earlier experiments of committee decision making, we develop a design that controls for the conditions of communication and the level of information between subjects. This allows us to comparatively test the predictive power of several theories. We find strong evidence that self-interest and fairness motivate human behavior in majority decisions. [source] Factors Influencing Housing Equity Withdrawal: Evidence from a Microeconomic Survey,THE ECONOMIC RECORD, Issue 267 2008CARL SCHWARTZ The increase in housing equity withdrawal and coincident decline in aggregate savings rates in a number of countries in recent years is consistent with the consumption-smoothing model of housing equity withdrawal. However, there are a variety of other theoretical models that purport to explain why households withdraw and inject equity. To assess the relative importance of these various theories, we use a comprehensive survey of the equity withdrawal and injection decisions of Australian households. We find support for several theories. Life cycle considerations appear to be most important, with older households accounting for the bulk of equity withdrawn. Portfolio rebalancing considerations also appear important, with financial asset accumulation the primary use of withdrawn funds. Consumption-smoothing motives play an influential role, although primarily for smaller-value transactions. [source] Antioxidants reduce diabetic damage in bovine lenses in cultureACTA OPHTHALMOLOGICA, Issue 2009A DOVRAT Purpose Background: There are several theories regarding possible mechanisms leading to diabetic cataract. Few of them include oxidation stress. Aims: Investigation of the mechanisms of cataract formation under diabetic conditions, and examination of the effects of N-acetyl-L-cysteine (NAC), (which is a precursor of glutathione and an anti-inflammatory agent) and derivatives of Desferrioxamine (DFO)(which is an iron chelator and reduces oxidative stress) on diabetic cataract. Methods The experiments included 78 bovine lenses. The lenses were divided into eight different treatments including controls and lenses incubated with high glucose levels (450 mg %) with or without each one of the antioxidants. The intact lenses were incubated for a period of two weeks in our special organ culture conditions. Lens optical quality was analyzed every 24 hours. At the end of the culture period, oxidation was followed in the lens epithelial cells with dichlorofluorescein assay and lens proteins were analyzed by SDS and 2D gel electrophoresis. Results High levels of glucose in the culture medium caused optical damage to bovine lenses, increased lens volume due to swelling, increased oxidation of lens epithelial cells, and caused changes in lens beta crystallin. The anti-oxidants reduced this damage. NAC and Zn-DFO protected the lenses better than DFO. Conclusion Antioxidants can protect the lens from high glucose damage. This study was supported in part by a grant from the Esther and Chaim Coppel Trust and by the Guzik Ophthalmology Research Fund [source] | |||||||||||||||||||||||||