Why bayesian “evidence for H1” in one condition and bayesian “evidence for H0” in another condition does not mean good-enough bayesian evidence for a difference between the conditions

Psychologists are often interested in whether an independent variable has a different effect in condition A than in condition B. To test such a question, one needs to directly compare the effect of that variable in the two conditions (i.e., test the interaction). Yet many researchers tend to stop when they find a significant test in one condition and a nonsignificant test in the other condition, deeming this as sufficient evidence for a difference between the two conditions. In this Tutorial, we aim to raise awareness of this inferential mistake when Bayes factors are used with conventional cutoffs to draw conclusions. For instance, some researchers might falsely conclude that there must be good-enough evidence for the interaction if they find good-enough Bayesian evidence for the alternative hypothesis, H1, in condition A and good-enough Bayesian evidence for the null hypothesis, H0, in condition B. The case study we introduce highlights that ignoring the test of the interaction can lead to unjustified conclusions and demonstrates that the principle that any assertion about the existence of an interaction necessitates the direct comparison of the conditions is as true for Bayesian as it is for frequentist statistics. We provide an R script of the analyses of the case study and a Shiny app that can be used with a 2 × 2 design to develop intuitions on this issue, and we introduce a rule of thumb with which one can estimate the sample size one might need to have a well-powered design

Factors Influencing Real Estate Brokerage Sales Staff Performance

This research examined factors that affect residential real estate sales staff performance from sixteen firms of various sizes in different residential markets. The human capital model was related to sales staff commission earnings. A psychological factors model and management systems model were introduced that explained variance beyond that accounted for by the human capital model. Multiple regression analysis demonstrated that five of the twenty-seven variables examined accounted for most of the statistically significant variance. These variables included gender, hours worked per week, amount of formal education, work satisfaction, and reputation of the firm. Suggestions on how to utilize the findings regarding those variables related to earnings, as well as those not related, are briefly discussed.

Setting Priorities for Space Research: Opportunities and Imperatives

This report represents the first phase of a study by a task group convened by the Space Studies Board to ascertain whether it should attempt to develop a methodology for recommending priorities among the various initiatives in space research (that is, scientific activities concerned with phenomena in space or utilizing observations from space). The report argues that such priority statements by the space research community are both necessary and desirable and would contribute to the formulation and implementation of public policy. The report advocates the establishment of priorities to enhance effective management of the nation's scientific research program in space. It argues that scientific objectives and purposes should determine how and under what circumstances scientific research should be done. The report does not take a position on the controversy between advocates of manned space exploration and those who favor the exclusive use of unmanned space vehicles. Nor does the report address questions about the value or appropriateness of Space Station Freedom or proposals to establish a permanent manned Moon base or to undertake a manned mission to Mars. These issues lie beyond the charge to the task group

Serum clara cell protein: a sensitive biomarker of increased lung epithelium permeability caused by ambient ozone.

Ozone in ambient air may cause various effects on human health, including decreased lung function, asthma exacerbation, and even premature mortality. These effects have been evidenced using various clinical indicators that, although sensitive, do not specifically evaluate the O(3)-increased lung epithelium permeability. In the present study, we assessed the acute effects of ambient O(3) on the pulmonary epithelium by a new approach relying on the assay in serum of the lung-specific Clara cell protein (CC16 or CC10). We applied this test to cyclists who exercised for 2 hr during episodes of photochemical smog and found that O(3) induces an early leakage of lung Clara cell protein. The protein levels increased significantly into the serum from exposure levels as low as 0.060-0.084 ppm. Our findings, confirmed in mice exposed to the current U.S. National Ambient Air Quality Standards for O(3) (0.08 ppm for 8 hr) indicate that above the present natural background levels, there is almost no safety margin for the effects of ambient O(3) on airway permeability. The assay of CC16 in the serum represents a new sensitive noninvasive test allowing the detection of early effects of ambient O(3) on the lung epithelial barrier

Individualization as driving force of clustering phenomena in humans

One of the most intriguing dynamics in biological systems is the emergence of clustering, the self-organization into separated agglomerations of individuals. Several theories have been developed to explain clustering in, for instance, multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of fish, and animal herds. A persistent puzzle, however, is clustering of opinions in human populations. The puzzle is particularly pressing if opinions vary continuously, such as the degree to which citizens are in favor of or against a vaccination program. Existing opinion formation models suggest that "monoculture" is unavoidable in the long run, unless subsets of the population are perfectly separated from each other. Yet, social diversity is a robust empirical phenomenon, although perfect separation is hardly possible in an increasingly connected world. Considering randomness did not overcome the theoretical shortcomings so far. Small perturbations of individual opinions trigger social influence cascades that inevitably lead to monoculture, while larger noise disrupts opinion clusters and results in rampant individualism without any social structure. Our solution of the puzzle builds on recent empirical research, combining the integrative tendencies of social influence with the disintegrative effects of individualization. A key element of the new computational model is an adaptive kind of noise. We conduct simulation experiments to demonstrate that with this kind of noise, a third phase besides individualism and monoculture becomes possible, characterized by the formation of metastable clusters with diversity between and consensus within clusters. When clusters are small, individualization tendencies are too weak to prohibit a fusion of clusters. When clusters grow too large, however, individualization increases in strength, which promotes their splitting.Comment: 12 pages, 4 figure

Humanized Mouse Model of Ovarian Cancer Recapitulates Patient Solid Tumor Progression, Ascites Formation, and Metastasis

Ovarian cancer is the most common cause of death from gynecological cancer. Understanding the biology of this disease, particularly how tumor-associated lymphocytes and fibroblasts contribute to the progression and metastasis of the tumor, has been impeded by the lack of a suitable tumor xenograft model. We report a simple and reproducible system in which the tumor and tumor stroma are successfully engrafted into NOD-scid IL2Rγnull (NSG) mice. This is achieved by injecting tumor cell aggregates derived from fresh ovarian tumor biopsy tissues (including tumor cells, and tumor-associated lymphocytes and fibroblasts) i.p. into NSG mice. Tumor progression in these mice closely parallels many of the events that are observed in ovarian cancer patients. Tumors establish in the omentum, ovaries, liver, spleen, uterus, and pancreas. Tumor growth is initially very slow and progressive within the peritoneal cavity with an ultimate development of tumor ascites, spontaneous metastasis to the lung, increasing serum and ascites levels of CA125, and the retention of tumor-associated human fibroblasts and lymphocytes that remain functional and responsive to cytokines for prolonged periods. With this model one will be able to determine how fibroblasts and lymphocytes within the tumor microenvironment may contribute to tumor growth and metastasis, and will make it possible to evaluate the efficacy of therapies that are designed to target these cells in the tumor stroma

No evidence of association between genetic variants of the PDCD1 ligands and SLE

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldPDCD1, an immunoreceptor involved in peripheral tolerance has previously been shown to be genetically associated with systemic lupus erythematosus (SLE). PDCD1 has two ligands whose genes are located in close proximity on chromosome 9p24. Our attention was drawn to these ligands after finding suggestive linkage to a marker (gata62f03, Z=2.27) located close to their genes in a genome scan of Icelandic families multiplex for SLE. Here, we analyse Swedish trios (N=149) for 23 single nucleotide polymorphisms (SNPs) within the genes of the PDCD1 ligands. Initially, indication of association to eight SNPs was observed, and these SNPs were therefore also analysed in Mexican trios (N=90), as well as independent sets of patients and controls from Sweden (152 patients, 448 controls) and Argentina (288 patients, 288 controls). We do not find support for genetic association to SLE. This is the first genetic study of SLE and the PDCD1 ligands and the lack of association in several cohorts implies that these genes are not major risk factors for SLE.Genes and Immunity (2007) 8, 69-74. doi:10.1038/sj.gene.6364360; published online 30 November 2006

Physics, Topology, Logic and Computation: A Rosetta Stone

In physics, Feynman diagrams are used to reason about quantum processes. In the 1980s, it became clear that underlying these diagrams is a powerful analogy between quantum physics and topology: namely, a linear operator behaves very much like a "cobordism". Similar diagrams can be used to reason about logic, where they represent proofs, and computation, where they represent programs. With the rise of interest in quantum cryptography and quantum computation, it became clear that there is extensive network of analogies between physics, topology, logic and computation. In this expository paper, we make some of these analogies precise using the concept of "closed symmetric monoidal category". We assume no prior knowledge of category theory, proof theory or computer science.Comment: 73 pages, 8 encapsulated postscript figure

Evidence of the validity and accuracy of the Brazilian social attitude of students scale towards politics

Objetivou-se apresentar as evidências de validade e confiabilidade de uma escala brasileira para medir atitudes políticas de estudantes brasileiros de nível superior ante seus comportamentos políticos. O estudo teve uma amostra de abrangência nacional (N = 445), com estudantes brasileiros oriundos de distintos estados. Os resultados indicaram uma estrutura empírica sustentável (teste de Kaiser-Meyer-Olkin - KMO = 0,81), com indicadores psicométricos considerados adequados à mensuração das atitudes políticas. Três fatores empíricos foram identificados: grau de conhecimento sobre política (15 itens, cargas fatoriais entre 0,31 e 0,82, alfa = 0,82, eigenvalue = 5,07 e variância explicada = 18,78 %), afetos relativos à política (7 itens, cargas fatoriais entre 0,41 e 0,58, alfa = 0,72, eigenvalue = 3,17 e variância explicada = 11,73 %) e intenções de comportamento político (2 itens, cargas fatoriais entre 0,70 e 0,72, alfa = 0,80, eigenvalue = 1,8 e variância explicada = 6,8 %). Conclui-se que os resultados fortalecem a estrutura fatorial original da escala e mostram sua utilidade para a identificação de atitudes sociais ante comportamentos políticos.El objetivo de la presente investigación fue presentar las pruebas de confiabilidad y validez de una escala brasileña para medir las actitudes políticas de los estudiantes universitarios brasileños ante su comportamiento político. El estudio contó con una muestra nacional (N = 445) de estudiantes brasileños de diferentes Estados. Los resultados indicaron una estructura empírica sustentable (KMO = .81), con indicadores psicométricos que se consideran adecuados para la medición de las actitudes políticas. Específicamente, se identificaron tres factores empíricos: nivel de conocimiento sobre la política (15 ítems, cargas factoriales entre .31 y .82, alfa = .82, eigenvalue = 5.07 y varianza explicada = 18.78 %), sentimientos acerca de la política (7 ítems, factoriales de .41 y .58, alfa = .72, eigenvalue = 3.17 y varianza explicada = 11.73 °/o) e intenciones del comportamiento político (2 ítems, factoriales de .70 y .72, alfa = .80, eigenvalue = 1.8 y varianza explicada = 6.8 %). Se llegó a la conclusión de que los resultados apoyan la estructura factorial original de la escala y muestran su utilidad en la identificación de las actitudes sociales ante la conducta política.The objective of this study was to present the validity and reliability evidences of a Brazilian scale to measure the political attitudes of Brazilian higher education students regarding their political behavior. The study had a nationwide sample (N = 445), with Brazilian students from different states. The results indicated a sustainable empirical structure (KMO = 0.81), with psychometric indicators considered adequate to the measurement of political attitudes. Three empirical factors were identified: degree of political knowledge (15 items, factorial loads between 0.31 and 0.82, alpha = 0.82, eigenvalue = 5.07 and explained variance = 18.78%), feelings about politics (7 items, factorial loads between 0.41 and 0.58, alpha = 0.72, eigenvalue = 3.17 and explained variance = 11.73%) and intentions of political behavior (2 items, factorial loads between 0, 70 and 0.72, alpha = 0.80, eigenvalue = 1.8 and explained variance = 6.8%). It is concluded that the results strengthen the original factorial structure of the scale and show its utility for the identification of social attitudes regarding political behaviors

Applying refinement to the use of mice and rats in rheumatoid arthritis research

Rheumatoid arthritis (RA) is a painful, chronic disorder and there is currently an unmet need for effective therapies that will benefit a wide range of patients. The research and development process for therapies and treatments currently involves in vivo studies, which have the potential to cause discomfort, pain or distress. This Working Group report focuses on identifying causes of suffering within commonly used mouse and rat ‘models’ of RA, describing practical refinements to help reduce suffering and improve welfare without compromising the scientific objectives. The report also discusses other, relevant topics including identifying and minimising sources of variation within in vivo RA studies, the potential to provide pain relief including analgesia, welfare assessment, humane endpoints, reporting standards and the potential to replace animals in RA research