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Hypothetical Model (hypothetical + model)
Selected AbstractsWhat matters most to prejudice: Big Five personality, Social Dominance Orientation, or Right-Wing Authoritarianism?EUROPEAN JOURNAL OF PERSONALITY, Issue 6 2004Bo Ekehammar Whereas previous research has studied the relation of either (i) personality with prejudice, (ii) personality with social dominance orientation (SDO) and right-wing authoritarianism (RWA), or (iii) SDO and RWA with prejudice, the present research integrates all approaches within the same model. In our study (N,=,183), various causal models of the relationships among the Big Five, SDO, RWA, and Generalized Prejudice are proposed and tested. Generalized Prejudice scores were obtained from a factor analysis of the scores on various prejudice instruments (racism, sexism, prejudice toward homosexuals, and mentally disabled people), which yielded a one-factor solution. The best-fitting causal model, which was our suggested hypothetical model, showed that Big Five personality had no direct effect on Generalized Prejudice but an indirect effect transmitted through RWA and SDO, where RWA seems to capture personality aspects to a greater extent than SDO. Specifically, Generalized Prejudice was affected indirectly by Extraversion, Openness to Experience, and Conscientiousness through RWA, and by Agreeableness through SDO, whereas Neuroticism had no effect at all. The results are discussed against the background of previous research and the personality and social psychology approaches to the study of prejudice. Copyright © 2004 John Wiley & Sons, Ltd. [source] Ultrastructure of the tentacle nerve plexus and putative neural pathways in sea anemonesINVERTEBRATE BIOLOGY, Issue 3 2002Jane A. Westfall Abstract. Neurons of sea anemone tentacles receive stimuli via sensory cells and process and transmit information via a plexus of nerve fibers. The nerve plexus is best revealed by scanning electron microscopy of epidermal peels of the tentacles. The nerve plexus lies above the epidermal muscular layer where it appears as numerous parallel longitudinal and short interconnected nerve fibers in Calliactis parasitica. Bipolar and multipolar neurons are present and neurites form interneuronal and neuromuscular synaptic contacts. Transmission electron microscopy of cross sections of tentacles of small animals, both C. parasitica and Aiptasia pallida, reveals bundles of 50,100 nerve fibers lying above groups of longitudinal muscle fibers separated by intrusions of mesoglea. Smaller groups of 10,50 slender nerve fibers are oriented at right angles to the circular muscle formed by the bases of the digestive cells. The unmyelinated nerve fibers lack any glial wrapping, although some bundles of epidermal fibers are partially enveloped by cytoplasmic extensions of the muscle cells; small gastrodermal nerve bundles lie between digestive epithelial cells above their basal myonemes. A hypothetical model for sensory input and motor output in the epidermal and gastrodermal nerve plexuses of sea anemones is proposed. [source] Anthropogenic disturbance and the formation of oak savanna in central Kentucky, USAJOURNAL OF BIOGEOGRAPHY, Issue 5 2008Ryan W. McEwan Abstract Aim, To deepen understanding of the factors that influenced the formation of oak savanna in central Kentucky, USA. Particular attention was focused on the link between historical disturbance and the formation of savanna ecosystem structure. Location, Central Kentucky, USA. Methods, We used dendrochronological analysis of tree-ring samples to understand the historical growth environment of remnant savanna stems. We used release detection and branch-establishment dates to evaluate changes in tree growth and the establishment of savanna physiognomy. We contrasted our growth chronology with reference chronologies for regional tree growth, climate and human population dynamics. Results, Trees growing in Kentucky Inner Bluegrass Region (IBR) savanna remnants exhibited a period of suppression, extending from the establishment date of the tree to release events that occurred c. 1800. This release resulted in a tripling of the annual radial growth rate from levels typical of oaks suppressed under a forest canopy (< 1 mm year,1) to levels typical of open-grown stems (3 mm year,1). The growth releases in savanna trees coincided with low branch establishment. Over the release period, climatic conditions remained relatively constant and growth in regional forest trees was even; however, the growth increase in savanna stems was strongly correlated with a marked increase in Euro-American population density in the region. Main conclusions, Our data suggest that trees growing in savanna remnants originated in the understorey of a closed canopy forest. We hypothesize that Euro-American land clearing to create pasturelands released these trees from light competition and resulted in the savanna physiognomy that is apparent in remnant stands in the IBR. Although our data suggest that savanna trees originated in a forest understorey, this system structure itself may have been a result of an unprecedented lack of Native American activity in the region due to population loss associated with pandemics brought to North America by Euro-Americans. We present a hypothetical model that links human population dynamics, land-use activities and ecosystem structure. Our model focuses on the following three land-use eras: Native American habitation/utilization; land abandonment; and Euro-American land clearance. Ecological understanding of historical dynamics in other ecosystems of eastern North America may be enhanced through recognition of these eras. [source] Fat tissue, aging, and cellular senescenceAGING CELL, Issue 5 2010Tamara Tchkonia Summary Fat tissue, frequently the largest organ in humans, is at the nexus of mechanisms involved in longevity and age-related metabolic dysfunction. Fat distribution and function change dramatically throughout life. Obesity is associated with accelerated onset of diseases common in old age, while fat ablation and certain mutations affecting fat increase life span. Fat cells turn over throughout the life span. Fat cell progenitors, preadipocytes, are abundant, closely related to macrophages, and dysdifferentiate in old age, switching into a pro-inflammatory, tissue-remodeling, senescent-like state. Other mesenchymal progenitors also can acquire a pro-inflammatory, adipocyte-like phenotype with aging. We propose a hypothetical model in which cellular stress and preadipocyte overutilization with aging induce cellular senescence, leading to impaired adipogenesis, failure to sequester lipotoxic fatty acids, inflammatory cytokine and chemokine generation, and innate and adaptive immune response activation. These pro-inflammatory processes may amplify each other and have systemic consequences. This model is consistent with recent concepts about cellular senescence as a stress-responsive, adaptive phenotype that develops through multiple stages, including major metabolic and secretory readjustments, which can spread from cell to cell and can occur at any point during life. Senescence could be an alternative cell fate that develops in response to injury or metabolic dysfunction and might occur in nondividing as well as dividing cells. Consistent with this, a senescent-like state can develop in preadipocytes and fat cells from young obese individuals. Senescent, pro-inflammatory cells in fat could have profound clinical consequences because of the large size of the fat organ and its central metabolic role. [source] Ca2+ -dependent Regulation of Phototransduction,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2008Ricardo Stephen Photon absorption by rhodopsin triggers the phototransduction signaling pathway that culminates in degradation of cGMP, closure of cGMP-gated ion channels and hyperpolarization of the photoreceptor membrane. This process is accompanied by a decrease in free Ca2+ concentration in the photoreceptor cytosol sensed by Ca2+ -binding proteins that modulate phototransduction and activate the recovery phase to reestablish the photoreceptor dark potential. Guanylate cyclase-activating proteins (GCAPs) belong to the neuronal calcium sensor (NCS) family and are responsible for activating retinal guanylate cyclases (retGCs) at low Ca2+ concentrations triggering synthesis of cGMP and recovery of the dark potential. Here we review recent structural insight into the role of the N-terminal myristoylation in GCAPs and compare it to other NCS family members. We discuss previous studies identifying regions of GCAPs important for retGC1 regulation in the context of the new structural data available for myristoylated GCAP1. In addition, we present a hypothetical model for the Ca2+ -triggered conformational change in GCAPs and retGC1 regulation. Finally, we briefly discuss the involvement of mutant GCAP1 proteins in the etiology of retinal degeneration as well as the importance of other Ca2+ sensors in the modulation of phototransduction. [source] Health care professionals' grief: a model based on occupational style and copingPSYCHO-ONCOLOGY, Issue 3 2001Ellen M. Redinbaugh Many publications address grief in terminally ill patients and their loved ones. In contrast, this paper proposes a hypothetical model for grief reactions in health care professionals (HCPs) working with terminally ill patients. The model integrates three literatures: burnout, coping and personality/occupational interests. Grief-related job stress can culminate in burnout that affects over 50% of physicians treating the terminally and critically ill. Coping behaviors that attenuate burnout differ among HCPs, suggesting that nurses prefer different coping strategies when compared with physicians. The personality and occupational interests literatures provide a rationale for coping differences in HCPs. Personality characteristics associated with occupational preferences provide insight into HCPs' natural propensities for coping with stress. The model addresses personality/occupational differences among health care disciplines, thus providing a plausible explanation for coping differences among HCPs, as well as potential interventions that facilitate HCPs' adjustment to the deaths of their patients. Copyright © 2001 John Wiley & Sons, Ltd. [source] Population genetic studies of Alouatta belzebul from the Amazonian and Atlantic ForestsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2008F.F. Nascimento Abstract Cytochrome b DNA sequence data (ca. 1,140,bp) of 66 Alouatta belzebul from the Amazonian and the Atlantic Forests of Brazil were used for phylogenetic reconstructions and population studies. Our sample consisted of 60 specimens from the Amazonian Forest (captured in 1984 and 1998 in Pará-PA state) and six specimens from the Atlantic Forest (Paraíba-PB state). We found 32 haplotypes, 23 in PA-1984 (with 12 present in more than one individual), 11 in PA-1998 (with two present in more than one individual), and a single haplotype in the PB sample. Animals from PA-1984 and PA-1998 shared three haplotypes while animals from Pará and Paraíba did not share any haplotype. We found 57 variable sites, consisting of 53 transitions and four transversions, with most replacements occurring at third codon position (77.19%) and less frequently at first and second positions (10.53 and 12.28%, respectively). Genetic distance between all haplotypes varied between 0 and 1.2%. Nucleotide diversity estimates between PA-1984 haplotypes and PA-1998 haplotypes were the same (,=0.01), and haplotype diversity estimates were very similar (h=0.96 and 0.93 for PA-1984 and PA-1998, respectively). Maximum parsimony, median-joining, split decomposition, and TCS showed that PA and PB haplotypes had not drastically diverged and that subsequent radiation within these regions was not apparent. No temporal structure was found between PA-1984 and PA-1998. The sum of square deviation estimate for PA-1984 equaled 0.01 (P=0.23), in agreement with a hypothetical model of sudden expansion contrary to PA-1998 whose sum of square deviation estimate (0.40; P=0.04) was not compatible with this model, although the small sample size of PA-1998 as well as the smaller area of capture could have also accounted for this result. Fu's Fs and R2 statistical neutrality tests corroborated these propositions. Lack of drastic differentiation was attributable to the once existing connection between the Atlantic and the Amazonian forests at a non-distant past. Am. J. Primatol. 70:423,431, 2008. © 2007 Wiley-Liss, Inc. [source] Structure of the Taz2 domain of p300: insights into ligand bindingACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2009Maria Miller CBP and its paralog p300 are histone acetyl transferases that regulate gene expression by interacting with multiple transcription factors via specialized domains. The structure of a segment of human p300 protein (residues 1723,1836) corresponding to the extended zinc-binding Taz2 domain has been investigated. The crystal structure was solved by the SAD approach utilizing the anomalous diffraction signal of the bound Zn ions. The structure comprises an atypical helical bundle stabilized by three Zn ions and closely resembles the solution structures determined previously for shorter peptides. Residues 1813,1834 from the current construct form a helical extension of the C-terminal helix and make extensive crystal-contact interactions with the peptide-binding site of Taz2, providing additional insights into the mechanism of the recognition of diverse transactivation domains (TADs) by Taz2. On the basis of these results and molecular modeling, a hypothetical model of the binding of phosphorylated p53 TAD1 to Taz2 has been proposed. [source] Structure of NS1A effector domain from the influenza A/Udorn/72 virusACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2009Shuangluo Xia The nonstructural protein NS1A from influenza virus is a multifunctional virulence factor and a potent inhibitor of host immunity. It has two functional domains: an N-terminal 73-amino-acid RNA-binding domain and a C-terminal effector domain. Here, the crystallographic structure of the NS1A effector domain of influenza A/Udorn/72 virus is presented. Structure comparison with the NS1 effector domain from mouse-adapted influenza A/Puerto Rico/8/34 (PR8) virus strain reveals a similar monomer conformation but a different dimer interface. Further analysis and evaluation shows that the dimer interface observed in the structure of the PR8 NS1 effector domain is likely to be a crystallographic packing effect. A hypothetical model of the intact NS1 dimer is presented. [source] | ||||||||||