Additional Insights (additional + insight)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


NG2 proteoglycan is expressed exclusively by mural cells during vascular morphogenesis

DEVELOPMENTAL DYNAMICS, Issue 2 2001
Ugur Ozerdem
Abstract Immunofluorescence mapping demonstrates that the NG2 proteoglycan is invariably expressed by the mural cell component of mouse neovascular structures. This pattern is independent of the developmental mechanism responsible for formation of the vasculature (vasculogenesis or angiogenesis). Thus, NG2 is expressed in the embryonic heart by cardiomyocytes, in developing macrovasculature by smooth muscle cells, and in nascent microvessels by vascular pericytes. Due to the scarcity of proven markers for developing pericytes, NG2 is especially useful for identification of this cell type. The utility of NG2 as a pericyte marker is illustrated by two observations. First, pericytes are associated with endothelial tubes at an early point in microvessel development. This early interaction between pericytes and endothelial cells has important implications for the role of pericytes in the development and stabilization of microvascular tubes. Second, the pericyte to endothelial cell ratio in developing capillaries varies from tissue to tissue. Because the extent of pericyte investment is likely to affect the physical properties of the vessel in question, it is important to understand the mechanisms that control this process. Additional insight into these and other aspects of vascular morphogenesis should be possible through use of NG2 as a mural cell marker. © 2001 Wiley-Liss, Inc. [source]


Entrepreneurial Founder Teams: Factors Associated with Member Entry and Exit

ENTREPRENEURSHIP THEORY AND PRACTICE, Issue 2 2003
Deniz Ucbasaran
This exploratory study provides a review of the neglected area of entrepreneurial founder team turnover. A novel distinction is made between entrepreneurial founder team member entry and team member exit. Ninety owner-managed ventures were monitored between 1990 and 2000. Presented hypotheses relating to a team's human capital were explored using multivariate logistic regression analysis. Variables associated with entry were found not to be the same as those associated with exit. The size of the founding team was significantly negatively associated with subsequent team member entry. The link between team turnover and entrepreneurial team heterogeneity was mixed. Functional heterogeneity was weakly significantly positively associated with team member entry. Heterogeneity of prior entrepreneurial experience was significantly positively associated with team member exit. In addition, family firms were significantly negatively associated with team member exit. The average age of the team was not significantly associated with team member entry or exit. Additional insights in future research may be gathered if a broader definition of team turnover (i.e., considering team member entry and exit) is considered. Practitioner awareness of the different factors associated with team member entry and exit may encourage them to provide assistance, which facilitates the team building process over time in developing firms. Promising areas for additional research are highlighted. [source]


IRSS Psychology Theory: Telling Experiences Among Underrepresented IS Doctorates

DECISION SCIENCES JOURNAL OF INNOVATIVE EDUCATION, Issue 2 2006
Fay Cobb Payton
ABSTRACT With the changing demographics of the American workforce, the National Science Foundation, along with the U.S. Department of Commerce, has highlighted the shortage of minorities in information technology (IT) careers (http://www.ta.doc.gov/Reports/itsw/itsw.pdf). Using data from a 6-year period and the psychology Involvement-Regimen-Self Management-Social (IRSS) network theory as defined by Boice (1992), we discuss lessons learned from mentoring a group of Information Systems doctoral students who are members of a pipeline that can potentially increase the number of underrepresented faculty in business schools and who made conscious decisions to renounce the IT corporate domain. While our lessons speak to the need for more diversity awareness, we conclude that effective mentoring for underrepresented groups can and should include faculty of color (though limited in numbers) as well as majority faculty who are receptive to the needs and cultural differences of these student groups. Lastly, we draw on the work of Ethnic America to provide additional insight into our findings that are not offered by IRSS network theory. [source]


,-Amyloid immunization approaches for Alzheimer's disease

DRUG DEVELOPMENT RESEARCH, Issue 2 2002
Bruno P. Imbimbo
Abstract Alzheimer's disease (AD) represents the third leading cause of death in the U.S. and the leading cause of dementia in the elderly population. Until recently, there was little hope of efficiently combating this devastating disease. The deposition of ,-amyloid (A,) is the major pathological hallmark of AD brains. Genetic, biochemical, and pharmacological evidence support the hypothesis that A, plays a key role in the development of the disease. Thus, in the last 5 years a number of pharmacological strategies have been developed to interfere with the A, cascade. The most revolutionary of these approaches was proposed in 1999 by scientists at Elan Pharmaceuticals, which immunized against A, transgenic mice with spontaneously developing A, pathology. The immunization was achieved by subcutaneous injections of a preaggregated form of the synthetic human 42-amino acid A, emulsified with Freund's adjuvant, an immune stimulant. The vaccination caused a near complete inhibition of A, plaque formation in younger animals and a marked reduction of the A, burden in older animals. The effects on A, plaques were accompanied by a reduction of A,-associated astrogliosis and neuritic dystrophy. These results were later confirmed by other groups with similar vaccination protocols, which also demonstrated that the A, immunization of transgenic animals normalize or reduce the cognitive impairment associated with A, pathology. Interestingly, effective removal of brain A, plaques was also obtained by peripherally administering A, antibodies. The mechanism with which the vaccine increases A, clearance is not fully understood. Centrally, the vaccine appears to activate A, phagocytosis by microglial monocytes. Peripherally, serum A, antibodies bind and sequester A,, thus altering its equilibrium between CNS and plasma. The dramatic results obtained in animal models of AD raised unprecedented hopes for both a preventive and a curative intervention for this devastating disorder. A vaccine preparation for human use (AN-1792) composed of preaggregated human A,42 peptide and a highly purified saponin derivative (QS-21) was developed by Elan Pharmaceuticals and Wyeth Ayerst and tested in AD patients. Unfortunately, a Phase IIa study aimed at evaluating the safety and immunological activity of AN-1792 in 360 AD patients was discontinued because 15 subjects receiving the vaccine developed serious signs of CNS inflammation. Both central activation of cytotoxic T cells and autoimmune reactions were proposed as potential mechanisms of toxicity. Other therapeutic A, vaccination strategies are being pursued, including immuno-conjugates and monoclonal antibodies. The future of these and other A, immunization approaches depend on a clear understanding of the mechanism of A, clearance and additional insight into the role of inflammation in the AD brain. Drug Dev. Res. 56:150,162, 2002. © 2002 Wiley-Liss, Inc. [source]


Screening the Hanford tanks for trapped gas

ENVIRONMETRICS, Issue 5-6 2002
Paul Whitney
Abstract The Hanford Site is home to 177 large, underground nuclear waste storage tanks. This article describes a screening study carried out in the mid 1990s that used the tank waste level measurements to assess the tanks for potential flammable gas hazards. At the time of the study, 25 of the 177 tanks were on the flammable gas watch list. The use of this monitoring data provided additional insight, resulting in operational changes on the Hanford site. The waste level measurements used in this study were made primarily to monitor the tanks for leaks and intrusions. Four measurement devices are widely used in these tanks. Three of these measure the level of the waste surface. The remaining device measures from within a well embedded in the waste, thereby monitoring the liquid level even if the liquid level is below a dry waste crust. The data from each of the four measurement devices were utilized in this investigation. The analytic method used for this screening was to look for an inverse correlation between waste level measurements and ambient atmospheric pressure. If the waste level in a tank decreases with an increase in ambient atmospheric pressure, then the compressibility may be attributed to gas trapped within the waste. In this article, this methodology is not used to estimate the volume of gas trapped in the waste. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Development of human plasmacytoid dendritic cells depends on the combined action of the basic helix-loop-helix factor E2-2 and the Ets factor Spi-B,

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2008
Maho Nagasawa
Abstract Plasmacytoid dendritic cells (pDC) are central players in the innate and adaptive immune response against viral infections. The molecular mechanism that underlies pDC development from progenitor cells is only beginning to be elucidated. Previously, we reported that the Ets factor Spi-B and the inhibitors of DNA binding protein 2 (Id2) or Id3, which antagonize E-protein activity, are crucially involved in promoting or impairing pDC development, respectively. Here we show that the basic helix-loop-helix protein E2-2 is predominantly expressed in pDC, but not in their progenitor cells or conventional DC. Forced expression of E2-2 in progenitor cells stimulated pDC development. Conversely, inhibition of E2-2 expression by RNA interference impaired the generation of pDC suggesting a key role of E2-2 in development of these cells. Notably, Spi-B was unable to overcome the Id2 enforced block in pDC development and moreover Spi-B transduced pDC expressed reduced Id2 levels. This might indicate that Spi-B contributes to pDC development by promoting E2-2 activity. Consistent with notion, simultaneous overexpression of E2-2 and Spi-B in progenitor cells further stimulated pDC development. Together our results provide additional insight into the transcriptional network controlling pDC development as evidenced by the joint venture of E2-2 and Spi-B. [source]


CD4+CD25, effector T-cells inhibit hippocampal long-term potentiation in vitro

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2007
Gil M. Lewitus
Abstract During neuroinflammation T-cells invade the CNS, and may lead to the development and progression of several pathologies, of which multiple sclerosis is the most common. In these pathologies neuroinflammation is often associated with cognitive dysfunction. Using mouse hippocampal slices, we show here that CD4+CD25, T-cells inhibit long-term potentiation (LTP) induced by high-frequency stimulation. The T-cell-mediated inhibition of LTP can be prevented by blockade of ,-aminobutyric acid (GABA)A receptors. These findings provide additional insight into the multiple functions of T-cells in CNS pathologies. [source]


Nuclear factor-,B contributes to interleukin-4- and interferon-dependent polymeric immunoglobulin receptor expression in human intestinal epithelial cells

IMMUNOLOGY, Issue 1 2004
Laynez W. Ackermann
Summary Polymeric immunoglobulins (pIgs) that are present at mucosal surfaces play key roles in both the innate and adaptive immune responses. These pIgs are delivered to the mucosal surface via transcytosis across the epithelium, a process mediated by the polymeric immunoglobulin receptor (pIgR). Previous studies demonstrate that expression of the pIgR is regulated by multiple immunomodulatory factors including interleukin-4 (IL-4) and interferon-, (IFN-,). In studies using human intestinal epithelial cells (HT29), multiple inhibitors of the transcription factor nuclear factor-,B (NF-,B), including a dominant negative I,B,-serine mutant, inhibited both IL-4- and IFN-dependent increases in pIgR expression. Under identical conditions, NF-,B inhibitors had no effect on cytokine-dependent increases in expression of the transcription factor interferon regulatory factor-1. Over-expression of the I,B,-serine mutant also inhibited reporter gene expression in response to IL-4, TNF-,, IL-1,, and in some cases IFN-, using constructs with sequences from the pIgR promoter. Reduced levels of pIgR were observed even when inhibitors were added ,24 hr after cytokines suggesting that prolonged activation of NF-,B is required. Finally, reporter gene studies with NF-,B enhancer elements indicated that IFN-, alone and IL-4 in combination with other cytokines activated NF-,B in HT29 cells. Together, these studies provide additional insight into the signalling pathways that contribute to expression of the pIgR, a critical player in mucosal immunity. [source]


Wrapped input selection using multilayer perceptrons for repeat-purchase modeling in direct marketing

INTELLIGENT SYSTEMS IN ACCOUNTING, FINANCE & MANAGEMENT, Issue 2 2001
Stijn Viaene
In this paper, we try to validate existing theory on and develop additional insight into repeat-purchase behavior in a direct marketing setting by means of an illuminating case study. The case involves the detection and qualification of the most relevant RFM (Recency, Frequency and Monetary) variables, using a neural network wrapper as our input pruning method. Results indicate that elimination of redundant and/or irrelevant inputs by means of the discussed input selection method allows us to significantly reduce model complexity without degrading the predictive generalization ability. It is precisely this issue that will enable us to infer some interesting marketing conclusions concerning the relative importance of the RFM predictor categories and their operationalizations. The empirical findings highlight the importance of a combined use of RFM variables in predicting repeat-purchase behavior. However, the study also reveals the dominant role of the frequency category. Results indicate that a model including only frequency variables still yields satisfactory classification accuracy compared to the optimally reduced model. Copyright © 2001 John Wiley & Sons, Ltd. [source]


Semilocalized approach to investigation of chemical reactivity

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2003
V. GineityteArticle first published online: 21 JUL 200
Abstract Application of the power series for the one-electron density matrix Gineityte, V., J Mol Struct Theochem 1995, 343, 183 to the case of two interacting molecules is shown to yield a semilocalized approach to investigate chemical reactivity, which is characterized by the following distinctive features: (1) Electron density (ED) redistributions embracing orbitals of the reaction centers of both molecules and of their neighboring fragments are studied instead of the total intermolecular interaction energy; (2) the ED redistributions are expressed directly in the basis of fragmental orbitals (FOs) without passing to the basis of delocalized molecular orbitals (MOs) of initial molecules; (3) terms describing the ED redistributions due to an intermolecular contact arise as additive corrections to the purely monomolecular terms and thereby may be analyzed independently; (4) local ED redistributions only between orbitals of the reaction centers of both molecules are described by lower-order ter s of the power series, whereas those embracing both the reaction centers and their neighborhoods are represented by higher-order terms. As opposed to the standard perturbative methods based on invoking the delocalized (canonical) MOs of isolated molecules, the results of the approach suggested are in-line with the well-known intuition-based concepts of the classic chemistry concerning reactivity, namely, with the assumption about different roles of the reaction center and of its neighborhood in a chemical process, with the expectation about extinction of the indirect influence of a certain fragment (substituent) when its distance from the reaction center grows, etc. Such a parallelism yields quantum chemical analogs for the classic concepts and thereby gives an additional insight into their nature. The scope of validity of these concepts also is discussed. Applicability of the approach suggested to specific chemical problems is illustrated by a brief consideration of the SN2 and AdE2 reactions. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 302,316, 2003 [source]


Imaging biomarkers in multiple sclerosis

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2010
M. Filippi MD
Abstract Recent years have witnessed impressive advances in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI provides crucial pieces of information for the diagnosis of MS. However, the correlation between the burden of lesions observed on conventional MRI scans and the clinical manifestations of the disease remains weak. The discrepancy between clinical and conventional MRI findings in MS is explained, at least partially, by the limited ability of conventional MRI to characterize and quantify the heterogeneous features of MS pathology. Other quantitative MR-based techniques, however, have the potential to overcome such a limitation of conventional MRI. Indeed, magnetization transfer MRI, diffusion tensor MRI, proton MR spectroscopy, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. Such techniques are likely to benefit from the use of high-field MR systems and thus allow in the near future providing additional insight into all these aspects of the disease. This review summarizes how MRI is dramatically changing our understanding of the factors associated with the accumulation of irreversible disability in MS and highlights the reasons why they should be used more extensively in studies of disease evolution and clinical trials. J. Magn. Reson. Imaging 2010;31:770,788. ©2010 Wiley-Liss, Inc. [source]


The influence of tuber mineral element composition as a function of geographical location on acrylamide formation in different Italian potato genotypes

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2010
Anne Whittaker
Abstract BACKGROUND: The present study was aimed at examining the effect of tuber mineral composition, distinctive for geographical location, on the expression of acrylamide precursors in three potato genotypes (Arinda, Rossa di Cetica and Sieglinde) in three Italian potato cultivation regions (Puglia, Sicily and Tuscany). RESULTS: Sucrose and amino acids were not correlated with acrylamide formation. In contrast, reducing sugars, limiting with respect to the principal amino acid precursor asparagine, were positively correlated with acrylamide. From analysis of variance, both acrylamide and reducing sugars were not significant for variety but highly significant for location, with higher levels occurring in all three varieties cultivated in Tuscany, followed by Sicily and Puglia respectively. Reducing sugars were negatively correlated with K and Ca and positively correlated with Zn and Cu. Neither N nor P was correlated with reducing sugar content. Path analysis, a statistical technique distinguishing causation and correlation between variables, was implemented to provide additional insight on the interactions between mineral elements and reducing sugars under open field conditions. The variation in reducing sugars in all three varieties was shown to be attributable to Zn. CONCLUSION: Cultivation location has a significant impact on the composition of tuber mineral elements and, as a result, on genotype in the expression of reducing sugars. The negative correlation between Zn and K and the variation in reducing sugar content attributed to the element Zn, which is particularly available in acid soils, are important factors warranting future research aimed at reducing acrylamide formation from an agronomic perspective. Copyright © 2010 Society of Chemical Industry [source]


Refining the Explanation of Cotard's Delusion

MIND & LANGUAGE, Issue 1 2000
Philip Gerrans
Recent work in cognitive neuropsychiatry explains the Capgras and Cotard delusions as alternative explanations of unusual qualitative states caused by dam-age to an affective component of the face recognition system. The difference between the delusions results from differences in attributional style. Cotard patients typically exhibit a style of internal attribution associated with depression, while Capgras patients exhibit the external attribution style more typical of paranoia. Thus the Cotard patient attributes her condition to drastic changes in herself and the Capgras patient attributes the same changes to alterations in the environment. I suggest three modifications to this explanation. Firstly, the nature of the affective deficit in Cotard cases may be more global than in Capgras cases, resulting from the diffuse effects of the neurochemical substrate of depression. Secondly, this explanation gives us additional insight into the content of the delusion. It is unsurprising that persons whose global affective responses were suppressed would explain their lack of response by saying that they had no bodily existence. Finally I suggest that in Cotard cases the delusion is produced by a reasoning deficit, rather than attributional style. [source]


Hutchinson-Gilford progeria syndrome: oral and craniofacial phenotypes

ORAL DISEASES, Issue 3 2009
DL Domingo
Objective:, Hutchinson-Gilford progeria syndrome (HGPS) is a rare early-onset accelerated senescence syndrome. In HGPS, a recently identified de novo dominant mutation of the lamin A gene (LMNA) produces abnormal lamin A, resulting in compromised nuclear membrane integrity. Clinical features include sclerotic skin, cardiovascular and bone abnormalities, and marked growth retardation. Craniofacial features include ,bird-like' facies, alopecia, craniofacial disproportion, and dental crowding. Our prospective study describes dental, oral soft tissue, and craniofacial bone features in HGPS. Methods:, Fifteen patients with confirmed p.G608G LMNA mutation (1,17 years, seven males, eight females) received comprehensive oral evaluations. Anomalies of oral soft tissue, gnathic bones, and dentition were identified. Results:, Radiographic findings included hypodontia (n = 7), dysmorphic teeth (n = 5), steep mandibular angles (n = 11), and thin basal bone (n = 11). Soft tissue findings included ogival palatal arch (n = 8), median sagittal palatal fissure (n = 7), and ankyloglossia (n = 7). Calculated dental ages (9 months to 11 years 2 months) were significantly lower than chronological ages (1 year 6 months to 17 years 8 months) (P = 0.002). Eleven children manifested a shorter mandibular body, anterior/posterior cranial base and ramus, but a larger gonial angle, compared to age/gender/race norms. Conclusion:, Novel oral-craniofacial phenotypes and quantification of previously reported features are presented. Our findings expand the HGPS phenotype and provide additional insight into the complex pathogenesis of HGPS. [source]


Phonons in porous media at intermediate frequencies

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004
J. H. Page
Abstract Using ultrasonic techniques, the phonon diffusion coefficient and density of states have been measured at intermediate frequencies in a porous solid network of sintered glass beads. A transition to a very strong scattering regime is observed, whereupon the diffusion coefficient becomes independent of frequency. Near crossover, the density of states is enhanced and exhibits a broad maximum. These data are in good overall agreement with a lattice-based percolation model, and give additional insight into the effects of strong scattering on phonon transport in disorderd media. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Hydrophile scanning as a complement to alanine scanning for exploring and manipulating protein,protein recognition: Application to the Bim BH3 domain

PROTEIN SCIENCE, Issue 7 2008
Melissa D. Boersma
Abstract Alanine scanning has been widely employed as a method of identifying side chains that play important roles in protein,protein and protein,peptide interactions. Here we show how an analogous and complementary technique, hydrophile scanning, can provide additional insight on such interactions. Mutation of a wild-type residue to alanine removes most of the side-chain atoms, and the effect of this removal is typically interpreted to indicate contribution of the deleted side chain to the stability of the complex. Hydrophile scanning involves systematic mutation of wild-type residues to a cationic or anionic residue (lysine or glutamic acid, in this case). We find that the results of these mutations provide insights on interactions between polypeptide surfaces that are complementary to the information obtained via alanine scanning. We have applied this technique to a peptide that corresponds to the BH3 domain of the pro-apoptotic protein Bim. The wild-type Bim BH3 domain binds strongly to the anti-apoptotic proteins Bcl-xL and Mcl-1. Combining information from the alanine, lysine, and glutamic acid scans has enabled us to identify Bim BH3 domain mutants containing only two or three sequence changes that bind very selectively either to Bcl-xL or Mcl-1. Our findings suggest that hydrophile scanning may prove to be a broadly useful tool for revealing sources of protein,protein recognition and for engineering selectivity into natural sequences [source]


Genomic-scale comparison of sequence- and structure-based methods of function prediction: Does structure provide additional insight?

PROTEIN SCIENCE, Issue 5 2001
Jacquelyn S. Fetrow
Abstract A function annotation method using the sequence-to-structure-to-function paradigm is applied to the identification of all disulfide oxidoreductases in the Saccharomyces cerevisiae genome. The method identifies 27 sequences as potential disulfide oxidoreductases. All previously known thioredoxins, glutaredoxins, and disulfide isomerases are correctly identified. Three of the 27 predictions are probable false-positives. Three novel predictions, which subsequently have been experimentally validated, are presented. Two additional novel predictions suggest a disulfide oxidoreductase regulatory mechanism for two subunits (OST3 and OST6) of the yeast oligosaccharyltransferase complex. Based on homology, this prediction can be extended to a potential tumor suppressor gene, N33, in humans, whose biochemical function was not previously known. Attempts to obtain a folded, active N33 construct to test the prediction were unsuccessful. The results show that structure prediction coupled with biochemically relevant structural motifs is a powerful method for the function annotation of genome sequences and can provide more detailed, robust predictions than function prediction methods that rely on sequence comparison alone. [source]


Stable isotope variation in wool as a means to establish Turkish carpet provenance,

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2005
Robert E. M. Hedges
The problem of establishing the provenance of carpets of artistic and historical importance is well known. We have addressed this by investigating whether there is sufficient geographical variation in the stable isotopes in wool (namely C, N and S) between key areas of Turkey to be able to recognize the different regions where carpets were made. Here we report results from modern wool samples taken from the winter growth of sheep in 2003/2004 from 13 carpet-producing sites. Although each site has a characteristic composition, most sites cannot be distinguished from each other, and the overall isotopic pattern is unexpectedly complicated. Thus in Western Turkey there is no sign of sea-spray effects in the ,34S values for sites close (10,km) to the sea, while, in the Konya Basin (Central Turkey), the ,34S values vary significantly between nearby sites. Two ,urban' settlements where sheep are now raised have dramatically higher ,15N values. It is nevertheless possible that certain production centers may have distinct signatures, and further work will compare carpets from known sources with the currently produced wool values. The results also provide additional insight into the natural variation found in archaeological faunal isotopic values, e.g. in bone collagen. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Brief communication: Methods of sequence heterochrony for describing modular developmental changes in human evolution

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009
Gregory E. Blomquist
Abstract Interest in the developmental changes leading to apomorphic features of human anatomy is longstanding. Although most research has focused on quantitative measures of size and shape, additional information may be available in the sequence of events in development, including aspects of phenotypic integration. I apply two recently proposed techniques for analyzing developmental sequences to literature data on human and chimpanzee age of limb element ossification center appearance in radiographs. The event-pair cracking method of Jeffery et al. (Syst Biol 51 [2002] 478,491) offers little additional insight on sequence differences in this data set than a simpler difference of ranks. Both reveal shifts in timing that are likely related to locomotor differences between the two species. Poe's (Evolution 58 [2004] 1852,1855) test for modularity in a sequence identifies the ankle, wrist, and hind limb as developmental modules, which may correspond to localized combinations of developmental genes. Ossification patterns of the rays of the hand and foot show little modularity. Integrating these and other methods of sequence analysis with traditional metrics of size and shape remains an underdeveloped area of inquiry. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source]


Information, Agreement Design, and the Durability of Civil War Settlements

AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 2 2010
Michaela Mattes
Civil war is usually examined from the perspective of commitment problems. This approach provides considerable insight regarding which civil war agreement provisions reduce the chance of renewed fighting. Yet, additional insight can be gained by examining information asymmetries as a potential cause of civil war recurrence. We argue that significant uncertainty regarding military capabilities may persist after fighting ends and that this uncertainty may lead to the breakdown of peace. However, carefully designed peace agreements can guard against renewed civil war by calling for international monitoring, making the belligerents submit military information to third parties, and providing for verification of this information. Our empirical analysis of 51 civil war settlements between 1945 and 2005 shows that these provisions significantly reduce the risk of new civil war. Encouraging the adoption of these provisions may be a useful policy in the international community's effort to establish peace in civil-war-torn societies. [source]


Host and non-host pathogens elicit different jasmonate/ethylene responses in Arabidopsis

THE PLANT JOURNAL, Issue 5 2004
Laurent Zimmerli
Summary Arabidopsis does not support the growth and asexual reproduction of the barley pathogen, Blumeria graminis f. sp. hordei Bgh). A majority of germlings fail to penetrate the epidermal cell wall and papillae. To gain additional insight into this interaction, we determined whether the salicylic acid (SA) or jasmonate (JA)/ethylene (ET) defence pathways played a role in blocking barley powdery mildew infections. Only the eds1 mutant and NahG transgenics supported a modest increase in penetration success by the barley powdery mildew. We also compared the global gene expression patterns of Arabidopsis inoculated with the non-host barley powdery mildew to those inoculated with a virulent, host powdery mildew, Erysiphe cichoracearum. Genes repressed by inoculations with non-host and host powdery mildews relative to non-inoculated control plants accounted for two-thirds of the differentially expressed genes. A majority of these genes encoded components of photosynthesis and general metabolism. Consistent with this observation, Arabidopsis growth was inhibited following inoculation with Bgh, suggesting a shift in resource allocation from growth to defence. A number of defence-associated genes were induced during both interactions. These genes likely are components of basal defence responses, which do not effectively block host powdery mildew infections. In addition, genes encoding defensins, anti-microbial peptides whose expression is under the control of the JA/ET signalling pathway, were induced exclusively by non-host pathogens. Ectopic activation of JA/ET signalling protected Arabidopsis against two biotrophic host pathogens. Taken together, these data suggest that biotrophic host pathogens must either suppress or fail to elicit the JA/ET signal transduction pathway. [source]


Intervertebral disc degeneration: New insights based on "skipped" level disc pathology

ARTHRITIS & RHEUMATISM, Issue 8 2010
Kenneth M. C. Cheung
Objective Typically, age and abnormal physical loading ("wear and tear") have been associated with the development of intervertebral disc degeneration. In the past decade, various additional etiologic factors for disc degeneration have been sporadically reported in the literature; however, many investigators continue to place tremendous emphasis on the effects of age and biomechanics associated with disc degeneration. The aim of this study was to provide additional insight into the notion that age and biomechanics are key factors in the development of disc degeneration. To this end, we addressed the prevalence of and risk factors associated with a unique pattern of disc degeneration of the lumbar spine, "skipped" level (nonconsecutive) disc degeneration (SLDD). Methods As part of a large genetics-based study in southern Chinese individuals (n = 1,989), a cross-sectional analysis was performed in subjects exhibiting disc degeneration in ,2 levels (n = 838) who were then categorized as having SLDD (n = 174) or non-SLDD (contiguous, multilevel; n = 664). Various radiographic parameters were assessed based on T2-weighted magnetic resonance imaging (MRI). Subject demographics were assessed, and univariate and multivariate logistic regression analyses were performed. Results Overall, 8.7% of the whole population (n = 1,989) had SLDD, while it was present in 20.8% of subjects with multilevel disc degeneration (n = 838). SLDD was more prevalent in male subjects (adjusted odds ratio [OR] 1.48, 95% confidence interval [95% CI] 1.04,2.10, P = 0.028). SLDD was significantly associated with the presence of Schmorl's nodes (adjusted OR 2.72, 95% CI 1.78,4.15, P < 0.001), which also presented in levels with no disc degeneration. A history of disc bulge/extrusion (P = 0.004) and/or a history of back injury (P = 0.010) was significantly associated with non-SLDD, and a greater degree of overall severity of disc degeneration was also associated with non-SLDD. Other demographic and MRI findings did not significantly differ between groups. Conclusion To our knowledge, this report is the first to describe the prevalence and risk factors associated with SLDD. Our study challenges the paradigm that age and biomechanics are the key factors associated with the development of disc degeneration. Although age and biomechanical factors may play a role in the manifestation of disc degeneration, our novel findings of SLDD patterns provide further awareness of and support for the notion that additional etiologic factors may play a role in the development of disc degeneration. Such factors warrant further investigation to shed light on the cause of disc degeneration. [source]


On Models for Binomial Data with Random Numbers of Trials

BIOMETRICS, Issue 2 2007
W. Scott Comulada
Summary A binomial outcome is a count s of the number of successes out of the total number of independent trials n=s+f, where f is a count of the failures. The n are random variables not fixed by design in many studies. Joint modeling of (s, f) can provide additional insight into the science and into the probability , of success that cannot be directly incorporated by the logistic regression model. Observations where n= 0 are excluded from the binomial analysis yet may be important to understanding how , is influenced by covariates. Correlation between s and f may exist and be of direct interest. We propose Bayesian multivariate Poisson models for the bivariate response (s, f), correlated through random effects. We extend our models to the analysis of longitudinal and multivariate longitudinal binomial outcomes. Our methodology was motivated by two disparate examples, one from teratology and one from an HIV tertiary intervention study. [source]


Contrasting microcystin production and cyanobacterial population dynamics in two Planktothrix -dominated freshwater lakes

ENVIRONMENTAL MICROBIOLOGY, Issue 10 2005
Ingmar Janse
Summary Microcystin concentrations in two Dutch lakes with an important Planktothrix component were related to the dynamics of cyanobacterial genotypes and biovolumes. Genotype composition was analysed by using denaturing gradient gel electrophoresis (DGGE) profiling of the intergenic transcribed spacer region of the rrn operon (rRNA-ITS), and biovolumes were measured by using microscopy. In Lake Tjeukemeer, microcystins were present throughout summer (maximum concentration 30 µg l,1) while cyanobacterial diversity was low and very constant. The dominant phototroph was Planktothrix agardhii. In contrast, Lake Klinckenberg showed a high microcystin peak (up to 140 µg l,1) of short duration. In this lake, cyanobacterial diversity was higher and very dynamic with apparent genotype successions. Several genotypes derived from DGGE field profiles matched with genotypes from cultures isolated from field samples. The microcystin peak measured in Lake Klinckenberg could be confidently linked to a bloom of Planktothrix rubescens, as microscopic and genotypic analysis showed identity of bloom samples and a toxin-producing P. rubescens culture. Toxin-producing genotypes were detected in the microbial community before they reached densities at which they were detected by using microscopy. Cyanobacterial biovolumes provided additional insights in bloom dynamics. In both lakes, the microcystin content per cell was highest at the onset of the blooms. Our results suggest that while genotypic characterization of a lake can be valuable for detection of toxic organisms, for some lakes a monitoring of algal biomass has sufficient predictive value for an assessment of toxin production. [source]


Using BiowinÔ, Bayes, and batteries to predict ready biodegradability

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004
Robert S. Boethling
Abstract Wether or not a given chemical substance is readily biodegradable is an important piece of information in risk screening for both new and existing chemicals. Despite the relatively low cost of Organization for Economic Cooperation and Development tests, data are often unavailable and biodegradability must be estimated. In this paper, we focus on the predictive value of selected BiowinÔ models and model batteries using Bayesian analysis. Posterior probabilities, calculated based on performance with the model training sets using Bayes' theorem, were closely matched by actual performance with an expanded set of 374 premanufacture notice (PMN) substances. Further analysis suggested that a simple battery consisting of Biowin3 (survey ultimate biodegradation model) and Biowin5 (Ministry of International Trade and Industry [MITI] linear model) would have enhanced predictive power in comparison to individual models. Application of the battery to PMN substances showed that performance matched expectation. This approach significantly reduced both false positives for ready biodegradability and the overall misclassification rate. Similar results were obtained for a set of 63 pharmaceuticals using a battery consisting of Biowin3 and Biowin6 (MITI nonlinear model). Biodegradation data for PMNs tested in multiple ready tests or both inherent and ready biodegradation tests yielded additional insights that may be useful in risk screening. [source]


Performance analysis of a generic system model for uncoded IDMA using serial and parallel interference cancellation,

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2008
Oliver Nagy
This paper shows how to accurately describe a fully synchronised interleave division multiple access (IDMA) scheme without channel coding by a matrix model. This model allows the derivation of the optimal detector and provides additional insights into the IDMA principle, and we show that the matrices are structured and sparse. We use BER and EXIT charts to study the performance of parallel and serial interference cancellation schemes and demonstrate that the latter converges faster and is independent of the scrambling code. Any bit interleaved DS-CDMA system can be viewed as a special case of IDMA, and an IDMA receiver can therefore be used to detect DS-CDMA signals. Copyright © 2008 John Wiley & Sons, Ltd. [source]


GENETICS AND RECENT HUMAN EVOLUTION

EVOLUTION, Issue 7 2007
Alan R. Templeton
Starting with "mitochondrial Eve" in 1987, genetics has played an increasingly important role in studies of the last two million years of human evolution. It initially appeared that genetic data resolved the basic models of recent human evolution in favor of the "out-of-Africa replacement" hypothesis in which anatomically modern humans evolved in Africa about 150,000 years ago, started to spread throughout the world about 100,000 years ago, and subsequently drove to complete genetic extinction (replacement) all other human populations in Eurasia. Unfortunately, many of the genetic studies on recent human evolution have suffered from scientific flaws, including misrepresenting the models of recent human evolution, focusing upon hypothesis compatibility rather than hypothesis testing, committing the ecological fallacy, and failing to consider a broader array of alternative hypotheses. Once these flaws are corrected, there is actually little genetic support for the out-of-Africa replacement hypothesis. Indeed, when genetic data are used in a hypothesis-testing framework, the out-of-Africa replacement hypothesis is strongly rejected. The model of recent human evolution that emerges from a statistical hypothesis-testing framework does not correspond to any of the traditional models of human evolution, but it is compatible with fossil and archaeological data. These studies also reveal that any one gene or DNA region captures only a small part of human evolutionary history, so multilocus studies are essential. As more and more loci became available, genetics will undoubtedly offer additional insights and resolutions of human evolution. [source]


An Anisotropic Model for Spatial Processes

GEOGRAPHICAL ANALYSIS, Issue 1 2008
Minfeng Deng
One of the key assumptions in spatial econometric modeling is that the spatial process is isotropic, which means that direction is irrelevant in the specification of the spatial structure. On the one hand, this assumption largely reduces the complexity of the spatial models and facilitates estimation and interpretation; on the other hand, it appears rather restrictive and hard to justify in many empirical applications. In this article a very general anisotropic spatial model, which allows for a high level of flexibility in the spatial structure, is proposed. This new model can be estimated using maximum likelihood and its asymptotic properties are derived at length. When the model is applied to the well-known 1970 Boston housing prices data, it significantly outperforms the isotropic spatial lag model. It also provides interesting additional insights into the price determination process in the properties market. Finally, a Monte Carlo simulation study is used to confirm the optimal properties of the model. [source]


An overview of 45 published database resources for complementary and alternative medicine

HEALTH INFORMATION & LIBRARIES JOURNAL, Issue 2 2010
Katja Boehm
Background:, Complementary and alternative medicine (CAM) has succeeded to implement itself in the academic context of universities. In order to get information on CAM, clinicians, researchers and healthcare professionals as well as the lay public are increasingly turning to online portals and databases, which disseminate relevant resources. One specific type of online information retrieval systems, namely the database, is being reviewed in this article. Question:, This overview aims at systematically retrieving and describing all databases covering the field of CAM. One of the requirements for inclusion was that the database would also have to be published in a medical journal. Data sources:, The databases amed, CAMbase, embase, and medline/PubMed were searched between December 2008 and December 2009 for publications relevant to CAM databases. The authors' specialist library was also searched for grey literature to be included. Study selection:, All included databases were then visited online and information on the context, structure and volume of the database was extracted. Main results:, Forty-five databases were included in this overview. Databases covered herbal therapies (n = 11), traditional Chinese medicine (n = 9) and some dealt with a vast number of CAM modalities (n = 9), amongst others. The amount of time the databases had been in existence ranged from 4 to 53 years. Countries of origin included the USA (n = 14), UK (n = 7) and Germany (n = 6), amongst others. The main language in 42 of 45 databases was English. Conclusions:, Although this overview is quite comprehensive with respect to the field of CAM, certain CAM practices such as chiropractic, massage, reflexology, meditation or yoga may not have been covered adequately. A more detailed assessment of the quality of the included databases might give additional insights into the listed resources. The creation of a personalised meta-search engine is suggested, towards which this overview could be seen as a first step. [source]


The Ordinance for the trial of Charles I

HISTORICAL RESEARCH, Issue 193 2003
Sean Kelsey
During the English civil wars, parliament passed legislation in the form of ordinances , statute laws not requiring the king's assent. In late December 1648 a rump house of commons drafted an Ordinance for the trial of Charles I. Its rejection by the house of lords prompted the Commons to assume the power to legislate alone. The abortive Ordinance and the more famous Act for the trial of the king differ in ways which lend minor additional insights into the struggles at Westminster which complicated the task of bringing Charles I to justice. [source]