cssi/SciSciGPT-SciSciNet huggingface dataset:
The pgaABCD Locus of Escherichia coli Promotes the Synthesis of a Polysaccharide Adhesin Required for Biofilm Formation

Production of a polysaccharide matrix is a hallmark of bacterial biofilms, but the composition of matrix polysaccharides and their functions are not widely understood. Previous studies of the regulation of Escherichia coli biofilm formation suggested the involvement of an unknown adhesin. We now establish that the pgaABCD (formerly ycdSRQP) locus affects biofilm development by promoting abiotic surface binding and intercellular adhesion. All of the pga genes are required for optimal biofilm formation under a variety of growth conditions. A pga-dependent cell-bound polysaccharide was isolated and determined by nuclear magnetic resonance analyses to consist of unbranched beta-1,6-N-acetyl-D-glucosamine, a polymer previously unknown from the gram-negative bacteria but involved in adhesion by staphylococci. The pga genes are predicted to encode envelope proteins involved in synthesis, translocation, and possibly surface docking of this polysaccharide. As predicted, if poly-beta-1,6-GlcNAc (PGA) mediates cohesion, metaperiodate caused biofilm dispersal and the release of intact cells, whereas treatment with protease or other lytic enzymes had no effect. The pgaABCD operon exhibits features of a horizontally transferred locus and is present in a variety of eubacteria. Therefore, we propose that PGA serves as an adhesin that stabilizes biofilms of E. coli and other bacteria.
Calculating power for the comparison of dependent κ-coefficients

Summary. In the psychosocial and medical sciences, some studies are designed to assess the agreement between different raters and/or different instruments. Often the same sample will be used to compare the agreement between two or more assessment methods for simplicity and to take advantage of the positive correlation of the ratings. Although sample size calculations have become an important element in the design of research projects, such methods for agreement studies are scarce. We adapt the generalized estimating equations approach for modelling dependent κ-statistics to estimate the sample size that is required for dependent agreement studies. We calculate the power based on a Wald test for the equality of two dependent κ-statistics. The Wald test statistic has a non-central χ2-distribution with non-centrality parameter that can be estimated with minimal assumptions. The method proposed is useful for agreement studies with two raters and two instruments, and is easily extendable to multiple raters and multiple instruments. Furthermore, the method proposed allows for rater bias. Power calculations for binary ratings under various scenarios are presented. Analyses of two biomedical studies are used for illustration.
A modification of the method of successive intervals.

A modification of the method of successive intervals is presented which yields scale values correlating .995 with those from Thurstone's method described by Saffir. Values yielded by the present method can be obtained in 25 per cent of the time required by the older method and are shown to be, on apriori grounds, more reliable as well.
Perceived physical environment and physical activity across one year among adolescent girls: Self-efficacy as a possible mediator?

Abstract Purpose This study involved an examination of the direct and mediated effects of perceived equipment accessibility and neighborhood safety on physical activity across a one-year period among adolescent girls. Methods Adolescent girls (N = 1,038) completed self-report measures of perceived environment, barriers self-efficacy, and physical activity in the Spring semesters of 1999 (baseline) and 2000 (follow-up) when students were in the 8th and 9th grades. Results An initial analysis demonstrated that neighborhood safety did not exhibit cross-sectional or longitudinal direct effects on physical activity, whereas equipment accessibility exhibited a statistically significant cross-sectional, but not longitudinal, direct effect on physical activity. The secondary analysis demonstrated that self-efficacy for overcoming barriers mediated the cross-sectional effect of equiment accessibility on physical activity. Conclusions We conclude that the cross-sectional effect of perceived equipment accessibility on physical activity is mediated by self-efficacy for overcoming barriers among adolescent girls. This is consistent with the reciprocal relationships among the environment, person, and behavior described by social-cognitive theory.
Can ethnopharmacology contribute to the development of new anticancer drugs

Abstract Ethnopharmacologic and ethnomedical information has been poorly utilized in the past in the search for new and effective treatments for cancer. In spite of this, plants have been a very viable source of clinically useful compounds, leads for synthetic modification and tools for mechanistic studies. In this paper, a new strategy for the discovery of anticancer agents from plants is proposed in which ethnomedical information is correlated against pertinent published chemical and biological information, resulting in a priorittzation of plants for collection. Authenticated plants are extracted and the extracts tested in a broad array of more than 20 human cancer cell and mechanism-based assays through a cooperative research program involving a university, a research institute and a pharmaceutical company. Bioactivity-directed fractionation will be carried out at all three sites, with a view to identifying novel compounds which will serve as candidates for preclinical testing.
Partitioning of solutes and cosolvents between supercritical CO2 and polymer phases

Abstract In situ Fourier transform IR and UV–vis spectroscopy have been used for partitioning of solutes between supercritical (sc) CO2 and polymer phases. Partitioning of deuterated water and azo-dyes between poly(methyl methacrylate) and scCO2 have been measured. Despite the low solubilities of polar azo-dyes in scCO2 the partition coefficient of these dyes is ca. 104. In addition, the degree of partitioning of cosolvents methanol and acetone from scCO2 into cross-linked poly(dimethylsiloxane) as well as the pressure dependence of the partition coefficient have been determined. Specific intermolecular interactions have been identified and related to the cosolvent partitioning between scCO2 and polymer phases.
A threshold model of social support, adjustment, and distress after breast cancer treatment.

This study examined a threshold model which proposes that social support exhibits a curvilinear association with adjustment and distress, such that support in excess of a critical threshold level has decreasing incremental benefits. Women diagnosed with a first occurrence of breast cancer (N = 154) completed survey measures of perceived support (Social Provisions Scale), quality of life (Functional Living Index-Cancer), adjustment (Psychological Adjustment to Illness Scale) and psychological distress (Brief Symptom Inventory) approximately three weeks after surgical treatment and 8–16 months later. Consistent with a threshold model, multiple regression analyses suggested a significant curvilinear relationship between social support and distress at Time 1 and Time 2; and between social support and adjustment at Time 2. Consistent with this model, the significant bivariate correlations between social support and outcomes were accounted for almost entirely by women in the lowest quartile of support. Social support among women in the highest three quartiles was unrelated or only marginally related to adjustment and distress.
Historical Development and Present Status of the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS)

ABSTRACT Objectives To review the historical development, reliability, validity, administrative characteristics, and uses of the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS). Method The various past and current K-SADS editions were reviewed as was the literature describing their uses. Results Three DSM-IV -compatible versions of the K-SADS are in general use, 1 present state (K-SADS-P IVR) and 2 epidemiological editions (K-SADS-E and K-SADS-P/L). All 3 interviews provide a current diagnostic assessment. The K-SADS-P IVR also evaluates the worst past episode during the preceding year, while the K-SADS-E and -P/L provide a lifetime diagnosis. The K-SADS-E and -P/L are primarily categorical diagnostic interviews while the K-SADS-P IVR, which also measures symptom severity, can be used to monitor treatment response. All editions have good rater reliability. However, the quality of the validating data set for the K-SADS is limiting. Conclusions The K-SADS is a viable interview schedule to assess current, past, and lifetime diagnostic status in children and adolescents. It is has the potential to further aide in the validation of psychiatric disorders. The substantial rater training required for reliable administration and the need for more validation work remain its drawbacks.
An effective procedure for DNA isolation and voucher recovery from millimeter-scale copepods and new primers for the 18S rRNA and cytb genes

Abstract Many investigators need to determine whether individuals belong to the same species. DNA-sequence data have helped with this task, but current procedures of DNA isolation from millimeter-scale crustaceans, such as harpacticoid copepods, leave little to no voucher material for morphological analysis, and many procedures yield only enough DNA for a single amplification reaction. We therefore developed a DNA-isolation procedure that yielded essentially intact exoskeletons and sufficient DNA for multiple polymerase chain reactions. DNA-amplification success of our DNA-isolation procedure was relatively insensitive to (1) the length of preservation time from sample collection to DNA isolations and (2) the length of time the DNA was stored at − 20 °C after isolation. An additional benefit of our procedure is therefore that the DNA isolated is relatively stable. Primers available for the nuclear 18S rRNA gene and the mitochondrial cytochrome oxidase b ( cytb ) gene are known not to work for many harpacticoids. We therefore designed primers that would amplify and sequence an ~ 750-base-pair fragment of the 18S rRNA gene and others that would amplify and sequence an ~ 450-base-pair fragment of the cytb gene. Both primer sets worked for at least 12 harpacticoid families.
Audits of international relief in the Nigerian Civil War: Some political perspectives

Information from four audits, or audit-like reviews, of international relief programs in the Nigerian-Biafran war sheds considerable light on the financial sources, scope, timing of flows, and cost-efficiency associated with that complex operation. Beyond their intrinsic interest, which is heightened by two of the documents remaining unpublished, such economic data bear heavily on many political aspects of the relief effort. For example, they permit examination of the relationship, and partial disjunction, between dominance in contributions (which was mainly governmental and particularly American) and leadership in administration (which was chiefly continental European and private). They also facilitate an assessment of the massive or token proportions of these endeavors, their capacity to anticipate rather than just respond tardily to predictable catastrophes, and the extent of their entanglement in the domestic and international power fields that characterized the Nigerian conflict. For all their rather divergent modi operandi, the leading role in the relief process of the two private umbrella organizations is clearly apparent; but so too is the limited ambit of even such comparatively massive relief work within the context of an on-going civil war.
A quantitative study of the effect which a visual whole has upon its membral parts.

Ein Kreis kann in eine Ellipse mit betrachtlicher Verschiedenheit der beiden Hauptachsen verwandelt werden, ehe er aufhort, anschaulieh ein Kreis zu sein. Liegt der Kreis inmitten einer kreisformigen Anordnung von anderen figuren, so ist diese Schwelle noch weiter erhoht, im Verhaltnis 2: 3, wenn die umgebenden Figuren ebenfalls Kreise, deutlich weniger, wenn sie Ellipsen, und am wenigsten, wenn sie Quadrate sind.
A search for 89Mo

Abstract We tried to produce the 89Mo which had been previously reported as having a t 1 2 of 7·1 min. We used the 90Zr(3He, 4n)89Mo, 93Nb(p, 5n) 89Mo, and 92Mo(p, p3n)89Mo reactions. Molybdenum was chemically separated rapidly from the target, but neither new radiations nor the growth of 89Nb were observed. An upper limit on the half-life of 89Mo assuming a 9 2 + spin was set at 2 min and for the 1 2 − assumption at 1 min.
Glutathione effects on vitamin D metabolism in control and streptozotocin diabetic rat

Abstract The circulating concentration of 1,25-dihydroxycholecalciferol [1,25-(OH) 2 D 3 ] is a physiologic index of enzymatic activity of the renal 1α-hydroxylase of 25-hydroxychole-calciferol (25-OH-D 3 ). Hydroxylation of 25-OH-D 3 and circulating 1,25-(OH) 2 D 3 are decreased in the streptozotocin diabetic rat. We previously found that activity of another redox enzyme system, cytosolic superoxide dismutase, also decreased in streptozotocin diabetes, can be restored by treatment with glutathione. In the present experiment we tested the effect of glutathione treatment on vitamin D metabolism in control and diabetic rats. Enteral glutathione increased circulating 1,25-(OH) 2 D 3 and decreased 25-OH-D 3 in both control and diabetic animals. These results suggest that exogenous glutathione increases 25-OH-D 3 1α-hydroxylation both under basal conditions in the normal animal and in diabetes-induced depression.
The Road to Good Governance: Via the Path Less Accountable? The Effectiveness of Fiscal Accountability in Liberia

Accountability mechanisms are touted as a path to “good governance.” But are accountability mechanisms a sure route to achieving the objectives of “good governance”? Limited case studies have offered inconsistent evidence (Blair, 2000; Charlick, 2001; Devas & Grant, 2003). But empirical evidence of the relationships among principles of good governance—high citizen participation, low levels of corruption, high-quality service delivery—and accountability mechanisms is lacking. We examine the effectiveness of accountability mechanisms in Liberia and find relationships between measures of county level fiscal accountability and measures of good governance do not always produce expected results, making fiscal accountability mechanisms no guarantee for achieving goals of good governance.
Emplacement of a radiating dike swarm in western Vinmara Planitia, Venus: interpretation of the regional stress field orientation and subsurface magmatic configuration

Magellan radar data from western Vinmara Planitia on Venus reveal a system of radiating lineaments extending 450 km from a small central annulus. Spatial variations in lineament density, orientation, and morphology, as well as structural and volcanic correlations, provide strong evidence that formation of the lineaments was related to subsurface dike emplacement. We infer from the observed surface deformation that the dikes were emplaced laterally, at shallow depth, from a large central magma reservoir. This configuration is analogous to that of radiating dike swarms found on Earth. Because dikes inject normal to the least compressive stress direction, swarm plan view geometry will reveal the greatest horizontal compressive stress trajectories. We interpret strongly radial orientations near the swarm center to represent radial stresses linked to pressurization of the magma reservoir. Increasingly non-radial behavior dominating at greater distances is interpreted to reflect a N60E±20° regional maximum horizontal compressive stress. Contrary to previous inferences that a persistent E–W compressive stress dominated throughout, analysis of the arachnoid indicates that a N60E compressive stress must have existed across western Vinmara Planitia during a portion of its deformation. This and the absence of distributed shear within the adjacent deformation belts indicates that the regional maximum horizontal compression orientation has varied over time. Comparison between the regional stress orientations inferred from the arachnoid and several nearby ridge belts illustrates that stress orientations may potentially be useful for determining relative belt ages in areas where the timing of ridge belt formation is difficult to assess by more direct means. This demonstrates one way that identification and analysis of giant radiating dike swarms can provide new information critical for regional stress interpretations on Venus.
Lysosomal abnormalities in degenerating neurons link neuronal compromise to senile plaque development in Alzheimer disease

Antibodies to the lysosomal hydrolases, cathepsins B and D and beta-hexosaminidase A, revealed alterations of the endosomal-lysosomal system in neurons of the Alzheimer disease brain, which preceded evident degenerative changes and became marked as atrophy, neurofibrillary pathology, or chromatolysis developed. At the earliest stages of cell atrophy, hydrolase-positive lysosomes accumulated at the basal pole and then massively throughout the perikarya and proximal and proximal dendrites of affected pyramidal neurons in Alzheimer prefrontal cortex and hippocampus, far exceeding the changes of normal aging. Secondary lysosomes as well as tertiary residual bodies (lysosomes/lipofuscin) increased implying stimulated, autophagocytosis and lysosomal system activation. Less affected brain regions, such as the thalamus, displayed similar though less extensive alterations. Certain thalamic neurons exhibited a distinctive lysosome-related abnormality characterized by the presence of cell surface blebs of varying size and number filled with intense hydrolase immunoreactivity. At more advanced stages of degeneration in still intact neurons, hydrolase-positive lipofuscin, particularly in the form of abnormally large aggregates, nearly filled the cytoplasm. Similar lipofuscin aggregates were observed in abundance in the extracellular space following cell lysis and were usually associated with deposits of the beta-amyloid protein. Degenerating neurons and their processes were the major source of these aggregates within senile plaques which contained high concentrations of acid hydrolases. We have shown in previous studies that these lysosomal hydrolases in plaques are enzymatically-active. The persistence of lysosomal structures in the brain parenchyma after neurons have degenerated is a striking and potentially diagnostic feature of Alzheimer disease which has not been observed, to our knowledge, in other degenerative diseases. The lysosomal response in degenerating Alzheimer neurons represents a probable link between an early activation of the lysosomal system in at-risk, normal-appearing neurons and the end-stage contribution of lysosomes to senile plaque formation and emphasizes a slowly progressive disturbance of the lysosomal system throughout the development of Alzheimer disease.
Low Background Infrared Calibration Facility At The National Bureau Of Standards

The National Bureau of Standards (NBS) has accepted the responsibility for constructing a new facility for the calibration of radiometric sources used in low background environments. Along with the facility's development, a program has been started to study the long term needs of the calibration community and to develop appropriate new test and measurement procedures. The facility consists of a large (60 cm dia by 152 cm long) vacuum chamber whose inner volume is maintained at temperatures of less than 20 K. The radiometer is separated from the source by an isothermal wall whose temperature is actively controlled. The cryogenic cooling of the vacuum interior is accomplished by a closed cycle helium refrigerator system which also contributes to the vacuum maintenance. The source volume can accept a cubic source of up to 30 cm on a side provided the aperture is suitably located. A research and development project is underway to develop methodology to characterize optical attenuators over many orders of magnitude and over a broad wavelength range.
Absence of crystalline retinopathy after long-term therapy with β-carotene†

Abstract The retinas of twenty-six patients with protoporphyria who had received treatment with β-carotene for periods ranging from 1 to 10 years were examined for the presence of yellow crystalline deposits, similar to those recently reported in and around the maculae of individuals ingesting the related carotenoid compound canthaxanthin. No crystalline deposits were observed in any of our patients.
A Discrete Version of Green's Theorem

We formulate a discrete version of Green's theorem such that a summation of a two-dimensional function over a discrete region can be evaluated by the use of a summation over its discrete boundary. In many cases, the discrete Green theorem can result in computational gain. Applications of the discrete Green theorem to several typical image processing problems are demonstrated. We also apply it to analyze shapes of particle aggregates of Fe2O3. Experimental results of the shape study are presented.
Identification of selective enzyme inhibitors by fragment library screening.

The microbial threat to human health is growing due to the dramatic increase in the number of multidrug-resistant organisms. The decline in effective antibiotics available to treat these growing threats has provided greater urgency to the search for new antibiotics. Clearly, new approaches must be developed against novel targets to control these resistant infectious organisms. The screening of low molecular weight compounds against new protein targets provides an opportunity to identify novel inhibitors as starting points for the development of new antibiotics. Custom fragment libraries have been assembled and screened against 3 representative forms of a key enzyme in an essential microbial biosynthetic pathway. Although each of these aspartate semialdehyde dehydrogenases (ASADHs) catalyzes the same reaction and each shares identical active site functional groups, subtle differences in enzyme structures have led to different binding selectivity among the initial hits from these fragment libraries. Amino acid analogues have been identified that show selectivity for either the gram-negative or gram-positive bacterial enzyme forms. A series of benzophenone analogues selectively inhibit the gram-negative ASADH, whereas some haloacids and substituted aromatic acids have been found to inhibit only the fungal form of ASADH. Each of these low molecular weight compounds possesses high ligand binding efficiency for their target enzyme forms. These results support the goal of designing lead compounds that will selectively target ASADHs from different microbial species. (Journal of Biomolecular Screening 2010:1042-1050) Key w ords: fragment library screening, kinetic studies, aspartate semialdehyde dehydrogenase, antibiotic development, ligand binding efficiency
Indirect adaptive control for synchronous Generator: comparison of MLP/RBF neural networks approach with Lyapunov stability analysis

This paper compares two indirect adaptive neurocontrollers, namely a multilayer perceptron neurocontroller (MLPNC) and a radial basis function neurocontroller (RBFNC) to control a synchronous generator. The different damping and transient performances of two neurocontrollers are compared with those of conventional linear controllers, and analyzed based on the Lyapunov direct method.
INTENSITY DISCRIMINATION IN THE HUMAN EYE : II. THE RELATION BETWEENDeltaI/IAND INTENSITY FOR DIFFERENT PARTS OF THE SPECTRUM.

1. A new apparatus is described for measuring visual intensity discrimination over a large range of intensities, with white light and with selected portions of the spectrum. With it measurements were made of the intensity DeltaI which is just perceptible when it is added for a short time to a portion of a field of intensity I to which the eye has been adapted. 2. For white and for all colors the fraction DeltaI/I decreases as I increases and reaches an asymptotic minimum value at high values of I. In addition, with white light the relation between DeltaI/I and I shows two sections, one at low intensities and the other at high intensities, the two being separated by an abrupt transition. These findings are contrary to the generally accepted measurements of Koenig and Brodhun; however, they confirm the recent work of Steinhardt, as well as the older work of Blanchard and of Aubert. The abrupt transition is in keeping with the Duplicity theory which attributes the two sections to the functions of the rods and cones respectively. 3. Measurements with five parts of the spectrum amplify these relationships in terms of the different spectral sensibilities of the rods and cones. With extreme red light the relation of DeltaI/I to I shows only a high intensity section corresponding to cone function, while with other colors the low intensity rod section appears and increases in extent as the light used moves toward the violet end of the spectrum. 4. Like most of the previously published data from various sources, the present numerical data are all described with precision by the theory which supposes that intensity discrimination is determined by the initial photochemical and chemical events in the rods and cones.
Comparison of Available Soil Nitrogen Assays in Control and Burned Forested Sites

The existence of several different methods for measuring net N mineralization and nitrification rates and indexing N availability has raised questions about the comparability of these methods. The authors compared in situ covered cores, in situ buried bags, aerobic laboratory incubations, and tension lysimetry on control and treated plots of a prescribed burn experiment in the southern Appalachians. Environmental influences were examined with soil moisture and temperature measurements. All methods detected significant differences in net N mineralization rates between treated and control plots; P = 0.04, 0.007, 0.001, and 0.07 for covered cores, buried bags, lab incubations, and lysimeters, respectively. Mean rates of N mineralization during the growing season were similar for the three soil incubation methods.
Optimization of LDPC-coded turbo CDMA systems

We consider the analysis and design of low-density parity-check (LDPC) codes for turbo multiuser detection in multipath code division multiple access (CDMA) channels. We develop techniques for computing the probability density function (pdf) of the extrinsic messages at the output of the soft-input soft-output (SISO) multiuser detectors as a function of the pdf of input extrinsic messages, user spreading codes, channel impulse responses, and signal-to-noise ratios. Of particular interest is the soft interference cancellation plus minimum mean square error (SIC-MMSE) multiuser detector, for which the pdf of the extrinsic messages can be characterized analytically. For the case of additive white Gaussian noise (AWGN) channels, the extrinsic messages can be well approximated as symmetric Gaussian distributed. For the case of asynchronous multipath fading channels, the extrinsic messages can be approximated by a mixture of symmetric Gaussian distributions. We show that the expectation-maximization (EM) algorithm can be used to compute the parameters of this mixture. Using these techniques, we are able to accurately compute the thresholds for LDPC codes and design good irregular LDPC codes. Simulation results are in good agreement with the computed thresholds, and the designed irregular LDPC codes outperform regular ones significantly.
Pressure structure functions and spectra for locally isotropic turbulence

Beginning with the known relationship between the pressure structure function and the fourth-order two-point correlation of velocity derivatives, we obtain a new theory relating the pressure structure function and spectrum to fourth-order velocity structure functions. This new theory is valid for all Reynolds numbers and for all spatial separations and wavenumbers. We do not use the joint Gaussian assumption that was used in previous theory. The only assumptions are local homogeneity, local isotropy, incompressibility, and use of the Navier-Stokes equation. Specific formulae are given for the mean-squared pressure gradient, the correlation of pressure gradients, the viscous range of the pressure structure function, and the pressure variance. Of course, pressure variance is a descriptor of the energy-containing range. Therefore, for any Reynolds number, the formula for pressure variance requires the more restrictive assumption of isotropy. For the case of large Reynolds numbers, formulae are given for the inertial range of the pressure structure function and spectrum and of the pressure-gradient correlation; these are valid on the basis of local isotropy, as are the formulae for mean-squared pressure gradient and the viscous range of the pressure structure function. Using the experimentally verified extension to fourth-order velocity structure functions of Kolmogorov’s theory, we obtain r4I3 and kp7/3 laws for the inertial range of the pressure structure function and spectrum. The modifications of these power laws to account for the effects of turbulence intermittency are also given. New universal constants are defined; these require experimental evaluation. The pressure structure function is sensitive to slight departures from local isotropy, implying stringent conditions on experimental data, but applicability of the previous theory is likewise constrained. The results are also sensitive to compressibility.
An Association between Bullying Behaviors and Alcohol Use among Middle School Students.

Although a high prevalence of bullying behaviors among adolescents has been documented, little is known about the association between bullying behaviors and alcohol use among perpetrators or victim...
Global controls of forest line elevation in the northern and southern hemispheres

We explored whether the independent evolu- tionary history of extratropical forests in the southern and northern hemispheres affects the temperature-elevation relationship of mountain forest lines. We compiled 115 forest line descrip- tions from the literature, covering the major extratropical mountain ranges of the world. We related forest line elevation to thermal regimes using mean annual temperature adjusted to sea level (MAT) and seasonal thermal amplitude (STA, mean of the warmest month minus the mean of the coldest) obtained from a global climate database. 2. Thermal variables explained 79% of the glo- bal variability of forest line elevation, which increased approximately 130 m for every 1 K of MAT and for every 2 K of STA. After considering STA, there was no significant effect of 'hemi- sphere' on forest line elevation. MAT-elevation relationships for sites with STA 30 K). Along a gradient of increasing STA and decreasing winter temperatures, forest lines were first dominated by evergreen broadleaf trees, followed by deciduous broadleaf species, ever- green conifers, and finally deciduous conifers. 4. Our results suggest that temperatures during the warm part of the year are the main control of forest line elevation in extratropical regions while temperatures during the cold part of the year affect the dominant life form of trees. There is a high degree of convergence in adaptation to mountain climates between trees species of both hemispheres. This convergence suggests that there is not a wide vacant altitudinal belt for introduced forest line species of the northern hemisphere into the southern hemisphere.
P-SH conversions in a flat-layered medium with anisotropy of arbitrary orientation

SUMMARY P-SH conversion is commonly observed in teleseismic P waves, and is often attributed to dipping interfaces beneath the receiver. Our modelling suggests an alternative explanation in terms of flat-layered anisotropy. We use reflectivity techniques to compute three-component synthetic seismograms in a 1-D anisotropic layered medium. For each layer of the medium, we prescribe values of seismic velocities and hexagonally symmetric anisotropy about a common symmetry axis of arbitrary orientation. A compressional wave in an anisotropic velocity structure suffers conversion to both SV-and SH-polarized shear waves, unless the axis of symmetry is everywhere vertical or the wave travels parallel to all symmetry axes. The P-SV conversion forms the basis of the widely used ‘receiver function’ technique. The P-SH conversion occurs at interfaces where one or both layers are anisotropic. A tilted axis of symmetry and a dipping interface in isotropic media produce similar amplitudes of both direct (P) and converted (Ps) phases, leaving the backazimuth variation of the P-Ps delay as the main discriminant. Seismic anisotropy with a tilted symmetry axis leads to complex synthetic seismograms in velocity models composed of just a few flat homogeneous layers. It is possible therefore to model observations of P coda with prominent transverse components with relatively simple 1-D velocity structures. Successful retrieval of salient model characteristics appears possible using multiple realizations of a genetic-algorithm (GA) inversion of P coda from several backazimuths. Using GA inversion, we determine that six P coda recorded at station ARU in central Russia are consistent with models that possess strong (> 10 per cent) anisotropy in the top 5 km and between 30 and 43 km depth. The symmetry axes are tilted, and appear aligned with the seismic anisotropy orientation in the mantle under ARU suggested by SKS splitting.
The location of the chloride binding sites in the oxygen-evolving complex of spinach Photosystem II

Abstract 35 Cl-NMR studies are presented here for spinach Photosystem II membranes inhibited by hydroxylamine (to remove Mn), Tris (to remove Mn and 18, 24 and 33 kDa polypeptides), and salt-washing (to remove 18 and 24 kDa; and 33 kDa polypeptides). Removal of Mn affects the 35 Cl-NMR binding curve only slightly, indicating that not all of the bound Mn is directly required for Cl-binding. Removal of both Mn and extrinsic polypeptides eliminates almost all of the Cl − -specific binding observable by NMR. Removal of the extrinsic 18 and 24 kDa polypeptides drastically changes the 35 Cl-NMR binding pattern; this effect is partially restored by the addition of 2 mM CaSO 4 , and, to a lesser extent, by the partial rebinding of the polypeptides. Existence of Cl − binding to the intrinsic polypeptides (e.g., D 1 D 2 ), with a peak at 0.5 mM Cl − , is shown in samples lacking 18, 24 and 33 kDa polypeptides. Thus, both intrinsic (i.e., on the D 1 D 2 membrane protein) and extrinsic (i.e., on the 33 kDa protein) binding sites for Cl − are suggested to exist.
Genetic contribution of SCARB1 variants to lipid traits in African Blacks: a candidate gene association study.

High-density lipoprotein cholesterol (HDL-C) exerts many anti-atherogenic properties including its role in reverse cholesterol transport (RCT). Scavenger receptor class B member 1 (SCARB1) plays a key role in RCT by selective uptake of HDL cholesteryl esters. We aimed to explore the genetic contribution of SCARB1 to affecting lipid levels in African Blacks from Nigeria. We resequenced 13 exons and exon-intron boundaries of SCARB1 in 95 individuals with extreme HDL-C levels using Sanger method. Then, we genotyped 147 selected variants (78 sequence variants, 69 HapMap tagSNPs, and 2 previously reported relevant variants) in the entire sample of 788 African Blacks using either the iPLEX Gold or TaqMan methods. A total of 137 successfully genotyped variants were further evaluated for association with major lipid traits. The initial gene-based analysis demonstrated evidence of association with HDL-C and apolipoprotein A-I (ApoA-I). The follow-up single-site analysis revealed nominal evidence of novel associations of nine common variants with HDL-C and/or ApoA-I (P < 0.05). The strongest association was between rs11057851 and HDL-C (P = 0.0043), which remained significant after controlling for multiple testing using false discovery rate. Rare variant association testing revealed a group of 23 rare variants (frequencies ≤1 %) associated with HDL-C (P = 0.0478). Haplotype analysis identified four SCARB1 regions associated with HDL-C (global P < 0.05). To our knowledge, this is the first report of a comprehensive association study of SCARB1 variations with lipid traits in an African Black population. Our results showed the consistent association of SCARB1 variants with HDL-C across various association analyses, supporting the role of SCARB1 in lipoprotein-lipid regulatory mechanism.
The complexity of software testing

The futility of using a general-purpose metric to characterise ‘the’ complexity of a program has recently been argued to support the design of specific metrics for the different stages of the software life-cycle. An analysis of the module testing activity is performed, providing evidence of the absurdity of all-purpose metrics, as well as a methodical means with which to measure testing complexity. Several standard metrics are seen to serve as component measures for the intricacies of testing. The methodology is applied to compare traditional and adaptive means of testing. It is shown that previous informal arguments asserting the superiority of adaptive methodologies are formally confirmed.
Self-regulation and Type A behavior

Abstract Several authors have suggested that self-regulation processes (i.e., high standards for success, self-criticism) underlie Type A behavior. The present three studies examine the self-regulation approach to Type A. Study I found that Jenkins Activity Survey (JAS) scores were correlated with trait measures of high standards for success, self-criticism, and positive expectancies for success. Further, this self-regulation profile was distinct from that associated with dysphoria. Study II replicated these self-regulation findings for the JAS and demonstrated similar though weaker relationships when Type A behavior was assessed with the Type A structured interview (SI). The Framingham Type A Scale (FTAS), however, was associated with dysphoric self-regulation processes. Study III examined the influence of situational standards for performance on self-regulation behaviors. JAS-defined Type As were less satisfied with their task performances than were Type Bs, but only when situational standards were lacking. FTAS-defined Type As were less satisfied than were Type Bs, but their dissatisfaction was constant across conditions. SI-defined Type A behavior was unrelated to situational self-regulation responses. Thus, these results suggest that the self-regulation approach may provide a useful account of the Type A behaviors assessed by the JAS, but also that it may not be an accurate model of other aspects of the Type A pattern.
Determining water use by trees and forests from isotopic, energy balance and transpiration analyses: the roles of tree size and hydraulic lift

Use of soil water and groundwater by open-grown Acer saccharum Marsh. (sugar maple) tree canopies and forests was estimated by measuring transpiration (E) rates using porometry, sap flow methods, and the Bowen ratio method. The Bowen ratio and sap flow methods showed the best agreement; porometer measurements scaled to whole canopies always underestimated E by 15-50%. Trees of different sizes showed very different rates of E. I hypothesized that these differences were due to the differential access of large and small trees to groundwater and soil water, respectively. Transpirational flux was partitioned between soil water and groundwater by tracing the water sources based on their hydrogen stable isotopic composition (deltaD). Soil water deltaD varied between -41 and -16 per thousand seasonally (May to September), whereas groundwater deltaD was -79 +/- 5 per thousand during the entire growing season. Daily transpiration rates of large (9-14 m tall) trees were significantly higher than those of small (3-5 m tall) trees (2.46-6.99 +/- 1.02-2.50 versus 0.69-1.80 +/- 0.39-0.67 mm day(-1)). Small trees also showed greater variation in E during the growing season than large trees. In addition, compared to the large trees, small trees demonstrated greater sensitivity to environmental factors that influence E, such as soil water deficits and increased evaporative demand. Over the entire growing season, large trees and forest stands composed of trees > 10 m tall transpired only groundwater. The high rates of water loss from large trees and older forests were likely a result of the influence of an enhanced "pool" of transpirational water in the upper soil layers caused by hydraulic lift (see Dawson 1993b). The hydraulically lifted water reservoir enabled large trees to use more potential transpirational water during daylight hours than small trees, leading to a greater total water flux. In contrast, small trees and forest stands composed of younger trees almost exclusively used soil water, except during two dry periods when their transpirational water was composed of between 7 and 17% groundwater. Thus groundwater discharge from sugar maple trees and forest stands of different sizes (ages) differs significantly, and large trees and older forest stands have a greater impact on the hydrologic balance of groundwater than small trees and younger forest stands. However, mixed stands (small and large trees) may have a greater overall impact on the regional hydrologic balance than old stands, because trees in mixed stands draw on both soil water and groundwater reservoirs and thus can substantially increase total water discharge on scales from tens to hundreds of hectares.
Changes in Abundance of Gopher Tortoise Burrows at Cape Sable, Florida

Abstract The southernmost population of Gopherus polyphemus (Gopher Tortoises) occurs at Cape Sable, FL. The burrows of this population were surveyed in 1979 using strip transects to estimate Gopher Tortoise burrow density. We present data from a 1990 strip-transect survey and a 2001 line-transect survey of burrows for comparison. We found a significantly lower density of active burrows and a significantly higher density of abandoned burrows in 2001 compared to 1979 and 1990, but the overall density of burrows did not differ significantly over time. The distribution of burrow widths in 2001 was not significantly different from the 1982 distribution, and the bimodal pattern suggests that reproduction has occurred at the site. The 76% decline of active burrows at the site suggests that Gopher Tortoises have been subject to mortality. Reduction of habitat quality and tropical storms are possible explanations for the apparent decline in the Gopher Tortoise population at Cape Sable, but more monitoring is requ...
Molecular Signaling Mechanisms of Natural and Synthetic Retinoids for Inhibition of Pathogenesis in Alzheimer’s Disease

Retinoids, which are vitamin A derivatives, interact through retinoic acid receptors (RARs) and retinoid X receptors (RXRs) and have profound effects on several physiological and pathological processes in the brain. The presence of retinoic acid signaling is extensively detected in the adult central nervous system, including the amygdala, cortex, hypothalamus, hippocampus, and other brain areas. Retinoids are primarily involved in neural patterning, differentiation, and axon outgrowth. Retinoids also play a key role in the preservation of the differentiated state of adult neurons. Impairment in retinoic acid signaling can result in neurodegeneration and progression of Alzheimer's disease (AD). Recent studies demonstrated severe deficiencies in spatial learning and memory in mice during retinoic acid (vitamin A) deprivation indicating its significance in preserving memory function. Defective cholinergic neurotransmission plays an important role in cognitive deficits in AD. All-trans retinoic acid is known to enhance the expression and activity of choline acetyltransferase in neuronal cell lines. Activation of RAR and RXR is also known to impede the pathogenesis of AD in mice by inhibiting accumulation of amyloids. In addition, retinoids have been shown to inhibit the expression of chemokines and pro-inflammatory cytokines in microglia and astrocytes, which are activated in AD. In this review article, we have described the chemistry and molecular signaling mechanisms of natural and synthetic retinoids and current understandings of their therapeutic potentials in prevention of AD pathology.
Water for Producing Food for Basic Consumption – Guaranteed by the Right to Water or Food?

The human right to water has been criticised for being biased towards urban areas due to its focus on water for personal and domestic uses. It has been pointed out that people living in rural areas often require water not only to satisfy their personal and domestic needs, but also for other uses relating to the broader goals of poverty reduction and livelihood security, such as food production and income generation. It could be argued that the focus of the right to water on personal and domestic uses bypasses the reality of people living in rural areas, who require water for multiple uses. This raises the question as to whether such water uses are guaranteed by the human right to water or other human rights. This chapter addresses one aspect of this question from the perspective of international human rights law and focuses on water for food production for basic consumption, in particular, subsistence agriculture.
Sixty Years of African Studies at Howard University

Howard serves as an institution of higher education for people of African descent with an enduring commitment to education and research. In defining its primary mission of upholding social justice, a former president of the university, James Cheek noted that “some universities may claim to be neutral, as Harvard does, on the great moral and social issues in our society, but not Howard University.” To underscore the university’s broader mission he stated: “Our institution is in the business of not only educating but also liberating; of not only discovering but also reconstructing; we are in the business of undoing the yoke of bondage.” And at the core of this mission have been Africa and the African World. Scholars in the institution laid down the building blocks of the African Studies interdisciplinary paradigm. Among the pioneers in the field at Howard was Melvin Herskovits who took part in the 1929 Howard sponsored a conference on Africa. Decades of teaching, research and engagements in issues pertaining to Africa culminated in the formal establishment in 1953 of an African Studies research program. In 1969 the academic commitment to the area was elevated to a graduate level making Howard the first university to offer a Ph.D. in African Studies. Sixty years of African Studies at Howard is being celebrated to honor this rich tradition and renew commitments to the field for the coming decades. The panel seeks to share the legacy and continued vision in a scholarly discourse with the esteemed members of the association.
Measuring the Dispersion of Cancer Mortality Rates by the Interquartile Range

Inspection of maps from the recently-published Atlases of U.S. Cancer Mortality 1,2 suggested that mortality rates for many cancer sites were becoming more geographically homogeneous over time. From 1950 to 1980 rates for the more common tumors (e.g., breast cancer) seemed to increase significantly faster than the overall U.S. rate in areas that had had relatively low rates during the 1950s. We sought to verify this visual impression by quantifying the degree of dispersion of these mortality rates in a manner that would permit comparison of rate variability (a) over time for a particular cancer site, and (b) among cancer sites for the latest time period. It should be emphasized that we were interested in assessing the range or distributional variation of the mortality rates and have not attempted to measure spatial autocorrelation or aggregation.