Non-native shrub species in the genus Tamarix (saltcedar, tamarisk) have colonized hundreds of thousands of hectares of floodplains, reservoir margins, and other wetlands in western North America. ...Many resource managers seek to reduce saltcedar abundance and control its spread to increase the flow of water in streams that might otherwise be lost to evapotranspiration, to restore native riparian (streamside) vegetation, and to improve wildlife habitat. However, increased water yield might not always occur and has been substantially lower than expected in water salvage experiments, the potential for successful revegetation is variable, and not all wildlife taxa clearly prefer native plant habitats over saltcedar. As a result, there is considerable debate surrounding saltcedar control efforts. We review the literature on saltcedar control, water use, wildlife use, and riparian restoration to provide resource managers, researchers, and policy-makers with a balanced summary of the state of the science. To best ensure that the desired outcomes of removal programs are met, scientists and resource managers should use existing information and methodologies to carefully select and prioritize sites for removal, apply the most appropriate and cost-effective control methods, and then rigorously monitor control efficacy, revegetation success, water yield changes, and wildlife use.
Ig heavy chain class switch recombination (CSR) involves a recombination/deletion mechanism that exchanges the expressed CHgene with a downstream CHgene. CSR is mediated by highly repetitive switch ...(S) region sequences and requires the activation-induced deaminase (AID). The S region 5′ of the Cμ gene (Sμ) can undergo high-frequency internal deletions in normal B cells and B cell lines activated for CSR, although the relationship of these deletions and CSR has not been elucidated. In this study, we introduced constitutively transcribed Sμ or Sγ2b regions into a pro-B cell line that can be activated for AID expression, CSR, and endogenous Sμ deletions. We find that randomly integrated S region transcription units in these cells also undergo increased levels of internal rearrangements after cellular activation, indicating that the deletion process is independent of location within the Ig heavy chain locus and potentially AID-promoted. To test the latter issue, we generated hybridomas from wild-type and AID-deficient activated B cells and assayed them for internal Sμ deletions and S region mutations. These studies demonstrated that efficient intra-S region recombination depends on AID expression and that internal S region deletions are accompanied by frequent mutations, indicating that most S region deletions occur by the same mechanism as CSR.
The study examined the importance of the retrosplenial cortex for the incidental learning of the spatial arrangement of distinctive features within a scene. In a modified Morris water-maze, rats ...spontaneously learnt the location of an escape platform prior to swimming to that location. For this, rats were repeatedly placed on a submerged platform in one corner of either a rectangular (Experiment 1) or square (Experiments 2, 3) pool with walls of different appearance. The rats were then released in the center of the pool for their first test trial. In Experiment 1, the correct corner and its diagonally opposite partner (also correct) were specified by the geometric properties of the pool. Rats with retrosplenial lesions took longer to first reach a correct corner, subsequently showing an attenuated preference for the correct corners. A reduced preference for the correct corner was also found in Experiment 2, when platform location was determined by the juxtaposition of highly salient visual cues (black vs. white walls). In Experiment 3, less salient visual cues (striped vs. white walls) led to a robust lesion impairment, as the retrosplenial lesioned rats showed no preference for the correct corner. When subsequently trained actively to swim to the correct corner over successive trials, retrosplenial lesions spared performance on all three discriminations. The findings not only reveal the importance of the retrosplenial cortex for processing various classes of visuospatial information but also highlight a broader role in the incidental learning of the features of a spatial array, consistent with the translation of scene information.
The IBM POWER6(TM) microprocessor is a 790 million-transistor chip that runs at a clock frequency of greater than 4 GHz. The complexity and size of the POWER6 microprocessor, together with its high ...operating frequency, present a number of significant challenges. This paper describes the physical design and design methodology of the POWER6 processor. Emphasis is placed on aspects of the design methodology, technology, clock distribution, integration, chip analysis, power and performance, random logic macro (RLM), and design data management processes that enabled the design to be completed and the project goals to be met. PUBLICATION ABSTRACT
abstract
Enteroaggregative Escherichia coli (EAEC) is emerging as a significant diarrheal pathogen in multiple population groups. Although most commonly associated with pediatric diarrhea in ...developing countries, EAEC is also linked to diarrhea in adults including HIV‐positive patients and travelers and has been a cause of food‐borne outbreaks in the industrialized world. Current data suggest that one set of virulence elements is not associated with all EAEC strains, but that combinations of multiple factors prevail. Pathogenesis is believed to be initiated with adherence to the terminal ileum and colon in an aggregative, stacked‐brick‐type pattern by means of one of several different hydrophobic aggregative adherence fimbriae. Some strains of EAEC may then elaborate cytotoxins including the plasmid‐encoded toxin and the enterotoxins, EAST1 and ShET1. An AraC homolog termed AggR regulates several genes contributing to fimbrial biogenesis in ‘typical EAEC strains’. AggR has now also been shown to regulate genes on a chromosomal island. Sequencing of the EAEC type strain 042 completed at the Sanger Center has revealed two other chromosomal islands that are being explored for their pathogenetic potential. This article reviews these virulence elements and presents on‐going areas of research in EAEC pathogenesis.
We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance predicts outcomes in patients with transposition of the great arteries post atrial ...redirection surgery. These patients have a systemic right ventricle (RV) and are at risk of arrhythmia, premature RV failure, and sudden death.
Fifty-five patients (aged 27±7 years) underwent LGE cardiovascular magnetic resonance and were followed for a median 7.8 (interquartile range, 3.8-9.6) years in a prospective single-center cohort study. RV LGE was present in 31 (56%) patients. The prespecified composite clinical end point comprised new-onset sustained tachyarrhythmia (atrial/ventricular) or decompensated heart failure admission/transplantation/death. Univariate predictors of the composite end point (n=22 patients; 19 atrial/2 ventricular tachyarrhythmia, 1 death) included RV LGE presence and extent, RV volumes/mass/ejection fraction, right atrial area, peak Vo(2), and age at repair. In bivariate analysis, RV LGE presence was independently associated with the composite end point (hazard ratio, 4.95 95% confidence interval, 1.60-15.28; P=0.005), and only percent predicted peak Vo(2) remained significantly associated with cardiac events after controlling for RV LGE (hazard ratio, 0.80 95% confidence interval, 0.68-0.95; P=0.009/5%). In 8 of 9 patients with >1 event, atrial tachyarrhythmia, itself a known risk factor for mortality, occurred first. There was agreement between location and extent of RV LGE at in vivo cardiovascular magnetic resonance and histologically documented focal RV fibrosis in an explanted heart. There was RV LGE progression in a different case restudied for clinical indications.
Systemic RV LGE is strongly associated with adverse clinical outcome especially arrhythmia in transposition of the great arteries, thus LGE cardiovascular magnetic resonance should be incorporated in risk stratification of these patients.
Anderson-Fabry Disease (AFD), an X-linked disorder of sphingolipid metabolism, is a cause of idiopathic left ventricular hypertrophy but the mechanism of hypertrophy is poorly understood. Gadolinium ...enhanced cardiovascular magnetic resonance can detect focal myocardial fibrosis. We hypothesised that hyperenhancement would be present in AFD.
Eighteen males (mean 43+/-14 years) and eight female heterozygotes (mean 48+/-12 years) with AFD underwent cine and late gadolinium cardiovascular magnetic resonance. Nine male (50%) had myocardial hyperenhancement ranging from 3.4% to 20.6% (mean 7.7+/-5.7%) of total myocardium; in males, percentage hyperenhancement related to LV mass index (r=0.78, P=0.0002) but not to ejection fraction or left ventricular volumes. Lesser hyperenhancement was also found in four (50%) heterozygous females (mean 4.6%). In 12 (92%) patients with abnormal gadolinium uptake, hyperenhancement occurred in the basal infero-lateral wall where, unlike myocardial infarction, it was not sub-endocardial. In two male patients with severe LVH (left ventricular hypertrophy) and systolic impairment there was additional hyperenhancement in other myocardial segments.
These observations suggests that myocardial fibrosis occurs in AFD and may contribute to the hypertrophy and the natural history of the disease.
We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg ...super(2) of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of Deltaz/(1 + z) - 0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z = 1.35 with a median of z sub(med) = 0.57. Approximately 18% of the sample with measured redshifts lies at z > 0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance xi > 5(xi > 4.5) is > or =, slanted95% (> or =, slanted70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples.
We experimentally observed optical rogue wave statistics during high power femtosecond pulse filamentation in air. We characterized wavelength-dependent intensity fluctuations across 300 nm broadband ...filament spectra generated by pulses with several times the critical power for filamentation. We show how the statistics vary from a near-Gaussian distribution in the vicinity of the pump to a long tailed "L-shaped" distribution at the short wavelength and long wavelength edges. The results are interpreted in terms of pump noise transfer via self-phase modulation.
Historically, the no-man's land created by human warfare often protected wildlife and habitats by limiting human incursions and human population densities within disputed territories. Relatively few ...examples of this phenomenon have been identified in conjunction with recent and ongoing wars in developing countries, however. Modern wars and civil strife are typically associated with detrimental effects on wildlife and wildlife habitats. Most cited instances of contemporary war-zone refuges refer to military security areas that are functionally and geographically distinct from actual battlefields or areas subject to armed civil conflicts. The disappearance of the war-zone refuge effect is attributable to modern trends in the scale, intensity, or technologies associated with military conflicts and violent civil strife. Munitions and chemical agents exert both immediate and residual effects, direct and indirect, on wildlife and habitats. Overharvesting of wildlife and vegetation in conflict zones exacerbates existing constraints on the access to natural resources, threatening both the resource base and the livelihoods of local communities dependent on these resources. Socioeconomic studies have identified causative linkages between environmental degradation and violent civil strife, with the scarcity of natural resources fostering the emergence of war and civil conflicts in developing countries. Wars and civil strife create positive feedback that reinforces and amplifies interactions between and among ecosystem vulnerability, resource availability, and violent conflict. Strong and flexible partnerships between local communities, nongovernmental organizations, and international institutions may be a critical factor in mitigating the effects of war on wildlife by helping to maintain continuity in conservation efforts during periods of political instability.
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