778 research outputs found
Site Characterization Using Integrated Imaging Analysis Methods on Satellite Data of the Islamabad, Pakistan, Region
We develop an integrated digital imaging analysis approach to produce a first-approximation site characterization map for Islamabad, Pakistan, based on remote-sensing data. We apply both pixel-based and object-oriented digital imaging analysis methods to characterize detailed (1:50,000) geomorphology and geology from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery. We use stereo-correlated relative digital elevation models (rDEMs) derived from ASTER data, as well as spectra in the visible near-infrared (VNIR) to thermal infrared (TIR) domains. The resulting geomorphic units in the study area are classified as mountain (including the Margala Hills and the Khairi Murat Ridge), piedmont, and basin terrain units. The local geologic units are classified as limestone in the Margala Hills and the Khairi Murat Ridge and sandstone rock types for the piedmonts and basins. Shear-wave velocities for these units are assigned in ranges based on established correlations in California. These ranges include Vs30-values to be greater than 500 m/sec for mountain units, 200–600 m/sec for piedmont units, and less than 300 m/sec for basin units. While the resulting map provides the basis for incorporating site response in an assessment of seismic hazard for Islamabad, it also demonstrates the potential use of remote-sensing data for site characterization in regions where only limited conventional mapping has been done
Invertebrate Diet of Breeding and Nonbreeding Crested Caracaras (Caracara cheriway) in Florida
We compared the invertebrate component of the diet of breeding and nonbreeding northern Crested Caracaras (Caracara cheriway) during the breeding season, January through April, in Florida, using pellet analysis. Pellets from breeding adults were collected at active nests and pellets of nonbreeding caracaras were collected from beneath a communal roost. During the breeding season, breeding and nonbreeding caracaras consumed invertebrate prey from a minimum of 61 genera and a total of 33 families from eight orders. Nonbreedingcaracaras consumed greater total numbers of invertebrates, more different prey types, and a greater diversity of invertebrates than did breeding caracaras. Pellets of nonbreeding caracaras contained more invertebrates per pellet, and carrion insects occurred more frequently in pellets of nonbreeding caracaras. Our findings suggest hypotheses regarding the possible role of intraspecific competition in the use of particular habitats and food resources by breeding and nonbreeding caracaras in Florida. Breeding pairs of caracaras are highly territorial and primarily feed nestlings larger-sized vertebrate prey, and field observations indicated that territorial adults can exclude young (nonbreeding) birds from their breeding areas; thus, diet differences may reflect social structure within this population. If pairs of breeding adults exclude conspecifics from important food resources or foraging habitats, nonbreeders may hunt arthropods or rely on carrion by necessity, especially if nonbreeders occur in suboptimal habitat in which other prey are less available
Overexpression screen of interferon-stimulated genes identifies RARRES3 as a restrictor of Toxoplasma gondii infection
Toxoplasma gondii is an important human pathogen infecting an estimated one in three people worldwide. The cytokine interferon gamma (IFNγ) is induced during infection and is critical for restricting T. gondii growth in human cells. Growth restriction is presumed to be due to the induction of interferon-stimulated genes (ISGs) that are upregulated to protect the host from infection. Although there are hundreds of ISGs induced by IFNγ, their individual roles in restricting parasite growth in human cells remain somewhat elusive. To address this deficiency, we screened a library of 414 IFNγ induced ISGs to identify factors that impact T. gondii infection in human cells. In addition to IRF1, which likely acts through the induction of numerous downstream genes, we identified RARRES3 as a single factor that restricts T. gondii infection by inducing premature egress of the parasite in multiple human cell lines. Overall, while we successfully identified a novel IFNγ induced factor restricting T. gondii infection, the limited number of ISGs capable of restricting T. gondii infection when individually expressed suggests that IFNγ-mediated immunity to T. gondii infection is a complex, multifactorial process
Fluxional η^3-Allyl Derivatives of ansa-Scandocenes and an ansa-Yttrocene. Measurements of the Barriers for the η^3 to η^1 Process as an Indicator of Olefin Binding Energy to d^0 Metallocenes
Variable-temperature ^1H NMR spectroscopy indicates fluxional behavior for a number of group 3 metallocene allyl complexes. Spectral simulations and line shape analyses for the variable-temperature spectra indicate an allyl rearrangement mechanism involving rate-determining carbon−carbon double-bond dissociation from the metal center, i.e. an η^3 to η^1 change in coordination. Activation barriers to olefin dissociation have been determined for (η^5-C_5Me_5)_2Sc(η^3-C^3H^5), meso-Me^2Si(η^5-3-CMe^3-C_5H_3)_2Sc(η^3-C_3H_5), meso-Me_2Si[η^5-2,4-(CHMe_2)_2-C_5H_2]_2Sc(η^3-C_3H_5), meso-Me_2Si{η^5-3-[2-(2-Me)-adamantyl]-C_5H_3}_2Sc(η^3-C_3H_5), meso-Me_2Si{η^5-3-[2-(2-Me)-adamantyl]-C_5H_3}_2Y(η^3-C_3H_5), rac-Me_2Si[η^5-2,4-(CHMe_2)_2-C_5H_2]_2Sc(η^3-C_3H_5)), and R-(C_(20)H_(12)O_2)Si(η^5-2-SiMe_3-4-CMe_3-C_5H_2)_2Sc(η^3-C_3H_5): ΔG^⧧ = 11−16 kcal mol^(-1) at ca. 300−350 K. Donor solvents do not significantly affect the rate of olefin dissociation. A second rearrangement mechanism that involves 180° rotation of the η^3-C_3H_5 moiety has been found to operate in those metallocenes whose ancillary ligand arrays adopt rigid meso geometries. Line shape analysis indicates that the rate of η^3-C_3H_5 rotation is generally more than 1 order of magnitude faster than olefin dissociation for a given meso metallocene. The data do not allow unambiguous assessments of the mechanism(s) for the fluxional behavior for the allyl derivatives of the racemic metallocenes. An X-ray structure determination for rac-Me_2Si[η^5-C_5H_2-2,4-(CHMe_2)_2]_2Sc(η^3-C_3H_5) has been carried out
Hematopoietic Cell Transplant and Use of Massage for Improved Symptom Management: Results from a Pilot Randomized Control Trial
Background. Pediatric hematopoietic cell transplant (HCT) is a lifesaving treatment that often results in physical and psychological discomfort. An acupressure-massage intervention may improve symptom management in this setting.
Methods. This randomized controlled pilot trial compared a combined massage-acupressure intervention to usual care. Children were offered three practitioner-provided sessions per week throughout hospitalization. Parents were trained to provide additional acupressure as needed. Symptoms were assessed using nurses' reports and two questionnaires, the behavioral affective and somatic experiences scale and the Peds quality of life cancer module.
Results. We enrolled 23 children, ages 5 to 18. Children receiving the intervention reported fewer days of mucositis (Hedges' g effect size ES = 0.63), lower overall symptom burden (ES = 0.26), feeling less tired and run-down (ES = 0.86), having fewer moderate/severe symptoms of pain, nausea, and fatigue (ES = 0.62), and less pain (ES = 0.42). The intervention group showed trends toward increasing contentness/serenity (ES = +0.50) and decreasing depression (ES = −0.45), but not decreased anxiety (ES = +0.42). Differences were not statistically significant.
Discussion. Feasibility of studying massage-acupressure was established in children undergoing HCT. Larger studies are needed to test the efficacy of such interventions in reducing HCT-associated symptoms in children
Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
<p>Abstract</p> <p>Background</p> <p>Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the TAG biosynthesis pathway. Of note, overexpression of <it>DGAT1 </it>results in substantial increases in oil content and seed size. To further analyze the global consequences of manipulating <it>DGAT1 </it>levels during seed development, a concerted transcriptome and metabolome analysis of transgenic <it>B. napus </it>prototypes was performed.</p> <p>Results</p> <p>Using a targeted <it>Brassica </it>cDNA microarray, about 200 genes were differentially expressed in two independent transgenic lines analyzed. Interestingly, 24–33% of the targets showing significant changes have no matching gene in <it>Arabidopsis </it>although these represent only 5% of the targets on the microarray. Further analysis of some of these novel transcripts indicated that several are inducible by ABA in microspore-derived embryos. Of the 200 <it>Arabidopsis </it>genes implicated in lipid biology present on the microarray, 36 were found to be differentially regulated in DGAT transgenic lines. Furthermore, kinetic reverse transcriptase Polymerase Chain Reaction (k-PCR) analysis revealed up-regulation of genes encoding enzymes of the Kennedy pathway involved in assembly of TAGs. Hormone profiling indicated that levels of auxins and cytokinins varied between transgenic lines and untransformed controls, while differences in the pool sizes of ABA and catabolites were only observed at later stages of development.</p> <p>Conclusion</p> <p>Our results indicate that the increased TAG accumulation observed in transgenic <it>DGAT1 </it>plants is associated with modest transcriptional and hormonal changes during seed development that are not limited to the TAG biosynthesis pathway. These might be associated with feedback or feed-forward effects due to altered levels of DGAT1 activity. The fact that a large fraction of significant amplicons have no matching genes in <it>Arabidopsis </it>compromised our ability to draw concrete inferences from the data at this stage, but has led to the identification of novel genes of potential interest.</p
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Real-Time Increased Detection of Neoplastic Tissue in Barrett’s Esophagus with Probe-Based Confocal Laser Endomicroscopy: Final Results of an International Multicenter, Prospective, Randomized, Controlled Trial
BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) allows real-time detection of neoplastic Barrett's esophagus (BE) tissue. However, the accuracy of pCLE in real time has not yet been extensively evaluated. OBJECTIVE: To compare the sensitivity and specificity of pCLE in addition to high-definition white-light endoscopy (HD-WLE) with HD-WLE alone for the detection of high-grade dysplasia (HGD) and early carcinoma (EC) in BE. DESIGN: International, prospective, multicenter, randomized, controlled trial. SETTING: Five tertiary referral centers. PATIENTS: A total of 101 consecutive BE patients presenting for surveillance or endoscopic treatment of HGD/EC. INTERVENTIONS: All patients were examined by HD-WLE, narrow-band imaging (NBI), and pCLE, and the findings were recorded before biopsy samples were obtained. The order of HD-WLE and NBI was randomized and performed by 2 independent, blinded endoscopists. All suspicious lesions on HD-WLE or NBI and 4-quadrant random locations were documented. These locations were examined by pCLE, and a presumptive diagnosis of benign or neoplastic (HGD/EC) tissue was made in real time. Finally, biopsies were taken from all locations and were reviewed by a central pathologist, blinded to endoscopic and pCLE data. MAIN OUTCOME MEASUREMENTS: Diagnostic characteristics of pCLE. RESULTS: The sensitivity and specificity for HD-WLE were 34.2% and 92.7%, respectively, compared with 68.3% and 87.8%, respectively, for HD-WLE or pCLE (P = .002 and P < .001, respectively). The sensitivity and specificity for HD-WLE or NBI were 45.0% and 88.2%, respectively, compared with 75.8% and 84.2%, respectively, for HD-WLE, NBI, or pCLE (P = .01 and P = .02, respectively). Use of pCLE in conjunction with HD-WLE and NBI enabled the identification of 2 and 1 additional HGD/EC patients compared with HD-WLE and HD-WLE or NBI, respectively, resulting in detection of all HGD/EC patients, although not statistically significant. LIMITATIONS: Academic centers with enriched population. CONCLUSIONS: pCLE combined with HD-WLE significantly improved the ability to detect neoplasia in BE patients compared with HD-WLE. This may allow better informed decisions to be made for the management and subsequent treatment of BE patients. (Clinical trial registration number: NCT00795184.)
Randomized Trial of Letrozole Following Tamoxifen as Extended Adjuvant Therapy in Receptor-Positive Breast Cancer: Updated Findings from NCIC CTG MA.17
Background: Most recurrences in women with breast cancer receiving 5 years of adjuvant tamoxifen occur after 5 years. The MA.17 trial, which was designed to determine whether extended adjuvant therapy with the aromatase inhibitor letrozole after tamoxifen reduces the risk of such late recurrences, was stopped early after an interim analysis showed that letrozole improved disease-free survival. This report presents updated findings from the trial. Methods: Postmenopausal women completing 5 years of tamoxifen treatment were randomly assigned to a planned 5 years of letrozole (n = 2593) or placebo (n = 2594). The primary endpoint was disease-free survival (DFS); secondary endpoints included distant disease-free survival, overall survival, incidence of contralateral tumors, and toxic effects. Survival was examined using Kaplan-Meier analysis and log-rank tests. Planned subgroup analyses included those by axillary lymph node status. All statistical tests were two-sided. Results: After a median follow-up of 30 months (range = 1.5-61.4 months), women in the letrozole arm had statistically significantly better DFS and distant DFS than women in the placebo arm (DFS: hazard ratio [HR] for recurrence or contralateral breast cancer = 0.58, 95% confidence interval [CI] = 0.45 to 0.76; P<.001; distant DFS: HR = 0.60, 95% CI = 0.43 to 0.84; P = .002). Overall survival was the same in both arms (HR for death from any cause = 0.82, 95% CI = 0.57 to 1.19; P = .3). However, among lymph node-positive patients, overall survival was statistically significantly improved with letrozole (HR = 0.61, 95% CI = 0.38 to 0.98; P = .04). The incidence of contralateral breast cancer was lower in women receiving letrozole, but the difference was not statistically significant. Women receiving letrozole experienced more hormonally related side effects than those receiving placebo, but the incidences of bone fractures and cardiovascular events were the same. Conclusion: Letrozole after tamoxifen is well-tolerated and improves both disease-free and distant disease-free survival but not overall survival, except in node-positive patient
Negative emotional stimuli reduce contextual cueing but not response times in inefficient search
In visual search, previous work has shown that negative stimuli narrow the focus of attention and speed reaction times (RTs). This paper investigates these two effects by first asking whether negative emotional stimuli narrow the focus of attention to reduce the learning of a display context in a contextual cueing task and, second, whether exposure to negative stimuli also reduces RTs in inefficient search tasks. In Experiment 1, participants viewed either negative or neutral images (faces or scenes) prior to a contextual cueing task. In a typical contextual cueing experiment, RTs are reduced if displays are repeated across the experiment compared with novel displays that are not repeated. The results showed that a smaller contextual cueing effect was obtained after participants viewed negative stimuli than when they viewed neutral stimuli. However, in contrast to previous work, overall search RTs were not faster after viewing negative stimuli (Experiments 2 to 4). The findings are discussed in terms of the impact of emotional content on visual processing and the ability to use scene context to help facilitate search
Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model
Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures
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