948 resultados para gravitational lensing: strong
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We report the first measurement of charmed-hadron (D(0)) production via the hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N(bin), from p+p to central Au+Au collisions. The D(0) meson yields in central Au + Au collisions are strongly suppressed compared to those in p+p scaled by N(bin), for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p(T) is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.
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This study tested whether myocardial extracellular volume (ECV) is increased in patients with hypertension and atrial fibrillation (AF) undergoing pulmonary vein isolation and whether there is an association between ECV and post-procedural recurrence of AF. Hypertension is associated with myocardial fibrosis, an increase in ECV, and AF. Data linking these findings are limited. T1 measurements pre-contrast and post-contrast in a cardiac magnetic resonance (CMR) study provide a method for quantification of ECV. Consecutive patients with hypertension and recurrent AF referred for pulmonary vein isolation underwent a contrast CMR study with measurement of ECV and were followed up prospectively for a median of 18 months. The endpoint of interest was late recurrence of AF. Patients had elevated left ventricular (LV) volumes, LV mass, left atrial volumes, and increased ECV (patients with AF, 0.34 ± 0.03; healthy control patients, 0.29 ± 0.03; p < 0.001). There were positive associations between ECV and left atrial volume (r = 0.46, p < 0.01) and LV mass and a negative association between ECV and diastolic function (early mitral annular relaxation [E'], r = -0.55, p < 0.001). In the best overall multivariable model, ECV was the strongest predictor of the primary outcome of recurrent AF (hazard ratio: 1.29; 95% confidence interval: 1.15 to 1.44; p < 0.0001) and the secondary composite outcome of recurrent AF, heart failure admission, and death (hazard ratio: 1.35; 95% confidence interval: 1.21 to 1.51; p < 0.0001). Each 10% increase in ECV was associated with a 29% increased risk of recurrent AF. In patients with AF and hypertension, expansion of ECV is associated with diastolic function and left atrial remodeling and is a strong independent predictor of recurrent AF post-pulmonary vein isolation.
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By comparing the SEED and Pfam functional profiles of metagenomes of two Brazilian coral species with 29 datasets that are publicly available, we were able to identify some functions, such as protein secretion systems, that are overrepresented in the metagenomes of corals and may play a role in the establishment and maintenance of bacteria-coral associations. However, only a small percentage of the reads of these metagenomes could be annotated by these reference databases, which may lead to a strong bias in the comparative studies. For this reason, we have searched for identical sequences (99% of nucleotide identity) among these metagenomes in order to perform a reference-independent comparative analysis, and we were able to identify groups of microbial communities that may be under similar selective pressures. The identification of sequences shared among the metagenomes was found to be even better for the identification of groups of communities with similar niche requirements than the traditional analysis of functional profiles. This approach is not only helpful for the investigation of similarities between microbial communities with high proportion of unknown reads, but also enables an indirect overview of gene exchange between communities.
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Essential oils (EO) obtained from twenty medicinal and aromatic plants were evaluated for their antimicrobial activity against the oral pathogens Candida albicans, Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus sanguis and Streptococcus mitis. The antimicrobial activity of the EO was evaluates by microdilution method determining Minimal Inhibitory Concentration. Chemical analysis of the oils compounds was performed by Gas chromatography-mass spectrometry (CG-MS). The most active EO were also investigated as to their actions on the biolfilm formation. The most of the essential oils (EO) presented moderate to strong antimicrobial activity against the oral pathogens (MIC--Minimal Inhibitory Concentrations values between 0.007 and 1.00 mg/mL). The essential oil from Coriandrum sativum inhibited all oral species with MIC values from 0.007 to 0.250 mg/mL, and MBC/MFC (Minimal Bactericidal/Fungicidal Concentrations) from 0.015 to 0.500 mg/mL. On the other hand the essential oil of C. articulatus inhibited 63.96% of S. sanguis biofilm formation. Through Scanning Eletronic Microscopy (SEM) images no changes were observed in cell morphology, despite a decrease in biofilm formation and changes on biofilm structure. Chemical analysis by Gas Chromatography-Mass Spectrometry (GC-MS) of the C. sativum essential oil revealed major compounds derivatives from alcohols and aldehydes, while Cyperus articulatus and Aloysia gratissima (EOs) presented mono and sesquiterpenes. In conclusion, the crude oil from C. articulatus exhibited the best results of antimicrobial activity e ability to control biofilm formation. The chemical analysis showed the presence of terpenes and monoterpenes such as a-pinene, a-bulnesene and copaene. The reduction of biofilms formation was confirmed from SEM images. The results of this research shows a great potential from the plants studied as new antimicrobial sources.
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A randomized controlled trial study was performed to evaluate the efficacy of transcutaneous tibial nerve stimulation (TTNS) and sham TTNS, in patients with Parkinson disease (PD) with lower urinary tract symptoms (LUTS). Randomized controlled trial. Thirteen patients with a diagnosis of PD and bothersome LUTS were randomly allocated to one of the following groups: Group I: TTNS group (n = 8) and group II: Sham group (n = 5). Both groups attended twice a week during 5 weeks; each session lasted 30 minutes. Eight patients received TTNS treatment and 5 subjects allocated to group II were managed with sham surface electrodes that delivered no electrical stimulation. Assessments were performed before and after the treatment; they included a 3-day bladder diary, Overactive Bladder Questionnaire (OAB-V8), and the International Consultation on Incontinence Quality of Life Questionnaire Short Form (ICIQ-SF), and urodynamic evaluation. Following 5 weeks of treatment, patients allocated to TTNS demonstrated statistically significant reductions in the number of urgency episodes (P = .004) and reductions in nocturia episodes (P < .01). Participants allocated to active treatment also showed better results after treatment in the OAB-V8 and ICIQ-SF scores (P < .01, respectively). Urodynamic testing revealed that patients in the active treatment group showed improvements in intravesical volume at strong desire to void (P < .05) and volume at urgency (P < .01) when compared to subjects in the sham treatment group. These findings suggest that TTNS is effective in the treatment of LUTS in patients with PD, reducing urgency and nocturia episodes and improving urodynamic parameters as well as symptom scores measured by the OAB-V8 and health-related quality-of-life scores measured by the ICIQ-SF.
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The aim of this study was to analyze the effects of dual tasking on obstacle crossing during walking by individuals with Alzheimer's disease (AD) and by healthy older people. Thirty four elderly individuals (16 healthy subjects and 18 individuals with AD) were recruited to participate in this study. Three AD individuals and one control participant were excluded due to exclusion criteria. The participants were instructed to walk barefoot at their own speed along an 8 m long pathway. Each participant performed five trials for each condition (unobstructed walking, unobstructed walking with dual tasking, and obstacle crossing during walking with dual tasking). The trials were completely randomized for each participant. The mid-pathway stride was measured in the unobstructed walking trials and the stride that occurred during the obstacle avoidance was measured in the trials that involved obstacle crossing. The behavior of the healthy elderly subjects and individuals with AD was similar for obstacle crossing during walking with dual tasking. Both groups used the posture first strategy to prioritize stability and showed decreased attention to executive tasking while walking. Additionally, AD had a strong influence on the modifications that are made by the elderly while walking under different walking conditions.
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Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the (15)N:(14)N ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil. In both hot ecosystems and dry ecosystems, soil organic matter was more enriched in (15)N than in corresponding cold ecosystems or wet ecosystems. Below a MAT of 9.8°C, soil δ(15)N was invariant with MAT. At the global scale, soil organic C concentrations also declined with increasing MAT and decreasing MAP. After standardizing for variation among mineral soils in soil C and clay concentrations, soil δ(15)N showed no consistent trends across global climate and latitudinal gradients. Our analyses could place new constraints on interpretations of patterns of ecosystem N cycling and global budgets of gaseous N loss.
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We perform variational studies of the interaction-localization problem to describe the interaction-induced renormalizations of the effective (screened) random potential seen by quasiparticles. Here we present results of careful finite-size scaling studies for the conductance of disordered Hubbard chains at half-filling and zero temperature. While our results indicate that quasiparticle wave functions remain exponentially localized even in the presence of moderate to strong repulsive interactions, we show that interactions produce a strong decrease of the characteristic conductance scale g^{*} signaling the crossover to strong localization. This effect, which cannot be captured by a simple renormalization of the disorder strength, instead reflects a peculiar non-Gaussian form of the spatial correlations of the screened disordered potential, a hitherto neglected mechanism to dramatically reduce the impact of Anderson localization (interference) effects.
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The development of inhibitory antibodies against factor VIII (FVIII) (inhibitor) is the major complication in haemophilia A patients. The FVIII-binding antibodies development comprises a polyclonal immunoglobulin (Ig) G response. Recent studies showed strong correlation between the presence of neutralizing anti-FVIII antibodies (inhibitors) and IgG4 subclass. The aim of this study was to evaluate anti-FVIII IgG subclasses in haemophilia A patients with inhibitor both in a cross-sectional and in a longitudinal analysis. Inhibitors were determined by Nijmegen-Bethesda assay. Anti-FVIII IgG subclasses were performed by ELISA, and samples from 20 healthy individuals were used to validate the test. We studied 25 haemophilia A patients with inhibitor, previously treated exclusively with plasma-derived FVIII concentrates or bypassing agents. The IgG subclasses distributions were evaluated in two groups of patients classified according to inhibitor response. IgG1 and IgG4 antibodies were most prominent in haemophilia A patients with inhibitors when compared with IgG2 and IgG3. This study reports for the first time the behaviour of FVIII-binding IgG1 and IgG4 subclasses in a longitudinal analysis, in a clinical setting, of high-response inhibitor haemophilia A patients, showing the correlation of IgG4 and the inhibitor titres. In spite of being considered a non-pathologic antibody subclass with anti-inflammatory properties in other situations, IgG4 is correlated with the presence of high-titre inhibitor in the haemophilia setting. The comprehension of the IgG4 role in immune response may be crucial to establish the process for designing specific tolerance to FVIII.
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Trees from tropical montane cloud forest (TMCF) display very dynamic patterns of water use. They are capable of downwards water transport towards the soil during leaf-wetting events, likely a consequence of foliar water uptake (FWU), as well as high rates of night-time transpiration (Enight) during drier nights. These two processes might represent important sources of water losses and gains to the plant, but little is known about the environmental factors controlling these water fluxes. We evaluated how contrasting atmospheric and soil water conditions control diurnal, nocturnal and seasonal dynamics of sap flow in Drimys brasiliensis (Miers), a common Neotropical cloud forest species. We monitored the seasonal variation of soil water content, micrometeorological conditions and sap flow of D. brasiliensis trees in the field during wet and dry seasons. We also conducted a greenhouse experiment exposing D. brasiliensis saplings under contrasting soil water conditions to deuterium-labelled fog water. We found that during the night D. brasiliensis possesses heightened stomatal sensitivity to soil drought and vapour pressure deficit, which reduces night-time water loss. Leaf-wetting events had a strong suppressive effect on tree transpiration (E). Foliar water uptake increased in magnitude with drier soil and during longer leaf-wetting events. The difference between diurnal and nocturnal stomatal behaviour in D. brasiliensis could be attributed to an optimization of carbon gain when leaves are dry, as well as minimization of nocturnal water loss. The leaf-wetting events on the other hand seem important to D. brasiliensis water balance, especially during soil droughts, both by suppressing tree transpiration (E) and as a small additional water supply through FWU. Our results suggest that decreases in leaf-wetting events in TMCF might increase D. brasiliensis water loss and decrease its water gains, which could compromise its ecophysiological performance and survival during dry periods.
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Despite a strong increase in research on seamounts and oceanic islands ecology and biogeography, many basic aspects of their biodiversity are still unknown. In the southwestern Atlantic, the Vitória-Trindade Seamount Chain (VTC) extends ca. 1,200 km offshore the Brazilian continental shelf, from the Vitória seamount to the oceanic islands of Trindade and Martin Vaz. For a long time, most of the biological information available regarded its islands. Our study presents and analyzes an extensive database on the VTC fish biodiversity, built on data compiled from literature and recent scientific expeditions that assessed both shallow to mesophotic environments. A total of 273 species were recorded, 211 of which occur on seamounts and 173 at the islands. New records for seamounts or islands include 191 reef fish species and 64 depth range extensions. The structure of fish assemblages was similar between islands and seamounts, not differing in species geographic distribution, trophic composition, or spawning strategies. Main differences were related to endemism, higher at the islands, and to the number of endangered species, higher at the seamounts. Since unregulated fishing activities are common in the region, and mining activities are expected to drastically increase in the near future (carbonates on seamount summits and metals on slopes), this unique biodiversity needs urgent attention and management.
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Interactions between flowers and their visitors span the spectrum from mutualism to antagonism. The literature is rich in studies focusing on mutualism, but nectar robbery has mostly been investigated using phytocentric approaches focused on only a few plant species. To fill this gap, we studied the interactions between a nectar-robbing hermit hummingbird, Phaethornis ruber, and the array of flowers it visits. First, based on a literature review of the interactions involving P. ruber, we characterized the association of floral larceny to floral phenotype. We then experimentally examined the effects of nectar robbing on nectar standing crop and number of visits of the pollinators to the flowers of Canna paniculata. Finally, we asked whether the incorporation of illegitimate interactions into the analysis affects plant-hummingbird network structure. We identified 97 plant species visited by P. ruber and found that P. ruber engaged in floral larceny in almost 30 % of these species. Nectar robbery was especially common in flowers with longer corolla. In terms of the effect on C. paniculata, the depletion of nectar due to robbery by P. ruber was associated with decreased visitation rates of legitimate pollinators. At the community level, the inclusion of the illegitimate visits of P. ruber resulted in modifications of how modules within the network were organized, notably giving rise to a new module consisting of P. ruber and mostly robbed flowers. However, although illegitimate visits constituted approximately 9 % of all interactions in the network, changes in nestedness, modularity, and network-level specialization were minor. Our results indicate that although a flower robber may have a strong effect on the pollination of a particular plant species, the inclusion of its illegitimate interactions has limited capacity to change overall network structure.
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Focal cryoablation (FC), brachytherapy (B) and active surveillance (AS) were offered to patients diagnosed with very low-risk prostate cancer (VLRPC) in an equal access protocol. Comprehensive validated self-report questionnaires accessed patients' erectile (IIEF-5) and voiding (IPSS) functions, Beck scales measured anxiety (BAI), hopelessness (BHS) and depression (BDI), SF-36 reflected patients' quality of life added to the emotional thermometers including five visual analogue scales (distress, anxiety, depression, anger and need for help). Kruskal-Wallis or ANOVA tests and Spearman's correlations were obtained among groups and studied variables. Thirty patients were included, median follow-up 18 months (15-21). Those on AS (n = 11) were older, presented higher hopelessness (BHS) and lower general health perceptions (SF-36) scores than patients opting for FC (n = 10) and B (n = 9), P = 0.0014, P = 0.0268 and P = 0.0168 respectively. Patients on B had higher IPSS scores compared to those under FC and AC, P = 0.0223. For all 30 included patients, Spearman's correlation (rs ) was very strong between BHS and general health perceptions (rs = -0.800, P < 0.0001), and weak/moderate between age and BHS (rs = 0.405, P = 0.026) and age and general health perceptions (rs = -0.564, P = 0.001). The sample power was >60%. To be considered in patients' counselling and care, current study supports the hypothesis that even VLRPC when untreated undermines psychosocial domains.
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A retrospective cohort. To report the incidence rates of shoulder injuries diagnosed with magnetic resonance imaging (MRI) in tetraplegic athletes and sedentary tetraplegic individuals. To evaluate whether sport practice increases the risk of shoulder injuries in tetraplegic individuals. Campinas, Sao Paulo, Brazil. Ten tetraplegic athletes with traumatic spinal cord injury were selected among quad rugby athletes and had both the shoulders evaluated by MRI. They were compared with 10 sedentary tetraplegic individuals who were submitted to the same radiological protocol. All athletes were male with a mean age of 32.1 years (range 25-44 years, s.d.=6.44). Time since injury ranged from 6 to 17 years, with a mean value of 9.7 years and s.d. of 3.1 years. All sedentary individuals were male with a mean age of 35.9 years (range 22-47 years, s.d.=8.36). Statistical analysis showed a protective effect of sport in the development of shoulder injuries, with a weak correlation for infraspinatus and subscapularis tendinopathy (P=0.09 and P=0.08, respectively) and muscle atrophy (P=0.08). There was a strong correlation for acromioclavicular joint (ACJ) and labrum injuries (P=0.04), with sedentary individuals at a higher risk for these injuries. Tetraplegic athletes and sedentary individuals have a high incidence of supraspinatus tendinosis, bursitis and ACJ degeneration. Statistical analysis showed that there is a possible protective effect of sport in the development of shoulder injuries. Weak evidence was encountered for infraspinatus and subscapularis tendinopathy and muscle atrophy (P=0.09, P=0.08 and P=0.08, respectively). Strong evidence with P=0.04 suggests that sedentary tetraplegic individuals are at a greater risk for ACJ and labrum injuries.Spinal Cord advance online publication, 17 March 2015; doi:10.1038/sc.2014.248.
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G-quadruplexes are secondary structures present in DNA and RNA molecules, which are formed by stacking of G-quartets (i.e., interaction of four guanines (G-tracts) bounded by Hoogsteen hydrogen bonding). Human PAX9 intron 1 has a putative G-quadruplex-forming region located near exon 1, which is present in all known sequenced placental mammals. Using circular dichroism (CD) analysis and CD melting, we showed that these sequences are able to form highly stable quadruplex structures. Due to the proximity of the quadruplex structure to exon-intron boundary, we used a validated double-reporter splicing assay and qPCR to analyze its role on splicing efficiency. The human quadruplex was shown to have a key role on splicing efficiency of PAX9 intron 1, as a mutation that abolished quadruplex formation decreased dramatically the splicing efficiency of human PAX9 intron 1. The less stable, rat quadruplex had a less efficient splicing when compared to human sequences. Additionally, the treatment with 360A, a strong ligand that stabilizes quadruplex structures, further increased splicing efficiency of human PAX9 intron 1. Altogether, these results provide evidences that G-quadruplex structures are involved in splicing efficiency of PAX9 intron 1.