205 research outputs found

    Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

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    We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio

    Tick burden on European roe deer (Capreolus capreolus)

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    In our study we assessed the tick burden on roe deer (Capreolus capreolus L.) in relation to age, physical condition, sex, deer density and season. The main objective was to find predictive parameters for tick burden. In September 2007, May, July, and September 2008, and in May and July 2009 we collected ticks on 142 culled roe deer from nine forest departments in Southern Hesse, Germany. To correlate tick burden and deer density we estimated deer density using line transect sampling that accounts for different detectability in March 2008 and 2009, respectively. We collected more than 8,600 ticks from roe deer heads and necks, 92.6% of which were Ixodes spp., 7.4% Dermacentor spp. Among Ixodes, 3.3% were larvae, 50.5% nymphs, 34.8% females and 11.4% males, with significant seasonal deviation. Total tick infestation was high, with considerable individual variation (from 0 to 270 ticks/deer). Adult tick burden was positively correlated with roe deer body indices (body mass, age, hind foot length). Significantly more nymphs were found on deer from forest departments with high roe deer density indices, indicating a positive correlation with deer abundance. Overall, tick burden was highly variable. Seasonality and large scale spatial characteristics appeared to be the most important factors affecting tick burden on roe deer

    Microbial Symbionts in Insects Influence Down-Regulation of Defense Genes in Maize

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    Diabrotica virgifera virgifera larvae are root-feeding insects and significant pests to maize in North America and Europe. Little is known regarding how plants respond to insect attack of roots, thus complicating the selection for plant defense targets. Diabrotica virgifera virgifera is the most successful species in its genus and is the only Diabrotica beetle harboring an almost species-wide Wolbachia infection. Diabrotica virgifera virgifera are infected with Wolbachia and the typical gut flora found in soil-living, phytophagous insects. Diabrotica virgifera virgifera larvae cannot be reared aseptically and thus, it is not possible to observe the response of maize to effects of insect gut flora or other transient microbes. Because Wolbachia are heritable, it is possible to investigate whether Wolbachia infection affects the regulation of maize defenses. To answer if the success of Diabrotica virgifera virgifera is the result of microbial infection, Diabrotica virgifera virgifera were treated with antibiotics to eliminate Wolbachia and a microarray experiment was performed. Direct comparisons made between the response of maize root tissue to the feeding of antibiotic treated and untreated Diabrotica virgifera virgifera show down-regulation of plant defenses in the untreated insects compared to the antibiotic treated and control treatments. Results were confirmed via QRT-PCR. Biological and behavioral assays indicate that microbes have integrated into Diabrotica virgifera virgifera physiology without inducing negative effects and that antibiotic treatment did not affect the behavior or biology of the insect. The expression data and suggest that the pressure of microbes, which are most likely Wolbachia, mediate the down-regulation of many maize defenses via their insect hosts. This is the first report of a potential link between a microbial symbiont of an insect and a silencing effect in the insect host plant. This is also the first expression profile for a plant attacked by a root-feeding insect

    As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli

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    Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits

    Multiplicity of cerebrospinal fluid functions: New challenges in health and disease

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    This review integrates eight aspects of cerebrospinal fluid (CSF) circulatory dynamics: formation rate, pressure, flow, volume, turnover rate, composition, recycling and reabsorption. Novel ways to modulate CSF formation emanate from recent analyses of choroid plexus transcription factors (E2F5), ion transporters (NaHCO3 cotransport), transport enzymes (isoforms of carbonic anhydrase), aquaporin 1 regulation, and plasticity of receptors for fluid-regulating neuropeptides. A greater appreciation of CSF pressure (CSFP) is being generated by fresh insights on peptidergic regulatory servomechanisms, the role of dysfunctional ependyma and circumventricular organs in causing congenital hydrocephalus, and the clinical use of algorithms to delineate CSFP waveforms for diagnostic and prognostic utility. Increasing attention focuses on CSF flow: how it impacts cerebral metabolism and hemodynamics, neural stem cell progression in the subventricular zone, and catabolite/peptide clearance from the CNS. The pathophysiological significance of changes in CSF volume is assessed from the respective viewpoints of hemodynamics (choroid plexus blood flow and pulsatility), hydrodynamics (choroidal hypo- and hypersecretion) and neuroendocrine factors (i.e., coordinated regulation by atrial natriuretic peptide, arginine vasopressin and basic fibroblast growth factor). In aging, normal pressure hydrocephalus and Alzheimer's disease, the expanding CSF space reduces the CSF turnover rate, thus compromising the CSF sink action to clear harmful metabolites (e.g., amyloid) from the CNS. Dwindling CSF dynamics greatly harms the interstitial environment of neurons. Accordingly the altered CSF composition in neurodegenerative diseases and senescence, because of adverse effects on neural processes and cognition, needs more effective clinical management. CSF recycling between subarachnoid space, brain and ventricles promotes interstitial fluid (ISF) convection with both trophic and excretory benefits. Finally, CSF reabsorption via multiple pathways (olfactory and spinal arachnoidal bulk flow) is likely complemented by fluid clearance across capillary walls (aquaporin 4) and arachnoid villi when CSFP and fluid retention are markedly elevated. A model is presented that links CSF and ISF homeostasis to coordinated fluxes of water and solutes at both the blood-CSF and blood-brain transport interfaces

    Observation of a Charmed Baryon Decaying to D0p at a Mass Near 2.94 GeV/c2

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    A search for charmed baryons decaying to D 0 p reveals two states: the Λ c ( 2880 ) + baryon and a previously unobserved state at a mass of [ 2939.8 ± 1.3 ( stat ) ± 1.0 ( syst ) ]     MeV / c 2 and with an intrinsic width of [ 17.5 ± 5.2 ( stat ) ± 5.9 ( syst ) ]     MeV . Consistent and significant signals are observed for the K − π + and K − π + π − π + decay modes of the D 0 in 287     fb − 1 annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D + p spectrum of doubly charged partners. The mass and intrinsic width of the Λ c ( 2880 ) + baryon and relative yield of the two baryons are also measured

    An ex vivo human model system to evaluate specificity of replicating and non-replicating gene therapy agents

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    Background Inefficiency, aspecificity and toxicity of gene transfer vectors hamper gene therapy from showing its full potential. On this basis significant research currently focuses on developing vectors with improved infection and/or expression profiles. Screening assays with validity to the clinical context to determine improved characteristics of such agents are not readily available since this requires a close relationship to the human situation. We present a clinically relevant tissue slice technology to preclinically test improved vector characteristics. Methods Slices were prepared from rat, mouse and human liver samples and from tumor tissue. Specificity of gene expression and replication was determined by infecting target and non-target tissue slices with transcriptionally retargeted adenoviruses and oncolytic viruses. Results Using rat liver slices, we demonstrate efficient knob-mediated adenoviral infectivity. A favorable tumor-on/liver-off profile, resembling in vitro and mouse in vivo data, was shown for a tumor-specific transcriptionally retargeted adenovirus by infecting slices prepared from tumor or liver tissue. Similar liver-off data were found for mouse, rat and human samples (over 3-log lower activity of the tumor-specific promoter compared to cytomegalovirus (CMV)). More importantly, we show that this technology when applied to human livers is a powerful tool to determine aspecific replication of oncolytic viruses in liver tissue. A 2- to 6-log reduction in viral replication was observed for a tumor-specific oncolytic virus compared to the wild-type adenovirus. Conclusions The precision-cut tissue slice technology is a powerful method to test specificity and efficiency of gene transfer as well as of viral replication using human tissue. Copyright (c) 2005 John Wiley & Sons, Ltd
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