934 research outputs found
Trapping \u3cem\u3ePhyllophaga\u3c/em\u3e spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada Using Sex Attractants
The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester
The Stochastic Dynamics of Tethered Microcantilevers in a Viscous Fluid
We explore and quantify the coupled dynamics of a pair of micron scale cantilevers immersed in a viscous fluid that are also directly tethered to one another at their tips by a spring force. The spring force, for example, could represent the molecular stiffness or elasticity of a biomolecule or material tethered between the cantilevers. We use deterministic numerical simulations with the fluctuation-dissipation theorem to compute the stochastic dynamics of the cantilever pair for the conditions of experiment when driven only by Brownian motion. We validate our approach by comparing directly with experimental measurements in the absence of the tether which shows excellent agreement. Using numerical simulations, we quantify the correlated dynamics of the cantilever pair over a range of tether stiffness. Our results quantify the sensitivity of the auto- and cross-correlations of equilibrium fluctuations in cantilever displacement to the stiffness of the tether. We show that the tether affects the magnitude of the correlations which can be used in a measurement to probe the properties of an attached tethering substance. For the configurations of current interest using micron scale cantilevers in water, we show that the magnitude of the fluid coupling between the cantilevers is sufficiently small such that the influence of the tether can be significant. Our results show that the cross-correlation is more sensitive to tether stiffness than the auto-correlation indicating that a two-cantilever measurement has improved sensitivity when compared with a measurement using a single cantilever
Angiopoietin-like protein 2 regulates endothelial colony forming cell vasculogenesis
Angiopoietin-like 2 (ANGPTL2) has been reported to induce sprouting angiogenesis; however, its role in vasculogenesis, the de novo lumenization of endothelial cells (EC), remains unexplored. We sought to investigate the potential role of ANGPTL2 in regulating human cord blood derived endothelial colony forming cell (ECFC) vasculogenesis through siRNA mediated inhibition of ANGPTL2 gene expression. We found that ECFCs in which ANGPTL2 was diminished displayed a threefold decrease in in vitro lumenal area whereas addition of exogenous ANGPTL2 protein domains to ECFCs lead to increased lumen formation within a 3 dimensional (3D) collagen assay of vasculogenesis. ECFC migration was attenuated by 36 % via ANGPTL2 knockdown (KD) although proliferation and apoptosis were not affected. We subsequently found that c-Jun NH2-terminal kinase (JNK), but not ERK1/2, phosphorylation was decreased upon ANGPTL2 KD, and expression of membrane type 1 matrix metalloproteinase (MT1-MMP), known to be regulated by JNK and a critical regulator of EC migration and 3D lumen formation, was decreased in lumenized structures in vitro derived from ANGPTL2 silenced ECFCs. Treatment of ECFCs in 3D collagen matrices with either a JNK inhibitor or exogenous rhTIMP-3 (an inhibitor of MT1-MMP activity) resulted in a similar phenotype of decreased vascular lumen formation as observed with ANGPTL2 KD, whereas stimulation of JNK activity increased vasculogenesis. Based on gene silencing, pharmacologic, cellular, and biochemical approaches, we conclude that ANGPTL2 positively regulates ECFC vascular lumen formation likely through its effects on migration and in part by activating JNK and increasing MT1-MMP expression
High-Efficiency K-Band Space Traveling-Wave Tube Amplifier for Near-Earth High Data Rate Communications
The RF performance of a new K-Band helix conduction cooled traveling-wave tube amplifier (TWTA) is presented in this paper. A total of three such units were manufactured, tested and delivered. The first unit is currently flying onboard NASA s Lunar Reconnaissance Orbiter (LRO) spacecraft and has flawlessly completed over 2000 orbits around the Moon. The second unit is a proto-flight model. The third unit will fly onboard NASA s International Space Station (ISS) as a very compact and lightweight transmitter package for the Communications, Navigation and Networking Reconfigurable Testbed (CoNNeCT), which is scheduled for launch in 2011. These TWTAs were characterized over the frequencies 25.5 to 25.8 GHz. The saturated RF output power is >40 W and the saturated RF gain is >46 dB. The saturated AM-to- PM conversion is 3.5 /dB and the small signal gain ripple is 0.46 dB peak-to-peak. The overall efficiency of the TWTA, including that of the electronic power conditioner (EPC) is as high as 45 percent
Sex Pheromone Responses of the Oriental Beetle (Coleoptera: Scarabaeidae)
The synthetic female sex pheromone of the oriental beetle, Anomala orientalis Waterhouse, was evaluated in the field and in a sustained-flight tunnel. In a 2-wk period, > 150,000 beetles were captured on three golf course fairways in Connecticut. Contrary to earlier reports that these beetles are most active during the warm, sunny portions of the day, we observed that peak activity occurs around sunset. Ten micrograms of either (Z)-7-tetradecen-2-one or an 89/11 (Z/E) blend on a rubber septum was found to be the minimum concentration with which no significant decrease in catch was observed in the field. There was no discrimination between Z and the blend at 1 μg and higher concentrations, but the E-isomer alone trapped significantly fewer beetles than either Z alone or the blend. These results are consistent with the flight tunnel data. The effects of temperature and light intensity on the mating behavior of A. orientalis also are discusse
The subduction experiment : cruise report R/V Knorr : cruise number 138 leg XV : subduction 3 mooring recovery cruise, 13-30 June 1993
Subduction is the mechanism by which water masses formed in the mixed layer and near the surface of the ocean find their
way into the upper thermocline. The subduction process and its underlying mechanisms were studied though a combination of
Eulerian and Langrangian measurements of velocity, measurements of tracer distributions and hydrographic properties and modeling.
An array of five surface moorings carrying meteorological and oceanographic instrumentation were deployed for a period of
two years beginning in June 1991 as part of an Office of Naval Research (ONR) funded Subduction experiment. Three eight month
deployments were planned. The moorings were deployed at 18°N 34°W, 18°N 22°W, 25.5°N 29°W, 33°N 22°W and 33°N 34°W.
A Vector Averaging Wind Recorder (VAWR) and an Improved Meteorological Recorder (IMET) collected wind speed and
wind direction, sea surface temperature, air temperature, short wave radiation, barometric pressure and relative humidity. The IMET
also measured precipitation. The moorings were heavily instrumented below the surface with Vector Measuring Current Meters
(VMCM) and single point temperature recorders.
Expendable bathythermograph (XBT) data were collected and meteorological observations were made while transmitting
between mooring locations.
This report describes the work that took place during R/V Knorr cruise number 138 leg XV which was the fourth scheduled
Subduction mooring cruise. During this cruise the moorings previously deployed for a third and final eight month period were
recovered. This report includes a description of the moorings and instrumentation that were recovered, has information about the
underway measurements (XBT and meteorological observations) that were made including plots of the data, and presents a chronology
of the cruise events.Funding provided by the Office of Naval Research under
Contract No. N00014-90-J-1490
Amplification of Fluctuations in Unstable Systems with Disorder
We study the early-stage kinetics of thermodynamically unstable systems with
quenched disorder. We show analytically that the growth of initial fluctuations
is amplified by the presence of disorder. This is confirmed by numerical
simulations of morphological phase separation (MPS) in thin liquid films and
spinodal decomposition (SD) in binary mixtures. We also discuss the
experimental implications of our results.Comment: 15 pages, 4 figure
Reduction in ventral striatal activity when anticipating a reward in depression and schizophrenia: a replicated cross-diagnostic finding.
In the research domain framework (RDoC), dysfunctional reward expectation has been proposed to be a cross-diagnostic domain in psychiatry, which may contribute to symptoms common to various neuropsychiatric conditions, such as anhedonia or apathy/avolition. We used a modified version of the Monetary Incentive Delay (MID) paradigm to obtain functional MRI images from 22 patients with schizophrenia, 24 with depression and 21 controls. Anhedonia and other symptoms of depression, and overall positive and negative symptomatology were also measured. We hypothesized that the two clinical groups would have a reduced activity in the ventral striatum when anticipating reward (compared to anticipation of a neutral outcome) and that striatal activation would correlate with clinical measures of motivational problems and anhedonia. Results were consistent with the first hypothesis: two clusters in both the left and right ventral striatum were found to differ between the groups in reward anticipation. Post-hoc analysis showed that this was due to higher activation in the controls compared to the schizophrenia and the depression groups in the right ventral striatum, with activation differences between depression and controls also seen in the left ventral striatum. No differences were found between the two patient groups, and there were no areas of abnormal cortical activation in either group that survived correction for multiple comparisons. Reduced ventral striatal activity was related to greater anhedonia and overall depressive symptoms in the schizophrenia group, but not in the participants with depression. Findings are discussed in relation to previous literature but overall are supporting evidence of reward system dysfunction across the neuropsychiatric continuum, even if the specific clinical relevance is still not fully understood. We also discuss how the RDoC approach may help to solve some of the replication problems in psychiatric fMRI research.Supported by the Wellcome Trust Institutional Strategic Support Fund [097814/Z/11], a MRC Clinician Scientist [G0701911], a Brain and Behavior Research Foundation Young Investigator, and an Isaac Newton Trust award to Dr Murray; an award to Dr Segarra from the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia and the European Union; by the University of Cambridge Behavioural and Clinical Neuroscience Institute, funded by a joint award from the Medical Research Council [G1000183]and Wellcome Trust [093875/Z/10/Z]; by awards from the Wellcome Trust [095692] and the Bernard Wolfe Health Neuroscience Fund to Dr. Fletcher, and by the Cambridge NIHR Biomedical Research Centre.This is the final version of the article. It first appeared from Frontiers via http://dx.doi.org/10.3389/fpsyg.2015.0128
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