175 research outputs found

    Efficacy of a Laser Device for Hazing Canada Geese from Urban Areas of Northeast Ohio

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    Author Institution: Ohio Department of Natural Resources, Division of Wildlife, Crane Creek Wildlife Research Station ; US Department of Agriculture, APHIS, Wildlife ServicesComplaints about Canada geese in Ohio have increased nearly 400% in the past decade, with 732 recorded in 2001. Harassment techniques such as pyrotechnics and mylar flagging have been used to reduce goose conflicts but are frequently ineffective, and initial experiments indicated that laser harassment may disperse Canada geese. We evaluated whether lasers could cause geese to abandon urban sites, the duration of site abandonment, and dispersal distance of harassed geese. One hundred ninety geese were banded and collared in June 2001 at 6 sites in northeast Ohio. Radio transmitters were attached to 40 collars. We conducted nocturnal laser harassment of geese in four 5-day periods from July 2001 through January 2002 at 3 treatment sites. No harassment occurred at 3 control sites. One-day surveys of collared geese were conducted 2 weeks prior to the 5-day hazing period, during the hazing period, and 2 weeks post-hazing. Geese were located through radio telemetry using air- and ground-based receivers during all 3 time periods. Laser harassment caused geese to leave the site after a mean of 4.6 (SE = 0.8) minutes of treatment. Over the 5-day treatment period, the mean number of geese observed at night decreased from 92 to 14; however, we found no differences between numbers of geese observed 2 weeks prior to initial harassment and those observed post-harassment. Telemetry indicated that geese moved <2.0 km from all but one banding site. Laser harassment was more effective in reducing goose numbers at night rather than reducing numbers during the day. Site characteristics such as ambient lighting, human disturbance, and size of pond appeared to be the primary factors determining the laser’s effectiveness

    GAP-independent functions of DLC1 in metastasis

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    Metastases are responsible for most cancer-related deaths. One of the hallmarks of metastatic cells is increased motility and migration through extracellular matrixes. These processes rely on specific small GTPases, in particular those of the Rho family. Deleted in liver cancer-1 (DLC1) is a tumor suppressor that bears a RhoGAP activity. This protein is lost in most cancers, allowing malignant cells to proliferate and disseminate in a Rho-dependent manner. However, DLC1 is also a scaffold protein involved in alternative pathways leading to tumor and metastasis suppressor activities. Recently, substantial information has been gathered on these mechanisms and this review is aiming at describing the potential and known alternative GAP-independent mechanisms allowing DLC1 to impair migration, invasion, and metastasis formation

    The ubiK protein is an accessory factor necessary for bacterial Ubiquinone (UQ) biosynthesis and forms a complex with the UQ biogenesis factor UbiJ

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    Ubiquinone (UQ), also referred to as coenzyme Q, is a widespread lipophilic molecule in both prokaryotes and eukaryotes in which it primarily acts as an electron carrier. Eleven proteins are known to participate in UQ biosynthesis in Escherichia coli, and we recently demonstrated that UQ biosynthesis requires additional, nonenzymatic factors, some of which are still unknown. Here, we report on the identification of a bacterial gene, yqiC, which is required for efficient UQ biosynthesis, and which we have renamed ubiK. Using several methods, we demonstrated that the UbiK protein forms a complex with the C-terminal part of UbiJ, another UQ biogenesis factor we previously identified. We found that both proteins are likely to contribute to global UQ biosynthesis rather than to a specific biosynthetic step, because both ubiK and ubiJ mutants accumulated octaprenylphenol, an early intermediate of the UQ biosynthetic pathway. Interestingly, we found that both proteins are dispensable for UQ biosynthesis under anaerobiosis, even though they were expressed in the absence of oxygen. We also provide evidence that the UbiK-UbiJ complex interacts with palmitoleic acid, a major lipid in E. coli. Last, in Salmonella enterica, ubiK was required for proliferation in macrophages and virulence in mice. We conclude that although the role of the UbiK-UbiJ complex remains unknown, our results support the hypothesis that UbiK is an accessory factor of Ubi enzymes and facilitates UQ biosynthesis by acting as an assembly factor, a targeting factor, or both.Agence Nationale de la Recherche ANR-15-CE11-0001-02Centre National de la Recherche Scientifique PICS07279French State Program "Investissements d'Avenir" ANR-11-LABX-001

    "Come i secchi nel pozzo". Scienza ed etica negli scritti contro la vivisezione delle femministe britanniche (1870-1910)

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    Il saggio ripercorre le riflessioni teoriche delle femministe britanniche su scienza ed etica in relazione al dibattito sulla vivisezion

    Bayesian estimation of tobramycin exposure in cystic fibrosis

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    Fixed tobramycin (mg/kg) dosing is often inappropriate in patients with cystic fibrosis (CF), as pharmacokinetics are highly variable. The area under the concentration-time curve (AUC) is an exposure metric suited to monitoring in this population. Bayesian strategies to estimate AUC have been available for over 20 years but are not standard practice in the clinical setting. To assess their suitability for use in clinical practice, three AUC estimation methods using limited sampling were compared to measured true exposure by using intensive sampling tobramycin data. Adults prescribed once daily intravenous tobramycin had eight concentrations taken over 24 h. An estimate of true exposure within one dosing interval was calculated using the trapezoidal method and compared to three alternate estimates determined using (i) a two-sample log-linear regression (LLR) method (local hospital practice); (ii) a Bayesian estimate using one concentration (AUC(1)); and (iii) a Bayesian estimate using two concentrations (AUC(2)). Each method was evaluated against the true measured exposure by a Bland-Altman analysis. Twelve patients with a median (range) age and weight of 25 (18 to 36) years and 66.5 (51 to 76) kg, respectively, were recruited. There was good agreement between the true exposure and the three alternate estimates of AUC, with a mean AUC bias of < 10 mg/liter center dot h in each case, i.e., -8.2 (LLR), 3.8 (AUC(1)), and 1.0 (AUC(2)). Bayesian analysis-based and LLR estimation methods of tobramycin AUC are equivalent to true exposure estimation. All three methods may be suitable for use in the clinical setting; however, a one-sample Bayesian method may be most useful in ambulatory patients for which coordinating blood samples is difficult. Suitably powered, randomized clinical trials are required to assess patient outcomes

    Is it Alpha or Beta? Decomposing Hedge Fund Returns When Models are Misspecified

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    The decomposition of hedge fund returns is hampered by model misspecification. To address this issue, we develop a novel approach to compare models in a large population of funds. This comparison, which accounts for misspecification-driven estimation errors, sharpens the separation between alpha and beta. Our analysis reveals that: (i) prominent models are as misspecified as the CAPM, (ii) several factors—primarily time-series momentum, variance, carry—capture hedge fund strategies and lower performance, (iii) alpha and beta components correlate negatively and vary substantially across funds, consistent with equilibrium models featuring search costs, and (iv) fund valuation is sensitive to investor sophistication.Paper No. 20-8

    A study of frictional contact in dynamic fracture along bimaterial interfaces

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    We investigate numerically the dynamic in-plane propagation of a centered crack along bimaterial interfaces using a spectral formulation of the elastodynamic boundary integral equations. Particular attention is given to the effect of contact zones at the subsonic/intersonic transition. In a single set-up, we simulate and describe the different phenomenon observed experimentally (distinct natures of contact zones, unfavorable velocity range, asymmetric crack propagation). We show that different behaviors are observed as function of the crack propagation direction, i.e., with respect to the particle displacements of the compliant material. When the crack propagates in the same direction, the propagation velocities between cRc_\mathrm{R} c R and csc_\mathrm{s} c s are forbidden and the subsonic/intersonic transition occurs with the nucleation of a daughter crack in front of the main rupture. The intersonic stress field at the crack front is compressive due to the material mismatch and a contact zone appears behind the tip. In the opposite direction, a smooth subsonic/intersonic transition occurs although crack face closure (in normal direction) is observed for speeds between csc_\mathrm{s} c s and 2cs\sqrt{2}c_\mathrm{s} 2 c s . In this regime, a Rayleigh disturbance is generated at the crack surface causing a contact zone which detaches from the tip. Using a contact model governed by a regularized Coulomb law, we provide a quantitative evaluation of the influence of friction on the effective fracture toughness. Finally, we show the applicability of our analysis to the description of different bimaterial situations as well as the single-material set-up

    A Well-Controlled Experimental System to Study Interactions of Cytotoxic T Lymphocytes with Tumor Cells.

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    While T cell-based immunotherapies are steadily improving, there are still many patients who progress, despite T cell-infiltrated tumors. Emerging evidence suggests that T cells themselves may provoke immune escape of cancer cells. Here, we describe a well-controlled co-culture system for studying the dynamic T cell - cancer cell interplay, using human melanoma as a model. We explain starting material, controls, and culture parameters to establish reproducible and comparable cultures with highly heterogeneous tumor cells. Low passage melanoma cell lines and melanoma-specific CD8+ T cell clones generated from patient blood were cultured together for up to 3 days. Living melanoma cells were isolated from the co-culture system by fluorescence-activated cell sorting. We demonstrate that the characterization of isolated melanoma cells is feasible using flow cytometry for protein expression analysis as well as an Agilent whole human genome microarray and the NanoString technology for differential gene expression analysis. In addition, we identify five genes (ALG12, GUSB, RPLP0, KRBA2, and ADAT2) that are stably expressed in melanoma cells independent of the presence of T cells or the T cell-derived cytokines IFNγ and TNFα. These genes are essential for correct normalization of gene expression data by NanoString. Further to the characterization of melanoma cells after exposure to CTLs, this experimental system might be suitable to answer a series of questions, including how the affinity of CTLs for their target antigen influences the melanoma cell response and whether CTL-induced gene expression changes in melanoma cells are reversible. Taken together, our human T cell - melanoma cell culture system is well suited to characterize immune-related mechanisms in cancer cells

    Organic electrode coatings for next-generation neural interfaces

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    Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes
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