286 research outputs found
Encountering competitors reduces clutch size and increases offspring size in a parasitoid with female–female fighting
Understanding the size of clutches produced by only one parent may require a game-theoretic approach: clutch size may affect offspring fitness in terms of future competitive ability. If larger clutches generate smaller offspring and larger adults are more successful in acquiring and retaining resources, clutch size optima should be reduced when the probability of future competitive encounters is higher. We test this using Goniozus nephantidis, a gregarious parasitoid wasp in which the assumption of size-dependent resource acquisition is met via female–female contests for hosts. As predicted, smaller clutches are produced by mothers experiencing competition, due to fewer eggs being matured and to a reduced proportion of matured eggs being laid. As assumed, smaller clutches generate fewer but larger offspring. We believe this is the first direct evidence for pre-ovipositional and game-theoretic clutch size adjustment in response to an intergenerational fitness effect when clutches are produced by a single individual
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Neutron transport benchmarks for binary stochastic multiplying media : planar geometry, two energy groups
Benchmark calculations are performed for neutron transport in a two material
(binary) stochastic multiplying medium. Spatial, angular, and energy dependence
are included. The problem considered is based on a fuel assembly of a common
pressurized water nuclear reactor. The mean chord length through the assembly is
determined and used as the planar geometry system length. According to assumed
or calculated material distributions, this system length is populated with alternating
fuel and moderator segments of random size. Neutron flux distributions are
numerically computed using a discretized form of the Boltzmann transport equation
employing diffusion synthetic acceleration. Average quantities (group fluxes
and k-eigenvalue) and variances are calculated from an ensemble of realizations
of the mixing statistics. The effects of varying two parameters in the fuel, two
different boundary conditions, and three different sets of mixing statistics are assessed.
A probability distribution function (PDF) of the k-eigenvalue is generated
and compared with previous research. Atomic mix solutions are compared with
these benchmark ensemble average flux and k-eigenvalue solutions.
Mixing statistics with large standard deviations give the most widely varying
ensemble solutions of the flux and k-eigenvalue. The shape of the k-eigenvalue PDF
qualitatively agrees with previous work. Its overall shape is independent of variations
in fuel cross-sections for the problems considered, but its width is impacted
by these variations. Statistical distributions with smaller standard deviations alter
the shape of this PDF toward a normal distribution. The atomic mix approximation
yields large over-predictions of the ensemble average k-eigenvalue and under-predictions
of the flux. Qualitatively correct flux shapes are obtained, however.
These benchmark calculations indicate that a model which includes higher statistical
moments of the mixing statistics is needed for accurate predictions of binary
stochastic media k-eigenvalue problems. This is consistent with previous findings
Heavy Neutrino searches through Double-Bang Events at Super-Kamiokande, DUNE, and Hyper-Kamiokande
A variety of new physics scenarios allow for neutrinos to up-scatter into a
heavy neutral lepton state. For a range of couplings and neutrino energies, the
heavy neutrino may travel some distance before decaying to visible final
states. When both the up-scattering and decay occur within the detector volume,
these "double bang" events produce distinctive phenomenology with very low
background. In this work, we first consider the current sensitivity at
Super-Kamiokande via the atmospheric neutrino flux, and find current data may
already provide new constraints. We then examine projected future sensitivity
at DUNE and Hyper-Kamiokande, including both atmospheric and beam flux
contributions to double-bang signals.Comment: 17 pages, 6 figures. v2: minor changes, references added and typos
fixed. Matches version accepted for publication in JHE
Multiple Mechanisms Regulate NuMA Dynamics at Spindle Poles
The large coiled-coil protein NuMA plays an essential role in organizing microtubule minus ends at spindle poles in vertebrate cells. Here, we use both in vivo and in vitro methods to examine NuMA dynamics at mitotic spindle poles. Using fluorescence recovery after photobleaching, we show that an exogenously expressed green-fluorescent-protein/NuMA fusion undergoes continuous exchange between soluble and spindle-associated pools in living cells. These dynamics require cellular energy and display an average half-time for fluorescence recovery of approximately 3 minutes. To explore how NuMA dynamics at spindle poles is regulated, we exploited the association of NuMA with microtubule asters formed in mammalian mitotic extracts. Using a monoclonal antibody specific for human NuMA, we followed the fate of human NuMA associated with microtubule asters upon dilution with a hamster mitotic extract. Consistent with in vivo data, this assay shows that NuMA can be displaced from the core of pre-assembled asters into the soluble pool. The half-time of NuMA displacement from asters under these conditions is approximately 5 minutes. Using this assay, we show that protein kinase activity and the NuMA-binding protein LGN regulate the dynamic exchange of NuMA on microtubule asters. Thus, the dynamic properties of NuMA are regulated by multiple mechanisms including protein phosphorylation and binding to the LGN protein, and the rate of exchange between soluble and microtubule-associated pools suggests that NuMA associates with an insoluble matrix at spindle poles
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Everolimus Exposure as a Predictor of Toxicity in Renal Cell Cancer Patients in the Adjuvant Setting: Results of a Pharmacokinetic Analysis for SWOG S0931 (EVEREST), a Phase III Study (NCT01120249).
BackgroundS0931 is assessing recurrence-free survival in renal cell carcinoma (RCC) patients randomized to receive everolimus (EVE) versus placebo for one year following nephrectomy. Due to a higher than expected dropout rate, we assessed EVE trough levels in the adjuvant setting to evaluate the relationship between EVE exposure and probability of toxicity.MethodsPatients received 10 mg daily EVE for nine 6-week cycles. Pre-dose whole blood samples were collected pre-cycle 2 and pre-cycle 3 and analyzed for EVE. Patients with pre-cycle 2 and/or pre-cycle 3 EVE results were used in the analysis. Patients were segregated into quartiles (Q) based on EVE levels and logistic regression was used to model the most common adverse event outcomes using EVE trough as a predictor. Hazard and odds ratios were adjusted for age, BMI and performance status.ResultsA total of 467 patients were included in this analysis. Quartiles normalized to an EVE dose of 10 mg/day were < 9.0, 9.0-12.9, 12.9-22.8, and > 22.8 ng/mL, respectively. EVE trough levels increased with increasing age (p < 0.001). Furthermore, EVE trough levels were higher in men than women (19.4 versus 15.4 ng/mL, p = 0.01). Risk of grade 2 + triglycerides was increased in Q2 and Q3 vs Q1 (OR = 2.08; p = 0.02 and OR = 2.63; p = 0.002). Risk of grade 2 + rash was increased in Q2 and Q4 vs Q1 (OR = 2.99; p = 0.01 and OR = 2.90; p = 0.02). There was also an increased risk of any grade 3 + tox in Q2 vs Q1 (OR = 1.71; p = 0.05).ConclusionsWe identified significant gender and age-related differences in EVE trough levels in patients receiving adjuvant treatment for RCC. Furthermore, our analysis identified significant associations between EVE exposure and probability of toxicity
Practitioners' use of motivational interviewing in sport: A qualitative enquiry
This study explored the use of motivational interviewing (MI) in sport contexts by experts in that approach. Specifically, the purpose was to understand which aspects of the MI approach are deemed valuable for working in sport and to begin to understand how these aspects are best applied. Nine practitioners participated in semistructured interviews, and thematic analysis identified themes related to core and subcomponents of MI (e.g., relational spirit, technical microskills, applied tools, and the MI communication styles continuum). Additional themes relate to integrating MI with other interventions, the challenges of working with athletes (e.g., mandated attendance, ambivalence about change), and unique aspects of working in sport contexts (e.g., frequency, duration, and location of contact points). The participants also outlined essential ingredients for an MI training curriculum for practitioners in sport. This counseling approach appears to have valuable relational and technical components to facilitate the building of the therapeutic alliance, enhance athlete readiness for change, and support delivery of action-oriented interventions in applied sport psychology
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