Age, Sex and Family Composition of Montezuma Quail (Cyrtonyx montezumae) Coveys in Arizona, New Mexico, and Texas

The Montezuma quail (Cyrtonyx montezumae) is a popular game bird in Arizona and New Mexico, USA, but hunting seasons remain closed in Texas, USA. Estimates of age structure parameters and sex ratios in game birds are essential information for predicting population trajectories and developing sustainable harvest and conservation strategies. Montezuma quail form coveys during the winter as a behavioral strategy for improved survival. In this regard, we harvested 1–4 individuals from 112 Montezuma quail coveys in Arizona, New Mexico, and West Texas from 2009 through 2020 to estimate sex and age composition (juvenile vs. adults) of coveys. We also estimated size for all coveys from which we harvested birds. Mean covey size (± standard error) was 9.7 ± 0.7 individuals (range = 6–12), 9.1 ± 0.5 (range = 2–20), and 5.7 ± 0.7 (range = 2–12) for Arizona, New Mexico, and Texas, respectively although covey size decreased through the winter. The proportion of females among harvested birds was 0.33 ± 0.11, 0.40 ± 0.04, and 0.36 ± 0.33 for Arizona, New Mexico, and Texas, respectively. The proportion of juveniles among harvested birds was 0.83 ± 0.09, 0.71 ± 0.04, and 0.52 ± 0.10 for Arizona, New Mexico, and Texas, respectively. Coveys seem to contain more than one family group (paired birds with current progeny). We estimated that at least 6.2 ± 3.0% and 15.4 ± 10.0% of coveys were mixed families for New Mexico and Texas, respectively, as we harvested more than 2 adult males from the same covey. We did not collect same-sex adults from the same covey in Arizona. Our estimates set apart West Texas in lower average covey size and proportion of juveniles from Arizona and New Mexico at the northern edge of the species’ distribution and may reflect a different population dynamic in the region. However, our estimates must be taken with caution as behavioral response differences between sexes and age categories may differ and may not accurately reflect the actual sex, age, and family composition of Montezuma quail coveys. In addition, results may be confounded by variability in environmental factors over our extended sampling period

On the accuracy of the Perturbative Approach for Strong Lensing: Local Distortion for Pseudo-Elliptical Models

The Perturbative Approach (PA) introduced by \citet{alard07} provides analytic solutions for gravitational arcs by solving the lens equation linearized around the Einstein ring solution. This is a powerful method for lens inversion and simulations in that it can be used, in principle, for generic lens models. In this paper we aim to quantify the domain of validity of this method for three quantities derived from the linearized mapping: caustics, critical curves, and the deformation cross section (i.e. the arc cross section in the infinitesimal circular source approximation). We consider lens models with elliptical potentials, in particular the Singular Isothermal Elliptic Potential and Pseudo-Elliptical Navarro--Frenk--White models. We show that the PA is exact for this first model. For the second, we obtain constraints on the model parameter space (given by the potential ellipticity parameter $\varepsilon$ and characteristic convergence $\kappa_s$) such that the PA is accurate for the aforementioned quantities. In this process we obtain analytic expressions for several lensing functions, which are valid for the PA in general. The determination of this domain of validity could have significant implications for the use of the PA, but it still needs to be probed with extended sources.Comment: Accepted for publication in MNRA

The Bak-Sneppen Model on Scale-Free Networks

We investigate by numerical simulations and analytical calculations the Bak-Sneppen model for biological evolution in scale-free networks. By using large scale numerical simulations, we study the avalanche size distribution and the activity time behavior at nodes with different connectivities. We argue the absence of a critical barrier and its associated critical behavior for infinite size systems. These findings are supported by a single site mean-field analytic treatment of the model.Comment: 5 pages and 3 eps figures. Final version appeared in Europhys. Let

Luminescent hyperbolic metasurfaces.

When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells

Can counseling prevent or treat postpartum depression?

In most cases, counseling does not prevent postpartum depression (PPD), though it can treat the disorder. Overall, psychosocial interventions don't offer a significantly greater benefit than standard care in preventing PPD--although studies do suggest a preventive benefit when the intervention is administered postnatally, in the home, and targeted toward individual at-risk women (strength of recommendation [SOR]: A, meta-analysis of 15 randomized, controlled trials [RCTs] and 1 subsequent RCT)