Policing and Middle School: An Evaluation of a Statewide School Resource Officer Policy

This study investigates the effectiveness of North Carolina Senate Bill 402, Section 8.36 – Grants for School Resource Officers in Elementary and Middle Schools, which provides matching state funds to districts for use in middle and elementary schools. Using generalized difference-in-difference and negative binomial hurdle regression designs, seven years of data—inclusive of 110 districts and 471 middle schools—were analyzed to assess the effectiveness of the state-funded SRO program. Results show that offering matched SRO funds to increase policing and training was not associated with reductions in reported acts (infractions) per school year, a key measure of school safety. Racial enrollment percentages, such as higher enrollments of Black and Hispanic students, were generally not associated with increased disciplinary acts. However, total enrollment was associated with increases in reported acts and increased grade level proficiency was associated with reductions in reported acts. Findings also show that public policy activity generally increases after school shootings occur. However, a multi-pronged approach to school safety, beyond preventing mass acts of violence through increased policing, is recommended. Specifically, policies that focus on a broad range of issues, including those that improve academic achievement and address larger societal challenges have potential to enhance school safety

The present status of personnel work in a selected group of American colleges and universities

Thesis (M.A.)--Boston Universit

Sex-change rules, stock dynamics, and the performance of spawning-per-recruit measures in protogynous stocks

Predicting and under-standing the dynamics of a population requires knowledge of vital rates such as survival, growth, and reproduction. However, these variables are influenced by individual behavior, and when managing exploited populations, it is now generally realized that knowledge of a species’ behavior and life history strategies is required. However, predicting and understanding a response to novel conditions—such as increased fishing-induced mortality, changes in environmental conditions, or specific management strategies—also require knowing the endogenous or exogenous cues that induce phenotypic changes and knowing whether these behaviors and life history patterns are plastic. Although a wide variety of patterns of sex change have been observed in the wild, it is not known how the specific sex-change rule and cues that induce sex change affect stock dynamics. Using an individual based model, we examined the effect of the sex-change rule on the predicted stock dynamics, the effect of mating group size, and the performance of traditional spawning-per-recruit (SPR) measures in a protogynous stock. We considered four different patterns of sex change in which the probability of sex change is determined by 1) the absolute size of the individual, 2) the relative length of individuals at the mating site, 3) the frequency of smaller individuals at the mating site, and 4) expected reproductive success. All four pat-terns of sex change have distinct stock dynamics. Although each sex-change rule leads to the prediction that the stock will be sensitive to the size-selective fishing pattern and may crash if too many reproductive size classes are fished, the performance of traditional spawning-per-recruit measures, the fishing pattern that leads to the greatest yield, and the effect of mating group size all differ distinctly for the four sex-change rules. These results indicate that the management of individual species requires knowledge of whether sex change occurs, as well as an understanding of the endogenous or exogenous cues that induce sex change

Addressable refraction and curved soliton waveguides using electric interfaces

A great deal of interest over the years has been directed to the optical space solitons for the possibility of realizing 3D waveguides with very low propagation losses. A great limitation in their use for writing complex circuits is represented by the impossibility of making curved structures. In the past, solitons in nematic liquid crystals, called nematicons, were reflected on electrical interfaces, and recently on photorefractive spatial solitons as well. In the present work we investigate refraction and total reflection of spatial solitons with saturable electro-optic nonlinearity, such as the photorefractive ones, on an electric wall acting as a reflector. Using a custom FDTD code, the propagation of a self-confined beam was analyzed as a function of the applied electric bias. The electrical reflector has been simulated by applying different biases in two adjacent volumes. We have observed both smaller and larger angles of refraction, up to the critical π/2-refraction condition and then total reflection. The radii of curvature of the associated guides can be varied from centimeters down to hundreds of microns. The straight guides showed losses down to 0.07 dB/cm as previously observed, while the losses associated with single curves were estimated down to 0.2 dB

Energy-Efficient Downlink Power Control in mmWave Cell-Free and User-Centric Massive MIMO

This paper considers cell-free and user-centric approaches for coverage improvement in wireless cellular systems operating at millimeter wave frequencies, and proposes downlink power control algorithms aimed at maximizing the global energy efficiency. To tackle the non-convexity of the problems, an interaction between sequential and alternating optimization is considered. The use of hybrid analog/digital beamformers is also taken into account. The numerical results show the benefits obtained from the power control algorithm, as well as that the user-centric approach generally outperforms the cell-free one.Comment: 4 pages; to be presented at the IEEE 5G Worls Forum Conference, Santa Clara, July 2018. arXiv admin note: text overlap with arXiv:1710.0781

Predation risk reduces a female preference for heterospecific males in the green swordtail

The presence of a predator can result in the alteration, loss or reversal of a mating preference. Under predation risk, females often change their initial preference for conspicuous males, favouring less flashy males to reduce the risk of being detected by predators. Previous studies on predator-induced plasticity in mate preferences have given females a choice between more and less conspicuous conspecific males. However, in species that naturally hybridize, it is also possible that females might choose an inconspicuous heterospecific male over a conspicuous conspecific male under predation risk. Our study addresses this question using the green swordtail (Xiphophorus helleri) and the southern platyfish (Xiphophorus maculatus), which are sympatric in the wild. We hypothesized that X. helleri females would prefer the sworded conspecific males in the absence of a predator but favour the less conspicuous, swordless, heterospecific males in the presence of a predator. Contrary to our expectation, females associated more with the heterospecific male than the conspecific male in the control (no predator) treatment, and they were non-choosy in the predator treatment. This might reflect that females were attracted to the novel male phenotype when there was no risk of predation but became more neophobic after predator exposure. Regardless of the underlying mechanism, our results suggest that predation pressure may affect female preferences for conspecific versus heterospecific males. We also found striking within-population, between-individual variation in behavioural plasticity: females differed in the strength and direction of their preferences, as well as in the extent to which they altered their preferences in response to changes in perceived predation risk. Such variation in female preferences for heterospecific males could potentially lead to temporal and spatial variation in hybridization rates in the wild

Vegetable Forcing in Ohio

PDF pages: 3

Strain in wet thermally oxidized square and circular mesas

In this paper, we report the observation, through optical microscopy, of drumhead-like patterns in square and circular mesas which have been wet thermally oxidized to completion. Micro-Raman spectroscopy measurements are used to show that these patterns roughly correspond to variations in strain induced in surrounding semiconductor layers by the oxidation process. In addition, the patterns have a specific orientation with respect to the crystallographic axes of the semiconductor. A crystallographic dependence of the oxidation process itself is demonstrated and used to explain the orientation of the drumhead patterns

Flow of liquids in pipes of circular and annular cross-sections

Cover title.Prepared as part of an investigation conducted by the Engineering Experiment Station, University of Illinois at Urbana-Champaign