Examining Spillover Effects from Teach For America Corps Members in Miami-Dade County Public Schools

Despite a large body of evidence documenting the effectiveness of Teach For America (TFA) corps members at raising the math test scores of their students, little is known about the program's impact at the school level. TFA's recent placement strategy in the Miami-Dade County Public Schools (M-DCPS), where large numbers of TFA corps members are placed as clusters into a targeted set of disadvantaged schools, provides an opportunity to evaluate the impact of the TFA program on broader school performance. This study examines whether the influx of TFA corps members led to a spillover effect on other teachers' performance. We find that many of the schools chosen to participate in the cluster strategy experienced large subsequent gains in math achievement. These gains were driven in part by the composition effect of having larger numbers of effective TFA corps members. However, we do not find any evidence that the clustering strategy led to any spillover effect on school-wide performance. In other words, our estimates suggest that extra student gains for TFA corps members under the clustering strategy would be equivalent to the gains that would result from an alternate placement strategy where corps members were evenly distributed across schools

Involvement of NADH Oxidase in Biofilm Formation in Streptococcus sanguinis

Biofilms play important roles in microbial communities and are related to infectious diseases. Here, we report direct evidence that a bacterial nox gene encoding NADH oxidase is involved in biofilm formation. A dramatic reduction in biofilm formation was observed in a Streptococcus sanguinis nox mutant under anaerobic conditions without any decrease in growth. The membrane fluidity of the mutant bacterial cells was found to be decreased and the fatty acid composition altered, with increased palmitic acid and decreased stearic acid and vaccenic acid. Extracellular DNA of the mutant was reduced in abundance and bacterial competence was suppressed. Gene expression analysis in the mutant identified two genes with altered expression, gtfP and Idh, which were found to be related to biofilm formation through examination of their deletion mutants. NADH oxidase-related metabolic pathways were analyzed, further clarifying the function of this enzyme in biofilm formation

Identification of Small-Molecule Inhibitors against Meso-2, 6-Diaminopimelate Dehydrogenase from Porphyromonas gingivalis

Species-specific antimicrobial therapy has the potential to combat the increasing threat of antibiotic resistance and alteration of the human microbiome. We therefore set out to demonstrate the beginning of a pathogen-selective drug discovery method using the periodontal pathogen Porphyromonas gingivalis as a model. Through our knowledge of metabolic networks and essential genes we identified a “druggable” essential target, meso-diaminopimelate dehydrogenase, which is found in a limited number of species. We adopted a high-throughput virtual screen method on the ZINC chemical library to select a group of potential small-molecule inhibitors. Meso-diaminopimelate dehydrogenase from P. gingivaliswas first expressed and purified in Escherichia coli then characterized for enzymatic inhibitor screening studies. Several inhibitors with similar structural scaffolds containing a sulfonamide core and aromatic substituents showed dose-dependent inhibition. These compounds were further assayed showing reasonable whole-cell activity and the inhibition mechanism was determined. We conclude that the establishment of this target and screening strategy provides a model for the future development of new antimicrobials

Influence of Juvenile Wood on Dimensional Stability and Tensile Properties of Flakeboard

The purpose of this study was to determine if juvenile wood adversely affects the linear expansion, water adsorption, and thickness swell of aligned flakeboard. Literature on juvenile wood properties and their effects on product performance was reviewed. Veneer and lumber cut from 35-year-old plantation-grown loblolly pine were segregated by age and used to manufacture plywood and flake-board. As expected, longitudinal linear expansion of the juvenile (0 to 12 years old) veneer was greater than that of mature (13+ years old) veneer. At several levels of humidity exposure, linear expansion of symmetrical cross-laminated plywood made from the juvenile veneer was greater than that of plywood made from mature veneer. Significant increases in the linear expansion of three-layer cross-oriented flakeboard were also attributed to juvenile wood. Differences in the linear expansion of single-layer directional aligned flakeboards made from juvenile wood and from mature wood were not statistically significant for the most part. Analysis did show that test results were affected by tree-to-tree variation in wood age and sample variations. Accurate predictions of dimensional stability in three-layer cross-aligned panels were made using tensile and linear expansion properties derived from the directional flakeboard

Robust Two-Step Wavelet-Based Inference for Time Series Models

Latent time series models such as (the independent sum of) ARMA(p, q) models with additional stochastic processes are increasingly used for data analysis in biology, ecology, engineering, and economics. Inference on and/or prediction from these models can be highly challenging: (i) the data may contain outliers that can adversely affect the estimation procedure; (ii) the computational complexity can become prohibitive when the time series are extremely large; (iii) model selection adds another layer of (computational) complexity; and (iv) solutions that address (i), (ii), and (iii) simultaneously do not exist in practice. This paper aims at jointly addressing these challenges by proposing a general framework for robust two-step estimation based on a bounded influence M-estimator of the wavelet variance. We first develop the conditions for the joint asymptotic normality of the latter estimator thereby providing the necessary tools to perform (direct) inference for scale-based analysis of signals. Taking advantage of the model-independent weights of this first-step estimator, we then develop the asymptotic properties of two-step robust estimators using the framework of the generalized method of wavelet moments (GMWM). Simulation studies illustrate the good finite sample performance of the robust GMWM estimator and applied examples highlight the practical relevance of the proposed approach

Forward-Backward splitting methods for accretive operators in Banach spaces

Splitting methods have recently received much attention due to the fact that many nonlinear problems arising in applied areas such as image recovery, signal processing, and machine learning are mathematically modeled as a nonlinear operator equation and this operator is decomposed as the sum of two (possibly simpler) nonlinear operators. Most of the investigation on splitting methods is however carried out in the framework of Hilbert spaces. In this paper, we consider these methods in the setting of Banach spaces. We shall introduce two iterative forward-backward splitting methods with relaxations and errors to find zeros of the sum of two accretive operators in the Banach spaces. We shall prove the weak and strong convergence of these methods under mild conditions. We also discuss applications of these methods to variational inequalities, the split feasibility problem, and a constrained convex minimization problem

An updated interactive database for 1692 genetic variants in coagulation Factor IX provides detailed insights into haemophilia B

BACKGROUND: Genetic variants in coagulation factor IX (FIX) are associated with haemophilia B, a rare bleeding disease. F9 variants are widespread across the gene and were summarised in our FIX variant database introduced in 2013. OBJECTIVE: We rationalise the molecular basis for 598 new F9 variants and 1645 new clinical cases, making a total of 1692 F9 variants and 5358 related patient cases. METHODS: New F9 variants were identified from publications and on-line resources, and compiled into a MySQL database for comparison with the human FIXa protein structure. RESULTS: The new total of 1692 F9 variants correspond to 406 (88%) of the 461 FIX residues and now include 70 additional residues. These comprise 945 unique point variants, 281 deletions, 352 polymorphisms, 63 insertions, and 51 others. Most FIX variants were point variants, although their proportion (56%) has reduced compared to 2013 (73%), while the proportion of polymorphisms has increased from 5% to 21%.The 764 unique mild severity variants in the mature protein with known phenotypes include 74 (9.7%) quantitative type I variants and 116 (15.2%) predominantly qualitative type II variants. The remaining 574 variants types are unspecified. Inhibitors are associated with 152 haemophilia B cases out of 5358 patients (2.8%), an increase of 93 from the previous database. CONCLUSION: The even distribution of the F9 variants revealed few mutational hotspots, and most variants were associated with small perturbations in the FIX protein structure. The updated database will assist clinicians and researchers in assessing treatments for haemophilia B patients

Mortality Analyses on Systemic Corticosteroid Use : a Long-term Observational Study

Peer reviewe

Spectral and Timing Properties of IGR J17091-3624 in the Rising Hard State During its 2016 Outburst

We present a spectral and timing study of the NuSTAR and Swift observations of the black hole candidate IGR J17091-3624 in the hard state during its outburst in 2016. Disk reflection is detected in each of the NuSTAR spectra taken in three epochs. Fitting with relativistic reflection models reveals that the accretion disk is truncated during all epochs with $R_{\rm in}>10~r_{\rm g}$, with the data favoring a low disk inclination of $\sim 30^{\circ}-40^{\circ}$. The steepening of the continuum spectra between epochs is accompanied by a decrease in the high energy cut-off: the electron temperature $kT_{\rm e}$ drops from $\sim 64$ keV to $\sim 26$ keV, changing systematically with the source flux. We detect type-C QPOs in the power spectra with frequency varying between 0.131 Hz and 0.327 Hz. In addition, a secondary peak is found in the power spectra centered at about 2.3 times the QPO frequency during all three epochs. The nature of this secondary frequency is uncertain, however a non-harmonic origin is favored. We investigate the evolution of the timing and spectral properties during the rising phase of the outburst and discuss their physical implications.Comment: 11 pages, 9 figures, accepted by Ap

A State-of-the-Art Review of Laser-Assisted Bioprinting and its Future Research Trends

Bioprinting is an additive manufacturing technology with great potential in medical applications. Among available bioprinting techniques, laser-assisted bioprinting (LAB) is a promising technique due to its high resolution, high cell viability, and the capability to deposit high-viscousity bioink. These characteristics allow the LAB technology to control cells precisely to reconstruct living organs. Recent developments of LAB technologies are reviewed in this paper, covering various designs of LAB printers, research progresses in energy-absorbing layer (EAL), the physical phenomenon that triggers the printing process in terms of bubble formation and jet development, printing process parameters, and major factors related to the post-printing cell viability. The latest studies on LAB technologies are highlighted, expounding their advantages and disadvantages, and some potential applications are presented. The potential technical challenges and future research trends for LAB technologies are also discussed