3,070 research outputs found
A Comparison of the Academic Achievements of Intermediate Students Based on Socioeconomic Status and Participation in an After-School Program.
The purpose of this study was to determine what, if any, associations exist between students\u27 academic success on achievement tests and the predictor variables of students\u27 socioeconomic status, participation in an after-school program, and gender. Middlesboro Intermediate School contains a high number of students who participate in the federal free- or reduced-price school meals program, as well as attend the after-school program. This study factored in the student\u27s academic success on the Kentucky Core Content Test and the socioeconomic status of students based on their qualification for the federal free- or reduced-cost school meals program, their participation in the after-school program, and their gender. This study was based on test results for students in the fourth grade in the areas of math, science, reading, writing on demand, and writing portfolio, as well as the test results for the fifth-grade students in the areas of arts and humanities, practical living-vocational studies, social studies, math, and reading. The entire school population was included except for students never attending the after-school program and students receiving testing modifications on the Kentucky Core Content Test.
Based on the analysis of the data and findings of this study, the implementation of an after-school program appears to have benefits for all students regardless of socioeconomic status; however, student success differs by content areas and the number of days of attendance in the after-school program
Private vs. Public Regulation: Political Economy of the International Environment
Minimum standards set by a ‘World Environmental Organisation’ (WEO) and NGO labelling are promoted as alternative approaches to international environmental protection. We explore the potential inter-play between these two approaches when the WEO is subject to pressure from producers. We find that if WEO and NGO schemes are mutually exclusive then the existence of an NGO ‘alternative’ increases industry resistance to WEO proposals and this may reduce welfare. If, however, the schemes are run in parallel, existence of the NGO lessens producer opposition to WEO activities. This allows the WEO to be ‘bolder’ in its proposals, which is good for welfare
Design and Simulation of the Internet of Things for Accra Smart City
The Internet of Things (IoT) concept of connecting objects with IP address to a network has many significant applications such as smart health, smart cities, and smart energy. This study focuses on the use of Internet of Things for smart cities and its advantages. In this paper our main goal is to model and simulate an IoT system for Accra smart city that uses smart webcams with IP address that are addressable to allow these smart webcam transmit valuable information to users. The designed smart city will address a challenge by giving live feeds on traffic situations and flooding on major routes to people. We used cisco packet tracer to model and simulate the IoT network where smart webcams can remotely transmit data packets. The results of the simulation indicates that when the smart webcam are connected in a wireless medium, they can send and receive data packets via a 6LowPAN gateway which can be access by users in the Internet. Keywords:Internet of Things, Smart City, Smart Webca
A monoclonal antibody that inhibits mycobacterial DNA gyrase by a novel mechanism
DNA gyrase is a DNA topoisomerase indispensable for cellular functions in bacteria. We describe a novel, hitherto unknown, mechanism of specific inhibition of Mycobacterium smegmatis and Mycobacterium tuberculosis DNA gyrase by a monoclonal antibody (mAb). Binding of the mAb did not affect either GyrA–GyrB or gyrase–DNA interactions. More importantly, the ternary complex of gyrase–DNA–mAb retained the ATPase activity of the enzyme and was competent to catalyse DNA cleavage–religation reactions, implying a new mode of action different from other classes of gyrase inhibitors. DNA gyrase purified from fluoroquinolone-resistant strains of M.tuberculosis and M.smegmatis were inhibited by the mAb. The absence of cross-resistance of the drug-resistant enzymes from two different sources to the antibody-mediated inhibition corroborates the new mechanism of inhibition. We suggest that binding of the mAb in the proximity of the primary dimer interface region of GyrA in the heterotetrameric enzyme appears to block the release of the transported segment after strand passage, leading to enzyme inhibition. The specific inhibition of mycobacterial DNA gyrase with the mAb opens up new avenues for designing novel lead molecules for drug discovery and for probing gyrase mechanism
Detection of Multi-drug Resistant \u3cem\u3eEscherichia coli\u3c/em\u3e in the Urban Waterways of Milwaukee, WI
Urban waterways represent a natural reservoir of antibiotic resistance which may provide a source of transferable genetic elements to human commensal bacteria and pathogens. The objective of this study was to evaluate antibiotic resistance of Escherichia coli isolated from the urban waterways of Milwaukee, WI compared to those from Milwaukee sewage and a clinical setting in Milwaukee. Antibiotics covering 10 different families were utilized to determine the phenotypic antibiotic resistance for all 259 E. coli isolates. All obtained isolates were determined to be multi-drug resistant. The E. coli isolates were also screened for the presence of the genetic determinants of resistance including ermB (macrolide resistance), tet(M) (tetracycline resistance), and β-lactamases (blaOXA, blaSHV, and blaPSE). E. coli from urban waterways showed a greater incidence of antibiotic resistance to 8 of 17 antibiotics tested compared to human derived sources. These E. coli isolates also demonstrated a greater incidence of resistance to higher numbers of antibiotics compared to the human derived isolates. The urban waterways demonstrated a greater abundance of isolates with co-occurrence of antibiotic resistance than human derived sources. When screened for five different antibiotic resistance genes conferring macrolide, tetracycline, and β-lactam resistance, clinical E. coli isolates were more likely to harbor ermB and blaOXA than isolates from urban waterway. These results indicate that Milwaukee’s urban waterways may select or allow for a greater incidence of multiple antibiotic resistance organisms and likely harbor a different antibiotic resistance gene pool than clinical sources. The implications of this study are significant to understanding the presence of resistance in urban freshwater environments by supporting the idea that sediment from urban waterways serves as a reservoir of antibiotic resistance
VUV Optical Properties of Rare Earth Doped YPO4 Prepared by Different Routes
The optical properties of nanocrystalline YPO4:Ln3+ (Ln = Eu, Sm, Tb) prepared via co-precipitation are compared to larger crystallites of YPO4:Ln3+ prepared via traditional solid state reaction. In larger crystals (~330 nm) a distinct peak is observed at 150 nm in the excitation spectra, the intensity of which decreases markedly in smaller crystals (~20 nm). Using excitation and reflectance spectroscopy, host–to–activator energy transfer efficiencies were calculated for Y1-xPO4:Lnx3+ (0.01 ≤ x ≤ 0.10). From the transfer efficiency data, we estimate that trapping by Eu3+ and Sm3+ is at least five times more efficient than trapping by Tb3+ for excitation at the band edge. The fraction of energy lost to the surface or grain boundaries for excitation at 150 nm and 138 nm is also estimated. We propose that in the samples prepared via co-precipitation, an amorphous phase forms at grain boundaries that is responsible for the loss of efficiency under 150 nm excitation
Habitable Climate Scenarios for Proxima Centauri b With a Dynamic Ocean
The nearby exoplanet Proxima Centauri b will be a prime future target for
characterization, despite questions about its retention of water. Climate
models with static oceans suggest that an Earth-like Proxima b could harbor a
small dayside region of surface liquid water at fairly warm temperatures
despite its weak instellation. We present the first 3-dimensional climate
simulations of Proxima b with a dynamic ocean. We find that an ocean-covered
Proxima b could have a much broader area of surface liquid water but at much
colder temperatures than previously suggested, due to ocean heat transport and
depression of the freezing point by salinity. Elevated greenhouse gas
concentrations do not necessarily produce more open ocean area because of
possible dynamic regime transitions. For an evolutionary path leading to a
highly saline present ocean, Proxima b could conceivably be an inhabited,
mostly open ocean planet dominated by halophilic life. For an ocean planet in
3:2 spin-orbit resonance, a permanent tropical waterbelt exists for moderate
eccentricity. Simulations of Proxima Centauri b may also be a model for the
habitability of planets receiving similar instellation from slightly cooler or
warmer stars, e.g., in the TRAPPIST-1, LHS 1140, GJ 273, and GJ 3293 systems.Comment: Submitted to Astrobiology; 38 pages, 12 figures, 5 table
Craniodental Adaptation and Homoplasy in Early Mammals
For the first two-thirds of their over 180-million-year history, mammals left a sparse fossil record. Often the only direct evidence of these early forms are small and unassociated craniodental fragments. Despite these limitations, the three chapters of this thesis support the effectiveness of this type of material for estimating the functional and autecological capacities in Mesozoic mammals, through high resolution imaging and morphometric analysis of the molariform dentition.
Each of the three chapters is a self-contained study addressing separate topics relating to the evolution of dental and petrosal morphology. The common thread between all sections is that variation in craniodental structure among Mesozoic lineages is greater than would be expected based only on the disparity seen among extant small mammals. This is a result of both the more “modern” dynamics of dental evolution in more Mesozoic mammalian lineages than historically appreciated (Chapters 1 and 3), and the more “primitive” morphology of the inner ear, even in groups very closely related to extant crown therians (Chapter 2). In both cases, the craniodental morphologies described are outside the range of variation seen in extant species.
Chapter 1 describes several new specimens from the herbivorous stem-therian mammal Reigitherium, from the Late Cretaceous of Patagonia. These newly available specimens demonstrate that the herbivorous molar morphology seen in Reigitherium is derived from the more plesiomorphic tuberculosectorial pattern seen in the South American endemic group Meridiolestida.
Chapter 2 presents descriptions and analysis of the internal structure of three stem therian petrosal bones from the Late Jurassic of North America, and middle Cretaceous of Mongolia. Within the comparative context of labyrinthine endocast evolution, it can be determined that many of the advanced features of modern therian hearing likely developed only after their divergence from their common ancestor with the fossil groups described here.
Finally, Chapter 3 presents a macroevolutionary analysis of lower molariform shape change across a large sample of early mammaliaforms, using high-level morphometric methods. The results of this analysis suggest that the stochastic processes controlling the shape evolution of lower molariforms in crown Mammalia are shared across a wide range of “triconodont”, “symmetrodont”, and “tribosphenic” Mesozoic taxa
Complex genetic association of 6q23 with autoimmune rheumatic conditions
In the paper by Dieguez-Gonzalez and colleagues in the present issue of Arthritis Research & Therapy, the results of a detailed genetic investigation of the recently identified rheumatoid arthritis and systemic lupus erythematosus susceptibility region at 6q23 containing the TNFAIP3 gene are reported. Their data confirm the complex nature of the association involving both the TNFAIP3 locus and a region >150 kb upstream that does not encode any known gene. These data are consistent with recent studies of systemic lupus erythematosus susceptibility confirming the presence of several independent genetic contributions to autoimmune rheumatic diseases arising from 6q23
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