The Effects of Teaching Text Structures Through Social Studies Content on Second Graders\u27 Expository Reading Comprehension

The purpose of the study was to determine the effect of explicitly teaching expository text structure on second graders\u27 social studies reading comprehension. Participants were 18 second graders from a small Midwestern town. All students were part of the same treatment group. The researcher instructed students on how to identify and comprehend compare/contrast and cause/effect expository text structure. The instruction for the text structures occurred for three weeks each for a total of a six week study. The researcher instructed students with modeling, guided practice and independent practice through the use of graphic organizers. Findings suggested very little effect of treatment. Several strengths and limitations of the study are discussed, as well as implications for future research

Drosophila host defense: differential induction of antimicrobial peptide genes after infection by various classes of microorganisms

Insects respond to microbial infection by the rapid and transient expression of several genes encoding potent antimicrobial peptides. Herein we demonstrate that this antimicrobial response of Drosophila is not aspecific but can discriminate between various classes of microorganisms. We first observe that the genes encoding antibacterial and antifungal peptides are differentially expressed after injection of distinct microorganisms. More strikingly, Drosophila that are naturally infected by entomopathogenic fungi exhibit an adapted response by producing only peptides with antifungal activities. This response is mediated through the selective activation of the Toll pathway

Redroot pigweed (Amaranthus retroflexus L.) and lamb's quarters ‎‎(Chenopodium album L.) populations exhibit a high degree of ‎morphological and biochemical diversity

Amaranthus retroflexus L. and Chenopodium album L. are noxious weeds that have a cosmopolitan distribution. These species successfully invade and are adapted to a wide variety of diverse climates. In this paper we evaluated the morphology and biochemistry of 16 populations of A. retroflexus L. and 17 populations of C. album L.. Seeds from populations collected from Spain, France and Iran were grown together at the experimental field of the agriculture research of University of Mohaghegh Ardabili and a suite of morphological traits and biochemical traits were assessed. Among the populations of A. retroflexus L. and of C. album L. were observed significant differences for all the measured traits. The number of branches for A. retroflexus L. (12.22) and inflorescence length (14.34) for C. album L. were the two characteristics that exhibited the maximum coefficient of variation. Principal component analysis of these data identified four principal components for each species that explained 83.54 (A. retroflexus L.) and 88.98 (C. album L.) of the total variation. A dendrogram based on unweighted neighbor-joining method clustered all the A. retroflexus L. and C. album L. into two main clusters and four sub-clusters. Canonical correlation analysis was used to evaluate relationships between climate classification of origin and traits. Similarly, the measured characteristics did not group along Köppen climate classification. Both analyses support the conclusion that A. retroflexus L. and C. album L. exhibit high levels of diversity despite similar environmental histories. Both species also exhibit a high diversity of the measured biochemical compounds indicating they exhibit different metabolic profiles even when grown concurrently and sympatrically. Several of the biochemical constituents identified in our study could serve as effective indices for indirect selection of stresses resistance/tolerance of A. retroflexus L. and C. album L. The diversity of the morphological and biochemical traits observed among these populations illustrates how the unique selection pressures faced by each population can alter the biology of these plants. This understanding provides new insights to how these invasive plant species successfully colonize diverse ecosystems and suggests methods for their management under novel and changing environmental conditions

In vivo regulation of the IkappaB homologue cactus during the immune response of Drosophila

The dorsoventral regulatory gene pathway (spätzle/Toll/cactus) controls the expression of several antimicrobial genes during the immune response of Drosophila. This regulatory cascade shows striking similarities with the cytokine-induced activation cascade of NF-kappaB during the inflammatory response in mammals. Here, we have studied the regulation of the IkappaB homologue Cactus in the fat body during the immune response. We observe that the cactus gene is up-regulated in response to immune challenge. Interestingly, the expression of the cactus gene is controlled by the spätzle/Toll/cactus gene pathway, indicating that the cactus gene is autoregulated. We also show that two Cactus isoforms are expressed in the cytoplasm of fat body cells and that they are rapidly degraded and resynthesized after immune challenge. This degradation is also dependent on the Toll signaling pathway. Altogether, our results underline the striking similarities between the regulation of IkappaB and cactus during the immune response

Aborted microspores acts as a master regulator of pollen wall formation in Arabidopsis

Mature pollen is covered by durable cell walls, principally composed of sporopollenin, an evolutionary conserved, highly resilient, but not fully characterized, biopolymer of aliphatic and aromatic components. Here, we report that ABORTED MICROSPORES (AMS) acts as a master regulator coordinating pollen wall development and sporopollenin biosynthesis in Arabidopsis thaliana. Genome-wide coexpression analysis revealed 98 candidate genes with specific expression in the anther and 70 that showed reduced expression in ams. Among these 70 members, we showed that AMS can directly regulate 23 genes implicated in callose dissociation, fatty acids elongation, formation of phenolic compounds, and lipidic transport putatively involved in sporopollenin precursor synthesis. Consistently, ams mutants showed defective microspore release, a lack of sporopollenin deposition, and a dramatic reduction in total phenolic compounds and cutin monomers. The functional importance of the AMS pathway was further demonstrated by the observation of impaired pollen wall architecture in plant lines with reduced expression of several AMS targets: the abundant pollen coat protein extracellular lipases (EXL5 and EXL6), and CYP98A8 and CYP98A9, which are enzymes required for the production of phenolic precursors. These findings demonstrate the central role of AMS in coordinating sporopollenin biosynthesis and the secretion of materials for pollen wall patterning

WIMP-nucleon cross-section results from the second science run of ZEPLIN-III

We report experimental upper limits on WIMP-nucleon elastic scattering cross sections from the second science run of ZEPLIN-III at the Boulby Underground Laboratory. A raw fiducial exposure of 1,344 kg.days was accrued over 319 days of continuous operation between June 2010 and May 2011. A total of eight events was observed in the signal acceptance region in the nuclear recoil energy range 7-29 keV, which is compatible with background expectations. This allows the exclusion of the scalar cross-section above 4.8E-8 pb near 50 GeV/c^2 WIMP mass with 90% confidence. Combined with data from the first run, this result improves to 3.9E-8 pb. The corresponding WIMP-neutron spin-dependent cross-section limit is 8.0E-3 pb. The ZEPLIN programme reaches thus its conclusion at Boulby, having deployed and exploited successfully three liquid xenon experiments of increasing reach

Measurement and simulation of the muon-induced neutron yield in lead

A measurement is presented of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850m water equivalent (w.e.) and a mean muon energy of 260GeV. The measurement exploits the delayed coincidences between muons and the radiative capture of induced neutrons in a highly segmented tonne scale plastic scintillator detector. Detailed Monte Carlo simulations reproduce well the measured capture times and multiplicities and, within the dynamic range of the instrumentation, the spectrum of energy deposits. By comparing measurements with simulations of neutron capture rates a neutron yield in lead of (5.78_-_0_._2_8^+^0^.^2^1) x10^-^3neutrons/muon/(g/cm^2) has been obtained. Absolute agreement between simulation and data is of order 25%. Consequences for deep underground rare event searches are discussed.Peer Reviewe

Quenching Factor for Low Energy Nuclear Recoils in a Plastic Scintillator

Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear recoils in a polystyrene-based plastic scintillator (UPS-923A) is presented, exploring recoil energies between 125 keV and 850 keV. Monte Carlo simulations, incorporating light collection efficiency and energy resolution effects, are used to generate neutron scattering spectra which are matched to observed distributions of scintillation signals to parameterise the energy-dependent quenching factor. At energies above 300 keV the dependence is reasonably described using the semi-empirical formulation of Birks and a kB factor of (0.014+/-0.002) g/MeVcm^2 has been determined. Below that energy the measured quenching factor falls more steeply than predicted by the Birks formalism.Comment: 8 pages, 9 figure