3,437 research outputs found

    Exit Wounds Are Big

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    Perceptions of Instructional Coaches and Teachers on the Barriers of Multi-Level Instructional Coaching in Higher Performing vs. Lower Performing Elementary Schools in Tennessee

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    Teacher effectiveness is one of the most influential factors on student achievement. Therefore, it is vitally important to appropriately coach teachers toward increased effectiveness. This qualitative research study explored and compared the types of multi-level instructional coaching utilized within higher performing and lower performing elementary schools throughout Tennessee, as identified by both instructional coaches and classroom teachers. Additionally, participants shared their perceptions of the most beneficial aspects of multi-level instructional coaching and the barriers that hinder its productivity. Lastly, participants shared where they could use additional support in relation to instructional coaching. Data were collected through a researcher-created digital questionnaire, consisting of both open-ended and closed-fixed questions. Data were analyzed through qualitative methods, including coding and thematic development. Responses revealed similarities and differences in the responses of instructional coaches and classroom teachers in higher performing and lower performing schools. Among the findings, participants in higher performance schools emphasized that instructional coaching should be targeted to those specific teachers needing help in a particular area; whereas, the participants from lower performing schools overwhelmingly expressed a desire for coaching to assist toward more clearly understanding the best practices associated with instruction. Results from this study may provide stakeholders with data that could encourage modifications to current instructional coaching methods to improve teacher effectiveness

    Legal Uncertainty and Land Disputes in the Peri-Urban Areas of Mozambique: Land Markets in Transition

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    The Government of Mozambique is considering legal changes in its land law and administration of state leasehold property-an enormous challenge given its past socialist history and the uncertainties created by its current transition to a private market economy. The present research sought to identify dispute causes and de facto processes of dispute resolution as one basis for gauging inadequacies in the current law and system of state land administration.Land Economics/Use,

    Female Adult \u3cem\u3eAedes albopictus\u3c/em\u3e Suppression by \u3cem\u3eWolbachia\u3c/em\u3e-Infected Male Mosquitoes

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    Dengue, chikungunya and zika viruses are pathogens with an increasing global impact. In the absence of an approved vaccine or therapy, their management relies on controlling the mosquito vectors. But traditional controls are inadequate, and the range of invasive species such as Aedes albopictus (Asian Tiger Mosquito) is expanding. Genetically modified mosquitoes are being tested, but their use has encountered regulatory barriers and public opposition in some countries. Wolbachia bacteria can cause a form of conditional sterility, which can provide an alternative to genetic modification or irradiation. It is unknown however, whether openly released, artificially infected male Ae. albopictus can competitively mate and sterilize females at a level adequate to suppress a field population. Also, the unintended establishment of Wolbachia at the introduction site could result from horizontal transmission or inadvertent female release. In 2014, an Experimental Use Permit from the United States Environmental Protection Agency approved a pilot field trial in Lexington, Kentucky, USA. Here, we present data showing localized reduction of both egg hatch and adult female numbers. The artificial Wolbachia type was not observed to establish in the field. The results are discussed in relation to the applied use of Wolbachia-infected males as a biopesticide to suppress field populations of Ae. albopictus

    Early Ordovician Seamounts Preserved in the Canadian Cordillera: Implications for the Rift History of Western Laurentia

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    The breakup of the supercontinent Rodinia and development of the western Laurentian rifted margin are in part recorded by Neoproterozoic to mid-Paleozoic igneous and sedimentary rock successions in the Canadian Cordillera. New bedrock mapping and volcanic facies analysis of Early Ordovician mafic rocks assigned to the Menzie Creek Formation in central Yukon allow reconstruction of the depositional environment during the volcanic eruptions, whole-rock geochemical data constrain the melting depth and crust-mantle source regions of the igneous rocks within the study area, and zircon U-Pb age studies provide determination of the precise timing of submarine eruptions. Menzie Creek Formation volcanic rocks are interlayered with continental slope strata and show lithofacies consistent with those of modern seamount systems. Representative seamount facies contain several kilometers of hyaloclastite breccia and pillow basalt with rare sedimentary rocks. Menzie Creek Formation seamounts form a linear array parallel to the Twopete fault, an ancient extensional or strike-slip fault that localized magmatism along the nascent western Laurentian margin. Zircon grains from two volcanic successions yielded high-precision chemical abrasion–thermal ionization mass spectrometry (CA-TIMS) dates of ca. 484 Ma (Tremadocian), which are interpreted as the age of eruption. Menzie Creek Formation rocks are alkali basalt and have oceanic-island basalt–like geochemical compositions. The whole-rock trace element and Nd-Hf isotope compositions are consistent with the partial melting of subcontinental lithospheric mantle at ~75–100 km depth. Post-rift, Early Ordovician seamounts in central Yukon record punctuated eruptive activity along a rift-related fault, the separation of a continental fragment from western Laurentia, or the oblique post-breakup kinematics from the counterclockwise rotation of Laurentia that facilitated local extension in the passive margin

    Association of endocrine active environmental compounds with body mass index and weight loss following bariatric surgery

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    IntroductionThe objective of this study was to study associations of a wide range of halogenated biphenyls, dibenzo‐p‐dioxins, dibenzofurans, and diphenylethers with body mass index (BMI) and evaluate changes in their concentration following bariatric surgery.MethodsSubcutaneous fat, visceral fat, and liver tissue samples were collected from 106 patients undergoing Roux‐en‐Y gastric bypass surgery for weight loss or patients who were undergoing abdominal surgery for non‐bariatric reasons. We measured concentrations of an extensive panel of chlorinated and brominated biphenyls, dioxins, and furans, and brominated diphenylethers in the samples. We conducted linear regression to examine associations with BMI, adjusting for age and gender. Changes in concentration for indicator chemicals were evaluated in samples collected following bariatric surgery in a small sub‐population.ResultsAfter adjustments for age and gender and correction for multiple testing, seven ortho‐chlorinated biphenyls, one non‐ortho‐chlorinated biphenyl, four PCDD/F’s and one ortho‐brominated biphenyl were associated with BMI. The strongest associations between BMI and lipid‐adjusted concentrations were seen with PCB‐105 in subcutaneous fat (beta=16.838 P‐val=1.45E‐06) PCB‐126 in visceral fat (beta=15.067 P‐val=7.72E‐06) and PCB‐118 (beta=14.101 P‐val=2.66E‐05) in liver. The concentrations of sum PCBs, chlorinated toxic equivalent quantity (TEQ's) and brominated compounds increased significantly with weight loss in subcutaneous fat in a group of ten individuals resampled up to five years after bariatric surgery and substantial weight loss.ConclusionWe show that selected polychlorinated biphenyls PCBs and structurally related polychlorinated dibenzo‐p‐dioxins dibenzofurans (PCDD/Fs) were associated with BMI. Concentrations of these lipophilic compounds in subcutaneous fat increased following bariatric surgery

    Contactless photoconductivity-detected electron spin resonance of P donors in isotopically purified Si

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    Coherence times of electron spins bound to phosphorus donors have been measured, using a standard Hahn echo technique, to be up to 20 ms in isotopically pure silicon with [P]=1014 = 10^{14} cm3^{-3} and at temperatures 4\leq 4 K. Although such times are exceptionally long for electron spins in the solid state, they are nevertheless limited by donor electron spin-spin interactions. Suppressing such interactions requires even lower donor concentrations, which lie below the detection limit for typical electron spin resonance (ESR) spectrometers. Here we describe an alternative method for phosphorus donor ESR detection, exploiting the spin-to-charge conversion provided by the optical donor bound exciton transition. We characterise the method and its dependence on laser power and use it to measure a coherence time of T2=130T_2 = 130 ms for one of the purest silicon samples grown to-date ([P]=5×1011 = 5\times 10^{11} cm3^{-3}). We then benchmark this result using an alternative application of the donor bound exciton transition: optically polarising the donor spins before using conventional ESR detection at 1.7~K for a sample with [P]=4×1012 = 4\times10^{12} cm3^{-3}, and measuring in this case a T2T_2 of 350 ms

    Investigating brain connectivity heritability in a twin study using diffusion imaging data

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    Heritability of brain anatomical connectivity has been studied with diffusion-weighted imaging (DWI) mainly by modeling each voxel's diffusion pattern as a tensor (e.g., to compute fractional anisotropy), but this method cannot accurately represent the many crossing connections present in the brain. We hypothesized that different brain networks (i.e., their component fibers) might have different heritability and we investigated brain connectivity using High Angular Resolution Diffusion Imaging (HARDI) in a cohort of twins comprising 328 subjects that included 70 pairs of monozygotic and 91 pairs of dizygotic twins. Water diffusion was modeled in each voxel with a Fiber Orientation Distribution (FOD) function to study heritability for multiple fiber orientations in each voxel. Precision was estimated in a test-retest experiment on a sub-cohort of 39 subjects. This was taken into account when computing heritability of FOD peaks using an ACE model on the monozygotic and dizygotic twins. Our results confirmed the overall heritability of the major white matter tracts but also identified differences in heritability between connectivity networks. Inter-hemispheric connections tended to be more heritable than intra-hemispheric and cortico-spinal connections. The highly heritable tracts were found to connect particular cortical regions, such as medial frontal cortices, postcentral, paracentral gyri, and the right hippocampus
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