325 research outputs found

    Second grade ELL\u27s emic perspective of an afterschool reading program: an interactional ethnographic study of reading opportunities and social construction of second grade ELL\u27s read alouds

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    The purpose of this research was to uncover what counts as reading to second grade ELLs (English Language Learners) in a non-graded, afterschool reading program. I used an interactional ethnographic epistemological research approach. I video-and audio-taped twentyfour afterschool reading lessons, took fieldnotes, conducted semi-structured interviews, and collected artifacts. The thirteen participants were ELLs, from low socioeconomic backgrounds, and of Mexican-American descent. First, I identified children’s opportunities on an event map. Next, I analyzed moment-by-moment discourse analysis of read alouds from the beginning and end of the program. Finally, I made visible what counted as reading from participants’ discourse through domain analyses and taxonomy. Findings of the study demonstrate three key signals of what counts as reading to the children: sharing knowledge, responding to texts, and recognizing norms and expectations of the classroom. To students, reading is done collectively, texts are used to do something, and reading is for making personal meaning beyond literal interpretations. Students use classroom’s reading contexts as opportunities for student agency, for constructing and reconstructing cultural and reading norms and expectations, and for understanding and doing reading creatively in ways that extend beyond those beyond predetermined by the teacher or influenced by policies and contexts outside the classroom. Informed by the research findings, curriculum administrators, teachers, and students are encouraged to plan, implement, and take up opportunities to promote opportunities for socially constructing reading

    How Varroa Parasitism affects the immunological and nutritional status of the honey bee, Apis mellifera

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    We investigated the effect of the parasitic mite Varroa destructor on the immunological and nutritional condition of honey bees, Apis mellifera, from the perspective of the individual bee and the colony. Pupae, newly-emerged adults and foraging adults were sampled from honey bee colonies at one site in S. Texas, USA. Varroa infested bees displayed elevated titer of Deformed Wing Virus (DWV), suggestive of depressed capacity to limit viral replication. Expression of genes coding three anti-microbial peptides (defensin1, abaecin, hymenoptaecin) was either not significantly different between Varroa-infested and uninfested bees or was significantly elevated in Varroa-infested bees, varying with sampling date and bee developmental age. The effect of Varroa on nutritional indices of the bees was complex, with protein, triglyceride, glycogen and sugar levels strongly influenced by life-stage of the bee and individual colony. Protein content was depressed and free amino acid content elevated in Varroa-infested pupae, suggesting that protein synthesis, and consequently growth, may be limited in these insects. No simple relationship between the values of nutritional and immune-related indices was observed, and colony-scale effects were indicated by the reduced weight of pupae in colonies with high Varroa abundance, irrespective of whether the individual pupa bore Varroa

    Physical Properties and Chemical Characterization of Macro- and Micro-Nutriments of Elite Blue Maize Hybrids (Zea mays L.)

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    Five elite blue maize hybrids and two blue maize landraces were evaluated for various quality characteristics. Hybrids showed physical characteristics demanded by dry-millers and tortilla processors: above 290 g in one hundred-kernel weight test, higher test weight (76.1–78.5 kg hl−1) and lower flotation index (22–61%). Hybrid maize 613 × 27 (9.9%) and 611 × 8 (9.5%) contained the highest protein. Potassium, magnesium, manganese and zinc contents of hybrid maize were higher than landraces by 15, 30, 55 and 41%, respectively. Nutrimental profile showed linoleic acid contents above 50% in 503 × 67, 613 × 27 and 611 × 8 hybrid samples. Lysine levels of landraces and hybrids 503 × 67 (33.9 g kg−1 protein) and 631 × 27 (31.7 g kg−1 protein) were higher than reported for regular white corn (27 g kg−1 protein), as well as the highest tryptophan levels for Chalqueno (6.0 g kg−1 protein) and hybrid 503 × 67 (6.9 g kg−1 protein). Highest protein quality based on its digestibility was found in hybrid 503 × 67. Results indicated that elite blue maize hybrids could be an important source of nutrimental compounds with potential for functional food industries

    Identification of superior doubled haploid maize (Zea mays) inbred lines derived from high oil content subtropical populations

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    High oil maize (HOM) hybrids, adapted to subtropical regions are needed to meet existing requirements forindustrial and livestock purposes. Recently, the doubled haploid (DH) breeding technology is applied to reduceconsiderably the time to generate homozygous maize lines, however, information of heterotic response, per seproductivity, stress, disease reaction, and adaptation to different environments are not known. In this work, fieldevaluations of per se and testcross high oil content DH lines adapted for subtropical environments were studiedto identify superior DH lines with good heterotic response and agronomic characteristics. White and yellow kerneltest crosses were formed using the different heterotic population as testers from which DH lines were derived.Test crosses were evaluated at three locations in Mexico. Superior DH lines from each tester presented highGCA effects through test crosses, with a range of grain yield across locations of 12.8 to 10.4 Mg ha-1 and 11.1to 9.1 Mg ha-1 respectively. Per se DH lines were observed and screened for adaptation, productivity, diseasereaction and other agronomic traits in five locations/year environments. Per se DH lines screening process acrossenvironments was able to obtain information for adaptation, productivity, and healthiness. Also of DH lines withhigh response of GCA, information regarding heterotic groups, and DH lines oil content determination was usedto identify outstanding DH lines for developing HOM high-yielding hybrids adapted for subtropical regions, withfewer costs and time. This research demonstrated that it was feasible to identify subtropical elite DH lines withhigh oil content

    Large male proboscis monkeys have larger noses but smaller canines

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    The uniquely enlarged noses of male proboscis monkeys are prominent adornments, and a sexually selected male trait. A recent study showed significant correlations among nose, body, and testis sizes and clear associations between nose size and the number of females in a male’s harem. However, to date, the analyses of other common male traits, i.e., canines, are lacking. Whereas male nose size had a positive correlation with body size, we unexpectedly found a negative correlation between body and canine sizes. We explain this by an interaction between sexual and natural selection. Larger noses in males may interfere with the use of canines, thereby reducing their effectiveness as weapons. Additionally, longer canines are opposed by natural selection because the larger gape it imposes upon its bearer reduces foraging efficiency, particularly in folivores. This unique case of decoupling of body and canine size reveals that large canines carry an ecological cost

    ATAD5 promotes replication restart by regulating RAD51 and PCNA in response to replication stress

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    Maintaining stability of replication forks is important for genomic integrity. However, it is not clear how replisome proteins contribute to fork stability under replication stress. Here, we report that ATAD5, a PCNA unloader, plays multiple functions at stalled forks including promoting its restart. ATAD5 depletion increases genomic instability upon hydroxyurea treatment in cultured cells and mice. ATAD5 recruits RAD51 to stalled forks in an ATR kinase-dependent manner by hydroxyurea-enhanced protein-protein interactions and timely removes PCNA from stalled forks for RAD51 recruitment. Consistent with the role of RAD51 in fork regression, ATAD5 depletion inhibits slowdown of fork progression and native 5-bromo-2??-deoxyuridine signal induced by hydroxyurea. Single-molecule FRET showed that PCNA itself acts as a mechanical barrier to fork regression. Consequently, DNA breaks required for fork restart are reduced by ATAD5 depletion. Collectively, our results suggest an important role of ATAD5 in maintaining genome integrity during replication stress

    Small-Scale Extrusion of Corn Masa By-Products

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    Corn masa by-product streams are high in fiber and are amenable for utilization in livestock feed rations. This approach is a potentially viable alternative to landfilling, the traditional disposal method for these processing residues. Suspended solids were separated from a masa processing waste stream, blended with soybean meal at four levels (0, 10, 20, and 30% wb), and extruded in a laboratory-scale extruder at speeds of 50 rpm (5.24 rad/sec) and 100 rpm (10.47 rad/sec) with temperature profiles of 80-90-100°C and 100-110-120°C. Processing conditions, including dough and die temperatures, drive torque, specific mechanical energy consumption, product and feed material throughput rates, dough apparent viscosity, and dough density, were monitored during extrusion. The resulting products were subjected to physical and nutritional characterization to determine the effects of processing conditions for these blends. Extrudate analysis included moisture content, water activity, crude protein, in vitro protein digestibility, crude fat, ash, product diameter, expansion ratios, unit and true density, color, water absorption and solubility, and durability. All blends were suitable for extrusion at the processing conditions used. Blend ratio had little effect on either processing parameters or extrudate properties; extrusion temperature and screw speed, on the other hand, significantly affected both processing and product properties

    Abnormal blood flow in the sublingual microcirculation at high altitude

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    We report the first direct observations of deranged microcirculatory blood flow at high altitude, using sidestream dark-field imaging. Images of the sublingual microcirculation were obtained from a group of 12 volunteers during a climbing expedition to Cho Oyu (8,201 m) in the Himalayas. Microcirculatory flow index (MFI) was calculated from the moving images of microcirculatory red blood cell flow, and comparison was made between the baseline and high altitude measurements. Peripheral oxygen saturation (SpO2) and Lake Louise scores (LLS) were recorded along with MFI. Our data demonstrate that there was a significant reduction in MFI from baseline to 4,900 m in small (less than 25 μm) and medium (26–50 μm) sized blood vessels (P = 0.025 and P = 0.046, respectively). There was no significant correlation between MFI and SpO2 or MFI and LLS. Disruption of blood flow within microcirculatory may explain persistent abnormal oxygen flux to tissues following the normalisation of systemic oxygen delivery that accompanies acclimatisation to high altitude
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