154 research outputs found

    Influences of grazing on habitat characteristics, avian community composition and nesting bird abundance within Cheyenne Bottoms, KS

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    Cheyenne Bottoms is a 41,000-acre prairie-marsh ecosystem in central Kansas. Approximately 8,000 acres of mixed grassland are dedicated for the conservation of bird populations, but little is known about the status of bird communities within these areas. This study took place within grassland areas of Cheyenne Bottoms from May – July 2021. I investigated bird community composition, relative abundance of frequently observed bird species, vegetative characteristics, and similarity of sites across different grazing intensities (continuous, rotational, and non-grazed). The four most common bird species observed were dickcissel (Spiza americana), grasshopper sparrow (Ammodramus savannarum), meadowlark species (Sturnella spp.), and red-winged blackbird (Agelaius phoeniceus). Dickcissel abundances were greatest within non-grazed and rotationally grazed sites. Grasshopper sparrows had the highest abundance in a continuous site with low flooding, moderately high abundance in rotational sites, low abundance in a continuous site with high flooding, and abundance approaching zero in non-grazed sites. Red-winged blackbirds had higher abundances in non-grazed sites than other treatments. Vegetative similarity was generally highest within grazing treatments. Grass height and litter depth were highest at sites of the non-grazed treatment, with similarities across other treatments. Forb comparisons across sites show different distributions for sites of each treatment type, with rotational sites exhibiting a strong right skew and a relatively constrained height range. Presence of sweet clover (Melilotus spp.) was highly apparent at rotational sites within multispectral imagery. Management should continue to maintain pastures with both continuous and rotational grazing regimes

    A comparison of multiple shRNA expression methods for combinatorial RNAi

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    RNAi gene therapies for HIV-1 will likely need to employ multiple shRNAs to counter resistant strains. We evaluated 3 shRNA co-expression methods to determine their suitability for present use; multiple expression vectors, multiple expression cassettes and single transcripts comprised of several dsRNA units (aka domains) with each being designed to a different target. Though the multiple vector strategy was effective with 2 shRNAs, the increasing number of vectors required is a major shortcoming. With single transcript configurations we only saw adequate activity from 1 of 10 variants tested, the variants being comprised of 2 - 3 different target domains. Whilst single transcript configurations have the most advantages on paper, these configurations can not yet be rapidly and reliably re-configured for new targets. However, our multiple cassette combinations of 2, 3 and 4 (29 bp) shRNAs were all successful, with suitable activity maintained in all positions and net activities comparable to that of the corresponding single shRNAs. We conclude that the multiple cassette strategy is the most suitably developed for present use as it is easy to design, assemble, is directly compatible with pre-existing shRNA and can be easily expanded

    Pharmacokinetics and biodistribution of Erufosine in nude mice - implications for combination with radiotherapy

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    <p>Abstract</p> <p>Background</p> <p>Alkylphosphocholines represent promising antineoplastic drugs that induce cell death in tumor cells by primary interaction with the cell membrane. Recently we could show that a combination of radiotherapy with Erufosine, a paradigmatic intravenously applicable alkylphosphocholine, <it>in vitro </it>leads to a clear increase of irradiation-induced cell death. In view of a possible combination of Erufosine and radiotherapy <it>in vivo </it>we determined the pharmacokinetics and bioavailability as well as the tolerability of Erufosine in nude mice.</p> <p>Methods</p> <p>NMRI (nu/nu) nude mice were treated by intraperitoneal or subcutaneous injections of 5 to 40 mg/kg body weight Erufosine every 48 h for one to three weeks. Erufosine-concentrations were measured in brain, lungs, liver, small intestine, colon, spleen, kidney, stomach, adipoid tissue, and muscle by tandem-mass spectroscopy. Weight course, blood cell count and clinical chemistry were analyzed to evaluate general toxicity.</p> <p>Results</p> <p>Intraperitoneal injections were generally well tolerated in all dose groups but led to a transient loss of the bodyweight (<10%) in a dose dependent manner. Subcutaneous injections of high-dose Erufosine caused local reactions at the injection site. Therefore, this regimen at 40 mg/kg body weight Erufosine was stopped after 14 days. No gross changes were observed in organ weight, clinical chemistry and white blood cell count in treated compared to untreated controls except for a moderate increase in lactate dehydrogenase and aspartate-aminotransferase after intensive treatment. Repeated Erufosine injections resulted in drug-accumulation in different organs with maximum concentrations of about 1000 nmol/g in spleen, kidney and lungs.</p> <p>Conclusion</p> <p>Erufosine was well tolerated and organ-concentrations surpassed the cytotoxic drug concentrations <it>in vitro</it>. Our investigations establish the basis for a future efficacy testing of Erufosine in xenograft tumor models in nude mice alone and in combination with chemo- or radiotherapy.</p

    Early cortical surface plasticity relates to basic mathematical learning

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    Children lay the foundation for later academic achievement by acquiring core mathematical abilities in the first school years. Neural reorganization processes associated with individual differences in early mathematical learning, however, are still poorly understood. To fill this research gap, we followed a sample of 5-6-year-old children longitudinally to the end of second grade in school (age 7–8 years) combining magnetic resonance imaging (MRI) with comprehensive behavioral assessments. We report significant links between the rate of neuroplastic change of cortical surface anatomy, and children's early mathematical skills. In particular, most of the behavioral variance (about 73%) of children's visuospatial abilities was explained by the change in cortical thickness in the right superior parietal cortex. Moreover, half of the behavioral variance (about 55%) of children's arithmetic abilities was explained by the change in cortical folding in the right intraparietal sulcus. Additional associations for arithmetic abilities were found for cortical thickness change of the right temporal lobe, and the left middle occipital gyrus. Visuospatial abilities were related to right precentral and supramarginal thickness, as well as right medial frontal gyrus folding plasticity. These effects were independent of other individual differences in IQ, literacy and maternal education. Our findings highlight the critical role of cortical plasticity during the acquisition of fundamental mathematical abilities

    The Hitchhiker\u27s Guide to Europe: the infection dynamics of an ongoing Wolbachia invasion and mitochondrial selective sweep in Rhagoletis cerasi

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    Wolbachia is a maternally inherited and ubiquitous endosymbiont of insects. It can hijack host reproduction by manipulations such as cytoplasmic incompatibility (CI) to enhance vertical transmission. Horizontal transmission of Wolbachia can also result in the colonization of new mitochondrial lineages. In this study, we present a 15-year-long survey of Wolbachia in the cherry fruit fly Rhagoletis cerasi across Europe and the spatiotemporal distribution of two prevalent strains, wCer1 and wCer2, and associated mitochondrial haplotypes in Germany. Across most of Europe, populations consisted of either 100% singly (wCer1) infected individuals with haplotype HT1, or 100% doubly (wCer1&2) infected individuals with haplotype HT2, differentiated only by a single nucleotide polymorphism. In central Germany, singly infected populations were surrounded by transitional populations, consisting of both singly and doubly infected individuals, sandwiched between populations fixed for wCer1&2. Populations with fixed infection status showed perfect association of infection and mitochondria, suggesting a recent CI-driven selective sweep of wCer2 linked with HT2. Spatial analysis revealed a range expansion for wCer2 and a large transition zone in which wCer2 splashes appeared to coalesce into doubly infected populations. Unexpectedly, the transition zone contained a large proportion (22%) of wCer1&2 individuals with HT1, suggesting frequent intraspecific horizontal transmission. However, this horizontal transmission did not break the strict association between infection types and haplotypes in populations outside the transition zone, suggesting that this horizontally acquired Wolbachiainfection may be transient. Our study provides new insights into the rarely studied Wolbachia invasion dynamics in field populations

    Is peer review in academic publishing still working?

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    Peer review is central to academic publishing. Yet for many it is a mysterious and contentious practice, which can cause distress for both reviewers, and those whose work is reviewed. This paper, produced by the Editors’ Collective, examines the past and future of peer review in academic publishing. The first sections consider how peer review has been defined and practised in changing academic contexts, and its educational significance in the development of scholarship. The paper then explores major historical and contemporary issues around identity, diversity, anonymity, and the review process, and the related power of editors versus reviewers in academic publishing. Finally, the paper discusses the case of new scholars as reviewers engaging in neoliberal labour, before concluding with some brief recommendations based on our analysis

    Collective writing: An inquiry into praxis

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    This is the second text in the series collectively written by members of the Editors' Collective, which comprises a series of individual and collaborative reflections upon the experience of contributing to the previous and first text written by the Editors' Collective: 'Towards a Philosophy of Academic Publishing.' In the article, contributors reflect upon their experience of collective writing and summarize the main themes and challenges. They show that the act of collective writing disturbs the existing systems of academic knowledge creation, and link these disturbances to the age of the digital reason. They conclude that the collaborative and collective action is a thing of learning-by-doing, and that collective writing seems to offer a possible way forward from the co-opting of academic activities by economics. Through detaching knowledge creation from economy, collaborative and collective writing address the problem of forming new collective intelligences
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