60 research outputs found

    Calculating all elements of minimal index in the infinite parametric family of simplest quartic fields

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    summary:It is a classical problem in algebraic number theory to decide if a number field is monogeneous, that is if it admits power integral bases. It is especially interesting to consider this question in an infinite parametric family of number fields. In this paper we consider the infinite parametric family of simplest quartic fields KK generated by a root ξ\xi of the polynomial Pt(x)=x4tx36x2+tx+1P_t(x)=x^4-tx^3-6x^2+tx+1, assuming that t>0t>0, t3t\neq 3 and t2+16t^2+16 has no odd square factors. In addition to generators of power integral bases we also calculate the minimal index and all elements of minimal index in all fields in this family

    Comparative effectiveness of asthma interventions within a practice based research network

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    <p>Abstract</p> <p>Background</p> <p>Asthma is a chronic lung disease that affects more than 23 million people in the United States, including 7 million children. Asthma is a difficult to manage chronic condition associated with disparities in health outcomes, poor medical compliance, and high healthcare costs. The research network coordinating this project includes hospitals, urgent care centers, and outpatient clinics within Carolinas Healthcare System that share a common electronic medical record and billing system allowing for rapid collection of clinical and demographic data. This study investigates the impact of three interventions on clinical outcomes for patients with asthma. Interventions are: an integrated approach to care that incorporates asthma management based on the chronic care model; a shared decision making intervention for asthma patients in underserved or disadvantaged populations; and a school based care approach that examines the efficacy of school-based programs to impact asthma outcomes including effectiveness of linkages between schools and the healthcare providers.</p> <p>Methods/Design</p> <p>This study will include 95 Practices, 171 schools, and over 30,000 asthmatic patients. Five groups (A-E) will be evaluated to determine the effectiveness of three interventions. Group A is the usual care control group without electronic medical record (EMR). Group B practices are a second control group that has an EMR with decision support, asthma action plans, and population reports at baseline. A time delay design during year one converts practices in Group B to group C after receiving the integrated approach to care intervention. Four practices within Group C will receive the shared decision making intervention (and become group D). Group E will receive a school based care intervention through case management within the schools. A centralized database will be created with the goal of facilitating comparative effectiveness research on asthma outcomes specifically for this study. Patient and community level analysis will include results from patient surveys, focus groups, and asthma patient density mapping. Community variables such as income and housing density will be mapped for comparison. Outcomes to be measured are reduced hospitalizations and emergency department visits; improved adherence to medication; improved quality of life; reduced school absenteeism; improved self-efficacy and improved school performance.</p> <p>Discussion</p> <p>Identifying new mechanisms that improve the delivery of asthma care is an important step towards advancing patient outcomes, avoiding preventable Emergency Department visits and hospitalizations, while simultaneously reducing overall healthcare costs.</p

    Ungulate browsing shapes climate change impacts on forest biodiversity in Hungary

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    Climate change can result in a slow disappearance of forests dominated by less drought-tolerant native European beech (Fagus sylvatica) and oak species (Quercus spp.) and further area expansion of more drought-tolerant non-native black locust (Robinia pseudoacacia) against those species in Hungary. We assumed that the shift in plant species composition was modified by selective ungulate browsing. Thus, we investigated which woody species are selected by browsing game. We have collected data on the species composition of the understory and the browsing impact on it in five different Hungarian even-aged forests between 2003 and 2005. Based on these investigations the non-native Robinia pseudoacacialiving under more favourable climatic conditions was generally preferred (Jacobs’ selectivity index: D=0.04±0.77), while the nativeFagus sylvatica and Quercus spp. (Q. petraea, Q. robur), both more vulnerable to increasing aridity, were avoided (D=-0.37±0.11;-0.79±0.56;-0.9±0.16; respectively) among target tree species. However, economically less or not relevant species, e.g. elderberry (Sambucus spp.), blackberry (Rubus spp.) or common dogwood (Cornus sanguinea) were the most preferred species (D=0.01±0.71; -0.12±0.58; -0.2±0.78, respectively). Our results imply that biodiversity conservation, i.e. maintaining or establishing a multi-species understory layer, can be a good solution to reduce the additional negative game impact on native target tree species suffering from drought. Due to preference for Robinia pseudoacaciaselective browsing can decelerate the penetration of this species into native forest habitats. We have to consider the herbivorous pressure of ungulates and their feeding preferences in planning our future multifunctional forests in the light of climate change impacts

    Towards “Bionic” Proteins: Replacement of Continuous Sequences from HIF-1α with Proteomimetics to Create Functional p300 Binding HIF-1α Mimics

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    Using the HIF-1α transcription factor as a model, this manuscript illustrates how an extended sequence of α-amino acids in a polypeptide can be replaced with a non-natural topographical mimic of an α-helix comprised from an aromatic oligoamide. The resultant hybrid is capable of reproducing the molecular recognition profile of the p300 binding sequence of HIF-1α from which it is derived

    Glycan labeling strategies and their use in identification and quantification

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    Most methods for the analysis of oligosaccharides from biological sources require a glycan derivatization step: glycans may be derivatized to introduce a chromophore or fluorophore, facilitating detection after chromatographic or electrophoretic separation. Derivatization can also be applied to link charged or hydrophobic groups at the reducing end to enhance glycan separation and mass-spectrometric detection. Moreover, derivatization steps such as permethylation aim at stabilizing sialic acid residues, enhancing mass-spectrometric sensitivity, and supporting detailed structural characterization by (tandem) mass spectrometry. Finally, many glycan labels serve as a linker for oligosaccharide attachment to surfaces or carrier proteins, thereby allowing interaction studies with carbohydrate-binding proteins. In this review, various aspects of glycan labeling, separation, and detection strategies are discussed

    Lake sedimentary dna research on past terrestrial and aquatic biodiversity: Overview and recommendations

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    The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.</jats:p

    SiGe: A Promise into Reality?

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    The paper summarizes a few basic properties of SiGe showing that SiGe is an interesting material for high speed electronics. The advantage of using heterostructures in silicon-based technologies is demonstrated by taking SiGe heterobipolar transistors as an example. First results obtained with very fast and low-noise heterobipolar transistors are briefly mentioned. The paper is concluded by a short discussion of a few optoelectronic properties observed in various Si/Ge and Si/Si1x\text{}_{1-x}Gex\text{}_{x} strained-layer superlattices and quantum wells with particular emphasis on electroluminescence properties

    Mutagenicity of alkyl-([omega]-hydroxyalkyl) nitrosamines related to dibutylnitrosamine

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    Various alkyl-([omega]-hydroxyalkyl) derivatives related to dibutylnitrosamine (DBN) were investigated for mutagenicity in the absence of liver-activation system. Butyl-(4-hydroxybutyl)-, butyl-(3-hydroxypropyl)-, and butyl-(2-hydroxyethyl)-nitrosamines were so tested and found to be mutagenic for TA 1535 strain of Salmonella typhimurium. In all cases, a simple dose-response relationship was observed. Furthermore, no significant (p S. typhimurium by the higher dialkylnitrosamines is partially due to the formation of [omega]-hydroxylated derivatives in addition to the major mutagenic metabolite derived from [alpha]-carbon dealkylation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22725/1/0000280.pd

    Near infrared diffuse reflection and laser-induced fluorescence spectroscopy for myocardial tissue characterisation

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    In order to evaluate the potential of cardiovascular tissue characterisation using near-infrared (NIR) spectroscopy, spectra in a previously unexplored wavelength region 0.8-2.3 mu m were recorded from various pig heart tissue samples in vitro: normal myocardium (with and without endo/epicardium), aorta; fatty and fibrous heart tissue. The spectra were analysed with principal component analysis (PCA), revealing several spectroscopically characteristic features enabling tissue classification. Several of the identified spectral features could be attributed to specific tissue constituents by comparing the tissue signals with spectra obtained from water, elastin, collagen and cholesterol as well as with published data. The results obtained with the NIR spectroscopy technique in terms of its potential to classify different tissue types were compared with those from laser-induced fluorescence (LIF) using 337 nm excitation. LIF and NIR spectroscopy can in combination with PCA be used to discriminate between all previously mentioned tissue groups, apart from fatty versus fibrous tissue (LIF) and aorta versus fibrous tissue (NIR), respectively. The NIR analysis was improved by focusing the PCA to the wavelength segment 2.0-2.3 mu m, resulting in successful spectral characterisation of all cardiovascular tissue groups
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