307 research outputs found

    The adaptation of educational expectations in response to ability tracking: Variations by migration background

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    In various educational systems, students are sorted into separate secondary schools on the basis of their academic ability. Research suggests that this type of tracking impacts students' educational expectations, as expectations generally align with students' ability track. However, most research is cross-sectional and students with lower expectations are possibly also sorted into lower tracks. Moreover, the extent to which track placement influences expectations may vary across students. In this paper, we address the following research question: how does ability tracking impact the development of student expectations and how does this vary by students' migration background. Based on the literature on the immigrant aspiration–achievement paradox, we expect that students with a migration background are less likely to adapt expectations downwardly, and more likely to adapt expectations upward in response to track placement. Using German panel data, we examine the educational expectations of students with and without a migration background, before and after track placement. Moreover, we use variations in tracking procedures across German states to study how students who get tracked compare with students who do not get tracked in the development of their educational expectations. We show that students are more likely to upwardly adjust their expectations when their track placement exceeds their expectations and to downwardly adjust their expectations when their track placement is below their expectations. We find little support for the hypothesized variations by student migration background. Students whose parent(s) hold (a) Bachelor degree(s) are more likely to upwardly adjust their expectations when their track placement exceeds their expectations than students whose parent(s) maximally hold an upper secondary or vocational degree(s)

    Entwicklung von Phytophthora-resistentem Zuchtmaterial für den ökologischen Landbau

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    Insbesondere im ökologischen Kartoffelanbau stellt die Kraut- und Knollenfäule, hervorgerufen durch den Erreger Phytophthora infestans, ein großes Produktionsrisiko dar. Der Pflanzenzüchtung obliegt die Aufgabe Sorten bereit zu stellen, die sowohl durch überdurchschnittliche Toleranz als auch Resistenz gegenüber dieser Krankheit eine besonders gute Eignung zum Anbau haben. Über das Bundesprogramm „Ökologischer Landbau und andere Formen nachhaltiger Landwirtschaft“ (BÖLN) fördert das Bundesministerium für Ernährung und Landwirtschaft ein Verbundprojekt, in dem durch die Bündelung der deutschen Fachkompetenz dieser Aufgabenstellung züchterisch begegnet wird. Die Kooperationspartner entwickeln zusammen unter Inanspruchnahme einer breiten Pflanzendiversität, genetischer Ressourcen, moderner Selektionsmethoden und ökologischer Anbaumethoden Zuchtklone, die eine gut ausgeprägte Krautfäuleresistenz in Kombination mit weiteren Resistenz- und Qualitätseigenschaften besitzen. Dazu werden anhand von Ergebnissen eines Sortenversuchs Eltern für Kreuzungen ausgewählt, deren Nachkommen sowohl phänotypisch als auch durch genetische Marker hinsichtlich ihrer Resistenz bewertet werden

    Genetische Analyse der Feldresistenz von Kartoffeln gegenüber der Krautfäule im ökologischen Landbau

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    Late blight, caused by the oomycete Phytophthora infestans (Mont de Bary) poses one of the most important risks in production of organic potatoes. Favourable late blight conditions result in substantial losses in yield and quality in susceptible genotypes. In a series of field experiments between 2012 and 2015 at three organic sites in northern and southern Germany 148 cultivars assessed the outcome of decades of german late blight resistance breeding. The phenotyping of this diversity panel under natural conditions showed significant differences in the level of resistance within and across all maturity classes. These results were then used for a Single Nucleotide Polymorpism (SNP) assay on a 12k Infinion chip to locate QTLs for late blight resistance. Significant SNPs could be found for the traits late blight infection, maturity and maturity corrected late blight infection. These SNPs will be used for development of PCR markers for marker assisted selection in ongoing resistance breeding

    Kartoffelzüchtung für den ökologischen Landbau Wege in die Zukunft

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    Most crop varieties which are used in organic farming are developed for and under conventional farming techniques. These cultivars may then be tested and used for organic production. Between 2012 and 2018 the German Federal Ministry of Food and ew potato varieties under organic farming conditions. A great variety of modern cultivars is used to combine quality traits with the late blight resistance of pre-breeding clones from the Julius Kühn-Institute. To optimize results all breeding clones are grown and selected on organic farmland where they have to thrive under reduced nitrogen levels, mechanical weed reduction and high late blight pressure. Here we present results and practical experience from a participative approach where farmers are directly involved in the selection process

    Temperature Dependence of Steady-State and Presteady-State Kinetics of a Type IIb Na+/Pi Cotransporter

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    The temperature dependence of the transport kinetics of flounder Na+-coupled inorganic phosphate (Pi) cotransporters (NaPi-IIb) expressed in Xenopus oocytes was investigated using radiotracer and electrophysiological assays. 32Pi uptake was strongly temperature-dependent and decreased by ∼80% at a temperature change from 25°C to 5°C. The corresponding activation energy (E a) was ∼14 kcalmol−1 for the cotransport mode. The temperature dependence of the cotransport and leak modes was determined from electrogenic responses to 1 mM Pi and phosphonoformic acid (PFA), respectively, under voltage clamp. The magnitude of the Pi- and PFA-induced changes in holding current decreased with temperature. E a at −100 mV for the cotransport and leak modes was ∼16 kcalmol−1 and ∼11 kcalmol−1, respectively, which suggested that the leak is mediated by a carrier, rather than a channel, mechanism. Moreover, E a for cotransport was voltage-independent, suggesting that a major conformational change in the transport cycle is electroneutral. To identify partial reactions that confer temperature dependence, we acquired presteady-state currents at different temperatures with 0 mM Pi over a range of external Na+. The relaxation time constants increased, and the peak time constant shifted toward more positive potentials with decreasing temperature. Likewise, there was a depolarizing shift of the charge distribution, whereas the total available charge and apparent valency predicted from single Boltzmann fits were temperature-independent. These effects were explained by an increased temperature sensitivity of the Na+-debinding rate compared with the other voltage-dependent rate constant

    Impact of IL8 and IL8-Receptor alpha polymorphisms on the genetics of bronchial asthma and severe RSV infections

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    BACKGROUND: Interleukin 8 (IL8) belongs to the family of chemokines. It mediates the activation and migration of neutrophils from peripheral blood into tissue and hereby plays a pivotal role in the initiation of inflammation. Thus it is important in inflammatory lung diseases like bronchial asthma or severe infections by Respiratory Syncytial Virus (RSV). IL8 acts through binding to the IL8-Receptor alpha (IL8RA). For both genes association with asthma has been described. In addition, IL8 has been found in association with RSV bronchiolitis. The aim of our study was to test both genes for association with asthma and severe RSV infections. In addition we were interested in whether a common genetic background of both diseases exists in regards to these genes. METHODS: We genotyped the two IL8 promotor polymorphisms -251A/T and -781C/T and the three amino acid variants M31R, S276T and R335C in IL8RA on 322 children with asthma, 131 infants with severe RSV associated diseases and 270 controls. Statistical analyses made use of the Armitage's trend test for single polymorphisms and FAMHAP for calculations of haplotypes. RESULTS: We found association of the IL8 polymorphism -781C/T as well as IL8 haplotypes with asthma (p = 0.011 and p = 0.036, respectively). In addition, direct comparison of the asthmatic population with the RSV population revealed significant differences, both for -781C/T alone (p = 0.034) and IL8 haplotypes (p = 0.005). The amino acid variants in IL8RA were evenly distributed in between all three populations. CONCLUSION: We conclude from our data that IL8 might play a role in the genetic predisposition to asthma and that these effects are different or even opposite to the effects on severe RSV diseases. Furthermore, IL8RA is unlikely to play a major role in the genetics of either disease

    Immunohistochemical localization and quantitative assessment of GnRH-, FSH-, and LH-receptor mRNA Expression in canine skin: a powerful tool to study the pathogenesis of side effects after spaying

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    It has been proposed that gonadotropins and/or gonadotropin releasing hormone (GnRH) could be involved in the pathophysiology of the side effects after spaying in bitches, such as urinary incontinence and an increased production of a woolly undercoat. In order to provide tools to investigate the role of these hormones in dogs we developed immunohistochemical techniques and real-time RT-PCR to study whether GnRH-, LH-, and FSH-receptors exist in canine skin and urinary bladder. Tissue samples from the skin of the flank region and the ventral midline of the urinary bladder from euthanised dogs were examined. We were able to quantify mRNA expression of GnRH-, FSH-, and LH-receptors in canine skin and bladder biopsies with a high primer efficacy. Immunohistochemical studies showed that GnRH-, FSH-, and LH-receptors are expressed in vessel walls, the epidermis, the hair follicle and in sebaceous and sweat glands in canine skin and in transitional epithelium, and smooth muscle tissue in the urinary bladder. Our data provide the fundamentals to examine the distribution of FSH-, LH-, and GnRH-receptors in canine skin and urinary bladder and to assess gene activity at the transcriptional level by real-time RT-PC

    Dynamic correlation functions and Boltzmann Langevin approach for driven one dimensional lattice gas

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    We study the dynamics of the totally asymmetric exclusion process with open boundaries by phenomenological theories complemented by extensive Monte-Carlo simulations. Upon combining domain wall theory with a kinetic approach known as Boltzmann-Langevin theory we are able to give a complete qualitative picture of the dynamics in the low and high density regime and at the corresponding phase boundary. At the coexistence line between high and low density phases we observe a time scale separation between local density fluctuations and collective domain wall motion, which are well accounted for by the Boltzmann-Langevin and domain wall theory, respectively. We present Monte-Carlo data for the correlation functions and power spectra in the full parameter range of the model.Comment: 10 pages, 9 figure

    Sites of Failure in Breast Cancer Patients with Extracapsular Invasion of Axillary Lymph Node Metastases: No Need for Axillary Irradiation?!

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    Background and Purpose:: Extracapsular spread (ECS) is frequent, but the specific sites of relapse are seldom given in the literature. In this study it was evaluated, if ECS might be an indicator for axillary irradiation. Patients and Methods:: After a retrospective review of pathology reports, the information about ECS was available in 254 lymph node-positive patients: ECS was absent in 34% (ECS-negative; n = 87) and present in 66% (ECS-positive; n = 167). All patients were irradiated locally, 78 patients got periclavicular and 74 axillary irradiation (median total dose: 50.4 Gy). 240/254 patients (94.5%) received systemic treatment/s. Mean follow-up was 46 months. Results:: The regional relapse rate was 4.6% without ECS versus 9.6% with ECS. The 5-year axillary relapse-free survival was 100% in ECS-negative and 90% in ECS-positive patients (p = 0.01), whereas corresponding values for periclavicular relapse-free survival (with ECS: 91% ± 4%; without ECS: 94% ± 3%; p = 0.77) and local relapse-free survival (with ECS: 86% ± 4%; without ECS: 91% ± 3%; p = 0.69) were not significantly different. χ2-tests revealed a high correlation of ECS with T-stage, number of positive lymph nodes and progesterone receptor status, comparisons with estrogen receptor, grade, or age were not significant. In multivariate analysis number of positive lymph nodes was solely significant for regional failure. Dividing the patients into those with one to three and those with four or more positive lymph nodes, ECS lost its significance for axillary failure. Conclusion:: ECS was accompanied by an enhanced axillary failure rate in univariate analysis, which was no longer true after adjusting for the number of positive lymph node
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