144 research outputs found

    Cover Crops and Fertilization Alter Nitrogen Loss in Organic and Conventional Conservation Agriculture Systems

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    Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH3 volatilization, N2O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic system with a hairy vetch cover crop employing three fertilization schemes (o N, organic N, or a fertilizer N-credit approach); and (3) a conventional system with a winter wheat cover crop and three fertilization schemes (o N, urea N, or organic N). In the unfertilized organic system, cover crop species affected NO3-N leaching (vetch \u3e bi-culture \u3e wheat) and N2O-N emissions and yield during corn growth (vetch, bi-culture \u3e wheat). Fertilization increased soil inorganic N, gaseous N loss, N leaching, and yield in the organic vetch and conventional wheat systems. Fertilizer scheme affected the magnitude of growing season N2O-N loss in the organic vetch system (organic N \u3e fertilizer N-credit) and the timing of loss (organic N delayed N2O-N loss vs. urea) and NO3-N leaching (urea \u3e\u3e organic N) in the conventional wheat system, but had no effect on yield. Cover crop selection and N fertilization techniques can reduce N leaching and greenhouse gas emissions without sacrificing yield, thereby enhancing N conservation in both organic and conventional conservation agriculture systems

    Epithelial cell-directed efferocytosis in the post-partum mammary gland is necessary for tissue homeostasis and future lactation

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    <p>Abstract</p> <p>Background</p> <p>Mammary glands harbor a profound burden of apoptotic cells (ACs) during post-lactational involution, but little is known regarding mechanisms by which ACs are cleared from the mammary gland, or consequences if this process is interrupted. We investigated AC clearance, also termed efferocytosis, during post-lactational remodeling, using mice deficient for MerTK, Axl, and Tyro3, three related receptor tyrosine kinases (RTKs) regulating macrophage-mediated efferocytosis in monocytes. MerTK expression, apoptosis and the accumulation of apoptotic debris were examined in histological sections of MerTK-deficient, Axl/Tyro3-deficient, and wild-type mammary glands harvested at specific time points during lactation and synchronized involution. The ability of primary mammary epithelial cells (MECs) to engulf ACs was assessed in culture. Transplant of MerTK-deficient mammary epithelium into cleared WT mammary fat pads was used to assess the contribution of WT mammary macrophages to post-lactational efferocytosis.</p> <p>Results</p> <p>ACs induced MerTK expression in MECs, resulting in elevated MerTK levels at the earliest stages of involution. Loss of MerTK resulted in AC accumulation in post-lactational MerTK-deficient mammary glands, but not in Axl and Tyro3-deficient mammary glands. Increased vascularization, fibrosis, and epithelial hyperproliferation were observed in MerTK-deficient mammary glands through at least 60 days post-weaning, due to failed efferocytosis after lactation, but did not manifest in nulliparous mice. WT host-derived macrophages failed to rescue efferocytosis in transplanted MerTK-deficient mammary epithelium.</p> <p>Conclusion</p> <p>Efferocytosis by MECs through MerTK is crucial for mammary gland homeostasis and function during the post-lactational period. Efferocytosis by MECs thus limits pathologic consequences associated with the apoptotic load following lactation.</p

    Depression and anxiety symptoms of british adoptive parents: a prospective four-wave longitudinal study

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    The mental health of birth parents has gained attention due to the serious negative consequences for personal, family, and child outcomes, but depression and anxiety in adoptive parents remains under-recognized. Using a prospective, longitudinal design, we investigated anxiety and depression symptoms in 96 British adoptive parents over four time points in the first four years of an adoptive placement. Depression and anxiety symptom scores were relatively stable across time. Growth curve analysis showed that higher child internalizing scores and lower parental sense of competency at five months post-placement were associated with higher initial levels of parental depressive symptoms. Lower parental sense of competency was also associated with higher initial levels of parental anxiety symptoms. Parents of older children and those with higher levels of parental anxiety and sense of competency at five months post-placement had a steeper decrease in depressive symptoms over time. Support for adoptive families primarily focuses on child adjustment. Our findings suggest that professional awareness of parental mental health post-placement may be necessary, and interventions aimed at improving parents’ sense of competency may be beneficial

    Adverse childhood experiences of children adopted from care: The importance of adoptive parental warmth for future child adjustment

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    We investigated the relationship between adverse childhood experiences (ACEs) and children’s internalising symptoms and externalising problems in the Wales Adoption Cohort Study, a prospective longitudinal study that used case file records (n = 374) for a sample of British children adopted from care (M = 2 years, 55% male). Parents (n = 96) completed questionnaires at 3–5 months, 15–17 months, and 31–33 months post-placement. We hypothesised that: (1) children adopted from care would have experienced more ACEs than children in the general population; (2) the number of ACEs would be associated with higher internalising symptom and externalising problem scores; and (3) adoptive parental warmth would moderate the relationship between ACEs and post-placement internalising symptoms and externalising problems. Nearly half (42%) of the children experienced four or more ACEs. Internalising symptoms and externalising problems were significantly higher than the UK general population. The number of ACEs was associated with internalising symptoms 3 years post-adoptive placement but this relationship was moderated by adoptive parental warmth. This study profiles the experiences and characteristics of a national sample of adopted children and highlights the potential importance of parent warmth as a factor that ameliorates the impact of ACEs on poor child outcomes

    An Examination of the Changes in Science Teaching Orientations and Technology-Enhanced Tools for Student Learning in the Context of Professional Development

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    This research examines how science teaching orientations and beliefs about technology-enhanced tools change over time in professional development (PD). The primary data sources for this study came from learning journals of 8 eighth grade science teachers at the beginning and conclusion of a year of PD. Based on the analysis completed, Information Transmission (IT) and Struggling with Standards-Based Reform (SSBR) profiles were found at the beginning of the PD, while SSBR and Standards-Based Reform (SBR) profiles were identified at the conclusion of PD. All profiles exhibited Vision I beliefs about the goals and purposes for science education, while only the SBR profile exhibited Vision II goals and purposes for science teaching. The IT profile demonstrated naïve or unrevealed beliefs about the nature of science, while the SSBR and SBR profiles had more sophisticated beliefs in this area. The IT profile was grounded in more teacher-centered beliefs about science teaching and learning as the other two profiles revealed more student-centered beliefs. While no beliefs about technology-enhanced tools were found for the IT profile, these were found for the other two profiles. Our findings suggest promising implications for (a) Roberts\u27 Vision II as a central support for reform efforts, (b) situating technology-enhanced tools within the beliefs about science teaching and learning dimension of science teaching orientations, and (c) revealing how teacher orientations develop as a result of PD

    ErbB4/HER4: Role in Mammary Gland Development, Differentiation and Growth Inhibition

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    The ErbB receptor tyrosine kinase family has often been associated with increased growth of breast epithelial cells, as well as malignant transformation and progression. In contrast, ErbB4/HER4 exhibits unique attributes from a two step proteolytic cleavage which releases an 80 kilodalton, nuclear localizing, tyrosine kinase to a signal transduction mechanism that slows growth and stimulates differentiation of breast cells. This review provides an overview of ErbB4/HER4 in growth and differentiation of the mammary epithelium, including its physiologic role in development, the contrasting growth inhibition/tumor suppression and growth acceleration of distinct ErbB4/HER4 isoforms and a description of the unique cell cycle regulated pattern of nuclear HER4 ubiquitination and destruction

    Dietary yeast influences ethanol sedation in Drosophila via serotonergic neuron function

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    Abuse of alcohol is a major clinical problem with far- reaching health consequences. Understanding the environmental and genetic factors that contribute to alcohol- related behaviors is a potential gateway for developing novel therapeutic approaches for patients that abuse the drug. To this end, we have used Drosophila melanogaster as a model to investigate the effect of diet, an environmental factor, on ethanol sedation. Providing flies with diets high in yeast, a routinely used component of fly media, increased their resistance to ethanol sedation. The yeast- induced resistance to ethanol sedation occurred in several different genetic backgrounds, was observed in males and females, was elicited by yeast from different sources, was readily reversible, and was associated with increased nutrient intake as well as decreased internal ethanol levels. Inhibition of serotonergic neuron function using multiple independent genetic manipulations blocked the effect of yeast supplementation on ethanol sedation, nutrient intake, and internal ethanol levels. Our results demonstrate that yeast is a critical dietary component that influences ethanol sedation in flies and that serotonergic signaling is required for the effect of dietary yeast on nutrient intake, ethanol uptake/elimination, and ethanol sedation. Our studies establish the fly as a model for diet- induced changes in ethanol sedation and raise the possibility that serotonin might mediate the effect of diet on alcohol- related behavior in other species.Flies fed a high yeast diet consume more nutrients, have decreased levels of internal ethanol when exposed to ethanol vapor and require longer exposure to ethanol to become sedated (ie, increased ST50). Our studies implicate serotonergic neurons as key regulators of nutrient consumption and therefore, the effect of dietary yeast on ethanol sedation in flies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155987/1/adb12779.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155987/2/adb12779_am.pd

    MADNESS: A Multiresolution, Adaptive Numerical Environment for Scientific Simulation

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    MADNESS (multiresolution adaptive numerical environment for scientific simulation) is a high-level software environment for solving integral and differential equations in many dimensions that uses adaptive and fast harmonic analysis methods with guaranteed precision based on multiresolution analysis and separated representations. Underpinning the numerical capabilities is a powerful petascale parallel programming environment that aims to increase both programmer productivity and code scalability. This paper describes the features and capabilities of MADNESS and briefly discusses some current applications in chemistry and several areas of physics

    HER4 D-Box Sequences Regulate Mitotic Progression and Degradation of the Nuclear HER4 Cleavage Product s80HER4

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    Heregulin-mediated activation of HER4 initiates receptor cleavage (releasing an 80-kDa HER4 intracellular domain, s80HER4, containing nuclear localization sequences) and results in G2/M delay by unknown signaling mechanisms. We report herein that s80HER4 contains a functional cyclin B-like sequence known as a D-box, which targets proteins for degradation by APC/C, a multisubunit ubiquitin ligase. s80HER4 ubiquitination and ptoteosomal degradation occurred during mitosis but not during S-phase. Inhibition of an APC subunit (APC2) using siRNA knock-down impaired s80HER4 degradation. Mutation of the s80HER4 D-box sequence stabilized s80HER4 during mitosis, and s80HER4-dependent growth inhibition via G2/M delay was significantly greater with the D-box mutant. Polyomvirus middle-T antigen-transformed HC11 cells expressing s80HER4 resulted in smaller, less proliferative, more differentiated tumors in vivo than those expressing kinase-dead s80HER4 or the empty vector. Cells expressing s80HER4 with a disrupted D-box did not form tumors, instead forming differentiated ductal structures. These results suggest that cell cycle-dependent degradation of s80HER4 limits its growth inhibitory action, and stabilization of s80HER4 enhances tumor suppression, thus providing a link between HER4-mediated growth inhibition and cell cycle control

    MerTK inhibition in tumor leukocytes decreases tumor growth and metastasis

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    MerTK, a receptor tyrosine kinase (RTK) of the TYRO3/AXL/MerTK family, is expressed in myeloid lineage cells in which it acts to suppress proinflammatory cytokines following ingestion of apoptotic material. Using syngeneic mouse models of breast cancer, melanoma, and colon cancer, we found that tumors grew slowly and were poorly metastatic in MerTK–/– mice. Transplantation of MerTK–/– bone marrow, but not wild-type bone marrow, into lethally irradiated MMTV-PyVmT mice (a model of metastatic breast cancer) decreased tumor growth and altered cytokine production by tumor CD11b+ cells. Although MerTK expression was not required for tumor infiltration by leukocytes, MerTK–/– leukocytes exhibited lower tumor cell–induced expression of wound healing cytokines, e.g., IL-10 and growth arrest-specific 6 (GAS6), and enhanced expression of acute inflammatory cytokines, e.g., IL-12 and IL-6. Intratumoral CD8+ T lymphocyte numbers were higher and lymphocyte proliferation was increased in tumor-bearing MerTK–/– mice compared with tumor-bearing wild-type mice. Antibody-mediated CD8+ T lymphocyte depletion restored tumor growth in MerTK–/– mice. These data demonstrate that MerTK signaling in tumor-associated CD11b+ leukocytes promotes tumor growth by dampening acute inflammatory cytokines while inducing wound healing cytokines. These results suggest that inhibition of MerTK in the tumor microenvironment may have clinical benefit, stimulating antitumor immune responses or enhancing immunotherapeutic strategies
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