1,038 research outputs found

    The impact of long-term elevated CO2 on C and N retention in stable SOM pools

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    Elevated atmospheric CO2 frequently increases plant production and concomitant soil C inputs, which may cause additional soil C sequestration. However, whether the increase in plant production and additional soil C sequestration under elevated CO2 can be sustained in the long-term is unclear. One approach to study C-N interactions under elevated CO2 is provided by a theoretical framework that centers on the concept of progressive nitrogen limitation (PNL). The PNL concept hinges on the idea that N becomes less available with time under elevated CO2. One possible mechanism underlying this reduction in N availability is that N is retained in long-lived soil organic matter (SOM), thereby limiting plant production and the potential for soil C sequestration. The long-term nature of the PNL concept necessitates the testing of mechanisms in field experiments exposed to elevated CO2 over long periods of time. The impact of elevated CO2 and N-15 fertilization on L. perenne and T. repens monocultures has been studied in the Swiss FACE experiment for ten consecutive years. We applied a biological fractionation technique using long-term incubations with repetitive leaching to determine how elevated CO2 affects the accumulation of N and C into more stable SOM pools. Elevated CO2 significantly stimulated retention of fertilizer-N in the stable pools of the soils covered with L. perenne receiving low and high N fertilization rates by 18 and 22%, respectively, and by 45% in the soils covered by T. repens receiving the low N fertilization rate. However, elevated CO2 did not significantly increase stable soil C formation. The increase in N retention under elevated CO2 provides direct evidence that elevated CO2 increases stable N formation as proposed by the PNL concept. In the Swiss FACE experiment, however, plant production increased under elevated CO2, indicating that the additional N supply through fertilization prohibited PNL for plant production at this site. Therefore, it remains unresolved why elevated CO2 did not increase labile and stable C accumulation in these systems

    Modeling and analysis of the dynamic behavior of the XlnR regulon in Aspergillus niger

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    Background: In this paper the dynamics of the transcription-translation system for XlnR regulon in Aspergillus niger is modeled. The model is based on Hill regulation functions and uses ordinary differential equations. The network response to a trigger of D-xylose is considered and stability analysis is performed. The activating, repressive feedback, and the combined effect of the two feedbacks on the network behavior are analyzed. Results: Simulation and systems analysis showed significant influence of activating and repressing feedback on metabolite expression profiles. The dynamics of the D-xylose input function has an important effect on the profiles of the individual metabolite concentrations. Variation of the time delay in the feedback loop has no significant effect on the pattern of the response. The stability and existence of oscillatory behavior depends on which proteins are involved in the feedback loop. Conclusions: The dynamics in the regulation properties of the network are dictated mainly by the transcription and translation degradation rate parameters, and by the D-xylose consumption profile. This holds true with and without feedback in the network. Feedback was found to significantly influence the expression dynamics of genes and proteins. Feedback increases the metabolite abundance, changes the steady state values, alters the time trajectories and affects the response oscillatory behavior and stability conditions. The modeling approach provides insight into network behavioral dynamics particularly for small-sized networks. The analysis of the network dynamics has provided useful information for experimental design for future in vitro experimental wor

    Structure of trans-bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-N1,N'[diaqua- manganese(II) dibromide

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    [Mn(C12H10N6)2(H2O)2]Br2, Mr = 727.28, orthorhombic, Pbca, a = 10.734 (6), b = 17.084 (0), c = 15.182 (6) angstrom, V = 2784 angstrom 3, Z = 4, D(x) = 1.734 g cm-3, lambda-(Mo K-alpha) = 0.71073 angstrom, mu = 33.23 cm-1, F(000) = 1450, T = 295 K, final R = 0.032 for 1493 reflections [I > 2-sigma(I)]. The title compound is the first reported mononuclear compound with the ligand 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole. The manganese ions, situated on an inversion centre, are coordinated by four nitrogen atoms with an N-Mn-N angle of 74.1 (1)-degrees and Mn-N distances of 2.188 (4) and 2.266 (4) angstrom. Two axial water molecules [Mn-O = 2.200 (4) angstrom] complete the coordination sphere of the metal, which is pseudo-octahedral. The two bromide ions are not coordinated but are involved in an extended hydrogen-bridging network with the water ligands and the amino group of the triazole

    The role of client empathy in treatment outcome in a sample of adolescents referred to forensic youth psychiatric services

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    Starting from the assumption that empathy is crucial in the therapeutic process, the current study explored whether client empathy before treatment relates to treatment outcome, whether client empathy is subject to change in the first six months of treatment, whether such change relates to treatment outcome and whether therapist factors relate to possible changes in client empathy. In total 90 adolescents treated by 31 therapists at forensic psychiatric services participated in the study. Client empathy was assessed with self-report questionnaires of affective and cognitive empathy at intake and again at six months of treatment. Therapeutic change was rated by their therapist. Client empathy before treatment was not systematically related to treatment outcome. Cognitive empathy tended to improve during treatment, stronger in girls than boys, and depending in part on the therapist's gender: Under conditions of a male (not female) therapist boys reported less improvement in cognitive empathy than girls. The most consistent study result was that improvement in cognitive empathy contributed positively to treatment outcome. The study provides new data on the role of client empathy in the treatment of forensic youth psychiatric patients. If replicated, these findings have important implications for treatment and training in juvenile forensic psychiatry

    The relation between self-event connections and personality functioning in youth with severe psychopathology

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    OBJECTIVE: One way in which individuals construct their narrative identity is by making self‐event connections, which are often linked to better functioning. Being unable to make connections is related to identity discontinuity and psychopathology. Work in the general population corroborates this association, but also highlights the importance of focusing on specific aspects of these connections and on vulnerable populations. METHOD: We examined the association of self‐event connections with personality functioning in youth with severe psychopathology (cross‐sectional N = 228, M (age) = 19.5, longitudinal N = 84), and the role of event and connection valence in the subsample of youth who made a connection (n = 188 and n = 68). Negative affectivity was controlled for in all models. RESULTS: We found no evidence that self‐event connections, nor connection valence and its interaction with event valence, are related to functioning. Positive event valence was associated with better functioning. Higher negative affectivity was strongly linked to lower functioning and explained the relation between event valence and functioning. No longitudinal associations emerged. CONCLUSIONS: These findings show that for youth with severe psychopathology making self‐event connections may not be associated with better functioning. Moreover, negative affectivity may be a distal predictor of both event valence and functioning

    Diermeel in diervoeders? : een methodische discussie met stakeholders

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    In dit rapport wordt verslag gedaan van een workshop die ten doel had een beter inzicht te krijgen in de belangen van de Nederlandse samenleving met betrekking tot de vraag of het beleid ten aanzien van dierlijke eiwitten in diervoeders versoepeld kan worden. Daarbij is gebruik maakt van een nieuwe, brede afwegingsmethodiek (TRAK) waarmee het mogelijk is verschillende beleidsscenario's' aan de hand van verschillende waarden te beoordelen en te scoren

    Lewensloop van 'n Kaapse buffelbevolking <I>Syncerus caffer</I> in die Bontebok Nasionale Park

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    The course of an experiment to re-introduce the Cape buffalo Syncerus coffer in the Bontebok National Park, near Swellendam, is described and illustrated

    Гарантоздатність як фундаментальний узагальнюючий та інтегруючий підхід

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    Представлені головні принципи та умови становлення і етапи розвитку фундаментальної теорії і практики узагальнюючих та інтегруючих концепцій гарантоздатності, починаючи з першої об’єднаної конференції двох наукових шкіл Дж. фон Неймана і Н. Вінера. Приведені основні положення розвитку теоретичних засад і результатів прикладних досліджень інтеграційних процесів безвідмовності (надійності), відмовостійкості та гарантоздатності інформаційно-управляючих комп’ютерних систем (ІУКС).Представлены главные принципы, условия становления и этапы развития фундаментальной теории и практики обобщающих и интегрирующих концепций гарантоспособности, начиная с первой объединённой конференции двух научных школ Дж. фон Неймана и Н. Винера. Приведены основные положения развития теоретических основ и результатов прикладных исследований интеграционных процессов безотказности (надёжности), отказоустойчивости и гарантоспособности информационно-управляющих компьютерных систем (ИУКС).The main principles and conditions of formation and stages of development of the fundamental theory and practice of the generalizing and integrating concepts of dependability were presented after the leadthrough the first joint conference of two scientific schools of J. von Neumann and N. Wiener. The basic aspects of development of theoretical principles and results of applied researches of integration processes of reliability (fail-safety)
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