TY  - JOUR
A1  - Wiesmeier, Martin
A1  - Munro, Sam
A1  - Barthold, Frauke Katrin
A1  - Steffens, Markus
A1  - Schad, Peter
A1  - Kögel-Knabner, Ingrid
T1  - Carbon storage capacity of semi-arid grassland soils and sequestration potentials in northern China
JF  - Global change biology
N2  - Organic carbon (OC) sequestration in degraded semi-arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi-arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles <20m, OC sequestration potentials of degraded steppe soils (grazing land, arable land, eroded areas) were estimated. The analysis of natural grassland soils revealed a strong linear regression between the proportion of the fine fraction and its OC content, confirming the importance of silt and clay particles for OC stabilization in steppe soils. This relationship was similar to derived regressions in temperate and tropical soils but on a lower level, probably due to a lower C input and different clay mineralogy. In relation to the estimated OC storage capacity, degraded steppe soils showed a high OC saturation of 78-85% despite massive SOC losses due to unsustainable land use. As a result, the potential of degraded grassland soils to sequester additional OC was generally low. This can be related to a relatively high contribution of labile SOC, which is preferentially lost in the course of soil degradation. Moreover, wind erosion leads to substantial loss of silt and clay particles and consequently results in a direct loss of the ability to stabilize additional OC. Our findings indicate that the SOC loss in semi-arid environments induced by intensive land use is largely irreversible. Observed SOC increases after improved land management mainly result in an accumulation of labile SOC prone to land use/climate changes and therefore cannot be regarded as contribution to long-term OC sequestration.
KW  - climate change
KW  - fine fraction
KW  - soil organic carbon
KW  - soil texture
KW  - steppe soils
Y1  - 2015
U6  - https://doi.org/10.1111/gcb.12957
SN  - 1354-1013
SN  - 1365-2486
VL  - 21
IS  - 10
SP  - 3836
EP  - 3845
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Günther, Oliver
A1  - Mangelsdorf, Birgit
A1  - Mitzner, Rolf
A1  - Loschelder, Wolfgang
A1  - Peter, Andreas
A1  - Eckert, Barbara
A1  - Mikelskis, Helmut
A1  - Klein, Alfred
A1  - Kirsch, Bärbel
A1  - Edelstein, Wolfgang
A1  - Thomas, Grünewald
A1  - Thomas, Pösl
A1  - Wagner, Dieter
A1  - Winskowski, Friedrich
A1  - Schad, Martina
A1  - Frey, Anne
A1  - Bickenbach, Wulf
A1  - Madani, Roya
A1  - Olaka, Lydia
T1  - Portal alumni
T2  - Das Ehemaligen-Magazin der Universität Potsdam
N2  - Das zurückliegende Jahr stand an der Universität Potsdam auch im Zeichen des zwanzigjährigen Jubiläums der Hochschule. Am 15. Juli 1991, wurde sie gegründet und während einer Festwoche feierten Professorinnen und Professoren, Mitarbeiterinnen, Mitarbeiter und Studierende dieses Jubiläum gebührend. Seit der Gründung der größten brandenburgischen Hochschule sind wissenschaftliches Renommee, Ansehen und Attraktivität stetig gewachsen. Gerade in den letzten Jahren hat sie ihr Profil geschärft. Vor allem die Kognitions-, die Geo- und Biowissenschaften sind hier zu nennen. Aber auch die Lehrerbildung besitzt einen hohen Stellenwert. International anerkannte Forschungsbereiche, Wissenschaftspreise, eine erfolgreiche Drittmittelbilanz und nicht zuletzt die bauliche Entwicklung an allen drei Standorten sind sichtbare Indikatoren für die erfolgreiche Entwicklung, die die Universität Potsdam in den letzten zwei Jahrzehnten durchlaufen hat. Die drei ehemaligen Präsidenten sowie verschiedene andere Protagonisten werfen in dieser Ausgabe der Portal Alumni einen Blick auf unterschiedliche Aspekte der zurückliegenden Entwicklung der Universität. Vom Erfolg der Universität zeugt auch die wachsende Zahl der Absolventinnen und Absolventen, die die Universität verlassen. Portal Alumni stellt in der vorliegenden Ausgabe deshalb Absolventen und deren universitäre und berufliche Lebenswege genauer vor und lässt damit zugleich kaleidoskopartig 20 Jahre Studium an der Universität Potsdam Revue passieren.
T3  - Portal alumni : das Ehemaligen-Magazin der Universität Potsdam - 9/2012 
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-444943
SN  - 1613-2343
IS  - 9
ER  - 
TY  - JOUR
A1  - Sebold, Miriam
A1  - Nebe, Stephan
A1  - Garbusow, Maria
A1  - Guggenmos, Matthias
A1  - Schad, Daniel
A1  - Beck, Anne
A1  - Kuitunen-Paul, Sören
A1  - Sommer, Christian
A1  - Frank, Robin
A1  - Neu, Peter
A1  - Zimmermann, Ulrich S.
A1  - Rapp, Michael A.
A1  - Smolka, Michael N.
A1  - Huys, Quentin J. M.
A1  - Schlagenhauf, Florian
A1  - Heinz, Andreas
T1  - When Habits Are Dangerous: Alcohol Expectancies and Habitual Decision Making Predict Relapse in Alcohol Dependence
JF  - Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry
N2  - BACKGROUND: Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS: Ninety detoxified, medication-free, alcohol-dependent patients and 96 age-and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS: Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS: These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies.
KW  - Alcohol dependence
KW  - Alcohol expectancy
KW  - Goal-directed control
KW  - Medial prefrontal cortex
KW  - Reinforcement learning
KW  - Treatment outcome
Y1  - 2017
U6  - https://doi.org/10.1016/j.biopsych.2017.04.019
SN  - 0006-3223
SN  - 1873-2402
VL  - 82
SP  - 847
EP  - 856
PB  - Elsevier
CY  - New York
ER  -