Impact of 40 years poplar cultivation on soil carbon stocks and greenhouse gas fluxes

International audienceWithin the JRC Kyoto Experiment in the Regional Park and UN-Biosphere Reserve "Parco Ticino" (North-Italy, near Pavia), the soil carbon stocks and fluxes of CO2, N2O, and CH4 were measured in a poplar plantation in comparison with a natural mesohygrophilous deciduous forest nearby, which represents the pristine land cover of the area. Soil fluxes were measured using the static and dynamic closed chamber techniques for CH4 N2O, and CO2, respectively. We made further a pedological study to relate the spatial variability found with soil parameters. Annual emission fluxes of N2O and CO2 and deposition fluxes of CH4 were calculated for the year 2003 for the poplar plantation and compared to those measured at the natural forest site. N2O emissions at the poplar plantation were 0.15$plusmn;0.1 g N2O m-2 y-1 and the difference to the emissions at the natural forest of 0.07±0.06 g N2O m-2 y-1 are partly due to a period of high emissions after the flooding of the site at the end of 2002. CH4 consumption at the natural forest was twice as large as at the poplar plantation. In comparison to the relict forest, carbon stocks in the soil under the poplar plantation were depleted by 61% of surface (10 cm) carbon and by 25% down the profile under tillage (45 cm). Soil respiration rates were not significant different at both sites with 1608±1053 and 2200±791 g CO2 m-2 y-1 at the poplar plantation and natural forest, respectively, indicating that soil organic carbon is much more stable in the natural forest. In terms of the greenhouse gas budget, the non-CO2 gases contributed minor to the overall soil balance with only 0.9% (N2O) and -0.3% (CH4 of CO2-eq emissions in the natural forest, and 2.7% (N2O) and -0.2% of CO2-eq. emissions in the poplar plantation. The very high spatial variability of soil fluxes within the two sites was related to the morphology of the floodplain area, which was formed by the historic course of the Ticino river and led to a small-scale (tenth of meters) variability in soil texture and to small-scale differences in elevation. Differences of site conditions are reflected by differences of inundation patterns, ecosystem productivity, CO2 and N2O emission rates, and soil contents of carbon and nitrogen. Additional variability was observed during a flooding event and after fertilisation at the poplar site. Despite of this variability, the two sites are comparable as both originate from alluvial deposits. The study shows that changes in soil carbon stocks and related fertility are the most visible phenomena after 40 years of land use change from a pristine forest to a fast growing poplar plantation. Therefore, the conservation and careful management of existing carbon stocks deserves highest priority in the context of the Kyoto Protocol

Urban agriculture: a global analysis of the space constraint to meet urban vegetable demand

Urban agriculture (UA) has been drawing a lot of attention recently for several reasons: the majority of the world population has shifted from living in rural to urban areas; the environmental impact of agriculture is a matter of rising concern; and food insecurity, especially the accessibility of food, remains a major challenge. UA has often been proposed as a solution to some of these issues, for example by producing food in places where population density is highest, reducing transportation costs, connecting people directly to food systems and using urban areas efficiently. However, to date no study has examined how much food could actually be produced in urban areas at the global scale. Here we use a simple approach, based on different global-scale datasets, to assess to what extent UA is constrained by the existing amount of urban space. Our results suggest that UA would require roughly one third of the total global urban area to meet the global vegetable consumption of urban dwellers. This estimate does not consider how much urban area may actually be suitable and available for UA, which likely varies substantially around the world and according to the type of UA performed. Further, this global average value masks variations of more than two orders of magnitude among individual countries. The variations in the space required across countries derive mostly from variations in urban population density, and much less from variations in yields or per capita consumption. Overall, the space required is regrettably the highest where UA is most needed, i.e., in more food insecure countries. We also show that smaller urban clusters (i.e., <100 km2 each) together represent about two thirds of the global urban extent; thus UA discourse and policies should not focus on large cities exclusively, but should also target smaller urban areas that offer the greatest potential in terms of physical space

The PinK Study - Methodology of the Baseline Survey of a Prospective Cohort Study of Couples Undergoing Fertility Treatment

Der Methodenbericht beschreibt die Basiserhebung der PinK-Studie "Paare in Kinderwunschbehandlung". Ziel der Studie ist ein besseres Verständnis der Situation von Paaren mit unerfülltem Kinderwunsch und umfassende Erkenntnisse über die Wege in die Kinderwunschbehandlung. Der Ansatz der Studie ist interdisziplinär. Sie ist als prospektive Kohortenstudie in einem klinischen Umfeld angelegt. Zielgruppe der Studie sind Paare mit unerfülltem Kinderwunsch, die zwischen Juli 2012 und Mai 2013 ein Kinderwunschzentrum in Rheinland-Pfalz oder in der hessischen Landeshauptstadt aufgesucht haben. Als Erhebungsinstrument kamen schriftliche Fragebögen zum Einsatz, die den Patienten durch das Personal der Kinderwunschzentren übergeben wurden. Der finale Datensatz enthält alle bis Ende Juli 2013 zurückgesendete Fragebögen. Es haben 323 Frauen und 242 Männer an der Befragung teilgenommen, darunter 234 Paare, für die vollständige Informationen zu beiden Partnern vorliegen. Der Datensatz ermöglicht damit neben Geschlechtervergleichen auch Paaranalysen. Die Gesamtrücklaufquote liegt bei 31% mit teilweise erheblichen Unterschieden zwischen den Kliniken - mögliche Ursachen und Folgen werden diskutiert. Die Studienpopulation wird hinsichtlich zentraler soziodemografischer Merkmale beschrieben.This paper describes the realization of the baseline survey of the study ‘PinK- Paare in Kinderwunschbehandlung’ (couples undergoing fertility treatment). The study aims at a broader and better understanding of the situation of couples with an unfulfilled desire to have a child and of pathways leading couples to the fertility clinic. The approach of the study is interdisciplinary. It is designed as a prospective cohort study in a clinical setting. The study population consists of couples with an unfulfilled desire to have a child who presented themselves in a fertility clinic in the German state of Rhineland-Palatinate (RP) or in the capital city of the state of Hesse between July 2012 and May 2013. Self-administered questionnaires were used to gather information from patients at fertility clinics. These were handed out to the patients by the staff at the fertility clinics. Questionnaires returned by the end of July 2013 were included in the data set. The final sample consists of 323 female and 242 male respondents. In 234 couples, both partners participated. The overall response rate is 31%, with considerable variation across the clinics - reasons for and consequences of this are discussed. The final sample is described in terms of the distribution of core socio-demographic variables

The PinK Study - Methodology of the Follow-up Survey of a Cohort Study of Couples Undergoing Fertility Treatment

The paper describes the follow-up survey of the PinK study 'Paare in Kinderwunschbehandlung' (couples undergoing fertility treatment). This interdisciplinary study aims at a broader and better understanding of the situation of couples with an unfulfilled desire to have a child. The focus in the follow-up survey is on the situation of the couples one year after their first visit to a fertility clinic in Rhineland-Palatinate or in the capital of Hesse, Wiesbaden. Approximately one year after the baseline survey, self-administered questionnaires were sent to respondents who had signed a written agreement to remain in the study. The field period lasted from June 2013 to August 2014. The final sample consists of 140 women and 93 men. In 89 couples both partners participated. The longitudinal data set includes 224 respondents. The share of baseline survey participants who also participated in the follow-up is 39.6 %. This report describes the study design and materials for the follow-up as well as the sample and analyses the selectivity of dropouts from the baseline sample

Similar glycaemic control and less hypoglycaemia during active titration after insulin initiation with glargine 300 units/mL and degludec 100 units/mL: A subanalysis of the BRIGHT study

Aim: To further investigate glycaemic control and hypoglycaemia in BRIGHT, focusing on the titration period. Materials and Methods: BRIGHT was a multicentre, open-label, randomized, active-controlled, two-arm, parallel-group, 24-week study in insulin-naïve patients with uncontrolled type 2 diabetes initiated on glargine 300 U/mL (Gla-300) (N = 466) or degludec (IDeg-100) (N = 463). Predefined efficacy and safety outcomes were investigated during the initial 12-week titration period. In addition, patients’ characteristics and clinical outcomes were assessed descriptively, stratified by confirmed (≤3.9 mmol/L) hypoglycaemia incidence during the initial titration period. Results: At week 12, HbA1c was comparable between Gla-300 (7.32%) and IDeg-100 (7.23%), with similar least squares (LS) mean reductions from baseline (−1.37% and − 1.39%, respectively; LS mean difference of 0.02; 95% confidence interval: −0.08 to 0.12). Patients who experienced hypoglycaemia during the initial titration period had numerically greater HbA1c reductions by week 12 than patients who did not (−1.46% vs. −1.28%), and higher incidence of anytime (24 hours; 73.3% vs. 35.7%) and nocturnal (00:00–06:00 hours; 30.0% vs. 11.9%) hypoglycaemia between weeks 13–24. Conclusions: The use of Gla-300 resulted in similar glycaemic control as IDeg-100 during the initial 12-week titration period of the BRIGHT study, when less anytime (24 hours) hypoglycaemia with Gla-300 versus IDeg-100 has been reported. Experiencing hypoglycaemia shortly after initiating Gla-300 or IDeg-100 may be associated with hypoglycaemia incidence in the longer term, potentially impacting glycaemic management

Ensemble modeling of very small ZnO nanoparticles

The detailed structural characterization of nanoparticles is a very important issue since it enables a precise understanding of their electronic, optical and magnetic properties. Here we introduce a new method for modeling the structure of very small particles by means of powder X-ray diffraction. Using thioglycerol-capped ZnO nanoparticles with a diameter of less than 3 nm as an example we demonstrate that our ensemble modeling method is superior to standard XRD methods like, e.g., Rietveld refinement. Besides fundamental properties (size, anisotropic shape and atomic structure) more sophisticated properties like imperfections in the lattice, a size distribution as well as strain and relaxation effects in the particles and-in particular-at their surface (surface relaxation effects) can be obtained. Ensemble properties, i.e., distributions of the particle size and other properties, can also be investigated which makes this method superior to imaging techniques like (high resolution) transmission electron microscopy or atomic force microscopy, in particular for very small nanoparticles. For the particles under study an excellent agreement of calculated and experimental X-ray diffraction patterns could be obtained with an ensemble of anisotropic polyhedral particles of three dominant sizes, wurtzite structure and a significant relaxation of Zn atoms close to the surface

Picosecond Nonlinear Relaxation of Photoinjected Carriers in a Single GaAs/AlGaAs Quantum Dot

Photoemission from a single self-organized GaAs/AlGaAs quantum dot (QD) is temporally resolved with picosecond time resolution. The emission spectra consisting of the multiexciton structures are observed to depend on the delay time and the excitation intensity. Quantitative agreement is found between the experimental data and the calculation based on a model which characterizes the successive relaxation of multiexcitons. Through the analysis we can determine the carrier relaxation time as a function of population of photoinjected carriers. Enhancement of the intra-dot carrier relaxation is demonstrated to be due to the carrier-carrier scattering inside a single QD.Comment: 4 pages, 4 figures, to be published in Phys. Rev. B, Rapid

Emergence of communities on a coevolutive model of wealth interchange

We present a model in which we investigate the structure and evolution of a random network that connects agents capable of exchanging wealth. Economic interactions between neighbors can occur only if the difference between their wealth is less than a threshold value that defines the width of the economic classes. If the interchange of wealth cannot be done, agents are reconnected with another randomly selected agent, allowing the network to evolve in time. On each interaction there is a probability of favoring the poorer agent, simulating the action of the government. We measure the Gini index, having real world values attached to reality. Besides the network structure showed a very close connection with the economic dynamic of the system.Comment: 5 pages, 7 figure

Modeling magnetospheric fields in the Jupiter system

The various processes which generate magnetic fields within the Jupiter system are exemplary for a large class of similar processes occurring at other planets in the solar system, but also around extrasolar planets. Jupiter's large internal dynamo magnetic field generates a gigantic magnetosphere, which is strongly rotational driven and possesses large plasma sources located deeply within the magnetosphere. The combination of the latter two effects is the primary reason for Jupiter's main auroral ovals. Jupiter's moon Ganymede is the only known moon with an intrinsic dynamo magnetic field, which generates a mini-magnetosphere located within Jupiter's larger magnetosphere including two auroral ovals. Ganymede's magnetosphere is qualitatively different compared to the one from Jupiter. It possesses no bow shock but develops Alfv\'en wings similar to most of the extrasolar planets which orbit their host stars within 0.1 AU. New numerical models of Jupiter's and Ganymede's magnetospheres presented here provide quantitative insight into the processes that maintain these magnetospheres. Jupiter's magnetospheric field is approximately time-periodic at the locations of Jupiter's moons and induces secondary magnetic fields in electrically conductive layers such as subsurface oceans. In the case of Ganymede, these secondary magnetic fields influence the oscillation of the location of its auroral ovals. Based on dedicated Hubble Space Telescope observations, an analysis of the amplitudes of the auroral oscillations provides evidence that Ganymede harbors a subsurface ocean. Callisto in contrast does not possess a mini-magnetosphere, but still shows a perturbed magnetic field environment. Callisto's ionosphere and atmospheric UV emission is different compared to the other Galilean satellites as it is primarily been generated by solar photons compared to magnetospheric electrons.Comment: Chapter for Book: Planetary Magnetis