Spatial and temporal patterns of land surface temperature in the Mekong Basin

Land surface temperature (LST) is an essential part of the surface energy budget and can be used as a measure for climate variability and change, given that regular measurements on a broad spatial scale are available. The MODIS (Moderate Resolution Imaging Spectroradiometer) sensor offers a 13 years’ time series, which enables the analysis of spatial patterns along with the temporal evolution of the variable. Area of interest is the Mekong Basin (MB). It was analysed using MODIS LST data with a temporal granularity of 8-days. LST prove to be strongly dependent on the topography. 42% of daytime LST could be explained by topographic height in summer. In winter and generally in the night time scenes topography could explain 89-97% of the LST distribution. For further analysis the area of interest was divided into six physiographic homogenous regions. The mean temperature and the annual maximum and minimum values of LST are different for the various regions. Low temperatures coupled with large magnitudes are predominantly found in the high-lysing Tibetan Plateau, whereas the southern regions show high mean temperatures along with low magnitudes. There is a weak year-to-year variability of LST (regional 8-day daytime/night time deviations lower than 4°C/6°C) in all regions. However, over the Tibetan Plateau regional 8-day daytime/night time deviations reach 6°C and 18°C. Apart from the topography, LST is influenced by land use. As such, land use changes influence the LST pattern as is shown in this research on the example of deforestation in parts of Cambodia

Einfluss von Simulationen im Rahmen der Lehre der digitalen rektalen Untersuchung auf Hemmungen und Wissenserwerb von Studenten

In einem interdisziplinären Forschungsprojekt an der LMU München gehen Chirurgen und Psychologen gemeinsam der Frage nach, wie komplexe Fertigkeiten, zB. der Umgang mit Untersuchungssituationen, erlernt werden und wie dieser Prozess durch gezieltes Training unterstützt werden kann. Diese Studie untersucht die Wirksamkeit von Simulationsmethoden im Kurs zum Erlernen der digitalen rektalen Untersuchung (DRU). In dieser Dissertation werden verschiedene Varianten eines simulationsbasierten Trainings bezüglich ihrer Einwirkung auf Hemmungen, Motivation, Wissen und Akzeptanz untersucht.Die vorliegende Studie untersucht die Fragen, (1) in welchem Ausmaß die Komplexität der Simulation die Hemmung und den Wissenserwerb der Lernenden beeinflusst und (2) in welchem Ausmaß die Sequenz der Simulationen Hemmung und Wissenserwerb beeinflusst. Die Stichprobe bestand aus 100 Teilnehmern am Untersuchungskurs „digitale rektale Untersuchung“. Jeder Student nahm an zwei halbstündigen Simulationseinheiten teil. Eine Hälfte der Studenten übte zuerst am Rektalmodel, danach am Simulationspatient, die andere Hälfte in umgekehrter Reihenfolge. Dies ermöglichte einerseits den Vergleich der Effektivität der Simulationen per se (Unterschiede zwischen den Gruppen nach der ersten Unterrichtseinheit). Andererseits wurde auch die Wirksamkeit der Reihenfolge der eingesetzten Simulationen untersucht, indem Unterschiede zwischen den beiden Versuchsgruppen nach der Durchführung beider Unterrichtseinheiten gemessen wurden. Das Training am Simulationspatienten hat einen signifikant stärkeren Einfluß auf die Reduktion von Hemmungen als das Rektalmodell, unabhängig von der eingesetzten Sequenz. Der Wissenserwerb ist größer, wenn die Studenten zuerst am Rektalmodell und danach am Simulationspatient üben. Nutzen sie nur eine Simulation, ist kein Wissenserwerb nachweisbar. Die Simulationspatienten sind durch andere Lehrmethoden nicht ersetzbar, da sie den Studenten durch wiederholtes Training in realitätsnaher Lernumgebung ermöglichen, an allen Aspekten der DRU mit Berücksichtigung ihrer individuellen Schwächen zu arbeiten

Value adjustments and dynamic hedging of reinsurance counterparty risk

Reinsurance counterparty credit risk (RCCR) is the risk of a loss arising from the fact that a reinsurance company is unable to fulfill her contractual obligations towards the ceding insurer. RCCR is an important risk category for insurance companies which, so far, has been addressed mostly via qualitative approaches. In this paper we therefore study value adjustments and dynamic hedging for RCCR. We propose a novel model that accounts for contagion effects between the default of the reinsurer and the price of the reinsurance contract. We characterize the value adjustment in a reinsurance contract via a partial integro-differential equation (PIDE) and derive the hedging strategies using a quadratic method. The paper closes with a simulation study which shows that dynamic hedging strategies have the potential to significantly reduce RCCR.Comment: 27 pages, 8 figure

Distribution of cadmium in leaves of Thlaspi caerulescens

Knowledge of the intracellular distribution of Cd in leaves is necessary in order to understand the mechanisms of hyperaccumulation in Thlaspi caerulescens. Ganges and Prayon, two ecotypes accumulating Cd to different levels, were grown in nutrient medium containing varying concentrations (0, 5, 10, 50, and 100 μM) of Cd. Several different approaches were combined in this study to (i) validate the results obtained by a specific method and (ii) establish the link between observations and measurements performed at different scales. In both ecotypes, Cd, localized by autoradiography, was found mainly at the edges of the leaves, but also in points of higher concentration spread over the whole limb surface. This localization was clearly correlated with the necrotic spots observed on Prayon leaves. Scanning electron microscopy coupled with energy dispersive X-ray microanalysis (cryo-SEM-EDXMA) and tissue fractionation (apoplasm, cell walls, mesophyll protoplasts, and lower epidermis) showed that Cd had similar patterns of distribution in leaf cells of both ecotypes. Cadmium was found both inside the cells and in the cell walls, mainly in the large epidermal cells but also in small epidermal cells. All the methods used agreed well and the results indicated that metal storage in the plants studied involves more than one compartment and that Cd is stored principally in the less metabolically active parts of leaf cell

Follow-up of bone mineral density changes in de novo kidney transplant recipients treated with two doses of the receptor activator of nuclear factor κB ligand inhibitor denosumab

BACKGROUND: Studies in women with post-menopausal osteoporosis have shown that discontinuation of treatment with denosumab leads to an increased risk of vertebral fractures because of rebound bone turnover and rapid loss of bone mineral density (BMD). METHODS: In a post hoc analysis of the Prolia for Osteoporosis of Transplant Operated Patient study, we analyzed the effect of denosumab withdrawal on BMD changes. Twenty-five de novo kidney transplant recipients (KTR) who were treated for 1 year with 2 six-monthly doses of denosumab on top of standard treatment (daily calcium and vitamin D) were compared to a control group of 29 KTR who received standard treatment alone. BMD changes were analyzed by repeated dual-energy X-ray absorptiometry shortly after transplantation (baseline), after 6 and 12 months (active treatment phase) and after 2-6.5 years (follow-up phase). RESULTS: The average BMD at the lumbar spine declined markedly after discontinuation of treatment with denosumab but increased again thereafter. Thus, the average monthly change in lumbar spine BMD from month 12 onward was only 0.1 ± 2.8‰ in the denosumab group but 1.5 ± 1.9‰ in the control group (p = 0.021). The average monthly change in lumbar spine BMD from baseline to follow-up was similar in the control and denosumab group (1.1 ± 1.2‰ vs. 1.5 ± 2.4‰, p = 0.788). Similar results were seen at the total hip. CONCLUSIONS: In de novo KTR treated with 2 doses of denosumab, we detect a marked decrease in lumbar spine and hip BMD when denosumab is discontinued. Denosumab treatment should therefore not be discontinued without considering an alternative antiresorptive treatment

Compliance of young children with ITN protection in rural Burkina Faso

BACKGROUND: Insecticide-treated bed nets (ITNs) are known to be highly effective in reducing malaria morbidity and mortality. The effectiveness of ITNs is largely influenced by behavioural factors and not much is known regarding such factors under programme conditions. METHODS: This descriptive study was nested into a large ITN effectiveness study in rural Burkina Faso. During two cross-sectional surveys in the dry and rainy season of 2003, random samples of young children from nine representative villages (n = 180 per survey) were investigated for compliance with ITN protection and related behaviour. Data were collected through direct observations and through interviews with mothers. RESULTS: ITNs were perceived as very important for protection against mosquitoes and malaria particularly during the rainy season, but there were problems with their use during the dry season. Young children usually slept with their mother under the ITN and self-reported compliance was 66% and 98% during dry and rainy season, respectively (confirmed by direct observation in 34% and 79%, respectively). Important reasons for low compliance during the dry season were high temperatures inside houses and problems related to changing sleeping places during the night. CONCLUSION: Under programme conditions, compliance with ITN protection in young children is sufficient during the rainy season, but is rather low during the hot and dry season. Greater emphasis needs to be placed on information/education efforts to make people aware of the fact that the risk of contracting malaria may persist throughout the year

Microbial niche differentiation explains nitrite oxidation in marine oxygen minimum zones

Nitrite is a pivotal component of the marine nitrogen cycle. The fate of nitrite determines the loss or retention of fixed nitrogen, an essential nutrient for all organisms. Loss occurs via anaerobic nitrite reduction to gases during denitrification and anammox, while retention occurs via nitrite oxidation to nitrate. Nitrite oxidation is usually represented in biogeochemical models by one kinetic parameter and one oxygen threshold, below which nitrite oxidation is set to zero. Here we find that the responses of nitrite oxidation to nitrite and oxygen concentrations vary along a redox gradient in a Pacific Ocean oxygen minimum zone, indicating niche differentiation of nitrite-oxidizing assemblages. Notably, we observe the full inhibition of nitrite oxidation by oxygen addition and nitrite oxidation coupled with nitrogen loss in the absence of oxygen consumption in samples collected from anoxic waters. Nitrite-oxidizing bacteria, including novel clades with high relative abundance in anoxic depths, were also detected in the same samples. Mechanisms corresponding to niche differentiation of nitrite-oxidizing bacteria across the redox gradient are considered. Implementing these mechanisms in biogeochemical models has a significant effect on the estimated fixed nitrogen budget

Induction of Krüppel-Like Factor 4 Mediates Polymorphonuclear Neutrophil Activation in Streptococcus pneumoniae Infection

The recruitment and activation of polymorphonuclear neutrophils (PMNs) are of central importance for the elimination of pathogens in bacterial infections. We investigated the Streptococcus pneumoniae-dependent induction of the transcription factor Kruppel-like factor (KLF) 4 in PMNs as a potential regulator of PMN activation. We found that KLF4 expression is induced in human blood-derived PMNs in a time- and dose-dependent manner by wild-type S. pneumoniae and capsule knockout mutants. Unencapsulated knockout mutants induced stronger KLF4 expression than encapsulated wild types. The presence of autolysin LytA-competent (thus viable) pneumococci and LytA-mediated bacterial autolysis were required for KLF4 induction in human and murine PMNs. LyzMcre-mediated knockdown of KLF4 in murine blood-derived PMNs revealed that KLF4 influences pneumococci killing and increases the release of the proinflammatory cytokines tumor necrosis factor alpha and keratinocyte chemoattractant and decreases the release of the anti-inflammatory cytokine interleukin-10. Thus, S. pneumoniae induces KLF4 expression in PMNs, which contributes to PMN activation in S. pneumoniae infection

Investigations on the interplays between Schistosoma mansoni, praziquantel and the gut microbiome

Schistosomiasis is a neglected tropical disease burdening millions of people. One drug, praziquantel, is currently used for treatment and control. Clinically relevant drug resistance has not yet been described, but there is considerable heterogeneity in treatment outcomes, ranging from cure to only moderate egg reduction rates. The objectives of this study are to investigate potential worm-induced dysbacteriosis of the gut microbiota and to assess whether a specific microbiome profile could influence praziquantel response.; Using V3 and V4 regions of 16S rRNA genes, we screened the gut microbiota of 34 Schistosoma mansoni infected and uninfected children from Côte d'Ivoire. From each infected child one pre-treatment, one 24-hour and one 21-day follow-up sample after administering 60 mg/kg praziquantel or placebo, were collected.; Overall taxonomic profiling and diversity indicators were found to be close to a "healthy" gut structure in all children. Slight overall compositional changes were observed between S. mansoni-infected and non-infected children. Praziquantel treatment was not linked to a major shift in the gut taxonomic profiles, thus reinforcing the good safety profile of the drug by ruling out off-targets effects on the gut microbes.16S rRNA gene of the Fusobacteriales order was significantly more abundant in cured individuals, both at baseline and 24 hours post-treatment. A real-time qPCR confirmed the over-abundance of Fusobacterium spp. in cured children. Fusobacterium spp. abundance could also be correlated with treatment induced S. mansoni egg-reduction.; Our study suggests that neither a S. mansoni infection nor praziquantel administration triggers a significant effect on the microbial composition and that a higher abundance of Fusobacterium spp., before treatment, is associated with higher efficacy of praziquantel in the treatment of S. mansoni infections.; International Standard Randomised Controlled Trial, number ISRCTN15280205