On divergent 3-vertices in noncommutative SU(2)gauge theory

We analyze divergencies in 2-point and 3-point functions for noncommutative $\theta$-expanded SU(2)-gauge theory with massless fermions. We show that, after field redefinition and renormalization of couplings, one divergent term remains.Comment: 7 page

Improving Soil Productivity and Increasing Lowland Rice Yields through the Integration of Organic and Inorganic Fertilizers in the Savannah and Forest Agro-ecological Zones of La Cote d’Ívoire

Sole mineral fertilizers use by poorly resourced farmers for rice production in the lowlands is usually low and unsustainable. Field experiments were therefore conducted within two contrasting environments (Forest and Savannah), using two common organic amendments (Poultry manure and Cattle manure) to establish an effective and integrated soil nutrient management system for improved lowland soil productivity and increased rice yields. The study was also partly intended to encourage and promote the effective and sustainable use of locally available organic amendments for nutrient management in lowland rice production. Results showed that organic amendments {cattle manure (CM) and poultry manure (PM)} contributed significantly to grain yield increases and total productivity with PM having a significantly greater and positive effect on grain yield than CM. In addition, the application of organic amendments in combination with mineral fertilizer significantly contributed to increased grain yield over the application of sole mineral fertilizer. Within the savannah agro- cological zone, there was a 130% (CM) and 203% (PM) grain yield increase over the control due to the application of organic amendments . When organic amendments were applied in combination with mineral fertilizer (MF), grain yield increased by 21% and 43% over sole MF for CM and PM respectively. However, sole CM contributed 12% increase in grain yield over the control while PM gave a 35% increase within the forest agro- cological zone. The combined application of MF and CM resulted in an 11% increase in grain yield while MF and PM combinations produced a 30% yield increase within the ecology. The non-addition of N, P, K as mineral fertilizer resulted in a yield reduction of about 84% at both sites. Resource poor farmers within the West African sub-region should therefore be encouraged to use organic amendments, which are not only available locally but also affordable. Proper storage and handling of these organic materials is very important to minimize nutrient losses.&nbsp

Learning from model errors: Can land use, edaphic and very high-resolution topo-climatic factors improve macroecological models of mountain grasslands?

Aim: Assess the potential of new predictors (land use, edaphic factors and high-resolution topographic and climatic variables, i.e., topo-climatic) to improve the prediction of plant community functional traits (specific leaf area, vegetative height and seed mass) and species richness in models of mountain grasslands. Location: The western Swiss Alps Methods: Using 912 grassland plots, we constructed predictive models for community-weighted means of plant traits and species richness using high resolution (25 m) topo-climatic predictors traditionally used in previous modelling studies in this area. In addition, 78 new plots were sampled for evaluation and error assessment in four narrower sets of homogenous conditions based on predictions by the topo-climatic models within two elevation belts (montane and alpine). New, finer-scale predictors were generated from direct field measurements or very high-resolution (5 m) numerical data. We then used multimodel inference to test the capacity of these finer predictors to explain part of the residual variance in the initial topo-climatic models. Results: We showed that the finer-scale predictors explained up to 44% of the residual variance in the classical topo-climatic models. The very high-resolution topographic position, soil C/N ratio and pH performed notably well in our analysis. Land use (farming intensity) was highlighted as potentially important in montane grasslands, but improvements were only significant for species richness predictions. Main conclusions: Compared with classical topo-climatic models, the new, finer-scale predictors significantly improved the prediction of all traits and species richness in alpine plant communities and that of specific leaf area and richness in montane grasslands. The differences in the importance of the predictors, dependent on both trait and position along the elevation gradient, highlight the different factors that shape the distribution of species and communities along elevation gradients

Non-renormalizability of noncommutative SU(2) gauge theory

We analyze the divergent part of the one-loop effective action for the noncommutative SU(2) gauge theory coupled to the fermions in the fundamental representation. We show that the divergencies in the 2-point and the 3-point functions in the $\theta$-linear order can be renormalized, while the divergence in the 4-point fermionic function cannot.Comment: 15 pages, results presented at ESI 2d dilaton gravity worksho

Supraglacial debris thickness and supply rate in High-Mountain Asia

Supraglacial debris strongly modulates glacier melt rates and can be decisive for ice dynamics and mountain hydrology. It is ubiquitous in High-Mountain Asia, yet because its thickness and supply rate from local topography are poorly known, our ability to forecast regional glacier change and streamflow is limited. Here we combined remote sensing and numerical modelling to resolve supraglacial debris thickness by altitude for 4689 glaciers in High-Mountain Asia, and debris-supply rate to 4141 of those glaciers. Our results reveal extensively thin supraglacial debris and high spatial variability in both debris thickness and supply rate. Debris-supply rate increases with the temperature and slope of debris-supply slopes regionally, and debris thickness increases as ice flow decreases locally. Our centennial-scale estimates of debris-supply rate are typically an order of magnitude or more lower than millennial-scale estimates of headwall-erosion rate from Beryllium-10 cosmogenic nuclides, potentially reflecting episodic debris supply to the region’s glaciers

Near-extremal and extremal quantum-corrected two-dimensional charged black holes

We consider charged black holes within dilaton gravity with exponential-linear dependence of action coefficients on dilaton and minimal coupling to quantum scalar fields. This includes, in particular, CGHS and RST black holes in the uncharged limit. For non-extremal configuration quantum correction to the total mass, Hawking temperature, electric potential and metric are found explicitly and shown to obey the first generalized law. We also demonstrate that quantum-corrected extremal black holes in these theories do exist and correspond to the classically forbidden region of parameters in the sense that the total mass $M_{tot}<Q$ ($Q$ is a charge). We show that in the limit $T_{H}\to 0$ (where $T_{H}$ is the Hawking temperature) the mass and geometry of non-extremal configuration go smoothly to those of the extremal one, except from the narrow near-horizon region. In the vicinity of the horizon the quantum-corrected geometry (however small quantum the coupling parameter $\kappa$ would be) of a non-extremal configuration tends to not the quantum-corrected extremal one but to the special branch of solutions with the constant dilaton (2D analog of the Bertotti-Robinson metric) instead. Meanwhile, if $\kappa =0$ exactly, the near-extremal configuration tends to the extremal one. We also consider the dilaton theory which corresponds classically to the spherically-symmetrical reduction from 4D case and show that for the quantum-corrected extremal black hole $M_{tot}>Q$.Comment: 25 pages. Typos corrected. To appear in Class. Quant. Gra

Interannual Dynamics of Ice Cliff Populations on Debris‐Covered Glaciers from Remote Sensing Observations and Stochastic Modeling

Ice cliffs are common on debris-covered glaciers and have relatively high melt rates due to their direct exposure to incoming radiation. Previous studies have shown that their number and relative area can change considerably from year to year, but this variability has not been explored, in part because available cliff observations are irregular. Here, we systematically mapped and tracked ice cliffs across four debris-covered glaciers in High Mountain Asia for every late ablation season from 2009 to 2019 using high-resolution multi-spectral satellite imagery. We then quantified the processes occurring at the feature scale to train a stochastic birth-death model to represent the cliff population dynamics. Our results show that while the cliff relative area can change by up to 20% from year to year, the natural long-term variability is constrained, thus defining a glacier-specific cliff carrying capacity. In a subsequent step, the inclusion of external drivers related to climate, glacier dynamics and hydrology highlights the influence of these variables on the cliff population dynamics, which is usually not a direct one due to the complexity and interdependence of the processes taking place at the glacier surface. In some extreme cases (here, a glacier surge), these external drivers may lead to a reorganization of the cliffs at the glacier surface and a change in the natural variability. These results have implications for the melt of debris-covered glaciers, in addition to showing the high rate of changes at their surface and highlighting some of the links between cliff population and glacier state