Fully Off-shell Effective Action and its Supersymmetry in Matrix Theory

As a step toward clarification of the power of supersymmetry (SUSY) in Matrix theory, a complete calculation, including all the spin effects, is performed of the effective action of a probe D-particle, moving along an arbitrary trajectory in interaction with a large number of coincident source D-particles, at one loop at order 4 in the derivative expansion. Furthermore, exploiting the SUSY Ward identity developed previously, the quantum-corrected effective supersymmetry transformation laws are obtained explicitly to the relevant order and are used to verify the SUSY-invariance of the effective action. Assuming that the agreement with 11-dimensional supergravity persists, our result can be regarded as a prediction for supergravity calculation, which, yet unavailable, is known to be highly non-trivial.Comment: 27 page

Structure in Supersymmetric Yang-Mills Theory

We show that requiring sixteen supersymmetries in quantum mechanical gauge theory implies the existence of a web of constrained interactions. Contrary to conventional wisdom, these constraints extend to arbitrary orders in the momentum expansion.Comment: 22 pages, LaTe

The Dirac field in Taub-NUT background

We investigate the SO(4,1) gauge-invariant theory of the Dirac fermions in the external field of the Kaluza-Klein monopole, pointing out that the quantum modes can be recovered from a Klein-Gordon equation analogous to the Schr\" odinger equation in the Taub-NUT background. Moreover, we show that there is a large collection of observables that can be directly derived from those of the scalar theory. These offer many possibilities of choosing complete sets of commuting operators which determine the quantum modes. In addition there are some spin- like and Dirac-type operators involving the covariantly constant Killing-Yano tensors of the hyper-K\" ahler Taub-NUT space. The energy eigenspinors of the central modes in spherical coordinates are completely evaluated in explicit, closed form.Comment: 20 pages, latex, no figure

SU(3)_c X SU(4)_L X U(1)_x model for three families

An extension of the Standard Model to the local gauge group $SU(3)_c\otimes SU(4)_L\otimes U(1)_X$ as a three-family model is presented. The model does not contain exotic electric charges and we obtain a consistent mass spectrum by introducing an anomaly-free discrete $Z_2$ symmetry. The neutral currents coupled to all neutral vector bosons in the model are studied. By using experimental results from the CERN LEP, SLAC Linear Collider and atomic parity violation we constrain the mixing angle between two of the neutral currents in the model and the mass of the additional neutral gauge bosons to be $-0.0032\leq\sin\theta\leq 0.0031$ and $0.67 \hbox{TeV}\leq M_{Z_2} \leq 6.1$ TeV at 95% C.L., respectively.Comment: 7 pages, 1 figure, uses EPJ style. Accepted for publication in Eur. Phys. J.

A water availability and low-flow analysis of the Tagliamento River discharge in Italy under changing climate conditions

This study estimated the effects of projected variations in precipitation and temperature on snowfall-snowmelt processes and subsequent river discharge variations in the Tagliamento River in Italy. A lumped-parameter, non-linear, rainfall-runoff model with 10 general circulation model (GCM) scenarios was used. Spatial and temporal changes in snow cover were assessed using 15 high-quality Landsat images. The 7Q10 low-flow probability distribution approximated by the Log-Pearson type III distribution function was used to examine river discharge variations with respect to climate extremes in the future. On average, the results obtained for 10 scenarios indicate a consistent warming rate for all time periods, which may increase the maximum and minimum temperatures by 2.3 °C (0.6–3.7 °C) and 2.7 °C (1.0–4.0 °C), respectively, by the end of the 21st century compared to the present climate. Consequently, the exponential rate of frost day decrease for 1 °C winter warming in lower-elevation areas is approximately three-fold (262%) higher than that in higher-elevation areas, revealing that snowfall in lower-elevation areas will be more vulnerable under a changing climate. In spite of the relatively minor changes in annual precipitation (−17.4 ~ 1.7% compared to the average of the baseline (1991–2010) period), snowfall will likely decrease by 48–67% during the 2080–2099 time period. The mean river discharges are projected to decrease in all seasons, except winter. The low-flow analysis indicated that while the magnitude of the minimum river discharge will increase (e.g. a 25% increase in the 7Q10 estimations for the winter season in the 2080–2099 time period), the number of annual average low-flow events will also increase (e.g. 16 and 15 more days during the spring and summer seasons, respectively, in the 2080–2099 time period compared to the average during the baseline period), leading to a future with a highly variable river discharge. Moreover, a consistent shift in river discharge timing would eventually cause snowmelt-generated river discharge to occur approximately 12 days earlier during the 2080–2099 time period compared to the baseline climate. These results are expected to raise the concern of policy makers, leading to the development of new water management strategies in the Tagliamento River basin to cope with changing climate conditions

Probabilistic modelling of rainfall induced landslide hazard assessment

To evaluate the frequency and distribution of landslides hazards over Japan, this study uses a probabilistic model based on multiple logistic regression analysis. Study particular concerns several important physical parameters such as hydraulic parameters, geographical parameters and the geological parameters which are considered to be influential in the occurrence of landslides. Sensitivity analysis confirmed that hydrological parameter (hydraulic gradient) is the most influential factor in the occurrence of landslides. Therefore, the hydraulic gradient is used as the main hydraulic parameter; dynamic factor which includes the effect of heavy rainfall and their return period. Using the constructed spatial data-sets, a multiple logistic regression model is applied and landslide hazard probability maps are produced showing the spatial-temporal distribution of landslide hazard probability over Japan. To represent the landslide hazard in different temporal scales, extreme precipitation in 5 years, 30 years, and 100 years return periods are used for the evaluation. The results show that the highest landslide hazard probability exists in the mountain ranges on the western side of Japan (Japan Sea side), including the Hida and Kiso, Iide and the Asahi mountainous range, the south side of Chugoku mountainous range, the south side of Kyusu mountainous and the Dewa mountainous range and the Hokuriku region. The developed landslide hazard probability maps in this study will assist authorities, policy makers and decision makers, who are responsible for infrastructural planning and development, as they can identify landslide-susceptible areas and thus decrease landslide damage through proper preparation

Assessment of snowmelt triggered landslide hazard and risk in Japan

This study is pertaining to an evaluation of landslide occurrence on natural terrain due to snowmelt in Japan, using a probabilistic model based on multiple logistic regression analysis. The evaluation concerns several physical parameters such as hydraulic parameters, geographical parameters and geological parameters which are considered to be influential in the occurrence of landslides. A Snow Water Equivalent model (SWE) is utilized to estimate snowmelt and associated infiltration in light, heavy and normal snow years. Using the constructed spatial data-sets, we apply a multiple logistic regression model to produce landslide susceptibility maps showing the spatial–temporal distribution of landslide hazard probabilities throughout Japan using 1 km × 1 km resolution grid cells. The results have revealed that, over 95% landslide hazard probability exists in the mountain ranges on the western side of Japan (the Japan Sea side). In particular, this study is dealing with the Aizu region of Fukushima prefecture in order to verifying the landslide hazard probability. Verification proved that, the areas identified as high risk areas (having over 90% landslide hazard probability in numerical modeling) show 87% agreement with observed landslides in the Aizu region. Also we evaluated the relationship between landslides and snow melting process giving special concern to change of temperature in the spring

Quantum Metamorphosis of Conformal Transformation in D3-Brane Yang-Mills Theory

We show how the linear special conformal transformation in four-dimensional N=4 super Yang-Mills theory is metamorphosed into the nonlinear and field-dependent transformation for the collective coordinates of Dirichlet 3-branes, which agrees with the transformation law for the space-time coordinates in the anti-de Sitter (AdS) space-time. Our result provides a new and strong support for the conjectured relation between AdS supergravity and super conformal Yang-Mills theory (SYM). Furthermore, our work sheds elucidating light on the nature of the AdS/SYM correspondence.Comment: 8 pages, no figure

A Unified Approach to Solvable Models of Dilaton Gravity in Two-Dimensions Based on Symmetry

A large class of solvable models of dilaton gravity in two space-time dimensions, capable of describing black hole geometry, are analyzed in a unified way as non-linear sigma models possessing a special symmetry. This symmetry, which can be neatly formulated in the target-space-covariant manner, allows one to decompose the non-linearly interacting dilaton-gravity system into a free field and a field satisfying the Liouville equation with in general non-vanishing cosmological term. In this formulation, all the existent models are shown to fall into the category with vanishing cosmological constant. General analysis of the space-time structureinduced by a matter shock wave is performed and new models, with and without the cosmological term, are discussed.Comment: 29 pages, LaTe