Adaptive Step Size for Hybrid Monte Carlo Algorithm

We implement an adaptive step size method for the Hybrid Monte Carlo a lgorithm. The adaptive step size is given by solving a symmetric error equation. An integr ator with such an adaptive step size is reversible. Although we observe appreciable variations of the step size, the overhead of the method exceeds its benefits. We propose an explanation for this phenomenon.Comment: 13 pages, 5 Postscript figures, late

Assessment of the impacts of clear-cutting on soil loss by water erosion in Italian forests: First comprehensive monitoring and modelling approach

Abstract As a member of the European Union, Italy has committed to the maintenance and protection of its forests based on sustainable forest development and management practices. According to Eurostat, Italy has the seventh largest forest surface available for wood supply in the EU-28, which is equal to 8.086 million hectares. For 2012, the Italian National Institute of Statistics estimated the total roundwood production of Italy to be 7.7 million m3, from a harvested forest surface of 61,038 ha. Large parts of the country's forests, mainly located in vulnerable mountainous landscapes that are highly sensitive to environmental changes, are subject to anthropogenic disturbance driven by wood supply interests. Despite the extensive logging activities and the well-known impacts that such management practices have on the soil-related forest ecosystems, there is a lack of spatially and temporally explicit information about the removal of trees. Hence, this study aims to: i) assess the soil loss by water erosion in Italian forest areas, ii) map forest harvests and iii) evaluate the effects of logging activities in terms of soil loss by means of comprehensive remote sensing and GIS modelling techniques. The study area covers about 785.6 × 104 ha, which corresponds to the main forest units of the CORINE land cover 2006 database (i.e. broad-leaved forests, coniferous forests and mixed forests). Annual forest logging activities were mapped using Landsat imagery. Validation procedures were applied. A revised version of the Universal Soil Loss Equation (USLE) was used to predict the soil loss potential due to rill and inter-rill processes. To ensure a thorough modelling approach, the input parameters were calculated using the original methods reported in the USDA handbooks. The derived high-resolution data regarding forest cover change shows that 317,535 ha (4.04% of the total forest area in Italy) were harvested during the period under review. The predicted long-term annual average soil loss rate was 0.54 Mg ha− 1 yr− 1. The average rate of soil loss in forests that remained undisturbed during the modelled period is equal to 0.33 Mg ha− 1 yr− 1. Notably, about half of the soil loss (45.3%) was predicted for the logged areas, even though these cover only about 10.6% of the Italian forests. The identified erosion hotspots may represent a serious threat for the soil-related forest ecosystems, and are in contrast to the EC Thematic Strategy for Soil Protection and Water Framework Directive

Monte Carlo simulations and field transformation: the scalar case

We describe a new method in lattice field theory to compute observables at various values of the parameters lambda_i in the action S[phi,lambda_i]. Firstly one performs a single simulation of a ``reference action'' S[phi^r, lambda_i^r] with fixed lambda_i^r. Then the phi^r-configurations are transformed into those of a field phi distributed according to S[phi,lambda_i], apart from a ``remainder action'' which enters as a \break weight. In this way we measure the observables at values of lambda_i different from lambda_i^r. We study the performance of the algorithm in the case of the simplest renormalizable model, namely the phi^4 scalar theory on a four dimensional lattice and compare the method with the ``histogram'' technique of which it is a generalization.Comment: Latex, 23 pgs, 8 eps-figures include

Report on advances for pediatricians in 2018: allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery.

This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient car

Current Renormalisation Constants with an O(a)-improved Fermion Action

Using chiral Ward identities, we determine the renormalisation constants of bilinear quark operators for the Sheikholeslami-Wohlert action lattice at beta=6.2. The results are obtained with a high degree of accuracy. For the vector current renormalisation constant we obtain Z_V=0.817(2)(8), where the first error is statistical and the second is due to mass dependence of Z_V. This is close to the perturbative value of 0.83. For the axial current renormalisation constant we obtain Z_A = 1.045(+10 -14), significantly higher than the value obtained in perturbation theory. This is shown to reduce the difference between lattice estimates and the experimental values for the pseudoscalar meson decay constants, but a significant discrepancy remains. The ratio of pseudoscalar to scalar renormalisation constants, Z_P/Z_S, is less well determined, but seems to be slightly lower than the perturbative value.Comment: 8 pages uuencoded compressed postscript file. Article to be submitted to Phys.Rev.

Re-evaluating Surface Application Rates for Texas OSSF Systems

Approximately 25% of the nation’s housing units utilize on-site treatment and disposal systems. Mostly, on-site treatment consists of a septic tank-soil adsorption configuration, though surface disposal systems are used in areas where the soil is not suitable for an adsorption field. One of the concerns with the use of on-site sewage treatment systems is the potential for nitrate pollution of the groundwater resources. Current procedures for designing surface application systems for on-site sewage facilities (OSSFs), with an emphasis on aerobic systems, in Texas have been reviewed. Concerns with the current procedures for designing sprinkler systems include the sizing of the spray field area, the volume of effluent storage required, and the absence of the uniformity of sprinkler distribution patterns. Currently the spray field area is determined by the estimated daily volume of water applied divided irrigation water requirement (evaporation minus precipitation). A proper design needs to be adaptable to the many climates and soils that exist within the state, while maintaining the integrity of the environment. To meet this goal, an alternative, easy to follow, design procedure is proposed. The proposed design method incorporates the concept of water application rate, soil infiltration rate, crop water use, crop nutrient uptake rate, water application efficiency, and irrigation layout design and nozzle selection. With any surface application system for wastewater effluent, control of the nitrogen applied is essential to minimize the impact on regional water resources, whether surface water or ground water. If an OSSF is designed with a typical type of sprinkler and no overlap of the spray pattern is provided, the potential mass of nitrogen that can move below the crops root zone can be substantial. The quantity of nitrogen that could potentially move below the crops root zone ranges from 16 percent of the nitrogen applied in East Texas to 59 percent of the nitrogen applied in West Texas. Poor distribution of the effluent applied on portions of the spray field may cause the nutrients (e.g. nitrate-nitrogen) to be applied at levels exceeding the plants assimilation capacity. If a sprinkler design provides an overlapping spray pattern and the wastewater application rate is limited based on the crops ability to utilize the applied nitrogen, the nitrogen that could potentially move below the crops root zone can be limited to 7 percent of the total nitrogen applied or less. This limited nitrogen movement is realized when the wastewater distribution uniformity coefficient is 80 percent or greater. Another advantage of the proposed design procedure is the smaller land area requirement in some parts of the state. In east Texas for example, the land area reduction is about 27 percent while the land area required in West Texas increases by two times. The additional system requirements under the proposed design procedure are an increase in the number of sprinkler heads and a zone sprinkler controller. This latter device is required to cycle the application of the wastewater effluent to the various quadrants of the spray field. It is recommended that the following changes be made to the current Texas Administrative Code 285 rules in order to provide for the least amount of negative impact our the states environment. All surface application systems designed for an on-site sewage facility should consider both a water balance and a nutrient balance for the final design. The layout of the site for effluent application should be in a block pattern such that the sprinklers can be arranged to have a head-to-head overlap. If this is not available, then the system should be designed such that the proper overlap can be provided in order to achieve a uniformity coefficient of 80 percent or greater. Spray head type of sprinklers should not be used in an OSSF system while the gear head type should be used. All sprinklers are designed to operate at an optimum pressure range to obtain the specified pattern of water distribution and the OSSF design pressure should be in the middle of the specified range. Sprinklers operating at pressures lower or higher than designed will produce unreliable patterns that will result in very low water application efficiencies and low application uniformity. The time used to apply the effluent should not exceed 1 hour and the average design should be 0.5 hours. The base water intake rate of the soil should follow that described by Saxton et al. (1986) provided more precise information on the soil is not available. The base soil infiltration rate should be set equal to the saturated hydraulic conductivity of the top 18 inches of soil. A check-off list of design considerations should be developed and used on all new and renovated designs of OSSF where surface application of the effluent is utilized