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We study a nonhierarchical tritrophic system, whose predator-prey interactions are described by the rock-paper-scissors game rules. In our stochastic simulations, individuals may move strategically towards the direction with more conspecifics to form clumps instead of moving aimlessly on the lattice. Considering that the conditioning to move gregariously depends on the organism's physical and cognitive abilities, we introduce a maximum distance an individual can perceive the environment and a minimum conditioning level to perform the gregarious movement. We investigate the pattern formation and compute the average size of the single-species spatial domains emerging from the grouping behaviour. The results reveal that the defence tactic reduces the predation risk significantly, being more profitable if individuals perceive further distances, thus creating bigger groups. Our outcomes show that the species with more conditioned organisms dominate the cyclic spatial game, controlling most of the territory. On the other hand, the species with fewer individuals ready to perform aggregation strategy gives its predator the chance to fill the more significant fraction of the grid. The spatial interactions assumed in our numerical experiments constitute a data set that may help biologists and data scientists understand how local interactions influence ecosystem dynamics. • Stochastic simulations of the spatial rock-paper-scissors model with behavioural movement of aggregation were performed. • The emergence of single-species spatial domains caused by gregarious movement is demonstrated. • The benefits of the aggregation strategy in reducing predation risk are calculated. • The impact of the organisms' conditioning in the dynamics of species densities is quantified. [ABSTRACT FROM AUTHOR]

Abstract: Density functional theory was used to study the adsorption of hydrogen on small palladium clusters (Pd n , n = 1–4) supported on pyridine-like nitrogen doped graphene. Charge transfer and strong binding (up to four times higher than binding energy of Pd cluster supported on graphene) between graphene–nitrogen and palladium clusters prevent detachment of clusters and leads to three types of adsorption states of hydrogen. The first type is a molecular hydrogen physisorbed, the second one is an activated state of H2 without adsorption barriers where H–H bond is relaxed and the third type is dissociated state. In dissociated cases, we found barriers below 0.56 eV. This means the process might occur spontaneously at room temperature. We also show that metal–N–vacancy complexes are very stable and involve nitrogen sp2 and pz, carbon pz and palladium d orbitals. Besides, these systems exhibit an interesting magnetic behavior. [Copyright &y& Elsevier]

Abstract: Density functional theory and molecular dynamics were used to study the interaction of a lithium atom with a vacancy inside a graphene layer. It was found that the lithium atom is adsorbed on this vacancy, with a binding energy much larger than the lithium cohesive energy. Then, the adsorption of hydrogen molecules around lithium atoms was studied. We found that at 300 K and atmospheric pressure, this system could store up to 6.2 wt.% hydrogen, with average adsorption energy of 0.19 eV per molecule. Thus, this material satisfies the gravimetric capacity requirements for technological applications. A complete desorption of hydrogen occurs at 750 K. However, a multilayer of this system would be required for practical reasons. Under atmospheric pressure and at 300 K, we found that a system made of multiple layers of this material is stable. The storage capacity remained at 6.2 wt.%, but all adsorbed molecules were dissociated. The average adsorption energy becomes 0.875 eV/H. [Copyright &y& Elsevier]

Abstract: Using density functional theory and molecular dynamics to explore the adsorption of CO2 and CH4 at atmospheric pressure and 300K we found that both adsorb on a graphene layer modified with titanium at high metal coverage (C2Ti). The first dissociates to CO and O when adsorbed. The second is not dissociated and desorbs at 600K. [Copyright &y& Elsevier]

Abstract: The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac)2 and NaBPh4 in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral NiII centres with trans-Ni2N2O4 chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni–O(aquo)–N bond angle is 137.65(17)°. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature. [Copyright &y& Elsevier]

Simultaneous pancreas/kidney transplants require a long graft survival and the recipient to present with more benefits than risks. We evaluated the risk factors of receptor's death and pancreatic graft loss on 2 occasions (3 and 12 months' postoperatively) in 292 transplants in whom 22 variables were evaluated. Variables were selected, 9 receivers, 8 donors, and 5 variables related to the surgical procedure. All independent variables were compared with the dependent variables of pancreatic graft losses and patient deaths. Those considered significant according to univariate analysis were analyzed by using multiple logistic regression techniques in an attempt to develop a mathematical model capable of predicting both pancreatic graft and patient losses. Lastly, based on the resulting models with all significant variables, scores were created to determine the risk of patient death and pancreatic graft loss. In the adjusted multivariate analysis, the significant variables were donor age, receiver's body mass index, initial pancreas implant, iliac venous drainage, and use of induction therapy related to pancreatic loss within 3 months after transplantation. Independent risk factors regarding the loss of patients within 12 months were body mass index and receptor induction therapy. The variables related to pancreatic graft loss within 3 months were donor age, receiver body mass index, initial use of pancreatic graft, iliac venous drainage, and induction therapy; these variables can be used for creating a risk score. The donor body mass index and the induction therapy were independently related to patient loss within 12 months after the transplant. [ABSTRACT FROM AUTHOR]

The San Lorenzo Tezonco deep well, drilled in 2012 by “Sistema de Aguas de la Ciudad de México” (Water Supply System of Mexico City) in the Mexico Basin to a depth of 2008m, offers an excellent opportunity to explore the subsurface stratigraphy and general geology of the region. Unfortunately, only chipped samples from this well were recovered, which were examined and analyzed for whole-rock chemistry, 40Ar/39Ar, and U–Pb zircon geochronology, in order to reconstruct the lithology of the well. Contrary to previous deep wells of the Mexico Basin, no basement sedimentary rocks were found in this one. While the upper 70m are composed of lacustrine sediments associated with Lake Texcoco, volcanic rocks make up the majority of the well and range in age from more than 18Ma to 0.25Ma. Andesitic lavas are the most abundant products of the stratigraphic column, followed by acidic products represented by dacitic and rhyolitic lavas and ignimbrite deposits. Less abundant are basaltic andesite lavas appearing in the upper and lower parts of the column. The thickest sequence of the well is represented not only by Miocene volcanic rocks ranging from 5 to 17Ma, suggesting a period of intense volcanic activity in this area producing mainly andesitic lavas, but also by thick rhyolitic ignimbrite deposits dated at 5Ma. These deposits suggest the presence of a caldera structure, probably buried by subsequent volcanic products and lacustrine sediments. Trace element concentrations suggest that volcanism is likely produced in a subduction environment with typical negative anomalies of Nb, Ta, Ti, and P and positive anomalies in Pb and Cs. We correlated the well units with units outcropping in mountain ranges in the surrounding area, with the recognition of the following units or formations: Eocene Andesite, San Nicolás Basaltic Andesite, Tepoztlán Formation, Miocene Volcanism, Sierra de las Cruces, and Chichinautzin Volcanic Field products. By correlating the two closest deep wells (Mixhuca and Tulyehualco) we conclude that the San Lorenzo Tezonco well is located in a graben-like structure hosting the Santa Catarina volcanic range. [ABSTRACT FROM AUTHOR]

• In this article we propose a stochastic extension of the Jones et al. model for the spatial distribution of home burglary. • The stochastic model includes the fact that a proportion of burglars is willing to make long trips to burgle faraway homes. • Trips to distant targets are modeled by long-range jumps following a random motion, which is biased by the attractiveness field. • The stochastic model allows the formation of central hotspots, these kinds of hotspots are seen in burglary data in urban zones. • Our Stochastic with long-range jumps model are applied to three different scenarios in Mexico City. Mathematical models for predicting the geographical distribution of areas with high rates of home burglary and numerical experiments to evaluate the effectiveness of police patrol routing strategies in reducing crime can support security policymakers in planning more effective patrol routes. We give an overview of the model formulated by Jones et al. (2010) to study the effects of the presence of law enforcement on the formation of home-burglary hotspots. We propose an extension of the model to contemplate that a small proportion of burglars travel far away from their awareness space to burgle houses. We incorporate these trips in the form of long-range stochastic jumps that are biased towards more attractive sites. Simulations suggest that hotspots lose attractiveness as police more influences via deterrence on burglars' decision making about returning home rather than burglarizing a house. The results indicate that a higher proportion of burglars making long crime journeys might counteract the deterrent effect form the police presence. A case study is carried out to predict at the zone and citywide levels the distribution of areas with the highest home burglary rates in Mexico City. The L-BFGS method is applied to get the values for the parameters in both the Jones et al. model and our model; we use data from home burglaries reported, patrol zones and prison admissions. The minimum of the objective function is slightly lower for our model than for the Jones et al. model. Results obtained through numerical simulations using our model better fit the spatial statistical distribution of home-burglary hotspots for the entire city than for the zones. [ABSTRACT FROM AUTHOR]

Abstract: Background: Simultaneous pancreas-kidney transplantation has evolved as the best treatment for type 1 diabetic patients at end-stage renal disease. The surgical complication rate is high, which is an important barrier to the success of this procedure. The frequent complications that require relaparotomies include fistulas, graft thromboses, and intra-abdominal abscesses. Intestinal obstructions after pancreas transplantation due to internal herniation are not common. Purpose: The objective of this article was to review the literature about this problem and describe our personal experience in pancreas transplantation. Methods: We examined the cases of small bowel obstruction secondary to an internal hernia after following 292 pancreas transplantations in our center from 2000 to 2009 as well as performed a Medline literature review. Results: Only 2 articles described the diagnosis and treatment of internal hernias after pancreas transplantation. However, both contribution were from the same center reporting the same 3 cases, with surgical versus radiologic perspectives. We have described our 2 cases of young pancreas-kidney transplant patients who presented with acute intestinal obstruction due to internal hernia. Conclusion: Although internal hernias are rare, they are potentially fatal and difficult to diagnose when they occur after pancreas transplantation. Detection with early surgery demands a high degree of clinical vigilance. [ABSTRACT FROM AUTHOR]

Abstract: Simultaneous pancreas-kidney transplantation (SPKT) has been accepted as treatment for type I diabetic patients with end-stage renal disease. Its success depends largely on the surgical technique. This study sought to compare groups of SPKT with initial pancreas implantation versus initial kidney implantation. From December 2000 to September 2006, 151 SPKT were performed by a single center. In 85 cases, the pancreas was implanted first (group 1), and in 66 cases the order was inverted (group 2). Variables were implantation sequence, pancreas and kidney ischemia time, donor age, venous drainage, previous donor peritoneal dialysis, and recipient age and gender. Outcome variables included pancreas vascular thrombosis, 3-month graft survival, 3-month patient survival, pancreas rejection episodes, intra-abdominal infection, diabetes control and reoperations. We observed a 10.6% incidence of vascular thrombosis in group 1 but none in group 2 (P = .005). In groups 1 and 2, the 3-month pancreas survivals were 74.1% and 89.4% (P = .022), and the mean hospital stays were 24.3 and 15.8 days, respectively (P = .002). Our results suggested that, when 2 different teams are involved in SPKT, with >1 exposure and the need for retractor replacement, the kidney should be transplanted first, because the pancreas may be damaged during the surgical procedure. [Copyright &y& Elsevier]