Predicting polarization enhancement in multicomponent ferroelectric superlattices

Ab initio calculations are utilized as an input to develop a simple model of polarization in epitaxial short-period CaTiO3/SrTiO3/BaTiO3 superlattices grown on a SrTiO3 substrate. The model is then combined with a genetic algorithm technique to optimize the arrangement of individual CaTiO3, SrTiO3 and BaTiO3 layers in a superlattice, predicting structures with the highest possible polarization and a low in-plane lattice constant mismatch with the substrate. This modelling procedure can be applied to a wide range of layered perovskite-oxide nanostructures providing guidance for experimental development of nanoelectromechanical devices with substantially improved polar properties.Comment: 4 pages, submitted to PR

Temperature Changes in the United States

Temperature is among the most important climatic elements used in decision-making. For example, builders and insurers use temperature data for planning and risk management while energy companies and regulators use temperature data to predict demand and set utility rates. Temperature is also a key indicator of climate change: recent increases are apparent over the land, ocean, and troposphere, and substantial changes are expected for this century. This chapter summarizes the major observed and projected changes in near-surface air temperature over the United States, emphasizing new data sets and model projections since the Third National Climate Assessment (NCA3). Changes are depicted using a spectrum of observations, including surface weather stations, moored ocean buoys, polar-orbiting satellites, and temperature-sensitive proxies. Projections are based on global models and downscaled products from CMIP5 (Coupled Model Intercomparison Project Phase 5) using a suite of Representative Concentration Pathways (RCPs; see Ch. 4: Projections for more on RCPs and future scenarios)

A matter of divergence: Tracking recent warming at hemispheric scales using tree ring data

No current tree ring (TR) based reconstruction of extratropical Northern Hemisphere (ENH) temperatures that extends into the 1990s captures the full range of late 20th century warming observed in the instrumental record. Over recent decades, a divergence between cooler reconstructed and warmer instrumental large-scale temperatures is observed. We hypothesize that this problem is partly related to the fact that some of the constituent chronologies used for previous reconstructions show divergence against local temperatures in the recent period. In this study, we compiled TR data and published local/regional reconstructions that show no divergence against local temperatures. These data have not been included in other large-scale temperature reconstructions. Utilizing this data set, we developed a new, completely independent reconstruction of ENH annual temperatures (1750–2000). This record is not meant to replace existing reconstructions but allows some degree of independent validation of these earlier studies as well as demonstrating that TR data can better model recent warming at large scales when careful selection of constituent chronologies is made at the local scale. Although the new series tracks the increase in ENH annual temperatures over the last few decades better than any existing reconstruction, it still slightly under predicts values in the post-1988 period. We finally discuss possible reasons why it is so difficult to model post-mid-1980s warming, provide some possible alternative approaches with regards to the instrumental target and detail several recommendations that should be followed in future large-scale reconstruction attempts that may result in more robust temperature estimates

Genetic algorithm dynamics on a rugged landscape

The genetic algorithm is an optimization procedure motivated by biological evolution and is successfully applied to optimization problems in different areas. A statistical mechanics model for its dynamics is proposed based on the parent-child fitness correlation of the genetic operators, making it applicable to general fitness landscapes. It is compared to a recent model based on a maximum entropy ansatz. Finally it is applied to modeling the dynamics of a genetic algorithm on the rugged fitness landscape of the NK model.Comment: 10 pages RevTeX, 4 figures PostScrip

Phase I/II Study of Bortezomib-BEAM and Autologous Hematopoietic Stem Cell Transplantation for Relapsed Indolent Non-Hodgkin Lymphoma, Transformed, or Mantle Cell Lymphoma

AbstractA phase I/II trial was designed to evaluate the safety and efficacy of adding bortezomib to standard BEAM (BCNU, etoposide, cytarabine, melphalan) and autologous hematopoietic stem cell transplantation (ASCT). Eligible patients had relapsed/refractory indolent or transformed non-Hodgkin lymphoma or mantle cell lymphoma (MCL) that was relapsed/refractory or in first partial (PR) or complete remission (CR). Patients received bortezomib on days −11, −8, −5, and −2 before ASCT. Phase I had 4 dose cohorts (.8, 1, 1.3, and 1.5 mg/m2) and 3 patients were accrued to each. Any nonhematological ASCT-related toxicity >2 on the Bearman scale occurring between day −11 and engraftment defined the maximum tolerated dose (MTD). After the MTD has been reached, another 20 patients were enrolled at this dose to determine a preliminary overall response rate (ORR). Patients who were in CR or PR at day +100 were considered responders. The study enrolled 42 patients through August 14, 2009. The median age was 58 (range, 34 to 73) years, with 33 males and 9 females. The most common diagnoses were MCL (23 patients) and follicular lymphoma (7 patients). The median number of prior therapies was 1 (range, 0 to 6). The median follow-up was 4.88 (range, 1.07 to 6.98) years. Thirteen patients were treated in phase I and 29 patients were treated in phase II. The MTD was initially determined to be 1.5 mg/m2 but it was later decreased to 1 mg/m2 because of excessive gastrointestinal toxicity and peripheral neuropathy. The ORR was 95% at 100 days and 87% at 1 year. For all 38 evaluable patients at 1 year, responses were CR 84%, PR 1%, and progressive disease 13%. Progression-free survival (PFS) was 83% (95% CI, 68% to 92%) at 1 year, and 32% (15% to 51%) at 5 years. Overall survival (OS) was 91% (95% CI, 79% to 96%) at 1 year and 67% (50% to 79%) at 5 years. The most common National Cancer Institute grade 3 toxicities were neutropenic fever (59%), anorexia (21%), peripheral neuropathy (19%), orthostatic hypotension/vasovagal syncope (16%), and 1 patient failed to engraft. Compared with 26 MCL in CR1 historic controls treated with BEAM and ASCT, PFS was 85% and 43% for the BEAM group versus 87% and 57% for those who received bortezomib in addition to standard BEAM (V-BEAM) at 1 and 5 years, respectively (log-rank P = .37). OS was 88% and 50% for the BEAM group versus 96% and 72% for V-BEAM at 1 and 5 years, respectively (log-rank P = .78). In conclusion, V-BEAM and ASCT is feasible. The toxicities were manageable and we did not observe any treatment-related mortalities; however, we did observe an excess of autonomic dysfunction and ileus, which is concerning for overlapping toxicity with BEAM conditioning. Determining relative efficacy of V-BEAM compared to BEAM would require a randomized trial

The global precipitation response to volcanic eruptions in the CMIP5 models

We examine the precipitation response to volcanic eruptions in the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations compared to three observational datasets, including one with ocean coverage. Global precipitation decreases significantly following eruptions in CMIP5 models, with the largest decrease in wet tropical regions. This also occurs in observational land data, and ocean data in the boreal cold season. Monsoon rainfall decreases following eruptions in both models and observations. In response to individual eruptions, the ITCZ shifts away from the hemisphere with the greater concentration of aerosols in CMIP5. Models undergo a longer-lasting ocean precipitation response than over land, but the response in the short satellite record is too noisy to confirm this. We detect the influence of volcanism on precipitation in all three datasets in the cold season, although the models underestimate the size of the response. In the warm season the volcanic influence is only marginally detectable

T-cell project: an international, longitudinal, observational study of patients with aggressive peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of neoplasms that are derived from post-thymic lymphoid cells at different stages of differentiation and with different morphological patterns, phenotypes, and clinical presentations. PTCLs are highly diverse, reflecting the diverse cells from which they can originate and are currently sub-classified using World Health Organization (WHO) 2008 criteria. Peripheral T-Cell Lymphomas account for 5%-10% of all lymphoproliferative disorders in the Western hemisphere, with an overall incidence of 0.5-2 per 100,000 individuals per year, and have a striking epidemiological distribution, with higher incidence in Asia. The clinical features of PTCL are extremely heterogeneous. PTCLs express even more clinical diversity than B-cell non-Hodgkin's lymphomas, and there is a close, though not absolute, relationship between some unusual clinical features and certain histological subtypes

Transmission routes of rare seasonal diseases: the case of norovirus infections

Norovirus (NoV) is the most commonly recognized cause of acute gastroenteritis, with over a million cases globally per year. While usually self-limiting, NoV poses a substantial economic burden because it is highly contagious and there are multiple transmission routes. Infection occurs through inhalation of vomitus; faecal-oral spread; and food, water and environmental contamination. While the incidence of the disease is predictably seasonal, much less is known about the relative contribution of the various exposure pathways in causing disease. Additionally, asymptomatic excretion and viral shedding make forecasting disease burden difficult. We develop a novel stochastic dynamic network model to investigate the contributions of different transmission pathways in multiple coupled social networks representing schools, hospitals, care-homes and family households in a community setting. We analyse how the networks impact on transmission. We used ward-level demographic data from Northumberland, UK to create a simulation cohort. We compared the results with extant data on NoV cases from the IID2 study. Connectivity across the simulated cohort was high. Cases of NoV showed marked seasonality, peaking in early winter and declining through the summer. For the first time, we show that fomites and food appear to be the most important exposure routes in determining the population burden of disease. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’. This theme issue is linked with the earlier issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’