Characterizing normal crossing hypersurfaces

The objective of this article is to give an effective algebraic characterization of normal crossing hypersurfaces in complex manifolds. It is shown that a hypersurface has normal crossings if and only if it is a free divisor, has a radical Jacobian ideal and a smooth normalization. Using K. Saito's theory of free divisors, also a characterization in terms of logarithmic differential forms and vector fields is found and and finally another one in terms of the logarithmic residue using recent results of M. Granger and M. Schulze.Comment: v2: typos fixed, final version to appear in Math. Ann.; 24 pages, 2 figure

Iron oxidation at low temperature (260–500 C) in air and the effect of water vapor

The oxidation of iron has been studied at low temperatures (between 260 and 500 C) in dry air or air with 2 vol% H2O, in the framework of research on dry corrosion of nuclear waste containers during long-term interim storage. Pure iron is regarded as a model material for low-alloyed steel. Oxidation tests were performed in a thermobalance (up to 250 h) or in a laboratory furnace (up to 1000 h). The oxide scales formed were characterized using SEM-EDX, TEM, XRD, SIMS and EBSD techniques. The parabolic rate constants deduced from microbalance experiments were found to be in good agreement with the few existing values of the literature. The presence of water vapor in air was found to strongly influence the transitory stages of the kinetics. The entire structure of the oxide scale was composed of an internal duplex magnetite scale made of columnar grains and an external hematite scale made of equiaxed grains. 18O tracer experiments performed at 400 C allowed to propose a growth mechanism of the scale

Managing healthcare budgets in times of austerity: the role of program budgeting and marginal analysis

Given limited resources, priority setting or choice making will remain a reality at all levels of publicly funded healthcare across countries for many years to come. The pressures may well be even more acute as the impact of the economic crisis of 2008 continues to play out but, even as economies begin to turn around, resources within healthcare will be limited, thus some form of rationing will be required. Over the last few decades, research on healthcare priority setting has focused on methods of implementation as well as on the development of approaches related to fairness and legitimacy and on more technical aspects of decision making including the use of multi-criteria decision analysis. Recently, research has led to better understanding of evaluating priority setting activity including defining ‘success’ and articulating key elements for high performance. This body of research, however, often goes untapped by those charged with making challenging decisions and as such, in line with prevailing public sector incentives, decisions are often reliant on historical allocation patterns and/or political negotiation. These archaic and ineffective approaches not only lead to poor decisions in terms of value for money but further do not reflect basic ethical conditions that can lead to fairness in the decision-making process. The purpose of this paper is to outline a comprehensive approach to priority setting and resource allocation that has been used in different contexts across countries. This will provide decision makers with a single point of access for a basic understanding of relevant tools when faced with having to make difficult decisions about what healthcare services to fund and what not to fund. The paper also addresses several key issues related to priority setting including how health technology assessments can be used, how performance can be improved at a practical level, and what ongoing resource management practice should look like. In terms of future research, one of the most important areas of priority setting that needs further attention is how best to engage public members

Microenvironmental immune cell alterations across the spectrum of nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B-cell lymphoma

BACKGROUND: The clinicopathological spectrum of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), also known as nodular lymphocyte predominant B-cell lymphoma, partially overlaps with T-cell/histiocyte-rich large B-cell lymphoma (THRLCBL). NLPHL histology may vary in architecture and B-cell/T-cell composition of the tumour microenvironment. However, the immune cell phenotypes accompanying different histological patterns remain poorly characterised. METHODS: We applied a multiplexed immunofluorescence workflow to identify differential expansion/depletion of multiple microenvironmental immune cell phenotypes between cases of NLPHL showing different histological patterns (as described by Fan et al, 2003) and cases of THRLBCL. RESULTS: FOXP3-expressing T-regulatory cells were conspicuously depleted across all NLPHL cases. As histology progressed to variant Fan patterns C and E of NLPHL and to THRLBCL, there were progressive expansions of cytotoxic granzyme-B-expressing natural killer and CD8-positive T-cells, PD1-expressing CD8-positive T-cells, and CD163-positive macrophages including a PDL1-expressing subset. These occurred in parallel to depletion of NKG2A-expressing natural killer and CD8-positive T-cells. DISCUSSION: These findings provide new insights on the immunoregulatory mechanisms involved in NLPHL and THLRBCL pathogenesis, and are supportive of an increasingly proposed biological continuum between these two lymphomas. Additionally, the findings may help establish new biomarkers of high-risk disease, which could support a novel therapeutic program of immune checkpoint interruption targeting the PD1:PDL1 and/or NKG2A:HLA-E axes in the management of high-risk NLPHL and THRLBCL

The impact of consent on observational research: a comparison of outcomes from consenters and non consenters to an observational study

Background Public health benefits from research often rely on the use of data from personal medical records. When neither patient consent nor anonymisation is possible, the case for accessing such records for research purposes depends on an assessment of the probabilities of public benefit and individual harm. Methods In the late 1990s, we carried out an observational study which compared the care given to affluent and deprived women with breast cancer. Patient consent was not required at that time for review of medical records, but was obtained later in the process prior to participation in the questionnaire study. We have re-analysed our original results to compare the whole sample with those who later provided consent. Results Two important findings emerged from the re-analysis of our data which if presented initially would have resulted in insufficient and inaccurate reporting. Firstly, the reduced dataset contains no information about women presenting with locally advanced or metastatic cancer and we would have been unable to demonstrate one of our initial key findings: namely a larger number of such women in the deprived group. Secondly, our re-analysis of the consented women shows that significantly more women from deprived areas (51 v 31%, p = 0.018) received radiotherapy compared to women from more affluent areas. Previously published data from the entire sample demonstrated no difference in radiotherapy treatment between the affluent and deprived groups. Conclusion The risk benefit assessment made regarding the use of medical records without consent should include the benefits of obtaining research evidence based on 100% of the population and the possibility of inappropriate or insufficient findings if research is confined to consented populations

Tuneable photoconductivity and mobility enhancement in printed MoS 2 /graphene composites

This is the author accepted manuscript. The final version is available from IOP Publishing via the DOI in this record.With the aim of increasing carrier mobility in nanosheet-network devices, we have investigated MoS2–graphene composites as active regions in printed photodetectors. Combining liquid exfoliation and inkjet-printing, we fabricated all-printed photodetectors with graphene electrodes and MoS2–graphene composite channels with various graphene mass fractions (0  ≤  M f  ≤  16 wt%). The increase in channel dark conductivity with M f was consistent with percolation theory for composites below the percolation threshold. While the photoconductivity increased with graphene content, it did so more slowly than the dark conductivity, such that the fractional photoconductivity decayed rapidly with increasing M f. We propose that both mobility and dark carrier density increase with graphene content according to percolation-like scaling laws, while photo-induced carrier density is essentially independent of graphene loading. This leads to percolation-like scaling laws for both photoconductivity and fractional photoconductivity—in excellent agreement with the data. These results imply that channel mobility and carrier density increase up to 100-fold with the addition of 16 wt% graphene.We acknowledge the Science Foundation Ireland (SFI/12/RC/2278), the European Commission (n° 696656, Graphene Flagship) and the European Research Council (FUTURE-PRINT)

A comparison of transient elastography with acoustic radiation force impulse elastography for the assessment of liver health in patients with chronic hepatitis C: Baseline results from the TRACER study

BACKGROUND: Liver stiffness measurements can be used to assess liver fibrosis and can be acquired by transient elastography using FibroScan® and with Acoustic Radiation Force Impulse imaging. The study aimed to establish liver stiffness measurement scores using FibroScan® and Acoustic Radiation Force Impulse in a chronic hepatitis C cohort and to explore the correlation and agreement between the scores and the factors influencing agreement. METHODS: Patients had liver stiffness measurements acquired with FibroScan® (right lobe of liver) and Acoustic Radiation Force Impulse (right and left lobe of liver). We used Spearman’s correlation to explore the relationship between FibroScan® and Acoustic Radiation Force Impulse scores. A Bland–Altman plot was used to evaluate bias between the mean percentage differences of FibroScan® and Acoustic Radiation Force Impulse scores. Univariable and multivariable analyses were used to assess how factors such as body mass index, age and gender influenced the agreement between liver stiffness measurements. RESULTS: Bland-Altman showed the average (95% CI) percentage difference between FibroScan® and Acoustic Radiation Force Impulse scores was 27.5% (17.8, 37.2), p < 0.001. There was a negative correlation between the average and percentage difference of the FibroScan® and Acoustic Radiation Force Impulse scores (r (95% CI) = −0.41 (−0.57, −0.21), p < 0.001), thus showing that percentage difference gets smaller for greater FibroScan® and Acoustic Radiation Force Impulse scores. Body mass index was the biggest influencing factor on differences between FibroScan® and Acoustic Radiation Force Impulse (r = 0.12 (0.01, 0.23), p = 0.05). Acoustic Radiation Force Impulse scores at segment 5/8 and the left lobe showed good correlation (r (95% CI) = 0.83 (0.75, 0.89), p < 0.001). CONCLUSION: FibroScan® and Acoustic Radiation Force Impulse had similar predictive values for the assessment of liver stiffness in patients with chronic hepatitis C infection; however, the level of agreement varied across lower and higher scores

Lorentz violating kinematics: Threshold theorems

Recent tentative experimental indications, and the subsequent theoretical speculations, regarding possible violations of Lorentz invariance have attracted a vast amount of attention. An important technical issue that considerably complicates detailed calculations in any such scenario, is that once one violates Lorentz invariance the analysis of thresholds in both scattering and decay processes becomes extremely subtle, with many new and naively unexpected effects. In the current article we develop several extremely general threshold theorems that depend only on the existence of some energy momentum relation E(p), eschewing even assumptions of isotropy or monotonicity. We shall argue that there are physically interesting situations where such a level of generality is called for, and that existing (partial) results in the literature make unnecessary technical assumptions. Even in this most general of settings, we show that at threshold all final state particles move with the same 3-velocity, while initial state particles must have 3-velocities parallel/anti-parallel to the final state particles. In contrast the various 3-momenta can behave in a complicated and counter-intuitive manner.Comment: V1: 32 pages, 6 figures, 3 tables. V2: 5 references adde

Physics of Neutron Star Kicks

It is no longer necessary to `sell' the idea of pulsar kicks, the notion that neutron stars receive a large velocity (a few hundred to a thousand km s$^{-1}$) at birth. However, the origin of the kicks remains mysterious. We review the physics of different kick mechanisms, including hydrodynamically driven, neutrino and magnetically driven kicks.Comment: 8 pages including 1 figure. To be published in "Stellar Astrophysics" (Pacific Rim Conference Proceedings), (Kluwer Pub.