LLukas22/scidocs huggingface dataset:
{PT}-Symmetric Quantum Electrodynamics---{PT}QED

The construction of PT -symmetric quantum electrodynamics is reviewed. In particular, the massless version of the theory in 1 + 1 dimensions (the Schwinger model) is solved. Difficulties with unitarity of the S-matrix are discussed. 1. PT QED Quantum electrodynamics (QED) is by far the most successful physical theory ever devised [1]. However, although its reach includes all of atomic physics, there are a myriad of phenomena that we do not understand. Thus it is essential to explore alternative theories, in the hope that we may be able to describe aspects of the world that are as yet not under our understanding. One very promising new approach to quantum theories are those included under the rubric of non-Hermitian theories, in particular theories in which invariance under the combined operation of space and time reflection PT replaces mathematical Dirac Hermiticity in order to guarantee unitarity of the theory. (For a recent review, see [2].) Little work, however, has been done on applying this idea to quantum field theory. This paper represents our continuing effort to develop a PT -symmetric version of quantum electrodynamics, in the hope that a consistent theory, with a unitary S-matrix, results that may eventually find physical applications in nature. 1.1. Transformation properties At the first International Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physics [3] a PT -symmetric version of quantum electrodynamics was proposed. A non-Hermitian but PT -symmetric electrodynamics is based on the assumption of novel transformation properties of the electromagnetic fields under parity P transformations, that is, P : E → E, B → −B, A → A, A → −A, (1) PT -Symmetric Quantum Electrodynamics—PT QED 2 just the statement that the four-vector potential is assumed to transform as an axial vector. Under time reversal T , the transformations are assumed to be conventional, T : E → E, B → −B, A → −A, A → A. (2) Fermion fields are also assumed to transform conventionally. We use the metric g = diag(−1, 1, 1, 1). 1.2. Lagrangian and Hamiltonian The Lagrangian of the theory then possesses an imaginary coupling constant in order that it be invariant under the product of these two symmetries: L = − 4 F Fμν − 1 2 ψγγ 1 i ∂μψ − m 2 ψγψ + i 2 ψγγeqψAμ. (3) Here, because we are discarding Hermiticity as a physical requirement, it is most appropriate to use a “real” field formulation, where correspondingly the (antisymmetric, imaginary) charge matrix q = σ2 appears. Furthermore, γ γ is symmetric and γ is antisymmetric. In the radiation (Coulomb) gauge ∇ · A = 0, the dynamical variables are A and ψ, and the canonical momenta are πA = −ET , πψ = i 2ψ, where T denotes the transverse part, and so the relation between the Hamiltonian and Lagrangian densities are H = E + E · ∇A + i 2 ψψ̇ − L. (4) Then, if integrate by parts and use ∇ · E = ij, we find that the corresponding Hamiltonian is H = ∫ (dr) { 1 2 (E + B) + 1 2 ψ [ γγ ( 1 i ∇k − ieqAk )
Measuring Neural Net Robustness with Constraints

Despite having high accuracy, neural nets have been shown to be susceptible to adversarial examples, where a small perturbation to an input can cause it to become mislabeled. We propose metrics for measuring the robustness of a neural net and devise a novel algorithm for approximating these metrics based on an encoding of robustness as a linear program. We show how our metrics can be used to evaluate the robustness of deep neural nets with experiments on the MNIST and CIFAR-10 datasets. Our algorithm generates more informative estimates of robustness metrics compared to estimates based on existing algorithms. Furthermore, we show how existing approaches to improving robustness “overfit” to adversarial examples generated using a specific algorithm. Finally, we show that our techniques can be used to additionally improve neural net robustness both according to the metrics that we propose, but also according to previously proposed metrics.
Transmission capacity of wireless ad hoc networks with outage constraints

In this paper, upper and lower bounds on the transmission capacity of spread-spectrum (SS) wireless ad hoc networks are derived. We define transmission capacity as the product of the maximum density of successful transmissions multiplied by their data rate, given an outage constraint. Assuming that the nodes are randomly distributed in space according to a Poisson point process, we derive upper and lower bounds for frequency hopping (FH-CDMA) and direct sequence (DS-CDMA) SS networks, which incorporate traditional modulation types (no spreading) as a special case. These bounds cleanly summarize how ad hoc network capacity is affected by the outage probability, spreading factor, transmission power, target signal-to-noise ratio (SNR), and other system parameters. Using these bounds, it can be shown that FH-CDMA obtains a higher transmission capacity than DS-CDMA on the order of M/sup 1-2//spl alpha//, where M is the spreading factor and /spl alpha/>2 is the path loss exponent. A tangential contribution is an (apparently) novel technique for obtaining tight bounds on tail probabilities of additive functionals of homogeneous Poisson point processes.
Do Institutions Matter for FDI Spillovers ? The Implications of China ’ s “ Special Characteristics ”

A number of recent studies examine the spillovers of foreign direct investment (FDI) on China‟s domestic industrial enterprises. This study goes further by investigating the implications of institutions for the nature of spillovers during 1998-2007. We examine three institutional features that comprise aspects of China‟s “special characteristics”: (1) the different sources of FDI, where FDI is nearly evenly divided between mostly Organization for Economic Co-operation and Development (OECD) countries and the region known as “Greater China”, consisting of Hong Kong, Taiwan, and Macau; (2) China‟s heterogeneous ownership structure, involving state(SOEs) and non-state owned (non-SOEs) enterprises; and (3) industrial promotion via tariffs or through tax holidays to foreign direct investment. We find positive and significant linkages to domestic firms via horizontal foreign investment, forward linkages (the contacts between foreign affiliates and their local clients in downstream sectors) and backward linkages (the contacts between foreign buyers and local suppliers). Our results suggest varied success with industrial promotion policies. Final goods tariffs as well as input tariffs are negatively associated with firm-level productivity. However, we find statistically significant evidence of stronger productivity spillovers associated with firms that received tax breaks, suggesting that tax holidays were more successful than tariffs as an instrument to promote productivity growth in China. 1 Ph.D. candidate, Department of Agricultural and Resource Economics, University of California, Berkeley, 310 Giannini Hall, #3310, Berkeley, 94720-3310. Email: luosha@berkeley.edu We would like to thank Justin Lin, Max Auffhammer, Jeremy Magruder, for their valuable comments. 2 World Bank, 1818 H Street, N.W. 20433 Email: aharrison2@worldbank.org
Epidemiology and mortality of burns at the Queen Elizabeth Central Hospital Blantyre, Malawi.

OBJECTIVES
To determine the most common causes, population most at risk and the pattern of mortality of burn injuries at the Queen Elizabeth Central Hospital, Blantyre, Malawi.


DESIGN
Retrospective cross sectional study.


SETTING
Burns Unit, Queen Elizabeth Central Hospital (QECH), Blantyre, Malawi.


SUBJECTS
One thousand eight hundred and twenty five case files of burn patients admitted to the QECH, Blantyre, between January 1994 and December 1999, involving 941 male and 884 female patients among whom 145 were epileptic.


MAIN OUTCOME MEASURE
Aetiology of burns and the population most at risk at the QECH, Blantyre.


RESULTS
More males (52%) than females (48%) suffered from burns during the six year study period. Children below age five (55%) were most at risk while 89% were below 30 years of age. Hot water (38%) was the most common cause of burns, but among epileptic patients, it was open fire (83%). While 71% of all inpatients had superficial burns (less than 10% TBSA) 22% had deep burns requiring grafting. Almost all the patients (98%) had multiple antibiotic therapy combined with topical application of silver sulfadiazine. Overall mortality was 12% but among the epileptic patients it was 16%.


CONCLUSION
Children under five years of age were the major victims of burn injuries in this study. There is, therefore, need to mount effective awareness campaigns in order to target the root causes of burns in children.
Quality of life is associated with physical activity and fitness in cystic fibrosis

BACKGROUND
Health-related and disease-specific quality of life (HRQoL) has been increasingly valued as relevant clinical parameter in cystic fibrosis (CF) clinical care and clinical trials. HRQoL measures should assess - among other domains - daily functioning from a patient's perspective. However, validation studies for the most frequently used HRQoL questionnaire in CF, the Cystic Fibrosis Questionnaire (CFQ), have not included measures of physical activity or fitness. The objective of this study was, therefore, to determine the cross-sectional and longitudinal relationships between HRQoL, physical activity and fitness in patients with CF.


METHODS
Baseline (n = 76) and 6-month follow-up data (n = 70) from patients with CF (age ≥12 years, FEV1 ≥35%) were analysed. Patients participated in two multi-centre exercise intervention studies with identical assessment methodology. Outcome variables included HRQoL (German revised multi-dimensional disease-specific CFQ (CFQ-R)), body composition, pulmonary function, physical activity, short-term muscle power, and aerobic fitness by peak oxygen uptake and aerobic power.


RESULTS
Peak oxygen uptake was positively related to 7 of 13 HRQoL scales cross-sectionally (r = 0.30-0.46). Muscle power (r = 0.25-0.32) and peak aerobic power (r = 0.24-0.35) were positively related to 4 scales each, and reported physical activity to 1 scale (r = 0.29). Changes in HRQoL-scores were directly and significantly related to changes in reported activity (r = 0.35-0.39), peak aerobic power (r = 0.31-0.34), and peak oxygen uptake (r = 0.26-0.37) in 3 scales each. Established associates of HRQoL such as FEV1 or body mass index correlated positively with fewer scales (all 0.24 < r < 0.55).


CONCLUSIONS
HRQoL was associated with physical fitness, especially aerobic fitness, and to a lesser extent with reported physical activity. These findings underline the importance of physical fitness for HRQoL in CF and provide an additional rationale for exercise testing in this population.


TRIAL REGISTRATION
ClinicalTrials.gov, NCT00231686.
Quantitative analysis of regional motion and thickening by gated myocardial perfusion SPECT: normal heterogeneity and criteria for abnormality.

UNLABELLED
Quantitation of regional myocardial function is valuable in patients with coronary artery disease. This study assessed normal heterogeneity and developed and validated normal limits for quantitative regional motion and thickening by gated myocardial perfusion SPECT.


METHODS
Patients underwent rest (201)Tl/exercise (99m)Tc-sestamibi gated SPECT. Reference values of motion and thickening for 20 myocardial segments were obtained in 105 patients with <5% likelihood of coronary disease (low-likelihood group). Criteria for abnormality of motion and thickening were defined for each segment, using receiver operator characteristic analysis, in 101 patients with coronary disease (training group). Semiquantitative visual interpretation was used as the gold standard. These criteria were prospectively validated in 100 patients (validation group). Criteria for grading motion and thickening abnormalities by severity levels were also defined and validated.


RESULTS
Normal thickening decreased substantially along the longitudinal axis of the left ventricle, from 69% +/- 13% at the apex to 25% +/- 11% at the basal segments, whereas normal motion varied within the same ventricular plane. Validation of the criteria for abnormality yielded high accuracy in the detection of motion abnormalities (sensitivity, 88%; specificity, 92%) and thickening abnormalities (sensitivity, 87%; specificity, 89%). Quantitative motion and thickening segmental scores showed good agreement with visual scores.


CONCLUSION
Normal regional myocardial contraction by gated myocardial perfusion SPECT is characterized by a substantial apex-to-base decline in thickening and by circumferential heterogeneity in endocardial motion. The assignment of segment-specific threshold values for defining motion and thickening abnormalities provided reasonably accurate identification and grading of regional myocardial dysfunction.
Equational Properties of Kleene Algebras of Relations with Conversion

Abstract We describe a set of equational axioms for the variety generated by all algebras of binary relations with operations of union, composition, conversion and reflexive-transitive closure and neutral elements 0 (the empty relation) and 1 (the identity relation).
Validation of the KDQOL-SFTM: A dialysis-targeted health measure

Background: In evaluations of dialysis therapy, an assessment of health-related quality of life (HRQOL) is often important. The aim of this study was to determine the basic psychometric properties, reliability and validity of the short form of the KDQOLTM i.e. the KDQOL-SFTM, a dialysis-targeted instrument, and to assess its ability to detect changes over time. Methods: In a prospective cohort study (Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), all new adult ESRD patients in 32 different Dutch centers were consecutively enrolled. Demographic, clinical and HRQOL data were obtained 3 and 12 months after the start of chronic dialysis therapy. Results: The reliability of the KDQOL-SFTM was supported by test results that were above the recommended minimal values. Validity of KDQOL-SFTM was confirmed by the hypothesized positive correlations of the overall health rating and renal function, and by the negative correlations between the number of comorbidities and dialysis dose. Moreover, dialysis-targeted dimensions were more sensitive in detecting relevant differences pertaining to kidney diseases than generic dimensions. The KDQOL-SFTM was able to detect clinical changes over time. Conclusions: The psychometric properties of the KDQOL-SFTM were good, and the different dialysis-targeted dimensions were informative with a high reliability and validity. These results support the application of the KDQOL-SFTM in studies evaluating dialysis therapy.
Where Does the Developing Brain Obtain Its Docosahexaenoic Acid? Relative Contributions of Dietary α-Linolenic Acid, Docosahexaenoic Acid, and Body Stores in the Developing Rat

Docosahexaenoic acid (DHA), a 22-carbon, highly unsaturated, n-3 fatty acid, is important for optimal nervous system function. In this study, designed to quantify how preformed dietary DHA regulates metabolic pathways in vivo, 8-d-old rat pups were divided into four groups and fed artificial rat milk diets. One group was fed formula with deuterium-labeled LNA (d5-LNA) as the only source of n-3 fatty acids, and a second group was fed formula that contained d5-LNA and unlabeled DHA. Two additional groups were dam-reared to permit analysis of fatty acyl pool sizes at postnatal days 8 and 28. The dams were fed a diet that contained 3% unlabeled LNA. DHA in brain and liver was analyzed. Our study demonstrated that preformed DHA in the diet markedly decreased the amount of biosynthesized DHA that accumulated in the brain and the liver. Surprisingly, ∼40% of the DHA that was newly acquired during this period in the “LNA” group was unlabeled. Because there were no unlabeled n-3 fatty acids in this diet, this DHA must have been derived from body stores of n-3 fatty acids. Thus, body stores can be a significant source of brain DHA in animals that are fed LNA as the only source of n-3 fatty acids.
Comparison of anatomic and non-anatomic hepatic resection for hepatocellular carcinoma.

BACKGROUND
The aim of the present study was to compare the prognostic impact of anatomic resection (AR) versus non-anatomic resection (NAR) on patient survival after resection of a single hepatocellular carcinoma (HCC).


METHODS
To control for confounding variable distributions, a 1-to-1 propensity score match was applied to compare the outcomes of AR and NAR. Among 710 patients with a primary, solitary HCC of <5.0 cm in diameter that was resectable by either AR or NAR from 2003 to 2007 in Japan and Korea, 355 patients underwent NAR and 355 underwent AR of at least one section with complete removal of the portal territory containing the tumor.


RESULTS
Overall survival (OS) was better in the AR than NAR group (hazard ratio 1.67, 95% confidence interval 1.28-2.19, P < 0.001) while disease-free survival showed no significant difference. Significantly fewer patients in the AR than NAR group developed intrahepatic HCC recurrence and multiple intrahepatic recurrences. Patients with poorly differentiated HCC who underwent AR had improved disease-free survival and OS.


CONCLUSIONS
Anatomic resection decreases the risk of tumor recurrence and improves OS in patients with a primary, solitary HCC of <5.0 cm in diameter.
Charles Taylor and the Future of Secularism

A review of Taylor, Charles. A Secular Age. Cambridge: Bellknap Press, 2007. HB. $39.95, ISBN 9780674026766
Fog Water and Ecosystem Function: Heterogeneity in a California

Fog is thought to influence ecological function in coastal forests worldwide, yet few data are available that illuminate the mechanisms underlying this influence. In a California redwood forest we mea
ResearchArticle A Broadband Circularly Polarized Stacked Probe-Fed Patch Antenna for UHF RFID Applications

A broadband circularly polarized stacked probe-fed antenna suitable for UHF RFID applications is presented and studied. The proposed antenna is fed by two probes which are connected to a hybrid coupler. Two parasitic patches are stacked above a primary probe-fed patch to enhance the bandwidth of the antenna. The optimized antenna prototype achieves gain of more than 6.5 dBic, axial ratio of less than 3.0 dB, and return loss of less than−15 dB over the UHF band of 820–980 MHz (17.7%). Parametric studies are carried out to demonstrate the effects of antenna geometry parameters on the performance. The proposed antenna can be a good candidate for UHF RFID applications.
Practical Option Pricing with Support Vector Regression and MART by

Support Vector Regression and MART by Ian I-En Choo Stanford University
Target of rapamycin signalling mediates the lifespan-extending effects of dietary restriction by essential amino acid alteration

Dietary restriction (DR), defined as a moderate reduction in food intake short of malnutrition, has been shown to extend healthy lifespan in a diverse range of organisms, from yeast to primates. Reduced signalling through the insulin/IGF-like (IIS) and Target of Rapamycin (TOR) signalling pathways also extend lifespan. InDrosophila melanogaster the lifespan benefits of DR can be reproduced by modulating only the essential amino acids in yeast based food. Here, we show that pharmacological downregulation of TOR signalling, but not reduced IIS, modulates the lifespan response to DR by amino acid alteration. Of the physiological responses flies exhibit upon DR, only increased body fat and decreased heat stress resistance phenotypes correlated with longevity via reduced TOR signalling. These data indicate that lowered dietary amino acids promote longevity via TOR, not by enhanced resistance to molecular damage, but through modified physiological conditions that favour fat accumulation.
Automatically selecting shots for action movie trailers

Movie trailers, or previews, are an important method of advertising movies. They are extensively shown before movies in cinemas, as well as on television and increasingly, over the Internet. Making a trailer is a creative process, in which a number of shots from a movie are selected in order to entice a viewer in to paying to see the full movie. Thus, the creation of these trailers is an integral part in the promotion of a movie. Action movies in particular rely on trailers as a form of advertising as it is possible to show short, exciting portions of an action movie, which are likely to appeal to the target audience. This paper presents an approach which automatically selects shots from action movies in order to assist in the creation of trailers. A set of audiovisual features are extracted that aim to model the characteristics of shots typically present in trailers, and a support vector machine is utilised in order to select the relevant shots. The approach taken is not particularly novel but the results show that the process may be used in order to ease the trailer creation process or to facilitate the creation of variable length, or personalised trailers.
Time trends in prevalence and severity of childhood asthma and allergies from 1995 to 2002 in France.

OBJECTIVE
To assess time trends in symptoms of asthma, allergic rhinitis and atopic eczema among adolescents in Languedoc Roussillon, France.


METHODS
Two cross-sectional surveys were conducted 7 years apart using the same protocol. School-based samples of 3383 participants in the 1995 survey and 1642 participants in the 2002 survey respectively were recruited.


RESULTS
There was a tendency towards stagnation in current symptoms of asthma, rhinoconjunctivitis and eczema. Indices related to lifetime diagnosis of asthma, hay fever and eczema increased. For all the conditions, indices of severity also showed a decrease in the 7-year study period.


CONCLUSIONS
Our study shows that symptoms of asthma, allergic rhinitis and eczema were stable, supporting the effectiveness of national asthma prevention and management guidelines for such diseases. The increase in indices related to lifetime diagnosis could be the result of increased public and professional awareness of the diseases and changes in diagnostic labelling in recent years.
De-noising by soft-thresholding

Donoho and Johnstone (1992a) proposed a method for reconstructing an unknown function f on [0; 1] from noisy data di = f(ti) + zi, i = 0; : : : ; n 1, ti = i=n, zi iid N(0; 1). The reconstruction f̂ n is de ned in the wavelet domain by translating all the empirical wavelet coe cients of d towards 0 by an amount p 2 log(n) = p n. We prove two results about that estimator. [Smooth]: With high probability f̂ n is at least as smooth as f , in any of a wide variety of smoothness measures. [Adapt]: The estimator comes nearly as close in mean square to f as any measurable estimator can come, uniformly over balls in each of two broad scales of smoothness classes. These two properties are unprecedented in several ways. Our proof of these results develops new facts about abstract statistical inference and its connection with an optimal recovery model.