bluuebunny/crossref_metadata_2025 huggingface dataset:
Influencia del conflicto armado en el aumento de la incidencia de VIH/sida en Colombia, durante el periodo 2002-2008
Authors: Nevardo Malagón Jeadran
Published: January 2020

Introducción. Hasta el año 2000, la prevalencia de VIH/sida en Colombia era de 0,4%. La intensificación del conflicto armado ha coincidido con un aumento en la incidencia del virus. El presente estudio está enfocado en determinar la existencia de un vínculo entre el aumento de las tasas de VIH/sida y el conflicto armado en el país de 2002 a 2008.Métodos. Se realizó un estudio descriptivo retrospectivo. La población de estudio fueron hombres y mujeres entre los 15 y 59 años, residentes en el territorio nacional, a los cuales se les diagnosticó infección por el virus de la inmunodeficiencia adquirida (VIH) durante el periodo 2002-2008. Las variables fueron seleccionadas del índice de riesgo de situación humanitaria. Los datos fueron analizados en tablas de análisis bivariado. Resultados. Durante el periodo en mención, se registraron 121.548 asesinatos, 3.451 actos terroristas, 2’894.306 desplazados internos y 356 masacres. El 60% de las manifestaciones violentas del conflicto ocurrió en 9 de los 33 departamentos de Colombia.Además, se reportaron 28.518 nuevos casos de VIH/sida. El 70% (17.862) de los casos estuvo concentrado en seis departamentos. El 66% (10) de los departamentos con las mayores cifras de violencia también resultaron ser los departamentos con un alto índice de desarrollo humano, mayor de 0,7. Los departamentos con un índice mayor de 0,75 tuvieron una incidencia de VIH mayor de 0,6%. Los departamentos con un índice menor de 0,75 reportaron una incidencia de VIH/sida menor de 0,6%.La incidencia de infección entre la población en condición de desplazamiento fue menor de 0,6%. La relación hombres/mujeres con el virus fue de 2,68:1,4.Conclusiones. La epidemia de Colombia ha mostrado una tendencia a expandirse, en particular, en regiones donde la transmisión por el contacto deheterosexuales es predominante y donde el conflicto armado tiene una mayor intensidad. El caso de los departamentos que mostraron altas cifras de violencia armada pero bajas tasas de incidencia de VIH/sida, merece un interés especialporque podrían ocultar una enorme cantidad de subdiagnóstico, que saldría a luz en el caso de un acuerdo de paz entre el Estado y los grupos armados.
Análisis del miembro superior al tocar piano
Authors: Aldana Bitar Jairo Alejandro
Published: January 2020

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Displasias esqueléticas y factores de riesgo asociados. Descripción de 29 casos reportados en seis hospitales de Bogotá, Cali y Manizales
Authors: Rodríguez Guevara Fernando , Rueda Jaime Lili Johana , Zarante Montoya Ignacio Manuel
Published: January 2020

Objetivo. Hacer un análisis de los posibles factores de riesgo a partir de una serie de casos de displasias esqueléticas que se han reportado en los últimos ocho años en algunas ciudades de Colombia.Métodos. Se desarrolló un estudio de casos y controles en seis hospitales de tres ciudades (Cali, Manizales y Bogotá) que participan en el Estudio Colaborativo Latinoamericano de Malformaciones Congénitas. Para el análisis se incluyeron 29 casos y 85 controles.Resultados. Respecto a las variables cuantitativas, se encontraron diferencias estadísticamente significativas entre ambos grupos para edad paterna, edad de gestación, número de gestaciones y peso al nacer. Para las variables cualitativas, los casos presentaron un riesgo mayor de tener un peso menor de 2.500 g al nacer y un bajo peso para la edad de gestación.Conclusiones. Las displasias esqueléticas son una malformación poco frecuente en la población estudiada. En más de la mitad de los casos no se hace un diagnóstico específico. Esta malformación se asocia en esta muestra con avanzada edad paterna, bajo peso al nacer, edad de gestación y número de gestaciones.
Toward ultrafast, ultra-stable imaging arrays: Superlattice doping to enhance the performance of backside-illuminated 3D-hybridized silicon photodetectors
Authors: Jewell April D. , Looker Quinn , Sanchez Marcos O. , Nikzad Shouleh , Hoenk Michael E.
Published: January 2020

In this paper, the authors report the latest results on their development of superlattice-doped, thinned, backside-illuminated (BSI), 3D-integrated photodiode detectors—a step toward their ultimate goal of demonstrating ultrafast, ultrastable CMOS imaging arrays. As with most silicon-based photodetectors, backside-illumination and backside surface passivation are keys to achieve the highest performance capability. The two-dimensional (2D) doping technique developed at the Jet Propulsion Laboratory (JPL) has proved to result in a highly efficient, highly stable detector response when combined with a variety of detectors. Here, JPL's 2D-doping has been combined with Sandia's BSI photodetectors hybridized with custom fanout wafer via copper Direct Bond Interconnect (DBI®), a technology that is rapidly becoming industry standard for BSI CMOS imaging arrays. The prototype detectors were packaged and evaluated with respect to their response to low energy electrons. The authors find that the responsivity of 2D-doped BSI detectors is higher than devices prepared using other surface passivation techniques (i.e., ion implantation). The success of the work described herein verifies that the 2D-doping processes previously developed for Sandia's frontside-illuminated photodetectors are generally applicable to BSI detectors and demonstrates for the first time that JPL's 2D-doping process is compatible with the Cu-DBI® technology.
A performance comparison of tonal detectors for low-frequency vocalizations of Antarctic blue whales
Authors: Bouffaut Léa , Madhusudhana Shyam , Labat Valérie , Boudraa Abdel-Ouahab , Klinck Holger
Published: January 2020

Extraction of tonal signals embedded in background noise is a crucial step before classification and separation of low-frequency sounds of baleen whales. This work reports results of comparing five tonal detectors, namely the instantaneous frequency estimator, YIN estimator, harmonic product spectrum, cost-function-based detector, and ridge detector. Comparisons, based on a low-frequency adaptation of the Silbido scoring feature, employ five metrics, which quantify the effectiveness of these detectors to retrieve tonal signals that have a wide range of signal to noise ratios (SNRs) and the quality of the detection results. Ground-truth data were generated by embedding 20 synthetic Antarctic blue whale (Balaenoptera musculus intermedia) calls in randomly extracted 30-min noise segments from a 79 h-library recorded by an Ocean Bottom Seismometer in the Indian Ocean during 2012–2013. Monte-Carlo simulations were performed using 20 trials per SNR, ranging from 0 dB to 15 dB. Overall, the tonal detection results show the superiority of the cost-function-based and the ridge detectors, over the other detectors, for all SNR values. More particularly, for lower SNRs (⩽3 dB), these two methods outperformed the other three with high recall, low fragmentation, and high coverage scores. For SNRs ⩾7 dB, the five methods performed similarly.
Viable but Nonculturable Escherichia coli O157:H7 and Salmonella enterica in Fresh Produce: Rapid Determination by Loop-Mediated Isothermal Amplification Coupled with a Propidium Monoazide Treatment
Authors: Han Lu , Wang Kaidi , Ma Lina , Delaquis Pascal , Bach Susan , Feng Jinsong , Lu Xiaonan
Published: January 2020

VBNC pathogenic bacteria pose a potential risk to the food industry because they do not multiply on routine microbiological media and thus can evade detection in conventional plating assays. Both
E. coli
O157:H7 and
S. enterica
have been reported to enter the VBNC state under a range of environmental stress conditions and to resuscitate under favorable conditions and are a potential cause of human infections. PMA-LAMP methods developed in this study provide a rapid, sensitive, and specific way to determine levels of VBNC
E. coli
O157:H7 and
S. enterica
in fresh produce, which potentially decreases the risks related to the consumption of fresh produce contaminated by enteric pathogens in this state. PMA-LAMP can be further applied in the field study to enhance our understanding of the fate of VBNC pathogens in the preharvest and postharvest stages of fresh produce.
Influence of Substrate Concentration on the Culturability of Heterotrophic Soil Microbes Isolated by High-Throughput Dilution-to-Extinction Cultivation
Authors: Bartelme Ryan P. , Custer Joy M. , Dupont Christopher L. , Espinoza Josh L. , Torralba Manolito , Khalili Banafshe , Carini Paul
Published: January 2020

Isolating environmental microbes and studying their physiology under controlled conditions are essential aspects of understanding their ecology. Subsurface ecosystems are typically nutrient-poor environments that harbor diverse microbial communities—the majority of which are thus far uncultured. In this study, we use modified high-throughput cultivation methods to isolate subsurface soil microbes. We show that a component of whether a microbe is culturable from subsurface soils is the concentration of growth substrates in the culture medium. Our results offer new insight into technical approaches and growth medium design that can be used to access the uncultured diversity of soil microbes.
Health status, heat preparation strategies and medical events among elite cyclists who competed in the heat at the 2016 UCI Road World Cycling Championships in Qatar
Authors: Racinais Sebastien , Nichols David , Travers Gavin , Moussay Sebastien , Belfekih Taoufik , Farooq Abdulaziz , Schumacher Yorck Olaf , Périard Julien D
Published: January 2020

Purpose

Assess the health status and heat preparation strategies of athletes competing in a World Cycling Championships held in hot ambient conditions (37°C, 25% relative humidity, wet-bulb-globe-temperature 27°C) and monitor the medical events arising during competition.

Methods

69 cyclists (~9% of the world championships participants) completed a pre-competition questionnaire. Illnesses and injuries encountered by the Athlete Medical Centre (AMC) were extracted from the race reports.

Results

22% of respondents reported illness symptoms in the 10 days preceding the Championships. 57% of respondents had previously experienced heat-related symptoms (cramping most commonly) while 17% had previously been diagnosed with exertional heat illness. 61% of the respondents had undergone some form of heat exposure prior to the Championships, with 38% acclimating for 5 to 30 days. In addition, several respondents declared to live in warm countries and all arrived in Qatar ~5 days prior to their event. 96% of the respondents used a pre-cooling strategy for the time trials and 74% did so before the road race (p<0.001), with ice vests being the most common. The AMC assessed 46 injuries and 26 illnesses in total, with three cyclists diagnosed with heat exhaustion.

Conclusions

The prevalence of previous heat illness in elite cyclists calls for team and event organisation doctors to be trained on heat illness management, including early diagnosis and rapid on-site cooling. Some cyclists had been exposed to the heat prior to the Championships, but few had a dedicated plan, calling for additional education on the importance of heat acclimation. Pre-cooling was widely adopted.
Central themes, core concepts and knowledge gaps concerning social media use, and mental health and well-being among adolescents: a protocol of a scoping review of published literature
Authors: Schønning Viktor , Aarø Leif Edvard , Skogen Jens Christoffer
Published: January 2020

Introduction

The use of social media has risen steadily since its introduction in the early 2000s, and today there are between 2 and 3 billion users worldwide. Research on the link between use of social media and mental health has resulted in a vast number of studies covering diverse aspects of the link between them. The existing body of knowledge on use of social media, and mental health and well-being among adolescents is complex and difficult to follow. In this paper, we present a protocol for a scoping review to systematically identify and summarise the central research foci and knowledge gaps in the research field of social media use, and mental health and well-being among adolescents.

Methods and analysis

The current scoping review will adhere to the Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Reviews. The first step is to search relevant databases for eligible studies. Relevant databases are CINAHL, Ovid Medline, Embase, PsycINFO, Sociological Abstracts, Sociological Services Abstracts, ERIC, Cochrane Database of Systematic Reviews, CRD (Database of Abstracts of Reviews of Effects), NHS EED, HTA and Epistemonikos. Next, two reviewers from the research team will independently screen the identified studies for eligibility. Data extraction and data synthesis will be performed and result in summarised themes based on the findings.

Ethics and dissemination

A scoping review can be described as a method of gaining an overview and understanding of a research area, with its strengths and weaknesses, and as it involves peer-reviewed and published articles, a scoping review does not require ethical approval. We expect that the results from the current scoping review will produce a consolidated overview of existing studies and research gaps, and gather this knowledge into a coherent review. The results will be disseminated through relevant journals and conferences.
Are patients afraid to go home? Disposition preferences after transient ischaemic attack and minor stroke
Authors: Chang Bernard P , Cornelius Talea , Willey Joshua , Edmondson Donald , Elkind Mitchell SV , Kronish Ian M
Published: January 2020

Background

Recent evidence suggests clinical equipoise for managing transient ischaemic attack and minor stroke (TIAMS) either via discharge from the emergency department (ED) with rapid outpatient follow-up or inpatient admission. Understanding patient preferences may guide decision-making around disposition after TIAMS that can lead to higher patient satisfaction and adherence. Psychological distress, particularly a sense of vulnerability (eg, ‘threat perception’) is associated with adverse psychological outcomes following TIAMS and may influence patient disposition preference. We hypothesised patients with higher threat perceptions in the ED would prefer inpatient admission versus early discharge with rapid outpatient follow-up.

Methods

This was a planned secondary analysis of a prospective observational cohort study of ED patients with suspected TIAMS (defined as National Institutes of Health Stroke Scale (NIHSS) score of ≤5). Patients reported disposition preferences and completed a validated scale of threat perception while in the ED (score range: 1–4).

Results

147 TIAMS patients were evaluated (mean age: 59.7±15.4, 45.6% female, 39.5% Hispanic, median NIHSS=1, IQR: 0, 3). A majority of patients (98, 66.7%) preferred inpatient admission compared with discharge from the ED. Overall threat scores were median 1.0 (IQR: 0.43, 1.68). Those preferring admission had similar threat scores compared with those who preferred early disposition (median: 1.00, IQR: 0.43, 1.57) versus 1.00, (IQR: 0.49, 1.68); p=0.40). In a model adjusted for demographic characteristics, threat perceptions remained unassociated with disposition preference.

Conclusion

Overall, two-thirds of TIAMS patients preferred inpatient admission over discharge. Disposition preference was not associated with higher threat perception in the ED. Further research examining potential drivers of patient disposition preferences may inform patient discussions and optimise patient satisfaction.
Characterisation of heterozygous PMS2 variants in French patients with Lynch syndrome
Authors: Wang Qing , Leclerc Julie , Bougeard Gaëlle , Olschwang Sylviane , Vasseur Stéphanie , Cassinari Kévin , Boidin Denis , Lefol Cédrick , Naïbo Pierre , Frébourg Thierry , Buisine Marie Pierre , Baert-Desurmont Stéphanie
Published: January 2020

Background

Heterozygous germline PMS2 variants are responsible for about 5% of Lynch syndrome (LS) but their prevalence is most likely underestimated because of complicated routine screening caused by highly homologous pseudogenes. Consequently, there is limited knowledge on the implication of the PMS2 gene in LS.

Methods

We report 200 PMS2 heterozygous variants identified in 195 French patients, including 112 unique variants classified as class-3/4/5.

Results

Genomic rearrangements account for 18% of alterations. The c.137G>T variant was observed in 18% of the patients, but a founder effect could not be clearly identified by haplotype analysis. Among class-4/5 variant carriers, the median age at first tumour onset was 49 years with a predominance of colorectal (80%) and endometrial (8.1%) cancers. Seven patients developed colorectal cancers before the age of 30 with the youngest at the age of 21. Only 6.2% of class-4/5 carriers had a family history fulfilling Amsterdam I/II criteria among patients with available data. Tumours from PMS2 variant carriers exhibited microsatellite instability (96%) and loss of PMS2 expression (76%), confirming the high predictive value of somatic analysis.

Conclusion

Our results provide further insight into the role of the PMS2 gene in LS. While PMS2 variants are mostly detected in families not fulfilling Amsterdam criteria, which supports their lower penetrance, they can nevertheless cause early-onset cancers, highlighting the variability of their penetrance.
Robust measurement of clinical improvement in patients with cutaneous lupus erythematosus
Authors: Nanes Benjamin A , Zhu Jane L , Chong Benjamin F
Published: January 2020

Objective

The severity and disease course of cutaneous lupus erythematosus (CLE) are highly variable. Consequently, outcome measures for CLE clinical improvement are heterogeneous, complicating treatment decisions and therapeutic development. This study characterises CLE outcome measures and identifies the influence of clinical improvement thresholds on strengths of associations with patient demographic and clinical factors.

Methods

In this pilot cohort study, multivariable models identified factors associated with CLE activity and skin damage improvement, defined as relative decreases in Cutaneous Lupus Activity and Severity Index (CLASI) activity (CLASI-A) and damage (CLASI-D) scores, over ranges of response thresholds.

Results

66 patients with 119 visit-pairs were included in the CLASI-A analysis. 74 patients with 177 visit-pairs were included in the CLASI-D analysis. Factors associated with CLE activity and damage improvement depended on the response threshold. Some associations were stronger at more stringent thresholds, including subacute CLE predominance with increased likelihood of CLASI-A improvement (R2=0.73; 50% reduction: OR 1.724 (95% CI 0.537 to 5.536); 75%: 5.67 (95% CI 1.56 to 20.5)) and African-American race with decreased likelihood of CLASI-D improvement (R2=0.80; 20%: 0.40 (95% CI 0.17 to 0.93); 40%: 0.25 (95% CI 0.08 to 0.82)). Other associations were stable across multiple thresholds, including older age of CLE development with increased likelihood of CLASI-A improvement (R2=0.25; 50%: 1.05 (95% CI 1.01 to 1.09]; 75%: 1.05 (95% CI 1.00 to 1.10)) and higher initial disease activity with decreased likelihood of CLASI-D improvement (R2=0.55; 20%: 0.91 (95% CI 0.84 to 0.98); 40%: 0.88 (95% CI 0.79 to 0.97)).

Conclusions

Examining a range of CLASI threshold outcomes can comprehensively characterise changes in disease course in patients with CLE. Insufficiently stringent thresholds may fail to distinguish meaningful clinical change from natural fluctuation in disease activity.
Cost-effectiveness of ablation of ventricular tachycardia in ischaemic cardiomyopathy: limitations in the trial evidence base
Authors: Chen Yang , Gomes Manuel , Garcia Jason V , Hunter Ross J , Chow Anthony W , Dhinoja Mehul , Schilling Richard J , Lowe Martin , Lambiase Pier D
Published: January 2020

Objective

Catheter ablation is an important treatment for ventricular tachycardia (VT) that reduces the frequency of episodes of VT. We sought to evaluate the cost-effectiveness of catheter ablation versus antiarrhythmic drug (AAD) therapy.

Methods

A decision-analytic Markov model was used to calculate the costs and health outcomes of catheter ablation or AAD treatment of VT for a hypothetical cohort of patients with ischaemic cardiomyopathy and an implantable cardioverter-defibrillator. The health states and input parameters of the model were informed by patient-reported health-related quality of life (HRQL) data using randomised clinical trial (RCT)-level evidence wherever possible. Costs were calculated from a 2018 UK perspective.

Results

Catheter ablation versus AAD therapy had an incremental cost-effectiveness ratio (ICER) of £144 150 (€161 448) per quality-adjusted life-year gained, over a 5-year time horizon. This ICER was driven by small differences in patient-reported HRQL between AAD therapy and catheter ablation. However, only three of six RCTs had measured patient-reported HRQL, and when this was done, it was assessed infrequently. Using probabilistic sensitivity analyses, the likelihood of catheter ablation being cost-effective was only 11%, assuming a willingness-to-pay threshold of £30 000 used by the UK’s National Institute for Health and Care Excellence.

Conclusion

Catheter ablation of VT is unlikely to be cost-effective compared with AAD therapy based on the current randomised trial evidence. However, better designed studies incorporating detailed and more frequent quality of life assessments are needed to provide more robust and informed cost-effectiveness analyses.
Integrating side-scan sonar and acoustic telemetry to estimate the annual spawning run size of Atlantic sturgeon in the Hudson River
Authors: Kazyak David C. , Flowers Amy M. , Hostetter Nathan J. , Madsen John A. , Breece Matthew , Higgs Amanda , Brown Lori M. , Royle J. Andrew , Fox Dewayne A.
Published: January 2020

There is considerable interest in evaluating the status and trends of sturgeon populations, yet many traditional approaches to estimating the abundance of fishes are intractable due to their biology and rarity. Side-scan sonar has recently emerged as an effective tool for censusing sturgeon in rivers, yet challenges remain for censusing open populations that may visit specific habitats over periods of time (e.g., spawning runs). We use a hierarchical model to integrate side-scan sonar with acoustic telemetry, to estimate the proportion of a spawning run fitted with acoustic tags (12%; 95% CrI = 8%–16%) and extrapolate to the total run size in 2014. Our investigation represents a novel approach to generating run size estimates in a large river and provides the first estimate of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) spawning run size for the Hudson River ([Formula: see text] = 466; 95% CrI = 310–745) since the fishery moratorium in the 1990s. Our estimate suggests that the Hudson River holds one of the largest contemporary populations of Atlantic sturgeon, but also indicates that it remains sharply depleted relative to virgin conditions.
Plasmon mediated decomposition of brominated nucleobases on silver nanoparticles – A surface enhanced Raman scattering (SERS) study
Authors: Dutta Anushree , Schürmann Robin , Bald Ilko
Published: January 2020

The localized surface plasmon resonances (LSPRs) of silver nanoparticles (AgNPs) give rise to the generation of so called hot electrons and a high local electric field enhancement, which enable an application of AgNPs in different fields ranging from catalysis to sensing. Hot electrons generated upon the decay of LSPRs are transferred to molecules adsorbed on the surface of the NPs and trigger chemical reactions via dissociative electron attachment (DEA). Herein, we report on the hot electron induced decomposition of the brominated nucleobases – 8-bromoadenine, 8-bromoguanine, 5-bromocytosine and 5-bromouracil on laser illuminated AgNP surfaces. Surface enhanced Raman scattering (SERS) spectra of all canonical nucleobases and their brominated analogues have been recorded at different laser illumination times, and for the very first time we present SERS measurements of 8-bromoguanine and 5-bromocytosine. Reaction products have been identified by their vibrational fingerprint revealing the cleavage of the carbon bromide bond in all cases even under mild illumination conditions. These results indicate that the well-known reactions from DEA experiments in the gas phase (i) are also taking place on nanoparticle surfaces under ambient conditions, (ii) can be monitored by SERS, and (iii) are also of importance in analytical SERS applications involving electrophilic molecules, as the bands originating from reaction products need to be identified.

Graphical abstract
A high resolution multi-turn TOF mass analyzer
Authors: Shchepunov Vyacheslav , Rignall Michael , Giles Roger , Fujita Ryo , Waki Hiroaki , Nakanishi Hiroaki
Published: January 2020

An ion optical design of a high resolution multi-turn time-of-flight mass analyzer (MT-TOF MA) is presented. The analyzer has rotationally symmetric main electrodes with additional mirror symmetry about a mid-plane orthogonal to the axis of symmetry. Rotational symmetry allows a higher density of turns in the azimuthal (drift) direction compared to MT-TOF MAs that are linearly extended in the drift direction. Mirror symmetry about a mid-plane helps to achieve a high spatial isochronicity of the ions’ motion. The analyzer comprises a pair of polar-toroidal sectors S1 and S3, a pair of polar (trans-axial) lenses, and a pair of conical lenses for longitudinal and lateral focusing. A toroidal sector S2 located at the mid-plane of the analyzer has a set of embedded drift focusing segments providing focusing and spatial isochronicity in the drift direction. The ions’ drift in the azimuthal direction can be reversed by using dedicated reversing deflectors. This gives the possibility of several operational modes with different numbers of turns and passes in the drift direction. According to numerical simulations, the mass resolving power of the analyzer ranges from [Formula: see text]40 k (fwhm) at small (typically below ten) numbers of turns to [Formula: see text]450 k (fwhm) at 96 turns.
Noether identities, β-functions and symmetries in DFT
Authors: Antonio García J. , Sánchez-Isidro R. Abraham
Published: January 2020

Given the [Formula: see text] functions of the closed string sigma model up to one loop in [Formula: see text], the effective action implements the condition [Formula: see text] to preserve conformal symmetry at quantum level. One of the more powerful and striking results of string theory is that this effective action contains Einstein gravity as an emergent dynamics in space–time. We show from the [Formula: see text] functions and its relation with the equations of motion of the effective action that the differential identities are the Noether identities associated with the effective action and its gauge symmetries. From here, we reconstruct the gauge and space–time symmetries of the effective action. In turn, we can show that the differential identities are the contracted Bianchi identities of the field strength [Formula: see text] and Riemann tensor [Formula: see text]. Next, we apply the same ideas to DFT. Taking as starting point that the generalized [Formula: see text] functions in DFT are proportional to the equations of motion, we construct the generalized differential identities in DFT. Relating the Noether identities with the contracted Bianchi identities of DFT, we were able to reconstruct the generalized gauge and space–time symmetries. Finally, we recover the original [Formula: see text] functions, effective action, differential identities, and symmetries when we turn off the [Formula: see text] space–time coordinates from DFT.
DYNAMIC MEAN-VARIANCE PORTFOLIOS WITH RISK BUDGET
Authors: LUO SHENG-FENG
Published: January 2020

We study a dynamic mean-variance portfolio selection problem subject to possible limit of market risk. Three measures of market risk are considered: value-at-risk, expected shortfall, and median shortfall. They are all calculated in a dynamic consistent sense. After applying the technique of delta-normal approximation, we can explicitly solve for the optimal solution and calculate the economic loss brought by the risk budget constraint. With the analytical results obtained, influential factors of economic loss are then explored by which some guidelines on trading practice are proposed. The guidelines are independent of risk measures, and are valuable to both institutions and regulators, for they suggest that an institutional investor would spontaneously obey good investment discipline to avoid potential impact of risk constraint. This result meets the purpose of external regulation from the perspective of market discipline.
Modeling and Optimization of Rolling Process: A Multi-Objective Approach
Authors: Panda S. , Panda S. N.
Published: January 2020

In a high-speed cold strip rolling process, it is necessary to optimize the process parameters for improved quality in the product. In this study, two separate multi-objective optimization problems for a cold rolling process are formulated. The objectives in one of the cases are minimum isothermal film thickness and film temperature rise in the inlet zone and in another case it is minimum thermal film thickness and film temperature rise in the inlet zone. Particle swarm optimization algorithm has been used for solving the optimization problem. The key input parameters for the cold rolling process are identified and prioritized through the convergence study and the coefficient of variation analysis. A response analysis is performed on the critical input variables. This study assists the process engineer to understand the lubrication in cold strip rolling at high speed and select an appropriate lubricant for a given combination of strip and rolls.
Experimental Study on Investigating the Influence of Combination Combining Eccentricity with Different Orientations for Process System of Milling Center
Authors: Saeed Muhammad Junaid , Liu Can , Riaz Umair
Published: January 2020

There are several critical factors which have adverse effects on the workpiece surface finish, dimensional accuracy, tool life, etc. Eccentricity is one of them which can be manipulated when the spindle, tool holder and milling cutter revolve around the line parallel to their cutting axes and crop up due to clamping deviation and geometric imperfections. This work was driven by the observation that there should an approach through which final eccentric error can be reduced as other researchers only displayed the effects of eccentricity on cutting forces, etc. This task was carried out through performing numerous experiments on the CNC milling center and measuring geometric imperfections from the whole body of machining elements at different orientations with dial gauge to find out whether different orientations of elements have effects on the eccentricity. If they have noticeable effects then such orientations of elements exhibiting the minimum eccentricity can be selected which in turn may improve the accuracy and precision of workpieces and reduce the final cutting edge error. Our observation showed that orientations have remarkable effects on the eccentricity pretending lowest final eccentric error which is unable to be ignored.
Collapse models tested in the LNGS underground laboratories
Authors: Curceanu Catalina , Grande Raffaele Del , Laubenstein Matthias , Piscicchia Kristian
Published: January 2020

Collapse models consist in dynamical reformulations of the standard quantum mechanics aiming to solve the measurement problem. The standard Schrödinger dynamics is modified with the introduction of nonlinear and stochastic terms, which induce the wave function collapse in space. Collapse models predict slight deviations from the standard quantum mechanics predictions, in particular the emission of a “spontaneous radiation”, which we explored to set the most stringent limits on the collapse models parameters in a broad range. To this end, the X-ray emission data collected by the IGEX collaboration are analyzed and compared with the spectrum of the spontaneous photon emission process predicted by the theories. The results of the data analyses, and the ongoing experimental efforts will be presented.
Diophantine problems in solvable groups
Authors: Garreta Albert , Miasnikov Alexei , Ovchinnikov Denis
Published: January 2020

We study the Diophantine problem (decidability of finite systems of equations) in different classes of finitely generated solvable groups (nilpotent, polycyclic, metabelian, free solvable, etc.), which satisfy some natural “non-commutativity” conditions. For each group [Formula: see text] in one of these classes, we prove that there exists a ring of algebraic integers [Formula: see text] that is interpretable in [Formula: see text] by finite systems of equations ([Formula: see text]-interpretable), and hence that the Diophantine problem in [Formula: see text] is polynomial time reducible to the Diophantine problem in [Formula: see text]. One of the major open conjectures in number theory states that the Diophantine problem in any such [Formula: see text] is undecidable. If true this would imply that the Diophantine problem in any such [Formula: see text] is also undecidable. Furthermore, we show that for many particular groups [Formula: see text] as above, the ring [Formula: see text] is isomorphic to the ring of integers [Formula: see text], so the Diophantine problem in [Formula: see text] is, indeed, undecidable. This holds, in particular, for free nilpotent or free solvable non-abelian groups, as well as for non-abelian generalized Heisenberg groups and uni-triangular groups [Formula: see text]. Then, we apply these results to non-solvable groups that contain non-virtually abelian maximal finitely generated nilpotent subgroups. For instance, we show that the Diophantine problem is undecidable in the groups [Formula: see text].
Effects of W6+ substitution on the microwave dielectric properties of Ce2Zr3(MoO4)9 ceramics
Authors: Shi Liang , Liu Cheng , Zhang Huaiwu
Published: January 2020

Low temperature sintered Ce2Zr3([Formula: see text][Formula: see text][Formula: see text] (marked as CZMW) ceramics were synthesized via the conventional solid-state reaction method. X-ray diffraction results showed that the CZMW ceramics belonged to a Trigonal system with R-3C space group, and without any impure phase formation. The experimental facts revealed that the density and grain morphology greatly affected the microwave dielectric properties. The samples sintered at 825∘C exhibited good microwave dielectric properties: [Formula: see text], [Formula: see text][Formula: see text]GHz (at 11.3[Formula: see text]GHz) and a satisfactory [Formula: see text] ([Formula: see text]1.5[Formula: see text]ppm/∘C) value. It is suggested that the CZMW ceramics are suitable for low-temperature co-fired ceramic (LTCC) applications in microwave devices.
Hybrid Aeroacoustic Computations: State of Art and New Achievements
Authors: Schoder Stefan , Kaltenbacher Manfred
Published: January 2020

This paper collects the state of the art and the tremendous progress that has been made in hybrid modeling of aeroacoustic sound. Hybrid modeling is defined such that flow and acoustics are modeled separate and connected by an aeroacoustic model. The contributions will be classified with respect to the aeroacoustic models being developed, covering Lighthill’s analogy, Ffowcs Williams and Hawkings, vortex sound, linearized Euler equations (LEE), and different perturbation equations modeling flow induced sound. Within each topic, specific applications, such as jet noise, aircraft noise, ground mobility, noise, fan noise and human phonation, are covered. We focus on the accomplishments and provide the authors’ contribution to aeroacoustic research. Eventually, a concise summary of the different methods and their capabilities is included.
Lamb Waves in Functionally Graded and Laminated Composites
Authors: Ilyashenko Alla V. , Kuznetsov Sergey V.
Published: January 2020

Propagation of Lamb waves in both laminated and functionally graded (FG) composites is analyzed. Anomalous dispersion at high frequencies is observed revealing substantial discrepancy in the high frequencies asymptotes for quasi-flexural and quasi-symmetric fundamental modes. The applied methodology is based on a variant of sextic complex formalism.
Open-source tools and benchmarks for code-clone detection
Authors: Walker Andrew , Cerny Tomas , Song Eungee
Published: January 2020

A fragment of source code that is identical or similar to another is a code-clone. Code-clones make it difficult to maintain applications as they create multiple points within the code that bugs must be fixed, new rules enforced, or design decisions imposed. As applications grow larger and larger, the pervasiveness of code-clones likewise grows. To face the code-clone related issues, many tools and algorithms have been proposed to find and document code-clones within an application. In this paper, we present the historical trends in code-clone detection tools to show how we arrived at the current implementations. We then present our results from a systematic mapping study on current (2009-2019) code-clone detection tools with regards to technique, open-source nature, and language coverage. Lastly, we propose future directions for code-clone detection tools. This paper provides the essentials to understanding the code-clone detection process and the current state-of-art solutions.
Editors' introduction
Authors: Fu Hu , Weinberg S. Matthew
Published: January 2020

This issue of SIGecom Exchanges contains a letter from the SIGecom executive committee, the job market candidate profiles for 2020, a survey, three research letters, a short note, and a puzzle.
Tight revenue gaps among simple and optimal mechanisms
Authors: Jin Yaonan , Lu Pinyan , Qi Qi , Tang Zhihao Gavin , Xiao Tao
Published: January 2020

Consider a fundamental problem in microeconomics: selling a single item to a number of potential buyers, who independently draw their values from regular and publicly known distributions. There are four mechanisms widely studied in the literature and widely used in practice:
Myerson Auction (OPT), Sequential Posted Pricing (SPM), Second-Price Auction with Anonymous Reserve (AR)
, and
Anonymous Pricing (AP).

OPT
is revenue-optimal but complicated, which also experiences several practical issues such as fairness.
AP
is the simplest mechanism, but also generates the lowest revenue among these four mechanisms.
SPM
and
AR
are of intermediate complexity and revenue. A quantitative approach to comparing the relative power of these mechanisms is to study their revenue gaps, each of which is defined as the largest ratio between the revenues from a pair of mechanisms. This letter surveys some recent developments on establishing tight revenue gaps, and highlights some open questions.
Sample complexity of single-parameter revenue maximization
Authors: Guo Chenghao , Huang Zhiyi , Zhang Xinzhi
Published: January 2020

The sample complexity of learning Myerson's optimal auction from i.i.d. samples of bidders' values has received much attention since its introduction by Cole and Roughgarden (STOC 2014). This letter gives a brief introduction of a recent work that settles the sample complexity by showing matching upper and lower bounds, up to a poly-logarithmic factor, for all families of value distributions that have been considered in the literature. The upper bounds are unified under a novel framework, which builds on the strong revenue monotonicity by Devanur, Huang, and Psomas (STOC 2016), and an information theoretic argument. This is fundamentally different from the previous approaches that rely on either constructing an ∈-net of the mechanism space, either explicitly, or implicitly via statistical learning theory, or learning an approximately accurate version of the virtual values. To our knowledge, it is the first time information theoretical arguments are used to show sample complexity upper bounds, instead of lower bounds. The lower bounds are also unified under a meta construction of hard instances.
Chromatin-Modifying Enzymes in T Cell Development
Authors: Shapiro Michael J. , Shapiro Virginia Smith
Published: January 2020

T cell development involves stepwise progression through defined stages that give rise to multiple T cell subtypes, and this is accompanied by the establishment of stage-specific gene expression. Changes in chromatin accessibility and chromatin modifications accompany changes in gene expression during T cell development. Chromatin-modifying enzymes that add or reverse covalent modifications to DNA and histones have a critical role in the dynamic regulation of gene expression throughout T cell development. As each chromatin-modifying enzyme has multiple family members that are typically all coexpressed during T cell development, their function is sometimes revealed only when two related enzymes are concurrently deleted. This work has also revealed that the biological effects of these enzymes often involve regulation of a limited set of targets. The growing diversity in the types and sites of modification, as well as the potential for a single enzyme to catalyze multiple modifications, is also highlighted.
Regulatory T Cell Development
Authors: Savage Peter A. , Klawon David E.J. , Miller Christine H.
Published: January 2020

Foxp3-expressing CD4+regulatory T (Treg) cells play key roles in the prevention of autoimmunity and the maintenance of immune homeostasis and represent a major barrier to the induction of robust antitumor immune responses. Thus, a clear understanding of the mechanisms coordinating Treg cell differentiation is crucial for understanding numerous facets of health and disease and for developing approaches to modulate Treg cells for clinical benefit. Here, we discuss current knowledge of the signals that coordinate Treg cell development, the antigen-presenting cell types that direct Treg cell selection, and the nature of endogenous Treg cell ligands, focusing on evidence from studies in mice. We also highlight recent advances in this area and identify key unanswered questions.
Emergence of Turing Patterns in a Simple Cellular Automata-Like Model via Exchange of Integer Values between Adjacent Cells
Authors: Ishida Takeshi
Published: January 2020

The Turing pattern model is one of the theories used to describe organism formation patterns. Using this model, self-organized patterns emerge due to differences in the concentrations of activators and inhibitors. Here a cellular automata (CA)-like model was constructed wherein the Turing patterns emerged via the exchange of integer values between adjacent cells. In this simple hexagonal grid model, each cell state changed according to information exchanged from the six adjacent cells. The distinguishing characteristic of this model is that it presents a different pattern formation mechanism using only one kind of token, such as a chemical agent that ages via spatial diffusion. Using this CA-like model, various Turing-like patterns (spots or stripes) emerge when changing two of four parameters. This model has the ability to support Turing instability that propagates in the neighborhood space; global patterns are observed to spread from locally limited patterns. This model is not a substitute for a conventional Turing model but rather is a simplified Turing model. Using this model, it is possible to control the formation of multiple robots into such forms as circle groups or dividing a circle group into two groups, for example. In the field of information networks, the presented model could be applied to groups of Internet-of-Things devices to create macroscopic spatial structures to control data traffic.
Effect of Different Exercise Loads on Testicular Oxidative Stress and Reproductive Function in Obese Male Mice
Authors: Yi Xuejie , Tang Donghui , Cao Shicheng , Li Tao , Gao Haining , Ma Tie , Yao Tingting , Li Jing , Chang Bo
Published: January 2020

This study is aimed at investigating the effect of different exercise loads on the reproductive function of obese male mice and the underlying mechanisms. Male mice with high-fat diet-induced obesity were divided into obesity control (OC), obesity moderate-load exercise (OME), and obesity high-load exercise (OHE) groups. The OME and OHE groups were subjected to swimming exercise 5 days per week over a duration of 8 weeks, with the exercise load progressively increased to 2 h per day in the OME group and 2 h twice per day in the OHE group. In the OC group mice without exercise regimen, we observed a decrease in mRNA expression of antioxidant enzymes, increase in free radical products, upregulation of mRNA and protein expression of nuclear factor-κB and proinflammatory cytokines, inhibition of mRNA and protein expression of testosterone synthases, decrease in the serum testosterone level and sperm quality, and increase in sperm apoptosis. Although both moderate-load exercise and high-load exercise reduced body fat, only moderate-load exercise effectively alleviated obesity-induced oxidative stress, downregulated the expression of nuclear factor-κB and proinflammatory cytokines, and reversed the decrease in mRNA and protein expression of testosterone synthases, serum testosterone level, and sperm quality. These changes were not observed in the OHE group mice. Obesity-induced testicular oxidative stress and inflammatory response decreased testosterone synthesis and sperm quality. Moderate-load exercise alleviated the negative effect of obesity on male reproductive function by decreasing testicular oxidative stress and inflammatory responses. Although high-load exercise effectively reduced body fat, its effects on alleviating oxidative stress and improving male reproductive function were limited.
Subcutaneous B Cell Lymphoma in a Dog from the West Indies
Authors: Cortina Brittany , Guenthner Emily , Sypniewski Lara
Published: January 2020

A 9-year-old male castrated mixed-breed dog from the West Indies was presented for multiple, nonpainful, nodular, circumscribed, subcutaneous masses located on the dorsum, lateral thorax, head, forelimbs, and scrotum. En bloc surgical resection of a mass on the right paw, left forehead, and left medial forelimb with proportional margins was performed. Three punch biopsies were taken from the masses located along the right lateral flank. Histopathologic and immunohistochemistry (IHC) examination of the skin lesions revealed a diagnosis of subcutaneous B cell lymphoma. Thoracic radiographs and abdominal ultrasound were negative for signs of gross metastatic disease. Chemotherapeutic intervention included intravenous doxorubicin (30 mg/m2) administered at 3-week intervals for 3 treatments and oral prednisone (2 mg/kg/d) for 3 weeks. There were no complications following the chemotherapy protocol. As of 3 years, there has been no regrowth of the tumors and the patient continues to be cancer free. To date, this is the first reported case of subcutaneous B cell lymphoma diagnosed in a dog treated successfully with gross tumor resection and chemotherapy.