bluuebunny/crossref_metadata_2025 huggingface dataset:
The non‐linear threshold association between aspirin use and esophageal adenocarcinoma: results of a dose–response meta‐analysis
Authors: Xiaohua Ye , Zhenjiang Yao , Weidong Liu , Pengcheng Xun , Sidong Chen
Published: January 2014

Background

The role of aspirin use in chemoprevention of esophageal adenocarcinoma (EAC) is still unclear. Previous meta‐analyses have reported a beneficial effect of aspirin use, whereas it remains still under debate whether there are non‐linear frequency‐risk and duration‐risk relations, such as a “threshold” effect.

Methods

Nine observational studies reporting the association between aspirin use and EAC risk were selected through a combined search with the PUBMED and EMBASE electronic databases of articles published before June 2013. Overall odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed‐effects models, and the cubic spline regression models were performed for the study of frequency‐risk and duration‐risk relations.

Results

A monotonically decreasing relation was observed only for ≤4.5 times per week (OR = 0.75, 95%CI 0.64–0.88, for twice per week; OR = 0.59, 95%CI 0.45–0.78, for 4.5 times per week) and ≤6 years (OR = 0.82, 95%CI 0.76–0.91, for 1 year; OR = 0.53, 95%CI 0.37–0.75, for 3 years) of aspirin use using the non‐users as the reference. Once the frequency is more than 4.5 times/week or the duration is longer than 6 years, no further benefit was observed.

Conclusion

Our findings suggest that there may be non‐linear threshold relations of frequency and duration of aspirin use with the risk of EAC. Further data from randomized clinical trials are required. Copyright © 2014 John Wiley & Sons, Ltd.
Mortality, attempted suicide, re‐hospitalisation and prescription refill for clozapine and other antipsychotics in Sweden—a register‐based study
Authors: Ringbäck Weitoft Gunilla , Berglund Mats , Lindström Eva A. , Nilsson Mikael , Salmi Peter , Rosén Måns
Published: January 2014

Purpose

The aim of this study was to analyse prescription refill, re‐hospitalisation, total mortality, mortality because of suicide and attempted suicide among patients who were taking various types of antipsychotics.

Methods

A population‐based cohort study analysed all patients (n=26 046) in Sweden who had been treated for schizophrenia from 2006 to 2009 with regard to re‐hospitalisation and prescription refill for various types of antipsychotic treatment. A case‐control study nested within the cohort analysed all‐cause mortality, mortality because of suicide and attempted suicide in relation to antipsychotic use. The study adjusted for history of hospitalisation for psychiatric and medical care, attempted suicide and use of antidepressants.

Results

Aripiprazole users were the only ones who showed significantly lower all‐cause risks of death, but so few events occurred among users of this relatively new drug that the results should be interpreted with caution. Clozapine users showed lower odds of death by suicide (odds ratio [OR] = 0.45 [95%CI 0.20–0.98]) and of attempted suicide (OR = 0.44 [0.28–0.70]) than haloperidol users after adjustment for age, sex and year of discharge. Olanzapine users showed approximately the same favourable pattern. Patients who used clozapine were most likely to refill prescriptions and had lower rates of re‐hospitalisation. Only one death and 23 cases of agranulocytosis were reported compared with 223 suicides and 831 suicide attempts. An etiologic fraction calculation suggests that the use of clozapine rather than traditional drugs could have prevented 95 suicide attempts during the period.

Conclusion

Clozapine and olanzapine reduce the risk of suicide, attempted suicide and re‐hospitalisation. Copyright © 2014 John Wiley & Sons, Ltd.
Zinc oxide –From dilute magnetic doping to spin transport
Authors: Opel Matthias , Goennenwein Sebastian T. B. , Althammer Matthias , Nielsen Karl‐Wilhelm , Karrer‐Müller Eva‐Maria , Bauer Sebastian , Senn Konrad , Schwark Christoph , Weier Christian , Güntherodt Gernot , Beschoten Bernd , Gross Rudolf
Published: January 2014

During the past years, there has been renewed interest in the wide‐bandgap II–VI semiconductor ZnO, triggered by promising prospects for spintronic applications. First, ferromagnetism was predicted for dilute magnetic doping. In a comprehensive investigation of ZnO:Co thin films based on the combined measurement of macroscopic and microscopic properties, we find no evidence for carrier‐mediated itinerant ferromagnetism. Phase‐pure, crystallographically excellent ZnO:Co is uniformly paramagnetic. Superparamagnetism arises when phase separation or defect formation occurs, due to nanometer‐sized metallic precipitates. Other compounds like ZnO:(Li,Ni) and ZnO:Cu do not exhibit indication of ferromagnetism. Second, its small spin–orbit coupling and correspondingly large spin coherence length makes ZnO suitable for transporting or manipulating spins in spintronic devices. From optical pump/optical probe experiments, we find a spin dephasing time of the order of 15 ns at low temperatures, which we attribute to electrons bound to Al donors. In all‐electrical magnetotransport measurements, we successfully create and detect a spin‐polarized ensemble of electrons and transport this spin information across several nanometers. We derive a spin lifetime of 2.6 ns for these itinerant spins at low temperatures, corresponding well to results from an electrical pump/optical probe experiment.
Spin coherence of electrons and holes in ZnSe‐based quantum wells studied by pump–probe Kerr rotation
Authors: Zhukov E. A. , Yakovlev D. R. , Schwan A. , Yugov O. A. , Waag A. , Molenkamp L. W. , Bayer M.
Published: January 2014

Spin coherence of resident electrons and holes is measured in ZnSe‐based quantum wells by means of time‐resolved Kerr rotation technique. At a temperature of 1.8 K spin dephasing time for localized electrons can be as long as 33 ns, and for holes of 0.8 ns. Electron spin precession is clearly observed in a wide temperature range up to 230 K. The electron spin dephasing becomes much shorter of 0.2 ns for the quantum well with a high‐density electron gas. Using vector magnet all components of the g‐factors tensor are evaluated for the electrons and heavy‐holes, revealing strong anisotropy for the heavy‐holes.
A modified rain attenuation prediction model for tropical V‐band satellite earth link
Authors: Badron Khairayu , Ismail Ahmad Fadzil , Islam Md Rafiqul , Abdullah Khaizuran , Din Jafri , Tharek Abdul Rahman
Published: January 2014

Radio wave propagation plays a very important part in the design and eventually dictates performance of space communication systems. Over time, the requirements of satellite communication have grown extensively where higher capacity communications systems are needed. Escalating demands of microwave and millimetre wave communications are causing frequency spectrum congestion. Hence, existing and future satellite system operators are planning to employ frequency bands well above 10 GHz. The challenge in operating at such high frequencies for communication purposes is that there exists stronger electromagnetic interaction between the radio signals and atmospheric hydrometeors. Such instances will degrade the performance of such high frequency satellite communication systems. The development of a revised model for a better‐improved rain fade prediction of signal propagations in tropical region is considered very important. Researchers and engineers can employ the model to accurately plan the future high frequencies satellite services. Copyright © 2014 John Wiley & Sons, Ltd.
A game inspired defense mechanism against distributed denial of service attacks
Authors: Bedi Harkeerat , Shiva Sajjan , Roy Sankardas
Published: January 2014

Game theory offers a promising approach toward modeling cyber attacks and countermeasures as games played among attackers and system defenders. The widely accepted concept of Nash equilibrium can be used to determine the optimal strategy for all players playing the game. In this work, we demonstrate the applicability of game theory in modeling the defense against distributed denial of service attacks. In particular, we focus on attack scenarios that attempt to create congestion in bottleneck network links. We design a game model to determine the best defense strategy for the defender in such attack scenarios. In our model, the attacker uses a botnet consisting of multiple nodes to send rogue traffic in order to flood one or more links in the target network. The defender's challenge is to determine the best firewall settings to block rogue traffic while allowing legitimate traffic. We validate our game model using simulation. Furthermore, we build a comprehensive defense architecture called game inspired defense architecture and test its performance via emulation on one publicly available testbed called DeterLab. Open source software, such as Bro intrusion detection system, Dummynet network emulator, IP firewall, and Iperf network testing tool are used to build game inspired defense architecture. Our proposed defense solution exhibits promising results during both simulation and emulation. Copyright © 2014 John Wiley & Sons, Ltd.
Cloud‐based privacy‐preserving aggregation architecture in multi‐domain wireless networks
Authors: Jia Weiwei , Zhu Haojin , Du Suguo , Dong Xiaolei , Cao Zhenfu
Published: January 2014

Enabling privacy preserving outsourced data aggregation is regarded as an important issue for multi‐domain wireless networks. In this paper, we present a novel hybrid cloud‐based privacy‐preserving outsourced data aggregation framework. To achieve this, we introduce a hybrid storage cloud and aggregator cloud architecture, in which both of the storage clouds and aggregator cloud are assumed to be untrusted. On the basis of this security assumption, we firstly propose two novel basic protocols, including the proactive privacy‐preserving aggregation and reactive privacy‐preserving aggregation schemes, which are based on the idea of secret sharing. The proactive scheme allows the user to proactively split their data to multiple storage clouds to avoid data leaking while the reactive scheme allows the users to store their encrypted data in storage cloud and aggregator to finish the data aggregation based on the encrypted data. Moreover, on the basis of the proactive privacy‐preserving data aggregation and reactive privacy‐preserving data aggregation, we further propose an advanced protocol, which can resist the malicious data mining attack. The detailed performance simulations are given to demonstrate the security, effectiveness, and efficiency of the proposed scheme. Copyright © 2014 John Wiley & Sons, Ltd.
A mechanism for water splitting and hydrogen absorbing functions of metal–oxide layered hydrogen storage materials studied by means of ion beam analysis
Authors: Morita Kenji , Tsuchiya Bun
Published: January 2014

This review describes a study of catalytic functions of water splitting at the surface and hydrogen gas emitting from the bulk of metal–oxide layered materials as well as hydrogen storage materials as its application by means of the ion beam analysis techniques. First are described a microscopic model for water splitting at the oxide surface and mass balance equations for hydrogen atoms in the bulk. The latter is a mathematical expression of a one‐way diffusion model proposed for an anomalous isotope effect in D–H and H–D replacements of both deuterium (D) implanted into perovskite oxide ceramics by protium (H) in H2O vapour and the vise versa. The latter model brings about finding of catalytic functions of water splitting at the surface and hydrogen gas emitting from the bulk. Second, experimental results on the anomalous isotope effect are presented and the D–H replacement rates are described in detail. Subsequently are shown results on H2 gas emission measured with a Bach method, which give a clear evidence for the water splitting and hydrogen gas emitting catalytic functions of the oxide surface. Finally, we present experimental data on the hydrogen absorption and emission characteristics of the metal–oxide layered hydrogen storage materials as an application of the water splitting and hydrogen absorbing catalysts. Copyright © 2014 John Wiley & Sons, Ltd.
The electron spectra of beryllium and beryllium oxide: an XPS, X‐AES and AES study
Authors: Mallinson Christopher F. , Castle James E. , Watts John F.
Published: January 2014

As‐received beryllium and beryllium oxide were analysed by X‐ray photoelectron spectroscopy and Auger electron spectroscopy. Additionally, beryllium metal was scribed in vacuum and analysed by AES. Survey spectra together with high‐resolution spectra were acquired in XPS and AES mode and are presented here. The binding energies of the beryllium and the beryllium oxide Be 1s peaks were found to be 110.5 and 113.4 eV respectively, as collected by XPS, and the kinetic energies of the primary metal and oxide KLL Auger transitions were found to be 103.0 and 93.6 eV respectively, as collected by AES. Three loss peaks are also observed at 87.1, 78.0 and 67.2 eV in the AES spectrum of beryllium oxide. Copyright © 2014 John Wiley & Sons, Ltd.
Methods for comparing center‐specific survival outcomes using direct standardization
Authors: He Kevin , Schaubel Douglas E.
Published: January 2014

The evaluation of center‐specific outcomes is often through survival analysis methods. Such evaluations must account for differences in the distribution of patient characteristics across centers. In the context of censored event times, it is also important that the measure chosen to evaluate centers not be influenced by imbalances in the center‐specific censoring distributions. The practice of using center indicators in a hazard regression model is often invalid, inconvenient, or undesirable to carry out. We propose a semiparametric version of the standardized rate ratio (SRR) useful for the evaluation of centers with respect to a right‐censored event time. The SRR for centerjcan be interpreted as the ratio of the expected number of deaths in the total population (if the total population were in fact subject to the centerjmortality hazard) to the observed number of events. The proposed measure is not affected by differences in center‐specific covariate or censoring distributions. Asymptotic properties of the proposed estimators are derived, with finite‐sample properties examined through simulation studies. The proposed methods are applied to national kidney transplant data. Copyright © 2014 John Wiley & Sons, Ltd.
In Situ Quantification of Micro‐Segregation that Occurs During the Solidification of Steel
Authors: Griesser Stefan , Reid Mark , Pierer Robert , Bernhard Christian , Dippenaar Rian
Published: January 2014

We present a method for the in situ quantification of micro‐segregation during the solidification of steel by using high‐temperature laser‐scanning confocal microscopy (HTLSCM). A newly developed experimental technique that has been developed for HTLSCM has been utilized to investigate the effect of different alloying elements and cooling rates on the solidification behavior of steel. An automated quantitative measurement of the fractions of solid and liquid during solidification is used to calculate the average phase concentrations by applying a simple mass balance. The results of these analyses are in very good agreement with simulations carried out by using the commercial software package DICTRA.
Tragverhalten von Palettenregalsystemen unter Erdbebenbeanspruchung
Authors: Adamakos Kostas , Vayas Ioannis
Published: January 2014

Palettenregalsysteme weisen unterschiedliche Merkmale bezüglich der verwendeten Profile und ihrer Verbindungen auf, wodurch sie sich von üblichen Stahlbauten unterscheiden. Sie gehören nicht zu Gebäuden, so dass ihr Erdbebennachweis nicht nach den Bestimmungen für Hochbauten ausgeführt werden kann. In diesem Beitrag wird durch Anwendung nichtlinearer statischer Berechnungsverfahren das Verhalten solcher Systeme unter Erdbebenbeanspruchung untersucht. Dabei wird das nichtlineare Tragverhalten systemspezifischer Tragwerkskomponenten mit experimentellen und rechnerischen Untersuchungen bestimmt. So lassen sich Verhaltensfaktoren (q‐Faktoren) individuell für jedes Palettenregalsystem bestimmen. Ferner lässt sich ermitteln, wie ein System auf das Bemessungserdbeben reagiert bzw. inwieweit die angenommenen inelastischen Reserven ausgenutzt wurden, wie in neun Anwendungsbeispielen gezeigt wird.

Seismic performance of steel pallet racking systems. Pallet racking systems have peculiar characteristics in respect to the member’s profiles and their joints and differ from the usual steel structures. They are not buildings so that their seismic design cannot be performed according to the relevant rules for buildings. This paper presents the seismic performance of pallet racks by means of non‐linear static (pushover) analyses. The non‐linear behavior of system specific components is determined by means of experimental and numerical investigations. This allows the determination of behavior factors (q‐factors) for each individual system separately. In addition the performance of a specific system to the design earthquake may be determined as wellas how far the inelastic reserves have been exploited. The application of the method is shown by nine case studies.
Characterization of the guinea pig animal model and subsequent comparison of the behavioral effects of selective dopaminergic drugs and methamphetamine
Authors: Lee Kiera‐Nicole , Pellom Samuel T. , Oliver Ericka , Chirwa Sanika
Published: January 2014

Although not commonly used in behavior tests guinea pigs may offer subtle behavior repertoires that better mimic human activity and warrant study. To test this, 31 Hartley guinea pigs (male, 200–250 g) were evaluated in PhenoTyper cages using the video‐tracking EthoVision XT 7.0 software. Results showed that guinea pigs spent more time in the hidden zone (small box in corner of cage) than the food/water zone, or arena zone. Guinea pigs exhibited thigmotaxis (a wall following strategy) and were active throughout the light and dark phases. Eating and drinking occurred throughout the light and dark phases. An injection of 0.25 mg/kg SCH23390, the dopamine D1 receptors (D1R) antagonist, produced significant decreases in time spent in the hidden zone. There were insignificant changes in time spent in the hidden zone for guinea pigs treated with 7.5 mg SKF38393 (D1R agonist), 1.0 mg/kg sulpiride (D2R antagonist), and 1.0 or 10.0 mg/kg methamphetamine. Locomotor activity profiles were unchanged after injections of saline, SKF38393, SCH23390, and sulpiride. By contrast, a single injection or repeated administration for 7 days of low‐dose methamphetamine induced transient hyperactivity but this declined to baseline levels over the 22‐h observation period. Guinea pigs treated with high‐dose methamphetamine displayed sustained hyperactivity and travelled significantly greater distances over the circadian cycle. Subsequent 7‐day treatment with high‐dose methamphetamine induced motor sensitization and significant increases in total distances moved relative to single drug injections or saline controls. These results highlight the versatility and unique features of the guinea pig for studying brain–behavior interactions. Synapse 68:221–233, 2014. © 2014 Wiley Periodicals, Inc.
Floods and societies: the spatial distribution of water‐related disaster risk and its dynamics
Authors: Di Baldassarre Giuliano , Kemerink Jeltsje S. , Kooy Michelle , Brandimarte Luigia
Published: January 2014

This opinion article posits that the current lack of understanding of the dynamic interactions among the different components of risk (e.g., hazard, exposure, vulnerability, or resilience) is one of the main obstacles for the implementation of effective risk prevention measures. In state‐of‐the‐art methods for risk assessment, natural and social systems are typically treated separately by using different approaches. In flood risk studies, for instance, hydrological scientists typically focus on flood hazard, whereas socioeconomic scientists mainly examine the exposure, vulnerability, or resilience to flood events. However, we argue that these different components are deeply interconnected: for example, changes in flood hazard often trigger changes in vulnerability, and vice versa. These interconnections between the different components of risk remain largely unexplored and poorly understood. This lack of knowledge is of serious concern as it limits our ability to plan appropriate risk prevention measures. To design flood protection structures, for example, current methods can indeed provide quantitative assessments of the corresponding risk reduction associated to the reduced flood hazard. Nevertheless, traditional methods cannot estimate how, and to what extent, the reduced frequency or magnitude of floods might trigger increases of exposure or vulnerability to flooding (e.g., ‘levee effect’). Thus, while many progresses have been made in the static assessment of flood risk, the dynamics of risk are still poorly investigated. We think that this is a major issue in a rapidly changing world, and we therefore propose a transdisciplinary research agenda as a possible way out.

This article is categorized under:

Science of Water > Water Extremes
An open source energy system simulation model as an instrument for public participation in the development of strategies for a sustainable future
Authors: Wiese Frauke , Bökenkamp Gesine , Wingenbach Clemens , Hohmeyer Olav
Published: January 2014

The mitigation of climate change demands a decarbonisation of the energy supply of industrialized countries by 2050. This requires fundamental changes of the energy system, high efficiency improvements and a transition to 100% renewable energy supply. A successful transition will need an extremely high acceptance of the general public to be achieved in the given time frame. The necessity of new production, transmission and storage facilities can only by analyzed by highly complex analytical models, which usually are proprietary. In general it is not transparent how the results are derived. To increase the public trust in the results of the underlying modeling, the University of Flensburg is developing the open source model renpass (renewable energy pathways simulation system), for the techno‐economic simulation of the future development of the German and European electricity system. This model is supposed to be made available to the general public to scrutinize the assumptions and results of the planning process for the German ‘Energiewende,’ the transition to a 100% renewable electricity supply. The open source energy model has the goal to fulfill the requirements of full transparency and the possibility to image 100% renewable energy target systems as well as today's system and all stages of the system transition on a high regional and time resolution basis. The data input, the simulation as well as the optimization and the output are described. In the end the application possibilities especially for the ‘Energiewende’ in Germany are described and an outlook on future development is given. WIREs Energy Environ 2014, 3:490–504. doi: 10.1002/wene.109

This article is categorized under:

Energy Infrastructure > Systems and Infrastructure

Energy Policy and Planning > Systems and Infrastructure

Energy and Development > Economics and Policy

Energy and Development > Systems and Infrastructure
Synthesis and Structural Phase Transitions of Copper(II) and Iron(III) Complexes Containing [(C8H12NO)(18‐crown‐6)]+ Supramolecular Cations
Authors: Jin Yu , Yu Chun‐Hua , Wang Yu‐Feng , Li Si‐Chao , Zhang Wen
Published: January 2014

The organic‐inorganic hybrid compounds, [Cu2Cl6]2– (1), [Fe2Cl6O]2– (2), and [FeCl4]– (3), based on [(C8H12NO)(18‐crown‐6)]+ (C8H12NO = 4‐methoxybenzylammonium) supramolecular cations, were synthesized and structurally characterized. Crystal structure analyses and thermal and dielectric studies showed that compounds 1 and 2 have similar crystal packings and undergo reversible phase transitions at 230 K and 358 K, respectively. Compound 3 shows a phase transition at 361 K, though its crystal structure is remarkably different from 1 and 2. These results indicate that the phase transitions may arise from the [(C8H12NO)(18‐crown‐6)]+ supramolecular cations. The role of the chlorometalate anions is to tune the crystal packings and thus the phase transition points and types.
Flavored dark matter and R-parity violation
Authors: Batell Brian , Lin Tongyan , Wang Lian-Tao
Published: January 2014

Abstract

Minimal Flavor Violation offers an alternative symmetry rationale to R-parity conservation for the suppression of proton decay in supersymmetric extensions of the Standard Model. The naturalness of such theories is generically under less tension from LHC searches than R-parity conserving models. The flavor symmetry can also guarantee the stability of dark matter if it carries flavor quantum numbers. We outline general features of supersymmetric flavored dark matter (SFDM) models within the framework of MFV SUSY. A simple model of top flavored dark matter is presented. If the dark matter is a thermal relic, then nearly the entire parameter space of the model is testable by upcoming direct detection and LHC searches.
Strong subadditivity, null energy condition and charged black holes
Authors: Caceres Elena , Kundu Arnab , Pedraza Juan F. , Tangarife Walter
Published: January 2014

Abstract

Using the Hubeny-Rangamani-Takayanagi (HRT) conjectured formula for entanglement entropy in the context of the AdS/CFT correspondence with time-dependent backgrounds, we investigate the relation between the bulk null energy condition (NEC) of the stress-energy tensor with the strong sub-additivity (SSA) property of entanglement entropy in the boundary theory. In a background that interpolates between an AdS to an AdS-Reissner-Nordstrom-type geometry, we find that generically there always exists a critical surface beyond which the violation of NEC would naively occur. However, the extremal area surfaces that determine the entanglement entropy for the boundary theory, can penetrate into this forbidden region only for certain choices for the mass and the charge functions in the background. This penetration is then perceived as the violation of SSA in the boundary theory. We also find that this happens only when the critical surface lies above the apparent horizon, but not otherwise. We conjecture that SSA, which is thus non- trivially related to NEC, also characterizes the entire time-evolution process along which the dual field theory may thermalize.
A suspicion index for early diagnosis and treatment of cerebrotendinous xanthomatosis
Authors: Mignarri Andrea , Gallus Gian Nicola , Dotti Maria Teresa , Federico Antonio
Published: January 2014

Background

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder characterized by a heterogeneous presentation and a broad spectrum of clinical manifestations. Since early diagnosis and replacement therapy with chenodeoxycholic acid can prevent clinical deterioration, our aim was to develop a diagnostic tool to identify and treat CTX patients at an initial stage of the disease.

Methods

We devised a suspicion index, composed of weighted scores assigned to indicators such as family history characteristics and common systemic and neurological features, on the basis of a pooled analysis of selected international CTX series. The indicators were classified as very strong (score 100), strong (50) or moderate (25). The suspicion index was then applied retrospectively to our CTX population.

Results

Early systemic signs such as cataract, diarrhea and neonatal cholestatic jaundice were considered strong indicators, together with neurological features such as intellectual impairment, psychiatric disturbances, ataxia, spastic paraparesis and dentate nuclei abnormalities at MRI. Tendon xanthomas were regarded as very strong indicators, as was an affected sibling. A total score ≥ 100 warranted serum cholestanol assessment. Elevated cholestanol or a total score ≥ 200, with one very strong or four strong indicators, warranted CYP27A1 gene analysis. In our patients, age at diagnosis was 35.5 ± 11.8 years (mean ± standard deviation), whereas with the diagnostic tool it became 10.6 ± 9.8 years (p < 0.01).

Conclusions

Our suspicion index provides a simple and inexpensive diagnostic tool allowing diagnosis and treatment of CTX before neurological disability occurs.
Retorno do investimento em treinamento da pequena empresa em Cartagena
Authors: Yanez Contreras Martha , Acevedo Gonzalez Karina
Published: January 2014

O investimento em treinamento é um importante determinante da produtividade e eficiência no trabalho. O presente artigo mostra os resultados da estimação da taxa de retorno do investimento em treinamento da pequena empresa industrial em Cartagena. A metodologia proposta é a estimação de uma função de produção Cobb Douglas, uma função de salários e uma função de custos de treinamento, funções estimadas mediante modelos de efeitos fixos com variáveis instrumentais a partir do Método Generalizado dos Momentos (MGM). Os resultados mostram que um incremento num 10% nas horas de treinamento incrementa a produtividade em 4,5%, mas essas não tem impacto sobre os salários. A taxa de retorno obtida é de o 6,2% com uma taxa de depreciação de 17%.
Gerencia de las empresas familiares y no familiares: análisis comparativo
Authors: Omaña Guerrero Lenix Margarita , Briceño Barrios María Auxiliadora
Published: January 2014

En el ámbito económico existen empresas denominadas familiares cuyas características las identifican claramente. Estas organizaciones coexisten con empresas que no presentan características de familiares. Por ello el propósito del presente estudio es analizar comparativamente la gerencia en ambos tipos de empresas. La investigación se centro en un enfoque cualitativo, de tipo exploratorio y descriptivo, orientado a conocer y explicar las diferencias y semejanzas en las empresas familiares en cuanto a los siguientes aspectos: sucesión, financiamiento, órganos de gobierno, normas de funcionamiento y profesionalización, así mismo la investigación tiene un diseño documental y de campo. Los resultados arrojaron que no se encuentran evidencias significativas para afirmar que las empresas familiares y no familiares estudiadas difieren en los aspectos estudiados.
Relación entre la estrategia de innovación de la firma y su decisión de patentar: evidencia de empresas pertenecientes al sector manufacturero colombiano
Authors: Juliao Rossi Jorge Luís , Barrios Aguirre Fernando , Schmutzler Jana , Sánchez Manchola Iván Darío
Published: January 2014

El objetivo del presente artículo es determinar los efectos que ejercen la apuesta estratégica de innovación de las empresas manufactureras colombianas sobre la decisión de proteger sus innovaciones con registro de propiedad intelectual (patentes). Para lo anterior se utilizó un Zero Inflated Poisson Model (ZIP) sobre datos provenientes de la Segunda y Tercera Encuesta de Desarrollo e Innovación Tecnológica efectuada por DANE-DNP-COLCIENCIAS (EDIT-II y III). Los resultados de esta investigación evidencian una relación negativa entre la proporción de inversión en I+D y la decisión de patentar. Adicionalmente, el bajo nivel de patentes se debe en parte a la carencia de relaciones de calidad de las firmas con proveedores y competencia.
Colombia frente a la economía de conocimiento, ¿un callejón sin salida?
Authors: Pineda Leonardo
Published: January 2014

Se está ad-portas de la llamada sociedad del conocimiento donde hay una estrecha relación con el desarrollo científico-tecnológico y de innovación de los países. Este artículo trata de establecer si Colombia está preparada para ingresar a esta nueva sociedad. Tras la comparación de varias metodologías de evaluación del conocimiento y la innovación del Banco Mundial y del INSEAD, todo parece indicar que Colombia todavía está lejos de alcanzar niveles por encima de la media mundial en desarrollo científico-tecnológico y la innovación estratégica. Esta situación espera revertirse frente a las políticas y estrategias adoptadas por el Gobierno Colombiano, al incluir la ciencia, tecnología e innovación como una de las locomotoras del Plan Nacional de Desarrollo 2010-2014.
Teoría de costos de transacción, formas de gobernación y los incentivos en Colombia: un estudio de caso
Authors: Gorbaneff Yuri , Cortes Ariel , Torres Sergio , Yepes Francisco
Published: January 2014

En el presente artículo se revisa la capacidad de la teoría de costos de transacción para explicar los incentivos en la cadena de salud. Para lo anterior, se realiza a través de un estudio de caso de CPS, una aseguradora de salud en Bogotá. CPS se mueve en el ambiente de altos costos de transacción y utiliza la forma hibrida de gobernación en el nivel ambulatorio lo que está de acuerdo con la teoría. En el nivel hospitalario, a pesar de alta incertidumbre, se utiliza el mercado como forma de gobernación lo que dificulta a CPS relacionar el pago con el desempeño hospitalario. Se concluye que la teoría de costos de transacción parcialmente explica la configuración de incentivos.
La relación entre las redes externas de trabajo y el desempeño innovador de las pymes colombianas: un análisis del rol moderador del ambiente industrial
Authors: Sánchez Iván Darío , Juliao Rossi Jorge Luís , Zuluaga Jiménez Julio Cesar
Published: January 2014

Los resultados de investigaciones que analizan la relación entre redes de trabajo y desempeño innovador de las organizaciones han sido inconsistentes. Este artículo contribuye a clarificar tal situación analizando el rol moderador de la munificencia ambiental en dicha relación. En una muestra de 4.133 pymes colombianas y empleando un modelo Zero-Inflated Poisson (ZIP) se halló una relación positiva entre redes e innovación, y negativa entre munificencia e innovación. Contrario a lo esperado, se halló que a mayor munificencia ambiental la relación entre redes e innovación se hace más fuerte. Estos hallazgo destacan el valor estratégico de la redes en el contexto del proceso de innovación de las pymes y el carácter idiosincrático de dicho proceso en un país en desarrollo como Colombia.
Gestión del riesgo cambiario: aplicación a una empresa exportadora peruana
Authors: Lizarzaburu Edmundo
Published: January 2014

El presente trabajo tiene como objetivo evaluar y cuantificar el riesgo cambiario en una empresa exportadora. Se inicia explicando el riesgo cambiario, seguido de un análisis cualitativo de volatilidad cambiaria del dólar versus el nuevo sol. Este análisis resulta relevante, debido a que cada país tiene diversas características cambiarias, lo que al final impacta en el flujo de divisas, en la cotización cambiaria, entre otras. Asimismo, se explora, otros instrumentos financieros, como el factoring con recurso y el Non delivery forward (NDF) como alternativas de cobertura. Para el análisis, el rango de fechas es desde enero de 2010 a diciembre de 2012.
MicroRNA‐106a targets TIMP2 to regulate invasion and metastasis of gastric cancer
Authors: Zhu Meng , Zhang Ning , He Shuixiang , Lui Yuanyuan , Lu Guifang , Zhao Lin
Published: January 2014

Emerging evidence has shown that microRNA plays an important role in tumor development and progression. Here, we report that miR‐106a is frequently up‐regulated in gastric cancer tissues and positively correlates with metastasis. Restrained expression of miR‐106a in gastric cancer cells significantly reduces their capacity of proliferation, migration and invasion. In tissue sections, the positive signal of miR‐106a localized in metastasis‐associated regions confirmed this result. Moreover, we show that TIMP2 is a direct downstream target for miR‐106a and knockdown of TIMP2 strengthens the beneficial effects of miR‐106a. Our study adds miR‐106a to the complex mechanisms of tumor metastasis.
Proteasome involvement in a complex cascade mediating SigT degradation during differentiation of Streptomyces coelicolor
Authors: Mao Xu-Ming , Ren Ni-Ni , Sun Ning , Wang Feng , Zhou Ri-Cheng , Tang Yi , Li Yong-Quan
Published: January 2014

In Streptomyces coelicolor, the ECF sigma factor SigT negatively regulates cell differentiation, and is degraded by ClpP protease in a dual positive feedback manner. Here we further report that the proteasome is required for degradation of SigT, but not for degradation of its anti‐sigma factor RstA, and RstA can protect SigT from degradation independent of the proteasome. Meanwhile, deletion of the proteasome showed reduced production of secondary metabolites, and the fermentation medium from wild type could promote SigT degradation. Furthermore, overexpression of redD or actII‐orf4 in the proteasome‐deficiency mutant resulted in SigT degradation and over‐production of both undecylprodigiosin and actinorhodin. Therefore the proteasome is required for SigT degradation by affecting the production of secondary metabolites during cell differentiation.
Gap junction regulation by calmodulin
Authors: Zou Juan , Salarian Mani , Chen Yanyi , Veenstra Richard , Louis Charles F. , Yang Jenny J.
Published: January 2014

Intracellular Ca2+ activated calmodulin (CaM) inhibits gap junction channels in the low nanomolar to high micromolar range of [Ca2+]i. This regulation plays an essential role in numerous cellular processes that include hearing, lens transparency, and synchronized contractions of the heart. Previous studies have indicated that gap junction mediated cell‐to‐cell communication was inhibited by CaM antagonists. More recent evidence indicates a direct role of CaM in regulating several members of the connexin family. Since the intracellular loop and carboxyl termini of connexins are largely “invisible” in electron microscopy and X‐ray crystallographic structures due to disorder in these domains, peptide models encompassing the putative CaM binding sites of several intracellular domains of connexins have been used to identify the Ca2+‐dependent CaM binding sites of these proteins. This approach has been used to determine the CaM binding affinities of peptides derived from a number of different connexin‐subfamilies.
C‐reactive protein induces G2/M phase cell cycle arrest and apoptosis in monocytes through the upregulation of B‐cell translocation gene 2 expression
Authors: Kim Yuna , Ryu Jewon , Ryu Min Sook , Lim Sunny , Han Ki Ok , Lim In Kyoung , Han Ki Hoon
Published: January 2014

We hypothesized that C‐reactive protein (CRP) may affect the cell cycle and induce apoptotic changes of monocytes. CRP (∼25 μg/ml) significantly increased expressions of B‐cell translocation gene 2 (BTG2) mRNA and protein in human monocytes through pathways involving CD32/NADPH oxidase 2/p53, which eventually induced G2/M phase arrest and apoptotic cell death. Such pro‐apoptotic effect of CRP was not found in thioglycollate‐elicited intraperitoneal monocytes/macrophages harvested from BTG2‐knockout male C57BL/6 mice (n
= 5). Within atheromatous plaques obtained from CRP‐transgenic male LDLR−/− C57BL/6 mice (n
= 5) and human coronary arteries, BTG2 co‐localized with CRP, p53 and monocytes/macrophages. Therefore the pro‐apoptotic pathway of CRP‐CD32‐Nox2‐p53‐BTG2 may contribute to the retardation of the atherogenic process.
Sequential Cdk1 and Plk1 phosphorylation of caspase‐8 triggers apoptotic cell death during mitosis
Authors: Matthess Yves , Raab Monika , Knecht Rainald , Becker Sven , Strebhardt Klaus
Published: January 2014

Caspase‐8 is crucial for cell death induction, especially via the death receptor pathway. The dysregulated expression or function of caspase‐8 can promote tumor formation, progression and treatment resistance in different human cancers. Here, we show procaspase‐8 is regulated during the cell cycle through the concerted inhibitory action of Cdk1/cyclin B1 and polo‐like kinase 1 (Plk1). By phosphorylating S387 in procaspase‐8 Cdk1/cyclin B1 generates a phospho‐epitope for the binding of the PBD of Plk1. Subsequently, S305 in procaspase‐8 is phosphorylated by Plk1 during mitosis. Using an RNAi‐based strategy we could demonstrate that the extrinsic cell death is increased upon Fas‐stimulation when endogenous caspase‐8 is replaced by a mutant (S305A) mimicking the non‐phosphorylated form. Together, our data show that sequential phosphorylation by Cdk1/cyclin B1 and Plk1 decreases the sensitivity of cells toward stimuli of the extrinsic pathway during mitosis. Thus, the clinical Plk1 inhibitor BI 2536 decreases the threshold of different cancer cell types toward Fas‐induced cell death.
Transferring Inpatient Rehabilitation Facility Cancer Patients Back to Acute Care (TRIPBAC)
Authors: Asher Arash , Roberts Pamela S. , Bresee Catherine , Zabel Garret , Riggs Richard V. , Rogatko Andre
Published: January 2014

Objective

To determine predictive factors for TRansferring Inpatient rehabilitation facility (IRF) cancer Patients Back to Acute Care (TRIPBAC).

Design

A retrospective chart review of patients with cancer admitted to an IRF from 2009 to 2010 because of a functional impairment that developed as a direct consequence of their cancer or its treatment.

Setting

IRF of a community‐based, academic, tertiary care facility.

Methods

The characterization of patients with cancer in the IRF was primarily based on analysis of the IRF Patient Assessment Instrument and other internal IRF data logs.

Main Outcome Measurement

Frequency and reasons for TRIPBAC.

Results

The TRIPBAC rate in our IRF was 17.4%. The most common reasons for TRIPBAC were postneurosurgical complications (31%). Factors associated with TRIPBAC were a motor Functional Independence Measure score of 35 points or lower on admission (odds ratio 4.01, 95% confidence interval 1.79‐8.98; P = .001) and the presence of a feeding tube or a modified diet (odds ratio 3.18, 95% confidence interval 1.44‐7.04; P = .004).

Conclusions

Motor Functional Independence Measure score on admission is the best predictor for TRIPBAC in patients with cancer admitted to our IRF, followed by the presence of a feeding tube or a modified diet.
Freedom, Form, and Formlessness: Euripides’Bacchaeand Plato'sRepublic
Authors: SAXONHOUSE ARLENE W.
Published: January 2014

Liberalism begins with the free individual; the liberal state comes into being in order to preserve that freedom. Part of that freedom, to use the language of John Stuart Mill, is choosing one's own life plan, escaping the forms and lifestyles imposed on us by history or nature. Two texts from ancient Athens—Euripides’Bacchaeand Plato'sRepublic—explore the challenge posed by what I call “the escape from form.” TheBacchae, while capturing our longing for a freedom from form, portrays the devastation of a city invaded by just that freedom; theRepublic, while capturing the epistemological and political need for form, portrays a frightening vision of a city so bound by form that it becomes immobile. Socrates’ self-critique in his reconsideration of the artisan inRepublic10, however, unites the forms his Callipolis demands with the multiplicity of human identities that the god Dionysus brings to Thebes in Euripides’ tragedy.
Whole-body retention of α-linolenic acid and its apparent conversion to othern-3 PUFA in growing pigs are reduced with the duration of feeding α-linolenic acid
Authors: Martínez-Ramírez Héctor R. , Cant John P. , Shoveller Anna K. , Atkinson James L. , de Lange Cornelis F. M.
Published: January 2014

In the present study, fifteen growing pigs were used to determine the whole-body oxidation, retention efficiency (RE) and apparent conversion (AC) of α-linolenic acid (18 : 3n-3) ton-3 highly unsaturated fatty acids (HUFA), including EPA (20 : 5n-3) and DHA (22 : 6n-3). The pigs were fed a diet containing 10 % flaxseed for 30 d. Whole-body fatty acid composition was determined at initial (27·7 (se1·9) kg), intermediate (day 15; 39·2 (se1·4) kg) and final (45·7 (se2·2) kg) body weight. On day 12, four pigs were fed 10 mg/kg of uniformly labelled13C-18 : 3n-3 (single-bolus dose) to determine the oxidation of 18 : 3n-3. Expired$$CO_{2} $$samples were collected for 24 h thereafter. The whole-body content ofn-3 PUFA increased linearly (P< 0·0001) with time; however, the content of 22 : 6n-3 exhibited a quadratic response (P< 0·01) with a peak occurring at 15 h. As a proportion of intake, the RE of 18 : 3n-3 tended to reduce with time (P= 0·098). The AC of ingested 18 : 3n-3 to the sum ofn-3 HUFA was reduced with time (P< 0·05; 12·2v.7·53 % for days 0–15 and days 15–30, respectively). The AC of 18 : 3n-3 to 20 : 5n-3 or 22 : 6n-3 was lower than that to 20 : 3n-3, both for days 0–15 (P< 0·05; 1·14 or 1·07v.7·06 %) and for days 15–30 (P< 0·05; 1·51 or 0·33v.4·29 %). The direct oxidation of 18 : 3n-3 was 7·91 (se0·98) % and was similar to the calculated disappearance of 18 : 3n-3 between days 0 and 30 (8·81 (se5·24) %). The oxidation of 18 : 3n-3 was much lower than that reported in other species. The AC of 18 : 3n-3 ton-3 HUFA was reduced over time and that to 20 : 3n-3 in the present study was much higher than that reported in other species and should be explored further.
Where Have All the IPOs Gone?
Authors: Gao Xiaohui , Ritter Jay R. , Zhu Zhongyan
Published: January 2014

During 1980–2000, an average of 310 companies per year went public in the United States. Since 2000, the average has been only 99 initial public offerings (IPOs) per year, with the drop especially precipitous among small firms. Many have blamed the Sarbanes-Oxley Act of 2002 and the 2003 Global Settlement’s effects on analyst coverage for the decline in IPO activity. We find very little support for the conventional wisdom, and we offer an alternative explanation. Our economies of scope hypothesis posits that the advantages of selling out to a larger organization, which can speed a product to market and realize economies of scope, have increased relative to the benefits of operating as an independent firm.
Strandings of northern bottlenose whales,Hyperoodon ampullatus, in the north-east Atlantic: seasonality and diet
Authors: Fernández Ruth , Pierce Graham J. , MacLeod Colin D. , Brownlow Andrew , Reid Robert J. , Rogan Emer , Addink Marian , Deaville Robert , Jepson Paul D. , Santos M. Begoña
Published: January 2014

Peaks in northern bottlenose whale,Hyperoodon ampullatus, strandings are found between August and September in the UK and August and November in The Netherlands, consistent with a hypothesized southward migration. However, results on diet suggest that several whales stranded during these months were not travelling from northern latitudes prior to stranding. We analysed the stomach contents of ten whales stranded in the north-east Atlantic (Scotland, N = 6, England, N = 1, Ireland, N = 2 and The Netherlands, N = 1). All but one of the analysed whales (live-stranded in the River Thames in January 2006) stranded between August and October. Food remains consisted almost entirely of cephalopod mandibles. Twenty-one cephalopod species (16 families) were recorded, the most abundant taxa beingGonatusspp.,Teuthoweniaspp. andTaonius pavo. No fish and few crustacean remains were found. Small amounts of cephalopod flesh were found in three of the stomachs and none in the others. Given that cephalopod beaks can remain within the stomach for several days, and that there was no evidence of inshore feeding (no coastal species were present among the prey), the whales may not have fed for several days prior to stranding. Three whales had remains of warm-temperate water cephalopods (e.g.Vampyroteuthis infernalis,Heteroteuthissp.) in their stomachs, while three individuals showed a high diversity of prey in their stomachs, suggesting that several of the whales could have been either travelling north or consistently feeding in temperate latitudes prior to stranding. As previously recorded in other deep diving teuthophagous cetaceans, two animals had ingested small amounts of plastic debris.