bluuebunny/crossref_metadata_2025 huggingface dataset:
Triggering cascades and statistical properties of aftershocks
Authors: Gu Chad , Schumann Aicko Y. , Baiesi Marco , Davidsen Jörn
Published: July 2013

Applying a simple general procedure for identifying aftershocks, we investigate their statistical properties for a high‐resolution earthquake catalog covering Southern California. We compare our results with those obtained by using other methods in order to show which features truly characterize aftershock sequences and which depend on the definition of aftershocks. Features robust across methods include thepvalue in the Omori‐Utsu law for large main shocks, Båth's law, and the productivity law with an exponent smaller than thebvalue in the Gutenberg‐Richter law. The identification of a typical aftershock distance with the rupture length is a feature we confirm as well as a power law decay in the spatial distribution of aftershocks with an exponent less than 2. Other results we obtain, but not common to all other works including Marsan and Lengliné (2008), Hainzl and Marsan (2008), and Zhuang et al. (2008), are (a)pvalues that do not increase with the main shock magnitude; (b) the duration of bare aftershock sequences that scales with the main shock magnitude; (c) an additional power law in the temporal variation, at intermediate times, in the rate of aftershocks for main shocks of small and intermediate magnitude; and (d) abvalue for the Gutenberg‐Richter law of background events that is sensibly larger than that of aftershocks. Tests on synthetic catalogs generated by the epidemic‐type aftershock sequence model corroborate the validity of our approach.
A methodology to eliminate snow‐ and ice‐contaminated solutions from GPS coordinate time series
Authors: Larson Kristine M.
Published: July 2013

Positions derived from continuously operating GPS sites are used throughout the world for geophysical research. These positions are estimated assuming that the GPS signals have not been obstructed by either snow or ice on the GPS antenna. Unfortunately, in many regions of the world, this assumption is not correct. Snow and ice attenuate and scatter the GPS signal in a way that leads to significant positioning errors. These positioning outliers are typically removed by assuming geophysical models of displacement. In this study an algorithm is developed that uses signal strength data to determine when the GPS signal has been impacted by snow or ice. This information is then used to remove outliers in GPS coordinate time series. The signal strength‐based algorithm was tested on 6 years of data from the EarthScope Plate Boundary Observatory network. The algorithm improves the precision of ~10% of these coordinate time series, with most of the improvement found for sites operating in Alaska.
Inversion of basal friction in Antarctica using exact and incomplete adjoints of a higher‐order model
Authors: Morlighem M. , Seroussi H. , Larour E. , Rignot E.
Published: July 2013

Basal friction beneath ice sheets remains poorly characterized and yet is a fundamental control on ice mechanics. Here we use a complete map of surface velocity of the Antarctic Ice Sheet to infer the basal friction over the entire continent by combining these observations with a three‐dimensional, thermomechanical, higher‐order ice sheet numerical model from the Ice Sheet System Model open source software. We demonstrate that inverse methods can be readily applied at the continental scale with appropriate selections of cost function and of scheme of regularization, at a spatial resolution as high as 3 km along the coastline. We compare the convergence of two descent algorithms with the exact and incomplete adjoints to show that the incomplete adjoint is an excellent approximation. The results reveal that the driving stress is almost entirely balanced by the basal shear stress over 80% of the ice sheet. The basal friction coefficient, which relates basal friction to basal velocity, is, however, significantly heterogeneous: it is low on fast moving ice and high near topographic divides. Areas with low values extend far out into the interior, along glacier and ice stream tributaries, almost to the flanks of topographic divides, suggesting that basal sliding is widespread beneath the Antarctic Ice Sheet.
REM sleep deprivation generates cognitive and neurochemical disruptions in the intranigral rotenone model of Parkinson's disease
Authors: Dos Santos Ana Carolina D. , Castro Marcela Alexandra V. , Jose Elis Angela K. , Delattre Ana Márcia , Dombrowski Patrícia A. , Da Cunha Claudio , Ferraz Anete C. , Lima Marcelo M.S.
Published: August 2013

The recently described intranigral rotenone model of Parkinson's disease (PD) in rodents provides an interesting model for studying mechanisms of toxin‐induced dopaminergic neuronal injury. The relevance of this model remains unexplored with regard to sleep disorders that occur in PD. On this basis, the construction of a PD model depicting several behavioral and neurochemical alterations related to sleep would be helpful in understanding the association between PD and sleep regulation. We performed bilateral intranigral injections of rotenone (12 μg) on day 0 and the open‐field test initially on day 20 after rotenone. Acquisition phase of the object‐recognition test, executed also during day 20, was followed by an exact period of 24 hr of rapid eye movement (REM) sleep deprivation (REMSD; day 21). In the subsequent day (22), the rats were re‐exposed to the open‐field test and to the object‐recognition test (choice phase). After the last session of behavioral tests, the rat brains were immediately dissected, and their striata were collected for neurochemical purposes. We observed that a brief exposure to REMSD was able to impair drastically the object‐recognition test, similarly to a nigrostriatal lesion promoted by intranigral rotenone. However, the combination of REMSD and rotenone surprisingly did not inflict memory impairment, concomitant with a moderate compensatory mechanism mediated by striatal dopamine release. In addition, we demonstrated the existence of changes in serotonin and noradrenaline neurotransmissions within the striatum mostly as a function of REMSD and REMSD plus rotenone, respectively. © 2013 Wiley Periodicals, Inc.
Community structure analysis of soil ammonia oxidizers during vegetation restoration in southwest China
Authors: Liang Yueming , He Xunyang , Liang Shichu , Zhang Wei , Chen Xiangbi , Feng Shuzheng , Su Yirong
Published: July 2013

Soil ammonia oxidizers play a critical role in nitrogen cycling and ecological restoration. The composition and structure of soil ammonia oxidizers and their impacting factors were studied in four typical ecosystem soils, tussock (T), shrub (S), secondary forest (SF), and primary forest (PF), during vegetation restoration in the Karst region of Southwest China. The composition and structure of the ammonia‐oxidizing bacteria (AOB) and ammonia‐oxidizing archaea (AOA) communities were characterized by sequencing the amoA and arch‐amoA genes, respectively. The diversity of soil ammonia oxidizers (except in S) and plant Shannon diversity index gradually increased with vegetation restoration, and the ammonia oxidizer communities differed significantly (p < 0.001). Amplicons of AOA from the Nitrososphaera cluster dominated all four ecosystem soils. AOB Nitrosospira cluster 3b only appeared in PF and SF soils, while Nitrosospira cluster 3a species were found in all soils. Changes in AOB paralleled the changes in soil ammonium content that occurred with vegetation restoration. Redundancy analysis showed that the distribution of dominant AOB species was linked to pH, soil urease activity, and soil C/N ratio, whereas the distribution of dominant AOA species was mainly influenced by litter nitrogen content and C/N ratio. These results suggested that the composition and structure of the AOB community were more sensitive to changes in vegetation and soil ammonium content, and may be an important indicator of nitrogen availability in Karst ecosystem soils.
Evaluation of various chromatographic approaches for the retention of hydrophilic compounds and MS compatibility
Authors: Periat Aurélie , Grand‐Guillaume Perrenoud Alexandre , Guillarme Davy
Published: July 2013

The goal of this study was to compare the performance of three separation techniques for the analysis of 57 hydrophilic compounds. RPLC, hydrophilic interaction liquid chromatography (HILIC) and subcritical fluid chromatography (SFC) were tested. The comparison was based on the retention, selectivity, peak shape (asymmetry and peak width) and MS sensitivity. As expected, RPLC had some obvious limitations for such classes of compounds, and on average the %ACN required to elute these hydrophilic substances was 4, 7, and 11% ACN at pH 3, 6, and 9, respectively. However, a hybrid polar‐embedded C18 phase with an appropriate mobile phase could represent a viable strategy for hydrophilic basic compounds with log D greater than –2 on average. HILIC and SFC were found to be more appropriate for analyzing a large majority of these hydrophilic analytes (∼60 and 70% of compounds eluted during the gradient in HILIC and SFC), while maintaining good MS sensitivity. Finally, this work demonstrated the complementarity of the three analytical techniques and showed that the selection of a suitable strategy should mostly be based on physicochemical properties of the analytes (pKa, log D, H‐bonding capability, etc.).
Lifetime Prevalence of Posttraumatic Stress Disorder in Two American Indian Reservation Populations
Authors: Beals Janette , Manson Spero M. , Croy Calvin , Klein Suzell A. , Whitesell Nancy Rumbaugh , Mitchell Christina M. ,   The AI‐SUPERPFP Team
Published: July 2013

Posttraumatic stress disorder (PTSD) has been found to be more common among American Indian populations than among other Americans. A complex diagnosis, the assessment methods for PTSD have varied across epidemiological studies, especially in terms of the trauma criteria. Here, we examined data from the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (AI‐SUPERPFP) to estimate the lifetime prevalence of PTSD in two culturally distinct American Indian reservation communities, using two formulas for calculating PTSD prevalence. The AI‐SUPERPFP was a cross‐sectional probability sample survey conducted between 1997 and 2000. Southwest (n = 1,446) and Northern Plains (n = 1,638) tribal members living on or near their reservations, aged 15–57 years at time of interview, were randomly sampled from tribal rolls. PTSD estimates were derived based on both the single worst and 3 worst traumas. Prevalence estimates varied by ascertainment method: single worst trauma (lifetime: 5.9% to 14.8%) versus 3 worst traumas (lifetime, 8.9% to 19.5%). Use of the 3‐worst‐event approach increased prevalence by 28.3% over the single‐event method. PTSD was prevalent in these tribal communities. These results also serve to underscore the need to better understand the implications for PTSD prevalence with the current focus on a single worst event.
Oral plus nasal corticosteroids improve smell, nasal congestion, and inflammation in sino‐nasal polyposis
Authors: Alobid Isam , Benítez Pedro , Cardelús Sara , de Borja Callejas Francisco , Lehrer‐Coriat Eduardo , Pujols Laura , Picado Cesar , Mullol Joaquim
Published: July 2013

Objectives/Hypothesis

To assess the effect of oral plus intranasal corticosteroids on subjective outcomes (smell and nasal congestion) and objective outcomes (tissue eosinophilia and nitric oxide) in severe nasal polyposis (NP).

Study Design

After a 4‐week steroid washout period (w0), severe NP were randomized into a treatment group (n = 67) that receive oral prednisone for 2 weeks (w2) plus intranasal budesonide for 12 weeks (w12), and a control group (n = 22) that received no steroid treatment.

Methods

Barcelona Smell Test 24 (BAST‐24), nasal congestion, tissue eosinophilia, and nasal nitric oxide (nNO) were assessed.

Results

Before treatment, patients showed a significant impairment of smell detection (30.7 ± 39.5%), identification (7.1 ± 16.1%), and forced choice (13.8 ± 23.3%) in BAST‐24 compared to healthy population. At w2, the treatment group showed a significant improvement in detection, identification, and forced choice. Positive effect was also seen after 12 weeks of intranasal corticosteroids. A significant reduction of nasal congestion (1.17 ± 1.0 vs. 2.73 ± 0.5) and polyp tissue eosinophilia (10.9 ± 4.2 vs. 41.2 ± 12.2) with an increase of nNO (650 ± 317 vs. 420 ± 221 ppb) were observed at w2 compared to w0 and to the control group. These effects were also seen at w12.

Conclusions

Combined oral and intranasal corticosteroids improve smell and nasal congestion and decrease nasal inflammation, as measured by reduced tissue eosinophilia and increased detection of nNO. Severity of smell loss correlates with degree of nasal congestion but not with inflammation, as measured by tissue eosinophilia or nasally exhaled nNO. Our findings suggest that improvement in smell may be related to improved conduction of odorants to the olfactory neuroepithelium.

Level of Evidence

Ib. Laryngoscope, 124:50–56, 2014
Inferior survival in liver transplant recipients with hepatocellular carcinoma receiving donation after cardiac death liver allografts
Authors: Croome Kris P. , Wall William , Chandok Natasha , Beck Gavin , Marotta Paul , Hernandez-Alejandro Roberto
Published: August 2013

The impact of ischemia/reperfusion injury in the setting of transplantation for hepatocellular carcinoma (HCC) has not been thoroughly investigated. The present study examined data from the Scientific Registry of Transplant Recipients for all recipients of deceased donor liver transplants performed between January 1, 1995 and October 31, 2011. In a multivariate Cox analysis, significant predictors of patient survival included the following: HCC diagnosis (P < 0.01), donation after cardiac death (DCD) allograft (P < 0.001), hepatitis C virus-positive status (P < 0.01), recipient age (P < 0.01), donor age (P < 0.001), Model for End-Stage Liver Disease score (P < 0.001), recipient race, and an alpha-fetoprotein level > 400 ng/mL at the time of transplantation. In order to test whether the decreased survival seen for HCC recipients of DCD grafts was more than would be expected because of the inferior nature of DCD grafts and the diagnosis of HCC, a DCD allograft/HCC diagnosis interaction term was created to look for potentiation of effect. In a multivariate analysis adjusted for all other covariates, this interaction term was statistically significant (P = 0.049) and confirmed that there was potentiation of inferior survival with the use of DCD allografts in recipients with HCC. In conclusion, patient survival and graft survival were inferior for HCC recipients of DCD allografts versus recipients of donation after brain death allografts. This potentiation of effect of inferior survival remained even after adjustments for the inherent inferiority observed in DCD allografts as well as other known risk factors. It is hypothesized that this difference could reflect an increased rate of recurrence of HCC. Liver Transpl 19:1214–1223, 2013. © 2013 AASLD.
Molecular‐Cluster‐Assembly Method for Analysis of High‐Dimensional Structures of p‐Cresol Chains in Phenolic Polymers
Authors: Ho Shirun , Aoyagi Mutsumi
Published: August 2013

A new method for analyzing oriented structures of polymers and their formation processes, called “molecular‐cluster‐assembly” (MoCA), is proposed. With this method, a polymer structure is assembled by molecular clusters at local minimum‐energy states and comprised of alternating structures along variable atomic coordinates. The reduced conformational space is searched comprehensively by using a Monte Carlo method. The total energy of the polymer structure is calculated from quantum mechanics/molecular mechanics (QM/MM) energy. It has the same accuracy as full QM energy given by the Møller–Plesset (MP2) method and the fast calculation time is the same as that of the MM method. It is shown that long p‐cresol chains form self‐organized spiral structures and composite structures with both spirals and open‐rings. As phenol groups are oriented towards the inside of the long chains, more oxygen atoms located around a hydrogen atom provide a strong negative potential. It is concluded that these two kinds of oriented structures change the dissociation energy of the hydrogen atoms in the phenol groups.
A simple and novel method for retrieval of Pasteurellaceae from swab samples collected in the field
Authors: Hansen Mie J. , Bertelsen Mads F. , Dietz Rune , Sonne Christian , Bojesen Anders M.
Published: July 2013

Traditionally it has been difficult or impossible to collect and preserve bacterial samples of especially fastidious bacteria in mixed primary cultures, unless the samples could be transported to a laboratory within approximately 24 h. Therefore, a simple novel method for preserving swab samples until bacterial isolation can be completed in the laboratory was developed and evaluated. Pasteurellaceae bacteria were used as a representative for fastidious bacteria. A 7.5% glucose serum medium was used as freeze medium. Swab samples were soaked in the medium a maximum of 2 h after collection and stored at −20°C. As a control study, 15 samples were collected from the oral cavity of a captive brown bear. One was immediately plated, while the remaining 12 swabs were stored at −20°C for 7 days and multiples of 30 days up to 330 days prior to plating. Two samples were stored without the medium for 7 and 30 days prior to plating. From a field setting in Greenland, eight polar bear samples were collected and subsequently stored for 240 to 259 days at −20°C before incubation. Pasteurellaceae bacteria were isolated and genotyped from all samples stored in the freeze medium, indicating that the medium enabled the bacteria to survive for at least 330 days at −20°C. The 100% recovery of target organisms in the polar bear samples even following lengthy storage and transport demonstrates that the method is very useful under remote field conditions.
Emerging concepts in the physiological basis of dystonia
Authors: Quartarone Angelo , Hallett Mark
Published: July 2013

Work over the past 2 decades has led to substantial changes in our understanding of dystonia pathophysiology. Three general abnormalities appear to underlie the pathophysiological substrate. The first is a loss of inhibition. This makes sense considering that it may be responsible for the excess of movement and for the overflow phenomena seen in dystonia. A second abnormality is sensory dysfunction which is related to the mild sensory complaints in patients with focal dystonias and may be responsible for some of the motor dysfunction. Third, evidence from animal models of dystonia as well as from patients with primary dystonia has revealed significant alterations of synaptic plasticity characterized by a disruption of homeostatic plasticity, with a prevailing facilitation of synaptic potentiation, together with the loss of synaptic inhibitory processes. We speculate that during motor learning this abnormal plasticity may lead to an abnormal sensorimotor integration, leading to consolidation of abnormal motor engrams. If so, then removing this abnormal plasticity might have little immediate effect on dystonic movements because bad motor memories have already been ‘‘learned'' and are difficult to erase. These considerations might explain the delayed clinical effects of deep brain stimulation (DBS) in patients with generalized dystonia. Current lines of research will be discussed from a network perspective. © 2013 Movement Disorder Society
Therapeutic strategy for lower limb lymphedema and lymphatic fistula after resection of a malignant tumor in the hip joint region: A case report
Authors: Hara H. , Mihara M. , Hayashi A. , Kanemaru M. , Todokoro T. , Yamamoto T. , Iida T. , Hino R. , Koshima I.
Published: August 2013

Lymphatic fistula complicating lymphedema is thought to occur due to communication between lymph vessels and the skin, which has yet to be shown objectively. The objective of this case report is to show the pathology and treatment using simultaneous lymphatic fistula resection and lymphatico‐venous anastomosis (LVA). A 40‐year‐old woman underwent extended resection and total hip arthroplasty for primitive neuroectodermal tumor in the right proximal femur 23 years ago. Right lower limb lymphedema developed immediately after surgery and lymphatic fistula appeared in the posterior thigh. On ICG lymphography, lymph reflux toward the distal side dispersing in a fan‐shape reticular pattern from the lymphatic fistula region was noted after intracutaneous injection of ICG into the foot. We performed simultaneous lymphatic fistula resection and of LVA. Pathological examination showed that the epidermis and stratum corneum of the healthy skin were lost in the lymphatic fistula region. Dilated lymph vessels were open in this region. The examinations provide the first objective evidence that the cause of lymphatic fistula may be lymph reflux from lymphatic stems to precollectors through lymphatic perforators. © 2013 Wiley Periodicals, Inc. Microsurgery 34:224–228, 2014.
Abdominoplasty as the patient impetus for selection of the deep inferior epigastric artery perforator free flap for knee coverage
Authors: Hallock Geoffrey G.
Published: August 2013

Extensive wounds about the knee can rarely be covered with local or even regional flaps. Free flaps often then become obligatory. Many factors will determine the surgeon's selection of the best donor site. Yet the patients' concerns with donor site morbidity cannot be overlooked. Most would agree that a large, but relatively thin flap would be optimal to preserve knee mobility. The deep inferior epigastric artery perforator (DIEAP) flap would therefore not usually be the donor site of choice from the surgeon's perspective. However, the opportunity to have a concomitant abdominoplasty that would improve body image or result in a scar readily hidden by clothing is an enticement for the patient not to be dismissed, under what normally are otherwise depressing circumstances. Over the past decade, three female patients have chosen the DIEAP free flap solely for the latter reasons, fully realizing that later flap revision would be needed to improve the function and appearance at the recipient site. © 2013 Wiley Periodicals, Inc. Microsurgery 34:102–105, 2014.
Superconvergence of fully discrete splitting positive definite mixed FEM for hyperbolic equations
Authors: Wang Fang , Chen Yanping , Tang Yuelong
Published: July 2013

In this article, we use a splitting positive definite mixed finite element procedure to solve the second‐order hyperbolic equation. We analyze the superconvergence property of the mixed element methods with discrete‐time approximation for the hyperbolic equation. Some numerical examples are presented to illustrate our theoretical results. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 175–186, 2014
Durability of LDPE nanocomposites with clay, silica, and zinc oxide II. weatherability of the nanocomposites
Authors: Redhwi Halim Hamid , Siddiqui Mohammad Nahid , Andrady Anthony L. , Syed Hussain
Published: July 2013

Three LDPE nanocomposites based on the nanoscale fillers, montmorillonite clay, silica, and zinc oxide were studied to determine if the reinforcement they imparted was accompanied by any change in the weatherability of the nanocomposite. Changes in weathering behavior were monitored in samples exposed to natural weathering outdoors over a period of 24 months of exposure. Because of superior light‐shielding afforded by the high specific surface area of nanofillers a stabilization effect might be anticipated. Alternatively chemical effects may enhance weatherability. In all three nanocomposites studied, the weatherability compared to unfilled LDPE did not significantly change due to the presence of 5 wt% of the nanofillers. The efficient reinforcement afforded by the nanofillers is not accompanied by a loss or enhancement in durability of the material. POLYM. COMPOS., 34:1878–1883, 2013. © 2013 Society of Plastics Engineers
Mechanical and electrical properties of the PA6/SWNTs nanofiber yarn by electrospinning
Authors: Li Jie , Tian Long , Pan Ning , Pan Zhi‐juan
Published: July 2013

In this article, continuous PA6/single‐wall nanotubes (SWNTs) nanofiber yarns were obtained by a special electrospinning method; the mechanical and electrical properties and the electric resistance‐tensile strain sensitivity of the as‐spun yarns were specially studied. The main parameters in the spinning process were systematically studied. Scanning electron microscope images and mechanical tests indicated that the optimum parameters for the electrospinning process were operation voltage = 20 kV, spinning flow rate = 0.09 ml/h, and winding speed = 150 rpm. Transmission electron microscopy images showed that the SWNTs have aligned along the axis of the nanofibers and thus formed a continuous conductive network which greatly improved the electrical conductivity of the PA6 nanofiber yarn and the percolation threshold was about 0.8 wt%. The electric conductivities of the yarns at different stretching ratios were also measured with a custom‐made fixture attached to the high‐resistance meter, and for a given carbon nanotube concentration, the conductivity changes almost linearly with the tensile strain applied on the yarns. POLYM. ENG. SCI., 54:1618–1624, 2014. © 2013 Society of Plastics Engineers
Influence of the bridging atom in fluorene analogue low‐bandgap polymers on photophysical and morphological properties of copper indium sulfide/polymer nanocomposite solar cells
Authors: Jäger Monika , Trattnig Roman , Postl Markus , Haas Wernfried , Kunert Birgit , Resel Roland , Hofer Ferdinand , Klug Andreas , Trimmel Gregor , List Emil J. W.
Published: August 2013

This contribution presents the correlation between structural, morphological, and fluorescence properties as well as device performance of nanocomposite solar cells comprising two low‐band gap polymers, poly[[9‐(1‐octylnonyl)−9H‐carbazole‐2,7‐diyl]‐2,5‐thiophenediyl‐2,1,3‐benzothiadiazole‐4,7‐diyl‐2,5‐thiophenediyl] (PCDTBT) and poly[2,1,3‐benzothiadiazole‐4,7‐diyl‐2,5‐thiophenediyl(9,9‐dioctyl‐9H‐9‐silafluorene‐2,7‐diyl)−2,5‐thiophenediyl] (PSiF‐DBT) and copper indium sulfide (CIS). It shows that, in analogy to organic solar cells, the device efficiency is strongly determined by different polymer structures leading to a different packing of the polymer chains and consequently to diverse morphologies. X‐ray diffraction investigation indicates increased semicrystallinity in PSiF‐DBT compared with the nitrogen analogue PCDTBT. The photoluminescence (PL) quenching of this polymer indicates that the higher photogeneration achieved in PSiF‐DBT based films can be correlated to a favorable donor‐acceptor phase separation. Transmission electron microscopy studies of PCDTBT:CIS blended films suggest the formation of polymer agglomerates in the layer resulting in a decreased PL quenching efficiency. For the considered polymer:CIS system, the combination of these effects leads to an enhanced overall device efficiency. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2013, 51, 1400–1410
Polyaniline‐tailored electromechanical responses of the silver/epoxy conductive adhesive composites
Authors: Gumfekar Sarang P. , Amoli Behnam Meschi , Chen Alex , Zhao Boxin
Published: July 2013

In this article, the electromechanical properties of silver‐in‐epoxy conductive adhesives with the polyaniline (PANI) micron particles as cofillers have been investigated. PANI is a conductive polymer and has a moderate conductivity in between those of silver and epoxy. It was found that PANI can be used to tailor both the adhesive's electrical contact resistance and its relaxation behavior; however, the effects of adding PANI were complex. The addition of small amount of PANI (2 wt %) dramatically increased the contact resistance; it might block the electrical contacts among silver flakes and was not able to form a continuous path among themselves. The addition of more PANI showed a moderate increase in contact resistance, which increased with the weight fraction of PANI from 6 to 15 wt %. Interdependent behavior of compressive strain and relaxation in electrical contact resistance is characterized to evaluate the origin of this relaxation. The addition of PANI made the relaxation in electrical contact resistance more sensitive to the compressive strain and the electromechanical coupling to deviate from the linear relationship. These research findings provide insights into the way to use PANI to tailor the electromechanical properties of the adhesive bonds or joints in the development of advanced functional devices. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013, 51, 1448–1455
Tissue dendritic cells as portals for HIV entry
Authors: Harman Andrew N. , Kim Min , Nasr Najla , Sandgren Kerrie J. , Cameron Paul U.
Published: August 2013

Dendritic cells (DCs) are found at the portals of pathogen entry such as the mucosal surfaces of the respiratory, gastrointestinal and genital tracts where they represent the first line of contact between the immune system and the foreign invaders. They are found throughout the body in multiple subsets where they express unique combinations of C‐type lectin receptors to best aid them in detection of pathogens associated with their anatomical location. DCs are important in the establishment in HIV infection for two reasons. Firstly, they are one of the first cells to encounter the virus, and the specific interaction that occurs between these cells and HIV is critical to HIV establishing a foothold infection. Secondly and most importantly, HIV is able to efficiently transfer the virus to its primary target cell, the CD4+ T lymphocyte, in which it replicates explosively. Infection of CD4+ T lymphocytes via DCs is far more efficient than direct infection. This review surveys the various DCs subsets found within the human sexual mucosa and their interactions with HIV. Mechanisms of HIV uptake are discussed as well as how the virus then traffics through the DC and is transferred to T cells. Until recently, most research has focussed on vaginal transmission despite the increased transmission rate associated with anal intercourse. Here, we also discuss recent advances in our understanding of HIV transmission in the colon. Copyright © 2013 John Wiley & Sons, Ltd.
Tectonic implications of fluvial incision and pediment deformation at the northern margin of the Central Anatolian Plateau based on multiple cosmogenic nuclides
Authors: Yildirim Cengiz , Schildgen Taylor F. , Echtler Helmut , Melnick Daniel , Bookhagen Bodo , Çiner Attila , Niedermann Samuel , Merchel Silke , Martschini Martin , Steier Peter , Strecker Manfred R.
Published: August 2013

We document Quaternary fluvial incision driven by fault‐controlled surface deformation in the inverted intermontane Gök𝚤rmak Basin in the Central Pontide mountains along the northern margin of the Central Anatolian Plateau. In‐situ‐produced 10Be, 21Ne, and 36Cl concentrations from gravel‐covered fluvial terraces and pediment surfaces along the trunk stream of the basin (the Gök𝚤rmak River) yield model exposure ages ranging from 7 ± 1 ka to 346 ± 45 ka and average fluvial incision rates over the past ~350 ka of 0.28 ± 0.01 mm a‐1. Similarities between river incision rates and coastal uplift rates at the Black Sea coast suggest that regional uplift is responsible for the river incision. Model exposure ages of deformed pediment surfaces along tributaries of the trunk stream range from 60 ± 5 ka to 110 ± 10 ka, demonstrating that the thrust faults responsible for pediment deformation were active after those times and were likely active earlier as well as explaining the topographic relief of the region. Together, our data demonstrate cumulative incision that is linked to active internal shortening and uplift of ~0.3 mm a‐1 in the Central Pontide orogenic wedge, which may ultimately contribute to the lateral growth of the northern Anatolian Plateau.
The Late Jurassic to present evolution of the Andean margin: Drivers and the geological record
Authors: Maloney Kayla T. , Clarke Geoffrey L. , Klepeis Keith A. , Quevedo Leonardo
Published: August 2013

Uncommonly long‐lived subduction and variable plate geometry along the South American Andean Plate margin resulted in diverse relationships between magmatic flux and extensional and contractional deformation, as recorded by the overriding continental plate. Convergence velocities, absolute overriding plate velocities, and subducting slab ages were resolved along the trench from 170 Ma to the present using a recently developed kinematic global plate model to identify any relationship between subduction conditions, deformation style, and magmatic features in the overriding plate. Key correlations reflect the dependence of macroscopic crustal strain style on subduction mechanism and relative plate vectors. Extensional back‐arc basins involving mafic/oceanic crust developed only when the overriding plate velocity of South America was directed away from the trench and the modeled age of the subducting slab was older than 50 Myr. The development of fold and thrust belts, and uplift of major plateaus, was accompanied by trench normal convergence velocities in excess of 4 cm/yr. Parameters investigated in this study revealed no correlation with the timing of major magmatic events, nor was any correlation observed with the structural style of fold and thrust belts.
Heterotic non-abelian orbifolds
Authors: Fischer Maximilian , Ramos-Sánchez Saúl , Vaudrevange Patrick K.S.
Published: August 2013

Abstract

We perform the first systematic analysis of particle spectra obtained from heterotic string compactifications on non-Abelian toroidal orbifolds. After developing a new technique to compute the particle spectrum in the case of standard embedding based on higher dimensional supersymmetry, we compute the Hodge numbers for all recently classified 331 non-Abelian orbifold geometries which yield
$ \mathcal{N}=1 $
supersymmetry for heterotic compactifications. Surprisingly, most Hodge numbers follow the empiric pattern h
(1,1)
− h
(2,1) = 0 mod 6, which might be related to the number of three standard model generations. Furthermore, we study the fundamental groups in order to identify the possibilities for non-local gauge symmetry breaking. Three examples are discussed in detail: the simplest non-Abelian orbifold S
3 and two more elaborate examples, T
7 and Δ(27), which have only one untwisted Kähler and no untwisted complex structure modulus. Such models might be especially interesting in the context of no-scale supergravity. Finally, we briefly discuss the case of orbifolds with vanishing Euler numbers in the context of enhanced (spontaneously broken) supersymmetry.
MicroRNA‐106b regulates the tumor suppressor RUNX3 in laryngeal carcinoma cells
Authors: Ying Xu , Kai Wang , Wei Gao , Chunming Zhang , Fuhui Huang , Shuxin Wen , Binquan Wang
Published: August 2013

Our study focuses on a set of laryngeal tumors that show reduced RUNX3 expression in the absence of transcriptional silencing of tumor suppressor gene RUNX3 by aberrant methylation of CpG islands. We report that the loss of expression of RUNX3 correlates with up‐regulation of miR‐106b in human laryngeal carcinoma tissue. The downregulation of RUNX3 is mediated by miR‐106b through binding of its 3′UTR. Moreover, miR‐106b can promote the proliferation and invasion of laryngeal carcinoma cells by directly targeting RUNX3, and RUXN3 knockdown can abolish this phenotype. These results shed a new insight into the mechanism of miRNA regulation in laryngeal carcinoma.
Direction of aminoacylated transfer RNAs into antibiotic synthesis and peptidoglycan‐mediated antibiotic resistance
Authors: Shepherd Jennifer , Ibba Michael
Published: July 2013

Prokaryotic aminoacylated‐transfer RNAs often need to be efficiently segregated between translation and other cellular biosynthetic pathways. Many clinically relevant bacteria, including Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa direct some aminoacylated‐tRNA species into peptidoglycan biosynthesis and/or membrane phospholipid modification. Subsequent indirect peptidoglycan cross‐linkage or change in membrane permeability is often a prerequisite for high‐level antibiotic resistance. In Streptomycetes, aminoacylated‐tRNA species are used for antibiotic synthesis as well as antibiotic resistance. The direction of coding aminoacylated‐tRNA molecules away from translation and into antibiotic resistance and synthesis pathways are discussed in this review.
LA GESTIÓN DEL CONOCIMIENTO EN LA INDUSTRIA UTOMOVILÍSTICA
Authors: Rivas Tovar Luis Arturo , Flores Muro Brenda
Published: August 2013

The purpose of this article is to present a brief outline of the history of knowledge management in the automobile industry on an international level. It provides a description of significant management experiences, including among others: the transformacion of implied into express knowledge (Honda), sosialization of knowledge books (Daimler Chysler)learning alliance (GM), collective learning (Irizar in Spain), and the intelligent agent’ system (Volvo). It ends with a discussion of the challeges faced by the automobile industry in Mexico with regad to nthe management of knowledge asssociated with its new free trade policy.
LA RESPONSABILIDAD SOCIAL EN EMPRESAS DEL VALLE DE TOLUCA (MÉXICO). UN ESTUDIO EXPLORATORIO
Authors: Mercado Salgado Patricia , García Hernández Patricia
Published: August 2013

In a global economy where there is still a predominant attitude of rejection towards social responsibility, the entrepreneurial sector can no longer continue to neglect the need to embrace this commitment as a means for achieving both internal and external benefits. Therefore, the purpose of this exploratory non-experimental research is to describe the social responsibility of a non-probabilistic sample of 31 companies based in the Valley of Toluca in Mexico in terms of four aspects, i.e. business ethics, environmental preservation, quality of life in the workplace, and the link between the companies and society. The results of this research reveal that these companies are now in the initial stages of developing a philanthropic orientation in which there is an external perception of the willingness on the part of upper management and shareholders as a factor that could support the embracing of social responsibility. Further similar studies should be conducted in the future using larger sample sizes and incorporating financial performance.
USO DEL INDICADOR DEL RETORNO TOTAL DEL NEGOCIO COMO ALTERNATIVA PARA OPTIMIZAR LA INVERSIÓN EN UNIDADES DE NEGOCIO EN CONDICIONES DE INCERTIDUMBRE
Authors: Herrera Echeverri Hernán
Published: August 2013

In this article we analyze the significance of the TBR (Total Business return) as a measure of corporate strategy business units rate return. We mention the weakness of the TBR and the cases when is possible accept TBR as a value creating measure. We explain the equivalence between TBR and WACC (weight average capital cost) when is calculating trough discounting forecast  cash flows and the equivalence between the CAV (additional creation value) and the subtraction between the real economic income less expected economic income. Also, we show the equality between the CAV and the variation of operations value (real operations value less expected operation value)   plus the variation of current cash flow (real current cash flow less expected current cash flow). Later, we do an application to show the use of TBR and the modern portfolio theory for return-risk relation control when the CEO must manage many strategy business units in a corporation.
¿ES EFICIENTE EL MERCADO CAMBIARIO COLOMBIANO? UNA MIRADA DESDE LAS PRUEBAS DE COINTEGRACIÓN
Authors: Alonso Julio César , Martinez Jimenez Gloria Cecilia
Published: August 2013

This paper discusses the semi-strong efficiency of the Colombian exchange market from the perspective of two different exchange regimes, i.e. the exchange rate band and the flexible exchange rate systems. This study involved the use of different co-integration tests. In addition to this, a test of restraints of the co-integration parameters developed by Ferré and Hall (2002) was used as a tool to show that the co-integration of currency exchange markets does not necessarily reflect that the markets are inefficient. The study was conducted using data about daily exchange rates. The results show that both for the exchange rate band and the flexible exchange rate systems, the Colombian exchange market is efficient.
DISEÑO DE UN SISTEMA EXPERTO DIFUSO: EVALUACIÓN DE RIESGO CREDITICIO EN FIRMAS COMISIONISTAS DE BOLSA PARA EL OTORGAMIENTO DE RECURSOS FINANCIEROS
Authors: Medina Hurtado Santiago , Manco Oscar Oswaldo
Published: August 2013

This research work reviews and describes the model of a system to allocate financial resources to stock brokerage companies and ensure that resources are invested for the benefit of the company (investor) in such a way that it not only mitigates the risk of not receiving equity payments, but also generates additional yields to the company from the equity investment. The model based on fuzzy expert systems allows sustaining these decisions of allocating financial resources. The paper initially provides a description of the necessary conceptual framework to ensure proper understanding of the system. Then it discusses a general description of the inference system, thereby taking into account the selection of entry variables and the creation of 3 integrated macro-assessments (risk analysis, fundamental analysis, and financial analysis). These assessments allow calculating the financial resources or credit limits allocated to each stock brokerage firm. The last section provides a review of 10 randomly selected firms to prove and validate the model and ensure that it yields results that are consistent with an expert assessment. The results can then be used in the everyday assessment of brokerage firms.
LA CULTURA NACIONAL Y SU IMPACTO EN LOS NEGOCIOS: EL CASO CHILENO
Authors: Hidalgo Campos Pedro , Manzur Mobarec Enrique , Olavarrieta Soto Sergio , Farías Nazel Pablo
Published: August 2013

The objective of this article is to analyze the impact of the national culture in the businesses. One of the most outstanding researchers in the analysis of the national culture is Geert Hofstede (1980). He identified four national cultural dimensions: power distance, uncertainty avoidance, individualism and masculinity. Fernandez et al. (1997) measured the Hofstede’s dimensions in Chile, characterizing to the Chileans in those four dimensions. Reviewing the Chilean empirical evidence, in this article the main effects that the Hofstede’s dimensions have in the administration, human resources and marketing are analyzed. This article has offered many examples of the way in which cultural dimensions affect the practices of organizations and is a strong argument for making cultural considerations part of strategic planning.
ESTRATEGIAS IMPLEMENTADAS EN EL SUBSISTEMA TECNICO EN EMPRESAS DE TELEFONÍA FIJA EN VENEZUELA. PERIODO 2000-2004
Authors: Artigas Wileidys , Useche María Cristina , Queipo Beatriz
Published: August 2013

The sector of telecommunications in Venezuela has been characterized for an increasing growing, changes in function of achieving a better positioning in the market are constantly carried out, in which technological aspects play an important role since it allows costs reductions and better products and services given the nature of this sector. In this sense, the main objective of this document is to describe the strategies implemented in the organization of the work for the technical subsystem of the land telephony operators companies in the state of Zulia for the period 2000-2004. The investigation has as theoretical basement, a descriptive and non experimental application of the theory of systems for administration, designed to be transeccional and to fully study the population. The data were gathered by direct observation and semistructural interviews. The conclusion is that the companies applied strategies in the technical subsystem with systemic orientation, generating a dynamic to the organization of the work in function of achieving effective interactions inside it, differentiating it of the rest of the subsystems. The technology is used as a tool applied to the products and/or services offered to the market and is also used as a solution to most of its problems; however, the systematic character of the companies is absent since it is not considered as an interaction element with other subsystems.
ENDEUDAMIENTO CONSTANTE Y COSTO DE CAPITAL CONSTANTE: CONOCIMIENTOS GENERALIZADOS PARCIALMENTE CIERTOS (Artículo publicado en inglés)
Authors: Vélez Pareja Ignacio , Ibragimov Rauf , Tham Joseph
Published: August 2013

A typical approach for valuing finite cash flows is to assume that leverage is constant (usually as target leverage) and the cost of equity, Ke and the Weighted Average Cost of Capital, WACC are also assumed to be constant. For cash flows in perpetuity, and with the cost of debt, Kd as the discount rate for the tax shield, it is indeed the case that the Ke and WACC applied to the FCF are constant if the leverage is constant. However this does not hold true for finite cash flows. In this document we show that for finite cash flows, Ke and hence WACC depend on the discount rate that is used to value the tax shield, TS and as expected, Ke and WACC are not constant with Kd as the discount rate for the tax shield, even if the leverage is constant. We illustrate this situation with a simple example. We analyze five methods: DCF using APV, FCF and traditional and general formulation for WACC, present value of CFE plus debt and Capital Cash Flow, CCF.
LA FORMA DE GOBIERNO Y SU RELACIÓN CON EL PODER Y EL CAMBIO ORGANIZACIONAL: CASO UNIVERSIDAD DEL ROSARIO
Authors: Trujillo Dávila María Andrea , Guzmán Vásquez Alexander
Published: August 2013

The purpose of this article is to analyze, according with theories about power, organizational changes, organizational capabilities, and the changes generated in the form of government of The Rosario University between 1974 and 1995. Starting of the fact that this form of government remained intact for more than three hundred years, it calls the attention how changes in the environment, characteristics of the organization and individuals that conform it, can move the organizations to begin processes that may modify their form of government, altering the distribution of the power and the roll of the actors in the scheme mentioned. These changes let The Rosario University to confront the exigencies of the environment and to conserve their capacity of governance.
COMPETENCIAS DIRECTIVAS EN ESCENARIOS GLOBALES
Authors: Puga Villarreal Julián , Martínez Cerna Luis
Published: August 2013

The environmental conditions have been changing rapidly and deeply the business. Leaders and managers of modern times need to be constantly renewing their skills to provide the intellectual tools and practices used in their daily management activities. This study aims to provide a theoretical discussion based on intensive research and field documentary on the competences that, in the logic of the present reality, leaders and top-level executives anywhere in the world need to develop, regardless of the specific environment in which they perform their duties. These skills are being increasingly demanded on the training of managers and, as seen in the literature, are linked primarily with mental capacities and/or personal – so-called soft skills – rather than mechanical skills or practices. The development of management’s competences helps improve the performance of organizations. The review of the literature shows that, in terms of identifying features that take a more comprehensive strategic vision to understand the changing environment and to improve organizational performance.