bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of dual gate control on the alternating current performance of graphene radio frequency device
Authors: Zhu Wenjuan , Low Tony , Farmer Damon B. , Jenkins Keith , Ek Bruce , Avouris Phaedon
Published: July 2013

The excellent electrical properties of graphene, such as its high carrier mobility, gate tunability, and mechanical flexibility makes it a very promising material for radio frequency (RF) electronics. Here we study the impact of top and bottom gate control on the essential performance metrics of graphene RF transistors. We find that the maximum cut-off frequency improves as the bottom gate voltage is tuned towards the same polarity as the top gate bias voltage. These results can be explained by the bottom-gate tunable doping of the graphene underneath the metal contacts and in the under-lap region. These effects become more dramatic with device down-scaling. We also find that the minimum output conductance occurs, when the drain voltage roughly equals an effective gate voltage (Veff≈VTG+VBG⋅CBG/CTG, where VTG and VBG are top and bottom gate voltage, CTG and CBG are the respective gate capacitance). The minimum output conductance is reduced as the bottom gate bias increases, due to the stronger control of the channel from the bottom gate, lessening the influence of the drain voltage on the drain current. As a result of these two influences, when the bottom gate voltage is tuned towards the same polarity as the top gate voltage, both the maximum oscillation frequency (fmax) and the intrinsic gain significantly improve. The intrinsic gain can increase as high as 3–4 times as the gain without the bottom gate bias. Tuning the bottom gate to enhance fmax and gain will be very important elements in the effort to enable graphene RF devices for practical use.
Van der Waals interactions between graphitic nanowiggles
Authors: Phan Anh D. , Woods Lilia M. , Phan The-Long
Published: July 2013

The van der Waals interactions between two parallel graphitic nanowiggles (GNWs) are calculated using the coupled dipole method (CDM). The CDM is an efficient and accurate approach to determine such interactions explicitly by taking into account the discrete atomic structure and many-body effect. Our findings show that the van der Waals forces vary from attraction to repulsion as nanoribbons move along their lengths with respect to each other. This feature leads to a number of stable and unstable positions of the system during the movement process. These positions can be tuned by changing the length of GNW. Moreover, the influence of the thermal effect on the van der Waals interactions is also extensively investigated. This work would give good direction for both future theoretical and experimental studies.
High-peak-power surface high-harmonic generation at extreme ultra-violet wavelengths from a tape
Authors: Shaw B. H. , van Tilborg J. , Sokollik T. , Schroeder C. B. , McKinney W. R. , Artemiev N. A. , Yashchuk V. V. , Gullikson E. M. , Leemans W. P.
Published: July 2013

Solid-based surface high-harmonic generation from a tape is experimentally studied. By operating at mildly relativistic normalized laser strengths a0≲0.2, harmonics up to the 17th order are efficiently produced in the coherent wake emission (CWE) regime. CWE pulse properties, such as divergence, energy, conversion efficiency, and spectrum, are investigated for various tape materials and drive laser conditions. A clear correlation between surface roughness and harmonic beam divergence is found. At the measured pulse properties for the 15th harmonic (conversion efficiency ∼6.5×10−7, divergence ∼7−15  mrad), the 100-mJ-level drive laser produces several MWs of extreme ultra-violet pulses. The spooling tape configuration enables multi-Hz operation over thousands of shots, making this source attractive as a seed to the few-Hz laser-plasma-accelerator-driven free-electron laser (FEL). Models indicate that these CWE pulses with MW level powers are sufficient for seed-induced bunching and FEL gain.
Self-enhancement of the critical current of YBa2Cu3O7−x coated conductors caused by the axial tension
Authors: Zhang Xingyi , Yue Donghua , Zhou Jun , Zhou Youhe
Published: July 2013

We have measured the critical current of the YaBa2Cu3O7−x coated conductor under an axial tension. In the case of liquid nitrogen temperature and self-field ambient, a fascinating self-enhancement (about 25%) of the critical current of the specimens after the axial tension and a suitable waiting time were observed in the experiments. A theoretical model based on the waiting time and the tension strain is presented, which quantitatively agrees with the experimental results very well.
Mesoscopic conductance fluctuations in multi-layer graphene
Authors: Chuang Chiashain , Lin Li-Hung , Aoki Nobuyuki , Ouchi Takahiro , Mahjoub Akram M. , Woo Tak-Pong , Puddy Reuben K. , Ochiai Yuichi , Smith C. G. , Liang Chi-Te
Published: July 2013

Multi-layer graphene has many unique properties for realizing graphene-based nano-electronic device applications as well as for fundamental studies. This paper mainly focuses on the conductance fluctuations in multi-layer graphene. The low-temperature saturation of dephasing time in multi-layer graphene is one order magnitude shorter than that in single-layer graphene, and the onset temperature of the low-temperature saturation of dephasing time in multi-layer graphene was significantly lower than that in single-layer graphene, which is noteworthy in the low-temperature saturation of dephasing time. We speculate that the carrier transport is shielded by capping transport and bottom layer graphene due to the substrate impurities and air molecules scattering.
Surface enhanced Raman scattering arising from plasmonic interaction between silver nano-cubes and a silver grating
Authors: Fu Qiang , Zhang Douguo , Chen Yikai , Wang Xiangxian , Han Lu , Zhu Liangfu , Wang Pei , Ming Hai
Published: July 2013

A high effective surface enhanced Raman scattering (SERS) substrate is experimentally demonstrated, which is composed of silver nano-cubes on a silver grating. The control experiments show that the intensity of the Raman signals from this substrate is about 15.6 times as high as that from the recently proposed substrate composed of Ag nano-cubes on an Ag film. The mechanism of the better performance in SERS is discussed from the viewpoint of plasmonic interaction between the nano-cubes and the grating which can generate more hot-spots. The influence of the Ag NCs' concentration and detection ability of the substrate are also investigated.
Light trapping in thin-film solar cells via scattering by nanostructured antireflection coatings
Authors: Li X. H. , Li P. C. , Hu D. Z. , Schaadt D. M. , Yu E. T.
Published: July 2013

The use of nanostructured TiO2 layers fabricated on thin-film solar cells to provide, simultaneously, both antireflection functionality and light trapping via scattering of long-wavelength photons into guided optical modes is demonstrated and analyzed in thin-film quantum-well solar cells. Nanosphere lithography is used for fabrication of periodic arrays of subwavelength-scale TiO2 structures, and separation of active device layers from their epitaxial growth substrate and integration with the nanostructured TiO2 layer enables increased optical absorption via coupling to both Fabry-Perot resonances and guided lateral propagation modes in the semiconductor. The nanostructured TiO2 layer is shown to act as a graded-index coating at optical wavelengths and simultaneously to scatter incident light into guided optical modes within the device. The dependence of these effects on angle of incidence is also analyzed.
Thermal conductivity prediction for GaN nanowires from atomistic potential
Authors: Jung Kwangsub , Cho Maenghyo , Zhou Min
Published: July 2013

A model is developed to evaluate the thermal conductivity of semiconducting compounds as a function of their atomistic structures during phase transformations induced by mechanical loading. The approach uses atomistic configurational information and interatomic interactions as input. The harmonic and anharmonic behaviors of phonons are captured through force constants which are sensitive to structural changes. The calculations focus on changes in thermal conductivity of GaN nanowires in response to deformation and phase transformation. Results show that the model yields results consistent with data obtained using the Green-Kubo method and is 50 times more efficient than calculations based on molecular dynamics.
Antiferro quadrupolar ordering in Fe intercalated few layers graphene
Authors: Akhtar Abu Jahid , Gupta Abhisek , Chakravorty Dipankar , Saha Shyamal K.
Published: July 2013

The π electron cloud above and below the honeycomb structure of graphene causes each carbon atom to carry a permanent electric quadrupole moment which can attach any cation to impart interesting physical properties. We have synthesized Fe intercalated graphene structures to investigate tunable magnetic properties as a result of this chemical modification. An interesting antiferro quadrupolar ordering is observed which arises due to a coupling between magnetic dipole moment of Fe and electric quadrupole moment on graphene surface. In contrast to antiferromagnetic Neel temperature (TN), here the ordering temperature (TQ) increases from 35.5 K to 47.5 K as the magnetic field is raised upto 1 Tesla.
Micro-cavity 2-μm GaSb-based semiconductor disk laser using high-reflectivity SiC heatspreader
Authors: Kaspar Sebastian , Rattunde Marcel , Schilling Christian , Adler Steffen , Holl Peter , Manz Christian , Köhler Klaus , Wagner Joachim
Published: July 2013

An optically pumped GaSb-based semiconductor disk laser (SDL) emitting at 2.05 μm has been realized with a very short (380 μm long) laser cavity by high-reflectivity coating the intra-cavity SiC heatspreader, which then serves as the outcoupling mirror. Room-temperature output powers in excess of 750 mW have been demonstrated in multimode operation and still 100 mW in TEM00 emission, which is a more than 100× increase in output power compared to previous reports on GaSb-based micro-cavity (μC) SDLs. Mode-hop-free tunable single-frequency emission with linewidths <7 MHz has been achieved which makes this type of miniaturized SDLs attractive for sensing applications requiring small-size 2-μm laser sources.
Scanning tunneling microscope study of electrical transport properties of nanoscale Schottky contacts between manganese silicide nanostructures and Si(111)
Authors: Liu Xiao-Yong , Zou Zhi-Qiang , Sun Li-Min , Li Xu
Published: July 2013

The electrical transport properties of three types of manganese silicide nanocontacts, including tabular island/Si(111), nanowire/Si(111), and three-dimensional island/Si(111), are investigated by a scanning tunneling microscope with tip contacting the silicide islands. All current-voltage curves measured on the islands exhibit Schottky diode-like rectifying behaviors. Compared to the macroscopic counterparts, the nanocontacts display low Schottky barrier heights and extremely large ideality factors. The interface structure of the nanocontacts has a significant influence on the current at forward bias. This influence can be attributed to the leakage current associated with the conductive dislocations induced by the lattice mismatch between the islands and the substrate.
Coplanar electrowetting-induced stirring as a tool to manipulate biological samples in lubricated digital microfluidics. Impact of ambient phase on drop internal flow pattern
Authors: Davoust Laurent , Fouillet Yves , Malk Rachid , Theisen Johannes
Published: July 2013

Oscillating electrowetting on dielectrics (EWOD) with coplanar electrodes is investigated in this paper as a way to provide efficient stirring within a drop with biological content. A supporting model inspired from Ko et al. [Appl. Phys. Lett. 94, 194102 (2009)] is proposed allowing to interpret oscillating EWOD-induced drop internal flow as the result of a current streaming along the drop surface deformed by capillary waves. Current streaming behaves essentially as a surface flow generator and the momentum it sustains within the (viscous) drop is even more significant as the surface to volume ratio is small. With the circular electrode pair considered in this paper, oscillating EWOD sustains toroidal vortical flows when the experiments are conducted with aqueous drops in air as ambient phase. But when oil is used as ambient phase, it is demonstrated that the presence of an electrode gap is responsible for a change in drop shape: a pinch-off at the electrode gap yields a peanut-shaped drop and a symmetry break-up of the EWOD-induced flow pattern. Viscosity of oil is also responsible for promoting an efficient damping of the capillary waves which populate the surface of the actuated drop. As a result, the capillary network switches from one standing wave to two superimposed traveling waves of different mechanical energy, provided that actuation frequency is large enough, for instance, as large as the one commonly used in electrowetting applications (f ∼ 500 Hz and beyond). Special emphasis is put on stirring of biological samples. As a typical application, it is demonstrated how beads or cell clusters can be focused under flow either at mid-height of the drop or near the wetting plane, depending on how the nature of the capillary waves is (standing or traveling), and therefore, depending on the actuation frequency (150 Hz–1 KHz).
Spatial Location in Brief, Free-Viewing Face Encoding Modulates Contextual Face Recognition
Authors: Felisberti Fatima M. , McDermott Mark R.
Published: July 2013

The effect of the spatial location of faces in the visual field during brief, free-viewing encoding in subsequent face recognition is not known. This study addressed this question by tagging three groups of faces with cheating, cooperating or neutral behaviours and presenting them for encoding in two visual hemifields (upper vs. lower or left vs. right). Participants then had to indicate if a centrally presented face had been seen before or not. Head and eye movements were free in all phases. Findings showed that the overall recognition of cooperators was significantly better than cheaters, and it was better for faces encoded in the upper hemifield than in the lower hemifield, both in terms of a higher d' and faster reaction time (RT). The d' for any given behaviour in the left and right hemifields was similar. The RT in the left hemifield did not vary with tagged behaviour, whereas the RT in the right hemifield was longer for cheaters than for cooperators. The results showed that memory biases in contextual face recognition were modulated by the spatial location of briefly encoded faces and are discussed in terms of scanning reading habits, top-left bias in lighting preference and peripersonal space.
The Small Step toward Asymmetry: Aesthetic Judgment of Broken Symmetries
Authors: Gartus Andreas , Leder Helmut
Published: July 2013

Symmetry and complexity both affect the aesthetic judgment of abstract patterns. However, although beauty tends to be associated with symmetry, there are indications that small asymmetries can also be beautiful. We investigated the influence of small deviations from symmetry on people's aesthetic liking for abstract patterns. Breaking symmetry not only decreased patterns' symmetry but also increased their complexity. While an increase of complexity normally results in a higher liking, we found that even a small decrease of symmetry has a strong effect, such that patterns with slightly broken symmetries were significantly less liked than fully symmetric ones.
Germination strategies of 20 alpine species with varying seed mass and light availability
Authors: Wu Gao-Lin , Du Guo-Zhen , Shi Zhi-Hua
Published: July 2013

Seed germination is a central component of plant life history. To investigate the proposed role of seed size on germination strategy in plant communities, a semifield experiment was conducted in alpine meadow of the Qinghai–Tibetan Plateau, China. Interspecies relationships of seed mass and seed germination characteristics were studied under semifield conditions with different light availability. Light availability and seed mass had significant effects on final germination percentage and time to germination for studied species. There was a significant negative correlation between the strength of light required for germination and seed mass. Fifteen study species (e.g. Ligularia przewalskii, Artemisia sieversiana Willd, Tripolium vulgare Ness. and Saussurea morifolia Chen) exhibited a synchronous germination strategy. Seeds from large-seeded species, such as Dracocephalum ruyschiana, Laniophlomis rotate (Benth.) and Salvia przewalskii Maxim., were less likely to require light for germination than those of small-seeded species, such as A. sieversiana Willd, Senecio diversipinnus Ling and Saussurea mongolica (Franch.). We propose that germination strategies of small-seeded species are well suited to unpredictable environmental variation in this alpine grassland community.
Optimising fuel treatments over time and space
Authors: Chung Woodam , Jones Greg , Krueger Kurt , Bramel Jody , Contreras Marco
Published: July 2013

Fuel treatments have been widely used as a tool to reduce catastrophic wildland fire risks in many forests around the world. However, it is a challenging task for forest managers to prioritise where, when and how to implement fuel treatments across a large forest landscape. In this study, an optimisation model was developed for long-term fuel management decisions at a landscape scale. Using a simulated annealing algorithm, the model optimises locations and timing of fuel treatments, while considering changes in forest dynamics over time, fire behaviour and spread, values at risk, and operational feasibility. The model employs the Minimum Travel Time algorithm in FlamMap and the Fire and Fuels Extension to the Forest Vegetation Simulator to assess spatial and temporal effects with and without fuel treatments. The objective function is set to minimise total expected loss from a landscape due to wildfires throughout the planning horizon. The model was applied to a 14 000-ha study landscape located on the west side of the Bitterroot Valley in Montana. Comparisons between the optimised and random solutions show that the model was able to strategically locate and schedule fuel treatments to efficiently reduce expected loss from the landscape.
Comparison of Total Hospital-Acquired Bloodstream Infections to Central Line–Associated Bloodstream Infections and Implications for Outcome Measures in Infection Control
Authors: Leekha Surbhi , Li Shanshan , Thom Kerri A. , Preas Michael Anne , Caffo Brian S. , Morgan Daniel J. , Harris Anthony D.
Published: July 2013

The validity of the central line-associated bloodstream infection (CLABSI) measure is compromised by subjectivity. We observed significant decreases in both CLABSIs and total hospital-acquired bloodstream infections (BSIs) following a CLABSI prevention intervention in adult intensive care units. Total hospital-acquired BSIs could be explored as an adjunct, objective CLABSI measure.
Leukemia-associated RhoGEF (LARG) is a novel RhoGEF in cytokinesis and required for the proper completion of abscission
Authors: Martz Matthew K. , Grabocka Elda , Beeharry Neil , Yen Timothy J. , Wedegaertner Philip B.
Published: July 2013

Proper completion of mitosis requires the concerted effort of multiple RhoGEFs. Here we show that leukemia-associated RhoGEF (LARG), a RhoA-specific RGS-RhoGEF, is required for abscission, the final stage of cytokinesis, in which the intercellular membrane is cleaved between daughter cells. LARG colocalizes with α-tubulin at the spindle poles before localizing to the central spindle. During cytokinesis, LARG is condensed in the midbody, where it colocalizes with RhoA. HeLa cells depleted of LARG display apoptosis during cytokinesis with unresolved intercellular bridges, and rescue experiments show that expression of small interfering RNA–resistant LARG prevents this apoptosis. Moreover, live cell imaging of LARG-depleted cells reveals greatly delayed fission kinetics in abscission in which a population of cells with persistent bridges undergoes apoptosis; however, the delayed fission kinetics is rescued by Aurora-B inhibition. The formation of a Flemming body and thinning of microtubules in the intercellular bridge of cells depleted of LARG is consistent with a defect in late cytokinesis, just before the abscission event. In contrast to studies of other RhoGEFs, particularly Ect2 and GEF-H1, LARG depletion does not result in cytokinetic furrow regression nor does it affect internal mitotic timing. These results show that LARG is a novel and temporally distinct RhoGEF required for completion of abscission.
Monopolin recruits condensin to organize centromere DNA and repetitive DNA sequences
Authors: Burrack Laura S. , Applen Clancey Shelly E. , Chacón Jeremy M. , Gardner Melissa K. , Berman Judith
Published: July 2013

The establishment and maintenance of higher-order structure at centromeres is essential for accurate chromosome segregation. The monopolin complex is thought to cross-link multiple kinetochore complexes to prevent merotelic attachments that result in chromosome missegregation. This model is based on structural analysis and the requirement that monopolin execute mitotic and meiotic chromosome segregation in Schizosaccharomyces pombe, which has more than one kinetochore–microtubule attachment/centromere, and co-orient sister chromatids in meiosis I in Saccharomyces cerevisiae. Recent data from S. pombe suggest an alternative possibility: that the recruitment of condensin is the primary function of monopolin. Here we test these models using the yeast Candida albicans. C. albicans cells lacking monopolin exhibit defects in chromosome segregation, increased distance between centromeres, and decreased stability of several types of repeat DNA. Of note, changing kinetochore–microtubule copy number from one to more than one kinetochore–microtubule/centromere does not alter the requirement for monopolin. Furthermore, monopolin recruits condensin to C. albicans centromeres, and overexpression of condensin suppresses chromosome segregation defects in strains lacking monopolin. We propose that the key function of monopolin is to recruit condensin in order to promote the assembly of higher-order structure at centromere and repetitive DNA.
Fission yeast MOZART1/Mzt1 is an essential γ-tubulin complex component required for complex recruitment to the microtubule organizing center, but not its assembly
Authors: Masuda Hirohisa , Mori Risa , Yukawa Masashi , Toda Takashi
Published: July 2013

γ-Tubulin plays a universal role in microtubule nucleation from microtubule organizing centers (MTOCs) such as the animal centrosome and fungal spindle pole body (SPB). γ-Tubulin functions as a multiprotein complex called the γ-tubulin complex (γ-TuC), consisting of GCP1–6 (GCP1 is γ-tubulin). In fungi and flies, it has been shown that GCP1–3 are core components, as they are indispensable for γ-TuC complex assembly and cell division, whereas the other three GCPs are not. Recently a novel conserved component, MOZART1, was identified in humans and plants, but its precise functions remain to be determined. In this paper, we characterize the fission yeast homologue Mzt1, showing that it is essential for cell viability. Mzt1 is present in approximately equal stoichiometry with Alp4/GCP2 and localizes to all the MTOCs, including the SPB and interphase and equatorial MTOCs. Temperature-sensitive mzt1 mutants display varying degrees of compromised microtubule organization, exhibiting multiple defects during both interphase and mitosis. Mzt1 is required for γ-TuC recruitment, but not sufficient to localize to the SPB, which depends on γ-TuC integrity. Intriguingly, the core γ-TuC assembles in the absence of Mzt1. Mzt1 therefore plays a unique role within the γ-TuC components in attachment of this complex to the major MTOC site.
The Disadoption of rbST and Its Economic Impact: A Switching Regression Approach
Authors: An Henry
Published: July 2013

This paper focuses on the disadoption of rbST and addresses two key questions related to rbST use and its effects on dairy profitability. First, what are the determinants of the disadoption decision, and do they differ from those of the adoption decision? Second, do the earnings of disadopters differ from those of current adopters? Using a nationally representative dataset of U.S. dairies from 2010, a bivariate probit model with partial observability and an endogenous switching model is estimated. Consistent with other studies, the results show that rbST use does not have a statistically significant effect on dairy profitability. However, within the group of producers who have adopted rbST, I present some empirical evidence that disadopters are doing worse off than those who are still using rbST.
Hyponatraemia predicts the acute (type 1) cardio‐renal syndrome
Authors: Aronson Doron , Darawsha Wisam , Promyslovsky Marina , Kaplan Marielle , Abassi Zaid , Makhoul Badira F. , Goldberg Alexander , Azzam Zaher S.
Published: July 2013

Aims

The acute (type 1) cardio‐renal syndrome (CRS) refers to an acute worsening of heart function leading to worsening renal function (WRF), and frequently complicates acute decompensated heart failure (ADHF) and acute myocardial infarction (AMI). The aim of this study was to investigate whether hyponatraemia, a surrogate marker of congestion and haemodilution and of neurohormonal activation, could identify patients at risk for WRF.

Methods and results

We studied the association between hyponatraemia (sodium <136 mmol/L) and WRF (defined as an increase of >0.3 mg/dL in creatinine above baseline) in two separate cohorts: patients with ADHF (n = 525) and patients with AMI (n = 2576). Hyponatraemia on admission was present in 156 patients (19.7%) with ADHF and 461 patients (17.7%) with AMI. Hyponatraemia was more frequent in patients who subsequently developed WRF as compared with patients who did not, in both the ADHF (34.6% vs. 22.2%, P = 0.0003) and AMI (29.7% vs. 21.8%, P<0.01) cohorts. In a multivariable logistic regression model, the multivariable adjusted odds ratio for WRF was 1.90 [95% confidence interval (CI) 1.25–2.88; P = 0.003] and 1.56 (95% CI 1.13–2.16; P = 0.002) in the ADHF and AMI cohorts, respectively. The mortality risk associated with hyponatraemia was attenuated in the absence of WRF.

Conclusion

Hyponatraemia predicts the development of WRF in two clinical scenarios that frequently lead to the type I CRS. These data are consistent with the concept that congestion and neurohormonal activation play a pivotal role in the pathophysiology of acute cardio‐renal failure.
Identification of two novel multiple recombinant avian leukosis viruses in two different lines of layer chicken
Authors: Cai Liming , Shen Yanwei , Wang Guihua , Guo Huijun , Liu Jianzhu , Cheng Ziqiang
Published: July 2013

Avian leukosis virus (ALV) is the most common oncogenetic retrovirus that emerges spontaneously as a result of recombination between exogenous viruses, exogenous viruses and endogenous viruses, and exogenous viruses and non-homologous cellular genes. In the present study, two natural recombinant avian leukosis viruses (rALVs) (LC110515-5 and LC110803-5) carrying a subgroup C gp85 gene, a subgroup E gp37 gene, and a subgroup J 3′UTR and 3′LTR were isolated from two different lines of layer flocks, Black-bone silky fowl (BSF) and commercial layer chicken, that suffered from myeloid leukosis. Although tumours were not observed in rALV-infected individual chickens, other non-neoplastic inflammatory lesions were evident. The two rALVs were cultured on DF-1 cells and identified by PCR, immunofluorescence assay and gene sequencing. The gp85 nucleotide sequence in the two isolates displayed a high identity (>95 %) with that of the gp85 gene in ALV-C, but the identity was less than 90 % with ALV-A/B/D/E and only 51 % with ALV-J. Phylogenetic analysis of the nucleotide and amino acid sequences confirmed that the two isolates were recombinant between ALV-C, ALV-E and ALV-J. Subgroup C ALV is rarely found in field cases. This report is the first to provide evidence that ALV-C has recombined with ALV-E and ALV-J in two different chicken lines. The source and characteristics of the two rALVs and ALV-C need to be further investigated.
ROS upregulation during the early phase of retroviral infection plays an important role in viral establishment in the host cell
Authors: Kim Soo Jin , Wong Paul K. Y.
Published: July 2013

Recent studies suggest that low levels of reactive oxygen species (ROS) often modulate normal intracellular signalling pathways, determine cell fates and control cell proliferation. We found that infection of astrocytes with the neuropathogenic retrovirus ts1, a mutant of Moloney murine leukemia retrovirus, upregulated ROS at low levels during the early phase of infection. This upregulation of intracellular ROS with downregulation of NADPH levels during the early phase of ts1 infection was a separate event from the upregulation of ROS during the late phase while ts1-mediated cell death occurred. The treatment of apocynin, a potential inhibitor of NADPH oxidase (NOX), inhibited establishment of the ts1 virus in the host cell. These results suggested that ROS generated as a consequence of the activation of NOX may play an important role in the early events of the virus life cycle leading to the establishment of the virus in the host cell. The in vitro results were further supported by an in vivo experiment which showed that the treatment of apocynin decreased viral titre in the ts1-infected mouse brain and increased the lifespan of infected mice. This study provides the first in vitro and in vivo evidence on a mechanism for how ROS are involved in ts1 retrovirus infection and ts1-mediated neurodegenerative disease. Our findings focusing on the early phase of the ts1 retrovirus life cycle could provide a better understanding of retroviral life cycle, which may offer specific therapeutic targets for suppressing viral replication and alleviating neurodegenerative symptoms in a mouse model.
Derivatives as risk management and performance of agricultural banks
Authors: Shen Xuan , Hartarska Valentina
Published: July 2013

Purpose

The purpose of this paper is to estimate the impact of financial derivatives on profitability in agricultural banks. Agricultural banks are new to the derivatives market and are unlikely to use financial derivatives for risk speculation. Thus, the paper also provides evidence on the effectiveness of financial derivatives as a risk management tool in small commercial banks.

Design/methodology/approach

The authors use call report data from Federal Reserve Bank of Chicago for 2006, 2008 and 2010 to estimate an endogenous switching model to evaluate how profitability of derivatives user and non‐user agricultural banks is affected by different risk factors. This approach allows banks' endogenous choices to use financial derivatives to be accounted for, and to build a counterfactual analysis – what user banks' profitability would have been if they did not participate in the derivatives activities.

Findings

Results indicate that risk management through financial derivatives in agricultural banks is effective and profitability of derivatives user agricultural banks is less affected by credit risk and interest risk in the sample period. Derivatives' activities have improved agricultural banks' profitability and these impacts were increasing over years. In particular, in 2010 without use of derivatives, user banks would have had one‐third lower profitability.

Originality/value

This research is the first to study the role of derivatives in agricultural banks and also provides empirical evidence on the effectiveness of risk management through financial derivatives in agricultural banks.
Gender differences in self‐reported symptoms of depression and anxiety in adults with intellectual disabilities
Authors: Chester Rebecca , Chaplin Eddie , Tsakanikos Elias , McCarthy Jane , Bouras Nick , Craig Tom
Published: July 2013

Purpose

This study aimed to examine for differences on how symptoms relating to depression and anxiety were reported by males and females with intellectual disability as part of the development of the Self‐Assessment Intervention Package (SAINT), a guided self‐help tool.

Design/methodology/approach

Three self‐report questionnaires were administered (The Glasgow Depression Scale – Learning Disabilities (GDS‐LD)), Glasgow Anxiety Scale – Intellectual Disabilities (GAS‐ID) and Self‐Assessment Intervention Package (SAINT) to a group of people with mild intellectual disabilities (n=36), to allow comparison of symptom reporting between genders, in particular examining the SAINT across the two groups.

Findings

Statistically significant differences in self‐reported symptoms as assessed with SAINT were found between males and females. The symptoms where related mainly to mood and self‐esteem. Overall, endorsement of self‐reported depressive symptoms was between 2.7‐3.2 times higher in female than male patients.

Originality/value

There was evidence to suggest differences in self‐report and symptom profiles of depression and anxiety of males and females with mild intellectual disabilities with females reporting higher in terms of symptoms using the SAINT. The SAINT is a valid tool for screening and self‐reporting symptoms of anxiety and depression in people with intellectual disabilities.
Dark tourism revisited: a supply/demand conceptualisation
Authors: Farmaki Anna
Published: July 2013

Purpose

The purpose of this paper is to advance the conceptualisation of dark tourism by evaluating both the supply‐side drivers for dark tourism development and the demand‐side motivations for visiting two dark heritage sites in Cyprus.

Design/methodology/approach

An exploratory research approach was adopted whereby 12 semi‐structured interviews were conducted with supply‐side stakeholders and two focus groups were conducted with local and foreign visitors.

Findings

Production and consumption of dark tourism is continuous and interrelated as demand appears to be supply‐driven and attraction‐based. Tourist interpretations of dark tourism are influenced by tourists' personal factors, the passage of “time” and the way the dark site is projected by the supply‐side. A refined marketing segmentation strategy is proposed taking into consideration the purpose of visit, the relevance of the dark heritage site to the tourist and the depth of the dark element.

Originality/value

The study's focus is narrow but the findings provide theoretical and practical insights into the conceptualisation dark tourism by considering supply and demand aspects and the related influencing factors. In doing so understanding of the phenomenon is enhanced.
When death is the destination: the business of death tourism – despite legal and social implications
Authors: Shondell Miller DeMond , Gonzalez Christopher
Published: July 2013

Purpose

This paper views the growing popularity of death tourism which directs the confrontation with grief and mortality with the expressed purpose of orchestrating travel that culminates in assistance to end one's life. The specific aims of this paper are to describe the emerging phenomenon of death tourism and situate it as a form of dark tourism, to present briefly the social and legal aspects of assisted suicide in conjunction within the tourism industry, and to conclude with how the trend of death tourism is potentially spreading to other countries beyond Europe.

Design/methodology/approach

By employing a variety of primary and secondary resources, from death tourism industry documents, legal statutes, and news reports, this study explores the propositions of this article.

Findings

Whereas much of the contemporary research in dark tourism focuses on sights, experiences, and actual memorialization, death tourism tends to comprise a holistic view of the emerging phenomenon by viewing supply and demand management (and promotion), political interpretation and control. The final component of the paper views societal interpretations of death tourism and its potential for market expansion.

Research limitations/implications

There have been several social movements and legislative attempts to curtail the spread of assisted suicide and death tourism; however, the demand for the services has grown to the point where jurisdictions are considering measures to allow this practice. Such an expansion of legalized assisted suicide will allow those seeking the right to die more options for a death within a diversified tourism industry.

Originality/value

Death tourism, within dark tourism, represents an emerging field with few academic resources. This paper works to conceptualize and clarify the unique place death tourism holds within tourism and dark tourism specifically.
Dark tourism and voyeurism: tourist arrested for “spying” in Iran
Authors: Buda Dorina Maria , McIntosh Alison Jane
Published: July 2013

Purpose

The purpose of this paper is to propose voyeurism as one possible lens to analyse the experiential nature of dark tourism in places of socio‐political danger, thus expanding psychoanalytic understandings of those who travel to a “dark” place.

Design/methodology/approach

Freud's and Lacan's theories on voyeurism are used to examine the desire to travel to and gaze upon something that is (socially constructed as) forbidden, such as a place that is portrayed as being hostile to international tourists. A qualitative and critical analysis approach is employed to examine one tourist's experience of travelling to Iran and being imprisoned as a result of taking a photograph of what he thought was a sunrise but also pictured pylons near an electrical plant.

Findings

The authors' analysis of the experiences of this tourist in Iran reveals that tourism, in its widest sense, can be experienced as “dark” through the consumption and performance of danger. This finding moves beyond the examination of dark tourism merely as “tourist products”, or that frame a particular moment in time, or are merely founded on one's connection to or perception of the site.

Research limitations/implications

Whilst the authors recognise the limitations of the case study approach taken here, and as such, generalisations cannot be inferred from the findings, it is argued that there is merit in exploring critically the motivational and experiential nature of travel to places that may be considered forbidden, dangerous or hostile in an attempt to further understand the concept of dark tourism from a tourist's lived perspective.

Originality/value

As the authors bring voyeurism into the debate on dark tourism, the study analyses the voyeuristic experiences of a dark tourist. In short, the authors argue that the lived and “deviant” experiential nature of tourism itself can be included in the discussion of “dark tourism”.
New graduate occupational therapists' perceptions of near‐misses and mistakes in the workplace
Authors: Clark Michele , Gray Marion , Mooney Jane
Published: July 2013

Purpose

The purpose of this paper is to explore the perceptions of near‐misses and mistakes among new graduate occupational therapists from Australia and Aotearoa/New Zealand (NZ), and their knowledge of current incident reporting systems.

Design/methodology/approach

New graduate occupational therapists in Australia and Aotearoa/NZ in their first year of practice (n=228) participated in an online electronic survey that examined five areas of work preparedness. Near‐misses and mistakes was one focus area.

Findings

The occurrence and disclosure of practice errors among new graduate occupational therapists are similar between Australian and Aotearoa/NZ participants. Rural location, structured supervision and registration status significantly influenced the perceptions and reporting of practice errors. Structured supervision significantly impacted on reporting procedure knowledge. Current registration status was strongly correlated with perceptions that the workplace encouraged event reporting.

Research limitations/ implications

Areas for further investigation include investigating the perceptions and knowledge of practice errors within a broader profession and the need to explore definitional aspects and contextual factors of adverse events that occur in allied health settings. Selection bias may be a factor in this study.

Practical implications

Findings have implications for university and workplace structures, such as clinical management, supervision, training about practice errors and reporting mechanisms in allied health.

Originality/value

Findings may enable the development of better strategies for detecting, managing and preventing practice errors in the allied health professions.
Fingerprinting Tor
Authors: Carballude González Pablo
Published: July 2013

Purpose

It is increasingly difficult to ignore the importance of anonymity on the internet. Tor has been proposed as a reliable way to keep our identity secret from governments and organizations. This research evaluates its ability to protect our activity on the Web.

Design/methodology/approach

Using traffic analysis over ACK packets among others, fingerprints of websites can be created and later on used to recognise Tor traffic.

Findings

Tor does not add enough entropy to HTTP traffic, which allows us to recognise the access to static websites without breaking Tor's cryptography.

Research limitations/implications

This work shows that the method presented behaves well with a limited set of fingerprints. Further research should be performed on its reliability with larger sets.

Social implications

Tor has been used by political dissidents and citizens in countries without freedom of speech to access banned websites such as Twitter or Facebook. This paper shows that it might be possible for their countries to know what they have done.

Originality/value

This paper shows that while Tor does a good work keeping the content of our communication, it is weak protecting the identity of the website being accessed.
Revisiting the myth of Cisco IOS diversity: recent advances in reliable shellcode design
Authors: Cui Ang , Kataria Jatin , Stolfo Salvatore J.
Published: July 2013

Purpose

IOS firmware diversity, the unintended consequence of a complex firmware compilation process, has historically made reliable exploitation of Cisco routers difficult. With approximately 300,000 unique IOS images in existence, a new class of version‐agnostic shellcode is needed in order to make the large‐scale exploitation of Cisco IOS possible. The purpose of this paper is to show that such attacks are now feasible by demonstrating two different reliable shellcodes that will operate correctly over many Cisco hardware platforms and all known IOS versions.

Design/methodology/approach

The paper examines prior work in the area of Cisco IOS rootkits and constructs a novel IOS version‐agnostic rootkit called the interrupt‐hijack rootkit.

Findings

As the experimental results show, the techniques proposed in this paper can reliably inject command and control capabilities into arbitrary IOS images in a version‐agnostic manner.

Originality/value

The authors believe that the technique presented in this paper overcomes an important hurdle in the large‐scale, reliable rootkit execution within Cisco IOS. Thus, effective host‐based defence for such routers is imperative for maintaining the integrity of our global communication infrastructures.
Student nurses’ experiences of support in relation to suicide or suicidal behaviours of mental health patients: an exploratory study
Authors: Phillips Louise , Tannis‐Ellick Stephanie , Scott Betsy
Published: July 2013

Purpose

Observations have been made that mental health students receive very little support following observing patients displaying suicidal behaviour. The purpose of this paper is to conduct a small‐scale empirical study to investigate this issue further.

Design/methodology/approach

The approach used in this study is phenomenological. Qualitative data were obtained through semi‐structured interviews consisting of a range of questions asking mental health student nurses about their experiences of support in practice. The data are analysed using thematic analysis.

Findings

As well as issues relating to the support of mental health student nurses in practice, there are many ethical issues raised in this paper. These include student responsibilities while in placement areas; students as having a supernumerary status; and the inclusion of students in supervision and debriefing sessions following traumatic incidents.

Research limitations/implications

This small‐scale exploratory study was conducted with a small number of students in one University. However, the study provides a strong starting point for further research on the support students receive during their mental health nurse training.

Originality/value

This paper makes some recommendations on ways to improve the support of students in practice, including maintaining and supporting the role of Practice Experience Managers who spend a considerable amount of time in placement areas interacting with students and feeding back relevant practice concerns to University staff.
Developing inclusive environments in mental health provision for people with disabilities
Authors: Whitehead Graham , Barnard Adam
Published: July 2013

Purpose

The increased use of mental health interventions employing cognitive behavioural therapy (CBT) over the last decade raises the significant theme of the efficacy of such treatments for people with disabilities. Recent evidence‐based studies regarding the application of cognitive behavioural interventions for people with disabilities have highlighted issues concerning access to services, questions of engagement and efficacy of the cognitive aspects of CBT practice and service models and forms of delivery. The purpose of this paper is to explore these themes with particular emphasis on barriers to accessibility for this population and provide consideration of ethical and effective practice aspects of psychological interventions in response to the recent World Health Organisation recommendations on disability provision.

Design/methodology/approach

The paper considers the development of the “enabling environments” theme for people with disabilities within a mental health context within Europe, with a view to exploring barriers to social inclusion and service user autonomy. The paper is designed to review and enhance existing literature in the field and to question the philosophical position of cognitive‐behavioural approaches to mental health provision in a European context.

Findings

Consideration is given to the use and application of CBT and evidence‐based practice (EBP) and considers efficacy in mental health provision for this population. Consideration is also given to the efficacy and appropriateness of short‐term interventions for this population.

Research limitations/implications

As a conceptual paper, the limitations of the discussion are that the views expressed are solely those of the authors but the paper usefully develops consideration of the existing literature in the field and discusses the implications of developing inclusive practice in mental health provision for this population.

Practical implications

The issues discussed in the paper offer significant questions relevant to the delivery of mental health provision for people with disabilities from a European perspective. Practical implications relate to the development of inclusive practice for practitioners in the delivery of these services.

Social implications

The social implications of the paper are significant, as the issues discussed raise questions about how mental health services approach their provision for people with disabilities. From a social context, the conceptual discussion offers insights useful to develop effective mental health provision and promote service user responsibility and autonomy.

Originality/value

As a conceptual paper, the originality of the submission relates to questioning the efficacy of more recent developments in the mental health field re: philosophy of approach and method and recommendations are offered by the authors which may impact service delivery, the focus of relevant evidence‐based practice and service user autonomy.