bluuebunny/crossref_metadata_2025 huggingface dataset:
How Can We Teach Them about Neurotrauma Prevention? Prospective and Randomized “Pense Bem—Caxias do Sul” Study with Multiple Interventions in Preteens and Adolescent
Authors: Falavigna S. Asdrubal , Medeiros Gregory , Canabarro Carolina , Bossardi Julia Bertholdo , Teles Alisson Roberto , da Silva Pedro Guarise
Published: May 2015

Introduction

A previous study published by the authors showed that a single intervention could not change the base line attitudes toward neurotrauma prevention. The present study was designed to evaluate the effectiveness of multiple interventions in modifying knowledge and attitudes for the prevention of neurotrauma in Brazilian preteens and adolescents.

Materials and Methods

In a randomized controlled trial, fifth-year primary school (PS) and second-year high school (HS) students were divided into a control and two intervention (single/multiple) groups. The study was conducted in the following eight stages: T1, questionnaire to measure baseline characteristics; T2, lecture on trauma prevention; T3, reapplying the questionnaire used in T1; T4, Traffic Department intervention; T5, a play about trauma and its consequences; T6, Fire Department intervention; T7, Emergency Medical Service intervention; and T8, reapplying the questionnaire used in T1 and T3. Positive answers were considered those stating that safety devices were used “always or sometimes” and negative as “never” using safety devices.

Results

The sample consisted of 535 students. Regarding attitudes, students in all the groups at any stage of measurement showed protective behavior more than 95% of the time about seat belt use. There were only differences between attitudes in PS and HS students on T8 assessment concerning the use of safety equipment on bikes in the multiple intervention group and concerning the use of safety equipment on skateboards and rollerblades in single- and multiple-intervention groups. These differences were caused mainly by the reduction in positive answers by the HS group, rather than by the increase in positive or protective answers by the PS group. However, there was no difference when the control and intervention groups were compared, independent of the attitudes or the student groups studied. The most important reason for not using protective devices was the belief that they would not get hurt.

Conclusion

Multiple and different types of educational interventions, such as lectures, scenes from plays about trauma and its consequences, traffic and fire department intervention, and medical emergency intervention directed to preteens and adolescents from public and private schools did not modify most students' attitudes toward injury prevention. Clinical trial registration no was U1111–1121–0192 (National System of Ethics and Research in Brazil).
Motor Outcome and Histological Findings in a Clipping Model of Spinal Cord Injury: Comparison between Posterior and Lateral Clip Placement
Authors: Falavigna Asdrubal , Finger Guilherme , Sebben Cesar , da Silva Pedro Guarise , Conzatti Lucas Piccoli , Peletti-Figueró Manuela
Published: May 2015

Introduction

Different types of spinal cord injury models in rats were described in the literature, including spinal cord clip compression. This type of procedure can be performed by placing the clip in two directions in relation to the spinal cord: lateral or posterior. Studies published in the literature usually do not describe the direction of the clip placement. It is assumed that the severity of neurological symptoms and the histological lesion are different from each other in these two models. The objective is to evaluate the locomotor and the histological impact on the spinal cord comparing lateral and posterior clip placement.

Materials and Methods

This study is a randomized experimental trial. A total of 20 female Wistar rats, ranging from 250 to 300 g, aged 12 to 14 weeks, were randomized in two groups by the direction of clip placement: lateral group ( n = 10) and posterior group ( n = 10). After exposing the thoracic segment of spine (T8–T10), a laminectomy was performed at the T9 level under microscope view. The spinal cord injury was made using a 5 mm long aneurismal clip with a closing pressure of 50 g. Locomotor behavior was evaluated by the Basso, Beattie, and Bresnahan scale at the 1st, 7th, 14th, 21st, and 28th day after surgery and the histological analysis of the injury area by computer software.

Results

The histological evaluation showed a greater lesion area in the lateral group, mean 2.3 ± 2 mm2, when compared with the posterior group, mean 4.8 ± 1 mm2 ( p = 0.03). There was no overall difference between lateral and posterior locomotor scores from day 1 to 28 ( p = 0.361).

Conclusion

The lesion area observed in the spinal cord histology after the lateral placement of a clip was significantly greater than in the posterior direction of the clip. There was no overall motor performance difference between lateral and posterior BBB scores.
Evaluation of Protocols for Use of Hyperbaric Therapy for Functional Recovery in Rats with Spinal Cord Injury
Authors: Falavigna Asdrubal , da Silva Pedro Guarise , Conzatti Lucas Piccoli , Rizkalla Elisa Braun , Peletti-Figueró Manuela
Published: May 2015

Introduction

Currently, the recovery of neurological functions after spinal cord injury (SCI) still relies on the host's neural plasticity and compensatory mechanisms. Unfortunately, many of these patients are permanently paralyzed. The objective of this study is to analyze the efficacy of hyperbaric therapy (HT) on the motor recovery process and define the best protocol of treatment.

Materials and Methods

Experimental study with 48 Wistar that was performed following the University standards advocated by the Ethics Committee. The SCI was simulated by performing a laminectomy at the T8–T10 level using a surgical microscope (DF Vasconcelos, RJ, Brazil) and subsequent SCI by a falling object weighing 5 g, controlled by the IMPACTOR equipment (MASCIS Impactor, New Jersey, United States). The drop height was 12.5 mm (mild) ( n = 8) or 25 mm (moderate) ( n = 8) as they were the models most used in the literature. Motor recovery was assessed by the scale of Basso, Beattie, and Bresnahan (BBB) on days 1, 3, 7, 14, 21, and 28 postoperative (PO). The first phase of the study was the comparison between the two models of SCI. In the second step, 32 rats were subjected to SCI, and were divided into five protocols using HT with a hyperbaric oxygen chamber held at a pressure of 2.5 atmospheres for 1 hour: Control (SCI only), 12H (SCI 12 hours PO in a single session), 12H7D (SCI 12 hours and PO once daily for 7 days), 30 MIN (SCI 30 minutes PO in a single session), 30MIN7D (SCI 30 minutes and PO once daily for 7 days). The comparison between the scores of the BBB test was performed using the one way ANOVA + Tukey HSD. Significance was p < 0.05.

Results

By comparing the curves of motor recovery between rats with mild and moderate SCI, the average BBB in mild SCI was higher than in the moderate group only on days 3 and 7 PO. There was no statistically significant difference between the models in relation to the final motor outcome. The HBT group had a BBB significantly higher than the control group ( p = 0.001) on days 1, 3, 14, and 28 PO. The best HT protocol was the 30MIN7D p = 0.03 when compared with control on day 28.

Conclusion

There is no difference in the final outcome after 28 days PO between the light and moderate SCI in rats. Using HT accelerates motor recovery and improves motor outcome of rats. The best HT protocol is 30 minutes and after PO daily for 7 days.
Posterior and Anterolateral Surgical Approach for C2 Dumpbell-Shaped Cervical Neurinomas
Authors: Falavigna Asdrubal , Righesso Orlando , Volquind Daniel
Published: May 2015

Introduction

The treatment of hourglass-shaped neurinomas of the C2 root is surgical, using various approaches such as the posterior, posterolateral, anterior, or combined ones. There are controversies in the literature regarding the choice of the best surgical access aiming to remove the tumor completely and safely and maintaining the stability of the spine. This study reports the authors' experience with 14 hourglass-shaped neurinomas of the C2 root, comparing the posterior and anterolateral approaches.

Patients and Methods

A total of 14 patients with hourglass-shaped neurinoma of the cervical root of C2 were surgically treated. The analysis involved symptoms, radiological diagnosis, information about surgery, and postoperative outcome. The posterior approach was used to remove the tumors in nine patients, and the anterolateral one in five patients. The 10 steps and tips/tricks for safe surgical removal are identified and reported.

Results

Females predominated in this sample ( n = 8) and the mean age was 52 ± 4.16 years. The time from onset of the symptoms to diagnosis was 17.8 months ( ± 7.8 months). The mean surgical time was 180 minutes ( ± 39.15 minutes) in the posterior approach and 192 minutes ( ± 22.17 minutes) in the anterolateral approach ( p = 0.52). There was no statistically significant difference in the volume of intrasurgical bleeding among the groups (posterior approach: 70.71 ± 16.93; anterolateral approach: 65.00 ± 24.15; p = 0.64). The tumor was completely resected in all the patients. A complication occurred with the posterior access, which was the presence of a cerebrospinal fluid fistula, and it was necessary to reoperate, reconstructing the duramater with fascia lata.

Conclusion

The tumor was completely resected with both surgical approaches, but the posterior approach has the advantage of being more familiar to the surgeon.
Concomitant Dermoid Cysts of Conus Medullaris and Cauda Equina
Authors: Falavigna Asdrubal , Righesso Orlando , Hauschild Luis , Scatola Fernanda
Published: May 2015

Introduction

Spinal dermoid cysts are benign tumors that results from congenital or acquired ectodermal inclusion. These tumors account for 0.8 to 1.1% of all primary spinal tumors with the majority occurring in the extramedullary area mainly in the pediatric population. We present a rare case of an adult woman with two separate dermoid cysts in the cauda equina and conus medullaris. The literature concerning dermoids is also reviewed focusing on tumor etiopathogenesis. Patient and Methods: We report a case of 35-year-old woman who presented with chronic low back pain and left ciatalgia. She had a history of two abdominal surgeries to treat chronic constipation with an intraoperative diagnosis of intestinal adhesions. No history of spinal trauma, surgery, or lumbar puncture was reported. Neurological examination revealed hypoesthesia in the lateral surface of the left leg, weakness on dorsiflexion of the left foot, and Lasègue sign on the left leg. The magnetic resonance imaging evidenced a large mass located at the cauda equina and a smaller mass located at the conus medullaris. The literature was reviewed in PubMed. Surgical resection was accomplished through a posterior midline incision exposing L2 to S2. The histological examination of the tumors in cauda equina and conus yielded a diagnosis of dermoid cysts. Postoperatively, the patient had urinary retention which reverted in 2 months. Follow-up at 4 years showed complete resolution of preoperative symptoms.

Results

Our case is interesting because the adult patient with chronic low back and leg pain and intestinal dysfunction presented with two distinct dermoids located in the lumbosacral region. The patient had no history of spinal manipulation or trauma or any sign of dysraphism on physical and image examinations. Although the most common spinal localization is in the lumbosacral region, a concomitance of two separate tumors had never been reported in the literature to the best of our knowledge.

Conclusion

Spinal dermoid cysts are rare tumors that results from congenital or acquired implantation of embryogenic cells in the spinal canal. We do not know the origin of the two tumors in the presented case, they may have developed from two different embryogenic cells during fetal development or may have been secondary to a possible past cyst rupture whose contents spread to the conus medullaris. Total tumor removal should be the goal for preventing cystic recurrence and future malignization.
A New Entry Point and Trajectory for Iliac Bolt Fixation in Patients Undergoing Long Fusion to the Sacrum
Authors: Enercan Meric , Kahraman Sinan , Gokcen Bahadir , Sanli Tunay , Ozturk Cagatay , Alanay Ahmet , Alanay Azmi
Published: May 2015

Introduction

Osteotomy of the posterior superior iliac spine for preparation of traditional iliac screw entry point exposes the cancellous bone of the inner ilium and causes loss of circumferential cortical starting point which may compromise biomechanical stability. For this reason, traditional iliac screws may not provide the desired primary stability especially in osteopenic and osteoporotic patients. We describe a new free-hand technique with a starting point located at the posterior inferior iliac spine (PIIS), which does not require any decortication for entry and courses very close to the rigid subcortical bone over sciatic notch while providing a low profile fixation and easier connection with S1 screw. The aim of this study is to evaluate the result of this new iliac bolt fixation technique.

Patients and Methods

A total of 26 patients (21 F and 5 M) having lumbopelvic fixation with the new technique were reviewed. The new entry point is located at the midpoint of PIIS. Lateral cortex of distal iliac wing is exposed subperiosteally and sciatic notch was palpated for safe trajectory. Screw trajectory is intended to be parallel to the outer cortex of ilium, passing 1 to 1.5 cm above the sciatic notch. PIIS provides a rigid circumferential cortical starting point for entrance and trajectory through thick cortical iliac bone over sciatic notch which provides very strong screw purchase even in osteopenic and osteoporotic spine. New entry point also enables easier connection to S1 screw. Free-hand technique eliminates radiation exposure. Pre-op, post-op, and follow-up X-rays were reviewed for the radiological data.

Results

Mean age was 63.6 years (range, 19–84 years) and mean follow-up was 14 months (range, 12–18 months). Mean screw length was 93.46 mm (range, 80–110 mm). Screw diameters were 8.5 mm in 22 patients and 7.5 mm in 4 patients. Lumbosacral fusion was achieved in all the cases. There were no neurovascular injuries related to the sciatic nerve and gluteal artery during screw placement. There were no implant failures or screw breakage at end of final follow-up.

Conclusion

This new technique seems to be a viable option in patients undergoing fusion to the sacrum for iliac bolt fixation. PIIS provides a circumferential cortical starting point and low profile fixation with stronger screw purchase especially in osteoporotic patients.
Is Dynesys a Good Device for Motion Preservation and Prevention of Idiopathic Unstable after Decompression Surgery
Authors: Chang Chih-Ju
Published: May 2015

Introduction

The Dynesys dynamic stabilization system was first implanted in patients in 1994 in an attempt to overcome the drawbacks of fusion. It is supposed to preserve motion at the treat levels, while avoiding hypermobility and thus spondylosis at the adjacent levels. The aim of this retrospective study is to investigate the clinical outcome and the effect of preservation of ROM and developed instability after decompression surgery.

Patients and Methods

A total of 30 patients were treated with Dynesys between August 2008 to March 2014. The diagnosis included degenerative spinal stenosis, severe spinal stenosis with HIVD, huge intervertebral herniated disc, or recurrent HIVD. Back pain and leg pain were evaluated using visual analog scale (VAS). The Oswestry Disability Index (ODI) was used to evaluate the patient's function. The range of motion at the operative level and whole lumbar spine were measured on preoperative and postoperative radiographs.

Results

All the patients were followed up for 3 to 96 months (mean, 26.33 ± 25.3 months). Overall, 87 segments were applied in 30 patients. The mean age of the patients was 49.5 ± 10.4 years (range, 22–67 years). There were 19 male and 11 female patients, with slightly male predominant. VAS of leg pain, lower back pain, and the ODI were significantly improved postoperatively. There was a significant difference in the range of motion at the operative levels and the whole spine. The mean range of motion of whole spine was 28.89 ± 15.3 degrees preoperatively and 16.29 ± 8.39 degrees postoperatively, with 43.61% loss. The range of motion of operative levels were 12.01 ± 7.73 degrees preoperatively and 4.03 ± 3.19 degrees postoperatively, with 66.44% loss. There were four broken screws and no screws loosening were noted. No developed unstable conditions occurred and no cases need revision surgery in our study.

Conclusion

The preliminary results of Dynesys for lumbar degenerative stenosis with/without HIVD in our series are similar to the published results of the previous literature. It can significantly improve the clinic symptoms and signs. And the Dynesys device is a semirigid fixation system for the stabilization of lumbar degenerative disease. We think the role of Dynesys is a device to delay the nature decade of lumbar spine and prevent the possibility of idiopathic unstable after decompression surgery. So, the indication of the Dynesys should seriously restriction of the age. It should be used in the patients with no or mild unstable condition, and it is better in the younger patients. But the true effect should depend on longer follow-up.
Characterization of the Thoracolumbar Injury in Traumatic Spinal Service; UMAE Hospital “Dr. Victorio de la Fuente Narvaez” during the Period 2004 to 2009
Authors: Casas Gustavo , Marquez García Edgar Abel , Tavizon Salazar Aaron
Published: May 2015

Background

The daily thoracolumbar fractures become more frequent and more severe because of the high urbanization and labor requirements is subject to the individual. Thoracolumbar spine injuries are of great importance for themselves, leaving a high morbidity, that is, residual functional disability leave despite its correction. Usually, a thoracolumbar injury, usually involving several segments, primarily affects the individual in the third and fourth decade of life, period of highest risk in the individual economically productive. Unfortunately, the prevalence of these lesions is subject to the presence of economic, cultural, demographic, without reports that reflect the reality etiology of these fractures thoracolumbar. Research Question: What are the characteristics and incidence of thoracolumbar fractures in UMAE Hospital Dr. Victorio de la Fuente Narváez during the period 2004 to 2009?

Objective

This study aims to identify the characteristics and incidence of thoracolumbar fractures in UMAE Hospital Dr. Victorio de la Fuente Narváez during the period 2004 to 2009.

Methods

We reviewed all the records and medical records of patients seen during the years 2004 to 2009 with a diagnosis of thoracolumbar fractures, which have been treated at the Hospital UMAE Dr. Victorio de la Fuente Narváez and have required hospitalization. Data will be collected in catch sheet specially designed for this protocol (Appendix 1) emptying the information later in the database in Excel to perform estimates, final graphics performance.

Results

A total of 1,102 patients in the period from January 1, 2004 to December 31, 2009 which met the criteria of this research are the study sample. Of which, 754 (69%) were male and 345 (31%) were female. As the incidence is reported according to the copyright holder population aged 15 years, the unit per year was 1,361,122 in 2004; 1,841,004 in 2005; 1,871,122 in 2006; 1,989,014 in 2007; 2,345,379 in 2008; and 2,375,893 in 2009. Its average incidence was 8.71 per 100,000 population most affected segment was lumbar 712: 345 followed by thoracic, thoracolumbar 38, and 7 mixed. The most common levels were L1 397, L2 215, T12 63, L3 95, L4 76, T11 48, and T5 40. The most frequent type according to AO classification were: In 618 cases, 255 cases B, C 194 cases, and firearm injuries (PAF) 28 cases. Mixed (A + B, A + C, and B + C) seven cases. The most common subtype according to the AO classification was B1.2 (128), followed by A3.1 (108), the neurological condition are presented in this series, with complete neurological injury Frankel A 184, with partial neurological injury Frankel B 13, C 26 Frankel, Frankel D 43; and neurlogica unaffected Frankel E 834.
Posterior Traumatic Atlantoaxial Subluxation: A Case Report
Authors: Cahueque Mario
Published: May 2015

Introduction

Injuries to the cervical spine are often described as neurologically catastrophic events with a very low survival rate. Lesions of the C3–C7 segment are the most common (∼ 80%) followed by the segment C1–C2 (20%). Injuries to the cervical spine are of great importance, both for its severity as well as the neurological implications they entail. The delay in diagnosis and treatment has been reported as a negative prognostic factor associated with poor outcome. Cases of atlantoaxial dislocations have been reported without neurological deficit at presentation and in long-term follow-up so these injuries could be unnoticed at the emergency department. When neurological damage is not evident at presentation symptoms are generally unspecific, such as, suboccipital pain when axial cranial pressure is applied movement, or at passive rotation the patient spontaneously assumes a stiff neck, contracting sternocleidomastoid and trapezius muscles.

Materials and Methods

A 28-year-old male patient without relevant medical history was a victim of physical assault on August 15, 2012, suffering cranial and cervical trauma, and was discharged, he showed no neurological symptoms then. Six weeks after discharge, he began with paresthesias of thoracic limbs and subsequently with diminished muscle strength, which was gradually decreasing. Imaging demonstrated atlantoaxial subluxation. Posterior instrumentation with transfacetary lag screws at C1/C2 was performed. Results One year after surgery, the patient presents without neurological deficit, absence of stiff neck and denies pain when mobilization of the neck or axial compression is applied. Fusion was achieved with no further complications.

Conclusion

The diagnosis of traumatic subluxation should be suspected in the presence of torticollis and neck pain associated with cervical trauma. However, atlantoaxial dislocation can occur in the absence of any clinical signs so it should be systematically considered as a diagnosis an should be excluded in any polytraumatized. We suggest that simple radiographic measurements (ADI and Powers Index). When the instability of the C1/C2 joint is diagnosed, early reduction, and fusion is recommended as the definitive treatment.
Pressure-induced polymerization of P(CN)3
Authors: Gou Huiyang , Yonke Brendan L. , Epshteyn Albert , Kim Duck Young , Smith Jesse S. , Strobel Timothy A.
Published: May 2015

Motivated to explore the formation of novel extended carbon-nitrogen solids via well-defined molecular precursor pathways, we studied the chemical reactivity of highly pure phosphorous tricyanide, P(CN)3, under conditions of high pressure at room temperature. Raman and infrared (IR) spectroscopic measurements reveal a series of phase transformations below 10 GPa, and several low-frequency vibrational modes are reported for the first time. Synchrotron powder X-ray diffraction measurements taken during compression show that molecular P(CN)3 is highly compressible, with a bulk modulus of 10.0 ± 0.3 GPa, and polymerizes into an amorphous solid above ∼10.0 GPa. Raman and IR spectra, together with first-principles molecular-dynamics simulations, show that the amorphization transition is associated with polymerization of the cyanide groups into CN bonds with predominantly sp2 character, similar to known carbon nitrides, resulting in a novel phosphorous carbon nitride (PCN) polymeric phase, which is recoverable to ambient pressure.
Quantum process tomography by 2D fluorescence spectroscopy
Authors: Pachón Leonardo A. , Marcus Andrew H. , Aspuru-Guzik Alán
Published: May 2015

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.
Impact of inward turbulence spreading on energy loss of edge-localized modes
Authors: Ma C. H. , Xu X. Q. , Xi P. W. , Xia T. Y. , Snyder P. B. , Kim S. S.
Published: May 2015

Nonlinear two-fluid and gyrofluid simulations show that an edge localized modes (ELM) crash has two phases: fast initial crash of ion temperature perturbation on the Alfvén time scale and slow turbulence spreading. The turbulence transport phase is a slow encroachment of electron temperature perturbation due to the ELM event into pedestal region. Because of the inward turbulence spreading effect, the energy loss of an ELM decreases when density pedestal height increases. The Landau resonance yields the different cross phase-shift of ions and electrons. A 3 + 1 gyro-Landau-fluid model is implemented in BOUT++ framework. The gyrofluid simulations show that the kinetic effects have stabilizing effects on the ideal ballooning mode and the energy loss increases with the pedestal height.
Anharmonicity and necessity of phonon eigenvectors in the phonon normal mode analysis
Authors: Feng Tianli , Qiu Bo , Ruan Xiulin
Published: May 2015

It is well known that phonon frequencies can shift from their harmonic values when elevated to a finite temperature due to the anharmonicity of interatomic potential. Here, we show that phonon eigenvectors also have shifts, but only for compound materials in which each atom has at least two types of anharmonic interactions with other atoms. Using PbTe as the model material, we show that the shifts in some phonon modes may reach as much as 50% at 800 K. Phonon eigenvectors are used in normal mode analysis (NMA) to predict phonon relaxation times and thermal conductivity. We show, from both analytical derivations and numerical simulations, that the eigenvectors are unnecessary in frequency-domain NMA, which gives a critical revision of previous knowledge. This simplification makes the calculation in frequency-domain NMA more convenient since no separate lattice dynamics calculations are needed. On the other hand, we expect our finding of anharmonic eigenvectors may make difference in time-domain NMA and other areas, like wave-packet analysis.
Exact analytical solutions of the Schrödinger equation for the nine-dimensional MICZ-Kepler problem
Authors: Nguyen Thanh-Son , Le Dai-Nam , Thoi Tuan-Quoc N. , Le Van-Hoang
Published: May 2015

The nine-dimensional MICZ-Kepler problem has been established recently as a system describing the motion of a nine-dimensional charged particle in the Coulomb potential with the presence of the SO(8) monopole. Interestingly, this is the last case of dimension in which the MICZ-Kepler problem is equivalent to a harmonic oscillator via generalized Hurwitz transformation. In this work, exact analytical solutions of the Schrödinger equation for the nine-dimensional MICZ-Kepler problem are successfully built for the first time and the degeneration degree of the energy is also calculated.
Explicitly correlated ring-coupled-cluster-doubles theory
Authors: Hehn Anna-Sophia , Tew David P. , Klopper Wim
Published: May 2015

The connection between the random-phase approximation and the ring-coupled-cluster-doubles method bridges the gap between density-functional and wave-function theories and the importance of the random-phase approximation lies in both its broad applicability and this linking role in electronic-structure theory. In this contribution, we present an explicitly correlated approach to the random-phase approximation, based on the direct ring-coupled-cluster-doubles ansatz, which overcomes the problem of slow basis-set convergence, inherent to the random-phase approximation. Benchmark results for a test set of 106 molecules and a selection of 10 organic complexes from the S22 test set demonstrate that convergence to within 99% of the basis-set limit is reached for triple-zeta basis sets for atomisation energies, while quadruple-zeta basis sets are required for interaction energies. Corrections due to single excitations into the complementary auxiliary space reduce the basis-set incompleteness error by one order of magnitude, while contributions due to the coupling of conventional and geminal amplitudes are in general negligible. We find that a non-iterative explicitly correlated correction to first order in perturbation theory exhibits the best ratio of accuracy to computational cost.
Tunneling spectroscopy of Al/AlOx/Pb subjected to hydrostatic pressure
Authors: Zhu Jun , Yang Zheng-Xin , Hou Xing-Yuan , Guan Tong , Zhang Qin-Tong , Li Yong-Qing , Han Xiu-Feng , Zhang Jin , Li Chun-Hong , Shan Lei , Chen Gen-Fu , Ren Cong
Published: May 2015

We develop an experimental tool to investigate high-pressure electronic density of state by combining electron tunneling spectroscopy measurements with high-pressure technique. It is demonstrated that tunneling spectroscopy measurement on Al/AlOx/Pb junction is systematically subjected to hydrostatic pressure up to 2.2 GPa. Under such high pressure, the normal state junction resistance is sensitive to the applied pressure, reflecting the variation of band structure of the barrier material upon pressures. In superconducting state, the pressure dependence of the energy gap Δ0, the gap ratio 2Δ0/kBTc, and the phonon spectral energy is extracted and compared with those obtained in the limited pressure range. Our experimental results show the accessibility and validity of high pressure tunneling spectroscopy, offering wealthy information about high pressure superconductivity.
Explosive magnetic reconnection caused by an X-shaped current-vortex layer in a collisionless plasma
Authors: Hirota M. , Hattori Y. , Morrison P. J.
Published: May 2015

A mechanism for explosive magnetic reconnection is investigated by analyzing the nonlinear evolution of a collisionless tearing mode in a two-fluid model that includes the effects of electron inertia and temperature. These effects cooperatively enable a fast reconnection by forming an X-shaped current-vortex layer centered at the reconnection point. A high-resolution simulation of this model for an unprecedentedly small electron skin depth de and ion-sound gyroradius ρs, satisfying de=ρs, shows an explosive tendency for nonlinear growth of the tearing mode, where it is newly found that the explosive widening of the X-shaped layer occurs locally around the reconnection point with the length of the X shape being shorter than the domain length and the wavelength of the linear tearing mode. The reason for the onset of this locally enhanced reconnection is explained theoretically by developing a novel nonlinear and nonequilibrium inner solution that models the local X-shaped layer, and then matching it to an outer solution that is approximated by a linear tearing eigenmode with a shorter wavelength than the domain length. This theoretical model proves that the local reconnection can release the magnetic energy more efficiently than the global one and the estimated scaling of the explosive growth rate agrees well with the simulation results.
Magnetostatic interactions between wire-tube nanostructures
Authors: Salazar-Aravena D. , Palma J. L. , Escrig J.
Published: May 2015

We have investigated the magnetostatic interactions between wire-tube nanostructures. We have observed that the coercivity of the array decreases when the distance between the nanostructures decreases. Besides, when the external magnetic field is applied along the axis of the nanostructures, the two Barkhausen jumps observed for an isolated wire-tube nanostructure give rise to several minor jumps for a weakly interacting array, which eventually become a single jump for the most interacting case. Additionally, the angle θ at which maximum coercivity is obtained varies as a function of the center-to-center distance between the nanostructures, while those remanences obtained for arrays with different distances between the nanostructures coincide. In this way, the study of magnetostatic interactions between wire-tube nanostructures is an interesting topic of research in connection with potential applications where it is usually desirable to avoid such interactions or at least control them.
Calcined Mg-Fe layered double hydroxide as an absorber for the removal of methyl orange
Authors: Peng Chao , Dai Jing , Yu Jianying , Yin Jian
Published: May 2015

In this work, methyl orange (MO) was effectively removed from aqueous solution with the calcined product of hydrothermal synthesized Mg/Fe layered double hydroxide (Mg/Fe-LDH). The structure, composition, morphology and textural properties of the Mg/Fe-LDH before and after adsorption were characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, nitrogen adsorption apparatus and X-ray photoelectron spectroscopy. It was confirmed that MO had been absorbed by calcined Mg/Fe-LDH which had strong interactions with MO. The adsorption of MO onto the Mg/Fe-LDH was systematically investigated by batch tests. The adsorption capacity of the Mg/Fe-LDH toward MO was found to be 194.9 mg • g−1. Adsorption kinetics and isotherm studies revealed that the adsorption of MO onto Mg/Fe-LDH was a spontaneous and endothermic process. These results indicate that Mg/Fe-LDH is a promising material for the removal of MO.
Nonlinear photoacoustic spectroscopy of hemoglobin
Authors: Danielli Amos , Maslov Konstantin , Favazza Christopher P. , Xia Jun , Wang Lihong V.
Published: May 2015

As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.
Response of Bighead Carp and Silver Carp to Repeated Water Gun Operation in an Enclosed Shallow Pond
Authors: Romine Jason G. , Jensen Nathan R. , Parsley Michael J. , Gaugush Robert F. , Severson Todd J. , Hatton Tyson W. , Adams Ryan F. , Gaikowski Mark P.
Published: May 2015

The Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix are nonnative species that pose a threat to Great Lakes ecosystems should they advance into those areas. Thus, technologies to impede Asian carp movement into the Great Lakes are needed; one potential technology is the seismic water gun. We evaluated the efficacy of a water gun array as a behavioral deterrent to the movement of acoustic-tagged Bighead Carp and Silver Carp in an experimental pond. Behavioral responses were evaluated by using four metrics: (1) fish distance from the water guns (D); (2) spatial area of the fish's utilization distribution (UD); (3) persistence velocity (Vp); and (4) number of times a fish transited the water gun array. For both species, average D increased by 10 m during the firing period relative to the pre-firing period. During the firing period, the spatial area of use within the pond decreased. Carp were located throughout the pond during the pre-firing period but were concentrated in the north end of the pond during the firing period, thus reducing their UDs by roughly 50%. Overall, Vp decreased during the firing period relative to the pre-firing period, as fish movement became more tortuous and confined, suggesting that the firing of the guns elicited a change in carp behavior. The water gun array was partially successful at impeding carp movement, but some fish did transit the array. Bighead Carp moved past the guns a total of 78 times during the pre-firing period and 15 times during the firing period; Silver Carp moved past the guns 96 times during the pre-firing period and 13 times during the firing period. Although the water guns did alter carp behavior, causing the fish to move away from the guns, this method was not 100% effective as a passage deterrent.

Received August 6, 2014; accepted January 16, 2015
Predation by American White Pelicans on Yellowstone Cutthroat Trout in the Blackfoot River Drainage, Idaho
Authors: Teuscher David M. , Green Matthew T. , Schill Daniel J. , Brimmer Arnold F. , Hillyard Ryan W.
Published: May 2015

Expansion of the American white pelican Pelicanus erythrorhynchos colony on Blackfoot Reservoir, Idaho, and the associated declines in adfluvial Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in the upper Blackfoot River drainage has generated concern about the impact of pelican predation on this native trout stock. During a 4-year study, 4,653 wild Yellowstone Cutthroat Trout were tagged using a combination of radiotelemetry and PIT tags. Annual predation rate estimates were made by recovering Yellowstone Cutthroat Trout tags from the nesting islands of American white pelicans. On-island tag recovery rates were corrected for ingested tags that went undetected during island searches and for tags that were deposited away from the nesting islands. American white pelicans consumed tagged Yellowstone Cutthroat Trout ranging from 150 mm to 580 mm TL and showed no size selection within that range for their prey. Predation rates on adult and juvenile Yellowstone Cutthroat Trout generally exceeded 20%, and the highest values were above 60%. Our independent methods (telemetry and PIT tagging) for estimating pelican predation on adult Yellowstone Cutthroat Trout produced similar results. Annual river flow conditions varied markedly and may have contributed to some of the observed range in predation rate estimates. Predation by the pelican colony appears to be a likely contributor to the recent collapse of Yellowstone Cutthroat Trout in the upper Blackfoot River drainage. In the past, overexploitation by anglers severely reduced the trout population and was remedied by implementing catch-and-release regulations. The current predation impact poses a greater management challenge, namely, finding a balanced approach for conserving both the native trout stock and the pelican colony.

Received April 29, 2014; accepted February 5, 2015
An Evaluation of the Efficiency of Minnow Traps for Estimating the Abundance of Minnows in Desert Spring Systems
Authors: Peterson James T. , Scheerer Paul D. , Clements Shaun
Published: May 2015

Desert springs are sensitive aquatic ecosystems that pose unique challenges to natural resource managers and researchers. Among the most important of these is the need to accurately quantify population parameters for resident fish, particularly when the species are of special conservation concern. We evaluated the efficiency of baited minnow traps for estimating the abundance of two at-risk species, Foskett Speckled Dace Rhinichthys osculus ssp. and Borax Lake Chub Gila boraxobius, in desert spring systems in southeastern Oregon. We evaluated alternative sample designs using simulation and found that capture–recapture designs with four capture occasions would maximize the accuracy of estimates and minimize fish handling. We implemented the design and estimated capture and recapture probabilities using the Huggins closed-capture estimator. Trap capture probabilities averaged 23% and 26% for Foskett Speckled Dace and Borax Lake Chub, respectively, but differed substantially among sample locations, through time, and nonlinearly with fish body size. Recapture probabilities for Foskett Speckled Dace were, on average, 1.6 times greater than (first) capture probabilities, suggesting “trap-happy” behavior. Comparison of population estimates from the Huggins model with the commonly used Lincoln–Petersen estimator indicated that the latter underestimated Foskett Speckled Dace and Borax Lake Chub population size by 48% and by 20%, respectively. These biases were due to variability in capture and recapture probabilities. Simulation of fish monitoring that included the range of capture and recapture probabilities observed indicated that variability in capture and recapture probabilities in time negatively affected the ability to detect annual decreases by up to 20% in fish population size. Failure to account for variability in capture and recapture probabilities can lead to poor quality data and study inferences. Therefore, we recommend that fishery researchers and managers employ sample designs and estimators that can account for this variability.

Received September 29, 2014; accepted January 29, 2015
Relevance drives attention: Attentional bias for gain- and loss-related stimuli is driven by delayed disengagement
Authors: Müller Sascha , Rothermund Klaus , Wentura Dirk
Published: May 2015

Attentional bias to gain- and loss-related stimuli was investigated in a dot-probe task. We used coloured stimuli that had acquired their valence during the experiment by signalling the chance to either win or lose points in a game task. Replicating previous findings with the additional singleton paradigm, we found attentional bias effects for both gain- and loss-related colours. The effects were due to delayed disengagement from valent stimuli, especially if they were positive, and could not be explained by nonattentional processes like behavioural freezing. Our findings suggest that stimuli signalling opportunities and dangers hold attention, supporting a general motivational relevance principle of the orienting of attention.
Trends in use of genotypic resistance testing and frequency of major drug resistance among antiretroviral-naive persons in the HIV Outpatient Study, 1999–2011
Authors: Buchacz Kate , Young Benjamin , Palella Frank J. , Armon Carl , Brooks John T. ,   on behalf of the HIV Outpatient Study (HOPS) investigators, Buchacz Kate , Brooks John T. , Durham Marcus D. , Hays Harlen , Wood Kathleen C. , Hankerson Darlene , Hart Rachel , Subramanian Thilakavathy , Armon Carl , Dean Bonnie , Franklin Dana , Palella Frank J. , Chmiel Joan S. , Jahangir Saira , Flaherty Conor Daniel , Dixon-Evans Jerian Denise , Lichtenstein Kenneth A. , Stewart Cheryl , Hammer John , Greenberg Kenneth S. , Widick Barbara , Franklin Rosa , Yangco Bienvenido G. , Chagaris Kalliope , Ward Doug , Fuhrer Jack , Ording-Bauer Linda , Kelly Rita , Esteves Jane , Tedaldi Ellen M. , Christian Ramona A. , Ruley Faye , Beadle Dania , Graham Princess , Novak Richard M. , Wendrow Andrea , Smith Renata , Young Benjamin , Widick Barbara , Scott Mia
Published: May 2015

Background

Monitoring antiretroviral drug resistance can inform treatment recommendations; however, there are few such data from US patients before they initiate ART.

Methods

We analysed data from HIV Outpatient Study (HOPS) participants from nine US HIV clinics who were diagnosed with HIV infection during 1999–2011. Using the IAS-USA December 2010 guidelines, we assessed the frequency of major drug resistance mutations (mDRMs) related to antiretroviral agents in viral isolates from patients who underwent commercial genotypic testing (GT) for resistance before initiating ART. We employed general linear regression models to assess factors associated with having undergone GT, and then factors associated with having mDRM.

Results

Among 1531 eligible patients, 758 (49.5%) underwent GT before first ART, increasing from 15.5% in 1999–2002 to 75.9% in 2009–11 (P < 0.001). GT was carried out a median of 1.2 months after the diagnosis of HIV. In adjusted regression analyses, patients with pre-ART CD4+ T lymphocyte counts ≥200 cells/mm3 or with HIV RNA levels >5.0 log10 copies/mL and those with a first HOPS visit in 2006 or later were significantly (P < 0.05) more likely to have undergone GT. Of the 758 patients, 114 (15.0%) had mDRMs; mutations relating to NRTIs, NNRTIs and PIs were present in 8.0%, 7.1% and 2.6%, respectively. There was no temporal change in the frequency of mDRM, and mDRMs were associated with an HIV RNA level <4.0 log10 copies/mL.

Conclusions

During 1999–2011, GT use among antiretroviral-naive patients became more common, but a quarter of patients in recent years remained untested. The frequency of mDRMs remained stable over time at about 15%.
Native SAD is maturing
Authors: Rose John P. , Wang Bi-Cheng , Weiss Manfred S.
Published: May 2015

Native SAD phasing uses the anomalous scattering signal of light atoms in the crystalline, native samples of macromolecules collected from single-wavelength X-ray diffraction experiments. These atoms include sodium, magnesium, phosphorus, sulfur, chlorine, potassium and calcium. Native SAD phasing is challenging and is critically dependent on the collection of accurate data. Over the past five years, advances in diffraction hardware, crystallographic software, data-collection methods and strategies, and the use of data statistics have been witnessed which allow `highly accurate data' to be routinely collected. Today, native SAD sits on the verge of becoming a `first-choice' method for bothde novoand molecular-replacement structure determination. This article will focus on advances that have caught the attention of the community over the past five years. It will also highlight bothde novonative SAD structures and recent structures that were key to methods development.
Effects of shared vision and integrations on entrepreneurial performance
Authors: Chi-hsiang Chen
Published: May 2015

Purpose

– This paper aims to examine the possible benefits and effects of shared vision and integration on entrepreneurial management for new Chinese ventures. By examining new enterprises, rather than already established and operating firms, this study can better demonstrate the impact of shared vision and internal or external integration on entrepreneurial performance. The empirical analyses demonstrate the importance of shared vision and both types of integration for new ventures, particularly enterprises in China.

Design/methodology/approach

– This study collected data from firms in Greater China, including China, Taiwan and Hong Kong. Five hypotheses were tested, for which the total sample size was 246 respondents. Confirmatory factor analysis and structural equation modeling were applied for statistical analyses.

Findings

– The results indicate that entrepreneurial vision correlates positively with shared vision. In its turn, shared vision correlates positively with internal integration and external integration. Furthermore, internal integration correlates positively with entrepreneurial performance. Although external integration is essential during new enterprise establishment, analytical results indicate that external integration is not strongly correlated with entrepreneurial performance.

Practical implications

– Shared vision plays a critical role in the integration process during the establishment of new enterprises. The results of this study show that newly established firms need to put more efforts than do operating firms into integrating external resources.

Originality

– /

value

This study contributes to a better understanding of the effects of shared vision and the different kinds of integration on entrepreneurial management. Knowing the driving forces behind these phenomena may help new firms to engage more actively in resources integration and enhance their entrepreneurial performance.