bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing Young Hispanic Dual Language Learners' Achievement: Exploring Strategies and Addressing Challenges
Authors: Ackerman Debra J. , Tazi Zoila
Published: January 2015

Dual language learners, or DLLs, may have greater school readiness needs due to the key role English oral language skills play in the development of emerging literacy skills in English and their overall academic achievement. This especially can be the case if children's capacity to benefit from classroom instruction and interact with teachers and fellow students is dependent on their English language proficiency. This policy report examines key factors contributing to young Hispanic DLLs academically at‐risk status, as well as the emerging research base on strategies for supporting the learning and development of DLLs in preschool and the early primary grades. Also addressed are the practical, on‐the‐ground implementation challenges to be addressed if early education programs are to incorporate these strategies.
Fish peptone development using enzymatic hydrolysis of silver carp by‐products as a nitrogen source in Staphylococcus aureus media
Authors: Fallah Meysam , Bahram Somayeh , Javadian Seyed Roholla
Published: January 2015

Fish peptone was produced using enzymatic hydrolysis of silver carp filleting by‐products by alcalase and trypsin. Also, the efficiency of the hydrolysates as a nitrogen source in Staphylococcus aureus medium was compared with commercial TSB. The results indicated that the protein hydrolysate from alcalase and trypsin had high protein content (92.92%, 91.53 respectively), and degree of hydrolysis (4.94%, 4.6% respectively).The results showed that silver carp filleting waste can be an efficient source for fish peptone production as a nitrogen source for S. aureus medium. However, the type of the used proteolytic enzyme considerably affected the performance of the resulting peptone despite the same DH. Fish peptone produced by alcalese performed significantly (P < 0.05) better than commercial TSB as a media for the bacteria while the performance of the trypsin peptone was not as good as the commercial medium.
International Joint Ventures as Boundary Spanners: Technological Knowledge Transfer in an Emerging Economy
Authors: Khan Zaheer , Lew Yong Kyu , Sinkovics Rudolf R.
Published: January 2015

We investigate how international joint ventures (IJVs) established in emerging economies help their local suppliers with technological knowledge transfer. Data from 50 Pakistani‐owned Tier 1 suppliers, three of the major assemblers, and policy makers in the Ministry of Industries and Production in Pakistan is collected. Findings suggest that, in the context of the Pakistani emerging economy, IJVs can also play a critical role as the boundary spanners of knowledge transfer. Local suppliers are linked with their global suppliers' networks through associational learning. Social capital between the IJVs and the local component suppliers and the IJVs' willingness to initiate a knowledge transfer dialogue among local and global Tier 1 suppliers are critically important factors that enable this transfer.
The Use of Mentalization‐Based Treatment for Adolescents (MBT‐A) With a Young Woman With Mixed Personality Disorder and Tendencies to Self‐Harm
Authors: Rossouw Trudie I
Published: January 2015

This article explores the psychological profile and treatment of young people who present clinically with features of borderline and avoidant personality disorder, along with vulnerable narcissistic traits. Self‐harm in these youngsters is often used to regulate internal storms. It is argued that the adolescent phase of development is a trigger point for collapse in these vulnerable young people. In therapy, these patients are difficult to connect with emotionally and treatment can be fraught with strong countertransference reactions. A case study is used to illustrate the use of mentalization‐based treatment for adolescents for such individuals.
Conformational frustration in calmodulin–target recognition
Authors: Tripathi Swarnendu , Wang Qian , Zhang Pengzhi , Hoffman Laurel , Waxham M. Neal , Cheung Margaret S.
Published: January 2015

Calmodulin (CaM) is a primary calcium (Ca2+)‐signaling protein that specifically recognizes and activates highly diverse target proteins. We explored the molecular basis of target recognition of CaM with peptides representing the CaM‐binding domains from two Ca2+‐CaM‐dependent kinases, CaMKI and CaMKII, by employing experimentally constrained molecular simulations. Detailed binding route analysis revealed that the two CaM target peptides, although similar in length and net charge, follow distinct routes that lead to a higher binding frustration in the CaM–CaMKII complex than in the CaM–CaMKI complex. We discovered that the molecular origin of the binding frustration is caused by intermolecular contacts formed with the C‐domain of CaM that need to be broken before the formation of intermolecular contacts with the N‐domain of CaM. We argue that the binding frustration is important for determining the kinetics of the recognition process of proteins involving large structural fluctuations. Copyright © 2015 John Wiley & Sons, Ltd.
Recovery efficiency of nitrogen from liquid and solid fractions of pig slurry obtained using different separation technologies
Authors: Fangueiro David , Coutinho João , Borges Leandro , Vasconcelos Ernesto
Published: January 2015

The characteristics of solid (SF) and liquid (LF) fractions resulting from solid–liquid separation of pig slurry depend on the separation technique used. It can be assumed that the separation technique will also affect the nitrogen (N) availability to plants. A pot experiment was performed with ryegrass to compare the N‐recovery efficiency of SFs and LFs obtained with four frequently used separation techniques (centrifugation [Cent], sediment settling during 20 h [Sed], enhanced settling during 20 h by addition of cationic polyacrylamide [Sed+PAM], sieving [Siev], sieving followed by treatment of the resulting liquid fraction by PAM addition [Siev+PAM]) with the untreated slurry (US) and an unfertilized control. Increases (2–17%) of ryegrass dry matter yield (DMY) were obtained in LF treatments relative to US. However, this increase was statistically significant only for the Siev+PAM‐L treatment. A significant decrease of ryegrass DMY was observed in SF treatments relative to US. All treatments with SFs led to similar values of DMY while only small differences were observed between treatments receiving LFs. A significant correlation (R2 = 0.968) was observed between the total DMY and the NH$ _4^+ $ ‐ N : Ntot ratio of the fraction applied suggesting that this is a major parameter to be considered when comparing separation techniques. Overall, the separation techniques showed only a weak effect on the dry matter yields and on the N ‐ recovery efficiency from LF and SF although they strongly affected the nutrient concentration and speciation in each fraction.
Tephra analysis in ombrotrophic peatlands: A geochemical comparison of acid digestion and density separation techniques
Authors: ROLAND T. P. , MACKAY H. , HUGHES P. D. M.
Published: January 2015

Ombrotrophic peatlands often lack any substantial local mineral component and therefore present exceptional opportunities for the extraction and identification of tephra horizons. Following concerns of shard geochemistry alteration during isolation using acid digestion, an alternative methodology using heavy liquids has been proposed. However, harsh basic and acidic digestions are rarely required in organic‐rich, ombrotrophic peatlands. Consequently, this study tested for geochemical differences between tephra shards from a known rhyolitic eruption, isolated from the same stratigraphic depth of a peat sequence using density separation and an acid digestion methodology typically applied to ombrotrophic peat samples and analysed using electron probe microanalysis. Findings suggest that the two samples could not be geochemically distinguished using visual and statistical methods and that, in the context of rhyolitic tephras in ombrotrophic peats, acid digestion can be used without significant effects on the interpretation of results. Density separation may still be required in peatlands with high mineral input and further work is required to examine the effect of the acid digestion technique on tephra of non‐rhyolitic compositions.
Hydrological variability over the Apennines during the Early Last Glacial precession minimum, as revealed by a stable isotope record from Sulmona basin, Central Italy
Authors: REGATTIERI ELEONORA , GIACCIO BIAGIO , ZANCHETTA GIOVANNI , DRYSDALE RUSSELL N. , GALLI PAOLO , NOMADE SEBASTIEN , PERONACE EDOARDO , WULF SABINE
Published: January 2015

A multi‐proxy record was acquired from a Late Pleistocene lacustrine succession in the Sulmona basin, central Italy. Previous and new tephrostratigraphic analyses of six volcanic ash layers constrain the investigated interval to between 92.3 and 115.0 ka. The δ18O composition is interpreted as a proxy for precipitation amount in the high‐altitude catchment of the karst recharge system. The oxygen record shows millennial variability that is consistent with Greenland Interstadials GI25–23 and North Atlantic cold events C24–C22, indicating a strong Mediterranean–North Atlantic climate teleconnection. However, while no appreciable isotopic difference between the three interstadials is revealed by the Greenland record, the Sulmona section reveals a wetter climate during GI24 compared with GI23 and GI25. Comparison of our record with speleothem and pollen data from central and southern Italy suggests higher seasonality of the precipitation (wet winter–dry summer) for GI24, which matches a precession minimum. The wettest period recorded at Sulmona is also coincident with the deposition of Sapropel S4 in the Tyrrhenian Sea, suggesting a teleconnection between a higher seasonality in the western Mediterranean and strengthening of the boreal monsoon system.
Last Glacial droughts and fire regimes in the central Mexican highlands
Authors: TORRES‐RODRÍGUEZ E. , LOZANO‐GARCÍA S. , ROY P. , ORTEGA B. , BERAMENDI‐OROSCO L. , CORREA‐METRIO A. , CABALLERO M.
Published: January 2015

Over the last glacial cycle, climate variations in the Neotropics were related to diverse forcing mechanisms whose understanding has been limited because of the scarcity of continuous long records. Here we use high‐resolution charcoal particle accumulation, inorganic carbon precipitation and magnetic susceptibility data from Lake Chalco, located in high‐altitude tropical central Mexico, to assess the fire regimes and drought periods between ∼85 and 10.8k cal a BP. Overall, drought intervals were characterized by high carbonate deposition and were contemporary with high spring insolation. Most of the high fire activity periods were coupled with droughts, whereas some of them seem to have responded to volcanic activity in the basin. Periods of more fire activity during the latest part of Marine Isotope Stage 3 were associated with a long interval of higher spring insolation. Increase in drought frequency during 47–27k cal a BP were possibly linked to a more active Laurentide Ice Sheet influencing the oceanic and atmospheric controls of the tropical climatic system. In fact, Chalco and Cariaco records show similar millennial‐scale trends, suggesting a role of the Intertropical Convergence Zone in modulating moisture availability in the region.
240 Hz OLED technology properties that can enable improved image quality
Authors: Hoffman David M. , Johnson Paul V. , Kim Joohwan S. , Vargas Andy D. , Banks Martin S.
Published: January 2015

Large screen Organic Light Emitting Diode (OLED) technology is finally emerging as a technology ready for consumer use. OLED has a number of areas in which it can in principle be better than Liquid Crystal Displays (LCDs); two ways in particular are that OLED technology can achieve black levels that are much darker than LCDs, and the OLED pixels can switch extremely rapidly. These differences can permit OLED displays to outperform LCD under a number of conventional scenarios, but it can also enable some dramatically improved stereoscopic 3D (s3D) displays, including full‐resolution temporal multiplexing with more than two views. In this paper, we review a set of experiments evaluating the strengths and weaknesses of OLED technology in general with a particular emphasis on understanding how the strengths of OLED technology can be leveraged to maximize the performance of an s3D display system.
Does intraoperative nerve monitoring reliably aid in staging of total thyroidectomies?
Authors: Fontenot Tatyana E. , Randolph Gregory W. , Setton Tedhar E. , Alsaleh Nuha , Kandil Emad
Published: January 2015

Objectives/Hypothesis

Demonstrate whether intraoperative nerve monitoring is an effective tool in staging bilateral thyroid and neck surgeries in cases of intraoperative injury to the recurrent laryngeal nerve on the side of initial dissection. We hypothesized that IONM provides reliable and appropriate feedback on the functional status of the RLN on side of initial dissection during total thyroidectomy and central neck surgery.

Study Design

Case series with planned data collection.

Methods

All patients receiving total thyroidectomies or central neck surgeries were reviewed. The outcomes of patients treated whose procedures were staged based on intraoperative nerve monitoring are described.

Results

Ten (4.9%) of 206 procedures were staged based on unfavorable signal change including six patients with thyroid cancers and four with compressive substernal goiters. The overall signal drop in the 10 patients with unfavorable signal change was 63%. Three patients had complete loss of signal. In the other seven patients, the signal dropped by a mean of 48%. In the eight patients with laryngoscopy‐proven vocal fold paresis, the signal dropped by a mean of 68%.

Conclusions

Intraoperative nerve monitoring results accurately indicated postoperative ipsilateral vocal cord dysfunction with high reliability. Intraoperative nerve monitoring is a reliable tool in staging thyroid surgery.

Level of Evidence

4. Laryngoscope, 125:2232–2235, 2015
Noninvasive depth‐resolved optical measurements of the tympanic membrane and middle ear for differentiating otitis media
Authors: Monroy Guillermo L. , Shelton Ryan L. , Nolan Ryan M. , Nguyen Cac T. , Novak Michael A. , Hill Malcolm C. , McCormick Daniel T. , Boppart Stephen A.
Published: January 2015

Objective/Hypothesis

In this study, optical coherence tomography (OCT) is used to noninvasively and quantitatively determine tympanic membrane (TM) thickness and the presence and thickness of any middle‐ear biofilm located behind the TM. These new metrics offer the potential to differentiate normal, acute, and chronic otitis media (OM) infections in pediatric subjects.

Study Design

Case series with comparison group.

Methods

The TM thickness of 34 pediatric subjects was acquired using a custom‐built, handheld OCT system following a traditional otoscopic ear exam.

Results

Overall thickness (TM and any associated biofilm) was shown to be statistically different for normal, acute, and chronic infection groups (normal‐acute and normal‐chronic: P value < 0.001; acute‐chronic: P value = 0.0016). Almost all observed scans from the chronic group had an accompanying biofilm structure. When the thickness of the TM and biofilm were considered separately in chronic OM, the chronic TM thickness correlated with the normal group (P value = 0.68) yet was still distinct from the acute OM group (P value < 0.001), indicating that the TM in chronic OM returns to relatively normal thickness levels.

Conclusion

Identifying these physical changes in vivo provides new metrics for noninvasively and quantitatively differentiating normal, acute, and chronic OM. This new diagnostic information has the potential to assist physicians to more effectively and efficiently screen, manage, and refer patients based on quantitative data.

Level of Evidence

4. Laryngoscope, 125:E276–E282, 2015
Catch the Peak
Authors: Frede Maik , Engelbrecht Martin
Published: January 2015

Nowadays, many laser material applications are driven by pulsed laser systems providing a broad range of laser parameters. Laser processing like marking, drilling, cutting or advanced surface structuring are using lasers with less than a micro‐ down to femtosecond pulse durations and pulse energies from micro‐ to millijoule. Process speed is driven by the laser's repetition rate covering the range from single pulse up to megahertz rates. The variety of laser parameters motivates for flexible laser system architectures in which optical amplifiers play a core role in scaling the lasers pulse energy. This article will give an overview of optical amplifier technologies and concepts for a flexible configuration of laser parameters.
Tuning for Resonances
Authors: Gomez Luis F. , Sperling Jaroslaw
Published: January 2015

Due to a very distinct spectrum of resonant frequencies, the characterization of optical microcavities calls for widely tunable sources of continuous wave laser light, offering suitably narrow linewidths and single‐mode operation over the entire tuning range. This is why external cavity diode lasers, which allow for mode‐hop free wavelength tuning, often over more than a hundred nanometers, have matured to a fundamental tool of the optical microresonator research apparatus.
Resting‐state frontostriatal functional connectivity in Parkinson's disease–related apathy
Authors: Baggio Hugo Cesar , Segura Bàrbara , Garrido‐Millan Jose Luis , Marti Maria‐José , Compta Yaroslau , Valldeoriola Francesc , Tolosa Eduardo , Junque Carme
Published: January 2015

One of the most common neuropsychiatric symptoms in Parkinson's disease (PD) is apathy, affecting between 23% and 70% of patients and thought to be related to frontostriatal dopamine deficits. In the current study, we assessed functional resting‐state frontostriatal connectivity and structural changes associated with the presence of apathy in a large sample of PD subjects and healthy controls, while controlling for the presence of comorbid depression and cognitive decline. Thirty‐one healthy controls (HC) and 62 age‐, sex‐, and education‐matched PD patients underwent resting‐state functional magnetic resonance imaging (MRI). Apathy symptoms were evaluated with the Apathy Scale (AS). The 11 Beck Depression Inventory‐II items that measure dysphoric mood symptoms as well as relevant neuropsychological scores were used as nuisance factors in connectivity analyses. Voxel‐wise analyses of functional connectivity between frontal lobes (limbic, executive, rostral motor, and caudal motor regions), striata (limbic, executive, sensorimotor regions), and thalami were performed. Subcortical volumetry/shape analysis and fronto‐subcortical voxel‐based morphometry were performed to assess associated structural changes. Twenty‐five PD patients were classified as apathetic (AS > 13). Apathetic PD patients showed functional connectivity reductions compared with HC and with non‐apathetic patients, mainly in left‐sided circuits, and predominantly involving limbic striatal and frontal territories. Similarly, severity of apathy negatively correlated with connectivity in these circuits. No significant effects were found in structural analyses. Our results indicate that the presence of apathy in PD is associated with functional connectivity reductions in frontostriatal circuits, predominating in the left hemisphere and mainly involving its limbic components. © 2015 International Parkinson and Movement Disorder Society
Accelerated five‐dimensional echo planar J‐resolved spectroscopic imaging: Implementation and pilot validation in human brain
Authors: Wilson Neil E. , Iqbal Zohaib , Burns Brian L. , Keller Margaret , Thomas M. Albert
Published: January 2015

Purpose

To implement an accelerated five‐dimensional (5D) echo‐planar J‐resolved spectroscopic imaging sequence combining 3 spatial and 2 spectral encoding dimensions and to apply the sequence in human brain.

Methods

An echo planar readout was used to acquire a single spatial and a single spectral dimension during one readout. Nonuniform sampling was applied to the two phase‐encoded spatial directions and the indirect spectral dimension. Nonlinear reconstruction was used to minimize the
‐norm or the total variation and included a spectral mask to enhance sparsity. Retrospective reconstructions at multiple undersamplings were performed in phantom. Ten healthy volunteers were scanned with 8× undersampling and compared to a fully sampled single slice scan.

Results

Retrospective reconstruction of fully sampled phantom data showed excellent quality at 4×, 8×, 12×, and 16× undersampling using either reconstruction method. Reconstruction of prospectively acquired in vivo scans with 8× undersampling showed excellent quality in the occipito‐parietal lobes and good quality in the frontal lobe, consistent with the fully sampled single slice scan.

Conclusion

By utilizing nonuniform sampling with nonlinear reconstruction, 2D J‐resolved spectra can be acquired over a 3D spatial volume with a total scan time of 20 min, which is reasonable for in vivo studies. Magn Reson Med 75:42–51, 2016. © 2015 Wiley Periodicals, Inc.
Normative biometrics for fetal ocular growth using volumetric MRI reconstruction
Authors: Velasco‐Annis Clemente , Gholipour Ali , Afacan Onur , Prabhu Sanjay P. , Estroff Judy A. , Warfield Simon K.
Published: January 2015

Objective

To determine normative ranges for fetal ocular biometrics between 19 and 38 weeks gestational age (GA) using volumetric MRI reconstruction.

Method

The 3D images of 114 healthy fetuses between 19 and 38 weeks GA were created using super‐resolution volume reconstructions from MRI slice acquisitions. These 3D images were semi‐automatically segmented to measure fetal orbit volume, binocular distance (BOD), interocular distance (IOD), and ocular diameter (OD).

Results

All biometry correlated with GA (Volume, Pearson's correlation coefficient (CC) = 0.9680; BOD, CC = 0.9552; OD, CC = 0.9445; and IOD, CC = 0.8429), and growth curves were plotted against linear and quadratic growth models. Regression analysis showed quadratic models to best fit BOD, IOD, and OD and a linear model to best fit volume.

Conclusion

Orbital volume had the greatest correlation with GA, although BOD and OD also showed strong correlation. The normative data found in this study may be helpful for the detection of congenital fetal anomalies with more consistent measurements than are currently available. © 2015 John Wiley & Sons, Ltd.
Residence time distributions in a co‐kneader: A chemical engineering approach
Authors: Monchatre Benjamin , Raveyre Claude , Carrot Christian
Published: January 2015

In this article, we have studied the residence time distributions (RTD) in a modular co‐kneader. Several papers have already addressed the co‐kneader modeling and operating mode but there is still a lack of experimental data on RTD. To investigate the RTD, we have used a colored tracer dispersed in polypropylene (PP) that was injected in the flow during the compounding of neat PP. The effect of operating parameters such as temperature, feed rate, and screw configuration was investigated, focusing on the influence of mixing and conveying elements in a zone where the polymer is molten. As can be expected, results on various screw configurations show that increasing the number of kneading elements makes the RTD longer. More interestingly, for a defined set of elements, their position does not change the experimental RTD. A chemical engineering approach was used to model the RTD, with an equation derived from a cascade of continuous stirred tank reactors. The model allows to retrieve an elementary RTD for each section of a defined type of elements and to propose a law for their combination in good agreement with experiments. POLYM. ENG. SCI., 55:1237–1245, 2015. © 2015 Society of Plastics Engineers
Quantifying interface states and bulk defects in high‐efficiency solution‐processed small‐molecule solar cells by impedance and capacitance characteristics
Authors: Brus Viktor V. , Kyaw Aung Ko Ko , Maryanchuk Pavlo D. , Zhang Jie
Published: January 2015

The AC properties of high‐efficiency (η = 8.01% under standard 100 mW/cm2 AM1.5 illumination) small‐molecule bulk heterojunction (SM BHJ) solar cells (p‐DTS(FBTTh2)2/PC70BM) at different DC biases and frequencies of small amplitude (±10 mV) AC signal in the dark at room temperature were investigated in details. We showed the presence of interface states at the heterojunction interface and determined their parameters from the analysis of spectral distributions of real and imaginary components of the measured impedance. The dielectric constant of BHJ εBHJ = 2.9 was determined from the geometrical capacitance of totally depleted BHJ layer. We explained quantitatively the effect of interface states and series resistance on the measured C‐V characteristics of the SM BHJ solar cells at both low and high frequencies. The quantitative value of the density of defect states in the bulk N = 1.05 × 1016 cm−3 was determined from the high frequency C‐V characteristic corrected by the effect of the series resistance. Copyright © 2015 John Wiley & Sons, Ltd.
Workflows for automated downstream data analysis and visualization in large‐scale computational mass spectrometry
Authors: Aiche Stephan , Sachsenberg Timo , Kenar Erhan , Walzer Mathias , Wiswedel Bernd , Kristl Theresa , Boyles Matthew , Duschl Albert , Huber Christian G. , Berthold Michael R. , Reinert Knut , Kohlbacher Oliver
Published: January 2015

MS‐based proteomics and metabolomics are rapidly evolving research fields driven by the development of novel instruments, experimental approaches, and analysis methods. Monolithic analysis tools perform well on single tasks but lack the flexibility to cope with the constantly changing requirements and experimental setups. Workflow systems, which combine small processing tools into complex analysis pipelines, allow custom‐tailored and flexible data‐processing workflows that can be published or shared with collaborators. In this article, we present the integration of established tools for computational MS from the open‐source software framework OpenMS into the workflow engine Konstanz Information Miner (KNIME) for the analysis of large datasets and production of high‐quality visualizations. We provide example workflows to demonstrate combined data processing and visualization for three diverse tasks in computational MS: isobaric mass tag based quantitation in complex experimental setups, label‐free quantitation and identification of metabolites, and quality control for proteomics experiments.
Changes in protein structure monitored by use of gas‐phase hydrogen/deuterium exchange
Authors: Beeston Helen S. , Ault James R. , Pringle Steven D. , Brown Jeffery M. , Ashcroft Alison E.
Published: January 2015

The study of protein conformation by solution‐phase hydrogen/deuterium exchange (HDX) coupled to MS is well documented. This involves monitoring the exchange of backbone amide protons with deuterium and provides details concerning the protein's tertiary structure. However, undesired back‐exchange during post‐HDX analyses can be difficult to control. Here, gas‐phase HDX‐MS, during which labile hydrogens on amino acid side chains are exchanged in sub‐millisecond time scales, has been employed to probe changes within protein structures. Addition of the solvent 2,2,2‐trifluoroethanol to a protein in solution can affect the structure of the protein, resulting in an increase in secondary and/or tertiary structure which is detected using circular dichroism. Using a Synapt G2‐S ESI‐mass spectrometer modified to allow deuterated ammonia into the transfer ion guide (situated between the ion mobility cell and the TOF analyser), gas‐phase HDX‐MS is shown to reflect minor structural changes experienced by the proteins β‐lactoglobulin and ubiquitin, as observed by the reduction in the level of deuterium incorporation. Additionally, the use of gas‐phase HDX‐MS to distinguish between co‐populated proteins conformers within a solution is demonstrated with the disordered protein calmodulin; the gas‐phase HDX‐MS results correspond directly with complementary data obtained by use of ion mobility spectrometry‐MS.
Recent advances in the diagnosis and management of glaucoma
Authors: Azarbod Parham , Crawley Laura , Ahmed Faisal , Cordeiro M Francesca , Bloom Philip
Published: January 2015

Reducing intraocular pressure remains the only treatment option in glaucoma, however, prompt evaluation and management can prevent blindness and a lifetime of disability. Our Drug Review outlines the key points and recent advances in diagnosis and management.
Management of peripheral arterial disease in primary care
Authors: Bignell Mark , Shearman Cliff
Published: January 2015

Early recognition of peripheral arterial disease, medical optimisation and appropriate referral to secondary care can all reduce the risk of cardiovascular events.
Investigations of dynamic performance in AlGaN/GaN HFETs with field plates by stressed C–V and dynamic on‐resistance measurements
Authors: Liao Wen‐Chia , Chyi Jen‐Inn , Hsin Yue‐Ming
Published: January 2015

Stressed C–V measurement was used to extract the trap profiles in AlGaN/GaN HFETs with field plates enduring high‐voltage off‐state stress. The C–V measurement results also correlated with the degradation in dynamic on‐resistance (RDS,on) after transistors were stressed with similar stress conditions. Based on the correlation between the trap profiles and dynamic RDS,on degradation, the location with high electric field that determines the major degradation is determined. Finally, a new source field plate is proposed and demonstrated to improve the dynamic performance degradation.
Complementary and bipolar regimes of resistive switching in TiN/HfO2/TiN stacks grown by atomic‐layer deposition
Authors: Egorov K. V. , Kirtaev R. V. , Lebedinskii Yu. Yu. , Markeev A. M. , Matveyev Yu. A. , Orlov O. M. , Zablotskiy A. V. , Zenkevich A. V.
Published: January 2015

Atomic‐layer deposition (ALD) technique in combination with in vacuo X‐ray photoelectron spectroscopy (XPS) analysis has been successfully employed to obtain fully ALD‐grown planar TiN/HfO2/TiN metal–insulator–metal structures for resistive random access memory (ReRAM) memory elements. In vacuo XPS analysis of ALD‐grown TiN/HfO2/TiN stacks reveals the presence of the ultrathin oxidized layers consisting of TiON (∼0.5 nm) and TiO2 (∼0.6 nm) at the bottom TiN/HfO2 interface (i); the nonoxidized TiN at the top HfO2/TiN interface (ii); the oxygen deficiency in the HfO2 layer does not exceed the XPS detection limit (iii). Electroformed ALD TiN/HfO2/TiN stacks reveal both conventional bipolar and complementary types of resistive switching. In the complementary resistive switching regime, each programming sequence is terminated by a reset operation, leaving the TiN/HfO2/TiN stack in a high‐resistance state. The observed feature can avoid detrimental leaky paths during successive reading operation, which is useful in the passive ReRAM arrays without a selector element. The bipolar regime of resistive switching is found to reveal the gradual character of the SET and RESET switching processes. Long‐term potentiation and depression tests performed on ALD‐grown TiN/HfO2/TiN stacks indicate that they can be used as electronic synapse devices for the implementation of emerging neuromorphic computation systems.
Chemical understanding and utility of H3PO4 etching of group‐III‐ nitrides
Authors: Reiner Maria , Reiss Marcus , Brünig Thorge , Knuuttila Lauri , Pietschnig Rudolf , Ostermaier Clemens
Published: January 2015

The etch mechanism of group‐III‐nitrides in hot H3PO4 has been studied and compared to KOH. The etched surfaces were investigated by AFM, SEM, TEM, EDX and the etch solutions by NMR. AlGaN is shown to be selectively etched by low temperature H3PO4 or molten KF · 2H2O. The material dependency causes much flatter etch pit angles for AlGaN over GaN as well as H3PO4 over molten KOH. 27Al‐NMR investigations prove a fast ligand exchange as well as homogenous ligands. 31P‐NMR confirms that the dissolved metal is present as AlH2PO42+ and no hydration takes place nor does water play a role in the chemical reaction, opposed to KOH etching. Hence we propose a dissolution limited etch mechanism which can explain difference etch pit angles and material dependencies, as they are the result of material dependent dissolution, assuming that the vertical etch rate is constant.
Self‐organized growth of catalyst‐free GaN nano‐ and micro‐rods on Si(111) substrates by MOCVD
Authors: Foltynski B. , Giesen C. , Heuken M.
Published: January 2015

Our study shows the impact of the process parameters: predose before AlN buffer deposition, SiNx deposition time, GaN growth temperature and silane injection time on growth and morphology of GaN nanowires (NWs) formed by a self‐organized mechanism on a silicon substrate. We determined a process parameter window for successful GaN NW growth and show how the variation of studied parameters changes the NW morphology and density. The optimization of these process parameters led to high‐density straight GaN NWs, aligned perpendicular to the substrate. The use of a preflow before AlN buffer deposition was found to be important for the successful NW formation, and most interestingly, led to a difference in structural morphology for ammonia and TMAl predose.
Model for carrier capture time through phonon emission in InGaN/GaN quantum wells
Authors: Vallone Marco , Bertazzi Francesco , Goano Michele , Ghione Giovanni
Published: January 2015

A self‐energy‐based model for the calculation of the electron capture time through phonon emission in presence of carrier population is applied to nitride‐based quantum wells (QWs). The role of plasma dynamical screening on the Frölich interaction is investigated, highlighting its central role in the dependence of capture time on carrier density. The proposed approach yields a closed‐form expression for capture time as a function of the carrier densities in QW and barrier states. Its application to simple two‐population rate equations allows to reproduce available experimental data with excellent agreement, offering an accurate yet practical alternative to the usual approximation of a constant capture time in modeling light‐emitting diodes and lasers.
Hydrothermal Synthesis of New Organically Templated Beryllium Phosphite and Phosphate with 3,4‐connected Networks
Authors: Zhao Xiao‐Meng , Li Jin‐Hua , Wang Guo‐Ming , Zhang Xiao
Published: January 2015

Two organically templated beryllium phosphite and phosphate, [H2tmpda][Be3(HPO3)4] (1) and [H2ampy][Be3(HPO4)4] (2) [tmpda = N,N,N′,N′‐tetramethyl‐1,3‐propanediamine, ampy = 3‐(aminomethyl)pyridine], were synthesized and structurally characterized. Compound 1 exhibits a (3,4)‐connected layered structure with eight‐ring windows, and it has a 44 grid topology by regarding the heptameric [Be3(HPO3)4] group as a 4‐connected node in the layer. Compound 2 possesses a different (3,4)‐connected three‐dimensional framework with multidirectional 8‐ring channels and zigzag 12‐ring channels. This 3D architecture shows a pcu topology when the heptameric [Be3(HPO4)4] groups are regarded as 6‐connected secondary building units. Crystal data: 1, monoclinic, P21/m, a = 8.0217(6) Å, b = 13.7969(5) Å, c = 8.6581(2) Å, β = 92.315(3)°, V = 957.45(8) Å3, Z = 2, R1 = 0.0761, wR2 = 0.1640; 2, monoclinic, P21/n, a = 7.5292(5) Å, b = 14.0999(8) Å, c = 16.5910(3) Å, β = 95.740(3)°, V = 1752.49(16) Å3, Z = 4, R1 = 0.0434, wR2 = 0.1017.
The Electrophilic Character of Bunsen's Cacodyl Disulfide, Me2As(S)‐S‐AsMe2, Towards Some Nucleophiles of Groups 15 and 16
Authors: Ioannou Panayiotis V. , Vachliotis Dimitris G.
Published: January 2015

The reactivity of Bunsen's cacodyl disulfide, Me2As(S)‐S‐AsMe2, towards nitrogen, phosphorus(III), oxygen and sulfur(II) nucleophiles was evaluated with the aim at identifying its electrophilic atom. The nitrogen nucleophiles either did not react or bind or split the disulfide. All phosphorus(III) nucleophiles desulfurized it. Water, methanol and phenol did not react but thiophenol reacted giving an equilibrated system. The anions MeO–, PhO– and PhS– split the disulfide. From the results obtained it seems that the arsenic and sulfur of the As = S group are the most likely electrophilic atoms depending on the nature of the nucleophile, the AsIII being much less reactive in the presence of As=S.
The stability–complexity relationship at age 40: a random matrix perspective
Authors: Allesina Stefano , Tang Si
Published: January 2015

Since the work of Robert May in 1972, the local asymptotic stability of large ecological systems has been a focus of theoretical ecology. Here we review May's work in the light of random matrix theory, the field of mathematics devoted to the study of large matrices whose coefficients are randomly sampled from distributions with given characteristics. We show how May's celebrated “stability criterion” can be derived using random matrix theory, and how extensions of the so‐called circular law for the limiting distribution of the eigenvalues of large random matrix can further our understanding of ecological systems. Our goal is to present the more technical material in an accessible way, and to provide pointers to the primary mathematical literature on this subject. We conclude by enumerating a number of challenges, whose solution is going to greatly improve our ability to predict the stability of large ecological networks.
Are Australasian Genetic Counselors Interested in Private Practice at the Primary Care Level of Health Service?
Authors: Sane Vrunda , Humphreys Linda , Peterson Madelyn
Published: January 2015

This study explored the perceived interest in development of private genetic counseling services in collaboration with primary care physicians in the Australasian setting by online survey of members of the Australasian Society of Genetic Counselors. Four hypothetical private practice models of professional collaboration between genetic counselors and primary care physicians or clinical geneticists were proposed to gauge interest and enthusiasm of ASGC members for this type of professional development. Perceived barriers and facilitators were also evaluated. 78 completed responses were included for analysis. The majority of participants (84.6 %) showed a positive degree of interest and enthusiasm towards potential for clinical work in private practice. All proposed practice models yielded a positive degree of interest from participants. Model 4 (the only model of collaboration with a clinical geneticist rather than primary care physician) was the clearly preferred option (mean = 4.26/5), followed by Model 2 (collaboration with a single primary care practice) (mean = 4.09/5), Model 3 (collaboration with multiple primary care clinics, multidisciplinary clinic or specialty clinic) (mean = 3.77/5) and finally, Model 1 (mean = 3.61/5), which was the most independent model of practice. When participants ranked the options in the order of preference, Model 4 remained the most popular first preference (44.6 %), followed by model 2 (21.6 %), model 3 (18.9 %) and model 1 was again least popular (10.8 %). There was no significant statistical correlation between demographic characteristics (age bracket, years of work experience, current level of work autonomy) and participants’ preference for private practice models. Support from clinical genetics colleagues and the professional society was highly rated as a facilitator and, conversely, lack of such support as a significant barrier.
Rural-to-Urban Migration and Changes in Health Among Young Adults in Thailand
Authors: Nauman Elizabeth , VanLandingham Mark , Anglewicz Philip , Patthavanit Umaporn , Punpuing Sureeporn
Published: January 2015

We investigate the impacts of rural-to-urban migration on the health of young adult migrants. A key methodological challenge involves the potentially confounding effects of selection on the relationship between migration and health. Our study addresses this challenge in two ways. To control for potential effects of prior health status on post-migration health outcomes, we employ a longitudinal approach. To control for static unobserved characteristics that can affect migration propensity as well as health outcomes, we use fixed-effects analyses. Data were collected in 2005 and 2007 for a cohort of young adults in rural Kanchanaburi province, western Thailand. The migrant sample includes individuals who subsequently moved to urban destinations where they were reinterviewed in 2007. Return migrants were interviewed in rural Kanchanaburi in both years but moved to an urban area and returned in the meantime. A rural comparison group comprises respondents who remained in the origin villages. An urban comparison sample includes longer-term residents of the urban destination communities. Physical and mental health measures are based on the SF-36 health survey. Findings support the “healthy migrant hypothesis.” Migrants are physically healthier than their nonmigrant counterparts both before and after moving to the city. We did not find an effect of migration on physical health. Rural-to-urban migrants who stayed at destination experienced a significant improvement in mental health status. Fixed-effects analyses indicate that rural-to-urban migration positively affects mental health. Return migrants do not fare as well as migrants who stayed at destination on both physical and mental health status—evidence of selective return migration.
Improving general practitioners’ referral details of antidepressant use for patients referred for depression to primary mental health care: re-audit
Authors: Towobola A. , Cunningham E. , Cotter P.
Published: January 2015

Background

This audit cycle looked at details of antidepressants given in general practitioners’ (GPs) referral letters to Primary Mental Health Care (PMHC). With adequate information when patients are referred, time spent in clarifying details could be put into better use by clinicians and prompt effective treatment would help to reduce the direct and indirect costs of depression.

Objective

To evaluate how effective our intervention was 7 months after a previous audit and identify areas that need improvement.

Method

Audit of 33 referral letters of patients referred for depression from GPs to a PMHC service in Northern Ireland, followed by the intervention (feedback and pro forma) and re-audit after 7 months.

Results

The April audit showed 100% documentation of current antidepressant treatment and dose, but showed poor documentation of previous antidepressant use (33%), dose or duration (15%) and the reason for stopping the treatment (3%). Following intervention, the re-audit showed 25% and 24% rise in documenting previous antidepressant used and maximum dose reached, respectively, and 20% rise in documenting the reason for stopping.

Conclusions

Our interventions made modest improvement in providing relevant data in referral letters. This study adds to the existing evidence that relying mainly on feedback as a method of implementing change is ineffective. Lack of enthusiasm for using the newly introduced pro forma suggests that mental health services should obtain more effective ways of engaging GPs in service development. Using a systematic approach, which includes identifying local barriers to change and providing a supportive environment are important before the next re-audit.
Experimental study of bedforms obtained with floating particles in a pipe flow
Authors: Edelin D. , Josset C. , Castelain C. , Fayolle F.
Published: January 2015

We investigate experimentally the formation of bedforms caused by the sustained flow of water and solid particles in a circular pipe ($\varnothing =30~\text{mm}$). The special feature of the tests carried out was the use of floating particles ($d=756~{\rm\mu}\text{m}$, ${\it\rho}_{s}=907~\text{kg}~\text{m}^{-3}$) whereas bedforms are usually studied with sedimental materials. A closed loop was used, so that the solid flux could be maintained for an infinite time. The finite size of the tube led to the saturation of the growth of the vortex ripples produced. For the set of parameters studied, the threshold of motion was obtained within a range of laminar to low turbulent flow. The saturated state was studied to characterise it for different flow rates and solid loads. The frequency, wavelength and propagating velocity of ripples were determined using different methodologies based on image analysis and pressure analysis. The frequency and propagating velocity show a clear linear dependence on the initial Shields number, while the wavelength seems to be constant in our experiments.
On the stability of the tangential discontinuity interface in dusty plasma
Authors: Ershkovich A. I. , Israelevich P. L.
Published: January 2015

Stability of the plane tangential discontinuity (TD) interface in a multi-component dusty plasma (ions, electrons, neutral particles and charged dust) is considered in hydrodynamical approximation. The criterion of stability does not depend on the presence of dust only on one side of the discontinuity but is changed if the dust penetrates through the discontinuity. Therefore, if the instability criterion is marginal, even weak penetration of the dust through the interface may induce Kelvin–Helmholtz instability. This conclusion also refers to cylindrical TD in the presence of dust, so that generation of helical waves in astrophysical jets, type I comet tails, etc. due to the shear driven Kelvin–Helmholtz instability may be hampered in dusty objects of such a geometry.
Richard Maitland Laws
Authors: Block William
Published: January 2015

Richard Maitland Laws (Fig. 1) died on 7 October 2014. Usually known as known as Dick Laws, his career spanned the world. From his Northumbrian upbringing his career as a zoologist took him via Cambridge University to the Southern Ocean, the cold of Antarctica, the heat of Africa, the Directorship of the British Antarctic Survey and the Mastership of a Cambridge College.
NO REVERSAL OF FORTUNE IN THE LONG RUN: GEOGRAPHY AND SPATIAL PERSISTENCE OF PROSPERITY IN COLOMBIA, 1500-2005
Authors: Meisel Adolfo
Published: January 2015

This paper examines the non-reversal of fortune thesis proposed by Acemoglu et al. (2002) in the light of the Colombian experience over the last 500 years. Using a total of fourteen national population censuses and the record of tributary Indians in 1559, it is found that the population density of Colombian regions presented a high degree of persistence through time. Thus, the evidence indicates that those places that were prosperous circa 1500 remain so today, and vice versa. These results indicate that the long-run influences of geography on regional economic disparities within a country are not negligible.
CAMBIOS EN LA ESTRUCTURA DE LAS RENTAS PÚBLICAS DE YUCATÁN, 1850-1902
Authors: Campos García Melchor
Published: January 2015

El artículo analiza los cambios en la estructura tributaria de Yucatán, México, durante la transición del régimen colonial a la fiscalidad liberal, de 1850 a 1902. Caracteriza sus etapas en función de la composición y el protagonismo alternativo de los impuestos directos y los impuestos indirectos en las rentas públicas. Durante los profundos cambios en la estructura económica, la tributación indirecta al consumo y los impuestos directos sobre los sectores secundario y terciario protegieron el crecimiento del sector productivo del henequén (1869-1882). Finalmente, el impuesto sobre el henequén no sustituyó a los ingresos indirectos. La modernización fiscal (1896-1902) equilibró la tributación directa de producto con los aplicados a sectores más urbanos, el secundario y las ventas del sector mercantil.