bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding Achilles’ Heel: Information Dissemination, Readability, and Marketing in Urban School Choice
Authors: Delale-O’Connor Lori
Published: March 2018

Scholars have long acknowledged that the information parents have about schools is the “Achilles’ heel” of school choice. Although much has been written about school choice, far less is known about the information disseminated to help families make choices. I construct a case study of the dissemination and accessibility of choice information in the Chicago Public Schools. I find that both the readability and content of the information disseminated limit its usefulness. In addition, a lack of centralized resources leads to both limited and disparate access. I conclude with modifications for improving information dissemination and accessibility.
Structured Observation Instruments Assessing Instructional Practices With Gifted and Talented Students: A Review of the Literature
Authors: Farah Yara N. , Chandler Kimberley L.
Published: March 2018

Teaching and learning are part of a complex interaction between teachers and students. Educational leaders cannot improve the teaching and learning process without quality measurement of effective teaching. One way to capture this complex interaction is by using structured observations. However, the extant literature on classroom observation instruments in the field of gifted education is limited. For that reason, a systematic search was undertaken to identify the observation instruments for assessing instructional practices used with gifted and talented students. In this article, eight observation instruments were identified: (a) Rating Scale of Significant Behaviors in Teachers of the Gifted, (b) Kulieke’s adaptation of the Rating Scale of Significant Behaviors in Teachers of the Gifted, (c) Teaching Observation Form (TOF; also known as Purdue Observation Form), (d) Classroom Practices Record (CPR), (e) Classroom Practices Record–Form VA (CPR-Form VA), (f) Classroom Instructional Practices Scale (CIPS), (g) Classroom Observation Scales–Revised (COS-R), and (h) Differentiated Classroom Observation Scale (DCOS). The instruments are described in terms of developmental process, purpose, and any reliability and validity evidence reported. This systematic search has shown the need for a new observation instrument that is comprehensive and closely tied to professional standards.
A study of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) biofilms’ thermal and biodegradable properties reinforced with halloysite nanotubes
Authors: Hasan SM Kamrul , Zainuddin S , Tanthongsack J , Hosur MV , Allen L
Published: March 2018

The aim of this study is to investigate and optimize the performance of a promising biopolymer, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) which can potentially replace non-biodegradable synthetic polymers derived from toxic petroleum products. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) biofilms were prepared using solvent casting method, and its thermal properties were determined using thermogravimetric and differential scanning calorimetry techniques. Also, the durability and biodegradability of these films were studied by keeping the samples in water and Alabama soil conditions for various lengths of time. Our results showed that the thermal and moisture resistance of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) biopolymer can be enhanced significantly with the addition of low halloysite nanotubes concentrations. Also, the biodegradation process of the poly (3-hydroxybutyrate-co-3-hydroxyvalerate) films was faster with the addition of halloysite nanotubes attributed to the accelerated microbial microorganism reaction in the soil. This study led to cognize that the PHBV biopolymers added with halloysite nanotubes can be successfully used for various biomedical, industrial and structural applications, and then decompose at a desired faster rate afterward.
Impact response in polymer composites from embedded optical fibers
Authors: Batte Lorianne K , Sullivan Rani W , Ranatunga Vipul , Brown Kevin
Published: March 2018

This study investigates the feasibility of using embedded optical fibers in polymer matrix composite laminates to characterize delaminations caused by low-velocity impacts with energies between 30 J and 50 J. Impact damage can occur in composite structures during manufacture, in-service, storage and routine maintenance. Because of their small size and light weight, optical fibers can be embedded in composite structures during the manufacture of composite parts, allowing the structure to be monitored for impact-induced delaminations without being removed from service. In this study, optical fibers are embedded in a grid configuration at four selected locations (one-third from impact surface, midplane, two-thirds from impact surface, and farthest ply from impact) in thick autoclave-cured graphite/epoxy laminates. Low-velocity impact testing is performed at four energy levels. Manufacturing procedures for embedding the optical fibers within the composite laminates are investigated. The strain distribution from the optical fibers is correlated with ultrasonic C-scans of the laminates in which they are embedded. X-ray computed tomography scan images are also compared to those from ultrasonic C-scans. Results indicate that embedded optical fibers can provide post-impact strain responses and delamination area from each embedded site within the impacted laminates.
Toward an Extended View of Evidence-Based Psychotherapy: Diversity and Societal Factors
Authors: Kousteni Ioanna D.
Published: March 2018

Scientifically, professionally, and ethically, evidence-based psychotherapy seems to be a well-balanced movement. Nonetheless, it has not yet succeeded in promoting the best treatment for every client, especially regarding diversity issues and societal stress factors that influence clients from minority groups. Evidence-based psychotherapy is mainly based on nosological systems of mental illness and the biomedical model rather than on social structuring of mental health problems. It combines many important parts of the picture but overlooks all the societal or contextual factors that influence mental health in every group of people, especially in groups of discriminated people. It is argued that this perspective promotes an individualistic view of mental health. There is a need for a different framework of evidence-based therapy that should include societal and contextual factors that influence the client and the therapy process. An extended view of evidence-based psychotherapy is proposed, which adds a “fourth dimension,” the “context of therapy,” to the definition of evidence-based psychotherapy along with the reorientation of research to more user-led and diversity-adapted practices. This article outlines a comprehensive framework of evidence-based psychotherapy that can work as a general guidance for researchers, health stakeholders, therapists, and training programs in psychotherapy.
Assessment in the Private Studio Setting: Supporting Student Learning, Providing Effective Instruction, and Building Faculty-Student Interaction
Authors: Laubenthal Jennifer
Published: March 2018

A significant amount of literature exists about how to design and implement an effective assessment process for students in a music program, specifically in the classroom setting. This article suggests a framework for incorporating individualized assessment in the private-lesson setting based on effective classroom assessment practices. Many in-service music teachers also teach privately. Applying their knowledge of classroom-based assessments and effective teaching strategies to the private-lesson setting can support student learning, provide effective instruction, and build faculty and student interaction. The private teacher plays a significant role in the education of music students. All music instructors—applied and classroom—should prioritize high-quality instruction, provide formative feedback to students, demonstrate teacher effectiveness to their employer (students, parents, or music educators), and use self-reflection to improve their instruction.
The Ethical Stakes of Collaborative Community-Based Social Science Research
Authors: Glass Ronald David , Morton Jennifer M. , King Joyce E. , Krueger-Henney Patricia , Moses Michele S. , Sabati Sheeva , Richardson Troy
Published: March 2018

This multivocal essay engages complex ethical issues raised in collaborative community-based research (CCBR). It critiques the fraught history and limiting conditions of current ethics codes and review processes, and engages persistent troubling questions about the ethicality of research practices and universities themselves. It cautions against positioning CCBR as a corrective that fully escapes these issues. The authors draw from a range of philosophic, African-centric, feminist, decolonial, Indigenous, and other critical theories to unsettle research ethics. Contributors point toward research ethics as a praxis of engagement with aggrieved communities in healing from and redressing historical trauma.
Estimating the Proportion of a Categorical Variable With Probit Regression
Authors: Martínez Sergio , Rueda Maria , Arcos Antonio , Martínez Helena
Published: March 2018

This article discusses the estimation of a population proportion, using the auxiliary information available, which is incorporated into the estimation procedure by a probit model fit. Three probit regression estimators are considered, using model-based and model-assisted approaches. The theoretical properties of the proposed estimators are derived and discussed. Monte Carlo experiments were carried out for simulated data and for real data taken from a database of confirmed dengue cases in Mexico. The probit estimates give valuable results in comparison to alternative estimators. Finally, the proposed methodology is applied to data obtained from an immigration survey.
The impact of workplace bullying in the Zimbabwean nursing environment: is social support a beneficial resource in the bullying–well-being relationship?
Authors: Finchilescu Gillian , Bernstein Colleen , Chihambakwe Davidzo
Published: March 2018

Bullying is an environmental workplace stressor that has severe implications for the bullied individual and the organisation. Nurses within Southern African hospitals face unique challenges, which can foster an environment within which bullying flourishes. In particular within public hospitals, there are shortages of doctors, equipment, and basic resources, and hospitals are grossly understaffed. This study investigated the effect of workplace bullying on nurses’ sense of well-being, their job satisfaction, and propensity to leave. The effectiveness of social support as a moderator of the impact of bullying was considered. A self-report questionnaire was completed by 102 nurses from a public hospital in Zimbabwe. Moderated multiple regression analyses were conducted on each of the outcomes of bullying. Workplace bullying was found to have a significant impact on the outcomes measured. Higher levels of bullying were associated with lowered job satisfaction and greater propensity to leave. Social support within the sample under study did not influence these outcomes, but did influence mental well-being as a moderator. At low and medium levels of experienced bullying, high levels of support promoted higher well-being than low and medium support. But this was not the case when there was a high level of bullying, where there was no difference in mental well-being as a function of the level of social support.
Psychopathic Traits and Recurring Victimization: An Examination Using a Community and Clinical Sample
Authors: Daigle Leah E. , Teasdale Brent
Published: March 2018

Few studies have identified specific characteristics of recurrent victims that distinguish them from single victims. One such characteristic that may do so is possessing psychopathic traits, given that persons with psychopathic traits are generally risk-seeking, callous, short-tempered, and lack behavioral controls. To examine this possibility, we use data from both the National Longitudinal Study of Adolescent to Adult Health (Add Health) and the MacArthur Violence Risk Assessment Study (MacRisk). We find that in both samples, psychopathic traits are able to distinguish between nonvictims and recurring victims as well as single-wave victims and recurring victims. This finding holds great promise for identifying who may be at risk of experiencing recurring victimization, ways to reduce victimization risk, as well as potential additional avenues for research in this area.
Brief Textual Indicators of Political Orientation
Authors: Okdie Bradley M. , Rempala Daniel M.
Published: March 2018

Language reflects one’s thoughts, feelings, and worldview. Technology has led to a proliferation of brief communications. Is this brief text meaningful? We examine whether text from brief political and nonpolitical communications reflect political ideology. Student responses to their ideological foundations (Study 1), brief snippets of unanimous Supreme Court verdicts (Study 2), and celebrity tweets (Study 3) were textually analyzed to examine whether they contained perceived threat and resistance to change content and whether this predicted the authors’ political affiliation. Across three studies, words related to resistance to change, but not perceived threat, were related to political ideology such that conservatives were more likely to include resistance-to-change-related words in their responses compared with liberals. These results suggest that brief text, even when not overtly political, reflects one’s political ideology. The increase in brief text production via new technology and its ability to predict political ideology make these findings particularly meaningful.
The heuristic value of the social: The effect of social quality and trust on welfare and tax attitudes
Authors: Im Dong-Kyun
Published: March 2018

In the last decades, enhancing social trust and improving social quality have been often considered as the antidote to the problems produced by the neoliberal makeover of the social life. However, it remains unclear whether higher social quality and trust actually produce more pro-social attitudes among people. Based on a statistical analysis of a cross-national survey administered in five countries, this article shows that social quality and social trust, as empirical indicators of the social, do not always generate pro-social attitudes. It demonstrates that perceived social quality and trust on social institutions can generate both conservative and liberal attitudes toward social welfare and taxation. In order to explain the varying effects of social quality and trust, we propose a heuristic model of political cognition and motivation, which illustrates how the political variety of the social is possible. Our model highlights the contextual contingencies of the political meaning of the social.
Microstructural and metabolic changes in the longitudinal progression of white matter hyperintensities
Authors: Jiaerken Yeerfan , Luo Xiao , Yu Xinfeng , Huang Peiyu , Xu Xiaojun , Zhang Minming ,   the Alzheimer's Disease Neuroimaging Initiative (ADNI)
Published: March 2018

Our purpose is to evaluate the microstructural and metabolism property in the white matter that later become white matter hyperintensity (WMH), and of WMH that later disappeared. Forty subjects with two-year follow-up were included. Each subject had 3DT1, T2FLAIR, DTI and FDG-PET scans. White matter was classified into: constant WMH, growing WMH, shrinking WMH and normal appearing white matter (NAWM). The average DTI (FA and MD) and FDG-PET (standardized FDG-PET rSUV) of each of the above-mentioned region were extracted and compared. At baseline, the growing WMH had lower FA and FDG-PET rSUV than NAWM, but had higher FA than the constant WMH. Longitudinally, in NAWM, there was a more rapid decline in metabolism compared to WMH areas, while in the growing WMH, a progression in diffusion was found. Finally, we discovered that the shrinking WMH had a similar microstructural and metabolism property and progression to the constant WMH. Our results suggest there are dynamic changes in microstructural and metabolism in WMH. The metabolic change was mainly found in NAWM, while the microstructural change was mainly found in WMH region. Besides, the reduced volume in WMH, to a larger extent, is irrelevant to the microstructural or metabolism recovery.
Longitudinal in vivo intrinsic optical imaging of cortical blood perfusion and tissue damage in focal photothrombosis stroke model
Authors: Yang Shanshan , Liu Kezhou , Ding Huijie , Gao Huan , Zheng Xiaoxiang , Ding Zhihua , Xu Kedi , Li Peng
Published: March 2018

A thorough understanding of the spatiotemporal dynamics of blood supply and tissue viability is of great importance in stroke researches. In the current study, vascular and cellular responses to focal ischemia were monitored with optical coherence tomography on chronic rat photothrombotic stroke model. The 3D mapping of blood perfusion and cellular scattering were achieved by analyzing the temporal dynamics and depth attenuation of intrinsic backscattered light respectively. Optical coherence tomography revealed that vessels of different types presented various spatial and temporal dynamics during the photothrombotic occlusion and the later recovery period. The large distal middle cerebral arteries presented a spontaneous recanalization and the small pial microvessels presented a reperfusion along with newly appeared vessels from the peripheral into the core area. The cortical capillary perfusion presented a weak recovery. Compared to the male group, the female rats showed a faster vascular recovery after photothrombotic. Moreover, the dynamic changes of the cellular scattering signal showed a high spatial and temporal correlation with the cortical capillary perfusion. Combined with well-designed photothrombotic stroke model and chronic optical window, optical coherence tomography imaging offers a unique approach to improve the understanding of stroke procedure and evaluate the treatment outcomes.
Longitudinal monitoring of mesoscopic cortical activity in a mouse model of microinfarcts reveals dissociations with behavioral and motor function
Authors: Balbi Matilde , Vanni Matthieu P , Vega Max J , Silasi Gergely , Sekino Yuki , Boyd Jamie D , LeDue Jeffrey M , Murphy Timothy H
Published: March 2018

Small vessel disease is characterized by sporadic obstruction of small vessels leading to neuronal cell death. These microinfarcts often escape detection by conventional magnetic resonance imaging and are identified only upon postmortem examination. Our work explores a brain-wide microinfarct model in awake head-fixed mice, where occlusions of small penetrating arterioles are reproduced by endovascular injection of fluorescent microspheres. Mesoscopic functional connectivity was mapped longitudinally in awake GCaMP6 mice using genetically encoded calcium indicators for transcranial wide-field calcium imaging. Microsphere occlusions were quantified and changes in cerebral blood flow were measured with laser speckle imaging. The neurodeficit score in microinfarct mice was significantly higher than in sham, indicating impairment in motor function. The novel object recognition test showed a reduction in the discrimination index in microinfarct mice compared to sham. Graph-theoretic analysis of functional connectivity did not reveal significant differences in functional connectivity between sham and microinfarct mice. While behavioral tasks revealed impairments following microinfarct induction, the absence of measurable functional alterations in cortical activity has a less straightforward interpretation. The behavioral alterations produced by this model are consistent with alterations observed in human patients suffering from microinfarcts and support the validity of microsphere injection as a microinfarct model.
Interregional mobility of talent in Spain: The role of job opportunities and qualities of places during the recent economic crisis
Authors: Sánchez-Moral Simón , Arellano Alfonso , Díez-Pisonero Roberto
Published: March 2018

This paper seeks to extend our knowledge of the drivers behind talented workers’ mobility within the Spanish urban system and the patterns they may follow. For this purpose, the stock and flows of creative workers (selected on the basis of either the industry-based or occupational approaches) are studied at different spatial scales while also considering the influence of local characteristics as a source of attracting and retaining forces. The study is based on the analysis of a quite novel longitudinal micro-database from the Spanish Social Security office. Under the conditions of lower mobility of creative workers compared with other geographical contexts – a trend worsened by the economic crisis – we show that job opportunities, especially in connection with workers’ social networks, emerge as the most influential attracting factor. Thus, beyond the classic idea that agglomeration economies benefit all residents, we found evidence that the biggest cities, and Madrid in particular, had become ‘escalator regions’, propelling the careers of young creative workers that had been attracted to them. On the contrary, the influence of urban amenities seems limited to the retention of talent. This research aims to contribute to dealing with the challenge of upgrading local productive forces after the economic crisis and to develop tailor-made talent attraction and retention strategies
Suburban revalorization: Residential infill and rehabilitation in Baltimore County’s older suburbs
Authors: Hanlon Bernadette , Airgood-Obrycki Whitney
Published: March 2018

This paper is a critical examination of redevelopment in the older suburbs of Baltimore County, Maryland between 2000 and 2014. Using exploratory spatial analysis techniques and qualitative methods, we identify the location of concentrated forms of suburban redevelopment, capturing incremental changes to single-family suburban homes in the form of residential rehabilitation, and new construction as well as larger-scale infill in the form of single-family subdivisions and apartments. We find that redevelopment among older suburbs is multifaceted, encompassing reinvestment in single-family housing in old elite residential suburban neighborhoods; the replacement of publicly subsidized apartment complexes with market rate, single-family dwellings in formerly industrial suburbs; the replacement of waterfront postwar housing with more expensive structures in formerly industrial suburbs; and the densification of older edge suburban core areas. The local planning regime has been instrumental in the redevelopment process across suburban types. Based on our findings, we suggest that suburban planners take a more active role in considering the potential direct and indirect displacement of low-income residents from redeveloped suburban spaces. This is imperative as inner-ring suburban devalorization occurs and suburban poverty grows.
A comparative study of using free radical generators in the testing of chosen oxidative stress parameters in the different types of cells
Authors: Miranowicz-Dzierżawska Katarzyna
Published: March 2018

The aim of this study was to assess whether there are differences between the results of determining oxidative stress markers obtained from different origin cell lines after exposure to chemicals generating free radicals. The studies considered two markers of oxidative stress: the level of thiobarbituric acid reactive substances (TBARS) and superoxide dismutase activity. The evaluation was performed in five cell lines: Chinese hamster ovary (CHO-9) cells, lung adenocarcinoma A549, macrophages RAW264.7, skin carcinoma cells A431, and keratinocytes HaCaT. Three compounds generating free radicals were used as a source of reactive oxygen/nitrogen: 2,2′-azobis-2-methyl-propanimidamide dihydrochloride (AAPH), sodium persulfate (SP), and 3-morpholinosydnonimine hydrochloride (SIN-1). The most appropriate cell line to assess the level of TBARS proved to be the murine macrophage cell line RAW 264.7. Equally, good performance was observed in the lung cancer cell line A549, but only when tested with AAPH and SP. In the case of measuring superoxide dismutase activity, it appeared that the most suitable cell line was also the RAW 264.7 line, although dispersion increased significantly at the highest concentrations of AAPH and SP measurements. When choosing a cell line to determine oxidative stress, the specificity of the stress-inducing compound and the parameter determined should be taken into consideration.
Morphology, crystallization, and thermal and mechanical properties of dynamic vulcanization EPDM/PP thermoplastic elastomer
Authors: Shi Min , Zhang Daohai , Zhu Jianhua , Shi Yinping , Sun Jing , Ji Yubi
Published: March 2018

Dynamically vulcanized thermoplastic olefin based on polypropylene (PP)/ethylene–propylene–diene (EPDM) with different dicumyl peroxide (DCP) content was prepared by twin-screw extruder. The effect of DCP content on gel content, crystallinity, and morphological, thermal, and mechanical properties of dynamically vulcanized EPDM/PP blends with different DCP content was investigated. The scanning electron microscopy was performed to evaluate the structure, as well as to characterize the morphology formed during dynamic vulcanization. The regular cross-linked EPDM particle uniformly distributed in PP matrix when the DCP content was from 0.3% to 0.9%. The crystallization behavior analysis indicated that the cross-linked EPDM promoted the nucleation process of PP, but with increase in DCP content, the percentage of crystallinity of the dynamically vulcanized EPDM/PP blends decreased due to the PP degradation. The tensile strength and elongation at break first increase and then decrease with increase in DCP content. When the DCP content was 0.9%, the tensile strength and elongation at break of dynamically vulcanized EPDM/PP blends were the largest. The gel content of dynamically vulcanized EPDM/PP blends first increased and then decreased with increasing DCP content. When the DCP content was 1.2%, the gel content of dynamically vulcanized EPDM/PP blends was maximum. The proper content range of DCP was from 0.6% to 1.2%.
Nursing Students’ Attitudes and Use of Holistic Therapies for Stress Relief
Authors: Kinchen Elizabeth V. , Loerzel Victoria
Published: March 2018

Purpose: The purpose of this study was to explore student nurses’ openness to using or recommending holistic therapies, the strategies they use to manage stress from school or work, and their perceptions of the impact of holistic therapies on personal health. Study Design: Qualitative component of a quasi-experimental, mixed-methods study. Methods: A convenience sample of undergraduate nursing students in a southeastern U.S. university completed baseline surveys, including demographics and three open-ended questions regarding attitudes toward holistic therapies and strategies used for stress management. Qualitative thematic analysis was undertaken to identify recurring themes in textual data. Findings: Students are open to using or recommending holistic therapies but identify lack of knowledge and lack of time as barriers to their practice. Among strategies used by student nurses to manage stress from school or work were physical activity, prayer and meditation, time management, distraction, socialization, artistic pursuits, animal interactions, and other activities. Themes describing holistic therapies’ impact on personal health were wholeness, self-empowerment, relaxation/restoration, and alternative/complement to traditional medicine. Conclusions: Findings indicate receptiveness by student nurses to the use of holistic therapies but point to the need for the inclusion of informational as well as experiential education on holistic therapies within nursing curricula.
Bilateral benefits
Authors: O’Donovan Dermot
Published: March 2018

This article explores the varied learning experiences among third-year students undertaking a structured work placement module in the furniture and wood manufacturing industries. Using situated learning theory, the article considers the outcomes of in-depth interviews with 10 students and offers an insight into the multifaceted interactions between ‘novices’ (students) and ‘experts’ in the workplace. Through the experiences and voices of students, the research uncovers evidence of two-way learning between the students and their work colleagues, particularly where the work environment and management support opportunities for knowledge and skills transfer. Three broad themes emerge from those interviews: (1) most students considered that workplaces facilitated opportunities for learning; (2) few barriers to learning were experienced by students; and (3) in most cases, students felt they had opportunities to introduce new skills. This qualitative piece of research underlines the importance for organizations to develop and promote the workplace as a ‘learning environment’ and to nurture new members so that they can contribute to learning, to the ultimate benefit of the whole organization. The findings highlight the positive role of curriculum design in accelerating the journey towards full participation for new members in a community of practice.
Numerical and experimental investigation of damage effect on a hemispherical parachute performance
Authors: Etemadi Fakhri , Mani Mahmoud , Kamali Moghadam Ramin
Published: March 2018

The effect of the canopy fabric damage on parachute performance has been investigated numerically and experimentally in the present paper. For this aim, first, flow structure around the parachute canopy has been studied for both damaged and undamaged parachutes. Then, the drag coefficient as the main characteristic of a parachute performance has been examined and compared experimentally and numerically in four Reynolds numbers. Experimental tests for undamaged and damaged canopies have been carried out in an open-circuit wind tunnel laboratory at the velocities 15, 20, 25, and 30 m/s. In order to measure the drag force, a valid tensile load-cell has been used. Also, the smoke flow visualization has been utilized to find the flow behavior at different regions of the parachute. For the numerical simulation, an incompressible pressure-based CFD code using the finite volume method has been applied to solve the complex turbulent flow field around the inflated parachute canopy. To increase accuracy of the numerical simulation, the permeability boundary condition on the parachute canopy has been implemented and its effects have been considered on the flow field. The numerical results indicate that the permeability assumption on the canopy makes desirable results compatible with the experimental ones. Moreover, comparison of the results between damaged and undamaged canopies demonstrates significant differences in the streamlines, pressure distributions, and drag coefficients. As the reliability is the main criterion for the parachute system, investigation on the damage effects would be useful and it has been considered in the present work.
A quadratic homotopy method for fuel-optimal low-thrust trajectory design
Authors: Pan Binfeng , Pan Xun , Ma Yangyang
Published: March 2018

Solving fuel-optimal low-thrust trajectory problems is a long-standing challenging topic, mainly due to the existence of discontinuous bang–bang controls and small convergence domain. Homotopy methods, the principle of which is to embed a given problem into a family of problems parameterized by a homotopic parameter, have been widely applied to address this difficulty. Linear homotopy methods, the homotopy functions of which are linear functions of the homotopic parameter, serve as useful tools to provide continuous optimal controls during the homotopic procedure with an energy-optimal low-thrust trajectory optimization problem as the starting point. However, solving energy-optimal problem is still not an easy task, particularly for the low-thrust orbital transfers with many revolutions or asteroids flyby, which is typically solved by other advanced numerical optimization algorithms or other homotopy methods. In this paper, a novel quadratic homotopy method, the homotopy function of which is a quadratic function of the homotopic parameter, is presented to circumvent this possible difficulty of solving the initial problem in the existing linear homotopy methods. A fixed-time full-thrust problem is constructed as the starting point of this proposed quadratic homotopy, the analytical solution of which can be easily obtained under a modified linear gravity approximation formulation. The criterion of energy-optimal problem is still involved in the homotopic procedure to provide continuous optimal controls until the original fuel-optimal problem is solved. Numerical demonstrations in an Earth to Venus rendezvous problem, a geostationary transfer orbit (GTO) to geosynchronous orbit (GEO) orbital transfer problem with many revolutions, and an Earth to Mars rendezvous problem with an asteroid flyby are presented to illustrate the applications of this proposed homotopy method.
Comparison between bolt clamping force and composite patches for repairing aircraft structures of aluminum alloy 2024-T3
Authors: Maleki HN , Chakherlou TN
Published: March 2018

Many parts used in various industries are subjected to multiaxial stresses during service phase, and since cracks can be a source of failure in the parts, it is extremely important to analyze the strength of cracked structures under multiaxial loads, and improve the structures fracture strength. In the present research, the effect of clamping force resulted from bolted pre-tension and composite patches on enhancing fracture strength of edge cracked rectangular samples made of aluminum-alloy 2024-T3 are evaluated both experimentally and theoretically. The cracked laboratory samples were tested using a modified version of Arcan fixture to develop pure tensile, pure shear, and mixed modes of loading. Further, finite-element simulations were utilized to find stress intensity factors to explain the experimental test results. The experimental results indicate a significant increase in the tensile strength of repaired parts by the bolt clamping and composite patches compared to simple cracked samples. Repaired samples with composite patch and bolt clamping exhibited up to 44% and 24% increase in tensile strength under pure tensile mode, respectively. However, in pure shear mode, the fracture strength increased to 18% and 9% by bolt clamping and composite patch, respectively.
Re-design of a uniplanar, monolateral external fixator
Authors: De Agostinis Massimiliano
Published: March 2018

This work deals with the structural analysis of screw clamps for external fixator devices. Screw clamps are widely used in external fixators as a means to connect the half-pins to the fixator body. The analysis is carried out by both numerical and experimental techniques, based on the case study of a clamp produced by Citieffe (Bologna, Italy). As a preliminary activity, the tribological parameters involved in the screw–clamp interaction have been characterized by means of a mixed finite element analysis and experimental procedure. Then, an assessment of the current design of the clamp has been carried out. A re-design has been proposed, which, based on some targeted geometrical modifications, allows achieving higher strength requirements with the same overall dimensions and type of materials. A higher load-bearing capability for a given size may allow the fixator to be used on a broader population. Finally, a list of good practices for the design of this kind of clamps has been proposed.
Securitization and Community-Based Protection Among Chin Refugees in Kuala Lumpur
Authors: McConnachie Kirsten
Published: March 2018

This article examines refugee-led community organizations among Chin refugees from Myanmar in Kuala Lumpur. It uses a structuration analysis that recognizes refugee-led organizations as complex governance entities engaged in a dynamic relationship with (among others) national policies of securitization of forced migration and international humanitarian governance. This approach expands the existing literature on the securitization of forced migration by exploring refugees’ lived experiences in a context of south–south migration. It expands the literature on community-based protection by going beyond recognizing the existence of refugee-led organizations to analyse their construction, constitution and consequences. Three primary areas of work by Chin refugee groups are analysed in relation to their immediate activity and longer term effects: organization (‘building ethnic unity in adversity’), documentation (‘asserting a bureaucratic identity’) and socialization (‘learning to be illegal’). These long-term effects indicate the possible impact of local protection activities on macrostructural processes such as identity construction and migration choices.
Polygamy, piousness, and the practice of medicine: Understanding Brigham Young and the predominance of female medical providers in early Utah
Authors: Donnenfeld Samuel R
Published: March 2018

The nineteenth century Mormon Prophet, Brigham Young, has long been lauded as progressive for sending dozens of Mormon women from the Utah territory to receive a formal medical education at The Women's Medical College of Pennsylvania. This manuscript comes to a contrary conclusion through close reading of diaries and journals created by these same women and the public speeches of the Prophet himself. These texts have historically been held up as evidence of Prophet Young's encouragement of women as physicians. This new interpretation of historical texts includes stringent study of his speeches, as they were originally reported, alongside later citations by historians from within the faith that decontextualized his words to fit the Church's predominant narrative. This manuscript concludes that, contrary to Church tradition, the historical record provides evidence of Young's desire to enforce limits and separations along traditional gender lines rather than showing an intent to change those cultural norms.
India’s Strategy in the Indian Ocean Region: A Critical Aspect of India’s Energy Security
Authors: Dasgupta Arnab
Published: March 2018

The Indian Ocean region serves as one of the busiest commercial as well as primary energy supply lines in the world. However, the energy traffic in the region is vulnerable to various strategic choke points. Any disruption caused either by sudden incidents or by sustained developments, thus, might create havoc for the entire global energy security. A unique geostrategic position has accrued India certain natural strategic advantages in the Indian Ocean. On the other hand, India depends essentially on the vital maritime energy supply lines in the region. Hence, ensuring the security of the Indian Ocean Region thus becomes India’s natural prerogative. India therefore needs to strategize its national maritime interest in the Indian Ocean as an uninterrupted energy supply is essential for national economic growth. This article seeks to identify the critical aspect of the Indian Ocean maritime supplies in India’s energy security and to find out India’s strategic imperative to that effect.
Recent Trends in Blood Pressure According to Economic Status: Korean National Health and Nutrition Examination Survey From 2005 to 2015
Authors: Shin Hyun-Young , Kang Hee-Taik
Published: March 2018

Our study assessed recent blood pressure (BP) trends according to economic status based on data from 2005 to 2015. In total, 56 873 participants were included and were defined as low, middle-low, middle-high, and high according to their house income quartile. In men, the mean systolic BP ( P < .001, β = −1.95; P = .01, β = −0.61; P = .35, β = −0.19; and P = .04, β = −0.47, from the low to the high group, respectively) and diastolic BP were decreased significantly in all groups ( P < .001, β = −2.18; P < .001, β = −0.77; P = .02, β = −0.40; and P < .001, β = −0.69, from the low to the high group, respectively). In women, the decreasing trends in systolic BP and diastolic BP were statistically significant except in the high-income group. In addition, the percentages of less-than-normotensive and less-than-hypertensive BP in both sexes and the control rate of hypertension on antihypertensive medications increased in all groups. Decreasing BP trends were observed in the recent decade and the gap in health inequities has been decreased, particularly in men in Korea.
Toward a Common Research Model: Leveraging Education Abroad Participation to Enhance College Graduation Rates
Authors: Haupt John , Ogden Anthony C. , Rubin Donald
Published: March 2018

This article calls for a common research model that can be replicated across institutions to systematically collect data on the impact of education abroad participation on college graduation rates. The ultimate goal of the proposed GRAD LEAP (Leveraging Education Abroad Participation for Graduation) model is to facilitate a meta-analysis yielding generalizable findings that can inform both institutional and national education abroad policy. The model consists of two levels of analysis: (a) a descriptive analysis to estimate and compare true graduation rates for education abroad participants and nonparticipants, and (b) a parametric analysis to estimate the value-added of education abroad participation, beyond factors already understood to impact graduation rates. The proposed research model can be expanded to include analysis of the impact of specific program factors on graduation rates (e.g., program duration, program type, student accommodation, etc.).
What Constitutes Rape? The Effect of Marital Status and Type of Sexual Act on Perceptions of Rape Scenarios
Authors: Adams-Clark Alexis A. , Chrisler Joan C.
Published: March 2018

Many people believe that rape is always perpetrated by a stranger and involves vaginal intercourse. To clarify perceptions of rape that do not follow traditional beliefs, participants were presented with a vignette that described a rape in which the marital status and sexual act were manipulated. Participants were then asked to assess the incident’s severity and the victim’s responsibility. Results indicated that there was no difference in perceptions between vignettes based on marital status. However, rapes involving vaginal intercourse were associated with lesser degrees of victim blame and minimization than were rapes involving forced oral sex or digital sex.
Stimulant Use in the Management of Mild Traumatic Brain Injury: A Qualitative Literature Review
Authors: Iaccarino Mary Alexis , Philpotts Lisa Liang , Zafonte Ross , Biederman Joseph
Published: March 2018

Objective: Mild traumatic brain injury (mTBI) often presents with cognitive complaints including difficulty with attention and concentration. As these symptoms resemble those of ADHD, stimulants may be a potential treatment for mTBI. This review evaluates the literature on the use of stimulants for the treatment of mTBI. Method: A systematic evaluation of the literature using six databases: Ovidmedline, Pubmed, psychINFO, CINAH, Embase, and Cochrane. Broad search terms were used and studies were included that evaluate the use of stimulant and stimulant-like medications in the mTBI population. Data extracted included stimulant type and dosing, symptoms targeted, outcomes, safety and tolerability, and if the study population had ADHD. Results: Nine studies were identified that met the inclusion criteria. Immediate release methylphenidate and amantadine were used for treatment. Methylphenidate had some impact on attention, fatigue, and depression. However, due to the limited number of studies and heterogeneity of study populations, symptoms targeted, and outcome measures used, meaningful conclusions regarding the effect of stimulants in mTBI could not be made. No study evaluated for the presence of ADHD within the study population, despite stimulants being the mainstay treatment for ADHD. Conclusion: PProspective studies on the use of stimulants in mTBI, that evaluate participants for a diagnosis of ADHD, are needed.
The Impact of Radiation on the Tumor Microenvironment: Effect of Dose and Fractionation Schedules
Authors: Arnold Kimberly M , Flynn Nicole J , Raben Adam , Romak Lindsay , Yu Yan , Dicker Adam P , Mourtada Firas , Sims-Mourtada Jennifer
Published: March 2018

In addition to inducing lethal DNA damage in tumor and stromal cells, radiation can alter the interactions of tumor cells with their microenvironment. Recent technological advances in planning and delivery of external beam radiotherapy have allowed delivery of larger doses per fraction (hypofractionation) while minimizing dose to normal tissues with higher precision. The effects of radiation on the tumor microenvironment vary with dose and fractionation schedule. In this review, we summarize the effects of conventional and hypofractionated radiation regimens on the immune system and tumor stroma. We discuss how these interactions may provide therapeutic benefit in combination with targeted therapies. Understanding the differential effects of radiation dose and fractionation can have implications for choice of combination therapies.
Changes in the Practice Patterns and Demographics of Ontario Dermatologists
Authors: Micieli Robert , Alhusayen Raed
Published: March 2018

Background:

Changes in the practice patterns and demographics of Canadian dermatologists remain largely unknown and would be helpful in assessing the future practice of dermatology across Canada.

Objective:

To assess changes in the population of Ontario dermatologists over time and the factors that influence their practice patterns, caseload, and the procedures they perform.

Methods:

A retrospective population-based analysis was performed using comprehensive administrative data on Ontario Health Insurance Plan insured dermatology visits and procedures from April 1, 2009, to March 31, 2015.

Results:

The number of dermatologists practicing in Ontario per 100 000 people increased from 1.52 (2009) to 1.62 (2014). During this period, the proportion of female dermatologists increased from 40% to 47%, and the proportion of male dermatologists decreased from 60% to 53%. The mean number of patient visits per dermatologist decreased from 6323 (2009) to 5877 (2014). Females saw a decrease from 4818 to 4181 visits, and males remained constant at 7274 to 7265 visits. Middle career dermatologists had more patient visits compared to those in their early or late career. A rural practice was associated with more patient visits compared to an urban one. The proportion of dermatologists providing nonemergency in-hospital patient services declined. The number of biopsies and malignant excisions performed increased.

Conclusions:

The number of dermatologists at the population level increased and the number of patient visits per dermatologist decreased. Career stage, physician sex, and practice location all affect the practice of dermatology. Future studies to assess underlying factors for these observations would be of value.
The Successful Treatment of Elephantiasis Nostras Verrucosa With Ablative Carbon Dioxide Laser
Authors: Robinson Caitlin G. , Lee Kory R. , Thomas Valencia D.
Published: March 2018

Background and Objective:

Elephantiasis nostras verrucosa (ENV) is a disfiguring skin condition that is difficult to treat. Existing treatment modalities serve to improve cosmesis or treat symptoms. Herein, we report a case of ENV with lymphocutaneous fistula successfully treated with ablative carbon dioxide laser.

Study Design/Patients and Methods:

A 57-year-old woman with biopsy-proven ENV with lymphocutaneous fistula was treated with ablative carbon dioxide laser to the symptomatic area of her right thigh in 3 treatment sessions over 6 months.

Results:

The patient had resolution of lymphocutaneous drainage as well as 90% improvement in the appearance of ENV lesions at the 1-month follow-up visit.

Conclusion:

Ablative carbon dioxide laser may provide cosmetic, symptomatic, and medical benefit for patients with localized ENV.