bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Nestin, a Selective Marker for Bone Marrow Derived Mesenchymal Stem Cells
Authors: Xie Liang , Zeng Xin , Hu Jing , Chen Qianming
Published: July 2015

Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiating into multiple cell lineages and contributing to tissue repair and regeneration. Characterization of the physiological function of MSCs has been largely hampered by lack of unique markers. Nestin, originally found in neuroepithelial stem cells, is an intermediate filament protein expressed in the early stages of development. Increasing studies have shown a particular association between Nestin and MSCs. Nestin could characterize a subset of bone marrow perivascular MSCs which contributed to bone development and closely contacted with hematopoietic stem cells (HSCs). Nestin expressing (Nes+) MSCs also play a role in the progression of various diseases. However, Nes+cells were reported to participate in angiogenesis as MSCs or endothelial progenitor cells (EPCs) in several tissues and be a heterogeneous population comprising mesenchymal cells and endothelial cells in the developing bone marrow. In this review article, we will summarize the progress of the research on Nestin, particularly the function of Nes+cells in bone marrow, and discuss the feasibility of using Nestin as a specific marker for MSCs.
Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography
Authors: Vinekar Anand , Mangalesh Shwetha , Jayadev Chaitra , Maldonado Ramiro S. , Bauer Noel , Toth Cynthia A.
Published: July 2015

Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.
On Some Fixed Point Results forH+-Type Contraction Mappings in Metric Spaces
Authors: Pathak Hemant Kumar , Rodríguez-López Rosana
Published: July 2015

We prove some fixed point theorems forH+-type multivalued contractive mappings in the setting of Banach spaces and metric spaces. The results provided allow recovering different well-known results.
Acetaminophen: Dose-Dependent Drug Hepatotoxicity and Acute Liver Failure in Patients
Authors: Jaeschke Hartmut
Published: July 2015

Background: Drug-induced liver injury is a rare but serious clinical problem. A number of drugs can cause severe liver injury and acute liver failure at therapeutic doses in a very limited number of patients (<1:10,000). This idiosyncratic drug-induced liver injury, which is currently not predictable in preclinical safety studies, appears to depend on individual susceptibility and the inability to adapt to the cellular stress caused by a particular drug. In striking contrast to idiosyncratic drug-induced liver injury, drugs with dose-dependent hepatotoxicity are mostly detected during preclinical studies and do not reach the market. One notable exception is acetaminophen (APAP, paracetamol), which is a safe drug at therapeutic doses but can cause severe liver injury and acute liver failure after intentional and unintentional overdoses. Key Messages: APAP overdose is responsible for more acute liver failure cases in the USA or UK than all other etiologies combined. Since APAP overdose in the mouse represents a model for the human pathophysiology, substantial progress has been made during the last decade in understanding the mechanisms of cell death, liver injury and recovery. More recently, emerging evidence based on mechanistic biomarker analysis in patients and studies of cell death in human hepatocytes suggests that most of the mechanisms discovered in mice also apply to patients. The rapid development of N-acetylcysteine as an antidote against APAP overdose was based on the early understanding of APAP toxicity in mice. However, despite the efficacy of N-acetylcysteine in patients who present early after APAP overdose, there is a need to develop intervention strategies for late-presenting patients. Conclusions: The challenges related to APAP toxicity are to better understand the mechanisms of cell death in order to limit liver injury and prevent acute liver failure, and also to develop biomarkers that better predict as early as possible who is at risk for developing acute liver failure with poor outcome.
Pathophysiology of Liver Fibrosis
Authors: Pinzani Massimo
Published: July 2015

Progressive accumulation of fibrillar extracellular matrix (ECM) in the liver is the consequence of reiterated liver tissue damage due to infective (mostly hepatitis B and C viruses), toxic/drug-induced, metabolic and autoimmune causes, and the relative chronic activation of the wound-healing reaction. The process may result in clinically evident liver cirrhosis and hepatic failure. Although cirrhosis is the common result of progressive fibrogenesis, there are distinct patterns of fibrotic development related to the underlying disorders causing the fibrosis. These different patterns of fibrogenic evolution are related to different factors and particularly: (1) the topographic localization of tissue damage, (2) the relative concentration of profibrogenic factors and (3) the prevalent profibrogenic mechanism(s). The mechanisms responsible for the fibrogenic evolution of chronic liver diseases can be summarized in three main groups: chronic activation of the wound-healing reaction, oxidative stress-related molecular mechanisms, and the derangement of the so-called ‘epithelial-mesenchymal' interaction leading to the generation of reactive cholangiocytes and peribiliary fibrosis. Most of the knowledge on the cell and molecular biology of hepatic fibrosis derives from in vitro studies employing culture of activated hepatic stellate cells isolated from rat, mouse or human liver. It is now evident that other ECM-producing cells, i.e. fibroblasts and myofibroblasts of the portal tract and circulating ‘fibrocytes', are likely to contribute to liver fibrosis. More recently, the attention is progressively shifting to the profibrotic microenvironment of the liver with increasing interest for the role of immune cells and specific subsets of macrophages regulating the progression or the regression of fibrosis, the role of intestinal microbiota and the influence of tissue stiffness. Other major areas of development include the role of tissue hypoxia and the establishment of an anaerobic proinflammatory environment and the influence of epigenetic modification in conditioning the progression of fibrosis.
Conservation Science and Contemporary Art: Thinking about Tenerife
Authors: A’Bear Luke , Hayward James Curtis , Root-Bernstein Meredith
Published: July 2015

Art has long been seen as a way to illustrate conservation science for public outreach, especially to children. However, art has a greater role to play as a partner in interdisciplinary practice. Here we explore four examples where early-career conservationists have used the production of artwork inspired by contemporary art movements to engage critically and emotionally through the formalisms of art with conservation issues on the island of Tenerife. The authors suggest that the production of art by conservationists and as conservation (and vice versa) is key to learning to translate between art and science, leading to broader interdisciplinarity.
Tabularia kobayasii: a new araphid diatom (Bacillariophyta, Fragilariaceae) from Japan
Authors: Suzuki Hidekazu , MITSUISHI Kyoko , NAGUMO Tamotsu , Tanaka Jiro
Published: July 2015

A new species of Tabularia, T. kobayasii, was found on seaweeds collected from several estuaries in the Central Pacific coast of Japan. Its morphology was examined by light and scanning electron microscopy; details are described herein. This araphid diatom is characterized by: 1) tufted or band-like colony; 2) valves lanceolate, flat with steep mantle, striae consisting of cribrate areolae, a wide lanceolate sternum, single rimoportula, and an occelulimbus at both poles; and 3) a cingulum consisting of a few non-fimbriated girdle bands including the valvocopula.
Interdecadal Difference of Interannual Variability Characteristics of South China Sea SSTs Associated with ENSO
Authors: Yang Yali , Xie Shang-Ping , Du Yan , Tokinaga Hiroki
Published: July 2015

The correlation between sea surface temperature (SST) and El Niño–Southern Oscillation (ENSO) persists into post-ENSO September over the South China Sea (SCS), the longest correlation in the World Ocean. Slow modulations of this correlation are analyzed by using the International Comprehensive Ocean–Atmosphere Dataset (ICOADS). ENSO’s influence on SCS SST has experienced significant interdecadal changes over the past 138 years (1870–2007), with a double-peak structure correlation after the 1960s compared to a single-peak before the 1940s. According to the ENSO correlation character, the analysis period is divided into four epochs. In epoch 3, 1960–83, the SST warming and enhanced precipitation over the southeastern tropical Indian Ocean, rather than the Indian Ocean basinwide warming, induce easterly wind anomalies and warm up the SCS in the summer following El Niño. Besides the Indian Ocean effect, during epochs 2 (1930–40) and 4 (1984–2007), the Pacific–Japan (PJ) pattern of atmospheric circulation anomalies helps sustain the SCS SST warming through summer (June–August) with easterly wind anomalies. The associated increase in shortwave radiation and decrease in upward latent heat flux cause the SCS SST warming to persist into the summer. Meanwhile, the rainfall response around the SCS to ENSO shows interdecadal variability, with stronger variability after the 1980s. The results suggest that both the remote forcing from the tropical Indian Ocean and the PJ pattern are important for the ENSO teleconnection to the SCS and its interdecadal modulations.
Temporal Downscaling of TRMM Rain-Rate Images Using Principal Component Analysis during Heavy Tropical Thunderstorm Seasons
Authors: Mahmud M. Rizaludin , Matsuyama Hiroshi , Hosaka Tetsuro , Numata Shinya , Hashim Mazlan
Published: July 2015

This paper examines the utility of principal component analysis (PCA) in obtaining accurate daily rainfall estimates from 3-hourly Tropical Rainfall Measuring Mission (TRMM) satellite data during heavy precipitation in a humid tropical environment. A large bias during heavy thunderstorms in humid tropical catchments is indicated by the TRMM satellite and is of profound concern because it is a conspicuous constraint for practical hydrology applications and requires proper treatment, particularly in areas with sparse rain gauges. The common procedure of calculating daily rainfall estimates by direct accumulation (DA) of a series of 3-hourly rainfall estimates caused a large bias because of temporal uncertainties, upscaling effects, and different mechanisms. In this study, PCA was used to transform correlated 3-hourly rain-rate images into a minimum effective principal component and to compute the corresponding rain-rate proportion based on correlation strength. This study was conducted on 91 rainy days of various intensity, acquired from three different years, during the wettest season on the eastern coast of peninsular Malaysia. Results showed that PCA reduced the bias and daily root-mean-square error by an average of 62% and 22%, respectively, compared with the DA approach. The PCA transformation was able to produce more precise daily rainfall estimates compared to the DA approach without the use of any rain gauge references. However, the performance was varied by the threshold selection and rainfall intensity. The results of this study indicate that PCA can be a useful tool in effective temporal downscaling of TRMM satellite data during heavy thunderstorm seasons in areas where rain gauges are sparse and satellite data are pivotal as a secondary source of rainfall data.
Pay dispersion and organizational innovation: The mediation effects of employee participation and voluntary turnover
Authors: Wang Taiyuan , Zhao Bin , Thornhill Stewart
Published: July 2015

Building on social comparison theory, we posit that a firm’s pay dispersion affects its innovation through employee participation and voluntary turnover. By analyzing data collected at both employee and organizational levels from 1419 firms, we found that pay dispersion had an inverted U-shaped effect on employee participation, which in turn enhanced innovation. Pay dispersion had a positive effect on voluntary turnover, which in turn impaired innovation. These findings contribute to research on economic inequity by revealing the mediation mechanisms of employee participation and voluntary turnover in the relationship between pay dispersion and organizational innovation.
Inequality, corporate legitimacy and the Occupy Wall Street movement
Authors: Shrivastava Paul , Ivanova Olga
Published: July 2015

This exploratory study examines legitimacy challenges to business spawned by growing inequalities. It uses aesthetic inquiry in the context of the Occupy Wall Street movement to understand the processes of organizational legitimation and delegitimation. By studying photos of slogans and placards from the Occupy Wall Street movement, we show how corporate and business legitimacy are challenged by the public. We identify different types of legitimacy challenges across organizational systems’ levels. We explore implications of these challenges for corporations and the use of aesthetic strategies as delegitimation signals by Occupy Wall Street protesters in order to express their support or discontent with existing norms, values and standards.
Bringing inequality back in: The economic inequality footprint of management and organizational practices
Authors: Riaz Suhaib
Published: July 2015

In this article, I argue for ‘bringing inequality back in’ to organizational research in order to investigate the role of management and organizational practices in macro-level economic inequality. To set an agenda in this area, I suggest considering three loci where the links between organizations and inequality may be observed: the organizational locus comprising the producer/employee, investor and consumer dimensions; the inter-organizational locus to help disentangle issues related to the distribution of economic rewards across value chains, large financial versus non-financial organizations, and across occupations and organizations in general; and socio-political system as a locus where issues related to social change, political influence and the institutional system may be unpacked. In addition, I suggest considering the link between organizations and inequality from other important vantage points: elites, demographics, global inequality and debt. I also briefly highlight issues related to data and analyses. Throughout, I discuss the contributions of the five articles in the special issue and how they push us towards this agenda. Finally, I suggest that it may be helpful to think of an ‘inequality footprint’ of management and organizational practices, potentially leading organizations to reduce and reverse this footprint and ensure that economic benefits reach wider society.
An Examination of the Situational Factors Associated With the Misuse of Prescription Analgesics Among College Students
Authors: Gallucci Andrew R. , Wynveen Chris , Hackman Christine , Meyer Andrew , Usdan Stuart
Published: July 2015

The current study examined the effect that students’ educational environment has on the prevalence and motivations associated with the misuse of prescription analgesics (MPA). A sample of 893 undergraduate students was recruited from one religiously affiliated private university and one public university in the Southern United States. Participants completed an in-class survey assessing MPA-related behavior and their associated motivations. Results indicated that students attending the religiously affiliated university displayed lower rates of MPA. Multivariate analyses revealed that a positive drug abuse screening, prescription status, and grade point average are the strongest predictors of past-year MPA for both schools. Some motivations for medical misuse differed significantly between campuses. Implications as to how these differences can inform programs aimed at the reduction of prescription analgesic abuse are discussed.
Collagen immobilization on ultraviolet light-treated poly(ethylene terephthalate)
Authors: Drobota Mioara , Aflori Magdalena , Gradinaru Luiza M. , Coroaba Adina , Butnaru Maria , Vlad Stelian , Vasilescu Dan S.
Published: July 2015

The present article is focused on the studies regarding the effects of ultraviolet (UV) light on poly(ethylene terephthalate) (PET) films surfaces using scanning electron microscopy (SEM), Fourier transform infrared, X-ray photoelectron spectrometry (XPS), and atomic force microscopy (AFM) measurements, subsequent to collagen immobilization. UV treatment influences the surface energy of polymers as the result of the polymer chain breaking, followed by insertion of oxygen-containing functional groups. Accordingly, after UV light treatment, collagen was adsorbed on the PET surfaces in different proportions. Significant changes in the surface topography appeared after collagen immobilization on UV-treated PET films, and they were put in evidence by SEM and tapping-mode AFM experiments. XPS measurements demonstrated the adsorption of collagen on PET UV light-altered surfaces by increasing of nitrogen content. The cytocompatibility tests using stem cells have shown good results for all treated polymers.
Tensor product model-based control of morphing aircraft in transition process
Authors: He Zhen , Yin Ming , Lu Yu-ping
Published: July 2015

Morphing aircraft can change their shapes in order to acquire enhanced flight performance. In the transition process of shape change, the aerodynamics and dynamics of aircraft would change dramatically, and the aircraft is a time-varying and highly nonlinear system. This article presents a tensor product (TP) modeling method and a TP model-based control design method for a kind of morphing aircraft in transition process. First, a new linear parameter varying (LPV) modeling method is proposed to model the longitudinal dynamics of a kind of morphing aircraft undergoing large shape change. This LPV modeling method does not need trim map and numerical calculation. Then, the LPV model is transformed into a TP type polytopic model. Furthermore, the TP model is augmented by a slow reference dynamics of flight speed. Based on the augmented TP model, a TP model-based LPV controller is designed by using parallel-distributed-compensation (PDC) control techniques and regional pole placement techniques. Finally, simulations are performed on a variable-sweep morphing aircraft undergoing large-scale changes in both shape and flight speed, and the results demonstrate the effectiveness of the proposed methodology.
Integrating Work and Education
Authors: Raina Vinod
Published: July 2015

This essay examines the recommendations on vocationalised education contained in the NCF 2005 and suggests that its definition is deeply entrenched within the ideology which promotes it. In India, the challenge to it is more political than pedagogical, and surprisingly comes mainly from the Dalits. There is therefore a need to demonstrate that it can be emancipatory in both a class and caste sense.
School Science and Students in Rural India
Authors: Sharma Ajay
Published: July 2015

This paper presents an ethnographic case study of Class VIII students of a government rural middle school in the state of Madhya Pradesh. It analyses their experiences and knowledge of their local material world, and contrasts them with a critique of school science to understand how well school science corresponds with learning needs and resources of students in rural India. It highlights the adverse implications of the gap between the learning needs and resources that students bring to the science classroom, and the learning opportunities that school science offers. It also argues for a more culturally responsive science education that preserves hopes for personal and societal peaceful progressive change through education for underprivileged students in India.
Early Literacy Project - Explorations and Reflections Part 2
Authors: Jayaram Keerti
Published: July 2015

The Early Literacy Project is an intervention to support Hindi learners. In the first part of this paper, the theoretical concerns were discussed. In this second part, the experiences of working within classrooms of a few government schools is presented. These included linguistically controlled interventions for beginners, which aimed to build strong foundations in phonological awareness, orthographic knowledge and skills of meaning constructions in keeping with natural predispositions and the out-of-school languages and experiences of learners. The experiences of setting up ‘active print rich classrooms’ is also discussed. Although the responses from the classrooms have been encouraging, systemic mechanisms are required for sustaining these interventions.
Teacher Empowerment
Authors: Batra Poonam
Published: July 2015

The paper argues that teacher empowerment is a necessary condition for quality education and social transformation, but this has been systematically neglected by policy makers and educational planners in India. The agency of the teacher is important in realising larger social goals and in the context of the recent legislation to make the Right to Education a Fundamental Right. The curriculum design of the BElEd programme offered by the University of Delhi is discussed in detail to illustrate the potential of achieving this through pre-service teacher education.
Sport and communities in Luxembourg: The influence and role of sportive women in a small metropolis
Authors: Lamour Christian , Vanni Laureen
Published: July 2015

Sport, since the late 19th century, has been and remains one of the most continuous and enduring human activities. It is also known as a cultural practice mainly dominated by men. The objective of this article, based on a quantitative analysis of cultural practices in Luxembourg, is to question interactions between sport, community-building and gender. It is hypothesized that sport in multicultural metropolises is a hobby generated not only by men but also by women who are involved in a cosmopolitan and secular society.
Efficiency and effectiveness of implicit and explicit approaches for the analysis of shape-memory alloy bodies
Authors: Scalet Giulia , Auricchio Ferdinando , Hartl Darren J
Published: July 2015

The increasing number of applications incorporating shape-memory alloy (SMA) components motivates the development of three-dimensional constitutive models to enhance their analysis and design. These models only reach their full utility if they are then implemented into numerical (e.g. often finite-element-based) frameworks. The present article addresses a topic rarely considered in the myriad of SMA computational analysis works in the literature: the analysis of the time and accuracy of implementation options. In particular, this work proposes to compare the performance of the implicit and explicit integration methods for two common three-dimensional phenomenological constitutive models: (i) the model by Lagoudas et al.; and (ii) the model by Auricchio et al. available in all installations of Abaqus. In doing so, the present work develops and implements an explicit algorithm for the model by Lagoudas et al. for the first time. The investigated models are compared in a chosen benchmark boundary value problem analysis considering both thermally induced actuation and isothermal stress-induced transformation of an SMA beam. The performance of the methods in terms of analysis time and parallelization efficiency are also investigated.
Exploring price fluctuations across different online travel agencies
Authors: Sun Sunny , Law Rob , Tse Tony
Published: July 2015

The Internet has changed the traditional behavior of customers when purchasing tourism-related products, especially when reserving hotel rooms online. Online travel agencies (OTAs) that offer Web-based hotel room reservation services have proliferated in recent years. This study explores fluctuations in hotel room rates offered by OTAs, a topic that has yet to be fully explored. The results show that ‘last-minute sales mode’ is less frequently adopted among different OTAs at present. Moreover, these agencies even charge the same room rate regardless of the hotel rating (e.g. 5-star, 4.5-star, or 4-star). Furthermore, bundle pricing is more cost-effective than purchasing separate items. Finally, most OTAs have failed to keep their promise of a ‘best rate guarantee’. These findings can help hotel managers improve their strategic management, ensure rate parity among various OTAs, and assist customers in reserving hotel rooms online.
“Hoping for Greatness”
Authors: Woodfield Casey , Jung Eunyoung , Ashby Christine
Published: July 2015

This research explores the stage of novicity in communicative partnerships between new facilitators and the individuals with disabilities who use supported typing as their primary method of communication with whom they work. We interviewed novice and experienced facilitators, and typers who have recently worked with new facilitators to examine not only the series of processes through which novice facilitators experience and learn to support typing but also typers’ responses to those experiences. We draw connections to sign language interpreters and paraprofessionals to highlight the complexity of providing communication access and support. Two key tracks of talk emerged—one centered on skills and the other on relationships—which we lay out in a discussion of typers’ and facilitators’ perspectives on expectations, training, trust, and agency. Our results suggest the critical nature of establishing individualized expectations for and by both typers and facilitators, as well as the importance of working through the distinctive experiences brought forth in this period of novicity, as fundamental elements of developing communication partnerships.
Special Education Directors’ Views of Community-Based Vocational Instruction
Authors: Pickens Julie L. , Dymond Stacy K.
Published: July 2015

The purpose of this study was to investigate the views of special education directors toward community-based vocational instruction (CBVI). Participants included a non-proportional random sample of 47 directors from one state who completed an online or paper-based survey. Independent variables were directors’ years of experience, geographic location, whether the district provided CBVI in the summer, and the curriculum of students who participated in CBVI. Data were analyzed using descriptive and inferential statistics along with a content analysis of open-ended questions. Results indicate that respondents support the use of CBVI and experience few barriers to implementation. Insufficient staff and inadequate public transportation were the highest rated barriers. Views regarding the intensity with which CBVI should be provided and the age and types of students who should receive CBVI differed from practices recommended in the field. Significant group findings were evident for the variables of years of experience and curriculum of students who participated in CBVI.
Residential concentration and marital behaviors of Muslim Chinese
Authors: Mu Zheng , Wu Xiwei
Published: July 2015

This article examines how the marital behaviors of Hui Muslims respond to varying residential concentrations of Hui. Specifically, the marriage patterns indicating responses to local demographic availability of marriageable Hui and adherence to two Islamic norms – universal marriage and endogamy – were explored. Marriage market conditions were measured by local concentrations of Hui and we estimate discrete-time hazard models of marital outcomes using the China 2005 1% inter-census survey. The results show that in places with higher Hui concentrations, Hui tend to have higher marriage rates, to marry earlier, and to marry more endogamously. Conditional on being married, the logged odds of exogamy over endogamy are significantly lower in places with higher Hui concentrations; nevertheless, if exogamy is treated as an alternative to being single, the coefficient of the logged odds of exogamy over being single is significantly negative only for women. This suggests coexistence and competition between the two Islamic norms. Moreover, women have consistently higher marriage rates than men, regardless of Hui concentration. This suggests that women are universally more strictly constrained by the norm of universal marriage than men are. However, men show more variation in marriage rates, suggesting that they are more responsive to changes in Hui concentrations. Men and women are equally restricted by the norm of endogamy.
Microstructure, thermodynamics and compressive properties of AlCrCuNixTi (x = 0, 1) high entropy alloys
Authors: Wang X.-R. , He P. , Lin T.-S. , Wang Z.-Q.
Published: July 2015

Two equiatomic high entropy alloys, AlCrCuNixTi ( x = 0, 1), were prepared by an arc furnace. Their microstructure, thermodynamics and compressive properties were investigated in as-cast state. The AlCrCuTi alloy consists of a face centred cubic (fcc) phase, two body centred cubic (bcc) phases and an Al4Cu9-like phase, while the AlCrCuNiTi alloy contains an fcc phase and two bcc phases. Thermodynamic expressions based on mixing enthalpy matrix facilitate the thermodynamic calculation. The element Cr takes severe segregation during solidification and forms Cr rich phases in both alloys. The addition of Ni to the AlCrCuNiTi alloy inhibits the formation of intermetallic compounds and enhances the yield strength, compressive strength and ultimate strain, but degrades Vickers hardness.
Localized vs. synchronized exports across a highly renewable pan‐European transmission network
Authors: Rodriguez Rolando A. , Dahl Magnus , Becker Sarah , Greiner Martin
Published: July 2015

Background

A future, highly renewable electricity system will be largely based on fluctuating renewables. The integration of wind and solar photovoltaics presents a major challenge. Transmission can be used to lower the need for complementary generation, which we term backup in this article.

Methods

Generation data based on historical weather data, combined with real load data, determine hourly mismatch timeseries for all European countries, connected by physical power flows. Two localized export schemes determining the power flows are discussed, which export only renewable excess power, but no backup power, and are compared to a synchronized export scheme, which exports renewable excess power and also backup power.

Results

Compared to no or very limited power transmission, unconstrained power flows across a highly renewable pan‐European electricity network significantly reduce the overall amount of required annual backup energy, but not necessarily the required backup capacities.

Conclusions

The reduction of the backup capacities turns out to be sensitive to the choice of export scheme. Results suggest that the synchronized export of local backup power to other countries is important to significantly save on installed backup capacities.
Effects of Ramadan fasting on glucose homeostasis and adiponectin levels in healthy adult males
Authors: Gnanou Justin V. , Caszo Brinnell A. , Khalil Khalifah M. , Abdullah Shahidah L. , Knight Victor F. , Bidin Mohd Z.
Published: July 2015

Background

Adiponectin is a hormone secreted by adipocytes during the fasting phase of the fast-fed cycle. Ramadan fasting involves prolonged fasting for up to twelve hours and thus could lead to increased secretion of adiponectin by adipocytes. However, studies on the role of adiponectin on glucose and body weight homeostasis during Ramadan fasting is still a matter of controversy. Thus the specific aim of this study was to assess the effect of fasting during Ramadan on the adiponectin levels, body weight and glucose homeostasis in healthy male Malaysian subjects.

Methods

Twenty healthy male (19–23 years) Muslim subjects were followed up during the fasting month of Ramadan. Anthropometry and blood samples were taken one week before and during the fourth week of fasting. Plasma glucose, insulin and adiponectin were estimated and insulin sensitivity indices were estimated using the Homeostasis Model Assessment.

Results

Subjects experienced a significant decrease in body weight (2.4 %, p < 0.001) and body mass index (5.5 %, p < 0.01). There was also a significant decrease of 12.3 %, 52.8 % and 45.6 % of plasma glucose, insulin and adiponectin respectively (p < 0.01). The drop in adiponectin was positively correlated with the decrease in body weight (r = 0.45, p < 0.05). There was also a significant increase in insulin sensitivity and a decrease in insulin resistance (p < 0.01).

Conclusions

These results indicate that Ramadan fasting in young healthy individuals has a positive impact on the maintenance of glucose homeostasis. It also shows that adiponectin levels dropped along with significant loss in weight. We feel caloric restriction during the Ramadan fasting is in itself sufficient to improve insulin sensitivity in healthy individuals.
Examining the Impact of Question Surface Features on Students’ Answers to Constructed-Response Questions on Photosynthesis
Authors: Weston Michele , Haudek Kevin C. , Prevost Luanna , Urban-Lurain Mark , Merrill John
Published: July 2015

One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of two question prompts. We asked four versions of the question with different combinations of the two plant species and order of prompts in an introductory cell biology course. We found that there was not a significant difference in the content of student responses to versions of the question stem with different species or order of prompts, using both computerized lexical analysis and expert scoring. We conducted 20 face-to-face interviews with students to further probe the effects of question wording on student responses. During the interviews, we found that students thought that the plant species was neither relevant nor confusing when answering the question. Students identified the prompts as both relevant and confusing. However, this confusion was not specific to a single version.
Helping Struggling Students in Introductory Biology: A Peer-Tutoring Approach That Improves Performance, Perception, and Retention
Authors: Batz Zachary , Olsen Brian J. , Dumont Jonathan , Dastoor Farahad , Smith Michelle K.
Published: July 2015

The high attrition rate among science, technology, engineering, and mathematics (STEM) majors has long been an area of concern for institutions and educational researchers. The transition from introductory to advanced courses has been identified as a particularly “leaky” point along the STEM pipeline, and students who struggle early in an introductory STEM course are predominantly at risk. Peer-tutoring programs offered to all students in a course have been widely found to help STEM students during this critical transition, but hiring a sufficient number of tutors may not be an option for some institutions. As an alternative, this study examines the viability of an optional peer-tutoring program offered to students who are struggling in a large-enrollment, introductory biology course. Struggling students who regularly attended peer tutoring increased exam performance, expert-like perceptions of biology, and course persistence relative to their struggling peers who were not attending the peer-tutoring sessions. The results of this study provide information to instructors who want to design targeted academic assistance for students who are struggling in introductory courses.
Improvements from a Flipped Classroom May Simply Be the Fruits of Active Learning
Authors: Jensen Jamie L. , Kummer Tyler A. , Godoy Patricia D. d. M.
Published: July 2015

The “flipped classroom” is a learning model in which content attainment is shifted forward to outside of class, then followed by instructor-facilitated concept application activities in class. Current studies on the flipped model are limited. Our goal was to provide quantitative and controlled data about the effectiveness of this model. Using a quasi-experimental design, we compared an active nonflipped classroom with an active flipped classroom, both using the 5-E learning cycle, in an effort to vary only the role of the instructor and control for as many of the other potentially influential variables as possible. Results showed that both low-level and deep conceptual learning were equivalent between the conditions. Attitudinal data revealed equal student satisfaction with the course. Interestingly, both treatments ranked their contact time with the instructor as more influential to their learning than what they did at home. We conclude that the flipped classroom does not result in higher learning gains or better attitudes compared with the nonflipped classroom when both utilize an active-learning, constructivist approach and propose that learning gains in either condition are most likely a result of the active-learning style of instruction rather than the order in which the instructor participated in the learning process.
The Best of Both Worlds: Building on the COPUS and RTOP Observation Protocols to Easily and Reliably Measure Various Levels of Reformed Instructional Practice
Authors: Lund Travis J. , Pilarz Matthew , Velasco Jonathan B. , Chakraverty Devasmita , Rosploch Kaitlyn , Undersander Molly , Stains Marilyne
Published: July 2015

Researchers, university administrators, and faculty members are increasingly interested in measuring and describing instructional practices provided in science, technology, engineering, and mathematics (STEM) courses at the college level. Specifically, there is keen interest in comparing instructional practices between courses, monitoring changes over time, and mapping observed practices to research-based teaching. While increasingly common observation protocols (Reformed Teaching Observation Protocol [RTOP] and Classroom Observation Protocol in Undergraduate STEM [COPUS]) at the postsecondary level help achieve some of these goals, they also suffer from weaknesses that limit their applicability. In this study, we leverage the strengths of these protocols to provide an easy method that enables the reliable and valid characterization of instructional practices. This method was developed empirically via a cluster analysis using observations of 269 individual class periods, corresponding to 73 different faculty members, 28 different research-intensive institutions, and various STEM disciplines. Ten clusters, called COPUS profiles, emerged from this analysis; they represent the most common types of instructional practices enacted in the classrooms observed for this study. RTOP scores were used to validate the alignment of the 10 COPUS profiles with reformed teaching. Herein, we present a detailed description of the cluster analysis method, the COPUS profiles, and the distribution of the COPUS profiles across various STEM courses at research-intensive universities.
Research-Based Implementation of Peer Instruction: A Literature Review
Authors: Vickrey Trisha , Rosploch Kaitlyn , Rahmanian Reihaneh , Pilarz Matthew , Stains Marilyne
Published: July 2015

Current instructional reforms in undergraduate science, technology, engineering, and mathematics (STEM) courses have focused on enhancing adoption of evidence-based instructional practices among STEM faculty members. These practices have been empirically demonstrated to enhance student learning and attitudes. However, research indicates that instructors often adapt rather than adopt practices, unknowingly compromising their effectiveness. Thus, there is a need to raise awareness of the research-based implementation of these practices, develop fidelity of implementation protocols to understand adaptations being made, and ultimately characterize the true impact of reform efforts based on these practices. Peer instruction (PI) is an example of an evidence-based instructional practice that consists of asking students conceptual questions during class time and collecting their answers via clickers or response cards. Extensive research has been conducted by physics and biology education researchers to evaluate the effectiveness of this practice and to better understand the intricacies of its implementation. PI has also been investigated in other disciplines, such as chemistry and computer science. This article reviews and summarizes these various bodies of research and provides instructors and researchers with a research-based model for the effective implementation of PI. Limitations of current studies and recommendations for future empirical inquiries are also provided.
Aspect ratio histograms of 3D ellipsoids and 2D ellipses — Analytical relations and numerical examples
Authors: Landrø Martin
Published: July 2015

A typical way of characterizing rocks, composite materials, or human tissue is to extract aspect ratio histograms. A common assumption for this type of analysis is that the sample is composed of several grains or building elements that have a similar shape. Among various shapes, the ellipsoid is very common. In practice, such detailed analysis is performed on 2D cuts or slices through the material. It is intuitive that there is a difference between a 2D aspect ratio histogram and the corresponding 3D histogram. I have derived simple equations that can be used to transform from 3D to 2D and also from 2D to 3D, assuming that the two shortest axes in the ellipsoid were equal. For the general case, when all axes were different, an approximate equation was derived. All equations were compared with stochastic numerical simulations of cutting a 3D ellipsoid by an arbitrary random number of planes. It was determined that in the general case, the shortest aspect ratio would dominate the 2D histograms and that it was practically impossible to detect the highest aspect ratio from 2D planar cuts.
Salt tectonics of the eastern border of the Leinetal Graben, Lower Saxony, Germany, as deduced from seismic reflection data
Authors: Tanner David C. , Musmann Patrick , Wawerzinek Britta , Buness Hermann , Krawczyk Charlotte M. , Thomas Rüdiger
Published: July 2015

To study the salt-related tectonic evolution of the Leinetal Graben, located in the southernmost part of the Central European Basin (CEB) in Germany, we acquired two (1.8- and 3.2-km-long) P-wave reflection seismic profiles across the eastern border faults of the graben. The profiles were acquired with a minivibro along a 1.8-km active spread, densely sampled by geophones spaced at 5 m. The resulting sections showed stratigraphic and fault geometries to a depth of approximately 1200 m. Using two deep boreholes for calibration, we interpreted Mesozoic strata down to the Triassic Zechstein salt and the faults that affected these strata. We recognized two sets of faults: (1) steep, planar faults that are closely clustered and terminated in the Zechstein salt (type 1) and (2) shallow faults that connected between the first set of faults and have very variable dip, depending on the lithology they intersect (type 2). We discovered that the faults do not cross cut the Zechstein salt, but instead they decoupled at this layer. The present-day structure can be interpreted using a two-stage tectonic model. Either there was “downbuilding” during the Triassic, “rafting” of lower Buntsandstein blocks on the Zechstein salt, or both. This resulted in a proto-Leinetal Graben Zechstein diapir surrounded by depocenters. During the Late Cretaceous/Early Tertiary inversion phase, the diapir collapsed, first along type 1 steep faults that detached in the salt layer, and later along type 2 faults; the latter formed as the result of continued extension. Recognition of such early halokinesis was important for the understanding of the behavior of the salt in the CEB and salt tectonics in general.
Radioactive Iodine Therapy Did Not Significantly Increase the Incidence and Recurrence of Subsequent Breast Cancer
Authors: Ahn Hwa Young , Min Hye Sook , Yeo Yohwan , Ma Seung Hyun , Hwang Yunji , An Jee Hyun , Choi Hoon Sung , Keam Bhumsuk , Im Seock-Ah , Park Do Joon , Park In Ae , Noh Dong-Young , Youn Yeo-Kyu , Chung June-Key , Cho Bo Youn , Park Sue K. , Park Young Joo
Published: July 2015

Context:

Previous studies on the extent to which radioactive iodine (RAI) therapy for thyroid cancer increases the risk of subsequently developing breast cancer have given conflicting results.

Objective:

This study aimed to evaluate the effect of RAI treatment on breast cancer development and recurrence among female patients with primary thyroid cancer.

Design:

This was a retrospective cohort study. The risk of subsequent breast cancer associated with RAI and its dose in hazard ratios (HRs) with 95% confidential intervals (CIs) were calculated using time-dependent Cox proportional hazard models.

Patients:

A total of 6150 patients with thyroid cancer enrolled between 1973 and 2009 were followed until December 2012. Of these, 3631 (59.0%) received RAI therapy. During the follow-up period, 99 primary breast cancers were diagnosed.

Main Outcome Measure:

Risk of breast cancer development according to RAI therapy and RAI dose during treatment for primary thyroid cancer.

Results:

RAI therapy did not significantly increase the incidence of subsequent breast cancer among female patients (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.22–1.06) when a 2-year latency period was accounted for. High-dose RAI (≥120 mCi) was associated with a reduced incidence of subsequent breast cancer (HR, 0.17; 95% CI, 0.05–0.62) in the cohort with a 2-year latency period.

Conclusions:

The long-term follow-up results of this study suggest that RAI treatment for patients with thyroid cancer may not increase the risk or recurrence of breast cancer.