bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential parameters between cytosolic 2‐Cys peroxiredoxins, PRDX1 and PRDX2
Authors: Dalla Rizza Joaquín , Randall Lía M. , Santos Javier , Ferrer‐Sueta Gerardo , Denicola Ana
Published: October 2018

Peroxiredoxins are thiol‐dependent peroxidases that function in peroxide detoxification and H2O2 induced signaling. Among the six isoforms expressed in humans, PRDX1 and PRDX2 share 97% sequence similarity, 77% sequence identity including the active site, subcellular localization (cytosolic) but they hold different biological functions albeit associated with their peroxidase activity. Using recombinant human PRDX1 and PRDX2, the kinetics of oxidation and hyperoxidation with H2O2 and peroxynitrite were followed by intrinsic fluorescence. At pH 7.4, the peroxidatic cysteine of both isoforms reacts nearly tenfold faster with H2O2 than with peroxynitrite, and both reactions are orders of magnitude faster than with most protein thiols. For both isoforms, the sulfenic acids formed are in turn oxidized by H2O2 with rate constants of ca 2 × 103 M−1 s−1 and by peroxynitrous acid significantly faster. As previously observed, a crucial difference between PRDX1 and PRDX2 is on the resolution step of the catalytic cycle, the rate of disulfide formation (11 s−1 for PRDX1, 0.2 s−1 for PRDX2, independent of the oxidant) which correlates with their different sensitivity to hyperoxidation. This kinetic pause opens different pathways on redox signaling for these isoforms. The longer lifetime of PRDX2 sulfenic acid allows it to react with other protein thiols to translate the signal via an intermediate mixed disulfide (involving its peroxidatic cysteine), whereas PRDX1 continues the cycle forming disulfide involving its resolving cysteine to function as a redox relay. In addition, the presence of C83 on PRDX1 imparts a difference on peroxidase activity upon peroxynitrite exposure that needs further study.
Modulating long‐range energetics via helix stabilization: A case study using T4 lysozyme
Authors: Rosemond Sabriya N. , Hamadani Kambiz M. , Cate Jamie H. D. , Marqusee Susan
Published: October 2018

Cooperative protein folding requires distant regions of a protein to interact and provide mutual stabilization. The mechanism of this long‐distance coupling remains poorly understood. Here, we use T4 lysozyme (T4L*) as a model to investigate long‐range communications across two subdomains of a globular protein. T4L* is composed of two structurally distinct subdomains, although it behaves in a two‐state manner at equilibrium. The subdomains of T4L* are connected via two topological connections: the N‐terminal helix that is structurally part of the C‐terminal subdomain (the A‐helix) and a long helix that spans both subdomains (the C‐helix). To understand the role that the C‐helix plays in cooperative folding, we analyzed a circularly permuted version of T4L* (CP13*), whose subdomains are connected only by the C‐helix. We demonstrate that when isolated as individual fragments, both subdomains of CP13* can fold autonomously into marginally stable conformations. The energetics of the N‐terminal subdomain depend on the formation of a salt bridge known to be important for stability in the full‐length protein. We show that the energetic contribution of the salt bridge to the stability of the N‐terminal fragment increases when the C‐helix is stabilized, such as occurs upon folding of the C‐terminal subdomain. These results suggest a model where long‐range energetic coupling is mediated by helix stabilization and not specific tertiary interactions.
Raman Spectroscopy on Surface Phonons of Si(hhk) Surfaces Modified by Au Submonolayers
Authors: Speiser Eugen , Plaickner Julian , Chandola Sandhya , Esser Norbert , Halbig Benedikt , Geurts Jean
Published: October 2018

Raman spectroscopy has evolved to a sensitive tool for analyzing vibration modes of ordered (sub)monolayers of metal adatoms on semiconductor surfaces, which are typical systems for electron correlation effects. We report on the in situ UHV Raman analysis of self‐organized Au submonolayers on nominal Si(111) surfaces, as well as on vicinal Si(553), Si(775), and Si(557). For the two‐dimensional Au‐ and the one‐dimensional Au‐(5 × 2) reconstruction several specific Raman peaks in the spectral range below 200 cm−1 are assigned to Au‐dominated vibration modes, while Si‐step‐edge vibration modes around 400 cm−1 are fingerprints of the substrate orientation.
Continuum embeddings in condensed‐matter simulations
Authors: Andreussi Oliviero , Fisicaro Giuseppe
Published: October 2018

Continuum models have a long tradition in computational chemistry, where they have provided a compact and efficient way to characterize environment effects in quantum‐mechanical simulations of solvated systems. Fattebert and Gygi pioneered the development of continuum dielectric embedding schemes for periodic systems and their seamless extension toward molecular dynamics simulations. Following their work, continuum embedding approaches in condensed‐matter simulations have thrived. The possibility to model wet and electrified interfaces, with a reduced computational overhead with respect to isolated systems, is opening new perspectives in the characterization of materials and devices. Important applications of these new techniques are in the field of catalysis, electro‐chemistry, electro‐catalysis, etc. Here we will address the main physical and computational aspects of continuum embedding schemes recently developed for condensed‐matter simulations, underlying their peculiarities and their differences with respect to the quantum‐chemistry state‐of‐the‐art.
The interplay of competition and cooperation
Authors: Hoffmann Werner , Lavie Dovev , Reuer Jeffrey J. , Shipilov Andrew
Published: October 2018

Research streams on competition and cooperation are central to the field of strategic management but have evolved independently. The emerging literature on coopetition has brought attention to the phenomenon of simultaneous competition and cooperation, yet the interplay between the two has remained under‐researched. We offer a roadmap for studying this interplay, which identifies some of its antecedents and consequences, highlights debates concerning the nature of competition and cooperation and the association between the two, and directs attention to the tension between competition and cooperation and the alternative approaches for managing this tension. We discuss the broader implications of the interplay, note some intriguing open questions, offer directions for future research, and present an organizing framework for the interplay of competition and cooperation.
Under the radar: How firms manage competitive uncertainty by appointing friends of other chief executive officers to their boards
Authors: Westphal James D. , Zhu David H.
Published: October 2018

Research Summary

In this study, we reveal a previously unstudied type of board tie that may help firms manage competitive uncertainty. While firms face regulatory barriers to the use of board interlock ties as a strategy for reducing competition, we suggest that firms can circumvent these barriers by appointing the friends of competitors' chief executive officers (CEOs) to their boards. Our theoretical framework addresses the antecedents, maintenance, and performance consequences of such “board‐friendship ties” to rivals. Our theory explains (a) why firms form and maintain board‐friendship ties, where maintenance involves the reconstitution of broken ties and (b) how firms form and maintain these ties, by revealing the role of search firms in identifying the friends of rivals' CEOs. Empirical analyses of large‐sample, longitudinal survey and archival data provide substantial support for our theory.

Managerial Summary

Firms can and do reduce competition and increase performance by appointing the friends of competitors' CEOs to their boards, and search firms (headhunters) play a key role in forming and maintaining these “board‐friendship” ties to competitors. While board interlock ties between close competitors are illegal and direct friendship ties between CEOs of competitors are relatively rare, board‐friendship ties are common, and yet largely unknown to antitrust regulators and external stakeholders.
Predicting probabilistic distribution functions of response parameters using the endurance time method
Authors: Mashayekhi Mohammad Reza , Mirfarhadi Seyed Ali , Estekanchi Homayoon E. , Vafai Hassan
Published: October 2018

The main objective of this study is the development of endurance time (ET) excitations in order to take structural response uncertainty into account for use in performance‐based earthquake engineering. There are several uncertainties in earthquake engineering, including earthquake occurrence, structural response, damage, and loss. In the current research, structural response uncertainty is directly included in the ET method, which is an analysis method used for performing structural behavior assessment under seismic actions. Conventional practice of the ET method does not provide any information about seismic response distribution. Despite the simplicity of the ET method, it is an accurate dynamic analysis approach in which structures are subjected to predesigned intensifying acceleration functions, also known as ET excitation functions (ETEFs). In this study, the ETEF generating procedure is modified in order to include the exceedance probability of structural responses observed at an intensity measure. This proposed method is applied to generate new ETEFs; then they are utilized in assessing distribution responses in three structure case studies. Finally, response distributions obtained by the ET method are compared with incremental dynamic analysis so as to investigate the proposed method efficiency. Results show that response probabilistic distributions that are predicted using the ET method match those obtained by incremental dynamic analysis.
Individual and collective agencies in China's curriculum reform: A case of physics teachers
Authors: Fu Guopeng , Clarke Anthony
Published: October 2018

This study explores how physics teachers in a high school negotiate the relationships between individual and collective agencies in the context of the on‐going curriculum reform in China. Drawing on Bandura's social cognitive theory, the study employs ethnographical methods including observation, interviewing, and the researcher's and teachers’ reflective journaling through the researcher's involvement with various school activities. The findings indicate that collective teacher agency creates a platform for individual teachers’ professional development, a conducive culture for teacher collaboration, and provides concrete examples that individual teachers can constantly refer to, reflect upon, and learn from for reform implementation. The results offer an understanding of the influences underlying physics teachers’ agency deployment as they engage with curriculum reform processes, especially the negotiation between individual and collective agencies. The findings justify a case for preparing physics teachers on how to deploy both individual and collective agencies in the face of the complicated social structures and ultimately shed light on the desired curriculum decentralization in the Chinese school system.
Saturation characteristics of a transformer under DC bias and their influence on the distribution of DC current in an AC power grid
Authors: Hanli Weng , Haowei Li , Zhenxing Li , Jingguang Huang , Xiangning Lin , Lei Liu , Sheng Wang
Published: October 2018

Based on the phenomenon of direct current (DC) component occurring in transformer magnetizing current in the case of transformer saturation resulting from DC bias, the influence of such a DC component on the distribution of DC current in the transformer neutral point is analyzed. By virtue of PSCAD/EMTDC software, the simulation model of a transformer suffering due to DC bias is built up to analyze the DC current characteristics in the transformer neutral point in the cases of taking into account and taking not into account of the transformer saturation caused by DC bias, respectively. According to the results obtained, the simulation value of DC current in the Yichang‐region power grid taking no account of transformer saturation is corrected. It is verified that the saturation of transformer magnetizing branch contributes to increase the DC current in the transformer neutral point. Taking into account the transformer saturation influence, the prediction accuracy of the DC current distribution in the AC power grid can be improved. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Many-body chaos and energy dynamics in holography
Authors: Blake Mike , Davison Richard A. , Grozdanov Sašo , Liu Hong
Published: October 2018

Abstract

Recent developments have indicated that in addition to out-of-time ordered correlation functions (OTOCs), quantum chaos also has a sharp manifestation in the thermal energy density two-point functions, at least for maximally chaotic systems. The manifestation, referred to as pole-skipping, concerns the analytic behaviour of energy density two-point functions around a special point ω = iλ, k = iλ/v

B
in the complex frequency and momentum plane. Here λ and v

B
are the Lyapunov exponent and butterfly velocity characterising quantum chaos. In this paper we provide an argument that the phenomenon of pole-skipping is universal for general finite temperature systems dual to Einstein gravity coupled to matter. In doing so we uncover a surprising universal feature of the linearised Einstein equations around a static black hole geometry. We also study analytically a holographic axion model where all of the features of our general argument as well as the pole-skipping phenomenon can be verified in detail.
Evaluation of expressive writing for postpartum health: a randomised controlled trial
Authors: Ayers Susan , Crawley Rosalind , Button Susan , Thornton Alexandra , Field Andy P. , Flood Chris , Lee Suzanne , Eagle Andrew , Bradley Robert , Moore Donna , Gyte Gill , Smith Helen
Published: October 2018

Pregnancy, birth and adjusting to a new baby is a potentially stressful time that can negatively affect the health of women. There is some evidence that expressive writing can have positive effects on psychological and physical health, particularly during stressful periods. The current study aimed to evaluate whether expressive writing would improve women’s postpartum health. A randomized controlled trial was conducted with three conditions: expressive writing (n = 188), a control writing task (n = 213), or normal care (n = 163). Measures of psychological health, physical health and quality of life were measured at baseline (6–12 weeks postpartum), 1 and 6 months later. Ratings of stress were taken before and after the expressive writing task. Intent-to-treat analyses showed no significant differences between women in the expressive writing, control writing and normal care groups on measures of physical health, anxiety, depression, mood or quality of life at 1 and 6 months. Uptake and adherence to the writing tasks was low. However, women in the expressive writing group rated their stress as significantly reduced after completing the task. Cost analysis suggest women who did expressive writing had the lowest costs in terms of healthcare service use and lowest cost per unit of improvement in quality of life. Results suggest expressive writing is not effective as a universal intervention for all women 6–12 weeks postpartum. Future research should examine expressive writing as a targeted intervention for women in high-risk groups, such as those with mild or moderate depression, and further examine cost-effectiveness.

Clinical trial registration number ISRCTN58399513 www.isrctn.com
Beyond Formal Access: Organizational Context, Working From Home, and Work–Family Conflict of Men and Women in European Workplaces
Authors: van der Lippe Tanja , Lippényi Zoltán
Published: October 2018

Working from home has become engraved in modern working life. Although advocated as a solution to combine work with family life, surprisingly little empirical evidence supports that it decreases work–family conflict. In this paper we examine the role of a supportive organizational context in making working from home facilitate the combination of work and family. Specifically, we address to what extent perceptions of managerial support, ideal worker culture, as well as the number of colleagues working from home influence how working from home relates to work–family conflict. By providing insight in the role of the organizational context, we move beyond existing research in its individualistic focus on the experience of the work–family interface. We explicitly address gender differences since women experience more work–family conflict than men. We use a unique, multilevel organizational survey, the European Sustainable Workforce Survey conducted in 259 organizations, 869 teams and 11,011 employees in nine countries (Bulgaria, Finland, Germany, Hungary, Netherlands, Portugal, Spain, Sweden, United Kingdom). Results show that an ideal worker culture amplifies the increase in work family conflict due to working from home, but equally for men and women. On the other hand, women are more sensitive to the proportion of colleagues working from home, and the more colleagues are working from home the less conflict they experience.
Revisiting gender differences in ultimatum bargaining: experimental evidence from the US and China
Authors: Li Shuwen , Qin Xiangdong , Houser Daniel
Published: October 2018

We report results from a replication of Solnick (Econ Inq 39(2):189, 2001), which finds using an ultimatum game that, in relation to males, more is demanded from female proposers and less is offered to female responders. We conduct Solnick’s (2001) game using participants from a large US university and a large Chinese university. We find little evidence of gender differences across proposer and responder decisions in both locations.
Common operation, uncommon complication. Bleeding from superior haemorrhoidal artery after minimally invasive procedure for hemorrhoids – a case report
Authors: Rajkumar Janavikula Sankaran , Reddy Aluru Jayakrishna , Radhakrishnan Ravikumar , Rajkumar Anirudh , Akbar Syed , Kollapalayam Raman Dharmendra
Published: October 2018

Minimally invasive procedure for hemorrhoids is one of the commonest new wave operations done for prolapsed hemorrhoids. The diameter of the stapled tissue is critical in this operation, and an increase in the same could include more tissue in the anvil, with disastrous results. This is a case report of a post minimally invasive procedure for hemorrhoids bleed, which was refractory to two local oversewing attempts. When the bleeding was massive, an angiogram was obtained. This revealed a pseudo aneurysm of the left superior haemorrhoidal artery, which was embolized, stopping the bleed. The stapler dimensions were studied and the possible cause of the event was arrived at. The specific stapler used had a diameter of 2 mm more than the regular Medtronic and Ethicon staplers, possibly including more of the rectal wall, and the superior haemorrhoidal artery as well. This case report documents a rare and potentially fatal complication of a simple procedure.
Fluid Handling Industry Update: M&A Activity
Authors: Haan Thomas E
Published: October 2018

The 2018 fluid handling industry deal activity started at a near record pace with 26 transactions in Q1 but slowed significantly in Q2 with only ten announced transactions, which is the second lowest level of deal activity in the last four years. So far (through August), Q3 deal volume appears to be on pace or slightly ahead of Q3 2017. This pattern is consistent with reports of general M&A activity year to date but seems inconsistent with the high level of interest that both strategic and private equity buyers continue to show in pursuing quality acquisitions in the fluid handling space.
The effect of an infographic promotion on research dissemination and readership: A randomized controlled trial
Authors: Huang Simon , Martin Lynsey J. , Yeh Calvin H. , Chin Alvin , Murray Heather , Sanderson William B. , Mohindra Rohit , Chan Teresa M. , Thoma Brent
Published: October 2018

CLINICIAN’S CAPSULE

What is known about the topic?

Infographics are graphical illustrations of complex ideas that are broadly shared on social media platforms.

What did this study ask?

What is the effect of a social media strategy using infographics on the readership and dissemination of research articles?

What did this study find?

Infographic articles were associated with increased Altmetric scores and abstract views, but not full-text views.

Why does this study matter to clinicians?

The promotion of articles with infographics may increase awareness and dissemination of research findings among clinicians.
Cerebrovascular Injury Following Scorpion Sting and Snake Envenomation: A Case Series
Authors: Mishra Ajay , Binu Aditya , Abraham George , Vanjare Harshad , George Tina , Iyadurai Ramya
Published: October 2018

Background

Neurological complications following snake and scorpion bite are diverse. Literature regarding patterns of cerebrovascular injury (CVI) and outcomes among these patients is scarce. This is a descriptive study of the clinical profile, brain imaging findings, mechanisms of injury, vascular territory involvement and outcomes of CVI following scorpion and snake envenomation, in a tertiary care center in South India.

Methodology

Patients with scorpion sting- and snake envenomation-related complications were retrospectively enrolled. Neuroimaging was performed on five patients with each envenomation, and they were found to have neurological involvement. On imaging, three patients were found to have a CVI. Clinical, radiological parameters and outcomes of these patients were studied. We also performed a review of the literature and analyzed the finding of all the cases.

Result

In all, three patients each had evidence of CVI in imaging. An additional 32 reports of scorpion sting-related CVI and 35 reports of snake envenomation-related CVI were identified from the literature. There was a male predominance among these patients. Mean age of the patients with scorpion sting was 42.8 years as compared with 33 years for the patients with snake envenomation. Features of severe envenomation were present in all patients. Persistently depressed sensorium and new-onset focal neurological deficits were seen in 70% of all patients. Infarcts were seen in 88% of patients with snake envenomation and 53% of patients with a scorpion sting. Mortality was 28% among patients with a scorpion sting as compared with 8% with snake envenomation.

Conclusion

Cerebrovascular injuries are uncommon neurological manifestations following scorpion and snake envenomation. These tend to occur in younger patients. Infarcts are more common than bleeds.
Asymmetric Information, Debt Capacity, and Capital Structure
Authors: Lemmon Michael L. , Zender Jaime F.
Published: October 2018

Capital structure choice based on costs associated with asymmetric information is examined in order to present a new perspective on the standard pecking order and trade-off theories. In the model, both the face value of debt and the restrictiveness of the associated debt covenants are chosen as part of the financial structure, allowing a more complete characterization of this decision. Debt structure choice balances ex ante adverse selection against ex post moral hazard, providing a natural integration of the pecking order and trade-off theories and the development of interesting empirical implications.
An investigation of the determinants of dialogue navigation in joint activities
Authors: KNUTSEN DOMINIQUE , COL GILLES , LE BIGOT LUDOVIC
Published: October 2018

When people engage in joint activities together, they use dialogue, and more specifically project markers such asyeah,okay, oruh-huh, to coordinate entrances and exits of projects and subprojects. The purpose of the current study was to examine how two features of the dialogue situation, namely, mental load and face visibility, affect project marker production. Pairs of participants performed a collaborative puzzle game together. Mental load was manipulated through time pressure; visibility was manipulated by allowing the participants to see each other’s face during the task, or not. Dialogues were transcribed and coded for project marker production. Project marker production was found toincreaseunder mental load; this also depended on the role of the speaker in the dyad (Director or Matcher) and on face visibility. This sheds light on the idea that dialogue partners may behavemorecollaboratively when experiencing high levels of mental load, contributing to a better understanding of mental resource allocation in dialogue-based joint activities.
‘Add info and stir’: an institutional ethnographic scoping review of family care-givers’ information work
Authors: Dalmer Nicole K.
Published: October 2018

Family care-givers are increasingly expected to find, understand and use information to meet the complex needs of older adults in their care. A significant number of studies, however, continue to report that care-givers’ information needs are unmet. Following Arksey and O'Malley's scoping review framework, I examined 72 articles for the range and extent of available research on the information work done by family care-givers of community-dwelling older adults living with dementia. To untangle the complex relationship between information and care, this scoping review maps out (a) the ways scholarly literature conceptualises the informational components of family care-givers’ work and (b) the degree to which scholarly research acknowledges these components as work. An institutional ethnography inflection enhanced the scoping review framework, enabling the privileging of lived experiences, questioning of assumptions of language used, attending to authors’ positioning and highlighting care-givers’ information work made invisible throughout the processes of academic research.
Creativity and meaning: including meaning as a component of creative solutions
Authors: Sääksjärvi Maria , Gonçalves Milene
Published: October 2018

The goal of this paper is to examine meaning as a component of creativity. We take a demand-based approach for conceptualizing meaning, and propose that it emerges from user needs instead of emerging from already existing creative solutions. Meaning is proposed as a third component of creativity, alongside novelty and usefulness. We test this proposition in a pre-study, and two empirical studies. In the pre-study, designers define creativity and provide examples of solutions that they deem creative. The results of the pre-study yield a 24-item scale for assessing creativity. Then, we conduct two empirical studies, in which we utilize the created scale for measuring creativity, and for examining the components arising thereof. In the first study, we ask creators (design engineering students) to generate ideas for one of two design briefs. Afterwards, creators were asked to rate their own creations, on the 24-item creativity scale. Here, we find a four-factor solution for creative outcomes, consisting of the dimensions novelty, usefulness, cleverness, and meaning. In the second study, we ask independent evaluators (individuals with related and relevant degrees) to assess the creators’ work on the creativity scale. Here, we find a three-factor solution for creative outcomes, consisting of the dimensions novelty, usefulness, and meaning. In both studies, meaning emerged as a separate component of creativity. Additionally, in both studies, it accounted for variance that was unaccounted for by novelty and usefulness, thereby increasing the overall explanatory power of creative solutions. These findings strongly speak of meaning as a third component of creativity.
Evidence of problem exploration in creative designs
Authors: Studer Jaryn A. , Daly Shanna R. , McKilligan Seda , Seifert Colleen M.
Published: October 2018

Design problems are often presented as structured briefs with detailed constraints and requirements, suggesting a fixed definition. However, past studies have identified the importance of exploring design problems for creative design outcomes. Previous protocol studies of designers has shown that problems can “co-evolve” with the development of solutions during the design process. But to date, little evidence has been provided abouthowdesigners systematically explore presented problems to create better solutions. In this study, we conducted a qualitative analysis of 252 design problems collected from publically available sources, including award-winning product designs and open-source design competitions. This database offers an independent sample of presented problems, designers’ alternative problem descriptions, and innovative solutions. We report the results of this large-scale qualitative analysis aimed at characterizing changes to problems during the design process. Inductive coding was used to identify content patterns in “discovered” problem descriptions, with qualitative codes reliably scored by two independent coders. A total of 32 distinct patterns of problem exploration were identified across designers and presented problems. Each pattern is described in the form of a generalized strategy to guide designers as they explore problem spaces. The exploration patterns identified in this study are the first empirical evidence of problem exploration in independent design problems. Further, the presence of exploration patterns in discovered problems is associated with the selection of the corresponding solution as a challenge finalist. These empirically identified strategies for problem exploration may be useful for computational tools supporting designers.
A systematic approach to assessing novelty, requirement satisfaction, and creativity
Authors: Ranjan B.S.C. , Siddharth L. , Chakrabarti Amaresh
Published: October 2018

It is well-known that creativity is crucial for sustaining a product against competition. Many factors have been proposed in the literature as indicators of creativity, among which outcome-characteristics-based factors are considered the most reliable; among these, the creativity of an outcome is often indicated by two major factors:noveltyandusefulness. Only a few studies address as to how creativity assessment methods and their results can be used during the design process. To systematically address the issue of how to influence creativity of design solutions, the following questions have been framed. (1) Which factors should be used as indicators of creativityconsistentlyacross different phases of the engineering design process? (2) How can creativity be assessed in terms of these factors during the engineering design process? In this work, we considernoveltyandusefulnessas the necessary factors forcreativity. It is found, however, that it is not possible todirectlyassess theusefulnessof outcomes during the design process. Therefore,requirement satisfactionis used as a proxy forusefulness. We propose a creativity assessment method that usesnoveltyandrequirement satisfactionas indicators for creativity; the method can be used for assessing not only complete products but also ideas or concepts, as they evolve through the phases of the design process. The application of the method in design is explained using a detailed example from a case study.
Life history traits of rare Antarctic dragonfishes from the Weddell Sea
Authors: La Mesa Mario , Riginella Emilio , Donato Fortunata , Mazzoldi Carlotta
Published: October 2018

The life history traits of bathydraconids, deep-living fishes distributed all around the Antarctic continent, are poorly known. In particular, very few data are available on the relatively rare generaAkarotaxisandBathydraco. With the aim to fill this gap, sagittal otoliths and gonads were analysed to assess individual age and reproductive features ofAkarotaxis nudiceps(Waite, 1916),Bathydraco macrolepisBoulenger 1907 andBathydraco marriNorman, 1938 collected in the Weddell Sea. Based on the annual growth increment patterns, age estimates ranged between 6–11, 5–11 and 8–11 years forA. nudiceps,B. macrolepisandB. marri, respectively. Most of the gametogenetic processes could be described based on gonad histology for both sexes. Females shared the reproductive features commonly reported in notothenioids, such as group-synchronous ovary development and prolonged gametogenesis. Total fecundity estimates were comparable between the two species ofBathydraco(1500–2500 eggs/female), whereas that ofAkarotaxiswas one order of magnitude smaller (200–250 eggs/female). Consistently, the mean size of late vitellogenic oocytes showed an opposite trend, being 1.6–1.8 mm inBathydracoand 2.2 mm inAkarotaxis.
Effect of adding heterologous versus homologous bovine seminal plasma prior to cryopreservation on bull sperm quality after thawing
Authors: Nongbua Thanapol , Al-Essawe Essraa M , Edman Anders , Johannisson Anders , Morrell Jane M
Published: October 2018

The aim of this study was to investigate the effect of adding homologous or heterologous bovine seminal plasma (SP) to SP-free sperm samples before freezing on sperm quality after thawing. Ejaculates from bulls of known fertility were used as a source of SP. The SP was removed from further aliquots of the same ejaculates by colloid centrifugation to create SP-free sperm samples; the resuspended sperm pellets were treated with homologous or heterologous SP from high or low fertility bulls at 0%, 1% or 5% before freezing. After thawing, sperm quality was evaluated by computer-assisted sperm analysis and flow cytometry for membrane integrity, reactive oxygen species, chromatin structure, mitochondrial membrane potential and protein tyrosine phosphorylation. Data were analysed using Proc MIXED, SAS®. Post-hoc comparisons were adjusted for multiplicity using Tukey’s method. The addition of SP resulted in significant differences in sperm quality, namely velocity class A, Velocity Straight Line (VSL), Velocity Average Path (VAP), Velocity Curved Line (VCL), Amplitude of Lateral Head Displacement (ALH), Hyperactive (HYP), reactive oxygen species (ROS) production and % DNA fragmentation index (DFI) (P<0.05 for each). Although adding 5% homologous SP from high fertility bulls was beneficial to sperm kinematics, 5% heterologous SP from high fertility bulls had a deleterious effect on chromatin integrity and on sperm velocity. In conclusion, adding SP may have either a beneficial effect or a deleterious effect depending on the individuals involved. It might be feasible to use this method to improve sperm quality in some circumstances.
Förderrelevante Diagnostik bei Lernstörungen
Authors: Lindberg Sven , Hasselhorn Marcus , Lonnemann Jan
Published: October 2018

Zusammenfassung. Eine umfangreiche Diagnostik ist zur Feststellung einer Lernstörung unumgänglich. Um eine Abweichung in schulischen Leistungen erfassen zu können, sind standardisierte und normierte Testverfahren notwendig, durch die eine individuelle Leistung mit einer altersbezogenen Normgruppe verglichen werden kann. Testverfahren im Bereich der Störungsdiagnostik müssen daher die kern-curricularen Inhalte der jeweiligen Klassenstufen abdecken. Förderrelevante Diagnostik zielt darüber auf die Erfassung spezifischer Basiskompetenzen und oder spezifischer Lernfortschritte ab und ermöglicht die Erstellung individueller Leistungsprofile und -verläufe. Dadurch können entsprechende Stärken und Schwächen ermittelt und die Grundlage für eine individuelle Förderung geschaffen werden. Im Bereich der technologiebezogenen Diagnostik besteht die aktuelle Herausforderung darin, angemessene Lösungen für die Erfassung förderrelevanter Informationen zu entwickeln.
Konzeption eines Online-Screenings für Lernstörungen
Authors: Richter Tobias , Lenhard Wolfgang , Marx Peter , Endlich Darius
Published: October 2018

Zusammenfassung. Der Beitrag skizziert ein Konzept für ein Online-Screening zur Diagnostik von Entwicklungsstörungen schulischer Fertigkeiten (Lernstörungen) im Grundschulbereich. Das Screening soll eine valide Identifikation von Kindern ermöglichen, die nur ein unterdurchschnittliches Fähigkeitsniveau in den Bereichen Lesen, Schreiben oder Rechnen erreichen, und zudem eine grobe Einschätzung der allgemeinen kognitiven Leistungsfähigkeit ermöglichen. Bei den identifizierten Risikokindern kann dann eine differenziertere und umfangreichere Diagnostik zur genaueren Abklärung der zugrunde liegenden Defizite und zur Ableitung von Förderempfehlungen erfolgen. Das Screening soll ökonomisch, d.h. in relativ kurzer Zeit und im Rahmen einer Gruppentestung, durchführbar sein.
Characteristics of Subpacket Structures in Ground EMIC Wave Observations
Authors: Kakad Bharati , Omura Yoshiharu , Kakad Amar , Upadhyay Aditi , Sinha Ashwini K.
Published: October 2018

Recent studies using satellite observations have reported that subpacket structures play an important role in determining the characteristics of electromagnetic ion cyclotron (EMIC) rising/falling tone emissions. The purpose of the present study is to investigate the subpacket structure characteristics in the ground observations of the EMIC waves. It will help us understand the effect of propagation on the EMIC subpacket structures. The induction coil magnetometer observations from Maitri, Antarctica (Geog. 70.77°S, 11.75°E, Geomag. 63.11°S, 53.59°E, L = 5), are used. Six quiet time EMIC events during 2015–2016 are analyzed and their details are presented. Based on their frequency extent in the power spectrum, four (two) events are speculated to be linked with proton (helium) band EMIC waves. For these events, the EMIC rising tone occurrence periods are estimated to be 1.9–6.7 min. Our analysis suggests that the amplitude‐frequency dependence of EMIC subpacket structures is less significantly affected during their prorogation to the ground. Overall, it is found that more than 70% of the time the EMIC waves are right‐handed elliptical polarized. An interesting feature is that the duration of the subpacket structure is found to be directly proportional to the EMIC wave amplitude. The observed characteristics and tendencies followed by EMIC subpacket structures on the ground are examined in the light of existing nonlinear wave theory and they are in good agreement. The EMIC wave amplitudes on the ground are found to be 16–80 times lower than the expected theoretical estimates of the wave amplitudes in the source region.
Generation of EMIC Waves Observed by Van Allen Probes at Low L Shells
Authors: Gamayunov Konstantin V. , Min Kyungguk , Saikin Anthony A. , Rassoul Hamid
Published: October 2018

Observation of linearly polarized He+‐band electromagnetic ion cyclotron (EMIC) waves at low L shells is a new, and quite unexpected, result from the Van Allen Probes mission. Here we analyze the two EMIC wave events observed by Van Allen Probes at low L shells and put forward a new‐generation mechanism for the low‐L EMIC waves. Both events were observed at L ∼ 3 but one of them has a discrete spectrum near the O+ gyrofrequency and its second harmonic, whereas the second event has a broad spectrum between the O+ gyrofrequency and its second harmonic. For both events, the major conclusions of our analysis can be summarized as follows. (1) Only O+ causes EMIC wave generation, and instability is driven by the positive derivatives of distribution functions over perpendicular component of velocity. (2) The timing and frequencies of generated waves are in agreement with observations. The generated wave normal angles, however, are highly oblique being in strong disagreement with the minimum variance angles obtained from Fast Fourier transform. (3) The wave step analysis shows that a signal nonstationarity is not a major cause for disagreement between the minimum variance angles and theoretical predictions for normal angles. (4) A superposition of plane sine waves with the same frequency and normal angle but with different azimuthal angles for wave vector around the background magnetic field can reconcile the polarization properties of EMIC waves obtained from Fast Fourier transform and/or the wave step analysis with those predicted by the linear theory of EMIC waves.
Mesospheric Temperature Inversions Observed in OH and O2 Rotational Temperatures From Mount Abu (24.6°N, 72.8°E), India
Authors: Singh Ravindra P. , Pallamraju Duggirala
Published: October 2018

We present a detailed investigation of upper mesospheric temperature inversions (MTIs) based on around 4.5 years of data of O2 and OH nightglow emission intensities (I(O2) and I (OH)) and temperature (T(O2) and T (OH)) corresponding to 94 and 87‐km altitudes. These measurements were carried out using Near‐Infrared Imaging Spectrograph from a low‐latitude location, Mount Abu (24.6°N, 72.8°E), in India. A total of 745 nights of Near‐Infrared Imaging Spectrograph observations is used, which showed the mean of T(O2) and T (OH) to be 199.6 and 203.0 K. However, there are nights that showed T(O2) greater than T (OH), which is considered as an indicator of upper MTIs. Among these nights, around 28% (209 out of 745) showed MTIs. It is found that 75% and 25% of MTIs occurred during premidnight and postmidnight hours. It was noted that maximum number of nights showed MTIs for a duration of around 4 hr followed by 3, 2, 5, and 6 hr. Investigation of causative mechanism for the upper MTIs revealed that although both wave dynamics and chemical heating by the exothermic reactions do work together, the in situ chemical heating process seems to be a more probable cause as compared to the vertical transport of energy from lower below. So far, such detailed statistics on MTIs does not exist in the published literature, and thus, the information presented in this work provides the necessary input for a greater understanding of the atmospheric temperature structure through modeling and simulation studies.
Response of Earth's Neutral Sheet to Reversals in the IMF By Component
Authors: Case N. A. , Grocott A. , Haaland S. , Martin C. J. , Nagai T.
Published: October 2018

The By component of the interplanetary magnetic field (IMF) plays an integral part in the coupling of the solar wind‐magnetosphere‐ionosphere system. In this study, we use a suite of magnetospheric spacecraft, with data spanning nearly 25 years, to statistically investigate the control of the IMF By component on the neutral sheet. Past studies have identified that this thin layer of the magnetotail, which separates the oppositely directed magnetotail lobes, responds to reversals in the IMF By component. The proposed method for driving this response is through unequal flux loading in the magnetotail lobes, and we present lobe flow data from the Cluster mission, which suggests that this is indeed the case. We find that the neutral sheet responds in a statistical fashion, with a clear twist or rotation whose orientation depends upon the polarity of the IMF By component. Additionally, under individual analyses, we find the response time of the neutral sheet to IMF By reversals is much shorter than possible through the classical dayside reconnection driven picture. We find an average response time of between 10 and 20 min with little to no dependence on distance downtail. These results suggest that the neutral sheet responds to the IMF By component on multiple timescales.
Statistical Planetary Period Oscillation Signatures in Saturn's UV Auroral Intensity
Authors: Bader A. , Badman S. V. , Kinrade J. , Cowley S. W. H. , Provan G. , Pryor W. R.
Published: October 2018

Saturn's auroral emissions are a good measure of field‐aligned current (FAC) systems in the planet's magnetospheric environment. Previous studies based on magnetic field data have identified current systems rotating with the planetary period oscillations (PPOs) in both hemispheres, superimposed onto the local time‐invariant current system producing the main auroral emission. In this study we analyze the statistical behavior of Saturn's ultraviolet auroral emissions over the full Cassini mission using all suitable Cassini‐UVIS images acquired between 2007 and 2017. We examine auroral intensities by organizing the data by the two PPO coordinate systems. Strong statistical intensifications are observed close to the expected locations of upward FACs in both hemispheres, clearly supporting the main assumptions of the present theoretical model. We furthermore find clear signatures of modulation due to interhemispheric current closure from the PPO system in the opposite hemisphere, although with a weaker modulation amplitude. The auroral intensity in the northern hemisphere is shown to be modulated by a superposition of the FACs associated with both PPO systems, as the modulation phase and amplitude varies as expected for different relative orientations (beat phases) of the two PPO systems.
A Model‐Based Analysis of Physical and Biogeochemical Controls on Carbon Exchange in the Upper Water Column, Sea Ice, and Atmosphere in a Seasonally Ice‐Covered Arctic Strait
Authors: Mortenson Eric , Steiner N. , Monahan A. H. , Miller L. A. , Geilfus N.‐X. , Brown K.
Published: October 2018

In this study, we consider a 1‐D model incorporating both sea ice and pelagic systems in order to assess the importance of various processes on the vertical transport and exchange of carbon in the seasonally ice‐covered marine Arctic. The model includes a coupled ice‐ocean ecosystem, a parameterization of ikaite precipitation and dissolution, a formulation for ice‐air carbon exchange, and a formulation for brine rejection and freshwater dilution of dissolved inorganic carbon (DIC) and total alkalinity (TA) associated with ice growth and melt. Sensitivity analyses illustrate that (1) the pelagic ecosystem accounts for more than half of the net ocean carbon uptake, but ice algae have little effect on the air‐sea exchange in the standard run; (2) inclusion of ikaite precipitation and dissolution do not strongly affect the net ocean carbon uptake for concentrations within the observed range but can become important for larger concentrations; (3) varying DIC and TA in the ice by equal amounts, or varying brine deposition depth, does not affect the net ocean carbon uptake, because the coincident changes in TA and DIC concentrations at the sea surface serve to counteract one another with respect to sea surface pCO2; and (4) the proportions of carbon released to the water column (versus to the atmosphere) during ice growth and melt are important quantities to constrain in order to determine the contribution of the combined ice‐ocean system to oceanic uptake of atmospheric carbon.