bluuebunny/crossref_metadata_2025_split huggingface dataset:
One‐step formation of polyurea gel as a multifunctional approach for biological and environmental applications
Authors: Bonattini Vinicius H , Paula Lucas AL , de Jesus Natana AM , Tavares Denise C , Nicolella Heloiza D , Magalhães Lizandra G , Molina Eduardo F 
Published: January 2020

AbstractThis work presents a facile one‐pot fabrication of polyurea (PU) organogels based on polyetheramine (PEO, Jeffamine ED‐2003) and a crosslinker hexamethylene diisocyanate trimer (HDI) which were subsequently used as a drug carrier to incorporate a curcumin hydrophobic molecule in aqueous conditions and for removal of an anionic pollutant in water. PU can be obtained in different shapes with easy control of film thickness with high transparency, flexibility and homogeneous dispersion of curcumin in the matrix. Due to the hydrophilic nature of PEO a high swelling degree was demonstrated by the PU gel. The phase separated domains and the temperature's influence on the system's structural order/disorder were examined by small‐angle X‐ray scattering, showing a more PU ordered system (interface between hard and soft segments) after decreasing the temperature to −90 °C. The presence of curcumin in the structure of PU was confirmed by Fourier transform infrared, photoluminescence and release studies. A highly efficient removal of Congo red dye from aqueous solution using PU as adsorbent was observed. Moreover, the effect of unloaded and curcumin‐loaded PU gels was evaluated onSchistosoma mansoniadult worms. Detailedin vitrocell viability experiments showed the biocompatibility of loaded and unloaded PU gels. The easy processability of the multifunctional PU shows that it has promising applications as transdermal and soft tissue implantable delivery devices for a large number of poorly water‐soluble drugs and as an efficient adsorbent for removal of organic dyes; it can also be used in the future in dermatological treatments against malignant melanoma. © 2020 Society of Chemical Industry
Visual‐based autonomous field of view control of laparoscope with safety‐RCM constraints for semi‐autonomous surgery
Authors: Sun Yanwen , Pan Bo , Fu Yili , Niu Guojun 
Published: January 2020

AbstractPurposeThe surgeon is not timely in direct control of his field of view. Autonomous laparoscope control can provide appropriate surgical field of view and facilitate the intelligent level of surgical robot system.MethodsThis study explores an autonomous laparoscope control framework for semiautonomous surgery. We propose a novel concept that integrates two forms of Remote Center of Motion (RCM) constraint. We also propose a novel safety‐RCM model to cope with the collision condition. We modify the image Jacobian matrix to realize RCM constraint. The two models constitute a dual‐RCM constraint for robot laparoscope arm. We perform validation of the algorithm with two experiments.ResultsThe experimental results show that the RCM position error can be reduced with the dual‐RCM constraint. Owing to safety‐RCM model, autonomous surgical field of view control could still be realized in case of collision.ConclusionThe autonomous laparoscope control could be realized with safety‐RCM and dual‐RCM algorithms.
Combining optical and radar satellite image time series to map natural vegetation: savannas as an example
Authors: Lopes Mailys , Frison Pierre‐Louis , Durant Sarah M. , Schulte to Bühne Henrike , Ipavec Audrey , Lapeyre Vincent , Pettorelli Nathalie 
Published: January 2020

AbstractUp‐to‐date land cover maps are important for biodiversity monitoring as they are central to habitat and ecosystem distribution assessments. Satellite remote sensing is a key technology for generating these maps. Until recently, land cover mapping has been limited to static approaches, which have primarily led to the production of either global maps at coarse spatial resolutions or geographically restricted maps at high spatial resolutions. The recent availability of optical (Sentinel‐2) and radar (Sentinel‐1) satellite image time series (SITS) which provide access to high spatial and very high temporal resolutions, is a game changer, offering opportunities to map land cover using both temporal and spatial information. These data moreover open interesting perspectives for land cover mapping based on data combination approach. However, the usefulness of combining dense time series (more than 30 images per year) and data combination approaches to map natural vegetation has so far not been assessed. To address this gap, this contribution tests the idea that the combined consideration of optical and radar data combination and time series analyses can significantly improve natural vegetation mapping in the Pendjari National Park, a Sahelian savanna protected area in Benin. Results highlight that the combination of Sentinel‐1 and Sentinel‐2 SITS performs as well as Sentinel‐2 SITS alone in terms of classification accuracy. Land cover maps are however qualitatively better when considering the data combination approach. Our results also clearly show that the use of dense/hypertemporal optical time series significantly improves classification outcomes compared to using multitemporal only a few images per year) or monotemporal data. Altogether, this work thus demonstrates the ability of dense SITS to improve discrimination of natural vegetation types using information on their phenology, leading to more detailed and more reliable maps for environmental management.
Students' adherences to epistemic understanding in evaluating scientific claims
Authors: Leung Jessica Shuk Ching 
Published: January 2020

AbstractEpistemic understanding of science is essential for critical evaluation of scientific claims. In principle, developing students' epistemic understanding would enhance students' capability in evaluating scientific claims. However, findings on this “expected” connection have been inconclusive. This paper seeks to examine this discrepancy between epistemic understanding in theory, and the practical application of this understanding. It uses the concept of adherence from the literature on conceptual change when accounting for this discrepancy. Questionnaires were used to examine adherences to epistemic understanding in evaluating health‐related claims by 42 college‐level nonscience majors. Follow‐up interviews were conducted to explain their adherences to epistemic understanding during their evaluation. The analysis revealed that: (a) Students tended to adhere to process of inquiry much stronger than the nature of scientific knowledge and the social context of science. (b) Students' low adherence to the nature of scientific findings and generation process was found to relate to an interplay among various epistemic aspects of science. (c) Students demonstrated low adherence in practicing epistemic understanding due to difference in contexts between giving declarative statements about science and using epistemic understanding to evaluate scientific claims. These findings have theoretical implications on the discrepancy between theory and practice in relation to the role of epistemic understanding of science, and on what constitutes informed epistemic understanding. They also have practical implications in terms of enhancing students' adherences to epistemic understanding in evaluating scientific claims.
Critical science agency and power hierarchies: Restructuring power within groups to address injustice beyond them
Authors: Schenkel Kathleen , Calabrese Barton Angela 
Published: January 2020

AbstractPromoting critical science agency (CSA) may be one way to promote educational justice. CSA is using science with other powerful forms of knowledge to address issues of injustice. However, the process of enacting CSA is always embedded within a sociopolitical context, which positions some students with more power than others. Drawing upon a social practice theory analytical lens with a focus on power and using critical participatory ethnography methods, this study investigated the ways middle school students restructured power hierarchies as they worked to complete the design challenge of making their classroom community more sustainable, and how power hierarchy restructuring impacted students' opportunities to enact CSA. Findings show as the students enacted collective CSA, they were responding to unmet students' needs grounded in systems of power operating within their classroom. Throughout the engineering design process, students' understandings of their defined issue of injustice was both refined and critical to their technical and social design considerations. Finally, as the groups enacted CSA, power hierarchy disruptions, though incomplete, through the recognition of students' expertize and distributing roles, supported their efforts to address their class‐wide concerns. These findings highlight how restructuring power hierarchies supported youth enacting collective CSA, which then further supported them in reshaping their classroom community to be more justice‐oriented.
The (Un) intended consequences of institutions lowering barriers to entrepreneurship: The impact on female workers
Authors: Castellaneta Francesco , Conti Raffaele , Kacperczyk Aleksandra 
Published: January 2020

AbstractWe propose that institutions that reduce barriers to entrepreneurship lead to intended consequences, increasing entry rate among individuals facing obstacles to entrepreneurship, such as women. But these regulations also have unintended consequences, decreasing the value appropriated by women who stay in paid employment, as these women lose support of their departing peers. Using an exogenous reduction in entry barriers in Portugal between 2005 and 2009, we find that women launch new ventures at higher rates than men, when entry barriers fall, but the same changes lead to a relative decline in women's wages in paid employment. These effects are amplified for women in managerial positions, who benefit if they leave but lose if they stay. Our study contributes to a nuanced understanding of rent‐allocation in firms.Managerial SummaryWe study the unintended consequences of lowering barriers to entry—an important institutional change to foster entrepreneurship, especially among those facing strongest entry barriers. We examine the effects of such regulations on women departing to entrepreneurship and those staying in incumbent firms, using the registry data from Portugal. The results show that lowering entry barriers leads to higher rates of entrepreneurial entry among women, as intended. But we also find that this deregulation reform results in a wider gender pay gap among those who stay in incumbent firms. We attribute these increases to reductions in bargaining power and productivity, which result from the departure of socially‐proximate peers. Finally, these intended and unintended consequences are especially common among female managers—who are more likely to leave for entrepreneurship, on the one hand, but also more likely to witness greater pay gaps in wage work, on the other hand.
Serving differently: CEO regulatory focus and firm stakeholder strategy
Authors: Gamache Daniel L , Neville François , Bundy Jonathan , Short Cole E 
Published: January 2020

AbstractResearch summaryA fundamental question in stakeholder strategy research is why firms adopt certain strategies or approaches to engage with key stakeholders. Recent research suggests that CEOs' characteristics can influence their general decisions to engage with stakeholders, however, this work has yet to consider why CEOs might utilize specific stakeholder strategies. In this article, we demonstrate how CEO regulatory focus influences the nature of a firm's stakeholder strategy. Specifically, we argue that CEO prevention focus is positively associated with engagement in governance‐oriented initiatives and receptivity to governance‐oriented stakeholder activism, while CEO promotion focus is positively associated with engagement in socially‐oriented initiatives and receptivity to socially‐oriented stakeholder activism. We find strong support for our hypotheses in a sample of 374 publicly‐traded firms.Managerial summaryThe strategies a firm uses to engage with stakeholders can influence its performance, yet little is known about what makes firms focus on certain stakeholders over others. To better understand this, we examined CEO regulatory focus in a sample of large public companies. Our findings reveal that the way CEOs view decisions—either based on a sense of duty, obligations, and responsibility or as a means to achieve high ideals—influences their tendency to prioritize shareholder concerns or the concerns of a broader array of stakeholders. This suggests that executives should be aware of their own natural tendencies to inject their motivations into their firm's stakeholder strategy and consider avenues to balance their perspectives for the sake of the firm.
Mind the gap: The role of gender in entrepreneurial career choice and social influence by founders
Authors: Rocha Vera , van Praag Mirjam 
Published: January 2020

AbstractResearch summaryWomen continue to be disproportionately underrepresented in new venture creation. We investigate whether and how founders can differently influence future entrepreneurial career choices of their male and female joiners. Using a large sample of startup firms with personnel where founders interact closely with joiners, we demonstrate that founders have a strong influence on a joiner's entrepreneurial career choice if both are female. We find empirical support for role modeling as a key underlying mechanism, accounting for alternative explanations such as selective matching based on gender and push‐driven factors. These findings increase our understanding of the roles of socialization and organizational context in shaping the career outcomes of employees, and provide evidence of a multiplier effect of female entrepreneurs.Managerial summaryWomen are less likely to be entrepreneurs than men. We investigate whether working in a startup founded by a woman instead of a man influences individuals' decision to become an entrepreneur later. We find this to be the case for women. This result is best explained by female founders acting as role models for their female employees in male‐dominated domains. Female founders able to break gender stereotypes seem to have an influence on the career choices of their female employees, especially among those who have lacked contact with entrepreneurs. Moreover, this influence is stronger if the female founder and employee have similar backgrounds. These findings confirm the importance of social interactions at work and suggest new ways to inspire more women to launch startups.
Effects of Physiological Condition on Aspects of Repeat Spawning in Female Steelhead Reconditioned in Captivity
Authors: Jenkins Laura E. , Pierce Andrew L. , Caudill Christopher C. , Graham Neil D. , Medeiros Lea R. , Hatch Douglas R. , Nagler James J. 
Published: January 2020

AbstractPhysiological condition (hereafter shortened to “condition”) influences survival, spawning schedules, and reproductive effort in salmonids. In iteroparous females, the effects of first spawning on condition could result in trade‐offs with future reproduction, mediated by postspawning survival, repeat spawning schedule (i.e., consecutive or skip spawning), or reproductive effort. However, which aspects of condition affect these outcomes and when they are sensitive to condition are not well understood. These issues were examined in highly energy‐depleted hatchery‐origin female summer steelhead Oncorhynchus mykiss that were undergoing postspawning reconditioning in captivity. Measures of condition and reproductive characteristics (i.e., fecundity, egg size, and total egg mass [TEM]) at first spawning were examined for their effects on postspawning survival and future spawning schedules, and condition was tracked during reconditioning to examine effects on reproductive characteristics at repeat spawning. The levels of plasma osmolality and triglycerides measured at first spawning were positively correlated with survival probability, suggesting that survival depends on the ability to maintain homeostasis and access stored energy. Surprisingly, size‐standardized TEM measured at first spawning was positively correlated with the probability of consecutive spawning, providing no support for the hypothesized trade‐off between current and future reproduction. This finding instead suggests that both first‐spawning reproductive effort and consecutive spawning may be influenced by condition at earlier points. Plasma triglycerides and growth rates at sampling points 10–20 weeks after first spawning were strongly correlated with size‐standardized egg size and TEM at consecutive spawning, suggesting that reproductive effort and its allocation to egg size and fecundity depend on energetic status during early oogenesis. These results indicate that condition influences survival, repeat spawning schedules, and reproductive characteristics in female steelhead up to a year or more before repeat spawning. If more broadly applicable, these relationships could provide insight into the mechanisms that link environmental conditions with reproductive characteristics in salmonids and other species.
Maximum thermodynamic power coefficient of a wind turbine
Authors: Tavares J. M. , Patrício P. 
Published: January 2020

AbstractAccording to the centenary Betz‐Joukowsky law, the power extracted from a wind turbine in open flow cannot exceed 16/27 of the wind transported kinetic energy rate. This limit is usually interpreted as an absolute theoretical upper bound for the power coefficient of all wind turbines, but it was derived in the special case of incompressible fluids. Following the same steps of Betz classical derivation, we model the turbine as an actuator disk in a one dimensional fluid flow but consider the general case of a compressible reversible fluid, such as air. In doing so, we are obliged to use not only the laws of mechanics but also and explicitly the laws of thermodynamics. We show that the power coefficient depends on the inlet wind Mach number
, and that its maximum value exceeds the Betz‐Joukowsky limit. We have developed a series expansion for the maximum power coefficient in powers of the Mach number
that unifies all the cases (compressible and incompressible) in the same simple expression:
.
Generic invariant measures for iterated systems of interval homeomorphisms
Authors: Czernous Wojciech , Szarek Tomasz 
Published: January 2020

AbstractIt is well known that iterated function systems generated by orientation preserving homeomorphisms of the unit interval with positive Lyapunov exponents at its ends admit a unique invariant measure on (0, 1) provided their action is minimal. With the additional requirement of continuous differentiability of maps on a fixed neighbourhood of $$\{0,1\}$${0,1}, we present a metric in the space of such systems which renders it complete. Using then a classical argument (and an alternative uniqueness proof), we show that almost singular invariant measures are admitted by systems lying densely in the space. This allows us to construct a residual set of systems with unique singular stationary distribution. Dichotomy between singular and absolutely continuous unique measures is assured by taking a subspace of systems with absolutely continuous maps; the closure of this subspace is where the residual set is found.
Epigenetic histone modulation contributes to improvements in inflammatory bowel disease via EBI3
Authors: Wetzel Alexandra , Scholtka Bettina , Gerecke Christian , Kleuser Burkhard 
Published: January 2020

AbstractUlcerative colitis (UC) is characterized by relapsing–remitting inflammatory episodes paralleled by varying cytokine levels, suggesting that switching epigenetic processes might be involved. However, the epigenetic impact on cytokine levels in colitis is mostly unexplored. The heterodimeric interleukin (IL)-12 cytokine family have various functions in both pro- and anti-inflammatory processes. The family member IL-35 (EBI3/IL-12p35) was recently reported to play an anti-inflammatory role in UC. Therefore, we aimed to investigate a possible epigenetic regulation of the IL-35 subunits in vitro and in vivo, and to examine the epigenetic targeting of EBI3 expression as a therapeutic option for UC. Exposure to either the pro-inflammatory TNFα or to histone deacetylase inhibitors (HDACi) significantly increased EBI3 expression in Human Colon Epithelial Cells (HCEC) generated from healthy tissue. When applied in combination, a drastic upregulation of EBI3 expression occurred, suggesting a synergistic mechanism. Consequently, IL-35 was increased as well. In vivo, the intestines of HDACi-treated wild-type mice exhibited reduced pathological signs of colitis compared to non-treated colitic mice. However, the improvement by HDACi treatment was completely lost in Ebi3-deficient mice (Ebi3−/−). In fact, HDACi appeared to exacerbate the disease phenotype in Ebi3−/−. In conclusion, our results reveal that under inflammatory conditions, EBI3 is upregulated by the epigenetic mechanism of histone acetylation. The in vivo data show that the deficiency of EBI3 plays a key role in colitis manifestation. Concordantly, our data suggest that conditions promoting histone acetylation, such as upon HDACi application, improve colitis by a mechanism involving the local formation of the anti-inflammatory cytokine IL-35.
Reductions in body sway responses to a rhythmic support surface tilt perturbation can be caused by other mechanisms than prediction
Authors: Assländer Lorenz , Gruber Markus , Giboin Louis-Solal 
Published: January 2020

AbstractStudies investigating balance control often use external perturbations to probe the system. These perturbations can be administered as randomized, pseudo-randomized, or predictable sequences. As predictability of a given perturbation can affect balance performance, the way those perturbations are constructed may affect the results of the experiments. In the present study, we hypothesized that subjects are able to adapt to short, rhythmic support surface tilt stimuli, but not to long pseudo-random stimuli. 19 subjects were standing with eyes closed on a servo-controlled platform tilting about the ankle joint axis. Pre and post to the learning intervention, pseudo-random tilt sequences were applied. For the learning phase, a rhythmic and easy-to-memorize 8-s long sequence was applied 75 times, where subjects were instructed to stand as still as possible. Body kinematics were measured and whole body center of mass sway was analyzed. Results showed reduced sway and less forward lean of the body across the learning phase. The sway reductions were similar for stimulus and non-stimulus frequencies. Surprisingly, for the pseudo-random sequences, comparable changes were found from pre- to post-tests. In summary, results confirmed that considerable adaptations exist when exposing subjects to an 8-s long rhythmic perturbation. No indications of predictions of the learning tilt sequence were found, since similar changes were also observed in response to pseudo-random sequences. We conclude that changes in body sway responses following 75 repetitions of an 8-s long rhythmic tilt sequence are due to adaptations in the dynamics of the control mechanism (presumably stiffness).