bluuebunny/crossref_metadata_2025 huggingface dataset:
Reviewing the role of plant litter inputs to forested wetland ecosystems: leafing through the literature
Authors: Stoler Aaron B. , Relyea Rick A.
Published: December 2019

The input of senescent terrestrial leaf litter into soil and aquatic ecosystems is one of the most massive cyclic subsidies on Earth, particularly within forested ecosystems. For freshwater systems embedded within forests, litter inputs provide a vital source of energy and nutrients that allows greater production than in situ resources can provide. In return, freshwater food webs can provide an enormous amount of material to the terrestrial landscape through biotic respiration, photosynthesis, and organism emergence. Most research concerning this important aquatic‐terrestrial link has focused on lotic ecosystems (i.e., streams and rivers); far less attention has been given to its role in lentic systems (i.e., wetlands and lakes). A focus on small forested wetlands is particularly important, as these systems account for a disproportionate amount of global carbon flux relative to their spatial coverage, and the decomposition of leaf litter is a major contributor. Here, we review six themes: (1) the evidence for the role of leaf litter inputs as an ecologically important subsidy in forested wetlands; (2) the bottom‐up effects of quantitative and qualitative variation in litter inputs; (3) how diversity in litter mixtures can alter ecological functioning; (4) evidence for top‐down consequences of litter inputs through toxic effects on predators and parasites, and the alteration of predator–prey interactions; (5) the relevance of our review to other research fields by considering the role of litter inputs relative to other types of subsidies and environmental gradients (e.g., temperature, canopy cover, and hydrology); and (6) the interaction of litter subsidies with anthropogenic disturbances. We conclude by highlighting several high‐priority research questions and providing suggestions for future research on the role of litter subsidies in freshwater ecosystems.
Tactical departures and strategic arrivals: Divergent effects of climate and weather on caribou spring migrations
Authors: Gurarie Eliezer , Hebblewhite Mark , Joly Kyle , Kelly Allicia P. , Adamczewski Jan , Davidson Sarah C. , Davison Tracy , Gunn Anne , Suitor Michael J. , Fagan William F. , Boelman Natalie
Published: December 2019

The Arctic has been warming rapidly, affecting ecological processes across the region. Caribou and reindeer (Rangifer tarandus) is a keystone Arctic species undergoing declines in many parts of its range, but definitive links between climate and populations remain elusive. The conspicuous and dramatic mass migration of many caribou populations, during which nearly all pregnant females move from wintering ranges to calving grounds shortly before giving birth, may be an important link between climate and caribou populations. The drivers of migration, however, are similarly mysterious. It is unknown, for example, whether caribou respond to immediate phenological cues, anticipate conditions on calving grounds, or are driven by lagged effects related to physical condition. To investigate the drivers of migration, we analyzed movement data from over 1000 individual caribou from seven major herds, spanning 3000 km across Alaska, Yukon, Northwest Territories (NWT), and Nunavut in Canada, from 1995 to 2017. We developed a hierarchical model to estimate migration departure and arrival times, and analyzed these variables against global climate indices and local weather conditions, exploring immediate and lagged effects, as well as snowmelt timing and vegetation indices. We discovered a continent‐wide synchrony in spring migration departure times, driven mainly by large‐scale, ocean‐driven climate indices (Pacific Decadal Oscillation, Arctic Oscillation, and North Atlantic Oscillation). However, we also found that the speed of migration was highly plastic with later migration departure times followed by shorter migration durations. This plasticity made arrival timing independent of departure timing and its respective drivers. Rather, arrival timing depended strongly on weather conditions from the previous summer: cooler and windier summers generally led to earlier arrival at calving grounds the following year. We suggest that maternal body condition, mainly influenced by conditions that limit insect harassment, is a major factor for earlier spring migration arrival timing, and therefore earlier calving and higher survival rates. We place these results in the context of mechanistic links between climate and caribou population dynamics. Long‐term and large‐scale observations of migratory animals can provide insights into the mechanisms by which long‐distance, collective migrants may adapt to dynamic and unpredictable environments.
Timing to temperature: Egg‐laying dates respond to temperature and are under stronger selection at northern latitudes
Authors: Shave Amanda , Garroway Colin J. , Siegrist Joe , Fraser Kevin C.
Published: December 2019

Global climate change produces spatially variable patterns of environmental change. This could put migratory species at risk as the synchrony between migration timing and suitable breeding conditions could become mismatched. For migratory birds, whether the timing of egg laying is a plastic trait that can vary in response to environmental change has been sparsely studied across regions and systems and thus remains poorly known. We investigated the effects of temperature variability and climate warming on the breeding phenology of purple martins (Progne subis), a long‐distance migratory songbird, using a 20‐yr data set comprised of 28,165 records of nest timing and fledgling success spanning the entire breeding range (25–54° N). We discovered that purple martins lay eggs earlier in warmer springs and fledge more young when they lay earlier. After controlling for spatial patterns in the data with Moran's eigenvector maps, we found that selection favored earlier breeding in most years, particularly at more northern latitudes. However, selection pressure for earlier breeding did not increase over the 20‐yr period, perhaps owing to high variability in temperature across years. Our results therefore demonstrate plasticity in the timing of egg laying in response to temperature variation and climate change over 20 yr across the range of this widely distributed, long‐distance migrant. Whether these plastic responses are common or sufficiently matched to climate change among other declining migratory songbird species should be further investigated.
Nitrogen Fixation Catalyzed by Dinitrogen‐Bridged Dimolybdenum Complexes Bearing PCP‐ and PNP‐Type Pincer Ligands: A Shortcut Pathway Deduced from Free Energy Profiles
Authors: Egi Akihito , Tanaka Hiromasa , Konomi Asuka , Nishibayashi Yoshiaki , Yoshizawa Kazunari
Published: December 2019

Density‐functional‐theory (DFT) calculations are carried out for the proposal of a theoretically‐plausible reaction pathway for nitrogen fixation catalyzed by dinitrogen‐bridged dimolybdenum complexes bearing pincer‐type PCP and PNP ligands. The free energy profiles of the entire reaction pathway calculated with a dispersion‐corrected functional provide a catalytic mechanism energetically more efficient than the previously proposed one [Nat. Commun. 2014, 5, 3737]. In the newly‐proposed mechanism the dinuclear Mo–N≡N–Mo structure should be maintained during the catalytic cycle. Despite the coordination of the triflate group with a strong electron‐withdrawing ability, dinitrogen coordinated to a MoI center has higher reactivity with a proton donor than that coordinated to an electron‐rich Mo0 center. The calculated results enable us to propose a shortcut pathway in which the regeneration of the dimolybdenum Mo0Mo0 complex is not required. Intermetallic electron transfer between the two Mo centers induced by protonation effectively enhances the reactivity of coordinate N2 with a proton donor. Our calculations reveal that the synergy of the Mo centers at the protonation step is essential for the catalytic performance of the dimolybdenum system.
Stepwise Preparation of meso‐Tetraphenyl‐ and meso‐Tetrakis(4‐trifluoromethylphenyl)bacteriodilactones and their Zinc(II) and Palladium(II) Complexes
Authors: Brückner Christian , Atoyebi Adewole O. , Girouard Derek , Lau Kimberly S. F. , Akhigbe Joshua , Samankumara Lalith , Damunupola Dinusha , Khalil Gamal E. , Gouterman Martin , Krause Jeanette A. , Zeller Matthias
Published: December 2019

While the direct, one‐step conversion of meso‐tetrakis(pentafluorophenyl)porphyrin to its corresponding bacteriodilactone is well established, no such reaction has been achieved for meso‐tetraphenyl or meso‐tetrakis(4‐trifluoromethylphenyl)porphyrin. Thus, we describe two stepwise oxidation approaches of these porphyrins toward the corresponding bacteriodilactones, as mixtures of two inseparable regioisomers. As shown by 1H NMR spectroscopy, the ratio of the two isomers is oxidant‐dependent. Their ZnII and PdII complexes were formed by metal ion insertion into the free bases. Some of the free base dilactones and their metal complexes were also characterized crystallographically, demonstrating the planarity of the macrocycle. This report makes these intriguing porphyrinoids synthetically accessible for further study.
Innovative and efficient method of robotics for helping the Parkinson's disease patient using IoT in big data analytics
Authors: Sivaparthipan C.B. , Muthu Bala Anand , Manogaran Gunasekaran , Maram Balajee , Sundarasekar Revathi , Krishnamoorthy Sujatha , Hsu Ching‐Hsien , Chandran Karthik
Published: December 2019

Big data had accumulated a massive amount of stored data for applications including robotics, internet of things (IoT), and healthcare system. Although the IoT‐based healthcare system plays a vital role in big data industry, in some case, the sensing may be difficult to predict the accurate result. The proposed system with artificial intelligence and IoT for Parkinson's disease can enhance the gait performance tremendously. This research clearly defines the role of robots in Parkinson's disease and how they interact with big data analytics. To process the research scheme, data are collected from big data. Moreover, Laser scanned scheme with piecewise linear Gaussian dynamic time warp machine learning is introduced. In order to scan the path for obstacle and safe place, laser scan system is used. The main role of robot is to predict the walker motion and give physical training to the patient. To predict the walker motion of patient, robot has to walk along with patient since the sensors are fixed in both the patient and the robot. Finally, the performance of proposed methodology is evaluated with existing works.
Authentic Self in Evaluation Consulting: Reflections after 10 Years
Authors: Fierro Rita Sinorita
Published: December 2019

This chapter offers a process and a series of exercises for achieving the authenticity of a brand via authentic leadership based on an independent evaluation consultant's 10‐year evolution. This process weaves together four aspects: authentic self, authentic goals, authentic relationships, and authentic lifestyle. Each aspect is guided by an inquiry question: Who am I? What do I care most about? What work is mine to do in the world? What partnerships are consistent with who I am? What schedule provides the best work/life balance for me? Together, these inquiry questions generate a learning journey for the consultant or the firm that is iterative, from year to year. The learning journey includes: understanding personal preferences, learning one's positionality, investing in one's self‐development and soft skills, finding one's tribe, and learning who is one's ideal client. Over time, these practices of self‐reflection on past, present, and future work can build one's authenticity, creating a strong and sustainable brand, and strong and sustainable life for the firm's leaders and workers.
Growing and Nurturing Your Evaluation Business When Your Independent Consultancy Becomes an Employer
Authors: Moses Leah Goldstein
Published: December 2019

Lessons learned from 19 years building an evaluation consulting business can inform other business owners. The Improve Group has grown from a one‐woman consultancy to an employer of more than thirty people. Staying grounded in a mission and a clear set of values is a guiding principle that has guided and informed growth. Sharing power with staff—to operate democratically while also leveraging their great ideas—has also strengthened The Improve Group's evaluation practice and operations as an organization. Balancing short‐ and long‐term opportunities has helped the organization stay nimble and situate itself well for the future. Reflections on major organizational changes—including a team restructure and the addition of a more inclusive approach to evaluation—show the application of these guiding principles. Additional personal reflections on leadership shed light on what founder and CEO Leah Goldstein Moses has learned about her leadership style over nearly 20 years at the helm of The Improve Group.
Standing on the Shoulders of Giants: Applying Business Management Approaches to Independent Evaluation Consulting
Authors: Feldmann Matthew L.
Published: December 2019

Independent evaluation consultants frequently discuss “how‐to” strategies to determine ways to start or improve their practices. Mostly this involves sharing advice on a range of topics such as how and when to set up a corporate structure, what accounting software to use, how to develop new business, and where to work. Such advice also should include information about business theory that more broadly orients consultants to business planning. This movement, from the “how” to the “why,” is imperative for long‐term business success. This chapter introduces three widely accepted business books that cover niche identification, market focus, business development, smart business growth, and the importance of generosity with networking. The reader is oriented to these concepts through Amy, a fictitious, introverted independent evaluation consultant, and her new consulting practice, EduEval USA. Amy demonstrates how to identify appropriate goals and her niche market, develops a marketing approach that is appropriate for a service consultancy, and begins networking with other evaluators and educators in her community.
Branding for the Independent Consultant: Basic to Advanced
Authors: Evergreen Stephanie , Sabarre Nina
Published: December 2019

With a growing contingency of evaluators consulting in the gig economy, questions have shifted from “Should I?” to “How do I?” This chapter provides tips and strategies for branding your business as an independent consultant. Branding has become increasingly important for independent consultants, as a way to tell the world who you are and the unique value you offer. For new consultants, branding is a means for potential clients to find and remember you, and for you to showcase your skills and competencies. For established consultants or businesses, branding can be a catalyst to land bigger (as in, higher profile or larger) and better (as in, more lucrative, connected, or longer‐term) clients. This chapter delves into three hypothetical case studies of evaluation consultants, Jason, Siobhan, and Anuj, to provide insight into how branding, and different levels of branding, can help them attract the types of clients they desire. Examples of exemplar branding from established evaluation companies are also shared throughout the chapter.
Survey modes comparison in contingent valuation: Internet panels and mail surveys
Authors: Ryan Mandy , Mentzakis Emmanouil , Matheson Catriona , Bond Christine
Published: December 2019

Stated preferences methods are extensively applied in health economics to elicit preferences. Although mailed surveys were commonly used to collect data, internet panel (IP) surveys are being increasingly used. This raises questions about the validity of responses and estimated willingness‐to‐pay (WTP) values generated from IP surveys. We conduct the first study in health to compare a contingent valuation IP survey with a mailed survey using the electoral roll. Our IP has a higher response rate and lower item missing response rate. The difference is reduced but remains when restricting comparisons with valid WTPs. Sample characteristics differ, with significant differences between modes for gender, age, income, and attitudes and knowledge. Although difference in WTP values exist, with the IP resulting in higher values, we find limited evidence that such differences are statistically significant. The mail survey has lower initial cost per response; however, once restricting samples to valid WTP responses with nonmissing respondent information, the cost per response across modes is similar. Our results, suggesting that IPs generate valid and cost‐effective values, are encouraging as researchers move increasingly to IPs to collect preference data.
Does pre‐packed bankruptcy create value? An empirical study of postbankruptcy employment retention in The Netherlands
Authors: Aalbers Henrick , Adriaanse Jan , Boon Gert‐Jan , van der Rest Jean‐Pierre , Vriesendorp Reinout , Van Wersch Frank
Published: December 2019

In recent years, there has been growing interest in whether pre‐packed bankruptcy can be a mechanism through which firms facing imminent insolvency can preserve value. Although an extensive body of literature exists on “pre‐packs,” whether such techniques really preserve value remains ambiguous. By analysing bankruptcy proceedings filed with Dutch courts in the period 2012–2018 through the lenses of real options and debt overhang theory, we examined employment retention postbankruptcy as a consequence of the type of bankruptcy proceeding (pre‐packed bankruptcy and conventional bankruptcy) and the severity of prebankruptcy financial distress. The results show that in the Netherlands, a pre‐packed bankruptcy, when compared with a conventional bankruptcy proceeding, positively impacts employment retention rates after bankruptcy. The severity of financial distress before bankruptcy does not affect employment retention rates postbankruptcy. This implies that despite the amount of resource slack, the preservation of employee value is better served under a pre‐packed bankruptcy than a conventional bankruptcy proceeding. This finding is important for insolvency practice, as up to 22 June 2017, employee rights in the Netherlands (including redundancy) were not considered to be automatically transferred to the firm acquiring the bankrupt debtor's assets when a pre‐packed bankruptcy was applied. Implications for insolvency regulation and practice are discussed.
First‐Principles Calculations of Phonons and Thermodynamic Properties of Zr(Hf)S2‐Based Nanotubes
Authors: Domnin Anton V. , Bandura Andrei V. , Evarestov Robert A.
Published: December 2019

Comparative hybrid density functional calculations on the structure, stability, and phonon frequencies of monolayers and single‐walled nanotubes are performed for Zr(Hf)S2 disulfides. The first‐principles calculations of HfS2‐based nanotubes are made for the first time. The symmetry analysis of infrared and Raman active vibrational modes in ZrS2 and HfS2 nanotubes is made using the induced representations of the isogonal point groups of line groups. It is shown that the number of infrared and Raman active modes is constant for NTs with the same chirality type. The correlation of the phonon modes of the nanotubes of relatively large diameters with those of monolayer is analyzed. The thermodynamic functions of monolayers and nanotubes with various chirality and diameters are calculated on the basis of the obtained phonon frequencies. It is established that the phonon contribution to the nanotube strain energy is small, but may be important for an accurate estimate of the stability of the nanotubes of small diameters. The calculated results show that the thermal contributions to Helmholtz free energy are positive; thereby they slightly reduce the stability of ZrS2 and HfS2 nanotubes at elevated temperatures. © 2019 Wiley Periodicals, Inc.
Access barriers to genetic services for Spanish‐speaking families in states with rapidly growing migrant populations
Authors: Gene Hallford Henry , Coffman Mary Ann , Obregon‐Tito Alexandra Juana , Morales Anayeli Herrera , Williamson Dean Lori
Published: December 2019

Hispanics are among the fastest growing U.S. population segments, accounting for the majority of growth since 2000. Hispanics are heterogeneous and include foreign‐born and U.S. citizens, monolingual fluent English speakers, monolingual Spanish‐speakers, multilingual speakers, and socioeconomically and educationally diverse subgroups. States within the central United States (U.S.), referred to as the Heartland, have numerically small Hispanic populations, but rapidly growing Hispanic populations that are expanding faster than the overall U.S. Hispanic population. The Hispanic populations across the U.S. are widely known to be medically underserved. This qualitative study identifies barriers native Spanish‐speakers experience when locating and accessing genetic services for their children. After providing informed consent, 29 parents in three Heartland states were interviewed and asked about their awareness of available genetic services, utilization of available services and difficulties they encountered when using them. Interviewees reported delayed genetic service referrals, limited availability and inadequate interpretation services, verbal and written communication problems during clinic visits, culturally incongruent healthcare expectations and limited appreciation for how genetic services benefit them. Necessary efforts to understand and improve genetic service access and usefulness for Hispanic populations are underway in the Heartland and elsewhere and should continue to be expanded.
A novel electroconductive interface based on Fe3O4 magnetic nanoparticle and cysteamine functionalized AuNPs: Preparation and application as signal amplification element to minoring of antigen‐antibody immunocomplex and biosensing of prostate cancer
Authors: Farshchi Fatemeh , Hasanzadeh Mohammad , Mokhtarzadeh Ahad
Published: December 2019

In this study, a novel electroconductive interface was prepared based on Fe3O4 magnetic nanoparticle and cysteamine functionalized gold nanoparticle. The engineered interface was used as signal amplification substrate in the electrochemical analysis of antibody‐antigen binding. For this purpose, biotinilated‐anti‐prostate‐specific antigen (PSA) antibody was bioconjugated with iron oxide magnetic nanoparticles (Fe3O4) and drop‐casted on the surface of glassy carbon electrode (GCE). Also, secondary antibody (HRP‐Ab2) encapsulated on gold nanoparticles caped by cysteamine was immobilized on the surface of GCE modified electrode. A transmission electron microscopy images shows that a sandwich immunoreaction was done and binding of Ab1 and Ab2 performed successfully. Various parameters of immunoassay, including the loading of magnetic nanoparticles, the amount of gold nanoparticle conjugate, and the immunoreaction time, were optimized. The detection limit of 0.001 μg. L−1 of PSA was obtained under optimum experimental conditions. It is found that such magneto‐bioassay could be readily used for simultaneous parallel detection of multiple proteins by using multiple inorganic metal nanoparticle tracers and are expected to open new opportunities for early stage diagnosis of cancer in near future.
Residual tumor volume discriminates prognosis after surgery for neuroendocrine liver metastasis
Authors: Kasai Yosuke , Hirose Kenzo , Corvera Carlos U. , Kim Grace E. , Hope Thomas A. , Shih Brandon E. , Harun Nusrat , Kim Mi‐Ok , Warren Robert S. , Bergsland Emily K. , Nakakura Eric K.
Published: December 2019

Background and Objectives

We developed objective measurements of preoperative and residual tumor volume, and debulking rate, to evaluate their prognostic value for neuroendocrine liver metastasis (NELM).

Methods

Seventy‐three patients who underwent surgery for NELM were analyzed retrospectively. Indices of preoperative and postoperative residual tumor volume (pre‐volume index [VI] and post‐VI) were calculated as the sum of the cubes of individual tumor diameters on preoperative and postoperative imaging, respectively. The debulking rate (%) was calculated as 100 − 100 × post‐VI/pre‐VI. The classification and regression trees method was used to classify pre‐VI and post‐VI.

Results

Overall survival (OS) was discriminated by preoperative tumor volume (5‐year OS rates, 87.8% for low pre‐VI and 60.1% for high pre‐VI; P = .037) and residual tumor volume (5‐year OS rates, 88.1% for low post‐VI and 24.8% for high post‐VI; P < .001). In contrast, debulking rates of 100%, ≥90%, and <90% did not discriminate OS (5‐year OS rates, 88.0%, 61.9%, and 58.9%, respectively, not significant). In multivariate analysis, residual tumor volume (high post‐VI, hazard ratio, 6.40; 95% confidence interval, 1.45‐32.3) was an independent prognostic factor for OS.

Conclusions

Objective measurement of tumor volume demonstrates that residual tumor volume is prognostic after surgery for NELM.
Highly ordered molecularly imprinted mesoporous silica for selective removal of bisphenol A from wastewater
Authors: Wu Jinyi , Tan Lei , Li Yuling , Wu Xiaotong , Liang Yong
Published: December 2019

Selective removal of bisphenol A from wastewater is quite challenging primarily because of its low concentration and matrix complexity. To this end, according to the molecular structure of bisphenol A, we designed a functional monomer for the preparation of molecularly imprinted mesoporous silica using click chemistry reaction. The resultant bisphenol A imprinted mesoporous silica was characterized by transmission electron microscopy, small angle X‐ray diffraction, and N2 adsorption–desorption experiments. The results indicated that the bisphenol A imprinted mesoporous silica possessed a highly ordered periodic hexagonal mesostructure with the Brunauer–Emmett–Teller surface area of 944.28 m2/g. The bisphenol A imprinted mesoporous silica showed fast adsorption kinetics and the saturated adsorption capacity reached up to 88.6 mg/g at pH 6.5, and with relative selectivity factors ranged from 1.06 to 3.20. The adsorption efficiency of the bisphenol A imprinted mesoporous silica was above 97.96% after five extraction/elution cycles. The bisphenol A imprinted mesoporous silica was further applied to the selective removal of bisphenol A from real wastewater samples and showed great promise in practical applications.
Using Mountain Lion Habitat Selection in Management
Authors: Dellinger Justin A. , Cristescu Bogdan , Ewanyk Jonathan , Gammons Daniel J. , Garcelon David , Johnston Phillip , Martins Quinton , Thompson Craig , Vickers T. Winston , Wilmers Christopher C. , Wittmer Heiko U. , Torres Steven G.
Published: December 2019

Wildlife agencies are generally tasked with managing and conserving species at state and local levels simultaneously. Thus, it is necessary for wildlife agencies to understand basic ecological processes of a given species at multiple scales to aid decision making at commensurately varied spatial and behavioral scales. Mountain lions (Puma concolor) occur throughout California, USA, and are at the center of a variety of management and conservation issues. For example, they are genetically and demographically at risk in 1 region yet apparently stable and negatively affecting endangered species in another. Currently, no formal plan exists for mountain lions in California to deal with these diverse scenarios involving issues of local mountain lion population viability and problems related to predation of endangered species. To facilitate development of a state‐wide management and conservation plan, we quantified habitat selection by mountain lions at 2 spatial scales across the range of environmental conditions in which the species is found in California. Our analyses used location data from individuals (n = 263) collared across the state from 2001–2019. At the home range scale, mountain lions selected habitat to prioritize meeting energetic demands. At the within home range scale, mountain lions avoided areas of human activity. Further, our analyses revealed 165,350–170,085 km2, depending on season, of suitable mountain lion habitat in California. Fifty percent of the suitable habitat was on unprotected lands and thus vulnerable to development. These habitat selection models will help in the development of a state‐wide conservation and management plan for mountain lions in California by guiding mountain lion population monitoring through time, prioritization of habitat to be conserved for maintaining demographic connectivity and gene flow, and efforts to mediate mountain lion‐prey interactions. Our work and application area will help with wildlife policy and management decisions related to depredation problems at the local scale and issues of habitat connectivity at the statewide scale. © 2019 The Wildlife Society.
Seismic Survey Design and Effects on Maternal Polar Bear Dens
Authors: Wilson Ryan R. , Durner George M.
Published: December 2019

Large‐scale industrial activities can have negative effects on wildlife populations. Some of these effects, however, could be reduced with effective planning prior to development. The Coastal Plain of the Arctic National Wildlife Refuge, in northeastern Alaska, USA, is an important maternal denning area for polar bears (Ursus maritimus). Recent legislation has opened the area for potential oil and gas development. As a result, there is interest in conducting winter seismic surveys across the area that could disturb denning female polar bears and lead to decreased cub survival. We sought to demonstrate how different seismic survey designs, with and without aerial den detection surveys, could affect the level of potential effect on denning polar bears during spring (Feb–Apr). We developed 5 hypothetical seismic survey designs for a portion of the Coastal Plain ranging from no spatial or temporal restrictions on activities to explicit consideration of when and where operations can occur. We evaluated how many dens might be disturbed by seismic surveys and the average distance activity came within simulated polar bear dens. Survey design had a large effect on the estimated number of dens that could be disturbed; the scenario with the highest spatial and temporal specificity reduced the number of dens disturbed by >90% compared to the scenario with no restrictions on when and where activity could occur. The use of an aerial den detection survey prior to seismic activity further reduced the number of dens disturbed by 68% across all scenarios. The scenario with the highest spatial and temporal specificity always had the lowest level of disturbance for all scenarios with and without the aerial survey included. Our study suggests that large reductions in the probability of disturbance can occur through careful planning on the timing and distribution of proposed activities even when surveys are planned in areas with a high density of polar bear dens. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.
Hunting and Nesting Phenology Influence Gobbling of Wild Turkeys
Authors: Wakefield Calvin T. , Wightman Patrick H. , Martin James A. , Bond Bobby T. , Lowrey D. Kevin , Cohen Bradley S. , Collier Bret A. , Chamberlain Michael J.
Published: December 2019

Wild turkeys (Meleagris gallopavo) use a polygynous mating system whereby males engage in multiple courtship behaviors, including vocalizations (gobbling) to attract females and compete with other males for breeding opportunities. Males must balance the risk of courtship behaviors with the reproductive potential of each courtship behavior. Male turkeys are primarily hunted during the reproductive period, so the associated risk of courtship behaviors is increased. Many state agencies attempt to set hunting season frameworks that maximize hunter satisfaction by allowing hunting when gobbling activity is greatest and most females are theoretically incubating nests, but the relationship between gobbling activity and nesting phenology is unclear. We used autonomous recording units and global positioning system transmitters to monitor gobbling activity by male turkeys and reproductive behaviors of female turkeys in the Piedmont region of Georgia, USA. We used 13,177 gobbles, behavioral data from 82 females during the reproductive season, and daily estimates of harvest of males by hunters to examine relationships between daily gobbling activity, cumulative removal of males, and reproductive behaviors (laying, incubating) of females during 2017–2018. We observed a weak negative relationship between daily gobbling activity and gobbling activity the following day. As the reproductive season progressed, gobbling activity decreased. As the proportion of females engaged in laying or incubating behaviors increased, expected daily gobbling activity increased. Conversely, we observed that hunting and removal of males had a negative effect on daily gobbling activity, and this effect was disproportionately greater than the positive effect of female reproductive behaviors. Our findings suggest that hunting and removal of males are important determinants of gobbling activity, and that corresponding reductions in gobbling activity may have mediating effects on the mating system of wild turkeys. © 2019 The Wildlife Society.
Spatial variability of sediment methane production and methanogen communities within a eutrophic reservoir: Importance of organic matter source and quantity
Authors: Berberich Megan E. , Beaulieu Jake J. , Hamilton Trinity L. , Waldo Sarah , Buffam Ishi
Published: December 2019

Freshwater reservoirs are an important source of the greenhouse gas methane (CH4) to the atmosphere, but global emission estimates are poorly constrained (13.3–52.5 Tg C yr−1), partially due to extreme spatial variability in emission rates within and among reservoirs. Spatial heterogeneity in the availability of organic matter (OM) for biological CH4production by methanogenic archaea may be an important contributor to this variation. To investigate this, we measured sediment CH4potential production rates, OM source and quantity, and methanogen community composition at 15 sites within a eutrophic reservoir in Ohio, USA. CH4production rates were highest in the shallow riverine inlet zone of the reservoir, even when rates were normalized to OM quantity, indicating that OM was more readily utilized by methanogens in the riverine zone than in the transitional or lacustrine zones. Sediment stable isotopes and C:N indicated a greater proportion of terrestrial OM in the particulate sediment of this zone. Methanogens were present at all sites, but the riverine zone contained a higher relative abundance of methanogens capable of acetoclastic and methylotrophic methanogenesis, likely reflecting differences in decomposition processes or OM quality. While we found that methane potential production rates were negatively correlated with autochthonous carbon in particulate sediment OM, rates were positively correlated with indicators of autochthonous carbon in the porewater dissolved OM. It is likely that both dissolved and particulate sediment OM affect CH4production rates, and that both terrestrial and aquatic OM sources are important in the riverine methane production hot spot.
Corrosion and corrosive‐wear behaviors of a high strength and toughness Cu–15Ni–8Sn alloy in seawater
Authors: Cheng Jinjuan , Wang Zheming , Gan Xueping , Lei Qian , Li Zhou , Zhou Kechao
Published: December 2019

The Cu–15Ni–8Sn alloy with high strength and toughness is a common bearing alloy, while it is often subjected to premature failure in service due to corrosion and wear. Therefore, the corrosion and wear behaviors of an ultra‐high‐strength and toughness Cu–15Ni–8Sn (wt%) alloy fabricated by hot isostatic pressing were investigated in this study. The results indicated that intergranular corrosion and pits were observed when the studied alloy was immersed into seawater for 30 days. When the Cu–15Ni–8Sn alloy slid in seawater, there was a synergistic effect between corrosion and wear. With the increase of normal load, the synergistic effect weakened initially and then enhanced the interaction between corrosion and wear changed from negative to positive, and the main wear mechanisms transferred from abrasive wear into delamination.
SAXS Investigation on Morphological Change in Lamellar Structures During Propagation Steps of Graft‐Type Polymer Electrolyte Membranes for Fuel Cell Applications
Authors: Tap Tran Duy , Nguyen La Ly , Zhao Yue , Hasegawa Shin , Sawada Shin‐ichi , Hung Nguyen Quang , Tuyen Luu Anh , Maekawa Yasunari
Published: December 2019

The changes of the lamellar periods (L1D), thickness of lamellar crystals (Lc), and amorphous layers (La) within the stacked lamellae of poly(styrenesulfonic acid)‐grafted poly(ethylene‐co‐tetrafluoroethylene) polymer electrolyte membranes (ETFE‐PEMs), induced by the preparation and water‐absorbing steps are investigated using the small‐angle X‐ray scattering method. The L1D values of all the samples quickly increase at a grafting degree (GD) range of less than 19% and then level off. The solvent‐induced recrystallization is observed at the early stage of grafting (GD < 10%) and at successive sulfonation and hydration steps. The L1D, La, and Lc of dry and hydrated PEMs show similar values at higher GD ranges (>34%), leading to the conclusion that most water molecules in the PEMs with higher GDs exist at the outside of the lamellar stacks. Accordingly, for the PEMs with low GD (<19%), all the hydrophilic graft‐polymers (ion‐channels) locate in the lamellar stacks and are strongly restricted by lamellar crystalline layers, which suppress the swelling of the PEMs. The unique lamellar structures of ETFE‐PEMs characterized by La and Lc are well connected with the high conductance and mechanical properties of the membranes, and are suitable for fuel cell applications.
Accelerating Thermal Stabilization by Pyrolytic Lignin for Partially Bio‐Based Carbon Fiber Precursor
Authors: Shi Hui , Ouyang Qin , Wang Jingyu , Hao Jianwei , Huang Xianbo
Published: December 2019

In this study, a partially bio‐based carbon fiber (CF) precursor is prepared by blending 32 wt% of pyrolytic lignin (PyL) with 68 wt% of poly(acrylonitrile‐co‐itaconic acid) (PANIA), and the effect of PyL on forming conjugated ladder structure during stepwise thermal stabilization is studied. The results of X‐ray photoelectron spectroscopy (XPS) reveal that PyL accelerates the formation of conjugated ladder structure at 230 °C during thermal stabilization for PANIA/PyL, which is 15 °C lower and 13 min earlier than PANIA. The acceleration on forming thermally stable conjugated ladder structure can be confirmed through Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Moreover, the fiber stabilized at 230 °C is subsequently made into PANIA/PyL‐230 CF, which has relatively higher‐ordered graphitic structure and dense morphology without voids. The mechanism of PyL accelerating the formation of conjugated ladder structure during thermal stabilization is discussed.
A novel 169Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer
Authors: Famulari Gabriel , Duclos Marie , Enger Shirin A.
Published: December 2019

Purpose

Intensity modulated brachytherapy (IMBT) is a novel high dose rate brachytherapy (HDR BT) technique which incorporates static or dynamic shielding to increase tumor coverage and/or spare healthy tissues. The purpose of this study is to present a novel delivery system (AIM‐Brachy) design that can enable dynamic‐shield IMBT for prostate cancer.

Methods

The AIM‐Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169Yb source. Conventional HDR BT (10 Ci 192Ir) and IMBT (18 Ci 169Yb) plans were generated for 12 patients using an in‐house column generation‐based optimizer, coupled to a Geant4‐based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors (1 mm, 2 mm, and 3 mm) and rotational errors (5, 10 and 15) on clinically relevant parameters (PTV D90 and urethra D10).

Results

The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3%  4.7%, without change to other plan quality indices (PTV V100, V150, V200, bladder V75, rectum V75, HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors (1 mm, 5), the overall tolerance was <2%.

Conclusions

The AIM‐Brachy system was proposed to deliver dynamic‐shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra‐sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.
Influence of contrast agent dispersion on bolus‐based MRI myocardial perfusion measurements: A computational fluid dynamics study
Authors: Martens Johannes , Panzer Sabine , van den Wijngaard Jeroen , Siebes Maria , Schreiber Laura M.
Published: December 2019

Purpose

Bolus‐based dynamic contrast agent (CA) perfusion measurements of the heart are subject to systematic errors due to CA bolus dispersion in the coronary arteries. To better understand these effects on quantification of myocardial blood flow and myocardial perfusion reserve (MPR), an in‐silico model of the coronary arteries down to the pre‐arteriolar vessels has been developed.

Methods

In this work, a computational fluid dynamics analysis is performed to investigate these errors on the basis of realistic 3D models of the left and right porcine coronary artery trees, including vessels at the pre‐arteriolar level. Using advanced boundary conditions, simulations of blood flow and CA transport are conducted at rest and under stress. These are evaluated with regard to dispersion (assessed by the width of CA concentration time curves and associated vascular transport functions) and errors of myocardial blood flow and myocardial perfusion reserve quantification.

Results

Contrast agent dispersion increases with traveled distance as well as vessel diameter, and decreases with higher flow velocities. Overall, the average myocardial blood flow errors are −28% ± 16% and −8.5% ± 3.3% at rest and stress, respectively, and the average myocardial perfusion reserve error is 26% ± 22%. The calculated values are different in the left and right coronary tree.

Conclusion

Contrast agent dispersion is dependent on a complex interplay of several different factors characterizing the cardiovascular bed, including vessel size and integrated vascular length. Quantification errors evoked by the observed CA dispersion show nonnegligible distortion in dynamic CA bolus‐based perfusion measurements. We expect future improvements of quantitative perfusion measurements to make the systematic errors described here more apparent.
Influence of particulate surface treatment on physical, mechanical, thermal, and dielectric behavior of epoxy/hexagonal boron nitride composites
Authors: Agrawal Alok , Chandrakar Saurabh
Published: December 2019

Physical, mechanical, thermal, and dielectric behavior of surface modified hexagonal boron nitride (hBN) in epoxy matrix was investigated in this paper. Effective treatment of microsize boron nitride involved silane coupling agent, (γ‐aminopropyl)triethoxysilane such that the coating resulted from the treatment amounted to 2% of the weight of silane coupling agent of the treated BN. The present work revealed that the chemical treatment of BN surface could effectively enhance the adhesion between matrix and filler material. The dispersion and wettability of the BN powder in epoxy matrix after surface treatment were improved. These imparted improved physical and excellent mechanical and thermal properties to the developed material. The experimental study on thermal properties of fabricated composites indicated that incorporation of modified particles exhibits improved glass transition temperature. As filler loading increases, coefficient of thermal expansion of composite decreases which further decreases when treated filler were used. Further, appreciable improvement in thermal conductivity is obtained when treated hBN is used in place of untreated one. The dielectric properties are investigated for wide frequency range and filler content and found to be increased with hBN content and decrease with frequency enhancement. Furthermore, mechanical properties of such composites were also largely enhanced when treated fillers were used. With modified properties, the presently developed material is suitable for microelectronic applications.
Resonant Acoustic® Mixing: Processing and Safety
Authors: Andrews Matthew R. , Collet Christelle , Wolff Aurihona , Hollands Chris
Published: December 2019

New processing technologies are allowing researchers, industry and academia to probe new materials space not previously achievable. These technologies include additive manufacturing and Resonant Acoustic® Mixing (RAM) which are being demonstrated to reduce processing times, environmental impact and of course cost. With the introduction of any new technology it is imperative that users, managers and national bodies provide the resources and time to determine, understand and provide guidance associated with the safe operating envelope. Combining the RAM with energetic materials requires numerous steps and iterations to generate the required knowledge. This paper is divided into three parts; the first provides a comparison of existing process technologies for energetic materials and how the community has approached using RAM for each of the energetic material sectors. The second part of the paper provides a summary of a review on how RAM users had provided safety assurance in using the technology with energetic materials. The third part covers how the community is using fundamental and applied research to continue in understanding the technology and where the benefits may lie. It is noted that this field is young therefore information contained herein will change in the future.