bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elephants in the understory: opposing direct and indirect effects of consumption and ecosystem engineering by megaherbivores
Authors: Coverdale Tyler C. , Kartzinel Tyler R. , Grabowski Kathryn L. , Shriver Robert K. , Hassan Abdikadir A. , Goheen Jacob R. , Palmer Todd M. , Pringle Robert M. 
Published: August 2016

AbstractPositive indirect effects of consumers on their resources can stabilize food webs by preventing overexploitation, but the coupling of trophic and non‐trophic interactions remains poorly integrated into our understanding of community dynamics. Elephants engineer African savanna ecosystems by toppling trees and breaking branches, and although their negative effects on trees are well documented, their effects on small‐statured plants remain poorly understood. Using data on 117 understory plant taxa collected over 7 yr within 36 1‐ha experimental plots in a semi‐arid Kenyan savanna, we measured the strength and direction of elephant impacts on understory vegetation. We found that elephants had neutral effects on most (83–89%) species, with a similar frequency of positive and negative responses among the remainder. Overall, estimated understory biomass was 5–14% greater in the presence of elephants across a range of rainfall levels. Whereas direct consumption likely accounts for the negative effects, positive effects are presumably indirect. We hypothesized that elephants create associational refuges for understory plants by damaging tree canopies in ways that physically inhibit feeding by other large herbivores. As predicted, understory biomass and species richness beneath elephant‐damaged trees were 55% and 21% greater, respectively, than under undamaged trees. Experimentally simulated elephant damage increased understory biomass by 37% and species richness by 49% after 1 yr. Conversely, experimentally removing elephant damaged branches decreased understory biomass by 39% and richness by 30% relative to sham‐manipulated trees. Camera‐trap surveys revealed that elephant damage reduced the frequency of herbivory by 71%, whereas we detected no significant effect of damage on temperature, light, or soil moisture. We conclude that elephants locally facilitate understory plants by creating refuges from herbivory, which countervails the direct negative effects of consumption and enhances larger‐scale biomass and diversity by promoting the persistence of rare and palatable species. Our results offer a counterpoint to concerns about the deleterious impacts of elephant “overpopulation” that should be considered in debates over wildlife management in African protected areas: understory species comprise the bulk of savanna plant biodiversity, and their responses to elephants are buffered by the interplay of opposing consumptive and non‐consumptive interactions.
Early warning of critical transitions in biodiversity from compositional disorder
Authors: Doncaster C. Patrick , Alonso Chávez Vasthi , Viguier Clément , Wang Rong , Zhang Enlou , Dong Xuhui , Dearing John A. , Langdon Peter G. , Dyke James G. 
Published: August 2016

AbstractGlobal environmental change presents a clear need for improved leading indicators of critical transitions, especially those that can be generated from compositional data and that work in empirical cases. Ecological theory of community dynamics under environmental forcing predicts an early replacement of slowly replicating and weakly competitive “canary” species by slowly replicating but strongly competitive “keystone” species. Further forcing leads to the eventual collapse of the keystone species as they are replaced by weakly competitive but fast‐replicating “weedy” species in a critical transition to a significantly different state. We identify a diagnostic signal of these changes in the coefficients of a correlation between compositional disorder and biodiversity. Compositional disorder measures unpredictability in the composition of a community, while biodiversity measures the amount of species in the community. In a stochastic simulation, sequential correlations over time switch from positive to negative as keystones prevail over canaries, and back to positive with domination of weedy species. The model finds support in empirical tests on multi‐decadal time series of fossil diatom and chironomid communities from lakes in China. The characteristic switch from positive to negative correlation coefficients occurs for both communities up to three decades preceding a critical transition to a sustained alternate state. This signal is robust to unequal time increments that beset the identification of early‐warning signals from other metrics.
Increase in cannabis use may indirectly affect the health status of a freshwater species
Authors: Parolini Marco , Castiglioni Sara , Magni Stefano , Della Torre Camilla , Binelli Andrea 
Published: August 2016

Abstract

Cannabis is the most used illicit drug worldwide and in some countries a new regulatory policy makes it legal under some restrictions. This situation could lead to a substantial increase in environmental levels of the cannabis active principle (Δ-9-tetrahydrocannabinol [Δ-9-THC]) and its main metabolite, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH). Although previous studies have highlighted the toxicity of Δ-9-THC, the adverse effects of THC-COOH on aquatic organisms is completely unknown, even though such effects could be more significant because the environmental concentrations of THC-COOH are higher than those of the parent compound. The present study aimed to assess oxidative and genetic damage to the zebra mussel (Dreissena polymorpha) because of 14-d exposures to 3 THC-COOH concentrations, mimicking a current environmental situation (100 ng/L), as well as exposure to 2 possible worst-case scenarios (500 ng/L and 1000 ng/L), because of the potential increase in THC-COOH in surface waters. Variations in the activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) were measured, as well as levels of lipid peroxidation and protein carbonyl content. Genetic injuries were investigated by single-cell gel electrophoresis assay, DNA diffusion assay, and the micronucleus test. A significant imbalance in antioxidant defense enzymes was noted in response to the 3 tested concentrations, whereas oxidative damage was noted only at the higher one. Moreover, an increase in DNA fragmentation in zebra mussel hemocytes, but no fixed genetic damage, was found. Although the results showed that THC-COOH toxicity was lower than that of Δ-9-THC, the increase in cannabis use might increase its levels in freshwaters, enhancing its hazard to bivalves and likely to the whole aquatic community. Environ Toxicol Chem 2017;36:472–479. © 2016 SETAC
Population modeling for pesticide risk assessment of threatened species—A case study of a terrestrial plant, Boltonia decurrens
Authors: Schmolke Amelie , Brain Richard , Thorbek Pernille , Perkins Daniel , Forbes Valery 
Published: August 2016

Abstract

Although population models are recognized as necessary tools in the ecological risk assessment of pesticides, particularly for species listed under the Endangered Species Act, their application in this context is currently limited to very few cases. The authors developed a detailed, individual-based population model for a threatened plant species, the decurrent false aster (Boltonia decurrens), for application in pesticide risk assessment. Floods and competition with other plant species are known factors that drive the species’ population dynamics and were included in the model approach. The authors use the model to compare the population-level effects of 5 toxicity surrogates applied to B. decurrens under varying environmental conditions. The model results suggest that the environmental conditions under which herbicide applications occur may have a higher impact on populations than organism-level sensitivities to an herbicide within a realistic range. Indirect effects may be as important as the direct effects of herbicide applications by shifting competition strength if competing species have different sensitivities to the herbicide. The model approach provides a case study for population-level risk assessments of listed species. Population-level effects of herbicides can be assessed in a realistic and species-specific context, and uncertainties can be addressed explicitly. The authors discuss how their approach can inform the future development and application of modeling for population-level risk assessments of listed species, and ecological risk assessment in general. Environ Toxicol Chem 2017;36:480–491. © 2016 SETAC
High‐order discontinuous Galerkin nonlocal transport and energy equations scheme for radiation hydrodynamics
Authors: Holec M. , Limpouch J. , Liska R. , Weber S. 
Published: August 2016

SummaryThe nonlocal theory of the radiative energy transport in laser‐heated plasmas of arbitrary ratio of the characteristic inhomogeneity scale length to the photon mean free paths is applied to define the closure relations of a hydrodynamic system. The corresponding transport phenomena cannot be described accurately using the Chapman–Enskog approach, that is, with the usual fluid approach dealing only with local values and derivatives. Thus, we directly solve the photon transport equation allowing one to take into account the effect of long‐range photon transport. The proposed approach is based on the Bhatnagar–Gross–Krook collision operator using the photon mean free path as a unique parameter. Such an approach delivers a calculation efficiency and an inherent coupling of radiation to the fluid plasma parameters in an implicit way and directly incorporates nonequilibrium physics present under the condition of intense laser energy deposition due to inverse bremsstrahlung. In combination with a higher order discontinuous Galerkin scheme of the transport equation, the solution obeys both limiting cases, that is, the local diffusion asymptotic usually present in radiation hydrodynamics models and the collisionless transport asymptotic of free‐streaming photons. In other words, we can analyze the radiation transport closure for radiation hydrodynamics and how it behaves when deviating from the conditions of validity of Chapman–Enskog method, which is demonstrated in the case of exact steady transport and approximate multigroup diffusion numerical tests. As an application, we present simulation results of intense laser‐target interaction, where the radiative energy transport is controlled by the mean free path of photons. Copyright © 2016 John Wiley & Sons, Ltd.
Divergence preserving reconstruction of the nodal components of a vector field from its normal components to edges
Authors: Liska Richard , Shashkov Mikhail 
Published: August 2016

SummaryWe have developed a new divergence preserving method for the reconstruction of the Cartesian components of a vector field from the orthogonal projection of a vector field to the normals to edges in two dimensional. In this method, discrete divergences computed from the nodal components and from the normal ones are exactly the same. Our new method consists of two stages. At the first stage, we use an extended version of the local procedure described in [J. Comput. Phys., 139:406–409, 1998] to obtain a ‘reference’ nodal vector. This local procedure is exact for linear vector fields; however, the discrete divergence is not preserved. Then, we formulate a constrained optimization problem, in which this reference vector plays the role of a target, and the divergence constraints are enforced by using Lagrange multipliers. It leads to the solution of ‘elliptic’ like discrete equations for the cell‐centered Lagrange multipliers. The new global divergence preserving method is exact for linear vector fields. We describe all details of our new method and present numerical results, which confirm our theory. Copyright © 2016 John Wiley & Sons, Ltd.
The Skewness Implied in the Heston Model and Its Application
Authors: Zhang Jin E. , Zhen Fang , Sun Xiaoxia , Zhao Huimin 
Published: August 2016

AbstractIn this paper, we provide an exact formula for the skewness of stock returns implied in the Heston (1993) model by using a moment‐computing approach. We compute the moments of It integrals by using It's Lemma skillfully. The model's affine property allows us to obtain analytical formulas for cumulants. The formulas for the variance and the third cumulant are written as time‐weighted sums of expected instantaneous variance, which are neater and more intuitive than those obtained with the characteristic function approach. Our skewness formula is then applied in calibrating Heston's model by using the market data of the CBOE VIX and SKEW. © 2016 Wiley Periodicals, Inc. Jrl Fut Mark 37:211–237, 2017
Latin American protected areas: Protected from chemical pollution?
Authors: Rodríguez-Jorquera Ignacio A , Siroski Pablo , Espejo Winfred , Nimptsch Jorge , Choueri Paloma Gusso , Choueri Rodrigo Brasil , Moraga Claudio A , Mora Miguel , Toor Gurpal S 
Published: August 2016

Abstract

Protected areas (PAs) are critically important means to preserve species and maintain natural ecosystems. However, the potential impacts of chemical pollution on PAs are seldom mentioned in the scientific literature. Research on the extent of the occurrence of chemical pollution inside PAs and in-depth assessments of how chemical contaminants may adversely affect the maintenance of species abundance, species survival, and ecosystem functions are scarce to nonexistent. We investigated 1) the occurrence of chemical contaminants inside 119 PAs in Latin America from publically available databases, and 2) reviewed case studies of chemical contaminants and pollution in 4 Latin American PAs. Cases of chemical pollution and contamination inside Latin American PAs mostly originated from sources such as mining, oil, and gas extraction. To date, the focus of the research on chemical pollution research inside Latin American PAs has been primarily on the detection of contamination, typically limited to trace metals. Where management actions have occurred, they have been reactive rather than proactive. Protected areas established in wetlands are the most affected by chemical pollution. Based on the information from the pollution and/or contamination occurrence and the case studies analyzed, Latin American PAs are not well safeguarded from chemical pollution, resulting in both challenges and opportunities to conserve biodiversity and ecosystems. Integr Environ Assess Manag 2017;13:360–370. © 2016 SETAC

Key Points
Despite the fact that chemical pollution can harm free-range organism populations, research on the impact of chemical pollution inside protected areas (PAs) is rarely considered. Our database review and case studies showed that Latin American PAs are not necessarily safeguarded from chemical pollution. Chemical pollution had affected biodiversity inside Latin American PAs, but management actions to avoid the damage have rarely occurred, and when present, they have been reactive rather than proactive, which is inadequate and inefficient. Aquatic environments might be the most threatened habitats within PAs in Latin America as shown in these database analyses and case studies, thus, PAs established in wetlands are the most vulnerable to chemical pollution.
Anti‐Inflammatory and Anti‐Oxidant Effects of p‐Chloro‐phenyl‐selenoesterol on TNBS‐Induced Inflammatory Bowel Disease in Mice
Authors: Zarzecki Micheli Stéfani , Bortolotto Vandreza Cardoso , Poetini Márcia Rósula , Araujo Stífani Machado , de Paula Mariane Trindade , Roman Silvane Souza , Spiazzi Cristiano , Cibin Franciele Weber Santos , Rodrigues Oscar Endrigo Dorneles , Jesse Cristiano Ricardo , Prigol Marina 
Published: August 2016

ABSTRACTThis study aims to investigate the protective effect of p‐chloro‐phenyl‐selenoesterol [PCS; 0,2 mg/kg; 10 ml/kg i.g.) in colitis induced by 2,4,6‐trinitrobenzene sulfonic acid [TNBS; 2 mg/100 µl 50% ethanol; intrarectally) in mice. Several parameters including weight, length, histological analyses determination, thiobarbituric acid reactive species, reactive species levels, superoxide dismutase, catalase, and myeloperoxidase (MPO) activity of colon were evaluated. The serum levels of tumor necrosis factor alpha [TNF‐α) and interleukin 6 [IL‐6) were also assessed. Treatment with PCS reduced the clinical and histopathologic severity of TNBS‐induced colitis, characterized by colon length reduction and increased colon weight and microscopic intestinal inflammation. The therapeutic effects of PCS in this model were associated with significant decrease in proinflammatory cytokines TNF‐α and IL‐6 and decrease in MPO activity. Furthermore, combined with improvements in inflammatory parameters, treatment with the PCS was able to decrease oxidative stress and to prevent the decrease in antioxidant defenses in animals with TNBS‐induced colitis. This finding suggests that PCS can improve experimental colitis in mice and it could be a potential therapeutic agent for the treatment of patients with IBD. J. Cell. Biochem. 118: 709–717, 2017. © 2016 Wiley Periodicals, Inc.
Pediatric salivary gland carcinomas: Diagnostic and therapeutic management
Authors: Rebours Céleste , Couloigner Vincent , Galmiche Louise , Casiraghi Odile , Badoual Cécile , Boudjemaa Sabah , Chauvin Anthony , Elmaleh Monique , Fresneau Brice , Fasola Sylvie , Garabédian Erea‐Noël , Van Den Abeele Thierry , Orbach Daniel ,   for the Pediatric French Rare Tumor Group
Published: August 2016

Objectives/HypothesisTo analyze clinical presentations, treatment modalities, and evolution of pediatric cases of salivary gland carcinomas to standardize care for these rare diseases.Study DesignMulticentric, retrospective study.MethodsWe included in this retrospective study all children and adolescents (aged ≤18 years) treated from 1992 to 2012 in six pediatric centers in Paris, France. Pathological tumor specimens of these cases were reviewed.ResultsForty‐three children were included (sex ratio male/female = 19/24, median age = 13 years). The parotid gland was the most common (37 cases) location for tumors. Histological subtypes were mucoepidermoid carcinomas (n = 20), acinic cell carcinomas (n = 14), and other (n = 9). Initial fine‐needle aspiration was performed in 15 cases (33%), and was concordant to final diagnosis in three cases (20%). Primary surgery was performed in 42 patients, leading to a complete microscopic resection in 80%. Associated lymph node dissection was performed in 28 patients (homolateral: 27, bilateral: 1) and showed lymph node metastases in only two patients. One patient had distant metastases. Adjuvant irradiation was delivered to 11 patients (median: 60 Gy; range: 50–65) and chemotherapy in five cases. After a median follow‐up of 5 years, six tumors relapsed, but no deaths occurred.ConclusionsChildhood salivary gland carcinomas have a good prognosis despite possible recurrences. Treatment is mainly based on surgery, with simultaneous node dissection in cases of clinical or radiologic node enlargement. Radiation therapy seems to be restricted to inoperable high‐grade tumors or after recurrence.Level of Evidence4 Laryngoscope, 127:140–147, 2017
Guaranteed error bounds in homogenisation: an optimum stochastic approach to preserve the numerical separation of scales
Authors: Paladim D. A. , Moitinho de Almeida J. P. , Bordas S. P. A. , Kerfriden P. 
Published: August 2016

AbstractThis paper proposes a new methodology to guarantee the accuracy of the homogenisation schemes that are traditionally employed to approximate the solution of PDEs with random, fast evolving diffusion coefficients. More precisely, in the context of linear elliptic diffusion problems in randomly packed particulate composites, we develop an approach to strictly bound the error in the expectation and second moment of quantities of interest, without ever solving the fine‐scale, intractable stochastic problem. The most attractive feature of our approach is that the error bounds are computed without any integration of the fine‐scale features. Our computations are purely macroscopic, deterministic and remain tractable even for small scale ratios. The second contribution of the paper is an alternative derivation of modelling error bounds through the Prager–Synge hypercircle theorem. We show that this approach allows us to fully characterise and optimally tighten the interval in which predicted quantities of interest are guaranteed to lie. We interpret our optimum result as an extension of Reuss–Voigt approaches, which are classically used to estimate the homogenised diffusion coefficients of composites, to the estimation of macroscopic engineering quantities of interest. Finally, we make use of these derivations to obtain an efficient procedure for multiscale model verification and adaptation. Copyright © 2016 John Wiley & Sons, Ltd.
The First Record of a Pre‐Columbian Domestic Dog (Canis lupus familiaris) in Brazil
Authors: Guedes Milheira R. , Loponte D. M. , García Esponda C. , Acosta A. , Ulguim P. 
Published: August 2016

AbstractArchaeological excavations of the PSG‐07 earthen mound at Pontal da Barra in Rio Grande do Sul, southern Brazil have revealed the earliest known evidence for the presence of domestic dog (Canis lupus familiaris) in Brazil. This is the first reported pre‐Columbian example in the country. Analysis of morphology, morphometry, and dental enamel laminae identified a left maxillary molar 1, left maxillary molar 2 and attached fragments of the maxilla of C. l. familiaris. A direct radiocarbon date on a fragment of the maxilla provided an age range between 1701 and 1526 cal BP (2σ). This is within the range of other dates for the site, which indicate intermittent occupation between 2024 and 1027 cal BP (2σ). Data from carbon isotope analysis indicates a potential marine diet. However, nitrogen isotope analysis values are lower than expected for a marine diet. The sparse records of pre‐Columbian C.  l. familiaris in the region emphasise the importance of the present work. Copyright © 2016 John Wiley & Sons, Ltd.
Remimazolam: Pharmacologic Considerations and Clinical Role in Anesthesiology
Authors: Wesolowski Alexandra M. , Zaccagnino Michael P. , Malapero Raymond J. , Kaye Alan D. , Urman Richard D. 
Published: August 2016

Midazolam, fentanyl, and propofol are commonly used for sedation in modern anesthesia practice. These agents possess characteristics that have afforded various anesthetics to be delivered and produce relatively safe and effective outcomes. However, each agent has certain drawbacks in clinical practice. Remimazolam, a novel benzodiazepine created out of so‐called soft drug development, is an ultrashort‐acting intravenous sedative‐hypnotic currently being investigated in clinical trials. In this review, we evaluate the recent literature on the use of remimazolam in clinical practice as compared with current sedative agents, and we describe its potential roles for use in sedation. A literature search of the Medline database (2012–May 2016) was performed. Additional references were identified from a review of literature citations, manufacturer reports, and professional meeting abstracts. All premarket studies involving remimazolam as the primary study drug were evaluated. Literature describing the pharmacokinetics and pharmacodynamics of remimazolam, propofol, and midazolam was also included. Phase I and II studies in the United States have shown remimazolam to be a safe and effective option for procedural sedation. Unlike midazolam and propofol, remimazolam undergoes organ‐independent metabolism to an inactive metabolite. Because remimazolam follows first‐order pharmacokinetics, prolonged infusions or higher doses are unlikely to result in accumulation and extended effect, making it favorable for use as an intravenous anesthetic and for sedation in the intensive care unit. It is expected that phase III trials will further describe the niche that remimazolam may be able to occupy in clinical practice. Postmarket cost‐benefit analyses will need to be performed.