bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Temperature Tensile Characteristics of Warm-Mix Asphalt Mixtures
Authors: Yeon Kyu-Seok , Kim Sungun , Lee Hyong-Jong , Kim Kwang W.
Published: May 2014

The tensile strength (St) of warm-mix asphalt (WMA) and hot-mix asphalt (HMA) concretes were measured by indirect tensile strength test at 25, 5, −5, −15, −25 and −35°C. Fracture toughness (Tu) was calculated from each of the St test curves. Two WMA additives and two polymer modifiers were used to produce WMA mixtures at 135°C in the laboratory. All asphalt concretes evaluated in this study showed St increase by temperature decreases, peaking at −15°C or −25°C, then decreasing with further lowering of temperatures. The St values of WMA mixtures were observed to be higher than those of HMA mixtures in most cases at all low temperatures evaluated in this study. After being subjected to differential thermal contraction damage at −15 and/or −20°C, most of the WMA mixtures showed higher St than HMA mixes at severely low temperatures (−25 and −35°C). Therefore, it was concluded that the WMA mixtures had stronger St than HMA mixtures at low temperatures when prepared with the same low-temperature PG binders, even though they were produced at a lower aggregate-heating temperature.
Mechanical Properties Assessment of Concrete Containing Reclaimed Asphalt Pavement Using the Superpave Indirect Tensile Strength Test
Authors: Su Yu-Min , Hossiney Nabil , Tia Mang , Bergin Michael
Published: May 2014

Concrete mixes containing reclaimed asphalt pavement (RAP) were evaluated by the Superpave Indirect Tensile (IDT) strength test. The IDT strength and elastic modulus from Superpave IDT strength test correlated well with the splitting tensile strength and elastic modulus from the conventional concrete tests. Toughness determined by the area under the stress-strain plot up to the maximum stress was found to be capable of differentiating concretes containing different percentage of RAP. The IDT strengths of concrete were seen to decrease as the percentage of RAP and temperature increased. The addition of RAP in concrete noticeably reduced the elastic modulus but increased the toughness.
Quantification of the Structural Stresses in Steel Bridges by Means of the X-Ray Diffraction Technique: The Case of the Bizkaia Bridge (Industrial World Heritage Site in Spain)
Authors: Sánchez-Beitia S. , Barrallo J.
Published: May 2014

One of the most interesting challenges for the scientific community in the field of structural analysis is the development of new non-destructive experimental techniques (NDT). The research presented in this report addresses the applicability of the X-ray diffraction technique for quantification of the on-site stresses in metallic (steel) structures using standard portable equipment. The paper describes the process of obtaining the structural stresses in two zones of the Bizkaia Bridge (Industrial World Heritage), which is located in the Bizkaia province (Spain) between the towns of Portugalete and Las Arenas. In a few cases, applications of the technique have been performed before. The quality of the experimental technique, as well as the usefulness of the on-site methodology in the framework of historical constructions, is presented.
The Cyclic Strain Resistance, Stress Response, Fatigue Life, and Fracture Behavior of a High Performance Alloy Steel
Authors: Manigandan K. , Srivatsan T. S. , Tammana D. , Poorganji B. , Vasudevan V. K.
Published: May 2014

In this paper, the results of a recent study aimed at understanding the role of microstructure on cyclic stress response, cyclic strain resistance, deformation, fatigue life, and fracture behavior of the high strength alloy steel PremoMet 290 is presented and discussed. The cyclic strain amplitude-controlled fatigue properties, deformation, and resultant fracture behavior of the alloy steel specimens are discussed when cyclically deformed over a range of strain amplitudes. The intrinsic mechanisms governing stress response, stress versus strain response fatigue life, deformation, and final fracture behavior are presented and discussed in light of the competing and mutually interactive influences of intrinsic microstructural effects, deformation characteristics of the microstructural constituents, cyclic strain amplitude, and concomitant response stress.
Application of Automation Technology in Fatigue and Fracture Testing and Analysis
Authors: McKeighan Peter C. , Braun Arthur A.
Published: May 2014

Description

These eleven papers emphasize refined experimental methods, new methods and techniques, data analysis and software development.

The common thread throughout these papers is the increasing role of computer automation while performing the test and then interpreting the results once testing is complete. Test automation remains a critical area for developing the tools and techniques required to understand the more difficult problems that face the materials engineer and designer today.

The Automation Task Group within ASTM E08.03, the contributors to this collection of technical papers, revisit the automation research approximately every five years to report and track how testing methods, techniques and tools evolve. Recent efforts on algorithm development promise to provide useful tools to the analyst for interpreting material behavior and coping with the vast amount of data that is typically recorded in the laboratory today.
Evaluation of Fracture Toughness Test Methods for Linepipe Steels2This licence is granted on the condition that clear attribution is given to the author(s) and Natural Resources Canada and, when feasible, that the Crown copyright is acknowledged as follows: © Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2014.
Authors: Kang Jidong , Shen Guowu , Liang Jie , Brophy Kyle , Mendonca Andrew , Gianetto James
Published: May 2014

Reliable evaluation of fracture toughness resistance curves, including both J–resistance (J-R) and crack tip opening displacement–resistance (CTOD-R) curves, is becoming an integral part of pipeline integrity assessment for demanding applications. Using MTS TestSuite Software with Multipurpose Elite, we have successfully realized the automation of fracture toughness test procedures for single-edge bend [SE(B)] test specimens based on ASTM E1820-11 and BSI 7448. The software offers the option to use either load-line displacement (LLD) or crack mouth opening displacement (CMOD) as the control parameter for both shallow- and deep-cracked SE(B) specimens and exports both the J-R and the CTOD-R curves simultaneously. In order to validate the developed software, we have tested two different pipe steels, namely, X60 and X100 steels. The nominal initial crack lengths a/W after precracking were equal to 0.2 and 0.5 for the shallow- and deep-cracked specimens, respectively. A 10% deep side groove was machined after the precracking on each side of the specimen. The results show that for J-R curves, the differences between the LLD and CMOD methods are negligible within the Jmax criteria range. Beyond this range, however, some differences were observed. There was no significant effect of work hardening rate on the J-R curves obtained using either LLD or CMOD for the two pipe steel materials investigated. However, it is worth noting that there were large discrepancies between the ASTM and BSI methods in terms of CTOD-R curve measurements, especially for the shallow-cracked specimens. This was attributed to the fact that the standards use different definitions of CTOD.
Software Tools for a Materials Testing Curriculum
Authors: Leser Christoph , Kelso Frank , Gordon Ali P. , Ohnsted Sherri
Published: May 2014

Instructors of both undergraduate and graduate courses of materials science with a laboratory section employ hands-on sessions to further students’ understanding of key materials behavior principles. A typical solid mechanics laboratory session exposes students to topics such as: tensile, torsion, hardness, fatigue, and fracture testing procedures as well as associated properties and the like. Even though observing the different modes of material deformation and rupture response first-hand fosters a better mastery of the course content, limitations in available “face time” with students, course budget, availability of test devices, etc., are obstacles. Integrating software tools that simulate mechanical testing represents an alternative approach that can potentially transform and enhance the students learning outcomes. The identical graphical user interface is used for conducting both virtual and physical testing of materials. The software tools will aid in the classroom, laboratory, and student self-study for the subjects of a material’s plastic yielding, stress-strain relationships, fatigue, crack growth, and fracture. These same tools are then used in the laboratory to perform physical testing. This integrated virtual/physical curriculum prepares the student in test setup, execution and data analysis and makes the laboratory experience more efficient. It is also instructive for gaining an understanding of the value and limitations of modeling approaches in describing material behavior.
Puerarin protects pancreatic β-cell survival via PI3K/Akt signaling pathway
Authors: Li Zhipeng , Shangguan Zhaoshui , Liu Yijie , Wang Jihua , Li Xuejun , Yang Shuyu , Liu Suhuan
Published: May 2014

Pancreatic β-cell loss because of apoptosis is the major cause of type 1 diabetes (T1D) and late stage T2D. Puerarin possesses anti-diabetic properties; whether it acts directly on pancreatic β-cell is not clear. This study was designed to investigate the effects of puerarin on pancreatic β-cell survival and function. Diabetes was induced in male C57BL/6 mice by a single peritoneal injection of streptozotocin (STZ). Pancreatic β-cell survival and function were assessed in diabetic mice by measuring β-cell apoptosis, β-cell mass, pancreatic insulin content, and glucose tolerance, and in cultured islets and clonial MIN6 β-cells by measuring β-cell viability and apoptosis and glucose-stimulated insulin secretion. We found that pre-treatment with puerarin decreased the incidence of STZ-induced diabetes. Puerarin increased pancreatic β-cell mass via β-cell apoptosis inhibition in diabetic mice, and increased serum insulin, whereas it decreased blood glucose levels and improved glucose tolerance. In cultured islets and MIN6 cells, puerarin protected β-cell from cobalt chloride (CoCl2)-induced apoptosis and restored the impaired capacity of glucose-stimulated insulin secretion. Puerarin protection of β-cell survival involved the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. In conclusion, puerarin protects pancreatic β-cell function and survival via direct effects on β-cells, and its protection of β-cell survival is mediated by the PI3K/Akt pathway. As a safe natural plant extraction, puerarin might serve as a preventive and/or therapeutic approach for diabetes.
Prenatal androgen excess enhances stimulation of the GNRH pulse in pubertal female rats
Authors: Yan Xiaonan , Yuan Chun , Zhao Nannan , Cui Yugui , Liu Jiayin
Published: May 2014

In adolescent girls with polycystic ovary syndrome (PCOS), neuroendocrine derangements manifest after the onset of puberty, characterized by rapid LH pulse frequency. The early mechanism underlying the pubertal regulation of the GNRH/LH pulsatile release in adolescents with PCOS remains uncertain. To determine the effects of prenatal androgen exposure on the activation of GNRH neurons and generation of LH pulse at puberty, we administrated 5α-dihydrotestosterone to pregnant rats and observed serum LH levels and expression of hypothalamic genes in female offspring from postnatal 4 to 8 weeks. The 6-week-old prenatally androgenized (PNA) female rats exhibited an increase in LH pulse frequency. The hypothalamic expression of neurokinin B (Nkb(Tac2)) andLeprmRNA levels in PNA rats increased remarkably before puberty and remained high during puberty, whereas elevatedKiss1mRNA levels were detected only after the onset of puberty. Exogenous kisspeptin, NK3R agonist, and leptin triggered tonic stimulation of GNRH neurons and increased LH secretion in 6-week-old PNA rats. Leptin upregulatedKiss1mRNA levels in the hypothalamus of pubertal PNA rats; however, pretreatment with a kisspeptin antagonist failed to suppress the elevated serum LH stimulated by leptin, indicating that the stimulatory effects of leptin may be conveyed indirectly to GNRH neurons via other neural components within the GNRH neuronal network, rather than through the kisspeptin–GPR54 pathway. These findings validate the hypotheses that NKB and leptin play an essential role in the activation of GNRH neurons and initiation of increased LH pulse frequency in PNA female rats at puberty and that kisspeptin may coordinate their stimulatory effects on LH release.
α-MSH overexpression in the nucleus tractus solitarius decreases fat mass and elevates heart rate
Authors: Eerola K , Rinne P , Penttinen A M , Vähätalo L , Savontaus M , Savontaus E
Published: May 2014

The POMC pathway is involved in the regulation of energy and cardiovascular homeostasis in the hypothalamus and the brain stem. Although the acute effects of POMC-derived peptides in different brain locations have been elucidated, the chronic site-specific effects of distinct peptides remain to be studied. To this end, we used a lentiviral gene delivery vector to study the long-term effects of α-MSH in the nucleus tractus solitarius (NTS) of the brain stem. The α-MSH vector (LVi–α-MSH–EGFP) based on the N-terminal POMC sequence and a control vector (LVi–EGFP) were delivered into the NTS of C57BL/6N male mice fed on a western diet. Effects on body weight and composition, feeding, glucose metabolism, and hemodynamics by telemetric analyses were studied during the 12-week follow-up. The LVi–α-MSH–EGFP-treated mice had a significantly smaller gain in the fat mass compared with LVi–EGFP-injected mice. There was a small initial decrease in food intake and no differences in the physical activity. Glucose metabolism was not changed compared with the control. LVi–α-MSH–EGFP increased the heart rate (HR), which was attenuated by adrenergic blockade suggesting an increased sympathetic activity. Reduced response to muscarinic blockade suggested a decreased parasympathetic activity. Fitting with sympathetic activation, LVi–α-MSH–EGFP treatment reduced urine secretion. Thus, the results demonstrate that long-term α-MSH overexpression in the NTS attenuates diet-induced obesity. Modulation of autonomic nervous system tone increased the HR and most probably contributed to an anti-obesity effect. The results underline the key role of NTS in the α-MSH-induced long-term effects on adiposity and in regulation of sympathetic and parasympathetic activities.
Employer Support for Innovative Work and Employees' Job Satisfaction and Job‐related Stress
Authors: Raykov Milosh
Published: May 2014

Employer Support for Innovative Work and Employees' Job Satisfaction and Job‐related Stress: Milosh RAYKOV. Faculty of Education, University of Malta, Malta—

Objectives

There are high levels of global and national underemployment, but limited information is available on the impact of this phenomenon on the quality of employees' working lives. This study examines the relations among perceived employer support for creative work, different forms of underemployment and employee quality of life, including job satisfaction, perceived job security and job satisfaction.

Methods

The study was performed using cross‐sectional data from the Canadian 2010 Work and Lifelong Learning Survey (WALL), which included 1,042 randomly selected currently employed participants between the ages of 18 and 64 years of age.

Results

The study found a significant inverse association between employer support for innovative work and different forms of underemployment. It also suggested a strong relationship between support for such work and participation in work‐related informal learning. The results from this study confirmed the hypothesis that employer support for creative work is significantly associated with the quality of employees' working lives, as manifested through increased job security and job satisfaction. Employees experiencing greater support for workplace creativity report less job‐related stress. The present study identified relatively low employer support for creative work and significant differences in the perception of support among managers and workers.

Conclusions

The results of this study indicate that employer support for innovative work can mitigate significant underutilization of employee knowledge and skills. Such support can contribute to the reduction of job‐related stress, increased job satisfaction and perceived job security. This kind of support can also improve the quality of life of employees and facilitate creativity and overall organizational and social development.
Time Course of Blood Parameters in Printing Workers with Cholangiocarcinoma
Authors: Kumagai Shinji , Kurumatani Norio , Arimoto Akira , Ichihara Gaku
Published: May 2014

Time Course of Blood Parameters in Printing Workers with Cholangiocarcinoma: Shinji KUMAGAI, et al. Department of Occupational and Environmental Management, University of Occupational and Environmental Health, Japan—

Objectives

We previously reported a cluster of cholangiocarcinoma patients among proof‐printing workers who were exposed to 1,2‐DCP for a long term. The present study was conducted to evaluate blood parameters in these proof‐printing workers during and after exposure.

Methods

Health examination records during employment and after retirement were obtained for ten cholangiocarcinoma patients to analyze their blood parameters. The patients and/or their relatives were also interviewed about lifestyle and occupational history.

Results

All study patients were exposed to 1,2‐DCP for 6−17 years. Red blood cells, hemoglobin, hematocrit, total cholesterol, triglycerides, and fasting plasma glucose were within the standard ranges for almost all patients, but the γ‐glutamyl transpeptidase (γ‐GTP) levels exceeded the standard range during 1,2‐DCP exposure for six patients. Two of the six patients were diagnosed with cholangiocarcinoma during 1,2‐DCP exposure, and the other four patients were diagnosed 1−9 years after termination of exposure. The remaining four patients had γ‐GTP levels within the standard range during 1,2‐DCP exposure, but had increased γ‐GTP levels thereafter, and were diagnosed with cholangiocarcinoma 4−10 years after termination of exposure. Aspartate aminotransferase and alanine aminotransferase levels started to increase following the increase in γ‐GTP levels.

Conclusions

Workers exposed to 1,2‐DCP should be provided with periodic health examinations during and after exposure. In the examination, even small increases in γ‐GTP levels should be considered a signal of early development of cholangiocarcinoma.
A Dislocation Pile-Up Computation for Adiabatic Shear Banding
Authors: Antolovich Stephen D. , Armstrong Ronald W.
Published: May 2014

A model is presented for computing the temperature increase associated with the formation of an adiabatic shear band. The hypothesis is that the heating is supplied by the difference in energy of a pile-up of n dislocations and the energy of n individual dislocations. The heating is assumed to occur within a volume determined by the grain size (i.e. slip band length) and an effective thermal length determined by the dislocation velocity. The model predicts increases in temperature with increasing shear modulus (G), increasing numbers of piled up dislocations (n), increasing Burgers vector (b), increased grain size (d), and increased dislocation velocity (vd). Increasing temperature is also predicted with decreasing heat capacity (c*) and thermal diffusivity (α) as would be expected. The model was applied to low carbon steel for which considerable data are available. Application to low carbon steel gives a temperature increase of about 1400K. The implied result that untempered martensite should be observed after adiabatic shear banding is in agreement with examples cited in the literature. Further investigation into the dynamics of pile-up release and the associated heat transfer mechanisms is discussed.
Geochemistry of acid mine drainage from a coal mining area and processes controlling metal attenuation in stream waters, southern Brazil
Authors: CAMPANER VERIDIANA P. , LUIZ-SILVA WANILSON , MACHADO WILSON
Published: May 2014

Acid drainage influence on the water and sediment quality was investigated in a coal mining area (southern Brazil). Mine drainage showed pH between 3.2 and 4.6 and elevated concentrations of sulfate, As and metals, of which, Fe, Mn and Zn exceeded the limits for the emission of effluents stated in the Brazilian legislation. Arsenic also exceeded the limit, but only slightly. Groundwater monitoring wells from active mines and tailings piles showed pH interval and chemical concentrations similar to those of mine drainage. However, the river and ground water samples of municipal public water supplies revealed a pH range from 7.2 to 7.5 and low chemical concentrations, although Cd concentration slightly exceeded the limit adopted by Brazilian legislation for groundwater. In general, surface waters showed large pH range (6 to 10.8), and changes caused by acid drainage in the chemical composition of these waters were not very significant. Locally, acid drainage seemed to have dissolved carbonate rocks present in the local stratigraphic sequence, attenuating the dispersion of metals and As. Stream sediments presented anomalies of these elements, which were strongly dependent on the proximity of tailings piles and abandoned mines. We found that precipitation processes in sediments and the dilution of dissolved phases were responsible for the attenuation of the concentrations of the metals and As in the acid drainage and river water mixing zone. In general, a larger influence of mining activities on the chemical composition of the surface waters and sediments was observed when enrichment factors in relation to regional background levels were used.
Psychosocial factors associated with adherence to treatment and quality of life in people living with HIV/AIDS in Brazil
Authors: Calvetti Prisla Ücker , Giovelli Grazielly Rita Marques , Gauer Gabriel José Chittó , Moraes João Feliz Duarte de
Published: May 2014

Objective: The objective of this article was to investigate the biopsychosocial factors that influence adherence to treatment and the quality of life of individuals who have been successfully following the HIV/AIDS treatment. Methods: It is a cross-sectional study carried out with 120 HIV positive participants in the south of Brazil. Among the variables studied, of note are: perceived stress, social support, symptoms of anxiety and depression and quality of life. Results: The results show that a moderate to high adherence to the treatment paired with a strong sense of social support indicate a higher quality of life. Conclusion: The combination of social support and antiretroviral treatment have an impact on physical conditions, improving immune response and quality of life.
Psychiatric morbidity and quality of life of primary care attenders in two cities in Brazil
Authors: Portugal Flávia Batista , Campos Mônica Rodrigues , Gonçalves Daniel Almeida , Mari Jair de Jesus , Gask Linda , Bower Peter , Dowrick Christopher , Fortes Sandra
Published: May 2014

Objective: To identify the associations among quality of life (QoL), social determinants and psychological distress in primary care in two cities in Brazil. Methods: A cross-sectional study with 1,466 patients from 2009 to 2010. The statistical analysis used the t-test to compare the variables of interest to the study. Results: The prevalence of Common Mental Disorders (CMD3), severe forms of Common Mental Disorders (CMD5), anxiety and depression were 20.5%, 32%, 37% and 25.1% respectively. Thes presence of psychological distress is associated with worse QoL among the patients studied, especially those older than 40 years of age. In cases of CMD3, those with higher income and educational levels presented higher QoL in the psychical and psychological domains. For the cases of probable anxiety, those with higher educational levels presented lower scores on the physical and social relationship scores. Conclusion: Psychological distress can be associated with a worse QoL among those studied and can be influenced by socioeconomic conditions. Therefore, it is important to structure patient-centered help, which should also include patients’ social contexts.
Qualidade de vida e sintomas de ansiedade e depressão em pacientes com tumores cerebrais primários
Authors: Bigatão Marcela dos Reis , Carlotti Jr Carlos Gilberto , Carlo Marysia Mara Rodrigues do Prado de
Published: May 2014

Objetivo: Avaliar a qualidade de vida e sintomas de ansiedade e depressão em pacientes com diagnóstico de meningioma e glioma de alto grau submetidos à neurocirurgia oncológica. Métodos: Para a coleta de dados, foram aplicados dois instrumentos validados no Brasil: Hospital Anxiety and Depression Scale (HAD) e Item Short-Form Health Survey (SF-36). Resultados: Foram identificadas diferenças estatisticamente significativas quando comparados os dados do SF-36 de ambos os grupos tumorais, no pré e pós-operatório, nos aspectos: capacidade funcional (p = 0,043), aspecto emocional (p = 0,042) e saúde mental (p = 0,042) referente ao grupo meningioma. Quando comparados com respectivos grupos controle, houve diferenças significativas entre os grupos meningioma e controle, nos aspectos físico (p = 0,002) e emocional (p = 0,004), e entre os grupos glioma de alto grau e controle, nos aspectos capacidade funcional (p = 0,003) e físico (p = 0,003). Conclusão: A cirurgia oncológica gerou alterações de humor e na qualidade de vida em ambos os grupos, independente do tipo histológico do tumor. Apesar da relevância do tema, ainda são poucos os estudos sobre o tema.
Produção e composição do leite e escore corporal de cabras lactantes submetidas à suplementação mineral comercial e seletiva
Authors: Malafaia Pedro , Cruz Paula Barroso , Silva Vinícius Pimentel
Published: May 2014

A comparação da produção e composição do leite, do escore corporal e dos custos com a suplementação mineral comercial e seletiva foi feita utilizando-se dois grupos de 16 cabras lactantes por 164 dias. Não houve diferenças significativas na produção de leite dos animais que ingeriram os dois tipos de suplementos minerais. Não houve efeito do tipo de suplementação mineral em relação a composição do leite em gordura, proteína e lactose bem como na contagem de células somáticas (CCS). O consumo médio diário do suplemento comercial foi 1,76 vezes maior do que o suplemento contendo apenas cloreto de sódio associado ao sulfato de cobre. A utilização da mistura mineral seletiva, formulada com base no exame clínico-nutricional dos animais, gerou uma redução de aproximadamente 7 vezes o custo com a suplementação mineral do rebanho caprino.
Occurrence and molecular characterization of cryptococcosis in dogs and cats in Mato Grosso, Brazil
Authors: Paula Daphine A.J. de , Almeida Arleana B.P. F. de , Cruz Felipe S. da , Furlan Fernando H. , Colodel Edson M. , Sousa Valéria R.F. , Nakazato Luciano , Dutra Valéria
Published: May 2014

Cryptococcosis is an infection that affects humans and animals, the etiology is attributed to Cryptococcus neoformans variety neoformans, C. neoformans var. grubii and Cryptococcus gattii. The infection is common in dogs and cats, causing respiratory, neurological, cutaneous and ocular infections. Aiming to better understand the epidemiology of cryptococcosis in animals in the region, this paper describe the occurrence and characterization of the Cryptococcus species involved in this illness in pet animals at Mato Grosso State, Brazil. Clinical samples of four cases, two in cats and two dogs, were submitted for pathological, microbiological and molecular analysis. Microscopically, in three cases, tissue sections stained with hematoxylin and eosin had absence to severe granulomatous reaction composed by histiocytes, multinucleated cells and lymphocytes infiltration. In one case, citological imprint analysis showed similar inflammatory mainly mononuclear and lymphocyte cells infiltration. All cases had variable amounts of intracellular and extracellular fungal structures compatible with Cryptococcus sp. on Periodic Acid-Schiff (PAS) stain. All clinical samples were positive for culture on Sabouraud Dextrose Agar (SDA) and morphologically classified as Cryptococcus sp. The isolates were PCR positive for C. gatti, being confirmed by sequencing technique. The findings characterize the molecular species involved in animal infections in the region, and may contribute to future studies of the epidemiology of C. gattii.
Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho
Authors: Moreira Roberto , Dória Renata G.S. , Camargo Lázaro M. , Santos Marcelo D. , Minto Bruno W. , De Nardi Andrigo B. , Ambrósio Carlos E. , Freitas Silvio H.
Published: May 2014

Foi realizada falha segmentar com 6mm de diâmetro na região metafisária medial de tíbias de 12 coelhos, onde foi implantado uma associação de micro e macrofragmentos de matriz óssea cortical heteróloga fragmentada conservada em glicerina (98%) e polimetilmetacrilato autoclavados, para a sua reconstrução, e avaliados radiológica e macroscopicamente aos 30, 60, 90 e 120 dias. Houve adesão, em relação ao tempo, dos micro e macrocompósitos ao leito receptor, em 100% dos casos, mostrando ser biologicamente biocompatível, pois promoveram a reparação de falhas ósseas, sem sinais de infecção, migração e/ou rejeição, podendo, dessa forma, ser mais uma opção como substituto para preencher grandes defeitos ósseos.
Efeito de soluções eletrolíticas enterais com diferentes osmolaridades sobre o perfil eletrolítico e bioquímico de equinos
Authors: Ribeiro Filho José D. , Farias Sheila K. , Donner Athina C. , Oliveira Dyego P. , Guimarães José D. , Souza Maria V. , Gomes Cláudio L.N. , Avanza Marcel F.B.
Published: May 2014

Foram comparados os efeitos de soluções eletrolíticas com diferentes osmolaridades administradas via enteral por sonda nasoesofágica de pequeno calibre, em fluxo contínuo, sobre o perfil bioquímico em equinos. Foram utilizadas seis fêmeas adultas em dois quadrados latinos 6x3 simultâneos em modelo misto. Os animais foram distribuídos em três grupos e cada grupo submetido aos seguintes tratamentos: HipoMalt - 5g de cloreto de sódio, 0,5g de cloreto de potássio, 0,2g de pidolato de magnésio, 1g de gluconato de cálcio e 10g de maltodextrina diluídos em 1.000mL de água (181mOsmol L-1), HipoDext - 5g de cloreto de sódio, 0,5g de cloreto de potássio, 0,2g de pidolato de magnésio, 1g de gluconato de cálcio e 10g de dextrose diluídos em 1.000mL de água (228mOsmol L-1) e IsoProp - 5g de cloreto de sódio, 0,5g de cloreto de potássio, 0,2g de pidolato de magnésio e 10g de propionato de cálcio diluídos em 1.000mL de água (282mOsm L-1). As soluções contendo dextrose (HipoDext) e maltodextrina (HipoMalt) foram mais eficazes em aumentar a taxa glicêmica sem ocasionar desequilíbrio eletrolítico. Já o tratamento com propionato de cálcio (IsoProp) além de aumentar o lactato plasmático não teve efeito sobre a glicemia.
Problemas escolares e o consumo de álcool e outras drogas entre adolescentes
Authors: Cardoso Luciana Roberta Donola , Malbergier André
Published: May 2014

A relação entre problemas escolares e o uso de álcool, tabaco e drogas ilícitas em 965 adolescentes dos municípios de Jacareí e Diadema (SP) foi avaliada pelo instrumento de autopreenchimento Drug Use Screening Inventory. Este instrumento avalia o consumo de drogas e problemas a ele relacionados. O uso de substâncias foi associado a repetências, falta de concentração, notas baixas, desejo de abandonar a escola, sentir-se entediado no ambiente escolar, não fazer os deveres, faltar/chegar atrasado e prejuízos acadêmicos decorrentes do uso de drogas. A combinação do uso de álcool e tabaco foi associada a mais problemas escolares do que os encontrados em usuários exclusivos de álcool. Os problemas associados a esta combinação foram semelhantes aos observados em usuários de drogas ilícitas. Gostar da escola foi um fator protetor contra o uso de substâncias. Os resultados mostram a importância de se atentar para o relato de consumo das drogas lícitas combinadas.
Domesticated honey bees evolutionarily reduce flower nectar volume in a Tibetan lotus
Authors: Mu Junpeng , Peng Youhong , Xi Xinqiang , Wu Xinwei , Griffin John N. , Niklas Karl J. , Sun Shucun
Published: May 2014

Plants have evolved costly flowering traits, including the provisioning of rich nectar, to attract and reward their pollinators. Beekeeping (apiculture) locally increases densities of honey bees, which might drive economization of pollinator‐attracting traits, but the potential evolutionary consequences of beekeeping on plant–pollinator interactions remain unknown. Here, we present evidence suggesting that intensive apiculture has driven the rapid evolution of plant traits in the alpine lotus (Saussurea nigrescens) on the Tibetan Plateau by allowing reduced nectar volume provisioning without compromising pollination success. This conclusion is supported by measurements of reproductive and vegetative traits, including nectar, at sites of varying distance from apiaries that have housed introduced honey bees (Apis mellifera) since the early 1980s. Nectar volume was more than 60% lower at sites close to apiaries than at more distant sites, while nectar concentration remained consistent. When seedlings from field sites were grown under common garden conditions, trends in nectar volume identical to those in the field were observed, indicating that recently evolved genetic differences likely underlie patterns observed in the field. The adaptive advantage of reduced nectar volume under high pollinator density was clear in both the field and in the common garden. Specifically, plants from sites close to apiaries were taller, had more aboveground biomass, and produced more flowers and seeds compared to those at distant sites, which is consistent with the tradeoffs between nectar volume per flower and flower number per inflorescence within sites. The evolution of reduced nectar volume suggested by our results shows that the widespread practice of beekeeping might be a strong selective agent acting on wild plant populations and illustrates that human activities may indirectly affect evolution by changing critical species interactions.
Direct and indirect drivers of plant diversity responses to climate and clipping across northern temperate grassland
Authors: White Shannon R. , Bork Edward W. , Cahill James F.
Published: May 2014

It is well known that climate can influence plant community assembly via a multitude of indirect and direct pathways. However, interpretations of plant diversity responses to simulated climate change experiments, and subsequent predictions of plant communities under future climate scenarios, rarely address the importance of indirect effects. Networks of direct and indirect effects are also critical in understanding linkages between climate and grazing, a common land use of grasslands, and implications for plant diversity. We characterized the roles of indirect vs. direct effects in determining plant diversity responses to climate and grazing using data from three northern temperate grasslands in which we conducted factorial experiments manipulating precipitation, air temperature, and clipping intensity. Utilizing a structural equation modeling framework to address the multivariate networks, we found warming operated directly, causing species loss at all sites. We identified shoot biomass as the key indirect driver of diversity loss in response to both precipitation and clipping, regardless of site. However, site‐specific contingencies in the network of interactions were important for understanding varied precipitation effects. At the driest site only, shoot biomass was resistant to reduced precipitation, and diversity was consequently unaltered. Similarly, disconnect between primary drivers and responses explained relatively idiosyncratic responses of evenness compared to richness. Importantly, the finding of widespread, directly controlled plant diversity loss with warming aligns with concerns about declining biodiversity under climate change. However, using a framework of network interactions also allowed us to pinpoint the source of variability in response across systems. Looking forward, we can use the identification of this key indirect pathway to guide an understanding of community assembly under factors likely to control shoot biomass. Viewing a multifactorial, multisite experimental approach through a framework of network interactions allowed us to both identify generalized responses and distill the complexity of contingent responses. This, along with the practical need to identify diversity responses to climate change and grazing, underscores the importance of understanding both indirect and direct drivers of ecosystem responses to global change factors.
Limitations of extrapolating toxic effects on reproduction to the population level
Authors: Martin Benjamin , Jager Tjalling , Nisbet Roger M. , Preuss Thomas G. , Grimm Volker
Published: May 2014

For the ecological risk assessment of toxic chemicals, standardized tests on individuals are often used as proxies for population‐level effects. Here, we address the utility of one commonly used metric, reproductive output, as a proxy for population‐level effects. Because reproduction integrates the outcome of many interacting processes (e.g., feeding, growth, allocation of energy to reproduction), the observed toxic effects in a reproduction test could be due to stress on one of many processes. Although this makes reproduction a robust endpoint for detecting stress, it may mask important population‐level consequences if the different physiological processes stress affects are associated with different feedback mechanisms at the population level. We therefore evaluated how an observed reduction in reproduction found in a standard reproduction test translates to effects at the population level if it is caused by hypothetical toxicants affecting different physiological processes (physiological modes of action; PMoA). For this we used two consumer–resource models: the Yodzis‐Innes (YI) model, which is mathematically tractable, but requires strong assumptions of energetic equivalence among individuals as they progress through ontogeny, and an individual‐based implementation of dynamic energy budget theory (DEB‐IBM), which relaxes these assumptions at the expense of tractability. We identified two important feedback mechanisms controlling the link between individual‐ and population‐level stress in the YI model. These mechanisms turned out to also be important for interpreting some of the individual‐based model results; for two PMoAs, they determined the population response to stress in both models. In contrast, others stress types involved more complex feedbacks, because they asymmetrically stressed the production efficiency of reproduction and somatic growth. The feedbacks associated with different PMoAs drastically altered the link between individual‐ and population‐level effects. For example, hypothetical stressors with different PMoAs that had equal effects on reproduction had effects ranging from a negligible decline in biomass to population extinction. Thus, reproduction tests alone are of little use for extrapolating toxicity to the population level, but we showed that the ecological relevance of standard tests could easily be improved if growth is measured along with reproduction.
Divergence between phenotypic and genetic variation within populations of a common herb across Europe
Authors: Villellas Jesús , Berjano Regina , Terrab Anass , García María B.
Published: May 2014

Analyzing the pattern and causes of phenotypic and genetic variation within and among populations might help to understand life history variability in plants, and to predict their responses to changing environmental conditions. Here we compare phenotypic variation and genetic diversity of the widespread herb Plantago coronopus across Europe, and evaluate their relationship with environmental and geographical factors. Genetic diversity was estimated in 18 populations from molecular markers with AFLP. Phenotypic variation was measured in a subset of 11 populations on six life history traits (plant size, plant growth, fecundity, seed mass, mucilage production and ratio between two functionally different seed morphs). To account for ecological and geographical correlates, we estimated variability in local temperature, precipitation and intraspecific competition, and accounted for the central vs. peripheral position of populations. Phenotypic variation and genetic diversity were not significantly correlated within populations throughout the species' range. Phenotypic variation was positively linked to precipitation variability, whereas genetic diversity was correlated with the position of populations, suggesting that both types of variation are shaped by different processes. Precipitation seems to have acted as a selective agent for variation within populations in most life history traits, whereas the species' post‐glacial demographic history has likely reduced genetic diversity in northern peripheral populations with respect to central ones. The positive association between precipitation variability and phenotypic variation also suggests that plant populations may have higher adaptive potential in ecologically variable rather than stable environments. Our study offers an additional criterion when predicting the future performance of species under environmental changes.
The difference between killing and eating: ecological shortcomings of puma energetic models
Authors: Elbroch L. Mark , Allen Maximilian L. , Lowrey Blake H. , Wittmer Heiko U.
Published: May 2014

Bioenergetic modeling is employed to estimate the energetic demands of many cryptic carnivores and their kill rates needed to meet their energetic requirements. We tested two prevalent assumptions driving energetic modeling of predator kill rates: (1) morphological and physiological information (weight, energetic demands of activity patterns) of individual predators are sufficient to accurately predict their kill rates, and (2) kill and consumption rates are equivalent (meaning that carnivores consume all of what they kill). We did this by testing whether two independent energetic models accurately predicted puma (Puma concolor) kill and consumption rates in three study systems in North and South America with variable ecology, including climate and prey assemblages. Our results demonstrated that current puma energetic models drastically underestimate actual puma kill rates quantified through intensive field monitoring. We concluded that puma energetic models more realistically estimate puma consumption rates needed to meet metabolic requirements. Puma kill rates determined from field efforts were not explained by puma weight (in kg) or activity patterns (in distance traveled), which were the variables used in energetic models. Our kill rates in kg/day determined from field investigations of GPS clusters were the highest reported to date and statistically equivalent across three distinct ecosystems, a range of puma characteristics, variable lengths of monitoring, variable daily distances traveled, and across systems with 1–3 ungulate prey. In contrast, puma kill rates in ungulates/week differed across study areas, suggesting that kill rates described in kilograms per day are better suited for comparing puma kill rates across systems while kill rates in terms of ungulates per unit time are better suited for modeling predator‐prey dynamics for a particular ecosystem. Based on these results we concluded that energetic models using morphological and physiological variables alone were insufficient to predict kill rates, and proposed that rather than focusing future research on refining current energetic models, future research should be directed at understanding the behavioral ecology driving carnivore kill rates.
A Metabolic–Epidemiological Microsimulation Model to Estimate the Changes in Energy Intake and Physical Activity Necessary to Meet the Healthy People 2020 Obesity Objective
Authors: Basu Sanjay , Seligman Hilary , Winkleby Marilyn
Published: May 2014

Objectives. We combined a metabolic and an epidemiological model of obesity to estimate changes in calorie intake and physical activity necessary to achieve the Healthy People 2020 objective of reducing adult obesity prevalence from 33.9% to 30.5%.

Methods. We used the National Health and Nutrition Examination Survey (1999–2010) to construct and validate a microsimulation model of the US population aged 10 years and older, for 2010 to 2020.

Results. Obesity prevalence is expected to shift toward older adults, and disparities are expected to widen between White, higher-income groups and minority, lower-income groups if recent calorie consumption and expenditure trends continue into the future. Although a less than 10% reduction in daily calorie intake or increase in physical activity would in theory achieve the Healthy People 2020 objective, no single population-level intervention is likely to achieve the target alone, and individual weight-loss attempts are even more unlikely to achieve the target.

Conclusions. Changes in calorie intake and physical activity portend rising inequalities in obesity prevalence. These changes require multiple simultaneous population interventions.
Using Social Network Analysis to Clarify the Role of Obesity in Selection of Adolescent Friends
Authors: Schaefer David R. , Simpkins Sandra D.
Published: May 2014

Objectives. We used social network analysis to examine how weight status affects friend selection, with an emphasis on homophily and the social marginalization of overweight youths.

Methods. We used an exponential random graph model to assess the effects of body mass index (BMI) on friend selection while controlling for several alternative selection processes. Data were derived from 58 987 students in 88 US middle and high schools who took part in the 1994 to 1996 National Longitudinal Study of Adolescent Health.

Results. On average, overweight youths were less likely than nonoverweight youths to be selected as a friend; however, this effect differed according to the BMI of the person initiating the friendship. Nonoverweight youths were 30% more likely to select a nonoverweight friend than an overweight friend, whereas overweight youths were largely indifferent to the weight status of their friends. Friendship ties from overweight youths to nonoverweight peers were more likely than ties in the reverse direction.

Conclusions. We found evidence consistent with homophily and social marginalization but only for the selection behavior of nonoverweight youths. We conclude that avoidance of overweight friends is the primary determinant of friendship patterns related to BMI.