bluuebunny/crossref_metadata_2025_split huggingface dataset:
Affective and motivational factors of learning in online mathematics courses
Authors: Kim ChanMin , Park Seung Won , Cozart Joe 
Published: December 2012

AbstractWe investigated what factors would be related to students' achievement in mathematics courses offered at a virtual high school. This was an attempt to understand why some succeed and some do not as well as to suggest what should be done to help with student success. Seventy‐two students responded to a self‐report survey on motivation (ie, self‐efficacy, intrinsic value), mathematics achievement emotions (ie, anxiety, anger, shame, hopelessness, boredom, enjoyment, pride), and cognitive processes (ie, cognitive strategy use, self‐regulation). A three‐step hierarchical multivariate regression was employed to examine which of the factors predict student achievement. Results showed that motivation accounted for approximately 13% of the variance in student achievement and self‐efficacy was the significant individual predictor of student achievement. However, when achievement emotions were added to the analysis, self‐efficacy failed to predict student achievement and emotions accounted for 37% of the variance in student achievement. Cognitive strategy use and self‐regulation did not explain any additional variance in the final scores. Findings are discussed and implications for future research and development are also suggested.
What Do Healthcare Workers Know About Sudden Infant Death Syndrome?: The Results of the Italian Campaign ‘GenitoriPiù’
Authors: de Luca Federico , Boccuzzo Giovanna 
Published: December 2012

SummaryThe paper analyses the data resulting from the Italian campaign for newborns’ parents, ‘GenitoriPiù’, and focuses on the assessment of healthcare workers’ knowledge about sudden infant death syndrome. Considering two different response sets (dichotomous and polytomous), we used a Rasch model and a logistic quantile regression to analyse which demographic and professional backgrounds influenced the degree of knowledge of this topic. Significant differences between regions are evident, and the effect of training initiatives is proven as a way of rectifying these differences. With regard to professional background, the best-prepared healthcare workers are paediatricians and healthcare workers working in birth centres and family planning clinics.
Antithetic Time Series Analysis and the Companyx Data
Authors: Ridley Dennis , Ngnepieba Pierre 
Published: December 2012

SummaryAntithetic time series analysis is the solution to a most perplexing problem in mathematical statistics. When a mathematical model is fitted to serially correlated data, the parameters of the model are unavoidably biased. All forecasts that are obtained from the model are unavoidably biased and therefore diverge. The forecast reliability worsens with the forecast horizon. It is shown that the forecast bias can be dynamically reduced. This is made possible by the entirely counterintuitive discovery of antithetic time series theory that permits unbiased forecast error convergence to a constant, independent of forecast origin. The forecast error variance in each time period is the same.
THE EFFECT OF MONETARY POLICY ON CREDIT SPREADS
Authors: Cenesizoglu Tolga , Essid Badye 
Published: December 2012

AbstractWe analyze the effect of monetary policy on yield spreads between corporate bonds with different credit ratings over the business cycle. We use futures contracts to distinguish between expected and unexpected changes in the Fed funds target rate and several indicators to distinguish between different phases of the business cycle. In line with the predictions of imperfect capital market theories, we find that yields on corporate bonds with low credit ratings widen (narrow) with respect to those with high credit ratings following an unexpected increase (decrease) in the Fed funds target rate during recession periods. Several tests suggest that our results are robust to outliers, potential endogeneity problems, empirical specification, control variables, countercyclical risk premium in futures, and alternative definitions of credit spreads and economic conditions.
Validity of Survey Response Propensity Indicators: A Behavior Genetics Approach
Authors: Littvay Levente , Popa Sebastian Adrian , Fazekas Zoltán 
Published: December 2012

ObjectivesThis study explains how behavior genetic analysis using a twin design can help us assess the validity of our measures.MethodsWe test multiple indicators of response propensity, a measure used by survey researchers to better understand the similarities and differences between survey respondents and nonrespondents. The response propensity indicators evaluated include response to follow‐up surveys and subsequent waves of a panel and the completion of a sensitive recontact information sheet to aid subsequent recontact efforts.ResultsA classical and the newly proposed method of validation all point to insufficient validity of our response propensity measures. Construct validation using data from the National Survey of Midlife Development in the United States exhibited little correlation between indicators. Genetic analysis suggests that the success of subsequent data‐collection efforts is predominantly driven by additive genetic effects, while nonresponse to inquiries for recontact information is influenced predominantly by familial environmental predictors.ConclusionOur results indicate that different underlying constructs drive the response propensity indicators, suggesting that nonresponse is, at minimum, multidimensional.
Corruption or Insecurity? Understanding Dissatisfaction with Mexico’s Police
Authors: Sabet Daniel M. 
Published: December 2012

AbstractSince at least 2005, Mexico has confronted a severe security crisis that threatens to undermine its rule of law and democracy. An effective police response has been hindered by frustrated citizens who do not report crime, come forward with information, serve as witnesses, or support their police. This foments a vicious cycle whereby insecurity and corruption foster dissatisfaction, which yields further insecurity and corruption. Breaking this cycle requires a better understanding of why citizens are dissatisfied with their police. One view holds that discontent is due to police corruption, but a somewhat rival perspective contends that citizens are primarily concerned with security outcomes. This study uses comparative survey data from 14 major Mexican cities to test these potentially rival approaches. It finds that both corruption and security outcomes matter, but direct experience with bribery has the single largest impact on dissatisfaction with the police.
Getting to Yes or Bailing on No: The Site Selection Process of Ethanol Plants in Wisconsin
Authors: Tigges Leann M. , Noble Molly 
Published: December 2012

AbstractPrior studies of ethanol location rest on the assumption that ethanol producers are economic free agents—evaluating sites as if all counties are contenders for their business, weighing the availability of feedstocks along with their infrastructure needs, operating without ties to localities, and being subject to enticement from policy incentives. We analyze the political‐economic process through which ethanol plants come into communities by examining plant location decisions, plant financing, community receptivity toward the plant, local government incentives, and the dynamics of the approval process. We use case studies of ethanol plants in Wisconsin to explore the economic, social, and political dynamics of ethanol plant location. Our case studies provide evidence in support of some findings in the ethanol location literature—such as the importance of access to corn; however, they also suggest site selection criteria not adequately addressed by the literature. Furthermore, our data suggest that capital may not be as mobile as location theory assumes it to be and that location decisions are not primarily determined by consideration of profit maximization. Instead, the location of ethanol plants is greatly influenced by the extent to which the original initiators of the plant are locally embedded in its host community. Our research answers Barkley and McNamara's (:45) call for a return to a case studies approach in order to develop “reliable insights into the location process.”
Telocytes in the human kidney cortex
Authors: Qi Guisheng , Lin Miao , Xu Ming , Manole C. G. , Wang Xiangdong , Zhu Tongyu 
Published: December 2012

AbstractRenal interstitial cells play an important role in the physiology and pathology of the kidneys. As a novel type of interstitial cell, telocytes (TCs) have been described in various tissues and organs, including the heart, lung, skeletal muscle, urinary tract, etc. (www.telocytes.com). However, it is not known if TCs are present in the kidney interstitium. We demonstrated the presence of TCs in human kidney cortex interstitium using primary cell culture, transmission electron microscopy (TEM) and in situ immunohistochemistry (IHC). Renal TCs were positive for CD34, CD117 and vimentin. They were localized in the kidney cortex interstitial compartment, partially covering the tubules and vascular walls. Morphologically, renal TCs resemble TCs described in other organs, with very long telopodes (Tps) composed of thin segments (podomers) and dilated segments (podoms). However, their possible roles (beyond intercellular signalling) as well as their specific phenotype in the kidney remain to be established.
Stability of Anthocyanin‐Rich W/O/W‐Emulsions Designed for Intestinal Release in Gastrointestinal Environment
Authors: Frank Kerstin , Walz Elke , Gräf Volker , Greiner Ralf , Köhler Karsten , Schuchmann Heike Petra 
Published: December 2012

Abstract:  Anthocyanins belong to the most important hydrophilic plant pigments. Outside their natural environment, these molecules are extremely unstable. Encapsulating them in submicron‐sized containers is one possibility to stabilize them for the use in bioactivity studies or functional foods. The containers have to be designed for a target release in the human gastrointestinal system. In this contribution, an anthocyanin‐rich bilberry extract was encapsulated in the inner aqueous phase of water‐in‐oil‐in‐water‐double emulsions. The physical stability as well as the release of free fatty acids and encapsulated, bioactive substances from the emulsions during an in vitro gastrointestinal passage were investigated. The focus was on the influence of emulsion microstructural parameters (for example, inner and outer droplet size, disperse phase content) and required additives (emulsifier systems), respectively. It could be shown that it is possible to stabilize anthocyanins in the inner phase of double emulsions. The release rate of free fatty acids during incubation was independent of the emulsifier used. However, the exterior (O/W)‐emulsifier has an impact on the stability of multiple emulsions in gastrointestinal environment and, thus, the location of release. Long‐chained emulsifiers like whey proteins are most suitable to transport a maximum amount of bioactive substances to the effective location, being the small intestine for anthocyanins. In addition, it was shown that the dominating release mechanism for entrapped matter was coalescence of the interior W1‐droplets with the surrounding W2‐phase.Practical Application:  Microencapsulation of phytochemicals and bioactives is in the focus of functional food development. Here, the influence of matrix material, formulation, and structural parameters on stabilization and release of the molecules encapsulated has to be known for target product and process design. As the results are representative for hydrophilic active ingredients encapsulated in double emulsion systems a cross‐sectoral use in the pharmaceutical sector is possible.
Phylogenetic position of Kontumia (Polypodiaceae) inferred from four chloroplast DNA regions
Authors: KIM Changkyun , ZHA Hong‐Guang , DENG Tao , SUN Hang , WU Su‐Gong 
Published: December 2012

AbstractThe phylogenetic position of the monotypic genus Kontumia (Polypodiaceae) is contentious. It has been suggested that Kontumia is related to Gymnogrammitis dareiformis (Drynarioideae) based on spore ornamentation and blade dissection, or it has been assigned as a member of microsoroid ferns (Microsoroideae) based on the shape of rhizome scales. In the present study, we determined the phylogenetic position of K. heterophylla using four chloroplast DNA regions (rbcL, atpB, rps4 + rps4‐trnS intergenic spacer [IGS], and trnL‐F IGS). A parsimony consensus tree indicated that K. heterophylla is not related to G. dareiformis, but is nested within the Leptochilus lineage of Microsoroideae. This relationship is also supported by sharing of clathrate scales on the rhizome, which is not found in G. dareiformis. Although marked morphological disparities are found between K. heterophylla and the Leptochilus lineage in terms of leaf dissection, fertile‐sterile leaf differentiation, and sori arrangement, our results indicate that these characters have evolved independently several times in Polypodiaceae.
Error propagation in biomass estimation in tropical forests
Authors: Molto Quentin , Rossi Vivien , Blanc Lilian 
Published: December 2012

SummaryReliable above‐ground biomass (AGB) estimates are required for studies of carbon fluxes and stocks. However, there is a huge lack of knowledge concerning the precision ofAGBestimates and the sources of this uncertainty. At the tree level, the tree height is predicted using the tree diameter at breast height (DBH) and a height sub‐model. The wood‐specific gravity (WSG) is predicted with taxonomic information and aWSGsub‐model. The tree mass is predicted using the predicted height, the predictedWSGand the biomass sub‐model.Our models were inferred with Bayesian methods and the uncertainty propagated with a Monte Carlo scheme. The uncertainties in the predictions of tree height, treeWSGand tree mass were neglected sequentially to quantify their contributions to the uncertainty inAGB. The study was conducted in French Guiana where long‐term research on forest ecosystems provided an outstanding data collection on tree height, tree dynamics, tree mass and speciesWSG.We found that the uncertainty in theAGBestimates was found to derive primarily from the biomass sub‐model. The models used to predict the tree heights andWSGcontributed negligible uncertainty to the final estimate.Considering our results, a poor knowledge ofWSGand the height–diameter relationship does not increase the uncertainty inAGBestimates. However, it could lead to bias. Therefore, models and databases should be used with care.This study provides a methodological framework that can be broadly used by foresters and plant ecologist. It provides the accurate confidence intervals associated with forestAGBestimates made from inventory data. When estimating region‐scaleAGBvalues (through spatial interpolation, spatial modelling or satellite signal treatment), the uncertainty of the forestAGBvalue in the reference forest plots has to be taken in account. We believe that in the light of the Reducing Emissions from Deforestation and Degradation debate, our method is a crucial step in monitoring carbon stocks and their spatio‐temporal evolution.
Understanding the relationship between dog ownership and children's physical activity and sedentary behaviour
Authors: Christian H. , Trapp G. , Lauritsen C. , Wright K. , Giles‐Corti B. 
Published: December 2012

SummaryWhat is already known about this subject
Dog ownership is a catalyst for physical activity in adults.
Approximately 50–70% of Australian households with children have a dog.
Dog‐facilitated physical activity may be an effective way to increase physical activity and decrease child overweight and obesity.
What this study adds
Dog ownership was associated with self‐reported walking and physical activity, but not parent‐report screen use or measured weight status.
The results highlight the potential for dog ownership to significantly impact children's physical activity levels.
Within dog‐owning families, the promotion of walking and active play with a dog may be a strategy to increase children's physical activity and curb obesity.
BackgroundDog ownership is a catalyst for physical activity in adults. Given 50–70% of Australian households with children have a dog, dog‐facilitated physical activity may be an effective way to increase physical activity and decrease child obesity.ObjectiveWe hypothesized that children with a family dog walk more, are more physically active and are more likely to achieve recommended levels of weekly physical activity compared with children who do not have a dog.MethodCross‐sectional data from the Western Australian TRravel, Environment, and Kids project (TREK) were analyzed for 1218 children aged 10–12 years. Individual and environment factors, child physical activity, walking, screen use, sedentary behaviour and dog ownership status was collected from child and parent questionnaires. Children's height and weight were measured.ResultsApproximately 60% of children had a family dog. Dog ownership was associated with, on average, 29 more minutes of walking and 142 more minutes of physical activity per week (P ≤ 0.01). After adjustment, children with a dog were 49% more likely to achieve the recommended level of weekly physical activity (420 min) and 32% more likely to have walked in their neighbourhood in the last week, compared with non‐dog owners (P ≤ 0.05). These relationships varied by gender. Dog ownership was not associated with screen use or weight status.ConclusionsDog ownership was associated with walking and physical activity, but not screen use or weight status. Within dog‐owning families, the promotion of walking and active play with a dog may be a strategy to increase children's physical activity.
The association between community‐level economic hardship and childhood obesity prevalence in Los Angeles
Authors: Shih M. , Dumke K. A. , Goran M. I. , Simon P. A. 
Published: December 2012

Summary
What is already known about this subject
Neighbourhood social, economic and environmental factors are associated with childhood obesity.
Childhood obesity disproportionately impacts those living in low‐income neighbourhoods.

What this study adds
Childhood obesity prevalence is strongly associated with community‐level social and economic conditions as measured using a composite Economic Hardship Index.
Childhood obesity prevalence among communities in the highest hardship quartile was more than double the prevalence among communities in the lowest hardship quartile (26.9 vs. 12.5%).
The relationship between economic hardship and obesity differs by race/ethnicity.
ObjectiveThe association between community‐level economic hardship and childhood obesity prevalence was examined in Los Angeles County, one of the largest and most racially and ethnically diverse regions in the United States.MethodsData from the 2008–2009 California Department of Education's Physical Fitness Testing Program were analyzed to assess obesity prevalence among 5th, 7th and 9th grade students attending public schools (n = 298 485). Community‐level socioeconomic conditions were compared using a census‐tract‐based Economic Hardship (EH) index. Mixed‐effects modelling was used to examine the association between obesity prevalence and gender, grade, race/ethnicity and EH.ResultsHigher community‐level EH was associated with higher childhood obesity prevalence (P < 0.001). The obesity prevalence among communities in the highest EH quartile (26.9%) was more than double the obesity prevalence among communities in the lowest EH quartile (12.5%). The slope of the association between EH and childhood obesity differed by racial/ethnic group. The slope was higher for non‐Hispanic White students, Hispanics, and non‐Hispanic Asians, and lower for non‐Hispanic Black students. Racial/ethnic disparities were observed across the socioeconomic spectrum.ConclusionsFindings suggest that efforts to improve community socioeconomic conditions could reduce childhood obesity prevalence. Prevention efforts should target communities with high economic hardship and also focus on providing culturally relevant interventions that address disparities in obesity prevalence across communities.
No association between childcare and obesity at age 4 in low‐income Latino children
Authors: Zahir N. , Heyman M. B. , Wojcicki J. M. 
Published: December 2012

SummaryBackgroundPrevious studies have found an association between early entry to childcare and risk for overweight and obesity at 3 years of age. These studies, however, have been conducted primarily with higher income White populations or have found increased risk in the children of educated mothers.ObjectiveTo assess the relationship between timing of entry to childcare and duration of childcare and pediatric overweight and obesity in a high risk population.MethodsUsing data from a longitudinal cohort of low‐income Latino children in San Francisco, we evaluated the association between time of entry to childcare, hours in childcare, and risk for overweight and obesity at age 4. Similarly, we evaluated the relationship between these same childcare parameters and body mass index Z score and risk of having a waist circumference (WC) percentile ≥90th at 4 years of age.ResultsIn contrast with previous studies, we found no association between being in childcare at 4 years of age or number of hours per week in childcare and risk for childhood overweight, obesity or WC ≥90th percentile at age 4. Additionally, we found no association between age of entry to childcare (≤6 months or ≤12 months of age) with risk for overweight or obesity at age 4. Future studies need to further evaluate the differential impact of childcare on early childhood obesity in relation to race/ethnicity and lower socioeconomic status.ConclusionLow‐income children may not be at increased risk for obesity in relation to early childcare exposure.
Effects of Tm3+ Additions on the Crystallization of LaF3 Nanocrystals in Oxyfluoride Glasses: Optical Characterization and Up‐Conversion
Authors: de Pablos‐Martín A. , Ristic D. , Bhattacharyya S. , Höche Th. , Mather G.C. , O Ramírez M. , Soria S. , Ferrari M. , Righini G.C. , Bausá L.E. , Durán A. , Pascual M.J. 
Published: December 2012

The influence of the addition of 1 mol% Tm2O3 on the nanocrystallization of LaF3 in a glass of composition 55SiO2–20Al2O3–15Na2O–10LaF3 (mol%) has been studied. Tm2O3 affects the phase separation in the glass and delays the onset of crystallization with respect to the undoped glass. Additionally, the maximum LaF3 crystal size is slightly greater than that in the undoped glass–ceramics. The microstructural and compositional changes in the glass matrix have been studied using several techniques, including viscosity, dilatometry, X‐ray and neutron diffraction (XRD, ND), quantitative Rietveld refinement, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and Raman spectroscopy. Photoluminescence measurements indicate that the Tm3+ ions are distributed between the glassy matrix and LaF3 crystals. Eu2O3 has been used as structure probe and part of the Eu3+ ions are reduced to Eu2+ when incorporated in the LaF3 nano‐crystals. Up‐conversion spectra under IR‐excitation show a higher intensity of the blue emission in the Tm‐doped glass–ceramic compared with that in the glass.