203,592 research outputs found
Upper Missouri Waterkeeper v. EPA
State water quality standards developed under the Clean Water Act play a key role in curtailing the negative environmental, economic, and human health impacts of water pollution. Under the state water quality regulatory framework, EPA may grant variances to state standards should the state demonstrate the compliance with its standards is infeasible for a certain pollutant discharger or waterbody. Montana DEQ developed a variance for nutrients based on evidence that compliance with those standards would cause economic harm. EPA approved Montana\u27s nutrient pollutant variance, and Upper Missouri Waterkeeper challenged EPA\u27s approval on the grounds that the variance violates the Clean Water Act. The Ninth Circuit held that (1) EPA may consider the cost of implementing pollution control technology to attain compliance with state standards when approving variance requests, and (2) EPA properly interpreted its regulations as requiring compliance with the variance standard only at the end of the variance term. This note will explore how the decision may incentivize states to engage in a water quality race-to-the-bottom, sacrificing improvements in the name of cost, failing to protect the health of our nation\u27s waters, and further exposing low-income communities to degraded resources
A comparison of the effect of logistic strategy and logistics integration on firm competitiveness in the USA and China
Purpose â The purpose of this manuscript is to empirically compare logistics strategies in Chinese and US manufacturing firms and the outcomes of these strategies to test the underlying factor structure and measurement equivalences of Bowersox/Daugherty model and its relationship with critical success factors. Design/methodology/approach â A structured questionnaire was used to gather data fromChinese and American logistics managers. Using confirmatory factor analysis (CFA), the authorscompared the three dimensions of the overall logistics strategy (OLS) â process strategy, market strategy, and information strategy â in two countries. A structural equation model (SEM) was then used to assess the impact of OLS on perceived competitiveness in two countries.Findings â Although the economic, political, and cultural dimensions of the two countries differed substantially, the findings were similar. Data from both countries provided strong support for the three dimensions of overall logistic strategy (OLS). In addition, it was found that OLS, when combined with logistics coordination effectiveness (LCE) and customer service effectiveness (CSE), contributes to organizational effectiveness (COMP).Practical implications â This research provides insights into comparative logistics in two large disparate economies and provides support for the Bowersox/Daugherty logistics/supply chainmanagement typology.Originality/value â This manuscript provides insights into comparative logistics/supply chain management that have not been previously reported through empirical research
KAJIAN TENTANG PENGARUH TWO STAGE CLUSTER SAMPLING TERHADAP STATISTIK UJI-F
In regression analysis we make several assumptions about the error term. The following assumptions are often made: 1) the error terms are random variables with mean 0; 2) nonautocorrelation; 3) homoscedasticity, and 4) normality. The assumption of identically and independently distributed (iid) observations that underlies regression procedures is called into question when analyzing complex survey data. Particularly the existence of clusters in two stage samples usually exhibit positive intracluster correlation. If we use Ordinary Least Squares (OLS) procedures to make inferences in regression analysis for two stage cluster samples, we will be faced with a problem. This study aims to know the effect of two stage least squares on the F-Statistic. In general, although OLS procedures are unbiased but not fully efficient for estimation of the regression coefficients. Variance of the OLS estimators for the regression coefficients can be larger than the usual OLS variance expression would indicate. Failure to consider this possibility leads to underestimation of variances, with consequences for confidence intervals and the F-Statistic. The effect of intracluster correlation on the F-Statistic is the distortion of its distribution. The F-Statistic will not follow the Central F distribution anymore. Consequently, the hypothesis testing procedure is invalid
Les tĂ©lĂ©connexions de croissance comme indicateurs des impacts des changements climatiques sur les Ă©cosystĂšmes forestiers : Le cas des forĂȘts borĂ©ales de la rĂ©gion de lâatlantique nord.
Depuis la fin du 20e siĂšcle, dâimportantes baisses de croissance et de nombreuses baisses de corrĂ©lation entre croissance et tempĂ©ratures estivales ont Ă©tĂ© observĂ©es dans plusieurs rĂ©gions borĂ©ales. Lâorigine de tels changements, bien que variable dâune rĂ©gion Ă une autre, a souvent Ă©tĂ© expliquĂ©e par des Ă©tĂ©s de plus en plus chauds et secs qui forcent les arbres Ă fermer leurs stomates afin dâĂ©viter de trop importantes pertes dâeau par transpiration. La disponibilitĂ© en eau et la respiration semblent donc avoir un contrĂŽle grandissant sur les processus de croissance face au rĂ©chauffement climatique. A lâĂ©chelle dâun peuplement forestier, lâattribution de ces changements de croissance aux seuls effets des changements climatiques reste cependant difficile car de nombreuses et complexes interactions existent entre le climat, les processus physiologiques de croissance et les facteurs de site (topographie, type de sol, etc.). En revanche, lâapparition de synchronisations de croissance de peuplements gĂ©ographiquement Ă©loignĂ©s prĂ©sentant des caractĂ©ristiques pĂ©dologiques et bioclimatiques diffĂ©rentes, traduit de maniĂšre plus certaine un forçage climatique de large Ă©chelle sur la croissance, tels que ceux induits par les changements climatiques.
Cette thĂšse a pour objectifs de tester si (1) le rĂ©chauffement climatique homogĂ©nĂ©ise la croissance des arbres et leurs rĂ©ponses au climat sur de larges Ă©chelles et si (2) les variations observĂ©es dans les corrĂ©lations entre la croissance et les tempĂ©ratures estivales Ă©manent dâun contrĂŽle de plus en plus important des facteurs hydrauliques sur la croissance. Contrairement aux Ă©tudes prĂ©cĂ©dentes, elle sâappuie sur une mĂ©thode novatrice : lâapparition de tĂ©lĂ©connexions dans les patrons de croissance comme indicateur des impacts du rĂ©chauffement climatique sur les dynamiques de croissance. Elle compare la croissance des forĂȘts borĂ©ales du QuĂ©bec (50°N-52°N, 58°W-82°W) et de la SuĂšde (59°N-68°N, 12°E-24°E), deux rĂ©gions sĂ©parĂ©es par lâOcĂ©an Atlantique, et au climat fortement contrĂŽlĂ© par les dynamiques ocĂ©aniques et climatiques nord-atlantiques. Lâensemble des hypothĂšses est testĂ© Ă diffĂ©rentes Ă©chelles spatiales et temporelles en comparant des donnĂ©es de croissance provenant Ă la fois de larges bases de donnĂ©es dâinventaires (103-104 arbres Ă©chantillonnĂ©s) et de modĂ©lisation forestiĂšre.
Dans un premier chapitre, cette thĂšse Ă©tudie la frĂ©quence et lâorigine climatique dâanomalies de croissance interannuelles et multi-dĂ©cennales Ă travers le QuĂ©bec borĂ©al de 1901 Ă 2001. Lâorigine climatique de chaque type dâanomalie est Ă©tudiĂ©e par analyses dâĂ©poques superposĂ©es en incluant des facteurs climatiques locaux (tempĂ©ratures et prĂ©cipitation mensuelles) et globaux (Oscillations Nord Atlantique/ONA et Oscillation Arctique/OA). Dans un deuxiĂšme chapitre, cette thĂšse analyse les impacts des dynamiques nord-atlantiques post-1950 sur la croissance des forĂȘts borĂ©ales du QuĂ©bec et de la SuĂšde en Ă©tudiant les tĂ©lĂ©connexions de croissance entre ces deux rĂ©gions, et leurs rĂ©ponses Ă certains indices climatiques nord-atlantiques (ex. ONA et OA) et aux tempĂ©ratures saisonniĂšres. Dans un troisiĂšme et dernier chapitre, cette thĂšse explore si le renforcement prĂ©vu des contraintes hydrauliques sur la croissance des forĂȘts borĂ©ales du QuĂ©bec peut ĂȘtre dĂ©tectĂ© par une instabilitĂ© des relations climat-croissance (observĂ©e et simulĂ©e) entre 1908 et 2013. Les donnĂ©es de croissance observĂ©e proviennent de rĂ©cents inventaires forestiers et les donnĂ©es de croissance simulĂ©e sont obtenues Ă lâaide dâun modĂšle bioclimatique de croissance des peuplements basĂ© sur des processus physiologiques. La corrĂ©lation au cours du temps entre les donnĂ©es observĂ©es et simulĂ©es, ainsi que leurs rĂ©ponses respectives au climat mensuel (tempĂ©ratures minimum et maximum, prĂ©cipitations totales), sont Ă©tudiĂ©es par corrĂ©lations mobiles.
La synthĂšse transversale des trois chapitres indique que lâhomogĂ©nĂ©isation des dynamiques de croissance des forĂȘts borĂ©ales de la rĂ©gion de lâAtlantique Nord au cours du 20e siĂšcle nâa Ă©tĂ© que partielle. Elle sâest manifestĂ©e par deux phĂ©nomĂšnes seulement : (1) une augmentation de la frĂ©quence des annĂ©es Ă faible croissance entre le dĂ©but et la fin du siĂšcle au QuĂ©bec, et (2) une baisse de corrĂ©lation entre croissance et tempĂ©ratures estivales dans de nombreux peuplements de cette mĂȘme rĂ©gion au milieu du siĂšcle. Si le premier phĂ©nomĂšne semble associĂ© au rĂ©chauffement climatique, le deuxiĂšme semble Ă©maner de causes diverses telles quâune respiration plus importante ou une diminution du couvert neigeux hivernal. Face Ă un rĂ©chauffement climatique gĂ©nĂ©ralisĂ© (dans le temps et lâespace), lâhĂ©tĂ©rogĂ©nĂ©itĂ© des dynamiques suggĂšre une importance grandissante (i) du climat de lâannĂ©e prĂ©cĂ©dente et de dormance sur la respiration de maintenance, (ii) des facteurs locaux, et particuliĂšrement pĂ©dologiques et topographiques, dans la modulation de la croissance et (iii) de la variabilitĂ© spatiotemporelle des prĂ©cipitations. Cette Ă©tude montre que la complexitĂ© des liens existants entre variabilitĂ© climatique et croissance est encore trop importante pour pouvoir prĂ©dire avec prĂ©cision lâimpact des changements climatiques futurs sur les Ă©cosystĂšmes forestiers
Reliability of a food menu to measure energy and macronutrient intake in adolescents
Background/Objectives: The aim of this study was to evaluate the reliability of a food menu to measure energy and macronutrient intake within the laboratory and under real-life conditions in adolescents. Subjects/Methods: A total of 12 boys and 8 girls (age 14.3 (s.d. 2.4) years, body mass index (BMI) 20.8 (s.d. 4.0)?kg/m2) completed two identical in-laboratory sessions (ILS) and two out-of-laboratory sessions (OLS). During the ILS, participants had ad libitum access to a variety of foods (74 items in total), which they chose from a menu every hour, for 5?h (0800â1300?h). For the OLS (1300?h until bedtime), the foods were chosen from the same menu at 1300?h and packed into containers to bring home with them. Results: Testâretest analysis of energy and macronutrient intake revealed no significant differences (ILS and OLS). Intra-class correlations ranged between 0.69 and 0.83 (ILS) and between 0.48 and 0.73 (OLS) for energy and macronutrient intake (all P<0.01). Within-subject coefficients of variation ranged between 12.9% and 23.5% for the ILS and between 24.0% and 37.7% for the OLS. BlandâAltman plots showed acceptable agreement. Finally, the food menu was well appreciated by the participants with a 75% appreciation rate on a visual analog scale. Conclusions: This food menu provides a reasonably reliable measure of energy and macronutrient intake in adolescents, irrespective of sex and BMI, especially inside the laboratory setting. Despite the difficulties in capturing a stable measure of energy intake in research, this tool could be a useful addition to the methods currently used to assess ad libitum food intake in youth
Retention of stumps on wet ground at stump-harvest and its effects on saproxylic insects
Low stumps represent on their own up to 80% of the dead wood remaining on clear cuts and therefore supply suitable habitat for saproxylic insects i.e. insects depending on dead wood for their survival. Recent stump harvesting activities threaten this substrate of ecological importance and increase the anthropogenic negative impacts on these species. Because of technical and environmental reasons (nutrient leakage, erosion) guidelines for stump harvesting recommend to retain stumps standing in wet parts of clear cuts. However, stumps in wet positions might not be a satisfactory substrate for saproxylic insects and therefore might not be as much used as stumps in dry positions. To test this hypothesis, a total of 100 stumps (50 spruces and 50 birches) were collected on four clear cuts between 5 and 7 years old near Uppsala, Sweden. Stump samples were paired to get a balanced dataset, each pair containing two stumps of the same tree species, diameter and sun-exposure, one dry and one wet. Each sample was placed in a rearing box for 2 months. All emerging insects were sorted out down to order, family, genus or species level according to their importance in the project. Species richness, abundance and composition in each type of stumps were analyzed. Proportion of stumps inhabited, density and Shannonâs diversity and evenness were calculated for each insect order. A canonical correspondence analysis was performed to investigate the possible connections existing between insect species and the tree species and dryness of the stumps. In total, 17065 insects were collected representing 114 species out of which 96 were considered as saproxylic. An overall of 76 and 55 saproxylic species were collected on birch and spruce stumps respectively. Species richness was higher in birch stumps with 11 species in average per sample and only 4 in spruce ones .The results show that the tree species was the only factor significantly affecting both the species richness and the species abundance of a stump. The variable âDrynessâ had significant effect on the samplesâ species diversity with dry samples harboring a higher number of species. The proportion of stump types used by different orders clearly shows that the tree species was again the main factor influencing the species abundance of a stump. More insects were found in birch stumps, regardless of their dryness, than spruce. Wet spruce and dry birch stumps were respectively the least (7.9%) and the most used (34.1%) substrates. Coleoptera beetles were more numerous in birch stumps but did not show any preference concerning the moisture level of the stumps. The other orders showed a similar pattern with Hymenoptera, Lepidoptera insects however favoring dry birch stumps and Dipterans wet ones. Arhopalus rusticus and Curtimorda maculosa were the only species to show a significant correspondence to a substrate and were associated to spruce stumps.
The results show that both birch and spruce support the life cycle of many different insect species and not only saproxylic. As wet spruce stumps presented the lowest biodiversity, it could be thus advised, in a context of biodiversity conservation, to set aside in priority birch and more generally broadleaves stumps.Avverkningsstubbar svarar för upp till 80 % av den döda ved som lÀmnas kvar vid
slutavverkning. De förser mÄnga vedlevande insekter (insekter som Àr beroende av död ved
för att överleva) med lÀmpliga habitat att försöka sig i. Stubbrytning, som i ökande takt görs
efter slutavverkningar för att utvinna bioenergi, minskar dÀrför deras livsutrymme. De
vedlevande insekterna har sedan tidigare identifierats som en grupp som hotas av intensivt
skogsbruk och stubbrytning riskerar att ökar denna negativa pÄverkan.
PÄ grund av tekniska svÄrigheter och miljöhÀnsyn, till nÀringsurlakning och erosion, Àr
skogsstyrelsens riktlinjer för stubbrytning att man bör lÀmna stubbar i blötare partier pÄ
hyggena. Det finns dock anledning att tro att stubbar i dessa partier inte Àr lÀmpliga substrat
för vedlevande insekter. MÄlet med detta projekt var dÀrför att testa om de blött stÄende
stubbarna Àr fattigare pÄ vedlevande skalbaggsarter Àn stubbar pÄ torrare mark. Jag testade
Àven om mönstret var detsamma för gran- och björkstubbar.
Skalbaggsfaunan provtogs genom att klÀcka fram dem ur vedprover. Prover frÄn 100 stubbar
sÄgades ut och samlades in (50 gran och 50 björk) frÄn fyra slutavverkningsbestÄnd, 5 till 7 Är
gamla, utanför Uppsala i Mellansverige. Stubbarna provtogs i par, med en blött och en torrt
placerad stubbe. Inom paren var trÀdslag, diameter och solexponering desamma. Varje prov
placerades i tvÄ mÄnader i en lÄda för att skalbaggarna skulle klÀcka fram. Vedlevande
skalbaggar och fjÀrilar artbestÀmdes, andra grupper bestÀmdes till ordning eller familj.
Totalt hittades 17065 insekter frÄn 114 arter, varav 97 ansÄgs vara vedlevande. Totalt
samlades 76 respektive 55 vedlevande arter in frÄn björk- respektive granstubbar.
Artrikedomen per stubbe var ocksÄ högre i björk (genomsnitt 11 arter) Àn i gran (4 arter).
För granstubbarna var det signifikant fler arter i de torra stubbarna Àn i de blöta, medan det för
björk inte fanns nÄgon skillnad. En analys av artsammansÀttningen (ordination) kunde dock
inte detektera nÄgon skillnad mellan torra och blöta stubbar.
Slutsatsen av studien Àr att de granstubbar som lÀmnas i blöta lÀgen pÄ hyggena Àr ett sÀmre
habitat för vedlevande skalbaggar Àn stubbar i torra lÀgen. Att enbart lÀmna stubbar i blöta
lÀgen Àr sÄlunda ingen fullvÀrdig miljöhÀnsyn för den vedlevande mÄngfalden
A Tale of Two Methods: Comparing Regression and Instrumental Variables Estimates of the Effects of Preschool Child Care Type on the Subsequent Externalizing Behavior of Children in Low-Income Families
We apply instrumental variables (IV) techniques to a pooled data set of employment-focused experiments to examine the relation between type of preschool childcare and subsequent externalizing problem behavior for a large sample of low-income children. To assess the potential usefulness of this approach for addressing biases that can confound causal inferences in child care research, we compare instrumental variables results with those obtained using ordinary least squares (OLS) regression. We find that our OLS estimates concur with prior studies showing small positive associations between center-based care and later externalizing behavior. By contrast, our IV estimates indicate that preschool-aged children with center care experience are rated by mothers and teachers as having fewer externalizing problems on entering elementary school than their peers who were not in child care as preschoolers. Findings are discussed in relation to the literature on associations between different types of community-based child care and childrenâs social behavior, particularly within low-income populations. Moreover, we use this study to highlight the relative strengths and weaknesses of each analytic method for addressing causal questions in developmental research
Reproducibility of a food menu to measure energy and macronutrient intakes in a laboratory and under real-life conditions
Given the limitations associated with the measurement of food intake, we aimed to determine the reliability of a food menu to measure energy intake (EI) and macronutrient intake within the laboratory and under free-living conditions. A total of eight men and eight women (age 25·74 (sd 5·9) years, BMI 23·7 (sd 2·7) kg/m2) completed three identical in-laboratory sessions (ILS) and three out-of-laboratory sessions (OLS). During the ILS, participants had ad libitum access to a variety of foods, which they chose from a menu every hour, for 5 h. For the OLS, the foods were chosen from the menu at the start of the day and packed into containers to bring home. There were no significant differences in total EI (6118·6 (sd 2691·2), 6678·8 (sd 2371·3), 6489·5 (sd 2742·9) kJ; NS) between the three ILS and three OLS (6816·0 (sd 2713·2), 6553·5 (sd 2364·5), 6456·4 (sd 3066·8) kJ; NS). Significant intraclass correlations (ICC) for total energy (r 0·77, P < 0·0001), carbohydrate (r 0·81, P < 0·0001), dietary fat (r 0·54, P < 0·0001) and protein (r 0·81, P < 0·0001) intakes for the ILS and significant ICC for total energy (r 0·85, P < 0·0001), carbohydrate (0·85, P < 0·0001), dietary fat (0·72 P < 0·0001) and protein (0·80, P < 0·0001) intakes for the OLS were noted. The average within-subject CV for total EI was 18·3 (sd 10·0) and 16·1 (sd 10·3) % for the ILS and OLS, respectively, with a pleasantness rating for foods consumed of 124 (sd 14) mm out of 150 mm (83 %). Overall, the food menu produces a relatively reliable measure of EI inside and outside the laboratory. The results also underscore the difficulties in capturing a representative image of food intake given the relatively high day-to-day variation in the amount and composition of foods consumed
Effect of Training Systems on Accumulation of Flavan-3-ols in Cabernet Sauvignon Grape Seeds at the North Foot of Mt. Tianshan
development of Cabernet Sauvignon grapes during two consecutive seasons (2011 to 2012) in the northwest of China was evaluated. The applied training systems include the modified vertical shoot positioned(M-VSP); the fan training system with two trunks (F-TT); and the fan training system with multiple trunks (F-MT). The results show that the pattern of flavan-3-ol accumulation was similar for the three training systems in both vintages, with flavan-3-ols being the highest around véraison, before declining as harvest approaches. Compared to the 2011 vintage, the dry vintage of 2012 had a greater accumulation of total flavan-3-ols and individual flavan-3-ol monomers, including (+)-catechin (C), (-)-epicatechin (EC) and (-)-epicatechin-3-O-gallate (ECG). With regard to the effect of training systems, M-VSP contributed to a significantly higher content of total flavan-3-ols, while the percentage of ECG was lower for M-VSP. As for the three flavan-3-ol units (terminal subunits, extension subunits and monomers), the 2012 vintage was more likely to accumulate extension subunits and monomers, and the effect of training system onthese three flavan-3-ols units varied between the different vintages. Meanwhile, the proportion of ECG in terminal subunits and of C in extension subunits was higher in 2012, whereas the training system of F-TThad a higher percentage of ECG in extension subunits in both vintages. In addition, the effect of vintage on the composition of flavan-3-ols in harvested grape seeds was more obvious than that of the training system
The Immigrant-Native Born Earnings Gap in the US: a Quantile Regression Analysis and International Comparison
Immigrants, Earnings Distributions, Rates of Return, Quantile Regression
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