Eficiència relativa del cross-over respecte del disseny de grups paral·lels

L'objectiu del projecte és estudiar el benefici en la planificació d'un disseny "cross-over" comparat amb el disseny de grups paral·lels en quant a eficiència relativa, que es defineix com el quocient L'objectiu del projecte és estudiar el benefici en la planificació d'un disseny "cross-over" comparat amb el disseny de grups paral•lels en quant a eficiència relativa,que es defineix com el quocient entre la grandària de mostra d'un paral•lel i la d'un disseny "cross-over" o, equivalentment, el quocient de les variàncies de les respostes respectives

International Dispersion and Profitability: An Institution-Based Approach

This study examines the effect of international dispersion on profitability. We use an institution-based approach to propose that increases in international dispersion lead, on average, to profitability downturns. We also argue that this liability of foreignness will affect multinationals from infrastructure industries to a lesser extent because in these industries: 1) the importance of cultural fit in products is low; 2) firms possess regulatory expertise; and 3) firms have limited aggregation opportunities at the regional level. We test our hypotheses on a panel of Spanish listed firms (1986-2007). Our findings point to a negative linear relationship between international dispersion and profitability, which is flatter for infrastructure multinationals. These results contribute to a more context-based understanding of internationalization that highlights the shortcomings of establishing a dispersed international footprint

Modelització del consum elèctric a les llars espanyoles

El treball s'ha basat en models de regressió amb els quals es pretén poder fer prediccions del consum electric. L'estudi s'inicia modelant el consum de la zona climàtica B per als habitatges multifamiliars amb antiguitat menor a 20 anys; amb l'objectiu de decidir a quíns habitatges s'estendria el model per a la resta de zones i tipus de llars, cercar les variables importants que influeixen en el consum electric anual í reduir al màxim les possibles fonts de variabilitat. El resultat d'aquesta primera fase és un model base per als habitatges amb/sense calefacció electrica i amb/sense aire condicionat. Partint del model base, la fase final d'estudi es basa en l'extensió d'aquest a la resta de zones climàtiques

Modelització del consum elèctric a les llars espanyoles

El treball s'ha basat en models de regressió amb els quals es pretén poder fer prediccions del consum electric. L'estudi s'inicia modelant el consum de la zona climàtica B per als habitatges multifamiliars amb antiguitat menor a 20 anys; amb l'objectiu de decidir a quíns habitatges s'estendria el model per a la resta de zones i tipus de llars, cercar les variables importants que influeixen en el consum electric anual í reduir al màxim les possibles fonts de variabilitat. El resultat d'aquesta primera fase és un model base per als habitatges amb/sense calefacció electrica i amb/sense aire condicionat. Partint del model base, la fase final d'estudi es basa en l'extensió d'aquest a la resta de zones climàtiques

Early-Life Exposure to Outdoor Air Pollution and Respiratory Health, Ear Infections, and Eczema in Infants from the INMA Study

Background: Prenatal and early-life periods may be critical windows for harmful effects of air pollution on infant health.Objectives: We studied the association of air pollution exposure during pregnancy and the first year of life with respiratory illnesses, ear infections, and eczema during the first 12–18 months of age in a Spanish birth cohort of 2,199 infants.Methods: We obtained parentally reported information on doctor-diagnosed lower respiratory tract infections (LRTI) and parental reports of wheezing, eczema, and ear infections. We estimated individual exposures to nitrogen dioxide (NO2) and benzene with temporally adjusted land use regression models. We used log-binomial regression models and a combined random-effects meta-analysis to estimate the effects of air pollution exposure on health outcomes across the four study locations.Results: A 10-µg/m3 increase in average NO2 during pregnancy was associated with LRTI [relative risk (RR) = 1.05; 95% CI: 0.98, 1.12] and ear infections (RR = 1.18; 95% CI: 0.98, 1.41). The RRs for an interquartile range (IQR) increase in NO2 were 1.08 (95% CI: 0.97, 1.21) for LRTI and 1.31 (95% CI: 0.97, 1.76) for ear infections. Compared with NO2, the association for an IQR increase in average benzene exposure was similar for LRTI (RR = 1.06; 95% CI: 0.94, 1.19) and slightly lower for ear infections (RR = 1.17; 95% CI: 0.93, 1.46). Associations were slightly stronger among infants whose mothers spent more time at home during pregnancy. Air pollution exposure during the first year was highly correlated with prenatal exposure, so we were unable to discern the relative importance of each exposure period.Conclusions: Our findings support the hypothesis that early-life exposure to ambient air pollution may increase the risk of upper and lower respiratory tract infections in infants

Association between GIS-Based Exposure to Urban Air Pollution during Pregnancy and Birth Weight in the INMA Sabadell Cohort

Background: There is growing evidence that traffic-related air pollution reduces birth weight. Improving exposure assessment is a key issue to advance in this research area./nObjective: We investigated the effect of prenatal exposure to traffic-related air pollution via geographic information system (GIS) models on birth weight in 570 newborns from the INMA (Environment and Childhood) Sabadell cohort./nMethods: We estimated pregnancy and trimester-specific exposures to nitrogen dioxide and aromatic hydrocarbons [benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene (BTEX)] by using temporally adjusted land-use regression (LUR) models. We built models for NO2 and BTEX using four and three 1-week measurement campaigns, respectively, at 57 locations. We assessed the relationship between prenatal air pollution exposure and birth weight with linear regression models. We performed sensitivity analyses considering time spent at home and time spent in nonresidential outdoor environments during pregnancy./nResults: In the overall cohort, neither NO2 nor BTEX exposure was significantly associated with birth weight in any of the exposure periods. When considering only women who spent < 2 hr/day in nonresidential outdoor environments, the estimated reductions in birth weight associated with an interquartile range increase in BTEX exposure levels were 77 g [95% confidence interval (CI), 7–146 g] and 102 g (95% CI, 28–176 g) for exposures during the whole pregnancy and the second trimester, respectively. The effects of NO2 exposure were less clear in this subset./nConclusions: The association of BTEX with reduced birth weight underscores the negative role of vehicle exhaust pollutants in reproductive health. Time–activity patterns during pregnancy complement GIS-based models in exposure assessment

Prenatal Organochlorine Compound Exposure, Rapid Weight Gain, and Overweight in Infancy

Background: Although it has been hypothesized that fetal exposure to endocrine-disrupting chemicals may increase obesity risk, empirical data are limited, and it is uncertain how early in life any effects may begin. Objectives: We explored whether prenatal exposure to several organochlorine compounds (OCs) is associated with rapid growth in the first 6 months of life and body mass index (BMI) later in infancy. Methods: Data come from the INMA (Infancia y Medio-Ambiente) Child and Environment birth cohort in Spain, which recruited 657 women in early pregnancy. Rapid growth during the first 6 months was defined as a change in weight-for-age z-scores > 0.67, and elevated BMI at 14 months, as a z-score ≥ the 85th percentile. Generalized linear models were used to estimate the risk of rapid growth or elevated BMI associated with 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), hexachlorobenzene, β-hexachlorohexane, and polychlorinated biphenyls in first-trimester maternal serum. Results: After multivariable adjustment including other OCs, DDE exposure above the first quartile was associated with doubling of the risk of rapid growth among children of normal-weight (BMI < 25 kg/m2), but not overweight, mothers. DDE was also associated with elevated BMI at 14 months (relative risk per unit increase in log DDE = 1.50; 95% confidence interval, 1.11–2.03). Other OCs were not associated with rapid growth or elevated BMI after adjustment. Conclusions: In this study we found prenatal DDE exposure to be associated with rapid weight gain in the first 6 months and elevated BMI later in infancy, among infants of normal-weight mothers. More research exploring the potential role of chemical exposures in early-onset obesity is needed.This work was supported by grants from the Spanish Ministry of Health (FIS-PI041436), Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041), the Generalitat de Catalunya-CIRIT (Consejo Interdepartamental de Investigación e Innovación Tecnológica) (1999SGR 00241), and the Fundació Roger Torne

Lifestyle in undergraduate students and demographically matched controls during the covid-19 pandemic in Spain

Few studies have used a multidimensional approach to describe lifestyle changes among undergraduate students during the COVID-19 pandemic or have included controls. This study aimed to evaluate lifestyle behaviors and mental health of undergraduate students and compare them with an age and sex-matched control group. A cross-sectional web survey using snowball sampling was conducted several months after the beginning of COVID-19 pandemic in Spain. A sample of 221 students was recruited. The main outcome was the total SMILE-C score. Students showed a better SMILE-C score than controls (79.8 +- 8.1 vs. 77.2 +- 8.3; p < 0.001), although these differences disappeared after controlling for covariates. While groups did not differ in the screenings of depression and alcohol abuse, students reported lower rates of anxiety (28.5% vs. 37.1%; p = 0.042). A lower number of cohabitants, poorer self-perceived health and positive screening for depression and anxiety, or for depression only were independently associated (p < 0.05) with unhealthier lifestyles in both groups. History of mental illness and financial difficulties were predictors of unhealthier lifestyles for students, whereas totally/moderate changes in substance abuse and stress management (p < 0.05) were predictors for the members of the control group. Several months after the pandemic, undergraduate students and other young adults had similar lifestyles

Multicenter study of plastic vs. self-expanding metal stents in endoscopic ultrasound-guided drainage of walled-off pancreatic necrosis - PROMETHEUS: a randomized controlled trial protocol.

Background: It seems that lumen-apposing metal stents (LAMS) are displacing plastic stents in the therapy of pancreatic-fluid collection in walled-off necrosis (WON). To date, there is no quality of evidence to recommend LAMS as the standard treatment in the management of WON. The theoretical benefit of LAMS over plastic stents needs to be proven. Methods/design: This is a randomized controlled, multicenter, prospective clinical trial with two parallel groups, without masking. One-hundred and fourteen patients with WON will undergo endoscopic ultrasound (EUS)-guided transmural draining in nine tertiary hospitals in Spain and will be randomized to the LAMS or plastic-stent group. The primary endpoint is the short-term (4 weeks) clinical success determined by the reduction of the collection (to < 50% or < 5 cm in size), along with clinical improvement. Secondary endpoints: long-term (4 months) clinical success (total resolution or 5 cm), procedure duration, level of difficulty, safety, and recurrences. Discussion: The PROMETHEUS trial has been designed to determine whether LAMS are superior to plastic stents in EUS-guided transmural drainage of WON