Tratamiento multivariado de subpoblaciones en una gran encuesta social: la construcción de zonas sociales

Cuando se realiza una encuesta social en un amplio territorio queda siempre el deseo de aplicar análisis similares a los realizados en la encuesta a poblaciones o territorios más reducidos, evidentemente utilizando los propios datos de la encuesta. El objetivo de este articulo consiste en mostrar cómo cada estrato de una muestra estratificada puede constituir una base muestral para llevar a cabo dichos análisis con todas las garantías de precisión o, al menos, con garantías calculables y aceptables sin aumentar el número muestral para la encuesta general.

Prevalence and costs of multinutrution in hospitalized patients; the PREDyCES study

Justificación y objetivos: El estudio PREDyCES® tuvo dos objetivos principales. Primero, analizar la prevalencia de desnutrición hospitalaria (DH) en España tanto al ingreso como al alta, y segundo, estimar sus costes asociados. Métodos: Estudio nacional, transversal, observacional, multicéntrico, en condiciones de práctica clínica habitual que evaluó la presencia de desnutrición hospitalaria al ingreso y al alta mediante el NRS-2002®. Una extensión del estudio analizó la incidencia de complicaciones asociadas a la desnutrición, el exceso de estancia hospitalaria y los costes sanitarios asociados a la DH. Resultados: La prevalencia de desnutrición observada según el NRS-2002® fue del 23.7%. El análisis multivariante mostró que la edad, el género, la presencia de enfermedad oncológica, diabetes mellitus, disfagia y la polimedicación fueron los factores principales que se asociaron a la presencia de desnutrición. La DH se asoció a un incremento de la estancia hospitalaria, especialmente en aquellos pacientes que ingresaron sin desnutrición y que presentaron desnutrición al alta (15.2 vs 8.0 días; p < 0.001), con un coste adicional asociado de 5.829€ por paciente. Conclusiones: Uno de cada cuatro pacientes en los hospitales españoles se encuentra desnutrido. Esta condición se asocia a un exceso de estancia hospitalaria y costes asociados, especialmente en pacientes que se desnutren durante su hospitalización. Se debería generalizar el cribado nutricional sistemático con el objetivo de implementar intervenciones nutricionales de conocida eficacia.

High-resolution mass spectrometry applied to the study of metabolome modifications in various chicken tissues after amoxicillin administration

The performance of high resolution accurate mass spectrometry (HRMS) operating in full scan MS mode was investigated for the quantitative determination of amoxicillin (AMX) as well as qualitative analysis of metabolomic profiles in tissues of medicated chickens. The metabolomic approach was exploited to compile analytical information on changes in the metabolome of muscle, kidney and liver from chickens subjected to a pharmacological program with AMX. Data consisting of m/z features taken throughout the entire chromatogram were extracted and filtered to be treated by Principal Component Analysis. As a result, it was found that medicated and non-treated animals were clearly clustered in distinct groups. Besides, the multivariate analysis revealed some relevant mass features contributing to this separation. In this context, recognizing those potential markers of each chicken class was a priority research for both metabolite identification and, obviously, evaluation of food quality and health effects associated to food consumption.

L'estadística i els nous mitjans de càlcul

Aquesta exposició vol presentar breument el ventall d'eines disponibles, la terminologia utilitzada i, en general, el marc metodològic de l'estadística exploratoria i de l'analisi de dades, el paradigma de la disciplina.En el decurs dels darrers anys, la disciplina no ha estat pas capgirada, però de tota manera sí que cal una actualització permanent.S'han forjat i provat algunes eines gairebé només esbossades, han aparegut nous dominis d'aplicació. Cal precisar la relació amb els competidors i dinamics veïns (intel·ligencia artificial, xarxes neurals, Data Mining). La perspectiva que presento dels mètodes d'anàlisi de dades emana evidentment d'un punt de vista particular; altres punts de vista poden ser igualment vàlids

Anàlisi de Procrustes i alineament molecular

L'algorisme de McLachlan per a l'alineament de dos conjunts de coordenades atòmiques és interpretat sota l'òptica de l'Anàlisi Multivariant, que posa de manifest que el plantejament d'aquest problema és equivalent al de l'anàlisi de Procrustes i que la solució proposada per Kabsch és anàloga a la de Sibson, desenvolupada independentment

MiR-SNPs as markers of toxicity and clinical outcome in Hodgkin Lymphoma patients

Background: In recent years, microRNA (miRNA) pathways have emerged as a crucial system for the regulation of tumorogenesis. miR-SNPs are a novel class of single nucleotide polymorphisms that can affect miRNA pathways. Design and Methods: We analyzed eight miR-SNPs by allelic discrimination in 141 patients with Hodgkin lymphoma and correlated the results with treatment-related toxicity, response, disease-free survival (DFS) and overall survival (OS). Results: The KRT81 (rs3660) GG genotype was associated with an increased risk of neurological toxicity (P=0.016), while patients with XPO5 (rs11077) AA or CC genotypes had a higher rate of bleomycin-associated pulmonary toxicity (P=0.048). Both miR-SNPs emerged as independent factors in the multivariate analysis. The XPO5 AA and CC genotypes were also associated with a lower response rate (P=0.036). XPO5 (P=0.039) and TRBP (rs784567) (P=0.022) genotypes emerged as prognostic markers for DFS, and XPO5 was also associated with OS (P=0.033). In the multivariate analysis, only XPO5 emerged as an independent prognostic factor for DFS (HR: 2.622; 95%CI 1.039-6.620; P=0.041). Given the influence of XPO5 and TRBP as individual markers, we then investigated the combined effect of these miR-SNPs. Patients with both the XPO5 AA/CC and TRBP TT/TC genotypes had the shortest DFS (P=0.008) and OS (P=0.008). Conclusion: miR-SNPs can add useful prognostic information on treatment-related toxicity and clinical outcome in Hodgkin lymphoma and can be used to identify patients likely to be chemoresistant or to relapse.

La Geología de los Planetas: análisis estadístico de datos composicionales al servicio de la planetología

Anàlisi estadístic de dades composicionals dels planetes

De les dades composicionals a una geometria euclidiana sobre el símplex

La reflexió sobre la naturalesa de les dades composicionals i sobre la metodologia estadística específica per a la seva anàlisi condueix a la construcció de l'espai de les composicions i a la seva estructuració com un espai vectorial euclidià, del qual el símplex n'és l'espai suport. S'il·lustren sobre el diagrama ternari alguns dels elements més característics d'aquesta geometria

Técnicas composicionales para concentraciones geoquímicas por debajo del límite de detección

In most geochemical analyses log-ratio techniques are required to analyse compositional data sets. When a chemical element is present at a low concentration in is usally identified as a value below the detection límit and added to the data set either as zero or simply by attaching a less-than label. In any case, the occirrence of such concentration prevents us from applying the log-ratio approach. We review here the tehoretical bases of the most recent proposals for dealing with these types of observation, give some advice on their practical application and illustrate their performance throgh some examples using geochemical data

Bayes linear spaces

Linear spaces consisting of σ-finite probability measures and infinite measures (improper priors and likelihood functions) are defined. The commutative group operation, called perturbation, is the updating given by Bayes theorem; the inverse operation is the Radon-Nikodym derivative. Bayes spaces of measures are sets of classes of proportional measures. In this framework, basic notions of mathematical statistics get a simple algebraic interpretation. For example, exponential families appear as affine subspaces with their sufficient statistics as a basis. Bayesian statistics, in particular some well-known properties of conjugated priors and likelihood functions, are revisited and slightly extended

The effect of scale in daily precipitation hazard assessment

Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. Events are modelled as a Poisson process and the 24 h precipitation by a Generalised Pareto Distribution (GPD) of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA) corresponds to finite support variables as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. Bayesian techniques are used to estimate the parameters. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimated GPD is mainly in the Fréchet DA, something incompatible with the common sense assumption of that precipitation is a bounded phenomenon. The bounded character of precipitation is then taken as a priori hypothesis. Consistency of this hypothesis with the data is checked in two cases: using the raw-data (in mm) and using log-transformed data. As expected, a Bayesian model checking clearly rejects the model in the raw-data case. However, log-transformed data seem to be consistent with the model. This fact may be due to the adequacy of the log-scale to represent positive measurements for which differences are better relative than absolute

Risk of hypoglycemia in newborns from mothers with gestacional diabetes

There are not enough previous publications which are focused on mothers withwell-controlled gestational diabetes mellitus (GDM) as a risk factor that determines the occurrence of neonatal hypoglycemia. In addition, approaches to blood glucose monitoring have been inconsistent and poorly defined. Our objective is to determine if being a newborn from a mother with well-controlled gestational diabetes (regardless insulin treatment) have a higher risk to develop hypoglycemia than a healthy newborn, using a defined and strict protocol. The project will take place in a regional hospital of Girona. We will recruit from 2014 to 2015 a cohort of 623 infants born in this center without any malformation or any perinatal pathology or complication, selected with a consecutive sampling. We will record sex, ethnicity and gestational age information. We will measure blood glucose levels and anthropometric measurements in newborns always taking into account the presence of well-controlled maternal gestational diabetes or not. Patients will be followed up during 24 hours to determine the incidence of hypoglycemia. We will analyze the contribution between exposure factors that we have studied and the incidence of the outcome using a multivariate analysis

The use of COOP/WONCA charts as a screen for mental disorders in the immigrant community in primary care in primary care

Aim. To evaluate the usefulness of COOP/WONCA charts as a screening tool for mental disorders in primary care in the immigrant healthcare users in Salt. To measure self-rated health of Salt immigration population using the COOP / WONCA charts and to assess its associated factorsDesign. Descriptive and transversal studyParticipants. 370 non-EU immigrants seniors selected by consecutive sampling stratified by sexMain measures. Personal information will be collected (age, sex, country of origin, years of residency in Spain, number of people living in the household and associated comorbidities). Each participant will complete the COOP/WONCA charts. An analysis of the validity of the diagnostic test will be done: sensibility, specificity, positive predictive value, negative predictive value, ROC curve and area under the curve (AUC). All variables will be subjected to descriptive analysis. Bivariate and multivariate analysis between the variables collected (sex, years of residency in Spain... ) and the results of COOP / WONCA charts will be performedResults. Preliminary results are available on a pilot test with 30 patients. The mental disorder prevalence is around 30%. Sensibility (0,89), specificity (0,89), VPP (0,80), VPN (0,94) cutoff score (3.5) and AUC (0,941). Women, people with 10 or more years of residency in Spain and unemployed people have worse self-rated healthConclusions. Based on the preliminary results, is possible to conclude that COOP/WONCA charts could be an useful, valid and applicable screening test for mental disorders in primary care with immigrant population

Drift and ownership toward a distant virtual body.

In body ownership illusions participants feel that a mannequin or virtual body (VB) is their own. Earlier results suggest that body ownership over a body seen from behind in extra personal space is possible when the surrogate body is visually stroked and tapped on its back, while spatially and temporal synchronous tactile stimulation is applied to the participant's back. This result has been disputed with the claim that the results can be explained by self-recognition rather than somatic body ownership. We carried out an experiment with 30 participants in a between-groups design. They all saw the back of a VB 1.2 m in front, that moved in real-time determined by upper body motion capture. All felt tactile stimulation on their back, and for 15 of them this was spatially and temporally synchronous with stimulation that they saw on the back of the VB, but asynchronous for the other 15. After 3 min a revolving fan above the VB descended and stopped at the position of the VB neck. A questionnaire assessed referral of touch to the VB, body ownership, the illusion of drifting forwards toward the VB, and the VB drifting backwards. Heart rate deceleration (HRD) and the amount of head movement during the threat period were used to assess the response to the threat from the fan. Results showed that although referral of touch was significantly greater in the synchronous condition than the asynchronous, there were no other differences between the conditions. However, a further multivariate analysis revealed that in the visuotactile synchronous condition HRD and head movement increased with the illusion of forward drift and decreased with backwards drift. Body ownership contributed positively to these drift sensations. Our conclusion is that the setup results in a contradiction-somatic feelings associated with a distant body-that the brain attempts to resolve by generating drift illusions that would make the two bodies coincide.

Persistence of cognitive impairment and its negative impact on psychosocial functioning in lithium-treated, euthymic bipolar patients: a 6-year follow-up study.

BACKGROUND: Previous cross-sectional studies report that cognitive impairment is associated with poor psychosocial functioning in euthymic bipolar patients. There is a lack of long-term studies to determine the course of cognitive impairment and its impact on functional outcome. Method A total of 54 subjects were assessed at baseline and 6 years later; 28 had DSM-IV TR bipolar I or II disorder (recruited, at baseline, from a Lithium Clinic Program) and 26 were healthy matched controls. They were all assessed with a cognitive battery tapping into the main cognitive domains (executive function, attention, processing speed, verbal memory and visual memory) twice over a 6-year follow-up period. All patients were euthymic (Hamilton Rating Scale for Depression score lower than 8 and Young mania rating scale score lower than 6) for at least 3 months before both evaluations. At the end of follow-up, psychosocial functioning was also evaluated by means of the Functioning Assessment Short Test. RESULTS: Repeated-measures multivariate analysis of covariance showed that there were main effects of group in the executive domain, in the inhibition domain, in the processing speed domain, and in the verbal memory domain (p<0.04). Among the clinical factors, only longer illness duration was significantly related to slow processing (p=0.01), whereas strong relationships were observed between impoverished cognition along time and poorer psychosocial functioning (p<0.05). CONCLUSIONS: Executive functioning, inhibition, processing speed and verbal memory were impaired in euthymic bipolar out-patients. Although cognitive deficits remained stable on average throughout the follow-up, they had enduring negative effects on psychosocial adaptation of patients.