Aggression, impulsivity and serotonin in drug dependence

Aggression, impulsivity, and central serotonergic function were evaluated in two groups of human volunteers; one group having a history of substance dependence (DRUG+) and another group with no drug use history (DRUG$-$). The hypothesis was that DRUG+ subjects would be more aggressive, more impulsive, and have attenuated serotonergic function. Results showed that DRUG+ subjects behaved more aggressively in a computer paradigm of aggression and also reported more aggression on questionnaires than DRUG$-$ subjects. In a computer paradigm of impulsivity, the DRUG+ group showed a lesser ability to delay gratification than the DRUG$-$ group in the last session of testing. The DRUG+ subjects also reported more venturesomeness and problems associated with low impulse control on questionnaires. Serotonergic function was measured through the neuroendocrine and hypothermic response to an orally administered serotonin (5-HT) agonist specific to the 5-HT$\rm\sb{1A}$ receptor subtype (ipsapirone). The neuroendocrine responses did not differ between DRUG$\pm$ groups, indicating no difference in the sensitivity of the presynaptic or postsynaptic 5-HT$\rm\sb{1A}$ receptors. An unexpected result was that the indicator hormone, cortisol, was at a lower baseline level in the DRUG+ group than the DRUG$-$ group. Lowered cortisol levels have been previously noted in children at high risk foul antisociality and future drug use. A principal components analysis including impulsivity, aggression, and serotonergic function measures produced three unique factors. The factors, Antisocial Tendency and Self-Control and Serotonergic Function combined to produce a significant regression equation explaining 36% of variability in the DRUG$\pm$ groups. These factors included measures of aggression, impulsivity, mood, and educational attainment. These results suggest that the current measures of aggression and impulsivity were predictive of a drug dependence disorder but that neuroendocrine function is not yet a useful indicator of drug dependence status. ^

Functional error modeling for uncertainty quantification in hydrogeology

Approximate models (proxies) can be employed to reduce the computational costs of estimating uncertainty. The price to pay is that the approximations introduced by the proxy model can lead to a biased estimation. To avoid this problem and ensure a reliable uncertainty quantification, we propose to combine functional data analysis and machine learning to build error models that allow us to obtain an accurate prediction of the exact response without solving the exact model for all realizations. We build the relationship between proxy and exact model on a learning set of geostatistical realizations for which both exact and approximate solvers are run. Functional principal components analysis (FPCA) is used to investigate the variability in the two sets of curves and reduce the dimensionality of the problem while maximizing the retained information. Once obtained, the error model can be used to predict the exact response of any realization on the basis of the sole proxy response. This methodology is purpose-oriented as the error model is constructed directly for the quantity of interest, rather than for the state of the system. Also, the dimensionality reduction performed by FPCA allows a diagnostic of the quality of the error model to assess the informativeness of the learning set and the fidelity of the proxy to the exact model. The possibility of obtaining a prediction of the exact response for any newly generated realization suggests that the methodology can be effectively used beyond the context of uncertainty quantification, in particular for Bayesian inference and optimization.

Climate sensitivity of Mediterranean pine growth reveals distinct east-west dipole

The European Mediterranean region is governed by a characteristic climate of summer drought that is likely to increase in duration and intensity under predicted climate change. However, large-scale network analyses investigating spatial aspects of pre-instrumental drought variability for this biogeographic zone are still scarce. In this study we introduce 54 mid- to high-elevation tree-ring width (TRW) chronologies comprising 2186 individual series from pine trees (Pinus spp.). This compilation spans a 4000-km east–west transect from Spain to Turkey, and was subjected to quality control and standardization prior to the development of site chronologies. A principal component analysis (PCA) was applied to identify spatial growth patterns during the network's common period 1862–1976, and new composite TRW chronologies were developed and investigated. The PCA reveals a common variance of 19.7% over the 54 Mediterranean pine chronologies. More interestingly, a dipole pattern in growth variability is found between the western (15% explained variance) and eastern (9.6%) sites, persisting back to 1330 AD. Pine growth on the Iberian Peninsula and Italy favours warm early growing seasons, but summer drought is most critical for ring width formation in the eastern Mediterranean region. Synoptic climate dynamics that have been in operation for the last seven centuries have been identified as the driving mechanism of a distinct east–west dipole in the growth variability of Mediterranean pines.

Morphological variation within the diatom taxon Cyclotella comensis and its importance for quantitative temperature reconstructions

1. The morphologically complex taxon Cyclotella comensis Grunow had no clear relationship with environmental parameters in a study using sediment surface samples from the Swiss Alps. The morphological heterogeneity of the taxon was investigated by applying a principal component analysis (PCA) to 9000 presence/absence descriptions of valves from surface samples of six lakes from different altitudes (15 characteristics, 100 valves each lake). The PCA allowed the classification of six morphs, which differed mainly in size and length of striae. Photographs of the morphs are shown in this paper. 2. Sixty-eight sediment surface samples were analysed using these newly defined six morphs. Summer temperature explained a major part of the variance between the morphs as assessed by a redundancy analysis (RDA). Summer temperature optima and tolerances were estimated using weighted averaging. 3. The influence of the revised C. comensis taxonomy on the diatom inferred summer temperature of a high alpine lake is discussed in a multiproxy context for the past 800 years.

Cross-culture perspectives on fear of HIV disease and AIDS in health care workers

Health care workers have been known to carry into the workplace a variety of judgmental and negative attitudes towards their patients. In no other area of patient care has this issue been more pronounced as in the management of patients with AIDS. Health care workers have refused to treat or manage patients with AIDS and have often treated them more harshly than identically described leukemia patients. Some health care institutions have simply refused to admit patients with AIDS and even recent applicants to medical colleges and schools of nursing have indicated a preference for schools in areas with low prevalence of HIV disease. Since the attitudes of health care workers do have significant consequences on patient management, this study was carried out to determine the differences in clinical practice in Nigeria and the United States of America as it relates to knowledge of a patient's HIV status, determine HIV prevalence and culture in each of the study sites and how they impact on infection control practices, determine the relationship between infection control practices and fear of AIDS, and also determine the predictors of safe infection control practices in each of the study sites.^ The study utilized the 38-item fear of AIDS scale and the measure of infection control questionnaire for its data. Questionnaires were administered to health care workers at the university teaching hospital sites of Houston, Texas and Calabar in Nigeria. Data was analyzed using a chi-square test, and where appropriate, a student t-tests to establish the demographic variables for each country. Factor analysis was done using principal components analysis followed by varimax rotation to simple structure. The subscale scores for each study site were compared using t-tests (separate variance estimates) and utilizing Bonferroni adjustments for number of tests. Finally, correlations were carried out between infection control procedures and fear of AIDS in each study site using Pearson-product moment correlation coefficients.^ The study revealed that there were five dimensions of the fear of AIDS in health care workers, namely fear of loss of control, fear of sex, fear of HIV infection through blood and illness, fear of death and medical interventions and fear of contact with out-groups. Fear of loss of control was the primary area of concern in the Nigerian health care workers whereas fear of HIV infection through blood and illness was the most important area of AIDS related feats in United States health care workers. The study also revealed that infection control precautions and practices in Nigeria were based more on normative and social pressures whereas it was based on knowledge of disease transmission, supervision and employee discipline in the United States, and thus stresses the need for focused educational programs in health care settings that emphasize universal precautions at all times and that are sensitive to the cultural nuances of that particular environment. ^

THE BACON CHOW STUDY: THE RELATIONSHIP BETWEEN INFECTIOUS ILLNESS AND GROWTH OF INFANTS

Multiple dietary deficiencies and high rates of infectious illness are major health problems leading to malnutrition and limitation of growth of children in developing countries. Longitudinal studies which provide information on illness incidence and growth velocity are needed in order to untangle the complex interrelationship between nutrition, illness and growth. From 1967 to 1973, researchers led by Dr. Bacon Chow of the Johns Hopkins University School of Hygiene undertook a quasi-experimental prospective study in Suilin Township, Taiwan to determine the effects of a nutritional supplement to the diets of pregnant and lactating women on the growth, development and resistance to disease of their offspring. This dissertation presents results from the analysis of infant morbidity and postnatal growth.^ Maternal nutritional supplementation has no apparent effect on the postnatal growth or morbidity of infants. Significant sex differences exist in growth response to illness and in illness susceptibility. Male infants have more diarrhea and upper respiratory illness. Respiratory illness is positively associated with growth rate in weight in the first semester of life. Diarrhea is significantly negatively associated with growth in length in the second semester. Small-for-date infants are more susceptible to illness in general and have a different pattern of growth response than large-for-date infants.^ Principal components analysis of illness data is shown to be an effective technique for making more precise use of ambiguous morbidity data. Multiple regression with component scores is an accurate method for estimating variance in growth rate predicted by indepenent illness variables. A model is advanced in which initial postnatal growth rate determines subsequent susceptibility to nutritional stress and infection. Initial growth rate is a function of prenatal nutrition, but is not significantly affected by maternal supplementation during gestation or lactation. Critical evaluation is made of nutritional supplementation programs which do not afford disease control.^

The heart challenge: The effect of regular aerobic exercise on body fat distribution in third and fourth grade school children: A randomized clinical trial

The pattern of body fat distribution known as "centralized", and characterized by a predominance of subcutaneous fat on the trunk and a "pot belly", has been associated with an increased risk of chronic disease. These patterns of fat distribution, as well as the lifestyle habit variables associated with adult fatness and chronic morbidity clearly begin to develop during childhood, indicating the need for intervention and primary prevention of obesity, particularly the centralized form, during childhood or adolescence. The purpose of this study was to determine whether regular aerobic exercise could beneficially alter the distribution of body fat in 8 and 9 year old children. One hundred and eighty-eight participants were randomized into either a regular aerobic exercise treatment group or a standard physical education program control group. A variety of aerobic activities was used for intervention 5 days per week during physical education class for a period of 12 weeks. Fat distribution was measured by a number of the most commonly used indices, including ratios of body circumferences and skinfolds and indices derived from a principal components analysis. Change over time in average pulse rate was used to determine if intervention actually occurred. Approximately 10% of the students were remeasured, allowing the calculation of intra- and interexaminer measurement reliability estimates for all indices.^ This study group was comparable to the U.S. population, though the study children were slightly larger for certain measures. No effect of the exercise intervention was found. The most likely explanation for this was inadequacy of the intervention, as indicated by the lack of any change in average pulse rate with treatment. The results of the measurement reliability analysis are reported and indicate that body circumference ratios are more precise than skinfold ratios, particularly when multiple observers are used. Reliability estimates for the principal component indices were also high.^ It remains unclear whether the distribution of body fat can be altered with exercise. It is likely that this issue will remain undecided until one highly reliable, valid, and sensitive measure of fat distribution can be found. ^

Neogene calcareous nannofossils in the Caribbean and the eastern equatorial Pacific

Principal components analysis of nannofossil assemblages in five ODP sites in the Caribbean and the eastern equatorial Pacific was used to monitor Neogene surface water circulation changes. In 15.83-10.71 Ma, floral distributions clearly show the existence of the Circum-tropical Current between the Caribbean and the eastern equatorial Pacific and no surface water communication between the northern and southern Caribbean. In 10.71-9.36 Ma, the Circum-tropical Current weakened and the northward intra-Caribbean current had been initiated. Northern and southern Caribbean surface waters again became separated in 8.35-3.65 Ma and the Circum-tropical Current was regenerated. After 2.76 Ma, the northward intra-Caribbean current has completely been established and the Circum-tropical Current disappeared. This suggests that a barrier to the Circum-tropical Current had formed, indicating the final closure of the Isthmus of Panama.

Paleoproductivity reconstruction for the eastern equatorial Pacific

Productivity at six core locations in the eastern equatorial Pacific (EEP) was reconstructed with a benthic foraminiferal transfer function. The core records show strong regionality, especially where affected by Peru margin upwelling of deeper Equatorial Undercurrent Water (EUC) (originally coming from the subantarctic). This "Peru margin" record differs from that seen along the equator where divergence leads to shallow upwelling, and it is generally inverse to that seen in cores outside the areas of equatorial upwelling. Principal components analysis shows that the main productivity pattern correlates well to the global oxygen isotope record and has lowest values during isotope stages 2 and 4. In addition to this, equatorial cores show a higher frequency pattern of variation which becomes much more pronounced during MIS 3 and 2. The reconstructions based on benthic foraminifera were tested against those from nonaccumulation rate based inorganic chemical proxies of export production. These were found to correlate well in the region influenced by Peru upwelling, and also to share common features for sites along the equator. All the nonaccumulation rate based paleotracers are consistent with one another and differ from accumulation rate derived proxies. The differences between the two classes of paleotracers may result from uncertainties in calculating actual biogenic fluxes since 230Th-normalized results conform more to those we obtained. Analysis of planktonic carbon isotope values for the EEP, and their comparison to the record of the Pacific subantarctic, indicates that the subantarctic contribution to the EUC was reduced during MIS 3 and 2.

Análisis de componentes principales con datos georreferenciados : una aplicación en agricultura de precisión

La utilización de nuevas tecnologías asociadas a la agricultura de precisión permite capturar información de múltiples variables en gran cantidad de sitios georreferenciados dentro de lotes en producción. Las covariaciones espaciales de las propiedades del suelo y el rendimiento del cultivo pueden evaluarse a través del análisis de componentes principales clásico (PCA). No obstante, como otros métodos multivariados descriptivos, el PCA no ha sido desarrollado explícitamente para datos espaciales. Nuevas versiones de análisis multivariado permiten contemplar la autocorrelación espacial entre datos de sitios vecinos. En este trabajo se aplican y comparan los resultados de dos técnicas multivariadas, el PCA y MULTISPATI-PCA. Este último incorpora la información espacial a través del cálculo del índice de Moran entre los datos de un sitio y el dato promedio de sus vecinos. Los resultados mostraron que utilizando MULTISPATI-PCA se detectaron correlaciones entre variables que no fueron detectadas con el PCA. Los mapas de variabilidad espacial construidos a partir de la primera componente de ambas técnicas fueron similares; no así los de la segunda componente debido a cambios en la estructura de co-variación identificada, al corregir la variabilidad por la autocorrelación espacial de los datos. El método MULTISPATI-PCA constituye una herramienta importante para el mapeo de la variabilidad espacial y la identificación de zonas homogéneas dentro de lotes.

Ordenaciones de material genético a partir de información multidimensional

Nuevas biotecnologías permiten obtener información para caracterizar materiales genéticos a partir de múltiples marcadores, ya sean éstos moleculares y/o morfológicos. La ordenación del material genético a través de la exploración de patrones de variabilidad multidimensionales se aborda mediante diversas técnicas de análisis multivariado. Las técnicas multivariadas de reducción de dimensión (TRD) y la representación gráfica de las mismas cobran sustancial importancia en la visualización de datos multivariados en espacios de baja dimensión ya que facilitan la interpretación de interrelaciones entre las variables (marcadores) y entre los casos u observaciones bajo análisis. Tanto el Análisis de Componentes Principales, como el Análisis de Coordenadas Principales y el Análisis de Procrustes Generalizado son TRD aplicables a datos provenientes de marcadores moleculares y/o morfológicos. Los Árboles de Mínimo Recorrido y los biplots constituyen técnicas para lograr representaciones geométricas de resultados provenientes de TRD. En este trabajo se describen estas técnicas multivariadas y se ilustran sus aplicaciones sobre dos conjuntos de datos, moleculares y morfológicos, usados para caracterizar material genético fúngico.

Antropología social y sociología argentinas : Identidades disciplinares en cuatro congresos

En este artículo se toman como objeto la antropología social y la sociología argentinas en su estado actual. Comenzando por un comentario general sobre la relación entre estas disciplinas y sobre su institucionalización en Argentina desde 1957, se pasa luego a la descripción de una de las hipotéticas dimensiones de su diferenciación basada en un análisis de componentes principales (ACP) sobre las ponencias presentadas en cuatro reuniones científicas en cuanto a la estructura de sus referentes teóricos y metodológicos. Los resultados muestran una superposición de referencias lo suficientemente importante como para asentar la idea de que las razones para la diferenciación entre estas disciplinas están lejos de obedecer a factores vinculados ala epistemología, la metodología o la teoría. Finalmente, retomando ideas de Abbott y Passeron, se argumenta sobre una posible comunidad única de cientistas sociales

Antropología social y sociología argentinas : Identidades disciplinares en cuatro congresos

En este artículo se toman como objeto la antropología social y la sociología argentinas en su estado actual. Comenzando por un comentario general sobre la relación entre estas disciplinas y sobre su institucionalización en Argentina desde 1957, se pasa luego a la descripción de una de las hipotéticas dimensiones de su diferenciación basada en un análisis de componentes principales (ACP) sobre las ponencias presentadas en cuatro reuniones científicas en cuanto a la estructura de sus referentes teóricos y metodológicos. Los resultados muestran una superposición de referencias lo suficientemente importante como para asentar la idea de que las razones para la diferenciación entre estas disciplinas están lejos de obedecer a factores vinculados ala epistemología, la metodología o la teoría. Finalmente, retomando ideas de Abbott y Passeron, se argumenta sobre una posible comunidad única de cientistas sociales

Antropología social y sociología argentinas : Identidades disciplinares en cuatro congresos

En este artículo se toman como objeto la antropología social y la sociología argentinas en su estado actual. Comenzando por un comentario general sobre la relación entre estas disciplinas y sobre su institucionalización en Argentina desde 1957, se pasa luego a la descripción de una de las hipotéticas dimensiones de su diferenciación basada en un análisis de componentes principales (ACP) sobre las ponencias presentadas en cuatro reuniones científicas en cuanto a la estructura de sus referentes teóricos y metodológicos. Los resultados muestran una superposición de referencias lo suficientemente importante como para asentar la idea de que las razones para la diferenciación entre estas disciplinas están lejos de obedecer a factores vinculados ala epistemología, la metodología o la teoría. Finalmente, retomando ideas de Abbott y Passeron, se argumenta sobre una posible comunidad única de cientistas sociales

Geochemical data from pore water and solids from cores GS08-153-91GC12 and GS08-153-53-GC6, Arctic Mid-Ocean Ridge

Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in geochemical composition and prokaryotic community structure within deep-sea sediments. We obtained comprehensive geochemical data from two gravity cores near the hydrothermal vent field Loki's Castle at the Arctic Mid-Ocean Ridge, in the Norwegian-Greenland Sea. Geochemical properties in the rift valley sediments exhibited strong centimeter-scale stratigraphic variability. Microbial populations were profiled by pyrosequencing from 15 sediment horizons (59,364 16S rRNA gene tags), quantitatively assessed by qPCR, and phylogenetically analyzed. Although the same taxa were generally present in all samples, their relative abundances varied substantially among horizons and fluctuated between Bacteria- and Archaea-dominated communities. By independently summarizing covariance structures of the relative abundance data and geochemical data, using principal components analysis, we found a significant correlation between changes in geochemical composition and changes in community structure. Differences in organic carbon and mineralogy shaped the relative abundance of microbial taxa. We used correlations to build hypotheses about energy metabolisms, particularly of the Deep Sea Archaeal Group, specific Deltaproteobacteria, and sediment lineages of potentially anaerobic Marine Group I Archaea. We demonstrate that total prokaryotic community structure can be directly correlated to geochemistry within these sediments, thus enhancing our understanding of biogeochemical cycling and our ability to predict metabolisms of uncultured microbes in deep-sea sediments.