Doubly Robust Inference when Combining Probability and Non-probability Samples with High-dimensional Data

Non-probability samples become increasingly popular in survey statistics but may suffer from selection biases that limit the generalizability of results to the target population. We consider integrating a non-probability sample with a probability sample which provides high-dimensional representative covariate information of the target population. We propose a two-step approach for variable selection and finite population inference. In the first step, we use penalized estimating equations with folded-concave penalties to select important variables for the sampling score of selection into the non-probability sample and the outcome model. We show that the penalized estimating equation approach enjoys the selection consistency property for general probability samples. The major technical hurdle is due to the possible dependence of the sample under the finite population framework. To overcome this challenge, we construct martingales which enable us to apply Bernstein concentration inequality for martingales. In the second step, we focus on a doubly robust estimator of the finite population mean and re-estimate the nuisance model parameters by minimizing the asymptotic squared bias of the doubly robust estimator. This estimating strategy mitigates the possible first-step selection error and renders the doubly robust estimator root-n consistent if either the sampling probability or the outcome model is correctly specified

Urban football narratives and the colonial process in Lourenço Marques

Support for Portuguese football teams, in Mozambique as well as in other former Portuguese colonies, could be interpreted either as a sign of the importance of a cultural colonial heritage in Africa or as a symbol of a perverse and neo-colonial acculturation. This article, focused on Maputo, the capital of Mozambique – formerly called Lourenc¸o Marques – argues that in order to understand contemporary social bonds, it is crucial to research the connection between the colonial process of urbanisation and the rise of urban popular cultures. Despite the existence of social discrimination in colonial Lourenc¸o Marques, deeply present in the spatial organisation of a city divided between a ‘concrete’ centre and the immense periphery, the consumption of football, as part of an emergent popular culture, crossed segregation lines. I argue that football narratives, locally appropriated, became the basis of daily social rituals and encounters, an element of urban sociability and the content of increasingly larger social networks. Therefore, the fact that a Portuguese narrative emerged as the dominant form of popular culture is deeply connected to the growth of an urban community

Prebiotics from Marine Macroalgae for Human and Animal Health Applications

The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds) are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential applications of prebiotics, followed by an outline of the chemistry of seaweed polysaccharides. Their potential for use as prebiotics for both humans and animals will be highlighted by reviewing data from both in vitro and in vivo studies conducted to date

Cold comfort: Arctic seabirds find refugia from climate change and potential competition in marginal ice zones and fjords

Climate change alters species distributions by shifting their fundamental niche in space through time. Such effects may be exacerbated by increased inter-specific competition if climate alters species dominance where competitor ranges overlap. This study used census data, telemetry and stable isotopes to examine the population and foraging ecology of a pair of Arctic and temperate congeners across an extensive zone of sympatry in Iceland, where sea temperatures varied substantially. The abundance of Arctic Brünnich’s guillemot Uria lomvia declined with sea temperature. Accessibility of refugia in cold water currents or fjords helped support higher numbers and reduce rates of population decline. Competition with temperate Common guillemots Uria aalge did not affect abundance, but similarities in foraging ecology were sufficient to cause competition when resources are limiting. Continued warming is likely to lead to further declines of Brünnich’s guillemot, with implications for conservation status and ecosystem services

Optimizing the diagnostic work-up of acute uncomplicated urinary tract infections

<p>Abstract</p> <p>Background</p> <p>Most diagnostic tests for acute uncomplicated urinary tract infections (UTIs) have been previously studied in so-called single-test evaluations. In practice, however, clinicians use more than one test in the diagnostic work-up. Since test results carry overlapping information, results from single-test studies may be confounded. The primary objective of the Amsterdam Cystitis/Urinary Tract Infection Study (ACUTIS) is to determine the (additional) diagnostic value of relevant tests from patient history and laboratory investigations, taking into account their mutual dependencies. Consequently, after suitable validation, an easy to use, multivariable diagnostic rule (clinical index) will be derived.</p> <p>Methods</p> <p>Women who contact their GP with painful and/or frequent micturition undergo a series of possibly relevant tests, consisting of patient history questions and laboratory investigations. Using urine culture as the reference standard, two multivariable models (diagnostic indices) will be generated: a model which assumes that patients attend the GP surgery and a model based on telephone contact only. Models will be made more robust using the bootstrap. Discrimination will be visualized in high resolution histograms of the posterior UTI probabilities and summarized as 5^th, 10^th, 25^th50^th, 75^th, 90^th, and 95^thcentiles of these, Brier score and the area under the receiver operating characteristics curve (ROC) with 95% confidence intervals. Using the regression coefficients of the independent diagnostic indicators, a diagnostic rule will be derived, consisting of an efficient set of tests and their diagnostic values.</p> <p>The course of the presenting complaints is studied using 7-day patient diaries. To learn more about the natural history of UTIs, patients will be offered the opportunity to postpone the use of antibiotics.</p> <p>Discussion</p> <p>We expect that our diagnostic rule will allow efficient diagnosis of UTIs, necessitating the collection of diagnostic indicators with proven added value. GPs may use the rule (preferably after suitable validation) to estimate UTI probabilities for women with different combinations of test results. Finally, in a subcohort, an attempt is made to identify which indicators (including antibiotic treatment) are useful to prognosticate recovery from painful and/or frequent micturition.</p

Now Showing Patrick Staff

Patrick Staff presented Noski Deville's film Loss of Heat (1994) at London's The Showroom on 14 December 2016. Organised by the monthly program Cinenova: Now Showing, interdisciplinary artist Patrick Staff will show the celebrated director and cinematographer Noski Deville whose film explores epilepsy in a 'magical realist portrayal of queer love' and a portrayal of the relationship between the carer and the cared for. Cinenova is a feminist film organisation that focuses on contemporary moving image and the Now Showing program is working with its archive to re-present what is in the collection. In addition to the screening, Patrick Staff will also present a text and video-in progress to prelude their coming solo show Weed Killer at Los Angeles’ MOCA in 2017 that looks at 'illness and gender, and particularly the intersections of queer identity, cross-generational dialogue, and the fine line between states that both poison and nourish.

Répartition des familles selon le nombre des enfants : un modèle et son application à la fécondité différentielle

Degiovanni Patrick, Deville Jean-Claude, Gubian Alain. — A Model of the Distribution of Family Size and its Application to the Study of Differential Fertility. The lognormal distribution is fitted to the distribution of family sizes by using three parameters : the proportion of childless families, for those with one child or more the maximum likelihood estimate of the mean and variance of the corresponding normal distribution is used. The method is applied to a number of distributions of family size obtained from various surveys carried out by INSEE. Variations in the mean which depend on the social environment, the age at marriage, the number of children of the spouses' parents, the difference between the age of the spouses and the educational level achieved by the mother are well known, but relatively less is known about fluctuations in the variance. These show up differences in the behaviour of certain social groups and also show the process of convergence of behaviour which is currently in progress in France. A reduction of the variance when the mean remains constant will result in a decline of fertility.Degiovanni Patrick, Deville Jean-Claude, Gubian Alain. — Répartition des familles selon le nombre d'enfants : un modèle et son application à la fécondité différentielle. On ajuste une loi lognormale à la répartition des familles selon le nombre de leurs enfants en utilisant trois paramètres : la proportion de familles sans enfants, puis pour celles qui ont un enfant, l'ajustement lognormal, avec estimation par le maximum de vraisemblance de la moyenne et de la variance de la loi normale correspondante. Cette technique est appliquée à de nombreuses distributions tirées des enquêtes familles de l'INSEE. Les variations de la moyenne selon le milieu social, l'âge au mariage, le nombre d'enfants de la mère du mari ou de la femme, l'écart d'âge des époux ou le diplôme obtenu par la femme sont conformes à ce que l'on sait déjà, mais les variations de la variance sont moins connues. Elles montrent l'hétérogénéité de certaines classes sociales ou catégories, elles permettent aussi de suivre le vaste mouvement d'homogénéisation actuellement en cours en France. Ajoutons qu'à norme constante (définie par la moyenne de la loi normale), le resserrement des comportements mesuré par la diminution de variance a pour effet une diminution de la fécondité.Degiovanni Patrick, Deville Jean-Claude, Gubian Alain. — Distribution de las familias según el numero de hijos : un modelo y su aplicación a la fecundidad diferenciál. Se ajusta una ley lognormal a la distribution de familias según el numero de sus hijos utilizando très paramètres : la proportion de familias sin hijos y enseguida la proporciôn de familias con un sólo hijo, el ajuste lognormal, con estimación mediante el método de maxima verosimilitud de la media y de la varianza de la ley normal correspondiente. Esta técnica es aplicada a numerosas distribuciones obtenidas de las encuestas familiares del INSEE. Las variaciones de la media según el medio social, la edad al casarse, el numero de hijos de la madré del esposo о de la esposa, la diferencia de edades entre los dos esposos, o el diploma obtenido por la esposa, concuerdan con los resultados obtenidos en otros estudios, pero las variaciones de la varianza son menos conocidas. Estas variaciones muestran la heterogeneidad de ciertas clases sociales о categories y permiten también observar el vasto movimiento de homogeneización que se desarrolla actualmente en Francia. Agreguemos que a norma constante (definida para la media de la ley normal), la constriction de los comportamientos medida por la disminución de la varianza tiene por efecto una disminución de la fecundidad.Degiovanni Patrick, Deville Jean-Claude, Gubian Alain. Répartition des familles selon le nombre des enfants : un modèle et son application à la fécondité différentielle. In: Population, 39ᵉ année, n°3, 1984. pp. 563-586

Identification by PCR of genes encoding multiple response regulators

Environmental sensing in bacteria often involves the concerted action of sensor kinases and response regulators. Degenerate oligonucleotide primers were designed on the basis of amino acid similarity in the response regulators of these two-component systems. The primers were used in PCR to specifically amplify an internal DNA segment corresponding to the receiver module domain from genes encoding response regulators. Amplification products of the expected size were obtained from 12 different Gram-positive and Gramnegative bacteria. Sequence analysis revealed that 22 DNA fragments, which clearly originated from response regulator genes, were amplified from Escherichia coli, Agrobacterium tumefaciens, Bacillus subtilis and Lactobacillus bulgaricus. In each of these four species the receiver module of putative response regulator genes, which do not seem to be related to any of the already characterized genes, was identified. This simple and powerful method is therefore particularly useful for discovering new signal transduction systems which cannot be revealed by usual genetic studies

Coupled chemo-transport-mechanical modelling and numerical simulation of external sulfate attack in mortar

International audienceWe develop and apply in this study a chemo-transport-mechanical model for simulating the external sulfate attacks in Portland (CEM I) cement pastes and mortars. Basically, this degradation consists in the simultaneous decalcification of the hydrated phases resulting from leaching processes, and the migration of sulfate ions within the material and its subsequent interactions with these phases. The sulfate uptake leads generally to ettringite precipitation mainly from monosulfate, which in turn may produce intense macroscopic expansions and cracking. In our approach, crystallization pressures arising from the restrained growth of monosulfate crystals due to the confinement of the surrounding C–S–H matrix are assumed to initiate the observed macroscopic expansions. A macroscopic strain tensor evaluated from the volume fraction of supplementary precipitated ettringite is further introduced in the mechanical behavior law for explicitly reproducing the macroscopic expansions. Analytical homogenization schemes are applied to estimate both mechanical and diffusive properties from the local volume fraction of solid phases. The numerical platform Alliances is then used for solving both reactive transport and mechanical coupled problems, and is applied to the simulation of laboratory tests consisting in prismatic mortar specimens immersed in solutions containing sodium sulfate and subjected to free expansions. Comparison of the numerical results with experimental ones in terms of phase assemblage profiles, evolutions of mass changes and expansions shows a correct agreement. Finally, the extension of the model towards cases of restrained displacement conditions is discussed and some modifications regarding the kinetics of ettringite precipitation are proposed for such situations

Specific cationic emission of cisplatin following ionization by swift protons

We have investigated collision-induced ionization and fragmentation by 100 keV protons of the radio sensitizing molecule cisplatin, which is used in cancer treatments. A large emission of HCl+ and NH\hbox{$_{\mathrm{2}}^{\mathrm{+}}$} is observed, but surprisingly, no cationic fragments containing platinum are detected, in contrast to ionization-dissociation induced by electronic collision. Theoretical investigations show that the ionization processes take place on platinum and on chlorine atoms. We propose new ionization potentials for cisplatin. Dissociation limits corresponding to the measured fragmentation mass spectrum have been evaluated and the theoretical results show that the non-observed cationic fragments containing platinum are mostly associated with low dissociation energies. We have also investigated the reaction path for the hydrogen transfer from the NH3 group to the Cl atom, as well as the corresponding dissociation limits from this tautomeric form. Here again the cations containing platinum correspond to lower dissociation limits. Thus, the experimental results suggest that excited states, probably formed via inner-shell ionization of the platinum atom of the molecule, correlated to higher dissociation limits are favored