How the gut links innate and adaptive immunity.

Mucosal surfaces represent the main sites in which environmental microorganisms and antigens interact with the host. Sentinel cells, including epithelial cells, lumenal macrophages, and intraepithelial dendritic cells, continuously sense the environment and coordinate defenses for the protection of mucosal tissues. The mucosal epithelial cells are crucial actors in coordinating defenses. They sense the outside world and respond to environmental signals by releasing chemokines and cytokines that recruit inflammatory and immune cells to control potential infectious agents and to attract cells able to trigger immune responses. Among immune cells, dendritic cells (DC) play a key role in controlling adaptive immune responses, due to their capacity to internalize foreign materials and to present antigens to naive T and B lymphocytes, locally or in draining organized lymphoid tissues. Immune cells recruited in epithelial tissues can, in turn, act upon the epithelial cells and change their phenotype in a process referred to as epithelial metaplasia.

Cadmium hyperaccumulation and genetic differentiation of Thlaspi caerulescens populations

Although the knowledge on heavy metal hyperaccumulation mechanisms is increasing, the genetic basis of cadmium (Cd) hyperaccurnulation remains to be elucidated. Thlaspi caerulescens is an attractive model since Cd accumulation polymorphism observed in this species suggests genetic differences between populations with low versus high Cd hyperaccumulation capacities. In our study, a methodology is proposed to analyse at a regional scale the genetic differentiation of T. caerulescens natural populations in relation to Cd hyperaccumulation capacity while controlling for different environmental, soil, plant parameters and geographic origins of populations. Twenty-two populations were characterised with AFLP markers and cpDNA polymorphism. Over all loci, a partial Mantel test showed no significant genetic structure with regard to the Cd hyperaccumulation capacity. Nevertheless, when comparing the marker variation to a neutral model, seven AFLP fragments (9% of markers) were identified as presenting particularly high genetic differentiation between populations with low and high Cd hyperaccurnulation capacity. Using simulations, the number of outlier loci was showed to be significantly higher than expected at random. These loci presented a genetic structure linked to Cd hyperaccumulation capacity independently of the geography, environment, soil parameters and Zn, Pb, Fe and Cu concentrations in plants. Using a canonical correspondence analysis, we identified three of them as particularly related to the Cd hyperaccumutation capacity. This study demonstrates that populations with low and high hyperaccurnulation capacities can be significantly distinguished based on molecular data. Further investigations with candidate genes and mapped markers may allow identification and characterization of genomic regions linked to factors involved in Cd hyperaccumulation.

Diseño de inversores de impedancias de microondas compactos basados en metamateriales: aplicación a divisores de potencia

Recientemente ha surgido un nuevo campo de investigación en el área del electromagnetismo aplicado y de la ingeniería de microondas, basado en el control de las propiedades electromagnéticas de estructuras artificiales, conocidas como metamateriales. El objetivo principal de este proyecto es el estudio y control del comportamiento de estas estructuras artificiales, y su posterior aplicación para la síntesis de dispositivos compactos de microondas. En el primer capítulo se hace una introducción a los metamateriales en la que se exponen sus principales propiedades electromagnéticas, para finalmente presentar las líneas de transmisión zurdas que se suelen utilizar en el diseño de metamateriales. En el segundo capítulo se realiza un estudio de las propiedades y del funcionamiento de una celda metamaterial. Finalmente en el tercer capítulo se exponen diferentes dispositivos diseñados mediante la utilización de este tipo de celdas.

PKS2: A link between phototropin signalling and auxin transport - a study on how plants sense and respond to light.

The blue light photoreceptors phototropins (phot1 and phot2 in Arabidopsis thaliana (L.)) carry out various light responses of great adaptive value that optimize plant growth. These processes include phototropism (the bending of an organ induced by unequal light distribution), chloroplast movements, stomatal opening, leaf flattening and solar tracking. The biochemical pathways controlling these important blue light responses are just starting to be elucidated. The PHYTOCHROME KINASE SUBSTRATE (PKS1-4) proteins - the subject of this research - have recently been identified as novel phototropism signalling components. PKS1 (the founding member of this family) interacts in a same complex in vivo with phot1 and the important phot1 signalling element NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3). This suggested that the PKS may act as early components of phot signalling. This work further investigates the role of this protein family during phototropin signalling Genetic experiments clearly showed that the PKS do not control chloroplast movements or stomatal opening. However, PKS2 plays a critical role with NPH3 during leaf flattening and solar tracking. Epistasis data indicated that both proteins act in phot1 and phot2 pathways, which is consistent with their in vivo interaction with both phototropins. Because phototropism, leaf flattening and solar tracking are developmental processes regulated by the hormone auxin, the role of PKS2 and NPH3 during auxin homeostasis was also investigated. Interestingly, PKS2 loss-of-function restores leaf flattening in the auxin transporter mutant aux1. Moreover, PKS2 and NPH3 are found in a same complex with AUX1 in vivo. Taken together, these results suggest that PKS2 may act with NPH3 as a connecting point between phot signalling and auxin transport. Further experiments were performed to explore the molecular mode of action of PKS2 and NPH3 in this process. The significance of these results is discussed.

Comparing the treatment provided by migrant and nonmigrant health professionals: dentists in Scotland

Many OECD countries are increasingly relying on migrants to address shortages of trained health professionals. One key concern is whether migrant health professionals provide equivalent health care. We compare the treatment provided by migrant and non-migrant health professionals using administrative data from the Scottish dental system. A difference-in-differences model is estimated to examine whether migrant dentists respond differently to case mix and individual circumstances as compared with their non-migrant counterparts, and assess the extent to which any differences diminish over time. After controlling for both observed and unobserved differences between individual dentists and the cohort of patients that they treat, we find that migrant dentists have marginally different practice styles, and the variation diminishes over time within two years of practice.

Regional productivity variation and the impact of public capital stock: an analysis with spatial interaction, with reference to Spain

In this paper we examine whether variations in the level of public capital across Spain‟s Provinces affected productivity levels over the period 1996-2005. The analysis is motivated by contemporary urban economics theory, involving a production function for the competitive sector of the economy („industry‟) which includes the level of composite services derived from „service‟ firms under monopolistic competition. The outcome is potentially increasing returns to scale resulting from pecuniary externalities deriving from internal increasing returns in the monopolistic competition sector. We extend the production function by also making (log) labour efficiency a function of (log) total public capital stock and (log) human capital stock, leading to a simple and empirically tractable reduced form linking productivity level to density of employment, human capital and public capital stock. The model is further extended to include technological externalities or spillovers across provinces. Using panel data methodology, we find significant elasticities for total capital stock and for human capital stock, and a significant impact for employment density. The finding that the effect of public capital is significantly different from zero, indicating that it has a direct effect even after controlling for employment density, is contrary to some of the earlier research findings which leave the question of the impact of public capital unresolved.

Is there a role for genetics in economic development?

Spolaore and Wacziarg (2009) have presented evidence supporting a role of genetic distance to the United States as a barrier to economic development. We extend their empirical work by controlling for the share of Europeans and European descendants in the population. We fi nd that the role of genetic distance disappears and o¤er two alternative interpretations of the patterns in the data.

The endodermis--development and differentiation of the plant's inner skin.

Controlling external compound entrance is essential for plant survival. To set up an efficient and selective sorting of nutrients, free diffusion via the apoplast in vascular plants is blocked at the level of the endodermis. Although we have learned a lot about endodermal specification in the last years, information regarding its differentiation is still very limited. A differentiated endodermal cell can be defined by the presence of the "Casparian strip" (CS), a cell wall modification described first by Robert Caspary in 1865. While the anatomical description of CS in many vascular plants has been very detailed, we still lack molecular information about the establishment of the Casparian strips and their actual function in roots. The recent isolation of a novel protein family, the CASPs, that localizes precisely to a domain of the plasma membrane underneath the CS represents an excellent point of entry to explore CS function and formation. In addition, it has been shown that the endodermis contains transporters that are localized to either the central (stele-facing) or peripheral (soil-facing) plasma membranes. These features suggest that the endodermis functions as a polar plant epithelium.

A bayesian spatial individual effects probit model of the 2010 UK general election

The Conservative Party emerged from the 2010 United Kingdom General Election as the largest single party, but their support was not geographically uniform. In this paper, we estimate a hierarchical Bayesian spatial probit model that tests for the presence of regional voting effects. This model allows for the estimation of individual region-specic effects on the probability of Conservative Party success, incorporating information on the spatial relationships between the regions of the mainland United Kingdom. After controlling for a range of important covariates, we find that these spatial relationships are significant and that our individual region-specic effects estimates provide additional evidence of North-South variations in Conservative Party support.

Native-like, long synthetic peptides as components of sub-unit vaccines: practical and theoretical considerations for their use in humans.

Vaccines have been used as a successful tool in medicine by way of controlling many major diseases. In spite of this, vaccines today represent only a handful of all infectious diseases. Therefore, there is a pressing demand for improvements of existing vaccines with particular reference to higher efficacy and undisputed safety profiles. To this effect, as an alternative to available vaccine technologies, there has been a drive to develop vaccine candidate polypeptides by chemical synthesis. In our laboratory, we have recently developed a technology to manufacture long synthetic peptides of up to 130 residues, which are correctly folded and biologically active. This paper discusses the advantages of the molecularly defined, long synthetic peptide approach in the context of vaccine design, development and use in human vaccination.

Accurate performance of a rat model of schizophrenia in the water maze depends on visual cue availability and stability: a distortion in cognitive mapping abilities?

Rats were treated postnatally (PND 5-16) with BSO (l-buthionine-(S,R)-sulfoximine) in an animal model of schizophrenia based on transient glutathione deficit. The BSO treated rats were impaired in patrolling a maze or a homing table when adult, yet demonstrated preserved escape learning, place discrimination and reversal in a water maze task [37]. In the present work, BSO rats' performance in the water maze was assessed in conditions controlling for the available visual cues. First, in a completely curtained environment with two salient controlled cues, BSO rats showed little accuracy compared to control rats. Secondly, pre-trained BSO rats were impaired in reaching the familiar spatial position when curtains partially occluded different portions of the room environment in successive sessions. The apparently preserved place learning in a classical water maze task thus appears to require the stability and the richness of visual landmarks from the surrounding environment. In other words, the accuracy of BSO rats in place and reversal learning is impaired in a minimal cue condition or when the visual panorama changes between trials. However, if the panorama remains rich and stable between trials, BSO rats are equally efficient in reaching a familiar position or in learning a new one. This suggests that the BSO accurate performance in the water maze does not satisfy all the criteria for a cognitive map based navigation on the integration of polymodal cues. It supports the general hypothesis of a binding deficit in BSO rats.

Authority relationships between obedience and disobedience

Recent episodes of public dissent (such as the demonstrations against G8 policies) raise the issue of the psychological processes triggered in obeying and disobeying the authority. Even if obedience to authority is an important aspect of social life and it plays a key role in maintaining social order, the concept of obedience has been studied in social psychology mainly in terms of its destructive aspects. Besides, most of the studies have overlooked the role of disobedience in the authority relationship. Disobedience may be conceived of as a protest that undermines the legitimacy of the authority or it can represent an instrument for controlling the legitimacy of the authority's demands, becoming a factor protecting against authoritarianism. In this article, a new perspective on the study of the relationship between the individual and the authority is put forward, considering obedience and disobedience as parallel concepts, each having constructive and destructive aspects. 2008 Elsevier Ltd. All rights reserved.

Testing the Tunnel Effect: Comparison, Age and Happiness in UK and German Panels

In contrast to previous results combining all ages we find positive effects of comparison income on happiness for the under 45s, and negative effects for those over 45. In the BHPS these coefficients are several times the magnitude of own income effects. In GSOEP they cancel to give no effect of effect of comparison income on life satisfaction in the whole sample, when controlling for fixed effects, and time-in-panel, and with flexible, age-group dummies. The residual age-happiness relationship is hump-shaped in all three countries. Results are consistent with a simple life cycle model of relative income under uncertainty.

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Developing a predictive understanding of subsurface flow and transport is complicated by the disparity of scales across which controlling hydrological properties and processes span. Conventional techniques for characterizing hydrogeological properties (such as pumping, slug, and flowmeter tests) typically rely on borehole access to the subsurface. Because their spatial extent is commonly limited to the vicinity near the wellbores, these methods often cannot provide sufficient information to describe key controls on subsurface flow and transport. The field of hydrogeophysics has evolved in recent years to explore the potential that geophysical methods hold for improving the quantification of subsurface properties and processes relevant for hydrological investigations. This chapter is intended to familiarize hydrogeologists and water-resource professionals with the state of the art as well as existing challenges associated with hydrogeophysics. We provide a review of the key components of hydrogeophysical studies, which include: geophysical methods commonly used for shallow subsurface characterization; petrophysical relationships used to link the geophysical properties to hydrological properties and state variables; and estimation or inversion methods used to integrate hydrological and geophysical measurements in a consistent manner. We demonstrate the use of these different geophysical methods, petrophysical relationships, and estimation approaches through several field-scale case studies. Among other applications, the case studies illustrate the use of hydrogeophysical approaches to quantify subsurface architecture that influence flow (such as hydrostratigraphy and preferential pathways); delineate anomalous subsurface fluid bodies (such as contaminant plumes); monitor hydrological processes (such as infiltration, freshwater-seawater interface dynamics, and flow through fractures); and estimate hydrological properties (such as hydraulic conductivity) and state variables (such as water content). The case studies have been chosen to illustrate how hydrogeophysical approaches can yield insights about complex subsurface hydrological processes, provide input that improves flow and transport predictions, and provide quantitative information over field-relevant spatial scales. The chapter concludes by describing existing hydrogeophysical challenges and associated research needs. In particular, we identify the area of quantitative watershed hydrogeophysics as a frontier area, where significant effort is required to advance the estimation of hydrological properties and processes (and their uncertainties) over spatial scales relevant to the management of water resources and contaminants.

Indirect costs of parasitism are shaped by variation in the type of immune challenge and food availability

Parasites can inflict indirect fitness costs to their hosts by eliciting costly immune responses. These costs depend on the type and amount of immunostimulants presented to the host immune system but also on the amount of resources available to fuel host immune responses. Here, we investigated how the relative costs of two different types of immune challenge are modulated by variation in food availability. We injected nestling tawny owls (Strix aluco) with either 10 mu g of phytohaemagglutinin (PHA) or 20 mu g of lipopolysaccharide (LPS), and subsequently raised them under two different food regimes (food-restricted vs. ad libitum). After controlling for food consumption, we found that LPS-injected nestlings lost more body mass than PHA-injected ones only when food-restricted. We also found that body mass gain of owlets fed ad libitum decreased with the intensity of the skin swelling response against LPS, but not PHA. These experimental and correlative results suggest that nestling tawny owls suffered greater immune costs when treated with LPS than PHA, and that variation in the costs of two different types of immune challenge can be exacerbated under conditions of low food availability. Our study highlights the importance of taking into consideration the interplay between host immunity and nutrition in the study of indirect costs of parasitism.