Biodiversity in drinking water distribution systems:a brief review

In drinking water distribution systems, three groups of living organisms are usually found in the biofilm and circulating water: heterotrophic bacteria, free-living protozoa, and macro-invertebrates. Indirect evidence suggests that protozoa grazing in distribution systems can partially eliminate biomass production and accidental microbiological pollution. This paper examines the biodiversit in drinking water distribution systems

Quantum information transfer for qutrits

We propose a scheme for the transfer of quantum information among distant qutrits. We apply this scheme to the distribution of entanglement among distant nodes and to the generation of multipartite antisymmetric states. We also discuss applications to quantum secret sharing

Les tunnels alpins : observatoires de l’hydrogéologie des grands massifs montagneux

International audienceL'étude des venues d'eau rencontrées lors de la réalisation d'ouvrages souterrains au travers des Alpes a permis de caractériser les circulations profondes d'eau souterraine au sein de ces massifs montagneux. Les principaux résultats sont illustrés au moyen de l'exemple du tunnel du Mont-Blanc. Les perméabilités mesurées dans les tunnels sont dépendantes de trois paramètres : l'échelle (forte variabilité des perméabilités dans les petits tronçons), la lithologie (roches cristallines plus perméables que les roches cristallophylliennes) et la profondeur (décroissance de perméabilité avec la profondeur du tunnel) des tronçons considérés. Une zone décomprimée caractérise les 600 premiers mètres au sein desquels la perméabilité est plus élevée. La température des eaux s'avère être un traceur efficace des circulations d'eau dans les massifs, l'eau s'infiltrant en altitude à température peu élevée contribuant au refroidissement des massifs. Les âges des eaux sont cohérents avec l'hydrodynamisme du massif, avec la présence d'eaux anciennes dans les parties les moins perméables et d'eaux récentes dans les zones les plus perméables. Un mélange d'eaux récentes et anciennes est observé dans les zones à perméabilité intermédiaire. Dans la plupart des ouvrages, les teneurs en Oxygène-18 sont compatibles avec des aires de recharge situées verticalement au droit des venues d'eau. Seules quelques exceptions mettent en évidence des circulations régionales, l'influence de la zone décomprimée ou l'infiltration d'eaux de surface (lacs)

Using GIS to integrate old and new archaeological data from Stone Age deposits in Karonga, Malawi

The Karonga District of northern Malawi has an extensive Stone Age archaeological record, primarily represented by stone artefacts that occur in both superficial and buried contexts. Work conducted in the 1960s provided initial documentation of this record. Some of this was presented in summary form in a small number of publications. However, most data were restricted to unpublished field notes, maps, and other static or largely inaccessible formats. GIS has been an essential tool for bringing together these diverse datasets in a digital format to facilitate integration of new research and promote reinvestigation of old sites. Examples from both the regional and site scale demonstrate how old data have been combined with recent survey and excavation data to document, analyse, interpret, and archive current knowledge about the rich Stone Age record of northern Malawi. A significant result from this approach has been the suggested reinterpretation of the Mwanganda’s Village Site

The pathological physiology of helminth infestations. 1. Ostertagia circumcincta

An experiment is described in which two sheep were artificially infested with 0. circumcincta and a third kept as an uninfested control. Plastic abomasal fistulae were inserted in these sheep and their erythrocytes were labelled with ⁵¹Cr. Radioactivity counts on blood and abomasal contents were done at regular intervals as well as other reactions being noted. The main findings were:- (i) No abnormal decrement in blood counts or increase in abomasal counts. (ii) An increase in abomasal pH and decrease in pepsin concentration. (iii) Anorexia and weight loss.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.ab201

Numerical modelling of subglacial ribs, drumlins, herringbones, and mega-scale glacial lineations reveals their developmental trajectories and transitions

Initially a matter of intellectual curiosity, but now important for understanding ice-sheet dynamics, the formation of subglacial bedforms has been a subject of scientific enquiry for over a century. Here, we use a numerical model of the coupled flow of ice, water, and subglacial sediment to explore the formation of subglacial ribs (i.e., ribbed moraine), drumlins and mega-scale glacial lineations (MSGLs). The model produces instabilities at the ice–bed interface, which result in landforms resembling subglacial ribs and drumlins. We find that a behavioural trajectory is present. Initially subglacial ribs form, which can either develop into fields of organized drumlins, or herringbone-type structures misaligned with ice flow. We present potential examples of these misaligned bedforms in deglaciated landscapes, the presence of which means caution should be taken when interpreting cross-cutting bedforms to reconstruct ice flow directions. Under unvarying ice flow parameters, MSGLs failed to appear in our experiments. However, drumlin fields can elongate into MSGLs in our model if low ice–bed coupling conditions are imposed. The conditions under which drumlins elongate into MSGLs are analogous to those found beneath contemporary ice streams, providing the first mechanism, rather than just an association, for linking MSGLs with ice stream flow. We conclude that the instability theory, as realized in this numerical model, is sufficient to explain the fundamental mechanics and process-interactions that lead to the initiation of subglacial bedforms, the development of the distinctive types of bedform patterns, and their evolutionary trajectories. We therefore suggest that the first part of the longstanding ‘drumlin problem’ – how and why they come into existence – is now solved. However, much remains to be discovered regarding the exact sedimentary and hydrological processes involved

Proton structure function at small Q^2

A fit is made to the data for the proton structure function up to Q^2=10 GeV^2, including the real gamma p total cross-section. It is economical and simple, and its form is motivated by physical principles. It is extrapolated down to very small values of x. Data for the ratio (nu W_2^n/nu W_2^p) are also fitted. A FORTRAN program for the fit to (nu W_2^p) is available by email on request Figure 5 from the original version has been deleted.Comment: 10 pages plus 9 figure

Comorbidities, exposure to medications, and the risk of community-acquired clostridium difficile infection: A systematic review and meta-analysis

Background. Clostridium difficile infection (CDI) has been extensively escribedin healthcare settings; however, risk factor sassociated with community-acquired (CA) CDI remain uncertain. This study aimed to synthesize the current evidence for an association between commonly prescribed medications and comorbidities with CA-CDI. methods. A systematic search was conducted in 5 electronic databases for epidemiologicstudi esthatexamined the associtation between the presence of comorbidities and exposure to medications with the risk of CA-CDI. Pooled odds ratios were estimated using 3 meta-analytic methods. Subgroup analyses by location of studies and by life stages were conducted. results. Twelve publications (n=56,776 patients) met inclusion criteria. Antimicrobial (odds ratio, 6.18; 95% CI, 3.80-10.04) and corticosteroid (1.81; 1.15-2.84) exposure were associated with increased risk of CA-CDI. Among the comorbidities, inflammatory bowel disease (odds ratio, 3.72; 95% CI, 1.52-9.12), renal failure (2.64; 1.23-5.68), hematologic cancer (1.75; 1.02-5.68), and diabetes mellitus (1.15; 1.05-1.27) were associated with CA-CDI. By location, antimicrobial exposure was associated with a higher risk of CA-CDI in the United States, whereas proton-pump inhibitor exposure was associated with a higher risk in Europe. By life stages, the risk of CA-CDI associated with antimicrobial exposure greatly increased in adults older than 65 years. conclusions. Antimicrobial exposure was the strongest risk factor associated with CA-CDI. Further studies are required to investigate the risk of CA-CDI associated with medications commonly prescribed in the community. Patients with diarrhea who have inflammatory bowel disease, renal failure, hematologic cancer, or diabetes are appropriate populations for interventional studies of screening

Devising quality assurance procedures for assessment of legacy geochronological data relating to deglaciation of the last British-Irish Ice Sheet

This contribution documents the process of assessing the quality of data within a compilation of legacy geochronological data relating to the last British-Irish Ice Sheet, a task undertaken as part of a larger community-based project (BRITICE-CHRONO) that aims to improve understanding of the ice sheet's deglacial evolution. As accurate reconstructions depend on the quality of the available data, some form of assessment is needed of the reliability and suitability of each given age(s) in our dataset. We outline the background considerations that informed the quality assurance procedures devised given our specific research question. We describe criteria that have been used to make an objective assessment of the likelihood that an age is influenced by the technique specific sources of geological uncertainty. When these criteria were applied to an existing database of all geochronological data relating to the last British-Irish Ice Sheet they resulted in a significant reduction in data considered suitable for synthesis. The assessed data set was used to test a Bayesian approach to age modelling ice stream retreat and we outline our procedure that allows us to minimise the influence of potentially erroneous data and maximise the accuracy of the resultant age models

On the application of radio frequency voltages to ion traps via helical resonators

Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit