962 research outputs found
Understanding Link Dynamics in Wireless Sensor Networks with Dynamically Steerable Directional Antennas
Abstract. By radiating the power in the direction of choice, electronicallyswitched directional (ESD) antennas can reduce network contention and avoid packet loss. There exists some ESD antennas for wireless sensor networks, but so far researchers have mainly evaluated their directionality. There are no studies regarding the link dynamics of ESD antennas, in particular not for indoor deployments and other scenarios where nodes are not necessarily in line of sight. Our long-term experiments confirm that previous findings that have demonstrated the dependence of angleof-arrival on channel frequency also hold for directional transmissions with ESD antennas. This is important for the design of protocols for wireless sensor networks with ESD antennas: the best antenna direction, i.e., the direction that leads to the highest packet reception rate and signal strength at the receiver, is not stable but varies over time and with the selected IEEE 802.15.4 channel. As this requires protocols to incorporate some form of adaptation, we present an intentionally simple and yet efficient mechanism for selecting the best antenna direction at run-time with an energy overhead below 2 % compared to standard omni-directional transmissions.
Gene polymorphism of interleukin 1 and 8 in chronic gastritis patients infected with Helicobacter pylori
Background: Epidemiological investigations have indicated that Helicobacter pylori induces inflammation in the gastric mucosa regulated by several interleukins. the genes IL1B and IL8 are suggested as key factors in determining the risk of gastritis. the aim of this paper was to evaluate the association of gene polymorphism of interleukin-1 and interleukin-8 with chronic gastrits in H. pylori infected patients. A total of 60 patients underwent endoscopic procedure. Biopsy samples were collected for urease test, histopathological and molecular exams. the DNA of theses samples was extracted for detection of H. pylori and analysis of the genes mentioned above. Patients with gastritis had a higher frequency of H. pylori-positive samples.Results: H. pylori was detected in 30/60 patients (50%) by PCR. As for polymorphism of interleukin 8 (-251) gene we observed a statistical difference when analyzed TA (p = 0.039) and TT (p = 0.047) genotypes. in the IL1B31 there was a statistical difference in TT (p = 0.01) genotype and in the IL1B-511 there wasn't any statistical difference.Conclusion: Our results suggest a strong correlation between the presence of chronic gastritis and infection by H. pylori and that IL1B-31TT and IL8-251TT genotypes appear to act as protective factors against H. pylori infection while IL8-251TA genotype may comprise a risk factor for infection with this bacterium.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Marilia Medical SchoolMarilia Med Sch FAMEMA, FAMEMA Blood Ctr, Dept Genet, Marilia, SP, BrazilSacred Heart Univ USC, Bauru, SP, BrazilMarilia Med Sch FAMEMA, Dept Digest Syst Surg, Marilia, SP, BrazilFed Univ São Paulo UNIFESP, Dept Morphol, São Paulo, BrazilMarilia Med Sch FAMEMA, Dept Radiotherapy & Oncol, Marilia, SP, BrazilFAMEMA, Hemoctr, Genet Lab, BR-17519050 São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Morphol, São Paulo, BrazilFAPESP: 0915857-9Web of Scienc
Application of a multidimensional integrated approach to the study of glaciers and related glacier lakes dynamics in the Italian Alps
Gastric atrophy and oesophageal squamous cell carcinoma: Possible interaction with dental health and oral hygiene habit
Background:Gastric fundal atrophy has been hypothesised to increase the risk of oesophageal squamous cell carcinoma (OSCC), but studies have shown inconsistent results.Methods:We measured serum pepsinogen I (PGI) and pepsinogen II (PGII) among 293 incident cases and 524 matched neighbourhood controls in a high-risk area of Northern Iran. Conditional logistic regression model was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs).Results:After controlling for age, sex, residence area and other potential confounders, gastric atrophy (defined by a validated criterion, PGI <55 μg dl-1) was associated with a two-fold increased risk (OR=2.01, 95% CI: 1.18, 3.45) of OSCC in the absence of nonatrophic pangastritis (defined as PGII <11.8 μg dl-1). Stratification by PGII decreased the misclassification errors due to cancer-induced gastritis. Presence of both poor dental health, indicated by higher than median sum of decayed, missing, and filled teeth (DMFT score), and gastric atrophy further increased the risk of OSCC (OR=4.15, 95% CI: 2.04, 8.42) with relative excess risk due to interaction (RERI) of 1.47 (95% CI: 1.15, 4.1). Coexistence of poor oral hygiene habit with gastric atrophy elevated OSCC risk eight times (OR=8.65, 95% CI: 3.65, 20.46) and the additive interaction index was marginally statistically significant (RERI=4.34, 95% CI: 1.07, 9.76).Conclusion:Gastric atrophy is a risk factor for OSCC, and poor dental health and oral hygiene habit may act synergistically in increasing the risk. © 2012 Cancer Research UK
Influence of linseed oil on the microstructure and composition of lime and lime-metakaolin pastes after a long curing time
This study investigates the effect of linseed oil on the microstructure of lime and lime-metakaolin pastes after 68 months of curing under controlled conditions. The hydrophobicity imparted by linseed oil to the pastes’ bulk was confirmed by measuring water drops’ contact angle. The results of thermal analysis, X-ray powder diffraction, and Fourier transform infrared spectroscopy showed that linseed oil significantly hindered the carbonation reaction in both lime and lime-metakaolin pastes and promoted the development of amorphous phases. The obtained results also indicated that linseed oil could foster the pozzolanic reaction in the lime-metakaolin system by stabilizing and/or promoting the development of hydration products resulting in reduced shrinkage in comparison with the reference
Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA
Correlations between charged particles in deep inelastic ep scattering have
been studied in the Breit frame with the ZEUS detector at HERA using an
integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in
terms of the angular separation between current-region particles within a cone
centred around the virtual photon axis. Long-range correlations between the
current and target regions have also been measured. The data support
predictions for the scaling behaviour of the angular correlations at high Q2
and for anti-correlations between the current and target regions over a large
range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations
and Monte Carlo models correctly describe the trends of the data at high Q2,
but show quantitative discrepancies. The data show differences between the
correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C
Measurement of event shapes in deep inelastic scattering at HERA
Inclusive event-shape variables have been measured in the current region of
the Breit frame for neutral current deep inelastic ep scattering using an
integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA.
The variables studied included thrust, jet broadening and invariant jet mass.
The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6,
where Q^2 is the virtuality of the exchanged boson and x is the Bjorken
variable. The Q dependence of the shape variables has been used in conjunction
with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative
corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure
eRAPID electronic patient self-Reporting of Adverse-events: Patient Information and aDvice: a pilot study protocol in pelvic radiotherapy.
Background: An estimated 17,000 patients are treated annually in the UK with radical radiotherapy (RT) for pelvic cancer. New treatment approaches in RT have increased survivorship and changed the subjective toxicity profile for patients who experience acute and long-term pelvic-related adverse events (AE). Multi-disciplinary follow-up creates difficulty for monitoring and responding to these events during treatment and beyond. Originally developed for use in systemic oncology therapy eRAPID (electronic patient self-Reporting of Adverse-events: Patient Information and aDvice) is an online system for patients to report AEs from home. eRAPID enables patient data to be integrated into the electronic patient records for use in clinical practice, provides patient management advice for mild and moderate AE and advice to contact the hospital for severe AE. The system has now been developed for pelvic RT patients, and we aim to test the intervention in a pilot study with staff and patients to inform a future randomised controlled trial (RCT). Methods: Eligible patients are those attending St James's University hospital cancer centre and The Christie Hospital Manchester undergoing pelvic radiotherapy+/-chemotherapy/hormonotherapy for prostate, lower gastrointestinal and gynaecological cancers. A prospective 1:1 randomised (intervention or usual care) parallel group design with repeated measures and mixed methods will be employed. We aim to recruit 168 patients following recommendations for sample size estimates for pilot studies. Participants using eRAPID will report AE (at least weekly) from home weekly for 6 weeks and 6 weeks post-treatment (12-week total) then at 18 and 24 weeks. Hospital staff will review eRAPID reports and use information during consultations. Notifications will be sent to the relevant clinical team when severe symptoms are reported. We will measure patient-reported outcomes using validated questionnaires (Functional Assessment in Cancer Therapy Scale-General (FACT-G), European Organisation for Research and Treatment of Cancer Core Quality of Life questionnaire (EORTC-QLQ-C30), process of care impact (hospital records of patient contacts and admissions) and economic variables (EQ5D-5L, patient use of resources)). Staff and patient experiences will be explored via semi-structured interviews. Discussion: The objectives are to establish feasibility, recruitment, integrity of the system and attrition rates, determine effect sizes and aid selection of the primary outcome measure for a future RCT. We will also refine the intervention by exploring staff and patient views. The overall goal of this complex intervention is to improve the safe delivery of cancer treatments, enhance patient care and standardise documentation of AE within the clinical datasets. Trial registration: ClinicalTrials.gov NCT02747264
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Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden
The observed variability of fluid chemistry at the Aespoe Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on hydrous ferric oxides involve sorption of both cations and anions. Geochemical modeling of the surface chemistry of hydrous ferric oxides (HFOs) in equilibrium with shallow HBH02 and deep KA0483A waters shows that HFOs can serve as significant, pH-sensitive sources and sinks for cations and anions. Carbonate sorption is favored especially at below-neutral pH. A greater mass of carbonate is sorbed onto HFO surfaces than is contained in the fluid when 10 g goethite, used as a proxy for HFOs, is in contact with 1 kg H{sub 2}O. The masses of sorbent required to significantly impact fluid chemistry through sorption/desorption reactions seem to be reasonable when compared to the occurrences of HFOs at Aespoe. Thus, it is possible that small changes in fluid chemistry can cause significant releases of cations or anions from HFOs into the fluid phase or, alternately, result in uptake of aqueous species onto HFO surfaces. Simulations of the mixing of shallow HBH02 and native KA0483A waters in the presence of a fixed mass of goethite show that surface complexation does not cause the concentrations of Ca, Sr, and SO{sub 4} to deviate from those that are predicted using conservative mixing models. Results for HCO{sub 3} are more difficult to interpret and cannot be addressed adequately at this time
Fieldtrips and Virtual Tours as Geotourism Resources: Examples from the Sesia Val Grande UNESCO Global Geopark (NW Italy)
In the 20th anniversary year of the European Geopark Network, and 5 years on from the receipt of the UNESCO label for the geoparks, this research focuses on geotourism contents and solutions within one of the most recently designated geoparks, admitted for membership in 2013: the Sesia Val Grande UNESCO Global Geopark (Western Italian Alps). The main aim of this paper is to corroborate the use of fieldtrips and virtual tours as resources for geotourism. The analysis is developed according to: i) geodiversity and geoheritage of the geopark territory; ii) different approaches for planning fieldtrip and virtual tours. The lists of 18 geotrails, 68 geosites and 13 off-site geoheritage elements (e.g., museums, geolabs) are provided. Then, seven trails were selected as a mirror of the geodiversity and as container of on-site and off-site geoheritage within the geopark. They were described to highlight the different approaches that were implemented for their valorization. Most of the geotrails are equipped with panels, and supported by the presence of thematic laboratories or sections in museums. A multidisciplinary approach (e.g., history, ecology) is applied to some geotrails, and a few of them are translated into virtual tours. The variety of geosciences contents of the geopark territory is hence viewed as richness, in term of high geodiversity, but also in term of diversification for its valorization
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