Hybrid Flooding Scheme for Mobile Ad Hoc Networks

A hybrid broadcast scheme for mobile wireless networks is proposed in this letter. The main objective is to combine different flooding schemes in order to solve the broadcast storm issue encountered by the simple flooding scheme. For this purpose, the density of nodes is taken into account using a density metric called expansion metric. In addition, in order to reduce the broken links due to mobility of nodes and increasing dissimilarity among the intermediate nodes, a forwarding zone criterion is included in the proposed schemes. The proposed approaches have been implemented and compared with pure probabilistic flooding, and simple flooding schemes

Study of impact on helicopter blade

This article presents a study of damage in structures that are similar to helicopter blade sections, subjected to an impact. These complex composite structures were impacted by a steel ball of 125 g at impact speed ranging from 30 to 130 m/s. This led to properly highlight the kinematics of the impact and to define the sequence of the damage’s mechanisms. An explicit FE model is also presented. The damage modelling of the roving is performed through a scale change. It allows a good representation of observed experimental behaviour. As the mesh density is low, it can be used for the modelling of a real structure

Comparison of metabolic abnormalities and clinical lipodystrophy 48 weeks after switching from HAART to Trizivir versus continued HAART: the Trizal study

PURPOSE: To analyze the evolution of clinical lipodystrophy (LD) and metabolic abnormalities in patients continuing to receive HAART versus patients switched to Trizivir (zidovudine, lamivudine, abacavir) after 48 weeks. METHOD: Patients treated with HAART >6 months with plasma HIV-1 RNA viral load (VL) <400 copies/mL and <50 copies/mL at screening were randomly assigned to continue HAART (103 patients) or to receive Trizivir (106 patients). Clinical LD was evaluated using a standardized patient questionnaire only at baseline, weeks 4 and 8, and then every 8 weeks until Week 48. Laboratory evaluation was performed every 4 weeks. RESULTS: The proportion of patients exhibiting >or=1 LD symptom at baseline was 40% in the Trizivir arm and 50% in HAART arm (difference not significant). After 48 weeks, the prevalence was 28% and 42% respectively (p =.03), and the median number of LD symptoms per patient was 2 in the Trizivir arm and 4 in the continued HAART arm (p =.016). Median decreases in cholesterol levels over the 48-week study period were greater in the Trizivir arm than in the continued HAART arm (-0.80 vs. -0.44 mmol/L; p lt.001). Median triglyceride levels decreased in the Trizivir arm but increased in the continued HAART arm (-0.17 and +0.01 mmol/L; p =.006). Suppression of VL was maintained in most patients with no differences between the two arms. CONCLUSION: A switch from "standard" HAART to Trizivir was associated with an improvement in clinical LD and blood lipid abnormalities after 48 weeks

First Isolation and Identification of Agriphages in Vegetable Crops in West Africa (Côte d’Ivore): Potential Uses of Biocontrol in Plants

Agriphages or bacterial viruses are ubiquitous in the environment. The discovery of virulent phages against phytobacteria improves crop growth and proposes biopesticide uses for plant diseases. In Africa, many phytobacteria like Ralstonia, Clavibacter, and Xanthomonas were reported in several regions. The study aims to evaluate the presence of agriphages for the biocontrol of phytobacteria in Côte d'Ivoire. Leaves and soil samples were collected from healthy and diseased plants, and in three sites located in Anyama, Abidjan, and Bingerville. The pretreatments occur with sterile and physiological water for leaves and soil samples respectively. The isolation of agriphages was done on specific media with Xanthomonas campestris as bacterial host. Lytic activity was tested on agar media for five bacteria strains. After DNA extraction using the Qiagen method kit, molecular confirmation of agriphages was done by Random Amplified Polymorphic DNA-PCR. From this study, five (5) agriphages were isolated in soil and leaves in site 2. These agriphages have all been isolated from Xanthomonas campestris and have a broad spectrum of lytic activity. Molecular characterization by RAPD-PCR showed that three of these agriphages are DNA phages. The dendrogram showed that phages ΦXanS1, ΦXanS2 have 93% similarities. While ΦXanS1 and ΦXanS2 are 62% similar to ΦXanF1. This study is the first reported agriphages in West Africa and their potential uses against phytobacteria for biocontrol infection in crops. &nbsp; &nbsp

First Isolation and Identification of Agriphages in Vegetable Crops in West Africa (Côte d’Ivore): Potential Uses of Biocontrol in Plants

Agriphages or bacterial viruses are ubiquitous in the environment. The discovery of virulent phages against phytobacteria improves crop growth and proposes biopesticide uses for plant diseases. In Africa, many phytobacteria like Ralstonia, Clavibacter, and Xanthomonas were reported in several regions. The study aims to evaluate the presence of agriphages for the biocontrol of phytobacteria in Côte d'Ivoire. Leaves and soil samples were collected from healthy and diseased plants, and in three sites located in Anyama, Abidjan, and Bingerville. The pretreatments occur with sterile and physiological water for leaves and soil samples respectively. The isolation of agriphages was done on specific media with Xanthomonas campestris as bacterial host. Lytic activity was tested on agar media for five bacteria strains. After DNA extraction using the Qiagen method kit, molecular confirmation of agriphages was done by Random Amplified Polymorphic DNA-PCR. From this study, five (5) agriphages were isolated in soil and leaves in site 2. These agriphages have all been isolated from Xanthomonas campestris and have a broad spectrum of lytic activity. Molecular characterization by RAPD-PCR showed that three of these agriphages are DNA phages. The dendrogram showed that phages ΦXanS1, ΦXanS2 have 93% similarities. While ΦXanS1 and ΦXanS2 are 62% similar to ΦXanF1. This study is the first reported agriphages in West Africa and their potential uses against phytobacteria for biocontrol infection in crops. &nbsp; &nbsp

Methodological issues in estimating survival in patients with multiple primary cancers: an application to women with breast cancer as a first tumour

<p>Abstract</p> <p>Background</p> <p>Comparing survival of patients with a single tumour and patients with multiple primaries poses different methodological problems. In population based studies, where we cannot rely on detailed clinical information, the issue is disentangling the share of survival probability from the first and second cancer, and their compounded effect. We examined three hypotheses: A) the survival probability since the first tumour does not change with the occurrence of a second tumour; B) the probability of surviving a tumour does not change with the presence of a previous primary; C) the probabilities of surviving two subsequent primary tumours are independent (additivity hypothesis on mortality rates).</p> <p>Methods</p> <p>We studied the survival probabilities modelling mortality rates according to hypotheses A), B) and C). Mortality rates were calculated using Aalen-Johansen estimators which allowed to discount for the lag-time survival before developing a second tumour. We applied this approach to a cohort of 436 women with breast cancer (BC) and a subsequent tumour in the resident population of Turin, Italy, between 1985 and 2002.</p> <p>Results</p> <p>We presented our results in term of a Standardised Mortality Ratio calculated (<it>SMR</it>_<it>AJ</it>) after 10 years of follow-up. For hypothesis A we observed a significant excess mortality of 2.21 (95% C.I. 1.94 – 2.45). Concerning hypothesis B we found a not significant <it>SMR</it>_{<it>AJ </it>}of 0.98 (95% C.I. 0.87 – 1.10). The additivity hypothesis (C) was not confirmed as it overestimated the risk of death, in fact <it>SMRs</it>_{<it>AJ </it>}were all below 1: 0.75 (95% C.I. 0.66 – 0.84) for BC and all subsequent cancers, 0.72 (95% C.I. 0.55 – 0.94) for BC and colon-rectum cancer, 0.76 (95% C.I. 0.48 – 1.14) for BC and corpus uteri cancer (not significant).</p> <p>Conclusion</p> <p>This method proved to be useful in disentangling the effect of different subsequent cancers on mortality. In our application it shows a worse long-term mortality for women with two cancers than that with BC only. However, the increase in mortality was lower than expected under the additivity assumption.</p

Factors Determining Nestedness in Complex Networks

Understanding the causes and effects of network structural features is a key task in deciphering complex systems. In this context, the property of network nestedness has aroused a fair amount of interest as regards ecological networks. Indeed, Bastolla et al. introduced a simple measure of network nestedness which opened the door to analytical understanding, allowing them to conclude that biodiversity is strongly enhanced in highly nested mutualistic networks. Here, we suggest a slightly refined version of such a measure of nestedness and study how it is influenced by the most basic structural properties of networks, such as degree distribution and degree-degree correlations (i.e. assortativity). We find that most of the empirically found nestedness stems from heterogeneity in the degree distribution. Once such an influence has been discounted – as a second factor – we find that nestedness is strongly correlated with disassortativity and hence – as random networks have been recently found to be naturally disassortative – they also tend to be naturally nested just as the result of chance.This work was supported by Junta de Andalucia projects FQM-01505 and P09-FQM4682, and by Spanish MEC-FEDER project FIS2009-08451. S.J. is grateful for financial support from the European Commision under the Marie Curie Intra-European Fellowship Programme PIEF-GA-2010-276454

Multiple primary tumours: incidence estimation in the presence of competing risks

<p>Abstract</p> <p>Background</p> <p>Estimating the risk of developing subsequent primary tumours in a population is difficult since the occurrence probability is conditioned to the survival probability.</p> <p>Methods</p> <p>We proposed to apply Markov models studying the transition intensities from first to second tumour with the Aalen-Johansen (AJ) estimators, as usually done in competing risk models. In a simulation study we applied the proposed method in different settings with constant or varying underlying intensities and applying age standardisation. In addition, we illustrated the method with data on breast cancer from the Piedmont Cancer Registry.</p> <p>Results</p> <p>The simulation study showed that the person-years approach led to a sensibly wider bias than the AJ estimators. The largest bias was observed assuming constantly increasing incidence rates. However, this situation is rather uncommon dealing with subsequent tumours incidence. In 9233 cases with breast cancer occurred in women resident in Turin, Italy, between 1985 and 1998 we observed a significant increased risk of 1.91 for subsequent cancer of corpus uteri, estimated with the age-standardised Aalen-Johansen incidence ratio (AJ-IR^stand), and a significant increased risk of 1.29 for cancer possibly related to the radiotherapy of breast cancer. The peak of occurrence of those cancers was observed after 8 years of follow-up.</p> <p>Conclusion</p> <p>The increased risk of a cancer of the corpus uteri, also observed in other studies, is usually interpreted as the common shared risk factors such as low parity, early menarche and late onset of menopause. We also grouped together those cancers possibly associated to a previous local radiotherapy: the cumulative risk at 14 years is still not significant, however the AJ estimators showed a significant risk peak between the eighth and the ninth year. Finally, the proposed approach has been shown to be reliable and informative under several aspects. It allowed for a correct estimation of the risk, and for investigating the time trend of the subsequent cancer occurrence.</p