1,441 research outputs found
Reliable Reputation-Based Event Detection in V2V Networks
No full textTechnological advances in automotive and vehicle-to-vehicle communication paradigms promise the implementation of increasingly advanced services to make driving safer and more aware of events such as traffic congestion and road hazards. The detection and dissemination of reliable information about road events is of paramount importance to avoid unpleasant and potentially dangerous situations caused by the dissemination of false messages from unreliable or intentionally tampered vehicles. This paper proposes an event detection system based on reliable data dissemination, exploiting a fully distributed reputation and trust mechanism. Experiments conducted on a dataset containing realistic vehicle tracks on real-world maps demonstrate the system’s ability to withstand the presence of up to 30% of attackers orchestrated to propagate false events without significant performance degradation
Vitamin D deficiency is associated with type 2 diabetes mellitus in HIV infection.
No full textBACKGROUND: Metabolic complications, including type 2 diabetes mellitus and metabolic syndrome, are increasingly recognized among HIV-infected individuals. Low vitamin D levels increase the risk of type 2 diabetes mellitus, and vitamin D supplementation has been shown to decrease the risk of type 2 diabetes mellitus in patients without HIV infection.OBJECTIVES: The primary objective was to determine whether vitamin D deficiency (serum 25-hyrdoxyvitamin D <20 ng/ml) was associated with type 2 diabetes mellitus among HIV-infected patients. Our secondary objective was to determine whether vitamin D deficiency was associated with metabolic syndrome in HIV.METHODS: We conducted a cross-sectional study among participants enrolled in the prospective Modena (Italy) HIV Metabolic Clinic Cohort. Clinical and laboratory data, including history of type 2 diabetes mellitus, fasting blood glucose, components of metabolic syndrome, and 25-hydroxyvitamin D levels, were obtained for all participants.RESULTS: After adjusting for vitamin D supplementation, sex, age, body mass index, and hepatitis C virus co-infection, vitamin D deficiency was associated with type 2 diabetes mellitus [adjusted odds ratio (OR) 1.85; 95% confidence interval (CI) 1.03-3.32; P = 0.038]. The association between vitamin D deficiency and metabolic syndrome was not significant after adjusting for vitamin D supplementation, sex, age and body mass index (adjusted OR 1.32; 95% CI 1.00-1.75; P = 0.053).CONCLUSIONS: Our study demonstrates an association between vitamin D deficiency and type 2 diabetes mellitus. Clinical trials are needed to better characterize the association between vitamin D deficiency and type 2 diabetes mellitus in HIV infection and to evaluate whether vitamin D is able to prevent or delay the onset of type 2 diabetes mellitus
Viral hepatitis is associated with reduced bone mineral density in HIV-infected women but not men.
No full textOBJECTIVE:: Few studies have examined the impact of viral hepatitis on bone mineral density (BMD), and none have done so among HIV-infected patients. Our objective was to determine whether viral hepatitis was associated with low BMD in HIV. DESIGN:: A cross-sectional study among 1237 HIV-infected patients (625 with viral hepatitis). METHODS:: Dual-energy X-ray absorptiometry scans of the lumbar spine and femoral neck were obtained. Clinical data, hepatitis B and C status, and markers of bone metabolism were determined at dual-energy X-ray absorptiometry scanning. Multivariable logistic regression examined the association between hepatitis and low BMD (Z-scor
Influence of groundwater temperature variation on thermal plume modelling in geothermal open loop systems
No full textThe Groundwater Heat Pump system is a technology that withdraws water from a well or surface water, passes it through a heat exchanger and discharges the water into an injection well or nearby river, developing a thermal plume of colder/warmer re-injected water, known as the Thermal Affected Zone (TAZ). Plumes are considered a potential anthropogenic geothermal resource or pollution, in fact they might pose a risk to groundwater use downgradient. It is then important to know early in the project whether the aquifer is suitable for the system to be implemented and whether the TAZ will interfere with existing wells, subsurface infrastructure or land use. Physical processes affecting heat transport within an aquifer include advection (or convection), mechanical dispersion and diffusion (Diao et al., 2004). Plume propagation occurs primarily through advection (Lo Russo and Taddia, 2010), and tends to "degrade" following conductive heat transport, and convection within moving water (Hecht-Mendez et al., 2010). The results of a sensitive analysis realized by Lo Russo et al. (2012) indicates that the main hydrodynamic parameters that influence the heat transport are hydraulic conductivity and gradient. As the hydraulic conductivity varies according to the temperature due to the variation of the water dynamic viscosity, in the present study we evaluate the influence on heat transport of the groundwater temperature variation induced by an open-loop system reinjection system. To investigate this topic a sensitive analysis has been realized using FEFLOW® 6.2 package developed by Diersch (2010). FEFLOW gives the possibility to include or disregard the dynamic viscosity variation related to the groundwater temperature and therefore we simulated these two scenarios. For each of them nine different cases have been considered using the combination between three different conductivity classes and three different injection temperatures values. For each case (K-Treinj) the isotherms obtained in both scenarios have been compared geometrically. The two scenarios analysed highlighted that the variation of the dynamic viscosity with the groundwater temperature affects the extension of the TAZ in the cases of higher values of aquifer hydraulic conductivity and/or in the situations of warmer injected water and therefore in these modelling contexts it should be taken into account to correctly assess the subsurface thermal perturbation. References Diao N, Li Q, Fang Z. 2004. Heat transfer in ground heat exchangers with groundwater advection. Int. J. Thermal Sci., 43: 1203-1211. Diersch H.J.G. 2010. FEFLOW 6 - User's Manual. WASY GmbH, Berlin. Hecht-Mendez J, Molina-Giraldo N, Blum P, Bayer P (2010) Evaluating MT3DMS for heat transport simulation of closed geothermal systems. Ground Water 48(5), 741-756. Lo Russo S. and Taddia G. 2010. Advective heat transport in an unconfined aquifer induced by the field injection of an open-loop groundwater heat pump. American Journal of Environmental Sciences 6(3), 253-259 DOI: 10.3844/ajessp.2010.253.259. Lo Russo S, Taddia G, Verda V. 2012. Development of the thermally affected zone (TAZ) around a ground water heat pump (GWHP) system: a sensitivity analysis. Geothermics 43:66- 74. doi:10.1016/j.geothermics.2012.02.001
Dialogical Skirmishes
No full textTan was guest editor for 'And Now China?', a special print edition of the Ctrl+P journal, which critically responded to the celebratory rhetoric’s of ‘China Now’ and other celebratory markers of China's global ascent in 2008. As well as the introductory article 'Dialogical Skirmishes', Tan also interviewed Hans Ulrich Obrist
Administration of a novel plant extract product via drinking water to post-weaning piglets : effects on performance and gut health
No full textThe present study evaluated the effects of a novel plant extract (PE) product (GrazixTM) on the performance and gut health of
weaned piglets challenged with Escherichia coli. The PE was a standardised mixture of green tea leaves (Camellia sinensis) and
pomegranate fruit (Punica granatum) obtained by using the LiveXtractTM process. A total of 144 piglets were weaned at 24 days
and allocated to 8 for a 35-day experiment with a 2 × 2 × 2 factorial design comparing different treatments (water without product
(CT) or 8 μl/kg per day PE in drinking water (PE)), feeding regimens (ad libitum (AD) or restricted (RE)) and oral E. coli challenges
on day 9 (sham (− ) or infected ( +)). There were six pens per group with three piglets per pen. On day 35, 24 of the RE feeding
piglets were slaughtered. It was found that PE supplementation increased the average daily gain (ADG) from day 28 to day 35
( P =0.03) and increased the gain to feed ratio (G : F) from day 7 to day 14 ( P = 0.02). RE feeding led to lower feed intake in
piglets during the 1st week ( P<0.01), 2nd week ( P = 0.06), 3rd week ( P = 0.05), and throughout the course of the overall study
period ( P = 0.05). E. coli challenge decreased the ADG and G : F ratio from day 7 to day 14 ( P = 0.08 and <0.01, respectively)
and increased the faecal score (higher values indicate more severe diarrhoea) on days 14, 21, 28 and 35 ( P<0.01). PE
supplementation decreased the faecal score in the challenged piglets during the 1st week post-challenge ( P<0.01). E. coli
challenge increased the faecal E. coli level on day 14 ( P = 0.03) and increased the Enterobacteriaceae level on day 35 ( P<0.01).
Reduced faecal E. coli was observed on days 14 and 35 ( P = 0.05 and 0.02, respectively), and reduced Enterobacteriaceae
( P<0.01) was found on day 35 in the PE animals. RE feeding increased the faecal Lactobacillus, Enterobacteriaceae and
E. coli levels on day 35 ( P = 0.02, <0.01 and <0.01, respectively). These results suggest that PE supplementation may improve
the gut health status of post-weaning piglets and counteract some of the negative effects that occur when piglets are challenged
with E. coli
Concept of climate-charged airspace areas
No full textApproximately two third of aviation’s climate impact is caused by non-CO2 effects, like the production of ozone and the formation of contrail-cirrus clouds, which can be effectively prevented by re-routing flights around highly climate-sensitive areas. Although climate-optimized re-routing results in slightly longer flight times, increased fuel consumption and higher operating costs, it is up to 60% more climate-friendly. However, if mitigation efforts are associated with a direct increase in costs, this immediately raises the question of the willingness of primarily profit-oriented airlines to act in a more climate-friendly manner and the passengers´ willingness to pay for environmental protection. In order to create an incentive for climate-optimized flying, a climate charge is imposed on airlines when operating in these areas. If climate-charged airspaces (CCAs) are (partly) bypassed, both climate impact and operating costs of a flight can be reduced: a more climate-friendly routing becomes economically attractive (explanation video). By implementing the precautionary and polluter-pays principles of environmental economics, the concept introduces key requirements of a sustainable development into the field of aviation. The proposed extension of the accounting system clearly reduces the discrepancy between the marginal costs estimated by the airlines and the consequential costs for society. Accordingly, this resolves the trade-off between economic viability and environmental compatibility and creates a financial incentive for climate mitigation. The feasibility of this concept is demonstrated on a small route network in the North Atlantic flight corridor (NAFC). If flights are completely re-routed around altered CCAs, on average more than 90 % of the mitigation potential of climate-optimized flying is achieved.Aircraft Noise and Climate Effect
Longitudinal evidence of the impact of normal thyroid stimulating hormone variations on cognitive functioning in very old age
No full textThe purpose of this study was to examine longitudinal associations among thyroid stimulating hormone (TSH) levels and cognitive performance. Data collected at the first three assessment times, approximately 3 years apart, are reported for the survivors (n=45) from a previously published cross-sectional study. Participants were aged 75–93 years at baseline, and data reported were collected in the Kungsholmen Project, a longitudinal project investigating aging and dementia. Analyses revealed that although declining verbal fluency and visuospatial abilities were accompanied by simultaneously declining TSH levels, the pattern of cross-sectional and longitudinal results are interpreted such that declining TSH levels may have caused episodic memory deficits later on. These results were obtained in the examination of 6-year but not 3-year change, and after removal of the cognitive variation associated with depressive mood symptoms
A Philosophical commentary on Cicero, academica priora II 1-62.
No full textPhDIn confining this Commentary to the first 62 sections of the Lucullus
my intention has been to make a special study of Antiochus' case against the
Academic sceptics. Although this is the only full-length counter-argument
against Academic scepticism which we possess (despite the many works written
by both aides in a controversy spanning more than two centuries), due attention
has not been paid to it. Scholars have tended to use Cicero's work as a
source-book for Antiochus' general philosophical views or to confine their
attention to the sceptic case. Even if consideration has been given to the
dogmatic case as well (as by Stough, Greek Skepticism), there has been a
certain bias in favour of the Academic sceptics. This is possibly due to the
fact that the scepticism of the Academy has in itself a strong appeal and
that it has the final word in Cicero's work. But I do not think that Lucullus'
arguments, whatever their shortcomings, are weaker by comparison.
The Lucullus is, not only an extremely important philosophical text,
it is also one of the most difficult. Reid's Commentary is very valuable
but his interest was more literary and general than strictly philosophical.
My own Commentary is concerned solely with the philosophical content of the
dialogue and takes account of relevant work on Hellenistic philosophy since
Reid's edition appeared at the end of the last century, I have tried to
place the arguments and philosophical issues in their ancient context, either,
by means of plausible inferences where direct evidence is lacking or by
reference to classical texts. I am aware that the problem of knowledge is
still an issue today and I have made use of some modern works on the subject,
in elucidating particular arguments, but, in general, I have limited references
to modern philosophy to a minimum in order not to impede understanding of
Cicero's text and not to widen excessively the scope of the Commentary. The
text used is that of Plasborg (Teubner, Leipzig, 1922)
Study of compositional and luminescence properties of calcite in lapis lazuli for provenance investigations of archaeological findings
No full textIn this study, calcite crystals within 42 lapis lazuli reference rocks coming from four distinct mining regions (in present-day Afghanistan, Tajikistan, Siberia and Myanmar) were characterised in terms of their compositional and luminescence properties in order to identify potential provenance markers. A non-destructive approach based on Ion Beam Analysis was employed, in particular using mu-Particle Induced X-rays Emission (mu-PIXE) and mu-Ion Beam Induced Luminescence (mu-IBIL). The results indicate that calcite crystals in Afghan rocks are characterised by the highest quantity of Mg and Mn; whereas, Siberian calcite exhibit the highest Sr content. The application of Principal Component Analysis also enhanced the possibility of discriminating between the Myanmar and Tajik rocks, as well as between the four provenances in general, by exploiting the compositional variability of Mg, Mn, Sr and Y elements. Regarding the luminescence properties, notable differences in the intensity ratio between the 360 nm and the 620 nm luminescence bands were detected among the provenances. In the second part of this study, the new results were employed to infer the origin of the raw material of certain archaeological findings discovered in two different historical sites: four lapis lazuli fragments from Shahr-i Sokhta (Iran, 3rd millennium BCE) and a lapis lazuli tessera from the city of Tanis (Egypt, 1050-700 BCE). The results of the analysis indicate that, among the four provenances considered in the reference rocks database, the best compatibility of the data from both case studies is found with the Afghan dataset. This suggests that the area of Afghanistan is the most probable source for the raw materials of the investigated findings
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