507 research outputs found
Security Patterns for Agent Systems
Security patterns capture the experiences of experts, allowing novices to rely on expert knowledge and solve security problems in a more systematic and structured way. So far, literature provides many examples of security patterns for object-oriented systems. However, no attempt has been made to document security patterns for multiagent systems. In this paper we present a set of patterns for secure agent systems that, currently, consisting of four patterns
Dissipative dynamics in a quantum register
A model for a quantum register dissipatively coupled with a bosonic thermal
bath is studied. The register consists of qubits (i.e. spin degrees
of freedom), the bath is described by bosonic modes. The register-bath
coupling is chosen in such a way that the total number of excitations is
conserved. The Hilbert space splits allowing the study of the dynamics
separately in each sector. Assuming that the coupling with the bath is the same
for all qubits, the excitation sectors have a further decomposition according
the irreducible representations of the spin algebra. The stability
against environment-generated noise of the information encoded in a quantum
state of the register depends on its symmetry content. At zero
temperature we find that states belonging to the vacuum symmetry sector have
for long time vanishing fidelity, whereas each lowest spin vector is decoupled
from the bath and therefore is decoherence free. Numerical results are shown in
the one-excitation space in the case qubit-dependent bath-system coupling.Comment: to appear on Phys. Rev. A, 8 pages + 5 postscript figure
Impact of altitude on power output during cycling stage racing
Purpose The purpose of this study was to quantify the effects of moderate-high altitude on power output, cadence, speed and heart rate during a multi-day cycling tour. Methods Power output, heart rate, speed and cadence were collected from elite male road cyclists during maximal efforts of 5, 15, 30, 60, 240 and 600 s. The efforts were completed in a laboratory power-profile assessment, and spontaneously during a cycling race simulation near sea-level and an international cycling race at moderate-high altitude. Matched data from the laboratory power-profile and the highest maximal mean power output (MMP) and corresponding speed and heart rate recorded during the cycling race simulation and cycling race at moderate-high altitude were compared using paired t-tests. Additionally, all MMP and corresponding speeds and heart rates were binned per 1000m (3000m) according to the average altitude of each ride. Mixed linear modelling was used to compare cycling performance data from each altitude bin. Results Power output was similar between the laboratory power-profile and the race simulation, however MMPs for 5â600 s and 15, 60, 240 and 600 s were lower (p †0.005) during the race at altitude compared with the laboratory power-profile and race simulation, respectively. Furthermore, peak power output and all MMPs were lower (â„ 11.7%, p †0.001) while racing \u3e3000 m compared with rides completed near sea-level. However, speed associated with MMP 60 and 240 s was greater (p \u3c 0.001) during racing at moderate-high altitude compared with the race simulation near sea-level. Conclusion A reduction in oxygen availability as altitude increases leads to attenuation of cycling power output during competition. Decrement in cycling power output at altitude does not seem to affect speed which tended to be greater at higher altitude
Geometry of perturbed Gaussian states and quantum estimation
We address the nonGaussianity (nG) of states obtained by weakly perturbing a
Gaussian state and investigate the relationships with quantum estimation. For
classical perturbations, i.e. perturbations to eigenvalues, we found that nG of
the perturbed state may be written as the quantum Fisher information (QFI)
distance minus a term depending on the infinitesimal energy change, i.e. it
provides a lower bound to statistical distinguishability. Upon moving on
isoenergetic surfaces in a neighbourhood of a Gaussian state, nG thus coincides
with a proper distance in the Hilbert space and exactly quantifies the
statistical distinguishability of the perturbations. On the other hand, for
perturbations leaving the covariance matrix unperturbed we show that nG
provides an upper bound to the QFI. Our results show that the geometry of
nonGaussian states in the neighbourhood of a Gaussian state is definitely not
trivial and cannot be subsumed by a differential structure. Nevertheless, the
analysis of perturbations to a Gaussian state reveals that nG may be a resource
for quantum estimation. The nG of specific families of perturbed Gaussian
states is analyzed in some details with the aim of finding the maximally non
Gaussian state obtainable from a given Gaussian one.Comment: 7 pages, 1 figure, revised versio
Safety and Efficacy of Low Blood Pressures Among Patients With Diabetes Subgroup Analyses From the ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial)
ObjectivesWe sought to determine whether the blood pressure (BP) levels at which cardiovascular (CV) protection is achieved differ between diabetic and nondiabetic patients from the ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial).BackgroundGreater absolute benefits of BP reductions have been claimed for diabetic as compared with nondiabetic patients.MethodsA total of 25,584 patients (9,603 diabetic), older than 55 years, at high CV risk were randomized to ramipril, telmisartan, or both and observed for 4.6 years. We pooled the treatment arms to examine the relationships between BP and the primary composite outcome (CV death, nonfatal myocardial infarction or stroke, or hospitalized heart failure) and its components.ResultsThe primary outcome occurred in 1,938 (20.2%) diabetic patients and in 2,276 (14.2%) nondiabetic patients. Compared with nondiabetic patients, diabetic patients had a significantly higher risk for the primary endpoint (hazard ratio [HR]: 1.48; 95% confidence interval [CI]: 1.38 to 1.57) and CV death (HR: 1.56; 95% CI: 1.42 to 1.71); myocardial infarction (HR: 1.30 (95% CI: 1.17 to 1.46); stroke (HR: 1.39; 95% CI: 1.23 to 1.56); and congestive heart failure hospitalization (HR: 2.06; 95% CI: 1.82 to 2.32). The CV risk was significantly higher in diabetic than in nondiabetic patients regardless of the systolic BP changes during treatment. In both diabetic and nondiabetic patients, progressively greater systolic BP reductions were accompanied by reduced risk for the primary outcome only if baseline systolic BP levels ranged from 143 to 155 mm Hg; except for stroke, there was no benefit in fatal or nonfatal CV outcomes by reducing systolic BP below 130 mm Hg.ConclusionsThe relationship between BP and overall CV risk had a similar pattern in diabetic and nondiabetic patients over a wide range of baseline and in-treatment BP values although, for the same systolic BP, a higher risk is observed in diabetic patients. (Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial [ONTARGET]; NCT00153101
New Constraints on the Evolution of the Inner Northern Apennines by K-Ar Dating of Late Miocene-Early Pliocene Compression on the Island of Elba, Italy
The Northern Apennines (NA) orogenic wedge formed during Oligocene-Miocene convergence and westward subduction of Adria beneath the European Plate. Extension ensued in the Mid-Late Miocene in response to Adria roll-back, causing opening of the back-arc Northern Tyrrhenian Sea. Whether extension continues uninterrupted since the Mid-Late Miocene or it was punctuated by short-lived compressional events, remains, however, uncertain. We used the K-Ar method to date a set of brittle-ductile and brittle deformation zones from the Island of Elba to contribute to this debate. We dated the low-angle Zuccale Fault (ZF), the Capo Norsi-Monte Arco Thrust (CN-MAT), and the Calanchiole Shear Zone (CSZ). The CN-MAT and CSZ are moderately west dipping, top-to-the-east thrusts in the immediate footwall of the ZF. The CSZ slipped 6.14 ± 0.64 Ma (<0.1 Όm fraction) and the CN-MAT 4.90 ± 0.27 Ma ago (<0.4 Όm fraction). The ZF, although cutting the two other faults, yielded an older age of 7.58 ± 0.11 Ma (<0.1 Όm fraction). The ZF gouge, however, contains an illitic detrital contaminant from the Paleozoic age flysch deformed in its hanging wall and the age thus is a maximum faulting age. Removal of ~1% of a 300-Ma-old contaminant brings the ZF faulting age to <4.90 Ma. Our results provide the first direct dating of brittle deformation in the Apennines, constraining Late Miocene-Early Pliocene regional compression. They call for a refinement of current NA geodynamic models in the framework of the Northern Tyrrhenian Sea extension
Mendelian randomization study of adiposity-related traits and risk of breast, ovarian, prostate, lung and colorectal cancer
Background: Adiposity traits have been associated with risk of many cancers in observational studies, but whether these associations are causal is unclear. Mendelian randomization (MR) uses genetic predictors of risk factors as instrumental variables to eliminate reverse causation and reduce confounding bias. We performed MR analyses to assess the possible causal relationship of birthweight, childhood and adult body mass index (BMI), and waist-hip ratio (WHR) on the risks of breast, ovarian, prostate, colorectal and lung cancers. Methods: We tested the association between genetic risk scores and each trait using summary statistics from published genome-wide association studies (GWAS) and from 51 537 cancer cases and 61 600 controls in the Genetic Associations and Mechanisms in Oncology (GAME-ON) Consortium. Results: We found an inverse association between the genetic score for childhood BMI and risk of breast cancer [odds ratio (OR)=0.71 per standard deviation (s.d.) increase in childhood BMI; 95% confidence interval (CI): 0.60, 0.80; P=6.5Ă10-5). We also found the genetic score for adult BMI to be inversely associated with breast cancer risk (OR=0.66 per s.d. increase in BMI; 95% CI: 0.57, 0.77; P=2.5Ă10-7), and positively associated with ovarian cancer (OR=1.35; 95% CI: 1.05, 1.72; P=0.017), lung cancer (OR=1.27; 95% CI: 1.09, 1.49; P=2.9Ă10-3) and colorectal cancer (OR=1.39; 95% CI: 1.06, 1.82, P=0.016). The inverse association between genetically predicted adult BMI and breast cancer risk remained even after adjusting for directional pleiotropy via MR-Egger regression. Conclusions: Findings from this study provide additional understandings of the complex relationship between adiposity and cancer risks. Our results for breast and lung cancer are particularly interesting, given previous reports of effect heterogeneity by menopausal status and smoking status.</p
Is Wilms Tumor a Candidate Neoplasia for Treatment with WNT/ÎČ-Catenin Pathway Modulators?-A Report from the Renal Tumors Biology-Driven Drug Development Workshop
The European Network for Cancer Research in Children and Adolescents (ENCCA) consortium organized a workshop in Rome, in June 2012, on âRenal Tumor Biology Driven Drug Developmentâ to discuss the current knowledge in pediatric renal cancers and to recommend directions for further research. Wilms tumor (WT) is the most common renal tumor of childhood and represents a success of pediatric oncology, with cure rates of over 85% of cases. However, a substantial minority (~25%) responds poorly to current therapies and requires âhigh riskâ treatment or relapse. Moreover, the successfully treated majority are vulnerable to the late effects of treatment, with nearly one quarter reporting severe chronic health conditions by 25 years of follow up. Main purposes of this meeting were: to advance our understanding on the molecular drivers in WT, their heterogeneity and interdependencies; to provide updates on the clinic-pathologic associations with biomarkers; to identify eligible populations for targeted drugs; and to model opportunities to use preclinical model systems and prioritize targeted agents for early phase clinical trials. At least three different pathways are involved in WT; this review represents the outcome of the workshop discussion on the WNT/ÎČ-catenin pathway in Wilms tumorigenesis
Association between Adult Height and Risk of Colorectal, Lung, and Prostate Cancer:Results from Meta-analyses of Prospective Studies and Mendelian Randomization Analyses
Background: Observational studies examining associations between adult height and risk of colorectal, prostate, and lung cancers have generated mixed results. We conducted meta-analyses using data from prospective cohort studies and further carried out Mendelian randomization analyses, using height-associated genetic variants identified in a genome-wide association study (GWAS), to evaluate the association of adult height with these cancers. Methods and Findings: A systematic review of prospective studies was conducted using the PubMed, Embase, and Web of Science databases. Using meta-analyses, results obtained from 62 studies were summarized for the association of a 10-cm increase in height with cancer risk. Mendelian randomization analyses were conducted using summary statistics obtained for 423 genetic variants identified from a recent GWAS of adult height and from a cancer genetics consortium study of multiple cancers that included 47,800 cases and 81,353 controls. For a 10-cm increase in height, the summary relative risks derived from the meta-analyses of prospective studies were 1.12 (95% CI 1.10, 1.15), 1.07 (95% CI 1.05, 1.10), and 1.06 (95% CI 1.02, 1.11) for colorectal, prostate, and lung cancers, respectively. Mendelian randomization analyses showed increased risks of colorectal (odds ratio [OR] = 1.58, 95% CI 1.14, 2.18) and lung cancer (OR = 1.10, 95% CI 1.00, 1.22) associated with each 10-cm increase in genetically predicted height. No association was observed for prostate cancer (OR = 1.03, 95% CI 0.92, 1.15). Our meta-analysis was limited to published studies. The sample size for the Mendelian randomization analysis of colorectal cancer was relatively small, thus affecting the precision of the point estimate. Conclusions: Our study provides evidence for a potential causal association of adult height with the risk of colorectal and lung cancers and suggests that certain genetic factors and biological pathways affecting adult height may also affect the risk of these cancers.</p
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