Opportunities for Transmission Power Control Protocols in Wireless Sensor Networks

This study investigates the opportunities for transmission power control (TPC) protocols in resource constrained wireless sensor networks (WSNs). The paper begins by creating a generalised model to describe the relationship between transmission power, communication reliability and energy consumption. Applying this model to the performance of state-of-the art radio hardware, the maximum potential energy savings achievable through the implementation of a TPC protocol are identified. From this, previous assumptions about the limited impact of protocols and mechanisms, such as TPC, which seek to reduce the energy consumed by wireless communication activities through targeting the distance dependent term are disproven. This paper concludes by presenting guidelines on the link conditions which offer the greatest opportunities for a TPC protocol

A Survey of Link Quality Properties Related to Transmission Power Control Protocols in Wireless Sensor Networks

Transmission Power Control (TPC) protocols are poised for wide spread adoption in wireless sensor networks (WSNs) to address energy constraints. The link quality properties that need to be captured in order to identify the optimum transmission power (TP) have not been clearly defined and previous works have presented conflicting views on the matter. This has led to several current TPC protocols using vastly different link quality properties and reporting unreliable, unstable and inefficient network performance. In this work, observations from several empirical studies on low-power wireless links are applied to identify the most critical properties of link quality for a TPC protocol. Comparing the requirements against currently available link quality estimators, it is shown that link quality estimation in WSNs is still very much an open challenge and one that must be addressed in order to implement an accurate and reliable TPC protocol

Seesaw mechanism in the sneutrino sector and its consequences

The seesaw-extended MSSM provides a framework in which the observed light neutrino masses and mixing angles can be generated in the context of a natural theory for the TeV-scale. Sneutrino-mixing phenomena provide valuable tools for connecting the physics of neutrinos and supersymmetry. We examine the theoretical structure of the seesaw-extended MSSM, retaining the full complexity of three generations of neutrinos and sneutrinos. In this general framework, new flavor-changing and CP-violating sneutrino processes are allowed, and are parameterized in terms of two $3\times 3$ matrices that respectively preserve and violate lepton number. The elements of these matrices can be bounded by analyzing the rate for rare flavor-changing decays of charged leptons and the one-loop contribution to neutrino masses. In the former case, new contributions arise in the seesaw extended model which are not present in the ordinary MSSM. In the latter case, sneutrino--antisneutrino mixing generates the leading correction at one-loop to neutrino masses, and could provide the origin of the observed texture of the light neutrino mass matrix. Finally, we derive general formulae for sneutrino--antisneutrino oscillations and sneutrino flavor-oscillations. Unfortunately, neither oscillation phenomena is likely to be observable at future colliders.Comment: 69 pages, 5 figures, uses axodraw.sty. Version accepted for publication in JHEP: some comments and one more Appendix with additional discussion added, references update

Incidental cardiac findings on computed tomography imaging of the thorax

<p>Abstract</p> <p>Background</p> <p>Investigation of pulmonary pathology with computed tomography also allows visualisation of the heart and major vessels. We sought to explore whether clinically relevant cardiac pathology could be identified on computed tomography pulmonary angiograms (CTPA) requested for the exclusion of pulmonary embolism (PE). 100 consecutive CT contrast-enhanced pulmonary angiograms carried out for exclusion of PE at a single centre were assessed retrospectively by two cardiologists.</p> <p>Findings</p> <p>Evidence of PE was reported in 5% of scans. Incidental cardiac findings included: aortic wall calcification (54%), coronary calcification (46%), cardiomegaly (41%), atrial dilatation (18%), mitral annulus calcification (15%), right ventricular dilatation (11%), aortic dilatation (8%) and right ventricular thrombus (1%). Apart from 3 (3%) reports describing cardiomegaly, no other cardiac findings were described in radiologists' reports. Other reported pulmonary abnormalities included: lung nodules (14%), lobar collapse/consolidation (8%), pleural effusion (2%), lobar collapse/consolidation (8%), emphysema (6%) and pleural calcification (4%).</p> <p>Conclusions</p> <p>CTPAs requested for the exclusion of PE have a high yield of cardiac abnormalities. Although these abnormalities may not have implications for acute clinical management, they may, nevertheless, be important in long-term care.</p

Galaxy clusters in X-rays: the buildup of massive structures in the last 10 Gyrs, and CHEX-MATE

The Italian community working on galaxy clusters proposed a coherent project to fully exploit both the proprietary and archival X-ray data of objects resolved spatially up to redshift 1.5. The project involved collaborative activities to address, in a synergetic exploitation of proprietary, archival and simulated data, the following goals: (i) the reconstruction of the gas density, temperature and metal abundance profiles in well-selected samples of clusters; (ii) to constrain with unprecedented accuracy the total and gas mass 3D distribution; (iii) the study of the accretion phenomena in the outskirts; (iv) detailed analyses of the ICM properties in the cores and their physical link with the nuclear activity in the central galaxies, also as function of the cosmic epoch; (v) the comparison between these observational constraints and the predictions from dedicated analytic models and hydrodynamical simulations. In this context, we started a new, unique project based on the collection, reduction, analysis and full scientific exploitation of the X-ray data of one of the only 2 AO-17 XMM-Newton "Multi-Year Heritage" programmes granted, CHEX-MATE