Security in Wireless Sensor Networks: Issues and Challenges

Wireless Sensor Network (WSN) is an emerging technology that shows great promise for various futuristic applications both for mass public and military. The sensing technology combined with processing power and wireless communication makes it lucrative for being exploited in abundance in future. The inclusion of wireless communication technology also incurs various types of security threats. The intent of this paper is to investigate the security related issues and challenges in wireless sensor networks. We identify the security threats, review proposed security mechanisms for wireless sensor networks. We also discuss the holistic view of security for ensuring layered and robust security in wireless sensor networks.Comment: 6 page

Evaluation of polymer coated attenuated total reflection (ATR) elements for the analysis of organic compounds in aqueous solution

A significant limitation of ATR/FTIR for the analysis of aqueous solutions is the relatively high bulk concentration of analyte required. One approach to improving the detection of an analyte is to incorporate a thin polymeric phase at the surface of the ATR element. The purpose of the polymeric phase is to extract the analyte of interest and concentrate it within the depth of penetration of the evanescent wave. Utilizing a very high molecular weight poly(vinyl chloride) phase the time necessary to reach equilibrium for a 0.05% (v/v) nitrobenzene in a 1.5% (w/v) methanol/water solution was over 60 minutes. A study was undertaken to determine if incorporating a plasticizer into the polymeric phase reduces the time required to reach the maximum level of absorbance achieved for the analyte. Specifically, the ability of phases which are mixtures of PVC and chloroparaffin plasticizers to concentrate analytes from aqueous solutions has been investigated. The results indicate that incorporating chloroparaffin into a PVC phase reduces the time required to reach the maximum absorbance for the analyte in an aqueous solution containing 1.5% methanol by approximately 45%. The addition of chloroparaffin also results in an increase in the absorbance observed for the analytes investigated in this study. Commercially available untapered and tapered chalcogenide fibers have been coated with poly(vinyl chloride) with plasticizer. These coated fibers were exposed to various analytes. All organic analytes provided readily detectable signals with the coated fibers but were not observable when the aqueous solution was sampled with the use of uncoated fibers. The results confirm the advantages of using a polymer coating to concentrate the analyte and reduced the water background for detecting non polar organic solutes in aqueous solutions

X-Ray and Infrared Enhancement of Anomalous X-ray Pulsar 1E 2259+58

The long term (~1.5 years) X-ray enhancement and the accompanying infrared enhancement light curves of the anomalous X-ray pulsar 1E 2259+58 following the major bursting epoch can be accounted for by the relaxation of a fall back disk that has been pushed back by a gamma-ray flare. The required burst energy estimated from the results of our model fits is low enough for such a burst to have remained below the detection limits. We find that an irradiated disk model with a low irradiation efficiency is in good agreement with both X-ray and infrared data. Non-irradiated disk models also give a good fit to the X-ray light curve, but are not consistent with the infrared data for the first week of the enhancement.Comment: 17 pages, 3 figures, accepted for publication in Ap

Space--time fluctuations and the spreading of wavepackets

Using a density matrix description in space we study the evolution of wavepackets in a fluctuating space-time background. We assume that space-time fluctuations manifest as classical fluctuations of the metric. From the non-relativistic limit of a non-minimally coupled Klein-Gordon equation we derive a Schr\"odinger equation with an additive gaussian random potential. This is transformed into an effective master equation for the density matrix. The solutions of this master equation allow to study the dynamics of wavepackets in a fluctuating space-time, depending on the fluctuation scenario. We show how different scenarios alter the diffusion properties of wavepackets.Comment: 11 page

Metric fluctuations and decoherence

Recently a model of metric fluctuations has been proposed which yields an effective Schr\"odinger equation for a quantum particle with a modified inertial mass, leading to a violation of the weak equivalence principle. The renormalization of the inertial mass tensor results from a local space average over the fluctuations of the metric over a fixed background metric. Here, we demonstrate that the metric fluctuations of this model lead to a further physical effect, namely to an effective decoherence of the quantum particle. We derive a quantum master equation for the particle's density matrix, discuss in detail its dissipation and decoherence properties, and estimate the corresponding decoherence time scales. By contrast to other models discussed in the literature, in the present approach the metric fluctuations give rise to a decay of the coherences in the energy representation, i. e., to a localization in energy space.Comment: 7 page

An online survey of perimenopausal women to determine their attitudes and knowledge of the menopause

INTRODUCTION: Women are not usually taught about the menopause formally, and many general practitioners have relatively little training. The aim of this study was to explore perimenopausal women's attitudes and knowledge of the menopause. METHOD: An online survey was designed to evaluate attitudes and knowledge of the menopause in women older than 40 years. The survey was generated with Qualtrics XM® and promoted via social media. In all, 3150 women started the survey. In this study, data from 947 perimenopausal women were analysed. RESULTS: Regarding women's attitudes to the menopause, 38.8% were accepting of it but more than 30% were dreading it. The women had experienced a number of menopause symptoms including mood swings (68.9%), brain fog (68.3%), and fatigue (66.8%). More than 90% of women had never been taught about the menopause at school, and more than 60% did not feel informed at all about the menopause. School was thought to be the best place for menopause education to start (83.6%). In all, 68.2% of women had only looked for information about the menopause as their symptoms started and they had talked to friends and used a variety of websites to look for information. When asked for their free-text views on the menopause, thematic analysis produced four themes: the overarching knowledge gap, the onset and impact of symptoms, perimenopause: the hidden phenomenon, and managing symptoms: differing schools of thought. CONCLUSION: Lack of education for women and their general practitioners is causing perimenopausal women to go through this important stage in their lives with a lack of knowledge and appropriate medical care. It is essential that women are taught about the menopause, from school onwards and that we offer health professionals appropriate training starting from the medical school curriculum

Dim Isolated Neutron Stars, Cooling and Energy Dissipation

The cooling and reheating histories of dim isolated neutron stars(DINs) are discussed. Energy dissipation due to dipole spindown with ordinary and magnetar fields, and due to torques from a fallback disk are considered as alternative sources of reheating which would set the temperature of the neutron star after the initial cooling era. Cooling or thermal ages are related to the numbers and formation rates of the DINs and therefore to their relations with other isolated neutron star populations. Interaction with a fallback disk, higher multipole fields and activity of the neutron star are briefly discussed.Comment: To appear in Astrophysics and Space Science, in the proceedings of the conference "Isolated Neutron Stars: from the Interior to the Surface", London, April 2006; eds. D. Page, R. Turolla and S. Zane. Revised version: with minor change and typos correcte

Assessment of procedure related anxiety and depression in oncologic patients before F-18 FDG PET-CT imaging

Background: The aim of this study was to study objectively the level of anxiety and depression in patients undergoing positron emission tomography-computed tomography (PET-CT).One hundred and forty four oncologic out-patients (76 male, 68 female) were included in this study. Methods: All patients were referred to Nuclear Medicine Department for Fluorine-18 fluorodeoxyglucose (F-18 FDG) PET-CT imaging for the assessment of their malignant or possibly malignant diseases. The Hospital Anxiety Depression Scale and the State and Trait Anxiety Inventory I and II were used to evaluate the anxiety and depression levels in these patients. Results: The mean anxiety and depression scores of The Hospital Anxiety Depression Scale prior to F-18 FDG PET-CT were 9.2 ( ± 3.8) and 6.6 ( ± 3.4), respectively. The mean state and trait anxiety scores of the State and Trait Anxiety Inventory I and II prior to F-18 FDG PET-CT were 40.4 (± 8.5) and 46.62 ± 7.8, respectively. The Hospital Anxiety Depression Scale and the State and Trait Anxiety Inventory I and II anxiety scores were found to be significantly higher in female patients, smokers and in patients with higher stage disease. Conclusion: Our results suggest that F-18 FDG PET-CT imaging may at least contribute to patient's baseline anxiety which is already generated by being an oncology patient, and thus nuclear medicine physicians should handle the patients with extra care to minimize this affect. © 2015, Umut Elboga, et al

Metric fluctuations and the Weak Equivalence Principle

We describe space--time fluctuations by means of small fluctuations of the metric on a given background metric. From a minimally coupled Klein--Gordon equation we obtain within a weak-field approximation up to second order and an averaging procedure over a finite space--time scale given by the quantum particle in the non--relativistic limit a modified Schr\"odinger equation. The dominant modification consists in an anomalous inertial mass tensor which depends on the type of particle and on the fluctuation scenario. The scenario considered in this paper is a most simple picture of spacetime fluctuations and gives an existence proof for an apparent violation of the weak equivalence principle and, in general, for a violation of Lorentz invariance.Comment: 10 pages, to appear in Class. Quantum Grav. (2008