Mechanism for a Decaying Cosmological Constant

A mechanism is introduced to reduce a large cosmological constant to a sufficiently small value consistent with observational upper limit. The basic ingradient in this mechanism is a distinction which has been made between the two unit systems used on cosmology and particle physics. We have used a conformal invariant gravitational model to define a particular conformal frame in terms of the large scale properties of the universe. It is then argued that the contributions of mass scales in particle physics to the vacuum energy density should be considered in a different conformal frame. In this manner a cancellation mechanism is presented in which the conformal factor plays a key role to relax the large effective cosmological constant.Comment: 6 pages, no figur

Hadamard States and Two-dimensional Gravity

We have used a two-dimensional analog of the Hadamard state-condition to study the local constraints on the two-point function of a linear quantum field conformally coupled to a two-dimensional gravitational background. We develop a dynamical model in which the determination of the state of the quantum field is essentially related to the determination of a conformal frame. A particular conformal frame is then introduced in which a two-dimensional gravitational equation is established.Comment: 7 pages, no figur

Mach's Principle and Model for a Broken Symmetric Theory of Gravity

We investigate spontaneous symmetry breaking in a conformally invariant gravitational model. In particular, we use a conformally invariant scalar tensor theory as the vacuum sector of a gravitational model to examine the idea that gravitational coupling may be the result of a spontaneous symmetry breaking. In this model matter is taken to be coupled with a metric which is different but conformally related to the metric appearing explicitly in the vacuum sector. We show that after the spontaneous symmetry breaking the resulting theory is consistent with Mach's principle in the sense that inertial masses of particles have variable configurations in a cosmological context. Moreover, our analysis allows to construct a mechanism in which the resulting large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure

Comparison of essential oil content and composition in two German chamomile (Matricaria chamomilla L.) genotypes

Two German chamomile genotypes (wild and domestic) were investigated for essential oil content and composition. Wild and domestic chamomile flowers were collected from Noor-Abad and Karaj regions and dried before essential oil extraction using distillation method. Essential oil components were identified by analytical gas-chromatography and mass spectrometry. Results revealed that essential oil efficiency in domestic and wild chamomile was recorded as 0.87 and 0.77%, respectively. Amongst fifteen different components identified in essential oil samples, (E)-â-farnesene, á -bisabolol oxide A and B and chamazulene were found to be the major components with frequency of 12.86, 31.86, 5.24 and 6.16% in domestic species and 8.83, 2.52, 1.81 and 55.606% in wild species. Irrespective of slight reduction in essential oil content and its components, wild German chamomile genotype can be used as valuable source in future domestication programmes

On Cosmological Implication of the Trace Anomaly

We establish a connection between the trace anomaly and a thermal radiation in the context of the standard cosmology. This is done by solving the covariant conservation equation of the stress tensor associated with a conformally invariant quantum scalar field. The solution corresponds to a thermal radiation with a temperature which is given in terms of a cut-off time excluding the spacetime regions very close to the initial singularity. We discuss the interrelation between this result and the result obtained in a two-dimensional schwarzschild spacetime.Comment: 8 pages, no figure

The effect of an exercise program on the health-quality of life in older adults

INTRODUCTION: An essential public health goal is to reduce age-related disabilities in the elderly. The present study aimed to investigate the effect of exercise program on health-quality of life (HQL) in older adults. METHODS: Subjects were sixty healthy adult volunteers over the age of �� years. None of the subjects had any experience in exercise programs but were physically active and able to perform activities of daily living independently. The subjects were randomly assigned into one of two groups each with �� people: test (exercise) group and control (no exercise) group. The test group was taken into a � - week aerobic exercise program. The exercises included a �- �� minute circulatory warm-up, a �� minute walking and a �-�� minute stretching/cool-down period. The exercises were performed three times per week under supervision of an experienced instructor. No exercise program was prescribed for the control group. Both groups were assessed before and after the exercise program. The LEIPAD questionnaire was used to measure HQL. RESULTS: The results showed significant improvements in all domains of the LEIPAD questionnaire whilst the level of HQL did not change and none of the scores obtained by the LEIPAD was significant. Measures of HQL improved with exercise so that there were no HQL changes in the control but significant changes were observed in the exercise group. CONCLUSION: This study suggests that an exercise program has resulted in a signific

Integron-Mediated Antibiotic Resistance in Acinetobacter baumannii Isolated from Intensive Care Unit Patients, Babol, North of Iran

Background. We investigated the integron types and their relation with antibiotic resistance among A. baumannii isolates collected from intensive care unit patients, Babol, north of Iran. Methods. In this cross-sectional study, a total of 73 bronchoalveolar lavage samples were obtained from patients in ICU. Susceptibility testing was performed by disk diffusion method. Types of integrons were identified by an integrase gene PCR. Results. In total, 47.9% A. baumannii isolates were recovered from the BAL samples. All isolates were resistant to ceftazidime. 91.4% and 58.3% of isolates were MDR and XDR, respectively. The rate of colistin resistance with the E-test was 5.7%. Molecular analysis of class I, II, and III integrons showed that 25.7%, 88.6%, and 28.6% of the isolates carried the intI, intII, and intIII genes, respectively. Discussion. Our results show that different classes of integrons are commonly spread among A. baumannii strains and these genomic segments can play an important role in the acquisition of MDR and XDR phenotypes. So monitoring drug resistance in A. baumannii isolates with the use of int gene PCR is very important to plan specific infection control measures to prevent the spread of MDR-AB and XDR-AB in Iran’s hospitals

Scalable Delivery of Stream Query Result

Continuous queries over data streams typically produce large volumes of result streams. To scale up the system, one should carefully study the problem of delivering the result streams to the end users, which, unfortunately, is often over-looked in existing systems. In this paper, we leverage Distributed Publish/Subscribe System (DPSS), a scalable data dissemination infrastructure, for efficient stream query result delivery. To take advantage of DPSS's multicast-like data dissemination architecture, one has to exploit the common contents among different result streams and maximize the sharing of their delivery. Hence, we propose to merge the user queries into a few representative queries whose results subsume those of the original ones, and disseminate the result streams of these representative queries through the DPSS. To realize this approach, we study the stream query containment theories and propose efficient query grouping and merging algorithms. The proposed approach is non-intrusive and hence can be easily implemented as a middleware to be incorporated into existing stream processing systems. A prototype is developed on top of an open- source stream processing system and results of an extensive performance study on real datasets verify the efficacy of the proposed techniques