We studied the Einstein-Brans-Dicke cosmology in detail. The difference of the evolution of the universe is significant between Einstein-Brans-Dicke cosmology and standard big-bang model during the radiation-dominated era. The power-law evolution of the scale factor is fast enough to solve the cosmological puzzles and slow enough to avoid the graceful exit problem. However, the constraints from...

String cosmology solutions are examined in a generalized phase-space including sources representing arbitrary corrections to lowest order string-dilatongravity effective action. We find a set of necessary conditions for a graceful exit transition from a dilaton-driven inflationary phase to a radiation dominated era. We show that sources allowing such a transition have to violate energy conditio...

What trajectory in the laboratory frame does a marble follow if it is held inside a freely rotating pipe and then suddenly released so that it can slide frictionlessly outward along the pipe? A previously published solution is only valid for a pipe of small moment of inertia (so that it is either low in mass or short in length). IOP

Firms can motivate workers by offering them social status. Much of the literature argues that a rise in status is a powerful work incentive while ignoring its impact on coordination. However, when workers need to collaborate while having individual vested interests, too large a difference in status distorts how workers coordinate, i.e., one worker compromises too much with respect to his most p...

INTRODUCTION Although water pipe tobacco smoking is common in Lebanon and Syria, prevalence in neighboring Jordan is uncertain. The purposes of this study were (a) to assess the prevalence of water pipe tobacco smoking among university students in Jordan and (b) to determine associations between sociodemographic variables and water pipe tobacco smoking in this population. METHODS A trained in...

BACKGROUND The objective of this study was to examine the association between tobacco smoking, in particular water pipe smoking, and periodontal health. METHODS A total of 262 citizens of Jeddah, Saudi Arabia in the age range from 17 to 60 years volunteered to participate in the study. The clinical examinations were carried out at King Faisal Specialty Hospital and Research Center in Jeddah a...

To compare the effect of various pipe materials on biofilm formation, surface water was used as the test water source; plastic-based pipe materials (polyvinyl chloride-PVC, unplasticised polyvinyl chloride-UPVC, medium density polyethylene-MDPE) and cement-based pipe materials (cement and asbestos cement) are commonly used in drinking water distribution systems in South Africa as test pipe mate...

Further, even though it is intellectually accepted that we have methodological means to combat these factors and provide benefits during the evolutionary process, development managers still choose short term goals over these long term benefits. Given a choice between getting a system out as early as possible and doing a proper design that will evolve gracefully, the first is invariably chosen a...

This document provides implementation guidelines for the use of return codes in RFC 3435, Media Gateway Control Protocol (MGCP) Version 1.0. Return codes in RFC 3435 do not cover all possible specific situations that may ever occur in a gateway. That is not possible and not necessary. What is important is to ensure that the Call Agent that receives a return code behaves appropriately and consis...

In the present study, non-Newtonian flow in annular pipe is considered. The analytical solution for velocity and temperature fields is presented while entropy generation due to fluid friction and heat transfer is formulated. The third grade fluid with constant properties is accommodated in the analysis. It is found that reducing non-Newtonian parameter increases maximum velocity magnitude and m...