The Cosmological Spacetime

We present here the transformations required to recast the Robertson-Walker metric and Friedmann-Robertson-Walker equations in terms of observer-dependent coordinates for several commonly assumed cosmologies. The overriding motivation is the derivation of explicit expressions for the radius R_h of our cosmic horizon in terms of measurable quantities for each of the cases we consider. We show that the cosmological time dt diverges for any finite interval ds associated with a process at R -> R_h, which therefore represents a physical limit to our observations. This is a key component required for a complete interpretation of the data, particularly as they pertain to the nature of dark energy. With these results, we affirm the conclusion drawn in our earlier work that the identification of dark energy as a cosmological constant does not appear to be consistent with the data.Comment: Accepted for publication in the IJMP-D; 13 page

Modeling Big Medical Survival Data Using Decision Tree Analysis with Apache Spark

In many medical studies, an outcome of interest is not only whether an event occurred, but when an event occurred; and an example of this is Alzheimer’s disease (AD). Identifying patients with Mild Cognitive Impairment (MCI) who are likely to develop Alzheimer’s disease (AD) is highly important for AD treatment. Previous studies suggest that not all MCI patients will convert to AD. Massive amounts of data from longitudinal and extensive studies on thousands of Alzheimer’s patients have been generated. Building a computational model that can predict conversion form MCI to AD can be highly beneficial for early intervention and treatment planning for AD. This work presents a big data model that contains machine-learning techniques to determine the level of AD in a participant and predict the time of conversion to AD. The proposed framework considers one of the widely used screening assessment for detecting cognitive impairment called Montreal Cognitive Assessment (MoCA). MoCA data set was collected from different centers and integrated into our large data framework storage using a Hadoop Data File System (HDFS); the data was then analyzed using an Apache Spark framework. The accuracy of the proposed framework was compared with a semi-parametric Cox survival analysis model

Photophysics of substituted [1,4]Benzodioxino[3,2-b]Oxanthrene (BDO) Chromophores and their macromolecules: a spectroscopy and density functional theory study.

Chromophores and macromolecules containing [1,4]benzodioxino[3,2-b]oxanthrene (BDO) has attracted attention since the beginning of this century. Previous studies demonstrated their potential in wide range of applications including gas permeability, hydrogen and energy storage, sensing, and catalysis. Better understanding of the geometrical and electronic structure characteristics of BOD-based chromophores is vital to advance their employment in these applications. This work utilizes spectroscopy techniques coupled with density functional theory methods to provide this required understanding. Substituted BDOs exhibit red-shift of \u3e1 eV in their electronic transitions compared to unsubstituted BDOs. This shift is explained by a molecular orbital reorganization induced by the substituents. Sulfonated BDOs exhibit folding in their backbone compared to the planar dicarbonitrile BDO (BDODC). The folding originates from an O···C interaction between the sulfonyl substitute and the backbone of the chromophore. Photoexcitated BDODC relaxes to its first singlet excited state (S1) in ∼3.8 ps. Fast inter-system crossing (ISC) deactivates S1 to the first triplet excited state (T1) in ∼63 ps. S1 also deactivates to the ground state (S0) through a photoluminescence (PL) process in ∼13 ns. Substituted BDOs retain their geometrical and electronic properties within the framework of the macromolecules. However, evidence suggests the presence of charge-transfer states (CTSs); rationalized by the Frenkel-Davydov exciton model. Theoretical methods indicate geometrical reorganization and charge redistribution associated with the lowest CTS. Spectroscopy methods reveal a relaxation to the S1 of the macromolecules in S1 deactivates through an ISC process in1 undergoes a fast charge-transfer to the CTS inps. Folding of sulfonated BDOs rationalizes the higher gas separation efficiency reported for their membranes. Additionally, the geometrical reorganizations of their excited states provide a new tool to fine-tune their membranes’ pore size for gas separation applications. The red-shift coupled with the fast ISC and charge-transfer processes rationalize the reported photocatalytic activity of BDO-based macromolecules. Co-polymer’s size and composition control are recommended to improve their efficiency in photocatalysis applications

Implementing a Website to Achieve the Communicative Goals of the Business Administration College: A Qualitative Study Applied to the College of Business Administration at Taibah University, Saudi Arabia

In the world today, in which the Internet and websites have become an essential part of the management of the work of institutions and universities because it provides fast communication and business achievement, which has become a measure of the efficiency of any institution in today's world, therefore, there is a growing need for a website that is compatible with this development and represents the institutions to keep up with the increasing pace of communication.In this study, an applied qualitative approach was adopted to highlight the significance of the College of business administration website and its role in achieving  the communicative goals of the college.  Here, an evaluation tool was proposed by the researcher to assess the communication requirements in the college of business administration website, these requirements were categorized in rank order of importance and assigned a numerical point weighting.The main findings, we get as a result of this research are puts forward an evaluation tool to assess the current college website, that would assist the institutions for better understanding the requirements of a compatible website for their communication strategies and goals, this will open the door to improve an electronic system for evaluating websites, Which may be varied according to the objectives and mission of the institution. Keywords: College of business administration website, communicative goals, Communication strategies

Visualizing Spacetime Curvature via Gradient Flows II: An Example of the Construction of a Newtonian analogue

This is the first in a series of papers in which the gradient flows of fundamental curvature invariants are used to formulate a visualization of curvature. We start with the construction of strict Newtonian analogues (not limits) of solutions to Einstein's equations based on the topology of the associated gradient flows. We do not start with any easy case. Rather, we start with the Curzon - Chazy solution, which, as history shows, is one of the most difficult exact solutions to Einstein's equations to interpret physically. We show that the entire field of the Curzon - Chazy solution, up to a region very "close" to the the intrinsic singularity, strictly represents that of a Newtonian ring, as has long been suspected. In this regard, we consider our approach very successful. As regrades the local structure of the singularity of the Curzon - Chazy solution within a fully general relativistic analysis, however, whereas we make some advances, the full structure of this singularity remains incompletely resolved.Comment: 12 pages twocolumn revtex 4-1 9 figures. Expanded and correcte

A New Framework to estimate Pedestrians\u27 Transit Demand from Discrete Mode Choice Modelling applied toward the Prioritization of Pedestrian Infrastructure Investments in Knoxville, TN

The potential social, economic and environmental benefits associated with transit oriented developments encourage investments to enhance transit service, pedestrian infrastructure and parking opportunities. Boosting transit ridership, reducing traffic and congestion, supporting mixed land uses and improving public mobility are among a long list of benefits of a well-developed transit system. Understanding the travel behaviors within the studied areas is the key to finding the best methods to be utilized to attain these benefits. Many studies have focused on locating transit service areas to forecast ridership and apply the appropriate modifications to the existing or planned systems using travel behaviors of transit riders from transit on-boards surveys. Buffer distances were then used to confine service areas of potential transit demand. The bias associated with using transit users’ demographics and the exclusion of demand beyond buffer distances motivated the search for a new method to estimate the demand for transit. Utilizing a mode choice model in estimating transit demand excludes some of the limitations found in other methods. This model was used to estimate potential walk to transit trips from each residential household for home-based work trips for Knox County using estimated probabilities of walking to transit and work trip production rates. The total walk-to -transit trips were associated with the street segments utilized to reach a transit stop. These weights of total trips were then used to prioritize pedestrian infrastructure investments at higher transit demand segments. This method can also be utilized in the prioritization of other service enhancements and stop locations

Evaluation of the Electronic Services System for Taibah University in Light of the Dimensions of Information Systems

The study aims to identify the strengths and weaknesses of the electronic services system at Taibah University by highlighting the achievements of aspects of the information systems from faculty members’ perspectives. First, we defined the three dimensions of information systems using a descriptive approach; then, with the help of four experts, we designed a questionnaire and distributed it to 150 faculty members from different Taibah University departments. We applied statistical analyses, including exploratory factor analysis and frequency analysis, we also applied confirmatory factor analysis and structural equation modeling. The study concludes with a proposed scenario for improving the performance of the electronic services system at Taibah University. Keywords: electronic services system (ES), information systems dimensions, confirmatory factor analysis (CFA).

An Epidemiological, Diagnostic, and Therapeutic Study of the Leishmania tropica Parasite in Iraq’s Anbar Province

This paper involved the registration of 1,936 cases of infection of the Leishmania tropica parasite observed at hospitals and health centers in Ramadi, Fallujah, Baghdadi, and Hit during 2017. The results revealed that the highest rates of infection were found in Ramadi and Fallujah. The 1-10 years age group recorded the highest rate at 35.5%. There was no significant difference (p ≥ 0.05) between the sexes. December and January saw the highest rate of infection, where the rate in rural townships was found to be 65.5%, higher than in urban regions which saw a rate of 34.4%. Facial lesions were the most prominent area of infection, recorded at a rate of 41.3%. The study also included an examination of 180 rodents (94 mice and 86 black rats) - the investigation demonstrated the presence of the amastigote stage at a rate of 43.6% among mice and 53.4% among rats. The study also involved an analysis of the impact of the use of a water extract from the Rhanterium epapposum plant, also locally known as the Arfaj plant, on Leishmania tropica parasite growth. As part of this study, a concentration of between 0.05-5 mg/ml was used. The application of these concentrations led to an inhibitory effect on parasite growth - an application of relatively higher concentrations caused greater effects in times of growth between 1-5 days