Proper Size of the Visible Universe in FRW Metrics with Constant Spacetime Curvature

In this paper, we continue to examine the fundamental basis for the Friedmann-Robertson-Walker (FRW) metric and its application to cosmology, specifically addressing the question: What is the proper size of the visible universe? There are several ways of answering the question of size, though often with an incomplete understanding of how far light has actually traveled in reaching us today from the most remote sources. The difficulty usually arises from an inconsistent use of the coordinates, or an over-interpretation of the physical meaning of quantities such as the so-called proper distance R(t)=a(t)r, written in terms of the (unchanging) co-moving radius r and the universal expansion factor a(t). In this paper, we use the five non-trivial FRW metrics with constant spacetime curvature (i.e., the static FRW metrics, but excluding Minkowski) to prove that in static FRW spacetimes in which expansion began from an initial signularity, the visible universe today has a proper size equal to R_h(t_0/2), i.e., the gravitational horizon at half its current age. The exceptions are de Sitter and Lanczos, whose contents had pre-existing positions away from the origin. In so doing, we confirm earlier results showing the same phenomenon in a broad range of cosmologies, including LCDM, based on the numerical integration of null geodesic equations through an FRW metric.Comment: Accepted for publication in Classical and Quantum Gravit

A Test of Cosmological Models using high-z Measurements of H(z)

The recently constructed Hubble diagram using a combined sample of SNLS and SDSS-II Type Ia SNe, and an application of the Alcock-Paczynski (AP) test using model-independent Baryon Acoustic Oscillation data, have suggested that the principal constraint underlying the cosmic expansion is the total equation-of-state of the cosmic fluid, rather than that of its dark energy. These studies have focused on the critical redshift range (0 < z < 2) within which the transition from decelerated to accelerated expansion is thought to have occurred, and they suggest that the cosmic fluid has zero active mass, consistent with a constant expansion rate. The evident impact of this conclusion on cosmological theory calls for an independent confirmation. In this paper, we carry out this crucial one-on-one comparison between the R_h=ct Universe (an FRW cosmology with zero active mass) and wCDM/LCDM, using the latest high-z measurements of H(z). Whereas the Type Ia SNe yield the integrated luminosity distance, while the AP diagnostic tests the geometry of the Universe, the Hubble parameter directly samples the expansion rate itself. We find that the model-independent cosmic chronometer data prefer R_h}=ct over wCDM/LCDM with a BIC likelihood of ~95% versus only ~5%, in strong support of the earlier SNeIa and AP results. This contrasts with a recent analysis of H(z) data based solely on BAO measurements which, however, strongly depend on the assumed cosmology. We discuss why the latter approach is inappropriate for model comparisons, and emphasize again the need for truly model-independent observations to be used in cosmological tests.Comment: 22 pages, 1 figure, 1 table. Accepted for publication in the Astronomical Journa

The Galactic Center: An Interacting System of Unusual Sources

The region bounded by the inner tens of light years at the center of the Milky Way contains five principal components that coexist within the central deep gravitational potential well. These constituents are a black hole candidate (Sgr~A*) with a mass equivalent to $2.6\pm0.2\times 10^6$ suns, a surrounding cluster of evolved stars, a complex of young stars, molecular and ionized gas clouds, and a powerful supernova-like remnant. The interaction of these components is responsible for many of the phenomena occurring in this complex and unique portion of the Galaxy. Developing a consistent picture of the primary interactions between the components at the Galactic Center will improve our understanding of the nature of galactic nuclei in general, and will provide with a better defined set of characteristics of black holes. For example, the accretion of stellar winds by Sgr A* appears to produce far less radiation than indicated by estimates based on models of galactic nuclei.Comment: 26 pages (text only); see the published article with ten figures under Science Online Article http://www.physics.nwu.edu/research/zadeh.htm

Neutrinos from the Galactic Center in the Light of its Gamma-Ray Detection at TeV Energy

We re-evaluate the event rate expected in km^3-scale detectors for neutrinos from the direction of the Galactic Center (GC) in light of recent spectral measurements obtained by the HESS instrument for ~TeV gamma-radiation from this direction. In the most plausible scenario the re-evaluated event rate is smaller than that previously calculated--and here re-calculated--on the basis of EGRET data. However, the GC TeV gamma-ray detections by the Whipple, CANGAROO, and HESS instruments, together with the strong indications for an overabundance of cosmic rays coming from the GC at EeV energies, strengthen the expectation for a detectable, TeV-PeV GC neutrino signal from proton-proton interactions in that region. If the TeV gamma-ray--EeV cosmic ray anisotropy connection is correct, this signal will be detectable within a year and half for km^3-scale neutrino detectors in the Northern Hemisphere at super-TeV energies and, significantly, should also be detectable in 1.6 years by the South Polar IceCube detector at energies > 10^14 eV. The GC neutrino signal should also produce a detectable signal from neutrino showering and resonant W^- production by anti-electron-neutrinos in the volume of a km^3-scale detector.Comment: 12 pages, 1 figure. Version accepted to ApJ Letters. Minor amendment

The Sustainable Corporation

The industrial sector is highlighted as the chief cause of the rapidly environmental change in the recent years. Because natural environment has strong correlation with human life and his activities to achieve well being, thereby industrial or business sector, the chief of human activities, is demanded to play as the central role in Sustainable Development. According to sustainable concept, there are three missions that have to be performed in sustainable development-sustainability in economics, environment and social. Of the three missions, environment and social are always taken in weak positions by business Actors. As the central actors in sustainable development, business actors should take the three of missions balance and together in their entire business activities. Based on same literatures and some successful stories in business practices, the author founded two important patterns that evolve recently how a corporation could be named as a suistanle corporation. First, the corporation developed partnership in eco-industrial part and the second; the corporation did its corporate social responsibility

Beyond the Economic: The Freedoms, Capabilities, and Social Capital of Latin American Women Entrepreneurs in San Francisco

In light of the scholarly debate surrounding the goals and mixed effects of development programs, particularly in recent years in relation to microfinance, this study investigates the effects of economic development programs on Latin American women entrepreneurs in San Francisco’s Mission District. It demonstrates that microfinance, when combined with education, can provide important non-economic benefits that contribute to increased freedoms and capabilities for immigrant women entrepreneurs. Drawing on qualitative interviews with ten business owners, as well as a review of the existing literature surrounding development, immigration, and gender, this research argues that owning a business in the US can produce enhanced freedoms and capabilities for Latin American immigrant women, including changing identities and family dynamics and increased social opportunities like education and healthcare. This study also expands the notion of capital beyond the economic by considering how the shared cultural capital of the Latino community can contribute to a strong network of social capital among immigrant women entrepreneurs, which in turn helps to sustain their businesses and ensure their continued economic success. Several potential barriers to success that this group of immigrant women faces are the challenges of renegotiating gender norms upon transition to a new culture and joining the work force, as well as the obstacles and social stigmas associated with immigration status and citizenship rights. This study concludes that these barriers can prevent the enjoyment of other freedoms like political participation and that displacement of immigrants through gentrification also threatens economic success by devaluing established immigrant networks of social capital

Developing ODP student placements

In a similar way to nursing and other health professions, elements of the education of operating department practitioners (ODPs) can only be contextualised by clinical practice involvement (Stockhausen and Strutt, 2005; Higginson, 2006; Morgan, 2006). The importance of high-quality placement experiences for all UK health professions is widely acknowledged (Quality Assurance Agency, 2001). Prior to 2009, students on the Diploma in Higher Education ODP programme undertook four clinical placements in the same Trust or organisation. At the time of the project there was a shortfall in the number of placements available and, although the university explored placing students in different clinical areas, such as private healthcare providers and new areas in the NHS, none could provide the full learning experience for students to achieve the required competencies. The course team developed a system that uses placements in a variety of settings and ensures students can gain the required outcomes. The new approach involves auditing for individual placements, instead of for the full course duration. Students are now informed throughout recruitment and selection events that they should be undertaking placements in a minimum of three different organisations. Students now move to a different organisation with every experience, to gain a variety of clinical knowledge. This has resulted in the greater use of clinical placements and the development of new areas for students to gain experience. The benefits of students’ experiences have increased, as they can develop skills and understanding of the ODP role from different perspectives