The Hubble Web: The Dark Matter Problem and Cosmic Strings

I propose a reinterpretation of cosmic dark matter in which a rigid network of cosmic strings formed at the end of inflation. The cosmic strings fulfill three functions: At recombination they provide an accretion mechanism for virializing baryonic and warm dark matter into disks. These cosmic strings survive as configurations which thread spiral and elliptical galaxies leading to the observed flatness of rotation curves and the Tully-Fisher relation. We find a relationship between the rotational velocity of the galaxy and the string tension and discuss the testability of this model.Comment: 5 page

NIGERIA’S ENERGY CHALLENGE AND POWER DEVELOPMENT: THE WAY FORWARD

The ever increasing demand and meager supply of energy in Nigeria has been a great challenge to her development. This situation is becoming critical, with increasing population not balanced by an adequate energy development programme. The incessant power generation failure has grossly affected the economy, seriously slowing down development in rural and sub-rural settlements, with present energy policy mainly benefiting urban dwellers. Globally, energy projections stipulate that between 2002 and 2025, global energy needs may rise by over 34%, with that of developing nations doubling this percentage. A robust solution must be found to end the nation’s energy crises. This Viewpoint compares the energy potential of Nigeria with the challenges faced. Nigeria receives a huge amount of solar radiation, has abundant wind energy resources, and large deposits of fossil fuel, as well as enormous hydro-power resources from Niger and Benue Rivers. However, of these about 80% of hydro-power remains untapped, the total 5.5KW-hr/m2/day of solar radiation is not utilized and wind energy resources remain unexploited. The solution lies in creating a mixed supply of energy in which as yet untapped renewable resources are combined with abundant nonrenewable fossil fuel, including the massive quantities of gas wasted from crude oil exploitation

Ergonomic Consideration of the Effect of Flour Dust on Peak Expiratory Flow Rate of Bakers in Abeokuta, Ogun State

Flour dusts are one of the most harmful chemicals in the bakery industries which could lead to serious heart and lung diseases. This study investigated the effect of flour dust on Peak Expiratory Flow Rate of male bakers in Abeokuta, Ogun State, Nigeria with the relationship to the anthropometrical parameters. A total of One hundred Eighty (180) male participants were investigated, where ninety (90) participants were bakers and ninety (90) individuals as control group. The Peak expiratory flow rate (PEFR) and anthropometrical parameters of the participant were measured using mini-Wright peak flow meter (PFM 20, OMRON) and Detecto PD300MDHR (Cardinal Scale manufacturing company, USA) column scale with digital height rod was used to measure body mass [kg] and height (cm) respectively. The PEFR and anthropometrical parameters of the bakers and control groups were analysed using descriptive statistics and T-test with SPSS. The results showed that lower PEFR, 182.67 ± 16.34 L/min existed in bakers compared to 287.67 ± 17.02 L/min in the control study. The result also showed that a significant correlation exist between body mass, height and age (P < 0.01), PEFR, height (P < 0.05) and years of exposure (P < 0.01) of the bakers respectively. Furthermore, the results also showed that workers in the dusting and mixing of flour are at a risk of developing related pulmonary function impairment such as asthma. The study concluded that there is need to develop an effective intervention strategy, treatment seeking behaviour through awareness programs to prevent lung impairment diseases among the bakery workers

Astrophysics in Southern Africa

The government of South Africa has identified astronomy as a field in which their country has a strategic advantage and is consequently investing very significantly in astronomical infrastructure. South Africa now operates a 10-m class optical telescope, the Southern African Large Telescope (SALT), and is one of two countries short listed to host the Square Kilometre Array (SKA), an ambitious international project to construct a radio telescope with a sensitivity one hundred times that of any existing telescope. The challenge now is to produce an indigenous community of users for these facilities, particularly from among the black population which was severely disadvantaged under the apartheid regime. In this paper I briefly describe the observing facilities in Southern Africa before going on to discuss the various collaborations that are allowing us to use astronomy as a tool for development, and at the same time to train a new generation of astronomers who will be well grounded in the science and linked to their colleagues internationally.Comment: Paper given at the 2007 meeting of the National Society of Black Physicists; 10 pages, 2 photographs. To appear in American Institute of Physics Conference Proceeding

Observations of an Energetically Isolated Quiet Sun Transient: Evidence of Quasi-Steady Coronal Heating

Increasing evidence for coronal heating contributions from cooler solar atmospheric layers, notably quiet Sun (QS) conditions, challenges standard solar atmospheric descriptions of bright transition region (TR) emission. As such, questions to the role of dynamic QS transients in contributing to the total coronal energy budget are elevated. Using observations from the {\it Atmospheric Imaging Assembly} and {\it Heliosemic Magnetic Imager} on board the {\it Solar Dynamics Observatory}, and numerical model extrapolations of coronal magnetic fields, we investigate a dynamic QS transient energetically isolated to the TR and extruding from a common footpoint shared with two heated loop arcades. A non-casual relationship is established between episodic heating of the QS transient and wide-spread magnetic field re-organization events, while evidence is found favoring a magnetic topology typical of eruptive processes. Quasi-steady interchange reconnection events are implicated as a source of the transient's visibly bright radiative signature. We consider the QS transient's temporally stable ($\approx$\,35\,min) radiative nature occurs as a result of the large-scale magnetic field geometries of the QS and/or relatively quiet nature of the magnetic photosphere, which possibly act to inhibit energetic buildup processes required to initiate a catastrophic eruption phase. This work provides insight to the QS's thermodynamic and magnetic relation to eruptive processes quasi-steadily heating a small-scale dynamic and TR transient. This work elevates arguments of non-negligible coronal heating contributions from cool atmospheric layers in QS conditions, and increases evidence for solar wind mass feeding of dynamic transients therein.Comment: 13 pages, 9 figure