1,140 research outputs found
Cosmology on Compact and Stable Supergravity Background
We propose a cosmological model of D3-brane universe on compact and stable
supergravity background of wrapped D7-branes in type IIB string theory
previously argued to be dual to pure N=1 SU(N) gauge theory in four dimensions.
A model universe of order Planck size near the UV boundary dynamically flows
toward the IR with constant total energy density and accelerating expansion
followed by smooth transition to decelerating expansion and collides with the
wrapped D7-branes at the IR boundary. The model addresses the horizon and
flatness problems with most of the expansion produced during the decelerating
expansion phase. The inflationary scenario is used to generate sources of
inhomogeneities in the cosmic microwave background radiation and seeds for
large scale structure formation from quantum fluctuations which exit the Hubble
radius early during the accelerating expansion phase and the model addresses
the inhomogeneity problem with red tilt in the power spectrum. We propose that
the kinetic energy of the model universe is converted to matter and radiation
by the collision followed by formation of baryons that stabilizes the model
universe against gravitational force from the background at a finite distance
from the IR boundary with the wrapped D7-branes serving as sources of color.
Friedmann evolution then takes over with a positive cosmological constant term
coming from the remaining potential energy density which is interpreted as dark
energy. The magnitude of dark energy density is smaller than the total energy
density during the flow by a ratio of the scale factor when the model universe
appears in the UV to the scale factor at the moment of collision and stays
constant while the matter-radiation density falls during Friedmann expansion.Comment: 30 page
One Instrument, Many Targets: Timor-Leste?s Macroeconomic Policy Challenge
It is difficult to be sanguine about Timor-Leste?s progress towards achieving the localized Millennium Development Goals (MDGs). The share of people living under the national poverty line increased from 36 per cent in 2001 to 50 per cent in 2007. The maternal mortality ratio remains unacceptably high. About half of the children are underweight. In Dili, the capital, 58 per cent of the youth have no jobs (Government of Timor Leste and UN, 2009). Can Timor-Leste scale-up MDG-related investments? (?)One Instrument, Many Targets: Timor-Leste?s Macroeconomic Policy Challenge
Regulating khat - Dilemmas and opportunities for the international drug control system
Background: The regulation of khat, one of the most recent psychoactive drugs to become a globally traded commodity, remains hotly contested within different producer and consumer countries. As regimes vary, it has been possible to compare khat policies in Africa, Europe and North America from different disciplinary perspectives.
Methods: Field research was conducted in East Africa and Europe, using a combination of semistructured interviews, participant observation and the analysis of trade statistics.
Results: The research established the significance of khat for rural producers, regional economies, as a tax base and source of foreign exchange. At the same time, khat as a psychoactive substance is associated with health and public safety problems that in turn are met with often ill-informed legislative responses. Bans have in turn lead to the criminalisation of users and sellers and illegal drug markets.
Conclusion: The empirical work from Africa provides a strong argument for promoting evidence-based approaches to khat regulation, harnessing the positive aspects of the khat economy to develop a control model that incorporates the voices and respects the needs of rural producers. Ultimately, the framework for khat may provide both a model and an opportunity for revising the international treaties governing the control of other plant psychoactive-based substances
Participatory identification of indicators for assessing options for climate compatible development of smallholder farmers in the Central Rift Valley of Ethiopia.
Provider initiated HIV testing and counseling, acceptance and disclosure of HIV status and factors related to them among outpatients in Debre Berhan Referral Hospital
Background: HIV counseling and testing is the critical entry-point for engagement into treatment and care as well as for primary and secondary HIV prevention efforts. Despite the importance of this step, most HIV infected patients globally, and particularly in resource-poor settings, are unaware of their HIV status and the uptake of voluntary counseling and testing (VCT) services is relatively limited.Objectives: To assess the magnitude of Provider Initiated Testing and Counseling (PITC) acceptance and disclosure and factors related to them among outpatient department patients.Methods: A facility-based cross-sectional quantitative survey was taken from December 1, 2010 to January 10, 2011 among 414 clients coming to the outpatient department in Debre Berhan Referral Hospital. Data were collected, entered into EPI info version 3.5.1 and analyzed using SPSS version 16. A logistic regression model was used to assess factors associated with PITC acceptance and disclosure of test results.Results: A total of 414 study participants (with a response rate of 100 %) responded to the questionnaire. Acceptance of PITC among OPD patients was 83.6%. Adjusted correlates of PITC acceptance included female gender (AOR=2.27, 95% CI=1.16-4.42) and knowledge about HIV transmission (AOR=4.08, 95% CI=1.98-9.91). Key barriers to accepting PITC included being apparently healthy (25%), being tested before (22.1%) and fear of stigma and discrimination (19.1%). Of the 346 respondents who accepted PITC, 288 (83.2%) had a plan to disclose their results to any other person. Compared with the age group 45 and above, those 15-24 years old were less likely to disclose their HIV status (AOR=0.16, 95% CI=0.04-0.62). Disclosure of test result was associated with occupation(AOR=5.42, 95% CI=1.44-20.43) and negative test result (AOR=4.00, 95% CI=1.53-10.47).Conclusion and recommendations: In this study, PITC acceptance was promising and should be expanded to other health facilities. Efforts should be strengthened to decrease factors which impede HIV test result disclosure.
Steering far-field spin-dependent splitting of light by inhomogeneous anisotropic media
An inhomogeneous anisotropic medium with specific structure geometry can
apply the tunable spin-dependent geometrical phase to the light passing through
the medium, and thus can be used to steer the spin-dependent splitting (SDS) of
light. In this paper, we exemplify this inference by the q plate, an
inhomogeneous anisotropic medium. It is demonstrated that when a linearly
polarized light beam normally passes through a q plate, k-space SDS first
occurs, and then the real-space SDS in the far-field focal plane of a
converging lens is distinguishable. Interestingly, the SDS, described by the
normalized Stokes parameter S3 shows a multilobe and rotatable splitting
pattern with rotational symmetry. Further, by tailoring the structure geometry
of the q plate and/or the incident polarization angle of light, the lobe number
and the rotation angle both are tunable. Our result suggests that the q plate
can serve as a potential device for manipulating the photon spin states and
enable applications such as in nano-optics and quantum information.Comment: 5 pages, 5 figure
Know-how of primary eye care among Health Extension Workers (HEWs) in Southern Ethiopia
Background/ Aim: Frontline health personnel can play key role in preventing and controlling blindness if they have good understanding of primary eye care (PEC). This study determined knowledge, attitude and practice of PEC among health extension workers (HEWs) in southern Ethiopia. Methods: A cross sectional community based study was conducted between June and July 2007 in five randomly selected woredas of Gurage Zone. Quantitative data were collected using a questionnaire completed in a face-faceinterview with 111 HEWs. And this was supported with qualitative information from two focus group discussions. Result: HEWs (87%) had poor understanding of the functional definition of blindness. They identified cataract (85%), trachoma (96%) and trauma (64%) as causes of blindness. Although most (89%) correctly mentioned signs and symptoms of trachoma, but only 10% could describe its control strategy. Refractive error was wrongly perceived by most (77%) as only a near vision problem. Glaucoma was barely known but causes of childhood blindness were well identified.. Their main source of information for eye health care was pre-service training (50%) and refresher trainings by international organizations (46%). HEWs practiced mainly preventive aspects of PEC. Group discussions revealed that HEWs have good will to participate in PEC but barriers such as inadequate knowledge and lack of basic suppliesare limiting their contribution. Conclusion: Know-how of blinding eye disease among HEWs is too low to enable them contribute meaningfullytowards prevention of blindness. It is recommended that PEC be incorporated in their training curriculum
Un seul Instrument Pour Plusieurs Cibles : Le Défi Posé par la Politique Macroéconomique du Timor-Leste
Un seul Instrument Pour Plusieurs Cibles : Le Défi Posé par la Politique Macroéconomique du Timor-Leste
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