964 research outputs found
Predicting Smoking Behaviors Among Junior High School Students in Ghana
Despite the rising rate of smoking in sub-Sahara African countries, measures to control the tobacco epidemic have been limited to developed countries. The purpose of the present study was to recommend predictive models for determining predictors of smoking tendencies among junior high school students in Ghana. The 2009 Global Youth Tobacco Survey (GYTS) served as the data source. The GYTS is a school-based survey designed to enhance the ability of countries to monitor tobacco use among youth and to guide the implementation and evaluation of tobacco control and prevention programs. Logit model and forward selection were used to choose predictive variables for smoking tendencies and behaviors. Receiver Operating Characteristic (ROC) curve, Area under the curve (AUC) and C-Index were validation tools used to assess the predictive power of recommended models. Results showed promising potential for different predictive models: where students smoked, having friends who smoked, having people smoke in their presence, chewing tobacco products, and a student's sex significantly predicted their smoking tendencies
Estimating Health Care Costs Among Fragile and Conflict Affected States: an Elastic Net-Risk Measures Approach
Fragile and conflict affected states (FCAS) are those in which the government lacks the political will and/or capacity to provide the basic functions necessary for poverty reduction, economic development, and the security of human rights of their populations.Until recent history, unfortunately, the majority of research conducted and universal health care debates have been centered around middle income and emerging economies. As a result, FCAS have been neglected from many global discussions and decisions. Due to this neglect, many FCAS do not have proper vaccinations and antibiotics. Seemingly, well estimated health care costs are a necessary stepping stone in improving the health of citizens among FCAS. Fortunately, developments in statistical learning theory combined with data obtained by the WBG and Transparency International make it possible to accurately model health care cost among FCAS. The data used in this paper consisted of 35 countries and 89 variables. Of these 89 variables, health care expenditure (HCE) was the only response variable. With 88 predictor variables, there was expected to be multicollinearity, which occurs when multiple variables share relatively large absolute correlation. Since multicollinearity is expected and the number of variables is far greater than the number of observations, this paper adopts Zou and Hastie\u27s method of regularization via elastic net (ENET). In order to accurately estimate the maximum and expected maximum HCE among FCAS, well-known risk measures, such as Value at Risk and Conditional Value at Risk, and related quantities were obtained via Monte Carlo simulations. This paper obtained risk measures at 95 security level
Maternal Mortality in Ghana: Impact of the Fee-Free Delivery Policy and the National Health Insurance Scheme
Maternal mortality (MMR) is the second largest cause of female deaths in Ghana. Yet, many households cannot afford the cost of skilled delivery The study utilized the Panel Data Model to examine the impact of the fee-free delivery (FDP) and the National Health Insurance Policy (NIP) exemptions on MMR in Ghana. The Demographic and Health Survey reports on Ghana from 2002 to 2009 served as the main data source. Data were analyzed using Panel data model with within group fixed effects estimator. MMR declined significantly over the period studied. Both FDP and NIP positively impacted MMR at a 5% level of significance. In addition, skilled delivery was a significant predictor of MMR. Stakeholders would do well to ensure NIP is adequately funded in order to sustain the decline in MMR
Prevalence of Active School Transportation in the Upper East and Upper West Regions of Ghana
The use of active transportation such as walking to and from school is on the decline globally. The primary purpose of the study was to determine the prevalence of active school transportation among primary and junior high school students in the Upper East and Upper West regions of Ghana. The secondary purpose was to examine predictors for meeting the recommended daily number of steps. A total of 2505 (1117 boys and 1388 girls) primary (1583) and junior high school (922) students participated in the study. The distances from children\u27s homes to their schools, heights, and body weights were measured âtheir heights were used to estimate their stride lengths. The step count for each participant to and from school each day was calculated. Data were analyzed using conditional percentage distribution and Logit model. Analyses indicated that 98.96% of participants used active transportation to and from school. Over 63% of the students were within the normal BMI range. However, 26.47% of the participants were either thin or underweight while 9.9% were either overweight or obese. Overall, 46.47% of the participants met the recommended daily steps. The Logit model indicated that educational level, BMI, mode of transportation, region, height, and age were significant predictors for meeting the recommended daily number of steps. The prevalence of school active transportation in the present study was high compared to that reported in other studies. Furthermore, the prevalence of thinness and underweight were higher than in previous studies, while the prevalence in overweight and obesity were lower
Host-parasite interactions between Lernaeocera branchialis (Copepoda: Pennellidae) and its host Gadus morhua (Teleosti: Gadidae)
Lernaeocera branchialis (Linnaeus, 1767) is a parasitic copepod possessing a complex dual-host lifecycle. The âdefinitiveâ gadoid hosts, including Gadus morhua (Atlantic cod), Melanogrammus aeglefinus (haddock) and Merlangius merlangus (whiting), are infected by the fertilised female, which penetrates the hostâs ventral aorta or bulbus arteriosus whilst undertaking extensive metamorphosis and a haematophagous lifestyle. The pathogenic effects of this activity upon the host have been well documented and mortality may occur, especially when multiple parasites are present. These negative impacts on cod, particularly juveniles, by L. branchialis have the potential to adversely affect cod aquaculture in the future, and already vulnerable wild cod stocks. This PhD project therefore, investigated the immune response of wild haddock and cultured-cod post-infection by L. branchialis, and the possible mechanisms by which the parasite modulates/evades the hostâs immune response. The systemic immune response of both wild haddock and cultured-cod post-infection by L. branchialis depended on the maturation stage of the parasite, and in the former host species, upon the infection intensity. Wild haddock harbouring fully metamorphosed females showed an increase in circulating thrombocytes and a decrease in serum protein levels however; if multiple mature L. branchialis were present the haddock possessed reduced circulating monocytes, and increased circulating thrombocytes and serum anti-trypsin activity. Infection by L. branchialis was also associated with a suppressive effect on haddock serum spontaneous haemolytic activity. These responses were thought to be due to the host trying to counteract the increased damage caused by the massive increase in size and the feeding of the mature parasite, which is more pronounced when multiple parasites are present, resulting in the increase in some parameters and the âconsumptionâ of others. However, the effect of parasite-derived secretions and other pathogens due to observations on wild fish could not be discounted. The laboratory-infection of cultured-cod from two different sources was also performed in order to study the immune response over time. The two groups of cod showed differences in their immune response to L. branchialis. The first group showed suppressed respiratory burst activity of phagocytes, as the parasite reached the early penella sub-stage, whilst no suppression in phagocyte respiratory burst activity was found in the second group. The parasite was found to migrate along the afferent branchial artery of the cod where a thrombus formed and was present throughout its migration into the ventral aorta. At 14 d post-infection, leukocytes expressing Interleukin 8 mRNA were observed within the free-flowing blood at the periphery of the organising thrombus within the lumen of the ventral aorta. This was speculated to aid the recruitment and activation of leukocytes to the site, and the maturation and neovascularisation of granulation tissue. The infection of the second group subsided with the death of the parasite, and none of the parasites metamorphosed past the early penella sub-stage. The live parasites infecting the first group of cod did not possess IgM or complement component C3 binding on their cuticle, however, both IgM and C3 binding occurred on the dead parasites in the second infection trial. This may highlight the importance of these opsonins and the cytotoxic effect of phagocytes in the elimination of L. branchialis by some cod. However, the first infection was terminated as the parasite reached the early penella sub-stage due to a loss of stock cod prior to the study, so the long-term success of the infection can not be concluded. Therefore, the immune response to infection needs to be determined over the entire metamorphosis of L. branchialis to determine whether the infection was successful or not, and preferably in populations with varying susceptibility to L. branchialis. This will not be possible without further studies into the resistance of different stocks of cultured-cod. Many arthropod parasites, such as ticks and salmon lice, have been previously documented to produce pharmacologically active secretions, aiding host invasion and parasite feeding, preventing the host immune response from working effectively against the parasite, all aimed at improving survival of the parasite. Therefore, the effects of the secretory/excretory products (SEPs) produced during the initial infective stage and by the mature, fully metamorphosed female on the immune response of cultured-cod in vitro, and the location of exocrine glands associated with the oral region of the parasite were investigated. The SEPs from the infective stage of the parasite were found not to affect the intracellular hydrogen peroxide (H2O2) production of phagocytes. The practical difficulties in collecting large quantities of the SEPs from the infective stage meant that their effects could not be tested on the other host immune parameters studied. The SEPs from fully metamorphosed female L. branchialis, however, had a number of suppressive effects on the host immune response in vitro including: 1) suppression of the intracellular production of cytotoxic H2O2 during the respiratory burst of phagocytic leukocytes post-PMA stimulation, 2) suppression of the production of macrophage activating factor by leukocytes with a priming effect on naĂŻve phagocyte function, and 3) suppression of the chemo-attraction âpowerâ of zymosan activated cod serum, i.e. anaphylatoxin activity, on head kidney-derived leukocytes. These effects were dose-dependent, and highlight the capacity of L. branchialis to suppress its hostâs innate immune response at the local feeding area. Further work is required to establish the mechanisms by which the parasite-derived SEPs suppress these host immune parameters, and to identify which molecules produced by the parasite are responsible. The correlation between these in vitro results, and systemic immune parameters measured from laboratory-infected Atlantic cod and wild infected haddock are discussed. Host immuno-modulation by other arthropod parasites is mediated by pharmacologically active secretions produced by exocrine glands. Therefore, the exocrine glands of the infective and fully metamorphosed female L. branchialis were also investigated in order to identify those that might be responsible for the secretion of host-modifying products. Adult female exocrine glands were mapped using diaminobenzidine (DAB), most commonly known to stain peroxidases and catalases. These compounds are known to be involved in the neutralisation of harmful free radicals which are released during the respiratory burst and tissue damage. Such products may therefore be important protective secretory components at the site of feeding / infection. Exocrine glands were located in the infective stage associated with the oral region, one pair termed the anterior gland complex (AGC), and the other pair extending either side of the oral cone termed the circum-oral glands (CG). These were further investigated using light microscopy and transmission electron microcopy. The AGC and CGs possessed multi-component secretions and they possessed secretory vesicles, abundant and highly active rough endoplasmic reticulum and Golgi apparatus suggesting that protein is an important component of the secretory products. These glands were also observed in the fully metamorphosed females where they had increased in size within the cephalothorax post-metamorphosis. It is hoped that the identification of these glandular structures, which are thought to secrete within the local vicinity of the oral cone, will aid future studies regarding the identification and secretion kinetics of parasite-derived molecules during the infection and feeding process.EThOS - Electronic Theses Online ServiceFisheries Society of the British IslesGBUnited Kingdo
Neutralino Dark Matter beyond CMSSM Universality
We study the effect of departures from SUSY GUT universality on the
neutralino relic density and both its direct detection and indirect detection,
especially by neutrino telescopes. We find that the most interesting models are
those with a value of lower than the universal case.Comment: 20 pages, 12 figures, JHEP format. Figures improved for B&W,
references added, typos and english correcte
A companion to a quasar at redshift 4.7
There is a growing consensus that the emergence of quasars at high redshifts
is related to the onset of galaxy formation, suggesting that the detection of
concentrations of gas accompanying such quasars should provide clues about the
early history of galaxies. Quasar companions have been recently identified at
redshifts up to . Here we report observations of Lyman-
emission (a tracer of ionised hydrogen) from the companion to a quasar at
=4.702, corresponding to a time when the Universe was less than ten per cent
of its present age. We argue that most of the emission arises in a gaseous
nebula that has been photoionised by the quasar, but an additional component of
continuum light -perhaps quasar light scattered from dust in the companion
body, or emission from young stars within the nebula- appears necessary to
explain the observations. These observations may be indicative of the first
stages in the assembly of galaxy-sized structures.Comment: 8 pages, 4 figures, plain LaTeX. Accepted for publication in Natur
Addressing conflicts of interest in Public Private Partnerships
<p>Abstract</p> <p>Background</p> <p>Many articles have been written on conflicts of interests (COIs) in fields such as medicine, business, politics, public service and education. With the growing abundance of Public Private Partnerships (PPPs), often involving complex relationships among the partners, it is important to understand how COIs can be mitigated and managed in PPPs.</p> <p>Discussion</p> <p>We wanted to study PPPs, particularly in the areas of global health and agriculture, but discovered no single source of information available to identify and compare various approaches for avoiding and managing COIs in PPPs. This is a significant gap, especially for those wishing to study, compare and strengthen existing COI policies related to PPPs. In order to bridge this gap, we reviewed how PPPs currently address COIs and highlight what might be considered good practice in developing COI policies. We reviewed the online COI policies of 10 PPPs in global health and agriculture, and interviewed two global health PPP chief executives.</p> <p>Summary</p> <p>Based on our review of policies and interviews, we conclude that there exists a range of good practices including attention to accountability and governance, acknowledgement and disclosure, abstention and withdrawal, reporting and transparency, and independent monitoring. There appears to be a need for PPPs to interact closely and learn from each other on these parameters and to also place more emphasis on independent external monitoring of COIs as a means of strengthening their major social objectives on which their activities are largely predicated. We also recommend the establishment of a web based database, which would serve as a forum to discuss COI issues and how they can be resolved.</p
Contraband Cigarette Purchasing from First Nation reserves in Ontario and Quebec: Findings from the 2002â2014 ITC Canada Survey
Backround: The availability of contraband cigarettes provides incentives for price-sensitive smokers to reduce their monetary costs of smoking. The objectives of this study were to examine whether Canadian smokersâ geographic proximity to First Nations reserves and attempts to quit smoking influenced the likelihood of purchasing lower-cost cigarettes from reserves. Methods: Data were from the International Tobacco Control (ITC) Canada Survey, a prospective survey of Canadian adult smokers conducted from 2002 to 2014 using telephone and online interviewing methods. Analysis was restricted to smokers from Ontario (n=2105) and Quebec (n=1427) participating in at least one survey wave. Smokersâ postal codes were used to calculate distance to the nearest reserve. Weighted logistic generalised estimating equations (GEE) regression examined the linear relationship between distance and the log odds of last purchasing cigarettes on reserve in each province. GEE models also examined the relationship between past-year quit attempts and the log odds of on-reserve purchasing. Results: Controlling for other factors, from 2002â2014, smokers from Ontario who lived 10 km closer to reserves than otherwise similar smokers had significantly higher odds of last purchasing on reserve (OR ranged from 1.16 to 1.65). Distance had little effect on smokersâ purchasing behaviours in Quebec. Moreover, in Ontario, for every 10 km increase in distance, smokers who did not try to quit had significantly greater odds of purchasing from a reserve than smokers who tried to quit (p=0.002). Conclusion: In order for tobacco taxation policies to achieve their maximal benefit, governments must limit potential sources of lower-cost cigarettes. Collaborative governance arrangements can ensure tobacco products sold on reserve to non-Indigenous people are appropriately taxed while allowing First Nations communities to keep the revenue generated by such taxes.US National Cancer Institute || Canadian Institutes of Health Research || Canadian Tobacco Control Research Initiativ
- âŠ