35 research outputs found
The Effectiveness of profit warnings in predicting decline in share prices in theNSE: an event study approach.
A Research project submitted in partial fulfillment of the requirements for the degree of Bachelor of Business Science in Actuarial Science at Strathmore UniversityProfit warnings are issued by companies to inform shareholders that the current year’s profit will be significantly lower than the profit of the previous year or the anticipated profit for the current year (Jensen, 2005). The aim of this paper is to determine whether investors can rely on profit warnings as lead indicators of falling share prices. An event study is carried out to determine when the decline of share prices occurs with reference to issuance of profit warnings. A hypothesis test is then carried out to determine if the decline prior to the issuance of a profit warning is of material significance. The data used is of Kenya’s NSE, between the years 2002 and 2016
Low-Cost Sensors and Multitemporal Remote Sensing for Operational Turbidity Monitoring in an East African Wetland Environment
Many wetlands in East Africa are farmed and wetland reservoirs are used for irrigation, livestock, and fishing. Water quality and agriculture have a mutual influence on each other. Turbidity is a principal indicator of water quality and can be used for, otherwise, unmonitored water sources. Low-cost turbidity sensors improve in situ coverage and enable community engagement. The availability of high spatial resolution satellite images from the Sentinel-2 multispectral instrument and of bio-optical models, such as the Case 2 Regional CoastColor (C2RCC) processor, has fostered turbidity modeling. However, these models need local adjustment, and the quality of low-cost sensor measurements is debated. We tested the combination of both technologies to monitor turbidity in small wetland reservoirs in Kenya. We sampled ten reservoirs with low-cost sensors and a turbidimeter during five Sentinel-2 overpasses. Low-cost sensor calibration resulted in an R 2 of 0.71. The models using the C2RCC C2X-COMPLEX (C2XC) neural nets with turbidimeter measurements (R 2 = 0.83) and with low-cost measurements (R 2 = 0.62) performed better than the turbidimeter-based C2X model. The C2XC models showed similar patterns for a one-year time series, particularly around the turbidity limit set by Kenyan authorities. This shows that both the data from the commercial turbidimeter and the low-cost sensor setup, despite sensor uncertainties, could be used to validate the applicability of C2RCC in the study area, select the better-performing neural nets, and adapt the model to the study site. We conclude that combined monitoring with low-cost sensors and remote sensing can support wetland and water management while strengthening community-centered approaches.</p
Longitudinal Study of Selected Bacterial Zoonoses in Small Ruminants in Tana River County, Kenya
Brucellosis, Q fever, and leptospirosis are priority zoonoses worldwide, yet their epidemiology is understudied, and studies investigating multiple pathogens are scarce. Therefore, we selected 316 small ruminants in irrigated, pastoral, and riverine settings in Tana River County and conducted repeated sampling for animals that were initially seronegative between September 2014 and June 2015. We carried out serological and polymerase chain reaction tests and determined risk factors for exposure. The survey-weighted serological incidence rates were 1.8 (95% confidence intervals [CI]: 1.3–2.5) and 1.3 (95% CI: 0.7–2.3) cases per 100 animal-months at risk for Leptospira spp. and C. burnetii, respectively. We observed no seroconversions for Brucella spp. Animals from the irrigated setting had 6.83 (95% CI: 2.58–18.06, p-value = 0.01) higher odds of seropositivity to C. burnetii than those from riverine settings. Considerable co-exposure of animals to more than one zoonosis was also observed, with animals exposed to one zoonosis generally having 2.5 times higher odds of exposure to a second zoonosis. The higher incidence of C. burnetii and Leptospira spp. infections, which are understudied zoonoses in Kenya compared to Brucella spp., demonstrate the need for systematic prioritization of animal diseases to enable the appropriate allocation of resources
A systematic review and meta-analysis of the aetiological agents of non-malarial febrile illnesses in Africa
BackgroundThe awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades. Therefore, we undertook a systematic literature review and meta-analysis of causative agents of non-malarial fevers on the African continent.MethodologyWe searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of Science databases to identify aetiologic agents that had been reported and to determine summary estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever patients.FindingsA total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible. A wide array of aetiologic agents were described with considerable regional differences among the leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest proportion. The summary estimates from the meta-analysis were low for most of the agents. This may have resulted from a true low prevalence of the agents, the failure to test for many agents or the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and population variables showed that diagnostic methods determined the PMr estimates of typhoidal Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of Haemophilus spp. infections.ConclusionThe small number of epidemiological studies and the variety of NMFI agents on the African continent emphasizes the need for harmonized studies with larger sample sizes. In particular, diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public health strategies
Longitudinal Study of Selected Bacterial Zoonoses in Small Ruminants in Tana River County, Kenya
Brucellosis, Q fever, and leptospirosis are priority zoonoses worldwide, yet their epidemiology is understudied, and studies investigating multiple pathogens are scarce. Therefore, we selected 316 small ruminants in irrigated, pastoral, and riverine settings in Tana River County and conducted repeated sampling for animals that were initially seronegative between September 2014 and June 2015. We carried out serological and polymerase chain reaction tests and determined risk factors for exposure. The survey-weighted serological incidence rates were 1.8 (95% confidence intervals [CI]: 1.3-2.5) and 1.3 (95% CI: 0.7-2.3) cases per 100 animal-months at risk for Leptospira spp. and C. burnetii, respectively. We observed no seroconversions for Brucella spp. Animals from the irrigated setting had 6.83 (95% CI: 2.58-18.06, p-value = 0.01) higher odds of seropositivity to C. burnetii than those from riverine settings. Considerable co-exposure of animals to more than one zoonosis was also observed, with animals exposed to one zoonosis generally having 2.5 times higher odds of exposure to a second zoonosis. The higher incidence of C. burnetii and Leptospira spp. infections, which are understudied zoonoses in Kenya compared to Brucella spp., demonstrate the need for systematic prioritization of animal diseases to enable the appropriate allocation of resources
Sero-epidemiological survey of Coxiella burnetii in livestock and humans in Tana River and Garissa counties in Kenya
BackgroundCoxiella burnetii is a widely distributed pathogen, but data on its epidemiology in livestock, and human populations remain scanty, especially in developing countries such as Kenya. We used the One Health approach to estimate the seroprevalance of C. burnetii in cattle, sheep, goats and human populations in Tana River county, and in humans in Garissa county, Kenya. We also identified potential determinants of exposure among these hosts.MethodsData were collected through a cross-sectional study. Serum samples were taken from 2,727 animals (466 cattle, 1,333 goats, and 928 sheep) and 974 humans and screened for Phase I/II IgG antibodies against C. burnetii using enzyme-linked immunosorbent assay (ELISA). Data on potential factors associated with animal and human exposure were collected using a structured questionnaire. Multivariable analyses were performed with households as a random effect to adjust for the within-household correlation of C. burnetii exposure among animals and humans, respectively.ResultsThe overall apparent seroprevalence estimates of C. burnetii in livestock and humans were 12.80% (95% confidence interval [CI]: 11.57–14.11) and 24.44% (95% CI: 21.77–27.26), respectively. In livestock, the seroprevalence differed significantly by species (p ConclusionsThis study provides evidence of livestock and human exposure to C. burnetii which could have serious economic implications on livestock production and impact on human health. These results also highlight the need to establish active surveillance in the study area to reduce the disease burden associated with this pathogen
Surveillance of climate-sensitive zoonotic diseases: Leptospirosis at livestock slaughterhouses in three regions of Uganda
Leptospirosis is an important bacterial zoonosis worldwide and is disproportionately associated with low-income settings and with extreme weather events due to climate change.
Transmission to humans often occurs when infected rodents and domestic animals contaminate the environment via urine as the bacteria preferentially colonise kidneys. Surveillance
of leptospirosis at slaughterhouses can therefore be useful in providing information on vast
areas of a country and screening for diseases that are not considered during animal inspections.
We determined the prevalence of Leptospira bacteria in the kidneys of 2,030 livestock
kidney samples (820 cattle, 761 pigs, 335 goats, 114 sheep), and 117 small mammals by realtime PCR in a cross-sectional survey of slaughter facilities in three regions in Uganda. We
extracted DNA and performed real-time polymerase chain reaction (PCR) tests targeting
the lipL32 gene for pathogenic leptospires. Positive samples with cycle threshold values
below 38 were further characterised using single locus sequence typing (SLST) to determine
likely genomospecies. PCR products were sequenced by Eurofins Genomics (Ebersberg,
Germany) and identification of genomospecies was done using the basic local alignment
search tool (BLAST). Multi-locus sequencing typing (MLST) was performed on selected
SLST-positive samples to determine sequence types (ST) and likely serogroups. The allelic
profiles were analysed using Bionumerics software and the sequence types were determined
using the PubMLST database.
An overall prevalence of pathogenic leptospires of 2.58 % (95 % confidence intervals [CI]:
1.89–3.42) was observed, with sheep having the highest prevalence (6.12 % CI: 2.69–12.89),
followed by cattle (4.25 %, 95 % CI: 2.91–5.98), goats (2.08 %, 95 % CI=0.91–4.38), and pigs
(0.46 %, 95 % CI = 0.12–1.31) in decreasing order. The genomospecies L. borgpetersenii
(11 in cattle and one in goat), L. kirschneri (five in cattle and four in sheep) and L.
interrogans (one in a pig) were determined. Preliminary MLST results on one sample
reveal L. kirschneri ST62 which is related to serogroup Grippotyphosa.
Surveillance of important zoonoses using slaughterhouses as sentinels has the potential to
offer essential information on the epidemiology of important zoonotic diseases in Uganda
Recommended from our members
Molecular and serological diagnosis of multiple bacterial zoonoses in febrile outpatients in Garissa County, north-eastern Kenya
Bacterial zoonoses are diseases caused by bacterial pathogens that can be naturally transmitted between humans and vertebrate animals. They are important causes of non-malarial fevers in Kenya, yet their epidemiology remains unclear. We investigated brucellosis, Q-fever and leptospirosis in the venous blood of 216 malaria-negative febrile patients recruited in two health centres (98 from Ijara and 118 from Sangailu health centres) in Garissa County in north-eastern Kenya. We determined exposure to the three zoonoses using serological (Rose Bengal test for Brucella spp., ELISA for C. burnetti and microscopic agglutination test for Leptospira spp.) and real-time PCR testing and identified risk factors for exposure. We also used non-targeted metagenomic sequencing on nine selected patients to assess the presence of other possible bacterial causes of non-malarial fevers. Considerable PCR positivity was found for Brucella (19.4%, 95% confidence intervals [CI] 14.2–25.5) and Leptospira spp. (1.7%, 95% CI 0.4–4.9), and high endpoint titres were observed against leptospiral serovar Grippotyphosa from the serological testing. Patients aged 5–17 years old had 4.02 (95% CI 1.18–13.70, p-value = 0.03) and 2.42 (95% CI 1.09–5.34, p-value = 0.03) times higher odds of infection with Brucella spp. and Coxiella burnetii than those of ages 35–80. Additionally, patients who sourced water from dams/springs, and other sources (protected wells, boreholes, bottled water, and water pans) had 2.39 (95% CI 1.22–4.68, p-value = 0.01) and 2.24 (1.15–4.35, p-value = 0.02) times higher odds of exposure to C. burnetii than those who used unprotected wells. Streptococcus and Moraxella spp. were determined using metagenomic sequencing. Brucellosis, leptospirosis, Streptococcus and Moraxella infections are potentially important causes of non-malarial fevers in Garissa. This knowledge can guide routine diagnosis, thus helping lower the disease burden and ensure better health outcomes, especially in younger populations
Causes of non-malarial fever in Africa: A systematic review and meta-analysis
Objectives
The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades.
Therefore, we undertook a systematic literature review and meta-analysis of causative agents of
non-malarial fevers on the African continent.
Materials and methods
We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of
Science databases to identify aetiologic agents that had been reported and to determine summary
estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever
patients.
Results
A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible.
A wide array of aetiologic agents were described with considerable regional differences among the
leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest
proportion. The summary estimates from the meta-analysis were low for most of the agents. This
may have resulted from a true low prevalence of the agents, the failure to test for many agents or
the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and
population variables showed that diagnostic methods determined the PMr estimates of typhoidal
Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed
over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of
Klebsiella spp. infections.
Conclusion
The small number of epidemiological studies and the variety of NMFI agents on the African
continent emphasizes the need for harmonized studies with larger sample sizes. In particular,
diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results
and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public
health strategies
"Politics, Africa, and Performance" - Imagining Global Arts Residencies at Haverford and Beyond
Panel discussion held at Haverford College, Chase Auditorium on October 20, 2009."Politics, Africa, and Performance" brings together writers, scholars, performers, and activists in a two-day discussion focusing on the ways in which the visual and performing arts provide crucial links between lived experience and political power. While Africa continues to be seen as underdeveloped, it is often at the forefront of new political movements. For scholars in Anthropology, History, and a range of other fields seeking to make sense of violence and change, dialogues with artists provide keys to understanding the seeming contradictions of populist struggle in today's global world.\ud
\ud
Following the intense post-election violence in Kenya in 2008 as well as the xenophobic violence in South Africa directed at poor urban dwellers from other African countries, writers, filmmakers, and artists have struggled to play a role as social commentators. This discussion will foreground the ways the visual and performing arts can bring power and inequality into the public eye.\ud
\ud
Panelists are Eric Wainaina (writer and performer, Mo Faya!), Mumbi Kaigwa (performer, Mo Faya!), Martin Kimani (Associate Fellow at the Conflict, Security, and Development Group at King’s College, London), Binyavanga Wainaina (Director of the Chinua Achebe Center for African Literature and Languages, Bard College), and Jesse Weaver Shipley (Assistant Professor of Anthropology, African & Africana Studies, Haverford College)