Background: Hypertension, a major risk factor for cardiovascular disease is rapidly attaining epidemic portions in Africa and is strongly associated with urbanisation. We studied a population of Kenyans of Somali ethnicity; traditionally a semi nomadic pastoralist community but who have settled in local urban centres and thereby subject to lifestyle influences of urbanisation. This represents a unique position in the epidemiological transition.

Methods: A cross-sectional community survey carried out in Garissa town, the administrative centre for North Eastern Province, with a population of 196,062. Utilising cluster sampling 2200 adults were recruited. WHO STEPS questionnaire was followed by measurement of BP; height and weight for BMI; waist and hip circumference. Non fasting blood specimens were taken for random blood sugar and total cholesterol.

Results: Data for 1823 subjects, 702 males, 1121 females were complete and analysed. Mean age was 38.5 (range 18-96 years), 82% less than 50 years. Hypertension prevalence was 12.6% (95% CI 11.1-14.2%) and increased with age reaching 38.5 % in over 65years; with a 61% detection rate. Concurrent risk factors were: diabetes 3.7% (2.9-4.7); Overweight 23.9% (21.9-25.9%), Obesity 12.6% (11.2-14.3%), Abdominal obesity (WHR)20.4% (18.5-22.3%), Smoking 5.2% (4.4-6.5%) and hypercholesterolemia 16.9%(11.0-24.3%). Male sex, increasing age, diabetes and over weight were independently associated with hypertension.

Discussion: Despite the young age, this unique and previously unstudied urban & semi-urban population has a high prevalence of hypertension and cardiovascular risk factors showing evidence of epidemiological transition to NCDs. There is opportunity for primary prevention.

There is a global dimension to lake management in Africa and elsewhere that will require a concerted action not only from individual riparian states, but also from regional, continental and global communities. The current global lake threats arise from climate change, regional land degradation and semivolatile contaminants, and share the common feature that the atmosphere is the vector that spreads their impacts over large areas and to many lakes. The Great Lakes of Africa (Malawi, Victoria and Tanganyika) are particularly sensitive to these problems because of their enormous surface areas, slow water flushing rates, and the importance of direct rainfall in their water budgets. Their response times might be slow to yield a detectable change and, unfortunately, their recovery times might also be slow. It is possible for atmospheric effects to act antagonistically to the impacts of catchment change, but antagonistic effects could become synergistic in the future. Improved understanding of the physical dynamics of these lakes, and development of models linking their physical and biogeochemical behaviour to regional, mesoscale climate models, will be necessary to guide lake managers.

The identification of five novel compounds, pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-N-demethylerythromycin A-6,9-hemiketal, 5-O-beta-D-desosaminylerythronolide A and 15-nor-erythromycin C, in mother liquor concentrates of Streptomyces erythraeus is described. The pseudo-erythromycin derivatives are characterized by a 12-membered macrocyclic ring as a result of C13––C11 trans-lactonization. The five compounds have very little antimicrobial activity.

Information and Communication Technologies have been identified as major catalysts to rapid and sustainable development, especially in today's information-driven economies. The provision of timely, accurate and relevant information to the masses should therefore be a prime consideration in any development agenda. For this information to have an effective developmental impact, it must be presented in the language that the populace is most proficient in, usually the language(s) commonly spoken in day to day life. The language factor should therefore be recognized as a critical success factor in the deployment of ICTs for development, especially in the areas of education, health and governance. While Africa is home to a third of all the world's languages, the “information languages” on the continent are more often than not, European languages, namely English, French and Portuguese, which are by and large, languages of the educated elite. This has had the adverse effect of locking out a huge percentage of Africa's populace from effectively participating in the increasingly information-based economies. This paper discusses how language technology can be exploited to support the development of relevant local content that addresses and satisfies the multilingual requirements deriving from the continent's linguistic and cultural diversity, effectively reducing the language barrier to technology that exists especially among Africa's rural populations.

The genetic history of African cattle pastoralism is controversial and poorly understood. We reveal the genetic signatures of its origins, secondary movements, and differentiation through the study of 15 microsatellite loci in 50 indigenous cattle breeds spanning the present cattle distribution in Africa. The earliest cattle originated within the African continent, but Near East and European genetic influences are also identified. The initial expansion of African Bos taurus was likely from a single region of origin. It reached the southern part of the continent by following an eastern route rather than a western one. The B. indicus genetic influence shows a major entry point through the Horn and the East Coast of Africa and two modes of introgression into the continent.

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An Instructional Manual for teaching African Philosophy to second year students in the department of philosophy, University of Nairobi

Introduction to Philosophy of Religion, University of Nairobi, 1988

In large parts of Africa, wildlife herbivores spill over onto private lands, competing with domestic livestock for forage resources. To encourage private landowners to take into account the externality benefits of wildlife, game cropping is increasingly considered as an important component of conservation policies. In this paper, we employ a bioeconomic model of a private game ranch to examine five potential government policies concerning wildlife conservation, ranging from (strict) preservation to uncontrolled exploitation. 'Intermediate' policies appear to contribute most to wildlife conservation, with costs to landowners of such policies being modest. The model outcomes support recent wildlife policy shifts in Kenya.

Journal of Eastern African Literary and Cultural Studies

Background: Hepatitis C Virus (HCV)
infection is a worldwide burden whose
seroprevalence is higher in developing countries with Cameroon being the
third most aff ected country in Africa.
HCV both a hepatotropic and lympho-
tropic infection is responsible for a great
number of hepatic and extra hepatic
disorders some of which are rheumatic
in nature. These rheumatologic mani-
festations though extensively studied
in western countries; there is little or no
data in sub-Saharan Africa.
Objective: The study was conducted
with the aim to describe the musculo-
skeletal manifestations associated to
HCV infection in a hospital setting in
Cameroon.
Design: A cross-sectional study.
Setting: Three hospitals in Cameroon:
the Douala General Hospital, a tertiary
referral hospital with a capacity of 320
beds in Douala, the largest city and
economic capital of Cameroon; the
University Teaching Hospital of the
Faculty of Medicine and Biomedical
Sciences of the university of Yaoundé
1, a 240 beds hospital in Yaoundé the
political capital of Cameroon and the
“Centre Médical de la Cathédrale”,
a private acceptable standard
Gastroenterology clinic also found in
Yaoundé.
Patients and methods: From February
to June 2009, we did a multicentric
cross-sectional study of patients from
the Gastroenterology, Rheumatology
and Internal medicine outpatient clinics
of three hospitals in Cameroon. Patients
with HIV or HBV infection and those on
antiviral treatment were excluded.
Results: Among 148 patients with HCV
infection identifi ed during the study
period, only 62 fulfi lled eligibility, 15
(24.2%) of whom had musculoskeletal
manifestations related to HCV, the
commonest of which were myalgia
9/62 (14.5%) , arthritis 6/62 (9.7%), bone
pain 6.4% (4/62), sicca syndrome 3/62
(4.8%), and Raynaud’s phenomenon
6/62 (9.7%). Among patients with
rheumatologic manifestations, 9/15
(60%), had rheumatologic symptoms at
HCV diagnosis and in 6/15 (40%). HCV
infection was discovered during routine
medical check-up. Musculoskeletal
manifestations were neither associat ed
with the genotype (p=0.17) nor with the
viral load (p>0.98).
Conclusion: Arthralgia is the most
common presenting feature of the
symptomatic disease. Musculoskeletal
manifestations may be confused with symptoms of common tropical infections, leading to delayed diagnosis
and treatment of HCV infection.
Key words: Hepatitis C Virus, Arthralgia,
Extra hepatic manifestations; Africa
Introduction
Hepatitis C Virus (HCV) infection
which occurs worldwide has a higher
seroprevalence in Africa, estimated
at 5.3% compared to about 1.03%
in Europe1,2. Cameroon, the third
most affected country in Africa, has a
seroprevalence which varies from as low
as 0.6% to 4.8% in Pygmy groups and
blood donors, to as high as 13% in hospital
based studies4,5. Hepatitis C virus (HCV)
which is a single-stranded, spherical RNA enveloped fl avivirus, measuring 38 to 50
nm in diameter has multiple genotypes
and quasispecies classifi ed in six major
clades. This genetic diversity confers to
this virus a difference in pathogenicity,
disease severity, and response to treatment
with interferon3. Though considered a
hepatotropic virus, HCV’s lymphotropic
nature is responsible for a great number of
extra hepatic immune system disorders1.
About 40 to 70% of affected patients will
develop an extra hepatic manifestation
that can have a rheumatic nature

The Afya Bora Consortium is a partnership of 8 academic health institutions, 4 in Africa and 4 in the United States. The Consortium is developing a Global Health Leadership Fellowship for medical, nursing, and public health professionals, largely drawn from the 4 African partner countries. The fellowship provides trainees with practical skills to prepare them for future positions leading the design, implementation, and evaluation of large, high-impact programs in governmental agencies, nongovernmental organizations, and academic health institutions in their own countries. This article describes a Pilot of the proposed program.

The genetic model previously proposed for tsavorite- (and tanzanite-) bearing mineralization hosted in the Neoproterozoic Metamorphic Mozambique Belt (stretching from Kenya through Tanzania to Madagascar) is refined on the basis of new Sm-Nd age determinations and detailed Sr-O-S isotope and fluid-inclusion studies. The deposits are hosted within meta-sedimentary series composed of quartzites, graphitic gneisses, calc-silicate rocks intercalated with meta-evaporites, and marbles. Tsavorite occurs either in nodules (also called “boudins”) oriented parallel to the metamorphic foliation in all of the deposits in the metamorphic belt or in quartz veins and lenses located at the hinges of anticlinal folds (Lelatema fold belt and Ruangwa deposits, Tanzania). Gem tanzanite occurs in pockets and lenses in the Lelatema fold belt of northern Tanzania.

The Sm-Nd isotopic data for tsavorites and tanzanites hosted in quartz veins and lenses from Merelani demonstrate that they formed at 600 Ma, during the retrograde metamorphic episode associated with the East African Orogeny. The tsavorites hosted in nodules do not provide reliable ages: their sedimentary protoliths had heterogeneous compositions and their Sm-Nd system was not completely rehomogenized, even at the local scale, by the fluid-absent metamorphic recrystallization.

The initial 87Sr/86Sr isotopic ratios of calcite from marble and tanzanites from Merelani fit with the strontium isotopic composition of Neoproterozoic marine carbonates. Seawater sediment deposition in the Mozambique Ocean took place around 720 Ma.

The quartz-zoisite O-isotopic thermometer indicates a temperature of formation for zoisite between 385 and 448 °C.

The sulfur isotopic composition of pyrite (between –7.8 and –1.3‰ V-CDT) associated with tsavorite in the Lelatema fold belt deposits suggests the contribution of reduced marine sulfate. The sulfur in pyrite in the marbles was likely derived from bacterial sulfate reduction which produced H2S. Fluid inclusion data from tsavorite and tanzanite samples from the Merelani mine indicate the presence of a dominant H2S-S8±(CH4)±(N2)±(H2O)-bearing fluid. In the deposits in Kenya and Madagascar, the replacement of sulfate by tsavorite in the nodules and the boron isotopic composition of tourmaline associated with tsavorite are strong arguments in favor of the participation of evaporites in garnet formation.

Atrioventricular annuli are important in hemodynamic stability and support to tricuspid and mitral valves. Anatomical features of the annuli such as circumference, organization of connective tissue fibers, myocardium and cellularity may predispose to annular insufficiency and valvular incompetence. These pathologies increase with age and are more common in females, although the anatomical basis for this disparity remains unclear. This study therefore aimed to investigate age-related changes in the structure of human atrioventricular annuli. One hundred and one hearts (48males, 53 females) from subjects (15 to 60 years) were studied in three age groups (≤ 20 yrs, 21-39 yrs and 40-60 yrs). Annular circumferences were measured and corrected for heart weight. Routine histology was carried out on 21 hearts. Differences in annular circumference between the age groups were determined using one-way ANOVA while gender differences were determined using independent Students’t-test. Overall, females had significantly larger annular circumference than males after correcting for heart weight (p ≤0.05). The annular circumference generally increased with age however there was a significant increase in the 21-39 year age group (p ≤0.05). Microscopically, myocardium was consistently present in males but absent in females except in one specimen. The collagen fiber density increased with age in both gender as the fibers became more irregular. The annular cellularity, elasticity and myocardial content also declined with increasing age. The significantly wider annular circumference in the 21-39 year age group is clinically important as wider circumference is associated with decreased heart valve co-aptation and valvular incompetence. This may suggest an earlier predisposition to this pathology in the study population. The age-related decrease in annular cellularity, elasticity and myocardial content may explain the higher incidence of valvular incompetence with increasing age.

Age changes in the aortic tunica intima may explain the higher prevalence of atherosclerosis among the elderly. Goat is a suitable model for the study of cardiovascular disease but the age changes in its aortic tunica intima are unreported. This study therefore examined structural changes that occur in the tunica intima of its aorta. Six healthy goats three aged over 60 months, and three aged less than 12 months, were used in this study. The animals were euthanized with sodium pentabarbitone and specimens taken from the various segment of the aorta studied by light microscopy and transmission electron microscopy. Materials for light microscopy were fixed 10% formaldehyde solution, processed for paraffin embedding and 7 micron sections stained with Mason’s Trichrome and Weigert’s Resorcin Fuchsin/Van Gieson stains. Those for transmission electron microscopy were fixed in 3% phosphate buffered glutaraldehyde solution, post fixed in osmium tetroxide and prepared for durcupan embedding. Ultrathin sections were stained with uranyl acetate, counterstained with lead citrate and examined by EM 201 phillips© electron microscope. Observations reveal that aging is characterized by endothelial discontinuities, presence of lymphocytes and dendritic cells in the tunica intima, subendothelial thickening, vacuolation and disintegration of internal elastic lamina. It is concluded that the intimal breaches observed in intimal aging may promote ingression of macromolecules into the vessel wall, and underpin the higher prevalence of atherosclerosis among the elderly. Control of serum atherogenic molecules should be enhanced in this age group.

Age changes in the aortic tunica intima may explain the higher prevalence of atherosclerosis among the elderly. Goat is a suitable model for the study of cardiovascular disease but the age changes in its aortic tunica intima are unreported. This study therefore examined structural changes that occur in the tunica intima of its aorta. Six healthy goats three aged over 60 months, and three aged less than 12 months, were used in this study. The animals were euthanized with sodium pentabarbitone and specimens taken from the various segment of the aorta studied by light microscopy and transmission electron microscopy. Materials for light microscopy were fixed 10% formaldehyde solution, processed for paraffin embedding and 7 micron sections stained with Mason’s Trichrome and Weigert’s Resorcin Fuchsin/Van Gieson stains. Those for transmission electron microscopy were fixed in 3% phosphate buffered glutaraldehyde solution, post fixed in osmium tetroxide and prepared for durcupan embedding. Ultrathin sections were stained with uranyl acetate, counterstained with lead citrate and examined by EM 201 phillips© electron microscope. Observations reveal that aging is characterized by endothelial discontinuities, presence of lymphocytes and dendritic cells in the tunica intima, subendothelial thickening, vacuolation and disintegration of internal elastic lamina. It is concluded that the intimal breaches observed in intimal aging may promote ingression of macromolecules into the vessel wall, and underpin the higher prevalence of atherosclerosis among the elderly. Control of serum atherogenic molecules should be enhanced in this age group.

AIMS:

Peak left ventricular (LV) relaxation normally precedes peak filling (E), which supports the hypothesis that LV suction contributes to early-diastolic filling. The significance of similar temporal discordance in late diastole has previously not been studied. We describe the time relationships between mitral annular motion and LV filling in early and late diastole and examine the effect of normal ageing on these time intervals.

METHODS AND RESULTS:

A total of 128 healthy subjects aged 25-88 years were studied. Transmitral and pulmonary venous flow reversals (Ar) were recorded by Doppler echocardiography. Mitral annular diastolic displacement-early (E(m)) and late (A(m))-were recorded by Doppler tissue imaging. With reference to electrocardiographic R and P-waves, the following measurements were made: R to peak E-wave (R-E) and E(m) (R-E(m)); onset P to peak A-wave (P-pA), A(m) (P-pA(m)), and Ar (P-pAr). The differences between [(R-E) and (R-E(m))] for early-diastolic temporal discordance (EDTD) and [(P-A) and (P-A(m))] for late-diastolic temporal discordance (LDTD) were calculated. Isovolumic relaxation time (IVRT) was also measured. Early-diastolic temporal discordance was approximately 26 ms in all age groups. Late-diastolic temporal discordance, however, was inversely related to age (r = -0.35, P < 0.001) and IVRT (r = -0.34, P < 0.001) and therefore decreased in the elderly vs. young (13 +/- 10 vs. 23 +/- 10 ms; P < 0.001). In multivariate analysis, age failed to predict LDTD in the presence of IVRT. A, A(m), and Ar were simultaneous at onset, and peak A(m) coincided with peak Ar in all age groups (r = 0.97, P < 0.001). No significant differences were noted in the RR intervals.

CONCLUSIONS:

Sequential prolongation of IVRT with ageing reduces LDTD, thus converging the peaks of A(m), A, and Ar (atrial mechanical alignment)-a potential novel method to identify subjects at increased dependency on atrial contraction for late-diastolic filling

BACKGROUND Short monocular deprivation (4 days) induces a shift in the ocular dominance of binocular neurons in the juvenile mouse visual cortex but is ineffective in adults. Recently, it has been shown that an ocular dominance shift can still be elicited in young adults (around 90 days of age) by longer periods of deprivation (7 days). Whether the same is true also for fully mature animals is not yet known. METHODOLOGY/PRINCIPAL FINDINGS We therefore studied the effects of different periods of monocular deprivation (4, 7, 14 days) on ocular dominance in C57Bl/6 mice of different ages (25 days, 90-100 days, 109-158 days, 208-230 days) using optical imaging of intrinsic signals. In addition, we used a virtual optomotor system to monitor visual acuity of the open eye in the same animals during deprivation. We observed that ocular dominance plasticity after 7 days of monocular deprivation was pronounced in young adult mice (90-100 days) but significantly weaker already in the next age group (109-158 days). In animals older than 208 days, ocular dominance plasticity was absent even after 14 days of monocular deprivation. Visual acuity of the open eye increased in all age groups, but this interocular plasticity also declined with age, although to a much lesser degree than the optically detected ocular dominance shift. CONCLUSIONS/SIGNIFICANCE These data indicate that there is an age-dependence of both ocular dominance plasticity and the enhancement of vision after monocular deprivation in mice: ocular dominance plasticity in binocular visual cortex is most pronounced in young animals, reduced but present in adolescence and absent in fully mature animals older than 110 days of age. Mice are thus not basically different in ocular dominance plasticity from cats and monkeys which is an absolutely essential prerequisite for their use as valid model systems of human visual disorders.

Background Short monocular deprivation (4 days) induces a shift in the ocular dominance of binocular neurons in the juvenile mouse visual cortex but is ineffective in adults. Recently, it has been shown that an ocular dominance shift can still be elicited in young adults (around 90 days of age) by longer periods of deprivation (7 days). Whether the same is true also for fully mature animals is not yet known. Methodology/Principal Findings We therefore studied the effects of different periods of monocular deprivation (4, 7, 14 days) on ocular dominance in C57Bl/6 mice of different ages (25 days, 90–100 days, 109–158 days, 208–230 days) using optical imaging of intrinsic signals. In addition, we used a virtual optomotor system to monitor visual acuity of the open eye in the same animals during deprivation. We observed that ocular dominance plasticity after 7 days of monocular deprivation was pronounced in young adult mice (90–100 days) but significantly weaker already in the next age group (109–158 days). In animals older than 208 days, ocular dominance plasticity was absent even after 14 days of monocular deprivation. Visual acuity of the open eye increased in all age groups, but this interocular plasticity also declined with age, although to a much lesser degree than the optically detected ocular dominance shift. Conclusions/Significance These data indicate that there is an age-dependence of both ocular dominance plasticity and the enhancement of vision after monocular deprivation in mice: ocular dominance plasticity in binocular visual cortex is most pronounced in young animals, reduced but present in adolescence and absent in fully mature animals older than 110 days of age. Mice are thus not basically different in ocular dominance plasticity from cats and monkeys which is an absolutely essential prerequisite for their use as valid model systems of human visual disorders.

The process of carcinogenesis is complicated and in most cases requires several steps of cellular transformation resulting from various molecular signals brought about by interactions between carcinogens and the cellular genome. Cancers in which cellular transformation does not require numerous processes tend to occur in younger age groups while cancers of the advancing age tend to be those in which the process of cellular transformation occurs through complex molecular processes that require ample time for induction.

We present two cases of neurofibromatosis type 1 (NF-1), one a 35 year old male who first recognised his problem at the age of fifteen years and at the time of assessment, satisfied the National Institute of Health (NIH) diagnostic criteria for NF-1 and had a nodular plexiform neurofibroma involving the left fifth dorsal nerve root and a diffuse plexiform neurofibroma involving the left lower limb. The second patient, a 45 year old female recognised her problem at the age of 39 years, did not quite satisfy the NIH diagnostic criteria for NF 1 and had diffuse plexiform neurofibroma involving both lower limbs and buttocks almost symmetrically, a finding which has not previously been described to the best of our knowledge. The scarcity of management options are briefly outlined.

Journal of Eastern African Literary and Cultural Studies

This case report presents a 26 year old man who had a history of childhood onset seizures, mild cognitive slowing and social withdrawal. He gradually developed symptoms of depression and attempted suicide once. He presented to the authors following a recurrence of his seizures. On examination they noted a normal general and neurological examination apart from some frontal lobe signs on mental status examination. He also had features of psychosis and labile mood. On CT brain scan he had agenesis of the corpus callosum (CC) with associated interhemispheric cyst and right frontal pachygyria. The authors suggest that clinicians in developing countries should be alert to organic disorders presenting with psychiatric symptoms.

Abstract:
The Information Technology industry has been very dynamic in health insurance for the last couple of decades. In this health insurance firms applications have been developed using different methodologies, and technologies. These applications cannot be integrated, which becomes an issue to health insurance interoperability. Health insurance is available to both individual and groups; there are many insurance companies in Kenya and there is no central database to extract stratified information about them. Attempts by many scholars to develop an interoperable system have not been successful largely due to lack of expertise, resources and the inherent complex nature of the health insurance system. There is also difficulty in accessing the required data by different people due to the fact that the applications of these insurance firms are independent. They are designed in any manner, and can use different technologies. This study proposed an agent-based platform which allowed users to receive and exchange data and information from distributed sources. The health insurance business was used as a case study to implement multi-agents approach in this study. In this case study, different agents were used to represent different functional areas in the developed system. The reactivity, proactive, sociability characteristics of multi-agents achieved health insurance interoperability and accomplished the health insurance business requirements. In this study we reviewed pure theory, evaluated and developed an agent based system which allowed health insurance firms to share data and also data sharing platform that enabled collaboration among multiple health insurance institutions in Kenya and also the experimental results showed that the platform could be extended easily to support a large number of concurrent client connections.

While most governments, including the government of Kenya, have improved their performance through allowing more information exchange using web support, there is increased spread of information crimes targeting government web applications. Structured Query Language (SQL) injection and Cross Site Scripting attack (XSS) are ranked as the two top most vulnerability attacks by the Open Web Application Security Project (OWASP) top 10, 2013 vulnerability list. Recently there have been massive attacks on a number of websites including the government of Kenya. Agent orientation is emerging as a dominant research area and as a new paradigm in provision of solutions to problems. Agents provide developers and designers with a way of structuring applications around autonomous and communicative elements. In this paper, we present a solution that uses multi-agents to detect both SQL injection and XSS attacks vulnerabilities on web applications. The system has been developed using Java programming language and Prometheus methodology as an Agent Oriented Software. It will specifically target websites in development environment
for testing the vulnerabilities before being hosted in the production environment. We have also incorporated the testing of already hosted websites for the two vulnerabilities. The proposed system will help web developers and owners of websites to fix the vulnerabilities and enhance the entire security.

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The study was conducted at Thika and Kiambu District Hospitals Medical wards covering September 2005

OBJECTIVE: This study aimed to determine the extent of agreement between central venous and arterial values for pH, bicarbonate, base excess, and lactate in a group of intensive care unit (ICU) patients. METHODS: A prospective study of a convenience sample of patients deemed by their treating doctor to require blood gas analysis as part of their clinical care in ICU. It compared pH, bicarbonate, base excess and lactate on arterial and central venous samples taken within five minutes of each other. Data were analysed using bias (Bland-Altman) methods. RESULTS: A total of 168 matched sample pairs from 110 patients were entered into the study. All variables showed close agreement. The mean difference between arterial and venous values of pH was 0.03 pH units, for bicarbonate 0.52 mmol/l, for lactate 0.08 mmol/l, and for base excess 0.19 mmol/l. All showed acceptably narrow 95% limits of agreement. CONCLUSION: Central venous pH, bicarbonate, base excess, and lactate values showed a high level of agreement with the respective arterial values, with narrow 95% limits of agreement. These results suggest that venous values may be an acceptable substitute for arterial measurement in this clinical setting.

This paper studies the problem of malaria control in irrigation and non-irrigation areas in Kenya. Empirical results show that in both areas, households' level of awareness of malaria as a health problem, including its cause, was very high. However, attempts to trace the direct effects of malaria upon income or upon agricultural production were not statistically important. This does not imply that malaria has no consequence on household welfare. It is possible that the model equations were mis-specified–aggregate variables (total family size, total family income) and failure to quantify land in the production relationships may have contributed to these results. In addition, poor separation of malaria as a disease, from malaria as an infection, may have underestimated the effect of the disease on production. Thirdly, labour substitution (hiring or within-family substitution) was not measured in this early study, but was taken into account in subsequent research. Finally, labour requirements in the annual crop production schedules and the co-relation between these labour requirements and the pattern of adult morbidity were not longitudinally monitored. Cross-section data would bias the findings, particularly in those areas where the peak transmission season is short, where the crop grown does not require major labour input during this transmission season, and where acquisition of immunity would reduce the clinical impact of malaria upon adult labour. These vulnerabilities in the specification of the model and the data collected, probably affect the results obtained. Our empirical work raises a number of interesting and important questions which should be taken into account in future research

Among the nitrogen (N2)-fixing bacteria, the rhizobia in symbiosis with legumes are generally the most important in agriculture, although Frankia, cyanobacteria and heterotrophic free-living N2 -fixers may fix significant amounts of nitrogen under specific conditions. The taxonomy of N2-fixing bacteria is undergoing substantial revisions due to the advent of molecular methods for phylogenetic analysis, and in certain cases this has proved useful in unravelling ecological relationships among confusing groups. Molecular methods are also proving useful in studies of biodiversity within populations of rhizobial species. Rhizobia are surprisingly competent free-living bacteria, although few fix nitrogen in the free-living state, and the major factors that determine their population sizes in the absence of legume hosts are environmental stresses (such as soil acidity factors), protozoal grazing and some factors associated with agricultural intensification such as increases in salinity or heavy metal pollution of the soil. Rhizobial populations generally increase in response to the presence of the host legume. Due to the high degree of host-specificity between legume hosts and rhizobial species, loss of a single rhizobial species can result in loss of N2-fixation by that legume, although many legumes can be nodulated by several species of rhizobia. However, as only a single, compatible rhizobial genotype or strain is necessary for establishment of effective N, -fixation (i.e. the basis of the rhizobial inoculant industry), it is questionable whether biodiversity within species is necessary to ensure function, although this may confer resilience in the face of further environmental stresses.