ABSTRACT A suite of sediment samples from the Romanche Fracture Zone in the equatorial Atlantic has been subjected to bulk and partition chemical and mineralogical analyses, together with radiometric dating, in order to study the main controls on composition and origin.The interelement relationships in the sediments revealed by geostatistical analysis indicate that (1) Ca, Sr and P, (2) Al, Fe, Ti, V, Zn, Li, Be and K, (3) Mn, Co, Ni and Cu and (4) Mg, Cr and Ni are associated. Partition chemical data suggest that these element associations represent respectively biogenic, terrigenous, igneous and hydrogenic phases of the sediment.Surface and downcore sediment data indicate that the distribution of the biogenic component of the sediment is influenced by water depth. The distribution of the igneous component is largely controlled by a contribution from ultramafic sources and shows the influence of subsea erosion on the surface sediments. The distribution of the hydrogenic component is influenced by contribution from the water column. Sediment accumulation rate data indicate that these sediments have accumulated fairly rapidly. Bottom topography and turbidity current activity are probably the main factors controlling their accumulation. Metal accumulation rate data indicate that there is no significant hydrothermal contribution to the deposits as has been suggested by other workers.

OBJECTIVE: To study re-association pattern of human placental eluate immunoglobulins with acid treated isologous and third party trophoblast derived placental microvesicles. DESIGN: Laboratory based experimentation. SETTING: Biological Sciences Department and Discipline for Reproductive Medicine University of Newcastle, Australia and the Department of Biochemistry, University of Nairobi, Kenya. RESULTS: Placental eluate immunoglobulins re-associated with isologous and third party acidified microvesicles in three distinct patterns. I: eluate immunoglobulins re-associated more strongly with isologous and third party acid treated placental microvesicles, II: eluate immunoglobulins re-associated strongly with isologous but weakly with third party acid treated placental microvesicles, III: eluate immunoglobulins did not show preferential re-association with isologous and third party acid treated placental microvesicles. CONCLUSION: Two types of antigenic epitopes I and II may be expressed on the human placentae. Type I antigens may be present on all human placentae while type II epitopes may be paternally derived hence unique to each pregnancy. Also, immunoglobulins produced to placental microvesicle antigens may be directed to some but not all antigenic epitopes expressed on the human placental trophoblast.

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Recurrent pregnancy loss has been associated with autoimmune responses to membrane phospholipids and alloimmune reactions against paternally derived molecules on the trophoblast. The problem is psychologically and economically stressful as it undermines the capacity of some couples to reproduce and participate effectively in the day-to-day economic activities. This article reviews the adoption of intravenous immunoglobulin as a form of therapy for the clinical management of recurrent pregnancy loss and of selected autoimmune disorders. Side effects, contraindications and safety of use are discussed.

Recurrent pregnancy loss has been associated with autoimmune responses to membrane phospholipids and alloimmune reactions against paternally derived molecules on the trophoblast. The problem is psychologically and economically stressful as it undermines the capacity of some couples to reproduce and participate effectively in the day-to-day economic activities. This article reviews the adoption of intravenous immunoglobulin as a form of therapy for the clinical management of recurrent pregnancy loss and of selected autoimmune disorders. Side effects, contraindications and safety of use are discussed.

The East African Rift (EAR) is an active continental rift and ideal to investigate the processes of rift initiation and the breaking apart of continental lithosphere. Mantle and crust-derived fluids may play a pivotal role in both magmatism and faulting in the EAR. For instance, large quantities of mantle-derived volatiles are emitted at Oldoinyo Lengai volcano [1, 2]. Throughout the EAR, CO2-dominated volatile fluxes are prevalent [3, 4] and often associated with faults (i.e. Rungwe area, Tanzania, [5, 6]). The purpose of this study is to examine the relationship between volcanism, faulting and the volatile compositions, focusing on the central and southern Kenyan and northern Tanzanian section of the EAR. We report our analysis results for samples obtained during a 2013 field season in Kenya. Gases were sampled at fumaroles and geothermal plants in caldera volcanoes (T=83.1-120.2°C) and springs (T=40-79.6°C and pH 8.5-10) located near volcanoes, intra-rift faults, and a transverse fault (the Kordjya fault, a key fluid source in the Magadi rift) by 4N-NaOH solution-filled and empty Giggenbach bottles. Headspace gases were analyzed by a Gas Chromatograph and a Quadrupole Mass Spectrometer at the University of New Mexico. Both N2/Ar and N2/He ratios of all gases (35.38-205.31 and 142.92-564,272, respectively) range between air saturated water (ASW, 40 and ≥150,000) and MORB (100-200 and 40-50). In addition, an N2-Ar-He ternary diagram supports that the gases are produced by two component (mantle and air) mixing. Gases in the empty bottles from volcanoes and springs have N2 (90.88-895.99 mmom/mol), CO2 (2.47-681.21 mmom/mol), CH4 (0-214.78 mmom/mol), O2 (4.47-131.12 mmom/mol), H2 (0-35.78 mmom/mol), Ar (0.15-10.65 mmom/mol), He (0-2.21 mmom/mol), and CO (0-0.08 mmom/mol). Although some of the samples show an atmospheric component, CO2 is a major component in most samples, indicating both volcanoes and springs are emitting CO2. Gases from volcanoes are enriched in CH4 and H2, denoting their sources are reduced (oxygen-poor) magma chambers or hydrothermal systems. 40Ar/36Ar ratios (average of all samples=299.15) are similar to our air standard value (299.65×4.05), however, some volcanoes (~308.75) and springs (~321.96) have slightly higher ratios. The springs with elevated 40Ar imply that both the intra-rift (Lake Bogoria) and transverse (Lake Magadi) faults are possibly pathways to carry volatiles from deep sources to the surface. In future work, we will carry out wet chemistry and ion chromatography analyses of the NaOH solutions, measure 3He/4He ratios and complete C, N, and S isotope analyses to further constrain fluid sources and migration processes. [1] Fischer et al., 2009, Nature 459. [2] de Moor et al., 2013, EPSL 361. [3] Sawyer et al., 2008, G-cubed 9. [4] Tassi et al., 2009, G-cubed 10. [5] Barry et al., 2013, Chem Geol 339. [6] de Moor et al., 2013, Chem Geol 339.

Artemisinin resistant Plasmodium falciparum is advancing across Southeast Asia in a soft selective sweep involving at least 20 independent kelch13 mutations. In a large global survey, we find that kelch13 mutations which cause resistance in Southeast Asia are present at low frequency in Africa. We show that African kelch13 mutations have originated locally, and that kelch13 shows a normal variation pattern relative to other genes in Africa, whereas in Southeast Asia there is a great excess of non‐synonymous mutations, many of which cause radical amino‐acid changes. Thus, kelch13 is not currently undergoing strong selection in Africa, despite a deep reservoir of standing variation that could potentially allow resistance to emerge rapidly. The practical implications are that public health surveillance for artemisinin resistance should not rely on kelch13 data alone, and interventions to prevent resistance must account for local evolutionary conditions, shown by genomic epidemiology to differ greatly between geographical regions.

Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigen-coding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi.

Once digitized and edited GIS data are stored in a spatial database. Evidently, the quality of the decisions made from a GIS will depend on the quality of the data contained in the database. A spatial database is defined as a pool of integrated and structured geospatial data, which is a model of reality, and from which data may be retrieved to provide useful information to users. Hence, a spatial database is comprised of inter-related geospatial data that is maintained efficiently and which is shareable between different GIS applications.

Understanding the characteristics of and possibilities in using geodata is premised on proper comprehension of the underlying concepts of space, time and scale, contextualized within the Earth’s framework. Although these concepts are used in everyday parlance, often without much afterthought, they are not trivial at all. For instance, looking back throughout the entire history of mankind, the concepts of space and time have been the subject of animated philosophical, religious and scientific debates. In this section, we attempt to present a background of each of these dimensions of geodata, both independently and collectively, as well as highlight their relevance in influencing the character of geodata.

The Global Positioning System or GPS is the oldest and most widely used GNSS system, and as such will be extensively discussed in this and the next chapter. The development of GPS satellites dates from the 1960s.

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High plasma HIV-1 RNA concentrations are associated with an increased risk of HIV-1 transmission. Although plasma and genital HIV-1 RNA concentrations are correlated, no study has evaluated the relationship between genital HIV-1 RNA and the risk of heterosexual HIV-1 transmission. In a prospective study of 2521 African HIV-1 serodiscordant couples, we assessed genital HIV-1 RNA quantity and HIV-1 transmission risk. HIV-1 transmission linkage was established within the partnership by viral sequence analysis. We tested endocervical samples from 1805 women, including 46 who transmitted HIV-1 to their partner, and semen samples from 716 men, including 32 who transmitted HIV-1 to their partner. There was a correlation between genital and plasma HIV-1 RNA concentrations: For endocervical swabs, Spearman's rank correlation coefficient ρ was 0.56, and for semen, ρ was 0.55. Each 1.0 log(10) increase in genital HIV-1 RNA was associated with a 2.20-fold (for endocervical swabs: 95% confidence interval, 1.60 to 3.04) and a 1.79-fold (for semen: 95% confidence interval, 1.30 to 2.47) increased risk of HIV-1 transmission. Genital HIV-1 RNA independently predicted HIV-1 transmission risk after adjusting for plasma HIV-1 quantity (hazard ratio, 1.67 for endocervical swabs and 1.68 for semen). Seven female-to-male and four male-to-female HIV-1 transmissions (incidence <1% per year) occurred from persons with undetectable genital HIV-1 RNA, but in all 11 cases, plasma HIV-1 RNA was detected. Thus, higher genital HIV-1 RNA concentrations are associated with greater risk of heterosexual HIV-1 transmission, and this effect was independent of plasma HIV-1 concentrations. These data suggest that HIV-1 RNA in genital secretions could be used as a marker of HIV-1 sexual transmission risk.

A succinct, up-to-date, and clinically relevant review of human physiology – trusted by generations of students and clinicians More than 600 full-color illustrations For more than four decades, Ganong’s Review of Medical Physiology has been helping those in the medical field understand human and mammalian physiology. Applauded for its interesting and engagingly written style, Ganong’s concisely covers every important topic without sacrificing depth or readability and delivers more detailed, high-yield information per page than any other similar text or review. Thoroughly updated to reflect the latest research and developments in important areas such as chronic pain, reproductive physiology, and acid-base homeostasis. Ganong’s Review of Medical Physiology incorporates examples from clinical medicine to illustrate important physiologic concepts. Whether you’re a student who needs an outstanding review for the USMLE or a physician who wants to keep pace with the ever-changing field of medical physiology, Ganong’s belongs on your desk. NEW to this edition: Section introductions that provide a foundation for the topic being discussed Two types of review questions: end-of-chapter and board-style Increased number of clinical cases and flow charts • Expanded legends to help you learn more about the illustrations without having to refer back to the text

In 2006, nephrologists in Denmark unexpectedly identified chronic kidney disease (CKD) patients with a new syndrome, nephrogenic systemic fibrosis (NSF). Subsequently, 1603 NSF patients were reported to the Food and Drug Administration. Sixty hospitals in the USA account for 93% of these cases, and two hospitals in Denmark account for 4% of these reports. We review Denmark's identification and subsequent rapid eradication of NSF. METHODS.: NSF reports from clinicians, the Danish Medicines Agency (DMA) and gadolinium-based contrast agents (GBCAs) manufacturers were reviewed (2002-11). RESULTS.: In 1994, the DMA approved a non-ionic linear GBCA, gadodiamide (0.1 mmol/kg), for magnetic resonance imagings (MRIs), with a renal insufficiency contraindication. In 1996, 0.3 mmol/kg dosing received DMA approval. In 1998, the DMA removed renal contraindications. In 1997 and 2002, radiologists at Skejby Hospital and Herlev Hospital, respectively, began performing gadodiamide-enhanced magnetic resonance angiography scans (0.3 mmol/kg) of CKD patients. In 2005, Herlev clinicians requested assistance in evaluating etiological causes of NSF occurring among 10 CKD patients who had developed NSF. This investigation, focusing on infectious agents, was inconclusive. In 2006, Herlev clinicians reported that of 108 CKD patients who had received gadodiamide-enhanced MRI, 20 had developed probable NSF. Herlev radiologists voluntarily discontinued administering gadodiamide to all patients and no new NSF cases at Herlev Hospital developed subsequently. After meeting with Herlev radiologists, Skejby radiologists also discontinued administering gadodiamide to all patients. In 2007, the European Medicines Agency and the DMA contraindicated gadodiamide administration to CKD patients. In 2008, in response to these advisories, radiologists at the other 36 Danish hospitals discontinued administering gadodiamide to all patients, following on practices adopted at Skejby and Herlev Hospitals. In 2009, clinicians at Skejby Hospital reported that a look-back survey identified 33 CKD patients with NSF developing after undergoing GBCA-enhanced MRIs between 1999 and 2007. In 2010, an independent review, commissioned by the Minister of Health, concluded that the DMA had erred in rescinding gadodiamide's renal insufficiency contraindication in 1998 and that this error was a key factor in the development of NSF in Denmark. In 2011, three NSF cases associated with macrocyclic GBCA-associated NSF and three NSF patients with Stages 3 and 4 CKD disease from Skejby Hospital were reported. CONCLUSION.: A confluence of factors led to the development and eradication of NSF in Denmark.

Kenya’s agricultural sector accounts for 20–30% of the gross domestic product (GDP). Of this, the livestock sector alone makes a contribution of about 50%. Thus, livestock contributes heavily to the GDP and food security of its population. It also provides the necessary thrust for other forms of development in the country. Recent statistics indicate that currently over 50% of the country’s livestock population is based in the arid and semi-arid lands (ASALs), which form about 80% of the country’s land area. However, comparative international statistics show that livestock contributes 88% of the total agricultural output in Botswana even though the country has half Kenya’s livestock population and is of less agricultural potential. Thus, there is a huge potential contribution that livestock can make to the Kenyan national economy. Unfortunately, this sector receives only 10% of the government’s agricultural expenditure and less than one per cent of total spending, yet it is estimated that Kenya’s potential to export livestock products if adequately exploited would earn more than the earnings from tea and coffee combined. This then calls for new thinking about livestock development strategies to harness the arid landsThe livestock sector accounts for 90% of employment and more than 95% of household incomes in the ASALs. Most of the livestock slaughtered in major urban centres originates in these areas, with an annual slaughter of about 1.6 million Tropical Livestock Units. Kenya’s livestock from the ASALs is worth Kshs 60 billion (US$800 million). The internal livestock trade in trade in thepastoral areas alone nets in about 6 billion shillings (US$80 million )a yearIn the arid areas of the ASALs, arable crop production is not possible without some form of irrigation; while in semi-arid areas rainfall may be sufficient for certain types of crops, requiring special management techniques. Therefore, except for the areaunder cropping, the rest of the arid areas is used for livestock.......

BACKGROUND: Minimal influenza surveillance has been carried out in sub-Saharan Africa to provide information on circulating influenza subtypes for the purpose of vaccine production and monitoring trends in virus spread and mutations. OBJECTIVE: The aim of this study was to investigate a surveillance program in Kenya to isolate and characterize influenza viruses. RESULTS: In the 2006-2007 influenza season, nine influenza A viruses were isolated. All were of H3N2 subtype with key amino acid (aa) changes indicating that they were more closely related to recent World Health Organization recommended vaccine strains than to older vaccine strains, and mirroring the evolution of circulating influenza A globally. Hemagglutination inhibition data showed that the 2006 Kenya isolates had titers identical to the 2005-2006 H3N2 vaccine strain but two- to threefold lower titers to the 2006-2007 vaccine strain, suggesting that the isolates were antigenic variants of the 2006-2007 vaccine strains. Analysis of aa substitutions of hemagglutinin-1 (HA1) protein of the 2006 Kenyan viruses revealed unique genetic variations with several aa substitutions located at immunodominant epitopes of the HA1 protein. These mutations included the V112I change at site E, the K 173 E substitution at site D and N 278 K change at site C, mutations that may result in conformational change on the HA molecule to expose novel epitopes thus abrogating binding of pre-existing antibodies at these sites. CONCLUSION: Characterization of these important genetic variations in influenza A viruses isolated from Kenya highlights the importance of continuing surveillance and characterization of emerging influenza drift variants in sub-Saharan Africa.

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Nearly three decades into the epidemic, sub-Saharan Africa (SSA) remains the region most heavily affected by human immunodeficiency virus (HIV), with nearly 70% of the 34 million people living with HIV globally residing in the region. In SSA, female and male youth (15 to 24 years) are at a disproportionately high risk of HIV infection compared to adults. As such, there is a need to target HIV prevention strategies to youth and to tailor them to a gender-specific context. This protocol describes the process for the multi-staged approach in the design of the MP3 Youth pilot study, a gender-specific, combination, HIV prevention intervention for youth in Kenya.

Catechol O-methyltransferase (COMT) inactivates neurotransmitters, hormones and drugs such as levodopa. COMT activity is inherited in an autosomal recessive manner and individuals with low activity have thermolabile COMT protein. A low activity allele has been demonstrated at codon 108/158 of the soluble and membrane bound COMT protein, respectively, whereby a G to A transition results in a valine to methionine substitution, rendering the protein more thermolabile. As ethnic differences in erythrocyte COMT activity have been previously demonstrated, the frequency of low activity alleles were investigated in 265 British Caucasian, 99 British South-west Asian and 102 Kenyan individuals. Genotyping of COMT codon 108/158 was performed using a minisequencing method. Erythrocyte COMT activity was measured in 60 British Caucasian individuals by radiochemical assay. The frequency of low activity alleles was 0.54 in Caucasians, 0.49 in South-west Asians, and 0.32 in Kenyans. There was a much lower frequency of individuals with homozygous low activity allele in the Kenyan population (9%) than in Caucasians (31%) or South-west Asians (27%). Erythrocyte COMT activity was lower and less thermostable in individuals with homozygous low activity alleles. The data provide molecular evidence that low COMT is less common in African individuals than the Caucasian population. PMID: 9682265 [PubMed - indexed for MEDLINE]

Genetically determined artemisinin resistance in Plasmodium falciparum has been described in Southeast Asia. The relevance of recently described Kelch 13-propeller mutations for artemisinin resistance in Sub-Saharan Africa parasites is still unknown. Southeast Asia parasites have low genetic diversity compared to Sub-Saharan Africa, where parasites are highly genetically diverse. This study attempted to elucidate whether genetics provides a basis for discovering molecular markers in response to artemisinin drug treatment in P. falciparum in Kenya. The genetic diversity of parasites collected pre- and post- introduction of artemisinin combination therapy (ACT) in western Kenya was determined. A panel of 12 microsatellites and 91 single nucleotide polymorphisms (SNPs) distributed across the P. falciparum genome were genotyped. Parasite clearance rates were obtained for the post-ACT parasites. The 12 microsatellites were highly polymorphic with post-ACT parasites being significantly more diverse compared to pre-ACT (p < 0.0001). The median clearance half-life was 2.55 hours for the post-ACT parasites. Based on SNP analysis, 15 of 90 post-ACT parasites were single-clone infections. Analysis revealed 3 SNPs that might have some causal association with parasite clearance rates. Further, genetic analysis using Bayesian tree revealed parasites with similar clearance phenotypes were more closely genetically related. With further studies, SNPs described here and genetically determined response to artemisinin treatment might be useful in tracking artemisinin resistance in Kenya.

Genetically determined artemisinin resistance in Plasmodium falciparum has been described in Southeast Asia. The relevance of recently described Kelch 13-propeller mutations for artemisinin resistance in Sub-Saharan Africa parasites is still unknown. Southeast Asia parasites have low genetic diversity compared to Sub-Saharan Africa, where parasites are highly genetically diverse. This study attempted to elucidate whether genetics provides a basis for discovering molecular markers in response to artemisinin drug treatment in P. falciparum in Kenya. The genetic diversity of parasites collected pre- and post- introduction of artemisinin combination therapy (ACT) in western Kenya was determined. A panel of 12 microsatellites and 91 single nucleotide polymorphisms (SNPs) distributed across the P. falciparum genome were genotyped. Parasite clearance rates were obtained for the post-ACT parasites. The 12 microsatellites were highly polymorphic with post-ACT parasites being significantly more diverse compared to pre-ACT (p < 0.0001). The median clearance half-life was 2.55 hours for the post-ACT parasites. Based on SNP analysis, 15 of 90 post-ACT parasites were single-clone infections. Analysis revealed 3 SNPs that might have some causal association with parasite clearance rates. Further, genetic analysis using Bayesian tree revealed parasites with similar clearance phenotypes were more closely genetically related. With further studies, SNPs described here and genetically determined response to artemisinin treatment might be useful in tracking artemisinin resistance in Kenya.

The stability of adrenaline ophthalmic solutions, at pH 5.8 and 7.4, to sterilization and storage conditions has been studied. Solutions sterilized by filtration or heating at 98 degrees C for 30 min showed no detectable degradation at either pH value, whilst sterilization at higher temperatures resulted in losses of up to 30%. Total degradation increased with increasing sterilization temperature at both pH values.

Conflict results from a combination of factors, which are intertwined and often deeply rooted in cultural traditions both within and between nations. Poverty is one of the underlying causes of conflict and also one of its consequences. The pastoralists in Isiolo struggle to survive on a fragile ecosystem, which is ravaged by drought, poverty, insecurity and seemingly endless conflict over resources. Given its deleterious effects on development, conflict in Isiolo continues to undermine the underlying resource base for sustainable production systems and the pastoralists' capacity to broaden their livelihoods thereby exacerbating rural poverty. All the actors involved in the Isiolo conflict prevention and resolution and poverty reduction strategies at different levels will underpin their efforts by strengthening governance and helping the local communities to diversify their livelihoods. To be sustainable, the various peace initiatives must be accompanied by a broad range of preventive development strategies, which promote increased access to productive resources by vulnerable groups, recognize the role of women in peace building and encourage peaceful settlement of disputes

Parts one and two of this paper deal with conceptual issues and focus on gender mainstreaming into investment activities for increased women's employment and poverty reduction. The central argument here is that the mainstreaming of a gender perspective into investment activities is necessarily a long-term process which involves the integration of gender issues in all national and sectoral policies and programmes. The key to gender mainstreaming is to make the process a collective responsibility. Some of the essential steps in this process are the production of gender disaggregated data, the establishment and strengthening of gender management systems, the commitment of senior management personnel to the goal of gender equality as a reflection of attitudinal and behaviour change at personal and institutional levels. The discussion in part three brings to the fore the issue of women's education and training. Available data show gender and regional disparities in education and training at primary, secondary and tertiary levels. These data indicate women's limited access to formal education and lower adult literacy rates which undermine their capacity to participate in the formal and informal labour market on an equal basis with men. Part four shows the link between women's education, employment and poverty reduction. The analysis of gender participation in different sectors of the economy revealed some important patterns and trends. These include the fact that female labour force participation in the modern sector has remained below 30% over the last several years compared to men who hold a disproportionately larger share of the modern sector jobs. The majority of women are employed in the education and informal sectors. Those who work in the agricultural sector are usually engaged as casuals. Women's overall lower level of education, limited skills, and access to productive, resources, heavy domestic workload, cultural attitudes and segregation of the labour market are some of the factors associated with their limited participation in the modern sector. Gender representation in the Kenyan civil service also shows gross under-representation of women in top management and policy-making positions. This gender disparity calls for an Affirmative and/or Positive Action to deal not only with increasing women's participation in public and private sector institutions at all levels but also address the twin issue of women's entitlements and cultural barriers which are at the root of their poverty and powerlessness. The low budgetary allocations to women's programmes also reflect lack of political will, improper targeting and non-involvement of women in priority setting.

An integrated geophysical ground survey was conducted on an airborne electromagnetic (EM) anomaly located in Kakamega forest of Western Kenya. The purpose of the study was to establish the existence of massive sulphides and identify suitable optimal geophysical method(s) for the investigation of similar anomalies. The study was also expected to provide information on the geological and geophysical characteristics of the deposit.

Field work involved electromagnetic methods: Vertical Loop (VLEM), Horizontal Loop (HLEM), TURAM EM and potential field methods: gravity and magnetics. Geochemical sampling was carried out concurrently with the geophysical survey.

All the geophysical methods used yielded good responses. Several conductors conforming to the strike of the geology were identified. TURAM EM provided a higher resolution of the conductors compared to VLEM and HLEM. The conductors were found to be associated with positive gravity anomalies supporting the presence of bodies of higher density than the horst rock. Only the western section (west of 625W) of the grid is associated with strong magnetic anomalies. East of 625W strong EM and gravity anomalies persist but magnetic anomalies are weak. This may reflect variation in the mineral composition of the conductors from magnetic to non-magnetic. Geochemical data indicates strong copper anomalies (upto 300 ppm) over sections of the grid and relatively strong zinc (upto 200 ppm) and lead (upto 100 ppm) anomalies. There is a positive correlation between the location of the conductors as predicted by TURAM EM and the copper and zinc anomalies.

A test drill hole proposed on the basis of the geophysical results of this study struck massive sulphides at a depth of 30m still within the weathered rock zone. Unfortunately, the drilling was stopped before the sulphides could be penetrated. The drill core revealed massive sulphide rich in pyrite and pyrrhotite.

An attempt has been made to compare characteristics of the Lirhanda massive sulphide deposit with those of better documented massive sulphides. Despite the fact that very little is known about Lirhanda, there are several similarities on the characteristics compared. These include evidence of back arc regional environment, calc-alkaline volcanic associations, conformity of anomalies to the structural trend of the host rock, proximity of synvolcanic rift, dispersive anomalies of copper and zinc in soils, presence of gossan and association of the deposit with strong EM anomalies.

ABSTRACT

The aeromagnetic survey of the Jombo Hill Area conducted in l977 revealed an anomaly of 2000 gammas in amplitude in the area of the intrusive rocks. This value gtands,out as one of the highest values ever recorded in Kenya. In order to investigate the anomaly further, a gravity survey was conducted in the area within 40 km radius_of Jombo hill. After the necessary corrections to the observed data they were compiled into a Bouguer gravity map of the area.

The Bouguer gravity anomalies range from - 40 to over 50 mgals. The peak of the anomaly occurs immediately to the south of the hill and most of the contours close on this peak. It is noticeable that the magnetic and gravity anomalies are roughly coincident. The relative ease and convenience of gravity 3D modelling relative to magnetic 3D modelling, in the context of this study, dictated the placing of a greater emphasis on the former in the quantitative interpretation.
The gravity anomaly is interpreted in terms of an inverted funnel like body of density 3.1 gcm-3, with its top surface at about l km depth. Estimates from the magnetic map yield a similar value for the depth to the top of the body.

Most of the magnetization in these rocks is the induced type and is in the direction of the ambient field. The large grain size has an appreciable effect on the magnetization in these rocks.
It appears from the study, that both the magnetic and gravity anomalies are caused by a single body. The gravity anomaly depicts the effect of the entire body while the magnetic anomaly that due to a relatively small central and shallow portion of it. The exact geometry of this portion was not determined. However a sphere fitted to the anomaly gave satisfactory results.

By comparison with the geology of the area and with the characteristics of other known alkaline complexes in Eastern Africa, the gravity model is considered geologically reasonable.

ABSTRACT
Anza Graben is situated in the north and northeastern Kenya. It is about 120 km wide and approximately 600 km long. The area of the present study is located mainly in NE Kenya and constitutes a strike length of about 300 km. The graben is almost entirely sediment filled and is estimated to be of Cretaceous age. It is characterized by a prominent negative Bouguer anomaly reaching -40 mGal.

Several studies were made in an effort to determine its subsurface structure. These involved interpretation of a number of seismic reflection profiles, 3D interactive gravity modelling using fixed density contrasts between the sediment infill and the basement, and the analysis by filtering and modelling of the aeromagnetic data hover the graben. A crustal modelling of refraction data along the western shoulder of the Anza graben using 2D ray tracing was also performed.

Two major basins are recognizable from the results of the studies, namely the southern basin which has a northeasterly dip and the northern basin having a southwesterly one. This alternating asymmetry is also indicated for an adjoining smaller basin located to the west of the graben. The density contrast used for the final gravity model is -300 kg/m3 which indicates a maximum sediment thickness of about 8 km. The modelling of aeromagnetic data however favour a maximum thickness of at least 10km. A 2D refraction crustal P wave model of the western shoulder indicates that the crust thins northwestwards with the Moho depth decreasing from 35 km under Chanler's Falls to approximately under the southeastern shores of Lake Turkana. The abrupt shallowing of the Moho in the Lake Turkana area is attributed to the effects of the Kenya Rift Valley. However the gentle variation in the Moho depth along the remaining section of the shoulder of Anza Graben appears to depict a regional phenomenon also attributable to the formation of the Kenya Rift Valley. It is proposed from the study that sections of the graben shoulder are underlain by slightly denser rocks and that the crustal thinning associated with Anza Graben is not significant.

Division of Bacterial and Mycotic Diseases, Centers for Disease Control, Atlanta, GA 30333. An epidemic of meningococcal disease occurred in Nairobi, Kenya, during 1989, outside the "meningitis belt" of sub-Saharan Africa. About 3800 cases occurred between April and November (250/100,000 population). The case-fatality rate was 9.4% among hospitalized patients. Areas that included Nairobi's largest slums had particularly high attack rates. The epidemic displayed an unusual age distribution, with high attack rates among those 20-29 years old. A vaccination campaign was conducted. By early January, the weekly case count had fallen to 25 from a high of 272 (in September). A case-control study estimated the vaccine efficacy to be 87% (95% confidence interval, 67%-95%). A model estimated that the vaccination campaign reduced the number of cases by at least 20%. Multilocus enzyme electrophoretic typing demonstrated that the strain responsible for this large epidemic is closely related to strains that caused other recent epidemics, documenting further spread of what may be a particularly virulent clonal complex of group A Neisseria meningitidis.

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Salmonella typhimurium (ST) can cause infection in man, and attenuated strains are under consideration as live vaccine vectors. However, little is known about the interaction of ST with human dendritic cells (DC). Here, we compared the consequences of exposure of human, monocyte-derived DC with different attenuated strains of ST. Infection was observed with all four strains tested (wild type, PhoP2, PhoPc, and AroA), but the PhoPc strain was by far the most efficient. Intracellular persistence of wild type and PhoP2 was longer than that of PhoPc and AroA, both of which were largely eliminated within 24 h. Most DC survived infection by the attenuated strains, although apoptosis was observed in a fraction of the exposed cells. All strains induced DC maturation, independent from the extent of infection. Although all strains stimulated secretion of TNF-a and IL-12 strongly, PhoPc induced significantly less IL-10 than the other three strains and as much as 10 times less IL-10 than heat-killed PhoPc, suggesting that this mutant suppressed the secretion of IL-10 by the DC. These data indicate that infectivity, bacterial elimination, and cytokine secretion in human DC are controlled by the genetic background of ST. J. Leukoc. Biol. 69: 583–589

This book synthesizes current knowledge of regional-global linkages in four regions to demonstrate that study of environmental change on a regional scale can enhance understanding of global-scale environmental changes. The atmospheric circulation over Southern Africa links regional nutrient and pollutant sources to distant sinks affecting both regional and global ecosystem functioning. Extended human modification of land cover in East Asia has altered the complex surface-atmosphere exchanges impacting the Asian monsoon system. Biogenic and anthropogenic emissions over South Asia are implicated in changes in global tropospheric ozone and oceanic biogeochemical balances. Economic globalisation has negatively impacted regional environments of Southeast Asia.

Keywords » biogeochemical cycling - climate change - environmental change - global change - land use