Spatial Analysis of Artisanal and Small-Scale Mining in the Tarkwa-Nsuaem Municipality of Ghana

Abstract In recent times there have been lots of public outcry on the environmental and public health and safety effects of Artisanal and Small-scale gold Mining (ASM) and the need to monitor ASM activities for reclamation purposes. To effectively develop and deploy policy responses to the environmental and human health effects of ASM, knowledge of the locations and distribution of ASM sites is a prerequisite. However, information regarding ASM hotspots and spatial distribution, the scope and types of ASM operations are hard to find. Therefore, this research was designed to use satellite-based data to map out ASM sites, focusing on the Tarkwa-Nsuaem municipality as the study area. Several image processing techniques were applied on a Landsat 8 satellite image downloaded from the US Geological Survey website. The image processing resulted in the identification of 221 clusters of ASM sites, representing 12.72% of the total size of the study area. To further explore the effects of these ASM sites, Areas of Interest (AOI) including forest reserve, rivers, large-scale mines and urban settlements were defined. By selecting and analysing the location and distribution of the ASM sites in relations to the AOI, the study was effective in identifying environmentally sensitive and critical areas warranting the urgent attention of society to mitigate the health, safety and ecosystem service effects of ASM in the study area. By identifying the environmental sensitive areas being affected by ASM, the findings could support the prioritisation of reclamation efforts.   Keywords: Artisanal Small-Scale Mining, Satellite Image, Environmental Effect, Public Health and Safet

Modelling of Malaria Risk Areas in Ghana by using Environmental and Anthropogenic Variables – A Spatial Multi- Criteria Approach

Malaria is the leading cause of morbidity and mortality in Ghana, accounting for over three million cases and thousands of deaths annually. The risks of morbidity and mortality associated with malaria are characterized by spatial and temporal variation across the country. This research sought to use GIS and multi-criteria decision analysis to produce a predictive model of malaria using eight risk factors ranging from environmental to anthropogenic. Each of the risk factors was classified into three classes of malaria risk according to how it impacts malaria prevalence. The classified risk factors were finally overlaid through the use of weighted overlay after weights were determined from them using the Analytical Hierarchy Process (AHP). Results indicate that high risk areas are concentrated at the central as well as the west-southern parts of the country consisting mainly of the Ashanti, Brong Ahafo, Eastern, Central and the Western Regions. No area was classified as low risk while 53.51% and 46.49% were classified as medium and high risk respectively. The risk map created can serve not only as a predictive tool, but can be used to obtain a comprehensive understanding of the dynamics of malariatransmission.Keywords: Malaria, GIS, Analytical Hierarchy Process, Weighted Overla

A simple method for the extension of shelf life of cultures of Phytophthora species causing black pod disease of cacao (Theobroma cacao L.)

Black pod disease of cacao caused by Phytophthora palmivora and Phytophthora megakarya in Ghana take heavy toll of cacao production in the field. Intensive research has been carried out worldwide on these pathogens. However, viability of the cultures during prolonged storage has remained a major challenge in the research. This paper reports findings of assessment of six storage media viz sterilised distilled water (SDW), sterilised and unsterilized soil suspension (SSS and USS), vegetable 8 juice broth (V8JB), Oat Meal Agar slant under mineral oil (at 4°C) and empty tube. Viability of the cultures was assessed on V8JA and in tetrazolium chloride test. Ability of zoospores of the cultures to infect cacao leaf discs was used to assess growth vigour and pathogenicity. Phytophthora cultures stored in SDW (26 ± 2°C; alternating day light and night) were preserved for 60 days (5 years). Both P. palmivora and P. megakarya performed better on SDW and SSS than on USS due to removal of staling substances in the soil medium by the sterilisation. Vigour of growth and pathogenicity of the stored cultures required re-inoculation of host tissue (cacao pod) in order to maintain potency to continually infect host

Er3+ doped Silica-on-Silicon using fs-laser doping process for Integrated Waveguide Amplifier Platforms

Rare earth doped waveguide amplifier (EDWA) on silica-on-silicon (SOS) platform are area of great interest for silicon integrated photonics. We report the fabrication of erbium doped silica-on-silicon (SOS) wafer-scale platforms for integrated waveguide amplifier and laser application. We used a method named- ultrafast laser plasma doping (ULPD) process on silica- on-silicon substrates using erbium doped zinc-sodium tellurite glasses (TZN) as targets. The influence of laser energy on the doping process was studied in terms of the refractive index of the waveguides formed and their photoluminescence properties. Planar slab waveguides of refractive index1.64 at 633 nm and characteristic photoluminescence lifetimes of erbium at 1535 nm wavelength emission, varying from 13.38 ms to 10.52 ms were obtained. We used higher repetition rate (10 kHz) amplified Ti-Sapphire laser with pulse duration of 45 fs for faster and efficient growth of active waveguide layer in this research

Aflatoxins and fumonisins contamination of home-made food (Weanimix) from cereal-legume blends for children

Background: Weanimix is an important food for children in Ghana. Mothers are trained to prepare homemade weanimix from beans, groundnuts and  maize for their infants. Groundnuts and maize are prone to aflatoxincontamination while fumonisin contaminates maize. Aflatoxin, is produced by the Asperguillus fungi while fumonisin, is produced by Fusarium fungi. These mycotoxins occur in tropical areas worldwide due to favorable climate for their growth.Objective: The objective of the study was to determine the levels of aflatoxin and fumonisin in homemade weanimix in the Ejura-Sekyedumase district in the Ashanti Region of Ghana.Methods: Thirty six homemade weanimix samples (50g each) were collected from households. Aflatoxin and fumonisin were measured using a fluorometric procedure described by the Association of Official AnalyticalChemist (AOAC official method 993.31, V1 series 4).Results: Aflatoxin and fumonisin were detected in all 36 samples, range 7.9-500ppb. Fumonisin levels range: 0.74-11.0ppm). Thirty (83.3%) of the thirty six samples were over the action limit of 20ppb for aflatoxin withan overall mean of 145.2 ppb whiles 58.3% of the samples had fumonisins above the action limit of 4 ppm with an overall mean of 4.7 ppm .Conclusion: There were significant aflatoxin and fumonisin contamination of homemade weanimix. Children fed on this nutritional food were being exposed to unacceptable levels of aflatoxin and fumonisin. Therefore there is a critical need to educate mothers on the dangers of mycotoxin exposure and to develop strategies to eliminate exposure of children fedhomemade weanimix to aflatoxin and fumonisin.Keywords: Aflatoxin, Fumonisin, Home-made Weanimix, infants

Examination of Combustion-Generated Smoke Particles from Biomass at Source: Relation to Atmospheric Light Absorption

The formation of carbonaceous aerosols from biomass combustion is associated with a high degree of uncertainty in global climate models. In this work, soot samples were generated from the combustion of pine wood, wheat straw and barley straw in a fixed bed stove; as well as from the combustion of biomass pyrolysis model compounds. Samples were collected on filters, which were used for the determination of Absorption Angstrom Exponent (AAE). In addition, the content and composition of elemental carbon (EC) and organic carbon (OC) were determined, and the interrelationships between these and the AAE were examined. It was found that the spectroscopic signature of samples with high ‘brown carbon’ emissions was comparable to that of many PAH and polyphenols, with AAE ranging from 1.0–1.2 for model compounds to 0.5–5.7 for biomass. In addition to the filter samples, particles were collected directly onto microscopy grids and analysed by transmission electron microscopy–electron energy loss spectroscopy (TEM-EELS) in order to determine structural characteristics. This was used to examine the impact of combustion conditions and flue gas dilution on particle structure. Smouldering phase and diluted particles were found to be less graphitic and twice as oxygenated as undiluted flaming phase particles. The results are interpreted to better understand the impact of combustion processes on soot formation from biomass combustion. Abbreviations: AAE: absorption angstrom exponent; ATN: light attenuation; AToFMS: aerosol time of flight mass spectrometer; BC: black carbon; BrC: brown carbon; C:O: carbon to oxygen ratio; CPD: cyclopentadienyl radical C5H5; DMS: differential mobility spectrometer; EC: elemental carbon; EELS: electron energy loss spectroscopy; HACA: hydrogen abstraction carbon addition; MCE: modified combustion efficiency; OA: organic aerosols; OC: organic carbon; PM: particulate matter; POM: primary (particulate)organic matter; Py-GC/MS: pyrolysis gas chromatography/mass spectrometry; sp2: amount of sp2 orbital hybridisation in atomic structure; SSA: single scattering albedo; TC: total carbon (BC+OC) or (EC+OC); TEM: transmission electron microscope; TGA: thermogravimetric analysis

Evaluating Potential Risks of Food Allergy and Toxicity of Soy Leghemoglobin Expressed in \u3ci\u3ePichia pastoris\u3c/i\u3e

Scope: The Soybean (Glycine max) leghemoglobin c2 (LegHb) gene was introduced into Pichia pastoris yeast for sustainable production of a heme-carrying protein, for organoleptic use in plant-based meat. The potential allergenicity and toxicity of LegHb and 17 Pichia host-proteins each representing ≥ 1% of total protein in production batches are evaluated by literature review, bioinformatics sequence comparisons to known allergens or toxins, and in vitro pepsin digestion. Methods and results: Literature searches found no evidence of allergenicity or toxicity for these proteins. There are no significant sequence matches of LegHb to known allergens or toxins. Eleven Pichia proteins have modest identity matches to minor environmental allergens and 13 Pichia proteins have significant matches to proteins from toxic sources. Yet the matched allergens and toxins have similar matches to proteins from the commonly consumed yeast Saccharomyces cerevisiae, without evidence of food allergy or toxicity. The demonstrated history of safe use indicates additional tests for allergenicity and toxicity are not needed. The LegHb and Pichia sp. proteins were rapidly digested by pepsin at pH 2. Conclusion: These results demonstrate that foods containing recombinant soy LegHb produced in Pichia sp. are unlikely to present an unacceptable risk of allergenicity or toxicity to consumers

Phase changeable vanadium dioxide (VO₂) thin films grown from vanadium pentoxide (V₂O₅) using femtosecond pulsed laser deposition

There are significant challenges accompanied by fabricating a pure crystalline VO₂ (M1) thin film with an abrupt metal to insulator phase change properties. Most fabrication methods yield an amorphous VO₂ thin film that requires a post-annealing process to be converted into crystalline VO₂ (M1). Hence, the thickness of VO₂ (M1) films produced is very limited. In this work, we report the growth of pure VO₂ (M1) crystalline thin films onto a sapphire substrate in an oxygen atmosphere by the femtosecond pulsed laser deposition technique and using vanadium pentoxide (V₂O₅) as an ablation target. The thin films were deposited at substrate temperatures of 25 °C, 400 °C, and 600 °C, which reveal the crystallized structures of VO₂ (M1) without post-annealing. The thin film deposited at a substrate temperature of 600 °C exhibits a sharp and an abrupt metal-to-insulator transition (MIT) at a temperature of 66.0 ± 2.5 °C with nearly four orders of magnitude of the resistivity change (3.5 decades) and a narrow MIT hysteresis width of 3.9 °C. Furthermore, the influence of the substrate temperature, nanoparticle or grain size, and film thickness on the MIT parameters such as sharpness of the transition temperature, hysteresis width, and amplitude are discussed for potential applications of tunable antennas, terahertz planar antennas, and RF-microwave switches

Asymptomatic sensitization to a cow\u27s milk protein induces sustained neuroinflammation and behavioral changes with chronic allergen exposure

Mouse models of food allergy have contributed to our understanding of various aspects of the disease, including susceptibilities, symptom spectra, cellular mechanisms, and therapeutic approaches. Previously, we used a mouse model of non-anaphylactic cow’s milk allergy (CMA) and investigated sex- and strain-dependent differences in immunological, neurological, and behavioral sequelae. We showed that male C57BL/6J mice sensitized to a bovine whey protein, β-lactoglobulin (BLG; Bos d 5), exhibited anxiety- and depression-like behavior upon acute allergen challenge. Systemic levels of BLG-specific immunoglobulins, cytokines and chemokines were also elevated in the sensitized mice. Furthermore, neuroinflammation and intestinal dysbiosis were evident as the possible causes of the altered behavior. To assess whether frequent allergen exposure influences CMA-associated pathologies over an extended period in this subclinical model, we placed BLG-sensitized mice on a whey protein (WP)-containing or whey-free control (CTL) diet for 3 months. As expected, allergen-specific IgE was significantly elevated in the plasma after completing the 5-week sensitization phase. However, the IgE levels declined in both diet groups after 3 months. In contrast, allergen-specific IgG1 stayed elevated in sensitized mice with the CTL diet, and the WP diet to a lesser extent. Interestingly, BLG-sensitized mice on the WP diet exhibited anxiety-like behavior and a trend toward spatial memory decline compared to the sham or the sensitized mice on the CTL diet. Moreover, increased immunoreactivities for GFAP and Iba1 and elevated levels of CXCL13 and CCL12, the chemokines involved in central leukocyte recruitment and other neurological diseases, were also observed in the brain. We demonstrated that sensitization to the whey protein, particularly with continuous allergen exposure, resulted in persistent neuroinflammation and associated behavioral changes despite lowered allergen-specific immunoglobulin levels. These results suggested that continuous consumption of the offending allergen may lead to adverse consequences in the brain even after desensitizatio

Health Risk Assessment of Organochlorine Pesticides Contaminations in Dairy Products from Selected Farms in Greater Accra Region-Ghana

The study was geared towards ascertaining the levels of synthetic pyrethroids and organochlorine pesticides residues in dairy products(milk, cheese and yoghurt) from selected farms in Greater Accra Region of Ghana. In all fifty (50) samples of dairy products (25 fresh cow milk, 9 cheese and 16 yoghurt) were analyzed. Detectable levels of organochlorine pesticides,OCPs(β-HCH, endrin, endosulfan, p’p’-DDT, heptachlor and methoxychlor) and Synthetic pyrethroids(permethrin, allethrin, cypermethrin, deltamethrin and cyfluthrin). Ultrasonic extraction was employed and extract clean-up was done using silica gel and analyzed using a gas chromatograph (Agilent Model 6890 Gas Chromatograph) equipped with Ni-63 electron capture detector (ECD). . Milk samples were found to be the most contaminated with respect to the OCPs and the levels ranged between 0.0001μg/ml and 0.0407μg/ml. β-HCH was the highest OCP with concentration of 0.0407μg/ml while Cyfluthrin was the highest synthetic pyrethroids recorded in yoghurt sample (0.0318μg/ml).The levels of organochlorine pesticide residues detected in all the tissues were below the accepted Maximum Residue Limits (MRL), as adopted by the WHO/FAO Codex Alimentarius Commission (2005). Keywords: dairy products, organochlorine pesticides, synthetic pyrethroid, health risk, Ghana, gas chromatograph