Socio-economic processes on Lake Kyoga: potentials for participatory management and poverty eradication

The purpose of this paper is to review selected socio-economic aspects of the Kyoga basin lakes with a view to assessing, the potehtials within the fishing communities for participatory management and poverty eradication. This paper is based on information obtained from three categories of activities. First a review of existing data and reports was undertaken to establish existing knowledge on the subject and identify the gaps.

Identification and characterization of shallow impurity states in gallium arsenide and indium phosphide using photothermal ionization spectroscopy

A model of far infrared (FIR) dielectric response of shallow impurity states in a semiconductor has been developed and is presented for the specific case of the shallow donor transitions in high purity epitaxial GaAs. The model is quite general, however, and should be applicable with slight modification, not only to shallow donors in other materials such as InP, but also to shallow acceptors and excitons. The effects of the enormous dielectric response of shallow donors on the FIR optical properties of reflectance, transmittance, and absorptance, and photoconductive response of high purity epitaxial GaAs films are predicted and compared with experimental photothermal ionization spectra. The model accounts for many of the peculiar features that are frequently observed in these spectra, one of which was the cause of erroneous donor identifications in the early doping experiments. The model also corrects some commonly held misconceptions concerning photo-thermal ionization peak widths and amplitudes and their relationships to donor and acceptor concentrations. These corrections are of particular relevance to the proper interpretation of photothermal ionization spectra in the study of impurity incorporation in high purity epitaxial material. The model also suggests that the technique of FIR reflectance, although it has not been widely employed, should be useful in the study of shallow impurities in semiconductors.

The experimental determination of impact ionization coefficients in gallium arsenide and indium phosphide

U of I Only

Investigating the cosmic-ray ionization rate in the galactic interstellar medium through observations of H3+

Observations of H3+ in the Galactic diffuse interstellar medium (ISM) have led to various surprising results, including the conclusion that the cosmic-ray ionization rate (zeta_2) is about 1 order of magnitude larger than previously thought. The present survey expands the sample of diffuse cloud sight lines with H3+ observations to 50, with detections in 21 of those. Ionization rates inferred from these detections are in the range (1.7+-1.0)x10^-16 s^-1 < zeta_2 < (10.6+-6.8)x10^-16 s^-1 with a mean value of zeta_2=(3.3+-0.4)x10^-16 s^-1. Upper limits (3sigma) derived from non-detections of H3+ are as low as zeta_2 < 0.4x10^-16 s^-1. These low upper-limits, in combination with the wide range of inferred cosmic-ray ionization rates, indicate variations in zeta_2 between different diffuse cloud sight lines. Calculations of the cosmic-ray ionization rate from theoretical cosmic-ray spectra require a large flux of low-energy (MeV) particles to reproduce values inferred from observations. Given the relatively short range of low-energy cosmic rays --- those most efficient at ionization --- the proximity of a cloud to a site of particle acceleration may set its ionization rate. Variations in zeta_2 are thus likely due to variations in the cosmic-ray spectrum at low energies resulting from the effects of particle propagation. To test this theory, H3+ was observed in sight lines passing through diffuse molecular clouds known to be interacting with the supernova remnant IC 443, a probable site of particle acceleration. Where H3+ is detected, ionization rates of zeta_2=(20+-10)x10^-16 s^-1 are inferred, higher than for any other diffuse cloud. These results support both the concept that supernova remnants act as particle accelerators, and the hypothesis that propagation effects are responsible for causing spatial variations in the cosmic-ray spectrum and ionization rate. Future observations of H3+ near other supernova remnants and in sight lines where complementary ionization tracers (OH+, H2O+, H3O+) have been observed will further our understanding of the subject.

Local Field Potentials in the Gustatory Cortex Carry Taste Information

It has been recently shownthat localfield potentials (LFPs)fromthe auditory and visual cortices carry information about sensory stimuli, but whether this is a universal property of sensory cortices remains to be determined. Moreover, little is known about the temporal dynamics of sensory information contained in LFPs following stimulus onset. Here we investigated the time course of the amount of stimulus information in LFPs and spikes from the gustatory cortex of awake rats subjected to tastants and water delivery on the tongue. We found that the phase and amplitude of multiple LFP frequencies carry information about stimuli, which have specific time courses after stimulus delivery. The information carried by LFP phase and amplitude was independent within frequency bands, since the joint information exhibited neither synergy nor redundancy. Tastant information in LFPs was also independent and had a different time course from the information carried by spikes. These findings support the hypothesis that the brain uses different frequency channels to dynamically code for multiple features of a stimulus.

Evaluation and comparison of durability of polycyclic aromatic hydrocarbon compounds (PAHs) and its relation to the lipid content in smoked fishes, Silver carp (Hypophthalmichthys molitrix), Rutilus frisii kutum and Herring (Alosa caspia)

Cold smoking method is one of the commonest ways for fish smoking. It is done by the smoke that is the result of burning hard and soft woods is smoking rooms. Smoke includes a number of chemical constructs and its main part is poly aromatic hydrocarbons. More than one hundred kinds of these constructs are recognized in smoke that is produced from saturated hydrocarbons resulted from the solution of the woods Ligno cellulose in high temperature and lack of oxygen conditions. The high poisoning potentials and carcinogenic features sixteen constructs among them are proved and observed on humans. In this research, the PAH compounds were identified and observed in a three month period after smoking and during storing among three types of smoked fishes Silver carp and Caspian sea Sefid and herring. They are the most produced and consumed smoked fish in Iran. To find the relationship between the concentrations of PAH constructs and the amount of lipid in fish, first, the amount of lipid were determined separately in the skin and flesh of 30 samples of each type. The method used was Bligh and Dyer (1959). PAH compounds derivation were made for all skin and flesh samples smoked fish using organic solvents with Soxeleh and the derived samples were injected to gas chromatography (GC) by Hamilton injectors for determining their components quality and their quantity. The height of the used column was 25 meters and its diameter was 0.32 mm with the silica filler, nitrogen gas as carrier and flame ionization detector (FID) that are special for these constructs. For data analysis, Statistical tests were used by computer soft ware identified that the difference in the amount of lipid within the flesh and skin of each species and also among each other is significant. The largest amount was in Herrings flesh and skin, 18.74% in skin and 14.47% in flesh. The least amount in the skin 4.19% and the flesh 3.10% of Sefid. The amount in Silver carp was 13.28%in skin and 8.16% in flesh. The examination of the PAH compounds in smoked fish showed that is carcinogenic compounds; exist in these in these fish with different quantities in each. It seems that its amount is directly related to the amount of their lipid. The amount is different in flesh and skin. One of the most important reasons is the direct content of smoke and the concentration of lipid in tissues of all three types. The maintenance of the smoked fish for three months showed that most of PAH compounds were solved and their density decreased. The changes in density within time in different in each type and in flesh and skin. The amount of their receiving in human through the consumption of the smoked fish depends on the resulted density, the way and the amount of consumption and now we can determine and execute standards for the maximum dosage per day and per month regarding effective factors.

Geological Characterisation of Depleted Oil and Gas Reservoirs for Carbon Sequestration Potentials in a Field in the Niger Delta, Nigeria

The injectivity, containment and storage capacity of sandstone reservoirs in a field in the Coastal Swamp depobelt of the onshore eastern Niger Delta were evaluated using wireline logs and seismic data to assess their potentials for carbon dioxide storage and geosequestration. The reservoir formation consists of multilayered alternating beds of sandstone and shale cap rocks. Active seismicity and fracturing intensity are low and growth faults provide the reservoir sealing mechanisms. Three reservoirs were delineated at depths between 3319 m and 3539 m which will keep injected CO2 in a supercritical state. The reservoir depth of at least 800 m, porosity and permeability of more than 10 percent and 20 mD, and a caprock thickness of at least 10 m, in addition to geothermal gradients of 13.46 to 33.66 ºC /km are the ideal conditions for the efficacy of storage. Comparison of the derived reservoir and seal properties such as porosity, permeability, thickness and depth with the minimum recommended site selection criteria shows that the reservoirs are potential candidates for carbon geosequestration with a total theoretical storage capacity of 147MM tons.

Anti-nociceptive and anti-inflammatory potentials of fractions from the extract of Tetracarpidium conophorum leaf in rats and mice

Tetracarpidium conophorum (TC) (Euphorbiaceae) is a perennial woody climbing shrub in low bush forest of some parts of West Africa and used among the natives for relief of ailments accompanying pain and inflammation. In this study, the analgesic and anti-inflammatory effects of the methanolic extract (METC) and fractions (ethyl acetate, F1 and n-hexane, F2) of Tetracarpidium conophorum leaf were evaluated in rat and mice. The analgesic activity was evaluated using acetic acid-induced writhing, formalin-induced paw licking and hot plate test models. Carrageenan-induced paw oedema was used to assess anti-inflammatory activity in rats. The mechanism of action of (TC) was explored by the use of naloxone, a non-selective opioid receptor blocker. The highest analgesic effect was observed in F2 extract at 57.21% inhibition and was further studied on various analgesic and anti-inflammatory models in graded doses. F2 significantly inhibited the late phase of formalin-induced paw licking and prolong hot plate latency at 55±1°C. The n-hexane fraction also significantly inhibited carrageenan-induced paw oedema in rats at 100 and 200mg/kg doses significantly (p< 0.001) and reduced paw licking response by 85.08% compared with control. Naloxone, an opioid receptor antagonist, did not significantly affect the changes observed with n-hexane fraction, thus ruling out the possibility of the involvement of opioid receptors in the analgesic actions of Tetracarpidium conophorum. Phytochemical screening showed that the leaf extracts contain alkaloids, tannins, saponins and cardenolides. The investigations showed that Tetracarpidium conophorum possesses significant anti-nociceptive and anti-inflammatory activities that should be explored.

Conceptual Reference Model for Virtual Factory: Potentials for Collaborative Business

Part 11: Reference and Conceptual Models