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This study analysed the profitability of small-scale catfish farming in Kaduna State, Nigeria. Sixty respondents were randomly selected and interviewed using interview schedule to elicit information through multi-stage sampling technique. The data were analysed using frequency, percentages, mean, and ranking while budgetary analysis (gross-margin) was used to determine the profitability of catfish farming. The result shows that majority (70%) used the concrete pond of an average of 200 m2. The source of their capital was mainly from personal savings (48.3%). The quantity of fingerlings raised ranges from 500-6000 at 20 fingerlings/m2. Majority (55%) of the respondents raised between 3000 and 6000 fish per cycle at 6 to 8 tons/ha-1 year-1. Quantity of fish raised and consumed had contributed positively to respondents’ household income. However, savings from catfish farming has contributed about 20 to over 75% of the total income of the respondents. The result of profitability reveals that respondents had an average of about ₦774,223.05 and net gross percentage of 73.4% per production cycle. Inadequate capital, scarcity of fingerlings, and inadequate extension services were the major problems facing catfish farmers. The study recommended that catfish farmers should be encouraged to form and manage functional cooperatives as a way to pool their resources for individual development within the fish farming industry. Also, the government should subsidize the prices of input used in fish farming. Key words: Fish farming, catfish, profitability, Kaduna State.

A large variety of experimental works has been done since the discovery of nuclear fission, aimed at studying different aspects of the phenomenon. Yet our comprehension of the fission process is not complete. This is, among others, due to a certain lack in multi-parameter experimental data. An example here is the correlation between fractional independent yields of fission products and neutron and gamma-ray multiplicities. Fragment-gamma-neutron measurements, especially if correlated with fission- fragment kinetic energies, give the complete set of observables and are therefore of interest from the point of view of modeling and understanding of the fission process. A two-arm spectrometer of fission products (STEFF) has been recently built at the Manchester University. In addition to the identification of masses from complementary fission products, by the double energy/double velocity measurement, the spectrometer is capable of delivering information on their nuclear charges, on the event-by-event basis. The spectrometer also comprises an array of NaI and may house a further array of neutron detectors. In such configuration, STEFF has been used at the ILL neutron guide at the benchmark experiment 235U(nth, f). Details on the experiment will be presented, results on the identification of atomic numbers in the light group of fission products will be demonstrated and the perspectives discussed.

The lifetime of an excited state above a weakly populated isomer in the proton-unbound odd-odd nucleus 144Ho has been measured using the recoil distance Doppler shift method. This measurement represents the first differential-plunger lifetime measurement to utilize recoil-isomer tagging. The first excited I[pi]=(10+) state above the two-quasiparticle [pi]h11/2[circle times operator][nu]h11/2(8+) isomer was determined to have a lifetime of [tau]=6(1)�ps. Potential energy surface calculations, based on the configuration-constrained blocking method, predict the isomeric state to have [gamma]-soft triaxial-nuclear shape with [gamma][approximate]24�. The lifetime of the (10+) state can be understood from these calculations if there is a degree of rotational alignment in this band, with the K value being lower than the bandhead spin. However, the validity of the K quantum number with large predicted triaxiality and gamma softness requires further theoretical study.

The medium-spin structure of the nuclei {sup 93}Rb and {sup 95}Rb is studied following the neutron-induced fission of {sup 235}U at the PF1B neutron guide, using the FIFI spectrometer, and at the Lohengrin mass spectrometer of the Institut Laue-Langevin Grenoble. These nuclei, plus {sup 91}Rb, are also studied following the spontaneous fission of {sup 248}Cm and {sup 252}Cf sources, using the EUROGAM-II and Gammasphere detector arrays, respectively. A high-spin isomeric state, with a half-life of 111(11) ns, is found in {sup 93}Rb at an excitation energy of 4422.4 keV, which most likely corresponds to the fully aligned [{pi}(g{sub 9/2}) x {nu}(g{sub 7/2}h{sub 11/2})]{sub 27/2}{sup -} configuration. An analogous configuration is proposed for the 5297.9-keV level observed in {sup 91}Rb. A new E3 decay branch of the 1133.9-keV isomer in {sup 91}Rb is found, for which the rather low transition rate of B(E3)=3.8(10) W.u. is determined. The energy of the isomeric state of {sup 95}Rb is now proposed to be at 810.6 keV, with a spin of (9/2{sup +}), and its half-life determined to be T{sub 1/2}=94(7) ns. A cascade of prompt transitions is observed on top of the 810.6-keV isomer in {sup 95}Rb. The near-yrast structures of {sup 91}Rb, {supmore » 93}Rb, and {sup 95}Rb are compared to the results of shell-model calculations, which support the proposed 27/2{sup -} interpretation of states in {sup 91}Rb and {sup 93}Rb. An analogous 27/2{sup -} state is expected to occur in {sup 95}Rb, as a long-lived isomer at 3.24 MeV. No such isomeric decay could be observed in a measurement using the Lohengrin spectrometer, which shows that, if it exists, its population, following the fission of {sup 235}U, is at least four times lower than that of the analogous 27/2{sup -} isomer in {sup 97}Y.« less

The known level scheme of {sup 144}Dy has been extended and lifetime measurements have been made with the recoil-distance Doppler-shift method. Reduced transition probabilities and deformations have been determined for four low-lying transitions. These states form part of the first observed band crossing, giving information on the change in nuclear deformation resulting from the rearrangement of h{sub 11/2} protons in the nucleus. Two bands built upon excited 10{sup +} states have been assigned pi(h{sub 11/2}){sup 2} prolate and nu(h{sub 11/2}){sup -2} oblate configurations with tau=12(2)ps and 0.01

International audience; The structure of neutron‐rich nuclei produced as secondary fission fragments was investigated using the EUROGAM and GAMMASPHERE ACS arrays, the LOHENGRIN fission‐fragment mass separator and the FIFI fission‐fragment identifier. Fission products were populated in spontaneous fission of 248Cm and 252Cf and in thermal neutron‐induced fission of 233U, 235U and 241Pu at ILL Grenoble. Particularly useful in such studies are isomeric states, well populated in fission due to their yrast character, easy to detect due to their long half lives and easy to interpret because of their relatively simple composition. We discuss their role in studies of neutron‐rich nuclei, giving examples of isomers found in our recent experiments. A special type of K‐isomers, resulting from 'crossing' of extruder and intruder orbitals plays a role in the mechanism of a sudden onset of deformation in the A = 100 and A = 150 regions. We present evidence for these isomers in both regions. Possible further studies in this field are proposed.

International audience

The medium-spin structure of the neutron-rich, odd-odd nucleus {sup 94}Rb was studied by means of {gamma}-ray spectroscopy. Excited levels were populated in the neutron-induced fission of {sup 235}U and in the spontaneous fission of {sup 252}Cf and {sup 248}Cm. Two isomeric states were found at 1485.2 and 2074.8 keV with half-lives of 18 and 107 ns, respectively. The probable structures of the two isomers involve the fully aligned, proton-neutron configurations [{pi}(g{sub 9/2}) x {nu}(g{sub 7/2})]{sub 8{sup +}} and [{pi}(g{sub 9/2}) x {nu}(h{sub 11/2})]{sub 10{sup -}}, respectively. These new data give information on the single-particle energies in the region.

At present, much effort is being devoted to produce, and to study the properties of, nuclei with high neutron excess. Low-energy fission of very heavy nuclei is one of the best methods to create neutron-rich nuclear matter. The spectrum of products from fission is broad and comprises more than 500 nuclei. A fraction of them produced most abundantly (-100) has been intensively studied with large arrays of y-ray detectors such as Euroball or Gammasphere (see review in Ref. 1 and references therein). The selection of

The amount of energy carried by γ -rays during the fission process is an important consideration when developing new reactor designs. Many studies of γ -ray energy and multiplicity, from a multitude of fissioning systems, were measured during the 1970s. However the data from such experiments largely underestimates the heating effect caused by γ -rays in the structure of a reactor. It is therefore essential to obtain more accurate measurements of the energy carried during γ -ray emission. As such, the OECD Nuclear Energy Agency has put out a high priority request [1] for measurements of the mean γ -ray energy and multiplicity to an accuracy better than 7.5 percent from several fissioning systems; including 235 U(nthermal ). Measurements of the rays from these fissioning nuclei were performed with the SpecTrometer for Exotic Fission Fagments (STEFF).

An ongoing investigation into the angular momentum generated during the fission of 252Cf is currently under way using the SpecTrometer for Exotic Fission Fragments (STEFF). Measurements have been made of the fold distribution (measured multiplicity) with STEFF. These have been compared to a Monte-carlo simulation to determine a value for the average angular momentum Jrms = 6 which is comparable to previous measurements [1]. Measurements of the gamma-ray multiplicity were performed whilst gating on different fragment mass regions. The result was compared with a sum of the lowest 2+ energies from both fragment and complementary in the mass gate. The results support the view that gamma-ray multiplicity is largely determined by the decay of the nucleus through near yrast transitions that follow the statistical decay.

Summary The scarcity and conflicting nature of the existing evidence on the relationship between effective doses of bacterial pyrogens in man and rabbit is pointed out. The dose/quantal response curve for man to a pyrogen prepared from P. vulgaris has been determined and the intravenous ED50 for this preparation is estimated to lie between 0·084 and 0·101 μg./kg. (P = 0·95). The dose/temperature response curves for the rabbit to the same pyrogen preparation, in a variety of different experimental circumstances, have been determined. The relative sensitivities of man and rabbit to this pyrogen have been calculated on a weight-for-weight basis. Taking as the criteria of pyrogenic response (a) a rise of 0·6° C. in the temperature of the rabbit and (b) shivering in man, it is found that the rabbit is one-third to 7 times as sensitive as man, depending on the experimental conditions. 5 The expected efficiencies of the B.P. and U.S.P. tests, in detecting a human ED5 of Pyrogen Test Preparation No. 1 in differing volumes of solution, have been calculated. 6 Some evidence that pyrogens may interact with other substances has been discussed.