Determinants of adoption level of risk management strategies by fish farmers in Degema Local Government Area of Rivers State, Nigeria

The study examined the socio-economic determinants of level of adoption of risk management strategies by fish farmers in Degema Local Government Area of Rivers State. The study specifically described the socioeconomic characteristics of fish farmers, identified the various sources of risk and determined the socioeconomic factors that influence the level of adoption of risk management strategies. A two-stage sampling technique was used to select sixty-seven (67) fish farmers. Structured questionnaire and interview schedule were used for data collection. Data analysis was done using descriptive statistics and multiple regression. The result showed that majority were young male with an average age of 40 years. The most common sources of risk were the fluctuation in prices of fish feed and fish. The age of farmers, household size, and farming experience were some of the factors that influenced the adoption to risk management strategies. However due to the inadequate extension service activities, farmers were not able to fully utilize the different and essential risk management strategies. Hence, the study recommends that young women should be encouraged to invest in fish farming business. Also, extension agents should be encouraged to disseminate useful information to farmers on essential risk management strategies.Keywords: Risk, Risk Management Strategies, Fish farming, Adoptio

Automatic General of a Neural Network Architecture Using Evolutionary Computation

This paper reports the application of evolutionary computation in the automatic generation of a neural network architecture. It is a usual practice to use trial and error to find a suitable neural network architecture. This is not only time consuming but may not generate an optimal solution for a given problem. The use of evolutionary computation is a step towards automation in architecture generation. In this paper a brief introduction to the field is given as well as an implementation of automatic neural network generation using genetic programmin

A molecular phylogeny of Southeast Asian Cyrtandra (Gesneriaceae) supports an emerging paradigm for Malesian plant biogeography

The islands of Southeast Asia comprise one of the most geologically and biogeographically complex areas in the world and are a centre of exceptional floristic diversity, harbouring 45,000 species of flowering plants. Cyrtandra, with over 800 species of herbs and shrubs, is the largest genus in the family Gesneriaceae and is one of the most emblematic and species-rich genera of the Malesian rainforest understorey. The high number of species and tendency to narrow endemism make Cyrtandra an ideal genus for examining biogeographic patterns. We sampled 128 Cyrtandra taxa from key localities across Southeast Asia to evaluate the geo-temporal patterns and evolutionary dynamics of this clade. One nuclear and four chloroplast regions were used for phylogenetic reconstruction, molecular dating, and ancestral range estimation. Results from the dating analysis suggest that the great diversity of Cyrtandra seen in the Malesian region results from a recent radiation, with most speciation taking place in the last five million years. Borneo was recovered as the most likely ancestral range of the genus, with the current distribution of species resulting from a west to east migration across Malesia that corresponds with island emergence and mountain building. Lastly, our investigation into the biogeographic history of the genus indicates high levels of floristic exchange between the islands on the Sunda shelf and the important role of the Philippines as a stepping stone to Wallacea and New Guinea. These patterns underlie much of the plant diversity in the region and form an emerging paradigm in Southeast Asian plant biogeography

Magnetooptical effects in quantum wells irradiated with light pulses

The method of detection and investigation of the magnetopolaron effect in the semiconductor quantum wells (QW) in a strong magnetic field, based on pulse light irradiation and measuring the reflected and transmitted pulses, has been proposed. It has been shown that a beating amplitude on the frequencies, corresponding to the magnetopolaron energy level splitting, depends strongly from the exciting pulse width. The existence of the time points of the total reflection and total transparency has been predicted. The high orders of the perturbation theory on electron-electromagnetic field interaction have been taken into account.Comment: 5 pages, 5 figures with captions, corrected typos, figures are reedeted to improve their quality in accordance with the Referee requirement; Phys. Rev. B, Brief Reports, submitted for publicatio

An Improved Description of the Dielectric Breakdown in Oxides Based on a Generalized Weibull distribution

In this work, we address modal parameter fluctuations in statistical distributions describing charge-to-breakdown $(Q_{BD})$ and/or time-to-breakdown $(t_{BD})$ during the dielectric breakdown regime of ultra-thin oxides, which are of high interest for the advancement of electronic technology. We reobtain a generalized Weibull distribution ($q$-Weibull), which properly describes $(t_{BD})$ data when oxide thickness fluctuations are present, in order to improve reliability assessment of ultra-thin oxides by time-to-breakdown $(t_{BD})$ extrapolation and area scaling. The incorporation of fluctuations allows a physical interpretation of the $q$-Weibull distribution in connection with the Tsallis statistics. In support to our results, we analyze $t_{BD}$ data of SiO$_2$-based MOS devices obtained experimentally and theoretically through a percolation model, demonstrating an advantageous description of the dielectric breakdown by the $q$-Weibull distribution.Comment: 5 pages, 3 figure

Plasma formation from ultracold Rydberg gases

Recent experiments have demonstrated the spontaneous evolution of a gas of ultracold Rydberg atoms into an expanding ultracold plasma, as well as the reverse process of plasma recombination into highly excited atomic states. Treating the evolution of the plasma on the basis of kinetic equations, while ionization/excitation and recombination are incorporated using rate equations, we have investigated theoretically the Rydberg-to-plasma transition. Including the influence of spatial correlations on the plasma dynamics in an approximate way we find that ionic correlations change the results only quantitatively but not qualitatively

The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). III. The Mass Function of Young Star Clusters in M33

We measure the star cluster mass function for the Local Group galaxy M33. We use the catalog of stellar clusters selected from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. We analyze 711 clusters in M33 with $\rm 7.0$ 3.0 as determined from color-magnitude diagram fits to individual stars. The M33 cluster mass function is best described by a Schechter function with power law slope $\alpha = -2.06^{+0.14}_{-0.13}$, and truncation mass log($M_c/M_{\odot}$) $= 4.24^{+0.16}_{-0.13}$. The data show strong evidence for a high-mass truncation, thus strongly favoring a Schechter function fit over a pure power law. M33's truncation mass is consistent with the previously identified linear trend between $M_c$, and star formation rate surface density, \SigSFR. We also explore the effect that individual cluster mass uncertainties have on derived mass function parameters, and find evidence to suggest that large cluster mass uncertainties have the potential to bias the truncation mass of fitted mass functions on the one sigma level.Comment: 18 pages, 15 figures, 1 table, Accepted to ApJ (February 2, 2022

Engaging Long-Term Care Workers in Research: Recruitment Approaches and Participant Characteristics From a Randomized Controlled Trial to Improve COVID-19 Vaccine Confidence.

To describe and compare the recruitment methods employed in a randomized controlled trial targeting long-term care workers, and resulting participant baseline characteristics. We used a multifaceted recruitment process to enroll long-term care workers in our 3-arm randomized controlled trial comparing 2 interventions to enhanced usual practice, for improving COVID-19 vaccine confidence and other outcomes. Adult long-term care workers living in the United States employed within the last 2 years were invited to join the study. Participants also had to meet specific screening criteria related to their degree of worry about the vaccine and/or their vaccination status. We used a participatory approach to engage our long-term care stakeholders in codesigning and executing a combination of recruitment methods, including targeted e-recruitment, paid e-recruitment, and in-person recruitment. Participants were screened, consented, and enrolled online. We implemented a participant verification process to ensure the integrity of our study data, and used a tailored participant management platform to manage enrollment. We enrolled 1930 long-term care workers between May 2022 and January 2023. We met our enrollment target, despite each recruitment method having limitations. Total variable costs of approximately $102,700 were incurred and differed on a per-enrolled participant basis across methods:$25.73 for targeted e-recruitment, $57.12 for paid e-recruitment, and$64.92 for in-person methods. Our sample differed from the national population in age, gender, race/ethnicity, education, and role in long-term care. Differences were also observed between online and in-person recruitment methods. Our results support the feasibility of enrolling a large number of long-term care workers in a randomized controlled trial to increase COVID-19 vaccine confidence. Findings build upon the evidence base for engaging this important population in research, a critical step to improving long-term care resident health and well-being. Results from our trial are anticipated in 2024