Cup anemometer response to the wind turbulence-measurement of the horizontal wind variance

International audienceThis paper presents some dynamic characteristics of an opto-electronic cup anemometer model in relation to its response to the wind turbulence. It is based on experimental data of the natural wind turbulence measured both by an ultrasonic anemometer and two samples of the mentioned cup anemometer. The distance constants of the latter devices measured in a wind tunnel are in good agreement with those determined by the spectral analysis method proposed in this study. In addition, the study shows that the linear compensation of the cup anemometer response, beyond the cutoff frequency, is limited to a given frequency, characteristic of the device. Beyond this frequency, the compensation effectiveness relies mainly on the wind characteristics, particularly the direction variability and the horizontal turbulence intensity. Finally, this study demonstrates the potential of fast cup anemometers to measure some turbulence parameters (like wind variance) with errors of the magnitude as those deriving from the mean speed measurements. This result proves that fast cup anemometers can be used to assess some turbulence parameters, especially for long-term measurements in severe climate conditions (icing, snowing or sandy storm weathers)

Impact of Competition on the Financial Performance of Listed Deposit Money Banks in Nigeria

The impact of bank competition on bank performance remains a widely debated issue. At present, scholars investigate either the competition-stability or the competition-fragility relationships. The traditional competition-fragility view equates bank competition with instability as competition reduces market power and profit margins which in turn encourages bank managers to take higher risks. In contrast, the competition-stability view stipulates that competition leads to lower loan interest rates and consequently lower moral hazard and adverse selection problems and less risky loan portfolios. This study examines both paradigms using panel data from deposit money banks in Nigeria over a period of ten years (2005-2014). Results show that the overall relationship between competition and financial performance of banks is negative. The study, therefore, concludes that competition has a negative effect on the financial performance of banks in Nigeria. The study suggests that regulators should promote healthy competition among deposit money banks so as to reduce the negative effect of competition on bank financial performance. Managers should take measures to enhance profit margin by reducing expenses. Current efforts of the government in terms of improved power generation may help to cut cost of power borne by the banks. Managers should also ensure healthy loan portfolio by ensuring that only customers with high credit scores get loans. Keywords: Bank, competition, financial performance, loan, market share, Nigeria, profit margin, risk.

Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

International audienceThis paper deals with the characteristics of turbulent flow over two agricultural plots with various tillage treatments in a fallow, semiarid area (Central Aragon, Spain). The main dynamic characteristics of the Atmospheric Surface Layer (ASL) measured over the experimental site (friction velocity, roughness length, etc.), and energy budget, have been presented previously (Frangi and Richard, 2000). The current study is based on experimental measurements performed with cup anemometers located in the vicinity of the ground at 5 different levels (from 0.25 to 4 m) and sampled at 1 Hz. It reveals that the horizontal wind variance, the Eulerian integral scales, the frequency range of turbulence and the turbulent kinetic energy dissipation rate are affected by the surface roughness. In the vicinity of the ground surface, the horizontal wind variance logarithmically increases with height, directly in relation to the friction velocity and the roughness length scale. It was found that the time integral scale (and subsequently the length integral scale) increased with the surface roughness and decreased with the anemometer height. These variations imply some shifts in the meteorological spectral gap and some variations of the spectral peak length scale. The turbulent energy dissipation rate, affected by the soil roughness, shows a z-less stratification behaviour under stable conditions. In addition to the characterization of the studied ASL, this paper intends to show which turbulence characteristics, and under what conditions, are accessible through the cup anemometer

Prevalence of plant-parasitic nematodes associated with tomatoes in three agro-ecological zones of Ghana

A study was conducted between August 2014 and May 2015 to identify plant-parasitic nematodes taxa associated with tomato (Solanum lycopersicum L.) and to assess the knowledge, perceptions and experiences of growers of the crop on occurrence and management of the parasites on their farms in nine communities within the semi-deciduous forest, the forest/savanna transitional and the savanna agro-ecological zones of Ghana. Semi-structured questionnaires were designed and administered to 54 randomly selected growers from the nine communities. Composite rhizosphere soil and tomato root samples were collected from two farms in each of the nine communities, and nematodes extracted, identified and recorded. The study revealed that many growers (73%) could not distinguish between nematode infestation, nutrient deficiency and moisture stress and, therefore, lacked knowledge on nematode control. Most of the growers (63%) continually cropped their land to tomato for periods of 4 –7 years without fallowing. All growers applied only inorganic fertilizer to their crops. Symptoms of nematode infestation were widespread in fields with high yield losses. Tomato was a host to Helicotylenchus spp. (11.5% in soil), Hoplolaimus spp. (1.0 % in soil), Meloidogyne spp. (37.4% in soil and 69.3% in roots), Pratylenchus spp. (20.6% in soil and 13.7% in roots), Rotylenchulus spp. (11.0% in soil and 12.2% in roots), Scutellonema spp. (9.5% in soil and 4.9% in roots), Tylenchus spp.(7.6% in soil) and Xiphinema spp.(1.4% in soil) across the nine communities surveyed. Semi-deciduous forest and Savanna agro-ecological zones had the highest and least population densities of nematodes, respectively. These nematodes, if not managed efficiently, could also serve as constraint to tomato production in the country

Fatigue Behaviour of Medium Carbon Steel of Different Grain Structures

This paper investigated the effect of heat treatment operations on the fatigue resistance of low carbon steel. Specimens after preparation for fatigue testing were subjected to annealing, normalizing and quenching heat treatment. Results show that the annealed specimen had the largest number of cycles to failure, indicating a high fatigue resistance. The microstructure of the specimens was examined in other to corroborate the obtained property with the microstructure. When compared with the untreated specimen, the annealed specimen (with optimum fatigue resistance) shows a large grains size of pearlite which was distributed across the entire surface of the microstructure. Generally, it was found that the size and distribution of specimens’ grains affect the resistance of the low carbon steel to fatigue failure. Keywords: fatigue, low carbon steel, heat treatment, microstructur

Detection and isolation of chikungunya virus from field collected Aedes albopictus skuse in selected sites, Peninsular Malaysia

Chikungunya fever, an Aedes borne viral disease, is becoming a serious public health concern today since the first reported outbreak in Port Klang in 1998/99. Recently, more outbreaks were reported in Malaysia. Entomological investigations were conducted in Chikungunya virus cases localities in Peninsular Malaysia which cover Johor, Negeri Sembilan, Melaka, Perak, Pahang and Selangor state in order to identify the vector responsible for transmitting the Chikungunya virus. The adult mosquitoes were collected using modified aspirator and sweep net methods, whereas water holding containers were inspected for larvae. Reverse transcriptase polymerase chain reaction (RT-PCR) were used as the detection of the virus. Positive samples were inoculated on the cell to isolate the virus. The most common species collected at the localities was Aedes albopictus followed by Culex quinquefasciatus, Aedes aegypti and Armigeres sp. Five pools (n=78) of female, adult Aedes albopictus collected from Tangkak, Johor were positive for the Chikungunya virus as detected by reverse transcription-polymerase chain reaction. Three isolates were obtained and grouped with Central/East African genotype. The presence of Chikungunya virus in wild Aedes albopictus indicated that this mosquito is the most likely vector responsible for the transmission of virus to humans in Johor during the outbreak

Current status of infectious diseases among migrants and non-citizens in Malaysia

The mass movement of migrants to Malaysia for employment is one of the factors contributing to the emergence and re-emergence of infectious diseases in this country. Despite mandatory health screening for migrants seeking employment, prevalence records of infectious diseases amongst migrant populations in Malaysia are still within negligible proportions. Therefore, the present review highlights the incidence, mortality and overall status of infectious diseases amongst migrants’ populations in Malaysia, which maybe be useful for impeding exacerbation of inequalities among them and improving our national health system thru robust and effective emergency responses in controlling the prevalent diseases found among these populations and maybe, Malaysian citizens too. Peer-reviewed articles from January 2016 to December 2020 were searched through online platform including SCOPUS, PubMed, Science Direct, and Google Scholar. Non-peer-reviewed reports and publications from ministry and government websites including data from related agencies were also scoured from in order to ensure that there are no cases being overlooked, as most published articles did not have migrants as the research subjects. A total of 29 studies had been selected in the final analysis. Migrants in Malaysia were at higher risk for tuberculosis, malaria, lymphatic filariasis, cholera, leprosy and leptospirosis. Lymphatic filariasis was still endemic among this population while thousand cases of TB and cholera had been reported among them due to cramp living conditions and poor sanitation in their settlements respectively. While malaria had gradually decreased and become sporadic, the influx of migrant workers had led to the rising of imported malaria cases. Low cases of leprosy had been recorded in Malaysia but a significant proportion of it was contributed by migrant workers. As for leptospirosis, studies found that there are prominent cases among migrant workers, which particularly highest within workers with lower educational attainment. Infectious diseases are still prevalent among migrants in Malaysia due to various interplay factors including their working sectors, country of origin, immunization status, type of settlement, impoverished living conditions, and language and cultural barriers that impeding access to health facilities.</p

Racial residential segregation and colorectal cancer mortality in the Mississippi Delta Region

INTRODUCTION: Few studies have examined the effects of racial segregation on colorectal cancer (CRC) outcomes, and none has determined whether rurality moderates the effect of racial segregation on CRC mortality. We examined whether the effect of segregation on CRC mortality varied by rurality in the Mississippi Delta Region, an economically distressed and historically segregated region of the United States. METHODS: We used data from the US Census Bureau and the 1999-2018 Surveillance, Epidemiology, and End Results (SEER) program to estimate mixed linear regression models in which CRC mortality rates among Black and White residents in Delta Region counties (N = 252) were stratified by rurality and regressed on White-Black residential segregation indices and 4 socioeconomic control variables. RESULTS: Among Black residents, CRC mortality rates in urban counties were a function of a squared segregation term (b = 162.78, P = .01), indicating that the relationship between segregation and CRC mortality was U-shaped. Among White residents, main effects of annual household income (b = 29.01, P = .04) and educational attainment (b = 34.58, P = .03) were associated with CRC mortality rates in urban counties, whereas only annual household income (b = 19.44, P = .04) was associated with CRC mortality rates in rural counties. Racial segregation was not associated with CRC mortality rates among White residents. CONCLUSION: Our county-level analysis suggests that health outcomes related to racial segregation vary by racial, contextual, and community factors. Segregated rural Black communities may feature stronger social bonds among residents than urban communities, thus increasing interpersonal support for cancer prevention and control. Future research should explore the effect of individual-level factors on colorectal cancer mortality