Determination of relative contribution of different meteorological elements on evaporation

The present study deals with influence of radiation, maximum temperature, hours of bright sunshine, relative humidity and surface wind on evaporation at Calcutta, Pune and New Delhi. Daily data from 1991-94 of January, May, June, July and October have been utilized. Direct and indirect influence of the weather factors have been determined through "path analysis" and discussed. Multiple regression equations have also been developed with evaporation as the dependent variable and the above five weather parameters as independent variables. The results reveal that radiation and maximum temperature are the two most important parameters which enhance evaporation. Most of their effect is direct though in some cases their interaction with relative humidity or wind also contribute significantly to evaporation. Humidity and surface wind, generally, do not significantly contribute directly to evaporation; their effect is manifested through interaction with maximum temperature, indirectly.

Amblyomma mixtum free-living stages: Summer and winter use, preference, and niche width in an agroecosystem (Yopal, Casanare, Colombia)

Studying a species’ tolerance to an ecosystem’s environmental conditions and its selection of available resources is relevant in ecological and evolutionary terms. Moreover, formulation of effective control strategies implicitly includes the study of habitat use and preference and niche width in anthropogenically transformed natural landscapes. Here, we evaluated whether the use, habitat preference, and niche range of the Amblyomma mixtum tick changed between stages, habitats, and seasons (summer-winter 2019) on a farm in Yopal (Casanare, Colombia). To this end, the presence and relative abundance of larvae, nymphs, and free-living adults was quantified in four different habitats according to the type of vegetation cover (Riparian Forest, Cocoa Crop, King Grass Crop, and Star Grass Paddock). Habitat availability was calculated, environmental variables were analyzed, and various indices of habitat use and preference and niche width were calculated. A. mixtum’s habitat use and preference and niche width changed between stages, habitat types, and time of the year. The total abundance of A. mixtum was an order of magnitude greater in summer than winter. Nymphs and larvae dominated it in the summer and adults in the winter. In summer, all the stages used the four habitats. In winter, the larvae did not use two habitats (Riparian Forest and Cocoa Crop); nymphs did not use the cocoa crop. A. mixtum adults used all the habitats in both seasons. In summer, the nymphs and larvae preferred three of the four habitats (King Grass Crop, Star Grass Paddock, and Cocoa Crops), while adults preferred the King Grass Crop. In winter, the nymphs and larvae preferred the King Grass Crop and Star Grass Paddock, while the adults preferred the King Grass Crop. The value of the niche width index was high for larvae, nymphs, and adults in summer, while it was high only for adults in winter. A. mixtum is exposed to significant daily, seasonal, and multiannual variations in relative humidity (minimum 30%), ambient temperature (minimum 18°C), solar radiation (maximum 800 W/m2), and precipitation (maximum 481 mm/month). Thus, the local A. mixtum population could rapidly acclimatize to changing habitats (unstable or temporary) under fluctuating environmental conditions (e.g., King Grass Crop). However, the winter flood season in Yopal could exceed A. mixtum’s adaptive capacity during its most vulnerable stages. Mathematically, a low number of female A. mixtum, surviving the most demanding environmental conditions, could sufficiently ensure the population’s persistence, which, coupled with the vast host range, could facilitate the ticks stages’ dispersal among habitats to complete their life cycle. A. mixtum’s population control should be carried out during its season of greater vulnerability (winter), when the population is low, particularly the females.

NOx AND O3 VARIABILITY AND ITS RELATION WITH WEATHER CONDITIONS IN IAȘI CITY

The paper presents the temporal variability of surface ozone (O3) and its precursors (oxides of nitrogen - NOx) from January 2012 to December 2015. In the same time, this study is aimed to explore the influence of the weather elements on these two major atmospheric pollutants in the area of Iași city. The maximum record of nitrogen oxides reached during the 4 analyzed years was 1200 μ/m-3 on October 27, 2015, a period of the year when atmospheric stability prevails. During the warm season (considered from May to September) the highest concentration of ozone was recorded at 155 μ/m-3. The winds direction from SSE or NNW and the winds speed greater than 2 m/s can significantly increase the concentration of the O3 and NOx respectively. Also, the stable atmospheric conditions can increase especially the concentration of the nitrogen dioxides. The statistical results illustrate a strong Pearson's correlation of surface ozone with solar radiation/maximum air temperature (r >0.5). The correlations were strongest during the summer months. Using the composite method, between warm season and cold season a difference of the pollutants concentration greater than 30 units for NOx was observed. Synoptic conditions associated with high pollution are also described.

Empirical models for predicting global solar radiation using meteorological parameters for Sokoto, Nigeria

The performances of sunshine, temperature and multivariate models for the estimation of global solar radiation for Sokoto (Latitude 13.020N, Longitude 05.250E and 350.8 m asl) located in the Sahelian region in Nigeria were evaluated using measured monthly average daily global solar radiation, maximum and minimum temperatures, sunshine hours, rainfall, wind speed, cloud cover and relative humidity meteorological data during the period of thirty one years (1980-2010). The comparison assessment of the models was carried out using statistical indices of coefficient of determination (R2), Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t – test, Nash – Sutcliffe Equation (NSE) and Index of Agreement (IA). For the sunshine based models, a total of ten (10) models were developed, nine (9) existing and one author’s sunshine based model. For the temperature based models, a total of four (4) models were developed, three (3) existing and one author’s temperature based model. The results of the existing and newly developed author’s sunshine and temperature based models were compared and the best empirical model was identified and recommended. The results indicated that the author’s quadratic sunshine based model involving the latitude and the exponent temperature based models are found more suitable for global solar radiation estimation in Sokoto. The evaluated existing Ångström type sunshine based model for the location was compared with those available in literature from other studies and was found more suitable for estimating global solar radiation. Comparing the most suitable sunshine and temperature based models revealed that the temperature based models is more appropriate in the location. The developed multivariate regression models are found suitable as evaluation depends on the available combination of the meteorological parameters based on two to six variable correlations. The recommended models are found suitable for estimating global solar radiation in Sokoto and regions with similar climatic information with higher accuracy and climatic variability.

Influence of spunbond degradable floating row covers on microclimate modification and yield of field cucumber

In recent years, there has been an increase in interest in innovative plastic materials for use in horticulture. The aim of this study was to examine the effects of (bio)degradable floating covers (polylactide nonwoven ‒ PLA, and oxo-degradable polypropylene nonwoven with 0.1% iron stearate ‒ PP photo, both 20 g/m2) compared to the conventional PP nonwoven (control, 20 g/m2) on microclimate modification and yield of field-grown cucumber. The greatest PAR transmittance was recorded for the control nonwoven (83%), while the degradable materials transmitted 8% less radiation. Maximum soil surface temperatures were the highest under the PLA nonwoven, but minimum temperatures ‒ under the oxo-degradable fleece. The mean temperature under the oxo-degradable material was comparable to the control, while PLA increased the soil temperature by 1.8 °C, on average. The yield from cucumber plants covered with degradable materials was similar to that from the plants cultivated under the conventional oil-based nonwoven fleece. There were no significant changes in dry weight and soluble sugar content in cucumber fruits in 2013; however, the degradable nonwovens decreased these parameters in 2012. The lifespan of the oxo-degradable nonwoven was limited only to one growing season, thus the durability of the polymer must be increased. Polylactide nonwoven can be a sustainable ecological alternative to conventional non-degradable PP covers.

Protected Fresh Grapefruit Cultivation Systems: Antipsyllid Screen Effects on Environmental Variables inside Enclosures

Huanglongbing (HLB) disease is a threat to most citrus (Citrus sp.) producing areas and is associated with the bacterium Candidatus Liberibacter asiaticus. The disease is transmitted by the vector asian citrus psyllid [ACP (Diaphoria citri)]. Antipsyllid screen houses can potentially reduce and eliminate HLB development in young citrus plantings by excluding the insect vector. These structures are also anticipated to represent a new environmental platform to cultivate high-valued fresh citrus. The purpose of this investigation was to evaluate the effect of screen houses on excluding infective ACP from inoculating grapefruit (Citrus ×paradisi) trees and determine changes on environmental conditions caused by the screen cloth. We tested two coverings [enclosed screen house and open-air (control)] and two planting systems (in-ground and container-grown), with four replications arranged in a split-plot experimental design. Psyllid counting and HLB diagnosis were performed monthly, and the antipsyllid screen excluded the HLB vector from the houses. ACP and HLB-positive trees were found only at the open-air plots. Weather monitoring was performed every 30 minutes from 22 Feb. to 31 July 2014. Solar radiation accumulation averaged 6.7 W·m−2·minute−1 inside the screen houses and 8.6 W·m−2·minute−1 in the open-air. Air temperature was greater inside the screen houses whereas wind gusts were higher in the open-air. Reference evapotranspiration accumulation averaged 3.2 mm·day−1 inside the screen houses and 4.2 mm·day−1 in the open-air. There was no difference in cumulative rainfall between screen houses and open-air. The antipsyllid screen houses reduced solar radiation, maximum wind gust, and reference evapotranspiration (ETo). The environmental conditions inside the protective screen houses are suitable for grapefruit production.

A single hybrid parameter-based model for calibrating hargreaves-samani coefficient in Nigeria

The present research was designed to locally calibrate Hargreaves-Samani computing model (HS) in twenty-one (21) locations with their corresponding coastal and interior regions in Nigeria employing a single hybrid parameter-based model to obtain the adjusted Hargreaves-Samani coefficient (AHC) for Nigerian environment. To achieve this purpose, meteorological parameters such as extraterrestrial solar radiation, maximum sunshine duration, minimum and maximum temperatures were employed as input parameters to compute the original HS model and equally calibrate the original HS model. The monthly AHCs were obtained by multiplying the 0.17 by the monthly ratio of the observed global solar radiation (H) to H calculated from original HS model. The average value was obtained per station. These observed AHC values were considered as the target values for the development of hybrid parameter-based models (HP) for every station used for calibrating original HS model. On the whole, the result from the statistical indicators confirmed that the locally calibrated HS model performed better than the original HS model in all stations (including coastal and interior regions) investigated. Both the original and calibrated HS models underestimated H at annual timescale, but the calibrated HS model provided closer average values with H, which could confirm the good performances of the calibrated HS model. Therefore, the calibrated HS model obtained in this research could be highly recommended for estimating H in Nigeria when only temperature data are available.

Radiation knowledge among radiographers and radiography students

Objective To evaluate the knowledge of radiation among radiographers and radiography students in NepalMethods A validated questionnaire was conducted among radiographers and radiography students in 24th annual meeting and workshop of Nepal Radiological Society (NRS) on 10th September, 2015. The survey included multiple choice questions (MCQs) related to demographic characteristics (age, gender), academic qualification, work experience and knowledge of radiation. The data were analyzed using SPSS software version 21.0.Results Of total 102 respondents, 68.6% (70) were students and 31.4% (32) were radiographers. There were 65 male and 37 female with age ranging from 18 to 45, mean 23.70±5.11 years. Out of 14 MCQs related to knowledge of radiation, maximum score was 14 and minimum 5 with mean 9.99±1.94 (mean percentage 71.35%) (radiographers 10.63±2.10, 75.89% and students 9.70±1.80, 69.28%) respectively. Most participants failed in questions related to radiation units, minimum safe distance during portable radiography, fluoroscopy, and cancer risk of chest radiograph.Conclusion Overall awareness and knowledge of radiation was satisfying with definite possibilities for further improvement through regular trainings, workshops and continuing medical education (CME) programs related to radiation protection and safety. Furthermore, it is an urgent requirement of national radiation protection act in Nepal

Ab Initio Analysis of Charge Carrier Dynamics in Organic-Inorganic Lead Halide Perovskite Solar Cells

ABSTRACTToday’s conversion of solar energy into electricity is based on silicon, which is pure, eventually crystalline, and its most efficient transitions are away from solar radiation maximum. The continuous search of efficient photovoltaic materials has recently focused on lead-halide organic-inorganic perovskite materials due to the very flexible, sustainable, and forgiving procedure of their fabrication, which is successful even if the concentrations of precursors, and temperature regimes deviate from optimal values. In addition to simple fabrication, this class of materials provides impressively high efficiency of photovoltaic (PV) cells. Attention to these materials helps to understand the mechanisms of their high efficiencies and to identify other materials with same type of properties. This work presents computational analysis of photo-induced processes in perovskite materials at ambient temperatures.

Prediction of yellow lupin yield (Lupinus luteus L.) for northern Poland using weather-crop model

Prediction of yellow lupin yield (Lupinus luteus L.) for northern Poland using weather- -crop model. The paper presents an analysis of the impact of meteorological factors (solar radiation, maximum, minimum and mean temperature, precipitation) on the development and yield of yellow lupin Parys cultivar in the northern Poland in the years 1987-2008. Using multiple regression methods (linear and quadratic function) created regression equations that were estimated using the coefficients of determination (R2, R2 adj and R2 pred - using the Cross Validation procedure). Selected regression equation used to estimate the yield of yellow lupin, using generated - by means of model WGENK - daily values of global radiation, maximum and minimum temperature, precipitation, and climate change scenario GISS Model E for Central Europe. Examined dependencies weather-yield of lupine seeds (cultivar Parys) allowed the application of the chosen model to forecast yields from the time when the values are independent variables in the model by the end of the growing season. The comparison of distributions of actual and simulated yields shows that real yields are slightly (by 0.06 t·ha-1) higher than those generated for 2 × CO2 conditions.