minimum relative humidity
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2021 ◽  
Author(s):  
Phrutsamon Wongnak ◽  
Maude Jacquot ◽  
Séverine Bord ◽  
Albert Agoulon ◽  
Frédéric Beugnet ◽  
...  

Abstract Ixodes ricinus ticks (Acari: Ixodidae) are the most important vector for Lyme borreliosis in Europe. As environmental and climate changes might affect the distribution and activity of tick populations, this study aimed to determine the effects of environmental factors, i.e., meteorological, bioclimatic, and habitat characteristics on questing activity of I. ricinus nymphs across diverse climatic types in France over an 8-year period. Questing activity was observed using a repeated removal sampling design with a cloth-dragging technique in 11 sampling sites from 7 tick observatories from 2014 to 2021 at approximately 1-month intervals, involving 631 sampling campaigns. Three phenological patterns were observed, potentially following a climatic gradient. The mixed-effects negative binomial regression revealed that observed nymph counts were driven by different interval-average meteorological variables, including one-month average temperature, previous-season average temperature, and half-year average minimum relative humidity. The interaction effects indicated that the phenology in colder climates peaked differently from that of warmer climates. Also, the land cover characteristics that support the highest baseline abundance were moderate forest fragmentation with transition borders with agricultural areas. Finally, our model could potentially be used to predict seasonal human-tick exposure risks in France that could contribute to mitigating Lyme borreliosis risks.


Author(s):  
Keshav Mehra ◽  
Veer Singh

Background: Chickpea, Cicer arietinum which is considered as a “King of pulses” get adversely affected by several biotic and abiotic stresses, out of which gram pod borer, Helicoverpa armigera (Hübner) is the major one. The damage caused by H. armigera starts from vegetative growth and continues till maturity of the crop. This pest is causes 25 to 70 per cent pod damage in chickpea but in favorable conditions pod damage goes upto 95 per cent. Methods: Present study was carried out during, rabi, 2014-15 and 2015-16 at Research Farm, College of Agriculture, Bikaner (Rajasthan). Correlation coefficient was worked out with weather parameters such as temperature (maximum and minimum), relative humidity (maximum and minimum), rainfall and sunshine hours. Multiple linear forms of regression model were also used to assess the effect of the weather parameters on the incidence of pod borer. Result: The studies revealed that peak larval population of gram pod borer was recorded in the second fortnight of February thereafter, population declined abruptly. The larval population of pod borer on chickpea occurred low at vegetative and flowering stages and high at pod formation as well as at grain developmental stages. The temperature (maximum and minimum) and sunshine hours had significant positive correlation with larval population during rabi, 2015-16. The maximum relative humidity showed significant negative correlation during rabi, 2015-16 whereas, minimum relative humidity showed significant negative correlation with larval population during both the seasons. The rainfall showed significant positive correlation during rabi, 2014-15.


Author(s):  
Eder Cano-Pérez ◽  
Steev Loyola ◽  
Fabián Espitia-Almeida ◽  
Jaison Torres-Pacheco ◽  
Dacia Malambo-García ◽  
...  

Leptospirosis is an acute febrile disease that mainly affects developing countries with tropical climates. The complexity and magnitude of this disease is attributed to socioeconomic, climatic, and environmental conditions. In this study, in a 10-year period from 2008 to 2017, the relationship between human leptospirosis cases and climatic factors in Cartagena de Indias, Colombia were evaluated. Monthly leptospirosis cases, climatic variables, and macroclimatic phenomena (El Niño and La Niña) were obtained from public datasets. Local climatic factors included temperature (maximum, average, and minimum), relative humidity, precipitation, and the number of precipitation days. Time series graphs were drawn and correlations between cases of leptospirosis and climatic variables considering lags from 0 to 10 months were examined. A total of 360 cases of leptospirosis were reported in Cartagena during the study period, of which 192 (53.3%) were systematically notified between October and December. Several correlations were detected between the number of cases, local climatic variables, and macroclimatic phenomena. Mainly, the increase of cases correlated with increased precipitation and humidity during the La Niña periods. Herein, seasonal patterns and correlations suggest that the climate in Cartagena could favor the incidence of leptospirosis. Our findings suggest that prevention and control of human leptospirosis in Cartagena should be promoted and strengthened, especially in the last quarter of the year.


2021 ◽  
Vol 23 (4) ◽  
pp. 428-434
Author(s):  
PRABIR KUMAR GARAIN ◽  
BHOLANATH MONDAL ◽  
SUBRATA DUTTA

A study was conducted to find out the influence of weather factors, soil temperature and soil moisture on the incidence of Sclerotium rolfsii Sacc. induced collar rot disease in betelvine (Piper betle L.), during 2016 to 2018. Fourteen soil and weather factors, taken from the agrometeorological observatory located at instructional farm of Ramkrishna Ashram Krishi Vigyan Kendra, Nimpith and recorded from a nearby betelvine boroj, were subjected to multiple regression, binary logistic regression and canonical discriminant analysis to develop a suitable disease forewarning model. The binary logistic model, Y(0/1) = 5.899 + 0.865 (Tmax) – 0.569 (SM) + 0.097 (BRHmin) was able to predict the disease risk with 78 per cent accuracy and correctly classified 94 per cent of cases during model validation in 2018. The weekly averages of maximum temperature (Tmax), soil moisture (SM) and minimum relative humidity inside the boroj (BRHmin) were found to be the most significant predictors of disease incidence, in this model. The soil moisture at 69 - 72 per cent of field capacity, minimum temperature of 25 - 27oC, maximum temperature of 33 - 36oC, average soil temperature of 28 - 30oC, minimum relative humidity of 60 - 72 per cent inside the boroj and maximum relative humidity of 83 - 89 per cent inside the boroj were found to be highly congenial for collar rot disease incidence in betelvine under coastal saline zone of West Bengal.


2021 ◽  
Vol 2083 (3) ◽  
pp. 032001
Author(s):  
Tiantian Jin ◽  
Lei Wang ◽  
Yuguang Zhao ◽  
Luming Shen

Abstract Based on the data of environmental monitoring stations and meteorological stations in Qinhuangdao from May 2017 to May 2020, the variation characteristics of O3 and precursors (NO2 and CO) as well as their relationship with meteorological elements were analyzed. The results showed that the daily average concentration of O3-8 h in Qinhuangdao increased year by year. The monthly average concentration of O3-8 h was high in summer and low in winter, and the peak appeared in June. The diurnal variation of O3 concentration was unimodal structure, and the concentration increased in the afternoon, but it decreased at night. The concentration of NO2 and CO was inversely correlated with O3, and the peak value of NO2 in March could be related to frequent cold air activity and increased burning of loose coal. The meteorological elements favorable for the occurrence of ozone pollution weather in Chengde were total solar radiation irradiance greater than 1000W/m2, the daily maximum temperature greater than 33 °C, and the daily minimum relative humidity less than 40% and 65%∽80%, southerly wind or southwest wind.


Author(s):  
Lung-Chang Chien ◽  
L.-W. Antony Chen ◽  
Ro-Ting Lin

Abstract Background The associations between meteorological factors and coronavirus disease 2019 (COVID-19) have been discussed globally; however, because of short study periods, the lack of considering lagged effects, and different study areas, results from the literature were diverse and even contradictory. Objective The primary purpose of this study is to conduct more reliable research to evaluate the lagged meteorological impacts on COVID-19 incidence by considering a relatively long study period and diversified high-risk areas in the United States. Methods This study adopted the distributed lagged nonlinear model with a spatial function to analyze COVID-19 incidence predicted by multiple meteorological measures from March to October of 2020 across 203 high-risk counties in the United States. The estimated spatial function was further smoothed within the entire continental United States by the biharmonic spline interpolation. Results Our findings suggest that the maximum temperature, minimum relative humidity, and precipitation were the best meteorological predictors. Most significantly positive associations were found from 3 to 11 lagged days in lower levels of each selected meteorological factor. In particular, a significantly positive association appeared in minimum relative humidity higher than 88.36% at 5-day lag. The spatial analysis also shows excessive risks in the north-central United States. Significance The research findings can contribute to the implementation of early warning surveillance of COVID-19 by using weather forecasting for up to two weeks in high-risk counties.


2021 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Gleisis Alvarez-Socorro ◽  
Mario Carnesoltas-Calvo ◽  
Alis Varela-de la Rosa ◽  
José C. Fernández-Alvarez

One of the manifestations of severe local storms is strong linear winds, which are known as a downburst and which are capable of causing great losses to the country’s economy and society. Knowing which factors in the atmosphere are necessary for the occurrence of this phenomenon is essential for its better understanding and prediction. The objective of this study was to analyze the possible physical factors that accelerate downdrafts in the storm clouds in Cuba. To do so, 10 study cases simulated with the weather research and forecasting (WRF) model at 3 km of the spatial resolution were used. The factors capable of discriminating between downbursts and thunderstorms without severity were obtained. These were the absorption of latent heat by evaporation and fusion, the equivalent potential temperature difference between the level of maximum relative humidity in the low levels and of minimum relative humidity in the middle levels, the speed of the downdraft, and the downdraft available convective potential energy (DCAPE). Unlike previous research, they discriminated against updraft buoyancy and energy advection, both at the middle levels of the troposphere.


Author(s):  
S.D. Divija ◽  
Meena Agnihotri

Background: The solitary endo-larval parasitoid Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) is an important biocontrol agent of H. armigera in chickpea ecosystem. Abiotic factors are likely to affect the insect host and activity of its parasitoid. Therefore, the present study was conducted to understand the impact of weather factors and different dates of sowing on per cent parasitization of Helicoverpa armigera (Hübner) by Campoletis chlorideae (Uchida) in chickpea ecosystem.Methods: In this field-laboratory investigation were carried out at Pantnagar during the cropping season of 2017-18. Twenty-five larvae of H. armigera (first and second instars) were collected randomly at weekly basis from untreated chickpea crop. In the laboratory, the collected larvae were reared till parasitoid emergence and observed for per cent parasitisation. Result: The observation recorded revealed that mean seasonal parasitism by Campoletis on larvae of H. armigera was found to be 21%, 43.5% and 34.5% in early (20th October), normal (11th November) and late sown crop (1st December), respectively. Various abiotic parameters like maximum and minimum temperature, maximum and minimum relative humidity registered high level of significant association with per cent parasitization in early and normal sown crop compared to the low level of association in late sown crop. The multiple regression analysis showed that the combined effect of all the meteorological parameters were responsible for 90%, 57.9% and 30.5% variation in per cent parasitization in early, normal and late sown crop, respectively.


2021 ◽  
Vol 11 (1) ◽  
pp. 73-87
Author(s):  
Achmad Basuki ◽  
Ali Awaludin ◽  
Bambang Suhendro ◽  
Suprapto Siswosukarto

This study was aimed to investigate the creep behavior of laminated veneer lumber (LVL) Sengon,especially under the application of compression and tension stress parallel-to-the-grain. In IndonesiaLVL made from the fast-growing Sengon (Paraserianthes falcataria) species is designed to be usedas a substitution for solid wood in building construction. Creep test was conducted on the specimenswith reference to the ASTM D143‐09 standard test methods for small clear specimens of timber.Moreover, the constant loads were made equal to about 20%, 30%, and 40% of the 60% ultimateload derived from the static test and the creep test was conducted in a chamber having an averagetemperature of 25oC and minimum relative humidity of 65%. The results of creep test for a period of90 days showed that the creep factors were 0.51, 0.52, and 0.41, respectively for the specimens undertension stress level of 20%, 30%, and 40%, respectively. In the case of specimen under compressionstress parallel-to-the-grain, the creep factors were 0.42, 0.41, and 0.31, respectively, for stress levelequals to 20%, 30%, and 40%. It can be concluded that the creep factor under tension stress is slightlyhigher than that of specimens under compression stress, and these obtained creep factors are muchlesser than the values provided in the code.


2021 ◽  
Vol 69 (2) ◽  
Author(s):  
Ricardo Antonio Marenco ◽  
Saul Alfredo Antezana-Vera

Introduction: Climatic variables show a seasonal pattern in the central Amazon, but the intra-annual variability effect on tree growth is still unclear. For variables such as relative humidity (RH) and air vapor pressure deficit (VPD), whose individual effects on tree growth can be underestimated, we hypothesize that such influences can be detected by removing the effect of collinearity between regressors. Objective: This study aimed to determine the collinearity-free effect of climatic variability on tree growth in the central Amazon. Methods: Monthly radial growth was measured in 325 trees from January 2013 to December 2017. Irradiance, air temperature, rainfall, RH, and VPD data were also recorded. Principal Component Regression was used to assess the effect of micrometeorological variability on tree growth over time. For comparison, standard Multiple Linear Regression (MLR) was also used for data analysis. Results: Tree growth increased with increasing rainfall and relative humidity, but it decreased with rising maximum VPD, irradiance, and maximum temperature. Therefore, trees grew more slowly during the dry season, when irradiance, temperature and VPD were higher. Micrometeorological variability did not affect tree growth when MLR was applied. These findings indicate that ignoring the correlation between climatic variables can lead to imprecise results. Conclusions: A novelty of this study is to demonstrate the orthogonal effect of maximum VPD and minimum relative humidity on tree growth.


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