Hot Dry Summers Research Articles

Environmental and climatic significance of the Pliocene-Pleistocene calcretes in North Africa

The North African calcretes formed during the Plio-Pleistocene are a prominent and stratigraphically significant palaeoclimatic marker. We studied the calcrete along a north–south transect in Tunisia that crosses the climatic boundaries between the latitudes 33° and 37° N to elucidate the palaeoenvironmental and climatic significance of the calcrete for the Plio-Pleistocene. Macroscopic, petrographic, Scanning Electron Microscopy (SEM), and Cathodoluminescence (CL) observations obtained in the field and from thin sections of the non-powdery horizons of all sites allowed to identify 4 facies: Pisolithic (limestones with clast(s) coated by laminae), laminar (limestones with a succession of laminae), massive brecciated (brecciated limestones), and groundwater facies (limestones with no biogenic features). Notably, soil-forming processes were evident at all sites except for those situated further south, which exhibited characteristics indicative of a groundwater environment. The comparison with modern analogues suggests for our study area the climate was similar to modern central Spain (Hot-summer Mediterranean climate Csa) in central Tunisia which is, in turn, similar to the modern climate in North Tunisia. The climate was characterized by strong seasonal contrast: higher winter rainfall than today followed by long dry hot summers modified by a North-South gradient. This gradient was the result of the interplay between westerly winter winds and the orographic effect of the Atlas Mountains confirming the North Atlantic origin of precipitations. We conclude that during the late Pliocene to early Pleistocene, the climate in Northern Africa was more humid than today, with enhanced winter rainfall at all study sites probably at the same time of the establishment of Saharan humid periods. These humid phases may have been long enough, spanning more than 10.000 years, to reduce recharged groundwater salinity and, subsequently, form thick calcareous soil.

Optimizing the thermal performance of residential buildings in Jordan

This work investigates the influence of building form, natural ventilation, and window shading passive strategies on the thermal performance and thermal comfort of three residential building forms, namely rectangular, L-shape, and U-shape, in the hot-dry summer in Amman, Jordan. The thermal performance of buildings is studied using indoor air temperature, and the thermal comfort is evaluated according to ASHRAE-55 and Fanger’s models. The buildings’ models are designed using the SketchUp plugin OpenStudio and then plugged into the EnergyPlus simulator. It is obtained that when natural ventilation and shading devices are considered together, the indoor air temperature is notably dropped up to 8.85 °C in the daytime and 12.70 °C at nighttime, which improves the thermal comfort of all building forms. Generally, rectangular building exhibits the best thermal behavior under optimum conditions. U-shape presents the best thermal behavior for the primary conditions, and it records the lowest out-of-comfort percentage time during the day and achieves the highest comfortable percentage after considering the window’s area control.

ANALYSIS OF CLIMATE CHANGE EFFECT ON EXTREME PRECIPITATION EVENT IN CONSTANTINE ALGERIA

Extreme precipitation events are critical climatic indicators that offer substantial insights into climate change and its variability. This study aims to investigate whether climate change has impacted precipitation frequencies in the Constantine region of Algeria, known for its semi-arid climate with hot-dry summers and cold-wet winters. Temporal variations of monthly air temperature and precipitation were analyzed from 1981 to 2014. Statistical analysis identified a threshold for estimating monthly extreme precipitation during the period from 1981 to 2005 using the Gumbel distribution method. Additionally, a climatic projection of precipitation for return periods of 50 (t = 50) and 100 (t = 100) years was conducted to forecast extreme precipitation values in the future. The results indicate a gradual increase in precipitation levels during the study period, with values generally remaining below extreme thresholds. This suggests no significant escalation in the occurrence of extreme precipitation events. Furthermore, the findings highlight that climate change has had a more pronounced impact on altering air temperature than on influencing extreme precipitation trends.

Hormonal response to recurrent seasonal stress in coastal and mountain scabiouses growing in their natural habitat: linking ABA and jasmonates with photoprotection.

Plant species distribution across ecosystems is influenced by multiple environmental factors, and recurrent seasonal stress events can act as natural selection agents for specific plant traits and limit species distribution. For that, studies aiming at understanding how environmental constraints affect adaptive mechanisms of taxonomically closely related species are of great interest. We chose two Scabiosa species inhabiting contrasting environments: the coastal scabious S. atropurpurea, typically coping with hot-dry summers in a Mediterranean climate, and the mountain scabious S. columbaria facing cold winters in an oceanic climate. A set of functional traits was examined to assess plant performance in these congeneric species from contrasting natural habitats. Both S. atropurpurea and S. columbaria appeared to be perfectly adapted to their environment in terms of adjustments in stomatal closure, CO2 assimilation rate and water use efficiency over the seasons. However, an unexpected dry period during winter followed by the typical Mediterranean hot-dry summer forced S. atropurpurea plants to deploy a set of photoprotective responses during summer. Aside from reductions in leaf water content and Fv/Fm, photoprotective molecules (carotenoids, α-tocopherol and anthocyanins) per unit of chlorophyll increased, mostly as a consequence of a severe chlorophyll loss. The profiling of stress-related hormones (ABA, salicylic acid and jasmonates) revealed associations between ABA and the bioactive jasmonoyl-isoleucine with the underlying photoprotective response to recurrent seasonal stress in S. atropurpurea. We conclude that jasmonates may be used together with ABA as a functional trait that may, at least in part, help understand plant responses to recurrent seasonal stress in the current frame of global climate change.

The effects of 2-D and 3-D urban landscape metrics on mean radiant temperature in hot-arid Phoenix and Tempe, Arizona, USA

The composition and configuration of the built environment affect intra-urban heat variability and human thermal exposure. We investigated how 2-D and 3-D building and vegetation characteristics, represented by various landscape metrics, affect the mean radiant temperature (MRT) distribution in Phoenix and Tempe, Arizona, USA, to determine which urban form characteristics are most important for minimizing thermal exposure. For a hot-dry summer day with low wind speed and a maximum air temperature of 43.3 °C, the relationship between 1-m resolution MRT data and seventeen 2-D and 3-D landscape metrics were analyzed at the Census block (micro) and urban (macro) scale. The landscape metrics were calculated with FragStat from a Digital Surface Model, a 3-D point cloud obtained from high-resolution (0.5-m) USGS LiDAR data, and a 1-m resolution land use/land cover map classified from the 2015 National Agriculture Imagery Program (NAIP) data. Hourly MRT for June 27, 2012, was simulated using the SOlar LongWave Environmental Irradiance Geometry (SOLWEIG) model. After testing for autocorrelation in hourly MRT using Moran's I, the relationship between landscape metrics and MRT outcomes was analyzed using correlation coefficients and multiple linear regression. The best predictive power was achieved using 2-D and 3-D metrics together, with an explanation MRT of 86 % (8:00 h) to 96 % (12:00 h). The five most important factors were 3-D vegetation height, 2-D percent tree surface cover, 3-D building height, 2-D building edge density, and the 3-D vegetation height coefficient of variation. Results show that MRT is driven by the composition and configuration of 2-D and 3-D urban features. The horizontal arrangement impacts MRT through varying land cover, and the vertical extent influences shade patterns, with more complex urban forms providing more shade and lowering MRT. Findings advance our understanding of how urban design can reduce thermal exposure on hot days using passive cooling strategies that rely on changes in the configuration and composition of landscapes.

Comprehensive accuracy assessment of long-term geostationary SEVIRI-MSG evapotranspiration estimates across Europe

This study quantifies the accuracy of evapotranspiration (ET) estimates from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) geostationary sensor onboard the Meteosat Second Generation (MSG) satellites, along seven key dimensions, i.e., diurnal cycle, daily, intra-annual, inter-annual, ecosystem, climate zone, and products intercomparison. In situ measurements were collected at 54 eddy covariance (EC) sites to evaluate the accuracy of SEVIRI actual ET products (diurnal and daily SEVIRI-ETa) as well as reference ET (daily SEVIRI-ET0) covering the period from 2004 to 2018 across Europe. SEVIRI-ETa is produced by the Tiled ECMWF Surface Scheme of Exchange processes at the Land surface (TESSEL) model, while SEVIRI-ET0 is estimated by a combination of a thermodynamically-based and an atmospheric boundary layer model. This evaluation is further separated according to the land cover heterogeneity of the SEVIRI pixels across all 54 EC sites, using MODIS land cover data. The Root Mean Squared Error (RMSE), along with the Kling-Gupta efficiency (KGE) and their respective decompositions, were employed to quantify the errors.For diurnal SEVIRI-ETa estimates, we found that the KGE (RMSE [mm hour−1]) varied between −1.6 (0.04) to 0.8 (0.14), with a median value of 0.26 (0.07). Higher accuracy for diurnal SEVIRI-ETa was obtained in the summer and during the mid-day time. For daily SEVIRI-ETa, the KGE (RMSE [mm day−1]) varied between −0.88 (0.43) to 0.93 (1.79), with a median value of 0.6 (0.77) and for daily SEVIRI-ET0 the KGE (RMSE [mm day−1]) varied between 0.51 (0.40) to 0.94 (1.50), with a median value of 0.77 (0.57). For daily SEVIRI-ETa, intra-annual accuracy was low from January to March, increased in the mid-year, and then began to decline from November to December. Although accuracy remained relatively stable during the middle of the year, it varied considerably in the winter period. In the inter-annual dimension, the mid-year positive KGE values and distributions changed over time from 2004 to 2018. In spatial dimensions, the highest accuracy was in peat and grassland ecosystems, and the lowest in cropland ecosystem, with similar patterns observed in the boreal snow fully humid warm summer and warm temperate fully humid hot summer climate zones. Regarding SEVIRI-ET0 results, similar to SEVIRI-ETa, intra-annual accuracy was low in the first quarter of the year and the last one but high in the mid-year. In the inter-annual dimension, unlike SEVIRI-ETa, almost an identical pattern was observed for the mid-year positive KGE values, demonstrating only a slight change in SEVIRI-ET0 accuracy during 2004–2018. However, the highest accuracy was found in crop ecosystem, while the lowest was in forest ecosystem, reflecting similar trends in the warm temperate fully humid hot summer and warm temperate summer dry hot summer climate zones. The observed range of median RMSE changed between 0.4 and 1.5 mm day−1, also suggests a reasonable accuracy for SEVIRI-ET estimates in all spatial domains.Our results showed that the main trends in the accuracies (median KGEs) of SEVIRI-ET (both ETa and ET0) remained similar in separated homogeneous and heterogeneous sites and were comparable to combined sites among the dimensions. Through error decomposition, we discerned that SEVIRI-ET estimates performed particularly well in explaining inter-annual and spatial variabilities. Furthermore, the intercomparison of ET products revealed that SEVIRI satellite-derived ETa exhibited the strongest correlation with in situ ET measurements across all ecosystem types and climate zones, outperforming other products (such as MODIS, PML, GLEAM, and BESS). The ET estimates from other products exhibited lower standard deviation errors and were in closer agreement with the in situ measurements. This study provides the first comprehensive evaluation of the accuracy of SEVIRI diurnal and daily ET products across Europe, which may serve as a stimulus for further optimized selection of these products by potential users for various applications.

Vegetation dynamics over 18 years in response to seasonal climatic conditions and land use in the Kamiesberg mountains of the succulent Karoo, South Africa

Projections of vegetation change in response to future global change conditions are challenged by the lack of long-term, empirical data on how vegetation responds to the variability in climatic conditions. This is particularly true for biodiverse systems that are threatened by climate change such as the winter-rainfall Succulent Karoo biome of southern Africa. In this study we analyse long-term data (2002–2019) of two biodiversity observatories from the Kamiesberg Mountains in the Succulent Karoo. We employed the R package GLMMtmb to analyse counts of abundance and estimated cover values of vegetation as response variables and seasonal Standardised Precipitation-Evapotranspiration Index (SPEI), annual livestock density, topography and soil surface structure as predictors for the interannual change of life forms under low and high land use intensity. We compared the life form composition at the two contrasting land use types and found the cover and abundance of leaf succulents to be higher under low grazing intensity and that of stem succulents to be higher under high grazing intensity. The cover and abundance of herbaceous life forms varied over the years depending on the seasonal weather conditions. Our GLMM results reveal counts of abundance to be a sensitive predictor for population dynamics in various herbaceous and shrub life form types. Estimated cover values showed less of a response to interannual differences in the environmental drivers. All life forms responded strongly to high humid and cool conditions in the second half of the winter rainfall period, when the temperatures increase again. The abundance of leaf-succulent and non-succulent shrubs also responded positively to moderate conditions towards the end of the dry season. The extensive and hot dry summer season in turn had a significant negative effect on the survival of particularly young plants with low cover. Cover values showed no response to the conditions of the late dry season and were generally less sensitive to the variance in seasonal climatic conditions. Our results suggest that future changes in interannual patterns in climatic conditions will affect life form composition of the vegetation.

First report of the hard tick Ixodes Ricinus on dogs in Lebanon.

Ixodes ricinus is a hard tick that can infest a large array of hosts. It is mostly abundant in the cool, humid deciduous and coniferous woods and forests of Europe. All I. ricinus life stages are potential vectors of many diseases, most notably Lyme disease, which affects millions of people yearly. Lebanon, an Asian Mediterranean country with mild cool winters and hot dry summers, lacks many reports concerning ticks. A study on tick abundance and identification on dogs presented to veterinary facilities, over the course of the years 2020 and 2021 was done. Several species of ticks were identified, with the least abundant being I. ricinus. To the best of our knowledge, this is the first report of the tick species in the country. More studies on the distribution and abundance of I. ricinus in Lebanon should be made in order to properly estimate the pathogens it carries, and consequently implement the appropriate prophylactic measures concerning public health.

SEASONAL AND HOST-ASSOCIATED VARIATION IN BOT FLY (OESTRIDAE: CUTEREBRINAE) PARASITISM OF LAGOMORPHS ACROSS AN ARID-LAND ECOSYSTEM IN SOUTHERN NEW MEXICO.

Bot flies (Oestridae: Cuterebrinae) are obligate mammalian parasites that complete the larval stage of their life cycle under the skin of their host. Most detailed studies of bot fly larval disease ecology have been conducted in temperate deciduous zone rodent systems. To understand the relative importance of seasonal and spatial factors, as well as factors intrinsic to the host, in underpinning the likelihood and extent of parasitism by bot flies in non-rodent hosts as well as in arid-land ecosystems, we examined the dynamic for black-tailed jackrabbit (Lepus californicus) and desert cottontail (Sylvilagus audubonii) parasitism by bot fly larvae (Cuterebra spp.) across 7 repeatedly sampled sites spread across approximately 500 km of the Chihuahuan Desert ecoregion of southern New Mexico. This environment is characterized by a climate that includes hot dry summers and cool to cold dry winters, as well as strongly seasonal summer monsoonal rains. Lagomorphs are a common mid-sized mammal in these landscapes. Bot fly parasitism was strongly seasonal, with peak prevalence and abundance in the spring, and there was spatial variation in the extent of parasitism between collection sites. Additionally, jackrabbits in better body condition were less likely to be parasitized (as indicated by kidney fat index). We did not find sex-based differences in bot fly parasitism between male and female jackrabbits. Thus, in arid-land ecoregions, abiotic factors are likely the primary driver of the bot fly-host interaction, whereas factors intrinsic to the host were of secondary importance for characterizing the interactions of bot flies and lagomorphs.

Optimum Time of Insemination after Onset of Oestrus in Holstein – Friesian Dairy Cows in the Peri-urban Khartoum (Sudan)

The aim of this study was to determine the optimum time of insemination after onset of oestrus in Holstein-Friesian dairy cows. 146 and 92 Cows were randomly assigned to the control and prostaglandin F2α treated groups respectively. The experimental animals were then visually observed for oestrus for a period of twelve months. 188 and 99 inseminations were given to the control and prostaglandin F2α treated groups respectively. The inseminations were given at time intervals of 1-6, 7-12, 13-18, and 19-24 hours after onset of oestrus during winter, hot dry summer and hot wet summer. During the three seasons, inseminations were carried out in cows at postpartum interval of 41-60, 61-80, 81-100, 101-120, 121 and over days. The trial was conducted in Cows at parities 1 and 2 as a group, and parities 3 and over as a separate group. The optimum time of insemination to achieve the highest conception rates was at 13-18 hours in the control group of Cows. Winter had the highest conception rates compared to other seasons. Cows at postpartum intervals of 121 and over days had the highest conception rates. Conception rates in cows at parities 1 and 2 had the highest conception rate compared to other parities. The present study revealed that the control group of cows had the highest conception rates when inseminations were at 13 – 18 hours after onset of oestrus compared to prostaglandin F2α treated cows.

An Investigation into Thermal Performance of Mist Water System and The Related Consumption Energy

Experimental tests were conducted to investigate the thermal performance (cooling effect) of water mist system consisting of 5μm volume median diameter droplets in reducing the heat gain entering a room through the roof and the west wall by reducing the outside surface temperature due to the evaporative cooling effect during the hot dry summer of Baghdad/Iraq. The test period was Fifty one days during the months May, June, and July 2012. The single test day consists of 16 test hours starting from 8:00 am to 12:00 pm. The results showed a reduction range of 1.71 to 15.5℃ of the roof outside surface temperature and 21.3 to 76.6% reduction in the daily heat flux entering the room through the roof compared with the case of not using water mist system. Also the results show a reduction range of 1.3 to 18.8℃ in the wall outside surface temperature. Finally numerical simulation with ANSYS-FLUENT.14 was conducted to compare its results with the experimental results of the roof and wall tests.

Precipitation timing and soil substrate drive phenology and fitness of Arabidopsis thaliana in a Mediterranean environment

Abstract In Mediterranean climates, the timing of seasonal rains determines germination, flowering phenology and fitness. As climate change alters seasonal precipitation patterns, it is important to ask how these changes will affect the phenology and fitness of plant populations. We addressed this question experimentally with the annual plant species Arabidopsis thaliana. In a first experiment, we manipulated the date of rainfall onset and recorded germination phenology on sand and soil substrates. In a second experiment, we manipulated germination date, growing season length and mid‐season drought to measure their effects on flowering time and fitness. Within each experiment, we manipulated seed dormancy and flowering time using multilocus near‐isogenic lines segregating strong and weak alleles of the seed dormancy gene DOG1 and the flowering time gene FRI. We synthesized germination phenology data from the first experiment with fitness functions from the second experiment to project population fitness under different seasonal rainfall scenarios. Germination phenology tracked rainfall onset but was slower and more variable on sand than on soil. Many seeds dispersed on sand in spring and summer delayed germination until the cooler temperatures of autumn. The high‐dormancy DOG1 allele also prevented immediate germination in spring and summer. Germination timing strongly affected plant fitness. Fecundity was highest in the October germination cohort and declined in spring germinants. The late flowering FRI allele had lower fecundity, especially in early fall and spring cohorts. Projections of population fitness revealed that: (1) Later onset of autumn rains will negatively affect population fitness. (2) Slow, variable germination on sand buffers populations against fitness impacts of variable spring and summer rainfall. (3) Seasonal selection favours high dormancy and early flowering genotypes in a Mediterranean climate with hot dry summers. The high‐dormancy DOG1 allele delayed germination of spring‐dispersed fresh seeds until more favourable early fall conditions, resulting in higher projected population fitness. These findings suggest that Mediterranean annual plant populations are vulnerable to changes in seasonal precipitation, especially in California where rainfall onset is already occurring later. The fitness advantage of highly dormant, early flowering genotypes helps explain the prevalence of this strategy in Mediterranean populations. Read the free Plain Language Summary for this article on the Journal blog.

Regeneration from seeds in a temperate native flora: A climate‐smart and natural–capital‐driven germination risk modelling approach

Societal Impact StatementExceptionally rainy winters and hot–dry summers are becoming the new normal around the United Kingdom. The effects of these climatic changes can already be seen in forests and grasslands, agricultural fields and even in our own gardens, as native plants try to keep pace with them. In this study, the seed germination of the native flora of Wakehurst, in the Southeast England, was analysed to identify potential threats to the long‐term persistence of selected species, which are part of the natural landscape of this area. Recommendations are provided for ecological restoration interventions which aim to maintain the different potential benefits those plants can provide to people.Summary Seeds play an important role in plant adaptation to human‐driven climate change. In this study, we applied a multilevel modelling of thermal germination responses of native temperate plants, to understand how global warming could affect their reproduction and the potential benefits they provide, as part of their natural capital. We identified Wakehurst (Southeast England, UK), as our study system. We modelled thermal seed germination parameters of the native flora as a whole and according to different uses categories (e.g., medicinal or food plants), through a phylogenetic meta‐analysis of publicly available data from Kew's Millennium Seed Bank (MSB). We also carried out a comparative germination study for MSB seed lots of 20 selected species. Finally, we quantified the germination risk, by comparing current and predicted environmental temperatures with thermal germination parameters at flora, uses categories and species level. Under future climatic scenarios, germination of the native flora will be at higher risk in spring than in autumn. Fitted quadratic models, although affected by phylogeny, did not show major differences among uses categories. Species with a narrow window of cold germination temperatures could be more at risk than those with warm optimal temperatures. Restoration activities should target species from phylogenetically clustered uses categories, to avoid losing their benefit provisions, and implement climate‐smart seed sourcing for high‐risk species. This multilevel germination modelling approach, based on collections and available data from conservation seed banks, can be applied to selected floras and regions to inform climate‐smart ecological restoration activities, while accounting for their natural capital.

Selenium Removal by Sediments and Plants at the Constructed Pariette Wetlands, Utah (USA)

Selenium (Se) contamination of public lands and water is a result of irrigated agriculture and mining activities in areas rich in Se geologic deposits. Pariette Draw is part of the northern Colorado Plateau and is an area of concern for Se contamination in the Pariette Wetlands. Pariette Wetlands, a wetland built in the 1970s to provide wildlife habitat, is distinguished by its arid climate and a short growing season of hot dry summers followed by cold winters with several months below freezing. An understanding of how Se is mobilized and removed within the wetland will provide management strategies that minimize and mitigate Se contamination and promote sustainable ecosystem services. The data collected in 2012 and 2014 was the first comprehensive spatial and temporal analysis of Se in all environmental compartments (bird eggs, macroinvertebrates, plants, sediments, and water) of an arid wetland ecosystem in the Colorado Plateau. Water, sediment, and plant tissue samples were collected and analyzed to determine Se’s spatial and temporal variation in Pariette Wetlands. Se concentrations in water, sediment, and plants were evenly distributed throughout wetlands. No significant differences were found in plant Se concentrations between samples collected in 2012 (447 ± 44 ug kg−1) or 2014 (541 ± 42 μg kg−1), indicating that plant Se did not vary temporally during sampling. Aquatic plant species (e.g., pondweed (Potamogeton filiformis), 743 ± 66 μg kg−1 and watermilfoil (Myriophyllum spicatum), 874 ± 122 μg kg−1) accumulated more Se than plant species growing at the edges of the ponds (e.g., hardstem bulrush (Schoenoplectus acutus), 368 ± 37 μg kg−1 and cattail (Typha), 420 ± 43 μg kg−1). Plant roots (1045 ± 110 μg kg−1) accumulated more Se than aboveground vegetation (flowers, 228 ± 17 μg kg−1 or stems, 224 ± 19 μg kg−1). Relative to Se retained by sediments (75%), plants were not an extensive reservoir of wetland Se (<5%) but still may pose a risk to animals feeding on plant tissue. Thus, phytoremediation of Se does not appear to be a viable tool for Se mitigation in wetlands of arid climates with a short growing season, such as those located in the Colorado Plateau.

Fruit Cuticle Composition in ‘Arbequina’ Olive: Time–Course Changes along On-Tree Ripening under Irrigated and Rain-Fed Conditions

Olive (Olea europaea L.) fruit and derived products play a pivotal role in the Mediterranean diet, to which they contribute their gastronomic value and their health-promoting properties. The fruit cuticle constitutes the interface between the plant and the surrounding environment, and it modulates relevant traits such as water loss, mechanical resistance, and susceptibility to pests and rots. Hence, a better knowledge of fruit cuticle properties and the impact thereupon of agronomic factors could help improving olive grove management. In this work, time–course changes in fruit cuticle yields and composition were assessed during the on-tree ripening of ‘Arbequina’ olives obtained from irrigated or rain-fed trees grown at a commercial grove located in El Soleràs (Catalonia, Spain), where low annual rainfall occur together with cold winters and hot dry summers. Significantly higher wax contents were observed for rain-fed than for irrigated fruits, both in relative (% over total cuticle) and in absolute terms (from 231 to 840 µg cm−2 and from 212 to 560 µg cm−2, respectively, contingent upon the maturity stage), in agreement with their proposed role as a barrier against water loss. Compositional differences in cuticular waxes and in cutin monomers were also detected between irrigated and rain-fed olives, with major changes involving significantly higher loads per surface area of triterpenoids and ω-hydroxy fatty acids in the latter. In contrast to the load and composition of cuticular wax, no apparent impact of irrigation was observed on either total cuticle yields or cuticle thickness.

Characterizing temperature and precipitation multi‐variate biases in 12 and 2.2 km UK Climate Projections

AbstractMany impactful weather and climate events include two or more variables (like temperature or precipitation) having high or low values (e.g., hot dry summers). Understanding biases in the relationship between modelled variables is important for characterizing uncertainties in the risks associated with compound events. We present a framework for evaluating the relationships between different variables (multi‐variate bias). We illustrate our approach with UK temperature and precipitation, using HadUK‐Grid observations and two model ensembles (12 and 2.2 km horizontal resolution) of the HadGEM3 regional model used in UK Climate Projections both forced with the same driving conditions. There are distinct regional patterns in the biases of both the Pearson correlation coefficients and coefficients of linear regression between temperature and precipitation in both resolutions, for example, large areas of positive biases in the Pearson correlation coefficients across the United Kingdom in winter, and negative biases across most of England in summer. We combine the Pearson correlation coefficients and bias in the coefficient of linear regression into a combined metric and consider regions where either the bias in the coefficient of linear regression or the bias in Pearson correlation coefficient is significantly dominant over the other. By considering only days with similar North Atlantic driving conditions using Met Office Weather Patterns we can identify regions with significant differences between the two model resolutions that are attributable to the difference in model resolution and structural design. The root mean square error (RMSE) of correlation bias across the United Kingdom is reduced in the 2.2 km compared to the 12 km model data in each season except summer where it is broadly similar. For Weather Pattern 2 (North Atlantic Oscillation positive) days the RMSE for correlation coefficient and the coefficient of linear regression is twice as large than for all conditions.

Viruses and Phytoplasma Reported on the Most Important Vegetable Crops in Syria: A Review

Ismaeil, F., J. Mando, M. Alkhalaf and S.G. Kumari. 2023. Viruses and Phytoplasma Reported on the Most Important Vegetable Crops in Syria: A Review. Arab Journal of Plant Protection, 41(4): 444-458. https://doi.org/10.22268/AJPP-41.4.444458 Syria is famous for cultivation of many different vegetable crops in most governorates during both winter and summer growing seasons, due to its Mediterranean moderate climate conditions, characterized by a mild winter and a hot dry summer. Vegetables cultivation is a very important sector of the Syrian agriculture, as it represents an important source of income for growers and a source of hard currency through export. The most important vegetables cultivated in Syria are solanaceous crops (potato, tomato, sweet potato, pepper and eggplant), cucurbits (watermelon, melon, cucumber, squash and pumpkin), legumes (broad bean, green bean, green pea and cowpea), cruciferaceous (white cabbage and white cauliflower) and other species such as: green onion, green garlic, lettuce, okra … etc. These vegetable crops are affected by many diseases caused by different causal agents, among them, viruses, viroids and phytoplasmas that are considered the most important pathogens causing many serious and significant diseases. In Syria, during the past forty years, many viruses and few phytoplasmas were investigated and most of them (especially viruses) were recorded on these vegetable crops through many field surveys carried out to evaluate their sanitary status and to determine the economic losses and damages caused by those pathogens. Tens of studies were implemented with the aim of identifying those causal agents on the most important vegetable crops grown in the country and finding out the appropriate approaches for their effective control. Many available and appropriate diagnostic methods such as biological, serological and molecular techniques were used to assess the sanitary status of these crops. Keywords: Diseases, Vegetable crops, Viruses, Phytoplasmas, Syria

A mediterrán növényalkalmazás jelene és jövőbeli lehetőségei

In Hungary, the Mediterranean influence is more and more strongly featured typically by considerable climatic extremes between winter and summer. The Mediterranean vegetation has adapted to these changes and tolerates dry hot summers and mildly rainy winters. It will gain more and more space in the future both in public and private areas – mainly on the southern slopes of South Transdanubia and the Balaton Highlands, later maybe on the same southern slopes of Buda Mountains and the Velence Mountains, and afterwards in some areas of the Northern Middle Mountains. Thus it is useful to gain knowledge about the Mediterranean coastland’s vegetation and profit from it. Keeping in mind the economic water management, it is advisable to decide on drought and frost-tolerant species while planting them in a harmonic and decorative manner in orchards and lawn areas in the future. This is what the presented recommendations are for.

CLIMATE RECONSTRUCTION OF SOUTHERN UKRAINE IN THE OLIGOCENE ON THE BASIS OF SPORE-POLLEN STUDY DATA BY THE COEXISTENCE APPROACH METHOD

Based on the data of spore-pollen studies of the Oligocene sediments of Southern Ukraine, a reconstruction of the Oligocene climate of this region was carried out using the latest method of coexistence approach. For each of the intervals of Oligocene time (early Borysphenian, late Borysphenian, Molochanian, Sirogozian, Askanian, and Hornostaivian) the values of the following climatic parameters were calculated: mean annual temperature, coldest month temperature (January), warmest month temperature (July), mean annual precipitation, highest month precipitation, lowest month precipitation, warmest month precipitation. It was established that the paleoclimate was warm, close to subtropical, with dry hot summers. It is classified as Csa type according to Köppen. A trend of gradual cooling and aridization of the climate within Southern Ukraine during the Oligocene was revealed. In the middle of the Oligocene (Molochanian — Sirogozian) an episode of noticeable warming and drying: an increase of continentality of the climate was recorded (an increase of mean annual temperature and a decrease of precipitation in the wettest month, a decrease of precipitation in the driest month and a decrease of precipitation in the warmest month), which corresponds to the period of the least development of the sea basin within the Southern Ukraine in the Oligocene.

Changing Epidemiology of Acute Respiratory Infections in Under-Two Children in Dhaka, Bangladesh.

Objectives: Risk factors for acute respiratory infections (ARIs) in community settings are not fully understood, especially in low-income countries. We examined the incidence and risk factors associated with ARIs in under-two children from the Microbiota and Health study.Methods: Children from a peri-urban area of Dhaka (Bangladesh) were followed from birth to 2 years of age by both active surveillance of ARIs and regular scheduled visits. Nasopharyngeal samples were collected during scheduled visits for detection of bacterial facultative respiratory pathogens. Information on socioeconomic, environmental, and household conditions, and mother and child characteristics were collected. A hierarchical modeling approach was used to identify proximate determinants of ARIs.Results: Of 267 infants, 87.3% experienced at least one ARI episode during the first 2 years of life. The peak incidence of ARIs was 330 infections per 100 infant-years and occurred between 2 and 4 months of age. Season was the main risk factor (rainy monsoon season, incidence rate ratio [IRR] 2.43 [1.92–3.07]; cool dry winter, IRR 2.10 [1.65–2.67] compared with hot dry summer) in the first 2 years of life. In addition, during the first 6 months of life, young maternal age (<22 years; IRR 1.34 [1.01–1.77]) and low birth weight (<2,500 g; IRR 1.39 [1.03–1.89]) were associated with higher ARI incidence.Conclusions: Reminiscent of industrialized settings, cool rainy season rather than socioeconomic and hygiene conditions was a major risk factor for ARIs in peri-urban Bangladesh. Understanding the causal links between seasonally variable factors such as temperature, humidity, crowding, diet, and ARIs will inform prevention measures.