Modelling of the effects of environmental factors on rice grain discoloration incidence in Corrientes province,Argentina

Rice grain discoloration (RGD) is a disease of complex aetiology for which there are no resistant varieties. Due to the need to better define the environmental conditions that favour the disease, the aims of this work were to (i) identify the predominant fungi associated, (ii) determine the meteorological variables most closely related, and (iii) develop preliminary weather-based models to predict binary levels of RGD incidence. After analysing 123 rice grain samples under natural infection conditions from rice-cropping regions throughout Corrientes province, Argentina, we found that RGD was mainly associated with Alternaria padwickii (14.2%) and Microdochium albescens (13.7%). The strongest associations between weather variables and RGD incidence were observed in a susceptible critical period (Scp) that extended from the rice flowering stage until 870 accumulated degree days (Scp lasting 32 days, ±7 days). The binary response logistic model including the weather variables DPrecT (which combined the effect of the simultaneous daily occurrence of precipitation lower than 12 mm and air temperature between 13 and 28°C), and DDMnT (sum of the exceeding amounts of daily min temperature from 23°C), was the most appropriate, showing prediction accuracy (PA) values of 84.6%. The univariate model that included DPrecT presented a PA of 82.1%. The logistic regression techniques here used to develop weather-based models to estimate the probabilities of occurrence of binary levels of RGD can not only help to clarify and quantify the environmental effect on the development of RGD but also be useful tools to be included in future management strategies.     

From foe to friend: geographical and environmental factors and the control and eradication of smallpox in India

Due to the highly visible nature of the disease, smallpox received a lot of attention from the colonial and independent Indian governments. An assessment of the changing official views about the impact of geographical and environmental factors on modes of variola causation and control presents insights into themes that are generally ignored in the existing historiography. Rather than being synchronised efforts, imposed top-down, provincial level officials in charge of running vaccination programmes were able to retain a great degree of autonomy and shape the nature of local immunisation drive. As a result, vaccination work in the country was often disjointed, marked by official disagreements about the usefulness of certain strategies and technological inputs, with these trends being most noticeable in rural areas. Thus, this study seeks to highlight the importance of recognising--and studying--the fractured nature of medical and public health administration in the South Asian sub-continent.     

Impact of environmental factors on the dependency of litter biomass in carbon cycling of Hooghly estuary,India

Litterfall of the mangroves and its subsequent decomposition is an important mechanism in terms of productivity and nutrient cycle of that ecosystem. Present study emphasizes on the significance of litter biomass and role of environmental factors impacting this process. Mangrove litter undergoes degradation and decomposition and serves as the main source of carbon in different forms within the system, mangrove forests adjacent to the creeks at Sagar Island of the Hooghly–Matla estuarine ecosystem. This system receives a major load of carbon from adjacent mangrove forest in the form of litterfall throughout the year. Keeping in view the effect of environmental factors on litterfall and dynamics of carbon, machine learning method has been applied for this study. Different forms of carbon and environmental factors like temperature, salinity, pH, dissolved oxygen are estimated following standard procedure. Correlation, redundancy analysis and LASSO (Least Absolute Shrinkage and Selection Operator) regression are done in order to know the impact of environmental variables on carbon pool dynamics and effect of litterfall on the carbon pools in soil and water. The results reflect a strong correlation among the studied environmental factors and carbon pool dynamics. It has been revealed from the LASSO prediction results that each carbon pool is sensitive to a separate set of environmental factors.     

The distribution of the Greater horse-shoe bat, Rhinolophus ferrum-equinum, during hibernation, in relation to environmental factors

Hibernation is a vital factor in the ability of bats to survive in temperate countries where insect availability is drastically reduced in winter. The value of hibernation in survival lies in the reduction of the bat's metabolic rate to very low levels, thus reducing their food requirements.
The selection of a site which fulfils the physiological requirements of hibernation must be important in the survival of the Greater horse-shoe bat. The present study shows that temperature is particularly important in the selection of a precise position for hibernation. The temperature required, however, varies throughout the winter.
In England this bat finds suitable conditions in caves, mines, tunnels, cellars, and house attics. All are dark where the bats are found and offer protection from predators. These considerations are not sufficient to explain the distribution of this bat in hibernation.
The present study shows that a large proportion of the population feeds outside the hibernaculum at times during the hibernation period. The evidence suggests that starvation is a cause of death. Hence it is not only the conditions inside the hibernacula which are important in the winter survival of a bat population. The environmental conditions outside may be just as vital.
The Greater horse-shoe bat is vulnerable since the bulk of its population depends upon relatively few sites. Its reproductive rate is very low and active conservation is needed in England, since populations are small. If conservation is to be successful however, both the physical conditions within hibernacula, and the environmental conditions outside will have to be satisfactory.     

Patterns of tree growth in relation to environmental variability in the tropical dry deciduous forest at Mudumalai, southern India

Tree diameter growth is sensitive to environmental fluctuations and tropical dry forests experience high seasonal and inter-annual environmental variation. Tree growth rates in a large permanent plot at Mudumalai, southern India, were examined for the influences of rainfall and three intrinsic factors (size, species and growth form) during three 4-year intervals over the period 1988–2000. Most trees had lowest growth during the second interval when rainfall was lowest, and skewness and kurtosis of growth distributions were reduced during this interval. Tree diameter generally explained <10% of growth variation and had less influence on growth than species identity or time interval. Intraspecific variation was high, yet species identity accounted for up to 16% of growth variation in the community. There were no consistent differences between canopy and understory tree growth rates; however, a few subgroups of species may potentially represent canopy and understory growth guilds. Environmentally-induced temporal variations in growth generally did not reduce the odds of subsequent survival. Growth rates appear to be strongly influenced by species identity and environmental variability in the Mudumalai dry forest. Understanding and predicting vegetation dynamics in the dry tropics thus also requires information on temporal variability in local climate.     

Distribution of shorebirds at the Berg River estuary, South Africa, in relation to foraging mode, food supply and environmental features

Foraging densities of Curlew Sandpipers Calidris ferruginea and Grey Plovers Pluvialis squa-tarola at the Berg River estuary, South Africa, are examined in relation to prey and habitat attributes.
There is a substantial overlap in the prey species eaten by Curlew Sandpipers and Grey Plovers, but the distribution patterns of the two species within the estuary could not be explained by the same prey attributes.
The distribution of tactilely foraging Curlew Sandpipers was determined largely by the numerical abundance of nereid worms. They foraged preferentialiy on muddy rather than sandy substrata, but their distribution could not be explained on the basis of substratum penetrability. The density of visually foraging Grey Plovers was correlated with the biomass, rather than abundance, of the larger of the two common nereids on the estuary. The favoured foraging area of Grey Plovers had a high vegetation cover, but their foraging dispersion was not influenced by substratum type.
The energy intake rates of Curlew Sandpipers were broadly inversely related to their foraging density, although the rate of prey capture was maximal at high prey density. These birds may use neighbour success rates in selecting foraging sites. Energy intake rates of Grey Plovers were very consistent across the estuary, suggesting that individuals occupy or defend areas which provide access to comparable food resources.     

Demographic, reproductive, medical, and environmental factors in relation to gastroschisis.

To identify risk factors for gastroschisis other than drug use in pregnancy, an analysis of data collected in a case-control surveillance program of birth defects (1976-1990) was conducted. Drug use is considered in Werler et al., Teratology, 45:361-367, 1992. Maternal demographic, reproductive, and medical factors, and first trimester environmental exposures, were compared between 76 gastroschisis cases and 2,581 malformed controls. A strong inverse association was found for maternal age: relative to women 30 years or older, relative risks for 25-29, 20-24, and less than 20-year-old women were 1.7, 5.4, and 16, respectively. Multivariate relative risks (and 95% confidence intervals) for alcohol use were as follows: for 1-5 drinks per week, 1.6 (0.7-3.4); for greater than or equal to 6 drinks per week, 2.5 (0.9-6.8); for a maximum of 1-4 drinks at any one time, 0.8 (0.4-1.6); and for a maximum of greater than or equal to 5 drinks, 2.8 (1.2-6.5). With the effect of age taken into account, no associations were identified for cigarette smoking, consumption of caffeinated or decaffeinated coffee, unplanned pregnancy, 12 or less years of education, or a parity of two or more. Other medical and reproductive factors, including weight gain, vaginal bleeding, nausea or vomiting, influenza, "other" infection, and history of spontaneous abortion or elective abortion did not increase the risk.     

Partitioning controls on Amazon forest photosynthesis between environmental and biotic factors at hourly to interannual timescales

Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance‐derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light‐use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R² = 0.77) to interannual (R² = 0.80) timescales. At hourly timescales, we found that 75% of observed GEP variability could be attributed to environmental variability. When aggregating GEP to the longer timescales (daily, monthly, and yearly), however, environmental variation explained progressively less GEP variability: At monthly timescales, it explained only 3%, much less than biotic variation in canopy photosynthetic light‐use efficiency, which accounted for 63%. These results challenge modeling approaches that assume GEP is primarily controlled by the environment at both short and long timescales. Our approach distinguishing biotic from environmental variability can help to resolve debates about environmental limitations to tropical forest photosynthesis. For example, we found that biotically regulated canopy photosynthetic light‐use efficiency (associated with leaf phenology) increased with sunlight during dry seasons (consistent with light but not water limitation of canopy development) but that realized GEP was nonetheless lower relative to its potential efficiency during dry than wet seasons (consistent with water limitation of photosynthesis in given assemblages of leaves). This work highlights the importance of accounting for differential regulation of GEP at different timescales and of identifying the underlying feedbacks and adaptive mechanisms.     

Further observations on clinical, histopathological, and immunological features of borderline disseminated cutaneous leishmaniasis caused by Leishmania (Leishmania) amazonensis

Leishmania (Leishmania) amazonensis has for some time been considered as the causative agent of two distinct forms of American cutaneous leishmaniasis (ACL): localized cutaneous leishmaniasis (LCL), and anergic diffuse cutaneous leishmaniasis (ADCL). Recently, a new intermediate form of disease, borderline disseminated cutaneous leishmaniasis (BDCL), was introduced into the clinical spectrum of ACL caused by this parasite, and in this paper we record the clinical, histopathological, and immunological features of eight more BDCL patients from Brazilian Amazonia, who acquired the disease in the Pará state, North Brazil. Seven of them had infections of one to two years' evolution and presented with primary skin lesions and the occurrence of metastases at periods varying from six to 12 months following appearance of the first lesion. Primary skin lesions ranged from 1-3 in number, and all had the aspect of an erythematous, infiltrated plaque, variously located on the head, arms or legs. There was lymphatic dissemination of infection, with lymph node enlargement in seven of the cases, and the delayed hypersensitivity skin-test (DTH) was negative in all eight patients prior to their treatment. After that, there was a conversion of DTH to positive in five cases re-examined. The major histopathological feature was a dermal mononuclear infiltration, with a predominance of heavily parasitized and vacuolated macrophages, together with lymphocytes and plasma cells. In one case, with similar histopathology, the patient had acquired his infection seven years previously and he presented with the largest number of disseminated cutaneous lesions. BDCL shows clinical and histopathological features which are different from those of both LCL and ADCL, and there is a good prognosis of cure which is generally not so in the case of frank ADCL.     

海南岛热带低地雨林群落水平植物功能性状与环境因子相关性随演替阶段的变化

以功能性状为基础的方法可以用来探讨植物群落中功能性状如何响应环境并揭示植物生态策略的潜在驱动力,但有关功能性状与环境因子之间的关系随植物群落演替变化的研究仍然匮乏.作者以海南岛热带低地雨林刀耕火种弃耕后处于不同演替阶段的次生林(包括弃耕后恢复15年、30年及60年的次生林)和老龄林为对象,通过群落学调查和对木本植物的功能性状及样地环境因子的测定,分析了群落水平植物功能性状与环境因子关系随演替阶段的变化规律.结果表明,随着演替的进行,林冠开阔度、土壤养分、比叶面积、叶片氮含量、叶片磷含量和叶片总有机碳含量逐渐降低,叶片干物质含量、木材密度、潜在最大高度逐渐升高,而土壤水分和叶片钾含量变化不大.多元逐步回归分析表明,影响群落水平植物功能性状的主要环境因子随演替阶段而发生显著的变化,在15年、30年和60年的次生林及老龄林中,对群落水平植物功能性状影响最大的环境因子依次为土壤有机质和pH值、林冠开阔度和土壤总磷含量、土壤总钾和有效磷含量,以及土壤有机质含量和磷含量.同一功能性状在不同演替阶段受到不同环境因子的控制,同时各功能性状又能够对不同演替阶段所处的特殊环境产生一定的适应性.     

Exploratory Spatio-Temporal Data Analysis (ESTDA) of Dengue and its association with climatic,environmental, and sociodemographic factors in Punjab,India

Routine health data is rich in information but underutilised for research in Low and Middle-Income countries. The present study was carried out to understand spatiotemporal patterns of dengue and its association with risk factors using routine data from health and allied sectors. ESTDA included estimation of dengue incidence rates, time series features and correlation coefficients up to the sub-district level. Scatter plots and correlation coefficients were used to identify relationships between covariates. Dengue incidence in 2015–19 was 47.76, 33.64, 52.03, 49.71, and 33.36 per 100,000, respectively, with a mean (SD) age of 34.33 (16.78) years and the majority being males (63.94%). Dengue had significant cross-correlation, non-linear relationships, and spatio-temporal associations with climatic, environmental, and socio-demographic risk factors. Significant autocorrelation of dengue occurrence was present at a lag of one month with seasonal patterns. The reproducible open-source algorithms add value to existing Routine Health Information Systems, and the findings will enable the development of Spatio-temporal models in future research. The research was done using R version 4.1.0.     

Observations on the relation between phytoplankton diversity and environmental factors in the Vaal River at Balkfontein,South Africa

The relationship between specific environmental factors as independent variables and temporal changes in phytoplankton community structure in the Vaal River (a turbid system) during 1984 was investigated by employing different diversity indices. Temporal changes in community structure reflected temporal changes in certain environmental factors. Phytoplankton diversity, measured with Shannon-Wie H' and Hurlbert PIE indices, was related firstly to discharge and discharge derived variables (such as SO₄, Si, N and P loading) and secondly to turbidity derived variables (such as euphotic zone depth). Discharge appears to be of prime importance in affecting diversity. Observations were made that shed new light on conditions contributing to the development of an August peak (dominated by Stephanodiscus hantzschii fo. tenuis and Micractinium pusillum) in phytoplankton concentration. Increased environmental stress may reduce the number of sensitive species, thus reducing interspecific competition between tolerant species which could then exploit the — for them — more favourable conditions resulting in an increase in their numbers to peak concentrations.     

The mystery of underground death: cell death in roots during ontogeny and in response to environmental factors

Programmed cell death (PCD) is an essential part of the ontogeny of roots and their tolerance/resistance mechanisms, allowing adaptation and growth under adverse conditions. It occurs not only at the cellular and subcellular level, but also at the levels of tissues, organs and even whole plants. This process involves a wide spectrum of mechanisms, from signalling and the expression of specific genes to the degradation of cellular structures. The major goals of this review were to broaden current knowledge about PCD processes in roots, and to identify mechanisms associated with both developmental and stress‐associated cell death in roots. Vacuolar cell death, when cell contents are removed by a combination of an autophagy‐associated process and the release of hydrolases from a collapsed vacuole, is responsible for programming self‐destruction. Regardless of the conditions and factors inducing PCD, its subcellular events usually include the accumulation of autophagosome‐like structures, and the formation of massive lytic compartments. In some cases these are followed by the nuclear changes of chromatin condensation and DNA fragmentation. Tonoplast disruption and vacuole implosion occur very rapidly, are irreversible and constitute a definitive step toward cell death in roots. Active cell elimination plays an important role in various biological processes in the life history of plants, leading to controlled cellular death during adaptation to changing environmental conditions, and organ remodelling throughout development and senescence.     

Some observations on the fish nurseries along the lake Kinneret shores: the interrelationships between species, and the influence of environmental factors

Observations were made of characteristic nursery areas along the southern and western coasts of Lake Kinneret, Israel, during the years 1982–84. Cyprinid and cichlid fingerlings were found to have different specific habitats. Most cyprinid species are of palaearctic origin, and prefer low water temperatures. Fingerlings of some species of cyprinids have exclusive habitats. A common characteristic of all the species is the direct relationship between body size and water depth. The presence of cichlid fingerlings in the nursery areas during the day is directly related to the occurrence of sunlight and to water temperature. An important finding was the time of dispersion of the cichlid fingerlings, which is when they attain a size ? 5 cm and weight of ? 3 g. Stocking of the lake with cichlid fingerlings below 3 g is not recommended.     

Above- and belowground biomass in relation to environmental factors in temperate grasslands, Inner Mongolia

Above- and belowground biomasses of grasslands are important parameters for characterizing re- gional and global carbon cycles in grassland ecosystems. Compared with the relatively detailed in- formation for aboveground biomass (AGB), belowground biomass (BGB) is poorly reported at the re- gional scales. The present study, based on a total of 113 sampling sites in temperate grassland of the Inner Mongolia, investigated regional distribution patterns of AGB, BGB, vertical distribution of roots, and their relationships with environmental factors. AGB and BGB increased from the southwest to the northeast of the study region. The largest biomass occurred in meadow steppe, with mean AGB and BGB of 196.7 and 1385.2 g/m2, respectively; while the lowest biomass occurred in desert steppe, with an AGB of 56.6 g/m2 and a BGB of 301.0 g/m2. In addition, about 47% of root biomass was distributed in the top 10 cm soil. Further statistical analysis indicated that precipitation was the primary determinant factor in shaping these distribution patterns. Vertical distribution of roots was significantly affected by precipitation, while the effects of soil texture and grassland types were weak.     

Mass stranding of striped dolphin, Stenella coeruleoalba, at Augusta, Western Australia: notes on clinical pathology and general observations.

Seventeen striped dolphins, Stenella coeruleoalba, were found stranded on a West Australian beach. Three animals died before a rescue attempt was made and a further three died during the rescue. The remaining dolphins were released 24 km offshore and were not seen again. One dolphin was noted to have a broken mandible. Evidence of physical trauma to the other dolphins was minimal; one adult female was observed with some peeling skin. Blood was collected for analysis. All dolphins were slightly dehydrated and had a leukogram typical of a stressed animal. Plasma biochemistry reflected primary muscle trauma. There were no clues to the cause of the stranding; observed pathology reflected damage that occurred as a direct consequence of stranding.     

油蒿资源利用效率在生长季的相对变化及对环境因子的响应

为了探明西北半干旱区典型沙生植物油蒿(Artemisia ordosica)叶水平资源利用效率的相对变化及对环境因子的响应机制, 该研究于2018年5-10月, 使用LI-6400XT便携式光合仪测定了毛乌素沙地油蒿叶片的净光合速率(P_n)、蒸腾速率(E)、叶表面光合有效辐射(PAR_l)、叶表面温度(T_l)、叶表面相对湿度(RH_l), 在实验室计算叶片单位面积氮含量(N_area), 分析了叶片氮利用效率(NUE)、水分利用效率(WUE)、光利用效率(LUE)与环境因子之间的关系及NUE、WUE、LUE之间的相对变化。研究结果表明, 在充足且稳定光强下油蒿的P_n主要受温度的影响, NUE、WUE与VPD_l、T_l之间具有显著负相关关系, NUE、WUE与LUE间为正相关关系, NUE、WUE和LUE最大值分别发生在5、7和9月, 分别为9.43 μmol CO₂·g^-1·s^-1、3.86 mmol·mol^-1、0.04 mol·mol^-1, 资源利用效率的变化主要受P_n的影响。温度通过影响植物N分配来改变P_n, 进而影响着资源利用效率, WUE与LUE显著正相关, 对构建荒漠区生态系统能量交换过程模型有重要意义。     

海州湾春季短蛸的栖息分布特征及其与环境因子的关系

近年来,我国近海多种重要渔业资源处于不同程度的衰退状态,而短蛸具有生命周期短、生长迅速的特点,在我国近海经济渔获产量中占重要地位。然而,有关短蛸的栖息分布特征及其与环境因子的关系尚缺乏研究,不利于更好地保护和利用其资源。本研究根据2011年和2013—2017年春季海州湾的渔业资源和环境因子调查数据,采用随机森林模型、人工神经网络模型和广义提升回归模型3种机器学习方法分析了短蛸的栖息分布特征及其与环境因子的关系。结果表明: 随机森林模型的拟合效果和预测能力在3种模型中优势较大,选择该模型进行分析表明,底层水温、水深和底层盐度对短蛸的栖息分布有较大影响。短蛸的相对资源密度随底层水温、水深和底层盐度的增加均呈先上升后下降趋势。根据FVCOM模型模拟的环境数据,应用随机森林模型预测了短蛸在海州湾海域的栖息分布,发现短蛸主要分布在34.5°—35.8° N、119.7°—121° E之间的海域。