seasonal fluctuation
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Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1297
Author(s):  
Peng-Wu Yin ◽  
Xian-Guo Guo ◽  
Dao-Chao Jin ◽  
Wen-Yu Song ◽  
Lei Zhang ◽  
...  

A 12-month consecutive investigation was made at Jingha village in southern Yunnan of southwest China from April 2016 to March 2017. A total of 2053 Indochinese forest rats (Rattus andamanensis Blyth, 1860) were captured and examined, which account for 84.69% (2053/2424) of all the animal hosts (rodents and other small mammals) at the investigation site. And 39.82% (13,531/33,980) of gamasid mites were identified from the body surface of R. andamanensis and they belong to 41 species, 10 genera, 3 subfamilies and 2 families. Of the 41 species of gamasid mites identified from R. andamanensis, Laelaps nuttalli Hirst, 1915 and Laelaps echidninus Berlese, 1887 were the most dominant with 70.63% and 20.67% of constituent ratios respectively. In monthly fluctuations of all the gamasid mites on R. andamanensis, the constituent ratio (Cr) and overall infestation mean abundance (MA) of the mites in 12 months showed two obvious peaks in January (winter season) and June (summer season). However, the two dominant mite species, L. nuttalli and L. echidninus, showed different patterns of seasonal fluctuations. Laelaps nuttalli occurred throughout the year, and its Cr and MA showed two prominent peaks in winter season (December and January) and summer season (June), which belongs to the summer-winter type of seasonal fluctuation. Laelaps echidninus also occurred on R. andamanensis throughout the year, but its Cr and MA showed only one peak in winter season (December and January), which belongs to the winter type of seasonal fluctuation. A negative correlation existed between two climatic factors (temperature and rainfall) and the infestations (Cr, prevalence PM and MA) of two dominant mite species (L. nuttalli and L. echidninus) on R. andamanensis (p < 0.05). Temperature and rainfall are considered to be two key factors that influence the seasonal fluctuations of the mites on the studied rat species.


2021 ◽  
Author(s):  
Suman Kumari ◽  
Lianthuamluaia ◽  
U. K. Sarkar ◽  
P. Mishal ◽  
G. Karnatak ◽  
...  

Abstract In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eutrophication due to disconnection from river that compromises the hydro-ecological functions. This requires systematic studies to assess the ecological health of the water bodies using different indices and suggest appropriate strategies to manage the resources. The zooplanktons are closely link with surrounding environment throughout their life cycles and change rapidly in their growth and population when changes occurs in the surrounding, hence act as potential indicator of eutrophication. The present study examined the assemblage pattern of zooplankton community and trophic state of two ecologically distinct oxbow lakes based on eco-hydrological characteristics and community structure of rotifers and planktonic crustaceans seasonally over a period of 2 years. Comprehensive trophic state index (mTSI), rotifer trophic state index (mTSIROT) and Crustacean based indices (TSICR) were used to assess the degree of eutrophication. The Kruskal-Wallis test confirmed the heterogeneity of the eco-hydrological factors between the oxbow lakes. A total of 68 zooplankton species were identified of which rotifers (69%), cladocerans (18%), copepods (3%), ostacods (3%) and protozoans (7%). Seasonal fluctuation of relative abundance and frequency of species in both lakes have been well presented. Both lakes showed transition from high meso-eutrophic to moderately eutrophic state with mTSI, mTSIrot and mTSIcr values of 54.90±11.71 and 56.95±15.64, 59.55±4.54 and 60.26±4.48, 55.79±4.76 and 60.00±4.03 in Khalsi (seasonally open) and Akaipur (closed) respectively. The Canonical Correspondence analysis (CCA) revealed water quality parameters comparison NO3-N, water temperature and pH have contributed more in enhancement of abundance of eutrophication indicator species Brachionus and Keratella. The TSIs values indicated a prompt aquaculture fisheries management measures like stocking of planktivorous fish (Labeo catla and Puntius sp.) for both the lakes before they reach in plunged state at which their restoration might become a challenge. An overview of worldwide use of rotifer and crustacean based indices in assessment of TSI has also been synthesized. The use of these zooplankton indices to evaluate the trophic status of the ecologically distinct lakes is highly recommended for water quality assessment and management. Based on this study strategies could be developed to plan and manage floodplain oxbow lakes for fisheries enhancement programme as well as as conservation of biodiversity.


2021 ◽  
Vol 8 ◽  
Author(s):  
Veerasak Punyapornwithaya ◽  
Katechan Jampachaisri ◽  
Kunnanut Klaharn ◽  
Chalutwan Sansamur

Milk production in Thailand has increased rapidly, though excess milk supply is one of the major concerns. Forecasting can reveal the important information that can support authorities and stakeholders to establish a plan to compromise the oversupply of milk. The aim of this study was to forecast milk production in the northern region of Thailand using time-series forecast methods. A single-technique model, including seasonal autoregressive integrated moving average (SARIMA) and error trend seasonality (ETS), and a hybrid model of SARIMA-ETS were applied to milk production data to develop forecast models. The performance of the models developed was compared using several error matrices. Results showed that milk production was forecasted to raise by 3.2 to 3.6% annually. The SARIMA-ETS hybrid model had the highest forecast performances compared with other models, and the ETS outperformed the SARIMA in predictive ability. Furthermore, the forecast models highlighted a continuously increasing trend with evidence of a seasonal fluctuation for future milk production. The results from this study emphasizes the need for an effective plan and strategy to manage milk production to alleviate a possible oversupply. Policymakers and stakeholders can use our forecasts to develop short- and long-term strategies for managing milk production.


Author(s):  
Alexios Lolas ◽  
Psofakis Pier ◽  
Ioannis T. Karapanagiotidis

The total lipid and protein content of the invasive caprellid amphipod Caprella scaura, from the biofouling communities of fish farm cages in the Pagasitikos Gulf were analyzed and compared among seasons. Proteins were the most abundant component (48.5 &ndash; 49.3%). Lipid content was relatively lower, with a wider range (6.7 &ndash; 34%) and showed a distinct seasonal fluctuation with high values in the winter population and a gradual decrease in spring and summer, with the lowest values in Autumn. Composition of the fatty acids profile was consistent among the seasons, with palmitic (16:0), Oleic (18:1n-9), Eicosapentanoic (20:5n-3)(EPA) and Docosahexanoic acid (22:6n-3 )(DHA) being the most abundant fatty acids. The presence of high levels of EPA and DHA fatty acids makes the species a potential candidate for use of these organisms in aquaculture.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 212-213
Author(s):  
Brad A Belstra

Abstract Identifying swine reproduction research opportunities, especially those that add value by addressing industry challenges and leveraging assisted reproductive technologies (ART) will be the focus of this talk. ART and genetic selection to increase pork production efficiency have been intertwined since the use of artificial insemination (AI) became widely adopted 30 years ago. Tremendous efficiency gains have been made in part by increasing litter size which is nearly 6 to 7 pigs larger today than it was in 1990. The increased farrowing duration and stillbirths, and decreased piglet birth weight, colostrum intake, and survival to weaning that has been associated with these larger litters are prime targets to be ameliorated with sow and pig management solutions. There is also clear evidence that pigs from smaller litters have the advantage of superior reproductive performance compared to those from larger litters. Thus, litter size and pre-weaning growth may need to be managed, or at least taken into account, to select the best boars and gilts for breeding stock and replacements. Any other accurate, early indicators of boar and gilt puberty, fertility, and lifetime productivity could add significant value. The seasonal fluctuation in fertility that has plagued pig production is costly and may be smoothed out by strategies that mitigate heat stress and improve health. Another opportunity to improve both pig and sow welfare may be intermittent suckling and induction of a fertile estrus and ovulation for breeding during lactation. Even more genetic and pig growth value could be added via AI with sex-sorted semen, if methods to better estimate boar fertility, deliver increased sperm quality, and more precisely synchronize or predict ovulation can be found to reduce the number of sperm required per female. Existing and evolving ART will synergize with genomics and gene editing technologies to unlock new levels of production efficiency.


2021 ◽  
Vol 9 (1) ◽  
pp. 3035-3044
Author(s):  
Siti Nurzakiah ◽  
Atang Sutandi ◽  
Gunawan Djajakirana ◽  
Untung Sudadi ◽  
Supiandi Sabiham

Quantification of CO2 flux from peat has been studied with various methods of measurement and data analysis. Several studies have applied regression analysis to assess carbon flux from tropical peatland as a function of groundwater level. Such an analysis simplified the complex nature of peat decomposition, which involved microbial activities. The study was conducted at Buatan Village, Siak Indrapura Regency, Riau Province, Indonesia. Soil sampling was done every month for a year observation, from July 2018 to June 2019. This study aimed to comprehend CO2 production from the respiration of heterotrophic components (Rh-CO2) as a function of soil properties determined by soil pH, N-NH4, N-NO3, available P, exchangeable-K, C-organic acids, and environmental factors that are determined by soil water content, and groundwater level. The study applied trenching experimentation to quantify Rh-CO2 flux by first removing plant roots from the trenching plot. The CO2 flux and groundwater level were measured for five consecutive days each month for a one-year period. Multiple regression analysis was performed to determine the main determinant for the Rh-CO2 flux. The results showed that seasonal fluctuation of Rh-CO2 flux, negatively correlated with available P (p = 0.037), and positively (p = 0.018) with C-substrate as C-organic acids but not with either of the speciated ones as acetic, lactic, citric, malic, nor oxalic acids. More specifically, the C-organic acids were found as the main determinant factor (p = 0.039) affecting the Rh-CO2 flux.


Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1202
Author(s):  
Jessica Cusato ◽  
Jacopo Mula ◽  
Alice Palermiti ◽  
Alessandra Manca ◽  
Miriam Antonucci ◽  
...  

Although studies show an annual trend for immunosuppressive drugs, particularly during different seasons, no data are available for antiretroviral drugs exposures in different periods of the year. For this reason, the aim of this study was to investigate an association between seasonality and antiretroviral drugs plasma concentrations. Antiretroviral drugs exposures were measured with liquid chromatography validated methods. A total of 4148 human samples were analysed. Lopinavir, etravirine and maraviroc levels showed seasonal fluctuation. In detail, maraviroc and etravirine concentrations decreased further in summer than in winter. In contrast, lopinavir concentrations had an opposite trend, increasing more in summer than in winter. The etravirine efficacy cut-off value of 300 ng/mL seems to be affected by seasonality: 77.1% and 22.9% of samples achieved this therapeutic target, respectively, in winter and summer, whereas 30% in winter and 70% in summer did not reach this value. Finally, age over 50 years and summer remained in the final multivariate regression model as predictors of the etravirine efficacy cut-off. This study highlights the seasonal variation in antiretroviral drugs plasma concentrations during the year, leading to a better understanding of inter-individual variability in drug exposures. Studies are required in order to confirm these data, clarifying which aspects may be involved.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Guilin Luo ◽  
Guangming Ren ◽  
Xiaojun Bao ◽  
Xili Yang ◽  
Teng Liu

There exists the problem of landslide reactivation due to the seasonal fluctuation of rainfall and reservoir water level annually. Based on a large number of GPS monitoring data of the landslide mass after impoundment of the Three Gorges Reservoir in Shiliushubao landslide area, the relationship between the external trigger factors and slope stability could be obtained. A finite element calculation model has been established for the stability analysis of the Shiliushubao landslide after impoundment from January 2004 to October 2009. Through the deformation characteristics of the landslide, it is shown that the landslide exhibited a stepwise pattern on the whole, which developed faster after impoundment and slowed down in rainy seasons. The trend of the curve kept roughly opposite to the fluctuation of the safety factor. It suggested that the stability of the landslide mass was closely related to the seasonal fluctuation of the rainfall and the reservoir level, and the landslide deposits demonstrated to be reactive with them. The subject provides a certain reference value on the landslide stability analysis and the risk assessment within a similar engineering geological condition.


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