growth parameter
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2022 ◽  
Vol 8 ◽  
Author(s):  
Shui-Kai Chang ◽  
Tzu-Lun Yuan ◽  
Simon D. Hoyle ◽  
Jessica H. Farley ◽  
Jen-Chieh Shiao

Growth shapes the life history of fishes. Establishing appropriate aging procedures and selecting representative growth models are important steps in developing stock assessments. Flyingfishes (Exocoetidae) have ecological, economic, and cultural importance to many coastal countries including Taiwan. There are 29 species of flyingfishes found in the Kuroshio Current off Taiwan and adjacent waters, comprising 56% of the flyingfishes taxa recorded worldwide. Among the six dominant species in Taiwan, four are of special importance. This study reviews aging data of these four species, documents major points of the aging methods to address three aging issues identified in the literature, and applies multi-model inference to estimate sex-combined and sex-specific growth parameters for each species. The candidate growth models examined included von Bertalanffy, Gompertz, Logistic, and Richards models, and the resulting optimal model tended to be the von Bertalanffy model for sex-combined data and Gompertz and von Bertalanffy models for sex-specific cases. The study also estimates hatch dates from size data collected from 2008 to 2017; the results suggest that the four flyingfishes have two spawning seasons per year. Length-weight relationships are also estimated for each species. Finally, the study combines the optimal growth estimates from this study with estimates for all flyingfishes published globally, and statistically classifies the estimates into clusters by hierarchical clustering analysis of logged growth parameters. The results demonstrate that aging materials substantially affect growth parameter estimates. This is the first study to estimate growth parameters of flyingfishes with multiple model consideration. This study provides advice for aging flyingfishes based on the three aging issues and the classification analysis, including a recommendation of using the asterisci for aging flyingfishes to avoid complex otolith processing procedures, which could help researchers from coastal countries to obtain accurate growth parameters for many flyingfishes.


Epidemiologia ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 639-659
Author(s):  
Sushma Dahal ◽  
Ruiyan Luo ◽  
Raj Kumar Subedi ◽  
Meghnath Dhimal ◽  
Gerardo Chowell

Nepal was hard hit by a second wave of COVID-19 from April–May 2021. We investigated the transmission dynamics of COVID-19 at the national and provincial levels by using data on laboratory-confirmed RT-PCR positive cases from the official national situation reports. We performed 8 week-to-week sequential forecasts of 10-days and 20-days at national level using three dynamic phenomenological growth models from 5 March 2021–22 May 2021. We also estimated effective and instantaneous reproduction numbers at national and provincial levels using established methods and evaluated the mobility trends using Google’s mobility data. Our forecast estimates indicated a declining trend of COVID-19 cases in Nepal as of June 2021. Sub-epidemic and Richards models provided reasonable short-term projections of COVID-19 cases based on standard performance metrics. There was a linear pattern in the trajectory of COVID-19 incidence during the first wave (deceleration of growth parameter (p) = 0.41–0.43, reproduction number (Rt) at 1.1 (95% CI: 1.1, 1.2)), and a sub-exponential growth pattern in the second wave (p = 0.61 (95% CI: 0.58, 0.64)) and Rt at 1.3 (95% CI: 1.3, 1.3)). Across provinces, Rt ranged from 1.2 to 1.5 during the early growth phase of the second wave. The instantaneous Rt fluctuated around 1.0 since January 2021 indicating well sustained transmission. The peak in mobility across different areas coincided with an increasing incidence trend of COVID-19. In conclusion, we found that the sub-epidemic and Richards models yielded reasonable short-terms projections of the COVID-19 trajectory in Nepal, which are useful for healthcare utilization planning.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2652
Author(s):  
Shirin Afzali ◽  
Sahand Mosharafian ◽  
Marc W. van Iersel ◽  
Javad Mohammadpour Velni

Global population growth has increased food production challenges and pushed agricultural systems to deploy the Internet of Things (IoT) instead of using conventional approaches. Controlling the environmental parameters, including light, in greenhouses increases the crop yield; nonetheless, the electricity cost of supplemental lighting can be high, and hence, the importance of applying cost-effective lighting methods arises. In this research paper, a new optimal supplemental lighting approach was developed and implemented in a research greenhouse by adopting IoT technology. The proposed approach minimizes electricity cost by leveraging a Markov-based sunlight prediction, plant light needs, and a variable electricity price profile. Two experimental studies were conducted inside a greenhouse with “Green Towers” lettuce (Lactuca sativa) during winter and spring in Athens, GA, USA. The experimental results showed that compared to a heuristic method that provides light to reach a predetermined threshold at each time step, our strategy reduced the cost by 4.16% and 33.85% during the winter and spring study, respectively. A paired t-test was performed on the growth parameter measurements; it was determined that the two methods did not have different results in terms of growth. In conclusion, the proposed lighting approach reduced electricity cost while maintaining crop growth.


2021 ◽  
Vol 8 (4) ◽  
pp. 207-210
Author(s):  
G. K. Upamanya ◽  
◽  
R. Brahma ◽  
R. Sarma ◽  
P. Sharma ◽  
...  

Oyster mushroom growers are generally confused about the scientific basis of the cultivation technology with regard to the best bag opening method after a spawn run. The present study was undertaken to find out the effect of four different methods of bag opening on yield, benefit cost ratio (BCR) and biological efficiency of oyster mushrooms during November, 2020 to March, 2021. The results indicated that treatment-2 (retaining the polythene bag for the entire cultivation period) exhibited significantly the highest yield (1644.61 g bed-1) followed by treatment-3 (opening top part of the polythene bag after spawn run) (1536.62 g bed-1), and treatment-1 (opening top and bottom part of the polythene bag (1468.82 g bed-1) and treatment-4 (complete removal of the polythene bag) (1111.19 g). The BCR was also found to be the highest (4.39) in treatment-2 followed by treatment-3 (4.09), treatment-1 (3.96) and treatment-4 (2.98). Retaining the polythene bag during the entire cultivation period was found to be the best method of cultivation with regard to biological efficiency (82.23%). Opening the top part of the polythene bag after the spawn run showed the biological efficiency of 76.83% which was followed by the treatment with opening the polythene bag from the top and bottom part of the bed (73.44%).The lowest biological efficiency (55.56%) was observed in the treatment in which the entire polythene bag was removed after a spawn run in darkroom. Mushroom growers may retain the polythene bag surrounding the mushroom bed during the entire cultivation period for better economic return.


2021 ◽  
Author(s):  
Maxime Tourte ◽  
Philippe Schaeffer ◽  
Vincent Grossi ◽  
Philippe M Oger

Microbes preserve membrane functionality under fluctuating environmental conditions by modulating their membrane lipid composition. Although several studies have documented membrane adaptations in Archaea, the influence of most biotic and abiotic factors on archaeal lipid compositions remains underexplored. Here, we studied the influence of temperature, pH, salinity, the presence/absence of elemental sulfur, the carbon source, and the genetic background on the core lipid composition of the hyperthermophilic neutrophilic marine archaeon Pyrococcus furiosus. Every growth parameter tested affected the core lipid composition to some extent, the carbon source and the genetic background having the greatest influence. Surprisingly, P. furiosus appeared to only marginally rely on the two major responses implemented by Archaea, i.e., the regulation of the ratio of diether to tetraether lipids and that of the number of cyclopentane rings in tetraethers. Instead, this species increased the ratio of glycerol monoalkyl glycerol tetraethers (GMGT, aka. H-shaped tetraethers) to glycerol dialkyl glycerol tetrathers (GDGT) in response to decreasing temperature and pH and increasing salinity, thus providing for the first time evidence of adaptive functions for GMGT. Besides P. furiosus, numerous other species synthesize significant proportions of GMGT, which suggests that this unprecedented adaptive strategy might be common in Archaea.


2021 ◽  
Author(s):  
Tertius Swanepoel Brand ◽  
I. Terblanche ◽  
Daniel Andre Van der Merwe ◽  
J.W. Jordaan ◽  
Olga Dreyer

Abstract This study aimed at estimating models to predict the growth and feed intake of Bonsmara bulls and heifers in backgrounding or pasture-based production systems (Ethical clearance number A16-SCI-AGR-001). Growth and intake data were collected from the Kromme Rhee Bonsmara stud in the Stellenbosch region. The growth curves of steers and heifers were modelled using the Gompertz function. Parameter estimates of the function showed that the mature weight (A) parameter was greater (P <0.05) for bulls than heifers (ca. 878.4 vs 562.1 kg, respectively). The maturation rates (parameter B) did not differ between the sexes, while the days at maximum growth (parameter C) was higher for bulls (291.5 days) than for heifers (182.4 days). Linear functions were used to describe the average feed intakes, as well as cumulative intakes, with body weights from growing bulls and heifers from the ages 6-20 months reared on lucerne hay and protein supplement. On average, it was observed that on the lucerne hay-based diet, Bonsmara bulls and heifers consumed about 2.43% of body weight daily throughout the study period. These models can be used in precision beef rearing systems to predict the production and market weights of Bonsmara calves that are either reared on hay or pasture.


2021 ◽  
Vol 923 (1) ◽  
pp. 012086
Author(s):  
Kadhm K.A. Alabdalsayid ◽  
Lamiaa M.S. Al-Freeh

Abstract A field experiment was conducted during the agricultural season 2020-2021 at the Agricultural Research Station/College of Agriculture/University of Basra (Al-Haritha site) (20 km from the center of Basra Governorate). To study the effect of four levels of phosphate fertilizer (P0=0, P1=50, P2=100 and P3=150 Kg ha-1) and four concentrations of iron spray(F0=0, F1=1000, F2=2000 and F3=3000 PPM). on the growth, yield and quality of oats (Avena sativa L.) Janzania cultivar the experiment was carried out in a split-plot arrangementusinga randomized complete block design (RCBD) with three replications. Phosphate fertilizer levels occupied the main plot, and iron concentrations occupied the sub-plots. The results showed that the P3 level was significantly superior in all the studied traits, which gave the highest grain yield of 6.13 mcg ha-0. The concentration F2 was significantly superior in all the studied traits, which gave the highest grain yield of 5.29 mcg ha-0. The interaction also showed the superiority of the combination P3*F2 in plant height, flag leaf area, number of branches and grain yield, while the interaction was not significant in the trait of leaf area index and Net Assimilation rate and crop growth rate


Author(s):  
Mahnaz Asghari ◽  
Ahmad Sheykhi

Abstract The thermodynamics-gravity conjecture reveals that one can derive the gravitational field equations by using the first law of thermodynamics and vice versa. Considering the entropy associated with the horizon in the form of non-extensive Tsallis entropy, S ∼ Aβ here we first derive the corresponding gravitational field equations by applying the Clausius relation δQ = TδS to the horizon. We then construct the Friedmann equations of Friedmann-Lemaître-Robertson-Walker (FLRW) universe based on Tsallis modified gravity (TMG). Moreover, in order to constrain the cosmological parameters of TMG model, we use observational data, including Planck cosmic microwave background (CMB), weak lensing, supernovae, baryon acoustic oscillations (BAO), and redshift-space distortions (RSD) data. Numerical results indicate that TMG model with a quintessential dark energy is more compatible with the low redshift measurements of large scale structures by predicting a lower value for the structure growth parameter σ8 with respect to ΛCDM model. This implies that TMG model would slightly alleviate the σ8 tension.


Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1201
Author(s):  
Mohamed Kayid

In contrast to many survival models such as proportional hazard rates and proportional mean residual lives, the proportional vitalities model has also been introduced in the literature. In this paper, further stochastic ordering properties of a dynamic version of the model with a random vitality growth parameter are investigated. Examples are presented to illustrate different established properties of the model. Potentials for inference about the parameters in proportional vitalities model with possibly time-varying effects are also argued and discussed.


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