scholarly journals A study regarding the parameters that influence the growth rate of Salix alba

2021 ◽  
Vol 3 (2) ◽  
pp. 78-88
Author(s):  
Gabriel Murariu ◽  
◽  
Raluca Enescu ◽  
Diana Vasile ◽  
Lucian Dinca ◽  
...  

The inventory and evaluation of growth rates for afforested surfaces is extremely important in estimating production levels and in determining the wood quantities that can be harvested. The present research was realized in southeast Romania, on a surface that contains 375h of afforested fields. The monitored surfaces are situated in Hanu-Conachi Independenta Forest, at a relatively low altitude. The study took into account only the surfaces afforested with willow (Salix alba) and extended between 2010 and 2015. The afforested surfaces’ consistency and age were evaluated based on direct observations and measurements. The used numerical analysis on different optimization methods was selected from amongst the most used series from the specialty literature. Our results have shown that evaluations of estimated production growth rates can vary significantly when different statistical analyses and numeric methods are used. By using numerical optimizing models, computer simulations can offer precise estimations regarding growth rates, and consequently, for the efficiency of a given forest inventory. Common numerical interpolation methods or the usage of neuronal networks do not always lead to consistent results. Specific numeric methods are preferable for a better evaluation of growth rates and current inventory. In addition, investments in computer simulation methods and software should be encouraged in order to reach a permanent inventory, improve the efficiency of exploitation operations, and sustain environmental protection.

The study explores the trends in the export of major fruits, namely, apple, banana, grapes, and mangoes from India during 1999- 2000 to 2017-18. The secondary data on area, production, export quantity, and export value were collected from APEDA and NHB to achieve the objectives of the study. The data were analysed using the tools such as percentages, compound growth rates, and Cuddy- Della Valle instability index. The results indicated that selected fruits form 62.79 percent share of the total world fruit area and 72.41 percent share of total fruit production of the World. Although India has a vast production base yet, it exports less than one percent share of the production of major fruits like apple, banana, and grapes. However, the share of export in mango production is quite promising. The growth rates in the production of selected fruits were positive and higher than the growth rate of production of the world. Interestingly, the fruits with high production growth, such as bananas and grapes, had stable exports, whereas apple and mango showed moderate production growth and high volatility in exports.


2020 ◽  
Vol 16 (7) ◽  
pp. 1297-1316
Author(s):  
O.N. Terent'eva

Subject. The stable supply of food to people is a cornerstone for the national economic security, while a lack of food or its expensiveness may undermine the economy, principles of power, and cause panics and wars. Malnutrition and hunger are critical indicators of the insufficient foods supply. Objectives. The article indicates which countries have high risk of hunger, and predicts its further movement. I also evaluate factual trends in the availability of food across countries. Methods. The study refers to statistical data in public domain, including the FAOSTAT. I apply methods of ranking, abstraction, prediction. Results. I performed the cross-country analysis and discovered that 117 countries demonstrated signs of malnutrition. The article sets forth a technique for splitting countries into five groups by level of hunger risk. The article compares data on hunger in the countries and consequences of mortality and morbidity. I ranked countries by key types of agricultural products and explained their production growth rates for a span of 18 years. I predicted how countries would be ranked in terms of hunger from 2030 to 2050, and found the extent to which the hunger risk will escalate in more flourishing countries. Conclusions and Relevance. Hunger and shortage of food seem invincible in the countries where people are hungry or very hungry. Sometimes it appears almost impossible for respective governments to solve the issue. Triggering the systemic hunger, such factors and premises are beyond control of starving countries. Hence, the international community should provide their support and aid to them.


1990 ◽  
Vol 55 (7) ◽  
pp. 1691-1707 ◽  
Author(s):  
Miloslav Karel ◽  
Jiří Hostomský ◽  
Jaroslav Nývlt ◽  
Axel König

Crystal growth rates of copper sulphate pentahydrate (CuSO4.5 H2O) determined by different authors and methods are compared. The methods included in this comparison are: (i) Measurement on a fixed crystal suspended in a streaming solution, (ii) measurement on a rotating disc, (iii) measurement in a fluidized bed, (iv) measurement in an agitated suspension. The comparison involves critical estimation of the supersaturation used in measurements, of shape factors used for data treatment and a correction for the effect of temperature. Conclusions are drawn for the choice of values to be specified when data of crystal growth rate measurements are published.


1989 ◽  
Vol 54 (11) ◽  
pp. 2951-2961 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.


2021 ◽  
pp. 0272989X2110222
Author(s):  
Yuwen Gu ◽  
Elise DeDoncker ◽  
Richard VanEnk ◽  
Rajib Paul ◽  
Susan Peters ◽  
...  

It is long perceived that the more data collection, the more knowledge emerges about the real disease progression. During emergencies like the H1N1 and the severe acute respiratory syndrome coronavirus 2 pandemics, public health surveillance requested increased testing to address the exacerbated demand. However, it is currently unknown how accurately surveillance portrays disease progression through incidence and confirmed case trends. State surveillance, unlike commercial testing, can process specimens based on the upcoming demand (e.g., with testing restrictions). Hence, proper assessment of accuracy may lead to improvements for a robust infrastructure. Using the H1N1 pandemic experience, we developed a simulation that models the true unobserved influenza incidence trend in the State of Michigan, as well as trends observed at different data collection points of the surveillance system. We calculated the growth rate, or speed at which each trend increases during the pandemic growth phase, and we performed statistical experiments to assess the biases (or differences) between growth rates of unobserved and observed trends. We highlight the following results: 1) emergency-driven high-risk perception increases reporting, which leads to reduction of biases in the growth rates; 2) the best predicted growth rates are those estimated from the trend of specimens submitted to the surveillance point that receives reports from a variety of health care providers; and 3) under several criteria to queue specimens for viral subtyping with limited capacity, the best-performing criterion was to queue first-come, first-serve restricted to specimens with higher hospitalization risk. Under this criterion, the lab released capacity to subtype specimens for each day in the trend, which reduced the growth rate bias the most compared to other queuing criteria. Future research should investigate additional restrictions to the queue.


Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 187
Author(s):  
Rolf Vieten ◽  
Francisco Hernandez

Speleothems are one of the few archives which allow us to reconstruct the terrestrial paleoclimate and help us to understand the important climate dynamics in inhabited regions of our planet. Their time of growth can be precisely dated by radiometric techniques, but unfortunately seasonal radiometric dating resolution is so far not feasible. Numerous cave environmental monitoring studies show evidence for significant seasonal variations in parameters influencing carbonate deposition (calcium-ion concentration, cave air pCO2, drip rate and temperature). Variations in speleothem deposition rates need to be known in order to correctly decipher the climate signal stored in the speleothem archive. StalGrowth is the first software to quantify growth rates based on cave monitoring results, detect growth seasonality and estimate the seasonal growth bias. It quickly plots the predicted speleothem growth rate together with the influencing cave environmental parameters to identify which parameter(s) cause changes in speleothem growth rate, and it can also identify periods of no growth. This new program has been applied to multiannual cave monitoring studies in Austria, Gibraltar, Puerto Rico and Texas, and it has identified two cases of seasonal varying speleothem growth.


Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Maria N. Metsoviti ◽  
George Papapolymerou ◽  
Ioannis T. Karapanagiotidis ◽  
Nikolaos Katsoulas

In this research, the effect of solar irradiance on Chlorella vulgaris cultivated in open bioreactors under greenhouse conditions was investigated, as well as of ratio of light intensity in the 420–520 nm range to light in the 580–680 nm range (I420–520/I580–680) and of artificial irradiation provided by red and white LED lamps in a closed flat plate laboratory bioreactor on the growth rate and composition. The increase in solar irradiance led to faster growth rates (μexp) of C. vulgaris under both environmental conditions studied in the greenhouse (in June up to 0.33 d−1 and in September up to 0.29 d−1) and higher lipid content in microalgal biomass (in June up to 25.6% and in September up to 24.7%). In the experiments conducted in the closed bioreactor, as the ratio I420–520/I580–680 increased, the specific growth rate and the biomass, protein and lipid productivities increased as well. Additionally, the increase in light intensity with red and white LED lamps resulted in faster growth rates (the μexp increased up to 0.36 d−1) and higher lipid content (up to 22.2%), while the protein, fiber, ash and moisture content remained relatively constant. Overall, the trend in biomass, lipid, and protein productivities as a function of light intensity was similar in the two systems (greenhouse and bioreactor).


1974 ◽  
Vol 11 (03) ◽  
pp. 437-444 ◽  
Author(s):  
Benoit Mandelbrot

Luria and Delbrück (1943) have observed that, in old cultures of bacteria that have mutated at random, the distribution of the number of mutants is extremely long-tailed. In this note, this distribution will be derived (for the first time) exactly and explicitly. The rates of mutation will be allowed to be either positive or infinitesimal, and the rate of growth for mutants will be allowed to be either equal, greater or smaller than for non-mutants. Under the realistic limit condition of a very low mutation rate, the number of mutants is shown to be a stable-Lévy (sometimes called “Pareto Lévy”) random variable, of maximum skewness ß, whose exponent α is essentially the ratio of the growth rates of non-mutants and of mutants. Thus, the probability of the number of mutants exceeding the very large value m is proportional to m –α–1 (a behavior sometimes referred to as “asymptotically Paretian” or “hyperbolic”). The unequal growth rate cases α ≠ 1 are solved for the first time. In the α = 1 case, a result of Lea and Coulson is rederived, interpreted, and generalized. Various paradoxes involving divergent moments that were encountered in earlier approaches are either absent or fully explainable. The mathematical techniques used being standard, they will not be described in detail, so this note will be primarily a collection of results. However, the justification for deriving them lies in their use in biology, and the mathematically unexperienced biologists may be unfamiliar with the tools used. They may wish for more details of calculations, more explanations and Figures. To satisfy their needs, a report available from the author upon request has been prepared. It will be referred to as Part II.


1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.


1994 ◽  
Vol 274 ◽  
pp. 219-241 ◽  
Author(s):  
R. R. Kerswell

We examine the possibility that the Earth's outer core, as a tidally distorted fluid-filled rotating spheroid, may be the seat of an elliptical instability. The instability mechanism is described within the framework of a simple Earth-like model. The preferred forms of wave disturbance are explored and a likely growth rate supremum deduced. Estimates are made of the Ohmic and viscous decay rates of such hydromagnetic waves in the outer core. Rather than a conclusive disparity of scales, we find that typical elliptical growth rates, Ohmic decay rates and viscous decay rates all have the same order for plausible core fields and core-to-mantle conductivities. This study is all the more timely considering the recent realization that the Earth's precession may also drive similar instabilities at comparable strengths in the outer core.


Sign in / Sign up

Export Citation Format

Share Document