Cucurbit yellow stunting disorder virus.

Author(s):  
Dirk Janssen

Abstract Cucurbit yellow stunting disorder virus (CYSDV) is a crinivirus that is non-circulative, semi-persistently transmitted by the whitefly Bemisia tabaci. It multiplies in cucurbitaceous plant species but not inside its insect vector. The main pathways of CYSDV introduction and long-distance spread are through infected plants for planting. Short-distance spread is predominantly through viruliferous (infected) adults of B. tabaci. CYSDV is considered an 'emerging virus' and is increasingly recorded from a number of European, American and Asiatic countries. Infected cucurbit crops display yellowing symptoms on the leaves and this damage leads to an approximate yield reduction of 30-50% in Spain and Lebanon (Célix et al., 1996; Hourani and Abou-Jawdah, 2003). In Arizona, the outbreak of CYSDV in 2006 caused an estimated 60% reduction in marketable melon yield and a subsequent US$ 18 million loss (McGinley, 2008; James, 2011). CYSDV was added to the EPPO A2 List in 2004.

2020 ◽  
Author(s):  
Jelle Treep ◽  
Monique de Jager ◽  
Frederic Bartumeus ◽  
Merel B. Soons

Abstract Background – Plant dispersal is a critical factor driving ecological responses to global changes. Knowledge on the mechanisms of dispersal is rapidly advancing, but selective pressures responsible for the evolution of dispersal strategies remain elusive. Recent advances in animal movement ecology identified general strategies that may optimize efficiency in animal searches for food or habitat. We here explore the potential for evolution of similar general movement strategies for plants.Methods – We propose that seed dispersal in plants can be viewed as a strategic search for suitable habitat, where the probability of finding such locations has been optimized through evolution of appropriate dispersal kernels. Using model simulations, we demonstrate how dispersal strategies can optimize key dispersal trade-offs between finding habitat, avoiding kin competition, and colonizing new patches. These trade-offs depend strongly on the landscape, resulting in a tight link between optimal dispersal strategy and spatiotemporal habitat distribution.Results – Our findings reveal that multi-scale seed dispersal strategies that combine short-distance and long-distance dispersal, including Lévy-like dispersal, are optimal across a wide range of dynamic and patchy landscapes. Static patchy landscapes select for short-distance dominated dispersal strategies, while uniform and highly unpredictable landscapes both select for long-distance dominated dispersal strategies.Conclusions – By viewing plant seed dispersal as a strategic search for suitable habitat, we provide a reference framework for the analysis of plant dispersal data. This reference framework helps identify plant species’ dispersal strategies, the evolutionary forces determining these strategies and their ecological consequences, such as a potential mismatch between plant dispersal strategy and altered spatiotemporal habitat dynamics due to land use change. Our perspective opens up directions for future studies, including exploration of composite search behaviour and ‘informed searches’ in plant species with directed dispersal.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Avital Dery ◽  
Mitrajyoti Ghosh ◽  
Yuval Grossman ◽  
Stefan Schacht

Abstract The K → μ+μ− decay is often considered to be uninformative of fundamental theory parameters since the decay is polluted by long-distance hadronic effects. We demonstrate that, using very mild assumptions and utilizing time-dependent interference effects, ℬ(KS → μ+μ−)ℓ=0 can be experimentally determined without the need to separate the ℓ = 0 and ℓ = 1 final states. This quantity is very clean theoretically and can be used to test the Standard Model. In particular, it can be used to extract the CKM matrix element combination $$ \mid {V}_{ts}{V}_{td}\sin \left(\beta +{\beta}_s\right)\mid \approx \mid {A}^2{\lambda}^5\overline{\eta}\mid $$ ∣ V ts V td sin β + β s ∣ ≈ ∣ A 2 λ 5 η ¯ ∣ with hadronic uncertainties below 1%.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Nathalie Becker ◽  
Loup Rimbaud ◽  
Frédéric Chiroleu ◽  
Bernard Reynaud ◽  
Gaël Thébaud ◽  
...  

2021 ◽  
Vol 11 (6) ◽  
pp. 109-119
Author(s):  
Q. Ramabaja ◽  
N. Rashiti ◽  
M. Shkodra ◽  
L. Ramadani

The knowledge of morphological development and their impact on motor skills in short-distance athletes should be one of the main concerns of athletics coaches, because any scientific research in the field of physical culture and sports is about proving the development and evaluation of anthropological characteristics which are responsible for achieving success in athletics. The purpose of this paper is to confirm the impact of some anthropometric characteristics in the execution of running speeds on short distances, specifically in running at 100, 200 and 400 meters to students aged 18 ± 6 years of the Faculty of Physical Education and Sports in Prishtina. The sample of this research has included a total of 60 students aged 18 years of the Faculty of Physical Education and Sports in Prishtina. The measurements were executed during September in the hall of the Faculty, while the 100, 200, and 400 meter runs in the stadium "Fadil Vokrri" Prishtina. The only condition that was used during the determination of the sample was: that the students are involved in regular physical education classes (and on the day of the measurement be healthy, without the flu, cold or other symptoms). The variables which are applied in this research have been 8 anthropometric variables and 3 motor-specific variables. The results obtained after their processing indicate that the impact of anthropometric variables is higher in running at 100, 200 and 400 meters. Short distance running and long distance running reduces the impact of anthropometric parameters whereas the influence of metabolic factors of energy production is increased.  These results were also confirmed using regression analysis, so that groups of predictors of anthropometric characteristics, specific motor skills that statistically significantly influenced each variable of individual criteria. The world records below the 10-second limit, in the 100 m, near the 9-meter limit, show not only the high level of sports, but also the strong impact on the growth, especially of strength indicators, speed-strength, explosive force, as main and applied motor skills in sports and athlete’s everyday life.


2019 ◽  
Vol 11 (23) ◽  
pp. 6696 ◽  
Author(s):  
Cai ◽  
Liu ◽  
Luo ◽  
Xing ◽  
Liu

Jobs–housing imbalance is a hot topic in urban study and has obtained many results. However, little research has overcome the limits of administrative boundaries in job accessibility measurement and considered differences in job accessibility within multiple commuting circles. Using Baidu location data, this research proposes a new method to measure job accessibility within multiple commuting circles at the grids’ level. Taking the Wuhan metropolitan area as a case study, the results are as follows: (1) Housing and service jobs are concentrated in the central urban areas along the Yangtze River, whereas industrial jobs are scattered throughout suburbs with double centers. The potential competition for job opportunities is fiercer in the city center than in the suburbs. (2) Job accessibility with different levels shows significant circle-like distribution. People with long- or short-distance potential commutes demand to live close to the groups with the same demand. Residents with long-distance commutes demand to live outside of where those with short-distance commutes demand to reside, regardless of whether their commuting demand is for service or industrial jobs. (3) There are three optimization patterns for transit services to increase job accessibility in various areas. These patterns involve areas with inadequate job opportunities, poor transit services to service jobs, and poor transit services to industrial jobs. Developing current transit facilities or new transit alternatives as well as adding extra jobs near housing could improve jobs–housing imbalance in these areas. Findings from this study could guide the allocation of jobs and housing as well as the development of transport to reduce residents’ commuting burdens and promote transportation equity. The method used in this study can be applied to evaluate jobs–housing imbalance from the perspective of the supply in other metropolises.


2020 ◽  
Vol 10 (10) ◽  
Author(s):  
Jia Wang ◽  
Xiaomin Wang ◽  
Xuelai Wang ◽  
Huiying Zhang ◽  
Yong Zhou ◽  
...  

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