Economic implications of a virus prevention program in deciduous tree fruits in the US

Viral diseases in fruit trees present a potential danger that could injure the fruit industry, the planting stock industry (nurseries), and consumers in the United States and abroad. Currently, the US has a virus protection program (VPP) that serves to minimize the spread of viral diseases. This paper reports research estimating the economic consequences of the loss of the program on nurseries, growers and consumers. The potential economic losses are a measure of the value of the existing program. The paper focuses on apples, sweet cherries, and Clingstone peaches.

The effects of a loss of a VPP on nurseries would include direct and indirect losses from viral diseases in the form of lower quantity and quality of planting stocks. Fruit growers would be affected by reduced plant growth and fruit yield. Consumers would be affected by higher prices and reduced quantity of fruit.

We measured benefits of the virus prevention program as changes in consumer and producer surpluses. Empirical estimates were made using the method of avoided losses. Benefit estimates to three economic sectors—nurseries (avoided change in producer surplus), producers (avoided change in consumer and producer surpluses), and consumers (avoided change in consumer surplus)—were calculated. Total benefits for all three sectors were approximately $227.4 million a year, or more than 420 times the cost of the program. Our analysis utilizes a method that might be used to evaluate other programs that prevent the introduction of plant diseases.     

The zebrafish cationic amino acid transporter/glycoprotein-associated family: sequence and spatiotemporal distribution during development of the transport system b0,+ (slc3a1/slc7a9)

Fish Physiology and Biochemistry - System b0,+ absorbs lysine, arginine, ornithine, and cystine, as well as some (large) neutral amino acids in the mammalian kidney and intestine. It is a...     

Birds as seed dispersers in deser ts: suggestions from the ground-jays

The study of seed dispersal, biotic seed dispersal, and even less, the role of birds in it, have been almost neglected in deserts. Virtually absent from the lit...     

Mucor Species in Orchard Soil – Population Dynamics and Pathogenicity on Pear Fruit

Strains of Mucor piriformis were isolated from orchard soils and from packinghouse dump-tank waters. Pathogen propagules were not found in fruit sample washings. M. piriformis was the most prevalent of the Mucor isolates, only one of 67 isolates was a different Mucor sp., possibly M. racemosus. The population of the pathogen propagules fluctuated in an annual cyclic pattern, declining in warm months and increasing after harvest. The viability of sporangiospores was markedly affected by rain. There was a good correlation (r=0.88) between the number of recovered propagules in the soil and the amount of rainfall. M. piriformis isolates caused decay on pear at 0°C after 14 days.     

Changes in foliar carbon isotope composition and seasonal stomatal conductance reveal adaptive traits in Mediterranean coppices affected by drought

We estimated water-use efficiency and potential photosynthetic assimilation of Holm oak(Quercus ilex L.) on slopes of NW and SW aspects in a replicated field test examining the effects of intensifying drought in two Mediterranean coppice forests. We used standard techniques for quantifying gas exchange and carbon isotopes in leaves and analyzed total chlorophyll, carotenoids and nitrogen in leaves collected from Mediterranean forests managed under the coppice system. We postulated that responses to drought of coppiced trees would lead to differential responses in physiological traits and that these traits could be used by foresters to adapt to predicted warming and drying in the Mediterranean area. We observed physiological responses of the coppiced trees that suggested acclimation in photosynthetic potential and water-use efficiency:(1) a significant reduction in stomatal conductance(p0.01) wasrecorded as the drought increased at the SW site;(2) foliar δ13C increased as drought increased at the SW site(p0.01);(3) variations in levels of carotenoids and foliar nitrogen, and differences in foliar morphology were recorded, and were tentatively attributed to variation in photosynthetic assimilation between sites. These findings increase knowledge of the capacity for acclimation of managed forests in the Mediterranean region of Europe.     

白尾地鸦(Podoces hendersoni)的地理分布(英文)

本刊近期发表的文章认为中国本土的白尾地鸦(Podoces hendersoni)有东扩至青海及甘肃的趋势,然而文章忽略了一点:早期文献认为至少在 19 世纪该鸟种就已经存在于甘肃。白尾地鸦所依赖的浅地下水湿生植物很可能限制了其分布范围。因此,虽然当前全球气候变暖所引发的沙漠地域扩张,使得白尾地鸦的分布范围扩大,但它们可能只集中在植被保护较好的地区。然而,此类比较适合白尾地鸦生存的地区,目前正被黑尾地鸦(P.hendersoni)栖息利用。对这些地区进行深入研究,将更利于了解这两种相互排斥的鸟类。     

Multiple functions of buffer strips in farming areas

Buffer strips (BSs) are strips interposed between fields and streams that intercept and treat the waters leaving cropland, and so are a useful tool for reducing agricultural diffuse pollution in lowland areas. If properly vegetated and managed, they can also produce wood for burning, act as sinks for atmospheric CO₂ and enhance the landscape beauty.The paper presents an analysis of the different functions of BS and reviews the more important data from research programmes conducted over the last decade in Veneto Region (North-East Italy). Over a period of 3–5 years, in two experimental sites, young BS reduced total runoff by 33%, losses of N by 44% and P by 50% compared to no-BS. A mature BS was able to abate both NO₃–N and dissolved phosphorus concentrations by almost 100%, in most cases having exiting water that satisfied the limit for avoiding eutrophication. The BS also proved to be a useful barrier for herbicides, with concentrations abated by 60% and 90%, depending on the chemical and the time elapsed since application. Considering the CO₂ immobilized in the wood and soil together, the different BS monitored stored up to 80 t ha^?1 year^?1.The BS caused negligible disturbance to maize, soybean and sugarbeet yields. The hedgerows, particularly if composed of trees taller than 6 m, positively influenced the aesthetic value of the territory, improving its perceived naturalness and screening the man-made elements.Lastly, through a multi-objective analysis, opportunity costs were estimated to support the public decision-maker in determining the subsidies to be paid to encourage farmers to plant BS.     

Sulphur Isotopes, Trace Elements and Mineral Stability Diagrams of Waters from the Abandoned Fe–Cu Mines of Libiola and Vigonzano (Northern Apennines, Italy)

The geochemical characteristics of rills draining pyrite-chalcopyrite tailings impoundments and of bordering streams were investigated at the ophiolite-hosted Libiola and Vigonzano abandoned massive sulphide mines, northern Apennines Italy. Water samples were analysed for major and trace chemical composition, hydrogen and oxygen isotope composition, and sulphur isotope composition of aqueous sulphate. Sulphur isotope composition was determined also for some samples of ore sulphides. At Libiola, the newly acquired chemical results on waters corroborate those from previous investigations, thus providing additional support to existing geochemical models in terms of metal distribution, solid phases precipitation, reaction path modelling and mixing reaction paths, and environmental problems. At Vigonzano, the chemical characteristics of waters are similar to those at Libiola. In both localities, solution-secondary phase equilibria estimated using an updated thermodynamic dataset account for mineralogy in the field, including poorly crystalline phases like jurbanite and hydrowoodwardite. The hydrogen and oxygen isotope composition of waters at Libiola and Vigonzano agrees with their meteoric origin. Acid to neutral mine waters do not show any significant isotope shift with respect to the initial water, in spite of the oxidation of even large amounts of pyrite/chalcopyrite ore. The sulphur isotope composition of aqueous sulphate in mine rills at Libiola (δ ³⁴S?=?5.6 to 8.5‰; mean 6.5‰) matches that of massive sulphide ore (δ ³⁴S?=??0.5 to 6.7‰; mean 5.8‰), in keeping with the supergenic origin of the sulphate and related isotope effects in the sulphide oxidation process. Sulphate in mine waters at Vigonzano displays lower δ ³⁴S values in the range 0.6 to 1.5‰. The δ ³⁴S signature of massive ore specimens is within the range reported for most volcanic-hosted massive sulphide deposits, including Cyprus-type deposits.