一种面向育种家的新型台式棉籽脱绒机

正棉籽酸脱绒会危害育种家人身安全和潜在环境。需要1种无需用酸,能有效去除棉短绒且对棉种萌发无不利影响的脱绒方法。为了优化棉籽机械脱绒流程,美国农业部农业研究中心(USDA-ARS)棉花生产与加工部门(Lubbock,Texas)研发创制了一台棉籽机械脱绒样机(图1,图2)。测试设计了应用7种滚筒衬垫(1种是不用任何研磨材料,其余6种分别采用不同的研磨材料)、1个或2个辊刷"擦     

Quantification of flight times of aerial treatments targeting invasive species: the interplay of helicopter or drone with bait-delivery systems,flight speed and bait form

BACKGROUND

Aerial treatments for invasive species management are now common, but we are unaware of any work published in the scientific literature quantifying how the interplay of numerous factors affects flight time and therefore operational costs. Here, we analyse aerial treatment data collected from two ant-eradication programmes, quantifying how the relationships between flight time and area are influenced by numerous aircraft/delivery system/bait/flight speed combinations.

RESULTS

For bait dispersal by helicopters, and when swath widths are equivalent, side-mounted Isolair was significantly more efficient than the simultaneous use of two underslung buckets, and use of two buckets was slightly but not significantly more efficient than one bucket. In this scenario, delivery by Isolair was, on average, 39.8% and 31.5% more efficient than the use of one or two buckets, respectively. However, when the swath width used with Isolair was halved to 10 m and flight speed was increased slightly, flight time was significantly greater compared to the other configurations. For bait dispersed by drone, flights conducted using an upgraded Flight Management System (FMS) and greater flight speed but smaller swath width were significantly more efficient than flights using the older FMS and lower flight speed. Over 10 and 50 ha the helicopter was 2.87 and 4.82 times more time efficient than the drone.

CONCLUSION

We encourage practitioners to publish data from their aerial treatments, and to try new methods, to accelerate improvements in efficiency and reduce the costs of aerial treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Conceptus elongation in ruminants: roles of progesterone,prostaglandin, interferon tau and cortisol

The majority of pregnancy loss in ruminants occurs during the first three weeks after conception, particularly during the period of conceptus elongation that occurs prior to pregnancy recognition and implantation. This review integrates established and new information on the biological role of ovarian progesterone(P4), prostaglandins(PGs),interferon tau(IFNT) and cortisol in endometrial function and conceptus elongation. Progesterone is secreted by the ovarian corpus luteum(CL) and is the unequivocal hormone of pregnancy. Prostaglandins(PGs) and cortisol are produced by both the epithelial cells of the endometrium and the trophectoderm of the elongating conceptus. In contrast, IFNT is produced solely by the conceptus trophectoderm and is the maternal recognition of pregnancy signal that inhibits production of luteolytic pulses of PGF2αby the endometrium to maintain the CL and thus production of P4. Available results in sheep support the idea that the individual, interactive, and coordinated actions of P4, PGs, IFNT and cortisol regulate conceptus elongation and implantation by controlling expression of genes in the endometrium and/or trophectoderm. An increased knowledge of conceptus-endometrial interactions during early pregnancy in ruminants is necessary to understand and elucidate the causes of infertility and recurrent early pregnancy loss and provide new strategies to improve fertility and thus reproductive efficiency.     

Evaluating the effect of 3D urban form on neighborhood land surface temperature using Google Street View and geographically weighted regression

Landscape Ecology - Land surface temperature (LST) directly responds to incoming solar radiation and is strongly influenced by vertical urban structures, such as trees and buildings that provide...     

The homogenizing influence of agriculture on forest bird communities at landscape scales

Landscape Ecology - Agricultural expansion is a principal driver of biodiversity loss, but the impacts on community assembly in agro-ecosystems are less clear, especially across regional scales at...     

Do lethal trap devices threaten foot-hold trap capture efficacy?

Foot-hold trapping is an important tool used in pest management programs in countries such as Australia, New Zealand and in North America. Research on humane trapping methods including the addition of sedatives (Tranquilizer Trap Device) and toxins (Lethal Trap Device) to foot-hold traps to improve the welfare of trapped pest animals is important. Lethal Trap Devices (LTD) are being tested in Australia to determine if deploying a toxin with a foot-hold trap is effective at delivering a lethal dose of toxin to trapped predators. This study aimed to test whether fitting an LTD to two different foot-hold jaw traps (Victor Soft catch #3 and Bridger #5) would affect the jaw closure time and as such affect capture rates. We found that two spring Victor Soft catch traps were faster (20.91, SD 0.72 ms) than four spring Bridger #5 traps (26.79, SD 0.48 ms) even when fitted with a Lethal Trap Device. Fitting a Lethal Trap Device to either of these trap models did not affect closure time and as such would not have any effect on capture efficacy.     

Landscape dynamics of floral resources affect the supply of a biodiversity-dependent cultural ecosystem service

Context

Cultural ecosystem services, many of which depend on biodiversity, are recognized as important but seldom quantified biophysically across landscapes. Furthermore, many ecosystem service models are static, and the supply of cultural ecosystem services may be misrepresented if seasonal shifts in biotic communities are ignored.

Objectives

We modeled landscape dynamics of wildflower blooms in a temperate montane landscape to determine (1) how floral resources (wildflower species richness, abundance, timing, and presence of charismatic species) changed over the growing season, (2) how projected wildflower viewing hotspots varied over space and time, and (3) how spatial shifts in floral resources affected potential public access to wildflower viewing.

Methods

Data were collected at 63 sites across a rural-to-urban gradient in the Southern Appalachian Mountains (USA). Generalized linear models were used to identify factors affecting floral resources at two temporal scales. Floral resources were projected across the landscape and hotspots of wildflower viewing were quantified using overlay analysis.

Results

Floral resources were affected by topoedaphic conditions, climate, and surrounding building density and changed seasonally. Seasonal models revealed locational shifts in ecosystem service hotspots, which changed the proportion of hotspots accessible to the public and identified wildflower-viewing opportunities unnoticed by static models.

Conclusion

Relationships between landscape gradients, biodiversity, and ecosystem service supply varied seasonally, and our models identified cultural ecosystem service hotspots otherwise obscured by simple proxies. Landscape models of biodiversity-based cultural ecosystem services should include seasonal dynamics of biotic communities to avoid under- or over-emphasizing the importance of particular locations in ecosystem service assessments.

     

Reproductive resilience: a paradigm shift in understanding spawner‐recruit systems in exploited marine fish

A close relationship between adult abundance and stock productivity may not exist for many marine fish stocks, resulting in concern that the management goal of maximum sustainable yield is either inefficient or risky. Although reproductive success is tightly coupled with adult abundance and fecundity in many terrestrial animals, in exploited marine fish where and when fish spawn and consequent dispersal dynamics may have a greater impact. Here, we propose an eco‐evolutionary perspective, reproductive resilience, to understand connectivity and productivity in marine fish. Reproductive resilience is the capacity of a population to maintain the reproductive success needed to result in long‐term population stability despite disturbances. A stock's reproductive resilience is driven by the underlying traits in its spawner‐recruit system, selected for over evolutionary timescales, and the ecological context within which it is operating. Spawner‐recruit systems are species specific, have both density‐dependent and fitness feedback loops and are made up of fixed, behavioural and ecologically variable traits. They operate over multiple temporal, spatial and biological scales, with trait diversity affecting reproductive resilience at both the population and individual (i.e. portfolio) scales. Models of spawner‐recruit systems fall within three categories: (i) two‐dimensional models (i.e. spawner and recruit); (ii) process‐based biophysical dispersal models which integrate physical and environmental processes into understanding recruitment; and (iii) complex spatially explicit integrated life cycle models. We review these models and their underlying assumptions about reproductive success vs. our emerging mechanistic understanding. We conclude with practical guidelines for integrating reproductive resilience into assessments of population connectivity and stock productivity.     

Genotypic Variation for Tolerance to Transient Drought During the Reproductive Phase of Brassica rapa

Brassica rapa L. is a genetically diverse parent species of the allotetraploid species, oilseed rape (B. napus) and a potential source of drought tolerance for B. napus. We examined the effect of a 13‐day drought stress period during the early reproductive phase, relative to a well‐watered (WW) control, on subsequent growth and development in nine accessions of B. rapa and one accession of Brassica juncea selected for their wide morphological and genetic diversity. We measured leaf water potential, stomatal conductance, water use, and leaf and bud temperatures during the stress period and aboveground dry weight of total biomass at maturity. Dry weight of seeds and reproductive tissue were not useful measures of drought tolerance due to self‐incompatibility in B. rapa. The relative total biomass (used as the measure of drought tolerance in this study) of the 10 accessions exposed to drought stress ranged from 47 % to 117 % of the WW treatment and was negatively correlated with leaf‐to‐air and bud‐to‐air temperature difference when averaged across the 13‐day stress period. Two wild‐type (B. rapa ssp. sylvestris) accessions had higher relative total and non‐reproductive biomass at maturity and cooler leaves and buds than other types. We conclude that considerable genotypic variation for drought tolerance exists in B. rapa and cooler leaves and buds during a transient drought stress in the early reproductive phase may be a useful screening tool for drought tolerance.