2,584 research outputs found
The Influence of Colour on Radiometric Performances of Agricultural Nets
The whole construction parameters of the net, combined with the shape of the structure, the position of the sun and the sky conditions affect the radiometric performance of the permeable covering system. The radiometric properties of the permeable membrane influence the quality of the agricultural production and the aesthetic characteristics of the netting system. Moreover, the colour of the material and the light reflection- especially of the wavelengths visible for the human eye (VIS, 380-760nm)- is an interesting criterion to determine the aesthetic value of the net structure and its environmental impact. In order to investigate the influence of the threads colour on the radiometric properties of the net, a set of field tests were performed by means of a spectroradiometer in combination with an experimental setup 120x120x50cm covered with membranes formed by threads with different colour. A second set of experiments were performed, on the same kind of nets, in laboratory by means of a combination of a large integrating sphere and a small one: the transmissivity from a direct (tauDIR) and diffuse ((tauDIF) source and the reflectivity from diffuse source (Âż) of 50x50cm samples were measured in the PAR range. The evaluation of the transmissivity values shows that the colour of a net influence spectral distribution of the radiation passing through the net absorbing their complementary colours. The transmissivity of black nets is almost constant in the visible range and the reduction of the incoming radiation is proportional to the solidity of the net. In the PAR range transparent and black nets doesnÂżt cause an alteration of the spectrum of solar radiation and transmittance is almost constant with a slight growth in nets having lower porosity
Plastic nets in agriculture ; a general review of types and applications
At the moment, there are a large number of agricultural net types on the market characterized by different structural features such as type of material, type and dimensions of threads, texture, mesh size, porosity / solidity and weight; by radiometric properties like color, transmissivity/reflectivity/shading factor; by physical properties like air permeability and several mechanical characteristics such as tensile stress, strength, elongation at break, and durability. Protection from hail, wind, snow, or strong rainfall in fruit-farming and ornamentals, shading nets for greenhouses and nets moderately modifying the microenvironment for a crop are the most common applications. A systematic review of the current state-of-the-art of structural parameters, standard and regulations, most common agricultural net applications, and their supporting structures has been developed by means of a literature study, technical investigations, concerning characteristics and use of nets. As a result, the survey highlighted that in many cases different, not even similar, net types were adopted for the same application and the same cultivations by various growers. Results show that neither growers nor net producers have clear ideas about the relationship between the net typology optimization for a specific application and the construction parameters of the net. The choice often depends on empirical or economic criteria and not on scientific considerations. Moreover, it appears that scientifically justified technical requirements for nets used in specific agricultural applications have not been established yet
Floating s- and p-type Gaussian Orbitals
The advantages of including a small number of p-type gaussian functions in a floating spherical gaussian orbital calculation are pointed out and illustrated by calculations on molecules which previously have proved to be troublesome. These include molecules such as F2 with multiple lone pairs and C2H2 with multiple bonds. A feature of the results is the excellent correlation between the orbital energies and those of a double zeta calculation reported by Snyder and Basch
Root Zone Sensors for Irrigation Management in Intensive Agriculture
Crop irrigation uses more than 70% of the worldâs water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the growerâs experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZSâ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy
Prevention of serious respiratory syncytial virus-related illness. I: Disease pathogenesis and early attempts at prevention
A new direction for water management? Indigenous nation building as a strategy for river health
© 2017 by the author(s). Indigenous involvement in Australian water management is conventionally driven by a top-down approach by nonIndigenous government agencies, that asks âhow do we engage Indigenous people?â and has culminated in the ineffective âconsultâ and âservice deliveryâ processes evident in mainstream water management planning. This is a hopeful paper that identifies the critical importance of a ânation-basedâ approach for effective Indigenous engagement in water planning and policy through the work undertaken by the Ngarrindjeri Regional Authority (NRA) in the Murray Futures program. The NRA is an Indigenous government in the âsettled-southâ of Australia. Over past decades, the NRA has developed a range of political technologies that act as tools for redeveloping Ngarrindjeri Nationhood after colonial disempowerment and dispossession. These tools enable better collaboration with nonIndigenous governments, especially in natural resource management policy and practice. In turn, this has better enabled the NRA to exercise a decision-making and planning authority over the lands and waters in its jurisdiction, therefore, more effectively exercising its ongoing duty of care as Country. This paper presents a case study of the Sugar Shack Complex Management Plan, codeveloped by the NRA and the South Australian Government in 2015, to demonstrate the benefits that accrue when Indigenous nations are resourced as authorities responsible for reframing water management and planning approaches to facilitate the equitable collaboration of Indigenous and nonIndigenous worldviews. As a marker of the success of this strategy, the Ngarrindjeri Yarluwar-Ruwe Program, in partnership with the South Australian government, recently won the Australian Riverprize 2015 for delivering excellence in Australian river management
Mesh inlay, mesh kit or native tissue repair for women having repeat anterior or posterior prolapse surgery: randomised controlled trial (PROSPECT)
Funding The project was funded by the National Institute for Health Research Health Technology Assessment Programme (Project Number 07/60/18). The Health Services Research Unit and the Health Economics Research Unit are funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. Acknowledgements The authors wish to thank the women who participated in the PROSPECT study. We also thank Margaret MacNeil for her secretarial support and data management; Dawn McRae and Lynda Constable for their trial management support; the programming team in CHaRT, led by Gladys McPherson; members of the Project Management Group for their ongoing advice and support of the study; and the staff at the recruitment sites who facilitated the recruitment, treatment and follow up of study participants.Peer reviewedPublisher PD
Beyond the veil: Inner horizon instability and holography
We show that scalar perturbations of the eternal, rotating BTZ black hole
should lead to an instability of the inner (Cauchy) horizon, preserving strong
cosmic censorship. Because of backscattering from the geometry, plane wave
modes have a divergent stress tensor at the event horizon, but suitable
wavepackets avoid this difficulty, and are dominated at late times by
quasinormal behavior. The wavepackets have cuts in the complexified coordinate
plane that are controlled by requirements of continuity, single-valuedness and
positive energy. Due to a focusing effect, regular wavepackets nevertheless
have a divergent stress-energy at the inner horizon, signaling an instability.
This instability, which is localized behind the event horizon, is detected
holographically as a breakdown in the semiclassical computation of dual CFT
expectation values in which the analytic behavior of wavepackets in the
complexified coordinate plane plays an integral role. In the dual field theory,
this is interpreted as an encoding of physics behind the horizon in the
entanglement between otherwise independent CFTs.Comment: 40 pages, LaTeX, 3 eps figures, v2: references adde
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