38 research outputs found
AN IRRIGATION MODEL FOR MANAGEMENT OF LIMITED WATER SUPPLIES
A two-stage simulation/mathematical programming model is presented for determining the optimal intraseasonal allocation of irrigation water under conditions of limited water supply. The model is applied to a series of water shortage scenarios under both surface and center pivot irrigation. Economically efficient irrigation management is shown to involve the coordination of a number of managerial decisions, including irrigation scheduling, crop substitution, the adoption of improved irrigation labor practices, and idling land. The results indicate that significant opportunities exist for conserving water in the study area under both surface and center pivot irrigation.Crop Production/Industries, Resource /Energy Economics and Policy,
Hydrology of a claypan watershed
Digitized 2007 AES MoU.Includes bibliographical references (pages 42-43)
Combined Cisplatinum and Laser Thermal Therapy for Palliation of Recurrent Head and Neck Tumors
In recent years endoscopically controlled laser-induced thermal therapy (LITT) has been
increasingly accepted as a minimally invasive method for palliation of advanced or recurrent
head and neck or gastrointestinal cancer. Previous studies have shown that adjuvant
chemotherapy can potentiate endoscopic laser thermal ablation of obstructing tumors leading
to improved palliation in advanced cancer patients. Eight patients with recurrent head and
neck tumors volunteered to enroll as part of an ongoing phase II LITT clinical trial, and also
elected to be treated with systemic chemotherapy (cisplatin, 80 mg/m2) followed 24 h later by
palliative laser thermal ablation. Laser treatments were repeated in patients with residual
disease or recurrence for a total of 27 LITT sessions. Four of the 8 patients treated with laser
thermal chemotherapy remained alive after a median follow-up of 12 months. Of the 12 tumor
sites treated, complete responses were located in the oral cavity (3), oropharynx (1),
hypopharynx (1), maxillary sinus (1), and median survival for these patients was 9.5 months.
This initial experience with cisplatinum-based laser chemotherapy indicates both safety and
therapeutic potential for palliation of advanced head and neck cancer but this must be confirmed
by longer follow-up in a larger cohort of patients
Com o diabo no corpo: os terrĂveis papagaios do Brasil colĂŽnia
Desde a Antiguidade, papagaios, periquitos e afins (Psittacidae) fascinaram os europeus por seu vivo colorido e uma notĂĄvel capacidade de interação com seres humanos. A descoberta do Novo Mundo nada faria alĂ©m de acrescentar novos elementos ao trĂĄfico de animais exĂłticos hĂĄ muito estabelecido pelos europeus com a Ăfrica e o Oriente. Sem possuir grandes mamĂferos, a AmĂ©rica tropical participaria desse comĂ©rcio com o que tinha de mais atrativo, essencialmente felinos, primatas e aves - em particular os papagaios, os quais eram embarcados em bom nĂșmero. Contudo, a julgar pelos documentos do Brasil colĂŽnia, esses volĂĄteis podiam inspirar muito pouca simpatia, pois nenhum outro animal - exceto as formigas - foi tantas vezes mencionado como praga para a agricultura. AlĂ©m disso, alguns psitĂĄcidas mostravam-se tĂŁo loquazes que inspiravam a sĂ©ria desconfiança de serem animais demonĂacos ou possessos, pois sĂł trĂȘs classes de entidades - anjos, homens e demĂŽnios - possuĂam o dom da palavra. Nos dias de hoje, vĂĄrios representantes dos Psittacidae ainda constituem uma ameaça para a agricultura, enquanto os indivĂduos muito faladores continuam despertando a suspeita de estarem possuĂdos pelo demĂŽnio. Transcendendo a mera curiosidade, essa crença exemplifica o quĂŁo intrincadas podem ser as relaçÔes do homem com o chamado âmundo naturalâ, revelando um universo mais amplo e multifacetado do que se poderia supor a princĂpio. Nesse sentido, a existĂȘncia de aves capazes de falar torna essa relação ainda mais complexa e evidencia que as dificuldades de estabelecer o limite entre o animal e o humano se estendem alĂ©m dos primatas e envolvem as mais inusitadas espĂ©cies zoolĂłgicas.Since ancient times, parrots and their allies (Psittacidae) have fascinated Europeans by their striking colors and notable ability to interact with human beings. The discovery of the New World added new species to the international exotic animal trade, which for many centuries had brought beasts to Europe from Africa and the Orient. Lacking large mammals, tropical America participated in this trade with its most appealing species, essentially felines, primates and birds - especially parrots - which were shipped in large numbers. It should be noted, however, that at times these birds were not well liked. In fact, according to documents from colonial Brazil, only the ants rank higher than parrots as the animals most often mentioned as agricultural pests. On the other hand, some of these birds were so chatty that people suspected them to be demonic or possessed animals, since only three classes of beings - angels, men and demons - have the ability to speak. Nowadays, several Psittacidae still constitute a threat to agriculture, and the suspicion that extremely talkative birds were demon possessed has also survived. More than a joke or a mere curiosity, this belief exemplifies how intricate manâs relationships with the ânatural worldâ may be. In this sense, the existence of birds that are able to speak adds a further twist to these relationships, demonstrating that the problem of establishing a boundary between the animal and the human does not only involve primates, but also includes some unusual zoological species
Freezing and Thawing of Agricultural Soils: Implications for Soil, Water, and Air Quality
Most agricultural lands in the USA are subject to subfreezing temperatures. Soil freezing and thawing affects both biotic and abiotic interactions and processes which vary with weather, soil type, land management, and topography. Soil fauna generally undergo physiological changes or rely on locomotion as a means of adapting to frozen soils. Managing faunal populations using soil management may be achievable with a better understanding of winter ecological processes. Many of the thermal, hydraulic, mechanical, and physical properties of soils are altered by freezing and thawing. Soil erosion may be accentuated by soil freezing and thawing as a result of changes in aggregate stability and shear strength. Soil processes such as heat, water, solute, and gas flux are affected by the freezing process, although simulation of solute and gas flux in frozen soils is not well documented. Solute and gas flux affect water and air quality owing to the loss of chemicals to surface and ground water systems and gaseous emissions to the atmosphere, respectively. Information about biotic and abiotic characteristics of frozen soils, presented at a national workshop in March 1994 in Minnesota, aids in the development of sound management strategies for agricultural lands to preserve our soil, water, and air resource
Extended studies of rating broad crested V-notch weirs with narrow sloping approach channels
CER78-79JFR53.USDA-ARS Specific Agreement No. 12-14-3001-556.A report of research conducted cooperatively by the USDA Agricultural Research Service, North Central Region, North Central Watershed Research Unit, Columbia, Missouri and the Colorado State University, Engineering Research Center, Fort Collins, Colorado.Includes bibliographical references (pages xxi, 78-79).October 1979
AN IRRIGATION MODEL FOR MANAGEMENT OF LIMITED WATER SUPPLIES
A two-stage simulation/mathematical programming model is presented for determining the optimal intraseasonal allocation of irrigation water under conditions of limited water supply. The model is applied to a series of water shortage scenarios under both surface and center pivot irrigation. Economically efficient irrigation management is shown to involve the coordination of a number of managerial decisions, including irrigation scheduling, crop substitution, the adoption of improved irrigation labor practices, and idling land. The results indicate that significant opportunities exist for conserving water in the study area under both surface and center pivot irrigation