4,551 research outputs found

    Workshop and desk study to appraise technical difficulties associated with organic pullet rearing

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    Background To date, Regulation (EC) 1804/1999 and UKROFS Standards allow conventionally reared pullets up to 18 weeks of age to be brought into systems of organic egg production. Pullets must be reared according to the rules laid down in Regulation (EC) 1804/1999 and according to UKROFS Standards for at least six weeks, before the eggs may be sold as organic eggs. The derogation for pullet rearing has been agreed for a transitional period expiring on 31 December 2003. If pullets are to be reared from day old in an organic system in accordance with Regulation (EC) 1804/1999 and UKROFS Standards this may potentially create a number of technical problems, which may disadvantage UK producers considering organic egg production. A series of workshops and a literature review were commissioned by MAFF to provide possible solutions to these technical problems. Objectives 1. To organise a workshop involving key members of the egg sector of the poultry industry, representatives of organic sector bodies and of MAFF to consider technical problems that may occur when rearing pullets organically, and to identify possible solutions. 2. To address some of the perceived technical problems by reviewing the available literature on conventional pullet rearing and assessing the extent to which published results can be applied to organic systems. 3. To reconvene workshop members to discuss findings from the literature review, to identify research priorities and to consider mechanisms for technology transfer. Methodology There were three separate but related stages to the project. Stage one comprised a workshop involving representatives of the egg sector of the poultry industry, of the Soil Association, of ADAS and of MAFF, and attendees were specifically invited to comment on the likely difficulties that might be experienced when attempting to rear pullets in an organic production system. Stage two was a desk study in the form of a literature review. Literature searches of the major international abstracting databases were done using key words related to the technical problems highlighted by workshop one attendees. Stage three was a second workshop where attendees discussed the findings from the literature, identified research priorities and considered mechanisms for technology transfer. Results The outcome of workshop one was that several likely difficulties associated with rearing pullets in an organic production system were identified and these included; 1) the application of light programmes in pullets receiving natural light when the maximum daily light period is 16 hours; 2) nutrition; 3) housing and pasture management, and; 4) food safety risks. Implications of findings, future work and policy relevance The implications of the findings are that with current scientific information there will be technical difficulties associated with rearing pullets in an organic system. The most important technical difficulties are to do with photoperiodism, nutrition, pasture management and rotation, and methods of controlling injurious feather pecking. Also a maximum permissible daylength of 16 hours for rearing organic pullets would mean that producers in Northern European countries may be disadvantaged. The project addressed MAFF’s policy of supporting the development of organic livestock production within the UK. The project has provided information to MAFF and the egg sector of the poultry industry about the key technical problems associated with organic pullet rearing, possible solutions to these problems and, where scientific information is missing, future research needs have been identified

    Crop phenology literature review for corn, soybean, wheat, barley, sorghum, rice, cotton, and sunflower

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    There are no author-identified significant results in this report

    Timing avian long-distance migration: from internal clock mechanisms to global flights

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    Migratory birds regularly perform impressive long-distance flights, which are timed relative to the anticipated environmental resources at destination areas that can be several thousand kilometres away. Timely migration requires diverse strategies and adaptations that involve an intricate interplay between internal clock mechanisms and environmental conditions across the annual cycle. Here we review what challenges birds face during long migrations to keep track of time as they exploit geographically distant resources that may vary in availability and predictability, and summarize the clock mechanisms that enable them to succeed. We examine the following challenges: departing in time for spring and autumn migration, in anticipation of future environmental conditions; using clocks on the move, for example for orientation, navigation and stopover; strategies of adhering to, or adjusting, the time programme while fitting their activities into an annual cycle; and keeping pace with a world of rapidly changing environments. We then elaborate these themes by case studies representing long-distance migrating birds with different annual movement patterns and associated adaptations of their circannual programmes. We discuss the current knowledge on how endogenous migration programmes interact with external information across the annual cycle, how components of annual cycle programmes encode topography and range expansions, and how fitness may be affected when mismatches between timing and environmental conditions occur. Lastly, we outline open questions and propose future research directions

    Prediction of photoperiodic regulators from quantitative gene circuit models

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    Photoperiod sensors allow physiological adaptation to the changing seasons. The external coincidence hypothesis postulates that a light-responsive regulator is modulated by a circadian rhythm. Sufficient data are available to test this quantitatively in plants, though not yet in animals. In Arabidopsis, the clock-regulated genes CONSTANS (CO) and FLAVIN, KELCH, F-BOX (FKF1) and their lightsensitive proteins are thought to form an external coincidence sensor. We use 40 timeseries of molecular data to model the integration of light and timing information by CO, its target gene FLOWERING LOCUS T (FT), and the circadian clock. Among other predictions, the models show that FKF1 activates FT. We demonstrate experimentally that this effect is independent of the known activation of CO by FKF1, thus we locate a major, novel controller of photoperiodism. External coincidence is part of a complex photoperiod sensor: modelling makes this complexity explicit and may thus contribute to crop improvement

    Measurement of plant growth in view of an integrative analysis of regulatory networks

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    As the regulatory networks of growth at the cellular level are elucidated at a fast pace, their complexity is not reduced; on the contrary, the tissue, organ and even whole-plant level affect cell proliferation and expansion by means of development-induced and environment-induced signaling events in growth regulatory processes. Measurement of growth across different levels aids in gaining a mechanistic understanding of growth, and in defining the spatial and temporal resolution of sampling strategies for molecular analyses in the model Arabidopsis thaliana and increasingly also in crop species. The latter claim their place at the forefront of plant research, since global issues and future needs drive the translation from laboratory model-acquired knowledge of growth processes to improvements in crop productivity in field conditions

    Lighting as a Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment

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    The human brain can only accommodate a circadian rhythm that closely follows 24 hours. Thus, for a work schedule to meet the brain’s hard-wired requirement, it must employ a 24 hour-based program. However, the 6 hours on, 12 hours off (6/12) submarine watchstanding schedule creates an 18-hour “day” that Submariners must follow. Clearly, the 6/12 schedule categorically fails to meet the brain’s operational design, and no schedule other than one tuned to the brain’s 24 hour rhythm can optimize performance. Providing Submariners with a 24 hour-based watchstanding schedule—combined with effective circadian entrainment techniques using carefully-timed exposure to light—would allow crewmembers to work at the peak of their daily performance cycle and acquire more restorative sleep. In the submarine environment, where access to natural light is absent, electric lighting can play an important role in actively entraining—and closely maintaining—circadian regulation. Another area that is likely to have particular importance in the submarine environment is the potential effect of light to help restore or maintain alertness
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