THE DIGESTIBILITY AND VOLUNTARY INTAKE OF S22 AND H.1 RYEGRASS, S170 TALL FESCUE, S48 TIMOTHY, S215 MEADOW FESCUE AND GERMINAL COCKSFOOT

Pure swards of S22 Italian ryegrass, H.1 hybrid ryegrass, S170 tall fescue, S48 timothy, S215 meadow fescue and Germinal cocksfoot were each harvested at several stages of maturity during first growth in the spring, and in the subsequent regrowths. Each batch of herbage was fed to sheep in a digestion trial under conditions of voluntary intake. Results from the first growth herbages showed the expected fall in digestibility with increasing maturity. However, the digestibility of S22, H.1, S170 and S48 began to fall well before ear emergence, whereas the digestibility of Germinal fell only slowly up to the time of ear emergence, as had been found previously with S24 and S23 ryegrass and S37 cocksfoot. The rate of fall of digestibility in H.1 and S48 (0.4 units/day) also appeared to be lower than with the perennial ryegrasses and cocksfoot (0.5 units/day). The monthly regrowths within each herbage were of similar digestibility, but the mean digestibility of regrowths differed between herbages, being highest for S215 and lowest for Germinal and S170. The grasses with highest digestibility in the early Spring, in particular S22 ryegrass, were not, however, always the most digestible in the subsequent regrowths. The numbers of sheep fed on each herbage were insufficient to show whether there were significant differences in voluntary intake between different herbage species of the same digestibility. It is suggested that an intake/digestibility relationship, based on data from more animals, should be developed for each herbage species. Only if different relationships are found can it be concluded that factors other than level of digestibility have an effect on intake.     

Terraclor (PCNB) for control ofRhizoctonia solani. II. PCNB residues in tubers

Terraclor (PCNB) applied to soils by broadcast and row slightly reduced the incidence ofRhizoctonia solani but did not increase yield or per cent of U. S. No. 1 tubers either by weight or numbers. Residues of PCNB in tubers grown in treated soils increased as the rate per acre of PCNB increased. Almost all of the residues were in the tuber peel.     

DRIED FORAGES AND BEEF PRODUCTION*

The vuluntary Intake of dried forage by young cattle rises with increasing D value and with increasing proportions of fine particles in the compressed package (wafer, coh, or pellet). Higher intakes are accompanied hy higher live–weight gains per day and per unit of food consumed. When different amounts of pellets or cobs of dried forage of high D value or protein content are fed with silage of high digestibility, maximum liveweight gains at lowest food cost have been ohtained with 35–50% dried forage in the diet. The dried forage gave results comparable with alternative supplements of energy or protein fed with the same silage. Hie application of the results of short-term experiments in systems of heef production is discussed.     

A MATHEMATICAL RELATIONSHIP BETWEEN NITROGEN INPUT AND OUTPUT IN CUT GRASS SWARDS

The importance of predicting grass N yield lies in its controlling influence on grass DM output and thus on animal production. Results from 88 experiments studying the use of fertilizer N on cut grass swards show that the major part (97%) of the variation in grass N yield could be explained in terms of fertilizer N rate, an estimate of soil N and an interaction between the two. From this, it appears that high fertilizer N recovery is associated with a high uptake of soil N and vice versa.     

A user-centric approach for information modelling in arable farming

Agriculture and farmers face a great challenge in effectively manage information both internally and externally in order to improve the economic and operational efficiency of operations, reduce environmental impact and comply with various documentation requirements. As a part of meeting this challenge, the flow of information between decisions processes defined as realizing a decision must be analyzed and modelled as a prerequisite for the subsequent design, construction and implementation of information systems.This paper defines the actors, their role and communication specifics associated with the various decision and control processes in farmers’ information management. Core-task analysis and core task demands from earlier research are utilised as premises for the modelling of information flow from the farmers’ point of view. A user-friendly generic FMIS design reference model is the primary objective for the study in which planning, execution and evaluation measures have been incorporated.A user-centric approach to model the information flows for targeted field operations is presented. The information models are centred around the farmer as the principal decision maker and involves external entities as well as mobile unit entities as the main information producers. This is a detailed approach to information modelling that will enable the generation of a Farm Management Information System in crop production.     

Essential regulation of CNS angiogenesis by the orphan G protein-coupled receptor GPR124

The orphan G protein-coupled receptor (GPCR) GPR124/tumor endothelial marker 5 is highly expressed in central nervous system (CNS) endothelium. Here, we show that complete null or endothelial-specific GPR124 deletion resulted in embryonic lethality from CNS-specific angiogenesis arrest in forebrain and neural tube. Conversely, GPR124 overexpression throughout all adult vascular beds produced CNS-specific hyperproliferative vascular malformations. In vivo, GPR124 functioned cell-autonomously in endothelium to regulate sprouting, migration, and developmental expression of the blood-brain barrier marker Glut1, whereas in vitro, GPR124 mediated Cdc42-dependent directional migration to forebrain-derived, vascular endothelial growth factor-independent cues. Our results demonstrate CNS-specific angiogenesis regulation by an endothelial receptor and illuminate functions of the poorly understood adhesion GPCR subfamily. Further, the functional tropism of GPR124 marks this receptor as a therapeutic target for CNS-related vascular pathologies.     

High-flux solar-driven thermochemical dissociation of CO2 and H2O using nonstoichiometric ceria

Because solar energy is available in large excess relative to current rates of energy consumption, effective conversion of this renewable yet intermittent resource into a transportable and dispatchable chemical fuel may ensure the goal of a sustainable energy future. However, low conversion efficiencies, particularly with CO(2) reduction, as well as utilization of precious materials have limited the practical generation of solar fuels. By using a solar cavity-receiver reactor, we combined the oxygen uptake and release capacity of cerium oxide and facile catalysis at elevated temperatures to thermochemically dissociate CO(2) and H(2)O, yielding CO and H(2), respectively. Stable and rapid generation of fuel was demonstrated over 500 cycles. Solar-to-fuel efficiencies of 0.7 to 0.8% were achieved and shown to be largely limited by the system scale and design rather than by chemistry.     

Electrical resistance of long conjugated molecular wires

The charge transport mechanism of a wire can be revealed by how its electrical resistance varies with length. We have measured the resistance and current-voltage characteristics of conjugated molecular wires ranging in length from 1 to 7 nanometers, connected between metal electrodes. We observe the theoretically predicted change in direct-current transport from tunneling to hopping as a function of systematically controlled wire length. We also demonstrate that site-specific disruption of conjugation in the wires greatly increases resistance in the hopping regime but has only a small effect in the tunneling regime. These nanoscale transport measurements elucidate the role of molecular length and bond architecture on molecular conductivity and open opportunities for greater understanding of electrical transport in conjugated polymer films.     

保育期中后段乳糖水平对断奶仔猪生产性能影响的评价

试验在3所大学进行,选用1320头杂交仔猪,旨在评价饲粮中不同乳糖水平对保育期阶段3（保育期共4个阶段）即断奶后第3和4周仔猪生产性能的影响。仔猪在15～20d断奶（初始体重6.2kg）,并分配到5个处理中,每个处理有24个重复（每所大学饲喂8个重复）,其中两所大学的16个重复中,每个重复含5头试猪,另外1所大学的8个重复中,每个重复含23头试猪。断奶后第1周,所有仔猪均采食复合阶段1饲粮（含乳糖20%）;断奶后第2周,所有仔猪均采食复合阶段2饲粮（含乳糖15%）。断奶后第3和4周仔猪采食阶段3饲粮,乳糖含量分别为0,2.5%,5.0%,7.5%或10.0%,然后所有仔猪采食1～2周（阶段4）相同的玉米豆粕饲粮。乳糖来源为乳宝80,含乳糖80%。阶段1,2和3饲粮在相同场所配制。隔周称量仔猪体重,并计算饲粮采食量。研究表明,在最初2周内,采食相同饲粮的所有试猪间平均日增重、日饲料采食量和增重饲料比均没有显著差异（P=0.10）。在3和4周（阶段3）饲喂5种不同乳糖水平饲粮,随着乳糖水平的增加,平均日增重、平均日饲料采食量线性增加（P〈0.01）,但是增重饲料比不受影响（P=0.10）。阶段3中乳糖水平为7.5%时,虽然二次指标（增重饲料比）差异不显著,但是平均日增重和平均日饲料采食量最高。与饲喂不添加乳糖饲粮的试猪相比,饲喂乳糖水平为7.5%的饲粮的试猪体增重多增长350g·只^-1,同时多消耗饲粮420g·只^-1,且多增长的体重（294g·只^-1）大部分维持到断奶后5～6周即试验结束时。结论：仔猪对保育期中后段饲粮中乳糖含量做出相应应答,且这些应答在不同的管理和设施条件下获得。