Magnetic flux transport on the sun

Although most of the magnetic flux observed on the sun originates in the low-latitude sunspot belts, this flux is gradually dispersed over a much wider range of latitudes by supergranular convective motions and meridional circulation. Numerical simulations show how these transport processes interact over the 11-year sunspot cycle to produce a strong "topknot" polar field, whose existence near sunspot minimum is suggested by the observed strength of the interplanetary magnetic field and by the observed areal extent of polar coronal holes. The required rates of diffusion and flow are consistent with the decay rates of active regions and with the rotational properties of the large-scale solar magnetic field.     

Alleviation of postanesthetic hypoxemia in the horse

This study was designed to investigate the effect of the nasotracheal insufflation of oxygen at a flow rate of 15 L/min on the arterial partial pressure of oxygen during the recovery period following inhalation anesthesia in the horse. It has been stated that this is a suitable flow rate to prevent postoperative hypoxemia but without any experimental evidence to support those statements. Horses being used for the study of healing of cartilage were anesthetized on two separate occasions. Following one period of anesthesia they were allowed to recover breathing room air, and following the other period of anesthesia oxygen was insufflated into the trachea at 15 L/min throughout the recovery period. This permitted each horse to act as its own control and allowed statistical analysis using Student's t-test for paired samples.

The insufflated horses had a higher arterial partial pressure of oxygen during the recovery period than did the noninsufflated horses (p < 0.05).

     

Rearing temperature and the meat yield of broilers

1. One hundred and twenty (60 male and 60 female) 21‐d‐old Ross 1 broiler chicks were reared in cages in rooms kept at 21°C or 31°C and were killed at body weights of 1.0, 1.5, 2.0, 2.5 or 3.0 kg.

2. Birds reared at either of the two temperatures ate similar quantities of food to reach their slaughter weight although at 31°C they took longer to reach it.

3. The meat yields of the birds at each slaughter weight were similar at both rearing temperatures, but at body weights greater than 2.0 kg, the broilers reared at 21 °C had more breast meat than those reared at 31°C.

4. Females ate more food than males to reach each of the slaughter weights. The females deposited more fat and had a greater skin weight than the males and, although they had a similar amount of total meat, they had more breast meat.     

Diurnal and seasonal occurrence,feeding habits and mating behavior ofMaladera matrida adults in Israel

Adult populations ofMaladera matrida Argaman (Coleoptera: Scarabaeidae), a beetle highly injurious to agricultural crops, were studied in the coastal plain of Israel from 1985 to 1988. There were two generations annually. Adults emerged in March, April or May and disappeared in October or November. The beetles are on the wing, mate, and feed at twilight and in the dark. Feeding and mating behavior, sex ratio, and preferred food plants were studied.     

The significance of VA-Mycorrhiza to future arable farming in the Netherlands

Present conditions of high inputs and narrow rotations render the importance of vesicular-arbuscular mycorrhiza (VAM) in arable farming in the Netherlands rather low. Changes expected in the near future under the influence of economic pressures and environmental problems may change this situation. This is discussed in the light of some such expected changes in Dutch arable farming.De huidige Nederlandse akkerbouw is zeer intensief. Ze heeft in het algemeen een nauwe rotatie met slechts enkele gewassen (aardappelen, granen en suikerbieten) en een ruime toepassing van kunstmest en bestrijdingsmiddelen. Het is te verwachten dat er onder invloed van toenemende problemen met het milieu, afnemende bodemproduktiviteit en lagere prijzen voor nu geteelde gewassen ten gevolge van overschotten een tendens zal zijn in de richting van een meer geïntegreerde landbouw. In de bestaande akkerbouw werken zowel hoge kunstmestgiften (met name N en P) en bestrijdingsmiddelen negatief op VAM-vorming. Naarmate het gebruik van kunstmest en bestrijdingsmiddelen in de nabije toekomst wellicht zal verminderen, kan worden verwacht dat zowel de aanwezigheid als het belang van VAM in de nederlandse landbouw zal toenemen. Het laatste zal vooral het geval zijn indien de vruchtwisseling wordt verruimd met de teelt van andere gewassen (zoals vlinderbloemigen) met een hogere VAM-afhankelijkheid dan die van het huidige gewasassortiment. Het zou zeer verstandig zijn zich reeds nu te beraden over vormen van bedrijfsvoering die VAM zoveel mogelijk stimuleren en daardoor meer profijt trekken van de door deze symbiose geboden voordelen.     

The detection and measurement of stray electrical leakages on dairy farms: effects on performance

Sources of stray electrical leakage from Power Supply Authority alternating current (AC), fence energiser pulses and randomly generated pulses and spikes on 55 dairy farms in the Waikato area were identified between December 1986 and March 1988. The electrical measurements were made using a specifically designed voltmeter able to detect voltages between 0.1V and 1500V, from single voltage spikes of two microseconds or greater duration from direct current (DC) as well as 50 Hz AC. Ninety-five sources of stray voltage were identified, and 53 per cent of properties had more than one source of >0.5V. The major source was from electric fence energisers. Rotary platform parlours were among the commonest sources of random or transient voltage spikes. Leakage of AC into one or other of the components of the milk transport system such as vat, plate cooler, milk lift pump and milk line was common. Owners acknowledged the improvements in milk production, reproductive performance and growth rate of calves after reduction of the exposure of dairy cattle to stray electrical leakage. A representative summary of five case records helps define the range of improvements that may possibly be achieved.