Basic Energy Requirements Research Articles

The foraging behaviour and diet of red squirrels Sciurus vulgaris receiving supplemental feeding

The effect of ad libitum supplemental feeding upon the diet and foraging behaviour of red squirrels Sciurus vulgaris was studied in a coniferous habitat during May 1994 ‐ July 1996. Although supplemental feeding in the form of peanuts was widely available, the animals continued to exploit natural foods such as pine seed, buds and flowers. The degree to which pine seed was exploited was a function of pine cone availability. In contrast, peanut consumption was not correlated with peanut availability, but was determined by the abundance of pine cones. During late winter and spring when seed was becoming scarce, peanuts contributed 30–56% of the dietary items. In addition, increasing amounts of alternative ‘low energy’ foods such as buds and flowers were also exploited. These foods are calcium rich and their ingestion would compensate for the high phosphorus content of peanuts. The nutritional composition of peanuts appears to have restricted the degree to which they could be included in the diet. Nevertheless peanuts were an important dietary component, and seasonally contributed 25–181% of the animals' basic daily energy requirements. Supplemental feeding was associated with relatively large amounts of activity occurring on the ground (annual mean estimates were 47 and 50% of total foraging time). The animals continued to exhibit ‘scatter‐hoarding’ behaviour, with peanuts accounting for 90% of the identified cached items. This stored resource could satisfy 344 (1994/95) and 198 (1995/96) days of the animals' basic energy requirements.

The Dyadosphere of black holes and gamma-ray bursts

The dyadosphere has been defined (Ruffini, Preparata et al.) as the region outside the horizon of a black hole endowed with an field (abbreviated to EMBH for electromagnetic black hole) where the field exceeds the critical value, predicted by Heisenberg & Euler for $e^+ e^-$ pair production. In a very short time ($\sim O(\hbar/(mc^2))$), a very large number of pairs is created there. We here give limits on the EMBH parameters leading to a Dyadosphere for $10M_{\odot}$ and $10^5M_{\odot}$ EMBH's, and give as well the pair densities as functions of the radial coordinate. We here assume that the pairs reach thermodynamic equilibrium with a photon gas and estimate the average energy per pair as a function of the EMBH mass. These data give the initial conditions for the analysis of an enormous pair-electromagnetic-pulse or P.E.M. pulse which naturally leads to relativistic expansion. Basic energy requirements for gamma ray bursts (GRB), including GRB971214 recently observed at $z=3.4$, can be accounted for by processes occurring in the dyadosphere. In this letter we do not address the problem of forming either the EMBH or the dyadosphere: we establish some inequalities which must be satisfied during their formation process.

Brain Anaerobic Lactate Production: A Suicide Note or a Survival Kit?

Aerobic energy metabolism utilizes glucose and oxygen to satisfy all the energy needs of the adult brain. Anaerobically, the brain switches to the significantly less efficient glycolytic pathway for its most basic energy requirements. Anaerobic glycolysis provides the adult brain with a limited amount of energy and time to maintain ion homoeostasis and other essential processes before several events occur that lead to brain cell damage and death. Recent evidence that lactate, produced mainly in glial cells during a period of oxygen deprivation, becomes the only utilizable and thus obligatory substrate for aerobic energy metabolism upon reoxygenation is summarized here. This evidence also supports the hypothesis that a lactate shuttle exists between glia and neurons, and emphasizes its importance in the post-ischemic survival of neurons.

State of the Art of Biomass Combustion

Abstract

Trophic relationships between the kelp gull and the Antarctic limpet at King George Island (South Shetland Islands, Antarctica) during the breeding season

The diet of the kelp gull (Larus dominicanus), its foraging behaviour and the consumption rates on the Antarctic limpet (Nacella concinna) were studied during austral spring and summer 1992/1993 and 1993/1994 at Potter Peninsula, King George Island, Antarctica. Prey information was obtained by collecting 237 pellets, foraging behaviour was observed by focal and instantaneous scan samplings, and consumption rate was estimated by means of weekly sampling of limpets found in 5 nests and their respective middens. Limpets were the most important prey followed by scavenged prey (penguin and seal carcasses), amphipods, snails, fish and euphausiids. Foraging gulls spent 51% of the time searching for limpets, 10% moving between foraging areas, 9% in catching effort and 15% handling prey. The number of gulls observed searching for limpets was inversely correlated with the tidal height. In the diet limpets provide 102.3, 159.4 and 188.1 kJ gull−1 day−1 during incubation, hatching and brooding respectively; these values range between 15 and 27%, with a maximum of 40%, of the basic daily energy requirements of kelp gulls. Total consumption rate estimations for the whole population of gulls at Potter Peninsula reached between 3400 and 4800 limpets day−1, which represents approximately 10–14% of the total annual limpet mortality.

Nutrition and liver disease.

Nutritional support is a key factor in the treatment of cats with hepatic disease. This is the only effective treatment in cats with hepatic lipidosis. The ideal diet would be one that fulfills all the basic energy and nutrient requirements of the patient, allows positive energy balance, provides all the nutrients necessary for liver regeneration, and prevents or aids the recovery from major complications of liver disease. Formulation of diets for cats with hepatobiliary diseases must also take into account their metabolic peculiarities. Anorexia is a common complication of liver disease and clinicians must take the necessary actions to ensure adequate energy and nutrient intake. No single diet will accommodate all patients and nutritional support must be adapted to each individual case based on the type of liver disease, extent of hepatic dysfunction, tolerance to dietary protein, and nutritional status.

2 Understanding cerebral energy metabolism: a key to successful neuroprotection

Aerobic energy metabolism utilizes glucose and oxygen to produce all the energy needs of the brain. Anaerobically, the brain switches to the significantly less efficient glycolytic pathway for its very basic energy requirements. Anaerobic glycolysis provides the brain with a limited amount of energy and time to maintain ion homoeostasis and other essential processes before several events occur that lead to brain cell damage and death. One of the damaging events has been postulated to be lactic acidosis; the accumulation of lactic acid due to increased glucose utilization via anaerobic glycolysis and the inability of lactic acid to exit the brain owing to the blood-brain barrier impermeability. This chapter questions the validity of the lactic acidosis hypothesis. We offer another hypothesis in its place in which lactate produced in the brain during an ischaemic insult becomes the only utilizable, obligatory substrate for aerobic energy metabolism on return of normoxic conditions. This hypothesis is directly supported by data of recent in vitro studies and indirectly by existing data in numerous in vivo studies; for the most part the data have been ignored and until now have remained unexplained. This new hypothesis may force us to re-examine not only our understanding of cerebral energy metabolism but also our approach to cerebral protection and resuscitation.

Role of nutrition during long-term spaceflight

The authors discuss changes in macro- and micro-nutrients which occur in weightlessness and consider factors which help maintain appropriate nutrition during extended space flight. Basic energy requirements and metabolism are reviewed. The discussion of handling of foodstuffs includes protein, fats, carbohydrates, vitamins, folic acid, iron, and selenium. The discussion of fluids and minerals includes fluid intake, sodium, potassium, and calcium. Changes in gastrointestinal function are examined.

Extraction of non-timber forest products, including fodder and fuelwood, in Mudumalai, India

Mudumalai is biologically rich with a wealth of plant and animal life. Increasing human numbers and current patterns of non-timber forest product, fodder and fuelwood extraction threaten the integrity of the ecosystem. Change in management of the protected areas that include the Mudumalai region is needed. In particular, policies relating to grazing and basic energy requirements need to be reexamined. At the same time, mechanisms must be developed to increase rural incomes using means other than exploitation of natural resources.

Physics of a ballistic missile defense: The chemical laser boost-phase defense

The basic physics involved in proposals to use a chemical laser based on satellites for a boost-phase defense are investigated. After a brief consideration of simple physical conditions for the defense, a calculation of an equation for the number of satellites needed for the defense is made along with some typical values of this for possible future conditions for the defense. Basic energy and power requirements for the defense are determined. A summary is made of probable minimum conditions that must be achieved for laser power, targeting accuracy, numbers of satellites, and total sources of power needed.

A STRATEGY TO MAINTAIN TANZANIA'S FUEL WOOD SUPPLY

SUMMARY Present fuelwood harvests in Tanzania exceed the long term allowable cut from indigenous forests. As long as fuelwood provides more than 90% of basic energy requirements national policy must provide for its continuous supply. A renewable resource policy should focus on three primary areas: improved efficiency in utilization of the existing fuelwood supply; an effective village afforestation programme; and improved management and protection of indigenous forests.

Weight Loss in Incubating Albatrosses and Its Implications for Their Energy and Food Requirements

-The weight loss of incubating Black-browed Albatrosses (Diomedea melanophris) and Grey-headed Albatrosses (D. chrysostoma) was measured at Bird Island, South Georgia. The rate of weight loss did not differ significantly either between the sexes or between the species. The results suggest that these two species have the same metabolic requirements. The difference in the quality of their diet leads to estimates of daily food intake considerably higher for the Grey-headed than for the Black-browed albatross. This may have been a factor in the evolution of biennial breeding in the Grey-headed Albatross. The Black-browed Albatross (Diomedea melanophris) and Grey-headed Albatross (D. chrysostoma) are widely distributed in the subantarctic zone. Their breeding biology (Tickell and Pinder 1975) and food and feeding ecology (Prince 1980) have been extensively studied at South Georgia. The timing and duration of events in their breeding cycle are similar although Greyheaded Albatrosses take approximately six weeks longer to complete the cycle. The chicks of the two species grow at different rates (Ricketts and Prince, in press), possibly as a result of difference in diet. The Black-browed Albatross feeds mainly on krill and fish whereas the Grey-headed Albatross feeds principally on squid; krill have a higher energy content (Grantham 1977) than squid (Voss 1973). The basic energy requirements of birds are closely related to their weight. Blackbrowed and Grey-headed albatrosses are similar in size and weight but the different energy content of their food suggests that they may have different energy requirements. We therefore studied the rate of weight loss in incubating birds to assess whether there is any indication of a metabolic difference between these two species.

Male sexual maturation of the tsetse fliesglossina morsitanswestwood andg. austeniNewstead (Dipt., Glossinidae) in relation to blood feeding

AbstractThe effect of blood feeding on male sexual maturation in the tsetse fliesGlossina morsitansWestwood andG. austeniNewstead was studied by comparing copulation and insemination performance of unfed and fed males during the first five days of adult life. These species differed conspicuously, both in the course of maturation and in the influence of blood feeding on it.G. morsitansmales copulated before they could inseminate, and even fed flies did not all inseminate until day 3; unfed flies showed retarded insemination performance by day 2, before copulation performance declined.G. austenimales were less sexually responsive at first, but they nearly always inseminated when they did copulate, even on day 1. Unfed flies showed less increase in copulation performance by day 4, but no decline. Accessory glands were larger inG. austenithanG. morsitansat emergence, and in unfed flies of both species they ceased to grow after day 3. Both accessory gland size and copulation duration (beyond a minimum duration) were related to insemination success in a general way, though copulation duration was quite variable. Vertebrate blood apparently provides male tsetse with specific nutrients or stimuli which promote sexual performance, in addition to basic energy and water requirements. Feeding probably affects insemination inG. morsitansthrough accessory gland development, allowing more complete spermatophore formation and sperm transfer, but its mode of action onG. austenisexual responsiveness is not evident.