10,376 research outputs found
Seasonal Biomass and Carbohydrate Allocation Patterns in Southern Minnesota Curlyleaf Pondweed Populations
Four southern Minnesota populations of curlyleaf pondweed
(
Potamogeton crispus
L.) were sampled monthly from
January 2001 to November 2002 to determine seasonal phenological,
biomass, and carbohydrate allocation patterns.
Low periods of carbohydrate storage in the seasonal phenological
cycle indicate potentially vulnerable periods in the
plant’s life cycle and may be the ideal time to initiate management
and control efforts
Very Small Strangelets
We study the stability of small strangelets by employing a simple model of
strange matter as a gas of non-interacting fermions confined in a bag. We solve
the Dirac equation and populate the energy levels of the bag one quark at a
time. Our results show that for system parameters such that strange matter is
unbound in bulk, there may still exist strangelets with that are stable
and/or metastable. The lifetime of these strangelets may be too small to detect
in current accelerator experiments, however.Comment: 13 pages, MIT CTP#217
Study of cost/benefit tradeoffs for reducing the energy consumption of the commercial air transportation system
Economic studies were conducted for three general fuel conserving options: (1) improving fuel consumption characteristics of existing aircraft via retrofit modifications; (2) introducing fuel efficient derivations of existing production aircraft and/or introducing fuel efficient, current state-of-the-art new aircraft; and (3) introducing an advanced state-of-the-art turboprop airplane. These studies were designed to produce an optimum airline fleet mix for the years 1980, 1985 and 1990. The fleet selected accommodated a normal growth market by introducing somewhat larger aircraft while solving for maximum departure frequencies and a minimum load factor corresponding to a 15% investment hurdle rate. Fuel burnt per available-seat-mile flown would drop 22% from 1980 to 1990 due to the use of more fuel efficient aircraft designs, larger average aircraft size, and increased seating density. An inflight survey was taken to determine air traveler attitudes towards a new generation of advanced turboprops
Circular No. 86 - Coccidiosis of Chicken
Coccidiosis is a highly contagious disease of chickens and other fowls which is widespread and destructive, especially to half-grown chickens. The heaviest losses occur in chicks from 2 to 10 weeks of age. Just prior to and during their first laying season, pullets sometimes become affected with the disease in a chronic form. The cause is a microscopic protozoan parasite, the oocyst form of which is present in the droppings of diseased birds in large numbers. At least three species of the parasite have been recognized in fowls. The severity of the outbreak is thought to be determined by the species of parasite present
Color-flavor locked strange matter and strangelets at finite temperature
It is possible that a system composed of up, down and strange quarks consists
the true ground state of nuclear matter at high densities and low temperatures.
This exotic plasma, called strange quark matter (SQM), seems to be even more
favorable energetically if quarks are in a superconducting state, the so-called
color-flavor locked state. Here are presented calculations made on the basis of
the MIT bag model considering the influence of finite temperature on the
allowed parameters characterizing the system for stability of bulk SQM (the
so-called stability windows) and also for strangelets, small lumps of SQM, both
in the color-flavor locking scenario. We compare these results with the
unpaired SQM and also briefly discuss some astrophysical implications of them.
Also, the issue of strangelet's electric charge is discussed. The effects of
dynamical screening, though important for non-paired SQM strangelets, are not
relevant when considering pairing among all three flavor and colors of quarks.Comment: 17 pp. 15 figs., to appear in Phys. Rev.
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