Small Unit Size Research Articles

Physiologic versus cognitive factors in short term food regulation in the obese and nonobese.

Sixteen obese and 16 nonobese subjects were given, on 4 consecutive days, drinks which contained 200 or 600 calories and appeared half the time to be rich milkshakes and half the time to be low-calorie diet liquids. Food intake after the drinks were consumed was measured each day at a standardized test meal consisting of quarter sandwiches served 20 minutes later. The actual number of calories consumed prior to the test meal was found to have no effect on intake. However, subjects ate significantly less (.025 level) and reported feeling fuller after consuming the drink designed to appear high-calorie. No differences were found between obese and nonobese subjects. Of additional interest were the large quantities eaten by the subjects at the test meal and their tendency to underestimate their intake. The small size of the food units served may have caused subjects to lose count and overeat.

Copolymers of 1‐methylcyclopropene

Abstract1‐Methylcyclopropene (MCP) copolymerizes rapidly with acrylic and vinyl monomers to form soluble, high molecular weight products containing enchained cyclopropane rings. The high electron availability in the cyclopropene double bond promotes one‐to‐one alternating copolymerization with sulfur dioxide, maleic anhydride, acrylic acid, acrylonitrile, dialkyl fumarates and acrylic esters. Nonalternating copolymers are obtained with vinyl chloride and vinyl acetate, and attempted copolymerization fails entirely with styrene, α‐methylstyrene and isoprene. This pattern of copolymerization reactivity resembles that of highly compressed ethylene. Methylcyclopropene copolymers have high glass temperatures in spite of the small size of the MCP unit. The combination of high Tg and small size allows preparation of copolymers with high Tg having a wide range of ductilities and cohesive energy densities.

Motor units in the stapedius muscle.

PREVIOUS studies have shown that the stapedius muscle of several vertebrates including man is uniquely endowed with a rich neuromuscular substrate. This substrate is presumably required for the finely coordinated contractions exhibited by the muscle in effectively dampening the transmission of potentially damaging frequencies of sound across the middle ear. It is characterized by an exceedingly rich motor nerve supply, small motor unit sizes, and limited sensory innervation compared to other skeletal muscles. 1-6 These features of nerve-muscle relationships are now well established for middle ear muscles, but there are no observations concerning the effect of age, acoustic trauma, or pathological conditions on the number of nerve and muscle fibers or the ratio of nerve fibers to muscle fibers (ie, the size of the motor unit). Constant bombardment by sound, susceptibility to infection or degenerative change, and normal aging processes are forces which continuously influence the efficiency of the middle

Density of cosmic-ray neutrons in the atmosphere

Neutrons are produced in the atmosphere by the interaction of cosmic-ray particles with the nuclei of nitrogen and oxygen. The density of these neutrons was determined experimentally by means of ionization chambers filled with B^(10), B^(11)F_3, and argon. The ion- ization current resulting from the B^(10)(n,α)Li^7 reaction was obtained as a function of pressure altitude from 760 grams cm^(-2)(8,000 ft) to 6 grams cm^(-2)(115,000 ft) in a series of balloon flights at a geomagnetic latitude of 41 °N. By comparing the current from the ionization chamber to the counting rate of a B^(10)F_3 proportional counter, when irradiating the instruments with a thermal neutron source, an absolute calibration of the ionization current in terms of thermal neutron density was made. The large volume of the ionization chambers (9 liters) resulted in a significant reduction of statistical errors relative to earlier balloon flights. The small size of the flight units (3 kilograms) avoided the problems associated with local neutron production and moderation which are present in airplane measurements. The data show a maximum in the neutron density of 4.8 ± 1.2 x 10^(-7) neutrons cm^(-3) at a pressure altitude of 100 g cm^2 (53,000 ft), a rapid decline above this altitude, and an exponential decrease below 250 g cm^(-2) with an absorption length of 165 ± 20 g cm^(-2). If the data are extrapolated to the top of the atmosphere by the use of neutron transport theory, a value of 1.6 ± 0.8 x 10^(-8) neutrons cm^(-3) is obtained. These results are in reasonable agreement with the work of the New York University Cosmic-Ray Croup (2,3).

A New Type of Ferroelectric Shift Register

Ferroelectric shift registers having completely independent parallel or serial inputs and outputs have been designed and constructed. The principal components of these shift registers are single crystals of barium titanate and silicon junction diodes. Two ferroelectric units and two to three silicon junction diodes are required for each stage of the shift register. Practical operating speeds for 10-stage shift registers with transistor drives are at present from 0 to 5 kc. The small size of the ferroelectric units and the low power consumption in this speed range make the ferroelectric shift register attractive for many digital circuit applications.