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An office building of unusual design has been monitored for more than three years. Numerous submeters allow tracking of energy end use. The building was designed to make significant use of daylighting, with some passive solar heating, and an emphasis on night ventilation cooling of thermal mass. The overall building end usages are compared to those of three zones of varying orientation, spatial character, size, and population. Insights about daylight-sensing controls of indirect electric lighting, “task heating,” and night ventilation of mass and air quality are presented.

To determine if treatment with subantimicrobial-dose (SD) doxycycline hyclate (20-mg tablets taken twice daily) improved clinical outcome, had any detectable effect on skin flora, led to overgrowth or colonization of skin by opportunistic pathogens, or resulted in an increase in antibiotic resistance by the surface skin microflora in patients with moderate acne compared with placebo.Multicenter, double-blind, randomized, placebo-controlled, parallel-group trial.Two university-based clinics.Adults (N = 51) with moderate facial acne.Patients were randomized to receive SD doxycycline (Periostat; CollaGenex Pharmaceuticals Inc, Newtown, Pa) or placebo twice daily for 6 months. MAIN EFFICACY OUTCOMES: Primary: changes from baseline in numbers of inflammatory, noninflammatory, and total lesions. Secondary: changes from baseline of individual counts of papules, pustules, and nodules and global assessments of clinical improvement by patient and physician.Forty patients completed 6 months of treatment. At 6 months, the SD doxycycline group had a significantly greater percent reduction in the number of comedones (P.01), inflammatory and noninflammatory lesions combined (P.01), and total inflammatory lesions (P.05) than did the placebo group. They also had significantly greater improvement according to the clinician's global assessment (P =.03). There were no significant differences in microbial counts between groups and no evidence of change in antibiotic susceptibility or colonization by potential pathogens. The treatment was well tolerated.Twice-daily SD doxycycline treatment significantly reduced the number of inflammatory and noninflammatory lesions in patients with moderate facial acne, was well tolerated, had no detectable antimicrobial effect on the skin flora, and did not result in any increase in the number or severity of resistant organisms.

The simulation of an electroacoustic transducer such as a loudspeaker system requires a mathematical model that can serve as the basis for building a computer model. We have three kinds of elements in a loud speaker : electrical, mechanical, and acoustical. Understanding the model and the results of the simu lation suggests that we not follow the traditional path of converting the mechanical and acoustical eZe ments to equivalent electrical elements to form an electrical network as the model to study. Instead, we have found it easier to follow a scheme originally suggested by Larrowe1,3 and form a model based on stating all physical laws in an integral formulation. In modern notation, this is simply accomplished by drawing a signal flow graph as a mathematical model of the system. The resulting signal flow graph (if we use the "right" technique) has an optimum set of state variables in the sense that all quantities are of clear physical significance in the system. For a loudspeaker system, the state variables turn out to be voice-coiz current, voice-coil velocity, voice- coil displacement, cabinet pressure, and volume velocity at the vent. Once this signal flow graph has been drawn, an analog computer model can be formed by proper insertion of minus signs and scale factors. The state-variable differential equation read from the signal flow graph can be converted to a phasor equation and then solved by complex matrix inversion. A time-shared computer terminal or a minicomputer programmed in BASIC is a convenient way to implement a digital simulation of an electro acoustic transducer.

An X-band source of excellent frequency stability is needed in infrared frequency multiplication of high order. Such a source has been used in frequency multiplication by a factor of 401 using a point-contact Josephson junction as a frequency multiplier and mixer. Noise data on three X-band systems are reported. Two of these systems use klystrons as the source of X-band power; the other uses a Gunn oscillator. Each of these three systems employs both cavity and injection stabilization. Injection stabilization, using a quartz-oscillator-driven multiplier chain, provides the second-to-second and minute-to-minute stability needed for the Josephson junction experiment. To our knowledge, this is the first published noise data where cavity and injection stabilization are simultaneously employed. The quality of the best system reported here is much better-both around 1 Hz from the carrier and around 50 kHz from the carrier?than the source used to multiply by a factor of 401 to 3.8 THz.

The need for a three‐way line‐source array‐loudspeaker system for reinforcement of a symphony orchestra in a summer outdoor concert is discussed. Electrical tapering of a line‐source array‐loudspeaker makes possible an octave range in a single array. An array 3.6 m long is crossed over to an array 2.4 m long at 200 Hz by an active third‐order Butterworth filter. The midfrequency column is crossed over at 2 kHz to a horn tweeter array with a passive network. Performance data from 40 Hz to 10 kHz will be given.