Present Tense Bisexuality

A review of Steven Angelides's A History of Bisexuality (University of Chicago Press, Chicago, 2001)

The Aesthetic Revival

A review of Bether Hinderliter, William Kaizen, Vered Maison, Jaleh Mansoor and Seth McCormick (eds), Communities of Self: Rethinking Aesthetics and Politics (Duke, 2009

Critical Fluctuations in Beam-Plasma Systems and Solar Type III Radio Bursts

It is shown that the Langmuir waves are excited similar to critical fluctuations during phase transitions when the negative absorption due to electron beam traveling radially outward in the solar atmosphere is balanced by the positive absorption due to collisions in the corona and due to scattering on electron density inhomogeneities in the interplanetary medium. The effective temperature of the Langmuir fluctuations range from 1011 to 1013 K, explaining the majority of the type III bursts. The Rayleigh scattering and direct coupling due to density gradient as well as due to density inhomogeneities are discussed in the context of fundamental radiation and the combination scattering for second harmonic. The number density of electrons in type III beams is estimated and compared with observations. It is also shown that the stabilization of type III beams is achieved automatically since the instability does not develop in the case of critical fluctuations

Phase Coupling in Langmuir Wave Packets: Evidence for Four Wave Interactions in Solar Type III Radio Bursts

The four wave interaction process, known as the oscillating two stream instability (OTSI) is considered as one of the mechanisms responsible for stabilizing the electron beams associated with solar type III radio bursts. It has been reported that (1) an intense localized Langmuir wave packet associated with a type III burst contains the spectral characteristics of the OTSI: (a) a resonant peak at the local electron plasma frequency, f(sub pe), (b) a Stokes peak at a frequency slightly lower than f(sub pe), (c) anti-Stokes peak at a frequency slightly higher than f(sub pe), and (d) a low frequency enhancement below a few hundred Hz, (2) the frequencies and wave numbers of these spectral components satisfy the resonance conditions of the OTSI, and (3) the peak intensity of the wave packet is well above the thresholds for the OTSI as well as spatial collapse of envelope solitons. Here, for the first time, applying the trispectral analysis on this wave packet, we show that the tricoherence, which measures the degree of coherent four-wave coupling amongst the observed spectral components exhibits a peak. This provides an additional evidence for the OTSI and related spatial collapse of Langmuir envelope solitons in type III burst sources

High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions

Short wavelength ion sound waves (2-4kHz) are detected in association with the Langmuir waves (~15-30kHz) in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified

Learning about sex: Results from Natsal 2000.

11-13 September 2002

Increasing prevalence of male homosexual partnerships and practices in Britain 1990-2000: evidence from national probability surveys.

OBJECTIVES: To estimate the prevalence and timing of homosexual experience among British men; to explore the patterns of sexual practices and partnerships in 2000, and behavioural and attitudinal changes between 1990 and 2000 among men who have sex with men (MSM). DESIGN: Two large, stratified probability sample surveys of the general population. METHODS: Trained interviewers administered a combination of face-to-face and self-completion questionnaires to men aged 16 to 44 years resident in Britain (n = 6000 in 1990 and n = 4762 in 2000). RESULTS: In 2000, 2.8% of British men reported sex with men in the past 5 years. 46.0% of MSM reported five or more partners in the past 5 years, and 59.8% reported unprotected anal intercourse in the past year. A total of 33.0% of MSM reported one or more female partner(s) in the past year. In comparison with 1990, there was a significant increase in the proportion of MSM in the population in 2000, and among these men, in the proportion reporting receptive anal intercourse in the past year [age-adjusted odds ratio (OR), 2.08; 95% confidence interval (CI), 1.08-4.00], but no significant change in self-perceived HIV-risk (age-adjusted OR, 1.11; 95% CI, 0.49-2.51) or HIV testing in past 5 years (age-adjusted OR, 1.14; 95% CI, 0.57-2.25). CONCLUSIONS: Evidence of increasing prevalence of homosexual intercourse among the British male population coupled with increases in some HIV-risk behaviours among MSM suggests overall increasing numbers at risk in the population. Although these changes may partly reflect an increased willingness to report these behaviours, our results are consistent with increasing incidence of sexually transmitted infections and behavioural surveillance data

Reported sexually transmitted disease clinic attendance and sexually transmitted infections in britain: prevalence, risk factors, and proportionate population burden.

BACKGROUND: We examined attendance at sexually transmitted disease (STD) clinics and the prevalence, distribution, and associated demographic and behavioral factors of self-reported sexually transmitted infections (STIs) in a population survey of sexual attitudes and lifestyles. METHODS: We analyzed data from stratified probability sample surveys obtained through the British National Surveys of Sexual Attitudes and Lifestyles (Natsal), which was undertaken in 1990 (n=13,765) and 2000 (n=11,161) among men and women aged 16-44 years. National STD surveillance data for 1999 were used to determine disease- and risk factor-specific proportionate population burden (PPB). RESULTS: Between 1990 and 2000, the number of subjects who reported having attended an STD clinic during the past 5 years increased from 4.3% to 7.6% among men and from 3.3% to 6.6% among women. In 2000, 3.0% of men and 4.0% of women reported having received a diagnosis of an STI during the past 5 years; 77.6% of men and 60.3% of women with an STI had attended an STD clinic. Reported STI acquisition was independently associated with age, increasing numbers of sex partners, male homosexual partners, and partners from abroad (for women only). Of all reported STIs during the past 5 years (PPB, 10.2%), 10.2% were reported by the 2.9% of men who reported having had homosexual partners during the past 5 years. Of all reported STIs in the past 5 years (PPB, 41.6%), 41.6% were reported by the 4.0% of women who reported having > or =10 sex partners during that time. Analysis of national STI surveillance data showed that the PPB for new episodes of Chlamydia trachomatis diagnosed among homosexual men was 2.8%, that for gonorrhea was 17.4%, and that for syphilis was 32.1%. CONCLUSIONS: Numbers and types of sexual partnerships remain the dominant individual and population risk factors for STI acquisition. Combined population behavior and surveillance data demonstrate the high PPB for STIs attributable to key risk factors. PPB may be a useful indicator of epidemic "phase" and may help target resources and guide prevention strategies