5,516 research outputs found
The Production Rate and Employment of Ph.D. Astronomers
In an effort to encourage self-regulation of the astronomy job market, I
examine the supply of, and demand for, astronomers over time. On the supply
side, I document the production rate of Ph.D. astronomers from 1970 to 2006
using the UMI Dissertation Abstracts database, along with data from other
independent sources. I compare the long-term trends in Ph.D. production with
federal astronomy research funding over the same time period, and I demonstrate
that additional funding is correlated with higher subsequent Ph.D. production.
On the demand side, I monitor the changing patterns of employment using
statistics about the number and types of jobs advertised in the AAS Job
Register from 1984 to 2006. Finally, I assess the sustainability of the job
market by normalizing this demand by the annual Ph.D. production. The most
recent data suggest that there are now annual advertisements for about one
postdoctoral job, half a faculty job, and half a research/support position for
every new domestic Ph.D. recipient in astronomy and astrophysics. The average
new astronomer might expect to hold up to 3 jobs before finding a steady
position.Comment: 5 pages, 4 figures, 2 tables, PASP accepte
White Dwarf Asteroseismology and the ^12C(alpha,gamma)^16O Rate
Due to a new global analysis method, it is now possible to measure the
internal composition of pulsating white dwarf stars, even with relatively
simple theoretical models. The precise internal mixture of carbon and oxygen is
the largest single source of uncertainty in ages derived from white dwarf
cosmochronometry, and contains information about the rate of the
astrophysically important, but experimentally uncertain, ^12C(alpha,gamma)^16O
nuclear reaction. Recent determinations of the internal composition and
structure of two helium-atmosphere variable (DBV) white dwarf stars, GD 358 and
CBS 114, initially led to conflicting implied rates for the
^12C(alpha,gamma)^16O reaction. If both stars were formed through single-star
evolution, then the initial analyses of their pulsation frequencies must have
differed in some systematic way. I present improved fits to the two sets of
pulsation data, resolving the tension between the initial results and leading
to a value for the ^12C(alpha,gamma)^16O reaction rate that is consistent with
recent laboratory measurements.Comment: 4 pages, 2 figures, 1 table, uses emulateapj5.sty; Accepted for
publication in ApJ Letter
Associations of Body Composition, Maximum Strength, Power Characteristics With Sprinting, Jumping, and Intermittent Endurance Performance in Male Intercollegiate Soccer Players
The purpose of this study was to determine the relationships between body composition, strength, power characteristics, sprinting, jumping, and intermittent endurance performance in collegiate male players. Twenty-three players participated (19.7 ± 1.6 yrs; 71.8 ± 7.1 kg; 176.5 ± 5.1 cm). Measurements of interest in body composition included body fat percentage (BF%), lean body mass (LBM), and body mass (BM). Power characteristics were measured with an unloaded squat jump (SJ0) and loaded SJ at 20 kg (SJ20) and 40 kg (SJ40), and unloaded countermovement jump (CMJ0). Power assessments included peak power (PP) and PP allometrically scaled (PPa). Strength characteristics were assessed using isometric mid-thigh pull. Strength assessment included isometric peak force (IPF) and IPF allometrically scaled (IPFa). Performance measures included 10m and 20 m sprint time, CMJ0 jump-height, and Yo-Yo intermittent endurance test level 1 distance. Significant correlations ranging from moderate to very large were found for LBM and CMJ jump height (CM0 JH) (p = 0.01, r = 0.50); BF% and sprint times at 10 m (p = 0.03, r = 0.44) and 20 m (p = 0.02, r = 0.50). PP and PPa from SJ0 and CMJ0 were significantly correlated to 10m sprint time (p \u3c 0.05, r = −0.45 to −0.53) and 20 m sprint time (p \u3c 0.05, r = −0.40 to −0.49). Our findings agree with previous literature in that body composition and power characteristics are directly related to soccer-related performance
Acculturation and the body image of Alaska Native Women
This study examined the way acculturation affects Alaska Native women’s body perception. A secondary goal was to establish an understanding of interactions of native peoples with the majority society. Little research has been conducted regarding the ways in which indigenous people are affected by societal norms, although much research has identified how immigrant people groups are affected. It was hypothesized that while the ideal body image of both cultures may be similar as a result of adherence to cultural norms, the Alaska Native sample would be more accepting of their bodies than the White Alaskan sample. It was hypothesized for this study that the more acculturated Alaska Native women to Western culture, the more likely they would be to have a similar ideal body image to that of the majority culture. This study used two sample groups, one Native Alaskan women and the other White Alaskan women. Both sample groups were asked to use the Body Image Assessment – Obesity (BIA-O) to measure their perceived ideal body image and the body shape closest to their own body image. The Alaska Native group was also asked to fill out a Cultural Lifestyle Inventory (CLI) which assessed their level of acculturation. The scores on the BIA-O and the CLI were then compared to determine if the level of acculturation had an effect on the body images of the Alaska Natives. Further, the Alaska Native group’s BIA-O scores were compared to the White Alaskan sample group to determine if there was a difference in perceived ideal body image between the groups. The results suggest there is a significant difference between how Alaska Native women perceive their ideal body types and how White women perceive their ideal body type. There is also some suggestion that the level of acculturation is a predictor in ideal body image for the Alaska Native women. Therefore, Western acculturation appears to be a significant determinant of body image. This suggests some adherence to the majority culture by the Alaska Native women living in urban settings
Between Chicken Worm and Sunken Boat : bounded masculinity in the Chinese sex industry = 在「雞蟲」與「沉船」之間 : 華人性工業中的玩界男性化特質
Drawn from 24 in-depth interviews and 2 focus group discussions conducted since 2012 with Hong Kong men who buy sex (‘male clients’) in the Chinese sex industry, this paper discusses men’s involvement with commercial sex in relation to their male identity.
A few types of client masculinity have been identified: ‘Chicken worm’ (or McSex masculinity) refers to those men who are proud of paying for rather impersonal sex with as many women as they wish whilst ‘sunken boat’ (or Titanic masculinity) refers to those men who passionately seek intense emotional intimacy with sex workers. Between these two opposing types, ‘bounded’ masculinity refers to those men who seek emotionally responsive women in a time-bounded romance. It is this type, which emphasizes the containment of ‘excess’ sexuality and the compartmentalization of sexual and emotional needs, that is privileged in the clients’ perspective as it allows the satisfaction of recreational sexuality without challenging the companionate model of marriage/coupled relationship. It is also this type of client masculinity that negotiates risks at the normative ‘edge’ of social behavior while enjoying the thrill of commercial sex. Buying sex could thus be seen as a form of leisure edgework which involves the fundamental boundary of negotiation between order and chaos.
Through a sociological analysis of men’s commercial sexual experiences in Hong Kong, this research examines the meaning and nature of intimacy and rethinks masculinity in relation to the changing gender order between the sexes under the new urban sexual culture of post-industrial capitalism.
本研究自 2012 年開始,以華人性工業中付錢買性的香港男性為對象 (「男嫖客」),進行了二十四個深入訪談和兩個焦點小組討論,探討他們在性交易過程中所衍生 的男性身份問題。
嫖客的男性化特質可以分為若干類型 :「雞蟲」(或麥性事式的男性化特質) 是指那些以與愈多女性進行性交易為榮的嫖客;「沉船」(或鐵達尼式的男性化特質) 是指那些渴望與性工作者發展親密關係的嫖客。而在兩者之間,「玩界」男性化特質是指那些只在既定時間內尋找情感依戀的嫖客。從嫖客的角度而言,這種男性化特質強調保留「過盛」的性慾,以及劃分性愛和情感的需要,好處是能夠在 享受消閒的性歡愉之時亦不會挑戰他們現有同伴式的婚姻或伴侶關係。它代表了 在享受性交易所帶來的刺激之時,需要在規範化的「邊界」上與相關的風險進行協商。因此,買性可以被視為一種消閒式的邊界活動,當中牽涉秩序與混亂之間 的邊界協商過程。
透過對香港男嫖客的性交易經驗進行社會學分析,本研究旨在探討親密關係的意 義和本質,並且重新思索在後工業資本主義帶動的新都市性文化下,所牽涉的男 性化特質與兩性之間性別秩序轉變的關係
Beef Cattle Salmonellosis: A Study of Oral Salmonella typhimurium and Topical Salmonella newport Inoculations
Cattle are frequently infected with salmonellae by fecaloral transmission or by being fed contaminated animal protein byproducts (40% are reported contaminated in the U.S.). Bothcould propagate salmonellosis in feedlots. Research indicates that stress can induce shedding of salmonellae by asymptomatic carriers. Stress factors associated withsalmonellosis include: transportation, starvation, changes in ration, overcrowding, age, pregnancy, parturition, exertion, anesthesia, surgery, intercurrentdisease, and oral treatment withantibioticsand anthelmintics. In this study, we have attempted to correlate dosage of S. typhimurium inoculumwithdisease, persistence of infection, and environmental contamination. The persistence and spread of S. newport placed on the skin of cattle was also studied
Trajectory planning for unmanned surface vehicles operating under wave-induced motion uncertainty in dynamic environments:
We present a deliberative trajectory planning method to avoid collisions with traffic vessels. It also plans traversal across wavefields generated by these vessels and minimizes the risk of failure. Our method searches over a state-space consisting of pose and time. And, it produces collision-free and minimum-risk trajectory. It uses a lookup table to account for motion uncertainty and failure risk. We also present speed-up techniques to increase performance. Our wave-aware planner produces plans that (1) have shorter execution times and safer when compared to previously developed reactive planning schemes and (2) comply with user-defined wave-traversal constraints and Collision Regulations (COLREGs
Beef Cattle Salmonellosis: A Study of Oral Salmonella typhimurium and Topical Salmonella newport Inoculations
Cattle are frequently infected with salmonellae by fecaloral transmission or by being fed contaminated animal protein byproducts (40% are reported contaminated in the U.S.). Bothcould propagate salmonellosis in feedlots. Research indicates that stress can induce shedding of salmonellae by asymptomatic carriers. Stress factors associated withsalmonellosis include: transportation, starvation, changes in ration, overcrowding, age, pregnancy, parturition, exertion, anesthesia, surgery, intercurrentdisease, and oral treatment withantibioticsand anthelmintics. In this study, we have attempted to correlate dosage of S. typhimurium inoculumwithdisease, persistence of infection, and environmental contamination. The persistence and spread of S. newport placed on the skin of cattle was also studied
Identifying a Test to Monitor Weightlifting Performance in Competitive Male and Female Weightlifters
Monitoring tests are commonly used to assess weightlifter’s preparedness for competition. Although various monitoring tests have been used, it is not clear which test is the strongest indicator of weightlifting performance. Therefore, the purpose of this study was to (1) determine the relationships between vertical jump, isometric mid-thigh pull (IMTP) and weightlifting performance; and (2) compare vertical jumps to IMTP as monitoring tests of weightlifting performance in a large cohort of male and female weightlifters. Methods: Fifty-two competitive weightlifters (31 males, 21 females) participated in squat and countermovement jump testing (SJ, CMJ), and IMTP testing performed on force plates. All laboratory testing data was correlated to a recent competition where the athletes had attempted to peak. Results: Squat jump height (SJH) was the strongest correlate for men and women with the Sinclair Total (r = 0.686, p ≤ 0.01; r = 0.487, p ≤ 0.05, respectively) compared to countermovement jump height (r = 0.642, p ≤ 0.01; r = 0.413, p = 0.063), IMTP peak force allometrically scaled to body mass (r = 0.542, p ≤ 0.01; r = −0.044, p = 0.851) and rate of force development at 200 ms (r = 0.066, p = 0.723; r = 0.086, p = 0.711), respectively. Further, SJH was a stronger correlate of relative weightlifting performance compared to IMTP peak force in females (p = 0.042), but not male weightlifters (p = 0.191). Conclusions: Although CMJ and IMTP are still considered strong indicators of weightlifting performance, SJH appears to be the most indicative measure of weightlifting performance across a wide-range of performance levels. Thus, SJH can be used as a reliable measure to monitor weightlifting performance in male and female weightlifters
Spatially Resolved Outflows in a Seyfert Galaxy at z = 2.39
We present the first spatially resolved analysis of rest-frame optical and UV
imaging and spectroscopy for a lensed galaxy at z = 2.39 hosting a Seyfert
active galactic nucleus (AGN). Proximity to a natural guide star has enabled
high signal-to-noise VLT SINFONI + adaptive optics observations of rest-frame
optical diagnostic emission lines, which exhibit an underlying broad component
with FWHM ~ 700 km/s in both the Balmer and forbidden lines. Measured line
ratios place the outflow robustly in the region of the ionization diagnostic
diagrams associated with AGN. This unique opportunity - combining gravitational
lensing, AO guiding, redshift, and AGN activity - allows for a magnified view
of two main tracers of the physical conditions and structure of the
interstellar medium in a star-forming galaxy hosting a weak AGN at cosmic noon.
By analyzing the spatial extent and morphology of the Ly-alpha and
dust-corrected H-alpha emission, disentangling the effects of star formation
and AGN ionization on each tracer, and comparing the AGN induced mass outflow
rate to the host star formation rate, we find that the AGN does not
significantly impact the star formation within its host galaxy.Comment: 16 pages, 5 figures, accepted for publication in Ap
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