bluuebunny/crossref_metadata_2025_split huggingface dataset:
Masers in AGN environments
Authors: Greenhill L. J. 
Published: January 2008

AbstractGalactic nuclei are well known sources of OH and H2O maser emission. It appears that intense star formation in ultra-luminous infrared galaxies drives most OH sources. In contrast, nuclear activity appears to drive most H2O sources. When H2O emission originates in accretion disk structures, constrained geometry and dynamics enable robust interpretation of spectroscopic and imaging data. The principal science includes study of AGN geometry at parsec and sub-parsec radii and measurement of geometric distances in the Hubble Flow. New high accuracy estimates of the “Hubble constant, H○” obtained from maser distances may enable new substantively improved constraints on fundamental cosmological parameters (e.g., dark energy).
An atlas of extragalactic water vapor masers
Authors: Braatz J. , Kondratko P. , Greenhill L. , Condon J. , Henkel C. , Gugliucci N. , Hao L. , Reid M. , Moran J. , Lo K.-Y. 
Published: January 2008

AbstractWe present an atlas of extragalactic water vapor masers. As of 2007, one hundred galaxies have been detected as sources of water vapor maser emission, two thirds of them discovered since 2003. Extragalactic water masers fall in at least three categories: those associated with nuclear jets or winds, those in starbursts or star-forming regions, and those in AGN accretion disks. While all maser systems offer the possibility of unique investigations into their physical environments, it is the disk masers that have been most aggressively sought because of their potential for use as precision distance indicators. Type 2 Seyfert and LINER galaxies are hosts to such disk masers. Insingle-dish spectra, disk masers are often revealed by the presence of high-velocity emission features (defined roughly by having anomalous velocities in excess of 200 km s−1). About one third of the extragalactic water masers detected to date show evidence of disk origin. Only a few galaxies are currently identified as jet-type or star-forming type. The remaining systems show only a few narrow doppler components, usually near the systemic velocity, and are difficult to categorize. These unclassified systems are detected toward AGNs and are also possibly associated with disks or winds near the nucleus. Detection rates in large maser surveys are typically 5% or less, but the observing efficiency and sensitivity of the Green Bank Telescope (GBT) allow for short integration times (typically 10 minutes to detect a narrow 30 mJy line) so many galaxies can be searched. Recently, GBT surveys targeting type 2 Seyfert galaxies identified by the SDSS have been the most productive, identifying 17 systems in surveys observed during 2006.
Masers in starburst galaxies
Authors: Darling Jeremy 
Published: January 2008

AbstractMasers in starburst galaxies are outstanding probes of a range of phenomena related to galaxy and black hole evolution, and offer unique high brightness temperature illumination that can be used to probe small scales in the host galaxy and in our own. But we require a deeper understanding of the galaxy-scale maser phenomenon if we wish to employ starburst galaxy masers as probes using the next generation of radio telescopes. This review summarizes what is known about the different flavors of masers in starburst galaxies and the setting and structure of OH megamasers. The question of which galaxies produce megamasers and which do not is critical to our understanding of the megamaser phenomenon, and recent studies of HCN and H2CO are particularly instructive. Constraints on the lifetime of OH megamasers and the predictability of OH megamaser line properties are critical issues to address in the near future. It is also time to begin the next wave of OH megamaser surveys at higher redshifts and to finally employ them as probes of starbursts, massive black holes, galaxy evolution, and intervening media.
OH main line masers in the M 82 starburst
Authors: Argo M. K. , Pedlar A. , Muxlow T. W. B. , Beswick R. J. 
Published: January 2008

AbstractA study of the distribution of OH gas in the central region of the nearby active starburst galaxy M82 has confirmed two previously known bright masers and revealed several new main line masers. Three of these are seen only at 1665 MHz, one is detected only at 1667 MHz, while the rest are detected in both lines. Observations covering both the 1665 and 1667 MHz lines, conducted with both the Very Large Array (VLA) and the Multi-Element Radio Linked Interferometer Network (MERLIN), have been used to accurately measure the positions and velocities of these features. This has allowed a comparison with catalogued continuum features in the starburst such as HII regions and supernova remnants, as well as known water and satellite line OH masers. Most of the main line masers appear to be associated with known HII regions although the two detected only at 1665 MHz are seen along the same line of sight as known supernova remnants.
Exciting maser science with new instruments – the promise of the EVLA
Authors: Menten Karl M. 
Published: January 2008

AbstractIn the near future, the Expanded Very Large Array (EVLA) will allow surveys for maser sources with unprecedented sensitivity, spectral coverage and spectroscopic capabilities. In particular, comprehensive surveys for many maser species with simultaneous sensitive continuum imaging and absorption studies will give a comprehensive radio picture of star formation in the Galactic plane and elsewhere. Very efficient EVLA surveys for H2O megamasers in Active Galacic Nuclei will be possible to practically arbitrary redshifts.EVLA and Atacama Large Millimeter Array (ALMA) studies of H2O and SiO masers will serve as high resolution probes of the innermost envelopes of oxygen-rich evolved stars and HCN masers of carbon-rich stars.Farther in the future, the Square Kilometer Array (SKA) promises the detection of OH gigamasers at all conceivable redshifts and maser astrometry with unprecedented accuracy.
ALMA's view of maser emission
Authors: Wootten Alwyn 
Published: January 2008

AbstractALMA, the Atacama Large Millimeter/submillimeter Array, provides a large collecting area at a location on a high dry site, endowing it with unparalleled potential for sensitive spectral line observations. Its wide frequency coverage, superb receivers and flexible backend will ensure that that potential is met. Although in the Southern Hemisphere, its tropical latitude ensures good coverage of the northern sky. Since the last meeting on astrophysical masers, the ALMA team has substantially enhanced its capability for line observations. Japan's entry into ALMA has provided increased sensitivity with the addition of the 16 antennas of the Atacama Compact Array, equivalent to eight additional 12m telescopes. The first four cartridges for the baseline ALMA receiver packages (to be augmented by three other bands owing to Japanese participation) have been accepted, with performance above the already-challenging specifications. At first light, ALMA will offer nearly complete frequency coverage of the millimeter and submillimeter spectral windows, ensuring coverage of a variety of masering transitions. ALMA's flexibility as a spectrometer has increased with the enhancement of the baseline correlator with tunable filter banks, and with the addition of a separate correlator for the ACA. As an example of the increased flexibility, ALMA is now capable of multi-spectral-region and multi-resolution modes. With the former, one might observe e.g. four separate transitions anywhere within one of four 2 GHz bands with a high resolution bandwidth. With the latter, one might simultaneously observe with low spectral resolution over a wide bandwidth and with high spectral resolution over a narrow bandwidth. Thus, one could simultaneously cover an extremely broad velocity range while providing high spectral resolution of groups of lines within that range. Several science examples will be presented illustrating ALMA's potential for transforming the millimeter and submillimeter study of masers.
Mild Hypothermia Improves Transient Gene Expression Yields Several Fold in Chinese Hamster Ovary Cells
Authors: Wulhfard Sarah , Tissot Stéphanie , Bouchet Sophie , Cevey Jean , de Jesus Maria , Hacker David L. , Wurm Florian M. 
Published: January 2008

AbstractLarge‐scale transient gene expression (TGE) in mammalian cells is a rapid method to generate recombinant proteins, but the volumetric productivity for secreted proteins is still more than an order of magnitude lower than the yields typically achieved with recombinant cell lines. Here transient recombinant protein production in Chinese hamster ovary cells transfected with linear 25 kDa polyethylenimine was significantly enhanced by incubation of the cells at temperatures ranging from 29 to 33 °C after DNA delivery. With this approach, transient recombinant antibody yields of 60–80 mg/L were achieved within 6 days of transfection. The increase in TGE correlated with the accumulation of cells in the G1 phase of the cell cycle, increased cell size, higher cell viability, higher steady‐state levels of transgene mRNA, reduced consumption of nutrients, and decreased accumulation of waste products. The enhancement of TGE was not vector‐dependent, but the presence of the woodchuck hepatitis virus post‐transcriptional regulatory element in the 3′ untranslated region of the transgene mRNA increased transient recombinant antibody expression more than 3‐fold at 31 °C as compared to expression at 37 °C. The yields achieved by the low‐temperature enhancement of TGE in CHO cells makes this technology feasible for the rapid production of gram amounts of secreted recombinant proteins at large scale (up to 100 L).
Differences in Daily Energy Expenditure in Lean and Obese Women: The Role of Posture Allocation
Authors: Johannsen Darcy L. , Welk Gregory J. , Sharp Rick L. , Flakoll Paul J. 
Published: January 2008

Objective: A low resting metabolic rate (RMR) is considered a risk factor for weight gain and obesity; however, due to the greater fat‐free mass (FFM) found in obesity, detecting an impairment in RMR is difficult. The purposes of this study were to determine the RMR in lean and obese women controlling for FFM and investigate activity energy expenditure (AEE) and daily activity patterns in the two groups.Methods and Procedures: Twenty healthy, non‐smoking, pre‐menopausal women (10 lean and 10 obese) participated in this 14‐day observational study on free‐living energy balance. RMR was measured by indirect calorimetry; AEE and total energy expenditure (TEE) were calculated using doubly labeled water (DLW), and activity patterns were investigated using monitors. Body composition including FFM and fat mass (FM) was measured by dual energy X‐ray absorptiometry (DXA).Results: RMR was similar in the obese vs. lean women (1601 ± 109 vs. 1505 ± 109 kcal/day, respectively, P = 0.12, adjusting for FFM and FM). Obese women sat 2.5 h more each day (12.7 ± 3.2 h vs. 10.1 ± 2.0 h, P < 0.05), stood 2 h less (2.7 ± 1.0 h vs. 4.7 ± 2.2 h, P = 0.02) and spent half as much time in activity than lean women (2.6 ± 1.5 h vs. 5.4 ± 1.9 h, P = 0.002).Discussion: RMR was not lower in the obese women; however, they were more sedentary and expended less energy in activity than the lean women. If the obese women adopted the activity patterns of the lean women, including a modification of posture allocation, an additional 300 kcal could be expended every day.
Observational Study of Bone Accretion During Successful Weight Loss in Obese Adolescents
Authors: Stettler Nicolas , Berkowtiz Robert I. , Cronquist Joanna L. , Shults Justine , Wadden Thomas A. , Zemel Babette S. , Leonard Mary B. 
Published: January 2008

Objective: To assess bone mineral content (BMC) among obese adolescents who lose weight during a critical period for bone accretion.Methods and Procedures: Whole body, lumbar spine, lower, and upper limb BMC were measured in 62 obese adolescents who completed an intensive 12‐month weight loss trial. BMC was adjusted for height (z ‐scores) using data from a reference group of 66 adolescents (who were 18% overweight).Results: At baseline, the BMC of the obese group was higher than the reference group. During the 12‐month weight loss program, unadjusted BMC increased among the obese adolescents, despite successful weight loss. After adjustment for height, whole body BMC did not change significantly from baseline to 12 months (mean ± s.d.: 1.08 ± 0.67 to 1.06 ± 0.67, P = 0.7). Region‐specific BMC‐for‐height however decreased for the lower (1.07 ± 0.57 to 0.95 ± 0.59, P < 0.001) and upper (1.29 ± 0.56 to 1.18 ± 0.57, P = 0.01) limbs, but lumbar spine BMC‐for‐height increased (0.14 ± 1.06 to 0.40 ± 0.94, P < 0.001). These changes were largely and independently explained by changes in lean and fat mass.Discussion: This study confirms that obese adolescents have high BMC for height and suggests that, unlike adults, their BMC continues to increase during weight loss and remains higher than the BMC of a reference group. After adjustment for growth‐related changes, lower and upper limb BMC appears to decrease, while lumbar spine BMC appears to increase. These results suggest that to optimize the health benefits of weight loss among obese adolescents, their bone health should be better understood and addressed.
Familial Aggregation of Metabolic Syndrome and Its Components in a Large Chinese Population
Authors: Feng Yan , Zang Tonghua , Xu Xiping , Xu Xin 
Published: January 2008

Objective: To investigate the familial aggregation of metabolic syndrome (MetS) and its components in the Chinese.Methods and Procedures: A total of 17,954 subjects from 5,224 families with multiple siblings aged 25–64 years old (mean age 45.8 years, 51.6% male) were enrolled from a rural area of Anhui Province of China during 2004–2005. Anthropometric measurement, body composition, blood pressure, plasma lipids, and fasting glucose and insulin, as well as a questionnaire interview, were obtained from each participant.Results: Significant correlations among siblings were observed in all the traits examined, including BMI, waist circumference, total body and abdominal fat percentage, fasting plasma glucose (FPG) and insulin, insulin resistance index of homeostatic model assessment (HOMA‐IR), total cholesterol, triglyceride, high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol, and blood pressure, after adjustment for age, gender and some other covariates. The correlation coefficients varied from 0.18 for FPG to 0.42 for HDL‐C. In stratified analyses, we found siblings with a smaller age gap among them had higher intraclass correlation coefficients (ICCs) for most of the above phenotypes than those with a greater age difference, and the correlation of systolic blood pressure (SBP) was stronger in male siblings than that in female. If the eldest sibling is affected by MetS or any of its components, younger siblings bear a twofold to threefold higher risk for developing MetS or any of its components than those with a healthy eldest sibling.Discussion: Our study demonstrated a significant familial resemblance as regards MetS and its components among the Chinese. Further studies are warranted to investigate specific genetic and environmental factors related to MetS in this population.
Correlates of State Legislative Action to Prevent Childhood Obesity
Authors: Cawley John , Liu Feng 
Published: January 2008

Objective: To determine the factors associated with state legislative action to address childhood obesity.Methods and Procedures: This paper has an ecologic study design, with data on each US state from 2003 to 2006. Data on whether a bill was introduced in the state legislature and whether a law was enacted to address childhood obesity were linked to a rich set of independent variables concerning state political and socioeconomic characteristics that were drawn from a variety of sources. The association between state legislative action and state political and socioeconomic characteristics was measured using probit regression.Results: From 2003 to 2005 there was an increasing trend toward the introduction of bills and enactment of laws to address childhood obesity. State legislative action on childhood obesity was more likely in states with a greater gap between adults' actual and desired weight, a higher percentage of college‐educated adults, a higher percentage of African‐American residents, a Democratic governor, or a legislature not controlled by Republicans.Discussion: The socioeconomic conditions of the state and its political climate strongly predict legislative action to address childhood obesity. The finding that Democratic governors and state legislatures not controlled by Republicans are associated with greater policy action against obesity suggests that the 2006 election may result in additional action against obesity in certain states. This study can also be used to guide the efforts of public health advocates, who can achieve greater success by targeting their efforts toward states with conducive political environments.
Alteration of Dietary Fat Intake to Prevent Weight Gain: Jayhawk Observed Eating Trial
Authors: Donnelly Joseph E. , Sullivan Debra K. , Smith Bryan K. , Jacobsen Dennis J. , Washburn Richard A. , Johnson Susan L. , Hill James O. , Mayo Matthew S. , Spaeth Kendra R. , Gibson Cheryl 
Published: January 2008

Objective: To examine the effects of ad libitum diets with three distinct levels of fat intake for the prevention of weight gain in sedentary, normal‐weight and overweight men and women.Methods and Procedures: Three hundred and five participants were randomized to one of three diets. The diets targeted <25% of energy from fat (low fat (LF)), between 28 and 32% of energy from fat (moderate fat (MF)), or >35% of energy from fat (high fat (HF)). Participants consumed two meals per day on weekdays and one meal per day on weekends in a university cafeteria over a 12‐week period. Energy and nutrient content of cafeteria foods were measured by digital photography. All meals and snacks consumed outside the cafeteria were measured by dietary recall. All analysis of energy and nutrient content was completed using Nutrition Data System for Research (NDS‐R) version 2005.Results: Two hundred and sixty participants completed the study. LF gained 0.1 ± 3.1 kg, MF gained 0.8 ± 2.5 kg, and HF gained 1.0 ± 2.2 kg and there was no gender or age effect. Longitudinal mixed modeling indicated a significant difference among the groups in weight over time (P = 0.0366). When adjusting for total energy intake, which was a significant predictor of weight over time, the global effect for the group was eliminated. Thus, increasing weight was a function of increasing energy but not increasing percentage of fat intake.Discussion: Energy intake, but not percentage of energy from fat, appears responsible for the observed weight gain. LF diets may contribute to weight maintenance and HF diets may promote weight gain due to the influence of fat intake on total energy intake.
Gender Differences in Predictors of Body Weight and Body Weight Change in Healthy Adults
Authors: Chiriboga David E. , Ma Yunsheng , Li Wenjun , Olendzki Barbara C. , Pagoto Sherry L. , Merriam Philip A. , Matthews Charles E. , Hebert James R. , Ockene Ira S. 
Published: January 2008

Background: Overweight and obesity are important predictors of a wide variety of health problems. Analysis of naturally occurring changes in body weight can provide valuable insights in improving our understanding of the influence of demographic, lifestyle, and psychosocial factors on weight gain in middle‐age adults.Objective: To identify gender‐specific predictors of body weight using cross‐sectional and longitudinal analyses.Methods and Procedures: Anthropometric, lifestyle and psychosocial factors were measured at baseline and then quarterly for 1 year in 572 healthy adult volunteers from Central Massachusetts who were recruited between 1994 and 1998. Linear mixed models were used to analyze the relationship between body weight and potential predictors, including demographic (e.g., age, educational level), lifestyle (e.g., diet, physical activity, smoking), and psychosocial (e.g., anxiety, depression) factors.Results: Over the 1‐year study period, on average, men gained 0.3 kg and women lost 0.2 kg. Predictors of lower body weight at baseline in both men and women included current cigarette smoking, greater leisure‐time physical activity, and lower depression and anxiety scores. Lower body weights were associated with a lower percentage of caloric intake from protein and greater occupational physical activity levels only among men; and with higher education level only among women. Longitudinal predictors of 1‐year weight gain among women included increased total caloric intake and decreased leisure‐time physical activity, and among men, greater anxiety scores.Discussion: Demographic, lifestyle and psychosocial factors are independently related to naturally occurring changes in body weight and have marked differential gender effects. These effects should be taken into consideration when designing interventions for weight‐loss and maintenance at the individual and population levels.
Obesity and Physical Activity Among Aboriginal Canadians
Authors: Katzmarzyk Peter T. 
Published: January 2008

Objective: To investigate ethnic differences in obesity and physical activity among Aboriginal and non‐Aboriginal Canadians.Methods and Procedures: The sample included 24,279 Canadians (1,176 Aboriginals, 23,103 non‐Aboriginals) aged 2–64 years from the 2004 Canadian Community Health Survey (CCHS). Adult participants were classified as underweight/normal weight, overweight (BMI 25–29.9 kg/m2) or obese (BMI ≥ 30 kg/m2). Children and youth 2–17 years of age were classified as normal weight, overweight or obese based on the International Obesity Task Force criteria. Leisure‐time physical activity levels over the previous 3 months were obtained by questionnaire in those aged 12–64 years.Results: The prevalence of obesity in adults was 22.9% (men: 22.9%; women: 22.9%), and the prevalence was higher among Aboriginals (37.8%) compared to non‐Aboriginals (22.6%). The prevalence of obesity in children and youth was 8.2% (boys: 9.2%; girls: 7.2%), and the prevalence was higher among Aboriginals (15.8%) compared to non‐Aboriginals (8.0%). In both youth and adults, the odds for obesity were higher among Aboriginals (youth: OR = 2.3 (95% CI: 1.4–3.8); adults: OR = 2.4 (95% CI: 1.6–3.6)) after adjustment for a number of covariates. There were no ethnic differences in the prevalence of physical inactivity; however, physical inactivity was a predictor of obesity in both the Aboriginal and non‐Aboriginal samples.Discussion: The prevalence of obesity is higher among Canadian Aboriginals compared to the rest of the population. Further research is required to better delineate the determinants of obesity and the associated health consequences in this population.