The Lantern Vol. 16, No. 2, December 1947

• A Little Light • Traitor\u27s Son • The Comeback • Wolf-Dog • Lucky Harry • Security or Progress • To Tell a Story • Endless • What Purpose, Life? • I Would Not Say • Adult Farewell • Springtime Fields • M.W. Armstronghttps://digitalcommons.ursinus.edu/lantern/1044/thumbnail.jp

On the evolution of irradiated turbulent clouds: A comparative study between modes of triggered star-formation

Here we examine the evolution of irradiated clouds using the Smoothed Particle Hydrodynamics ({\small SPH}) algorithm coupled with a ray-tracing scheme that calculates the position of the ionisation-front at each timestep. We present results from simulations performed for three choices of {\small IR}-flux spanning the range of fluxes emitted by a typical {\small B}-type star to a cluster of {\small OB}-type stars. The extent of photo-ablation, of course, depends on the strength of the incident flux and a strong flux of {\small IR} severely ablates a {\small MC}. Consequently, the first star-formation sites appear in the dense shocked layer along the edges of the irradiated cloud. Radiation-induced turbulence readily generates dense filamentary structure within the photo-ablated cloud although several new star-forming sites also appear in some of the densest regions at the junctions of these filaments. Prevalent physical conditions within a {\small MC} play a crucial role in determining the mode, i.e., filamentary as compared to isolated pockets, of star-formation, the timescale on which stars form and the distribution of stellar masses. The probability density functions ({\small PDF}s) derived for irradiated clouds in this study are intriguing due to their resemblance with those presented in a recent census of irradiated {\small MC}s. Furthermore, irrespective of the nature of turbulence, the protostellar mass-functions({\small MF}s) derived in this study follow a power-law distribution. When turbulence within the cloud is driven by a relatively strong flux of {\small IR} such as that emitted by a massive {\small O}-type star or a cluster of such stars, the {\small MF} approaches the canonical form due to Salpeter, and even turns-over for protostellar masses smaller than $\sim$0.2 M$_{\odot}$.Comment: 13 pages, 19 figures, 3 tables. Rendered images of significantly lowered resolution have been deliberately submitted to stay within the maximum permissible limits of size. Also, the original abstract has been shortened. To be published by the Monthly Notices of the RA

The hidden HI-massive LIRG HIZOA J0836-43: Inside-out galaxy formation

HIZOA J0836-43 is an extreme gas-rich ($M_{\rm{HI}}$=7.5\times10^{10} M_{\sun}) disk galaxy which lies hidden behind the strongly obscuring Vela region of the Milky Way. Utilizing observations from the {\it Spitzer Space Telescope}, we have found it to be a luminous infrared starburst galaxy with a star formation rate of \sim 21 M_{\sun} \rm{yr^{-1}}, arising from exceptionally strong molecular PAH emission (L_{7.7\micron} = 1.50 \times 10^{9} L_{\odot}) and far-infrared emission from cold dust. The galaxy exhibits a weak mid-infrared continuum compared to other starforming galaxies and U/LIRGs. This relative lack of emission from small grains suggests atypical interstellar medium conditions compared to other starbursts. We do not detect significant $[$Ne {\sc v}$]$ or $[$O {\sc iv}$]$, which implies an absent or very weak AGN. The galaxy possesses a prominent bulge of evolved stars and a stellar mass of 4.4($\pm$1.4)\times10^{10} M_{\sun}. With its plentiful gas supply and current star formation rate, a doubling of stellar mass would occur on a timescale of $\sim$2 Gyr. Compared to local galaxies, HIZOA J0836-43 appears to be a "scaled-up" spiral undergoing inside-out formation, possibly resembling stellar disk building processes at intermediate redshifts.Comment: 5 pages, 3 figures, 1 table; Accepted for publication in ApJL: August 25 2008. A version with full resolution figures is available at http://spider.ipac.caltech.edu/staff/jarrett/Cluver_ApJL.pd

The Lantern Vol. 17, No. 3, Summer 1949

• All the Silver in Taxco • The Fall • Parlor Games • Something There Is • Friday Night • Evening • Checker-Board Country • A Noise • Expected Up In Heaven Today • When Time Has Torn My Youth • Impression of Deathhttps://digitalcommons.ursinus.edu/lantern/1048/thumbnail.jp

The mass evolution of the first galaxies: stellar mass functions and star formation rates at 4<z<74 < z < 7 in the CANDELS GOODS-South field

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at $z \sim 4,~5,~6~\&~7$ using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at $z \geq 6$ directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations, however we find that the observed $M_{UV}$ - M$_{*}$ relation has a shallow slope more consistent with a constant mass to light ratio and a normalisation which evolves with redshift. Our stellar mass functions have steep low-mass slopes ($\alpha \approx -1.9$), steeper than previously observed at these redshifts and closer to that of the UV luminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from $\log_{10} \rho_{*} = 6.64^{+0.58}_{-0.89}$ at $z \sim 7$ to $7.36\pm0.06$ $\text{M}_{\odot} \text{Mpc}^{-3}$ at $z \sim 4$. Finally, combining the measured UV continuum slopes ($\beta$) with their rest-frame UV luminosities, we calculate dust corrected star-formation rates (SFR) for our sample. We find the specific star-formation rate for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.Comment: 28 pages, 23 figures, 2 appendices. Accepted for publication in MNRAS, August 7 201

The Lantern Vol. 17, No. 1, Fall 1948

• In the Arms of the Sea • The Expressed Should Be Repressed • Puppy Love • Tommy • How to Eat a Ravioli Dinner • The Divine Blessing • On Thunder • There Is No Hell • Old Love Re-met • Autumn Eve • Dr. Cornelius Weygandthttps://digitalcommons.ursinus.edu/lantern/1046/thumbnail.jp

The Lantern Vol. 17, No. 1, Fall 1948

• In the Arms of the Sea • The Expressed Should Be Repressed • Puppy Love • Tommy • How to Eat a Ravioli Dinner • The Divine Blessing • On Thunder • There Is No Hell • Old Love Re-met • Autumn Eve • Dr. Cornelius Weygandthttps://digitalcommons.ursinus.edu/lantern/1046/thumbnail.jp

The Lantern Vol. 15, No. 3, Summer 1947

• On Sleeping at Lectures • So You Want Security • Mild and Bitters • The Child April • Helgoland • His Majesty, Tabby • January Interval • A Friend or Two • Wish in June • The Search • Jack of 54 and Davey Jones • Song of the Earth • Donald Gay Baker • The Dilemma by the Horns • Psychologyhttps://digitalcommons.ursinus.edu/lantern/1042/thumbnail.jp

Comparison of Laboratory-Grade and Consumer-Grade Hand-to-Foot Bioelectrical Impedance Analyzers for Body Composition Estimation

Bioelectrical impedance analysis (BIA) is a simple and effective technique to estimate body composition, including body fat percentage (BFP). While these analyzers are a popular method of describing a person’s body composition, laboratory-grade devices are expensive and inaccessible to most people. As a result, they may be an unrealistic method for consumers to use. However, consumer-grade devices are increasingly available. PURPOSE: The purpose of this study was to compare laboratory-grade and consumer-grade bioelectrical impedance analyzers. METHODS: Seventy-five adults (40 F, 35 M) were evaluated using a laboratory-grade, hand-to-foot, multifrequency bioelectrical impedance analyzer (BIALAB; Seca mBCA 515) and a consumer-grade, hand-to-foot, single frequency bioelectrical impedance analyzer (BIACON; Omron HBF-516). Both devices administer undetectable electrical pulses through one extremity that are measured at another extremity, where the voltage drop (impedance) is determined. This information is used to estimate body fluids and composition. RESULTS: A strong, statistically significant correlation between devices was observed for BFP (r: 0.93, R2: 0.87, pCON overestimated BFP by 3.5 ± 3.4% (mean ± SD) relative to BIALAB (BIACON: 28.3 ± 9.6%; BIALAB: 24.8 ± 9.3%; pCONCLUSION: These results collectively suggest that while the laboratory-grade and consumer-grade analyzers in our study exhibit strong correlations when assessing a group of individuals, the consumer-grade device overestimates BFP. Additionally, the SEE indicates that 3.4% error can be expected with the consumer-grade device. Overall, the Omron HBF-516 consumer-grade device may be an adequate and affordable option to estimate body composition in some contexts, but results should be interpreted cautiously when used in individuals