88 research outputs found
Design of University Small-Scale Dairy Processing Facility
This project was assigned to research the feasibility and value of implementing a dairy processing facility on the campus of the University of Nebraska-Lincoln. The facility would process milk produced from cows under the same roof and will serve as an educational experience for Nebraska dairy farmers, UNL students, and K-12 students in the Lincoln-Lancaster County area. If the project is successful and replicated across the state, this facility could have a significant impact on the reduction of milk transportation costs in the Nebraska dairy industry.
The project began with researching milk processing methods and steps from production to consumption. Shortly after this step, information on milk consumption patterns was collected from UNL Dining Services to determine demand on campus. Every unit operation requires certain equipment to effectively ensure the safety and quality of the final product, and mass balances from UNL milk consumption data were used to size equipment and storage capacity. Engineering firms were then consulted to gather information on equipment specifications and prices. Equipment costs and operating costs (estimated with the help of Dr. Howell and other university dairy operations) were entered into a Monte Carlo simulation to analyze return on investment and a breakeven point.
The results from the costs section showed that the fixed costs (equipment and engineering) for the milk processing would be about $1.2 million. The Monte Carlo simulation showed that the project would not turn a profit for 10-12 years, and approximately 2.25 million gallons of milk would need to be processed and sold to recover initial costs. Overall, the project successfully displays data that can be interpreted by the client to decide whether to move forward with the project and the appropriate scale for the project at UNL
Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z~2 III: Far-IR to Radio Properties and Optical Spectral Diagnostics
We present the far-IR, millimeter, and radio photometry as well as optical
and near-IR spectroscopy of a sample of 48 z~1-3 Spitzer-selected ULIRGs with
IRS mid-IR spectra. Our goals are to compute their bolometric emission, and to
determine both the presence and relative strength of their AGN and starburst
components. We find that strong-PAH sources tend to have higher 160um and 1.2mm
fluxes than weak-PAH sources. The depth of the 9.7um silicate feature does not
affect MAMBO detectability. We fit the far-IR SEDs of our sample and find an
average ~7x10^{12}Lsun for our z>1.5 sources. Spectral decomposition
suggests that strong-PAH sources typically have ~20-30% AGN fractions. Weak-PAH
sources by contrast tend to have >~70% AGN fractions, with a few sources having
comparable contributions of AGN and starbursts. The optical line diagnostics
support the presence of AGN in the bulk of the weak-PAH sources. With one
exception, our sources are narrow-line sources, show no obvious correspondence
between the optical extinction and the silicate feature depth, and, in two
cases, show evidence for outflows. Radio AGN are present in both strong-PAH and
weak-PAH sources. This is supported by our sample's far-IR-to-radio ratios (q)
being consistently below the average value of 2.34 for local star-forming
galaxies. We use survival analysis to include the lower-limits given by the
radio-undetected sources, arriving at =2.07+/-0.01 for our z>1.5 sample. In
total, radio and, where available, optical line diagnostics support the
presence of AGN in 57% of the z>1.5 sources, independent of IR-based
diagnostics. For higher-z sources, the AGN luminosities alone are estimated to
be >10^{12}Lsun, which, supported by the [OIII] luminosities, implies that the
bulk of our sources host obscured quasars.Comment: 22 pages, 14 figures, accepted for publication in Ap
An evolutionary and structural characterization of mammalian protein complex organization
Background: We have recently released a comprehensive, manually curated database of mammalian protein complexes called CORUM. Combining CORUM with other resources, we assembled a dataset of over 2700 mammalian complexes. The availability of a rich information resource allows us to search for organizational properties concerning these complexes. Results: As the complexity of a protein complex in terms of the number of unique subunits increases, we observed that the number of such complexes and the mean non-synonymous to synonymous substitution ratio of associated genes tend to decrease. Similarly, as the number of different complexes a given protein participates in increases, the number of such proteins and the substitution ratio of the associated gene also tend to decrease. These observations provide evidence relating natural selection and the organization of mammalian complexes. We also observed greater homogeneity in terms of predicted protein isoelectric points, secondary structure and substitution ratio in annotated versus randomly generated complexes. A large proportion of the protein content and interactions in the complexes could be predicted from known binary protein-protein and domain-domain interactions. In particular, we found that large proteins interact preferentially with much smaller proteins. Conclusions: We observed similar trends in yeast and other data. Our results support the existence of conserved relations associated with the mammalian protein complexes
BLAST05: Power Spectra of Bright Galactic Cirrus at Submillimeter Wavelengths
We report multi-wavelength power spectra of diffuse Galactic dust emission
from BLAST observations at 250, 350, and 500 microns in Galactic Plane fields
in Cygnus X and Aquila. These submillimeter power spectra statistically
quantify the self-similar structure observable over a broad range of scales and
can be used to assess the cirrus noise which limits the detection of faint
point sources. The advent of submillimeter surveys with the Herschel Space
Observatory makes the wavelength dependence a matter of interest. We show that
the observed relative amplitudes of the power spectra can be related through a
spectral energy distribution (SED). Fitting a simple modified black body to
this SED, we find the dust temperature in Cygnus X to be 19.9 +/- 1.3 K and in
the Aquila region 16.9 +/- 0.7 K. Our empirical estimates provide important new
insight into the substantial cirrus noise that will be encountered in
forthcoming observations.Comment: Submitted to the Astrophysical Journal. Maps and other data are
available at http://blastexperiment.info
A panchromatic study of BLAST counterparts: total star-formation rate, morphology, AGN fraction and stellar mass
We carry out a multi-wavelength study of individual galaxies detected by the
Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at
other wavelengths, using data spanning the radio to the ultraviolet (UV). We
develop a Monte Carlo method to account for flux boosting, source blending, and
correlations among bands, which we use to derive deboosted far-infrared (FIR)
luminosities for our sample. We estimate total star-formation rates for BLAST
counterparts with z < 0.9 by combining their FIR and UV luminosities. Star
formation is heavily obscured at L_FIR > 10^11 L_sun, z > 0.5, but the
contribution from unobscured starlight cannot be neglected at L_FIR < 10^11
L_sun, z < 0.25. We assess that about 20% of the galaxies in our sample show
indication of a type-1 active galactic nucleus (AGN), but their submillimeter
emission is mainly due to star formation in the host galaxy. We compute stellar
masses for a subset of 92 BLAST counterparts; these are relatively massive
objects, with a median mass of ~10^11 M_sun, which seem to link the 24um and
SCUBA populations, in terms of both stellar mass and star-formation activity.
The bulk of the BLAST counterparts at z<1 appear to be run-of-the-mill
star-forming galaxies, typically spiral in shape, with intermediate stellar
masses and practically constant specific star-formation rates. On the other
hand, the high-z tail of the BLAST counterparts significantly overlaps with the
SCUBA population, in terms of both star-formation rates and stellar masses,
with observed trends of specific star-formation rate that support strong
evolution and downsizing.Comment: Accepted for publication in the Astrophysical Journal. 44 pages, 11
figures. The SED template for the derivation of L_FIR has changed (added new
figure) and the discussion on the stellar masses has been improved. The
complete set of full-color postage-stamps can be found at
http://blastexperiment.info/results_images/moncelsi
Observations of Arp 220 using Herschel-SPIRE: An Unprecedented View of the Molecular Gas in an Extreme Star Formation Environment
We present Herschel SPIRE-FTS observations of Arp~220, a nearby ULIRG. The
FTS continuously covers 190 -- 670 microns, providing a good measurement of the
continuum and detection of several molecular and atomic species. We detect
luminous CO (J = 4-3 to 13-12) and water ladders with comparable total
luminosity; very high-J HCN absorption; OH+, H2O+, and HF in absorption; and CI
and NII. Modeling of the continuum yields warm dust, with T = 66 K, and an
unusually large optical depth of ~5 at 100 microns. Non-LTE modeling of the CO
shows two temperature components: cold molecular gas at T ~ 50 K and warm
molecular gas at T ~1350 K. The mass of the warm gas is 10% of the cold gas,
but dominates the luminosity of the CO ladder. The temperature of the warm gas
is in excellent agreement with H2 rotational lines. At 1350 K, H2 dominates the
cooling (~20 L_sun/M_sun) in the ISM compared to CO (~0.4 L_sun/M_sun). We
found that only a non-ionizing source such as the mechanical energy from
supernovae and stellar winds can excite the warm gas and satisfy the energy
budget of ~20 L_sun/M_sun. We detect a massive molecular outflow in Arp 220
from the analysis of strong P-Cygni line profiles observed in OH+, H2O+, and
H2O. The outflow has a mass > 10^{7} M_sun and is bound to the nuclei with
velocity < 250 km/s. The large column densities observed for these molecular
ions strongly favor the existence of an X-ray luminous AGN (10^{44} ergs/s) in
Arp 220.Comment: Accepted in ApJ on September 1, 201
Definition of the viral targets of protective HIV-1-specific T cell responses
<p>Abstract</p> <p>Background</p> <p>The efficacy of the CTL component of a future HIV-1 vaccine will depend on the induction of responses with the most potent antiviral activity and broad HLA class I restriction. However, current HIV vaccine designs are largely based on viral sequence alignments only, not incorporating experimental data on T cell function and specificity.</p> <p>Methods</p> <p>Here, 950 untreated HIV-1 clade B or -C infected individuals were tested for responses to sets of 410 overlapping peptides (OLP) spanning the entire HIV-1 proteome. For each OLP, a "protective ratio" (PR) was calculated as the ratio of median viral loads (VL) between OLP non-responders and responders.</p> <p>Results</p> <p>For both clades, there was a negative relationship between the PR and the entropy of the OLP sequence. There was also a significant additive effect of multiple responses to beneficial OLP. Responses to beneficial OLP were of significantly higher functional avidity than responses to non-beneficial OLP. They also had superior in-vitro antiviral activities and, importantly, were at least as predictive of individuals' viral loads than their HLA class I genotypes.</p> <p>Conclusions</p> <p>The data thus identify immunogen sequence candidates for HIV and provide an approach for T cell immunogen design applicable to other viral infections.</p
BLAST: A Far-Infrared Measurement of the History of Star Formation
We directly measure redshift evolution in the mean physical properties
(far-infrared luminosity, temperature, and mass) of the galaxies that produce
the cosmic infrared background (CIB), using measurements from the Balloon-borne
Large Aperture Sub-millimeter Telescope (BLAST), and Spitzer which constrain
the CIB emission peak. This sample is known to produce a surface brightness in
the BLAST bands consistent with the full CIB, and photometric redshifts are
identified for all of the objects. We find that most of the 70 micron
background is generated at z <~ 1 and the 500 micron background generated at z
>~ 1. A significant growth is observed in the mean luminosity from ~ 10^9 -
10^12 L_sun, and in the mean temperature by 10 K, from redshifts 0< z < 3.
However, there is only weak positive evolution in the comoving dust mass in
these galaxies across the same redshift range. We also measure the evolution of
the far-infrared luminosity density, and the star-formation rate history for
these objects, finding good agreement with other infrared studies up to z ~1,
exceeding the contribution attributed to optically-selected galaxies.Comment: Accepted for publication in the Astrophysical Journal. Maps available
at http://blastexperiment.info
Evidence for Environmental Changes in the Submillimeter Dust Opacity
The submillimeter opacity of dust in the diffuse Galactic interstellar medium
(ISM) has been quantified using a pixel-by-pixel correlation of images of
continuum emission with a proxy for column density. We used three BLAST bands
at 250, 350, and 500 \mu m and one IRAS at 100 \mu m. The proxy is the
near-infrared color excess, E(J-Ks), obtained from 2MASS. Based on observations
of stars, we show how well this color excess is correlated with the total
hydrogen column density for regions of moderate extinction. The ratio of
emission to column density, the emissivity, is then known from the
correlations, as a function of frequency. The spectral distribution of this
emissivity can be fit by a modified blackbody, whence the characteristic dust
temperature T and the desired opacity \sigma_e(1200) at 1200 GHz can be
obtained. We have analyzed 14 regions near the Galactic plane toward the Vela
molecular cloud, mostly selected to avoid regions of high column density (N_H >
10^{22} cm^-2) and small enough to ensure a uniform T. We find \sigma_e(1200)
is typically 2 to 4 x 10^{-25} cm^2/H and thus about 2 to 4 times larger than
the average value in the local high Galactic latitude diffuse atomic ISM. This
is strong evidence for grain evolution. There is a range in total power per H
nucleon absorbed (re-radiated) by the dust, reflecting changes in the
interstellar radiation field and/or the dust absorption opacity. These changes
affect the equilibrium T, which is typically 15 K, colder than at high
latitudes. Our analysis extends, to higher opacity and lower T, the trend of
increasing opacity with decreasing T that was found at high latitudes. The
recognition of changes in the emission opacity raises a cautionary flag because
all column densities deduced from dust emission maps, and the masses of compact
structures within them, depend inversely on the value adopted.Comment: Original version (22 Dec 2011): 14 pages, 8 figures. Revised version
(24 February 2012) accepted for publication in the Astrophysical Journal (14
March 2012): elaborated details of analysis, extended discussion including
new Appendix; abstract, results, conclusions unchanged. 16 pages, 9 figure
Initial conditions for star formation in clusters: physical and kinematical structure of the starless core Oph A-N6
We present high spatial (<300 AU) and spectral (0.07 km/s) resolution
Submillimeter Array observations of the dense starless cluster core Oph A-N6,
in the 1 mm dust continuum and the 3-2 line of N2H+ and N2D+. The dust
continuum observations reveal a compact source not seen in single-dish
observations, of size ~1000 AU and mass 0.005-0.01 M\odot. The combined line
and single-dish observations reveal a core of size 3000 \times 1400 AU
elongated in a NW-SE direction, with almost no variation in either line width
or line center velocity across the map, and very small non-thermal motions. The
deuterium fraction has a peak value of ~0.15 and is >0.05 over much of the
core. The N2H+ column density profile across the major axis of Oph A-N6 is well
represented by an isothermal cylinder, with temperature 20 K, peak density 7.1
\times 10^6 cm^{-3}, and N2H+ abundance 2.7 \times 10^{-10}. The mass of Oph
A-N6 is estimated to be 0.29 M\odot, compared to a value of 0.18 M\odot from
the isothermal cylinder analysis, and 0.63 M\odot for the critical mass for
fragmentation of an isothermal cylinder. Compared to isolated low-mass cores,
Oph A-N6 shows similar narrow line widths and small velocity variation, with a
deuterium fraction similar to "evolved" dense cores. It is significantly
smaller than isolated cores, with larger peak column and volume density. The
available evidence suggests Oph A-N6 has formed through the fragmentation of
the Oph A filament and is the precursor to a low-mass star. The dust continuum
emission suggests it may already have begun to form a star.Comment: 42 pages, 12 figures, accepted by Ap
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