605 research outputs found
SUIZA FOODS CORPORATION: BEST MANAGEMENT STRATEGY IN THE FLUID MILK INDUSTRY
Suiza Foods has rapidly grown to become the largest company in the U.S. fluid milk industry. This teaching case is designed to familiarize students with the challenges which confront Suiza in its quest for further growth and, in turn, high profitability. Interviews with top executives describe the history of Suiza as well as the rationale behind Suiza's strategies. Information is presented on both economic and financial trends so as to allow the student to asses Suiza's past, present and future performance.Agribusiness, Livestock Production/Industries,
Study protocol for a randomised pilot study of a computer-based, non-pharmacological cognitive intervention for motor slowing and motor fatigue in Parkinson’s disease
High-Velocity Line Forming Regions in the Type Ia Supernova 2009ig
We report measurements and analysis of high-velocity (> 20,000 km/s) and
photospheric absorption features in a series of spectra of the Type Ia
supernova (SN) 2009ig obtained between -14d and +13d with respect to the time
of maximum B-band luminosity. We identify lines of Si II, Si III, S II, Ca II
and Fe II that produce both high-velocity (HVF) and photospheric-velocity (PVF)
absorption features. SN 2009ig is unusual for the large number of lines with
detectable HVF in the spectra, but the light-curve parameters correspond to a
slightly overluminous but unexceptional SN Ia (M_B = -19.46 mag and Delta_m15
(B) = 0.90 mag). Similarly, the Si II lambda_6355 velocity at the time of B-max
is greater than "normal" for a SN Ia, but it is not extreme (v_Si = 13,400
km/s). The -14d and -13d spectra clearly resolve HVF from Si II lambda_6355 as
separate absorptions from a detached line forming region. At these very early
phases, detached HVF are prevalent in all lines. From -12d to -6d, HVF and PVF
are detected simultaneously, and the two line forming regions maintain a
constant separation of about 8,000 km/s. After -6d all absorption features are
PVF. The observations of SN 2009ig provide a complete picture of the transition
from HVF to PVF. Most SN Ia show evidence for HVF from multiple lines in
spectra obtained before -10d, and we compare the spectra of SN 2009ig to
observations of other SN. We show that each of the unusual line profiles for Si
II lambda_6355 found in early-time spectra of SN Ia correlate to a specific
phase in a common development sequence from HVF to PVF.Comment: 19 pages, 11figures, 4 tables, submitted to Ap
The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet
We examine the absolute magnitudes and light-curve shapes of 14
nearby(redshift z = 0.004--0.027) Type Ia supernovae (SNe~Ia) observed in the
ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and
absolute magnitudes are calculated using both a standard Milky Way (MW)
extinction law and one for the Large Magellanic Cloud that has been modified by
circumstellar scattering. We find very different behavior in the near-UV
filters (uvw1_rc covering ~2600-3300 A after removing optical light, and u
~3000--4000 A) compared to a mid-UV filter (uvm2 ~2000-2400 A). The uvw1_rc-b
colors show a scatter of ~0.3 mag while uvm2-b scatters by nearly 0.9 mag.
Similarly, while the scatter in colors between neighboring filters is small in
the optical and somewhat larger in the near-UV, the large scatter in the
uvm2-uvw1 colors implies significantly larger spectral variability below 2600
A. We find that in the near-UV the absolute magnitudes at peak brightness of
normal SNe Ia in our sample are correlated with the optical decay rate with a
scatter of 0.4 mag, comparable to that found for the optical in our sample.
However, in the mid-UV the scatter is larger, ~1 mag, possibly indicating
differences in metallicity. We find no strong correlation between either the UV
light-curve shapes or the UV colors and the UV absolute magnitudes. With larger
samples, the UV luminosity might be useful as an additional constraint to help
determine distance, extinction, and metallicity in order to improve the utility
of SNe Ia as standardized candles.Comment: 59 pages, accepted for publication in Ap
Non-linear regression models for Approximate Bayesian Computation
Approximate Bayesian inference on the basis of summary statistics is
well-suited to complex problems for which the likelihood is either
mathematically or computationally intractable. However the methods that use
rejection suffer from the curse of dimensionality when the number of summary
statistics is increased. Here we propose a machine-learning approach to the
estimation of the posterior density by introducing two innovations. The new
method fits a nonlinear conditional heteroscedastic regression of the parameter
on the summary statistics, and then adaptively improves estimation using
importance sampling. The new algorithm is compared to the state-of-the-art
approximate Bayesian methods, and achieves considerable reduction of the
computational burden in two examples of inference in statistical genetics and
in a queueing model.Comment: 4 figures; version 3 minor changes; to appear in Statistics and
Computin
Surgical therapy for peri-implantitis management: a systematic review and meta-analysis
Aim
Peri‐implantitis is a common cause of late implant failure. Studies have investigated different treatment strategies. The effectiveness of these modalities, however, remains unclear. This study aimed to evaluate the success of surgical peri‐implantitis treatment using clinical and radiographic parameters.
Material and methods
A systematic review of published literature was employed. Key words were selected to conduct an electronic search using four databases for literature on human clinical studies. Meta‐analyses were carried out for clinical probing, pocket depth and radiographic bone level.
Results
A total of 16 papers met the inclusion criteria. Four treatment modalities to supplement mechanical debridement were identified: (i) apically repositioned flap, (ii) chemical surface decontamination, (iii) implantoplasty, and (iv) bone augmentation. Inconsistent results were evident which were dependent on several treatment‐independent factors. No clinical benefits were identified for the additional use of surface decontamination, while limited evidence demonstrated improvement of clinical and radiographic outcomes after implantoplasty. The effect of bone augmentation appeared limited to ‘filling’ radiographic defects.
Conclusions
The outcomes of the currently available surgical interventions for peri‐implantitis remain unpredictable. There is no reliable evidence to suggest which methods are the most effective. Further randomised‐controlled studies are needed to identify the best treatment methods
Preliminary genetic evidence of two different populations of Opisthorchis viverrini in Lao PDR
Opisthorchis viverrini is a major public health concern in Southeast Asia. Various reports have suggested that this parasite may represent a species complex, with genetic structure in the region perhaps being dictated by geographical factors and different species of intermediate hosts. We used four microsatellite loci to analyze O. viverrini adult worms originating from six species of cyprinid fish in Thailand and Lao PDR. Two distinct O. viverrini populations were observed. In Ban Phai, Thailand, only one subgroup occurred, hosted by two different fish species. Both subgroups occurred in fish from That Luang, Lao PDR, but were represented to very different degrees among the fish hosts there. Our data suggest that, although geographical separation is more important than fish host specificity in influencing genetic structure, it is possible that two species of Opisthorchis, with little interbreeding, are present near Vientiane in Lao PDR
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