998 research outputs found
Measurement of Holmium Rydberg series through MOT depletion spectroscopy
We report measurements of the absolute excitation frequencies of Ho
and odd-parity Rydberg series. The states are
detected through depletion of a magneto-optical trap via a two-photon
excitation scheme. Measurements of 162 Rydberg levels in the range
yield quantum defects well described by the Rydberg-Ritz formula. We observe a
strong perturbation in the series around due to an unidentified
interloper at 48515.47(4) cm. From the series convergence, we determine
the first ionization potential cm, which is
three orders of magnitude more accurate than previous work. This work
represents the first time such spectroscopy has been done in Holmium and is an
important step towards using Ho atoms for collective encoding of a quantum
register.Comment: 6 figure
PEACH PRICES IN CALIFORNIA IN THE PRESENCE OF TECHNOLOGICAL CHANGE IN THE AGRICULTURAL PESTICIDE INDUSTRY
The potentially adverse effects of pesticides in wide use are causing concern to grow in the agricultural community. Minimizing the risks to human health and the environment created by agricultural pesticides has become a very important issue. The United States Environmental Protection Agency (EPA) has set a high priority on registering safer pesticides. According to the EPA, more than 1 billion pounds of active pesticide ingredients are used in the United States each year. Americans are exposed to pesticides every day through food consumption, cleaning products, and home and work environments. The agricultural pesticide industry has experienced an influx of changes during the past decade. Two of the primary changes affecting the pesticide industry are the introduction of new technology and EPA regulatory changes. On the regulatory front, the EPA requires manufacturers to register and test pesticides before they appear on the market. By 2006, the EPA will review old pesticides to ensure that they meet new safety requirements. These regulatory initiatives have contributed to the industry drive to develop safer and more "environmentally friendly" products for use in agricultural pest control. Technological changes consist of the introduction of new pesticides that are considered to be safer for both humans and the environment. As new technologies and regulatory initiatives are undertaken to ensure an improvement in both the safety of human health and the environment, one must consider how these changes may affect consumers. Specifically, an analysis should be conducted to determine whether or not the technological and regulatory changes have an effect on consumer prices. The recent developments in the agricultural pesticide industry provide several reasons to believe structural change has been occurring in economic relationships that determine peach prices in California. Therefore, we use a vector autoregressive (VAR) model to forecast peach prices by allowing parameters to vary with time. VAR models differ from standard econometric analyses of structural relationships in that they do not apply the usual exclusion restrictions to specify a priori which variables appear in which equations. Instead, a set of distributed lag equations is used to model each variable as a function of other variables in the structural system (Bessler, 1984). The objective of this paper is to forecast peach prices and evaluate dynamic relationships in the peach industry in the presence of technological and regulatory change. A VAR model that explicitly recognizes structural change will be used to forecast peach prices in California. Changes in dynamic relationships between peach prices and relevant economic variables will be considered.Demand and Price Analysis,
A Pilot Study of Chronic Disease Self-Management in a Homeless Population
This pilot project developed, implemented, and evaluated the Stanford Chronic Disease Self-Management Program (CDSMP) with sheltered homeless adults (N=10). Participants demonstrated positive change in self-rated health, health distress, self-efficacy, exercise behaviors, and communication. The CDSMP may be effective with homeless clients if additional incentives are incorporated to overcome barriers to succes
Comparison of Sheep, Goats, and Calves as Infection Models for Mycobacterium avium subsp. paratuberculosis
Animal infection models to study Mycobacterium avium subsp. paratuberculosis (MAP) infection are useful for evaluating the efficacy of vaccines and other therapeutics for the prevention or treatment of infection. The goal of the present study was to compare smaller ruminants, sheep and goats, with calves as infection models. Neonatal sheep, goats, and calves (n = 4) received 109 cfu of a cattle isolate of MAP in milk replacer on days 0, 3 and 6 in a 12-month study and sampled monthly thereafter. Results demonstrated a robust antigen-specific IFN-γ response at 90 days post-inoculation for sheep and goats, with lower responses noted for calves. By 360 days, IFN-γ responses were 50 and 82% higher for calves than for goats and sheep, respectively. Although MAP- specific antibody responses were first observed in sheep at 90 days, calves had higher antibody responses throughout the remainder of the study. Following pass-through shedding on day 7, fecal shedding was fairly negligible across treatments but remained higher for calves throughout the study. Colonization of tissues was variable within treatment group and was higher for calves and sheep for the majority of tissues. Upon antigen stimulation of PBMCs, higher populations of CD4 + T cells cells and lower populations of γδ TCR + and NK cells were observed for goats and calves compared to sheep. Relative gene expression of IL-4, IL-12, and IL-17 in PBMCs was higher in goats, corresponding to lower tissue colonization with MAP. These data suggest that ruminant species are fairly comparable as infection models for MAP, but discrete differences in host responses to MAP infection exist between species
Disseminated \u3ci\u3eLeishmania infantum\u3c/i\u3e infection in two sibling foxhounds due to possible vertical transmission
Two sibling foxhounds born to a Leishmania seropositive bitch were presented after testing seropositive for Leishmania. Leishmania infantum infection was detected via histopathology, culture, and quantitative polymerase chain reaction (q-PCR). This is the first report of natural infection with Leishmania infantum with the possibility for vertical transmission in North America.
Infection disséminée à Leishmania infantum chez deux chiots Fox hound d’une même portée reliée possiblement à une transmission verticale. Deux chiots Fox hound d’une même portée nés d’une mère séropositive à Leishmania ont été présentés après un contrôle sérologique positif. Une infection à Leishmania infantum a été détectée par histopathologie, culture et amplification en chaîne par polymérase quantitative (ACP-q). Il s’agit du premier rapport d’infection naturelle par Leishmania infantum possiblement relié à une transmission verticale en Amérique du Nord
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Susceptibility of juvenile salmonids to avian predation : Are Caspian terns and double-crested cormorants only taking the sick and injured?
The ability to non-destructively assess fish condition and subsequently track fish behavior and survival can be vital in understanding natural and anthropogenic stressors and sources of mortality, especially in populations of fish listed as threatened or endangered. I investigated the use of a quick, non-lethal, external examination technique to assess general health status of run-of-the-river juvenile steelhead (Oncorhynchus mykiss) migrating from the Snake River basin.
The relationship between external symptoms of captured fish (including body injuries, de-scaling, external symptoms of disease, fin damage, and ectoparasite infestations) and their health status was investigated through pathology analysis of a euthanized subsample of fish. I assessed the relative fitness of steelhead smolts assigned to various categories of health status by measuring the subsequent survival and susceptibility to avian predation of fish that were tagged with passive integrated transponder (PIT) tags and released unharmed. Histological analysis was conducted on 222 steelhead sacrificed at the juvenile collection facility of Lower Monumental Dam (LMN) on the lower Snake River during steelhead out-migration in 2008; results indicated that external symptoms of disease, body injuries, de-scaling, and fin damage were all associated with increased prevalence of infectious pathogens.
Capture-recapture models for 14,177 steelhead PIT-tagged and released at LMN in 2007 and 2008 indicated that the presence of external symptoms of disease, body injuries, or de-scaling, but not fin damage, were associated with significantly reduced survival probabilities during either short-distance (ca. 119 Rkm) or long-distance (ca. 354 Rkm) migration. PIT tags from 3.0% and 1.9% of all released steelhead (n = 16,258) were recovered on a Caspian tern (Hydroprogne caspia) colony and a double-crested cormorant (Phalacrocorax auritus) colony, respectively, located < 79 Rkm downstream of release locations. A consistent factor relating susceptibility of steelhead to predation by both bird species was compromised health, particularly steelhead with external symptoms of disease and body injuries. River conditions, including decreased discharge and elevated water temperatures at the time of release, were also associated with increased susceptibility of steelhead to avian predation, but the strength of these explanatory factors differed between species of avian predator.
These results support the conclusion that external condition, measured non-destructively on individual fish, is associated with quantifiable differences in general health status and fitness of fish. Results also indicate that some reduction in avian predation on juvenile salmonids (Oncorhynchus spp.) may be accomplished by modifying hydrosystem operations. The higher susceptibility of unhealthy steelhead to avian predation suggests that a portion of any reduction in mortality due to avian predation will be compensated for by other sources of smolt mortality. The portion of juvenile steelhead that are at greater risk of avian predation is small, however, based on the small proportion of steelhead that exhibited visible symptoms of compromised health
JITB : a back end for just-in-time compilers
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 56-57).by Mathew J. Hostetter.M.Eng
Quantification of Macrophages and Mycobacterium avium Subsp. paratuberculosis in Bovine Intestinal Tissue During Different Stages of Johne’s Disease
Johne’s disease is an enteric disease caused by the intracellular pathogen Mycobacterium avium subsp. paratuberculosis (MAP). Upon ingestion of MAP, it is translocated across the intestinal epithelium and may be killed by intestinal macrophages, or depending on the bacterial burden and immunological status of the animal, MAP may thwart innate defense mechanisms and persist within the macrophage. This study aimed to determine the numbers of macrophages and MAP present in bovine midileal tissue during different stages of infection. Immunofluorescent (IF) labeling was performed on frozen bovine midileal intestinal tissue collected from 28 Holstein dairy cows. The number of macrophages in midileal tissue sections was higher for clinically affected cows, followed by subclinically affected cows and then uninfected control cows. Macrophages were present throughout the tissue sections in clinical cows, including the tunica muscularis, submucosa, and the lamina propria around the crypts and in the villous tips, with progressively fewer macrophages in subclinically affected and control cows. Clinically affected cows also demonstrated significantly higher numbers of MAP and higher numbers of macrophages with intracellular MAP compared to subclinically affected cows. MAP IF labeling was present within the submucosa and lamina propria around the crypts, progressing into the villous tips in some clinically affected cows. Our findings indicate that number of macrophages increases with progression of infection, but a significant number of the macrophages present in the midileum are not associated with MAP
Creation and Curation of the Society of Imaging Informatics in Medicine Hackathon Dataset
In order to support innovation, the Society of Imaging Informatics in Medicine (SIIM) elected to create a collaborative computing experience called a "hackathon." The SIIM Hackathon has always consisted of two components, the event itself and the infrastructure and resources provided to the participants. In 2014, SIIM provided a collection of servers to participants during the annual meeting. After initial server setup, it was clear that clinical and imaging "test" data were also needed in order to create useful applications. We outline the goals, thought process, and execution behind the creation and maintenance of the clinical and imaging data used to create DICOM and FHIR Hackathon resources
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