16,357 research outputs found
New phenomena in the standard no-scale supergravity model
We revisit the no-scale mechanism in the context of the simplest no-scale
supergravity extension of the Standard Model. This model has the usual
five-dimensional parameter space plus an additional parameter . We show how predictions of the model may be extracted over
the whole parameter space. A necessary condition for the potential to be stable
is , which is satisfied if \bf m_{3/2}\lsim2 m_{\tilde
q}. Order of magnitude calculations reveal a no-lose theorem guaranteeing
interesting and potentially observable new phenomena in the neutral scalar
sector of the theory which would constitute a ``smoking gun'' of the no-scale
mechanism. This new phenomenology is model-independent and divides into three
scenarios, depending on the ratio of the weak scale to the vev at the minimum
of the no-scale direction. We also calculate the residual vacuum energy at the
unification scale (), and find that in typical models one must
require . Such constraints should be important in the search for the
correct string no-scale supergravity model. We also show how specific classes
of string models fit within this framework.Comment: 11pages, LaTeX, 1 figure (included), CERN-TH.7433/9
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Scientific drilling of the Boltysh impact crater, Ukraine
Introduction: The Boltysh crater has been known for several decades and was first drilled in the 1960s as part of a study of economic oil shale deposits. Unfortunately, the cores were not curated and have been lost. We have re-drilled the impact crater and have recovered a near continuous record of ~400 m of organicrich sediments together with 15 m of suevite
An exploratory flight investigation of helicopter sling-load placements using a closed-circuit television as a pilot aid
Helicopter sling load operations have been limited during pick up and delivery of external cargo by the lack of precision achieved by the combination of pilot, helicopter, and sling load. Use of a closed circuit television as a pilot aid during sling load delivery and placement was documented along with additional cases representing procedures currently employed by military and commercial operators. Although an increase in pilot workload was noted when the television system was used, the results indicated a comparable level of performance for each test case
Ovalbumin sensitization and challenge increases the number of lung cells possessing a mesenchymal stromal cell phenotype
Abstract Background Recent studies have indicated the presence of multipotent mesenchymal stromal cells (MSCs) in human lung diseases. Excess airway smooth muscle, myofibroblasts and activated fibroblasts have each been noted in asthma, suggesting that mesenchymal progenitor cells play a role in asthma pathogenesis. We therefore sought to determine whether MSCs are present in the lungs of ovalbumin (OVA)-sensitized and challenged mice, a model of allergic airways disease. Methods Balb/c mice were sensitized and challenged with PBS or OVA over a 25 day period. Flow cytometry as well as colony forming and differentiation potential were used to analyze the emergence of MSCs along with gene expression studies using immunochemical analyses, quantitative polymerase chain reaction (qPCR), and gene expression beadchips. Results A CD45-negative subset of cells expressed Stro-1, Sca-1, CD73 and CD105. Selection for these markers and negative selection against CD45 yielded a population of cells capable of adipogenic, osteogenic and chondrogenic differentiation. Lungs from OVA-treated mice demonstrated a greater average colony forming unit-fibroblast (CFU-F) than control mice. Sorted cells differed from unsorted lung adherent cells, exhibiting a pattern of gene expression nearly identical to bone marrow-derived sorted cells. Finally, cells isolated from the bronchoalveolar lavage of a human asthma patient showed identical patterns of cell surface markers and differentiation potential. Conclusions In summary, allergen sensitization and challenge is accompanied by an increase of MSCs resident in the lungs that may regulate inflammatory and fibrotic responses.http://deepblue.lib.umich.edu/bitstream/2027.42/78265/1/1465-9921-11-127.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/2/1465-9921-11-127.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/3/1465-9921-11-127-S1.DOCPeer Reviewe
Arkansas Wheat Cultivar Performance Tests 2018-2019
Wheat cultivar performance tests are conducted each year in Ark- ansas by the University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers. The tests are conducted at the Northeast Research and Extension Center at Keiser, the Vegetable Substation near Kibler, the Lon Mann Cotton Research Station near Marianna, the Newport Extension Center near Newport, the Rohwer Research Station near Rohwer, the Pine Tree Research Station near Colt, and the Hope Research and Extension Center. In addition, entries are evaluated in a stripe rust (Puccinia striiformis f.sp. tritici) inoculated nursery in Fayetteville and a Fusarium head blight (FHB) inoculated nursery in Newport and Fayetteville. Specific location and cultural practice information accompany each table
Arkansas Wheat Cultivar Performance Tests 2016-2017
Wheat cultivar performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers
Quinine blocks 5-HT and 5-HT3 receptor mediated peristalsis in both guinea pig and mouse ileum tissue
Introduction. Quinine is commonly used to treat malaria; however one of the principal side effects is gastrointestinal disturbances (White, 1992). 5-HT3 receptors modulate gut peristalsis (Chetty et al., 2006), and, as quinine has been shown to act as a 5-HT3 receptor antagonist (Thompson and Lummis, 2008) it is possible that these side effects result from actions at gut 5-HT3 receptors. To address this question, we examined the ability of quinine to antagonise 5-HT and 5-HT3 mediated peristalsis in guinea pig and mouse ileum.
Methods. Ileum was excised from male guinea pigs (200-300g) and C57BL/6 mice (25-35g) following cervical dislocation. Ileum segments (3-5 cm) were mounted in 50 ml organ baths containing Tryode’s solution at 35-37 °C. Concentration-response curves were constructed for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT (non-cumulative doses). Quinine was pre-applied for 10 min and inhibition measured using agonist concentrations that elicited a submaximal response.
Results. Concentration-dependent contractions produced by 5-HT (pEC50 = 5.45 ± 0.17, n = 8) and the selective 5-HT3 agonist 2-Me-5-HT (5.01 ± 0.17, n = 11) were not significantly different (Student’s t-test, t = 0.619, df = 17, p = 0.544) in guinea pig ileum. Increasing concentrations of quinine were able to antagonise the activities of both 5-HT (pIC50 = 5.03 ± 0.2, n = 6) and 2-Me-5HT (pIC50 = 4.59 ± 0.26, n = 4). At mouse ileum, 5-HT (pEC50 = 7.57 ± 0.33, n = 9) was more potent (Student’s t-test, t = 3.6, df = 12, p = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5). Quinine antagonised both the 5-HT (pIC50 = 4.87 ± 0.31, n = 7) and 2-Me-5-HT-induced (pIC50 = 6.18 ± 1.14, n = 4) contractions.
Conclusions. These results support previous electrophysiological studies that identified quinine as an antagonist at recombinant 5-HT3 receptors with IC50 values comparable with those reported here (pIC50 = 4.87, Thompson et al., 2007). Further, we found that quinine completely blocked 5-HT induced contractions in mouse and guinea pig, raising the possibility that quinine targets other 5-HT receptors in the gut (e.g., 5-HT4 receptors) and may influence intestinal function
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