45,050 research outputs found
Determinants of Studentsâ First Impressions of Instructors and Courses
Students evaluated instructors and courses in the first two weeks of the fall semester to determine the factors that form impressions in the early stages of the semester. Results indicate differences exist between upper and lower division courses with presentation of material and perceived workload as key factors that students use to form first impressions.Teaching/Communication/Extension/Profession,
On the 2-categories of weak distributive laws
A weak mixed distributive law (also called weak entwining structure) in a
2-category consists of a monad and a comonad, together with a 2-cell relating
them in a way which generalizes a mixed distributive law due to Beck. We show
that a weak mixed distributive law can be described as a compatible pair of a
monad and a comonad, in 2-categories extending, respectively, the 2-category of
comonads and the 2-category of monads. Based on this observation, we define a
2-category whose 0-cells are weak mixed distributive laws. In a 2-category K
which admits Eilenberg-Moore constructions both for monads and comonads, and in
which idempotent 2-cells split, we construct a fully faithful 2-functor from
this 2-category of weak mixed distributive laws to K^{2 x 2}.Comment: 15 pages LaTeX source, final version to appear in Comm. Algebr
Survival and Growth of American Alligator (Alligator mississippiensis) hatchlings after artificial incubation and repatriation
Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated
wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and
repatriated hatchlings released within and outside the maternal alligatorâs home range with naturally
incubated hatchlings captured and released within the maternal alligatorâs home range on Lake Apopka,
Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately
nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released
outside of the maternal alligatorâs home range had lower recapture probabilities than either naturally
incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture
probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were
approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching.
We concluded that repatriation of hatchlings probably would not have long-term effects on populations
because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of
the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation
of older juveniles for population restoration. However, the location of release may affect subsequent survival
and growth
The Design of Pumpjets for Hydrodynamic Propulsion
A procedure for use in the design of a wake adapted pumpjet mounted on the aft end of a body of revolution is presented. To this end, a pumpjet is designed for the Akron airship. The propulsor mass flow is selected to minimize kinetic energy losses through the duct and in the discharge jet. The shaft speed and disk size are selected to satisfy specified limits of cavitation performance and to provide acceptable blade loading. The streamtubes which pass through a propulsor mounted on a tapered afterbody follow essentially conical surfaces. A method is provided for defining these surfaces as a function of shroud geometry, rotor head distribution, and the energy distribution of the ingested mass flow. The three-dimensional effects to which the conical flow subjects the cylindrical blade design sections are described and a technique is presented which permits incorporation of these effects in the blade design procedure
Berseem Clover in Binary Mixtures with Oats, Triticale or Barley for Silage and Late Season Grazing
An experiment was conducted at northerly latitudes with berseem clover (Trifolium alexandrinum L) in binary mixtures with oats (Avena sativa L.), barley (Hordeum vulgare L.) and triticale (X Triticosecale Wittmack). The effects of cereal species, variety and density were assessed for a two cut harvest. Total dry matter yields were 11.7 to 14.5 t ha-1, with 7.8 to 10.2 t ha-1 as silage, and 2.0 to 6.0 t ha-1 as berseem regrowth. Berseem regrowth added an average of 4.0 t ha-1 in forage yield. Total yields did not differ with cereal type, but triticale mixtures had higher silage yields and lower regrowth yields than the other cereals. The silage yield of the Œ triticale mixture had the best combination of high yield (10.2 t ha-1) and high berseem component (23%). Early maturity of the barley allowed for a longer period of regrowth. The full rate of cereals was too competitive and greatly suppressed berseem initial growth and regrowth. Reducing the cereal density to Œ of the full rate, increased the percentage of berseem in yields, and increased the total yields of barley, AC Mustang oat and triticale mixtures. Intercropping of berseem clover with silage cereals shows promise as a means to extend the grazing season and increase total forage yields
Mifepristone reduces insulin resistance in patient volunteers with adrenal incidentalomas that secrete low levels of cortisol : a pilot study
Background: Incidental adrenal masses are commonly detected during imaging for other pathologies. 10% of the elderly
population has an âadrenal incidentalomaâ, up to 20% of these show low-grade autonomous cortisol secretion and 60% of
patients with autonomous cortisol secretion have insulin resistance. Cortisol excess is known to cause insulin resistance, an
independent cardiovascular risk marker, however in patients with adrenal incidentalomas it is unknown whether their
insulin resistance is secondary to the excess cortisol and therefore potentially reversible. In a proof of concept study we
examined the short-term effects of glucocorticoid receptor (GR) antagonism in patients with an adrenal incidentaloma to
determine whether their insulin resistance was reversible.
Methodology/Principal Findings: In a prospective open-label pilot study, six individuals with adrenal incidentalomas and
autonomous cortisol secretion were treated with mifepristone (a GR antagonist) 200 mg twice daily and studied for 4 weeks
on a Clinical Research Facility. Insulin resistance at four weeks was assessed by insulin resistance indices, lnHOMA-IR and
lnMatsuda, and AUC insulin during a 2-hour glucose tolerance test. Biochemical evidence of GR blockade was shown in all
individuals and across the group there was a significant reduction in insulin resistance: lnHOMA-IR (1.0vs0.6; p = 0.03),
lnHOMA-%beta (4.8vs4.3; p = 0.03) and lnMatsuda (1.2vs1.6; p = 0.03). Five out of six individuals showed a reduction in
insulin AUC .7237 pmol/l.min, and in two patients this showed a clinically significant cardiovascular benefit (as defined by
the Helsinki heart study).
Conclusions: Short-term GR antagonism is sufficient to reduce insulin resistance in some individuals with adrenal
incidentalomas and mild cortisol excess. Further assessment is required to assess if the responses may be used to stratify
therapy as adrenal incidentalomas may be a common remediable cause of increased cardiovascular risk
Studies on the Weak Itinerant Ferromagnet SrRuO3 under High Pressure to 34 GPa
The dependence of the Curie temperature Tc on nearly hydrostatic pressure has
been determined to 17.2 GPa for the weak itinerant ferromagnetic SrRuO3 in both
polycrystalline and single-crystalline form. Tc is found to decrease under
pressure from 162 K to 42.7 K at 17.2 GPa in nearly linear fashion at the rate
dTc/dP = -6.8 K/GPa. No superconductivity was found above 4 K in the pressure
range 17 to 34 GPa. Room-temperature X-ray diffraction studies to 25.3 GPa
reveal no structural phase transition but indicate that the average Ru-O-Ru
bond angle passes through a minimum near 15 GPa. The bulk modulus and its
pressure derivative were determined to be B =192(3) GPa and B' = 5.0(3),
respectively. Parallel ac susceptibility studies on polycrystalline CaRuO3 at 6
and 8 GPa pressure found no evidence for either ferromagnetism or
superconductivity above 4 K
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