A Comparison of Two Methods of College Instruction

The literature on the subject of college methods of instruction is replete with theoretic discussions and treatments. Studies devoted to scientific appraisal of specific methods, however, are few in number. The constant demand for efficiency in dealing with the rapidly increasing college enrollment necessitates scientific measurement of the effectiveness of particular methods

Capture of Neon Atoms by \u3csup\u3e4\u3c/sup\u3eHe Clusters

Neon atoms are captured by helium clusters in a crossed-beam experiment. The capture process depends strongly on the cluster beam source conditions. We identify a sharply defined region corresponding to expansions passing near the critical point for which the capture probability is anomalously large

Promene EKG tokom hiperinfuzione terapije konja sa hroničnim opstruktivnim oboljenjima

This study describes investigations into the electrocardiogram changes in 27 horses with chronic obstructive pulmonary disease (COPD), during hyperinfusion therapy with isotonic saline solution. Immediately after hyperinfusion therapy the equine ECG showed a temporary sinus tachycardia without atrial and ventricular rhythm disturbances. After infusion a highly significant shortening of the PQ-, QT and TP-intervals was observed. There was a positive correlation between the RR-interval and the duration of the PQ- and QT-intervals, but not with the duration of the P-, QRS- and T-waves.Ova studija opisuje ispitivanja promena u elektrokardiogramu 27 konja sa hroničnim plućnim oboljenjima (COPD) utoku hiperinfuzione terapije izotoničnim rastvorom soli. Neposredno posle hiperinfuzione terapije, EKG konja je pokazivao postojanje povremene sinusne tahikardije bez poremećaja ritma rada pretkomora i komora. Posle infuzije zapaženo je veoma izraženo skraćenje PQ, QT, TP intervala. Izražena je povezanost između RR intervala i trajanja PQ i QT intervala, ali ne i sa pojavom P, QRS i T talasa

Methicillin-resistant Staphylococcus aureus from infections in horses in Germany are frequent colonizers of veterinarians but rare among MRSA from infections in humans

AbstractA total of 272 methicillin-resistant Staphylococcus aureus (MRSA) from equine infections originating from 17 equine hospitals and 39 veterinary practices in Germany as well as 67 isolates from personnel working at equine clinics were subjected to molecular typing. The majority of isolates from horses was attributed to clonal complex (CC) 398 (82.7%). Within CC398, 66% of isolates belonged to a subpopulation (clade) of CC398, which is associated with equine clinics.MRSA attributed to CC8 (ST254, t009, t036, SCCmecIV; ST8, t064, SCCmecIV) were less frequent (16.5%). Single isolates were attributed to ST1, CC22, ST130, and ST1660. The emergence of MRSA CC22 and ST130 in horses was not reported so far. Nasal MRSA colonization was found in 19.5% of veterinary personnel with occupational exposure to horses. The typing characteristics of these isolates corresponded to isolates from equine infections.Comparing typing characteristics of equine isolates with those of a substantial number of isolates from human infections typed at the German Reference Center for Staphylococci and Enterococci (2006–2014; n=10864) yielded that the proportion of isolates exhibiting characteristics of MRSA from equine medicine is very low (<0.5%). As this low proportion was also found among MRSA originating from nasal screenings of human carriers not suffering from a staphylococcal infection (n=5546) transmission of MRSA from equine clinics to the community seems to be rare so far

Variational Calculations for 3^3He Impurities on 4^4He Droplets

Variational Monte Carlo method is used to calculate ground state properties of $^4$He droplets, containing 70, 112, 168, 240, 330, and 728 particles. The resulting particle and kinetic energy densities are used as an input in the Feynman-Lekner theory for $^3$He impurities. The kinetic energy density of $^4$He atoms and the energy of the $^3$He surface states are compared with the results of previous phenomenological calculations.Comment: 12 pages, in revtex 3.0, with 5 .ps figure

Discovery of the Cadmium Isotopes

Thirty-seven cadmium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.Comment: to be published in Atomic Data and Nuclear Data Table

Numerical and Experimental Investigations of Polyurethane Foam for Use as Cask Impact Limiter in Accidental Drop Scenarios -12099

ABSTRACT Rigid, closed-cell polyurethane foams are frequently used as cask impact limiters in nuclear materials and hazardous waste transport due to their high energy-absorption potential. When assessing the cask integrity in accidental scenarios based on numerical simulations, a description of the foam damping properties is required for different strain rates and for a wide temperature range with respect to waste heat generation in conjunction with critical operating and environmental conditions. Implementation and adaption of a respective finite element material model strongly relies on an appropriate experimental data base. Even though extensive impact experiments were conducted e.g. in Sandia National Laboratories [1], Savannah River National Laboratory Hence, BAM who is in charge of the mechanical evaluation of such packages within the approval procedure in Germany, incorporated systematic test series into a comprehensive research project aimed to develop numerical methods for a couple of damping materials. In a first step, displacement driven compression tests have been performed on confined, cubic specimens at five loading rates ranging from 0.02 mm/s to 3 m/s at temperatures between +90°C and -40°C. Materials include two different polyurethane foam types called FR3718 and FR3730 having densities of 280 kg/m³ and 488 kg/m³ from the product line-up of General Plastics Manufacturing Company Currently, the selected numerical material input values are validated and optimized by means of more complex loading configurations with the prospect of establishing methods applicable to impact limiters under severe accidental conditions. The reference data base is provided by experiments, where weights between 212 kg and 1200 kg have been dropped from heights between 1.25 m and 7 m on confined 10 cm cubic foam specimens. By presenting the deviations between experimental values and the corresponding output of finite element simulations, the potentials and restrictions of the resulting models are highlighted

Simulation of the space debris environment in LEO using an analytical approach

Several numerical approaches exist to simulate the evolution of the space debris environment. These simulations usually rely on the propagation of a complete population of objects in order to determine the collision probability for each object. Using a Monte Carlo (MC) approach the chances for events, such as explosions and collisions, are triggered based on an assumed probability distribution. So in many different scenarios different objects are fragmented and contribute to a different version of the space debris environment. Finally, the results of the different scenarios are averaged to get a statistically significant estimation. This method is computationaly very expensive due to the propagation of the objects and the application of the MC method. At the Institute of Aerospace Systems (ILR) an analytical model capable of describing the evolution of the space debris environment has been developed and implemented. The model is based on source and sink mechanisms, where yearly launches as well as collisions and explosions are considered as sources. The natural decay and post mission disposal measures are the only sink mechanisms. This method reduces the computational costs tremendously. In order to achieve this benefit a few simplifications have been applied. The approach of the model partitions the LEO into altitude shells. Only two kinds of objects are considered, intact bodies and fragments, which are also divided into diameter bins. As an extension to the previously presented model the eccentricity has additionally been taken into account with 67 eccentricity bins. While a set of differential equations has been implemented in a generic manner, the Euler method has been chosen to integrate the equations for a given time span. For this paper parameters have been chosen so that the model is able to reflect the results of the numerical MC-based simulation LUCA, which is also being developed at the ILR. The evolution of the population in LEO for a 200 years time span is shown and compared for both approaches using step sizes of 1 year. For selected objects in LEO the flux and environmental criticality values are shown. In conclusion the field of application for such a fast analytical model is shown

Entrance Channel X-HF (X=Cl, Br, and I) Complexes studied by High-Resolution Infrared Laser Spectroscopy in Helium Nanodroplets

Rotationally resolved infrared spectra are reported for halogen atom - HF free radical complexes formed in helium nanodroplets. An effusive pyrolysis source is used to dope helium droplets with Cl, Br and I atoms, formed by thermal dissociation of Cl$_2$, Br$_2$ and I$_2$. A single hydrogen fluoride molecule is then added to the droplets, resulting in the formation of the X-HF complexes of interest. Analysis of the resulting spectra confirms that the observed species have $^2\Pi_{3/2}$ ground electronic states, consistent with the linear hydrogen bound structures predicted from theory. Stark spectra are also reported for these species, from which the permanent electric dipole moments are determined.Comment: 41 pages, 16 figures, 5 table