397 research outputs found
STUDY OF J/PSI THREE-BODY DECAYS INVOLVING BARYONS
The decay into a baryon pair and a pseudoscalar meson is computed,
for some channels, in lowest order in perturbative QCD, modeling the baryon
with a quark-diquark system. We use a set of parameters that has been proposed
by some authors in order to fit the proton magnetic form factor ,
the angular distribution of protons in the process and the width of .Comment: Plain Latex file, 10 pages; 1 figure appended as a uuencoded file;
Keywords : Charmonium, Baryons, Paiar production, Particle Structure
Glueball plus pion production in hadron collisions
Using a non--relativistic gluon bound--state model for glueballs (G), we
compute the subprocess , and we therefrom derive the
yield of the overall reaction , assuming the
glueball and the pion to be emitted with their transverse momenta large,
opposite and approximately equal. Numerical results are presented in the form
of spectra for various glueball candidates and their possible quantum
states, assuming those particles to be produced, in the type of reactions here
considered, at high--energy colliders such as the CERN Sp\=pS.Comment: 14 pages + 8 figures, REVTeX 3.0, figures appended as uuencoded,
compressed postscript file. To appear in Zeit. Phys.
St. Johns County v. Northeast Florida Builders Association and Florida School Impact Fees: An Exercise in Semantics
Leveling Up by Gamifying Freshman Engineering Clinic
This Work-In-Progress paper describes the development of a gamification platform for the Freshman Engineering Clinic II course at a North Eastern university and its proposed assessment strategy. Freshman Engineering Clinic II is a course designed to teach engineering students about multidisciplinary project design, with special focus on developing skills associated with teamwork, software application, and ethics. An important part of learning is receiving feedback as part of the learning cycle and studies have shown that increased feedback can be helpful in supporting student reflection and developing the intrinsic motivation necessary for mastering a task. One method of encouraging students to master material is by providing students with immediate feedback through gamification platforms. The gamification platform being employed in this implementation uses interactive learning techniques to provide students with clear cut goals as well as immediate feedback as an indicator of the student’s performance. Gamification transforms the traditional homework layout into an entirely new entity. Students can work to earn badges by completing assignments that interest them within the platform. Students also have the power to learn at their own pace and mechanics such as experience points, badges, leaderboards, and achievements can be used as motivating factors to encourage student completion of activities. In addition, the system acts as a scaffold for the students starting with activities that are easier and become progressively more challenging as their knowledge increases, while allowing them to repeat tasks as necessary to encourage mastery of course material. The effectiveness of this platform will be assessed by a combination of quantitative and qualitative measures. Student activity completion, accrual of badges and achievements, and the process through which students select the activities to pursue will all be monitored. Students will also complete the College and University Classroom Environment Inventory (CUCEI) to measure their perception of the classroom environment with the addition of the gamification platform. Qualitative feedback from students will be collected through open ended survey questions to gain a better appreciation for how the gamification platform impacted their course experience
Order-disorder transition in the Chialvo-Bak `minibrain' controlled by network geometry
We examine a simple biologically-motivated neural network, the three-layer version of the Chialvo-Bak `minibrain' [Neurosci. 90 (1999) 1137], and present numerical results which indicate that a non-equilibrium phase transition between ordered and disordered phases occurs subject to the tuning of a control parameter. Scale-free behaviour is observed at the critical point. Notably, the transition here is due solely to network geometry and not any noise factor. The phase of the network is thus a design parameter which can be tuned. The phases are determined by differing levels of interference between active paths in the network and the consequent accidental destruction of good paths
Altered brain energetics induces mitochondrial fission arrest in Alzheimer's Disease.
Altered brain metabolism is associated with progression of Alzheimer's Disease (AD). Mitochondria respond to bioenergetic changes by continuous fission and fusion. To account for three dimensional architecture of the brain tissue and organelles, we applied 3-dimensional electron microscopy (3D EM) reconstruction to visualize mitochondrial structure in the brain tissue from patients and mouse models of AD. We identified a previously unknown mitochondrial fission arrest phenotype that results in elongated interconnected organelles, "mitochondria-on-a-string" (MOAS). Our data suggest that MOAS formation may occur at the final stages of fission process and was not associated with altered translocation of activated dynamin related protein 1 (Drp1) to mitochondria but with reduced GTPase activity. Since MOAS formation was also observed in the brain tissue of wild-type mice in response to hypoxia or during chronological aging, fission arrest may represent fundamental compensatory adaptation to bioenergetic stress providing protection against mitophagy that may preserve residual mitochondrial function. The discovery of novel mitochondrial phenotype that occurs in the brain tissue in response to energetic stress accurately detected only using 3D EM reconstruction argues for a major role of mitochondrial dynamics in regulating neuronal survival
Survival of Human Neurofibroma in Immunodeficient Mice and Initial Results of Therapy With Pirfenidone
Neurofibromatosis type I is a common tumor predisposing disease in humans. Surgical therapy can be applied only in selected patients with resectable masses. Hence, development of new therapies for this disease is urgent. We used human neurofibroma implants in mice with severe combined immunodeficiency (SCID) as a model to test the toxicity and potential efficacy of pirfenidone, a new therapeutic agent. Two hundred twelve human neurofibromas were transplanted into various locations in 59 experimental animals, and 30 mice with implants received oral pirfenidone for up to six weeks. Survival of neurofibromas in animals treated with pirfenidone was lower than in the control group ([Formula: see text]). Tumors did not change histologic appearance or vascularization in response to pirfenidone. Treatment with pirfenidone, a new antifibrotic agent, inhibits survival of some tumors without causing toxicity in animals
Glueball production in radiative J/psi, Upsilon decays
Using a bound-state model of weakly bound gluons for glueballs made of two
gluons and a natural generalization of the perturbative QCD formalism for
exclusive hadronic processes, we present results for glueball production in
radiative J/psi, Upsilon decays into several possible glueball states,
including L \not= 0 ones. We perform a detailed phenomenological analysis,
presenting results for the more favored experimental candidates and for decay
angular distributions.Comment: RevTeX4, 26 pages, 11 eps figure
GeoChip-based Analysis of Groundwater Microbial Diversity in Norman Landfill
The Norman Landfill is a closed municipal solid waste landfill located on an alluvium associated with the Canadian River in Norman, Oklahoma. It has operated as a research site since 1994 because it is typical of many closed landfill sites across the U.S. Leachate from the unlined landfill forms a groundwater plume that extends downgradient approximately 250 m from the landfill toward the Canadian River. To investigate the impact of the landfill leachate on the diversity and functional structure of microbial communities, groundwater samples were taken from eight monitoring wells at a depth of 5m, and analyzed using a comprehensive functional gene array covering about 50,000 genes involved in key microbial processes, such as biogeochemical cycling of C, N, P, and S, and bioremediation of organic contaminants and metals. Wells are located within a transect along a presumed flow path with different distances to the center of the leachate plume. Our analyses showed that microbial communities were obviously impacted by the leachate-component from the landfill. The number of genes detected and microbial diversity indices in the center (LF2B) and its closest (MLS35) wells were significantly less than those detected in other more downgradient wells, while no significant changes were observed in the relative abundance (i.e., percentage of each gene category) for most gene categories. However, the microbial community composition or structure of the landfill groundwater did not clearly show a significant correlation with the distance from well LF2B. Burkholderia sp. and Pseudomonas sp. were found to be the dominant microbial populations detected in all wells, while Bradyrhizobium sp. and Ralstonia sp. were dominant populations for seven wells except LF2B. In addition, Mantel test and canonical correspondence analysis (CCA) indicate that pH, sulfate, ammonia nitrogen and dissolved organic carbon (DOC) have significant effects on the microbial community structure. The results suggest that the leachate from unlined landfills significantly impact the structures of groundwater microbial communities, and that more distal wells recover by natural attenuation
Wilson Loop Renormalization Group Flows
The locally BPS Wilson loop and the pure gauge Wilson loop map under AdS/CFT
duality to string world-sheet boundaries with standard and alternate
quantizations of the world-sheet fields. This implies an RG flow between the
two operators, which we verify at weak coupling. Many additional loop operators
exist at strong coupling, with a rich pattern of RG flows.Comment: 10 p, 2 figures. v3: Title change, expanded treatment of RG flow
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