Decoupling of Photon Propagator in Compact QED

In compact QED$_{2+1}$ quantum monopole fluctuations induce confinement by expelling electric flux in a dual Meissner effect. Guided by Landau-Ginzburg theory, one might guess that the inverse London penetration depth $\lambda^{-1}$---the only physical mass scale---equals the photon propagator mass pole $M_\gamma$. I show this is not true. Indeed, in the Villain approximation the monopole part of the partition function factorizes from the photon part, whose dynamical variables are Dirac strings. Since Dirac strings are gauge-variant structures, I conclude that $M_\gamma$ is physically irrelevant: it is not a blood relative of $\lambda$ or any other quantity in the gauge-invariant sector. This result is confirmed by numerical simulations in the full theory, where $M_\gamma$ is not sensitive to monopole prohibition but essentially vanishes if Dirac strings are prohibited.Comment: (Postscript file fixed; see file header.) 4 pages, DOE/ER/40617-135 and LSUHEP-10-9

Irrigation Efficiency of Santa Rosa Island Cloud Forest Restoration Project

Beginning in the 1800s, sheep and cattle ranching have caused significant erosion and devegetation of Santa Rosa Island, Channel Islands National Park. In an effort to contain what little soil is left and rebuild the native chaparral, the Cloud Forest Restoration Project is testing erosion control structures such as wattles, leaf litter fences and silt dams. This summer a drip irrigation system was installed along with fog capturing fences to supply water to native plants transplanted near the erosion control structures. As the project has grown, more irrigation has been added to increase the area available for transplanting. This irrigation system varies in elevation, slope, and diameter and lengths of irrigation lines. Because this project is experimentally monitored, it is important that all the transplants obtain the same amount of water. To check the efficiency of this system, the flow rates of 1.9L/hr rated pressure-compensating emitters along ¾” diameter polyethylene irrigation tubing were checked. Flow rates were relatively consistent at 1.53 L/hr, 1.60 L/hr and 1.59 L/hr for 1/3, 2/3 and the whole system turned on, respectively. Although one might expect the addition of more irrigation line and emitters to decrease water pressure and thus the flow rate of individual emitters, the flow rates of emitters were found to be unaffected, indicating the effectiveness of the pressure-compensation. However, the flow rates of emitters were consistently lower than their 1.9 L/hr rating. In conclusion, the irrigation system is currently providing equal water to each of the transplants, but at a rate lower than expected

Beyond averages: new approaches to understand heterogeneity and risk of technology success or failure in smallholder farming

Open Access ArticleIn recent years, many studies have demonstrated the heterogeneity of the smallholder production environment. Yet agronomic research for development (R4D) that aims to identify and test options for increasing productivity has not consistently adapted its approaches to such heterogeneous conditions. This paper describes the challenges facing research, highlighting the importance of variation in evaluating the performance of soil management recommendations, integrating aspects of production risk management within the formulation of recommendations, and proposing alternative approaches to implement agronomic R4D. Approaches are illustrated using two multi-locational on-farm paired trials, each having one no-input control treatment and a treatment with fertilizer application for maize in Western Kenya and for beans in Eastern Rwanda. The diversity of treatment responses should be embraced rather than avoided to gain a better understanding of current context and its relation with past management

S-matrix of N=2 Supersymmetric Sine-Gordon Theory

We investigate the S-matrix of N=2 supersymmetric sine-Gordon theory based on the N=2 supersymmetry and the quantum group structure. The topological charges play an important role to derive physical contents.Comment: 17 page

THE SALIENT CHARACTERISTICS OF MICROFINANCE INSTITUTIONS IN KENYA : (A Case Study of BIMAS)

The purpose of this study was to come up with a profile of the salient socio-economic characteristic of people who seek MFIs’ services. Specifically, the study was to shed light on their poverty status and their demographic characteristics. The research focused on clients of BIMAS operating within the five divisions of Embu district. The research findings gave a general profile of the clients reached by MFIs. The MFI clients are mainly male in the 26-40 age brackets that live in households of between 4 and 6 members which are predominantly male headed. A high proportion of the clients are married and do not suffer from any physical disability. Slightly over half of the clients have attained secondary school education and most have attended other training. In terms of their poverty status, over half of the clients have their children attending school. Majority can afford at least three ordinary meals per day and special meals thrice per week. The clients live in their own houses which have three or fewer rooms. The houses are largely made of brick walls, iron sheet roofs and concrete floors. The main source of energy for client household is firewood and charcoal and majority of them own a television. Key Words: Socio-economic characteristics, Demographic characteristics, Poverty statu

Properties of the Abelian Projection Fields in SU(N)SU(N) Lattice Gluodynamics

't~Hooft's abelian projection of $SU(N)$ gauge theory yields $N$ mutually constrained, compact abelian fields which are permutationally equivalent. We formulate the notion of ``species permutation'' symmetry of the $N$ abelian projection fields and discuss its consequences for cross-species correlators. We show that at large $N$ cross-species interactions are ${1\over N}$ suppressed relative to same-species interactions. Numerical simulations at $N=3$ support our symmetry arguments and reveal the existence of inter-species interactions of size {\cal O\/}\bigl({1\over N-1}\bigr) as analytically predicted.Comment: 13 pages, 1 postscript figure include