Strength of weak ties in microfinance

Executive briefing paper No. 7, which is an additional project report as part of the 'Optimising the Dual Goals of Microfinance' research being funded by the Leverhulme Trust. The report summarises up-to-date findings arising from the PhD research

Strength of weak ties in microfinance

This research makes a contribution to knowledge by testing Granovetter’s (1973) theory of the strength of weak ties in microfinance based on an empirical study in India. Specifically, it looks to test if the addition of weak bridging ties to the networks of microfinance clients who own businesses will improve their businesses and help to reduce their poverty. This research also investigates Burt’s theories on structural holes (1992), brokerage and closure(2005) and network spillover (2010) can assist with the building of weak bridging ties. Microfinance is the delivery of financial services to the poor which includes credit, savings, insurance and remittances. The original goal of microfinance is to do financially sustainable poverty reduction. The key issue for microfinance is that it has not achieved levels of poverty reduction envisioned when the modern microfinance started. One reason for this is that microfinance clients start businesses with low barriers to entry which makes them very susceptible to competition. Also, the poor tend to inhabit fragmented social networks with few ties outside it that would bring needed information on markets, finance, suppliers, customers and the competition that would help to improve their businesses. Network analysis provides, with theory of the strength of weak ties, an approach that will give poor people access to information need by them to improve their businesses. India is one of the largest microfinance markets in the world which also has a unique form of microfinance. In addition to individual lending and joint liability groups, India has self-help groups which are essentially microbanks owned and operated by its members. Sari sellers, who happen to be members of self- help groups, are good example of a low barrier to entry business. Using a variation of the method developed by Kahn and Antonucci (1980), sari sellers were asked to identify the people they were connected to for supplies, finance, market information and customers. These are placed on a target diagram indicating how close these are to the sari seller who is at the centre of the target. Lines connecting the alters who know each other are drawn. In addition, a network intervention was conducted in attempt to introduce weak bridging ties into the social networks of the sari sellers. A simple method of providing sari sellers in the treatment group a list of other sari sellers they could contact for help while those in the control group did not receive the list. Several interesting findings came out of this research. Analysis of the sari sellers’ ego networks shows that there is a reliance on strong ties which confirms Granovetter’s (1983) argument. The analysis of the ego networks also show the sari sellers do have access to structural holes but do not take advantage of these. When the ego networks are combined using their contacts with the microfinance institution’s staff, analysis shows that the resulting network has a parent-subsidiary structure which reflects the hierarchical nature of Indian society. Finally, the analysis also shows that this network is fragmentary and fragile. Weak bridging ties would make the full network less fragile and allow the sari sellers to take advantage of the structural holes they find. This is what the intervention is attempting to do. While the intervention did not go as planned, evidence was found to support the hypothesis that addition of weak bridging ties to the social networks of sari sellers improved their businesses. A group of 15 disparate sari sellers created weak bridging ties to take advantage of one of the sari seller’s contacts to buy saris in bulk. Another sari seller saw a significant increase in sales for Diwali 2011 because a new member of her social network created a weak bridging tie which introduced her to many new customers

Collaborative models in BWDA and their self-help group in India

Collaborative relationships between stakeholders in the microfinance market and amongst members of Self-Help Groups (SHGs) in India are complex and reflect the potential for achieving financial sustainability and poverty reduction. As part of the Leverhulme-funded research project “Optimising the Dual Goals of Microfinance” this briefing paper presents preliminary results of field research undertaken in Tamul Nadu during July 2009.1 A major finding is the high level of dependence of the focal microfinance institution on a public funding organisation in the region and the degree of involvement by group leaders in the SHGs

Comparisons of halogenated ß-nitrostyrenes as antimicrobial agents

The influence of three types of halogen-substituted E-ß-methyl-ß-nitrostyrenes (such as Compounds B, D, H) to overcome bacterial activity that is currently a significant health threat was studied. The evaluations of their bio-potency was measured and related to their structure and activity relationships for the purposes of serving to inhibit and overcoming resistant microorganisms. In particular, fluorine-containing ß-nitrostyrenes were found to be highly active antimicrobial agents. The addition of the ß-bromo group enhanced the antibacterial activity significantly. Our work has illustrated that halogen substituents at both the 4-position in the aromatic ring and also at the ß-position on the alkene side chain of nitropropenyl arenes enhanced the antimicrobial activity of these compounds

Ground state solution of Bose-Einstein condensate by directly minimizing the energy functional

In this paper, we propose a new numerical method to compute the ground state solution of trapped interacting Bose-Einstein condensation (BEC) at zero or very low temperature by directly minimizing the energy functional via finite element approximation. As preparatory steps we begin with the 3d Gross-Pitaevskii equation (GPE), scale it to get a three-parameter model and show how to reduce it to 2d and 1d GPEs. The ground state solution is formulated by minimizing the energy functional under a constraint, which is discretized by the finite element method. The finite element approximation for 1d, 2d with radial symmetry and 3d with spherical symmetry and cylindrical symmetry are presented in detail and approximate ground state solutions, which are used as initial guess in our practical numerical computation of the minimization problem, of the GPE in two extreme regimes: very weak interactions and strong repulsive interactions are provided. Numerical results in 1d, 2d with radial symmetry and 3d with spherical symmetry and cylindrical symmetry for atoms ranging up to millions in the condensation are reported to demonstrate the novel numerical method. Furthermore, comparisons between the ground state solutions and their Thomas-Fermi approximations are also reported. Extension of the numerical method to compute the excited states of GPE is also presented.Comment: 33 pages, 22 figure

Combined collider constraints on neutralinos and charginos

Searches for supersymmetric electroweakinos have entered a crucial phase, as the integrated luminosity of the Large Hadron Collider is now high enough to compensate for their weak production cross-sections. Working in a framework where the neutralinos and charginos are the only light sparticles in the Minimal Supersymmetric Standard Model, we use gambit to perform a detailed likelihood analysis of the electroweakino sector. We focus on the impacts of recent ATLAS and CMS searches with 36 fb$^{-1}$ of 13 TeV proton-proton collision data. We also include constraints from LEP and invisible decays of the $Z$ and Higgs bosons. Under the background-only hypothesis, we show that current LHC searches do not robustly exclude any range of neutralino or chargino masses. However, a pattern of excesses in several LHC analyses points towards a possible signal, with neutralino masses of $(m_{\tilde{\chi}_1^0}, m_{\tilde{\chi}_2^0}, m_{\tilde{\chi}_3^0}, m_{\tilde{\chi}_4^0})$ = (8-155, 103-260, 130-473, 219-502) GeV and chargino masses of $(m_{\tilde{\chi}_1^{\pm}}, m_{\tilde{\chi}_2^{\pm}})$ = (104-259, 224-507) GeV at the 95% confidence level. The lightest neutralino is mostly bino, with a possible modest Higgsino or wino component. We find that this excess has a combined local significance of $3.3\sigma$, subject to a number of cautions. If one includes LHC searches for charginos and neutralinos conducted with 8 TeV proton-proton collision data, the local significance is lowered to 2.9$\sigma$. We briefly consider the implications for dark matter, finding that the correct relic density can be obtained through the Higgs-funnel and $Z$-funnel mechanisms, even assuming that all other sparticles are decoupled. All samples, gambit input files and best-fit models from this study are available on Zenodo.Comment: 38 pages, 16 figures, v3 is the version accepted by EPJ

Adaptable-radius, time-orbiting magnetic ring trap for Bose-Einstein condensates

We theoretically investigate an adjustable-radius magnetic storage ring for laser-cooled and Bose-condensed atoms. Additionally, we discuss a novel time-dependent variant of this and other ring traps. Time-orbiting ring traps provide a high optical access method for spin-flip loss prevention near a storage ring's circular magnetic field zero. Our scalable storage ring will allow one to probe the fundamental limits of condensate Sagnac interferometry.Comment: 5 pages, 3 figures. accepted in J Phys

Watching dark solitons decay into vortex rings in a Bose-Einstein condensate

We have created spatial dark solitons in two-component Bose-Einstein condensates in which the soliton exists in one of the condensate components and the soliton nodal plane is filled with the second component. The filled solitons are stable for hundreds of milliseconds. The filling can be selectively removed, making the soliton more susceptible to dynamical instabilities. For a condensate in a spherically symmetric potential, these instabilities cause the dark soliton to decay into stable vortex rings. We have imaged the resulting vortex rings.Comment: 4 pages, 4 figure

Dynamics of trapped bright solitons in the presence of localized inhomogeneities

We examine the dynamics of a bright solitary wave in the presence of a repulsive or attractive localized ``impurity'' in Bose-Einstein condensates (BECs). We study the generation and stability of a pair of steady states in the vicinity of the impurity as the impurity strength is varied. These two new steady states, one stable and one unstable, disappear through a saddle-node bifurcation as the strength of the impurity is decreased. The dynamics of the soliton is also examined in all the cases (including cases where the soliton is offset from one of the relevant fixed points). The numerical results are corroborated by theoretical calculations which are in very good agreement with the numerical findings.Comment: 8 pages, 5 composite figures with low res (for high res pics please go to http://www.rohan.sdsu.edu/~rcarrete/ [Publications] [Publication#41