Much ado about something: response to Haughton's reply to Duvendack and Palmer-Jones

PRIFPRI3; ISIDSG

High Noon for Microfinance Impact Evaluations: Re-investigating the Evidence from Bangladesh

Recently, microfinance has come under increasing criticism raising questions of the validity of iconic studies which have justified the microfinance phenomenon. This paper applies propensity score matching (PSM), which has become widely used for the analysis of observational data, to the study by Pitt and Khandker (1998) which has been labelled the most rigorous evidence supporting claims that microfinance benefits the poorest especially when targeted on women. After carefully reconstructing the data we differentiate outcomes by gender of borrower, take account of borrowing from several formal and informal sources, and find that the mainly positive impacts of microfinance that we observe are shown by sensitivity analysis to be highly vulnerable to selection on unobservables, and we are therefore not convinced that the relationships between microfinance and outcomes are causal.Microfinance; impact evaluation; Bangladesh; propensity score matching; sensitivity analysis

Retrospective Examination of Demand-side Energy-efficiency Policies

Energy efficiency policies are a primary avenue for reducing carbon emissions, with potential additional benefits from improved air quality and energy security. We review literature on a broad range of existing non-transportation energy efficiency policies covering appliance standards, financial incentives, information and voluntary programs, and government energy use (building and professional codes are not included). Estimates indicate these programs are likely to have collectively saved up to 4 quads of energy annually, with appliance standards and utility demand-side management likely making up at least half these savings. Energy Star, Climate Challenge, and 1605b voluntary emissions reductions may also contribute significantly to aggregate energy savings, but how much of these savings would have occurred absent these programs is less clear. Although even more uncertain, reductions in CO2, NOX, SO2, and PM-10 associated with energy savings may contribute about 10% more to the value of energy savings.energy efficiency policy, appliance standards, information, incentives, voluntary programs

Quantum chemical approach to atomic manipulation of chlorobenzene on the Si(111)-7×7 surface: Resonance localization, vibrational activation, and surface dynamics

We present a cluster model to describe the localization of hot charge carriers on the Si(111)-7×7 surface, which leads to (nonlocal) desorption of chlorobenzene molecules in scanning tunneling microscope (STM) manipulation experiments. The localized charge carriers are modeled by a small cluster. By means of quantum chemical calculations, this cluster model explains many experimental findings from STM manipulation. We show that the negative charge is mainly localized in the surface, while the positive one also resides on the molecule. Both resonances boost desorption: In the negative resonance the adatom is elevated; in the positive one the chemisorption bond between the silicon surface adatom and chlorobenzene is broken. We find normal modes promoting desorption matching experimental low-temperature activation energies for electron- and hole-induced desorption

Muon Dynamics in a Toroidal Sector Magnet

We present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoids)Comment: format aipproc.cls; aipproc.sty; 7 pages, two figures (*.ps). Submitted to the Proceedings of the 4th International Conference on Physics Potential and Development of mu-mu Colliders, San Francisco, Dec. 199

Energy Efficiency Economics and Policy

Energy efficiency and conservation are considered key means for reducing greenhouse gas emissions and achieving other energy policy goals, but associated market behavior and policy responses have engendered debates in the economic literature. We review economic concepts underlying consumer decisionmaking in energy efficiency and conservation and examine related empirical literature. In particular, we provide an economic perspective on the range of market barriers, market failures, and behavioral failures that have been cited in the energy efficiency context. We assess the extent to which these conditions provide a motivation for policy intervention in energy-using product markets, including an examination of the evidence on policy effectiveness and cost. While theory and empirical evidence suggest there is potential for welfare-enhancing energy efficiency policies, many open questions remain, particularly relating to the extent of some of the key market and behavioral failures.energy efficiency, appliance standards, energy policy, market failures, behavioral failures

Application of scanning probe energy loss spectroscopy to SERS-active metal nanostructures

Surface-enhanced Raman spectroscopy (SERS) relies on adsorbing target molecules onto metal nanostructures where the light can resonantly couple with localised surface plasmon resonances. These plasmons can be tuned by changing the nanostructure size, shape, spacing and composition, but this is a complex process. Therefore, having an experimental method that can directly map the plasmons would be extremely useful for developing SERS-active substrates. This paper investigates the possibility of applying a novel scanning probe method, scanning probe energy loss spectroscopy, to map the plasmonic behaviour of SERS-active metal nanostructures in order to optimise their enhancement factor and reproducibility

Interaction of nanoparticle properties and X-ray analytical techniques

In this work, Pt–Ti core–shell nanoparticles (NP) of 2 nm to 3 nm size and 30 000 u ± 1500 u as specified single particle mass, deposited on flat silicon substrates by means of a mass-selected cluster beam source, were used for the investigation of the modification of the X-ray Standing Wave (XSW) field intensity with increasing NP surface coverage. The focus of the investigation is on the determination of the range of validity of the undisturbed flat surface approach of the XSW intensity in dependence of the actual coverage rate of the surface. Therefore, the nanoparticles were characterized using reference-free grazing incidence X-ray fluorescence analysis (GIXRF) employing radiometrically calibrated instrumentation. In addition, near-edge X-ray absorption fine structure (NEXAFS) measurements were performed to investigate the binding state of titanium in the core–shell nanoparticles which was found to be amorphous TiO2. The combination of GIXRF measurements and of the calculated XSW field intensities allows for quantification of the core–shell nanoparticle surface coverage. For six different samples, the peak surface coverage could be determined to vary from 7% to 130% of a complete monolayer-equivalent coverage. A result of the current investigation is that core–shell nanoparticles modify the intensity distribution of the XSW field with increasing surface coverage. This experimental result is in line with calculated XSW field intensity distributions at different surface coverages using an effective density approach

Combining scanning tunneling microscope (STM) imaging and local manipulation to probe the high dose oxidation structure of the Si(111)-7×7 surface

Understanding the atomistic formation of oxide layers on semiconductors is important for thin film fabrication, scaling down conventional devices and for the integration of emerging research materials. Here, the initial oxidation of Si(111) is studied using the scanning tunneling microscope. Prior to the complete saturation of the silicon surface with oxygen, we are able to probe the atomic nature of the oxide layer formation. We establish the threshold for local manipulation of inserted oxygen sites to be +3.8 V. Only by combining imaging with local atomic manipulation are we able to determine whether inserted oxygen exists beneath surface-bonded oxygen sites and differentiate between sites that have one and more than one oxygen atom inserted beneath the surface. Prior to the creation of the thin oxide film we observe a flip in the manipulation rates of inserted oxygen sites consistent with more oxygen inserting beneath the silicon surface