Constructing social division to support cooperation : theory and evidence from Nepal

Many societies are divided into multiple smaller groups. The defining feature of these groups is that certain kinds of interaction are more likely to take place within a group than across groups. I build a model in which group divisions are enforced through a reputational penalty for interacting with members of different groups. Agents who interact with members of different groups find that they can support lower levels of cooperation in the future. The model explains why agents may be punished by the other members of their group for interacting with members of different groups and why agents are punished for interacting with members of some groups but not others. I test the empirical implication that there should be less cooperation among members of groups that make up a larger percentage of their communities. I discuss the origin and possible future of social division

PLASMON EFFECTS IN SOLID-STATE RADIATION DETECTORS

We have examined the role of plasmons on the electron energy response of solid-state (Si and Ge) radiation detectors. We found that at the level of parts per thousand, internal-conversion electron calibration techniques do not suffice to yield an adequate response function. In particular, spectral distortions in the detection of low-energy beta-particles have been found which are not accounted for by the usual calibration methods. Thus, a small but significant error can arise from energy loss to low-energy plasmons in Si and Ge detectors. The proximity of the plasmon energy to the end-point singularity and the quadratic form of the beta-decay spectrum may account for the effect interpreted as a 17 keV neutrino. Similar errors can also arise in other subtle solid-state measurements as, for example, in the X-ray edge absorption and emission spectra of metals and semiconductors

Monetary policy operating procedures: the Peruvian case

Both the objective and the powers of the central bank are clearly specified in its legal framework. In this respect, its aims and activities are transparent and explicit. Monetary policy influences the monetary aggregates through market instruments, sending clear signals to economic agents regarding the direction and objectives pursued. Despite major changes in monetary policy management, policy implementation still encounters problems. The main problems are: • A modest quantity of money: total liquidity (including deposits in local and foreign currency), i.e. the quantity of money in circulation in the economy, is equal to just over 180/0 of GDP with a high degree of dollarisation (almost 75 0/0 of total deposits is in foreign currency). The persistently low level of local currency means that seasonal liquidity flows, generated for example by tax payments, can become quite large in relative terms. • The central bank’s capacity to buy foreign exchange is restricted by the cost of sterilisation. This may induce a rise in interest rates, in turn attracting larger foreign capital inflows and leading to an appreciation of the exchange rate. • The dealing room’s intervention strategy has improved; however, it is still restricted to buy dollars, while maintaining a passive stance when the market requires a larger dollar supply. • Financial market segmentation: the financial market is made up of groups of institutions of widely different size and performance. Interinstitutional behaviour is therefore not homogeneous. Market segmentation creates situations in which the system as a whole can show a liquidity surplus, while on an individual basis some banks are encountering liquidity problems. Institutions with liquidity problems do not have access to interbank loans, owing either to the market’s inefficiency or to the institution’s specific situation. This creates a need for collateralised credits, bringing about an increase in the monetary base, despite the excess reserves in the system as a whole. As these entities’ demand for central bank CDs is usually small, the scope for repurchase operations as a source of funds is limited.monetary policy instruments