Social relations and remittances: Evidence from Canadian micro data

This paper models transfers outside the household for both the Canadian- born and foreign-born Canadian populations in a traditional expenditure framework with an unique composition of goods to illustrate the special motivations to remit by immigrants. We theorise that remittances to persons outside the households represent transfers to maintain social relations with relatives and friends and religious/charitable remittances are expenditures which foster group membership. Using Canadian survey data we estimate transfer functions as part of a larger expenditure system and calculate Engel elasticities for remittances to persons and to charities by both the Canadian and foreign-born populations. We conclude that expenditures to enhance social relations with relatives and friends (i.e. remittances to persons) are a normal good for recent Asian immigrants and a luxury good for all other immigrants and Canadians. Moreover, Asian households are the only ones that remit significantly more of their total expenditures to persons upon arrival, compared to the Canadian reference group, and their remittance behaviour does not converse to that of Canadian-born over time. This latter fact indicates strong cultural differences within the remitting households, most probably due to the fact that Asian households have stronger social ties to their extended family. Finally, with the exception of lower income North American and European immigrant households, all other immigrant groups and Canadians generally consider group membership contributions (i.e. charitable remittances) as a greater necessity than inter-household transfers. --international migration,household behaviour,remittances

Endogenous Entry, Product Variety, and Business Cycles

This paper builds a framework for the analysis of macroeconomic fluctuations that incorporates the endogenous determination of the number of producers over the business cycle. Economic expansions induce higher entry rates by prospective entrants subject to irreversible investment costs. The sluggish response of the number of producers (due to the sunk entry costs) generates a new and potentially important endogenous propagation mechanism for real business cycle models. The stock-market price of investment (corresponding to the creation of new productive units) determines household saving decisions, producer entry, and the allocation of labor across sectors. The model performs at least as well as the benchmark real business cycle model with respect to the implied second-moment properties of key macroeconomic aggregates. In addition, our framework jointly predicts a procyclical number of producers and procyclical profits even for preference specifications that imply countercyclical markups. When we include physical capital, the model can reproduce the variance and autocorrelation of GDP found in the data.

What accounts for the changes in U.S. fiscal policy transmission?

Using vector autoregressions on U.S. time series for 1957-1979 and 1983-2004, we find government spending shocks to have stronger effects on output, consumption, and wages in the earlier sample. We try to account for this observation within a DSGE model featuring price rigidities and limited asset market participation. Specifically, we estimate the structural parameters of the model for both samples by matching impulse responses. Model-based counterfactual experiments suggest that increased asset market participation accounts for some of the changes in fiscal transmission. However, the key quantitative factor appears to be the more active monetary policy of the Volcker-Greenspan period. JEL Classification: E21, E62, E63Asset Market Participation, DSGE, Fiscal Policy, government spending, Minimum Distance Estimation, monetary policy, Vector autoregression

Supersymmetric Canonical Commutation Relations

We present unitarily represented supersymmetric canonical commutation relations which are subsequently used to canonically quantize massive and massless chiral,antichiral and vector fields. The massless fields, especially the vector one, show new facets which do not appear in the non superymmetric case. Our tool is the supersymmetric positivity induced by the Hilbert-Krein structure of the superspace.Comment: 14 page

Van der Waerden calculus with commuting spinor variables and the Hilbert-Krein structure of the superspace

Working with anticommuting Weyl(or Mayorana) spinors in the framework of the van der Waerden calculus is standard in supersymmetry. The natural frame for rigorous supersymmetric quantum field theory makes use of operator-valued superdistributions defined on supersymmetric test functions. In turn this makes necessary a van der Waerden calculus in which the Grassmann variables anticommute but the fermionic components are commutative instead of being anticommutative. We work out such a calculus in view of applications to the rigorous conceptual problems of the N=1 supersymmetric quantum field theory.Comment: 14 page

The Minimum Spanning Tree Constant in Geometrical Probability and Under the Independent Model; A Unified Approach

Given n uniformly and independently points in the d dimensional cube of unit volume, it is well established that the length of the minimum spanning tree on these n points is asymptotic to /3MsT(d)n(d-l)/d,where the constant PMST(d) depends only on the dimension d. It has been a major open problem to determine the constant 3MST(d). In this paper we obtain an exact expression of the constant MST(d) as a series expansion. Truncating the expansion after a finite number of terms yields a sequence of lower bounds; the first 3 terms give a lower bound which is already very close to the empirically estimated value of the constant. Our proof technique unifies the derivation for the MST asymptotic behavior for the Euclidean and the independent model

Microtubule dynamics depart from wormlike chain model

Thermal shape fluctuations of grafted microtubules were studied using high resolution particle tracking of attached fluorescent beads. First mode relaxation times were extracted from the mean square displacement in the transverse coordinate. For microtubules shorter than 10 um, the relaxation times were found to follow an L^2 dependence instead of L^4 as expected from the standard wormlike chain model. This length dependence is shown to result from a complex length dependence of the bending stiffness which can be understood as a result of the molecular architecture of microtubules. For microtubules shorter than 5 um, high drag coefficients indicate contributions from internal friction to the fluctuation dynamics.Comment: 4 pages, 4 figures. Updated content, added reference, corrected typo