International Migration, Income Taxes and Transfers: A Welfare Analysis

An important issue in public policy debates is the effect of international migration on welfare in source and host countries. We address this issue by constructing a general equilibrium model of a two-class source or host country. Each country produces many traded and non-traded goods, uses income taxes and distributes the tax receipts equally to all individuals. The analysis examines the effects of permanent migration on class, and national welfare. We show, among other things, that marginal immigration hurts people already in the country regardless of whether or not non-traded goods exist. The presence of international capital mobility, however, may reverse the above result.international migration, taxes, transfers, welfare

Catalogue of candidate emission-line objects in the Small Magellanic Cloud

H\alpha and [O III] narrow band, wide field (7 * 7 degree), CCD images of the Small Magellanic Cloud were compared and a catalogue of candidate planetary nebulae and H\alpha emission-line stars was compiled. The catalogue contains 131 planetary nebulae candidates, 23 of which are already known to be or are probable planetary nebulae or very low excitation objects. Also, 218 emission-line candidates have been identified with 113 already known. Our catalogue therefore provides a useful supplement to those of Meyssonnier & Azzopardi (1993) and Sanduleak, MacConnell & Davis Phillip (1978). Further observations are required to confirm the identity of the unknown objects.Comment: 8 pages, accepted by MNRA

Modulation of Negative Work Output from a Steering Muscle of the Blowfly Calliphora Vicina

Of the 17 muscles responsible for flight control in flies, only the first basalar muscle (b1) is known to fire an action potential each and every wing beat at a precise phase of the wing-beat period. The phase of action potentials in the b1 is shifted during turns, implicating the b1 in the control of aerodynamic yaw torque. We used the work loop technique to quantify the effects of phase modulation on the mechanical output of the b1 of the blowfly Calliphora vicina. During cyclic length oscillations at 10 and 50 Hz, the magnitude of positive work output by the b1 was similar to that measured previously from other insect muscles. However, when tested at wing-beat frequency (150 Hz), the net work performed in each cycle was negative. The twitch kinetics of the b1 suggest that negative work output reflects intrinsic specializations of the b1 muscle. Our results suggest that, in addition to a possible role as a passive elastic element, the phase-sensitivity of its mechanical properties may endow the b1 with the capacity to modulate wing-beat kinematics during turning maneuvers

The Meaning of Eros/Macho

Most of the mass density in the Universe---and in the halo of our own galaxy---exists in the form of dark matter. Overall, the contribution of luminous matter (in stars) to the mass density of the Universe is less than 1\%; primordial nucleosynthesis indicates that baryons contribute between 1\% and 10\% of the critical density (0.01h^{-2}\la \Omega_B\la 0.02h^{-2}; $h=$ the Hubble constant in units of 100\kms\Mpc^{-1}); and other evidence indicates that the total mass density is at least 10\% of critical density, and likely much greater. If the universal density is as low as 10\% of the critical density there may be but one kind of dark matter. More likely, the universal density is greater than 10\%, and there are two kinds of dark matter, and thus two dark matter problems: In what form does the baryonic dark matter exist? and In what form does the nonbaryonic dark matter exist? The MACHO and EROS collaborations have presented evidence for the microlensing of stars in the LMC by $10^{-1\pm 1}M_\odot$ dark objects in the halo of our own galaxy and may well have solved {\it one} of the dark matter puzzles by identifying the form of the baryonic dark matter.Comment: 15 pages Latex + 3 Figs available on request, FNAL---Pub-93/298-

Graph Saturation in Multipartite Graphs

Let $G$ be a fixed graph and let ${\mathcal F}$ be a family of graphs. A subgraph $J$ of $G$ is ${\mathcal F}$-saturated if no member of ${\mathcal F}$ is a subgraph of $J$, but for any edge $e$ in $E(G)-E(J)$, some element of ${\mathcal F}$ is a subgraph of $J+e$. We let $\text{ex}({\mathcal F},G)$ and $\text{sat}({\mathcal F},G)$ denote the maximum and minimum size of an ${\mathcal F}$-saturated subgraph of $G$, respectively. If no element of ${\mathcal F}$ is a subgraph of $G$, then $\text{sat}({\mathcal F},G) = \text{ex}({\mathcal F}, G) = |E(G)|$. In this paper, for $k\ge 3$ and $n\ge 100$ we determine $\text{sat}(K_3,K_k^n)$, where $K_k^n$ is the complete balanced $k$-partite graph with partite sets of size $n$. We also give several families of constructions of $K_t$-saturated subgraphs of $K_k^n$ for $t\ge 4$. Our results and constructions provide an informative contrast to recent results on the edge-density version of $\text{ex}(K_t,K_k^n)$ from [A. Bondy, J. Shen, S. Thomass\'e, and C. Thomassen, Density conditions for triangles in multipartite graphs, Combinatorica 26 (2006), 121--131] and [F. Pfender, Complete subgraphs in multipartite graphs, Combinatorica 32 (2012), no. 4, 483--495].Comment: 16 pages, 4 figure

Barker Central School District and Barker Central School Support Staff

In the matter of the fact-finding between the Barker Central School District, employer, and the Barker Central School Support Staff, union. PERB case no. M2009-035