Biomagnetism and Ferritin Final Report

Methods for determining iron content in frog embryos and ferritin in rat intestine section

Geometry of all supersymmetric type I backgrounds

We find the geometry of all supersymmetric type I backgrounds by solving the gravitino and dilatino Killing spinor equations, using the spinorial geometry technique, in all cases. The solutions of the gravitino Killing spinor equation are characterized by their isotropy group in Spin(9,1), while the solutions of the dilatino Killing spinor equation are characterized by their isotropy group in the subgroup Sigma(P) of Spin(9,1) which preserves the space of parallel spinors P. Given a solution of the gravitino Killing spinor equation with L parallel spinors, L = 1,2,3,4,5,6,8, the dilatino Killing spinor equation allows for solutions with N supersymmetries for any 0 < N =< L. Moreover for L = 16, we confirm that N = 8,10,12,14,16. We find that in most cases the Bianchi identities and the field equations of type I backgrounds imply a further reduction of the holonomy of the supercovariant connection. In addition, we show that in some cases if the holonomy group of the supercovariant connection is precisely the isotropy group of the parallel spinors, then all parallel spinors are Killing and so there are no backgrounds with N < L supersymmetries.Comment: 73 pages. v2: minor changes, references adde

Adjusting to Skill Shortages: Complexity and Consequences

Skill shortages are often portrayed as a major problem for the economies of many countries including the Australian economy. Yet, there is surprisingly little evidence about their prevalence, causes and consequences. This paper attempts to improve our understanding about these issues by using econometric methods to analyse the Business Longitudinal Database, an Australian panel data-set with information about skill shortages in small- and medium-sized businesses during 2004/05. We use this information to: (1) explore the incidence of skill shortages and the business attributes that are associated with them; (2) identify which businesses face more complex skill shortages, as measured by the number of different causes reported simultaneously; and, uniquely, (3) examine how this complexity affects businesses' responses to skill shortages and aspects of their subsequent performance. We show that complex skill shortages are more likely than simpler (single-cause) skill shortages to persist and to trigger defensive responses from businesses. We reject the conception of skill shortages as a homogenous phenomenon, and demonstrate the importance of distinguishing between skill shortages according to whether they have simple or complex causes.skill shortages, small medium enterprises

Disability and Job Mismatches in the Australian Labour Market

We examine the relationship between disability, job mismatch, earnings and job satisfaction, using panel estimation on data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey (2001-2008). While we do not find any relationship between work-limiting disability and over-skilling, it appears that there is a positive relationship between work-limiting disability and over-education, which is consistent with disability onset leading to downward occupational movement, at least in relative terms. We find a negative correlation between work-limiting disability and both earnings and job satisfaction. However, there is only evidence of a causal relationship in terms of the latter, where the impact of disability is found to be multifaceted.job mismatch, disability, earnings, job satisfaction

On the Classification of All Self-Dual Additive Codes over GF(4) of Length up to 12

We consider additive codes over GF(4) that are self-dual with respect to the Hermitian trace inner product. Such codes have a well-known interpretation as quantum codes and correspond to isotropic systems. It has also been shown that these codes can be represented as graphs, and that two codes are equivalent if and only if the corresponding graphs are equivalent with respect to local complementation and graph isomorphism. We use these facts to classify all codes of length up to 12, where previously only all codes of length up to 9 were known. We also classify all extremal Type II codes of length 14. Finally, we find that the smallest Type I and Type II codes with trivial automorphism group have length 9 and 12, respectively.Comment: 18 pages, 4 figure

Job Mismatches and Labour Market Outcomes: Panel Evidence on Australian University Graduates

The interpretation of graduate mismatch manifested either as overeducation or as overskilling remains problematical. This paper uses annual panel information on both educational and skills mismatches uniquely found in the HILDA survey to analyse the relationship of both mismatches with pay, job satisfaction and job mobility. We find that overeducation and overskilling are distinct phenomena with different labour market outcomes and that their combination results in the most severe negative labour market outcomes. Using panel methodology reduces strongly the size of many relevant coefficients, questioning previous cross-section results and suggesting the presence of considerable unobserved heterogeneity which varies by gender.overeducation, overskilling, wages, satisfaction, mobility

Complete Weight Enumerators of Generalized Doubly-Even Self-Dual Codes

For any q which is a power of 2 we describe a finite subgroup of the group of invertible complex q by q matrices under which the complete weight enumerators of generalized doubly-even self-dual codes over the field with q elements are invariant. An explicit description of the invariant ring and some applications to extremality of such codes are obtained in the case q=4

Universal quantum computation with unlabeled qubits

We show that an n-th root of the Walsh-Hadamard transform (obtained from the Hadamard gate and a cyclic permutation of the qubits), together with two diagonal matrices, namely a local qubit-flip (for a fixed but arbitrary qubit) and a non-local phase-flip (for a fixed but arbitrary coefficient), can do universal quantum computation on n qubits. A quantum computation, making use of n qubits and based on these operations, is then a word of variable length, but whose letters are always taken from an alphabet of cardinality three. Therefore, in contrast with other universal sets, no choice of qubit lines is needed for the application of the operations described here. A quantum algorithm based on this set can be interpreted as a discrete diffusion of a quantum particle on a de Bruijn graph, corrected on-the-fly by auxiliary modifications of the phases associated to the arcs.Comment: 6 page

Exact enumeration of Hamiltonian circuits, walks, and chains in two and three dimensions

We present an algorithm for enumerating exactly the number of Hamiltonian chains on regular lattices in low dimensions. By definition, these are sets of k disjoint paths whose union visits each lattice vertex exactly once. The well-known Hamiltonian circuits and walks appear as the special cases k=0 and k=1 respectively. In two dimensions, we enumerate chains on L x L square lattices up to L=12, walks up to L=17, and circuits up to L=20. Some results for three dimensions are also given. Using our data we extract several quantities of physical interest