STRINGVACUA: A Mathematica Package for Studying Vacuum Configurations in String Phenomenology

We give a simple tutorial introduction to the Mathematica package STRINGVACUA, which is designed to find vacua of string-derived or inspired four-dimensional N=1 supergravities. The package uses powerful algebro-geometric methods, as implemented in the free computer algebra system Singular, but requires no knowledge of the mathematics upon which it is based. A series of easy-to-use Mathematica modules are provided which can be used both in string theory and in more general applications requiring fast polynomial computations. The use of these modules is illustrated throughout with simple examples.Comment: 21 pages, 9 figure

Changes in the labour force status of lone and couple Australian mothers, 1983-2002

Over the last twenty years there has been a substantial increase in the proportion of lone mothers employed part-time, while the proportion employed full-time is much the same in 2002 as it was in 1983. The experience of couple mothers is quite different, with both full-time and part-time employment increasing at similar rates. This paper uses data from the 1986 and 1996 Censuses to explore the possible reasons for the differences in the labour market trends of lone and couple mothers.

E-Learning for Teachers and Trainers : Innovative Practices, Skills and Competences

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Determinants of Australian mothers' employment: An analysis of lone and couple mothers

While the lower rates of employment of lone mothers as compared with couple mothers has been well documented, the reasons for the employment gap are less well understood. This paper uses data from the 1996 Australian Census to analyse the factors which explain the employment gap.

The economic consequences of divorce in six OECD countries

This report presents a cross-national comparison of the short- and medium-term economic effects of divorce. Overview This paper uses longitudinal data to estimate the short- and medium-term economic effects of divorce in the USA, the UK, Switzerland, Korea, Germany and Australia during the first decade of the 21st century. While the data, collected during the 2000s, were generally consistent with the findings from the existing literature, they reveal that the effects of divorce differ between the six countries included in this study

Transparency and Accountability in Bolivia: Does Voice Matter?

Using a survey of clients, doctors and nurses in thirty municipal hospitals, this study examines the scope and determinants of corruption in Bolivia`s public health sector. The authors find that `voice` mechanisms such as citizen activism and oversight are significant in exposing bribery and deterring the overpricing of medical supplies. The existence of `exit` options, such as recourse to private health service providers, additionally serves to deter corruption. Hierarchical controls, such as administrative regulations and procedures, seem to have little impact on hospital corruption, though further research is needed to verify this finding.

A Svarc-Milnor lemma for monoids acting by isometric embeddings

We continue our programme of extending key techniques from geometric group theory to semigroup theory, by studying monoids acting by isometric embeddings on spaces equipped with asymmetric, partially-defined distance functions. The canonical example of such an action is a cancellative monoid acting by translation on its Cayley graph. Our main result is an extension of the Svarc-Milnor Lemma to this setting.Comment: 11 page

A New Method for Finding Vacua in String Phenomenology

One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various non-perturbative effects. These include gaugino condensation and instantonic contributions to the superpotential.Comment: 27 pages, 5 .eps figures. V2: Minor corrections, reference adde

Silicon isotopic abundance toward evolved stars and its application for presolar grains

Galactic chemical evolution (GCE) is important for understanding the composition of the present-day interstellar medium (ISM) and of our solar system. In this paper, we aim to track the GCE by using the 29Si/30Si ratios in evolved stars and tentatively relate this to presolar grain composition. We used the APEX telescope to detect thermal SiO isotopologue emission toward four oxygen-rich M-type stars. Together with the data retrieved from the Herschel science archive and from the literature, we were able to obtain the 29Si/30Si ratios for a total of 15 evolved stars inferred from their optically thin 29SiO and 30SiO emission. These stars cover a range of masses and ages, and because they do not significantly alter 29Si/30Si during their lifetimes, they provide excellent probes of the ISM metallicity (or 29Si/30Si ratio) as a function of time. The 29Si/30Si ratios inferred from the thermal SiO emission tend to be lower toward low-mass oxygen-rich stars (e.g., down to about unity for W Hya), and close to an interstellar or solar value of 1.5 for the higher-mass carbon star IRC+10216 and two red supergiants. There is a tentative correlation between the 29Si/30Si ratios and the mass-loss rates of evolved stars, where we take the mass-loss rate as a proxy for the initial stellar mass or current stellar age. This is consistent with the different abundance ratios found in presolar grains. We found that older objects (up to possibly 10 Gyr old) in our sample trace a previous, lower 29Si/30Si value of about 1. Material with this isotopic ratio is present in two subclasses of presolar grains, providing independent evidence of the lower ratio. Therefore, the 29Si/30Si ratio derived from the SiO emission of evolved stars is a useful diagnostic tool for the study of the GCE and presolar grains.Comment: 7 pages, 4 figure