Fifty Years of Candidate Pulsar Selection - What next?

For fifty years astronomers have been searching for pulsar signals in observational data. Throughout this time the process of choosing detections worthy of investigation, so called candidate selection, has been effective, yielding thousands of pulsar discoveries. Yet in recent years technological advances have permitted the proliferation of pulsar-like candidates, straining our candidate selection capabilities, and ultimately reducing selection accuracy. To overcome such problems, we now apply intelligent machine learning tools. Whilst these have achieved success, candidate volumes continue to increase, and our methods have to evolve to keep pace with the change. This talk considers how to meet this challenge as a community.Comment: 4 pages, submitted: Proceedings of Pulsar Astrophysics: The Next Fifty Years, IAU Symposium 33

The meaning of the MASA apology

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What Advertisers Want: Measuring Institutions: Indicators of Political Rights, Property Rights and Political Instability in Malawi

In the 2008 Budget Review, the South African government announced its intention to levy a 2c/kWh tax on the sale of electricity generated from non-renewable sources. This measure is intended to serve a dual purpose of helping to manage the current electricity supply shortages and to protect the environment (National Treasury 2008). An electricity generation tax is set to have an impact on the South African economy. However, several instruments have been proposed in the literature to protect the competitiveness and economy of a country when it imposes a green tax, one of these remedies being border tax adjustments.This paper evaluates the effectiveness for the South African case, of border tax adjustments (BTAs) in counteracting the negative impact of an electricity generation tax on competitiveness. The remedial effects of the BTAs are assessed in the light of their ability to maintain the environmental benefits of the electricity generation tax. Additionally, the the Global Trade Analysis Project (GTAP) model is used to evaluate the impact of an electricity generation tax on the South African, SACU and SADC economies and to explore the possibility of reducing the economic impact of the electricity generation tax through BTAs. The results show that an electricity generation tax will lead to a contraction in South African gross domestic product (GDP). Traditional BTAs are unable to address these negative impacts. We propose a reversedBTA approach where gains from trade are utilised to counteract the negative effects of an electricity generation tax, while retaining the environmental benefits associated with the electricity generation tax. This is achieved through a lowering of import tariffs, as this will reduce production costs and thereby restore the competitiveness of the South African economy. The reduction in import tariffs not only negates the negative GDP impact of the electricity generation tax, but the bulk of CO2 abatement from the electricity generation tax is retained.

Persistence and Yield of Ten Lucerne Cultivars Under Dryland and Heavy Continuous Grazing in the Western Cape Province of South Africa

Pastures in the Rûens region of the Western Cape are mainly legume based with lucerne being the most important and productive legume used (van Heerden & Tainton, 1987). Most pastures are sown to the land race cultivar SA Standard (SAS). Grazing resistance of SAS is high, but relative to other imported cultivars resistance to endemic insect and other pests is poor. This study therefore involves the evaluation for yield and persistence of nine new cultivars compared to SAS under local grazing conditions

Health surveillance of employees on a lead mine, 1979-1989

Health surveillance of employees at a lead mine in the northern Cape, employing about 1 400 people, is specifically aimed at early detection of excessive lead absorption, which is the main chemical hazard. Over a period of 9 years the blood lead level distribution showed very few values (2,5%) that exceeded 60 μg/100 ml.Health surveillance of employees at a lead mine in the northern Cape, employing about 1 400 people, is specifically aimed at early detection of excessive lead absorption, which is the main chemical hazard. Over a period of 9 years the blood lead level distribution showed very few values (2,5%) that exceeded 60 μg/100 ml

Optimering van tydreeks-analise-metodes vir veranderlike astrofisiese bronne: AE Aquarii

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Management of premature rupture of the membranes after 34 weeks' gestation - early versus delayed induction of labour

Objective. To determine the optimal way to manage patients with premature rupture of the membranes after 34 weeks' gestation.Design. A prospective, randomised controlled trial comparing immediate induction and delayed induction after 24 • 48 hours.Setting. Tygerberg Hospital, Gape Town.Participants. Seventy consecutive patients with premature rupture of the membranes who presented at Tygert&gt;erg Hospital between July and October 1991.Main outcome measures. The two groups were compared with regard to infectious morbidity and antibiotic requirements in the mothers and babies, days spent in hospital, caesarean section rates, duration of labour and analgesic requirements.Results. There was no difference between the two groups in terms of infectious morbidity in either the mothers or the babies, the duration of labour or the caesarean section rates. Nine patients (26%) in the delayed induction group required analgesic treatment during labour versus 18 patients (52%) in the group that was induced immediately (P = 0.049; odds ratio = 0.327; 95% confidence limits = 0.014 - 0.0998). In the delayed induction group, 74% of the patients went into spontaneous labour during the conservative management period. Patients in the active group (immediate induction) had a statistically significant better chance of being discharged within 48 hours of admission (P = 0.028; odds ratio = 3.34; 95% confidence limits = 1.12 -10.73).Conclusions. The management of patients with premature rupture of the membranes after 34 weeks should be decided upon according to the level of antepartum and neonatal care which is available at the particular unit. Where there is adequate neonatal support and pressure on bed occupancy, immediate induction of labour should be considered, while peripheral units should consider conservative management before referral of patients

The impact of an electricity generation tax on the South African economy

In the 2008 budget of the Minister of Finance, the South African Government proposed to impose a 2 cents/kilowatt-hour (c/kWh) tax on the sale of electricity generated from non-renewable sources; this tax is to be collected at source by the producers/generators of electricity. The intention of this measure is to serve a dual purpose of protecting the environment and helping to manage the current electricity supply shortages by reducing demand. The objective here is to evaluate the impact of such an electricity generation tax on the South African, SACU and SADC economies. The paper firstly considers the theoretical foundations of an electricity generation tax supported by international experiences in this regard. This section also contrasts the suitability of a permit with a tax system to achieve CO2 emission reduction. We subsequently apply the Global Trade Analysis Project (GTAP) model to evaluate the impact of an electricity generation tax on the South African, SACU and SADC economies. We simulate the proposed tax as a 10 percent increase in the output price of electricity. We assume a closure rule that allows unskilled labour to migrate and a limited skilled workforce. As expected, the electricity generation tax will reduce demand. Due to the decrease in domestic demand, export volume increases and import volume decreases, this is despite a weaker terms of trade. We also found that unemployment for unskilled labour increases and wages of skilled workers are expected to decrease. A unilateral electricity generation tax will benefit other SACU and SADC countries through an improvement in relative competitiveness, as shown by the improvement of the terms of trade for these regions. If, however, the benefits of pollution abatement are internalised, then electricity generation tax is expected to yield a positive effect on the South African economy.

A framework for assessing the performance of pulsar search pipelines

In this paper, we present a framework for assessing the effect of non-stationary Gaussian noise and radio frequency interference (RFI) on the signal to noise ratio, the number of false positives detected per true positive and the sensitivity of standard pulsar search pipelines. The results highlight the necessity to develop algorithms that are able to identify and remove non-stationary variations from the data before RFI excision and searching is performed in order to limit false positive detections. The results also show that the spectrum whitening algorithms currently employed, severely affect the effciency of pulsar search pipelines by reducing their sensitivity to long period pulsars.IS