Inflation, Money Demand, and Purchasing Power Parity in South Africa

This empirical study for South Africa indicates that there exists a stable money demand type of relationship among domestic prices, broad money, real income, and interest rates, as well as a long-run relationship among domestic prices, foreign prices, and the nominal exchange rate. In the short run, shocks to the nominal exchange rate affect domestic prices but have virtually no impact on real output, while shocks to broad money have a temporary impact on real output before becoming inflationary. Both types of shocks seem to trigger a monetary policy response, as the short-term interest rate adjusts quickly. Copyright 2001, International Monetary Fund

Dynamic Gains from Trade: Evidence from South Africa

This paper examines the empirical relationship between trade and total factor productivity (TFP) in South Africa. Using data on actual trade protection across different manufacturing sectors, it is shown that trade liberalization had a positive impact on TFP growth during the 1990s. In addition, time-series evidence on macro data supports a positive long-run relationship between TFP and openness. Copyright 2001, International Monetary Fund

Radiating Effectiveness of Annular-Finned Space Radiators, Including Mutual Irradiation between Radiator Elements

the authors also provide an approximate quantitative number for the accuracy of the numerical results. Based on the authors' results of Figs. 8 and 9, the fully developed periodic flow is achieved at x/L = 4 and 30 for Re = 200 and 1600 respectively for L/H = 1. Would the authors first quantitatively define the periodic fully developed flow, and then provide the tabular values of x/L as functions of L/H and Re for L/H = 0.2,0.5,1,2 and 5, and the covered range of Re. A research task remains further refining the analytical model to correlate better the performance of interrupted wall surface with the experimental results. Subsequently, the more complex heat exchanger surfaces could be analyzed. In the meanwhile, this paper by Prof. Sparrow and his colleagues serves as a reminder that the flow and heat transfer phenomena in a compact heat exchanger are too complex to analyze. A better quantitative understanding of the flow phenomena is essential for better correlations and improved heat exchanger design. Additional Reference Authors' Closure We are appreciative of the perspectives conveyed by Dr. Shah's Discussion. With regard to the role of vortices and wakes, there are, assuredly, conditions where they will affect both the heat transfer and friction. On the other hand, there are conditions for which no significant effect will be felt. Perspectives on these conditions are conveyed in references [11] and [12]. In connection with the identification of the periodically developed regime in Figs. 8 and 9, there is considerable latitude depending on the selected criterion. Since all portions of a velocity or temperature profile do not develop with equal rapidity, there are various criteria that can be employed. It was for this reason that we did not quote development lengths in the paper. Additional References 11 Kottke, V., Blenke, H., and Schmidt, K. G., "The Influence of Nose Section and Turbulence Intensity on the Flow Around Thick Plates in Parallel Flow," Warme-und Stoffubertragung, Vol. 10,1977, pp. 159-174. 12 Loehrke, R. I., Roadman, R. E., and Read, G. W" ASME Paper The purpose of this discussion is to point out how one of Minning's results can be generalized. In his analysis of the inverted conical frustrum, Minning has chosen to express his results in terms of four variables-the cone half angle fi, the height of the frustrum h, the radial location of the differential element p, and the vertical distance from the differential element to the extended frustrums' vertex s. In my view, this last choice is not the natural one and indeed it obscures the generality of the result expressed by equation It appears that a better choice of variable would be the radius of the frustrum in the plane of the element or ring, which is given by r = -s tan fi. If s is thereby eliminated from equation With respect to this latter point, one may note, as was done for a cylinder by Sparrow, et al. [1] that the shape factor in question can be considered as the sum of two parts-one being a circular segment and, in this case, the other being a tilted triangular plate frustrum. 1 By C. P. Minning, published in the August, 1977 issue of the JOURNAL OP HEAT TRANSFER, Vol. 99, No. 3, The Aerospace Corporation, El Segundo, CA 90245. Since the former is known [2], the latter can be readily obtained and subsequently expressed in variables more suitable for that configuration. This, of course, introduces new possibilities too numerous to mention. Finally, since Minning does not mention any analytical checks of his result, it is pointed out that, when /3 = 0, it reduces to a form equivalent to that for the cylinder [1]. Additional References 1 Sparrow, E. M., Miller, G. B., and Jonsson, V. K., "Radiating Effectiveness of Annular-Finned Space Radiators, Including Mutual Irradiation between Radiator Elements," Journal Aerospace Sciences, Vol. 29, 1962, pp. 1291-1299 2 Sparrow, E. M., "A New and Simpler Formulation for Radiative Angle Factors," ASME JOURNAL OF HEAT TRANSFER, Vol. 85,1963, pp. 81-88. Author's Closure I appreciate Dr. Nelson's pointing out that the applicability of equation An alternate expression that avoids this confusion can be derived by substitution of the relation r = -s tanjtf, as suggested by Dr. Nelson, and the relation a = (7r/2) -fi into equation C^)] [(h cot a + r) -In this expression, a is the angle between the plane of dAi and the sloping side of the conical frustrum. Values of a are always positive and lie in the range 0 < « < TT. For 0 < « < 7r/2, the frustrum opens upward away from the plane of dA\. For 7r/2 < a < w, the frustrum opens downward toward the plane of dAi. The special case, a = it 12

The effect of leisure-time physical activity on the risk of acute myocardial infarction depending on Body Mass Index: a population-based case-control study

BACKGROUND: High body mass index (BMI) and lack of physical activity have been recognized as important risk factors for coronary heart disease. The aim of the present study was to evaluate whether leisure-time physical activity compensates for the increased risk of acute myocardial infarction associated with overweight and obesity. METHODS: Data from the SHEEP (Stockholm Heart Epidemiology Program) study were used. The SHEEP study is a large Swedish population-based case-control study, comprising 1204 male and 550 female cases, and 1538 male and 777 female controls, conducted in Stockholm County, Sweden, during the period 1992–1994. Odds ratios (OR), together with 95 % confidence intervals (95% CI), were calculated using unconditional logistic regression, as estimates of the relative risks. RESULTS: Regular leisure-time physical activity was associated with a decreased risk of myocardial infarction among lean, normal-weight and overweight subjects, but not among obese subjects. Obese (BMI ≥ 30) and physically active persons had an almost twofold risk of myocardial infarction, compared with normal-weight and sedentary persons (OR 1.85, 95% CI 1.07–3.18). The results were similar for men and women. CONCLUSION: While regular leisure-time physical activity seems to provide protection against myocardial infarction among lean, normal-weight and overweight subjects, this does not appear to be the case in obese subjects

Longer First Introns Are a General Property of Eukaryotic Gene Structure

While many properties of eukaryotic gene structure are well characterized, differences in the form and function of introns that occur at different positions within a transcript are less well understood. In particular, the dynamics of intron length variation with respect to intron position has received relatively little attention. This study analyzes all available data on intron lengths in GenBank and finds a significant trend of increased length in first introns throughout a wide range of species. This trend was found to be even stronger when using high-confidence gene annotation data for three model organisms (Arabidopsis thaliana, Caenorhabditis elegans, and Drosophila melanogaster) which show that the first intron in the 5′ UTR is - on average - significantly longer than all downstream introns within a gene. A partial explanation for increased first intron length in A. thaliana is suggested by the increased frequency of certain motifs that are present in first introns. The phenomenon of longer first introns can potentially be used to improve gene prediction software and also to detect errors in existing gene annotations

Identification of a Novel Topoisomerase Inhibitor Effective in Cells Overexpressing Drug Efflux Transporters

BACKGROUND:Natural product structures have high chemical diversity and are attractive as lead structures for discovery of new drugs. One of the disease areas where natural products are most frequently used as therapeutics is oncology. METHOD AND FINDINGS:A library of natural products (NCI Natural Product set) was screened for compounds that induce apoptosis of HCT116 colon carcinoma cells using an assay that measures an endogenous caspase-cleavage product. One of the apoptosis-inducing compounds identified in the screen was thaspine (taspine), an alkaloid from the South American tree Croton lechleri. The cortex of this tree is used for medicinal purposes by tribes in the Amazonas basin. Thaspine was found to induce conformational activation of the pro-apoptotic proteins Bak and Bax, mitochondrial cytochrome c release and mitochondrial membrane permeabilization in HCT116 cells. Analysis of the gene expression signature of thaspine-treated cells suggested that thaspine is a topoisomerase inhibitor. Inhibition of both topoisomerase I and II was observed using in vitro assays, and thaspine was found to have a reduced cytotoxic effect on a cell line with a mutated topoisomerase II enzyme. Interestingly, in contrast to the topoisomerase II inhibitors doxorubicin, etoposide and mitoxantrone, thaspine was cytotoxic to cell lines overexpressing the PgP or MRP drug efflux transporters. We finally show that thaspine induces wide-spread apoptosis in colon carcinoma multicellular spheroids and that apoptosis is induced in two xenograft mouse models in vivo. CONCLUSIONS:The alkaloid thaspine from the cortex of Croton lechleri is a dual topoisomerase inhibitor effective in cells overexpressing drug efflux transporters and induces wide-spread apoptosis in multicellular spheroids

From monogenic to polygenic obesity: recent advances

The heritability of obesity and body weight in general is high. A small number of confirmed monogenic forms of obesity—the respective mutations are sufficient by themselves to cause the condition in food abundant societies—have been identified by molecular genetic studies. The elucidation of these genes, mostly based on animal and family studies, has led to the identification of important pathways to the disorder and thus to a deeper understanding of the regulation of body weight. The identification of inborn deficiency of the mostly adipocyte-derived satiety hormone leptin in extremely obese children from consanguineous families paved the way to the first pharmacological therapy for obesity based on a molecular genetic finding. The genetic predisposition to obesity for most individuals, however, has a polygenic basis. A polygenic variant by itself has a small effect on the phenotype; only in combination with other predisposing variants does a sizeable phenotypic effect arise. Common variants in the first intron of the ‘fat mass and obesity associated’ gene (FTO) result in an elevated body mass index (BMI) equivalent to approximately +0.4 kg/m² per risk allele. The FTO variants were originally detected in a genome wide association study (GWAS) pertaining to type 2 diabetes mellitus. Large meta-analyses of GWAS have subsequently identified additional polygenic variants. Up to December 2009, polygenic variants have been confirmed in a total of 17 independent genomic regions. Further study of genetic effects on human body weight regulation should detect variants that will explain a larger proportion of the heritability. The development of new strategies for diagnosis, treatment and prevention of obesity can be anticipated

Key signaling nodes in mammary gland development and cancer: β-catenin

β-Catenin plays important roles in mammary development and tumorigenesis through its functions in cell adhesion, signal transduction and regulation of cell-context-specific gene expression. Studies in mice have highlighted the critical role of β-catenin signaling for stem cell biology at multiple stages of mammary development. Deregulated β-catenin signaling disturbs stem and progenitor cell dynamics and induces mammary tumors in mice. Recent data showing deregulated β-catenin signaling in metaplastic and basal-type tumors suggest a similar link to reactivated developmental pathways and human breast cancer. The present review will discuss β-catenin as a central transducer of numerous signaling pathways and its role in mammary development and breast cancer

Present state and future perspectives of using pluripotent stem cells in toxicology research

The use of novel drugs and chemicals requires reliable data on their potential toxic effects on humans. Current test systems are mainly based on animals or in vitro–cultured animal-derived cells and do not or not sufficiently mirror the situation in humans. Therefore, in vitro models based on human pluripotent stem cells (hPSCs) have become an attractive alternative. The article summarizes the characteristics of pluripotent stem cells, including embryonic carcinoma and embryonic germ cells, and discusses the potential of pluripotent stem cells for safety pharmacology and toxicology. Special attention is directed to the potential application of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) for the assessment of developmental toxicology as well as cardio- and hepatotoxicology. With respect to embryotoxicology, recent achievements of the embryonic stem cell test (EST) are described and current limitations as well as prospects of embryotoxicity studies using pluripotent stem cells are discussed. Furthermore, recent efforts to establish hPSC-based cell models for testing cardio- and hepatotoxicity are presented. In this context, methods for differentiation and selection of cardiac and hepatic cells from hPSCs are summarized, requirements and implications with respect to the use of these cells in safety pharmacology and toxicology are presented, and future challenges and perspectives of using hPSCs are discussed

Combined Tevatron upper limit on gg->H->W+W- and constraints on the Higgs boson mass in fourth-generation fermion models

Report number: FERMILAB-PUB-10-125-EWe combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg→H→W+W- in pp̅ collisions at the Fermilab Tevatron Collider at √s=1.96  TeV. With 4.8  fb-1 of integrated luminosity analyzed at CDF and 5.4  fb-1 at D0, the 95% confidence level upper limit on σ(gg→H)×B(H→W+W-) is 1.75 pb at mH=120  GeV, 0.38 pb at mH=165  GeV, and 0.83 pb at mH=200  GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% confidence level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.Peer reviewe