New thinking

The traditional practice of medicine provides an excellent model of our thinking behavior. A child is brought into the clinic by his mother. The child has a rash. The doctor thinks of a range of possibilities from food allergy to measles. The doctor then makes a judgement or diagnosis based on signs, symptoms, history, tests (to exclude other possibilities), environmental factors, etc. If the doctor judges the condition to be measles then the probable course of the illness is known, as are the possible complications and the traditional treatment. This is an excellent and effective system.peer-reviewe

How does diabetes cause coronary artery disease?

From the cardiologist’s viewpoint, diabetes increases the rate of development of coronary atheroma, increases the risk of a coronary thrombosis, and has a deleterious effect on the outcome of myocardial infarction. In this article the author describes the risk factors associated with diabetes and concentrate on ways which diabetes may accelerate atheroma.peer-reviewe

The direct teaching of thinking as a skill

The teaching of thinking as a skill is not tomorrow's dream but today's reality, claims one of the world's foremost experts on the topic. He describes his methods for teaching "the generalizable skill of thinking" - methods that have been used from the jungles of South America to the boardrooms of major corporations.peer-reviewe

Clustering of Local Group distances: publication bias or correlated measurements? V. Galactic rotation constants

As part of on an extensive data mining effort, we have compiled a database of 162 Galactic rotation speed measurements at $R_0$ (the solar Galactocentric distance), $\Theta_0$. Published between 1927 and 2017 June, this represents the most comprehensive set of $\Theta_0$ values since the 1985 meta analysis that led to the last revision of the International Astronomical Union's recommended Galactic rotation constants. Although we do not find any compelling evidence of the presence of `publication bias' in recent decades, we find clear differences among the $\Theta_0$ values and the $\Theta_0/R_0$ ratios resulting from the use of different tracer populations. Specifically, young tracers (including OB and supergiant stars, masers, Cepheid variables, H{\sc ii} regions, and young open clusters), as well as kinematic measurements of Sgr A* near the Galactic Center, imply a significantly larger Galactic rotation speed at the solar circle and a higher $\Theta_0/R_0$ ratio (i.e., $\Theta_0 = 247 \pm 3$ km s$^{-1}$ and $\Theta_0/R_0 = 29.81 \pm 0.32$ km s$^{-1}$ kpc$^{-1}$; statistical uncertainties only) than any of the tracers dominating the Galaxy's mass budget (i.e., field stars and the H{\sc i}/CO distributions). Using the latter as most representative of the bulk of the Galaxy's matter distribution, we arrive at an updated set of Galactic rotation constants, \Theta_0 = 225 \pm 3 \mbox{ (statistical)} \pm 10 \mbox{ (systematic) km s}^{-1}, R_0 = 8.3 \pm 0.2 \mbox{ (statistical)} \pm 0.4 \mbox{ (systematic) kpc}, and \Theta_0 / R_0 = 27.12 \pm 0.39 \mbox{ (statistical)} \pm 1.78 \mbox{ (systematic) km s}^{-1} \mbox{ kpc}^{-1}.Comment: 8 pages, 4 figures; ApJS, in pres

Clustering of Local Group distances: publication bias or correlated measurements? III. The Small Magellanic Cloud

Aiming at providing a firm mean distance estimate to the Small Magellanic Cloud (SMC), and thus to place it within the internally consistent Local Group distance framework we recently established, we compiled the current-largest database of published distance estimates to the galaxy. Based on careful statistical analysis, we derive mean distance estimates to the SMC using eclipsing binary systems, variable stars, stellar population tracers, and star cluster properties. Their weighted mean leads to a final recommendation for the mean SMC distance of $(m-M)_0^{\rm SMC} = 18.96 \pm 0.02$ mag, where the uncertainty represents the formal error. Systematic effects related to lingering uncertainties in extinction corrections, our physical understanding of the stellar tracers used, and the SMC's complex geometry---including its significant line-of-sight depth, its irregular appearance which renders definition of the galaxy's center uncertain, as well as its high inclination and possibly warped disk---may contribute additional uncertainties possibly exceeding 0.15--0.20 mag.Comment: 17 pages, 2 figures (emulateapj format); AJ, in pres

Clustering of Local Group distances: publication bias or correlated measurements? II. M31 and beyond

The accuracy of extragalactic distance measurements ultimately depends on robust, high-precision determinations of the distances to the galaxies in the local volume. Following our detailed study addressing possible publication bias in the published distance determinations to the Large Magellanic Cloud (LMC), here we extend our distance range of interest to include published distance moduli to M31 and M33, as well as to a number of their well-known dwarf galaxy companions. We aim at reaching consensus on the best, most homogeneous, and internally most consistent set of Local Group distance moduli to adopt for future, more general use based on the largest set of distance determinations to individual Local Group galaxies available to date. Based on a careful, statistically weighted combination of the main stellar population tracers (Cepheids, RR Lyrae variables, and the magnitude of the tip of the red-giant branch), we derive a recommended distance modulus to M31 of $(m-M)_0^{\rm M31} = 24.46 \pm 0.10$ mag---adopting as our calibration an LMC distance modulus of $(m-M)_0^{\rm LMC} = 18.50$ mag---and a fully internally consistent set of benchmark distances to key galaxies in the local volume, enabling us to establish a robust and unbiased, near-field extragalactic distance ladder.Comment: AJ, in press; 32 pages in AASTeX preprint format, 6 postscript figures. For online database, see http://astro-expat.info/Data/pubbias.htm

Clustering of Local Group distances: publication bias or correlated measurements? VII. A distance framework out to 100 Mpc

We consider the published distance moduli to the Fornax and Coma galaxy clusters, with emphasis on the period since 1990. We have carefully homogenized our catalogs of distance moduli onto the distance scale established in the previous papers in this series. We assessed systematic differences associated with the use of specific tracers, and discarded results based on application of the Tully--Fisher relation and of globular cluster and planetary nebula luminosity functions. We recommend `best' weighted relative distance moduli for the Fornax and Coma clusters with respect to the Virgo cluster of $\Delta (m-M)_0^{\rm Fornax - Virgo} = 0.18 \pm 0.28$ mag and $\Delta (m-M)_0^{\rm Coma - Virgo} = 3.75 \pm 0.23$ mag. The set of weighted mean distance moduli (distances) we derived as most representative of the clusters' distances is, \begin{eqnarray} (m-M)_0^{\rm Fornax} &=& 31.41 \pm 0.15 \mbox{ mag } (D = 19.1^{+1.4}_{-1.2} \mbox{ Mpc) and} \nonumber &=& 31.21 \pm 0.28 \mbox{ mag } (D = 17.5^{+2.4}_{-2.2} \mbox{ Mpc)}; \nonumber \\ (m-M)_0^{\rm Coma} &=& 34.99 \pm 0.38 \mbox{ mag } (D = 99.5^{+19.0}_{-15.9} \mbox{ Mpc) and} \nonumber &=& 34.78 \pm 0.27 \mbox{ mag } (D = 90.4^{+11.9}_{-10.6} \mbox{ Mpc)}, \nonumber \end{eqnarray} where the first value for each cluster is the result of our analysis of the direct distance moduli, while the second modulus is based on distance moduli relative to the Virgo cluster. The absolute and relative distance moduli for both clusters are mutually consistent within the uncertainties; the relative distance moduli yield shorter distances by $\sim$1$\sigma$. Lingering uncertainties in the underlying absolute distance scale appear to have given rise to a systematic uncertainty on the order of 0.20 mag.Comment: 15 pages, 3 figures; accepted for publication in ApJ

A rare case of an idiopathic extraocular muscle abscess

Diplopia has a diverse range of ophthalmological, neurological, autoimmune, neoplastic and infectious causes. However it is very rare for an extraocular muscle abscess to occur. A skeletal muscle abscess usually occurs in the thigh and trunk muscles and is most commonly caused by Staphylococcus aureus.1 The purpose of this case report is to describe this condition we came across in our eye casualty department in a healthy teenager who presented with painful diplopia and this was due to a lateral rectus muscle abscess. Complete resolution of the diplopia occurred by 6 weeks from starting treatment. The possible aetiologies and possible complications of such a condition are then discussed. An idiopathic extraocular muscle abscess is a rare condition which should be included in the differential diagnosis of a patient presenting with painful double vision.peer-reviewe

The changing face of cancer therapeutics improved : outcome and decreased toxicity with Molecular Targeted Drugs

The treatment of patients with cancer has largely involved the administration of cytotoxic drugs with narrow therapeutic indices, with little selectivity for cancer cells over normal proliferating cells. The primary exception to this has been the successful administration of hormonal manipulation to treat breast and prostate malignancies. The development of hormonal manipulation arose from the observation by Sir George Beatson that breast carcinomas improved after bilateral oophorectomy. This led to the use of Tamoxifen and more recently aromatase inhibitors and oestrogen receptor antagonists. These targeted therapeutics are characterised by their ability to induce selective tumour cell death and achieve patient benefit with low toxicity, and have had a significant impact on the outcome of patients with early and advanced oestrogen receptor positive breast cancer. Further advances in the understanding of tumour cell biology, the sequencing of the human genome, and the characterisation of the molecular differences between malignant and normal cells have, over the past two decades, resulted in the identification of a large number of critically important molecular targets. As with the identification of the importance of oestrogens and the oestrogen receptor, this has accelerated the development of molecularly targeted therapeutics and is rapidly revolutionising cancer medicine (Table 1). This brief review will describe some of the most important advances achieved and will attempt to predict what future cancer therapeutics will entail.peer-reviewe