The anomaly in the candidate microlensing event PA-99-N2

The light curve of PA-99-N2, one of the recently announced microlensing candidates toward M31, shows small deviations from the standard Paczynski form. We explore a number of possible explanations, including correlations with the seeing, the parallax effect, and a binary lens. We find that the observations are consistent with an unresolved red giant branch or asymptotic giant branch star in M31 being microlensed by a binary lens. We find that the best-fit binary lens mass ratio is similar to1.2x10(-2), which is one of the most extreme values found for a binary lens so far. If both the source and lens lie in the M31 disk, then the standard M31 model predicts the probable mass range of the system to be 0.02-3.6 M-circle dot (95% confidence limit). In this scenario, the mass of the secondary component is therefore likely to be below the hydrogen-burning limit. On the other hand, if a compact halo object in M31 is lensing a disk or spheroid source, then the total lens mass is likely to lie between 0.09 and 32 M-circle dot, which is consistent with the primary being a stellar remnant and the secondary being a low-mass star or brown dwarf. The optical depth (or, alternatively, the differential rate) along the line of sight toward the event indicates that a halo lens is more likely than a stellar lens, provided that dark compact objects comprise no less than 15% (or 5%) of halos.

A candidate M31/M32 intergalactic microlensing event

We report the discovery of a microlensing candidate projected 2'54

A short-timescale candidate microlensing event in the point-agape pixel lensing survey of M31

We report the discovery of a short-duration microlensing candidate in the northern field of the POINT-AGAPE pixel lensing survey toward M31. Almost certainly, the source star has been identified on Hubble Space Telescope archival images, allowing us to infer an Einstein crossing time of t(E) = 10.4 days, a maximum magnification of A(max) similar to 18, and a lens-source proper motion mu (rel) > 0.3 mu as day(-1). The event has a projected separation of 8' from the center of M31, beyond the bulk of the stellar lens population. There are three plausible identifications/locations for the lensing object: a massive compact halo object (MACHO) in either M31 or the Milky Way, or a star in the M31 disk. The most probable mass is 0.06 M-. for an M31 MACHO, 0.02 M-. for a Milky Way MACHO, and 0.2 M-. for an M31 stellar lens. While the stellar interpretation is possible, the MACHO interpretation is the most probable for halo fractions above 20%.

Adverse reactions to drugs: in vitro studies with isolated cells

Objective and design: Drug-induced adverse reactions can be allergic or pseudoallergic in nature, in this study the histamine releasing ability of 4 radiographic contrast media and 2 opioid analgesics was tested on a variety of mast cell containing cell suspensions.

Adequacy of reporting monitoring regimens of risk factors for cardiovascular disease in clinical guidelines: systematic review

Objective To assess the reporting of monitoring recommendations in guidelines on the prevention and treatment of cardiovascular disease.

A systematic review of quantitative studies reporting selected patient experienced outcomes, with a specific focus on gender differences in people with colorectal cancer

Men with colorectal cancer have a higher mortality rate than their female counterparts. Despite this, there is a limited understanding of the impact gender has on the experience of colorectal cancer.

The UK Renal Registry Advanced CKD Study: frequency of incorrect reporting of date of start of RRT

Background: A preliminary review of the UK Renal Registry (UKRR) pre-RRT study data revealed results suggesting that, for some patients, the date of start of renal replacement therapy (RRT), as reported to the UKRR, was incorrect and often significantly later than the true date of start. A more detailed study then aimed to validate a set of criteria to identify patients with an incorrect start date. Methods: Pre-RRT laboratory data were electronically extracted from 8,810 incident RRT patients from 9 UK renal centres. Any patient with a low urea (<15 mmol/L) at the start of RRT or with a substantial improvement in kidney function (either a fall in urea >10 mmol/L or rise in eGFR >2 ml/min/1.73 m) within the two months prior to RRT were considered to potentially have an incorrect date of start. In 4
selected centres, the electronic patient records of all patients flagged were reviewed to validate these criteria.
Results: Of 8,810 patients, 1,616 (18.3%) were flagged by the identification criteria as having a potentially incorrect date of start of RRT, although a single centre accounted for 41% of the total flagged cohort. Of these flagged patients, 61.7% had been assigned an incorrect date of start of haemodialysis (HD), 5.7% had evidence of acute RRT being given before the reported date of start of HD
and 9.2% had evidence of starting peritoneal dialysis exchanges prior to the reported date of start. Of
those flagged, 10.7% had a correct date of start of RRT.
Conclusions: Accurate reporting of RRT episodes is vital for the analysis of time dependent studies such as survival or time to transplantation. A proportion of patients starting RRT were assigned an incorrect start date. In order to improve the accuracy of this reporting the UK Renal Registry
must work with renal centres and clinical staff on improving data input for the start of RRT.