Evolution of the Dust Coma in Comet 67P/Churyumov-Gerasimenko Before 2009 Perihelion

Comet 67P/Churyumov-Gerasimenko is the main target of ESA's Rosetta mission and will be encountered in May 2014. As the spacecraft shall be in orbit the comet nucleus before and after release of the lander {\it Philae}, it is necessary necessary to know the conditions in the coma. Study the dust environment, including the dust production rate and its variations along its preperihelion orbit. The comet was observed during its approach to the Sun on four epochs between early-June 2008 and mid-January 2009, over a large range of heliocentric distances that will be covered by the mission in 2014. An anomalous enhancement of the coma dust density was measured towards the comet nucleus. The scalelength of this enhancement increased with decreasing heliocentric distance of the comet. This is interpreted as a result of an unusually slow expansion of the dust coma. Assuming a spherical symmetric coma, the average amount of dust as well as its ejection velocity have been derived. The latter increases exponentially with decreasing heliocentric distance (\rh), ranging from about 1 m/s at 3 AU to about 25-35 m/s at 1.4 AU. Based on these results we describe the dust environment at those nucleocentric distances at which the spacecraft will presumably be in orbit. Astronomy and Astrophysics, in pressComment: 5 pages, 4 figure

2P/Encke, the Taurid complex NEOs and the Maribo and Sutter’s Mill meteorites

Aims. 2P/Encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200 years. The Taurid meteoroid stream has long been linked with 2P/Encke owing to a good match of their orbital elements, even though the comet’s activity is not strong enough to explain the number of observed meteors. Various small near-Earth objects (NEOs) have been discovered with orbits that can be linked to 2P/Encke and the Taurid meteoroid stream. Maribo and Sutter’s Mill are CM type carbonaceous chondrite that fell in Denmark on January 17, 2009 and April 22, 2012, respectively. Their pre-atmospheric orbits place them in the middle of the Taurid meteoroid stream, which raises the intriguing possibility that comet 2P/Encke could be the parent body of CM chondrites. Methods. To investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs, and CM chondrites exists, we performed photometric and spectroscopic studies of these objects in the visible wavelength range. We observed 2P/Encke and 10 NEOs on August 2, 2011 with the FORS instrument at the 8.2 m Very Large Telescope on Cerro Paranal (Chile). Results. Images in the R filter, used to investigate the possible presence of cometary activity around the nucleus of 2P/Encke and the NEOs, show that no resolved coma is present. None of the FORS spectra show the 700 nm absorption feature due to hydrated minerals that is seen in the CM chondrite meteorites. All objects show featureless spectra with moderate reddening slopes at λ10 and 1999 VT25, which show a flatter spectrum, the spectral slope of the observed NEOs is compatible with that of 2P/Encke. However, most of the NEOs show evidence of a silicate absorption in lower S/N data at λ> 800 nm, which is not seen in 2P/Encke, which suggests that they are not related. Conclusions. Despite similar orbits, we find no spectroscopic evidence for a link between 2P/Encke, the Taurid complex NEOs and the Maribo and Sutter’s Mill meteorites. However, we cannot rule out a connection to the meteorites either, as the spectral differences may be caused by secondary alteration of the surfaces of the NEOs

Rotation of Cometary Nuclei New Lightcurves and an Update of the Ensemble Properties of Jupiter-Family Comets

We report new lightcurves and phase functions for nine Jupiter-family comets (JFCs). They were observed in the period 2004-2015 with various ground telescopes as part of the Survey of Ensemble Physical Properties of Cometary Nuclei (SEPPCoN) as well as during devoted observing campaigns. We add to this a review of the properties of 35 JFCs with previously published rotation properties. The photometric time-series were obtained in Bessel R, Harris R and SDSS r' filters and were absolutely calibrated using stars from the Pan-STARRS survey. This specially-developed method allowed us to combine data sets taken at different epochs and instruments with absolute-calibration uncertainty down to 0.02 mag. We used the resulting time series to improve the rotation periods for comets 14P/Wolf, 47P/Ashbrook-Jackson, 94P/Russell, and 110P/Hartley 3 and to determine the rotation rates of comets 93P/Lovas and 162P/Siding-Spring for the first time. In addition to this, we determined the phase functions for seven of the examined comets and derived geometric albedos for eight of them. We confirm the known cut-off in bulk densities at $\sim$0.6 g $\mathrm{cm^{-3}}$ if JFCs are strengthless. Using the model of Davidsson (2001) for prolate ellipsoids with typical density and elongations, we conclude that none of the known JFCs require tensile strength larger than 10-25 Pa to remain stable against rotational instabilities. We find evidence for an increasing linear phase function coefficient with increasing geometric albedo. The median linear phase function coefficient for JFCs is 0.046 mag/deg and the median geometric albedo is 4.2 per cent.Comment: 38 pages, accepted for publication in MNRA

Structure and dynamics of ring polymers: entanglement effects because of solution density and ring topology

The effects of entanglement in solutions and melts of unknotted ring polymers have been addressed by several theoretical and numerical studies. The system properties have been typically profiled as a function of ring contour length at fixed solution density. Here, we use a different approach to investigate numerically the equilibrium and kinetic properties of solutions of model ring polymers. Specifically, the ring contour length is maintained fixed, while the interplay of inter- and intra-chain entanglement is modulated by varying both solution density (from infinite dilution up to \approx 40 % volume occupancy) and ring topology (by considering unknotted and trefoil-knotted chains). The equilibrium metric properties of rings with either topology are found to be only weakly affected by the increase of solution density. Even at the highest density, the average ring size, shape anisotropy and length of the knotted region differ at most by 40% from those of isolated rings. Conversely, kinetics are strongly affected by the degree of inter-chain entanglement: for both unknots and trefoils the characteristic times of ring size relaxation, reorientation and diffusion change by one order of magnitude across the considered range of concentrations. Yet, significant topology-dependent differences in kinetics are observed only for very dilute solutions (much below the ring overlap threshold). For knotted rings, the slowest kinetic process is found to correspond to the diffusion of the knotted region along the ring backbone.Comment: 17 pages, 11 figure

The Re-Emergence of Percutaneous Fasciotomy in the Management of Dupuytren’s Disease

Dupuytren’s disease is a common condition. Its management has gradually evolved but still remains a source of much controversy. Recently there has been a resurgence in the popularity of percutaneous needle fasciotomy. It is a simple method that uses a hypodermic needle as a scalpel blade. It is usually performed in the out-patient setting under local anaesthesia without a tourniquet. It has few complications and allows almost immediate return to work with few restrictions

Recombinant human erythropoietin in the treatment of chemotherapy-induced anemia and prevention of transfusion requirement associated with solid tumors: A randomized, controlled study

Background: Anemia is a common side effect of anticancer chemotherapy. Blood transfusion, previously the only available treatment for chemotherapy-induced anemia, may result insome clinical or subclinical adverse effects in the recipients. Recombinant human erythropoietin (rhEPO) provides a new treatment modality for chemotherapy-induced anemia. Patients and methods: To evaluate the effect of rhEPO onthe need for blood transfusions and on hemoglobin (Hb)concentrations, 227 patients with solid tumors and chemotherapy-induced anemia were enrolled in a randomized, controlled, clinical trial. Of 189 patients evaluable for efficacy, 101 received 5000 IU rhEPO daily s.c, while 88 patients received no treatment during the 12-week controlled phase of the study. Results: The results demonstrate a statistically significant reduction in the need for blood transfusions (28% vs. 42%, P = 0.028) and in the mean volume of packed red blood cells transfused (152 ml vs. 190 ml, p = 0.044) in patients treated with rhEPO compared to untreated controls. This effect was even more pronounced in patients receiving platinum-based chemotherapy (26% vs. 45%, % 0.038). During the controlled treatment phase, the median Hb values increased in the rhEPO patients while remaining unchanged in the control group. The response was seen in all tumor types. Conclusions: RhEPO administration at a dose of 5000 IU daily s.c. increases hemoglobin levels and reduces transfusionrequirements in chemotherapy-induced anemia, especially during platinum-based chemotherap

Dose-response study of ibandronate in the treatment of cancer-associated hypercalcaemia.

Hypercalcaemia is an important cause of morbidity in malignant disease. We studied the efficacy and safety of intravenous ibandronate (a new, potent bisphosphonate) in a multicentre study of 147 patients with severe cancer-associated hypercalcaemia which had been resistant to treatment with rehydration alone. Of 131 randomized patients who were eligible for evaluation, 45 were allocated to receive 2 mg ibandronate, 44 patients to receive 4 mg and 42 patients to receive 6 mg. Serum calcium values fell progressively in each group from day 2, reaching a nadir at day 5, and in some patients normocalcaemia was maintained for up to 36 days after treatment. The 2-mg dose was significantly less effective than the 4-mg or 6-mg dose in correcting hypercalcaemia, as the number of patients who achieved serum calcium values below 2.7 mM after treatment was 50% in the 2-mg group compared with 75.6% in the 4-mg group and 77.4% in the 6-mg group (P < 0.05; 2 mg vs others). In a logistic regression analysis, three factors were found to predict response; ibandronate dose (higher doses were more effective), severity of presenting hypercalcaemia (severe hypercalcaemia was associated with less complete response) and tumour type (patients with breast carcinoma and haematological tumours responded better than those with other tumours). Ibandronate was generally well tolerated and no serious drug-related adverse events were observed. We conclude that ibandronate is a safe, well tolerated and effective treatment for cancer-associated hypercalcaemia, which should prove a useful addition to the current range of therapies available to treat this condition

Numerical study of linear and circular model DNA chains confined in a slit: metric and topological properties

Advanced Monte Carlo simulations are used to study the effect of nano-slit confinement on metric and topological properties of model DNA chains. We consider both linear and circularised chains with contour lengths in the 1.2--4.8 $\mu$m range and slits widths spanning continuously the 50--1250nm range. The metric scaling predicted by de Gennes' blob model is shown to hold for both linear and circularised DNA up to the strongest levels of confinement. More notably, the topological properties of the circularised DNA molecules have two major differences compared to three-dimensional confinement. First, the overall knotting probability is non-monotonic for increasing confinement and can be largely enhanced or suppressed compared to the bulk case by simply varying the slit width. Secondly, the knot population consists of knots that are far simpler than for three-dimensional confinement. The results suggest that nano-slits could be used in nano-fluidic setups to produce DNA rings having simple topologies (including the unknot) or to separate heterogeneous ensembles of DNA rings by knot type.Comment: 12 pages, 10 figure

Persistence of anal squamous intraepithelial lesions and anal HPV infection in HIV-infected patientsdespite immune restoration under cART

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