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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2005.10.013 Byline: K. Wunnemann (a), G.S. Collins (b), H.J. Melosh (a) Keywords: Cratering; Impact processes; Collisional physics; Surfaces; comets Abstract: Numerical modelling of impact cratering has reached a high degree of sophistication; however, the treatment of porous materials still poses a large problem in hydrocode calculations. We present a novel approach for dealing with porous compaction in numerical modelling of impact crater formation. In contrast to previous attempts (e.g., P-alpha model, snowplow model), our model accounts for the collapse of pore space by assuming that the compaction function depends upon volumetric strain rather than pressure. Our new E-alpha model requires only four input parameters and each has a physical meaning. The model is simple and intuitive and shows good agreement with a wide variety of experimental data, ranging from static compaction tests to highly dynamic impact experiments. Our major objective in developing the model is to investigate the effect of porosity and internal friction on transient crater formation. We present preliminary numerical model results that suggest that both porosity and internal friction play an important role in limiting crater growth over a large range in gravity-scaled source size. Author Affiliation: (a) Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, USA (b) IARC, Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom Article History: Received 14 June 2005; Revised 18 October 2005

A systematic review and meta-analysis compared the performance of the ADNEX model and the RMI in diagnosing ovarian malignancy. The study included 10 studies from 14 countries and 27 centers, with a total of 7700 tumors. The ADNEX model had higher discrimination between benign and malignant tumors compared to RMI, with a pooled AUC ranging from 0.91 to 0.94 for ADNEX and 0.84 to 0.89 for RMI. ADNEX was found to be clinically useful in supporting decision-making, with a p(useful) ranging from 92% to 99%, while the clinical utility of RMI was significantly lower. [Extracted from the article]

Early identification of ovarian cancer is an unresolved challenge and the predictive value of single symptoms is limited. We evaluated the performance of QCancer® ( Ovarian) prediction model for predicting the risk of ovarian cancer in a UK cohort of general practice patients. A total of 1.1 million patients registered with a general practice surgery between 1 January 2000 and 30 June 2008, aged 30-84 years with 735 ovarian cancer cases, were included in the analysis. Ovarian cancer was defined as incident diagnosis of ovarian cancer during the 2 years after study entry. The results from this independent and external validation of QCancer® ( Ovarian) prediction model demonstrated good performance on a large cohort of general practice patients. QCancer® ( Ovarian) had very good discrimination with an area under the receiver operating characteristic curve of 0.86 and explained 59.9% of the variation. QCancer® ( Ovarian) was well calibrated across all tenths of risk and over all age. The 10% of women with the highest predicted risks included 64% of all ovarian cancer diagnoses over the next 2 years. QCancer® ( Ovarian) appears to be a useful tool for identifying undetected cases of ovarian cancer in primary care in the UK for early referral and investigation. [ABSTRACT FROM AUTHOR]

Abstract: We describe improvements to the ɛ-α porous compaction model for simulating solar system impacts. To improve the treatment of highly porous materials, we modified the ɛ-α model to account for thermal expansion of the matrix during compaction. We validated the improved model by demonstrating good agreement between numerically computed Hugoniot curves for porous iron (up to initial porosities of ∼80%) using the improved ɛ-α model and experimentally-derived Hugoniot data. Moreover, we verified that the model improvements are easily implemented into a hydrocode and preserve the efficiency advantage of a strain-based compaction function. We used the improved ɛ-α porous compaction model in the iSALE hydrocode to reproduce 2-km/s porous-target laboratory impact experiments. The simulation results were in qualitative agreement with the experiments but produced craters that were consistently deeper and larger in volume than the experiments. The results of the hydrocode simulations and laboratory experiments show a reduction in crater efficiency with increasing porosity. This reduction is more dramatic if the impactor density and velocity are higher. [Copyright &y& Elsevier]

Abstract: Graphical methods are becoming increasingly used to monitor adverse outcomes from surgical interventions. However, uptake of such methods has largely been in the area of cardiothoracic surgery or in transplants with relatively little impact made in surgical oncology. A number of the more commonly used graphical methods including the Cumulative Mortality plot, Variable Life-Adjusted Display, Cumulative Sum (CUSUM) and funnel plots will be described. Accounting for heterogeneity in case-mix will be discussed and how ignoring case-mix can have considerable consequences. All methods will be illustrated using data from the Scottish Audit of Gastro-Oesophageal Cancer services (SAGOCS) data set. [Copyright &y& Elsevier]

Meteor Crater in Arizona was the first terrestrial structure to be widely recognized as a meteorite impact scar and has probably been more intensively studied than any other impact crater on Earth. We have discovered something surprising about its mode of formation-namely that the surface-impact velocity of the iron meteorite that created Meteor Crater was only about 12 km s-1. This is close to the 9.4 km s-1 minimum originally proposed but far short of the 15-20 km s-1 that has been widely assumed-a realization that clears up a long-standing puzzle about why the crater does not contain large volumes of rock melted by the impact. [ABSTRACT FROM AUTHOR]

• Projectiles with similar contact surface area have minimal effects on cratering. • The projectile geometry mostly influences the ejection angle of the fast ejecta. • Projectiles with elongated different surface areas create elliptical craters. • Projectile geometry caused a variation in the momentum enhancement by up to 10%. • LICIACube might observe the projectile geometry effects in the impact ejecta plume. The DART spacecraft will impact Didymos's secondary, Dimorphos, at the end of 2022 and cause a change in the orbital period of the secondary. For simplicity, most previous numerical simulations of the impact used a spherical projectile geometry to model the DART spacecraft. To investigate the effects of alternative, simple projectile geometries on the DART impact outcome we used the iSALE shock physics code in two and thee-dimensions to model vertical impacts of projectiles with a mass and speed equivalent to the nominal DART impact, into porous basalt targets. We found that the simple projectile geometries investigated here have minimal effects on the crater morphology and momentum enhancement. Projectile geometries modelled in two-dimensions that have similar surface areas at the point of impact, affect the crater radius and the crater volume by less than 5%. In the case of a more extreme projectile geometry (i.e., a rod, modelled in three-dimensions), the crater was elliptical and 50% shallower compared to the crater produced by a spherical projectile of the same momentum. The momentum enhancement factor in these test cases, commonly referred to as β , was within 7% for the 2D simulations and within 10% for the 3D simulations, of the value obtained for a uniform spherical projectile. The most prominent effects of projectile geometry are seen in the ejection velocity as a function of launch position and ejection angle of the fast ejecta that resides in the so-called 'coupling zone'. These results will inform the LICIACube ejecta cone analysis. [ABSTRACT FROM AUTHOR]