Large Scale Image Segmentation with Structured Loss based Deep Learning for Connectome Reconstruction

We present a method combining affinity prediction with region agglomeration, which improves significantly upon the state of the art of neuron segmentation from electron microscopy (EM) in accuracy and scalability. Our method consists of a 3D U-NET, trained to predict affinities between voxels, followed by iterative region agglomeration. We train using a structured loss based on MALIS, encouraging topologically correct segmentations obtained from affinity thresholding. Our extension consists of two parts: First, we present a quasi-linear method to compute the loss gradient, improving over the original quadratic algorithm. Second, we compute the gradient in two separate passes to avoid spurious gradient contributions in early training stages. Our predictions are accurate enough that simple learning-free percentile-based agglomeration outperforms more involved methods used earlier on inferior predictions. We present results on three diverse EM datasets, achieving relative improvements over previous results of 27%, 15%, and 250%. Our findings suggest that a single method can be applied to both nearly isotropic block-face EM data and anisotropic serial sectioned EM data. The runtime of our method scales linearly with the size of the volume and achieves a throughput of about 2.6 seconds per megavoxel, qualifying our method for the processing of very large datasets

The Use of the "Preclosure” Technique for Antegrade Aspiration Thrombectomy with Large Catheters in Acute Limb Ischemia

Purpose: This study was designed to assess retrospectively short- and mid-term outcomes of the use of a suture-mediated closure device to close the antegrade access in patients undergoing percutaneous aspiration thrombectomy with large catheters for acute leg ischemia. Methods: Between November 2005 and February 2010, a suture-mediated active closure system (ProGlide® 6F, Abbott) was placed before arterial sheath (mean 9F, range 6-12F) introduction in 101 patients (74 men, 73%, mean age 70.1±12.6years standard deviation). Data regarding mortality, complications, and factors contributing to vascular complications at the access site was collected for 6month after the intervention to detect device-related problems. As a coincidence, 77 patients had follow-up visits for a duplex ultrasound. Results: There were a total of 19 vascular complications (19%) at the puncture site, all of which were of hemorrhagic nature and none of which consisted of vessel occlusion. Two major outcome complications (2%) occurred. A retroperitoneal hematoma and a serious inguinal bleeding required additive treatment and did not result in permanent sequelae. Nine cases involved death of which eight were not attributable to the closure and one remained unclear. Successful closure was achieved in 95 patients (94%); additional manual compression was sufficient in the majority of the remaining patients. Numerous factors contributing to vascular complications were encountered. Conclusions: With acceptable short- and mid-term outcomes, the "preclose” technique can be a reliable option for the closure of a large antegrade femoral access even for patients at a high risk of vascular complications, such as those undergoing aspiration thrombectom

The status quo of research on South Africa’s water resource management institutions

The South African water resource management institutional landscape has seen some dramatic changes since the new dispensation came into power in 1994. Not only have legislation and policies changed, but there has also been a significant increase in the number of non-state actors in the policy development process. Water resource governance has therefore become more complex and its regulatory component is being implemented by a number of legislative institutions: catchment management agencies, water user associations, irrigation boards, and international water management bodies. Policy development is influenced by a myriad of non-state actors, scientists included. A comprehensive literature review of research on water resource management institutions published between 1997 and 2011 shows that scientists are focusing predominantly on catchment management agencies and aspects regarding their institutionalisation and organisational functionality. There is much less of a focus on other entities, such as advisory committees, international water management bodies, irrigation boards, the water tribunal and water user associations. What the review has also revealed is that research on water resource management institutions has been conducted predominantly by scientists from the natural sciences. There is therefore an evident need for a research focus on water resource management institutions other than catchment management agencies. In addition, there should be a focus on informal aspects of water resource governance and new theoretical developments, also from disciplines other than the natural sciences, in the fields of water resource governance and politics.Keywords: Water resource management institutions, literature review, catchment management agencies,water user associations, legislation, irrigation boards, catchment forums, international water management bodie

Is there a "native" band gap in ion conducting glasses?

It is suggested that the spectrum of ion site energies in glasses exhibits a band gap, establishing an analogy between ion conducting glasses and intrinsic semiconductors. This implies that ion conduction in glasses takes place via vacancies and interstitial ions (as in crystals).Comment: 3 page

USA-CDAT Joint Statement of Facts

The United States\u27 and Coeur d\u27Alene Tribe\u27s Joint Statement of Fact

Nitrogen compounds and ozone in the stratosphere: comparison of MIPAS satellite data with the Chemistry Climate Model ECHAM5/MESSy1

International audienceThe chemistry climate model ECHAM5/MESSy1 (E5/M1) in a setup extending from the surface to 80 km with a vertical resolution of about 600 m near the tropopause with nudged tropospheric meteorology allows a direct comparison with satellite data of chemical species at the same time and location. Here we present results out of a transient 10 years simulation for the period of the Antarctic vortex split in September 2002, where data of MIPAS on the ENVISAT-satellite are available. For the first time this satellite instrument opens the opportunity, to evaluate all stratospheric nitrogen containing species simultaneously with a good global coverage, including the source gas N2O which allows an estimate for NOx-production in the stratosphere. We show correlations between simulated and observed species in the altitude region between 10 and 50 hpa for different latitude belts, together with the Probability Density Functions (PDFs) of model results and observations. This is supplemented by global charts on pressure levels showing the satellite data and the simulated data sampled at the same time and location. We demonstrate that the model in most cases captures the partitioning in the nitrogen family, the diurnal cycles and the spatial distribution within experimental uncertainty. There appears to be, however, a problem to reproduce the observed nighttime partitioning between N2O5 and NO2 in the middle stratosphere

USA-CDAT Joint Statement of Facts

The United States\u27 and Coeur d\u27Alene Tribe\u27s Joint Statement of Fact