Bounding the Porous Exponential Domination Number of Apollonian Networks

Given a graph G with vertex set V, a subset S of V is a dominating set if every vertex in V is either in S or adjacent to some vertex in S. The size of a smallest dominating set is called the domination number of G. We study a variant of domination called porous exponential domination in which each vertex v of V is assigned a weight by each vertex s of S that decreases exponentially as the distance between v and s increases. S is a porous exponential dominating set for G if all vertices in S distribute to vertices in G a total weight of at least 1. The porous exponential domination number of G is the size of a smallest porous exponential dominating set. In this paper we compute bounds for the porous exponential domination number of special graphs known as Apollonian networks.Comment: 8 pages, 5 figures, 1 table, Research partially funded by CURM, the Center for Undergraduate Research, and NSF grant DMS-114869

Anaplastic Thyroid Carcinoma Histologically Mimicking a Plasmacytoma.

Anaplastic (undifferentiated) thyroid carcinoma (ATC) is a rare malignancy which may arise from transformation of a pre-existing differentiated carcinoma. We report the unique case where a lesion of thyroid origin presented with the histological features of mature plasma cells. Immunohistochemistry confirmed the lesion to be an anaplastic thyroid carcinoma arising from papillary thyroid carcinoma. A tumor mimicking a malignancy of a different cellular origin can lead clinicians to incorrect treatment approaches. Careful correlation with clinical details and knowledge of these unique presentations is important for reaching the correct diagnosis

Runoff treatment with aspen wood

Runoff from roadways and urban areas is often contaminated with heavy metals such as zinc and copper. The use of aspen wood (Populus tremula) was investigated as a potential sorbentfor these metal contaminated runoff waters. The objective was to design an alternative runoff treatment technology based on a renewable resource, i.e. wood. Laboratory isotherms and column experiments were conducted in order to investigate the sorption and desorption of dissolved copper and zinc to and from aspen wood fibers. Sorption ofCu(II) and Zn(II) followed non-linear Freundlich isotherms. The aspen wood-water partition coefficient values revealed that Cu(II) had a greater tendency to sorb to the aspen wood than Zn(II). The column experiments indicated that, at least initially, both metals were being rapidly sorbed. During later stages of the sorption experiments, slower, but steady transport of the metal ions into the wood fibers appeared to be the dominating removal mechanism. Desorption of copper with E-pure water was faster than zinc, but the total amount of metal mass released from the wood was small in both cases, i.e., only 2% to 4% of the amount sorbed. Although initial dissolved metal removal data from an ongoing field test is inconclusive, it was shown that a proto-type wood filter and a viable runoff treatment technology can be build around wood-based filte

Lunar Environment Simulation for a High Performance Motor

NASA and the Canadian Space Agency (CSA) through a CSA contractor, Argo Space/Robotics Division, partnered to perform environmental performance tests on a high torque producing motor. CSA provided the motor and NASA provided a thermal vacuum chamber capable of achieving high vacuum (P < 1 E-5 torr) and temperatures between 25 and 400 K. NASA also provided a dynamometer system capable of measuring and or applying break torque between 0 and 28 Nm. The two primary goals of the test were to simulate sun exposed and shadow condition expected on the lunar surface in order to determine survivability of the motor at extreme temperature conditions and to operate the motor under a constant break load of 6.8 Nm in the temperature range of 30K to 415K. A secondary objective of the test was to operate the motor for 15 km under 6.8 Nm of load. The primary goals of the test were fully achieved. The secondary goal was partially achieved

Tracking Student Propositions in an Inquiry System

We built software to support student reasoning about a phenomenon and development of hypotheses to explain it. The goal is to engage students in asking questions, generating hypotheses and testing predictions. Rashi, an intelligent tutor, tracks students’ investigations (e.g., hypotheses, questions, data collection, and inferences) and helps articulate how evidence and theories are related. The tutor provides advice, such as recognizing when data does not support a hypothesis Cases are presented in geology, biology or engineering, and students are scaffolded to use an inquiry-based approach to posit a theory to explain the situation. Generic and reusable structured tools guide students through exploration of ill-structured problem spaces, supporting student knowledge and scaffolding reasoning and diagnostic skills

Management of blunt extracranial traumatic cerebrovascular injury: a multidisciplinary survey of current practice

<p>Abstract</p> <p>Background</p> <p>Extracranial traumatic cerebrovascular injury (TCVI) is present in 1-3% of all blunt force trauma patients. Although options for the management of patients with these lesions include anticoagulation, antiplatelet agents, and endovascular treatment, the optimal management strategy for patients with these lesions is not yet established.</p> <p>Objective</p> <p>Multidisciplinary survey of clinicians about current management of TCVI.</p> <p>Methods</p> <p>A six-item multiple-choice survey was sent by electronic mail to a total of 11,784 neurosurgeons, trauma surgeons, stroke neurologists, and interventional radiologists. The survey included questions about their choice of imaging, medical management, and the use of endovascular techniques. Survey responses were analyzed according to stated specialty.</p> <p>Results</p> <p>Seven hundred eighty-five (6.7%) responses were received. Overall, a total of 325 (42.8%) respondents favored anticoagulation (heparin and/or warfarin), 247 (32.5%) favored antiplatelet drugs, 130 (17.1%) preferred both anticoagulation and antiplatelet drugs, and 57 (7.5%) preferred stenting and/or embolization. Anticoagulation was the most commonly preferred treatment among vascular surgeons (56.9%), neurologists (50.2%) and neurosurgeons (40.7%), whereas antiplatelet agents were the most common preferred treatment among trauma surgeons (41.5%). Overall, 158 (20.7%) of respondents recommended treatment of asymptomatic dissections and traumatic aneurysms, 211 (27.7%) did not recommend it, and 39.4% recommended endovascular treatment only if there is worsening of the lesion on follow-up imaging.</p> <p>Conclusions</p> <p>These data demonstrate the wide variability of physicians' management of traumatic cerebrovascular injury, both on an individual basis, and between specialties. These findings underscore the need for multicenter, randomized trials in this field.</p

Network hygiene, incentives, and regulation: Deployment of source address validation in the internet

The Spoofer project has collected data on the deployment and characteristics of IP source address validation on the Internet since 2005. Data from the project comes from participants who install an active probing client that runs in the background. The client automatically runs tests both periodically and when it detects a new network attachment point. We analyze the rich dataset of Spoofer tests in multiple dimensions: across time, networks, autonomous systems, countries, and by Internet protocol version. In our data for the year ending August 2019, at least a quarter of tested ASes did not filter packets with spoofed source addresses leaving their networks. We show that routers performing Network Address Translation do not always filter spoofed packets, as 6.4% of IPv4/24 tested in the year ending August 2019 did not filter. Worse, at least two thirds of tested ASes did not filter packets entering their networks with source addresses claiming to be from within their network that arrived from outside their network. We explore several approaches to encouraging remediation and the challenges of evaluating their impact. While we have been able to remediate 352 IPv4/24, we have found an order of magnitude more IPv4/24 that remains unremediated, despite myriad remediation strategies, with 21% unremediated for more than six months. Our analysis provides the most complete and confident picture of the Internet's susceptibility to date of this long-standing vulnerability. Although there is no simple solution to address the remaining long-tail of unremediated networks, we conclude with a discussion of possible non-technical interventions, and demonstrate how the platform can support evaluation of the impact of such interventions over time

Biochemical and biophysical characterization of cell-free synthesized Rift Valley fever virus nucleoprotein capsids enables in vitro screening to identify novel antivirals

Cell fractionation indicates that the compounds access the nucleus. The most potent compounds were exposed to HEK cells at a concentration of 1 ΟM for 24 h, after which the nucleus was separated from the cytoplasm. The concentration of these two blue compounds could be observed by the relative higher intensity in the nucleus compared to that in the cytoplasm. (PDF 3721 kb

Modulation of receptor dynamics by the regulator of G protein signaling Sst2

G protein–coupled receptor (GPCR) signaling is fundamental to physiological processes such as vision, the immune response, and wound healing. In the budding yeast Saccharomyces cerevisiae, GPCRs detect and respond to gradients of pheromone during mating. After pheromone stimulation, the GPCR Ste2 is removed from the cell membrane, and new receptors are delivered to the growing edge. The regulator of G protein signaling (RGS) protein Sst2 acts by accelerating GTP hydrolysis and facilitating pathway desensitization. Sst2 is also known to interact with the receptor Ste2. Here we show that Sst2 is required for proper receptor recovery at the growing edge of pheromone-stimulated cells. Mathematical modeling suggested pheromone-induced synthesis of Sst2 together with its interaction with the receptor function to reestablish a receptor pool at the site of polarized growth. To validate the model, we used targeted genetic perturbations to selectively disrupt key properties of Sst2 and its induction by pheromone. Together our results reveal that a regulator of G protein signaling can also regulate the G protein–coupled receptor. Whereas Sst2 negatively regulates G protein signaling, it acts in a positive manner to promote receptor retention at the growing edge