Supercooperation in Evolutionary Games on Correlated Weighted Networks

In this work we study the behavior of classical two-person, two-strategies evolutionary games on a class of weighted networks derived from Barab\'asi-Albert and random scale-free unweighted graphs. Using customary imitative dynamics, our numerical simulation results show that the presence of link weights that are correlated in a particular manner with the degree of the link endpoints, leads to unprecedented levels of cooperation in the whole games' phase space, well above those found for the corresponding unweighted complex networks. We provide intuitive explanations for this favorable behavior by transforming the weighted networks into unweighted ones with particular topological properties. The resulting structures help to understand why cooperation can thrive and also give ideas as to how such supercooperative networks might be built.Comment: 21 page

Inter-Rater Reliability Of Physical Abuse Determinations And Abusive Fracture Incidence At A Level 1 Pediatric Trauma Center

As there is no “gold standard” in determining whether a fracture is caused by accident or abuse, agreement among medical providers is paramount. Using abstracted medical record data from children \u3c36 months of age presenting to a level 1 pediatric emergency department (ED), we examined the extent of agreement between specialists who evaluate children with fractures for suspected abuse. To simulate clinical scenarios, two pediatric orthopaedists and two child abuse pediatricians (CAPs) reviewed the full abstraction and imaging, whereas the two pediatric radiologists reviewed a brief history and imaging. Each physician independently rated each case using a 7-point ordinal scale designed to distinguish accidental from abusive injuries. For any discrepancy in independent ratings, the two specialists discussed the case and came to a joint rating. We analyzed 3 types of agreement: (1) within specialties using independent ratings, (2) between specialties using joint ratings, and (3) between clinicians (orthopaedists and CAPs) with more versus less experience. Agreement between pairs of raters was assessed using Cohen’s weighted kappa. From 2007 to 2010, 551 children presented to the Yale New Haven Children’s Hospital Pediatric ED with 572 fractures. Twenty-eight cases (5.1%) were determined to have fractures with a consensus rating indicating abuse. The skull was the most commonly fractured bone and rib fractures had the highest association with an abuse consensus rating (86.7%). The incidence of children presenting with an abusive fracture in the county per year was 2.4 per 10,000 children \u3c36 months of age. The incidence of children presenting with an abusive fracture per ED visit was 2.2 per 10,000 visits. Orthopaedists (κ=.78) and CAPs (κ=.67) had substantial within-specialty agreement, while radiologists (κ=.53) had moderate agreement. Orthopaedists and CAPs had almost perfect between-specialty agreement (κ=.81), while agreement was much lower for orthopaedists and radiologists (κ=.37) and CAPs and radiologists (κ=.42). More-experienced clinicians had substantial between-specialty agreement (κ=.80) versus less-experienced clinicians who had moderate agreement (κ=.60). These findings suggest the level of clinical detail a physician receives and his/her experience in the field has an impact on the level of agreement when evaluating fractures in young children. The lack of clinical data provided to the radiologists limited their ability to designate a fracture as definitively abusive or accidental, likely lowering observed agreement scores

Chrysaora quinquecirrha Polyps in Barnegat Bay, NJ

Sea nettles (Chrysaora quinquecirrha) have become abundant in the estuaries of the Mid- Atlantic States. Their ample numbers are an indicator of a disturbed ecosystem. Various factors have been attributed to the rise in numbers of sea nettles including eutrophication, overfishing, global warming, construction and species introduction. Bamegat Bay is a highly eutrophic system with excess nitrogen and organic carbon arriving in the bay via runoff and watershed waste inputs. Many commercial fisheries in Bamegat Bay have ceased to exist and the remaining fisheries are dwindling. An overabundance of medusae and polyps will further impact fisheries since jellyfish compete with larval fish when young and prey on planktonic eggs and larvae as they mature. While observations of the medusa stage indicate a disproportionate abundance in the northern part of the bay, quantification of these differences has not taken place. Information about the life history of the Chrysaora quinquecirrha polyp in the field is limited. This research focused on undertaking a settlement survey of polyps from eight sites in Bamegat Bay. Results showed initial settlement in July with continued settlement observed until November. Of the eight sites monitored monthly, only two sites showed settlement and both of these occurred in the northern portion of the bay. Peak settlement was seen at Cattus Island during August with 1,528 polyps collected from that settling plate. Water quality assessment indicated that these sites had lower salinities than all of the other sites except Toms River. Previous research in the Chesapeake Bay has established that Chrysaora quinquecirrha polyps are only found in waters of 5-20ppt salinity. Polyp growth and strobilation will directly determine adult medusa populations. Therefore, the distributions of polyps and medusae are most likely linked and reflect differences in water quality. Other factors may also influence polyp populations including the other species found on the plates with the polyps. With continued research, a count of polyps could be used to predict future medusae populations. This study reports on the temporal and spatial patterns of polyp distribution in Bamegat Bay and the differences in physical characteristics and species composition at the sites where polyps were located

Generating Robust and Efficient Networks Under Targeted Attacks

Much of our commerce and traveling depend on the efficient operation of large scale networks. Some of those, such as electric power grids, transportation systems, communication networks, and others, must maintain their efficiency even after several failures, or malicious attacks. We outline a procedure that modifies any given network to enhance its robustness, defined as the size of its largest connected component after a succession of attacks, whilst keeping a high efficiency, described in terms of the shortest paths among nodes. We also show that this generated set of networks is very similar to networks optimized for robustness in several aspects such as high assortativity and the presence of an onion-like structure

Boundary Adversarial Examples Against Adversarial Overfitting

Standard adversarial training approaches suffer from robust overfitting where the robust accuracy decreases when models are adversarially trained for too long. The origin of this problem is still unclear and conflicting explanations have been reported, i.e., memorization effects induced by large loss data or because of small loss data and growing differences in loss distribution of training samples as the adversarial training progresses. Consequently, several mitigation approaches including early stopping, temporal ensembling and weight perturbations on small loss data have been proposed to mitigate the effect of robust overfitting. However, a side effect of these strategies is a larger reduction in clean accuracy compared to standard adversarial training. In this paper, we investigate if these mitigation approaches are complimentary to each other in improving adversarial training performance. We further propose the use of helper adversarial examples that can be obtained with minimal cost in the adversarial example generation, and show how they increase the clean accuracy in the existing approaches without compromising the robust accuracy

Utah Girls, Young Women, and Physical Activity

The benefits of physical activity are well documented and improve all aspects of health and overall wellbeing. Globally, on average, 37.1% of women are insufficiently physically active while only 23.4% of men are; this trend is also found in Utah, where 19.4% of women are insufficiently physically active while only 17.6% of men are. While women often live longer than men, they are frequently in worse health. Physical inactivity contributes to the development and severity of chronic diseases including cardiovascular disease, diabetes, and hypertension. In addition to affecting physical health, physical inactivity is also associated with poor mental health. Physical activity can contribute to positive self-image and improved confidence, which is critical for meaningful community participation as well as developing interpersonal relationships

Tracking and Vertexing with a Thin CMOS Pixel Beam Telescope

We present results of a study of charged particle track and vertex reconstruction with a beam telescope made of four layers of 50 micron-thin CMOS monolithic pixel sensors using the 120 GeV protons at the FNAL Meson Test Beam Facility. We compare our results to the performance requirements of a future e+e- linear collider in terms of particle track extrapolation and vertex reconstruction accuracies.Comment: 9 pages, 7 figures submitted to Nuclear Instruments and Methods