85 research outputs found
Foreign Competition in Relevant Geographic Markets: Antitrust Law in World Markets
Since competition for the sale of many goods and services in the United States has foreign as well as domestic sources, the antitrust laws, designed to protect competition in the United States, must consider foreign competition. One important aspect of antitrust law that must include foreign competition is the relevant geographic market used to define the area in which effects on competition must be examined. As foreign competition exerts a greater influence on domestic competition, the United States antitrust laws, designed to protect competition in the United States and in the foreign commerce of the United States, must reflect the international scope of markets. In particular, the delineation of the relevant geographic market, used to define the area of competition in which to examine allegedly anticompetitive acts for violations of the antitrust laws, must extend beyond the United States to incorporate foreign competition that exerts a competitive influence in the United States
Foreign Competition in Relevant Geographic Markets: Antitrust Law in World Markets
Since competition for the sale of many goods and services in the United States has foreign as well as domestic sources, the antitrust laws, designed to protect competition in the United States, must consider foreign competition. One important aspect of antitrust law that must include foreign competition is the relevant geographic market used to define the area in which effects on competition must be examined. As foreign competition exerts a greater influence on domestic competition, the United States antitrust laws, designed to protect competition in the United States and in the foreign commerce of the United States, must reflect the international scope of markets. In particular, the delineation of the relevant geographic market, used to define the area of competition in which to examine allegedly anticompetitive acts for violations of the antitrust laws, must extend beyond the United States to incorporate foreign competition that exerts a competitive influence in the United States
Being Even Slightly Shallow Makes Life Hard
We study the computational complexity of identifying dense substructures, namely r/2-shallow topological minors and r-subdivisions. Of particular interest is the case r = 1, when these substructures correspond to very localized relaxations of subgraphs. Since Densest Subgraph can be solved in polynomial time, we ask whether these slight relaxations also admit efficient algorithms.
In the following, we provide a negative answer: Dense r/2-Shallow Topological Minor and Dense r-Subdivsion are already NP-hard for r = 1 in very sparse graphs. Further, they do not admit algorithms with running time 2^(o(tw^2)) n^O(1) when parameterized by the treewidth of the input graph for r > 2 unless ETH fails
Beveled Projectile Points and Ballistics Technology
Explanations for beveled blade edges on projectile points have been debated in North America archaeology since the first systematic description of lithic assemblages in the nineteenth century. Debate has centered around two opposing perspectives. One views beveled edges as features of projectile points that cause them to spin during flight. The other views beveling as a product of edge resharpening that is done unifacially to conserve scarce resources. Here we use a fluid-dynamics model to simulate the effect beveling has on projectiles. Expectations derived from this modeling are evaluated using wind-tunnel experiments. Our findings indicate that beveling produces in-flight rotation that serves as a means of increasing accuracy in relatively low-velocity flight paths.
Mucosal infection rewires TNFÉ‘ signaling dynamics to skew susceptibility to recurrence
A mucosal infectious disease episode can render the host either more or less susceptible to recurrent infection, but the specific mechanisms that tip the balance remain unclear. We investigated this question in a mouse model of recurrent urinary tract infection and found that a prior bladder infection resulted in an earlier onset of tumor necrosis factor-alpha (TNFÉ‘)-mediated bladder inflammation upon subsequent bacterial challenge, relative to age-matched naive mice. However, the duration of TNFÉ‘ signaling activation differed according to whether the first infection was chronic (Sensitized) or self-limiting (Resolved). TNFÉ‘ depletion studies revealed that transient early-phase TNFÉ‘ signaling in Resolved mice promoted clearance of bladder-colonizing bacteria via rapid recruitment of neutrophils and subsequent exfoliation of infected bladder cells. In contrast, sustained TNFÉ‘ signaling in Sensitized mice prolonged damaging inflammation, worsening infection. This work reveals how TNFÉ‘ signaling dynamics can be rewired by a prior infection to shape diverse susceptibilities to future mucosal infections
Association of DC-SIGN Promoter Polymorphism with Increased Risk for Parenteral, but Not Mucosal, Acquisition of Human Immunodeficiency Virus Type 1 Infection
There is considerable debate about the fundamental mechanisms that underlie and restrict acquisition of human immunodeficiency virus type 1 (HIV-1) infection. In light of recent studies demonstrating the ability of C type lectins to facilitate infection with HIV-1, we explored the potential relationship between polymorphisms in the DC-SIGN promoter and risk for acquisition of HIV-1 according to route of infection. Using samples obtained from 1,611 European-American participants at risk for parenteral (n = 713) or mucosal (n = 898) infection, we identified single-nucleotide polymorphisms in the DC-SIGN promoter using single-strand conformation polymorphism. Individuals at risk for parenterally acquired infection who had −336C were more susceptible to infection than were persons with −336T (odds ratio = 1.87, P = 0.001). This association was not observed in those at risk for mucosally acquired infection. A potential role for DC-SIGN specific to systemic acquisition and dissemination of infection is suggested
Lower Rotational Inertia and Larger Leg Muscles Indicate More Rapid Turns in Tyrannosaurids Than in Other Large Theropods
Synopsis: Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods.
Methods: To compare turning capability in theropods, we regressed agility estimates against body mass, incorporating superellipse-based modeled mass, centers of mass, and rotational inertia (mass moment of inertia). Muscle force relative to body mass is a direct correlate of agility in humans, and torque gives potential angular acceleration. Agility scores therefore include rotational inertia values divided by proxies for (1) muscle force (ilium area and estimates of m. caudofemoralis longus cross-section), and (2) musculoskeletal torque. Phylogenetic ANCOVA (phylANCOVA) allow assessment of differences in agility between tyrannosaurids and non-tyrannosaurid theropods (accounting for both ontogeny and phylogeny). We applied conditional error probabilities a(p) to stringently test the null hypothesis of equal agility.
Results: Tyrannosaurids consistently have agility index magnitudes twice those of allosauroids and some other theropods of equivalent mass, turning the body with both legs planted or pivoting over a stance leg. PhylANCOVA demonstrates definitively greater agilities in tyrannosaurids, and phylogeny explains nearly all covariance. Mass property results are consistent with those of other studies based on skeletal mounts, and between different figure-based methods (our main mathematical slicing procedures, lofted 3D computer models, and simplified graphical double integration).
Implications: The capacity for relatively rapid turns in tyrannosaurids is ecologically intriguing in light of their monopolization of large (\u3e400 kg), toothed dinosaurian predator niches in their habitats
Investigating the Potential and Pitfalls of EV-Encapsulated MicroRNAs as Circulating Biomarkers of Breast Cancer
Extracellular vesicles (EVs) shuttle microRNA (miRNA) throughout the circulation and are believed to represent a fingerprint of the releasing cell. We isolated and characterized serum EVs of breast tumour-bearing animals, breast cancer (BC) patients, and healthy controls. EVs were characterized using transmission electron microscopy (TEM), protein quantification, western blotting, and nanoparticle tracking analysis (NTA). Absolute quantitative (AQ)-PCR was employed to analyse EV-miR-451a expression. Isolated EVs had the appropriate morphology and size. Patient sera contained significantly more EVs than did healthy controls. In tumour-bearing animals, a correlation between serum EV number and tumour burden was observed. There was no significant relationship between EV protein yield and EV quantity determined by NTA, highlighting the requirement for direct quantification. Using AQ-PCR to relate miRNA copy number to EV yield, a significant increase in miRNA-451a copies/EV was detected in BC patient sera, suggesting potential as a novel biomarker of breast cancer
Radiation-free CMR diagnostic heart catheterization in children.
BACKGROUND: Children with heart disease may require repeated X-Ray cardiac catheterization procedures, are more radiosensitive, and more likely to survive to experience oncologic risks of medical radiation. Cardiovascular magnetic resonance (CMR) is radiation-free and offers information about structure, function, and perfusion but not hemodynamics. We intend to perform complete radiation-free diagnostic right heart catheterization entirely using CMR fluoroscopy guidance in an unselected cohort of pediatric patients; we report the feasibility and safety.
METHODS: We performed 50 CMR fluoroscopy guided comprehensive transfemoral right heart catheterizations in 39 pediatric (12.7 ± 4.7 years) subjects referred for clinically indicated cardiac catheterization. CMR guided catheterizations were assessed by completion (success/failure), procedure time, and safety events (catheterization, anesthesia). Pre and post CMR body temperature was recorded. Concurrent invasive hemodynamic and diagnostic CMR data were collected.
RESULTS: During a twenty-two month period (3/2015 - 12/2016), enrolled subjects had the following clinical indications: post-heart transplant 33%, shunt 28%, pulmonary hypertension 18%, cardiomyopathy 15%, valvular heart disease 3%, and other 3%. Radiation-free CMR guided right heart catheterization attempts were all successful using passive catheters. In two subjects with septal defects, right and left heart catheterization were performed. There were no complications. One subject had six such procedures. Most subjects (51%) had undergone multiple (5.5 ± 5) previous X-Ray cardiac catheterizations. Retained thoracic surgical or transcatheter implants (36%) did not preclude successful CMR fluoroscopy heart catheterization. During the procedure, two subjects were receiving vasopressor infusions at baseline because of poor cardiac function, and in ten procedures, multiple hemodynamic conditions were tested.
CONCLUSIONS: Comprehensive CMR fluoroscopy guided right heart catheterization was feasible and safe in this small cohort of pediatric subjects. This includes subjects with previous metallic implants, those requiring continuous vasopressor medication infusions, and those requiring pharmacologic provocation. Children requiring multiple, serial X-Ray cardiac catheterizations may benefit most from radiation sparing. This is a step toward wholly CMR guided diagnostic (right and left heart) cardiac catheterization and future CMR guided cardiac intervention.
TRIAL REGISTRATION: ClinicalTrials.gov NCT02739087 registered February 17, 2016
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