The biker-glove pattern of congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are common birthmarks with 20% occurring on the limbs. We describe 4 patients with acral CMN with a “biker‐glove” distribution with sparing of the distal digits, as has previously been described in acral infantile hemangiomas (IH). The existence of the biker‐glove pattern suggests that CMN arise from early mutations in melanocyte precursors and supports the recently described Kinsler‐Larue hypothesis of mesenchymal distribution of melanocyte migration occurring in a circular field from a central point. Developmental errors in mesenchymal precursors with similar migration patterns may explain this shared pattern among CMN and IH

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Measurement of the cross-section for b-jets produced in association with a Z boson at root s=7 TeV with the ATLAS detector ATLAS Collaboration

A measurement is presented of the inclusive cross-section for b-jet production in association with a Z boson in pp collisions at a centre-of-mass energy of root s = 7 TeV. The analysis uses the data sample collected by the ATLAS experiment in 2010, corresponding to an integrated luminosity of approximately 36 pb(-1). The event selection requires a Z boson decaying into high P-T electrons or muons, and at least one b-jet, identified by its displaced vertex, with transverse momentum p(T) > 25 GeV and rapidity vertical bar y vertical bar < 2.1. After subtraction of background processes, the yield is extracted from the vertex mass distribution of the candidate b-jets. The ratio of this cross-section to the inclusive Z cross-section (the average number of b-jets per Z event) is also measured. Both results are found to be in good agreement with perturbative QCD predictions at next-to-leading order

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Infantile hemangiomas: from pathogenesis to clinical features

Adena Rosenblatt,1 Erin F Mathes,2 Kristina W Rosbe31Department of Pediatrics, University of California, San Francisco, 2Division of Pediatric Dermatology, Departments of Dermatology and Pediatrics, University of California, San Francisco, 3Division of Pediatric Otolaryngology, Department of Otolaryngology &amp;ndash; Head and Neck Surgery, University of California, San Francisco, CA, USAAbstract: Infantile hemangiomas (IH) are benign vascular tumors consisting of a collection of immature cells, including progenitor stem cells and disorganized blood vessels. They are the most common benign tumors in childhood. Recently, there have been significant, exciting advancements in the understanding of the pathogenesis and treatment of infantile hemangiomas, which are discussed in this review. The decision to initiate treatment for IH is based on many factors, including size and location, functional compromise, psychosocial implications, and risks and benefits of the proposed therapy. For most families of children with hemangiomas, education about the natural history of IH and reassurance are often the only &amp;quot;treatment&amp;quot; required. A minority of patients with large, complex lesions or lesions that cause functional compromise require early intervention. These patients and families benefit from a multidisciplinary approach to care in vascular birthmark centers. Ongoing multi-institutional clinical trials will provide further important data on the efficacy and safety of hemangioma treatments.Keywords: progenitor stem cell, glucose transporter 1, PHACES, LUMBAR, infantile hemangiom

MRI phenotypes of localized intravascular coagulopathy in venous malformations

Background: The incidence of localized intravascular coagulopathy (LIC) in venous malformations varies with lesion size and location, as well as the presence of palpable phleboliths. The development of LIC can cause pain and hemorrhage and can progress to disseminated intravascular coagulopathy (DIC) and thromboembolic disease resulting in death in some cases. Early recognition of LIC can relieve symptoms and prevent progression to life-threatening complications. Objective: The aim of this work was to identify MRI features of venous malformation associated with LIC. We hypothesized that venous malformations with larger capacitance, slower flow and less physiological compression (greater stasis) were more likely to be associated with LIC. Materials and methods: In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed clinical records and MRI for consecutive patients undergoing evaluation of venous malformations at our multidisciplinary Birthmarks and Vascular Anomalies Center between 2003 and 2013. Inclusion required consensus diagnosis of venous malformation and availability of laboratory data and MRI; patients on anticoagulation or those previously undergoing surgical or endovascular treatment were excluded. LIC was diagnosed when D-dimer exceeded 1,000&nbsp;ng/mL and/or fibrinogen was less than 200&nbsp;mg/dL. Two board-certified radiologists assessed the following MRI features for each lesion: morphology (spongiform vs. phlebectatic), presence of phleboliths, size, location (truncal vs. extremity), and tissue type(s) involved (subcutis, muscle, bone and viscera). Univariate logistic regression analyses were used to test associations between LIC and MRI findings, and stepwise regression was applied to assess the significance of the individual imaging predictors. Results: Seventy patients, 37 with LIC, met inclusion criteria during the 10-year study period (age: 14.5 +/- 13.6 years [mean +/- standard deviation]; 30 male, 40 female). Both elevated D-dimer and low fibrinogen were associated with the presence of phleboliths, larger lesion sizes and visceral involvement on MRI (all P &lt; 0.05). In stepwise regressions, lesion size (P &lt; 0.001), the presence of phleboliths (P = 0.005) and lesion morphology (P = 0.006) were all significant predictors of LIC. Conclusion: LIC is associated with larger lesion size, visualized phleboliths, truncal location and spongiform morphology on MRI in venous malformations, suggesting that lesions with larger capacitance, slower flow and less physiological compression are more likely to be associated with coagulopathy

MRI phenotypes of localized intravascular coagulopathy in venous malformations

Background: The incidence of localized intravascular coagulopathy (LIC) in venous malformations varies with lesion size and location, as well as the presence of palpable phleboliths. The development of LIC can cause pain and hemorrhage and can progress to disseminated intravascular coagulopathy (DIC) and thromboembolic disease resulting in death in some cases. Early recognition of LIC can relieve symptoms and prevent progression to life-threatening complications. Objective: The aim of this work was to identify MRI features of venous malformation associated with LIC. We hypothesized that venous malformations with larger capacitance, slower flow and less physiological compression (greater stasis) were more likely to be associated with LIC. Materials and methods: In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed clinical records and MRI for consecutive patients undergoing evaluation of venous malformations at our multidisciplinary Birthmarks and Vascular Anomalies Center between 2003 and 2013. Inclusion required consensus diagnosis of venous malformation and availability of laboratory data and MRI; patients on anticoagulation or those previously undergoing surgical or endovascular treatment were excluded. LIC was diagnosed when D-dimer exceeded 1,000&nbsp;ng/mL and/or fibrinogen was less than 200&nbsp;mg/dL. Two board-certified radiologists assessed the following MRI features for each lesion: morphology (spongiform vs. phlebectatic), presence of phleboliths, size, location (truncal vs. extremity), and tissue type(s) involved (subcutis, muscle, bone and viscera). Univariate logistic regression analyses were used to test associations between LIC and MRI findings, and stepwise regression was applied to assess the significance of the individual imaging predictors. Results: Seventy patients, 37 with LIC, met inclusion criteria during the 10-year study period (age: 14.5 +/- 13.6 years [mean +/- standard deviation]; 30 male, 40 female). Both elevated D-dimer and low fibrinogen were associated with the presence of phleboliths, larger lesion sizes and visceral involvement on MRI (all P &lt; 0.05). In stepwise regressions, lesion size (P &lt; 0.001), the presence of phleboliths (P = 0.005) and lesion morphology (P = 0.006) were all significant predictors of LIC. Conclusion: LIC is associated with larger lesion size, visualized phleboliths, truncal location and spongiform morphology on MRI in venous malformations, suggesting that lesions with larger capacitance, slower flow and less physiological compression are more likely to be associated with coagulopathy