Development and testing of an algorithm for calculating the load on support of mine workings

Purpose. The purpose is to develop the calculation methods for minimizing the load on the fastening system of the preparatory mine working in difficult mining and geological conditions of its maintenance. Methods. By analysing the multivariate computational experiments on the study of the stress-strain state of the load-bearing elements of the “massif – support” system in the preparatory mine workings by means of the finite-element method, as well as mine observations and measurements of displacement in the coal-overlaying rock formation. Findings. An algorithm has been developed for searching the rational modes of the fastening system resistance and methods for minimizing the load on the support of the preparatory mine working, maintained in very complex mining and geological conditions. Originality. The methodical principles have been developed of minimizing the load on the fastening system of the preparatory mine working, which are based on the use of a combination of stress-strain state studies of the “massif – support” system by means of the finite element method and provisions of normative documents for calculating the dimensions of the dome of natural equilibrium of the mine working roof rocks. Practical implications. The operation modes optimisation of the load-bearing elements interaction of the mine working fastening system reduces the material and labour costs during its construction and increases its stability during operation.Мета. Розробити методику розрахунку мінімізації навантаження на кріпильну систему підготовчої виробки у складних гірничо-геологічних умовах її підтримки. Методика. Аналіз різноманітних обчислювальних експериментів з дослідження напружено-деформованого стану вантажонесучих елементів системи “масив – кріплення” підготовчих виробок методом скінченних елементів, а також шахтних спостережень і вимірювань зрушення надвугільної товщі порід. Результати. Розроблено алгоритм пошуку раціональних режимів опору кріплення системи і методику мінімізації навантаження на кріплення підготовчої виробки, яка підтримується у досить складних гірничо-геологічних умовах. Наукова новизна. Розроблено методичні засади мінімізації навантаження на кріпильну систему підготовчої виробки, що побудовані на використанні комбінації досліджень напружено-деформованого стану системи “масив – кріплення” за допомогою методу скінченних елементів і положень нормативних документів з розрахунку розмірів склепіння природної рівноваги порід покрівлі виробки. Практична значимість. Оптимізація робочих режимів взаємодії вантажонесучих елементів кріплення системи виробки знижує матеріальні й трудові витрати при її спорудженні та підвищує стійкість при експлуатації.Цель. Разработать методику расчета минимизации нагрузки на крепежную систему подготовительной выработки в сложных горно-геологических условиях ее поддержания. Методика. Анализ многовариантных вычислительных экспериментов по исследованию напряженно-деформированного состояния грузонесущих элементов системы “массив – крепь” подготовительных выработок методом конечных элементов, а также шахтных наблюдений и измерений сдвижения надугольной толщи пород. Результаты. Разработан алгоритм поиска рациональных режимов сопротивления крепежной системы и методика минимизации нагрузки на крепь подготовительной выработки, поддерживаемой в весьма сложных горно-геологических условиях. Научная новизна. Разработаны методические принципы минимизации нагрузки на крепежную систему подготовительной вы-работки, построенные на использовании комбинации исследований напряженно-деформированного состояния системы “массив – крепь” с помощью метода конечных элементов и положений нормативных документов по расчету размеров свода естественного равновесия пород кровли выработки. Практическая значимость. Оптимизация рабочих режимов взаимодействия грузонесущих элементов крепежной системы вы-работки снижает материальные и трудовые затраты при ее сооружении и повышает устойчивость при эксплуатации.The authors express their gratitude to the management of DTEK Coal Unit for their help in organizing the experimental research

Momentum Entanglement for Atom Interferometry

Compared to light interferometers, the flux in cold-atom interferometers is low and the associated shot noise is large. Sensitivities beyond these limitations require the preparation of entangled atoms in different momentum modes. Here, we demonstrate a source of entangled atoms that is compatible with state-of-the-art interferometers. Entanglement is transferred from the spin degree of freedom of a Bose-Einstein condensate to well-separated momentum modes, witnessed by a squeezing parameter of -3.1 (8) dB. Entanglement-enhanced atom interferometers promise unprecedented sensitivities for quantum gradiometers or gravitational wave detectors

Overall survival results from the randomized phase 2 study of palbociclib in combination with letrozole versus letrozole alone for first‑line treatment of ER+/HER2− advanced breast cancer (PALOMA‑1, TRIO‑18)

Purpose Palbociclib is a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, approved in combination with endocrine therapy for the treatment of women and men with hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer (HR+/HER2− ABC). In the phase 2, open-label, PALOMA-1 trial, palbociclib plus letrozole signifcantly prolonged progression-free survival (PFS) versus letrozole alone (hazard ratio, 0.488; 95% CI 0.319‒0.748; P=0.0004; median PFS, 20.2 vs 10.2 months, respectively) in postmenopausal women with estrogen receptor–positive (ER+)/HER2− ABC. Here, we present the fnal overall survival (OS) and updated safety results. Methods Postmenopausal women with ER+/HER2− ABC were randomized 1:1 to receive either palbociclib (125 mg/day, 3/1 schedule) plus letrozole (2.5 mg/day, continuous) or letrozole alone (2.5 mg/day, continuous). The primary endpoint was investigator-assessed PFS; secondary endpoints included OS and safety. Results A total of 165 patients were randomized. At the data cutof date of December 30, 2016 (median duration of follow-up, 64.7 months), the stratifed hazard ratio for OS was 0.897 (95% CI 0.623–1.294; P=0.281); median OS in the palbociclib plus letrozole and letrozole alone arms was 37.5 and 34.5 months, respectively. The median time from randomization to frst subsequent chemotherapy use was longer with palbociclib plus letrozole than letrozole alone (26.7 and 17.7 months, respectively). The most frequently reported adverse event in the palbociclib plus letrozole arm was neutropenia (any grade, 75%; grade 3 or 4, 59%). Conclusions Palbociclib plus letrozole treatment led to a numerical but not statistically signifcant improvement in median OS. Pfzer Inc (NCT00721409

Efficacy and safety of palbociclib in combination with letrozole as first-line treatment of ER-positive, HER2-negative, advanced breast cancer: expanded analyses of subgroups from the randomized pivotal trial PALOMA-1/TRIO-18

Background: Palbociclib is an oral small-molecule inhibitor of cyclin-dependent kinases 4 and 6. In the randomized, open-label, phase II PALOMA-1/TRIO-18 trial, palbociclib in combination with letrozole improved progression-free survival (PFS) compared with letrozole alone as first-line treatment of estrogen receptor (ER) -positive, human epidermal growth factor receptor 2 (HER2)-negative, advanced breast cancer (20.2 months versus 10.2 months; hazard ratio (HR) = 0.488, 95 % confidence interval (CI) 0.319–0.748; one-sided p = 0.0004). Grade 3–4 neutropenia was the most common adverse event (AE) in the palbociclib + letrozole arm. We now present efficacy and safety analyses based on several specific patient and tumor characteristics, and present in detail the clinical patterns of neutropenia observed in the palbociclib + letrozole arm of the overall safety population. Methods: Postmenopausal women (n = 165) with ER+, HER2-negative, advanced breast cancer who had not received any systemic treatment for their advanced disease were randomized 1:1 to receive either palbociclib in combination with letrozole or letrozole alone. Treatment continued until disease progression, unacceptable toxicity, consent withdrawal, or death. The primary endpoint was PFS. We now analyze the difference in PFS for the treatment populations by subgroups, including age, histological type, history of prior neoadjuvant/adjuvant systemic treatment, and sites of distant metastasis, using the Kaplan-Meier method. HR and 95 % CI are derived from a Cox proportional hazards regression model. Results: A clinically meaningful improvement in median PFS and clinical benefit response (CBR) rate was seen with palbociclib + letrozole in every subgroup evaluated. Grade 3–4 neutropenia was the most common AE with palbociclib + letrozole in all subgroups. Analysis of the frequency of neutropenia by grade during the first six cycles of treatment showed that there was a downward trend in Grade 3–4 neutropenia over time. Among those who experienced Grade 3–4 neutropenia, 71.7 % had no overlapping infections of any grade and none had overlapping Grade 3–4 infections. Conclusion: The magnitude of clinical benefit seen with the addition of palbociclib to letrozole in improving both median PFS and CBR rate is consistent in nearly all subgroups analyzed, and consistent with that seen in the overall study population. The safety profile of the combination treatment in all subgroups was also comparable to that in the overall safety population of the study. Abbreviations: AE, adverse event; CBR, clinical benefit response; CDK, cyclin-dependent kinase; CI, confidence interval; ECOG, Eastern Cooperative Oncology Group; ER, estrogen receptor; FISH, fluorescent in-situ hybridization; HER2, human epidermal growth factor receptor 2; HR, hazard ratio; HR+, hormone receptor-positive; ITT, intention-to-treat; PFS, progression-free survival; RECIST, Response Evaluation Criteria in Solid Tumors

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011