Composite fermions traversing a potential barrier

Using a composite fermion picture, we study the lateral transport between two two-dimensional electron gases, at filling factor 1/2, separated by a potential barrier. In the mean field approximation, composite fermions far from the barrier do not feel a magnetic field while in the barrier region the effective magnetic field is different from zero. This produces a cutoff in the conductance when represented as a function of the thickness and height of the barrier. There is a range of barrier heights for which an incompressible liquid, at $\nu =1/3$, exists in the barrier region.Comment: 3 pages, latex, 4 figures available upon request from [email protected]. To appear in Physical Review B (RC) June 15t

UJI KONSENTRASI HAMBAT MINIMUM (KHM) EKSTRAK DAUN LEILEM (Clerodendrum minahassae L.) TERHADAP BAKTERI Streptococcus mutans

UJI KONSENTRASI HAMBAT MINIMUM (KHM) EKSTRAK DAUN LEILEM (Clerodendrum minahassae L.) TERHADAP BAKTERI Streptococcus mutans Hanna R. R. Situmorang1), Olivia Waworuntu1), Christy Mintjelungan1) 1) Program Studi Pendidikan Dokter Gigi Fakultas Kedokteran  UNSRAT Manado, 95115 ABSTRACT              Caries is one of the dental and oral diseases that are often experienced by the population of Indonesia. Caries is a disease of hard dental tissue , which consists of email , dentin and cementum , which is caused by the activity of microorganisms in fermentable carbohydrates. Streptococcus mutans bacteria are known to be the main cause of dental caries. Leilem leaf (Clerodendrum minahassae L.) is one of a herbal plant containing of antimicrobial compounds, namely flavonoid, fenol, steroid and terpenoid. A study has been held in Manado by Bontjura et al in 2015 proved that the extract of leilem leaf (Clerodendrum minahassae L.) could inhibit the Streptococcus mutans.The purpose of this study is to determine the minimal inhibitory concentration (MIC) of leilem leaf (Clerodendrum minahassae L.) to Streptococcus mutans. This research is a true experimental research with Randomized Pretest-Posttest Control Group Design. This method used in this study is serial dilution method with turbidimetry and spectrophotometry as the test methods. Leilem leaf was taken from Paniki, subdistrict of Mapanget, and was extracted with maceration method using ethanol 96%. Streptococcus mutans bacterial was taken from a pure bacterial stock in Pharmacy Laboratory Faculty of Mathematics and Natural Science University of Sam Ratulangi Manado.Based on this research the minimal inhibitory concentration (MIC) of leilem leaf extract (Clerodendrum minahassae L.) to Streptococcus mutans is in the concentration of 12,5%. Keywords : leilem leaf (Clerodendrum minahassae L.), Streptococcus mutans, minimal inhibitory concentration (MIC), caries. ABSTRAK Karies merupakan salah satu penyakit gigi dan mulut yang sering dialami oleh penduduk Indonesia. Karies adalah suatu penyakit jaringan keras gigi, yaitu email, dentin dan sementum, yang disebabkan oleh aktivitas suatu jasad renik dalam suatu karbohidrat yang dapat diragikan. Streptococcus mutans diketahui merupakan bakteri penyebab utama timbulnya karies gigi. Ekstrak daun leilem (Clerodendrum minahassae L.) merupakan salah satu tanaman herbal yang mengandung senyawa antibakteri,  yaitu flavonoid, fenol, steroid, dan terpenoid. Sebuah penelitian yang telah dilakukan oleh Bontjura dkk pada tahun 2015 di Manado membuktikan bahwa ekstrak daun leilem (Clerodendrum minahassae L.) dapat menghambat bakteri Streptococcus mutans. Tujuan penelitian ini adalah untuk mengetahui konsentrasi hambat minimum (KHM) ekstrak daun leilem (Clerodendrum minahassae L.) terhadap bakteri Streptococcus mutans. Penelitian ini merupakan penelitian Randomized Pretest-Posstest Control Group Design. Metode yang digunakan dalam penelitian ini yaitu metode serial dilusi dengan metode pengujian turbidimetri dan spektrofotometri. Daun leilem diperoldeh di daerah Paniki, Kecamatan Mapanget, dan diekstraksi dengan metode maserasi menggunakan pelarut etanol 96%. Bakteri Streptococcus mutans diambil dari stok bakteri murni Laboratorium Farmasi Fakultas MIPA Universitas Sam Ratulangi Manado. Berdasarkan penelitian ini dapat disimpulkan bahwa konsentrasi hambat minimum (KHM) ekstrak daun leilem (Clerodendrum minahassae L.) terhadap bakteri Streptococcus mutans yaitu pada konsentrasi 12,5%.   Kata kunci : daun leilem (Clerodendrum minahassae L.), Streptococcus mutans, konsentrasi hambat minimum (KHM), karie

Persistent Spin Currents in Helimagnets

We demonstrate that weak external magnetic fields generate dissipationless spin currents in the ground state of systems with spiral magnetic order. Our conclusions are based on phenomenological considerations and on microscopic mean-field theory calculations for an illustrative toy model. We speculate on possible applications of this effect in spintronic devices.Comment: 9 pages, 6 figures, updated version as published, Journal referenc

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA

In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2

Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions