240 research outputs found

    Structural and Functional Analyses of Liver Cysts from the BALB/c-cpk Mouse Model of Polycystic Kidney Disease

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    Liver cysts arising from hepatic bile ducts are a common extra-renal pathology associated with both autosomal dominant and recessive polycystic kidney disease in humans. To elucidate the functional and structural changes inherent in cyst formation and growth, hepatic bile duct epithelia were isolated from the BALB/ c-cpk mouse model of polycystic kidney disease. Light and transmission electron microscopy revealed substantial fibrosis in the basal lamina surrounding hepatic bile duct cysts isolated from heterozygous (BALB/c-cpk/+) and homozygous (BALB/c-cpk/cpk) animals. Scanning electron microscopy and length analysis of normal, precystic and cystic bile ducts provided the unique observation that primary cilia in cholangiocytes isolated from bile ducts and cysts of animals expressing the mutated cpk gene had lengths outside the minimal and maximal ranges of those in cells lining bile ducts of wild-type animals. Based on the hypothesis that PKD is one of several diseases characterized as ciliopathies, this abnormal variability in the length of the primary cilia may have functional implications. Electrophysiological analyses of freshly isolated cysts indicate that the amiloride-sensitive epithelial Na(+) channel (ENaC) is inactive/absent and cAMP-mediated anion secretion is the electrogenic transport process contributing to cyst fluid accumulation. Anion secretion can be stimulated by the luminal stimulation of adenylyl cyclase

    Eteokles in Spain? On Brecht’s Mein Bruder war ein Flieger

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    One of Bertolt Brecht’s most famous poems, Mein Bruder war ein Flieger, is often invoked as a manifesto for pacifist ideals, but some essential questions (who is the lyric I? what is the literal meaning of the poem?) have hardly received any attention. By evoking the poem’s nature as a Kinderlied, the context of its first publication, and its relationship with Brecht’s play Die Gewehre der Frau Carrar, this article tentatively identifies the source of its final pointe in a famous passage of Aeschylus’ Seven against Thebes, thereby suggesting—on the basis of textual comparisons—an example of far-reaching, ideological Antikerezeption in Brecht’s oeuvre, working all the way down to his Kalendergeschichten and to his Antigone

    Front-end electronics for the ALICE TPC-detector

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    The Front-End electronics for the Time Projection Chamber (TPC) for the ALICE experiment consists of 5x105 channels. A single readout channel is comprised of three basic units: a charge sensitive amplifier/shaper with a fast tail cancellation; a 10 bit 10 Msamples/sec low power ADC; a digital ASIC which contains the zero suppression circuit and a multiple-event buffer. Data from a number of channels (4096) are multiplexed into an optical link (DDL) by means of a local custom bus which can support a data throughput of 2 Mbyte/event at a trigger rate of 50 Hz. The construction of a prototype of this electronics is presented in this paper

    Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries

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    We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.Comment: 17 page

    Measurement of the proton and deuteron structure functions, F2p and F2d, and of the ratio sigma(L)/sigma(T)

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    The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q2 < 75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results are based on the full data set collected by the New Muon Collaboration, including the data taken with a small angle trigger. The extracted values of the structure functions F2p and F2d are in good agreement with those from other experiments. The data cover a sufficient range of y to allow the determination of the ratio of the longitudinally to transversely polarised virtual photon absorption cross sections, R= sigma(L)/sigma(T), for 0.002 < x < 0.12 . The values of R are compatible with a perturbative QCD prediction; they agree with earlier measurements and extend to smaller x.Comment: In this replacement the erroneously quoted R values in tables 3-6 for x>0.12, and R1990 values in tables 5-6 for all x, have been corrected, and the cross sections in tables 3-4 have been adapted. Everything else, including the structure functions F2, remained unchanged. 22 pages, LateX, including figures, with two .sty files, and three separate f2tab.tex files for the F2-tables. Accepted for publication in Nucl.Phys.B 199

    Large enhancement of deuteron polarization with frequency modulated microwaves

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    We report a large enhancement of 1.7 in deuteron polarization up to values of 0.6 due to frequency modulation of the polarizing microwaves in a two liters polarized target using the method of dynamic nuclear polarization. This target was used during a deep inelastic polarized muon-deuteron scattering experiment at CERN. Measurements of the electron paramagnetic resonance absorption spectra show that frequency modulation gives rise to additional microwave absorption in the spectral wings. Although these results are not understood theoretically, they may provide a useful testing ground for the deeper understanding of dynamic nuclear polarization.Comment: 10 pages, including the figures coming in uuencoded compressed tar files in poltar.uu, which also brings cernart.sty and crna12.sty files neede

    Spin Structure of the Proton from Polarized Inclusive Deep-Inelastic Muon-Proton Scattering

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    We have measured the spin-dependent structure function g1pg_1^p in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range 0.003<x<0.70.003 < x < 0.7 and 1GeV2<Q2<60GeV21 GeV^2 < Q^2 < 60 GeV^2. A next-to-leading order QCD analysis is used to evolve the measured g1p(x,Q2)g_1^p(x,Q^2) to a fixed Q02Q^2_0. The first moment of g1pg_1^p at Q02=10GeV2Q^2_0 = 10 GeV^2 is Γp=0.136±0.013(stat.)±0.009(syst.)±0.005(evol.)\Gamma^p = 0.136\pm 0.013(stat.) \pm 0.009(syst.)\pm 0.005(evol.). This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge a0a_0 is found to be 0.28±0.160.28 \pm 0.16. In the Adler-Bardeen factorization scheme, Δg≃2\Delta g \simeq 2 is required to bring ΔΣ\Delta \Sigma in agreement with the Quark-Parton Model. A combined analysis of all available proton and deuteron data confirms the Bjorken sum rule.Comment: 33 pages, 22 figures, uses ReVTex and smc.sty. submitted to Physical Review

    A Re-Evaluation of the nuclear Structure Function Ratios for D, He, Li, C and Ca

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    We present a re-evaluation of the structure function ratios F2(He)/F2(D), F2(C)/F2(D) and F2(Ca)/F2(D) measured in deep inelastic muon-nucleus scattering at an incident muon momentum of 200 GeV. We also present the ratios F2(C)/F2(Li), F2(Ca)/F2(Li) and F2(Ca)/F2(C) measured at 90 GeV. The results are based on data already published by NMC; the main difference in the analysis is a correction for the masses of the deuterium targets and an improvement in the radiative corrections. The kinematic range covered is 0.0035 < x < 0.65, 0.5 < Q^2 <90 GeV^2 for the He/D, C/D and Ca/D data and 0.0085 < x < 0.6, 0.84 < Q^2 < 17 GeV^2 for the Li/C/Ca ones.Comment: 6 pages, Latex, 3 figures as uuencoded compressed tar file included at the end, in case of problems contact [email protected] (Antje Bruell

    Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries

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    We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031~GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10~GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) {\rm d}x = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) {\rm d}x = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) {\rm d}x= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) {\rm d}x.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments ∫01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, ∫01Δdv(x)dx=−0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and ∫01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions ∫01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0031 GeV 2 . Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q 2 =10 GeV 2 . The polarised u valence quark distribution, Δu v ( x ), is positive and the polarisation increases with x . The polarised d valence quark distribution, Δd v ( x ), is negative and the non-strange sea distribution, Δ q ̄ (x) , is consistent with zero over the measured range of x . We find for the first moments ∫ 0 1 Δu v (x) d x=0.77±0.10±0.08 , ∫ 0 1 Δd v (x) d x=−0.52±0.14±0.09 and ∫ 0 1 Δ q ̄ (x) d x=0.01±0.04±0.03 , where we assumed Δ u ̄ (x)=Δ d ̄ (x) . We also determine for the first time the second moments of the valence distributions ∫ 0 1 xΔq v (x) d x
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