The origin of oriented lakes: evidence from the Bolivian Amazon

The presence of hundreds of rectangular and oriented lakes is one of the most striking characteristics of the Llanos de Moxos (LM) landscape in the Bolivian Amazon. Oriented lakes also occur in the Arctic coastal plains of Russia, Alaska and Canada and along the Atlantic Coastal Plain from northeast Florida to southeast New Jersey and along the coast of northeast Brazil. Many different mechanisms have been proposed for their formation. In the LM, Plafker's (1964) tectonic model, in which subsidence results from the propagation of bedrock faults through the foreland sediments, is the most accepted. However, this model has not been verified. Here, we present new results from stratigraphic transects across the borders of three rectangular and oriented lakes in the LM. A paleosol buried under mid-Holocene sediments is used as a stratigraphic marker to assess the vertical displacement of sediments on both sides of the alleged faults. Our results show that there is no vertical displacement and, therefore, that Plafker's model can be ruled out. We suggest that, among all the proposed mechanisms behind lake formation, the combined action of wind and waves is the most likely. The evidence from the LM provides new hints for the formation of oriented lakes worldwide.

X-ray image calibration and its application to clinical orthopedics.

X-ray imaging is one of the most commonly used medical imaging modality. Albeit X-ray radiographs provide important clinical information for diagnosis, planning and post-operative follow-up, the challenging interpretation due to its 2D projection characteristics and the unknown magnification factor constrain the full benefit of X-ray imaging. In order to overcome these drawbacks, we proposed here an easy-to-use X-ray calibration object and developed an optimization method to robustly find correspondences between the 3D fiducials of the calibration object and their 2D projections. In this work we present all the details of this outlined concept. Moreover, we demonstrate the potential of using such a method to precisely extract information from calibrated X-ray radiographs for two different orthopedic applications: post-operative acetabular cup implant orientation measurement and 3D vertebral body displacement measurement during preoperative traction tests. In the first application, we have achieved a clinically acceptable accuracy of below 1° for both anteversion and inclination angles, where in the second application an average displacement of 8.06±3.71 mm was measured. The results of both applications indicate the importance of using X-ray calibration in the clinical routine.

Testing the Weak Equivalence Principle with an antimatter beam at CERN

The goal of the AEgIS experiment is to measure the gravitational acceleration of antihydrogen – the simplest atom consisting entirely of antimatter – with the ultimate precision of 1%. We plan to verify the Weak Equivalence Principle (WEP), one of the fundamental laws of nature, with an antimatter beam. The experiment consists of a positron accumulator, an antiproton trap and a Stark accelerator in a solenoidal magnetic field to form and accelerate a pulsed beam of antihydrogen atoms towards a free-fall detector. The antihydrogen beam passes through a moir ́e deflectometer to measure the vertical displacement due to the gravitational force. A position and time sensitive hybrid detector registers the annihilation points of the antihydrogen atoms and their time-of-flight. The detection principle has been successfully tested with antiprotons and a miniature moir ́e deflectometer coupled to a nuclear emulsion detector.

Measurement of the differential cross-section of B⁺ meson production in pp collisions at sqrts = 7 TeV at ATLAS

The production cross-section of B+ mesons is measured as a function of transverse momentum p T and rapidity y in proton-proton collisions at centre-of-mass energy root s = 7 TeV, using 2.4 fb(-1) of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < p(T) < 120 GeV and vertical bar y vertical bar < 2.25, are compared to next-to-leading-order theoretical predictions.

Measurement of Upsilon production in 7 TeV pp collisions at ATLAS

Using 1.8 fb(-1) of pp collisions at a center- of- mass energy of 7 TeV recorded by the ATLAS detector at the Large Hadron Collider, we present measurements of the production cross sections of Upsilon(1S,2S,3S) mesons. Upsilon mesons are reconstructed using the dimuon decay mode. Total production cross sections for p(T) < 70 GeV and in the rapidity interval vertical bar y(Upsilon)vertical bar < 2. 25 are measured to be, 8.01 +/- 0.02 +/- 0.36 +/- 0.31 nb, 2.05 +/- 0.01 +/- 0.12 +/- 0.08 nb, and 0.92 +/- 0.01 +/- 0.07 +/- 0.04 nb, respectively, with uncertainties separated into statistical, systematic, and luminosity measurement effects. In addition, differential cross section times dimuon branching fractions for Upsilon(1S), Upsilon(2S), and Upsilon(3S) as a function of Upsilon transverse momentum pT and rapidity are presented. These cross sections are obtained assuming unpolarized production. If the production polarization is fully transverse or longitudinal with no azimuthal dependence in the helicity frame, the cross section may vary by approximately +/- 20%. If a nontrivial azimuthal dependence is considered, integrated cross sections may be significantly enhanced by a factor of 2 or more. We compare our results to several theoretical models of Upsilon meson production, finding that none provide an accurate description of our data over the full range of Upsilon transverse momenta accessible with this data set.

Measurement of isolated-photon pair production in pp collisions at sqrts=7 TeV with the ATLAS detector

The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at root s = 7 TeV. The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb(-1), is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (vertical bar eta vertical bar < 1.37 and 1.52 < vertical bar eta vertical bar 2.37) and with an angular separation Delta R > 0.4, is 44.0(-4.2)(+3.2) pb. The differential cross sections as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cosine of the polar angle of the largest transverse energy photon in the Collins-Soper di-photon rest frame are also measured. The results are compared to the prediction of leading-order parton-shower and next-to-leading-order and next-to-next-to-leading-order parton-level generators.

Measurement of the flavour composition of dijet events in pp collisions at sqrts=7 TeV with the AT detector

This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at root s = 7 TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb(-1). Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity vertical bar y vertical bar < 2.1. The fit results agree with the predictions of leading-and next-to-leading-order calculations, with the exception of the dijet fraction composed of bottom and light flavour jets, which is underestimated by all models at large transverse jet momenta. The ability to identify jets containing two b-hadrons, originating from e. g. gluon splitting, is demonstrated. The difference between bottom jet production rates in leading and subleading jets is consistent with the next-to-leading-order predictions.

Measurement of the jet radius and transverse momentum dependence of inclusive jet suppression in lead-lead collisions at sqrtsNN=2.76 TeV with the AT detector

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at root S-NN = 2.76 TeV corresponding to an integrated luminosity of approximately 7 mu b(-1), ATLAS has measured jets with a calorimeter system over the pseudorapidity interval vertical bar eta vertical bar < 2.1 and over the transverse momentum range 38 < pT <210 GeV. Jets were reconstructed using the anti-k(t) algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," R-CP. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. R-CP varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.

Measurement of the production cross section of jets in association with a Z boson in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

Measurements of the production of jets of particles in association with a Z boson in pp collisions at root s = 7 TeV are presented, using data corresponding to an integrated luminosity of 4.6 fb(-1) collected by the ATLAS experiment at the Large Hadron Collider. Inclusive and differential jet cross sections in Z events, with Z decaying into electron or muon pairs, are measured for jets with transverse momentum p(T) > 30 GeV and rapidity vertical bar y vertical bar < 4.4. The results are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements supplemented by parton showers.

Measurement of the inclusive jet cross section in pp collisions at sqrt(s)=2.76 TeV and comparison to the inclusive jet cross section at sqrt(s)=7 TeV using the ATLAS detector

The inclusive jet cross-section has been measured in proton-proton collisions at root s = 2.76 TeV in a dataset corresponding to an integrated luminosity of 0.20 pb(-1) collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-k(t) algorithm with two radius parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section is presented as a function of the jet transverse momentum p(T) and jet rapidity y, covering a range of 20 <= p(T) < 430 GeV and vertical bar y vertical bar < 4.4. The ratio of the cross-section to the inclusive jet cross-section measurement at root s = 7 TeV, published by the ATLAS Collaboration, is calculated as a function of both transverse momentum and the dimensionless quantity x(T) = 2p(T)/root s, in bins of jet rapidity. The systematic uncertainties on the ratios are significantly reduced due to the cancellation of correlated uncertainties in the two measurements. Results are compared to the prediction from next-to-leading order perturbative QCD calculations corrected for non-perturbative effects, and next-to-leading order Monte Carlo simulation. Furthermore, the ATLAS jet cross-section measurements at root s = 2.76 TeV and root s = 7 TeV are analysed within a framework of next-to-leading order perturbative QCD calculations to determine parton distribution functions of the proton, taking into account the correlations between the measurements.

Measurement of hard double-parton interactions in W→lv+ 2 jet events at sqrt(s)=7 TeV with the ATLAS detector

The production of W bosons in association with two jets in proton-proton collisions at a centre-of-mass energy of root s = 7 TeV has been analysed for the presence of double-parton interactions using data corresponding to an integrated luminosity of 36 pb(-1), collected with the ATLAS detector at the Large Hadron Collider. The fraction of events arising from double-parton interactions, f(DP)((D)), has been measured through the p(T) balance between the two jets and amounts to f(DP)((D)) = 0.08 +/- 0.01 (stat.) +/- 0.02 (sys.) for jets with transverse momentum p(T) > 20 GeV and rapidity vertical bar y vertical bar < 2.8. This corresponds to a measurement of the effective area parameter for hard double-parton interactions of sigma(eff) = 15 +/- 3 (stat.)(-3)(+5) (sys.) mb.

Terrestrial Radar Interferometric Measurement of Hillslope Deformation and Atmospheric Disturbances in the Illgraben Debris-Flow Catchment, Switzerland

We describe a method for rapid identification and precise quantification of slope deformation using a portable radar interferometer. A rockslide with creep-like behavior was identified in the rugged and inaccessible headwaters of the Illgraben debris-flow catchment, located in the Central Swiss Alps. The estimated volume of the moving rock mass was approximately 0.5 x 10(6) m(3) with a maximum daily (3-D) displacement rate of 3 mm. Fast scene acquisition in the order of 6 s/scene led to uniquely precise mapping of spatial and temporal variability of atmospheric phase delay. Observations led to a simple qualitative model for prediction of atmospheric disturbances using a simple model for solar radiation, which can be used for advanced campaign planning for short observation periods (hours to days).

GROMOS-C, a novel ground-based microwave radiometer for ozone measurement campaigns

Stratospheric ozone is of major interest as it absorbs most harmful UV radiation from the sun, allowing life on Earth. Ground-based microwave remote sensing is the only method that allows for the measurement of ozone profiles up to the mesopause, over 24 hours and under different weather conditions with high time resolution. In this paper a novel ground-based microwave radiometer is presented. It is called GROMOS-C (GRound based Ozone MOnitoring System for Campaigns), and it has been designed to measure the vertical profile of ozone distribution in the middle atmosphere by observing ozone emission spectra at a frequency of 110.836 GHz. The instrument is designed in a compact way which makes it transportable and suitable for outdoor use in campaigns, an advantageous feature that is lacking in present day ozone radiometers. It is operated through remote control. GROMOS-C is a total power radiometer which uses a pre-amplified heterodyne receiver, and a digital fast Fourier transform spectrometer for the spectral analysis. Among its main new features, the incorporation of different calibration loads stands out; this includes a noise diode and a new type of blackbody target specifically designed for this instrument, based on Peltier elements. The calibration scheme does not depend on the use of liquid nitrogen; therefore GROMOS-C can be operated at remote places with no maintenance requirements. In addition, the instrument can be switched in frequency to observe the CO line at 115 GHz. A description of the main characteristics of GROMOS-C is included in this paper, as well as the results of a first campaign at the High Altitude Research Station at Jungfraujoch (HFSJ), Switzerland. The validation is performed by comparison of the retrieved profiles against equivalent profiles from MLS (Microwave Limb Sounding) satellite data, ECMWF (European Centre for Medium-Range Weather Forecast) model data, as well as our nearby NDACC (Network for the Detection of Atmospheric Composition Change) ozone radiometer measuring at Bern.

Pelvic floor muscle displacement during voluntary and involuntary activation in continent and incontinent women: a systematic review.

INTRODUCTION Investigations of the dynamic function of female pelvic floor muscles (PFM) help us to understand the pathophysiology of stress urinary incontinence (SUI). Displacement measurements of PFM give insight into muscle activation and thus help to improve rehabilitation strategies. This systematic review (PROSPERO 2013: CRD42013006409) was performed to summarise the current evidence for PFM displacement during voluntary and involuntary activation in continent and incontinent women. METHODS MEDLINE, EMBASE, Cochrane and SPORTDiscus databases were searched using selected terminology reflecting the PICO approach. Screening of Google Scholar and congress abstracts added to further information. Original articles investigating PFM displacement were included if they reported on at least one of the aims of the review, e.g., method, test position, test activity, direction and quantification of displacement, as well as the comparison between continent and incontinent women. Titles and abstracts were screened by two reviewers. The papers included were reviewed by two individuals to ascertain whether they fulfilled the inclusion criteria and data were extracted on outcome parameters. RESULTS Forty-two predominantly observational studies fulfilled the inclusion criteria. A variety of measurement methods and calculations of displacement was presented. The sample was heterogeneous concerning age, parity and continence status. Test positions and test activities varied among the studies. CONCLUSIONS The findings summarise the present knowledge of PFM displacement, but still lack deeper comprehension of the SUI pathomechanism of involuntary, reflexive activation during functional activities. We therefore propose that future investigations focus on PFM dynamics during fast and stressful impact tasks.