Uncovering the (un-)occupied electronic structure of a buried hybrid interface

The energy level alignment at organic/inorganic (o/i) semiconductor interfaces is crucial for any light-emitting or -harvesting functionality. Essential is the access to both occupied and unoccupied electronic states directly at the interface, which is often deeply buried underneath thick organic films and challenging to characterize. We use several complementary experimental techniques to determine the electronic structure of p-quinquephenyl pyridine (5P-Py) adsorbed on ZnO(10-10). The parent anchoring group, pyridine, significantly lowers the work function by up to 2.9 eV and causes an occupied in-gap state (IGS) directly below the Fermi level $E_\text{F}$. Adsorption of upright-standing 5P-Py also leads to a strong work function reduction of up to 2.1 eV and to a similar IGS. The latter is then used as an initial state for the transient population of three normally unoccupied molecular levels through optical excitation and, due to its localization right at the o/i interface, provides interfacial sensitivity, even for thick 5P-Py films. We observe two final states above the vacuum level and one bound state at around 2 eV above $E_\text{F}$, which we attribute to the 5P-Py LUMO. By the separate study of anchoring group and organic dye combined with the exploitation of the occupied IGS for selective interfacial photoexcitation this work provides a new pathway for characterizing the electronic structure at buried o/i interfaces

Fatigue in multiple sclerosis: Associations with clinical, MRI and CSF parameters

Background: Damage of different brain structures has been related to fatigue. Alternatively, functional alterations of central nervous system (CNS) cells by the inflammatory milieu within the CNS may be responsible for the development of fatigue. Aim: To investigate the effect of structural brain damage and inflammatory cerebrospinal fluid (CSF) changes on fatigue in multiple sclerosis (MS). Methods: We determined the association of different clinical, CSF and magnetic resonance imaging (MRI) parameters with prevalence and severity of fatigue, as measured by the Fatigue Scale for Motor and Cognitive Functions in 68 early MS patients (discovery cohort). We validated our findings in two MS cohorts: the MRI validation cohort (N=233) for the clinical and MRI parameters, and the CSF validation cohort (N=81) for the clinical and CSF parameters. Results: Fatigue was associated with clinical disability. Fatigue did not correlate with any CSF parameter but correlated negatively with total and cortical grey matter volume. However, when controlling for Expanded Disability Status Scale (EDSS) in a multivariate model, these associations lost significance. Conclusion: Disability and disease duration best explain fatigue severity but none of the tested MRI or CSF parameter was reliably associated with fatigue

Searching for prompt signatures of nearby core-collapse supernovae by a joint analysis of neutrino and gravitational-wave data

We discuss the science motivations and prospects for a joint analysis of gravitational-wave (GW) and low-energy neutrino data to search for prompt signals from nearby supernovae (SNe). Both gravitational-wave and low-energy neutrinos are expected to be produced in the innermost region of a core-collapse supernova, and a search for coincident signals would probe the processes which power a supernova explosion. It is estimated that the current generation of neutrino and gravitational-wave detectors would be sensitive to Galactic core-collapse supernovae, and would also be able to detect electromagnetically dark SNe. A joint GW-neutrino search would enable improvements to searches by way of lower detection thresholds, larger distance range, better live-time coverage by a network of GW and neutrino detectors, and increased significance of candidate detections. A close collaboration between the GW and neutrino communities for such a search will thus go far toward realizing a much sought-after astrophysics goal of detecting the next nearby supernova.Comment: 10 pages, 3 figures. To appear in Class. Quantum Gra

Alien Plants Introduced by Different Pathways Differ in Invasion Success: Unintentional Introductions as a Threat to Natural Areas

BACKGROUND: Understanding the dimensions of pathways of introduction of alien plants is important for regulating species invasions, but how particular pathways differ in terms of post-invasion success of species they deliver has never been rigorously tested. We asked whether invasion status, distribution and habitat range of 1,007 alien plant species introduced after 1500 A.D. to the Czech Republic differ among four basic pathways of introduction recognized for plants. PRINCIPAL FINDINGS: Pathways introducing alien species deliberately as commodities (direct release into the wild; escape from cultivation) result in easier naturalization and invasion than pathways of unintentional introduction (contaminant of a commodity; stowaway arriving without association with it). The proportion of naturalized and invasive species among all introductions delivered by a particular pathway decreases with a decreasing level of direct assistance from humans associated with that pathway, from release and escape to contaminant and stowaway. However, those species that are introduced via unintentional pathways and become invasive are as widely distributed as deliberately introduced species, and those introduced as contaminants invade an even wider range of seminatural habitats. CONCLUSIONS: Pathways associated with deliberate species introductions with commodities and pathways whereby species are unintentionally introduced are contrasting modes of introductions in terms of invasion success. However, various measures of the outcome of the invasion process, in terms of species' invasion success, need to be considered to accurately evaluate the role of and threat imposed by individual pathways. By employing various measures we show that invasions by unintentionally introduced plant species need to be considered by management as seriously as those introduced by horticulture, because they invade a wide range of seminatural habitats, hence representing even a greater threat to natural areas

Calibration and Characterization of the IceCube Photomultiplier Tube

Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts.Comment: 40 pages, 12 figure

Retrospective cohort study to devise a treatment decision score predicting adverse 24-month radiological activity in early multiple sclerosis

Background: Multiple sclerosis (MS) is a chronic neuroinflammatory disease affecting about 2.8 million people worldwide. Disease course after the most common diagnoses of relapsing-remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS) is highly variable and cannot be reliably predicted. This impairs early personalized treatment decisions. Objectives: The main objective of this study was to algorithmically support clinical decision-making regarding the options of early platform medication or no immediate treatment of patients with early RRMS and CIS. Design: Retrospective monocentric cohort study within the Data Integration for Future Medicine (DIFUTURE) Consortium. Methods: Multiple data sources of routine clinical, imaging and laboratory data derived from a large and deeply characterized cohort of patients with MS were integrated to conduct a retrospective study to create and internally validate a treatment decision score [Multiple Sclerosis Treatment Decision Score (MS-TDS)] through model-based random forests (RFs). The MS-TDS predicts the probability of no new or enlarging lesions in cerebral magnetic resonance images (cMRIs) between 6 and 24 months after the first cMRI. Results: Data from 65 predictors collected for 475 patients between 2008 and 2017 were included. No medication and platform medication were administered to 277 (58.3%) and 198 (41.7%) patients. The MS-TDS predicted individual outcomes with a cross-validated area under the receiver operating characteristics curve (AUROC) of 0.624. The respective RF prediction model provides patient-specific MS-TDS and probabilities of treatment success. The latter may increase by 5–20% for half of the patients if the treatment considered superior by the MS-TDS is used. Conclusion: Routine clinical data from multiple sources can be successfully integrated to build prediction models to support treatment decision-making. In this study, the resulting MS-TDS estimates individualized treatment success probabilities that can identify patients who benefit from early platform medication. External validation of the MS-TDS is required, and a prospective study is currently being conducted. In addition, the clinical relevance of the MS-TDS needs to be established

Late Pleistocene to Holocene event stratigraphy of Lake Hallstatt (Salzkammergut, Austria): revealed by the Hipercorig drilling system and borehole logging

The Hipercorig Hallstatt History (H3) project aims to unravel the entire Late Glacial to Holocene sedimentary succession recording past climate, environment, natural hazard impacts, human–environment interactions, and prehistoric mining history. We successfully cored 51 m of the sedimentary succession of Lake Hallstatt, revealing a high-resolution Late Pleistocene to Holocene sediment record, overcoming the previous coring limit of 15.63 m (dated to ∼ 2.3 ka cal BP). The novel drilling platform Hipercorig allows the recovery of undisturbed long cores and the acquisition of borehole logging data of deep lakes. The sedimentary record is spliced to a composite core profile, and for the first time borehole logging data are linked to a core–log seismic correlation of an intra-mountainous lake of the Eastern Alps. The recovered sequence consists of two major lithostratigraphic units: (i) Unit 1 (Holocene, 0–41.7 m below lake floor) with 10 (up to 5.1 m thick) instantaneous deposits and (ii) Unit 2 (Late Pleistocene, &gt; 41.7 m below lake floor). The Late Pleistocene sediments comprise the Younger Dryas and the deepest recovered sediments likely date back to the Allerød interstadial. Within the Holocene, six different periods are observed in the core and borehole logging data, showing distinct physical property fluctuations and an overall increase in sedimentation rate upcore. Lake Hallstatt provides a unique prehistoric archive, being located within the UNESCO World Heritage area Hallstatt–Dachstein/Salzkammergut, a region with a rich history of human salt mining dating back to 3400 cal BP (Middle/Late Bronze Age) and one of the oldest documented cultural landscapes worldwide.</p

Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of December 27th, 2004 with the AMANDA-II detector

On December 27th 2004, a giant gamma flare from the Soft Gamma-ray Repeater 1806-20 saturated many satellite gamma-ray detectors. This event was by more than two orders of magnitude the brightest cosmic transient ever observed. If the gamma emission extends up to TeV energies with a hard power law energy spectrum, photo-produced muons could be observed in surface and underground arrays. Moreover, high-energy neutrinos could have been produced during the SGR giant flare if there were substantial baryonic outflow from the magnetar. These high-energy neutrinos would have also produced muons in an underground array. AMANDA-II was used to search for downgoing muons indicative of high-energy gammas and/or neutrinos. The data revealed no significant signal. The upper limit on the gamma flux at 90% CL is dN/dE < 0.05 (0.5) TeV^-1 m^-2 s^-1 for gamma=-1.47 (-2). Similarly, we set limits on the normalization constant of the high-energy neutrino emission of 0.4 (6.1) TeV^-1 m^-2 s^-1 for gamma=-1.47 (-2).Comment: 14 pages, 3 figure

Detection of Atmospheric Muon Neutrinos with the IceCube 9-String Detector

The IceCube neutrino detector is a cubic kilometer TeV to PeV neutrino detector under construction at the geographic South Pole. The dominant population of neutrinos detected in IceCube is due to meson decay in cosmic-ray air showers. These atmospheric neutrinos are relatively well-understood and serve as a calibration and verification tool for the new detector. In 2006, the detector was approximately 10% completed, and we report on data acquired from the detector in this configuration. We observe an atmospheric neutrino signal consistent with expectations, demonstrating that the IceCube detector is capable of identifying neutrino events. In the first 137.4 days of livetime, 234 neutrino candidates were selected with an expectation of 211 +/- 76.1(syst.) +/- 14.5(stat.) events from atmospheric neutrinos