The Boson peak in supercooled water

We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line $T_W$. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih.Comment: 25 pages, 9 figure

First ice core records of NO3− stable isotopes from Lomonosovfonna, Svalbard

Samples from two ice cores drilled at Lomonosovfonna, Svalbard, covering the period 1957–2009, and 1650–1995, respectively, were analyzed for NO3− concentrations, and NO3− stable isotopes (δ15N and δ18O). Post-1950 δ15N has an average of (−6.9 ± 1.9) ‰, which is lower than the isotopic signal known for Summit, Greenland, but agrees with values observed in recent Svalbard snow and aerosol. Pre-1900 δ15N has an average of (4.2 ± 1.6) ‰ suggesting that natural sources, enriched in the 15 N-isotope, dominated before industrialization. The post-1950 δ18O average of (75.1 ± 4.1) ‰ agrees with data from low and polar latitudes, suggesting similar atmospheric NOy (NOy = NO + NO2 + HNO3) processing pathways. The combination of anthropogenic source δ15N and transport isotope effect was estimated as −29.1 ‰ for the last 60 years. This value is below the usual range of NOx (NOx = NO + NO2) anthropogenic sources which is likely the result of a transport isotope effect of –32 ‰. We suggest that the δ15N recorded at Lomonosovfonna is influenced mainly by fossil fuel combustion, soil emissions and forest fires; the first and second being responsible for the marked decrease in δ15N observed in the post-1950s record with soil emissions being associated to the decreasing trend in δ15N observed up to present time, and the third being responsible for the sharp increase of δ15N around 2000

The information system for LHC parameters and layouts

The construction of the Large Hadron Collider, LHC, at CERN implies both the handling of a huge amount of information and the control of the coherence of this information. The LHC machine parameters have to be maintained coherent as the design evolves from the conceptual stage to the actual, installed, machine and have to be made available to all concerned. Design data is provided in many different formats from the machine builders, drawings, technical documents, meeting notes, lattice simulation input files, etc. The World Wide Web is being used to make the information accessible both at CERN and at the external collaborating laboratories. In this paper we describe the implementation of an Oracle database as the central common repository for machine parameters and of information for the automatic generation of CAD layout drawings and WWW pages. This system is integrated in a larger context, the EDMS system for the LHC project, which encompasses both the accelerator and the experiments

Sinking and floating rates of natural phytoplankton assemblages in Lake Erken

Sinking rates of the <120 mu m size phytoplankton fraction of water from Lake Erken were determined during the summer 1992 by following the increase of chlorophyll a in the 10 ml-bottom layer in replicate 100 ml settling cylinders. Changes in chlorophyll a concentrations as a function of incubation time allowed two fractions to be separated. Fast sinking rates varied between values of 1.9 m/day when pennate and centric diatoms and coccal cyanobacteria were dominant tin cell concentration) and values of 0.5 m/day when cryptophytes and chrysophytes dominated the <120 mu m size fraction. Slow sinking rates decreased from 0.04 m/day at the beginning of July to 0.02 m/day in late July. Photosynthesis-Irradiance parameters (P-max(B) light saturated photosynthesis and #alpha#(B), light limited photosynthesis) were lower in the fast sinking fraction (P-max(B) = 1.3 - 2.4 mu gC/mu gChl/h and #alpha#(B) = 0.01 - 0.04 mu gC/mu gChl/h/(mu E/m(2)/s) than in the slow or non-sinking one (P-max(B) = 3.9 - 6.4 mu gC/mu gChl/h and #alpha#(B) = 0.03 - 0.08 mu gC/mu gChl/h/(mu E/m(2)/s). P-max(B) and #alpha#B of the planktonic Gloeotrichia echinulata, a colonial broom-forming cyanobacterium, were similar to those found in the fast sinking fraction. Mean floating rates of G. echinulata were around 43 m/d from 15 to 27 July and increased by a factor of two afterwards. G. echinulata colonies migrating upwards from sediments and captured in inverted traps showed a mean floating rate of 104 m/d

Cost optimization of biofuel production – The impact of scale, integration, transport and supply chain configurations

This study uses a geographically-explicit cost optimization model to analyze the impact of and interrelation between four cost reduction strategies for biofuel production: economies of scale, intermodal transport, integration with existing industries, and distributed supply chain configurations (i.e. supply chains with an intermediate pre-treatment step to reduce biomass transport cost). The model assessed biofuel production levels ranging from 1 to 150 PJ a−1 in the context of the existing Swedish forest industry. Biofuel was produced from forestry biomass using hydrothermal liquefaction and hydroprocessing. Simultaneous implementation of all cost reduction strategies yielded minimum biofuel production costs of 18.1–18.2 € GJ−1 at biofuel production levels between 10 and 75 PJ a−1. Limiting the economies of scale was shown to cause the largest cost increase (+0–12%, increasing with biofuel production level), followed by disabling integration benefits (+1–10%, decreasing with biofuel production level) and allowing unimodal truck transport only (+0–6%, increasing with biofuel production level). Distributed supply chain configurations were introduced once biomass supply became increasingly dispersed, but did not provide a significant cost benefit (<1%). Disabling the benefits of integration favors large-scale centralized production, while intermodal transport networks positively affect the benefits of economies of scale. As biofuel production costs still exceeds the price of fossil transport fuels in Sweden after implementation of all cost reduction strategies, policy support and stimulation of further technological learning remains essential to achieve cost parity with fossil fuels for this feedstock/technology combination in this spatiotemporal context

Feeling controlled or being in control? Apps for self-management among older people with neurological disability

Purpose: The aim of this paper was to describe how people living with a neurological disability such as multiple sclerosis, Parkinson’s disease and stroke reason regarding using apps to facilitate self-management in everyday life. Material and methods: A qualitative research approach with a focus group methodology was used. The sample comprised 16 participants, 11 men and 5 women, with an average age of 64 years (ranging from 51–80 years). Six participants were diagnosed with multiple sclerosis, six with Parkinson’s disease and four with stroke. Data were analyzed using thematic analysis, which is a method for identifying, analyzing and reporting patterns. Results: The results formed two themes. The first theme “using apps to have control of my health” comprises two subthemes; “monitor and take responsibility for a healthy lifestyle” and “compensate to facilitate everyday life”. The second theme “using the app as a tool and means for communication” also comprised two subthemes; “dare to trust the app” and “feeling safe when sharing information with health care professionals”. Conclusions: The use of apps put increased responsibility on the person and had the possibility to make them more involved in their own care. The use of an app can facilitate a healthy lifestyle and help to monitor disease-specific symptoms. In order to be able to use apps for communication with the health care sector legislation and safety issues need to be considered. Implications for rehabilitation Apps can be used for self-management if they are safe and can be trusted. People with neurological disabilities want to be involved in their healthcare and needs to be addressed by health care professionals. The use of apps grasp over a wide variety of areas this is something that may be considered in health care and something that can be addressed by interdisciplinary approaches. Ordinary health-oriented apps and disease-specific apps were used differently and for different purposes

Mass measurements in the vicinity of the doubly-magic waiting point 56Ni

Masses of 56,57Fe, 53Co^m, 53,56Co, 55,56,57Ni, 57,58Cu, and 59,60Zn have been determined with the JYFLTRAP Penning trap mass spectrometer at IGISOL with a precision of dm/m \le 3 x 10^{-8}. The QEC values for 53Co, 55Ni, 56Ni, 57Cu, 58Cu, and 59Zn have been measured directly with a typical precision of better than 0.7 keV and Coulomb displacement energies have been determined. The Q values for proton captures on 55Co, 56Ni, 58Cu, and 59Cu have been measured directly. The precision of the proton-capture Q value for 56Ni(p,gamma)57Cu, Q(p,gamma) = 689.69(51) keV, crucial for astrophysical rp-process calculations, has been improved by a factor of 37. The excitation energy of the proton emitting spin-gap isomer 53Co^m has been measured precisely, Ex = 3174.3(10) keV, and a Coulomb energy difference of 133.9(10) keV for the 19/2- state has been obtained. Except for 53Co, the mass values have been adjusted within a network of 17 frequency ratio measurements between 13 nuclides which allowed also a determination of the reference masses 55Co, 58Ni, and 59Cu.Comment: 14 pages, 13 figures, submitted to Phys. Rev.

Luminescence from highly excited nanorings: Luttinger liquid description

We study theoretically the luminescence from quantum dots of a ring geometry. For high excitation intensities, photoexcited electrons and holes form Fermi seas. Close to the emission threshold, the single-particle spectral lines aquire weak many-body satellites. However, away from the threshold, the discrete luminescence spectrum is completely dominated by many-body transitions. We employ the Luttinger liquid approach to exactly calculate the intensities of all many-body spectral lines. We find that the transition from single-particle to many-body structure of the emission spectrum is governed by a single parameter and that the distribution of peaks away from the threshold is universal.Comment: 10 pages including 2 figure

The structure of mixed H2O-OH monolayer films on Ru(0001)

Scanning tunneling microscopy (STM) and x-ray absorption spectroscopy (XAS) have been used to study the structures produced by water on Ru(0001) at temperatures above 140 K. It was found that while undissociated water layers are metastable below 140 K, heating above this temperature produces drastic transformations whereby a fraction of the water molecules partially dissociate and form mixed H{sub 2}O-OH structures. XPS and XAS revealed the presence of hydroxyl groups with their O-H bond essentially parallel to the surface. STM images show that the mixed H{sub 2}O-OH structures consist of long narrow stripes aligned with the three crystallographic directions perpendicular to the close-packed atomic rows of the Ru(0001) substrate. The internal structure of the stripes is a honeycomb network of H-bonded water and hydroxyl species. We found that the metastable low temperature molecular phase can also be converted to a mixed H{sub 2}O-OH phase through excitation by the tunneling electrons when their energy is 0.5 eV or higher above the Fermi level. Structural models based on the STM images were used for Density Functional Theory optimizations of the stripe geometry. The optimized geometry was then utilized to calculate STM images for comparison with the experiment

Wong-Zakai approximation of solutions to reflecting stochastic differential equations on domains in Euclidean spaces II

The strong convergence of Wong-Zakai approximations of the solution to the reflecting stochastic differential equations was studied in [2]. We continue the study and prove the strong convergence under weaker assumptions on the domain.Comment: To appear in "Stochastic Analysis and Applications 2014-In Honour of Terry Lyons", Springer Proceedings in Mathematics and Statistic