Large amplitude oscillatory motion along a solar filament

Large amplitude oscillations of solar filaments is a phenomenon known for more than half a century. Recently, a new mode of oscillations, characterized by periodical plasma motions along the filament axis, was discovered. We analyze such an event, recorded on 23 January 2002 in Big Bear Solar Observatory H$\alpha$ filtergrams, in order to infer the triggering mechanism and the nature of the restoring force. Motion along the filament axis of a distinct buldge-like feature was traced, to quantify the kinematics of the oscillatory motion. The data were fitted by a damped sine function, to estimate the basic parameters of the oscillations. In order to identify the triggering mechanism, morphological changes in the vicinity of the filament were analyzed. The observed oscillations of the plasma along the filament was characterized by an initial displacement of 24 Mm, initial velocity amplitude of 51 km/s, period of 50 min, and damping time of 115 min. We interpret the trigger in terms of poloidal magnetic flux injection by magnetic reconnection at one of the filament legs. The restoring force is caused by the magnetic pressure gradient along the filament axis. The period of oscillations, derived from the linearized equation of motion (harmonic oscillator) can be expressed as $P=\pi\sqrt{2}L/v_{A\phi}\approx4.4L/v_{A\phi}$, where $v_{A\phi} =B_{\phi0}/\sqrt{\mu_0\rho}$ represents the Alfv\'en speed based on the equilibrium poloidal field $B_{\phi0}$. Combination of our measurements with some previous observations of the same kind of oscillations shows a good agreement with the proposed interpretation.Comment: Astron. Astrophys., 2007, in pres

Study on Commissioning Process for Control Logic of Thermal Storage System

The Heating, Ventilation, and Air-Conditioning (HVAC) System Control Logic Tracer, or 'CLT' , can trace the control moves of an HVAC system and display it on a flowchart based on operation data collected in BEMS. Through comparison between estimates and measurements of the control output, the CLT can detect faults relating to operation. The present paper reports the result of commissioning of a heat exchanger secondary control in a thermal storage system in an actual building using the CLT

The complete mitochondrial genome of the broad-winged damselfly <i>Mnais costalis</i> Selys (Odonata: Calopterygidae) obtained by next-generation sequencing

<p>We used next-generation sequencing to characterise the complete mitochondrial genome of the damselfly <i>Mnais costalis</i> (Odonata, Calopterygidae). Illumina paired end reads were mapped against COI and 16S sequences from <i>M. costalis</i> and then extended using an iterative <i>de novo</i> map procedure. The final assembly was a contiguous sequence of 15,487 bp, which contained all standard mitochondrial coding regions and the putative A+T rich region. The gene configuration of the <i>M. costalis</i> mitogenome is similar to that of other odonates, comprising 13 protein-coding genes, large and small rRNA genes, and 22 tRNA genes. We found three intergenic spacers that are also present in all available whole odonate mitogenomes. Base composition of the <i>M. costalis</i> mitogenome is 40% (A), 20% (C), 14% (G) and 26% (T), with a high A+T content (66%). The characterisation of the complete mitochondrial genome of <i>M. costalis</i> adds to the growing list of mitogenomes currently available for odonates, and will help to improve primer design for future population genetic studies. A phylogenetic analysis including the currently available mitochondrial genome sequences of odonates suggests that <i>Epiophlebia superstes</i> is more closely related to the Zygoptera than to the Anisoptera.</p

Small Scale Clustering in the Isotropic Arrival Distribution of Ultra-High Energy Cosmic Rays and Implications for Their Source Candidates

We present numerical simulations on the propagation of UHE protons with energies of $(10^{19.5}-10^{22})$ eV in extragalactic magnetic fields over 1 Gpc. We use the ORS galaxy sample, which allow us to accurately quantify the contribution of nearby sources to the energy spectrum and the arrival distribution, as a source model. We calculate three observable quantities, cosmic ray spectrum, harmonic amplitude, and two point correlation function from our data of numerical simulations. With these quantities, we compare the results of our numerical calculations with the observation. We show that the three observable quantities including the GZK cutoff of the energy spectrum can be reproduced in the case that the number fraction $\sim 10^{-1.7}$ of the ORS galaxies more luminous than -20.5 mag is selected as UHECR sources. In terms of the source number density, this constraint corresponds to $10^{-6}$ Mpc$^{-3}$. However, since mean number of sources within the GZK sphere is only $\sim 0.5$ in this case, the AGASA 8 events above $10^{20.0}$ eV, which do not constitute the clustered events with each other, can not be reproduced. On the other hand, if the cosmic ray flux measured by the HiRes, which is consistent with the GZK cutoff, is correct and observational features about the arrival distribution of UHECRs are same as the AGASA, our source model can explain both the arrival distribution and the flux at the same time. Thus, we conclude that large fraction of the AGASA 8 events above $10^{20}$ eV might originate in the topdown scenarios, or that the cosmic ray flux measured by the HiRes experiment might be better. We also discuss the origin of UHECRs below $10^{20.0}$ eV through comparisons between the number density of astrophysical source candidates and our result ($\sim 10^{-6}$ Mpc$^{-3}$).Comment: 17 pages, 22 figures, 1 table. accepted version for publication in the Astrophysical Journa

Acoustic mapping velocimetry

Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments

Damping mechanisms for oscillations in solar prominences

Small amplitude oscillations are a commonly observed feature in prominences/filaments. These oscillations appear to be of local nature, are associated to the fine structure of prominence plasmas, and simultaneous flows and counterflows are also present. The existing observational evidence reveals that small amplitude oscillations, after excited, are damped in short spatial and temporal scales by some as yet not well determined physical mechanism(s). Commonly, these oscillations have been interpreted in terms of linear magnetohydrodynamic (MHD) waves, and this paper reviews the theoretical damping mechanisms that have been recently put forward in order to explain the observed attenuation scales. These mechanisms include thermal effects, through non-adiabatic processes, mass flows, resonant damping in non-uniform media, and partial ionization effects. The relevance of each mechanism is assessed by comparing the spatial and time scales produced by each of them with those obtained from observations. Also, the application of the latest theoretical results to perform prominence seismology is discussed, aiming to determine physical parameters in prominence plasmas that are difficult to measure by direct means.Comment: 36 pages, 16 figures, Space Science Reviews (accepted

Rounding of low serum creatinine levels and consequent impact on accuracy of bedside estimates of renal function in cancer patients

To compare glomerular filtration rate measured by technetium-99m ([Tc(99m)]) DTPA clearance with estimated creatinine clearance (CrCl) (Cockcroft and Gault (C&G) method) in patients with serum creatinine (Scr) levels 100 ml min(-1). This work indicates that when bedside estimates of renal function are calculated using the C&G formula actual Scr should be used first to estimate CrCl. If the resultant CrCl is </=100 ml min(-1), then the Scr should be rounded up to 0.06 mmol l(-1) and CrCl recalculated. Further assessment of this approach is warranted in a larger cohort of patients

Physics of Solar Prominences: II - Magnetic Structure and Dynamics

Observations and models of solar prominences are reviewed. We focus on non-eruptive prominences, and describe recent progress in four areas of prominence research: (1) magnetic structure deduced from observations and models, (2) the dynamics of prominence plasmas (formation and flows), (3) Magneto-hydrodynamic (MHD) waves in prominences and (4) the formation and large-scale patterns of the filament channels in which prominences are located. Finally, several outstanding issues in prominence research are discussed, along with observations and models required to resolve them.Comment: 75 pages, 31 pictures, review pape

Dihydrolipoic acid reduces cytochrome b561 proteins.

Cytochrome b561 (Cyt-b561) proteins constitute a family of trans-membrane proteins that are present in a wide variety of organisms. Two of their characteristic properties are the reducibility by ascorbate (ASC) and the presence of two distinct b-type hemes localized on two opposite sides of the membrane. Here we show that the tonoplast-localized and the putative tumor suppressor Cyt-b561 proteins can be reduced by other reductants than ASC and dithionite. A detailed spectral analysis of the ASC-dependent and dihydrolipoic acid (DHLA)-dependent reduction of these two Cyt-b561 proteins is also presented. Our results are discussed in relation to the known antioxidant capability of DHLA as well as its role in the regeneration of other antioxidant compounds of cells. These results allow us to speculate on new biological functions for the trans-membrane Cyt-b561 proteins

Adverse Effects of Methylmercury: Environmental Health Research Implications

Background: The scientific discoveries of health risks resulting from methylmercury exposure began in 1865 describing ataxia, dysarthria, constriction of visual fields, impaired hearing, and sensory disturbance as symptoms of fatal methylmercury poisoning. Objective: Our aim was to examine how knowledge and consensus on methylmercury toxicity have developed in order to identify problems of wider concern in research. Data sources and extraction: We tracked key publications that reflected new insights into human methylmercury toxicity. From this evidence, we identified possible caveats of potential significance for environmental health research in general. Synthesis: At first, methylmercury research was impaired by inappropriate attention to narrow case definitions and uncertain chemical speciation. It also ignored the link between ecotoxicity and human toxicity. As a result, serious delays affected the recognition of methylmercury as a cause of serious human poisonings in Minamata, Japan. Developmental neurotoxicity was first reported in 1952, but despite accumulating evidence, the vulnerability of the developing nervous system was not taken into account in risk assessment internationally until approximately 50 years later. Imprecision in exposure assessment and other forms of uncertainty tended to cause an underestimation of methylmercury toxicity and repeatedly led to calls for more research rather than prevention. Conclusions: Coupled with legal and political rigidity that demanded convincing documentation before considering prevention and compensation, types of uncertainty that are common in environmental research delayed the scientific consensus and were used as an excuse for deferring corrective action. Symptoms of methylmercury toxicity, such as tunnel vision, forgetfulness, and lack of coordination, also seemed to affect environmental health research and its interpretation