On-Orbit Performance of the Helioseismic and Magnetic Imager Instrument onboard the Solar Dynamics Observatory

The Helioseismic and Magnetic Imager (HMI) instrument is a major component of NASA's Solar Dynamics Observatory (SDO) spacecraft. Since commencement of full regular science operations on 1 May 2010, HMI has operated with remarkable continuity, e.g. during the more than five years of the SDO prime mission that ended 30 September 2015, HMI collected 98.4% of all possible 45-second velocity maps; minimizing gaps in these full-disk Dopplergrams is crucial for helioseismology. HMI velocity, intensity, and magnetic-field measurements are used in numerous investigations, so understanding the quality of the data is important. This article describes the calibration measurements used to track the performance of the HMI instrument, and it details trends in important instrument parameters during the prime mission. Regular calibration sequences provide information used to improve and update the calibration of HMI data. The set-point temperature of the instrument front window and optical bench is adjusted regularly to maintain instrument focus, and changes in the temperature-control scheme have been made to improve stability in the observable quantities. The exposure time has been changed to compensate for a 20% decrease in instrument throughput. Measurements of the performance of the shutter and tuning mechanisms show that they are aging as expected and continue to perform according to specification. Parameters of the tunable optical-filter elements are regularly adjusted to account for drifts in the central wavelength. Frequent measurements of changing CCD-camera characteristics, such as gain and flat field, are used to calibrate the observations. Infrequent expected events such as eclipses, transits, and spacecraft off-points interrupt regular instrument operations and provide the opportunity to perform additional calibration. Onboard instrument anomalies are rare and seem to occur quite uniformly in time. The instrument continues to perform very well.

Synthesis of ligand-free CZTS nanoparticles via a facile hot injection route

Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.

Femtosecond-laser ablation dynamics of dielectrics: basics and applications for thin films

Laser ablation of dielectrics by ultrashort laser pulses is reviewed. The basic interaction between ultrashort light pulses and the dielectric material is described, and different approaches to the modeling of the femtosecond ablation dynamics are reviewed. Material excitation by ultrashort laser pulses is induced by a combination of strong-field excitation (multi-photon and tunnel excitation), collisional excitation (potentially leading to an avalanche process), and absorption in the plasma consisting of the electrons excited to the conduction band. It is discussed how these excitation processes can be described by various rate-equation models in combination with different descriptions of the excited electrons. The optical properties of the highly excited dielectric undergo a rapid change during the laser pulse, which must be included in a detailed modeling of the excitations. The material ejected from the dielectric following the femtosecond-laser excitation can potentially be used for thin-film deposition. The deposition rate is typically much smaller than that for nanosecond lasers, but film production by femtosecond lasers does possess several attractive features. First, the strong-field excitation makes it possible to produce films of materials that are transparent to the laser light. Second, the highly localized excitation reduces the emission of larger material particulates. Third, lasers with ultrashort pulses are shown to be particularly useful tools for the production of nanocluster films. The important question of the film stoichiometry relative to that of the target will be thoroughly discussed in relation to the films reported in the literature.

Wave-like properties of solar supergranulation

Supergranulation on the surface of the Sun is a pattern of horizontal outflows, outlined by a network of small magnetic features, with a distinct scale of 30 million metres and an apparent lifetime of one day. It is generally believed that supergranulation corresponds to a preferred 'cellular' scale of thermal convection; rising magnetic fields are dragged by the outflows and concentrated into 'ropes' at the 'cell' boundaries. But as the convection zone is highly turbulent and stratified, numerical modelling has proved to be difficult and the dynamics remain poorly understood. Moreover, there is as yet no explanation for the observation that the pattern appears to rotate faster around the Sun than the magnetic features. Here we report observations showing that supergranulation undergoes oscillations and supports waves with periods of 6-9 days. The waves are predominantly prograde, which explains the apparent super-rotation of the pattern. The rotation of the plasma through which the pattern propagates is consistent with the motion of the magnetic network.

Helioseismic measurement of solar torsional oscillations

Bands of slower and faster rotation, the so-called torsional oscillations, are observed at the Sun's surface to migrate in latitude over the 11-year solar cycle. Here, we report on the temporal variations of the Sun's internal rotation from solar p-mode frequencies obtained over nearly 6 years by the Michelson Doppler Imager (MDI) instrument on board the Solar and Heliospheric Observatory (SOHO) satellite. The entire solar convective envelope appears to be involved in the torsional oscillations, with phase propagating poleward and equatorward from midlatitudes at all depths throughout the convective envelope.

In search of the most suitable technique for truncal spinal immobilization with associated radiography

The spineboard (SB) and the vacuum mattress (VM) are utilized for prehospital and emergency department (ED) immobilization of the spine. While permitting excellent pictures to be taken, the SB is a very painful device that can only be used for a limited time. The current study investigated the feasibility of different models of the VM for radiography. Computed tomography for each of seven VMs showed different degrees of shadows from the sac containing the polystyrole balls. This was related first of all to a high contrast of the sac in comparison with its contents and to a sometimes considerable shrinkage of the latter that resulted in further folding into the sac and, secondly, also to very broad mattresses, additional chambers within the VM and various grips and supports for lifting the mattress. Therefore, some features designed for prehospital use of the VM are actually acting against its use for diagnostic purposes. The aim of this study was to discuss and identify possible properties of a device that is useful for both immobilization and diagnostic purposes.

Changes in sexual behavior after orthopedic replacement of hip or knee in elderly males--a prospective study

The aim of this study was to investigate two questions: Does arthroplastic surgery affect the patient's status as being sexually active; and if patients are sexually active, does surgery affect their erectile function? The study was designed prospectively and the patients filled in a questionnaire concerning sexuality and erectile function before and 6 months after alloplastic hip-or knee surgery. Ninety-nine males were included, mean age 70.6 y. The results demonstrate that 17% of patients lost a sexual activity that they had preoperatively, and no one regained sexual activity after surgery. A correlation between increasing age and risk of losing sexual activity was demonstrated. 26.1% lost a normal erectile function they had preoperatively, while 6.7% regained normal erections. A similar correlation between increasing age and increased risk was demonstrated. From this study of elderly males undergoing orthopaedic alloplastic surgery it is concluded that the risk of losing sexual activity and erectile capability is increased after surgery, and especially in the group where sexual functions are already impaired.

Angular distribution of electron temperature and density in a laser-ablation plume

The angular distribution of electron temperature and density in a laser-ablation plume has been studied for the first time. The electron temperature ranges from 0.1 to 0.5 eV and is only weakly dependent on the angle in the low-intensity range studied here. In contrast, the typical ion energy is about 2 orders of magnitude larger, and its angular distribution is more peaked about the target normal. The derived values of the electron density are in agreement with the measured values of ion density.

Deeply Penetrating Banded Zonal Flows in the Solar Convection Zone

Helioseismic observations have detected small temporal variations of the rotation rate below the solar surface that correspond to the so-called "torsional oscillations" known from Doppler measurements of the surface. These appear as bands of slower- and faster-than-average rotation moving equatorward. Here we establish, using complementary helioseismic observations over 4 yr from the GONG network and from the MDI instrument on board SOHO, that the banded flows are not merely a near-surface phenomenon: rather, they extend downward at least 60 Mm (some 8% of the total solar radius) and thus are evident over a significant fraction of the nearly 200 Mm depth of the solar convection zone.

Dynamic variations at the base of the solar convection zone

We have detected changes in the rotation of the sun near the base of its convective envelope, including a prominent variation with a period of 1.3 years at low latitudes. Such helioseismic probing of the deep solar interior has been enabled by nearly continuous observation of its oscillation modes with two complementary experiments. Inversion of the global-mode frequency splittings reveals that the largest temporal changes in the angular velocity Omega are of the order of 6 nanohertz and occur above and below the tachocline that separates the sun's differentially rotating convection zone (outer 30% by radius) from the nearly uniformly rotating deeper radiative interior beneath. Such changes are most pronounced near the equator and at high latitudes and are a substantial fraction of the average 30-nanohertz difference in Omega with radius across the tachocline at the equator. The results indicate variations of rotation close to the presumed site of the solar dynamo, which may generate the 22-year cycles of magnetic activity.

Abdominal haemorrhage--a preventable cause of death after field stabilization?

The causes of preventable death vary in different operational settings, and the topic has not previously been explored in a fully developed central European rescue system. The factors associated with potentially preventable death were studied in a retrospective study of 430 fatal traffic accident victims (1980-96) in Lörrach County, Germany. Mission protocols could be retrieved for detailed analysis in 239 of the cases. These were studied in order to identify factors associated with preventable death. At the scene of the accident, 38% of the patients died without cardiopulmonary resuscitation (CPR) and 18% after CPR. Four patients died after a certain delay without CPR before reaching hospital. A total of 43% of the victims were admitted to hospital, 5% had received prehospital CPR and the remaining 38% had not. In a subgroup representing the experience of a single emergency physician 60 fatalities were studied. Of these, 27 (45%) patients died within the hospital; almost half of these cases (13/27) had been conscious at some time after the accident and of these, seven (7/13) died from intra-abdominal bleeding within 4 h after admission. The same cause of death was found in 3 of the 14 comatose patients. Pleural drainage was carried out in four patients and unrecognized pneumothoraces or spinal injuries did not occur. Tracheal intubation was employed in 24/27. Medical antishock trousers (MAST) were not available. The data indicate that intra-abdominal haemorrhage is an underestimated cause of death in a comprehensive rescue system, possibly as a consequence of field stabilization. The use of MAST may be a relevant therapeutic option to prevent these fatalities. The method offers the possibility of intra-abdominal compression and haemostasis after tracheal intubation has been performed. Previous controlled studies on MAST may have been biased by faulty methodology (e.g. absence of tracheal intubation) and inappropriate indications (e.g. other causes of shock). The value of MAST in comprehensive rescue systems should therefore be reassessed. The difficulties in identifying factors leading to preventable death in a retrospective analysis, are discussed and it is recommended that a permanent prospective quality control be performed in all cases of fatal accidents in order to ensure the continued improvement of prehospital emergency medical systems.

Interstitial cystitis provoked by tiaprofenic acid

A patient developed clinical and histological interstitial cystitis as an adverse effect of treatment with tiaprofenic acid for rheumatism. After cessation of the drug, full symptomatic recovery was obtained. Bladder biopsies 6 months later demonstrated normalization of detrusor muscle histology.

Delayed mobilization of the emergency physician in prehospital missions

A retrospective analysis of 118 prehospital missions involving vitally important therapy (anaesthesia or resuscitation with admission) was carried out. Primary mobilization of the emergency physician (EP) (i.e. before arrival of the rescue ambulance) was carried out by the alarm dispatch centre in only 36% of these missions. In the 74 missions utilizing secondary alarm (i.e. request for the EP after the arrival of the ambulance), detrimental delay of 8 minutes or more was found in 30%. In two of the 27 missions of cardiopulmonary resuscitation with subsequent admission, the physician was only mobilized after the patient developed cardiac arrest during unescorted transport although acute myocardial infarction had been suspected prior to transport. The observations suggest that an improved assessment of possible involvement of an EP is necessary, both at the alarm central and the emergency site. Moreover, continued monitoring (quality control) of this delay is necessary.

Duration and type of prehospital emergency therapy

Prehospital on-scene time (OST) has only been recorded sporadically and has not been related to different types of therapy. In order to create a reference standard for a European emergency medical system involving field stabilization (FS) by physicians, a retrospective analysis was performed of 639 consecutive missions over 81 months in relation to the extent of therapy evaluated by the Emergency Therapy Index (ETI). An OST was not registered in ETI-0-2. The median OST in ETI-3 was 14.0 minutes, slightly increasing with mission grade to 19.5 minutes in ETI-6, and then suddenly increasing to 23.5 minutes in cases of intubation (ETI-7) and to 26.0 minutes when cardiopulmonary resuscitation was performed with subsequent admission (ETI-8). A variety of prehospital therapy is demonstrated. The study supports the view that only exceptional conditions can justify an OST exceeding 20 minutes in ETI-3-4, 24 minutes in ETI-5-6 and 33 minutes in ETI-7.

Use of Image-Processing Tools for Texture Analysis of High-Energy X-ray Synchrotron Data

The introduction of synchrotron beamlines for high-energy X-ray diffraction raises new possibilities for texture determination of polycrystalline materials. The local texture can be mapped out in three dimensions and texture developments can be studiedin situin complicated environments. However, it is found that a full alignment of the two-dimensional detector used in many cases is impractical and that data-sets are often partially subject to geometric restrictions. Estimating the parameters of the traces of the Debye–Scherrer cones on the detector therefore becomes a concern. Moreover, the background may vary substantially on a local scale as a result of inhomogeneities in the sample environmentetc. A set of image-processing tools has been employed to overcome these complications. An automatic procedure for estimating the parameters of the traces (taken as ellipses) is described, based on a combination of a circular Hough transform and nonlinear least-squares fitting. Using the estimated ellipses the background is subtracted and the intensity along the Debye–Scherrer cones is integrated by a combined fit of the local diffraction pattern. The corresponding algorithms are presented together with the necessary coordinate transform for pole-figure determination. The image-processing tools may be useful for the analysis of noisy or partial powder diffraction data-sets in general, provided flat two-dimensional detectors are used.

Use of non-pneumatic antishock garments for ruptured abdominal aortic aneurysm

Two cases of near-fatal aortic abdominal aneurysm (AAA) are described which were successfully stabilized by a new principle for exerting abdominal compression, the non-pneumatic medical antishock trousers (NP-MAST). Obviously, the compression obtained with the NP-MAST suffices for this dramatic emergency. Moreover, compared with pneumatic antishock garments (PASG), the NP-MAST has the advantage of being light, independent of flight height and unable to produce dangerously high pressures. Moreover, it contains no manometers, which could detract the doctor's attention from more important measures. The need for endotracheal intubation in advance to application of any kind of abdominal compression (PASG or NP-MAST) is stressed.

[Validation of the patient-administered Danish Prostate Symptom Score Schedule]

The DAN-PSS-1 system, a self-administered quality-of-life questionnaire comprising 12 questions related to voiding problems and the perceived bother of each individual symptom, was compared to other extensively used score systems and furthermore included in different clinical situations so as to validate the system. The system was internally consistent (alpha cr = 0.73), the median test-retest reliability of answers to each question was 83.5% (range 0-99.7%). A high degree of construct validity demonstrated in the correlation with the Madsen-Iversen score system (rs = 0.51) and with the patients' answers to questions about how bothersome their symptoms were (rs = 0.71). The discriminant validity of the DAN-PSS-1 was excellent with an area under the ROC curve of 0.94. Finally, the DAN-PSS-1 was sensitive to changes following intervention, with scores decreasing 100% after transurethral prostatectomy and 65% after four months of treatment with an alpha-blocker. The DAN-PSS-1 is reliable, valid and responsive, and therefore can be recommended for assessing the severity of symptoms among patients presenting with lower urinary tract complaints suggestive of BPH and during follow-up.

Major interventions in the field stabilization of trauma patients: what is possible?

Previous studies on prehospital care are mostly hampered by a large number of less-urgent missions and lack of utilization of the possibilities which blur the effect of an advanced medical service. The current analysis of the most aggressive trauma care on-scene concludes that largely all vital stabilization can be carried out prehospitally, except performing an X-ray (with its possible consequences) and an operation. The latter measure does, however, also represent the current limits of field stabilization: circulatory unstable patients with penetrating bleeding trauma or presumed internal haemorrhagia will require a minimal stabilization--concentrating on securing the airway--and then fast transport to the nearest hospital with capability to carry out an acute operation (the 'scoop and run' principle). Novel principles and pathophysiological understanding indicate that new principles of field stabilization may actually offer further support and thereby increase the chances of survival for these patients, provided the necessary new techniques acknowledge the need for speed. In this development, the principles in prehospital care often exceeds what is actually offered in the hospitals' emergency rooms. Since the majority of advanced prehospital methods depends on comparatively safe anaesthesia and analgesia techniques, the particular responsibility for anaesthetists in this field is stressed.

Differential Rotation and Dynamics of the Solar Interior

Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes.

The Solar Acoustic Spectrum and Eigenmode Parameters

The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.

Omeprazole and visual disorders: seeing alternatives

In the WHO data base, visual disorders reported spontaneously with omeprazole, ranitidine and cimetidine, are very rare in the context of the widespread use of these drugs. There is a maximum reporting rate of severe visual impairment possibly ascribed to i.v. omeprazole of 0.94 reports per million treatment days in one year and in one country, Germany. This gives the worst quantitative case scenario for omeprazole by a single route of administration, to be compared with the worldwide reporting rate of all severe visual disorders by all routes of administration--0.008 reports per million treatment days. Moreover, the reported visual abnormalities have a varied pathophysiological aetiology and their number increased in Germany after the first signal was raised in that country. Thus, apart from a direct causal relationship, solicited reporting artifact is one alternate plausible explanation for the apparent excess of cases of visual disturbance to omeprazole compared with cimetidine and ranitidine. That reporting rates of clinical events on newly marketed drugs are generally higher than with older drugs is a second factor for higher reporting rates with omeprazole. Vasculitis has been suggested as an aetiological factor, but the even lower reporting rate of this reaction makes this an unlikely hypothesis without any other supporting evidence. The authors are unaware of any drug that has caused a vasculities solely affecting the eye. Information on the prevalence of relevant visual disorders in the community would have been of considerable help in interpreting this signal, and a case control study of visual events in relationship to severe illness would be of public health interest, since no data seems to exist concerning this.