Multi-passband Observations of a Solar Flare over the He i 10830 Å line

This study presents a C3.0 flare observed by the Big Bear Solar Observatory/Goode Solar Telescope (GST) and Interface Region Imaging Spectrograph (IRIS) on 2018 May 28 around 17:10 UT. The Near-Infrared Imaging Spectropolarimeter of GST was set to spectral imaging mode to scan five spectral positions at ±0.8, ±0.4 Å and line center of He i 10830 Å. At the flare ribbon’s leading edge, the line is observed to undergo enhanced absorption, while the rest of the ribbon is observed to be in emission. When in emission, the contrast compared to the preflare ranges from about 30% to nearly 100% at different spectral positions. Two types of spectra, “convex” shape with higher intensity at line core and “concave” shape with higher emission in the line wings, are found at the trailing and peak flaring areas, respectively. On the ribbon front, negative contrasts, or enhanced absorption, of about ∼10%–20% appear in all five wavelengths. This observation strongly suggests that the negative flares observed in He i 10830 Å with mono-filtergram previously were not caused by pure Doppler shifts of this spectral line. Instead, the enhanced absorption appears to be a consequence of flare-energy injection, namely nonthermal collisional ionization of helium caused by the precipitation of high-energy electrons, as found in our recent numerical modeling results. In addition, though not strictly simultaneous, observations of Mg ii from the IRIS spacecraft, show an obvious central reversal pattern at the locations where enhanced absorption of He i 10830 Å is seen, which is consistent with previous observations.

Continuous temperature soundings at the stratosphere and lower mesosphere with a ground-based radiometer considering the Zeeman effect

Continuous temperature observations at the stratosphere and lower mesosphere are rare. Radiometry opens the possibility by observing microwave emissions from two oxygen lines to retrieve temperature profiles at all altitudes. In this study, we present observations performed with a temperature radiometer (TEMPERA) at the Meteoswiss station at Payerne for the period from 2014 to 2017. We reanalyzed these observations with a recently developed and improved retrieval algorithm accounting for the Zeeman line splitting in the line center of both oxygen emission lines at 52.5424 and 53.0669 GHz. The new temperature retrievals were validated against MERRA2 reanalysis and the meteorological analysis NAVGEM-HA. The comparison confirmed that the new algorithm yields an increased measurement response up to an altitude of 53–55 km, which extends the altitude coverage by 8–10 km compared to previous retrievals without considering the Zeeman effect. Furthermore, we found correlation coefficients comparing the TEMPERA temperatures with MERRA2 and NAVGEM-HA for monthly mean profiles to be in the range of 0.8–0.96. In addition, mean temperature biases of 1 K and −2 K were found between TEMPERA and both models (MERRA2 and NAVGEM-HA), respectively. We also identified systematic altitude-dependent cold and warm biases compared to both model data sets.

A Supersensitive Method for Spectroscopic Diagnostics of Electrostatic Waves in Magnetized Plasmas

For relatively strong magnetic fields, hydrogen atoms can have delocalized bound states of almost macroscopic dimensions. Therefore, such states are characterized by a Giant Electric Dipole Moment (GEDM), thus making them very sensitive to an external electric field. We considered the manifestations of the GEDM states in hydrogen spectral line profiles in the presence of a quasimonochromatic electrostatic wave of a frequency ω in a plasma. We demonstrated that in this situation, hydrogen spectral lines can exhibit quasi-satellites, which are the envelopes of Blochinzew-type satellites. We showed that the distinctive feature of such quasi-satellites is that their peak intensity is located at the same distance from the line center (in the frequency scale) for all hydrogen spectral lines, the distance being significantly greater than the wave frequency ω. At the absence of the GEDM (and for relatively strong electrostatic waves), the maxima of the satellite envelopes would be at different distances from the line center for different hydrogen lines. We demonstrated that this effect would constitute a supersensitive diagnostic method for measuring the amplitude of electrostatic waves in plasmas down to ~10 V/cm or even lower.

Lamb-dip cavity ring-down spectroscopy of acetylene at 1.4 μm

Doppler-free saturated-absorption Lamb dips are observed for weak vibration-rotation transitions of C2H2 between 7167 and 7217 cm−1, using a frequencycomb assisted cavity ring-down spectrometer based on the use of a pair of phase-locked diode lasers. We measured the absolute center frequency of sixteen lines belonging to the 2ν3 + ν15 band, targeting ortho and para states of the molecule. Line pairs of the P and Q branches were selected so as to form a “V”-scheme, sharing the lower energy level. Such a choice made it possible to determine the rotational energy separations of the excited vibrational state for J-values from 11 to 20. Line-center frequencies are determined with an overall uncertainty between 2 and 13 kHz. This is over three order of magnitude more accurate than previous experimental studies in the spectral region around the wavelength of 1.4 μm. The retrieved energy separations provide a stringent test of the so-called MARVEL method recently applied to acetylene.

Heartburn Center Set-Up in a Community Setting: Engineering and Execution

Background: Optimal management of gastroesophageal reflux disease (GERD) requires a concerted team of physicians rather than an individual approach. While an integrated approach to GERD has previously been proposed, the practical execution of such a “center of excellence” (COE) has not been described, particularly in a community setting. Ranging from initial consultation and diagnosis to surgical intervention for complex disease, such an approach is likely to provide optimal care and provide surveillance for patients with a complex disease process of GERD.Methods: We report our approach to implement an integrated heartburn center (HBC) and our experience with the first cohort of patients. Patients treated in the HBC were followed for 2 years from initial consultation to completion of their appropriate treatment plan, including anti-reflux surgery. The performance prior to the HBC set-up was compared to that post-HBC. Performance was measured in terms of volume of patients referred, referral patterns, length of stay (LOS), and patient health-related quality of life (HRQL) pre- and post-surgery.Results: Setting up the HBC resulted in referrals from multiple avenues, including primary care physicians (PCPs), emergency departments (EDs), and gastroenterologists (GIs). There was a 75% increase in referrals compared to pre-center patient volumes. Among the initial cohort of 832 patients presenting to the HBC, <10% had GERD for <1 year, ~60% had GERD for 1–11 years, and ~30% had GERD for ≥12 years. More than one-quarter had atypical GERD symptoms (27.6%). Only 6.4% had been on PPIs for <1 year and >20% had been on PPIs for ≥12 years. Thirty-eight patients were found to have Barrett's esophagus (4.6%) (up to 10 times the general population prevalence). Two patients had dysplasia. Seven patients (0.8%) received radiofrequency ablation (RFA) for Barrett's esophagus and two patients received endoscopic mucosal resection (EMR) for Barrett's esophagus-related dysplasia. The most common comorbidities were chronic pulmonary disease (16.8%) and diabetes without complications (10.6%). Patients received treatment for newly identified comorbid conditions, including early maladaptive schemas (EMS) and generalized anxiety disorder (GAD) (n = 7; 0.8%). Fifty cases required consultation with various specialists (6.0%) and 34 of those (4.1%) resulted in changes in care. Despite the significant increase in patient referrals, conversion rates from diagnosis to anti-reflux surgery remained consistent at ~25%. Overall HRQL improved year-over-year, and LOS was significantly reduced with potential cost savings for the larger institution.Conclusions: While centralization of GERD care is known to improve outcomes, in this case study we demonstrated the clinical success and commercial viability of centralizing GERD care in a community setting. The integrated GERD service line center offered a comprehensive, multi-specialty, and coordinated patient-centered approach. The approach is reproducible and may allow hospitals to set up their own heartburn COEs, strengthening patient-community relationships and establishing scientific and clinical GERD leadership.

Spaceborne differential absorption radar water vapor retrieval capabilities in tropical and subtropical boundary layer cloud regimes

Differential absorption radar (DAR) near the 183 GHz water vapor absorption line is an emerging measurement technique for humidity profiling inside of clouds and precipitation with high vertical resolution, as well as for measuring integrated water vapor (IWV) in clear-air regions. For radar transmit frequencies on the water line flank away from the highly attenuating line center, the DAR system becomes most sensitive to water vapor in the planetary boundary layer (PBL), which is a region of the atmosphere that is poorly resolved in the vertical by existing spaceborne humidity and temperature profiling instruments. In this work, we present a high-fidelity, end-to-end simulation framework for notional spaceborne DAR instruments that feature realistically achievable radar performance metrics and apply this simulator to assess DAR's PBL humidity observation capabilities. Both the assumed instrument parameters and radar retrieval algorithm leverage recent technology and algorithm development for an existing airborne DAR instrument. To showcase the capabilities of DAR for humidity observations in a variety of relevant PBL settings, we implement the instrument simulator in the context of large eddy simulations (LESs) of five different cloud regimes throughout the trade-wind subtropical-to-tropical cloud transition. Three distinct DAR humidity observations are investigated: IWV between the top of the atmosphere and the first detected cloud bin or Earth's surface; in-cloud water vapor profiles with 200 meter vertical resolution; and IWV between the last detected cloud bin and the Earth's surface, which can provide a precise measurement of the sub-cloud humidity. We provide a thorough assessment of the systematic and random errors for all three measurement products for each LES case and analyze the humidity precision scaling with along-track measurement integration. While retrieval performance depends greatly on the specific cloud regime, we find generally that for a radar with cross-track scanning capability, in-cloud profiles with 200 m vertical resolution and 10 %–20 % uncertainty can be retrieved for horizontal integration distances of 100–200 km. Furthermore, column IWV can be retrieved with 10 % uncertainty for 10–20 km of horizontal integration. Finally, we provide some example science applications of the simulated DAR observations, including estimating near-surface relative humidity using the cloud-to-surface column IWV and inferring in-cloud temperature profiles from the DAR water vapor profiles by assuming a fully saturated environment.

COMPARISON OF AS, HG AND TL HIGH-FREQUENCY ELECTRODELESS LAMPS FOR DETECTION OF ENVIRONMENTAL POLLUTION

Nowadays, there is an increasing necessity to determine the concentration of different substances in the environment in low concentrations, as more and more attention is paid to environmental pollution. This work is devoted to the comparison of main characteristics of high-frequency electrodeless light sources with different fillings for their use in high precision atomic absorption analysers.The spectral line intensities and profiles were studied in special design light sources, manufactured at Institute of Atomic Physics and Spectroscopy, with arsenic, mercury and thallium filling. Special attention is devoted to the UV lines of 193.7 nm and 197.2 nm of As, 276.8 nm, 377.6 nm of Tl and 253.7 nm of Hg spectral lines. The intensities and profiles were measured by means of a Fourier transform spectrometer.The deconvolution procedure was implemented to obtain the real form of emitted profiles for further analysis, since in the case of low –pressure or cold plasma, the instrumental function is on the same order that experimental profile and it has to be taken into account. The instrumental function can distort the real spectral line shape significantly, for example, it changes the width of the spectral line that leads to the uncertainties in the determination of such important plasma parameters like temperature. The instrumental function can conceal a detailed structure of the spectral line, like the dip in the line center caused by the self-absorption (self-reversal) and characterizing the radiation trapping.The integrated areas, values of self-absorption, and other parameters were obtained and compared for all fillings as a function of working regimes.

Electrical Resistance Reduction Induced with CO2 Laser Single Line Scan of Polyimide

We conducted a laser parameter study on CO2 laser induced electrical conductivity on a polyimide film. The induced electrical conductivity was found to occur dominantly at the center of the scanning line instead of uniformly across the whole line width. MicroRaman examination revealed that the conductivity was mainly a result of the multi-layers (4–5) of graphene structure induced at the laser irradiation line center. The graphene morphology at the line center appeared as thin wall porous structures together with nano level fiber structures. With sufficient energy dose per unit length and laser power, this surface modification for electrical conductivity was independent of laser pulse frequency but was instead determined by the average laser power. High electrical conductivity could be achieved by a single scan of laser beam at a sufficiently high-power level. To achieve high conductivity, it was not efficient nor effective to utilize a laser at low power but compensating it with a slower scanning speed or having multiple scans. The electrical resistance over a 10 mm scanned length decreased significantly from a few hundred Ohms to 30 Ohms when energy dose per unit length increased from 0.16 J/mm to 1.0 J/mm, i.e., the laser power increased from 5.0 W to 24 W with corresponding power density of 3.44 × 10 W/cm2 to 16.54 W/cm2 respectively at a speed of 12.5 mm/s for a single pass scan. In contrast, power below 5 W at speeds exceeding 22.5 mm/s resulted in a non-conductive open loop.

No Evidence of Perceptual Pseudoneglect in Alexithymia

The research in neuroscience links alexithymia, the difficulty of identifying and describing feelings and emotions, with a left hemisphere preference and/or a right hemisphere deficit. To provide a neuropsychological support to this finding, we explored the relationship between alexithymia and the performance in a line bisection task, a standard method to evaluate spatial attention in relation with the functioning of the right hemisphere. 222 healthy participants completed a version of the TAS-20 scale, which measures alexithymia, and were asked to mark (bisect) the center of a 10 cm horizontal segment. The results document a significant rightward shift of the line center in borderline and manifest alexithymic participants, as compared to non-alexithymic individuals. Moreover, the higher the TAS-20 score the greater the rightward shift in the line bisection task. This result supports the right-hemisphere deficit hypothesis in alexithymia and suggests that visuospatial abnormalities may be an inner component of their profile.