A multi-chord, two-color interferometer using Hilbert transform phase detection for measuring electron density in spheromak plasmas.

A new, four-chord, CO2/He-Ne heterodyne interferometer has been designed and built for measuring line-averaged plasma density in the HIT-SI3 and subsequent HIT-SIU sustained spheromak devices. The two-color system successfully eliminates vibration-induced errors caused by mirrors that are secured to the vacuum chamber and is able to resolve electron densities ne in the full operating range of 1018-1020 m-3 in both experiments with an integrated error of 4.7 × 1017 m-2. Data are presented from high toroidal current plasma discharges, showing the time evolution of electron densities ne and jϕ/ne along multiple chords.

Juno's Close Encounter With Ganymede-An Overview.

The Juno spacecraft has been in orbit around Jupiter since 2016. Two flybys of Ganymede were executed in 2021, opportunities realized by evolution of Juno's polar orbit over the intervening 5 years. The geometry of the close flyby just prior to the 34th perijove pass by Jupiter brought the spacecraft inside Ganymede's unique magnetosphere. Juno's payload, designed to study Jupiter's magnetosphere, had ample dynamic range to study Ganymede's magnetosphere. The Juno radio system was used both for gravity measurements and for study of Ganymede's ionosphere. Remote sensing of Ganymede returned new results on geology, surface composition, and thermal properties of the surface and subsurface.

Ganymede Observations by JunoCam on Juno Perijove 34.

During the Juno Mission's encounter with Ganymede on 7 June 2021, the Juno camera (JunoCam) acquired four images of Ganymede in color. These images covered one-sixth of Ganymede at scales from 840 m to ∼4 km/pixel. Most of this area was only previously imaged by Voyager 1 in 1979, at lower spatial resolution and poorer image quality. No changes were observed over this area of Ganymede in the 42 years since Voyager. JunoCam provided overlapping coverage, from which we developed a digital elevation model of the best-resolved area. A 3 km high dome at the subjovian point was confirmed, 450 km by 750 km. We used the JunoCam images to refine the geologic map of Ganymede in eastern Perrine Regio.

High-speed feedback control of an oscillating magnetic helicity injector using a graphics processing unit.

A real-time control system has been developed to control the amplitude, phase, and offset of bulk plasma parameters inside an oscillating magnetic helicity injector. Control software running entirely on an Nvidia Tesla P40 graphical processing unit is able to receive digitizer inputs and send response patterns to a Pulse Width Modulation (PWM) controller with a minimum control loop period of 12.8 µs. With an input digitization rate of 10 MS/s, a three-parameter proportional integral differential controller is shown to be sufficient to inform the PWM controller to drive the desired oscillating plasma waveform with a frequency of 16.6 kHz that is located near the resonance of a coupled RLC circuit. In particular, the temporal phase of the injector waveform is held within 10° of the target value. Control is demonstrated over the toroidal modal structure of the imposed magnetic perturbations of the helicity injection system, allowing a new class of discharges to be studied.

Predicting mortality with applied machine learning: Can we get there?

There is growing interest in using AI-based algorithms to support clinician decision-making. An important consideration is how transparent complex algorithms can be for predictions, particularly with respect to imminent mortality in a hospital environment. Understanding the basis of predictions, the process used to generate models and recommendations, how to generalize models based on one patient population to another, and the role of oversight organizations such as the Food and Drug Administration are important topics. In this paper, we debate opposing positions regarding whether these algorithms are 'ready yet' for use today in clinical settings for physicians, patients and caregivers. We report voting results from participating audience members in attendance at the conference debate for each of these positions obtained real-time from a smartphone-based platform.

Evidence for separatrix formation and sustainment with steady inductive helicity injection.

The first sustainment of toroidal plasma current of 50 kA at up to 3 times the injected currents, added in quadrature, using steady inductive helicity injection is described. Separatrix currents-currents not linking the helicity injectors-are sustained up to 40 kA. Decreases in the n=1 toroidal mode of the poloidal magnetic field at higher current amplifications indicate more quiescent, direct toroidal current drive. Results are achieved in HIT-SI (with a spheromak of major radius 0.3 m) during deuterium operations immediately after helium operation. These results represent a breakthrough in the development of this new current drive method for magnetic confinement fusion.

Seasonal erosion and restoration of Mars' northern polar dunes.

Despite radically different environmental conditions, terrestrial and martian dunes bear a strong resemblance, indicating that the basic processes of saltation and grainfall (sand avalanching down the dune slipface) operate on both worlds. Here, we show that martian dunes are subject to an additional modification process not found on Earth: springtime sublimation of Mars' CO(2) seasonal polar caps. Numerous dunes in Mars' north polar region have experienced morphological changes within a Mars year, detected in images acquired by the High-Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter. Dunes show new alcoves, gullies, and dune apron extension. This is followed by remobilization of the fresh deposits by the wind, forming ripples and erasing gullies. The widespread nature of these rapid changes, and the pristine appearance of most dunes in the area, implicates active sand transport in the vast polar erg in Mars' current climate.

Adenovirus 36 seropositivity is strongly associated with race and gender, but not obesity, among US military personnel.

BACKGROUND: Although several studies have shown a positive association between evidence of anti-adenovirus 36 (Ad-36) antibodies (Ad-36 exposure) and (1) obesity and (2) serum cholesterol in animals, there is limited research demonstrating this association in humans. There is also limited research on transmission, presentation and demographics of Ad-36 infection. DESIGN: (1) Body mass (body mass index (BMI)), (2) fasting serum cholesterol and triglyceride levels and (3) demographic characteristics were compared between Ad-36 seropositive and seronegative groups. The majority of subjects were matched as cases versus controls on a number of demographic variables. SUBJECTS: A total of 150 obese and 150 lean active-duty military personnel were studied. MEASUREMENTS: Subjects completed a questionnaire regarding demographic and behavioral characteristics. Subject serum samples were tested by serum neutralization assay for the presence of anti-Ad-36 antibodies. RESULTS: In all, 34% of obese and 39% of lean subjects had Ad-36 exposure, an insignificant difference. Serum cholesterol and triglyceride levels were significantly higher among the obese subjects than among the lean, but there were no associations between serum cholesterol and triglyceride levels and Ad-36 exposure. Positive associations were found between Ad-36 exposure and age, race and gender. CONCLUSION: The study stands in contrast to previous work that has shown a positive relationship between Ad-36 exposure and (1) obesity, and (2) levels of serum cholesterol and triglycerides. In this study there was no association in either case. Unanticipated relationships between Ad-36 exposure and age, race and gender were found, and this is the first time that such a link between Ad-36 exposure and demographics has been found.

Water vapour jets inside the plume of gas leaving Enceladus.

A plume of water vapour escapes from fissures crossing the south polar region of the Saturnian moon Enceladus. Tidal deformation of a thin surface crust above an internal ocean could result in tensile and compressive stresses that would affect the width of the fissures; therefore, the quantity of water vapour released at different locations in Enceladus' eccentric orbit is a crucial measurement of tidal control of venting. Here we report observations of an occultation of a star by the plume on 24 October 2007 that revealed four high-density gas jets superimposed on the background plume. The gas jet positions coincide with those of dust jets reported elsewhere inside the plume. The maximum water column density in the plume is about twice the density reported earlier. The density ratio does not agree with predictions-we should have seen less water than was observed in 2005. The ratio of the jets' bulk vertical velocities to their thermal velocities is 1.5 +/- 0.2, which supports the hypothesis that the source of the plume is liquid water, with gas accelerated to supersonic velocity in nozzle-like channels.

The dust halo of Saturn's largest icy moon, Rhea.

Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete rings or arcs of material.

A closer look at water-related geologic activity on Mars.

Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to approximately 2 meters in diameter are ubiquitous in the middle to high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright gully deposits identify six locations with very recent activity, but these lie on steep (20 degrees to 35 degrees) slopes where dry mass wasting could occur. Thus, we cannot confirm the reality of ancient oceans or water in active gullies but do see evidence of fluvial modification of geologically recent mid-latitude gullies and equatorial impact craters.

Development of a novel continuous culture device for experimental evolution of bacterial populations.

The availability of a robust and reliable continuous culture apparatus that eliminates wall growth problems would lead to many applications in the microbial field, including allowing genetically engineered strains to recover high fitness, improving biodegradation strains, and predicting likely antibiotic resistance mechanisms. We describe the design and implementation of a novel automated continuous culture machine that can be used both in time-dependent mode (similar to a chemostat) and turbidostat modes, in which wall growth is circumvented through the use of a long, variably divisible tube of growth medium. This tube can be restricted with clamps to create a mobile growth chamber region in which static portions of the tube and the associated medium are replaced together at equal rates. To functionally test the device as a tool for re-adaptation of engineered strains, we evolved a strain carrying a highly deleterious deletion of Elongation Factor P, a gene involved in translation. In 200 generations over 2 weeks of dilution cycles, the evolved strain improved in generation time by a factor of three, with no contaminations and easy manipulation.

Surface composition of Hyperion.

Hyperion, Saturn's eighth largest icy satellite, is a body of irregular shape in a state of chaotic rotation. The surface is segregated into two distinct units. A spatially dominant high-albedo unit having the strong signature of H2O ice contrasts with a unit that is about a factor of four lower in albedo and is found mostly in the bottoms of cup-like craters. Here we report observations of Hyperion's surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft at closest approach during a fly-by on 25-26 September 2005. The close fly-by afforded us the opportunity to obtain separate reflectance spectra of the high- and low-albedo surface components. The low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe and a hemisphere-wide superficial coating on Iapetus.

Exercise duration and mood state: how much is enough to feel better?

The effects of exercise duration on mood state were examined. In a repeated-measures design, the Profile of Mood States inventory (D. M. McNair, M. Lorr, & L. F. Droppleman, 1971) was administered before and after 1 quiet resting trial and 3 exercise trials of 10, 20, and 30 min on a bicycle ergometer. Heart rate levels were controlled at 60% of the participant's estimated VO2max level. An overall analysis of variance found improved levels of vigor with reduced levels of confusion, fatigue, and total negative mood. Planned analyses revealed that the improvements in vigor, fatigue, and total mood occurred after 10 min of exercise, with progressive improvements in confusion over 20 min and with no additional improvement over longer periods. These results complement current recommendations, which suggest that to experience positive fitness and health benefits, healthy adults should participate in a total of 30 min of moderate physical exercise daily, accumulated in short bouts throughout the day.

Abdominal vena caval injuries: outcomes remain dismal.

BACKGROUND: The mortality rate for abdominal vena caval injuries remains high. We examined the experience of a level I trauma center to determine factors significant to the outcome in these injuries. METHODS: Forty-seven patients were identified in a retrospective review (1989 to 1999) of patients were identified with abdominal vena caval injury. Data were analyzed by uni- and multivariate methods, including logistic regression. RESULTS: Most of the individuals with abdominal vena caval injuries were young male patients who were injured by penetrating trauma and who were hypotensive on arrival. The severity of injury and the number of organs injured was high. The overall mortality rate was 55%. Nonsurvivors were more often hypotensive in the field with physiologic derangement consistent with hemorrhagic shock. Type and location of injury as well as method of repair were associated with death. Multiple regression analysis revealed that prehospital initial systolic blood pressure and intraoperative bicarbonate levels were independent predictors of survival. CONCLUSIONS: We identified factors related to poor outcome, including suprarenal and retrohepatic location of injury and variables that reflected the evolution of shock. Management should include appropriate resuscitation and ultimately may require novel operative techniques.

Patient preferences regarding possible outcomes of lung resection: what outcomes should preoperative evaluations target?

CONTEXT: Lung resection can lead to significant postoperative complications: Although many reports describe the likelihood of postoperative problems, such as atelectasis, pneumonia, and prolonged ventilator dependence, it is unclear whether patients perceive these outcomes as sufficiently severe to influence their decisions about surgery. OBJECTIVE: To assess patients' preferences regarding possible outcomes of lung resection, including traditional complications reported in the lung surgery literature and outcomes that describe functional limitation. DESIGN: Utility analysis. SETTING: A community hospital internal medicine clinic, a private internal medicine practice, and a private pulmonary practice. PARTICIPANTS: Sixty-four patients, aged 50 to 75 years, who were awaiting appointments at the designated clinic sites. MAIN OUTCOME MEASURE: Patients' strength of preference regarding potential outcomes of lung resection as derived from health utility scores. RESULTS: Common postoperative complications were assigned high utility scores by patients. On a scale for which 1.0 represents perfect health and 0 represents death, postoperative atelectasis, pneumonia, and 3 days of mechanical ventilation were all rated >0.75. Scores describing limited physical function were strikingly low. Specifically, activity limited to bed to chair movement and the need for complete assistance with activities of daily living were all assigned utility scores <0.2. Twenty-four-hour oxygen dependence was scored at 0.33. Presence or absence of pulmonary illness did not predict scores for any outcome. CONCLUSIONS: Whether patients suffer from chronic lung disease or not, they do not regard the postoperative outcomes reported in the lung surgery literature as sufficiently morbid to forego important surgery. However, physical debility is perceived as extremely undesirable, and anticipation of its occurrence could deter surgery. Therefore, identification of preoperative predictors of postoperative physical debility would be invaluable for counseling patients who face difficult decisions about lung resection.

Racial differences in patients' perceptions of debilitated health states.

OBJECTIVE: To determine health utility scores for specific debilitated health states and to identify whether race or other demographic differences predict significant variation in these utility scores. DESIGN: Utility analysis. SETTING: A community hospital general internal medicine clinic, a private internal medicine practice, and a private pulmonary medicine practice. PARTICIPANTS: Sixty-four consecutive patients aged 50 to 75 years awaiting appointments. In order to participate, patients at the pulmonary clinic had to meet prespecified criteria of breathing impairment. MEASUREMENTS: Individuals' strength of preference concerning specific states of limited physical function as measured by the standard gamble technique. MAIN RESULTS: Mean utility scores used to quantitate limitations in physical function were extremely low. Using a scale for which 0 represented death and 1.0 represented normal health, limitation in activities of daily living was rated 0. 19 (95% confidence interval [CI] 0.13, 0.25), tolerance of only bed-to-chair ambulation 0.17 (95% CI 0.11, 0.23), and permanent nursing home placement 0.16 (95% CI 0.10, 0.22). Bivariate analysis identified female gender and African-American race as predictors of higher utility scores ( p

Comparing the delivery of albuterol metered-dose inhaler via an adapter and spacer device in an in vitro infant ventilator lung model.

OBJECTIVE: To compare the delivery of an albuterol metered-dose inhaler (MDI) (Ventolin) via an Aerochamber (Monaghan) with an inline adapter (Medicomp Straight Swivel) in an in vitro infant lung model. METHODS: An in vitro infant lung model was modified to compare the delivery of albuterol MDI 10 inhalations via an Aerochamber with an inline adapter. The adapter and Aerochamber were placed at the endotracheal tube. A 1000 mL intravenous bag filled with 500 mL deionized water was attached to a 3.5 mm endotracheal tube (10 cm length). An Infant Bear Cub ventilator was used at the following settings: positive inspiratory pressure 20 cm H2O, intermittent mandatory ventilation 40 breaths/min, positive end expiratory pressure 4 cm H2O, and inspiratory time 0.5 second. Each device was run at least 10 times and assayed in duplicate by HPLC. An unpaired Student's t-test was used to analyze the statistical significance of the data. RESULTS: There was significantly greater delivery of albuterol with the Aerochamber (19.49 +/- 7.23 microg; 2.17% +/- 0.8%) as compared with an inline adapter (1.0625 +/- 1.36 microg; 0.12% +/- 0.15%) (p = 0.001). CONCLUSIONS: The Aerochamber provides a greater delivery of albuterol metered-dose inhalations to the lung than the inline adapter in an in vitro infant lung model.

Evaluating the delivery of nebulized and metered-dose inhalers in an in vitro infant ventilator lung model.

OBJECTIVE: To evaluate drug delivery to the lungs of nebulized and metered-dose inhalers (MDIs) in an in vitro infant lung model. METHODS: An in vitro lung model was modified to study drug delivery. A 1000 mL intravenous bag filled with 500 mL deionized water was attached to a 3.5 mm (12 cm length) endotracheal tube. An inline Marquest Whisper Jet infant circuit nebulizer system delivered 2.5 mg/3 mL albuterol sulfate inhalation solution (Ventolin nebules) at a flow rate of 5 L/min. An Aerochamber (Monaghan) was placed at the endotracheal tube for the delivery of the MDIs. Albuterol MDI (Ventolin) 10 inhalations and beclomethasone MDI (Beclovent) 20 inhalations were delivered. A Servo 900C (Siemens-Elma) was used at the following ventilator settings: positive inspiratory pressure 30 cm H2O), intermittent mandatory ventilation 40 breaths/min, positive end expiratory pressure 4 cm H2O, inspiratory time 0.4 sec. Each formulation was run at least 10 times and assayed in duplicate by HPLC. An unpaired Student's t-test was used to analyze the statistical significance of the data. RESULTS: There was a significantly greater percentage of drug delivery with MDI albuterol (1.96 +/- 0.50) as compared with nebulized albuterol (1.26 +/- 0.37) (p = 0.002) or beclomethasone diproprionate (0.51 +/- 0.24) (p = 0.001). CONCLUSIONS: Albuterol MDI provides a more efficient delivery of drug to the lung as compared with nebulized albuterol and MDI beclomethasone diproprionate.

Importance of time to reperfusion for 30-day and late survival and recovery of left ventricular function after primary angioplasty for acute myocardial infarction.

OBJECTIVES: The purpose of this study was to evaluate the importance of time to reperfusion for outcomes after primary angioplasty for acute myocardial infarction. BACKGROUND: Survival benefit of thrombolytic therapy for acute myocardial infarction is strongly dependent on time to treatment. Recent observations suggest that time to treatment may be less important for survival with primary angioplasty. METHODS: Consecutive patients (n=1,352) with acute myocardial infarction treated with primary angioplasty were followed for up to 13 years. Paired acute and follow-up ejection fraction data were obtained at cardiac catheterization in 606 patients. RESULTS: Reperfusion was achieved within 2 h in 164 patients (12%). Thirty-day mortality was lowest with early reperfusion (4.3% at <2 h vs. 9.2% at > or = 2 h, p=0.04) and was relatively independent of time to reperfusion after 2 h (9.0% at 2 to 4 h, 9.3% at 4 to 6 h, 9.5% at >6 h). Thirty-day-plus late cardiac mortality was also lowest with early reperfusion (9.1% at <2 h vs. 16.3% at > or = 2 h, p=0.02) and relatively independent at time to reperfusion after 2 h (16.4% at 2 to 4 h, 16.9% at 4 to 6 h, 15.6% at >6 h). Improvement in left ventricular ejection fraction was greatest in the early reperfusion group and relatively modest after 2 h (6.9% at <2 h vs. 3.1% at > or =2 h, p=0.007). CONCLUSIONS: Time to reperfusion, up to 2 h, is important for survival and recovery of left ventricular function. After 2 h, recovery of left ventricular function is modest and survival is relatively independent of time to reperfusion. These data suggest that factors other than myocardial salvage may be responsible for survival benefit in patients treated with primary angioplasty after 2 h.