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"Pizzo, J."
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Physics basis for the Wisconsin HTS Axisymmetric Mirror (WHAM)
by
Petrov, Yu.V.
,
Egedal, J.
,
Qian, T.
in
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
,
Beam injection
,
Charge exchange
2023
The Wisconsin high-temperature superconductor axisymmetric mirror experiment (WHAM) will be a high-field platform for prototyping technologies, validating interchange stabilization techniques and benchmarking numerical code performance, enabling the next step up to reactor parameters. A detailed overview of the experimental apparatus and its various subsystems is presented. WHAM will use electron cyclotron heating to ionize and build a dense target plasma for neutral beam injection of fast ions, stabilized by edge-biased sheared flow. At 25 keV injection energies, charge exchange dominates over impact ionization and limits the effectiveness of neutral beam injection fuelling. This paper outlines an iterative technique for self-consistently predicting the neutral beam driven anisotropic ion distribution and its role in the finite beta equilibrium. Beginning with recent work by Egedal et al. (Nucl. Fusion, vol. 62, no. 12, 2022, p. 126053) on the WHAM geometry, we detail how the FIDASIM code is used to model the charge exchange sources and sinks in the distribution function, and both are combined with an anisotropic magnetohydrodynamic equilibrium solver method to self-consistently reach an equilibrium. We compare this with recent results using the CQL3D code adapted for the mirror geometry, which includes the high-harmonic fast wave heating of fast ions.
Journal Article
Numerical Heliospheric Simulations as Assisting Tool for Interpretation of Observations by STEREO Heliospheric Imagers
by
Odstrcil, Dusan
,
Pizzo, Victor J.
in
Astrophysics
,
Astrophysics and Astroparticles
,
Atmospheric Sciences
2009
The interpretation of multi-spacecraft heliospheric observations and three-dimensional reconstruction of structured and evolving solar wind is challenging. This is especially true for the interpretation of white-light structures observed by the Heliospheric Imagers (HI) onboard STEREO spacecraft since their appearance depends on three-dimensional geometric factors. Numerical simulations can provide global context and suggest what may and may not be observed. We use the heliospheric code ENLIL to simulate various scenarios of well-defined corotating solar wind streams and ejected transient density structures, and we generate from the solutions synthetic white-light images at various locations. We illustrate that corotating interaction regions (CIRs) show up differently in HI-2A and HI-2B and that they may appear as transient structures in HI-2A but not in HI-2B. This asymmetry is caused by differing Thomson scattering responses. Further, we illustrate that a given interplanetary coronal mass ejection (ICME) may exhibit drastically different white-light brightness depending on the observing position and that some ICMEs can eventually reach Earth without being detected by the imagers. Finally, we demonstrate application of the modeling system through simulation of the 24 – 25 January 2007, 31 December 2007 and 26 April 2008 CMEs.
Journal Article
Prospects for a high-field, compact break-even axisymmetric mirror (BEAM) and applications
2024
This paper explores the feasibility of a break-even-class mirror referred to as BEAM (break-even axisymmetric mirror): a neutral-beam-heated simple mirror capable of thermonuclear-grade parameters and $Q\\sim 1$ conditions. Compared with earlier mirror experiments in the 1980s, BEAM would have: higher-energy neutral beams, a larger and denser plasma at higher magnetic field, both an edge and a core and capabilities to address both magnetohydrodynamic and kinetic stability of the simple mirror in higher-temperature plasmas. Axisymmetry and high-field magnets make this possible at a modest scale enabling a short development time and lower capital cost. Such a $Q\\sim 1$ configuration will be useful as a fusion technology development platform, in which tritium handling, materials and blankets can be tested in a real fusion environment, and as a base for development of higher-$Q$ mirrors.
Journal Article
Formation and Evolution of Corotating Interaction Regions and their Three Dimensional Structure
1999
Corotating interaction regions are a consequence of spatial variability in the coronal expansion and solar rotation, which cause solar wind flows of different speeds to become radially aligned. Compressive interaction regions are produced where high-speed wind runs into slower plasma ahead. When the flow pattern emanating from the Sun is roughly time-stationary these compression regions form spirals in the solar equatorial plane that corotate with the Sun, hence the name corotating interaction regions, or CIRs. The leading edge of a CIR is a forward pressure wave that propagates into the slower plasma ahead, while the trailing edge is a reverse pressure wave that propagates back into the trailing high-speed flow. At large heliocentric distances the pressure waves bounding a CIR commonly steepen into forward and reverse shocks. Spatial variation in the solar wind outflow from the Sun is a consequence of the solar magnetic field, which modulates the coronal expansion. Because the magnetic equator of the Sun is commonly both warped and tilted with respect to the heliographic equator, CIRs commonly have substantial north-south tilts that are opposed in the northern and southern hemispheres. Thus, with increasing heliocentric distance the forward waves in both hemispheres propagate toward and eventually across the solar equatorial plane, while the reverse shocks propagate poleward to higher latitudes. This paper provides an overview of observations and numerical models that describe the physical origin and radial evolution of these complex three-dimensional (3-D) heliospheric structures.[PUBLICATION ABSTRACT]
Journal Article
Cross-generational impact of a male murine pheromone 2-sec-butyl-4,5-dihydrothiazole in female mice
by
Pizzo, Matthew J.
,
Novotny, Milos V.
,
Wager-Miller, James
in
Animals
,
Cognition - drug effects
,
Cognitive Function
2015
The current understanding of the activity of mammalian pheromones is that endocrine and behavioural effects are limited to the exposed individuals. Here, we demonstrate that the nasal exposure of female mice to a male murine pheromone stimulates expansion of mammary glands, leading to prolonged nursing of pups. Subsequent behavioural testing of the pups from pheromone-exposed dams exhibited enhanced learning. Sialic acid components in the milk are known to be involved in brain development. We hypothesized that the offspring might have received more of this key nutrient that promotes brain development. The mRNA for polysialyltransferase, which produces polysialylated neural cell adhesion molecules related to brain development, was increased in the brain of offspring of pheromone-exposed dams at post-natal day 10, while it was not different at embryonic stages, indicating possible differential brain development during early post-natal life.
Journal Article
A unified model of solar energetic particle transport in structured solar wind
2009
Solar energetic particle (SEP) fluxes, after their propagation from the particles' source to the Earth's orbit, depend on the state of solar wind, which is known to be highly variable in both time and space. Commonly used SEP transport models are based on the assumption of the standard interplanetary magnetic field, which would be the case for a uniform, steady state expansion of solar wind. Modeling of SEP transport in the standard solar wind can be facilitated by the use of a corotating reference frame, wherein the solar wind speed is parallel to interplanetary magnetic field at each point and the magnetic field is static. However, this approach is not possible in the realistic solar wind. This necessitates development of a more general SEP model applicable to particle transport in arbitrarily structured solar wind and in interplanetary coronal mass ejections, magnetic clouds, and shocks. In the framework of focused transport theory, we formulate a practical model of SEP transport in an evolving, structured solar wind. This unified model accommodates the results of three‐dimensional MHD modeling of solar wind based on observations of the sun, solar wind, and SEPs in a particular event. A relation between the generalized focused transport model and the diffusion‐convection equation of cosmic ray transport is discussed.
Journal Article
Preoperative radiographic parameters predict long-term renal impairment following partial nephrectomy
by
Del Pizzo, Joseph J.
,
Shih, George
,
Mazumdar, Madhu
in
Aged
,
Carcinoma, Renal Cell - diagnostic imaging
,
Carcinoma, Renal Cell - pathology
2013
Purpose
We analyzed radiographic parameters describing anatomic features of renal tumors to identify preoperative characteristics that could help predict long-term decline in renal function following partial nephrectomy.
Methods
We retrospectively reviewed the records of 194 consecutive patients who underwent partial nephrectomy from January 2006 to March 2009 and analyzed a cohort of 53 patients for whom complete clinical, radiographic, and operative information was available. Computed tomography images were reviewed by a single radiologist. Radiographic criteria for describing renal tumor size and location included diameter, volume, endophytic properties, proximity to collecting system, anterior/posterior location, location relative to polar lines, and R.E.N.A.L. nephrometry score. Postoperative estimated glomerular filtration rate was calculated using the MDRD study group equation with serum creatinine at last follow-up.
Results
The median preoperative and postoperative GFR values were 75 (IQR 65–97) and 66 (IQR 55–84) mL/min/1.73 m
2
, respectively. At a median follow-up of 38 months, the median percentage decrease in GFR was 12%. On univariate analyses, tumor diameter (
P
= 0.002), tumor volume (
P
< 0.0001), nearness of tumor to collecting system (
P
= 0.017), and location relative to polar lines (
P
= 0.017) were associated with percentage decrease in GFR. Furthermore, higher R.E.N.A.L. nephrometry score was also associated with poorer renal functional outcomes following partial nephrectomy (
P
= 0.019).
Conclusions
Anatomic features of renal tumors defined by preoperative radiographic characteristics correlate with the degree of renal functional decline after partial nephrectomy. Identification of these parameters may assist in patient counseling and clinical decision making following partial nephrectomy. Validation in larger prospective studies is necessary.
Journal Article
Loss of Cell Cycle Regulators p27Kip1 and Cyclin E in Transitional Cell Carcinoma of the Bladder Correlates with Tumor Grade and Patient Survival
by
Kyprianou, Natasha
,
Jacobs, Stephen C
,
Del Pizzo, Joseph J
in
Biological and medical sciences
,
Medical sciences
,
Nephrology. Urinary tract diseases
1999
The cyclin-dependent kinase inhibitor p27(Kip1) is a powerful molecular determinant of cell cycle progression. Loss of expression of p27(Kip1) has been shown to be predictive of disease progression in several human malignancies. In this study we investigated the expression of two key cell cycle regulators, p27(Kip1) and cyclin E, in the progression of transitional cell carcinoma of the bladder. An immunohistochemical analysis was conducted in a series of 50 bladder tumor specimens, including 3 metastatic lymph nodes, and 7 normal bladder specimens, using specific antibodies against the two regulators of the cell cycle, p27(Kip1) and cyclin E. The degree of immunoreactivity was correlated with the pathological tumor grade, stage, and patient survival. A uniformly intense immunoreactivity for p27(Kip1) and cyclin E was observed in epithelial cells of normal bladder tissue. Malignant bladder tissue demonstrated a heterogeneous pattern of significantly reduced p27(Kip1) and cyclin E immunoreactivity, compared with normal urothelium (P < 0.01). In addition, there was progressive loss of expression of both cell cycle proteins with increasing tumor grade and pathological stage. Expression of p27(Kip1) was significantly lower in the poorly differentiated tumors (grades III) compared to well and moderately differentiated (grades I and II) tumors (P = 0.004). Moreover, the expression of cyclin E was lower in grade III tumors compared to grade I and II lesions, although this difference failed to reach statistical significance. Most significantly, Kaplan-Meier plots of patient survival show increased mortality risk associated with low levels of p27(Kip1) (P = 0.001) and cyclin E (P = 0.002) expression. This is the first evidence that loss of expression of p27(Kip1) and cyclin E in human bladder transitional cell carcinoma cells correlates with advancing histological aggressiveness and poor patient survival. These results have clinical importance, because they support a role for p27(Kip1) and cyclin E as novel predictive markers of the biological potential of bladder tumors that will enable identification of those tumors most likely to progress to muscle invasive disease and of patient survival.
Journal Article
THE EFFECT OF CHANGES IN CRITERION VALUE ON DIFFERENTIAL REINFORCEMENT OF LOW RATE SCHEDULE PERFORMANCE
by
Pizzo, Matthew J.
,
Blundell, Pamela J.
,
Kirkpatrick, Kimberly
in
Animal Behavior
,
Animals
,
Body Composition
2009
The differential reinforcement of low rate (DRL) schedule is commonly used to assess impulsivity, hyperactivity, and the cognitive effects of pharmacological treatments on performance. A DRL schedule requires subjects to wait a certain minimum amount of time between successive responses to receive reinforcement. The DRL criterion value, which specifies the minimum wait time between responses, is often shifted towards increasingly longer values over the course of training. However, the process invoked by shifting DRL values is poorly understood. Experiment 1 compared performance on a DRL 30‐s schedule versus a DRL 15‐s schedule that was later shifted to a DRL 30‐s schedule. Dependent measures assessing interresponse time (IRT) production and reward‐earning efficiency showed significant detrimental effects following a DRL schedule transition in comparison with the performance on a maintained DRL 30‐s schedule. Experiments 2a and 2b assessed the effects of small incremental changes vs. a sudden large shift in the DRL criterion on performance. The incremental changes produced little to no disruption in performance compared to a sudden large shift. The results indicate that the common practice of incrementing the DRL criterion over sessions may be an inefficient means of training stable DRL performance.
Journal Article
The NOAA Goes-12 Solar X-Ray Imager (SXI) 1. Instrument, Operations, and Data
2005
The Solar X-ray Imager (SXI) was launched 23 July 2001 on NOAA's GOES-12 satellite and completed post-launch testing 20 December 2001. Beginning 22 January 2003 it has provided nearly uninterrupted, full-disk, soft X-ray solar images, with a continuous frame rate significantly exceeding that for previous similar instruments. The SXI provides images with a 1 min cadence and a single-image (adjustable) dynamic range near 100. A set of metallic thin-film filters provides temperature discrimination in the 0.6 - 6.0 nm bandpass. The spatial resolution of approximately 10 arcsec FWHM is sampled with 5 arcsec pixels. Three instrument degradations have occurred since launch, two affecting entrance filters and one affecting the detector high-voltage system. This work presents the SXI instrument, its operations, and its data processing, including the impacts of the instrument degradations. A companion paper (Pizzo et al., this issue) presents SXI performance prior to an instrument degradation that occurred on 5 November 2003 and thus applies to more than 420000 soft X-ray images of the Sun.
Journal Article