Polar UVI images to study steady magnetospheric convection events: Initial results

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94804/1/grl20687.pd

Simulating the one‐dimensional structure of Titan's upper atmosphere: 1. Formulation of the Titan Global Ionosphere‐Thermosphere Model and benchmark simulations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94638/1/jgre2819.pd

Simulating the one‐dimensional structure of Titan's upper atmosphere: 3. Mechanisms determining methane escape

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94596/1/jgre2822.pd

Global 30–240 keV proton precipitation in the 17–18 April 2002 geomagnetic storms: 1. Patterns

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95215/1/jgra18503.pd

Simulating the one‐dimensional structure of Titan's upper atmosphere: 2. Alternative scenarios for methane escape

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94984/1/jgre2821.pd

Perioperative strategy in colonic surgery; LAparoscopy and/or FAst track multimodal management versus standard care (LAFA trial)

BACKGROUND: Recent developments in large bowel surgery are the introduction of laparoscopic surgery and the implementation of multimodal fast track recovery programs. Both focus on a faster recovery and shorter hospital stay. The randomized controlled multicenter LAFA-trial (LAparoscopy and/or FAst track multimodal management versus standard care) was conceived to determine whether laparoscopic surgery, fast track perioperative care or a combination of both is to be preferred over open surgery with standard care in patients having segmental colectomy for malignant disease. METHODS/DESIGN: The LAFA-trial is a double blinded, multicenter trial with a 2 × 2 balanced factorial design. Patients eligible for segmental colectomy for malignant colorectal disease i.e. right and left colectomy and anterior resection will be randomized to either open or laparoscopic colectomy, and to either standard care or the fast track program. This factorial design produces four treatment groups; open colectomy with standard care (a), open colectomy with fast track program (b), laparoscopic colectomy with standard care (c), and laparoscopic surgery with fast track program (d). Primary outcome parameter is postoperative hospital length of stay including readmission within 30 days. Secondary outcome parameters are quality of life two and four weeks after surgery, overall hospital costs, morbidity, patient satisfaction and readmission rate. Based on a mean postoperative hospital stay of 9 +/- 2.5 days a group size of 400 patients (100 each arm) can reliably detect a minimum difference of 1 day between the four arms (alfa = 0.95, beta = 0.8). With 100 patients in each arm a difference of 10% in subscales of the Short Form 36 (SF-36) questionnaire and social functioning can be detected. DISCUSSION: The LAFA-trial is a randomized controlled multicenter trial that will provide evidence on the merits of fast track perioperative care and laparoscopic colorectal surgery in patients having segmental colectomy for malignant disease

FTA: A Feature Tracking Empirical Model of Auroral Precipitation

The Feature Tracking of Aurora (FTA) model was constructed using 1.5 years of Polar Ultraviolet Imager data and is based on tracking a cumulative energy grid in 96 magnetic local time (MLT) sectors. The equatorward boundary, poleward boundary, and 19 cumulative energy bins are tracked with the energy flux and the latitudinal position. With AE increasing, the equatorward boundary moves to lower latitudes everywhere, while the poleward boundary moves poleward in the 2300–0300 MLT region and equatorward in other MLT sectors. This results in the aurora getting wider on the nightside and becoming narrower on the dayside. The peak intensity of the aurora in each MLT sector is almost linearly related to AE, with the global peak moving from pre‐midnight to post‐midnight as geomagnetic activity increases. Ratios between the Lyman‐Birge‐Hopfield‐long and ‐short models allow the average energy to be calculated. Predictions from the FTA and two other auroral models were compared to the measurements by the Defense Meteorological Satellite Program Special Sensor Ultraviolet Spectrographic Imagers (SSUSI) on March 17, 2013. Among the three models, the FTA model specified the most confined patterns with the highest energy flux, agreeing with the spatial and temporal evolution of SSUSI measurements better and predicted auroral power (AP) better during higher activity levels (SSUSI AP > 20 GW). The Fuller‐Rowell and Evans (1987) and FTA models specified very similar average energy compared with SSUSI measurements, doing slightly better by ∼1 keV than the OVATION Prime model.Key PointsThe AE‐based Feature Tracking of Aurora (FTA) model provides the energy flux and the average energy using 1.5 years of Polar Ultraviolet Imager dataThe FTA model’s grid is tied to auroral boundaries and spatial distribution: tracking a cumulative energy grid in each magnetic local time sectorFor the March 17, 2013 event, the FTA model had the most confined patterns and agreed best with Special Sensor Ultraviolet Spectrographic Imagers observations of auroral powerPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167826/1/swe21144.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167826/2/swe21144_am.pd

Dependence of the global dayside reconnection rate on interplanetary magnetic field By and the earth’s dipole tilt

Abstract In the recent years, significant attention has been given to the combined effect of Interplanetary Magnetic Field (IMF) duskward component (By) and dipole tilt on the global magnetosphere-ionosphere system response. Numerous studies have pointed out that when the Earth’s magnetic dipole is tilted away from the Sun (negative dipole tilt during northern winter), and IMF has a positive By component, the effects on ionospheric currents, particle precipitation, ionospheric convection, and average size of the auroral oval, is significantly more enhanced, compared to when IMF By is negative. Furthermore, this IMF By polarity effect reverses when Earth’s dipole is tilted in the opposite direction. The underlying cause has remained unclear. Our analysis shows that substorms tend to be stronger during the same IMF By and dipole tilt polarity combination. Taken together with earlier results showing also more frequent substorms during the same conditions, our observations suggests that when IMF By and dipole tilt have opposite signs, there is a more efficient global dayside reconnection rate. We also show analysis of the occurrence frequency of periods of Steady Magnetospheric Convection, substorm onset latitude, and the isotropic boundary of proton precipitation, that are all consistent with our conclusion that the combination of IMF By and dipole tilt polarity affect the global dayside reconnection rate