575 research outputs found
Extrasolar Planet Interactions
The dynamical interactions of planetary systems may be a clue to their
formation histories. Therefore, the distribution of these interactions provides
important constraints on models of planet formation. We focus on each system's
apsidal motion and proximity to dynamical instability. Although only ~25
multiple planet systems have been discovered to date, our analyses in these
terms have revealed several important features of planetary interactions. 1)
Many systems interact such that they are near the boundary between stability
and instability. 2) Planets tend to form such that at least one planet's
eccentricity periodically drops to near zero. 3) Mean-motion resonant pairs
would be unstable if not for the resonance. 4) Scattering of approximately
equal mass planets is unlikely to produce the observed distribution of apsidal
behavior. 5) Resonant interactions may be identified through calculating a
system's proximity to instability, regardless of knowledge of angles such as
mean longitude and longitude of periastron (e.g. GJ 317 b and c are probably in
a 4:1 resonance). These properties of planetary systems have been identified
through calculation of two parameters that describe the interaction. The
apsidal interaction can be quantified by determining how close a planet is to
an apsidal separatrix (a boundary between qualitatively different types of
apsidal oscillations, e.g. libration or circulation of the major axes). The
proximity to instability can be measured by comparing the observed orbital
elements to an analytic boundary that describes a type of stability known as
Hill stability. We have set up a website dedicated to presenting the most
up-to-date information on dynamical interactions:
http://www.lpl.arizona.edu/~rory/research/xsp/dynamicsComment: 10 pages, 3 figures, 1 table. To appear in the proceedings of IAU
Symposium 249: Exoplanets: Detection, Formation and Dynamics, held in Suzhou,
China, Oct 22-26 2007. A version with full resolution figures is available at
http://www.lpl.arizona.edu/~rory/publications/bg08a.pd
The role of technology in healthy living medicine
Health care consumers are taking control of their health information and desire a greater role in managing their health. Approximately 77% of Americans now own a smartphone and the use of health apps have doubled over the past two years. These effects are particularly notable in patients with chronic disease, now representing half the adult population and responsible for 86% of United States health care (HC) costs and 70% of deaths. New opportunities exist as a result of recent advances in home-based wireless devices, apps, wearables, and interactive systems enabling health delivery systems to monitor, advise and treat disease near real time and engage patients in healthy living medicine. These technologies will provide a new framework for patient engagement and care delivery that will enhance clinical outcomes and generate precision interventions that ultimately reduce HC costs
Efficient intra- and inter-night linking of asteroid detections using kd-trees
The Panoramic Survey Telescope And Rapid Response System (Pan-STARRS) under
development at the University of Hawaii's Institute for Astronomy is creating
the first fully automated end-to-end Moving Object Processing System (MOPS) in
the world. It will be capable of identifying detections of moving objects in
our solar system and linking those detections within and between nights,
attributing those detections to known objects, calculating initial and
differentially-corrected orbits for linked detections, precovering detections
when they exist, and orbit identification. Here we describe new kd-tree and
variable-tree algorithms that allow fast, efficient, scalable linking of intra
and inter-night detections. Using a pseudo-realistic simulation of the
Pan-STARRS survey strategy incorporating weather, astrometric accuracy and
false detections we have achieved nearly 100% efficiency and accuracy for
intra-night linking and nearly 100% efficiency for inter-night linking within a
lunation. At realistic sky-plane densities for both real and false detections
the intra-night linking of detections into `tracks' currently has an accuracy
of 0.3%. Successful tests of the MOPS on real source detections from the
Spacewatch asteroid survey indicate that the MOPS is capable of identifying
asteroids in real data.Comment: Accepted to Icaru
Health Care 2020: Reengineering Health Care Delivery to Combat Chronic Disease
Chronic disease has become the great epidemic of our times, responsible for 75% of total health care costs and the majority of deaths in the US. Our current delivery model is poorly constructed to manage chronic disease, as evidenced by low adherence to quality indicators and poor control of treatable conditions. New technologies have emerged that can engage patients and offer additional modalities in the treatment of chronic disease. Modifying our delivery model to include team-based care in concert with patient-centered technologies offers great promise in managing the chronic disease epidemic
A Novel t(8;14)(q24;q11) Rearranged Human Cell Line as a Model for Mechanistic and Drug Discovery Studies of NOTCH1-Independent Human T-Cell Leukemia
MYC-translocated T-lineage acute lymphoblastic leukemia (T-ALL) is a rare subgroup of T-ALL associated with CDKN2A/B deletions, PTEN inactivation, and absence of NOTCH1 or FBXW7 mutations. This subtype of T-ALL has been associated with induction failure and aggressive disease. Identification of drug targets and mechanistic insights for this disease are still limited. Here, we established a human NOTCH1-independent MYC-translocated T-ALL cell line that maintains the genetic and phenotypic characteristics of the parental leukemic clone at diagnosis. The University of Padua T-cell acute lymphoblastic leukemia 13 (UP-ALL13) cell line has all the main features of the above described MYC-translocated T-ALL. Interestingly, UP-ALL13 was found to harbor a heterozygous R882H DNMT3A mutation typically found in myeloid leukemia. Chromatin immunoprecipitation coupled with high-throughput sequencing for histone H3 lysine 27 (H3K27) acetylation revealed numerous putative super-enhancers near key transcription factors, including MYC, MYB, and LEF1. Marked cytotoxicity was found following bromodomain-containing protein 4 (BRD4) inhibition with AZD5153, suggesting a strict dependency of this particular subtype of T-ALL on the activity of super-enhancers. Altogether, this cell line may be a useful model system for dissecting the signaling pathways implicated in NOTCH1-independent T-ALL and for the screening of targeted anti-leukemia agents specific for this T-ALL subgroup
Obesity and cardiovascular diseases: implications regarding fitness, fatness, and severity in the obesity paradox
Obesity has been increasing in epidemic proportions, with a disproportionately higher increase in morbid or class III obesity, and obesity adversely affects cardiovascular (CV) hemodynamics, structure, and function, as well as increases the prevalence of most CV diseases. Progressive declines in physical activity over 5 decades have occurred and have primarily caused the obesity epidemic. Despite the potential adverse impact of overweight and obesity, recent epidemiological data have demonstrated an association of mild obesity and, particularly, overweight on improved survival. We review in detail the obesity paradox in CV diseases where overweight and at least mildly obese patients with most CV diseases seem to have a better prognosis than do their leaner counterparts. The implications of cardiorespiratory fitness with prognosis are discussed, along with the joint impact of fitness and adiposity on the obesity paradox. Finally, in light of the obesity paradox, the potential value of purposeful weight loss and increased physical activity to affect levels of fitness is reviewed
Impact of echocardiographic left ventricular geometry on clinical prognosis
Abnormal left ventricular (LV) geometry, including LV hypertrophy (LVH), is associated with increased risk of major cardiovascular (CV) events and all-cause mortality and may be an independent predictor of morbid CV events. Patients with LVH have increased risk of congestive heart failure, coronary heart disease, sudden cardiac death and stroke. We review the risk factors for LVH and its consequences, as well as the risk imposed by concentric remodeling (CR). We also examine evidence supporting the benefits of LVH regression, as well as evidence regarding the risk of CR progressing to LVH, as opposed to normalization of CR. We also briefly review the association of abnormal LV geometry with left atrial enlargement and the combined effects of these structural cardiac abnormalities
Improving hypertension control and patient engagement using digital tools
Hypertension is present in 30% of the adult US population and is a major contributor to cardiovascular disease. The established office-based approach yields only 50% blood pressure control rates and low levels of patient engagement. Available home technology now provides accurate, reliable data that can be transmitted directly to the electronic medical record. We evaluated blood pressure control in 156 patients with uncontrolled hypertension enrolled into a home-based digital-medicine blood pressure program and compared them with 400 patients (matched to age, sex, body mass index, and blood pressure) in a usual-care group after 90 days. Digital-medicine patients completed questionnaires online, were asked to submit at least one blood pressure reading/week, and received medication management and lifestyle recommendations via a clinical pharmacist and a health coach. Blood pressure units were commercially available that transmitted data directly to the electronic medical record. Digital-medicine patients averaged 4.2 blood pressure readings per week. At 90 days, 71% of digital-medicine vs 31% of usual-care patients had achieved target blood pressure control. Mean decrease in systolic/diastolic blood pressure was 14/5 mm Hg in digital medicine, vs 4/2 mm Hg in usual care (
- …