Jones E.S.,McKinsey and Co. |
Soatto S.,University of California at Los Angeles
International Journal of Robotics Research | Year: 2011
We describe a model to estimate motion from monocular visual and inertial measurements. We analyze the model and characterize the conditions under which its state is observable, and its parameters are identifiable. These include the unknown gravity vector, and the unknown transformation between the camera coordinate frame and the inertial unit. We show that it is possible to estimate both state and parameters as part of an on-line procedure, but only provided that the motion sequence is 'rich enough', a condition that we characterize explicitly. We then describe an efficient implementation of a filter to estimate the state and parameters of this model, including gravity and camera-to-inertial calibration. It runs in real-time on an embedded platform. We report experiments of continuous operation, without failures, re-initialization, or re-calibration, on paths of length up to 30 km. We also describe an integrated approach to 'loop-closure', that is the recognition of previously seen locations and the topological re-adjustment of the traveled path. It represents visual features relative to the global orientation reference provided by the gravity vector estimated by the filter, and relative to the scale provided by their known position within the map; these features are organized into 'locations' defined by visibility constraints, represented in a topological graph, where loop-closure can be performed without the need to re-compute past trajectories or perform bundle adjustment. The software infrastructure as well as the embedded platform is described in detail in a previous technical report. © 2011 The Author(s).
Tsao J.,Novartis |
Tsao J.,McKinsey and Co. |
Kozerke S.,ETH Zurich
Journal of Magnetic Resonance Imaging | Year: 2012
In recent years, there has been an explosive growth of magnetic resonance imaging (MRI) techniques that allow faster scan speed by exploiting temporal or spatiotemporal redundancy of the images. These techniques improve the performance of dynamic imaging significantly across multiple clinical applications, including cardiac functional examinations, perfusion imaging, blood flow assessment, contrast-enhanced angiography, functional MRI, and interventional imaging, among others. The scan acceleration permits higher spatial resolution, increased temporal resolution, shorter scan duration, or a combination of these benefits. Along with the exciting developments is a dizzying proliferation of acronyms and variations of the techniques. The present review attempts to summarize this rapidly growing topic and presents conceptual frameworks to understand these techniques in terms of their underlying mechanics and connections. Techniques from view sharing, keyhole, k-t, to compressed sensing are covered. J. Magn. Reson. Imaging 2012;36:543-560. © 2012 Wiley Periodicals, Inc.
Carrillo R.A.,Yale University |
Carrillo R.A.,California Institute of Technology |
Olsen D.P.,Yale University |
Olsen D.P.,Duke University |
And 3 more authors.
Neuron | Year: 2010
Establishing synaptic connections often involves the activity-dependent withdrawal of off-target contacts. We describe an in vivo role for temporally patterned electrical activity, voltage-gated calcium channels, and CaMKII in modulating the response of Drosophila motoneurons to the chemorepellent Sema-2a during synaptic refinement. Mutations affecting the Sema-2a ligand, the plexin B receptor (plexB), the voltage-gated Ca(v)2.1 calcium channel (cac), or the voltage-gated Na(v)1 sodium channel (mlenap-ts;tipE) each result in ectopic neuromuscular contacts. Sema-2a interacts genetically with both of the channel mutations. The cac phenotype is enhanced by the Sema-2a mutation and is suppressed by either plexB overexpression or patterned, low-frequency (0.01 Hz) bouts of electrical activity in the embryo. The calcium-dependent suppression of ectopic contacts also depends on the downstream activation of CaMKII. These results indicate a role for patterned electrical activity and presynaptic calcium signaling, acting through CaMKII, in modulating a retrograde signal during the refinement of synaptic connections. © 2010 Elsevier Inc.
Chetty R.,Stanford University |
Stepner M.,Massachusetts Institute of Technology |
Abraham S.,Massachusetts Institute of Technology |
Lin S.,McKinsey and Co. |
And 4 more authors.
JAMA - Journal of the American Medical Association | Year: 2016
IMPORTANCE: The relationship between income and life expectancy is well established but remains poorly understood. OBJECTIVES: To measure the level, time trend, and geographic variability in the association between income and life expectancy and to identify factors related to small area variation. DESIGN AND SETTING: Income data for the US population were obtained from 1.4 billion deidentified tax records between 1999 and 2014. Mortality data were obtained from Social Security Administration death records. These data were used to estimate race- and ethnicity-adjusted life expectancy at 40 years of age by household income percentile, sex, and geographic area, and to evaluate factors associated with differences in life expectancy. EXPOSURE: Pretax household earnings as a measure of income. MAIN OUTCOMES AND MEASURES Relationship between income and life expectancy; trends in life expectancy by income group; geographic variation in life expectancy levels and trends by income group; and factors associated with differences in life expectancy across areas. RESULTS: The sample consisted of 1 408 287 218 person-year observations for individuals aged40 to 76years (mean age, 53.0years; median household earnings among working individuals, $61 175 per year). Therewere 4 114 380 deaths amongmen(mortality rate, 596.3 per 100 000) and 2 694 808deathsamongwomen(mortalityrate, 375.1 per100 000). The analysis yielded 4 results. First, higher income was associated with greater longevity throughout the income distribution. The gapin life expectancy between the richest 1% and poorest 1% of individuals was 14.6 years (95%CI, 14.4 to 14.8 years) formen and 10.1 years (95%CI,9.9 to 10.3 years) forwomen. Second, inequality in life expectancy increased over time. Between 2001 and 2014, life expectancy increased by 2.34 years formenand 2.91 years forwomen in the top 5%of the income distribution, but by only0.32 yearsformenand0.04yearsforwomeninthebottom5%(P <.001forthedifferencesforbothsexes). Third, life expectancy for low-income individuals varied substantially across local areas. In the bottomincomequartile, lifeexpectancydifferedbyapproximately4.5yearsbetweenareaswiththe highestandlowest longevity.Changes inlifeexpectancybetween2001and2014 rangedfromgains of more than 4 years to losses of more than 2 years across areas. Fourth, geographic differences in lifeexpectancyfor individuals inthelowestincomequartilewere significantly correlatedwithhealth behaviorssuchassmoking(r = -0.69,P <.001),butwerenotsignificantly correlated with access to medical care, physical environmental factors, income inequality, or labor market conditions. Life expectancy for low-income individualswas positively correlated with the local area fraction of immigrants (r = 0.72, P <.001), fraction of college graduates (r = 0.42, P <.001), and government expenditures (r = 0.57, P <.001). CONCLUSIONS AND RELEVANCE: In the United States between 2001 and 2014, higher income was associated with greater longevity, and differences in life expectancy across income groups increased over time. However, the association between life expectancy and income varied substantially across areas; differences in longevity across income groups decreased in some areas and increased in others. The differences in life expectancy were correlated with health behaviors and local area characteristics. © 2016 American Medical Association. All rights reserved.
Corbett S.,McKinsey and Co.
Healthcare Papers | Year: 2012
The authors of "Chartbook: Shining a Light on the Quality of Healthcare in Canada," focus on building a Canadian healthcare performance baseline, highlighting opportunities to improve the system and then raising policy questions. This is a thoughtful approach to gaining awareness of the relative performance across the Canadian healthcare system. In essence, it is necessary to first establish a felt need, identify areas to improve and then ensure the system will implement the necessary changes to improve. The authors build a reasonable case for why improvements are necessary, and they identify key barriers that must be removed to actually realize improvements and offer a wide range of policy recommendations. However, not all of these recommendations are focused on the key point of ensuring that there are incentives in place to drive participants to implement changes.
Pak J.,Stanford University |
Maniar J.M.,Stanford University |
Maniar J.M.,McKinsey and Co. |
Mello C.C.,Stanford University |
Fire A.,Stanford University
Cell | Year: 2012
The effectiveness of RNA interference (RNAi) in many organisms is potentiated through the signal-amplifying activity of a targeted RNA-directed RNA polymerase (RdRP) system that can convert a small population of exogenously-encountered dsRNA fragments into an abundant internal pool of small interfering RNA (siRNA). As for any biological amplification system, we expect an underlying architecture that will limit the ability of a randomly encountered trigger to produce an uncontrolled and self-escalating response. Investigating such limits in Caenorhabditis elegans, we find that feed-forward amplification is limited by biosynthetic and structural distinctions at the RNA level between (1) triggers that can produce amplification and (2) siRNA products of the amplification reaction. By assuring that initial (primary) siRNAs can act as triggers but not templates for activation, and that the resulting (secondary) siRNAs can enforce gene silencing on additional targets without unbridled trigger amplification, the system achieves substantial but fundamentally limited signal amplification. © 2012 Elsevier Inc.
Cohen S.B.,McKinsey and Co.
The American journal of managed care | Year: 2010
In healthcare, consumerism is not a product or program. Instead, it is an orientation to new care delivery models that encourage and enable greater patient responsibility through the intelligent use of information technology. Despite the promise of consumerism, current approaches have not fully realized the potential benefits of improved outcomes and lower cost. We recommend 4 guiding principles to ensure that next-generation innovation yields the returns that providers, patients, and other stakeholders expect: (1) keep the consumer at the center of innovation, (2) keep it simple, (3) link products and services to a broader "ecosystem" of care, and (4) encourage health in addition to treating illness. Now may be a particularly compelling time to invest in a consumerist approach.
Turner A.W.,University of Melbourne |
Mulholland W.J.,McKinsey and Co. |
Taylor H.R.,University of Melbourne
Clinical and Experimental Ophthalmology | Year: 2011
Background: This paper aims to describe models for service integration between ophthalmology and optometry when conducting outreach eye services. The effect of good coordination on clinical activity and cost-effectiveness is examined. Design: Cross-sectional case study based on remote outreach ophthalmology services in Australia. Participants: Key stake-holders from eye services in nine outreach regions participated in the study. Methods: Semistructured interviews were conducted to perform a qualitative assessment of outreach eye services' levels of coordination. Records of clinical activity were used to statistically compare the effects of good coordination. Main Outcome Measures: Clinical activity (surgery and clinic consultation rates), waiting times and costs per attendance. Surgical case rate being the proportion of surgery that results from a clinic. Results: Service integration between optometry and ophthalmology resulted in an increased surgical case rate for ophthalmology clinics (R 2=0.57). There were trends towards increased clinical activity and reduced waiting times, and costs/attendance were stable. Conclusions: Coordination of eye services with better integration of ophthalmology and optometry roles may improve efficiency of services for patients. Coordination of eye services has multiple facets including facilitating engagement with the local community, eye professions and health facilities. The varied roles of eye health coordination require further definition and appropriate funding. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.
Mani S.R.,Yale University |
Megosh H.,Duke University |
Megosh H.,McKinsey and Co. |
Lin H.,Yale University |
Lin H.,Duke University
Developmental Biology | Year: 2014
PIWI proteins, a subfamily of the ARGONAUTE/PIWI protein family, have been implicated in transcriptional and posttranscriptional gene regulation and transposon silencing mediated by small non-coding RNAs, especially piRNAs. Although these proteins are known to be required for germline development, their somatic function remains elusive. Here, we examine the maternal function of all three PIWI proteins in Drosophila; Piwi, Aubergine (Aub) and Argonaute3 (Ago3) during early embryogenesis. In syncytial embryos, Piwi displays an embryonic stage-dependent localization pattern. Piwi is localized in the cytoplasm during mitotic cycles 1-10. Between cycles 11 and 14, Piwi remains in the cytoplasm during mitosis but moves into the somatic nucleus during interphase. Beyond cycle 14, it stays in the nucleus. Aub and Ago3 are diffusely cytoplasmic from cycle 1 to 14. Embryos maternally depleted of any one of the three PIWI proteins display severe mitotic defects, including abnormal chromosome and nuclear morphology, cell cycle arrest, asynchronous nuclear division and aberrant nuclear migration. Furthermore, all three PIWI proteins are required for the assembly of mitotic machinery and progression through mitosis. Embryos depleted of maternal PIWI proteins also exhibit chromatin organization abnormalities. These observations indicate that maternal Piwi, Aub and Ago3 play a critical role in the maintenance of chromatin structure and cell cycle progression during early embryogenesis, with compromised chromatin integrity as a possible cause of the observed mitotic defects. Our study demonstrates the essential function of PIWI proteins in the first phase of somatic development. © 2013 Elsevier Inc.