19 research outputs found

    Mars Reconnaissance Orbiter Interplanetary Cruise Navigation

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    Carrying six science instruments and three engineering payloads, the Mars Reconnaissance Orbiter (MRO) is the first mission in a low Mars orbit to characterize the surface, subsurface, and atmospheric properties with unprecedented detail. After a seven-month interplanetary cruise, MRO arrived at Mars executing a 1.0 km/s Mars Orbit Insertion (MOI) maneuver. MRO achieved a 430 km periapsis altitude with the final orbit solution indicating that only 10 km was attributable to navigation prediction error. With the last interplanetary maneuver performed four months before MOI, this was a significant accomplishment. This paper describes the navigation analyses and results during the 210-day interplanetary cruise. As of August 2007 MRO has returned more than 18 Terabits of scientific data in support of the objectives set by the Mars Exploration Program (MEP). The robust and exceptional interplanetary navigation performance paved the way for a successful MRO mission

    Mars Reconnaissance Orbiter Aerobraking Daily Operations and Collision Avoidance

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    The Mars Reconnaissance Orbiter reached Mars on March 10, 2006 and performed a Mars orbit insertion maneuver of 1 km/s to enter into a large elliptical orbit. Three weeks later, aerobraking operations began and lasted about five months. Aerobraking utilized the atmospheric drag to reduce the large elliptical orbit into a smaller, near circular orbit. At the time of MRO aerobraking, there were three other operational spacecraft orbiting Mars and the navigation team had to minimize the possibility of a collision. This paper describes the daily operations of the MRO navigation team during this time as well as the collision avoidance strategy development and implementation

    The Gene Ontology knowledgebase in 2023

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    The Gene Ontology (GO) knowledgebase (http://geneontology.org) is a comprehensive resource concerning the functions of genes and gene products (proteins and noncoding RNAs). GO annotations cover genes from organisms across the tree of life as well as viruses, though most gene function knowledge currently derives from experiments carried out in a relatively small number of model organisms. Here, we provide an updated overview of the GO knowledgebase, as well as the efforts of the broad, international consortium of scientists that develops, maintains, and updates the GO knowledgebase. The GO knowledgebase consists of three components: (1) the GO-a computational knowledge structure describing the functional characteristics of genes; (2) GO annotations-evidence-supported statements asserting that a specific gene product has a particular functional characteristic; and (3) GO Causal Activity Models (GO-CAMs)-mechanistic models of molecular "pathways" (GO biological processes) created by linking multiple GO annotations using defined relations. Each of these components is continually expanded, revised, and updated in response to newly published discoveries and receives extensive QA checks, reviews, and user feedback. For each of these components, we provide a description of the current contents, recent developments to keep the knowledgebase up to date with new discoveries, and guidance on how users can best make use of the data that we provide. We conclude with future directions for the project

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Making sense of a student’s arrest for sexual assault: The need for talking and teaching in response to violent acts

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    Reports of sexual assault are frequently in the news and many news stories are about adolescents. Coverage of adolescent sexual assaults focuses on the perpetrator and the victim(s), without much attention to the community where the violence occurred. These events are magnified in the discourse of the #MeToo Movement. In reporting the crime, “the media and other social institutions (e.g. schooling) often turn trauma into a form of spectacle, in which the pain of others is commodified” and neglected (Zembylas, 2008, p. 8). Teachers who are invested in nurturing their students’ development likely respond emotionally when learning of students’ arrests for sexual assault. This study seeks to look beyond the “spectacle” to the experiences of two teachers who navigated these difficult moments with students while making sense their emotions through an intensive interview study (Lofland & Lofland, 1995). I address the following questions: 1) What were the emotional experiences of teachers who learned that students had been arrested for sexual assault? 2) How did teachers respond to these critical incidents? I will share how these teachers mediated the communal traumatic experiences through conversation and curriculum to make sense of the emotional, material, and political realities of these critical incidents

    ExoMars/TGO Science Orbit Design

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    This paper describes the development of the science orbit for the 2016 ESA/NASA collaborative ExoMars/Trace Gas Orbiter (TGO) mission. The initial requirements for the ExoMars/TGO mission simply described the science orbit as circular with a 400 km altitude and a 74 deg inclination. Over the past year, the JPL mission design team worked with the TGO science teams to refine the science orbit requirements and recommend an orbit that would be operationally feasible, easy to maintain, and most important allow the science teams to best meet their objectives

    Distributed north-vergent shear and flattening through Greater and Tethyan Himalayan rocks: Insights from metamorphic and strain data from the Dang Chu region, central Bhutan

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    In several places in the Himalaya, there are debates over the location of and defining criteria for the South Tibetan detachment (STD) system. Here, we attempt to resolve this debate in central Bhutan by interpreting temperature, pressure, finite strain, and shear-sense data from an 11-km-thick structural transect through the Dang Chu region. Raman spectroscopy on carbonaceous material and garnet-biotite thermometry define a gradual, structurally upward decrease from 600-700 degrees C to 400-500 degrees C, and structural data indicate pure shear-dominant (W-m <= 0.4), layer-normal flattening strain and north-vergent shearing distributed through most of the section. Our data, when combined with published data from central Bhutan, define gradual, structurally upward cooling and an upright pressure gradient that is 1.2-2.4 times lithostatic distributed between 0 and 11 km above the Main Central thrust (MCT). Transport-parallel lengthening varies between similar to 20%-110% at 2-5 km above the MCT and between similar to 5%-55% at 5-11 km above the MCT, and north-vergent shearing is distributed between 2 and 11 km above the MCT. These data rule out the presence of a discrete, normal-sense shear zone and instead illustrate distributed structural thinning accommodated by north-vergent shearing. The strain data allow for similar to 85 km of distributed north-vergent displacement, which may be related to differential southward transport during MCT emplacement. Alternatively, distributed shear may have been translated northward into the STD system in northern Bhutan. Timing constraints for shearing on the MCT and STD allow for both possibilities. Central Bhutan provides a case study for large-scale, distributed structural thinning, and highlights the diverse range of processes that accommodate tectonic denudation during orogenesis

    Primary Urethral Melanoma: A Case Report and Literature Review

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    Patients with localized urethral melanoma have a high risk of recurrence and poor disease-specific survival. Multi-disciplinary approach including surgery, radiation therapy, and chemotherapy/immunotherapy is needed to maximize survival. Current research efforts include investigation of novel tyrosine kinases as well as the combination of targeted therapies with immunotherapies in this population. Combinations may provide a synergistic effect to overcome various obstacles to disease response

    Temperature and strain gradients through Lesser Himalayan rocks and across the Main Central thrust, south central Bhutan: Implications for transport-parallel stretching and inverted metamorphism

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    In order to understand mass and heat transfer processes that operated during Himalayan orogenesis, we collected temperature, finite and incremental strain, and kinematic vorticity data through a 5 km thickness of Lesser and Greater Himalayan rocks in southern Bhutan. This transect crosses two major shear zones, the Main Central thrust (MCT) and Shumar thrust (ST). Raman spectroscopy on carbonaceous material and garnet-biotite thermometry are integrated with deformation temperatures from quartz petrofabrics. These data define inverted field gradients that correspond in structural position with the MCT and ST, which are separated by sections in which temperatures remain essentially constant. Temperatures increase from similar to 400-500 degrees C to similar to 700-750 degrees C between 675m below and 200m above the MCT. This defines a 269 +/- 44 degrees C/km inverted gradient, interpreted to have formed via high-magnitude (similar to 100-250 km) shearing on a discrete MCT zone delineated by the limits of inverted metamorphism. Temperatures increase from similar to 300-400 degrees C to similar to 400-530 degrees C across the ST, which is attributed to differences in maximum burial depth of hanging wall and footwall rocks. Strain and vorticity data indicate that Lesser and Greater Himalayan rocks were deformed by layer-normal flattening. Transport-parallel lengthening and foliation-normal shortening increase from 38-71% to 36-49%, respectively, between 2.3 and 1.0 km below the MCT. The MCT acted as a "stretching fault," with translation on the order of hundreds of kilometers accompanied by transport-parallel stretching of footwall and hanging wall rocks on the order of tens of kilometers. This demonstrates that stretching accommodated between major shear zones can make a significant contribution to cumulative mass transfer

    Mars Reconnaissance Orbiter Navigation

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    Mars Reconnaissance Orbiter will launch in August 2005 at Cape Canaveral Air Force Station. The heavyweight spacecraft will use a Lockheed-Martin Atlas V-401 launch vehicle. It will be the first mission in a low Mars Orbit to characterize the surface, subsurface, and atmospheric properties. The intensive science operation imposes a great challenge for Navigation to satisfy the stringent requirements. This paper describes navigation key requirements, major challenges, and the sophisticated dynamic modeling. It also details navigation strategy and processes for various mission phases. Mars Reconnaissance Orbiter will return significant amount of scientific data in support of the objectives set by the Mars Exploration Program. A robust and precise navigation is the key to the success of this mission
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