1,990 research outputs found
Rapid Trajectory Optimization for the ARES I Launch Vehicle
A simplified ascent trajectory optimization procedure has been developed with application to NASA's proposed Ares I launch vehicle. In the interest of minimizing bending loads and ensuring safe separation of the first-stage solid rocket motor, the vehicle is con- strained to follow a gravity-turn trajectory. This reduces the design space to just two free parameters, the pitch rate after a short vertical rise phase to clear the launch pad, and initial launch azimuth. The pitch rate primarily controls the in-plane parameters (altitude, speed, flight path angle) of the trajectory whereas the launch azimuth primarily controls the out-of-plane portion (velocity heading.) Thus, the optimization can be mechanized as two one-dimensional searches that converge quickly and reliably. The method is compared with POST-optimized trajectories to verify its optimality
Launch Vehicle Abort Analysis for Failures Leading to Loss of Control
Launch vehicle ascent is a time of high risk for an onboard crew. There is a large fraction of possible failures for which time is of the essence and a successful abort is possible if the detection and action happens quickly enough. This paper focuses on abort determination based on data already available from the Guidance, Navigation, and Control system. This work is the result of failure analysis efforts performed during the Ares I launch vehicle development program. The two primary areas of focus are the derivation of abort triggers to ensure that abort occurs as quickly as possible when needed, but that false aborts are avoided, and evaluation of success in aborting off the failing launch vehicle
Multigenerational Modeling of Money Management
This study is about implicit financial socialization within families. It specifically examines how parental modeling facilitates the intergenerational transmission of healthy financial behaviors. This qualitative, multi-generational, multi-site study begins to answer the following research question: What financial behaviors are parents modeling for their children? The sample for this study (N=115) included 90 undergraduate students (ages 18-30) enrolled in family finance classes at three U.S. universities, 18 of their parents, and 7 of their grandparents. Using a team-based approach to qualitative data collection, analysis, and coding, four consensus themes related to parental financial modeling were distilled: (1) Working for a living (2) Managing money wisely (3) The importance of generosity and (4) Sacrificing for children. These ideas can be used by parents, family life educators, financial therapists, and others to help improve the quality of financial socialization within families
DICER1 tumor predisposition syndrome: An evolving story initiated with the pleuropulmonary blastoma
DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation
Rest Pain and Movement-Evoked Pain as Unique Constructs in Hip and Knee Replacements
OBJECTIVE: There is limited information about the extent to which the association between preoperative and chronic postoperative pain is mediated via pain‐on‐movement or pain‐at‐rest. We explored these associations in patients undergoing total hip replacement (THR) and total knee replacement (TKR). METHODS: A total of 322 and 316 patients receiving THR and TKR, respectively, were recruited into a single‐center UK cohort (Arthroplasty Pain Experience) study. Preoperative, acute postoperative, and 12‐month pain severity was measured using self‐reported pain instruments. The association between preoperative/acute pain and chronic postoperative pain was investigated using structural equation modeling (SEM). RESULTS: Patients with high levels of preoperative pain were more likely to report chronic pain after THR (β = 0.195, P = 0.02) and TKR (β = 0.749, P < 0.0001). Acute postoperative pain‐on‐movement was not associated with chronic pain after TKR or THR after adjusting for preoperative pain; however, acute pain‐at‐rest was associated with chronic pain after THR (β = 0.20, P < 0.0002) but not TKR after adjusting for preoperative pain. Analysis of pain‐at‐rest and pain‐on‐movement highlighted differences between THR and TKR patients. Chronic pain‐at‐rest after THR was weakly associated with pain‐at‐rest during the preoperative (β = 0.11, P = 0.068) and acute postoperative period (β = 0.21, P < 0.0001). In contrast, chronic pain‐on‐movement after TKR was strongly associated with the severity of pain‐on‐movement during the preoperative period (β = 0.51, P = 0.001). CONCLUSION: SEM illustrated the different patterns of association between measures of pain over time in patients undergoing THR and TKR for osteoarthritis. These findings highlight the importance of future work that explores the mechanisms underlying pain‐on‐movement and pain‐at‐rest
Secretome survey of human plexiform neurofibroma derived schwann cells reveals a secreted form of the RARRES1 protein.
To bring insights into neurofibroma biochemistry, a comprehensive secretome analysis was performed on cultured human primary Schwann cells isolated from surgically resected plexiform neurofibroma and from normal nerve tissue. Using a combination of SDS-PAGE and high precision LC-MS/MS, 907 proteins were confidently identified in the conditioned media of Schwann cell cultures combined. Label free proteome profiling revealed consistent release of high levels of 22 proteins by the four biological replicates of NF1 Schwann cell cultures relative to the two normal Schwann cell cultures. Inversely, 9 proteins displayed decreased levels in the conditioned media of NF1 relative to normal Schwann cells. The proteins with increased levels included proteins involved in cell growth, angiogenesis and complement pathway while proteins with decreased levels included those involved in cell adhesion, plasminogen pathway and extracellular matrix remodeling. Retinoic acid receptor responder protein-1 (RARRES1), previously described as an integral membrane tumor suppressor, was found exclusively secreted by NF1 Schwann cells but not by normal Schwann cells. All-trans retinoic acid modulated secretion of RARRES1 in a dose dependent manner. This study shows altered secretion of key proteins in NF1 derived Schwann cells. The potential implication of these proteins in neurofibroma biology is discussed
Trajectories of Pain and Function after Primary Hip and Knee Arthroplasty:The ADAPT Cohort Study
BACKGROUND AND PURPOSE:Pain and function improve dramatically in the first three months after hip and knee arthroplasty but the trajectory after three months is less well described. It is also unclear how pre-operative pain and function influence short- and long-term recovery. We explored the trajectory of change in function and pain until and beyond 3-months post-operatively and the influence of pre-operative self-reported symptoms. METHODS:The study was a prospective cohort study of 164 patients undergoing primary hip (n = 80) or knee (n = 84) arthroplasty in the United Kingdom. Self-reported measures of pain and function using the Western Ontario and McMaster Universities Osteoarthritis index were collected pre-operatively and at 3 and 12 months post-operatively. Hip and knee arthroplasties were analysed separately, and patients were split into two groups: those with high or low symptoms pre-operatively. Multilevel regression models were used for each outcome (pain and function), and the trajectories of change were charted (0-3 months and 3-12 months). RESULTS:Hip: Most improvement occurred within the first 3 months following hip surgery and patients with worse pre-operative scores had greater changes. The mean changes observed between 3 and twelve months were statistically insignificant. One year after surgery, patients with worse pre-operative scores had post-operative outcomes similar to those observed among patients with less severe pre-operative symptoms. Knee: Most improvement occurred in the first 3 months following knee surgery with no significant change thereafter. Despite greater mean change during the first three months, patients with worse pre-operative scores had not 'caught-up' with those with less severe pre-operative symptoms 12 months after their surgery. CONCLUSION:Most symptomatic improvement occurred within the first 3 months after surgery with no significant change between 3-12 months. Further investigations are now required to determine if patients with severe symptoms at the time of their knee arthroplasty have a different pre-surgical history than those with less severe symptoms and if they could benefit from earlier surgical intervention and tailored rehabilitation to achieve better post-operative patient-reported outcomes
Profiles of Disruptive Behavior Across Early Childhood: Contributions of Frustration Reactivity, Physiological Regulation, and Maternal Behavior
Disruptive behavior, including aggression, defiance, and temper tantrums, typically peaks in early toddlerhood and decreases by school entry; however, some children do not show this normative decline. The current study examined disruptive behavior in 318 boys and girls at 2, 4, and 5 years of age and frustration reactivity, physiological regulation, and maternal behavior in the laboratory at 2 years of age. A latent profile analysis resulted in 4 longitudinal profiles of disruptive behavior, which were differentiated by interactions between reactivity, regulation, and maternal behavior. A high profile was associated with high reactivity combined with high maternal control or low regulation combined with low maternal control. Results are discussed from a developmental psychopathology perspective
Training in Trauma-Informed Care (TIC): An Evidence-Based Practice Project
This Evidence-Based Practice (EBP) project examined the following question: What are the characteristics and effectiveness of trauma-informed care (TIC) training on the performance of health professionals and organizations who provide services to populations who have experienced trauma (traumatic events or ACE)
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