1,512 research outputs found
Collision Avoidance by Speed Change
Abstract: Farrell JL. (2013). Collision avoidance by speed change. International Journal of Unmanned Systems Engineering. 1(1): 1-8. With UAV usage increasing at rapid rates, a corresponding increase in attention to collision avoidance is clearly warranted. A strategy introduced more than ten years ago, being pursued in an investigation by Ohio University with NASA sponsorship, is supported by programming efforts that address dangerous scenarios. For aircraft that would collide if allowed to remain in their existing flight paths, conflict resolution can be provided by changing speed. Results are provided herein for a variety of conditions. The method requires no large budgets, nor new inventions; existing equipment (GPS/GNSS, ModeS) is sufficient with extension of known techniques (double differencing) to tracking. The approach offers enormous advantages in safety, versatility, autonomy, and all aspects of aircraft navigation performance. The theory has already been described in references cited; presentation of computational results here is followed by operational considerations. Preliminary flight testing recently reported elsewhere (Duan, Uijt de Haag, and Farrell; DASC 12, October 2012, Williamsburg, VA) raised prospects for reducing uncertainty volume (predicted position at time of closest approach) from hundreds of meters (due to m/s velocity uncertainty) to a few meters (from cm/s velocity accuracy)
Multi-centre retrospective study of long-term outcomes following traumatic elbow luxation in 37 dogs
Is Reconstruction of the Sella Necessary to Prevent Optic Chiasm Prolapse and Cerebrospinal Fluid Leakage Following Endoscopic Resection of Pituitary Macroadenomas?
Visual compromise is a common presentation of pituitary macroadenomas and is related to direct optic nerve and chiasm compression. Although the extent of visual recovery following treatment depends on the duration and severity of the visual compromise, the majority of patients experience gradual improvement in their vision. Delayed visual deterioration following treatment is typically related to either tumor recurrence or radiation-induced optic neuropathy, although visual worsening due to prolapse of the optic apparatus into a secondary empty sella has rarely been reported. In 1968, Guiot reported the first a case of reversible visual deterioration associated with optic chiasm prolapse following resection of a large pituitary macroadenoma (Guiot). Based on their observations, Guiot and collaborators recommended that a “prop” be placed in the sella at the time of transsphenoidal pituitary adenoma resection to prevent progressive herniation of the optic structures. Similarly, Hardy coined the term “preventive chiasmopexy” to describe filling of the sella cavity with autologous tissue such as muscle or fat following resection of large tumors to prevent this herniation phenomenon. While optic chiasm prolapse with associated visual deterioration appears to represent a rare occurrence, its true incidence and pathophysiological basis remain uncertain. Reconstruction of the sella with autologous tissues is also widely employed as a means to prevent postoperative cerebrospinal fluid leakage with these tissues typically harvested from a secondary operative site such as the abdomen. Although not frequently reported in the pituitary literature, complications of abdominal fat graft harvest include hematoma and seroma formation as well as infection with an incidence ranging from 1-7%. At our institution, we do not routinely perform dural reconstruction following transsphenoidal resection of pituitary macroadenomas using adipose tissue to prevent cerebrospinal fluid leakage or optic chiasm prolapse. In this study, we sought to determine the incidence of optic chiasm prolapse into the sellar defect by determining the radiographic position of the optic chiasm following surgery and incidence of delayed visual deterioration.
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Muskellunge and Northern Pike Ecology and Management: Important Issues and Research Needs
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141909/1/fsh0258.pd
The Impact of Depression, Anxiety and Personality Disorders on the Outcome of Patients with Functional Limb Weakness – Individual Patient Data Meta-Analysis
Objective: Psychiatric comorbidities such as depression, anxiety, and personality disorders are common in patients with functional limb weakness/paresis (FND-par). The impact of these conditions on the prognosis of FND-par has not been systematically reviewed. The aim of this study was to identify a potential prognostic effect of comorbid depression, anxiety, and/or personality disorder on prognosis in patients with FND-par. Methods: A systematic review was performed to identify studies that reported measures of baseline depression, anxiety, and/or personality disorder, and physical disability. An individual patient data meta-analysis was subsequently performed. Results: Eight studies comprising 348 individuals were included (7 prospective cohorts; 1 case-control study). There was heterogeneity in sample size, follow-up duration, and treatment modality. Depression and anxiety were present in 51.4% and 53.0% of FND-par patients, respectively. In individuals whose FND-par improved, there was no significant difference between those with versus without depression (52.6% vs 47.4%, p = 0.69) or those with versus without anxiety (50.3% vs 49.7%, p = 0.38). Meta-analysis showed no clear impact of baseline depression or anxiety per se [pooled OR for depression 0.85 (95%CI 0.50–1.45; p = 0.40) and anxiety 0.84 (95%CI 0.51–1.38; p = 0.91)]; and of depression or anxiety severity [pooled OR for depression 1.23 (95%CI 0.63–2.39; p = 0.91) and anxiety 1.40 (95%CI 0.70–2.78; p = 0.58)] on FND-par outcome. Insufficient data were available to assess the impact of personality disorders. Conclusion: We found no evidence that depression or anxiety influenced outcome in FND-par. Large-scale, prospective studies in FND-par, and other FND subtypes, are needed to fully contextualize the impact of concurrent mental health concerns on outcomes.</p
Phase I Study of Ipilimumab Combined with Whole Brain Radiation Therapy or Radiosurgery for Melanoma Patients with Brain Metastases
Purpose: We performed a phase I study to determine the maximum tolerable dose (MTD) and safety of ipilimumab with stereotactic radiosurgery (SRS) or whole brain radiotherapy (WBRT) in patients with brain metastases (BM) from melanoma.
Methods: Based on intracranial (IC) disease burden, patients were treated with WBRT (Arm A) or SRS (Arm B). Ipilimumab starting dose was 3 mg/kg (every 3 weeks, starting on day 3 of WBRT or 2 days after SRS). Ipilimumab was escalated to 10 mg/kg using a two-stage, 3+3 design. The primary endpoint was to determine the MTD of ipilimumab combined with radiotherapy. Secondary endpoints were overall survival (OS), IC and extracranial (EC) control, progression free survival (PFS), and toxicity. This trial is regis- tered with ClinicalTrials.gov, number NCT01703507.
Results: Characteristics of the 16 patients enrolled between 2011 and 2014 were: mean age, 60; median BM, 2 (1 to \u3e10); number with EC disease, 13 (81%). Treatment included WBRT (n=5), SRS (n=11), ipilimumab 3mg/kg (n=7), 10 mg/kg (n=9). Median follow-up was 8 months (Arm A) and 10.5 months (Arm B). There were 21 grade 1-2 neuro- toxic effects with no dose-limiting toxicities (DLTs). One patient experienced grade 3 neurotoxicity prior to ipilimumab administration. Ten additional grade 3 toxicities were reported with gastrointestinal (n=5, 31%) as the most common. There were no grade 4/5 toxicities. Median PFS and OS, respectively, in Arm A were 2.5 months and 8 months, and in Arm B were 2.1 months and not reached.
Conclusion: Concurrent ipilimumab 10 mg/kg with SRS is safe. The WBRT arm was closed early due to slow accrual, but demonstrated safety with ipilimumab 3 mg/kg. No patient experienced DLT. Larger studies with ipilimumab 10 mg/kg and SRS are warranted
Ensuring phenotyping algorithms using national electronic health records are FAIR:Meeting the needs of the cardiometabolic research community
Phenotyping algorithms enable the extraction of clinically-relevant information (such as diagnoses, prescription information, or a blood pressure measurement) from electronic health records for use in research. They have enormous potential and wide-ranging utility in research to improve disease understanding, health, and healthcare provision. While great progress has been achieved over the past years in standardising how genomic data are represented and curated (e.g. VCF files for variants), phenotypic data are significantly more fragmented and lack a common representation approach. This lack of standards creates challenges, including a lack of comparability, transparency and reproducibility, and limiting the subsequent use of phenotyping algorithms in other research studies. The FAIR guiding principles for scientific data management and stewardship state that digital assets should be findable, accessible, interoperable and reusable, yet the current lack of phenotyping algorithm standards means that phenotyping algorithms are not FAIR. We have therefore engaged with the community to address these challenges, including defining standards for the reporting and sharing of phenotyping algorithms. Here we present the results of our engagement with the community to identify and explore their requirements and outline our recommendations to ensure FAIR phenotyping algorithms are available to meet the needs of the cardiometabolic research community
Ensuring phenotyping algorithms using national electronic health records are FAIR:Meeting the needs of the cardiometabolic research community
Phenotyping algorithms enable the extraction of clinically-relevant information (such as diagnoses, prescription information, or a blood pressure measurement) from electronic health records for use in research. They have enormous potential and wide-ranging utility in research to improve disease understanding, health, and healthcare provision. While great progress has been achieved over the past years in standardising how genomic data are represented and curated (e.g. VCF files for variants), phenotypic data are significantly more fragmented and lack a common representation approach. This lack of standards creates challenges, including a lack of comparability, transparency and reproducibility, and limiting the subsequent use of phenotyping algorithms in other research studies. The FAIR guiding principles for scientific data management and stewardship state that digital assets should be findable, accessible, interoperable and reusable, yet the current lack of phenotyping algorithm standards means that phenotyping algorithms are not FAIR. We have therefore engaged with the community to address these challenges, including defining standards for the reporting and sharing of phenotyping algorithms. Here we present the results of our engagement with the community to identify and explore their requirements and outline our recommendations to ensure FAIR phenotyping algorithms are available to meet the needs of the cardiometabolic research community
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