334 research outputs found
Space transportation systems, launch systems, and propulsion for the Space Exploration Initiative: Results from Project Outreach
A number of transportation and propulsion options for Mars exploration missions are analyzed. As part of Project Outreach, RAND received and evaluated 350 submissions in the launch vehicle, space transportation, and propulsion areas. After screening submissions, aggregating those that proposed identical or nearly identical concepts, and eliminating from further consideration those that violated known physical princples, we had reduced the total number of viable submissions to 213. In order to avoid comparing such disparate things as launch vehicles and electric propulsion systems, six broad technical areas were selected to categorize the submissions: space transportation systems; earth-to-orbit (ETO) launch systems; chemical propulsion; nuclear propulsion; low-thrust propulsion; and other. To provide an appropriate background for analyzing the submissions, an extensive survey was made of the various technologies relevant to the six broad areas listed above. We discuss these technologies with the intent of providing the reader with an indication of the current state of the art, as well as the advances that might be expected within the next 10 to 20 years
Identification of Ajnala skeletal remains using multiple forensic anthropological methods and techniques: a bioarchaeological report.
Fragmented and badly damaged commingled human remains present a tough challenge for their identification pursuits in forensic anthropology. Thousands of unknown human remains along with items of contextual identity, reportedly belonging to 282 Indian sepoys killed in 1857, were exhumed non-scientifically from a disused ancient well at Ajnala (Amritsar, India). In this manuscript, the non-scientific excavation of unknown human remains from the abandoned well, their forensic anthropological strategies for identification purposes, challenges being faced and future possibilities of their biological profiling have been discussed. Multiple methods and techniques like anthropological examinations, odontological profiling, radiological analyses, stable isotope and mitochondrial DNA (mtDNA) analyses were applied to few bones and teeth collected from the Ajnala skeletal assemblage. Though majority of studied bones and teeth were found belonging to adult males, very few of them had morphological, osteological and molecular features questioning the authenticity and validity of the written records. Due to certain ambiguous findings or gaps observed between the anthropological analyses of the Ajnala skeletal remains and the reported versions about their affiliations; certain advanced radiological, chemical and molecular techniques were applied to estimate their probable age, sex and populational affinity. The obtained radiological, isotopic and molecular signatures of the remains were compared with the available databases to estimate their affinity with the individuals of geographic area to whom the remains reportedly belonged to. The maternally inherited mtDNA haplogroup assignments, and stable isotope analysis of carbon and oxygen suggested that the studied human remains belonged to the individuals from West Bengal, Bihar, Odisha, Awadh (presently in Uttar Pradesh) and parts of Meghalaya and Manipur as potential regions of their geographic identity and thus, attributing the victims to be non-local to the site. However, merely on the basis of forensic anthropological examinations of very few bones and teeth (collected out of a huge collection of thousands of bones and teeth); it would be just an unqualified and sweeping conclusion to claim their identity as adult or non-adult, male or female, local or non-local, victims of 1857 mass killings or to the victims of ceremonial sacrifices or criminal activities committed in the past. A sufficient number of bones and teeth along with items of personal identity needs to be examined with multiple scientific techniques to arrive at some valid conclusions about their biological identity
Large Subcapsular Liver Hematoma Following Single-Incision Laparoscopic Cholecystectomy
Single incision laparoscopic cholecystectomy may pose significant risks that warrant operative caution. The authors suggest that single incision laparoscopic surgery be compared to the “gold-standard” laparoscopic procedure to further elucidate benefits and complications of this novel technique
Impacts of urban real-world labs: Insights from a co-evaluation process informed by structuration theory in Wuppertal-Mirke
To address the evaluation of the societal impact of real-world labs, we present a framework developed for the analysis of structure-agency dynamics: structuration theory. Using this tool on a neighbourhood level, we assess the outcomes of six projects on co-productive city-making.
Ways of evaluating the societal impact of real-world labs as a transdisciplinary and transformative research format are under discussion. We present an evaluation approach rooted in structuration theory, with a focus on structure-agency dynamics at the science-society interface. We applied the theory with its four modalities (interpretation schemes, norms, allocative and authoritative resources) to the case of the Mirke neighbourhood in Wuppertal, Germany. Six projects promoted the capacity for co-productive city-making. The effects of the projects were jointly analysed in a co-evaluation process. Previously proposed subcategories of the modalities as an empirical operationalisation were tested and confirmed as being applicable. Five new subcategories were generated. The use of the modalities seems appropriate for co-evaluation processes. The tool is practical, focused on real-world effects, and suitable for transdisciplinary interpretation processes. We encourage further empirical testing of the tool, as well as development of the subcategories
Impacts of urban real-world labs
Ways of evaluating the societal impact of real-world labs as a transdisciplinary and transformative research format are under discussion. We present an evaluation approach rooted in structuration theory, with a focus on structure-agency dynamics at the science-society interface. We applied the theory with its four modalities (interpretation schemes, norms, allocative and authoritative resources) to the case of the Mirke neighbourhood in Wuppertal, Germany. Six projects promoted the capacity for co-productive city-making. The effects of the projects were jointly analysed in a co-evaluation process. Previously proposed subcategories of the modalities as an empirical operationalisation were tested and confirmed as being applicable. Five new subcategories were generated. The use of the modalities seems appropriate for co-evaluation processes. The tool is practical, focused on real-world effects, and suitable for transdisciplinary interpretation processes. We encourage further empirical testing of the tool, as well as development of the subcategories.</p
Factors associated with chest injuries to front seat occupants in frontal impacts
Objective: Improving crash protection for older car occupants is a matter of urgency since the number of older car users is forecast to grow dramatically over the next two decades. The thorax is particularly vulnerable in older occupants, and this study aimed to provide real-world in-depth analysis of factors contributing to chest
injuries in frontal impacts involving European cars. Methods: Real world crash injury data were interrogated, focusing on cars with current restraint components. The research examined belted front-seat occupants in frontal impacts where air bags, pretensioners and load limiters were present. Results: The chest was the most often injured body region at AIS 2+, 3+ and 4+ injury levels. The rate of AIS 2+ and AIS 3+ chest injuries was highest among elderly occupants and lowest among young occupants, and elderly occupants sustained proportionally more severe chest injuries in low/moderate speed impacts compared to young and middle-aged occupants. However, it should be noted that rates of AIS 2 chest injury were also significantly higher for middle-aged occupants compared to the young. The front passenger seat was shown to be more often associated with significant chest injury than the driver seat. The higher proportion of elderly
female occupants was postulated as a reason for this. Skeletal injury was the most frequent type of AIS 2+ chest injury and the rate of injury for elderly occupants with such injuries was higher than for young and middle-aged occupants. With the increase in the number of rib fractures, the risk of pulmonary complications and organ injuries tended to increase. The major cause of chest injury was identified as restraining loads transmitted to the chest via the seat belt. The absence of intrusion in the majority of cases, suggests an opportunity for the restraint
system to better manage the crash pulse. Not only for elderly occupants but for those who are middle-aged as well. Conclusions: This study shows the necessity for safety interventions, through new vehicle crashworthiness systems to improve chest protection especially for middle aged and elderly car occupants. Deployment of appropriate injury risk criteria, use of an appropriate dummy thorax, development of a low energy restraint test, and the development of more adaptive restraints have been discussed as possible solutions to the problem
The LEADING Guideline:Reporting Standards for Expert Panel, Best-Estimate Diagnosis, and Longitudinal Expert All Data (LEAD) Studies.
Accurate assessments of symptoms and diagnoses are essential for health research and clinical practice but face many challenges. The absence of a single error-free measure is currently addressed by assessment methods involving experts reviewing several sources of information to achieve a more accurate or best-estimate assessment. Three bodies of work spanning medicine, psychiatry, and psychology propose similar assessment methods: The Expert Panel, the Best-Estimate Diagnosis, and the Longitudinal Expert All Data (LEAD). However, the quality of such best-estimate assessments is typically very difficult to evaluate due to poor reporting of the assessment methods and when it is reported, the reporting quality varies substantially. Here we tackle this gap by developing reporting guidelines for such studies, using a four-stage approach: 1) drafting reporting standards accompanied by rationales and empirical evidence, which were further developed with a patient organization for depression, 2) incorporating expert feedback through a two-round Delphi procedure, 3) refining the guideline based on an expert consensus meeting, and 4) testing the guideline by i) having two researchers test it and ii) using it to examine the extent previously published articles report the standards. The last step also demonstrates the need for the guideline: 18 to 58% (Mean = 33%) of the standards were not reported across fifteen randomly selected studies. The LEADING guideline comprises 20 reporting standards related to four groups: The Longitudinal design; the Appropriate data; the Evaluation - experts, materials, and procedures; and the Validity group. We hope that the LEADING guideline will be useful in assisting researchers in planning, reporting, and evaluating research aiming to achieve best-estimate assessments. Open data (Delphi surveys 1 and 2), code (analyses), and material (surveys): https://osf.io/fkv4b
Dense Antihydrogen: Its Production and Storage to Envision Antimatter Propulsion
We discuss the possibility that dense antihydrogen could provide a path
towards a mechanism for a deep space propulsion system. We concentrate at
first, as an example, on Bose-Einstein Condensate (BEC) antihydrogen. In a
Bose-Einstein Condensate, matter (or antimatter) is in a coherent state
analogous to photons in a laser beam, and individual atoms lose their
independent identity. This allows many atoms to be stored in a small volume. In
the context of recent advances in producing and controlling BECs, as well as in
making antihydrogen, this could potentially provide a revolutionary path
towards the efficient storage of large quantities of antimatter, perhaps
eventually as a cluster or solid.Comment: 12 pages, 3 figure
Rivaroxaban for Venous Thromboembolism Prophylaxis in Abdominoplasty: A Multicenter Experience
BACKGROUND: Abdominoplasty, a commonly performed aesthetic procedure, is considered to have an increased risk of venous thromboembolism (VTE) events. At present, routine VTE chemoprophylaxis following abdominoplasty remains controversial.
OBJECTIVES: This study evaluates the authors' experience with rivaroxaban, an oral Factor Xa inhibitor, for VTE prophylaxis in abdominoplasty patients.
METHODS: A retrospective case series was conducted. All patients who underwent abdominoplasty and received rivaroxaban were included. The prophylactic dose was 10 mg daily for 7 days, beginning 12 hours postoperatively. Patient demographics, comorbidities, and type of surgery were recorded. The primary outcome measured was hematologic complication, including VTE, hematoma requiring operative evacuation, and need for blood transfusion.
RESULTS: From September 2012 until July 2014, 132 patients (122 women and 10 men) underwent abdominoplasty surgery and received rivaroxaban postoperatively. Mean patient age was 43.7 years, and mean body mass index was 27.1. One hundred twenty-five patients also underwent abdominal muscle plication. Eleven patients underwent a fleur de lis vertical skin resection component. One hundred patients underwent concomitant abdominal liposuction, while 79 patients also had back liposuction. Only 1 patient had a symptomatic VTE event. Three patients had a hematoma requiring operative evacuation, and all went on to heal without sequelae. Two patients received a blood transfusion for anemia during their course of rivaroxaban.
CONCLUSIONS: Oral rivaroxaban administration for chemoprophylaxis in abdominoplasty patients is safe, with low rates of symptomatic VTE and hematoma formation. The authors continue routine use of the medication for patients at increased risk for VTE events. LEVEL OF EVIDENCE 4: Risk
K⊂{[Fe(Tp)(CN)][Co(Tp)][Co(Tp)]}: a neutral soluble model complex of photomagnetic Prussian blue analogues
Straightforward access to a new cyanide-bridged {FeCo} “molecular box” containing a potassium ion, namely K⊂{[Fe(Tp)(CN)][Co(Tp)][Co(Tp)]} (1) (with Tp and Tp = tris- and tetrakis(pyrazolyl)borate, respectively), is provided, alongside its full characterisation. A detailed analysis of the molecular structure (X-ray diffraction, mass spectrometry, NMR spectroscopy) and electronic properties (EPR spectroscopy, SQUID magnetometry, UV/Vis spectroscopy, cyclic voltammetry) reveals that 1 shows slow magnetic relaxation and a remarkable photomagnetic effect at low temperature which is reminiscent of some FeCo Prussian Blue Analogues (PBAs), and is ascribed to a photo-induced electron transfer. However, in contrast with these inorganic polymers, the overall neutral compound 1 is soluble and remarkably stable in organic solvents such as CH2Cl2. Moreover, 1 shows interesting redox versatility, with electrochemical experiments revealing the possible access to six stable redox states
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