6,600 research outputs found
Precision laser range finder system design for Advanced Technology Laboratory applications
Preliminary system design of a pulsed precision ruby laser rangefinder system is presented which has a potential range resolution of 0.4 cm when atmospheric effects are negligible. The system being proposed for flight testing on the advanced technology laboratory (ATL) consists of a modelocked ruby laser transmitter, course and vernier rangefinder receivers, optical beacon retroreflector tracking system, and a network of ATL tracking retroreflectors. Performance calculations indicate that spacecraft to ground ranging accuracies of 1 to 2 cm are possible
Nuclear burst plasma injection into the magnetosphere and resulting spacecraft charging
The passage of debris from a high altitude ( 400 km) nuclear burst over the ionospheric plasma is found to be capable of exciting large amplitude whistler waves which can act to structure a collisionless shock. This instability will occur in the loss cone exits of the nuclear debris bubble, and the accelerated ambient ions will freestream along the magnetic field lines into the magnetosphere. Using Starfish-like parameters and accounting for plasma diffusion and thermalization of the propagating plasma mass, it is found that synchronous orbit plasma fluxes of high temperature electrons (near 10 keV) will be significantly greater than those encountered during magnetospheric substorms. These fluxes will last for sufficiently long periods of time so as to charge immersed bodies to high potentials and arc discharges to take place
“Who am I?” Personal Accounts of the Dementia Assessment Process and the Impact of the Dementia Label
There are competing models through which a dementia diagnosis can be understood, but what dominates the assessment process for dementia diagnosis is the medical model, which neglects the social, cultural, and political aspects of the diagnosis. In a Western society where value is ascribed to qualities associated with youth, such as good physical health, the rhetoric around older adults and dementia has long been dominated by stories of dependence and burden. Assuming them to be passive and unreliable, little research into the opinions of those diagnosed with dementia has been undertaken, but studies eliciting first-hand accounts suggest that the practice of diagnosis is inconsistent and often fails to meet the needs of the people receiving the diagnosis. Aiming to add depth to this research, four people aged over 65 with a dementia diagnosis were interviewed to evaluate the impact of socio-cultural discourse on their experience of being assessed for and living with a dementia diagnosis. Narrative analysis was then used, attending to the performative, descriptive, and contextual elements of the accounts. The study revealed the narrative abilities of people diagnosed with dementia and showed that hegemonic discourse on dementia alongside personal philosophies affect how the label is received and understood, and whether it is accepted or rejected. Participants also demonstrated value in interdependence, and a variety of post-diagnostic needs, reflecting the heterogeneity of those who receive the diagnosis. The implications of this study are then discussed, considering the impact that utilising the social model of disability could have on the treatment of people diagnosed with dementia
A novel laser ranging system for measurement of ground-to-satellite distances
A technique was developed for improving the precision of laser ranging measurements of ground-to-satellite distances. The method employs a mode-locked laser transmitter and utilizes an image converter tube equipped with deflection plates in measuring the time of flight of the laser pulse to a distant retroreflector and back. Samples of the outgoing and returning light pulses are focussed on the photocathode of the image converter tube, whose deflection plates are driven by a high-voltage 120 MHz sine wave derived from a very stable oscillator. From the relative positions of the images produced at the output phosphor by the two light pulses, it is possible to make a precise determination of the fractional amount by which the time of flight exceeds some large integral multiple of the period of the deflection sinusoid
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A viable mouse model of factor X deficiency provides evidence for maternal transfer of factor X.
BackgroundActivated factor X (FXa) is a vitamin K-dependent serine protease that plays a pivotal role in blood coagulation by converting prothrombin to thrombin. There are no reports of humans with complete deficiency of FX, and knockout of murine F10 is embryonic or perinatal lethal.ObjectiveWe sought to generate a viable mouse model of FX deficiency.MethodsWe used a socket-targeting construct to generate F10-knockout mice by eliminating F10 exon 8 (knockout allele termed F10(tm1Ccmt), abbreviated as '-'; wild-type '+'), and a plug-targeting construct to generate mice expressing a FX variant with normal antigen levels but low levels of FX activity [4-9% normal in humans carrying the defect, Pro343-->Ser, termed FX Friuli (mutant allele termed F10(tm2Ccmt), abbreviated as F)].ResultsF10 knockout mice exhibited embryonic or perinatal lethality. In contrast, homozygous Friuli mice [F10 (F/F)] had FX activity levels of approximately 5.5% (sufficient to rescue both embryonic and perinatal lethality), but developed age-dependent iron deposition and cardiac fibrosis. Interestingly, F10 (-/F) mice with FX activity levels of 1-3% also showed complete rescue of lethality. Further study of this model provides evidence supporting a role of maternal FX transfer in the embryonic survival.ConclusionsWe demonstrate that, while complete absence of FX is incompatible with murine survival, minimal FX activity as low as 1-3% is sufficient to rescue the lethal phenotype. This viable low-FX mouse model will facilitate the development of FX-directed therapies as well as investigation of the FX role in embryonic development
YOU’RE OBJECTING TO ME?: CHALLENGING JUDICIAL QUESTIONING
This Article examines the often seen and routinely unchallenged practice of judicial questioning. Part I covers the fundamental concept of judicial impartiality and the power of judges to question witnesses. Part II illustrates varied examples from both civil and criminal trials where judges crossed (or may have crossed) the line in questioning witnesses. Part III considers what trial counsel should do in the face of improper judicial questioning. Part IV explains how the failure to object to questioning significantly diminishes the likelihood of success on appeal. In the Conclusion, the Authors urge counsel to object whenever a judge’s questions appear likely to endanger their clients’ rights
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