Differential Very Long Baseline Interferometry (delta VLBI) spacecraft tracking system demonstration. Part 2: Data acquisition and processing

A set of experiments in the use of Differential Very Long Baseline Interferometry (delta VLBI) for spacecraft navigation were completed. Data using both Voyager spacecraft and a single quasar were acquired during the Jupiter encounter time period. The data were processed and analyzed to assess the navigation accuracy of delta VLBI. The data reduction and techniques for assessing data quality and consistency are discussed

Spectral Analysis of Protein-Protein Interactions in Drosophila melanogaster

Within a case study on the protein-protein interaction network (PIN) of Drosophila melanogaster we investigate the relation between the network's spectral properties and its structural features such as the prevalence of specific subgraphs or duplicate nodes as a result of its evolutionary history. The discrete part of the spectral density shows fingerprints of the PIN's topological features including a preference for loop structures. Duplicate nodes are another prominent feature of PINs and we discuss their representation in the PIN's spectrum as well as their biological implications.Comment: 9 pages RevTeX including 8 figure

Standards of resuscitation during inter-hospital transportation: the effects of structured team briefing or guideline review - A randomised, controlled simulation study of two micro-interventions

<p>Abstract</p> <p>Background</p> <p>Junior physicians are sometimes sent in ambulances with critically ill patients who require urgent transfer to another hospital. Unfamiliar surroundings and personnel, time pressure, and lack of experience may imply a risk of insufficient treatment during transportation as this can cause the physician to loose the expected overview of the situation. While health care professionals are expected to follow complex algorithms when resuscitating, stress can compromise both solo-performance and teamwork.</p> <p>Aim</p> <p>To examine whether inter-hospital resuscitation improved with a structured team briefing between physician and ambulance crew in preparation for transfer vs. review of resuscitation guidelines. The effect parameters were physician team leadership (requesting help, delegating tasks), time to resuscitation key elements (chest compressions, defibrillation, ventilations, medication, or a combination of these termed "the first meaningful action"), and hands-off ratio.</p> <p>Methods</p> <p>Participants: 46 physicians graduated within 5 years. Design: A simulation intervention study with a control group and two interventions (structured team briefing or review of guidelines). Scenario: Cardiac arrest during simulated inter-hospital transfer.</p> <p>Results</p> <p>Forty-six candidates participated: 16 (control), 13 (review), and 17 (team briefing). Reviewing guidelines delayed requesting help to 162 seconds, compared to 21 seconds in control and team briefing groups (p = 0.021). Help was not requested in 15% of cases; never requesting help was associated with an increased hands-off ratio, from 39% if the driver's assistance was requested to 54% if not (p < 0.01). No statistically significant differences were found between groups regarding time to first chest compression, defibrillation, ventilation, drug administration, or the combined "time to first meaningful action".</p> <p>Conclusion</p> <p>Neither review nor team briefing improved the time to resuscitation key elements. Review led to an eight-fold increase in the delay to requesting help. The association between never requesting help and an increased hands-off ratio underpins the importance of prioritising available resources. Other medical and non-medical domains have benefited from the use of guidelines reviews and structured team briefings. Reviewing guidelines may compromise the ability to focus on aspects such as team leading and delegating tasks and warrants the need for further studies focusing on how to avoid this cognitive impairment.</p

Correlations of record events as a test for heavy-tailed distributions

A record is an entry in a time series that is larger or smaller than all previous entries. If the time series consists of independent, identically distributed random variables with a superimposed linear trend, record events are positively (negatively) correlated when the tail of the distribution is heavier (lighter) than exponential. Here we use these correlations to detect heavy-tailed behavior in small sets of independent random variables. The method consists of converting random subsets of the data into time series with a tunable linear drift and computing the resulting record correlations.Comment: Revised version, to appear in Physical Review Letter

The merging/AGN connection: A case for 3D spectroscopy

We discuss an ongoing study of the connection between galaxy merging/interaction and AGN activity, based on integral field spectroscopy. We focus on the search for AGN ionization in the central regions of mergers, previously not classified as AGNs. We present here the science case, the current status of the project, and plans for future observations.Comment: 4 pages, 3 figure, Euro3D Science Workshop, Cambridge, May 2003, AN, accepte

Universality of Electron Mobility in LaAlO3_3/SrTiO3_3 and bulk SrTiO3_3

Metallic LaAlO$_3$/SrTiO$_3$ (LAO/STO) interfaces attract enormous attention, but the relationship between the electron mobility and the sheet electron density, $n_s$, is poorly understood. Here we derive a simple expression for the three-dimensional electron density near the interface, $n_{3D}$, as a function of $n_s$ and find that the mobility for LAO/STO-based interfaces depends on $n_{3D}$ in the same way as it does for bulk doped STO. It is known that undoped bulk STO is strongly compensated with $N \simeq 5 \times 10^{18}~\rm{cm^{-3}}$ background donors and acceptors. In intentionally doped bulk STO with a concentration of electrons $n_{3D} < N$ background impurities determine the electron scattering. Thus, when $n_{3D} < N$ it is natural to see in LAO/STO the same mobility as in the bulk. On the other hand, in the bulk samples with $n_{3D} > N$ the mobility collapses because scattering happens on $n_{3D}$ intentionally introduced donors. For LAO/STO the polar catastrophe which provides electrons is not supposed to provide equal number of random donors and thus the mobility should be larger. The fact that the mobility is still the same implies that for the LAO/STO the polar catastrophe model should be revisited.Comment: 4 pages and 1 figur