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A simple, portable capillary refill time (CRT) simulator is not commercially available. This device would be useful in mass-casualty simulations with multiple volunteers or mannequins depicting a variety of clinical findings and CRTs. The objective of this study was to develop and evaluate a prototype CRT simulator in a disaster simulation context.
A CRT prototype simulator was developed by embedding a pressure-sensitive piezo crystal, and a single red light-emitting diode (LED) light was embedded, within a flesh-toned resin. The LED light was programmed to turn white proportionate to the pressure applied, and gradually to return to red on release. The time to color return was adjustable with an external dial. The prototype was tested for feasibility among two cohorts: emergency medicine physicians in a tabletop exercise and second year medical students within an actual disaster triage drill. The realism of the simulator was compared to video-based CRT, and participants used a Visual Analog Scale (VAS) ranging from “completely artificial” to “as if on a real patient.” The VAS evaluated both the visual realism and the functional (eg, tactile) realism. Accuracy of CRT was evaluated only by the physician cohort. Data were analyzed using parametric and non-parametric statistics, and mean Cohen’s Kappas were used to describe inter-rater reliability.
The CRT simulator was generally well received by the participants. The simulator was perceived to have slightly higher functional realism (P=.06, P=.01) but lower visual realism (P=.002, P=.11) than the video-based CRT. Emergency medicine physicians had higher accuracy on portrayed CRT on the simulator than the videos (92.6% versus 71.1%; P<.001). Inter-rater reliability was higher for the simulator (0.78 versus 0.27; P<.001).
A simple, LED-based CRT simulator was well received in both settings. Prior to widespread use for disaster triage training, validation on participants’ ability to accurately triage disaster victims using CRT simulators and video-based CRT simulations should be performed.
ChangTP, SantillanesG, Claudius I, PhamPK, KovedJ, CheyneJ, Gausche-HillM, KajiAH, SrinivasanS, DonofrioJJ, BirC. Use of a Novel, Portable, LED-Based Capillary Refill Time Simulator within a Disaster Triage Context. Prehosp Disaster Med. 2017;32(4):451–456.
We present a tool for analysis and fit of stellar spectra using a mega database of 15,000 atmosphere models for OB stars. We have developed software tools, which allow us to find the model that best fits to an observed spectrum, comparing equivalent widths and line ratios in the observed spectrum with all models of the database. We use the Hα, Hβ, Hγ, and Hδ lines as criterion of stellar gravity and ratios of He II λ4541/He I λ4471, He II λ4200/(He I+He II λ4026), He II λ4541/He I λ4387, and He II λ4200/He I λ4144 as criterion of Teff.
Using the pediatric version of the Simple Triage and Rapid Treatment (JumpSTART) algorithm for the triage of pediatric patients in a mass-casualty incident (MCI) requires assessing the results of each step and determining whether to move to the next appropriate action. Inappropriate application can lead to performance of unnecessary actions or failure to perform necessary actions.
To report overall accuracy and time required for triage, and to assess if the performance of unnecessary steps, or failure to perform required steps, in the triage algorithm was associated with inaccuracy of triage designation or increased time to reach a triage decision.
Medical students participated in an MCI drill in which they triaged both live actors portraying patients and computer-based simulated patients to the four triage levels: minor, delayed, immediate, and expectant. Their performance was timed and compared to intended triage designations and a priori determined critical actions.
Thirty-three students completed 363 scenarios. The overall accuracy was 85.7% and overall mean time to assign a triage designation was 70.4 seconds, with decreasing times as triage acuity level decreased. In over one-half of cases, the student omitted at least one action and/or performed at least one action that was not required. Each unnecessary action increased time to triage by a mean of 8.4 seconds and each omitted action increased time to triage by a mean of 5.5 seconds.
Increasing triage level, performance of inappropriate actions, and omission of recommended actions were all associated with increasing time to perform triage.
ClaudiusI, KajiAH, SantillanesG, CiceroMX, DonofrioJJ, Gausche-HillM, SrinivasanS, ChangTP. Accuracy, Efficiency, and Inappropriate Actions Using JumpSTART Triage in MCI Simulations. Prehosp Disaster Med. 2015;30(5):457–460.
Multiple modalities for simulating mass-casualty scenarios exist; however, the ideal modality for education and drilling of mass-casualty incident (MCI) triage is not established.
Medical student triage accuracy and time to triage for computer-based simulated victims and live moulaged actors using the pediatric version of the Simple Triage and Rapid Treatment (JumpSTART) mass-casualty triage tool were compared, anticipating that student performance and experience would be equivalent.
The victim scenarios were created from actual trauma records from pediatric high-mechanism trauma presenting to a participating Level 1 trauma center. The student-reported fidelity of the two modalities was also measured. Comparisons were done using nonparametric statistics and regression analysis using generalized estimating equations.
Thirty-three students triaged four live patients and seven computerized patients representing a spectrum of minor, immediate, delayed, and expectant victims. Of the live simulated patients, 92.4% were given accurate triage designations versus 81.8% for the computerized scenarios (P=.005). The median time to triage of live actors was 57 seconds (IQR=45-66) versus 80 seconds (IQR=58-106) for the computerized patients (P<.0001). The moulaged actors were felt to offer a more realistic encounter by 88% of the participants, with a higher associated stress level.
While potentially easier and more convenient to accomplish, computerized scenarios offered less fidelity than live moulaged actors for the purposes of MCI drilling. Medical students triaged live actors more accurately and more quickly than victims shown in a computerized simulation.
ClaudiusI, KajiA, SantillanesG, CiceroM, DonofrioJJ, Gausche-HillM, SrinivasanS, ChangTP.
Comparison of Computerized Patients versus Live Moulaged Actors for a Mass-casualty Drill. Prehosp Disaster Med.2015; 30(5): 438–442.
Oligonychus punicae and Oligonychus perseae (Acari: Tetranychidae) are the most important mite species affecting avocado orchards in Mexico. Here we used nucleotide sequence data from segments of the nuclear ribosomal internal transcribed spacers (ITS1 and ITS2) and mitochondrial cytochrome oxidase subunit I (COI) genes to assess the phylogenetic relationships between both sympatric mite species and, using only ITS sequence data, examine genetic variation and population structure in both species, to test the hypothesis that, although both species co-occur, their genetic population structures are different in both Michoacan state (main producer) and Mexico state. Phylogenetic analysis showed a clear separation between both species using ITS and COI sequence information. Haplotype network analysis done on 24 samples of O. punicae revealed low genetic diversity with only three haplotypes found but a significant geographical population structure confirmed by analysis of molecular variance (AMOVA) and Kimura-2-parameter (K2P) analyses. In addition, a Mantel test revealed that geographical isolation was a factor responsible for the genetic differentiation. In contrast, analyses of 22 samples of O. perseae revealed high genetic diversity with 15 haplotypes found but no geographical structure confirmed by the AMOVA, K2P and Mantel test analyses. We have suggested that geographical separation is one of the most important factors driving genetic variation, but that it affected each species differently. The role of the ecology of these species on our results, and the importance of our findings in the development of monitoring and control strategies are discussed.
Long duration Gamma Ray Bursts (LGRB) are thought to originate from massive rotating
stars and the interaction of their expanding jet will be affected by the structure of
their circumburst medium. In this work we use rotating stellar models of massive stars to
determine the state of circumbust material in various types of progenitor scenarios and we
describe how this external matter can appear in GRB observations.
There exist many physical processes that may contribute to the driving of turbulence in galactic disks. Some of them could drive turbulence even in the absence of star formation. For example, hydrodynamic (HD) or magnetohydrodynamic (MHD) instabilities, frequent mergers of small satellite clumps, ram pressure, or infalling gas clouds. In this work we present numerical simulations to study the interaction of compact high velocity clouds (CHVC) with the outskirts of magnetized gaseous disks. With our numerical simulations we show that the rain of small HVCs onto the disk is a potential source of random motions in the outer parts of Hi disks.
There is evidence for the ecological extinction of the native prey of the puma Puma concolor in north-western Argentine Patagonia. In this study we examine whether this is also the case in southern Patagonia. From 2004 to 2007 we examined the puma’s diet in three protected areas and two sheep ranches in Santa Cruz province. A total of 282 puma scats were analysed. In two of the protected areas and in the ranches 60–74% of the puma’s diet was native prey. Prey species were primarily guanaco Lama guanicoe, followed by Patagonian mara Dolichotis patagonum, lesser rhea Pterocnemia pennata pennata, Patagonian pichi Zaedyus pichiy and Magellanic penguin Spheniscus magellanicus. In the third protected area the main prey was the European hare Lepus europaeus. Our results show a clear difference in the diet of the puma in southern compared to north-western Patagonia. Large native herbivores (i.e. guanaco and lesser rhea) maintain their role as the main prey species for the puma in southern Patagonia. We suggest, therefore, that native prey could be restored to those areas of Argentine Patagonia, such as the north-west, where they are currently ecologically extinct. Facilitating native species recovery and/or restoration and applying more rigorous controls to prevent the introduction of potential alien prey species of the puma both, within and outside protected areas, needs to be evaluated as a regional strategy.
Unveiling the mechanisms through which the somitogenesis regulatory network exerts
spatiotemporal control of the somitic patterning has required a combination of
experimental and mathematical modeling strategies. Significant progress has been made for
the zebrafish clockwork. However, due to its complexity, the clockwork of the amniote
segmentation regulatory network has not been fully elucidated. Here, we address the
question of how oscillations are arrested in the amniote segmentation clock. We do this by
constructing a minimal model of the regulatory network, which privileges architectural
information over molecular details. With a suitable choice of parameters, our model is
able to reproduce the oscillatory behavior of the Wnt, Notch and FGF signaling pathways in
presomitic mesoderm (PSM) cells. By introducing positional information via a single Wnt3a
gradient, we show that oscillations are arrested following an infinite-period bifurcation.
Notably: the oscillations increase their amplitude as cells approach the anterior PSM and
remain in an upregulated state when arrested; the transition from the oscillatory regime
to the upregulated state exhibits hysteresis; and opposing Fgf8 and RA gradients along the
PSM naturally arise in our simulations. We hypothesize that the interaction between a
limit cycle (originated by the Notch delayed-negative feedback loop) and a bistable switch
(originated by the Wnt-Notch positive cross-regulation) is responsible for the observed
segmentation patterning. Our results agree with previously unexplained experimental
observations and suggest a simple plausible mechanism for spatiotemporal control of
somitogenesis in amniotes.
Massive main sequence stars are fast rotators. Stellar rotation affects massive stellar rotation due to rotationally induced mixing processes, the increase of mass loss rates, etc. and also affects the circumstellar medium due to their interaction with the stellar wind. The parameters of stellar winds depends on stellar parameters so the wind parameters change as the star evolves, coupling the evolution of circumstellar medium to the star itself. In this work we used a stellar code to build models of two massive stars (30 and 40 M⊙) and we used their wind parameters to simulate the hydrodynamics of their surrounding gas with the ZEUS-3D code in order to explore the effects of stellar rotation in the pre-supernova environments.
Coronal mass ejections (CMEs) are solar eruptions into interplanetary space of as much as a few billion tons of plasma, with embedded magnetic fields from the Sun's corona. These perturbations play a very important role in solar–terrestrial relations, in particular in the spaceweather. In this work we present some preliminary results of the software development at the Universidad Nacional Autónoma de México to performe Remote MHD Numerical Simulations. This is done to study the evolution of the CMEs in the interplanetary medium through a Web–based interface and the results are store into a database. The new astrophysical computational tool is called the Mexican Virtual Solar Observatory (MVSO) and is aimed to create theoretical models that may be helpful in the interpretation of observational solar data.
We know that the galactic magnetic field possesses a random component in addition to the mean uniform component, with comparable strength of the two components. This random component is considered to play important roles in the evolution of the interstellar medium (ISM). In this work we present numerical simulations associated with the interaction of the supersonic flows located at high latitude in our Galaxy (High Velocity Clouds, HVC) with the magnetized galactic ISM in order to study the effect that produces a random magnetic field in the evolution of this objects.
Hill functions follow from the equilibrium state of the reaction in which n ligands simultaneously
bind a single receptor. This result if often employed to interpret the Hill coefficient as
the number of ligand binding sites in all kinds of reaction schemes. Here, we study the equilibrium
states of the reactions in which n ligand bind a receptor sequentially, both non-cooperatively and
in a cooperative fashion. The main outcomes of such analysis are that: n is not a good estimate,
but only an upper bound, for the Hill coefficient; while the Hill coefficient depends quite strongly
on the cooperativity level among ligands. We finally use these results to discuss the feasibility
and constrains of using Hill functions to model the regulatory functions in mathematical models of
gene regulatory networks.
The Virtual Solar Observatory (VSO) concept outlines a software environment for searching, obtaining and analyzing data from archives of solar data that are distributed at many different observatories around the world (Hill 2006, in this volume). The VSO, however, not only provides fast and reliable access to the existing data of Solar Active Regions, but also represents a powerful and unique tool to perform numerical simulations of the evolution and present state of solar phenomena. Two centers at UNAM, the Institute of Astronomy (IA) and the Supercomputer Center (DGSCA), along with the Sonora University, are working together to create the Mexican Virtual Solar Observatory (MVSO) that will be part of a wider national effort.
The immunological, haematological and enzymatic responses to the inoculation in pigs of 100,000 embryonated eggs of Toxocara canis were studied. Fifteen females were inoculated and three remained as controls. Haematological values were analysed from day 7 p.i. until day 126 p.i. In the inoculated group, white blood cells were raised on day 14 p.i. and eosinophil values on days 7, 14, 21, 35 and 49 p.i. showing significant differences compared with controls (P<0.05). Absolute eosinophil counts (per ml) presented two rises, the first on days 7, 14 and 21 p.i. and the second on days 35 and 49 p.i. Blood biochemistry was maintained within normal values. Serological examination by ELISA to determine antibody levels against Toxocara canis L2/L3 excretory–secretory (ES) antigens showed values higher than the positive cut-off (1:32) from day 7 p.i. and until the end of the study on day 126 p.i., presenting two peaks: one on day 28 p.i. and the second covering days 49 to 56 p.i. Western blots of sera of inoculated animals presented, from day 7 p.i., two polypeptide bands of 55 and 70 kDa MW and, from day 56 p.i., an additional band of 120 kDa MW, all of which persisted until the end of the study. Immunological responses were sustained over time. No direct correlation was observed between the rise in eosinophils and antibody titres. To validate the conclusions, more studies are required on the polypeptide bands.