Are Rapid Population Estimates Accurate? A Field Trial of Two Different Assessment Methods.

Emergencies resulting in large-scale displacement often lead to populations resettling in areas where basic health services and sanitation are unavailable. To plan relief-related activities quickly, rapid population size estimates are needed. The currently recommended Quadrat method estimates total population by extrapolating the average population size living in square blocks of known area to the total site surface. An alternative approach, the T-Square, provides a population estimate based on analysis of the spatial distribution of housing units taken throughout a site. We field tested both methods and validated the results against a census in Esturro Bairro, Beira, Mozambique. Compared to the census (population: 9,479), the T-Square yielded a better population estimate (9,523) than the Quadrat method (7,681; 95% confidence interval: 6,160-9,201), but was more difficult for field survey teams to implement. Although applicable only to similar sites, several general conclusions can be drawn for emergency planning

Earthquake source characteristics from dynamic rupture with constrained stochastic fault stress

One of the challenging tasks in predicting near-source ground motion for future earthquakes is to anticipate the spatiotemporal evolution of the rupture process. The final size of an event but also its temporal properties (propagation velocity, slip velocity) depend on the distribution of shear stress on the fault plane. Though these incipient stresses are not known for future earthquakes, they might be sufficiently well characterized in a stochastic sense. We examine the evolution of dynamic rupture in numerical models of a fault subjected to heterogeneous stress fields with varying statistical properties. By exploring the parameter space of the stochastic stress characterization for a large number of random realizations we relate generalized properties of the resulting events to the stochastic stress parameters. The nucleation zone of the simulated earthquake ruptures in general has a complex shape, but its average size is found to be independent of the stress field parameterization and is determined only by the material parameters and the friction law. Furthermore, we observe a sharp transition in event size from small to system-wide events, governed mainly by the standard deviation of the stress field. A simplified model based on fracture mechanics is able to explain this transition. Finally, we find that the macroscopic rupture parameters ( e. g., moment, moment rate, seismic energy) of our catalog of model quakes are generally consistent with observational data

Imbricated slip rate processes during slow slip transients imaged by low-frequency earthquakes

Low Frequency Earthquakes (LFEs) often occur in conjunction with transient strain episodes, or Slow Slip Events (SSEs), in subduction zones. Their focal mechanism and location consistent with shear failure on the plate interface argue for a model where LFEs are discrete dynamic ruptures in an otherwise slowly slipping interface. SSEs are mostly observed by surface geodetic instruments with limited resolution and it is likely that only the largest ones are detected. The time synchronization of LFEs and SSEs suggests that we could use the recorded LFEs to constrain the evolution of SSEs, and notably of the geodetically-undetected small ones. However, inferring slow slip rate from the temporal evolution of LFE activity is complicated by the strong temporal clustering of LFEs. Here we apply dedicated statistical tools to retrieve the temporal evolution of SSE slip rates from the time history of LFE occurrences in two subduction zones, Mexico and Cascadia, and in the deep portion of the San Andreas fault at Parkfield. We find temporal characteristics of LFEs that are similar across these three different regions. The longer term episodic slip transients present in these datasets show a slip rate decay with time after the passage of the SSE front possibly as t^(−1/4). They are composed of multiple short term transients with steeper slip rate decay as t^(−α) with α between 1.4 and 2. We also find that the maximum slip rate of SSEs has a continuous distribution. Our results indicate that creeping faults host intermittent deformation at various scales resulting from the imbricated occurrence of numerous slow slip events of various amplitudes

Mapping Coherent, Time-Varying Wavefronts from the Tohoku Tsunami into Enhanced, Time-Dependent Warning Messages

Recent results are presented to illustrate how predictions of tsunami wave impact and tsunami warning mes-sages can be improved by including information about multiple, large-amplitude wave arrivals over longer time durations and at refined spatial resolution. A deployment of ocean bottom seismometers off the coast of southern California recorded the March 2011 Tohoku tsunami on 22 differential pressure gauges. The pressure gauge tsu-nami records across the entire array show multiple large-amplitude, coherent phases arriving one hour to more than 36 hours after the initial tsunami phase. Analysis of the pressure gauge recordings reveals possible locations of the geographical sources that contributed to secondary tsunami arrivals in southern California. A beamform-ing technique is applied to the pressure gauge data to determine the azimuths and arrival times of scattered wave energy. In addition, a backward ray-tracing procedure is applied to a wide range of back azimuth starting values from the pressure gauge array to map possible scattering source locations. The results show several possible candidates of secondary tsunami source structures. These include: (1) southeastern Alaska producing a tsunami arrival 1–2 hours after the first arrival; and elongated bathymetry structures near: (2) the northern Hawaiian Is-land chain producing an arrival 1–2 hours, (3) Papua New Guinea producing an arrival 8–9 hours, and (4) French Polynesia producing an arrival 10–11 hours, all after the first arrival. These results are then incorporated into tsunami warning messages to improve clarity of the hazard threat and protective action guidance, and the specificity of impact location over time. Revised tsunami messages have been tested through online experiments with the public in order to determine how changes in message clarity and specificity affects message receiver understanding, believing, and personalizing, all of which are pre-decisional sense-making activities. The geo-physical results are mapped into modified tsunami warning messages to show how a time-varying hazard could be communicated with more effective message format and content. The results are demonstrating the effects of including clearly described locations, time of impact, and hazard impact consequences on message perception among the public

Automotive leathers – evaluating the performance limits (part II)

Content: Consumers perceive leather as a durable and natural product. To support this positive image, car manufacturers have set demanding performance profiles addressing wear, emissions and sustainable manufacture. Poor performance of auto leather becomes visible as the polymeric finishing coat wears off or cracks over time. Therefore ageing property is seen as a representative key performance parameter and is determined by checking how flexible and strong a polymer coating remains after leather has been exposed to light, heat and humidity for a given time. Ageing of leather is complex to determine and depends on various parameters and requires a full system approach . In a first step different type of crusts (wet-blue, wet-white) were prepared and finished with a standard polyurethane coating. It turned out that the selection of the right fat liquors and tanning agents as well as the presence of vegetable tannins play an important role. On top of this the effective use of proper protective chemicals like anti-oxidants is needed. In a second approach the polymer coating itself was studied and optimized with regard to aged flexing and abrasion. Parameters like polymer type, crosslinking, application technology, coating thickness and impact of additives were investigated and tested when applied on the best crust leathers selected from part 1 of this work. Results show that not only is the right selection of polymers critical but also so is the way the coat is being applied . Furthermore coating thickness greatly defines wear (abrasion), lightfastness and ageing properties. Additives like dulling agents, levelers, feel agents, waxes ,fillers although needed can weaken the integrity of the polymer matrix and consequently reduce physical and chemical fastness properties. This may also apply to a certain extent to protective additives such as anti-oxidants and UV stabilizers, but when used properly their advantages outweigh the potential disadvantages. As to application, special emphasis is given to transfer coating technology which can provide advantages in application and quality consistency but also with regards to fastness properties such as wear and ageing. Take-Away: - crust leather has a critical impact on performance of finishing coat of automotive leathers and requires careful selction of products and use of protective chemical - polymer selection and use of protective chemical play an important role for achieving good aged flexing performance - type of application of finishing coat on auto leather further determines the performance of coatin

Sonication of intramedullary nails: Clinically-related infection and contamination

Background and Aim: Sonication is currently considered the best procedure for microbiological diagnosis of implant-related osteoarticular infection, but studies in nail-related infections are lacking. The study aim was to evaluate implant sonication after intramedullary nail explantation, and relate it to microbiological cultures and clinical outcome. Patients and Methods: A study was performed in two University Hospitals from the same city. Thirty-one patients with implanted nails were prospectively included, whether with clinical infection (8 cases) or without (23 cases). Retrieved nails underwent sonication according a previously published protocol. The clinical and microbiological outcome patient was related to the presence of microorganisms in the retrieved implant. Results: Positive results appeared in 15/31 patients (9 with polymicrobial infections) almost doubling those clinically infected cases. The most commonly isolated organisms were Staphylococcus epidermidis (19.2 %) and Staphylococcus aureus (15.4 %). A significant relationship was found between the presence of positive cultures and previous local superficial infection (p=0.019). The presence of usual pathogens was significantly related to clinical infection (p=0.005) or local superficial infection (p=0.032). All patients with positive cultures showed pain diminution or absence of pain after nail removal (15/15), but this only occurred in 8 (out of 16) patients with negative cultures. Conclusions: In patients with previously diagnosed infection or local superficial infection, study of the hardware is mandatory. In cases where pain or patient discomfort is observed, nail sonication can help diagnose the implant colonization with potential pathogens that might require specific treatment to improve the final outcomePart of this work was funded by grants from the Comunidad de Madrid (S2009/MAT-1472) and from the CONSOLIDER-INGENIO Program (FUNCOAT-CSD2008- 00023). DMM was funded by a grant from the Fundación Conchita Rábago de Jiménez Día

Fatigue and functional capacity post COVID-19

Background: We explored if fatigue influenced the long-term functional capacity of patients post COVID-19. Methods: People after COVID -19, grouped by treatment setting (home - H, hospital ward - HW or intensive care unit – ICU), were studied 12 months after discharge. Fatigue-Functional Chronic Illness Assessment Questionnaire Fatigue Subscale, FACIT-F and functional capacity-6min walk test, 6MWD and 1min sit-to-stand test, 1minSTS were assessed. Groups were compared with one-way ANOVA or Kruskal-Wallis H test. Spearman’s ρ and multiple regression analyses were performed between fatigue-functional tests. Results: 148 subjects (H, n=44; HW, n=60; ICU, n=44) participated. Fatigue was clinically relevant at 12 months although not significantly different among groups [H: 41(35-49); HW: 42(33-50); ICU; 42(32-48) points; p=.979). Functional capacity was significantly higher in those treated at home (6MWD: H,626 114m, HW: 527 146m, ICU: 528 129m, p<.001; 1minSTS: H,29 11reps, HW: 23 8reps, ICU: 24 8reps, p<.002). Fatigue was significantly correlated with functional tests within each group (FACIT-F-6MWD,.317<ρ≤.550, p<.01; FACIT-F-1minSTS, .364<ρ≤.485, p<.01). Each point of FACIT-F could change 6MWD by 5-6m and 1minSTS by. 3-.5reps, explaining between 12-33% of change in 6MWD and 17-22% of change in 1minSTS (Table 1). Conclusions: Fatigue seems to influence functional capacity of patients post COVID-19. Early management of this symptom seems important for their long-term management.publishe

Mapping Coherent, Time-Varying Wavefronts from the Tohoku Tsunami into Enhanced, Time-Dependent Warning Messages

Recent results are presented to illustrate how predictions of tsunami wave impact and tsunami warning mes-sages can be improved by including information about multiple, large-amplitude wave arrivals over longer time durations and at refined spatial resolution. A deployment of ocean bottom seismometers off the coast of southern California recorded the March 2011 Tohoku tsunami on 22 differential pressure gauges. The pressure gauge tsu-nami records across the entire array show multiple large-amplitude, coherent phases arriving one hour to more than 36 hours after the initial tsunami phase. Analysis of the pressure gauge recordings reveals possible locations of the geographical sources that contributed to secondary tsunami arrivals in southern California. A beamform-ing technique is applied to the pressure gauge data to determine the azimuths and arrival times of scattered wave energy. In addition, a backward ray-tracing procedure is applied to a wide range of back azimuth starting values from the pressure gauge array to map possible scattering source locations. The results show several possible candidates of secondary tsunami source structures. These include: (1) southeastern Alaska producing a tsunami arrival 1–2 hours after the first arrival; and elongated bathymetry structures near: (2) the northern Hawaiian Is-land chain producing an arrival 1–2 hours, (3) Papua New Guinea producing an arrival 8–9 hours, and (4) French Polynesia producing an arrival 10–11 hours, all after the first arrival. These results are then incorporated into tsunami warning messages to improve clarity of the hazard threat and protective action guidance, and the specificity of impact location over time. Revised tsunami messages have been tested through online experiments with the public in order to determine how changes in message clarity and specificity affects message receiver understanding, believing, and personalizing, all of which are pre-decisional sense-making activities. The geo-physical results are mapped into modified tsunami warning messages to show how a time-varying hazard could be communicated with more effective message format and content. The results are demonstrating the effects of including clearly described locations, time of impact, and hazard impact consequences on message perception among the public