490 research outputs found
Public Response to a Catastrophic Southern California Earthquake: A Sociological Perspective
This paper describes a hypothetical scenario of public response to a large regional earthquake on the southern section of the San Andreas Fault. Conclusive social and behavioral science research over decades has established that the behavior of individuals in disaster is, on the whole, controlled, rational, and adaptive, despite popular misperceptions that people who experience a disaster are dependent upon and problematic for organized response agencies. We applied this knowledge to portray the response of people impacted by the earthquake focusing on actions they will take during and immediately following the cessation of the shaking including: immediate response, search and rescue, gaining situational awareness through information seeking, making decisions about evacuation and interacting with organized responders. Our most general conclusion is that the actions of ordinary people in this earthquake scenario comprised the bulk of the initial response effort, particularly in those areas isolated for lengthy periods of time following the earthquake
Pseudoresonance mechanism of all-optical frequency standard operation
We propose a novel approach to all-optical frequency standard design, based
on a counterintuitive combination of the coherent population trapping effect
and signal discrimination at the maximum of absorption for the probe radiation.
The short-term stability of such a standard can achieve the level of
10^-14/(\tau)^1/2. The physics beyond this approach is dark resonance splitting
caused by interaction of the nuclear magnetic moment with the external magnetic
field.Comment: revtex4, references adde
AC Stark-shift in CPT-based Cs miniature atomic clocks
We report on studies on the light-shift in caesium miniature atomic clocks based on coherent population trapping (CPT) using a micro-fabricated buffer-gas cell (MEMS cell). The CPT signal is observed on the Cs D1-line by coupling the two hyperfine ground-state Zeeman sublevels involved in the clock transition to a common excited state, using two coherent electromagnetic fields. These light fields are created with a distributed feedback laser and an electro-optical modulator. We study the light-shift phenomena at different cell temperatures and laser wavelengths around 894.6nm. By adjusting the cell temperature, conditions are identified where a miniature CPT atomic clock can be operated with simultaneously low temperature coefficient and suppressed light-shift. The impact of the light-shift on the clock frequency stability is evaluated. These results are relevant for improving the long-term frequency stability of CPT-based Cs vapour-cell clock
Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants.
Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut
Obstacles and disaster risk reduction: Survey of Memphis organizations
Accepted VersionThe disaster management literature is replete with surveys at the community and household levels. However, few exist at the organizational level. This study attempts to fill this void by examining the effect of organizational obstacles on disaster risk reduction. The data come from a survey of 227 organizations in Memphis, Tennessee. This study investigates three obstacles to disaster risk reduction: lack of organizational support, lack of information, and lack of financial resources. The findings show that organizations are more likely to engage in low-effort activities indirectly related to risk reduction and are less likely to engage in high-effort activities directly related to risk reduction. The most important obstacle is lack of information about the frequency of disasters, magnitude of disasters, or organizational benefits of reducing disaster risks. Lack of financial resources and lack of organizational support are sometimes positively associated with risk-reducing activities, suggesting that, when organizations engage in risk-reducing activities, some obstacles become more apparent. The study concludes with implications, limitations, and future research strategies.National Science Foundatio
Social Participation and Disaster Risk Reduction Behaviors in Tsunami Prone Areas
This paper examines the relationships between social participation and disaster risk reduction actions. A survey of 557 households in tsunami prone areas in Phang Nga, Thailand was conducted following the 2012 Indian Ocean earthquakes. We use a multivariate probit model to jointly estimate the likelihood of undertaking three responses to earthquake and tsunami hazards (namely, (1) following disaster-related news closely, (2) preparing emergency kits and/or having a family emergency plan, and (3) having an intention to migrate) and community participation.We find that those who experienced losses from the 2004 tsunami are more likely to participate in community activities and respond to earthquake hazards. Compared to men, women are more likely to prepare emergency kits and/or have an emergency plan and have a greater intention to migrate. Living in a community with a higher proportion of women with tertiary education increases the probability of engaging in community activities and carrying out disaster risk reduction measures. Individuals who participate in village-based activities are 5.2% more likely to undertake all three risk reduction actions compared to those not engaging in community activities. This implies that encouraging participation in community activities can have positive externalities in disaster mitigation
Distinctive physiological muscle synergy patterns define the Box and Block Task execution as revealed by electromyographic features
Stroke survivors experience muscular pattern alterations of the upper limb that decrease their ability to perform daily-living activities. The Box and Block test (BBT) is widely used to assess the unilateral manual dexterity. Although BBT provides insights into functional performance, it returns limited information about the mechanisms contributing to the impaired movement. This study aims at exploring the BBT by means of muscle synergies analysis during the execution of BBT in a sample of 12 healthy participants with their dominant and non-dominant upper limb. Results revealed that: (i) the BBT can be described by 1 or 2 synergies; the number of synergies (ii) does not differ between dominant and non-dominant sides and (iii) varies considering each phase of the task; (iv) the transfer phase requires more synergies. Clinical Relevance— This preliminary study characterizes muscular synergies during the BBT task in order to establish normative patterns that could assist in understanding the neuromuscular demands and support future evaluations of stroke deficit
Frequency-stabilised laser reference system for water vapour spectroscopy and sensing applications
To acheive the requirements of DIAL instrument, a frequency detection unit (FDU) was realised for water vapour spectroscopy. For this we have developed and realised an ECDL, which can be adjusted at 935 nm or at 942 nm, a region also considered as possible for the WALES (water vapour lidar experiment in space) transmitter. The second main subsystem of the FDU, a frequency reference unit (FRU), grants short- and long-term frequency stabilities of the ISL. Offset-locking with frequency differences up to 19 GHz has been experimentally demonstrated with the proposed techniqu
Diode laser frequency stabilisation for water-vapour differential absorption sensing
We describe a low-power continuous-wave laser system for water-vapour sensing applications in the 935-nm region. The system is based on extended-cavity diode lasers and distributed-feedback lasers and delivers four single-mode frequency-stabilised optical signals. Three lasers are locked to three water-vapour absorption lines of different strengths, whereas the fourth lies outside any absorption line. On-line stabilisation is performed by wavelength-modulation spectroscopy using compact water-vapour reference cells. An offset-locking technique implemented around an electrical filter is applied for the stabilisation of the off-line slave laser to an on-line master laser at a frequency detuning of 18.8 GHz. Stabilities in the order of 15 MHz over one day were observed for the strongest lines, at the detection limit of the measurement instrumentation. The developed techniques and schemes can be applied to other wavelength ranges and molecular species. Differential absorption lidar instrumentation can in particular benefit from such a system when the stabilised lasers serve as injection seeders to pulsed power oscillators. © Springer-Verlag 2006
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