The Effects of the Quasi-Biannual Oscillation on Tephra Distribution from a Plinian Eruption

2021 ◽  
Author(s):  
Steffen Eisele ◽  
Yang Qingyuan ◽  
Caroline Bouvet de Maissoneuve ◽  
Susanna F. Jenkins
Keyword(s):  
Tropical Regions ◽  
Plinian Eruptions ◽  
West Sumatra ◽  
Stratospheric Wind ◽  
Downward Propagation ◽  
Hazard Assessments ◽  
African Rift ◽  
Two Phases ◽  
Wind Regimes

<p>The quasi-biannual oscillation (QBO) dominates the equatorial zonal wind in the tropical stratosphere. Alternating easterly and westerly wind regimes form in the upper stratosphere and propagate downwards to the tropopause with a mean period of approximately 28 months. The westerly phase of the QBO is characterized by faster and more regular downward propagation, while the easterly phase has higher intensity (up to double the wind speed) and longer duration. Long-term lower stratospheric wind records indicate prevailing easterly winds (~60 % of the time) for the tropical regions. However, during westerly phases of the QBO, the wind is exclusively blowing towards the east. This leads to different but well predictable tephra distributions during the two phases. The QBO is effectively controlling the variations of the lower stratospheric wind regimes between 15º N and 15º S. Therefore, the effects of the QBO on spatial tephra distribution impact all tropical volcanic regions, including Central America, SE-Asia, the Andean Northern Volcanic Zone and the African Rift. We use the Tephra2 model in a case study from Tandikat volcano in West Sumatra to analyse the different QBO phases' effects on tephra distribution from Plinian eruptions. Incorporating the QBO in probabilistic hazard assessments for Plinian eruptions improves the accuracy of the hazard assessments. Understanding the effects of the QBO on the spatial tephra distribution will also help re-evaluate distal tephra records.   </p>

scholarly journals When Housing and Communities Were Delivered: A Case Study of Post-Wenchuan Earthquake Rural Reconstruction and Recovery

2021 ◽  
Vol 13 (14) ◽  
pp. 7629
Author(s):  
Haorui Wu
Keyword(s):  
Built Environment ◽  
Wenchuan Earthquake ◽  
Place Making ◽  
Sustainable Rural Development ◽  
Residential Communities ◽  
Social Settings ◽  
Disaster Survivors ◽  
Two Phases

This study contributes to an in-depth examination of how Wenchuan earthquake disaster survivors utilize intensive built environment reconstruction outcomes (housing and infrastructural systems) to facilitate their long-term social and economic recovery and sustainable rural development. Post-disaster recovery administered via top-down disaster management systems usually consists of two phases: a short-term, government-led reconstruction (STGLR) of the built environment and a long-term, survivor-led recovery (LTSLR) of human and social settings. However, current studies have been inadequate in examining how rural disaster survivors have adapted to their new government-provided housing or how communities conducted their long-term recovery efforts. This qualitative case study invited sixty rural disaster survivors to examine their place-making activities utilizing government-delivered, urban-style residential communities to support their long-term recovery. This study discovered that rural residents’ recovery activities successfully perpetuated their original rural lives and rebuilt social connections and networks both individually and collectively. However, they were only able to manage their agriculture-based livelihood recovery temporarily. This research suggests that engaging rural inhabitants’ place-making expertise and providing opportunities to improve their housing and communities would advance the long-term grassroots recovery of lives and livelihoods, achieving sustainable development.

Leishmaniasis and its relevance to UK Armed Forces

2014 ◽  
Vol 100 (3) ◽  
pp. 238-243
Author(s):  
HC Preedy ◽  
MS Bailey
Keyword(s):  
Armed Forces ◽  
Medical Personnel ◽  
Patient Characteristics ◽  
Military Operations ◽  
Tropical Regions ◽  
Evidence Based Treatment ◽  
Phlebotomine Sandflies ◽  
Clinical Syndromes ◽  
The Relationship

AbstractLeishmaniasis is an infectious disease caused by Leishmania protozoa, transmitted by the bite of phlebotomine sandflies. It causes a spectrum of clinical syndromes, of which the most common are cutaneous and visceral leishmaniasis. Clinical presentation is highly variable and is dependent on multiple factors, such as Leishmania species and patient characteristics (including immune competence). The relationship between these variables is poorly understood, and there is no single, evidence-based treatment for the disease. Currently management focuses on identification of the species, but this requires specialist tests which are often unavailable, particularly on military operations. Leishmaniasis is of particular relevance to military medical personnel as it is endemic in many tropical and sub-tropical regions of the world, including Belize, Iraq and Afghanistan where UK Armed Forces may be deployed. It can present a potentially serious threat to military personnel deployed in endemic areas due to the possibility of long-term sequelae of infection.

scholarly journals Voices We Forget—Danish Students Experience of Returning to School Following Parental Bereavement

2016 ◽  
Vol 78 (1) ◽  
pp. 24-42 ◽  
Author(s):  
Martin Lytje
Keyword(s):  
Focus Group ◽  
Data Collection ◽  
Return To School ◽  
Parental Bereavement ◽  
Focus Group Interviews ◽  
Academic Challenges ◽  
Two Phases ◽  
Group Interviews ◽  
Returning To School

This study explores how Danish students experience returning to school following parental bereavement. Eighteen focus group interviews with 39 participants aged 9 to 17 years were conducted. All participants had experienced the loss of a primary caregiver. Data collection was divided into two phases. In Phase I, 22 participants from four grief groups were interviewed 4 times over the course of a year. During Phase II, confirmatory focus groups were undertaken with the 17 participants. This article explores findings related to the four themes of initial school response, long-term support, challenges within the class, and academic challenges. The study found that (a) students struggle to reconnect with classmates following the return to school and often feel alone, (b) schools fail to have guidelines in place for what they are allowed to do if becoming sad the class, and (c) schools seem to forget their loss as time passes.

scholarly journals Hematopoietic recovery after transplantation is primarily derived from the stochastic contribution of hematopoietic stem cells

2021 ◽  
Author(s):  
Stefan Radtke ◽  
Mark Enstrom ◽  
Dnyanada P. Pande ◽  
Margaret L. Cui ◽  
Ravishankar Madhu ◽  
...  
Keyword(s):  
Clonal Diversity ◽  
Enhanced Sampling ◽  
Primate Model ◽  
Hematopoietic Stem ◽  
Neutrophil Recovery ◽  
Hematopoietic Recovery ◽  
Hematopoietic Reconstitution ◽  
Initial Recovery ◽  
Two Phases

Reconstitution after hematopoietic stem cell (HSC) transplantation is assumed to occur in two distinct phases: initial recovery mediated by short-term progenitors and long-term repopulation by multipotent HSCs which do not contribute to hematopoietic reconstitution during the first 6-9 months. We have previously reported the transplantation and exclusive engraftment of the HSC-enriched CD34+CD45RA-CD90+ phenotype in a nonhuman primate model. Here, we closely followed the clonal diversity and kinetics in these animals. Enhanced sampling and high density clonal tracking within the first 3 month revealed that multipotent HSCs actively contributed to the early phases of neutrophil recovery and became the dominant source for blood cells as early as 50 days after transplant. Longitudinal changes in clonal diversity supported a stochastic engraftment of HSCs with the majority of HSCs clones vanishing early during neutrophil recovery and a smaller fraction of HSC clones expanding into bigger pools to support long-term hematopoiesis. In contrast to the bi-phasic model, we propose that hematopoietic recovery after myeloablation and transplantation is primarily derived from HSCs in a stochastic manner rather than in two phases by independent cell populations.

scholarly journals Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with the intraseasonal oscillation in the Southwest Amazon

2005 ◽  
Vol 35 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Rachel Ifanger Albrecht ◽  
Maria Assunção Faus da Silva Dias
Keyword(s):  
Intraseasonal Oscillation ◽  
Convective Precipitation ◽  
Wind Regime ◽  
Tropical Regions ◽  
Stratiform Precipitation ◽  
Type Size ◽  
Global Atmospheric Circulation ◽  
Microphysical Processes ◽  
Wind Regimes ◽  
Precipitation Formation

The distinction between convective and stratiform precipitation profiles around various precipitating systems existent in tropical regions is very important to the global atmospheric circulation, which is extremely sensitive to vertical latent heat distribution. In South America, the convective activity responds to the Intraseasonal Oscillation (IOS). This paper analyzes a disdrometer and a radar profiler data, installed in the Ji-Paraná airport, RO, Brazil, for the field experiment WETAMC/LBA & TRMM/LBA, during January and February of 1999. The microphysical analysis of wind regimes associated with IOS showed a large difference in type, size and microphysical processes of hydrometeor growth in each wind regime: easterly regimes had more turbulence and consequently convective precipitation formation, and westerly regimes had a more stratiform precipitation formation.

Characterization of Atrazine Accumulation by Excised Velvetleaf (Abutilon theophrasti) Roots

Weed Science ◽  
1983 ◽  
Vol 31 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Thomas P. Price ◽  
Nelson E. Balke
Keyword(s):  
Initial Phase ◽  
External Solution ◽  
Abutilon Theophrasti ◽  
Linear Phase ◽  
Rapid Absorption ◽  
Two Temperatures ◽  
Two Phases ◽  
Excised Tissue

Long-term absorption of14C-atrazine [2-chloro-4 - (ethylamino) - 6 - (isopropylamino) -s- triazine] by excised velvetleaf (Abutilon theophrastiMedic.) roots was investigated. A rapid, initial phase of absorption was followed by a long-term, linear phase of absorption, which resulted in atrazine accumulation in the tissue to concentrations above the external solution. This accumulation did not result from metabolism of the atrazine. Aging of the excised tissue appeared to be responsible for the accumulation. Dinitrophenol, but not cyanide, inhibited accumulation. Atrazine accumulation decreased as the temperature during absorption was decreased. The Q10the absorption rate was ca. 2.5 between 15 and 25 C. Efflux of atrazine from the tissue occurred in two phases. At 25 C, loss of 80% of the atrazine occurred in 20 min. At 4C, the rate of this efflux was slower and the phase lasted longer. At both 4 and 25 C a second, slower phase of efflux occurred through at least 6 h and resulted in loss of equal amounts of atrazine at the two temperatures. These experiments show that, in addition to rapid absorption of atrazine to a passive equilibrium, excised velvetleaf roots accumulate atrazine by a metabolically dependent process over long periods of time.

scholarly journals Habitats and Diversity of Subterranean Macroscopic Freshwater Invertebrates: Main Gaps and Future Trends

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2170
Author(s):  
Elzbieta Dumnicka ◽  
Tanja Pipan ◽  
David Culver
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Habitat Size ◽  
Tropical Regions ◽  
High Productivity ◽  
Local Diversity ◽  
Geographic Patterns ◽  
Temperature Oscillations ◽  
Subterranean Species

Caves are the best studied aquatic subterranean habitat, but there is a wide variety of these habitats, ranging in depth below the surface and size of the spaces (pore or habitat size). Both factors are important in setting limits to species composition and richness. In addition to caves, among the most important shallow aquatic subterranean habitats are the hyporheal (underflow of rivers and streams), the hypotelminorheal (very superficial drainages with water exiting in seeps), epikarst, and calcrete aquifers. Although it is little studied, both body size and species composition in the different habitats is different. Because of high levels of endemism and difficulty in access, no subterranean habitats are well sampled, even caves. However, there are enough data for robust generalizations about some geographic patterns. Individual hotspot caves are concentrated in the Dinaric region of southern Europe, and overall, tropical regions have fewer obligate aquatic cave dwellers (stygobionts). In all subterranean aquatic habitats, regional diversity is much higher than local diversity, but local diversity (especially single cave diversity) may be a useful predictor of regional species richness. In Europe there is a ridge of high aquatic subterranean species richness basically extending east from the French–Spanish border. Its cause may be either high productivity or that long-term temperature oscillations are at a minimum. With increased collecting and analysis, global and continental trends should become clearer.

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