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Decades of urban growth and development on the Asian megadeltas
The current and ongoing expansion of urban areas worldwide represents the largest mass migration in human history. It is well known that the world's coastal zones are associated with large and growing concentrations of population, urban development and economic activity. Among coastal environments, deltas have long been recognized for both benefits and hazards. This is particularly true on the Asian megadeltas, where the majority of the world's deltaic populations reside. Current trends in urban migration, combined with demographic momentum suggest that the already large populations on the Asian megadeltas will continue to grow. In this study, we combine recently released gridded population density (circa 2010) with a newly developed night light change product (1992 to 2012) and a digital elevation model to quantify the spatial distribution of population and development on the nine Asian megadeltas. Bivariate distributions of population as functions of elevation and coastal proximity quantify potential exposure of deltaic populations to flood and coastal hazards. Comparison of these distributions for the Asian megadeltas show very different patterns of habitation with peak population elevations ranging from 2 to 11 m above sea level over a wide range of coastal proximities. Over all nine megadeltas, over 174 million people reside below a peak population elevation of 7 m. Changes in the spatial extent of anthropogenic night light from 1992 to 2012 show widely varying extents and changes of lighted urban development. All of the deltas except the Indus show the greatest increases in night light brightness occurring at elevations < 10 m. At global and continental scales, growth of settlements of all sizes takes the form of evolving spatial networks of development. Spatial networks of lighted urban development in Asia show power law scaling properties consistent with other continents, but much higher rates of growth. The three largest networks of development in China all occur on deltas and adjacent lowlands, and are growing faster than the rest of the urban network in China. Since 2000, the Huanghe Delta + North China Plain urban network has surpassed the Japanese urban network in size and may soon connect with the Changjiang Delta + Yangtze River urban network to form the largest conurbation in Asia
"To Feel the Drumming Earth Come Upward": Indigenizing the American Studies Discipline, Field, Movement
"Indigeneity at the Crossroads of American Studies." Published as a special joint issue with American Studies, Volume 46, No. 3/4, Fall 2005
Long Term Outcome of Childhood Bicuspid Aortic Valve
The most common congenital heart defect is a bicuspid aortic valve (BAV), which is often genetic and the cause is unknown. The defect occurs in only 1% of the general population. A BAV is not able to fully stop blood from leaking back into the heart, which is known as aortic regurgitation. Another common issue with a BAV is that it may be too stiff to fully open, which is known as aortic stenosis. In early childhood, children with aortic stenosis often need palliation with a balloon or surgical valvotomy. As these children develop, they may need subsequent, more definitive procedures such as a Ross procedure, insertion of a tissue valve or mechanical valve, or a valve repair. These definitive operations are used to address recurrent aortic stenosis or regurgitation. As a result, comparing the long-term complications of valve interventions in infancy was an area of considerable interest. The goal of this study was to compare whether one procedure is more effective in providing a more functional status in adulthood since comparative data on the morbidity and mortality associated with each definitive repair in a contemporaneous cohort is lacking. Clinical evidence suggests that repeat surgical procedures are very common in all surgical interventions for bicuspid aortic valve with aortic stenosis in childhood. Incidences of a greater number of aortic valve surgery is associated with a higher incidence of surgical complications and endocarditis. Long-term follow up on the odds of a composite adverse outcome are less with a Ross procedure.https://digitalcommons.unmc.edu/surp2021/1011/thumbnail.jp
Measurement of the shear strength of a charge-density wave
We have explored the shear plasticity of charge density waves (CDWs) in
niobium triselenide samples with cross-sections having a single
micro-fabricated thickness step. Shear stresses along the step result from
thickness-dependent CDW pinning. For small thickness differences the CDW depins
elastically at the volume average depinning field. For large thickness
differences the thicker, more weakly pinned side depins first via plastic
shear. A simple model describes the qualitative features of our data, and
yields a value for the CDW's shear strength of approximately 9.5*10^3 N/m^2 and
a lower bound for the elastic shear modulus of 2.1*10^4 N/m^2. These values are
orders of magnitude smaller than the CDW's longitudinal modulus but are much
larger than corresponding values for flux-line lattices, and may explain the
relative coherence of the CDW response.Comment: 10 pages, 4 figures, submitted to Physical Review Letter
NbSe3: Effect of Uniaxial Stress on the Threshold Field and Fermiology
We have measured the effect of uniaxial stress on the threshold field ET for
the motion of the upper CDW in NbSe3. ET exhibits a critical behavior, ET ~ (1
- e/ec)^g, wher e is the strain, and ec is about 2.6% and g ~ 1.2. This
ecpression remains valid over more than two decades of ET, up to the highest
fields of about 1.5keV/m. Neither g nor ec is very sensitive to the impurity
concentraction. The CDW transition temperature Tp decreases linearly with e at
a rate dTp/de = -10K/%, and it does not show any anomaly near ec. Shubnikov
de-Haas measurements show that the extremal area of the Fermi surface decreases
with increasing strain. The results suggest that there is an intimate
relationship between pinning of the upper CDW and the Fermiology of NbSe3.Comment: 4 pages, 5 figure
Revalidation of Pyxicephalus angusticeps Parry, 1982 (Anura : Natatanura : Pyxicephalidae), a bullfrog endemic to the lowlands of eastern Africa
Pyxicephalus currently contains three recognized species, viz. P. adspersus, P. edulis and P. obbianus, the former two of which
have a long history of confusion. Parry (1982) described P. adspersus angusticeps from Beira, Mozambique, which was
synonymized with P. edulis. We re-examine the taxonomic status of Pyxicephalus taxa from Mozambique, examining the types
and contrasting them to congeners throughout Africa. Morphological characters previously used to delimit species in
Pyxicephalus are examined, and problems with some identified. Additional diagnostic characters and their variation in
Pyxicephalus are discussed, and a revised key is provided. Confusion among species in the genus, type localities, literature and
folklore led to P. adspersus angusticeps being incorrectly synonymized with P. edulis. We formally revalidate P. angusticeps,
and designate a lectotype for P. edulis. The identity of voucher specimens from previous work suggests that the breeding
ecology of P. angusticeps is distinct from that of P. adspersus and P. edulis, and that the advertisement call of P. angusticeps
was used as part of the evidence for elevating P. edulis out of synonymy with P. adspersus. The previous confusion of P.
adspersus and P. edulis does not affect the recognition of P. angusticeps. The wider implication of the previous
misidentification of P. angusticeps as P. edulis is that most of the museum material labeled as P. adspersus from East Africa is
P. edulis, and most of the museum material labeled as P. edulis from East Africa is P. angusticeps. This conclusion has been
confirmed from East African museum material thus far examined.This research was facilitated by NSF-DEB grants 1021247 to E. Scott-Prendini and C.J. Raxworthy and 1021299 to K.M. Kjer.http://www.mapress.com/zootaxa/hb2016Zoology and Entomolog
Crossover from 2-dimensional to 1-dimensional collective pinning in NbSe3
We have fabricated NbSe structures with widths comparable to the
Fukuyama-Lee-Rice phase-coherence length. For samples already in the
2-dimensional pinning limit, we observe a crossover from 2-dimensional to
1-dimensional collective pinning when the crystal width is less than 1.6
m, corresponding to the phase-coherence length in this direction. Our
results show that surface pinning is negligible in our samples, and provide a
means to probe the dynamics of single domains giving access to a new regime in
charge-density wave physics.Comment: 4 pages, 2 figures, and 1 table. Accepted for publication in Physical
Review
Contributions of spontaneous phase slippage to linear and non-linear conduction near the Peierls transition in thin samples of o-TaS_3
In the Peierls state very thin samples of TaS_3 (cross-section area \sim
10^{-3} mkm^2) are found to demonstrate smearing of the I-V curves near the
threshold field. With approaching the Peierls transition temperature, T_P, the
smearing evolves into smooth growth of conductance from zero voltage
interpreted by us as the contribution of fluctuations to the non--linear
conductance. We identify independently the fluctuation contribution to the
linear conductance near T_P. Both linear and non-linear contributions depend on
temperature with close activation energies \sim (2 - 4) x 10^3 K and apparently
reveal the same process. We reject creep of the {\it continuous} charge-density
waves (CDWs) as the origin of this effect and show that it is spontaneous phase
slippage that results in creep of the CDW. A model is proposed accounting for
both the linear and non-linear parts of the fluctuation conduction up to T_P.Comment: 6 pages, 5 Postscript figure, RevTeX, accepted for publication in PR
Herpesvirus reactivation and socioeconomic position: a community-based study
Elevated antibodies to latent herpesviruses have been demonstrated to be a reliable marker of diminished cellular immunity and recently have been associated with low socioeconomic position (SEP) in older adults. Extending these observations in a community-based study over a wide age range would provide an important new direction for investigating mechanisms underlying poor health outcomes in individuals with low SEP
Medium-Term Complications Associated With Coronary Artery Aneurysms After Kawasaki Disease: A Study From the International Kawasaki Disease Registry.
Background Coronary artery aneurysms (CAAs) may occur after Kawasaki disease (KD) and lead to important morbidity and mortality. As CAA in patients with KD are rare and heterogeneous lesions, prognostication and risk stratification are difficult. We sought to derive the cumulative risk and associated factors for cardiovascular complications in patients with CAAs after KD. Methods and Results A 34-institution international registry of 1651 patients with KD who had CAAs (maximum CA
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