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

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

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

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

Pseudo-acetylation of multiple sites on human Tau proteins alters Tau phosphorylation and microtubule binding, and ameliorates amyloid beta toxicity

Tau is a microtubule-associated protein that is highly soluble and natively unfolded. Its dysfunction is involved in the pathogenesis of several neurodegenerative disorders including Alzheimer's disease (AD), where it aggregates within neurons. Deciphering the physiological and pathogenic roles of human Tau (hTau) is crucial to further understand the mechanisms leading to its dysfunction in vivo. We have used a knock-out/knock-in strategy in Drosophila to generate a strain with hTau inserted into the endogenous fly tau locus and expressed under the control of the endogenous fly tau promoter, thus avoiding potential toxicity due to genetic over-expression. hTau knock-in (KI) proteins were expressed at normal, endogenous levels, bound to fly microtubules and were post-translationally modified, hence displaying physiological properties. We used this new model to investigate the effects of acetylation on hTau toxicity in vivo. The simultaneous pseudo-acetylation of hTau at lysines 163, 280, 281 and 369 drastically decreased hTau phosphorylation and significantly reduced its binding to microtubules in vivo. These molecular alterations were associated with ameliorated amyloid beta toxicity. Our results indicate acetylation of hTau on multiple sites regulates its biology and ameliorates amyloid beta toxicity in vivo

Migration and risk: net migration in marginal ecosystems and hazardous areas

The potential for altered ecosystems and extreme weather events in the context of climate change has raised questions concerning the role that migration plays in either increasing or reducing risks to society. Using modeled data on net migration over three decades from 1970 to 2000, we identify sensitive ecosystems and regions at high risk of climate hazards that have seen high levels of net in-migration and out-migration over the time period. This paper provides a literature review on migration related to ecosystems, briefly describes the methodology used to develop the estimates of net migration, then uses those data to describe the patterns of net migration for various ecosystems and high risk regions. The study finds that negative net migration generally occurs over large areas, reflecting its largely rural character, whereas areas of positive net migration are typically smaller, reflecting its largely urban character. The countries with largest population such as China and India tend to drive global results for all the ecosystems found in those countries. Results suggest that from 1970 to 2000, migrants in developing countries have tended to move out of marginal dryland and mountain ecosystems and out of drought-prone areas, and have moved towards coastal ecosystems and areas that are prone to floods and cyclones. For North America results are reversed for dryland and mountain ecosystems, which saw large net influxes of population in the period of record. Uncertainties and potential sources of error in these estimates are addressed

Myocardial ischemia with left ventricular outflow obstruction

We report an unusual case of a 32-year old man who was treated for a hypertrophic obstructive cardiomyopathy (HOCM) with a DDD pacing with short AV delay reduction in the past. Without prior notice the patient developed ventricular fibrillation and an invasive cardiac diagnostic was performed, which revealed a myocardial bridging around of the left anterior descending artery (LAD). We suspected ischemia that could be either related to LAD artery compression or perfusion abnormalities due to AV delay reduction with related to diastolic dysfunction

The effects of acute and elective cardiac surgery on the anxiety traits of patients with Marfan syndrome

BACKGROUND: Marfan syndrome is a genetic disease, presenting with dysfunction of connective tissues leading to lesions in the cardiovascular and skeletal muscle system. Within these symptoms, the most typical is weakness of the connective tissue in the aorta, manifesting as aortic dilatation (aneurysm). This could, in turn, become annuloaortic ectasia, or life-threatening dissection. As a result, life-saving and preventative cardiac surgical interventions are frequent among Marfan syndrome patients. Aortic aneurysm could turn into annuloaortic ectasia or life-threatening dissection, thus life-saving and preventive cardiac surgical interventions are frequent among patients with Marfan syndrome. We hypothesized that patients with Marfan syndrome have different level of anxiety, depression and satisfaction with life compared to that of the non-clinical patient population. METHODS: Patients diagnosed with Marfan syndrome were divided into 3 groups: those scheduled for prophylactic surgery, those needing acute surgery, and those without need for surgery (n = 9, 19, 17, respectively). To examine the psychological features of the patients, Spielberger's anxiety (STAI) test, Beck's Depression questionnaire (BDI), the Berne Questionnaire of Subjective Well-being, and the Satisfaction with Life scale were applied. RESULTS: A significant difference was found in trait anxiety between healthy individuals and patients with Marfan syndrome after acute life-saving surgery (p 0.1). Finally, a significant, medium size effect was found between patient groups on the Joy in Living scale (F (2.39) = 3.51, p = 0.040, eta2 = 0.15). CONCLUSIONS: Involving psychiatric and mental-health care, in addition to existing surgical treatment interventions, is essential for more successful recovery of patients with Marfan syndrome

Assessment of Select Climate Change Impacts on U.S. National Security

This report examines climate change impacts to U.S. national security by quantifying select impacts globally at the national level and identifying countries that are both at high risk from projected climate change and possess risk factors associated with political instability. Exposure to global sea‐level rise risk exposure is quantified by identifying low‐elevation coastal zones (LECZ), at 1, 3, 5, 7, 9, 10 and 12 meters of elevation. Countries with high risk factors for instability that also have the most people exposed to sea‐level rise include China, Philippines, India, and Indonesia. Those with the greatest percentage of population so exposed include Philippines, Egypt, and Indonesia. Within these countries, Egypt has especially high rates of population growth within the LECZ. Aggregate climate change vulnerability is quantified by using an index that takes into account both projected temperature change and adaptive capacity. For countries with high risk factors for instability, the most vulnerable countries are South Africa, Nepal, Morocco, Bangladesh, Tunisia, Paraguay, Yemen, Sudan and Côte d’Ivoire. Water scarcity is examined by comparing numbers of people living under conditions of water in the present with three future scenarios – one in which the climate remains unchanged but population changes; one in which population changes but the climate remains static; and one in which both population and climate change. Countries with high risk factors for instability that are projected to have the biggest increases in water scarcity are Mozambique, Côte d’Ivoire, Nigeria, Iraq, Guatemala, Zimbabwe, Ethiopia, Somalia, China, Syria and Algeria

Active learning and optimal climate policy

This paper develops a climate-economy model with uncertainty, irreversibility, and active learning. Whereas previous papers assume learning from one observation per period, or experiment with control variables to gain additional information, this paper considers active learning from investment in monitoring, specifically in improved observations of the global mean temperature. We find that the decision maker invests a significant amount of money in climate research, far more than the current level, in order to increase the rate of learning about climate change. This helps the decision maker make improved decisions. The level of uncertainty decreases more rapidly in the active learning model than in the passive learning model with only temperature observations. As the uncertainty about climate change is smaller, active learning reduces the optimal carbon tax. The greater the risk, the larger is the effect of learning. The method proposed here is applicable to any dynamic control problem where the quality of monitoring is a choice variable, for instance, the precision at which we observe GDP, unemployment, or the quality of education