361 research outputs found
Merchant Shipping in a Chinese Blockade of Taiwan
There is a substantial literature on the various methods and tactics the armed forces of the Peopleās Republic of China (PRC) could employ to enforce a naval blockade of Taiwan during a Taiwan Strait crisis.1 However, there has been very little assessment of how the qualities of todayās global maritime shipping industry might affect the effectiveness of a blockade
A Comprehensive Survey of China\u27s Dynamic Shipbuilding Industry
China\u27s dynamic shipbuilding sector now has the attention of key decision makers in Washington. During testimony before the Armed Services Committee of the House of Representatives on 13 December 2007, Chief of Naval Operations (CNO) Admiral Gary Roughead observed, The fact that our shipbuilding capacity and industry is not as competitive as other builders around the world is cause for concern. Pointing directly to Beijing\u27s new prowess in this area, he concluded, [China is] very competitive on the world market. There is no question that their shipbuilding capability is increasing rapidly. The present study aims to present a truly comprehensive survey of this key sector of the growing Chinese economy. In doing so, it will provide decision makers and analysts with the clearest possible picture of the extraordinary pace of activity now under way in China\u27s ports, as well as the commercial and strategic implications flowing from this development.https://digital-commons.usnwc.edu/cmsi-red-books/1000/thumbnail.jp
Reproductive Success Across the Black-capped Chickadee (Poecile atricapillus) and Carolina Chickadee (P. carolinensis) Hybrid Zone in Ohio
Black-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (P. carolinensis) hybridize in an east-west band from New Jersey to Kansas. Within the past century, the Ohio portion of this hybrid /one and the Carolina Chickadee range to the south have been moving northward, whereas the Black-capped Chickadee range has retracted. In Ohio, we characterized the genetic composition of the hybrid zone using five diagnostic molecular loci. Although there was no evidence of assortative mating in the center of the hybrid zone, we found a relative paucity of genetically intermediate breeding females as compared with breeding males. That suggests viability selection against female hybrids, in line with Haldane\u27s rule. On the basis of reproductive variables (number of nestlings, reproductive success), we found a decrease in productivity of breeding pairs in the hybrid zone that is significantly and positively related to their probability of producing homozygous offspring at each autosomal or sex-linked locus. We also found that the decrease in productivity was significantly and positively related to the genetic composition of the male of the pair {i.e. pure male chickadees more productive). These data strongly suggest that hybrids are at a selective disadvantage. Because the zone of reduced reproductive success was considerably narrower than the zone of introgression, our results demonstrate that genetic introgression is occurring in the face of substantial selection against hybrids
Spectral asymmetry of the massless Dirac operator on a 3-torus
Consider the massless Dirac operator on a 3-torus equipped with Euclidean metric and standard spin structure. It is known that the eigenvalues can be calculated explicitly: the spectrum is symmetric about zero and zero itself is a double eigenvalue. The aim of the paper is to develop a perturbation theory for the eigenvalue with smallest modulus with respect to perturbations of the metric. Here the application of perturbation techniques is hindered by the fact that eigenvalues of the massless Dirac operator have even multiplicity, which is a consequence of this operator commuting with the antilinear operator of charge conjugation (a peculiar feature of dimension 3). We derive an asymptotic formula for the eigenvalue with smallest modulus for arbitrary perturbations of the metric and present two particular families of Riemannian metrics for which the eigenvalue with smallest modulus can be evaluated explicitly. We also establish a relation between our asymptotic formula and the eta invariant
In Vivo Airway Surface Liquid Clā Analysis with Solid-State Electrodes
The pathogenesis of cystic fibrosis (CF) airways disease remains controversial. Hypotheses that link mutations in CFTR and defects in ion transport to CF lung disease predict that alterations in airway surface liquid (ASL) isotonic volume, or ion composition, are critically important. ASL [Clā] is pivotal in discriminating between these hypotheses, but there is no consensus on this value given the difficulty in measuring [Clā] in the āthinā ASL (ā¼30 Ī¼m) in vivo. Consequently, a miniaturized solid-state electrode with a shallow depth of immersion was constructed to measure ASL [Clā] in vivo. In initial experiments, the electrode measured [Clā] in physiologic salt solutions, small volume (7.6 Ī¼l) test solutions, and in in vitro cell culture models, with ā„93% accuracy. Based on discrepancies in reported values and/or absence of data, ASL Clā measurements were made in the following airway regions and species. First, ASL [Clā] was measured in normal human nasal cavity and averaged 117.3 Ā± 11.2 mM (n = 6). Second, ASL [Clā] measured in large airway (tracheobronchial) regions were as follows: rabbit trachea and bronchus = 114.3 Ā± 1.8 mM; (n = 6) and 126.9 Ā± 1.7 mM; (n = 3), respectively; mouse trachea = 112.8 Ā± 4.2 mM (n = 13); and monkey bronchus = 112.3 Ā± 10.9 mM (n = 3). Third, Clā measurements were made in small (1ā2 mm) diameter airways of the rabbit (108.3 Ā± 7.1 mM, n = 5) and monkey (128.5 Ā± 6.8 mM, n = 3). The measured [Clā], in excess of 100 mM throughout all airway regions tested in multiple species, is consistent with the isotonic volume hypothesis to describe ASL physiology
Field evaluation of crushed glass-dredged material blends
Journal of Geotechnical and Geoenvironmental Engineering, 133(1): pp. 127-128.Based on the laboratory results reported in a companion paper, three crushed glassādredged material CGāDM blends were
prepared and evaluated in the field to explore the feasibility of using CGāDM blends in general, embankment and structural fill
applications. A trailer-mounted pugmill successfully prepared 20/ 80, 50/ 50, and 80/20 CGāDM blends dry weight percent CG content
reported first within a tolerance of Ā±5 dry % by weight of the targeted percentages. Blending criteria were routinely met at pugmill
throughputs up to 1,500 m3 / day. The constructed 20/80 CGāDM embankment was compacted to a minimum of 90% modified Proctor
compaction, whereas the 50/50 and 80/20 CGāDM embankments were constructed to a minimum of 95% modified Proctor compaction.
Twenty to 80% CG addition to DM resulted in 1.5ā5.5 kN/m3 increases in field dry densities above 100% DM, densities not achievable
with other DM stabilization techniques such as Portland cement, fly ash, and/or lime PC/FA/lime addition. CG substantially improved
the workability of DM allowing construction with conventional equipment and three person crew while achieving very consistent and
reproducible results during a timeline of frequent and heavy precipitation events. The 20/ 80, 50/ 50, and 80/20 CGāDM embankments
were characterized by average cone tip resistances on the order of 1.0, 1.5, and 2.0 MPa, respectively. An environmental evaluation of
100% CG, DM and 50/50 CGāDM blend samples coupled with an economic analysis of a scaled-up commercial application illustrated
that the CGāDM blending approach is potentially more cost effective than PC/FA/lime stabilization approaches. These features of
CGāDM blending make the process attractive for use in urban and industrial settings
Divergent viral presentation among human tumors and adjacent normal tissues
We applied a newly developed bioinformatics system called VirusScan to investigate the viral basis of 6,813 human tumors and 559 adjacent normal samples across 23 cancer types and identified 505 virus positive samples with distinctive, organ system- and cancer type-specific distributions. We found that herpes viruses (e.g., subtypes HHV4, HHV5, and HHV6) that are highly prevalent across cancers of the digestive tract showed significantly higher abundances in tumor versus adjacent normal samples, supporting their association with these cancers. We also found three HPV16-positive samples in brain lower grade glioma (LGG). Further, recurrent HBV integration at the KMT2B locus is present in three liver tumors, but absent in their matched adjacent normal samples, indicating that viral integration induced host driver genetic alterations are required on top of viral oncogene expression for initiation and progression of liver hepatocellular carcinoma. Notably, viral integrations were found in many genes, including novel recurrent HPV integrations at PTPN13 in cervical cancer. Finally, we observed a set of HHV4 and HBV variants strongly associated with ethnic groups, likely due to viral sequence evolution under environmental influences. These findings provide important new insights into viral roles of tumor initiation and progression and potential new therapeutic targets
Regaining momentum for international climate policy beyond Copenhagen
The 'Copenhagen Accord' fails to deliver the political framework for a fair, ambitious and legally-binding international climate agreement beyond 2012. The current climate policy regime dynamics are insufficient to reflect the realities of topical complexity, actor coalitions, as well as financial, legal and institutional challenges in the light of extreme time constraints to avoid 'dangerous' climate change of more than 2Ā°C. In this paper we analyze these stumbling blocks for international climate policy and discuss alternatives in order to regain momentum for future negotiations
- ā¦