The 1987 Whittier Narrows, California, earthquake: A Metropolitan shock

Just 3 hours after the Whittier Narrows earthquake struck, it became clear that a heretofore unseen geological structure was seismically active beneath metropolitan Los Angeles. Contrary to initial expectations of strike-slip or oblique-slip motion on the Whittier fault, whose north end abuts the aftershock zone, the focal mechanism of the mainshock showed pure thrust faulting on a deep gently inclined surface [Hauksson et al., 1988]. This collection of nine research reports spans the spectrum of seismological, geodetic, and geological investigations carried out as a result of the Whittier Narrows earthquake. Although unseen, the structure was not unforeseen. Namson [1987] had published a retrodeformable geologic cross section (meaning that the sedimentary strata could be restored to their original depositional position) 100 km to the west of the future earthquake epicenter in which blind, or subsurface, thrust faults were interpreted to be active beneath the folded southern Transverse Ranges. Working 25 km to the west, Hauksson [1987] had also found a surprising number of microearthquakes with thrust focal mechanisms south of the Santa Monica mountains, another clue to a subsurface system of thrust faults. Finally, Davis [1987] had presented a preliminary cross section only 18 km to the west of Whittier Narrows that identified as "fault B" the thrust that would rupture later that year. Not only was the earthquake focus and its orientation compatible with the 10–15 km depth and north dipping orientation of Davis' proposed thrust, but fault B appears to continue beneath the northern flank of the Los Angeles basin, skirting within 5 km of downtown Los Angeles, an area of dense commercial high-rise building development. These results are refined and extended by Davis et al. [this issue]

Determination of Leading Twist Non-Singlet Operator Matrix Elements by QCD Sum Rules

We use QCD sum rules to determine the twist-two non-singlet operator matrix elements and fixed x structure functions paying particular regard to the estimate of the errors. Particularly for the matrix element determination, we find large uncertainties due to radiative and higher dimension contributions. We consider the origin of these large corrections and comment on their consequences for other operator matrix element determinations.Comment: 10 pages, 10 figure

Comparability of Functional MRI Response in Young and Old During Inhibition

When using fMRI to study age-related cognitive changes, it is important to establish the integrity of the hemodynamic response because, potentially, it can be affected by age and disease. However, there have been few attempts to document such integrity and no attempts using higher cognitive rather than perceptual or motor tasks. We used fMRI with 28 healthy young and older adults on an inhibitory control task. Although older and young adults differed in task performance and activation patterns, they had comparable hemodynamic responses. We conclude that activation during cognitive inhibition, which was predominantly increased in elders, was not due to vascular confounds or specific changes in hemodynamic coupling

Neural signatures of cognitive flexibility and reward sensitivity following nicotinic receptor stimulation in dependent smokers : a randomized trial

IMPORTANCE Withdrawal from nicotine is an important contributor to smoking relapse. Understanding how reward-based decision making is affected by abstinence and by pharmacotherapies such as nicotine replacement therapy and varenicline tartrate may aid cessation treatment. OBJECTIVE To independently assess the effects of nicotine dependence and stimulation of the nicotinic acetylcholine receptor on the ability to interpret valence information (reward sensitivity) and subsequently alter behavior as reward contingencies change (cognitive flexibility) in a probabilistic reversal learning task. DESIGN, SETTING, AND PARTICIPANTS Nicotine-dependent smokers and nonsmokers completed a probabilistic reversal learning task during acquisition of functional magnetic resonance imaging (fMRI) in a 2-drug, double-blind placebo-controlled crossover design conducted from January 21, 2009, to September 29, 2011. Smokers were abstinent from cigarette smoking for 12 hours for all sessions. In a fully Latin square fashion, participants in both groups underwent MRI twice while receiving varenicline and twice while receiving a placebo pill, wearing either a nicotine or a placebo patch. Imaging analysis was performed from June 15, 2015, to August 10, 2016. MAIN OUTCOME AND MEASURES A well-established computational model captured effects of smoking status and administration of nicotine and varenicline on probabilistic reversal learning choice behavior. Neural effects of smoking status, nicotine, and varenicline were tested for on MRI contrasts that captured reward sensitivity and cognitive flexibility. RESULTS The study included 24 nicotine-dependent smokers (12 women and 12 men; mean [SD] age, 35.8 [9.9] years) and 20 nonsmokers (10 women and 10 men; mean [SD] age, 30.4 [7.2] years). Computational modeling indicated that abstinent smokers were biased toward response shifting and that their decisions were less sensitive to the available evidence, suggesting increased impulsivity during withdrawal. These behavioral impairments were mitigated with nicotine and varenicline. Similarly, decreased mesocorticolimbic activity associated with cognitive flexibility in abstinent smokers was restored to the level of nonsmokers following stimulation of nicotinic acetylcholine receptors (familywise error-corrected P<.05). Conversely, neural signatures of decreased reward sensitivity in smokers (vs nonsmokers; familywise error-corrected P<.05) in the dorsal striatum and anterior cingulate cortex were not mitigated by nicotine or varenicline. CONCLUSIONS AND RELEVANCE There was a double dissociation between the effects of chronic nicotine dependence on neural representations of reward sensitivity and acute effects of stimulation of nicotinic acetylcholine receptors on behavioral and neural signatures of cognitive flexibility in smokers. These chronic and acute pharmacologic effects were observed in overlapping mesocorticolimbic regions, suggesting that available pharmacotherapies may alleviate deficits in the same circuitry for certain mental computations but not for others

12 May 2008 M = 7.9 Wenchuan, China, earthquake calculated to increase failure stress and seismicity rate on three major fault systems

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L17305, doi:10.1029/2008GL034903.The Wenchuan earthquake on the Longmen Shan fault zone devastated cities of Sichuan, claiming at least 69,000 lives. We calculate that the earthquake also brought the Xianshuihe, Kunlun and Min Jiang faults 150–400 km from the mainshock rupture in the eastern Tibetan Plateau 0.2–0.5 bars closer to Coulomb failure. Because some portions of these stressed faults have not ruptured in more than a century, the earthquake could trigger or hasten additional M > 7 earthquakes, potentially subjecting regions from Kangding to Daofu and Maqin to Rangtag to strong shaking. We use the calculated stress changes and the observed background seismicity to forecast the rate and distribution of damaging shocks. The earthquake probability in the region is estimated to be 57–71% for M ≥ 6 shocks during the next decade, and 8–12% for M ≥ 7 shocks. These are up to twice the probabilities for the decade before the Wenchuan earthquake struck.S. T. and R. S. are grateful for research fellowships at EOST- Institut de Physique du Globe de Strasbourg, France. J. L. was supported by the Charles D. Hollister Endowed Fund for Support of Innovative Research at WHOI

Multi-attributes tradespace exploration for survivability: Application to satellite radar

Multi-Attribute Tradespace Exploration (MATE) for Survivability is introduced as a general methodology for survivability analysis and demonstrated through an application to a satellite radar system. MATE for Survivability applies decision theory to the parametric modeling of thousands of design alternatives across representative distributions of disturbance environments. Survivability considerations are incorporated into the existing MATE process (i.e., a solution-generating and decision-making framework that applies decision theory to model-based design) by applying empirically-validated survivability design principles and value-based survivability metrics to concept generation and concept evaluation activities, respectively. MATE for Survivability consists of eight iterative phases: (1) define system value proposition, (2) generate concepts, (3) specify disturbances, (4) apply survivability principles, (5) model baseline system performance, (6) model impact of disturbances on dynamic system performance, (7) apply survivability metrics, and (8) select designs for further analysis. The application of MATE for Survivability to satellite radar demonstrates the importance of incorporating survivability considerations into conceptual design for identifying inherently survivable architectures that efficiently balance competing performance metrics of lifecycle cost, mission utility, and operational survivability

Genetic variation in the Catechol-O-Methyltransferase (COMT) gene and morphine requirements in cancer patients with pain

<p>Abstract</p> <p>Background</p> <p>Genetic variation contributes to differences in pain sensitivity and response to different analgesics. Catecholamines are involved in the modulation of pain and are partly metabolized by the catechol-O-methyltransferase (COMT) enzyme. Genetic variability in the <it>COMT </it>gene may therefore contribute to differences in pain sensitivity and response to analgesics. It is shown that a polymorphism in the <it>COMT </it>gene, Rs4680 (Val158Met), influence pain sensitivity in human experimental pain and the efficacy for morphine in cancer pain treatment. In this study we wanted to investigate if variability in other regions in the <it>COMT </it>gene also contributes to interindividual variability in morphine efficacy.</p> <p>Results</p> <p>We genotyped 11 single nucleotide polymorphisms (SNPs) throughout the <it>COMT </it>gene, and constructed haplotypes from these 11 SNPs, which were in Hardy-Weinberg equilibrium. We compared both genotypes and haplotypes against pharmacological, demographical and patient symptoms measurements in a Caucasian cancer patient cohort (n = 197) receiving oral morphine treatment for cancer pain. There were two frequent haplotypes (34.5% and 17.8%) in our cohort. Multivariate analyses showed that patients carrying the most frequent haplotype (34.5%) needed lower morphine doses than patients not carrying the haplotype, with a reduction factor of 0.71 (p = 0.005). On the allele level, carriers of alleles for six of the SNPs show weak associations in respect to morphine dose and the alleles associated with the lowest morphine doses constitute part of the most frequent haplotype.</p> <p>Conclusion</p> <p>This study suggests that genetic variability in the <it>COMT </it>gene influence the efficacy of morphine in cancer patients with pain, and that increased understanding of this variability is reached by expanding from analyses of single SNPs to haplotype construction and analyses.</p

A Second Pre-Wisconsinan Locality for the Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae)

Clidomys is the most distinctive but least well known member of the late Quaternary terrestrial mammal fauna of Jamaica. Here we report the second dated locality for this genus. The Illinoisan age we report further strengthens arguments we have made elsewhere, that Clidomys represents an early - probably pre-Wisconsinan - extinction that contrasts with the growing record of Holocene extinctions in the Antilles