Origin and significance of 'dispersed facies' basal ice: Svínafellsjökull, Iceland

Dispersed facies basal ice - massive (i.e. structureless) ice with dispersed debris aggregates - is present at the margins of many glaciers and, as a product of internal glacial processes, has the potential to provide important information about the mechanisms of glacier flow and the nature of the subglacial environment. The origin of dispersed facies is poorly understood, with several hypotheses having been advanced for its formation, and there is disagreement as to whether it is largely a sedimentary or a tectonic feature. We test these established hypotheses at the temperate glacier Svfnafellsjokull, Iceland, and find that none fully account for dispersed facies characteristics at this location. Instead, dispersed facies physical, sedimentological and stable-isotope (5180, 8D) characteristics favour a predominantly tectonic origin that we suggest comprises the regelation and straininduced metamorphism of debris-rich basal ice that has been entrained into an englacial position by tectonic processes operating at the base of an icefall. Further thickening of the resultant dispersed facies may also occur tectonically as a result of ice flow against the reverse bed slope of a terminal overdeepening. Lack of efficient subglacial drainage in the region of the overdeepening may limit basal melting and thus favour basal ice preservation, including the preservation of dispersed facies. Despite the relatively low sediment content of dispersed facies (~1.6% by volume), its thickness (up to 25 m) and ubiquity at Svfnafellsjokull results in a significant contribution to annual sediment discharge (1635-3270 m3 a"1) that is ~6.5 times that contributed by debris-rich stratified facies basal ice

The Supercam Instrument Suite on the NASA Mars 2020 Rover: Body Unit and Combined System Tests

The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam’s body unit (BU) and testing of the integrated instrument. The BU, mounted inside the rover body, receives light from the MU via a 5.8 m optical fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245–340 and 385–465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer containing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535–853 nm (105–7070 cm−1 Raman shift relative to the 532 nm green laser beam) with 12 cm−1 full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars. Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spectroscopy are shown, demonstrating clear mineral identification with both techniques. Luminescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these subsystems as well

Multivalent HA DNA Vaccination Protects against Highly Pathogenic H5N1 Avian Influenza Infection in Chickens and Mice

Sustained outbreaks of highly pathogenic avian influenza (HPAI) H5N1 in avian species increase the risk of reassortment and adaptation to humans. The ability to contain its spread in chickens would reduce this threat and help maintain the capacity for egg-based vaccine production. While vaccines offer the potential to control avian disease, a major concern of current vaccines is their potency and inability to protect against evolving avian influenza viruses.The ability of DNA vaccines encoding hemagglutinin (HA) proteins from different HPAI H5N1 serotypes was evaluated for its ability to elicit neutralizing antibodies and to protect against homologous and heterologous HPAI H5N1 strain challenge in mice and chickens after DNA immunization by needle and syringe or with a pressure injection device. These vaccines elicited antibodies that neutralized multiple strains of HPAI H5N1 when given in combinations containing up to 10 HAs. The response was dose-dependent, and breadth was determined by the choice of the influenza virus HA in the vaccine. Monovalent and trivalent HA vaccines were tested first in mice and conferred protection against lethal H5N1 A/Vietnam/1203/2004 challenge 68 weeks after vaccination. In chickens, protection was observed against heterologous strains of HPAI H5N1 after vaccination with a trivalent H5 serotype DNA vaccine with doses as low as 5 microg DNA given twice either by intramuscular needle injection or with a needle-free device.DNA vaccines offer a generic approach to influenza virus immunization applicable to multiple animal species. In addition, the ability to substitute plasmids encoding different strains enables rapid adaptation of the vaccine to newly evolving field isolates

Synopsis of Guidelines for the Clinical Management of Cerebral Cavernous Malformations: Consensus Recommendations based on Systematic Literature Review by the Angioma Alliance Scientific Advisory Board Clinical Experts Panel

BackgroundDespite many publications about cerebral cavernous malformations (CCMs), controversy remains regarding diagnostic and management strategies.ObjectiveTo develop guidelines for CCM management.MethodsThe Angioma Alliance ( www.angioma.org ), the patient support group in the United States advocating on behalf of patients and research in CCM, convened a multidisciplinary writing group comprising expert CCM clinicians to help summarize the existing literature related to the clinical care of CCM, focusing on 5 topics: (1) epidemiology and natural history, (2) genetic testing and counseling, (3) diagnostic criteria and radiology standards, (4) neurosurgical considerations, and (5) neurological considerations. The group reviewed literature, rated evidence, developed recommendations, and established consensus, controversies, and knowledge gaps according to a prespecified protocol.ResultsOf 1270 publications published between January 1, 1983 and September 31, 2014, we selected 98 based on methodological criteria, and identified 38 additional recent or relevant publications. Topic authors used these publications to summarize current knowledge and arrive at 23 consensus management recommendations, which we rated by class (size of effect) and level (estimate of certainty) according to the American Heart Association/American Stroke Association criteria. No recommendation was level A (because of the absence of randomized controlled trials), 11 (48%) were level B, and 12 (52%) were level C. Recommendations were class I in 8 (35%), class II in 10 (43%), and class III in 5 (22%).ConclusionCurrent evidence supports recommendations for the management of CCM, but their generally low levels and classes mandate further research to better inform clinical practice and update these recommendations. The complete recommendations document, including the criteria for selecting reference citations, a more detailed justification of the respective recommendations, and a summary of controversies and knowledge gaps, was similarly peer reviewed and is available on line www.angioma.org/CCMGuidelines

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Self-Censorship in Authoritarian States: Response bias in measures of popular support in China

The study of popular support for authoritarian regimes, and the comparative study of political attitudes, has long relied on the assumption that survey respondents provide truthful answers on surveys. However, when measuring regime support in closed political systems there is a distinct risk that individuals are less than forthright due to fear that their opinions may be made known to the public or the authorities. In order to test this assumption, we conducted a novel web-based survey in China in which we included four list experiments of commonly used items in the comparative literature on regime support. We find systematic bias for all four measures as a result of selfcensorship; substantially more individuals state that they support the regime with direct questioning than do when presented with our anonymous, indirect list experiments. The level of self-censorship, which ranges from 16 to 22 percentage points, is considerably higher than previously thought. Selfcensorship is further most prevalent among the wealthy, urban, female and younger respondents. These findings indicate that prior studies that have found high levels of support for the Chinese regime using these particular measures likely overestimate the true level of support. Further, crossnational studies which compare popular support across regime type may be systematically biased if responses are not subject to the same level of falsification across regime types.For helpful comments, we thank Oscar Almen, Nicholas Kerr, Pierre Landry, Staffan I. Lindberg, Ellen Lust, Kyle Marquardt, Sven Oskarsson, Daniela Stockmann, Katrin Uba, and Samantha A. Vortherms, and Vincent Wen for translation. We are further grateful to Gälöstiftelsen for financial support for data collection. Marcus Tannenberg also wishes to acknowledge support from the Swedish Research Council, Grant 439-2014-38, PI: Pam Fredman, Vice-Chancellor, University of Gothenburg, Swede

Don't be late for school again : Essays on education and support for democracy

An extensive body of work has found that countries with relatively educated populations are more likely to be democratically governed. Further, a large body of work argues that education is associated with a host of individual-level factors, such as political participation and democratic values, which provides a micro-level mechanism to explain the link between education and democracy. The  central claim is that education universally engenders democratic values, which in turn, drives individuals to make claim for democratic governance.  I build on this prior research in three respects. First, in Paper 1, using a sample of identical twins I show that the impact of education on political knowledge is highly confounded by family background.  Education has a positive impact on knowledge for those individuals that were not exposed to political discussion in the home during upbringing.  But for those that discussed politics with family, education has no impact on political knowledge.  Second, I challenge the claim that education has a universally positive effect by examining the role of political context.  In Papers 2 and 3 I leverage education reforms as quasi-experiments to study how the effect of education on political attitudes varies in authoritarian and democratic countries.  In Paper 2 we find that education at the primary and secondary level has no impact on support for democracy in principle, but that education in an authoritarian context leads to less satisfaction with democracy after a country transitions, whereas education in a democratic context leads to greater satisfaction with democracy.  In Paper 3 I find that higher education in an authoritarian context weakens support for authoritarian rule, but that this effect is mitigated by a strong economy. Finally, in Paper 4 we focus on the validity of survey measures of regime support in authoritarian states.  Through a series of list experiments implemented in a novel web-based survey in China we find that respondents self-censor their true level of regime support to a large degree.  Further, the level of self-censorship varies greatly by income, age, residence status, and education

Don't be late for school again : Essays on education and support for democracy

An extensive body of work has found that countries with relatively educated populations are more likely to be democratically governed. Further, a large body of work argues that education is associated with a host of individual-level factors, such as political participation and democratic values, which provides a micro-level mechanism to explain the link between education and democracy. The  central claim is that education universally engenders democratic values, which in turn, drives individuals to make claim for democratic governance.  I build on this prior research in three respects. First, in Paper 1, using a sample of identical twins I show that the impact of education on political knowledge is highly confounded by family background.  Education has a positive impact on knowledge for those individuals that were not exposed to political discussion in the home during upbringing.  But for those that discussed politics with family, education has no impact on political knowledge.  Second, I challenge the claim that education has a universally positive effect by examining the role of political context.  In Papers 2 and 3 I leverage education reforms as quasi-experiments to study how the effect of education on political attitudes varies in authoritarian and democratic countries.  In Paper 2 we find that education at the primary and secondary level has no impact on support for democracy in principle, but that education in an authoritarian context leads to less satisfaction with democracy after a country transitions, whereas education in a democratic context leads to greater satisfaction with democracy.  In Paper 3 I find that higher education in an authoritarian context weakens support for authoritarian rule, but that this effect is mitigated by a strong economy. Finally, in Paper 4 we focus on the validity of survey measures of regime support in authoritarian states.  Through a series of list experiments implemented in a novel web-based survey in China we find that respondents self-censor their true level of regime support to a large degree.  Further, the level of self-censorship varies greatly by income, age, residence status, and education

Education, Family Background, and Political Knowledge : A Test of the Compensation Hypothesis with Identical Twins

Prior research has consistently identified education as an important correlate of political knowledge, which, many argue, reflects an underlying causal relationship. However, recent work has questioned this interpretation rather arguing that family background causes one to both obtain an education and to develop political knowledge. I argue that this causal-versus-proxy debate is too simplistic. Specifically, using a sample of identical twins, I test the interaction between education, political discussion in the home, and political knowledge. I find that education is positively associated with political knowledge independent of family background and genetics for those who discussed politics with family relatively little during upbringing. However, for those who discussed politics with family members more frequently, education has no association with political knowledge independent of pre-adult factors. Therefore, education compensates for a lack of exposure to political content in the home