157 research outputs found
What do LLMs need to Synthesize Correct Router Configurations?
We investigate whether Large Language Models (e.g., GPT-4) can synthesize
correct router configurations with reduced manual effort. We find GPT-4 works
very badly by itself, producing promising draft configurations but with
egregious errors in topology, syntax, and semantics. Our strategy, that we call
Verified Prompt Programming, is to combine GPT-4 with verifiers, and use
localized feedback from the verifier to automatically correct errors.
Verification requires a specification and actionable localized feedback to be
effective. We show results for two use cases: translating from Cisco to Juniper
configurations on a single router, and implementing no-transit policy on
multiple routers. While human input is still required, if we define the
leverage as the number of automated prompts to the number of human prompts, our
experiments show a leverage of 10X for Juniper translation, and 6X for
implementing no-transit policy, ending with verified configurations
LIGHTYEAR: Using Modularity to Scale BGP Control Plane Verification
Current network control plane verification tools cannot scale to large
networks, because of the complexity of jointly reasoning about the behaviors of
all nodes in the network. In this paper we present a modular approach to
control plane verification, whereby end-to-end network properties are verified
via a set of purely local checks on individual nodes and edges. The approach
targets the verification of safety properties for BGP configurations and
provides guarantees in the face of both arbitrary external route announcements
from neighbors and arbitrary node/link failures. We have proven the approach
correct and also implemented it in a tool called Lightyear. Experimental
results show that Lightyear scales dramatically better than prior control plane
verifiers. Further, we have used Lightyear to verify three properties of the
wide area network of a major cloud provider, containing hundreds of routers and
tens of thousands of edges. To our knowledge no prior tool has been
demonstrated to provide such guarantees at that scale. Finally, in addition to
the scaling benefits, our modular approach to verification makes it easy to
localize the causes of configuration errors and to support incremental
re-verification as configurations are updatedComment: 12 pages (+ 2 pages references), 3 figures submitted to NSDI '2
Comparison of hypertension healthcare outcomes among older people in the USA and England
Funding: Economic and Social Research Council. G1001375/1. Medical Research Council. G1001375/1. US Department of Health and Human Services. National Institutes of Health. National Institute on Aging. 2R01 AG030153.Background The US and England have very different health systems. Comparing hypertension care outcomes in each country enables an evaluation of the effectiveness of each system. Method The English Longitudinal Study of Ageing and the Health and Retirement Survey are used to compare the prevalence of controlled, uncontrolled and undiagnosed hypertension in the population aged over 50 in the US and in England. Results Controlled hypertension is more prevalent in the US (age 50 to 64: 0.53 (0.50-0.57) and age 65+: 0.51 (0.49-0.53)) than in England (age 50 to 64: 0.45 (0.42-0.48) and age 65+: 0.42 (0.40-0.45)). This difference is driven by lower undiagnosed hypertension in the US (age 50 to 64: 0.18 (0.15-0.21) and age 65+: 0.13 (0.12-0.14)) relative to England (age 50 to 64: 0.26 (0.24-0.29) and age 65+: 0.22 (0.20-0.24)). The prevalence of uncontrolled hypertension is very similar in the US (age 50 to 64: 0.29 (0.26-0.32) and age 65+: 0.36 (0.34-0.38)) and England (age 50 to 64: 0.29 (0.26-0.32) and age 65+: 0.36 (0.34-0.39)). Hypertension care outcomes are comparable across US insurance categories. In both countries undiagnosed hypertension is positively correlated with wealth (ages 50-64). Uncontrolled hypertension declines with rising wealth in the US. Conclusions Different diagnostic practices are likely to drive the cross-country differences in undiagnosed hypertension. US government health systems perform at least as well as private health care and are more equitable in the distribution of care outcomes. Higher undiagnosed hypertension among the affluent may reflect less frequent medical contact.Publisher PDFPeer reviewe
A Critical Examination of the X-Wind Model for Chondrule and Calcium-rich, Aluminum-rich Inclusion Formation and Radionuclide Production
Meteoritic data, especially regarding chondrules and calcium-rich,
aluminum-rich inclusions (CAIs), and isotopic evidence for short-lived
radionuclides (SLRs) in the solar nebula, potentially can constrain how
planetary systems form. Intepretation of these data demands an astrophysical
model, and the "X-wind" model of Shu et al. (1996) and collaborators has been
advanced to explain the origin of chondrules, CAIs and SLRs. It posits that
chondrules and CAIs were thermally processed < 0.1 AU from the protostar, then
flung by a magnetocentrifugal outflow to the 2-3 AU region to be incorporated
into chondrites. Here we critically examine key assumptions and predictions of
the X-wind model. We find a number of internal inconsistencies: theory and
observation show no solid material exists at 0.1 AU; particles at 0.1 AU cannot
escape being accreted into the star; particles at 0.1 AU will collide at speeds
high enough to destroy them; thermal sputtering will prevent growth of
particles; and launching of particles in magnetocentrifugal outflows is not
modeled, and may not be possible. We also identify a number of incorrect
predictions of the X-wind model: the oxygen fugacity where CAIs form is orders
of magnitude too oxidizing; chondrule cooling rates are orders of magnitude
lower than those experienced by barred olivine chondrules; chondrule-matrix
complementarity is not predicted; and the SLRs are not produced in their
observed proportions. We conclude that the X-wind model is not relevant to
chondrule and CAI formation and SLR production. We discuss more plausible
models for chondrule and CAI formation and SLR production.Comment: Accepted for publication in The Astrophysical Journa
High cocoa polyphenol rich chocolate may reduce the burden of the symptoms in chronic fatigue syndrome
<p>Abstract</p> <p>Background</p> <p>Chocolate is rich in flavonoids that have been shown to be of benefit in disparate conditions including cardiovascular disease and cancer. The effect of polyphenol rich chocolate in subjects with chronic fatigue syndrome (CFS) has not been studied previously.</p> <p>Methods</p> <p>We conducted a double blinded, randomised, clinical pilot crossover study comparing high cocoa liquor/polyphenol rich chocolate (HCL/PR) in comparison to simulated iso-calorific chocolate (cocoa liquor free/low polyphenols(CLF/LP)) on fatigue and residual function in subjects with chronic fatigue syndrome. Subjects with CFS having severe fatigue of at least 10 out of 11 on the Chalder Fatigue Scale were enrolled. Subjects had either 8 weeks of intervention in the form of HCL/PR or CLF/LP, with a 2 week wash out period followed by 8 weeks of intervention with the other chocolate.</p> <p>Results</p> <p>Ten subjects were enrolled in the study. The Chalder Fatigue Scale score improved significantly after 8 weeks of the HCL/PR chocolate arm [median (range) Exact Sig. (2-tailed)] [33 (25 - 38) vs. 21.5 (6 - 35) 0.01], but that deteriorated significantly when subjects were given simulated iso-calorific chocolate (CLF/CP) [ 28.5 (17 - 20) vs. 34.5 (13-26) 0.03]. The residual function, as assessed by the London Handicap scale, also improved significantly after the HCL/PR arm [0.49 (0.33 - 0.62) vs. 0.64 (0.44 - 0.83) 0.01] and deteriorated after iso-calorific chocolate [00.44 (0.43 - 0.68) vs. 0.36 (0.33 - 0.62)0.03]. Likewise the Hospital Anxiety and Depression score also improved after the HCL/PR arm, but deteriorated after CLF/CP. Mean weight remained unchanged throughout the trial.</p> <p>Conclusion</p> <p>This study suggests that HCL/PR chocolate may improve symptoms in subjects with chronic fatigue syndrome.</p
Tele-branding in TVIII: the network as brand and the programme as brand
In the era of TVIII, characterized by deregulation, multimedia conglomeration, expansion and increased competition, branding has emerged as a central industrial practice. Focusing on the case of HBO, a particularly successful brand in TVIII, this article argues that branding can be understood not simply as a feature of television networks, but also as a characteristic of television programmes. It begins by examining how the network as brand is constructed and conveyed to the consumer through the use of logos, slogans and programmes. The role of programmes in the construction of brand identity is then complicated by examining the sale of programmes abroad, where programmes can be seen to contribute to the brand identity of more than one network. The article then goes on to examine programme merchandising, an increasingly central strategy in TVIII. Through an analysis of different merchandising strategies the article argues that programmes have come to act as brands in their own right, and demonstrates that the academic study of branding not only reveals the development of new industrial practices, but also offers a way of understanding the television programme and its consumption by viewers in a period when the texts of television are increasingly extended across a range of media platforms
Self-productivity and complementarities in human development : evidence from MARS
This paper investigates the role of self-productivity and home resources in capability formation from infancy to adolescence. In addition, we study the complementarities between basic cognitive, motor and noncognitive abilities and social as well as academic achievement. Our data are taken from the Mannheim Study of Children at Risk (MARS), an epidemiological cohort study following the long-term outcome of early risk factors. Results indicate that initial risk conditions cumulate and that differences in basic abilities increase during development. Self-productivity rises in the developmental process and complementarities are evident. Noncognitive abilities promote cognitive abilities and social achievement. There is remarkable stability in the distribution of the economic and socio-emotional home resources during the early life cycle. This is presumably a major reason for the evolution of inequality in human development
Environmental risk assessments for transgenic crops producing output trait enzymes
The environmental risks from cultivating crops producing output trait enzymes can be rigorously assessed by testing conservative risk hypotheses of no harm to endpoints such as the abundance of wildlife, crop yield and the rate of degradation of crop residues in soil. These hypotheses can be tested with data from many sources, including evaluations of the agronomic performance and nutritional quality of the crop made during product development, and information from the scientific literature on the mode-of-action, taxonomic distribution and environmental fate of the enzyme. Few, if any, specific ecotoxicology or environmental fate studies are needed. The effective use of existing data means that regulatory decision-making, to which an environmental risk assessment provides essential information, is not unnecessarily complicated by evaluation of large amounts of new data that provide negligible improvement in the characterization of risk, and that may delay environmental benefits offered by transgenic crops containing output trait enzymes
Polymorphisms near TBX5 and GDF7 are associated with increased risk for Barrett's esophagus.
BACKGROUND & AIMS: Barrett's esophagus (BE) increases the risk of esophageal adenocarcinoma (EAC). We found the risk to be BE has been associated with single nucleotide polymorphisms (SNPs) on chromosome 6p21 (within the HLA region) and on 16q23, where the closest protein-coding gene is FOXF1. Subsequently, the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) identified risk loci for BE and esophageal adenocarcinoma near CRTC1 and BARX1, and within 100 kb of FOXP1. We aimed to identify further SNPs that increased BE risk and to validate previously reported associations. METHODS: We performed a genome-wide association study (GWAS) to identify variants associated with BE and further analyzed promising variants identified by BEACON by genotyping 10,158 patients with BE and 21,062 controls. RESULTS: We identified 2 SNPs not previously associated with BE: rs3072 (2p24.1; odds ratio [OR] = 1.14; 95% CI: 1.09-1.18; P = 1.8 × 10(-11)) and rs2701108 (12q24.21; OR = 0.90; 95% CI: 0.86-0.93; P = 7.5 × 10(-9)). The closest protein-coding genes were respectively GDF7 (rs3072), which encodes a ligand in the bone morphogenetic protein pathway, and TBX5 (rs2701108), which encodes a transcription factor that regulates esophageal and cardiac development. Our data also supported in BE cases 3 risk SNPs identified by BEACON (rs2687201, rs11789015, and rs10423674). Meta-analysis of all data identified another SNP associated with BE and esophageal adenocarcinoma: rs3784262, within ALDH1A2 (OR = 0.90; 95% CI: 0.87-0.93; P = 3.72 × 10(-9)). CONCLUSIONS: We identified 2 loci associated with risk of BE and provided data to support a further locus. The genes we found to be associated with risk for BE encode transcription factors involved in thoracic, diaphragmatic, and esophageal development or proteins involved in the inflammatory response
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