Localized precipitation and runoff on Mars

We use the Mars Regional Atmospheric Modeling System (MRAMS) to simulate lake storms on Mars, finding that intense localized precipitation will occur for lake size >=10^3 km^2. Mars has a low-density atmosphere, so deep convection can be triggered by small amounts of latent heat release. In our reference simulation, the buoyant plume lifts vapor above condensation level, forming a 20km-high optically-thick cloud. Ice grains grow to 200 microns radius and fall near (or in) the lake at mean rates up to 1.5 mm/hr water equivalent (maximum rates up to 6 mm/hr water equivalent). Because atmospheric temperatures outside the surface layer are always well below 273K, supersaturation and condensation begin at low altitudes above lakes on Mars. In contrast to Earth lake-effect storms, lake storms on Mars involve continuous precipitation, and their vertical velocities and plume heights exceed those of tropical thunderstorms on Earth. Convection does not reach above the planetary boundary layer for lakes O(10^2) mbar. Instead, vapor is advected downwind with little cloud formation. Precipitation occurs as snow, and the daytime radiative forcing at the land surface due to plume vapor and storm clouds is too small to melt snow directly (<+10 W/m^2). However, if orbital conditions are favorable, then the snow may be seasonally unstable to melting and produce runoff to form channels. We calculate the probability of melting by running thermal models over all possible orbital conditions and weighting their outcomes by probabilities given by Laskar et al., 2004. We determine that for an equatorial vapor source, sunlight 15% fainter than at present, and snowpack with albedo 0.28 (0.35), melting may occur with 4%(0.1%) probability. This rises to 56%(12%) if the ancient greenhouse effect was modestly (6K) greater than today.Comment: Submitted to JGR Planet

Too Big to Fail — U.S. Banks’ Regulatory Alchemy: Converting an Obscure Agency Footnote into an “At Will” Nullification of Dodd-Frank’s Regulation of the Multi-Trillion Dollar Financial Swaps Market

The multi-trillion-dollar market for, what was at that time wholly unregulated, over-the-counter derivatives (“swaps”) is widely viewed as a principal cause of the 2008 worldwide financial meltdown. The Dodd-Frank Act, signed into law on July 21, 2010, was expressly considered by Congress to be a remedy for this troublesome deregulatory problem. The legislation required the swaps market to comply with a host of business conduct and anti-competitive protections, including that the swaps market be fully transparent to U.S. financial regulators, collateralized, and capitalized. The statute also expressly provides that it would cover foreign subsidiaries of big U.S. financial institutions if their swaps trading could adversely impact the U.S. economy or represent the use of extraterritorial trades as an attempt to “evade” Dodd-Frank. In July 2013, the CFTC promulgated an 80-page, triple-columned, and single-spaced “guidance” implementing Dodd-Frank’s extraterritorial reach, i.e., that manner in which Dodd-Frank would apply to swaps transactions executed outside the United States. The key point of that guidance was that swaps trading within the “guaranteed” foreign subsidiaries of U.S. bank holding company swaps dealers were subject to all of Dodd-Frank’s swaps regulations wherever in the world those subsidiaries’ swaps were executed. At that time, the standardized industry swaps agreement contemplated that, inter alia, U.S. bank holding company swaps dealers’ foreign subsidiaries would be “guaranteed” by their corporate parent, as was true since 1992. In August 2013, without notifying the CFTC, the principal U.S. bank holding company swaps dealer trade association privately circulated to its members standard contractual language that would, for the first time, “deguarantee” their foreign subsidiaries. By relying only on the obscure footnote 563 of the CFTC guidance’s 662 footnotes, the trade association assured its swaps dealer members that the newly deguaranteed foreign subsidiaries could (if they so chose) no longer be subject to Dodd-Frank. As a result, it has been reported (and it also has been understood by many experts within the swaps industry) that a substantial portion of the U.S. swaps market has shifted from the large U.S. bank holding companies swaps dealers and their U.S. affiliates to their newly deguaranteed “foreign” subsidiaries, with the attendant claim by these huge big U.S. bank swaps dealers that Dodd-Frank swaps regulation would not apply to these transactions. The CFTC also soon discovered that these huge U.S. bank holding company swaps dealers were “arranging, negotiating, and executing” (“ANE”) these swaps in the United States with U.S. bank personnel and, only after execution in the U.S., were these swaps formally “assigned” to the U.S. banks’ newly “deguaranteed” foreign subsidiaries with the accompanying claim that these swaps, even though executed in the U.S., were not covered by Dodd-Frank. In October 2016, the CFTC proposed a rule that would have closed the “deguarantee” and “ANE” loopholes completely. However, because it usually takes at least a year to finalize a “proposed” rule, this proposed rule closing the loopholes in question was not finalized prior to the inauguration of President Trump. All indications are that it will never be finalized during a Trump Administration. Thus, in the shadow of the recent tenth anniversary of the Lehman failure, there is an understanding among many market regulators and swaps trading experts that large portions of the swaps market have moved from U.S. bank holding company swaps dealers and their U.S. affiliates to their newly deguaranteed foreign affiliates where Dodd- Frank swaps regulation is not being followed. However, what has not moved abroad is the very real obligation of the lender of last resort to rescue these U.S. swaps dealer bank holding companies if they fail because of poorly regulated swaps in their deguaranteed foreign subsidiaries, i.e., the U.S. taxpayer. While relief is unlikely to be forthcoming from the Trump Administration or the Republican-controlled Senate, some other means will have to be found to avert another multi-trillion-dollar bank bailout and/or a financial calamity caused by poorly regulated swaps on the books of big U.S. banks. This paper notes that the relevant statutory framework affords state attorneys general and state financial regulators the right to bring so-called “parens patriae” actions in federal district court to enforce, inter alia, Dodd- Frank on behalf of a state’s citizens. That kind of litigation to enforce the statute’s extraterritorial provisions is now badly needed

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Blocked and Free Access Real-Time Splitting Protocols

Addressing the challenge of packet transmission in a wireless soft real-time system, we present five splitting protocols that take packet deadlines into account. With them, connectionless service with realtime QoS guarantees at the MAC layer can be offered. Three protocols are blocked access and two are free access algorithms. Mathematical models are developed and results compared with simulations. As is the case with non real-time splitting algorithms, the blocked access versions offer higher success rates than the free access versions. We further show that of the two best performing blocked access protocols, under moderate to heavy loads, the Sliding Partition CRA outperforms the Two Cell CRA. 1 Introduction A group of nodes working in concert to complete some set of tasks by specified deadlines is a real-time system. Such systems can be broadly subcategorized into hard and soft real-time systems. Hard real-time systems are those whose data is so important that all deadlines must be..

Analysis of a Soft Real-Time Random Access Protocol

A communications network that is part of a soft real-time system may need to transmit messages within a bounded delay, but may allow some messages to miss this bound and be dropped within a maximum pre-specified rate of message loss. In this paper, we describe a media access protocol for soft real-time systems implemented on a slotted radio channel with binary feedback. The protocol is based on the Gallager FCFS window-splitting algorithm, but incorporates strict delay bounds using packet laxities. We present an analytic model for this protocol by examining the probable lengths of the collision resolution intervals given the current lag at any time. Both analytic and simulation results are obtained to study the maximum input traffic rates that can be sustained for various laxities, delay bounds, and message loss rates. Keywords. Random access algorithms, Real-time communication protocols, Time constrained communications, Multiple-access protocols. 1 Introduction Applications directly..

Evaluation of Wireless Soft Real-Time Protocols

Communication between current military real-time systems and future interconnection of general purpose, embedded real-time systems will often require wireless communications. However, there has been little work undertaken to offer support for real-time applications on wireless networks. We present and evaluate three protocols; variations of two published protocols by Paterakis and Gallager as well as our new one, the Sliding Partition (SP) collision resolution algorithm (CRA). In a real-time setting, the modified Gallager CRA consistently performs worst of the three we consider. We observe that when the deadline range is small, the Sliding Partition CRA performs best. When the deadline range is large, however, the Paterakis CRA performs slightly better than the SP CRA. Both analytic and simulation results are obtained to study the maximum input traffic rates that can be sustained for various laxities, delay bounds, and message loss rates. 1

Blocked and Free Access Real-Time Splitting Protocols

Addressing the problem of timely packet transmission in a wireless soft real-time system such as one would find on the battlefield, we present five splitting protocols that take packet deadlines into account. Three are blocked access and two are free access algorithms. Mathematical models of the algorithms are developed, and compared with simulations. We show, as expected, that the blocked access algorithms usually offer higher success rates than the free access versions. Of the two best performing blocked access protocols, performance differences are slight on a lightly loaded channel. Under heavy load, however, one is shown to have better performance, and thus would be the best choice for implementation

Real-Time Wireless Communication using Splitting Protocols

Addressing the problem of packet transmission in a wireless soft real-time system, we present five splitting protocols that take packet deadlines into account. We show, as in the case of non real-time splitting algorithms, that blocked access versions offer higher success rates than free access ones. Of the two best performing blocked access protocols, performance under moderate to heavy loads further shows the superiority of the Sliding Partition CRA over the Two Cell CRA. I. Introduction A group of nodes working in concert to complete some set of tasks by specified deadlines is a real-time system. Such systems can be broadly subcategorized into hard and soft real-time systems. Hard real-time systems are those whose data is so important that all deadlines must be met to avoid catastrophic physical or financial failures. Examples might include aeronautic systems, power plants, or weapons fire control systems. Soft real-time systems, however, can safely afford some amount of lateness..

Blocked and Free Access Real-Time Splitting Protocols

Addressing the challenge of packet transmission in a wireless soft real-time system, we present five splitting protocols that take packet deadlines into account. With them, connectionless service with real-time QoS guarantees at the MAC layer can be offered. Three protocols are blocked access and two are free access algorithms. Mathematical models are developed and results compared with simulations. As is the case with non real-time splitting algorithms, the blocked access versions offer higher success rates than the free access versions. We further show that of the two best performing blocked access protocols, under moderate to heavy loads, the Sliding Partition CRA outperforms the Two Cell CRA

Wireless Mac Protocols For Real-Time Battlefield Communications

Addressing the problem of timely packet transmission in a wireless soft real-time system such as one would find on the battlefield, we present five splitting protocols that take packet deadlines into account. Three are blocked access and two are free access algorithms. Mathematical models of the algorithms are developed, and compared with simulations. We show, as expected, that the blocked access algorithms usually offer higher success rates than the free access versions. Of the two best performing blocked access protocols, performance differences are slight on a lightly loaded channel. Under heavy load, however, one is shown to have better performance, and thus would be the best choice for implementation