Wilder Weather: Laura Ingalls Wilder and Her Famous Tornado

Laura Ingalls Wilder’s Story On a hot, humid, and gusty summer day shortly before their wedding (in August 1885), Laura Ingalls and Almanzo Wilder take a buggy ride south of De Smet. Laura and Almanzo “sense” storminess in the air and watch towering clouds develop. They turn back toward home. Laura and Almanzo watch a thunderstorm to their west produce funnel clouds and then a tornado. While the storm moves from the northwest, they drive the horses toward the northeast and away from the path. Laura and Almanzo return to Laura’s house. Almanzo and Pa (Charles) Ingalls set out to assist anyone struck by the tornado. Returning later that night, Almanzo and Pa report that a homestead was struck. Two boys on mules were hit, and one of the boys died. The homestead was destroyed, but the front door was lofted high and fell to the ground, intact, at the home site shortly after the tornado had passed

Measurement of Nitrous Acid Production from Aerosol Surfaces using Photo-fragmentation Laser Induced Fluorescence

The hydroxyl radical (OH) is the primary oxidant in the atmosphere with its concentration determining the lifetime of many species and its reaction with volatile organic compounds leading to the production of secondary organic aerosols and tropospheric ozone. It is therefore important that its sources are well understood. Nitrous acid (HONO) is an important source of OH, building up overnight and is photolysed to form OH in the morning. HONO is also present during the day at much lower concentrations. Models however are currently under predicting these daytime concentrations, indicating a missing source of HONO. With HONO being a dominant source of OH in polluted environments it is important that its concentration is accurately modelled in order to predict a correct OH production rate. In order to identify and study these missing sources and determine their atmospheric relevance, a photo-fragmentation laser induced fluorescence (PF-LIF) instrument has been built and coupled to an aerosol flow tube to provide a fast and sensitive measurement of HONO. Two aerosol types, previously proposed as possible HONO sources, have been investigated. Illuminated TiO2, was found to generate HONO in the presence of NO2 and the reactive uptake coefficient was calculated for a range of NO2 concentrations, peaking at 2.5×10-4 for 30 ppb NO2. Investigation of ammonium and sodium nitrate aerosols showed no measureable HONO production. Results from the TiO2 experiment were included in a box model for Beijing where, assuming all the observed aerosol surface area was pure TiO2, the HONO contribution from this aerosol source was modelled to be roughly 10% of the modelled concentration at midday. This model was not able to replicate the measured HONO data, however, indicating the need for other sources of HONO. As part of the atmospheric chemistry of amines project measurements of OH and HO2 were carried out at the EUPHORE chamber using LIF. The measured OH and OH calculated from the amine decay did not agree indicating either a possible interference from the amine oxidation products in the LIF system or in homogeneous air at the LIF and amine sampling ports. The measured HO2 in the dark was observed to have a lifetime exceeding 2 hours. This slow HO2 decay could not be reproduced by a kinetic model which predicted a HO2 lifetime of seconds suggesting an unknown a source of HO2 in the dark

IP forwarding alternatives in cell switched optical networks

Optical switching will enable core Internet packet switching to scale with future transmission rate increases. Currently proposed optical ATM switches do not allow packet reassembly, which is necessary for packet level forwarding. This results in the requirement to create end to end ATM virtual connections for flows even if they contain only one packet. In electronically switched networks MPOA and MPLS allow both cell and packet level forwarding to overcome this problem. This paper examines the feasibility of implementing such protocols over an optically switched network. Two different architectures are examined: use of an adjunct electrical router; and native optical packet reassembly. An examination of the optical reassembly buffer requirements show that the use of MPLS will require significantly more buffering than MPOA

An examination of IP/ATM cut-through forwarding in dynamically routed networks

Multiprotocol over ATM (MPOA), IP switching and multiprotocol label switching (MPLS) have distinctly different mechanisms for cut-through packet forwarding. MPOA and IP switching use flow-based cut-through (FBC) forwarding while MPLS uses routing table linked cut-through forwarding (TLC). This paper examines the sensitivity of each these cut-through forwarding mechanisms to changes in underlying routing tables. We examine a scenario where a congestion-sensitive dynamic routing protocol, such as OSPF optimised multipath, leads to frequently changing routing tables. We show that FBC forwarding reacts significantly worse than flow length distributions predict, taking up to 1200 seconds to react to route changes and forward at least 50% of packets on the new route. Flow characteristics are examined to determine ways to improve FBC sensitivity. We show that implementing a maximum flow length of 200 seconds improves the response to route changes significantly with a minimal decrease in the number of switched packets (1.5%)

Successful use of steroids and ureteric stents in 24 patients with idiopathic retroperitoneal fibrosis : a retrospective study

Original article can be found at : http://content.karger.com/ Copyright Karger [Full text of this article is not available in the UHRA]Background/Aims: Retroperitoneal fibrosis (RPF) is a chronic inflammatory disorder causing obstructive nephropathy and renal failure. We reviewed our management of this condition. Method: All patients with RPF treated at a single center over a 15-year period were identified. A full review of notes and computer records was undertaken. Results: Data was available on 27 patients, 3 of which were excluded from later analysis. Diagnosis was based on clinical history and cross-sectional imaging. Retroperitoneal biopsy was undertaken in 3 patients. 96% had significant renal impairment at presentation with a mean serum creatinine of 688 μmol/l. 46% required emergency hemodialysis. All patients were treated with a combination of ureteric stents and/or steroids with an excellent clinical response. The mean best creatinine reached by the cohort was 136 μmol/l, and renal function remained stable in the long term. No patients required chronic dialysis. Ureteric stents were removed within 12 months and low-dose steroids were continued for a mean of 34 months. Recurrent disease was observed in 25% of patients, who all responded well to further steroid therapy. Mean duration of follow-up was 76 months. Conclusions: RPF is very effectively treated by a combination of ureteric stents and steroids, with excellent long-term results using this approach. Continued follow-up is advised because of the possibility of recurrent disease.Peer reviewe

The Legal and Policy Road Ahead: An Analysis of Public Comments in NHTSA’s Vehicle-to-Vehicle Advance Notice of Proposed Rulemaking

As motor vehicle accidents have overwhelming human and economic costs, policy interventions that lower the risk of accidents have tremendous potential to improve public health and safety. One particularly promising innovation is Vehicle-to-Vehicle (V2V) communication technologies, which transmit information between nearby automobiles in order to warn drivers of an imminent collision. V2V communications may enable drivers to avoid or mitigate harmful accidents, but only if widely adopted. The National Highway Traffic Safety Administration (NHTSA) has begun planning for the implementation of V2V technology, and has recently completed the public comment period of an Advance Notice of Proposed Rulemaking (ANPRM) in preparation for rulemaking in this area. In this Article, we qualitatively and quantitatively analyze the public comments received by NHTSA in response to its ANPRM concerning V2V communications technologies. Over 800 individuals and groups responded to the ANPRM; almost ninety-five percent of comments were provided by members of the general public. We discuss major considerations articulated by various stakeholder groups, including industry, policy advocacy groups, and the public as a whole. In particular, we focus on three concerns identified by NHTSA as potential barriers to acceptance of V2V communications technology by both interested stakeholder groups and the public: implications for privacy, threats to security, and potential liability. We then discuss the implications of our analysis for public acceptance of V2V communications technology and NHTSA’s upcoming privacy impact assessment of V2V communications devices

Investigation and modelling of traffic issues in immersive audio environments

Copyright © 2004 IEEEA growing area of technical importance is that of distributed virtual environments for work and play. For the audio component of such environments to be useful, great emphasis must be placed on the delivery of high quality audio scenes in which participants may change their relative positions. In this paper we describe and analyze an algorithm focused on maintaining relative synchronization between multiple users of such an environment and examine the subjective quality of service achieved

The Long Winter of 1880-1881

The story of the winter of 1880-1881 in the central United States has been retold in historical fiction, including Laura Ingalls Wilder’s The Long Winter, as well as in local histories and folklore. What story does the meteorological data tell, and how does it measure up when compared to the fiction and folklore? What were the contributing factors to the severity of the Long Winter, and has it been or could it be repeated? Examining historical and meteorological data, reconstructions, and reanalysis, including the Accumulated Winter Season Severity Index, the Long Winter emerges as one of the most severe since European-descended settlers arrived to the central United States and began documenting weather. Contributing factors to its severity include an extremely negative North Atlantic Oscillation pattern, a mild to moderate El Niño, and a background climate state that was much colder than the twentieth-century average. The winter began early and was particularly cold and snowy throughout its duration, with a sudden spring melt that caused subsequent record-setting flooding. Historical accounts of the winter, including The Long Winter, prove to be largely accurate in describing its severity, as well as its impacts on transportation, fuel availability, food supplies, and human and livestock health. Being just one of the most severe winters on record, there are others in the modern historical record that do compare in severity, providing opportunity for comparing and contrasting the impacts of similarly severe winters

Undergraduate difficulties: algebraic skills and mathematical comprehension.

Many first year university students struggle with mathematics. Observations in senior mathematics classes in four New Zealand secondary schools highlighted potential undergraduate problems, especially with algebraic and mathematical reading skills. In this thesis, these two areas are investigated further. In the first part of the thesis, an analysis is done of algebraic tests given to first year university mathematics students. From the results there emerged five main categories of common consistent algebraic difficulties. These categories not only emerged the following year with a similar group, but senior secondary school and second year undergraduate mathematics students also displayed them. Overall, the conclusion was that these categories of algebraic difficulties formed from the research did not appear to improve with higher mathematical learning. A second area for the investigation of undergraduate difficulties was in the field of reading to learn mathematics. The results of a questionnaire survey confirmed that students were not only resistant to reading mathematical text, but they did not appear to have the skills to read expository text. Many students used a narrative, surface approach to mathematical reading that resulted in very little of a topic being understood. Further analysis using a variety of extracts, case studies, interviews and written answers led to the formation of a mathematical reading model based on generative comprehension research by Wittrock (1990) and interactive reading research by Dechant (1991). For mathematical text, critical linkages were often symbol-symbol linkages requiring a higher level of comprehension than narrative text. These critical linkages were predominantly located at an inner text layer. A major deterrent to reading mathematical text for students is the difficulty in locating these critical linkages in hard-copy text. Further investigations compared hard copy text with various types of software designed for self-study purposes. Some of the software was found to be better at directing students to these critical linkages while others were not so successful