Collars and partitions of hyperbolic cone-surfaces

For compact Riemann surfaces, the collar theorem and Bers' partition theorem are major tools for working with simple closed geodesics. The main goal of this paper is to prove similar theorems for hyperbolic cone-surfaces. Hyperbolic two-dimensional orbifolds are a particular case of such surfaces. We consider all cone angles to be strictly less than $\pi$ to be able to consider partitions.Comment: 11 pages, 9 figures; v2: minor changes, to appear in Geometriae Dedicat

Making tomorrow's mistakes today: Evolutionary prototyping for risk reduction and shorter development time

In the early days of JPL's solar system exploration, each spacecraft mission required its own dedicated data system with all software applications written in the mainframe's native assembly language. Although these early telemetry processing systems were a triumph of engineering in their day, since that time the computer industry has advanced to the point where it is now advantageous to replace these systems with more modern technology. The Space Flight Operations Center (SFOC) Prototype group was established in 1985 as a workstation and software laboratory. The charter of the lab was to determine if it was possible to construct a multimission telemetry processing system using commercial, off-the-shelf computers that communicated via networks. The staff of the lab mirrored that of a typical skunk works operation -- a small, multi-disciplinary team with a great deal of autonomy that could get complex tasks done quickly. In an effort to determine which approaches would be useful, the prototype group experimented with all types of operating systems, inter-process communication mechanisms, network protocols, packet size parameters. Out of that pioneering work came the confidence that a multi-mission telemetry processing system could be built using high-level languages running in a heterogeneous, networked workstation environment. Experience revealed that the operating systems on all nodes should be similar (i.e., all VMS or all PC-DOS or all UNIX), and that a unique Data Transport Subsystem tool needed to be built to address the incompatibilities of network standards, byte ordering, and socket buffering. The advantages of building a telemetry processing system based on emerging industry standards were numerous: by employing these standards, we would no longer be locked into a single vendor. When new technology came to market which offered ten times the performance at one eighth the cost, it would be possible to attach the new machine to the network, re-compile the application code, and run. In addition, we would no longer be plagued with lack of manufacturer support when we encountered obscure bugs. And maybe, hopefully, the eternal elusive goal of software portability across different vendors' platforms would finally be available. Some highlights of our prototyping efforts are described

Refractory Materials for Flame Deflector Protection

Fondu Fyre (FF) is currently the only refractory material qualified for use in the flame trench at KSC's Shuttle Launch Pads 39A and 3913. However, the material is not used as it was qualified and has undergone increasingly frequent and severe degradation due to the launch blasts. This degradation is costly as well as dangerous for launch infrastructure, crew and vehicle. The launch environment at KSC is unique. The refractory material is subject to the normal seacoast environment, is completely saturated with water before launch, and is subjected to vibrations and aggressive heat/blast conditions during launch. This report presents results comparing two alternate materials, Ultra-Tek FS gun mix and Kruzite GR Plus, with Fondu Fyre. The materials were subjected to bulk density, porosity, compression strength, modulus of rupture and thermal shock tests. In addition, test specimens were exposed to conditions meant to simulate the launch environment at KSC to help better understand how the materials will perform once installed

Launch Pad Flame Trench Refractory Materials

The launch complexes at NASA's John F. Kennedy Space Center (KSC) are critical support facilities for the successful launch of space-based vehicles. These facilities include a flame trench that bisects the pad at ground level. This trench includes a flame deflector system that consists of an inverted, V-shaped steel structure covered with a high temperature concrete material five inches thick that extends across the center of the flame trench. One side of the "V11 receives and deflects the flames from the orbiter main engines; the opposite side deflects the flames from the solid rocket boosters. There are also two movable deflectors at the top of the trench to provide additional protection to shuttle hardware from the solid rocket booster flames. These facilities are over 40 years old and are experiencing constant deterioration from launch heat/blast effects and environmental exposure. The refractory material currently used in launch pad flame deflectors has become susceptible to failure, resulting in large sections of the material breaking away from the steel base structure and creating high-speed projectiles during launch. These projectiles jeopardize the safety of the launch complex, crew, and vehicle. Post launch inspections have revealed that the number and frequency of repairs, as well as the area and size of the damage, is increasing with the number of launches. The Space Shuttle Program has accepted the extensive ground processing costs for post launch repair of damaged areas and investigations of future launch related failures for the remainder of the program. There currently are no long term solutions available for Constellation Program ground operations to address the poor performance and subsequent failures of the refractory materials. Over the last three years, significant liberation of refractory material in the flame trench and fire bricks along the adjacent trench walls following Space Shuttle launches have resulted in extensive investigations of failure mechanisms, load response, ejected material impact evaluation, and repair design analysis (environmental and structural assessment, induced environment from solid rocket booster plume, loads summary, and repair integrity), assessment of risk posture for flame trench debris, and justification of flight readiness rationale. Although the configuration of the launch pad, water and exhaust direction, and location of the Mobile Launcher Platform between the flame trench and the flight hardware should protect the Space Vehicle from debris exposure, loss of material could cause damage to a major element of the ground facility (resulting in temporary usage loss); and damage to other facility elements is possible. These are all significant risks that will impact ground operations for Constellation and development of new refractory material systems is necessary to reduce the likelihood of the foreign object debris hazard during launch. KSC is developing an alternate refractory material for the launch pad flame trench protection system, including flame deflector and flame trench walls, that will withstand launch conditions without the need for repair after every launch, as is currently the case. This paper will present a summary of the results from industry surveys, trade studies, life cycle cost analysis, and preliminary testing that have been performed to support and validate the development, testing, and qualification of new refractory materials

Authors’ Reply to “Training and Supporting Residents, for All Family Medicine Practice Settings.”

TO THE EDITOR: We appreciate Dr Wu’s comments and agree wholeheartedly that meeting community needs and negotiating relationships are essential skills for all family physicians. The need for these skills is amplified in the intimacy of the rural environment, as physicians navigate daily life amongst patients at grocery stores, restaurants, schools, and social gatherings

Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC)

Cardiac safety of dual anti-HER2 blockade with pertuzumab plus trastuzumab in early HER2-positive breast cancer in the APHINITY trial.

BACKGROUND Trastuzumab increases the incidence of cardiac events (CEs) in patients with breast cancer (BC). Dual blockade with pertuzumab (P) and trastuzumab (T) improves BC outcomes and is the standard of care for high-risk human epidermal growth factor receptor 2 (HER2)-positive early BC patients. We analyzed the cardiac safety of P and T in the phase III APHINITY trial. PATIENTS AND METHODS Left ventricular ejection fraction (LVEF) ≥ 55% was required at study entry. LVEF assessment was carried out every 3 months during treatment, every 6 months up to month 36, and yearly up to 10 years. Primary CE was defined as heart failure class III/IV and a significant decrease in LVEF (defined as ≥10% from baseline and to <50%), or cardiac death. Secondary CE was defined as a confirmed significant decrease in LVEF, or CEs confirmed by the cardiac advisory board. RESULTS The safety analysis population consisted of 4769 patients. With 74 months of median follow-up, CEs were observed in 159 patients (3.3%): 83 (3.5%) in P + T and 76 (3.2%) in T arms, respectively. Most CEs occurred during anti-HER2 therapy (123; 77.4%) and were asymptomatic or mildly symptomatic decreases in LVEF (133; 83.6%). There were two cardiac deaths in each arm (0.1%). Cardiac risk factors indicated were age > 65 years, body mass index ≥ 25 kg/m2, baseline LVEF between 55% and <60%, and use of an anthracycline-containing chemotherapy regimen. Acute recovery from a CE based on subsequent LVEF values was observed in 127/155 patients (81.9%). CONCLUSIONS Dual blockade with P + T does not increase the risk of CEs compared with T alone. The use of anthracycline-based chemotherapy increases the risk of a CE; hence, non-anthracycline chemotherapy may be considered, particularly in patients with cardiovascular risk factors