Detection of submillimeter polarization in the Orion Nebula

Linear polarization of the submillimeter (270 micron) continuum radiation from two regions of Orion was observed: one centered on the Kleinmann-Low Nebula and one centered on the 400 micron peak 1.5' south of the nebula. The polarizations measured for these regions are P = (1.7 +/-0.4)% at phi = 23 deg +/-7 deg and P=(1.7 +/- 0.5)% at phi = 27 deg +/- 7 deg respectively. A 2(sigma) upper limit, P or = 1.6%, was found for the nebular W3(OH). The position angle at KL is orthogonal to that measured at 11 microns by Dyck and Beichman and at 11 and 20 microns by Knacke and Capps. The far-IR values for KL reported by Gull et. al. (approx 2%) and by Cudlip et al. (1 to 2% level) are consistent with the submillimeter results

The Swiss National Bank's monetary policy concept - an example of a 'principles-based' policy framework

The practice of monetary policy has evolved a great deal since the early 1990s. This evolution was significantly influenced by rapid developments in the theory of monetary policy. A new consensus about 'principles-based' monetary policy appears to be emerging. It marries a firm long-term anchor for nominal stability, rooted in the original ideas behind inflation targeting, with short-term flexibility, based on a more discretionary and pragmatic approach to monetary policy. The SNB's monetary policy framework - with a firm nominal anchor but with an emphasis on the need for flexibility - reflects, to a considerable degree, the emerging academic consensus about best-practice monetary policy. With its successful seven-year track record, it may serve as an interesting case study for a policy aiming at an intermediate position between full discretion and rigidly defined short-term inflation targeting.Swiss National Bank, monetary policy, inflation targeting, rules, discretion

Is Explicit Congestion Notification usable with UDP?

We present initial measurements to determine if ECN is usable with UDP traffic in the public Internet. This is interesting because ECN is part of current IETF proposals for congestion control of UDPbased interactive multimedia, and due to the increasing use of UDP as a substrate on which new transport protocols can be deployed. Using measurements from the author’s homes, their workplace, and cloud servers in each of the nine EC2 regions worldwide, we test reachability of 2500 servers from the public NTP server pool, using ECT(0) and not-ECT marked UDP packets. We show that an average of 98.97% of the NTP servers that are reachable using not-ECT marked packets are also reachable using ECT(0) marked UDP packets, and that ~98% of network hops pass ECT(0) marked packets without clearing the ECT bits. We compare reachability of the same hosts using ECN with TCP, finding that 82.0% of those reachable with TCP can successfully negotiate and use ECN. Our findings suggest that ECN is broadly usable with UDP traffic, and that support for use of ECN with TCP has increased

Synchronous seasonal change in fin whale song in the North Pacific.

Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here

Acoustic Emission Linear Pulse Holography

This paper describes Acoustic Emission Linear Pulse Holography which combines the advantages of linear imaging and acoustic emission into a single NDE inspection system. This unique system produces a chronological linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. Conventional linear holographic imaging uses an ultrasonic transducer to transmit energy into the volume being imaged. When the crack or defect reflects that energy, the crack acts as a new source of acoustic waves. To formulate an image of that source, a receiving transducer is scanned over the volume of interest and the phase of the received signals is measured at successive points on the scan. The innovation proposed in this paper is the utilization of the crack generated acoustic emission as the acoustic source and generation of a line image of the crack as it grows. A thirty-two point sampling array is used to construct phase-only linear holograms of simulated acoustic emission sources on large metal plates. The phases are calculated using the pulse time-of-flight (TOF) times from the reference transducer to the array of receivers. Computer reconstruction of the image is accomplished using a one-dimensional FFT algorithm (i.e., backward wave). Experimental results are shown which graphically illustrate the unique acoustic emission images of a single point and a linear crack in a 100 mm × 1220 mm × 1220 mm aluminum plate

Incidence, Characteristics, and Outcomes of Acute Kidney Injury Treated with Dialysis during Pregnancy and the Postpartum Period

Pregnancy-related acute kidney injury (AKI) may be associated with significant morbidity and mortality in young and often otherwise healthy women. We conducted a retrospective cohort study of all consecutive pregnancies between 1997 and 2011 in Ontario and describe the incidence, characteristics, and outcomes of AKI treated with dialysis (AKI-D) during pregnancy or within 12 weeks postpartum. Of 1,918,789 pregnancies, 188 were complicated by AKI-D (incidence proportion: 1 per 10,000, 95% confidence interval 0.8 to 1.1). Eight women died (4.3% versus 0.01% in the general population) and seven (3.9%) survivors remained dialysis-dependent four months after delivery. The presence of AKI-D was associated with several maternal complications as well as low birth weight, small for gestational age, and preterm birth among infants, although there were no stillbirths and fewer than five neonatal deaths in affected pregnancies. In conclusion, AKI-D in pregnancy is rare. Most affected women and their babies have good short-term outcomes

Underwater radiated noise levels of a research icebreaker in the central Arctic Ocean

U.S. Coast Guard Cutter Healy\u27s underwater radiated noise signature was characterized in the central Arctic Ocean during different types of ice-breaking operations. Propulsion modes included transit in variable ice cover, breaking heavy ice with backing-and-ramming maneuvers, and dynamic positioning with the bow thruster in operation. Compared to open-water transit, Healy\u27s noise signature increased approximately 10 dB between 20 Hz and 2 kHz when breaking ice. The highest noise levels resulted while the ship was engaged in backing-and-ramming maneuvers, owing to cavitation when operating the propellers astern or in opposing directions. In frequency bands centered near 10, 50, and 100 Hz, source levels reached 190–200 dB re: 1 μPa at 1 m (full octave band) during ice-breaking operations

Far-Infrared Spectral Energy Distributions and Photometric Redshifts of Dusty Galaxies

We infer the large-scale source parameters of dusty galaxies from their observed spectral energy distributions (SEDs) using the analytic radiative transfer methodology presented in Chakrabarti & McKee (2005). For local ultra-luminous infrared galaxies (ULIRGs), we show that the millimeter to far-infrared (FIR) SEDs can be well fit using the standard dust opacity index of 2 when self-consistent radiative transfer solutions are employed, indicating that the cold dust in local ULIRGs can be described by a single grain model. We develop a method for determining photometric redshifts of ULIRGs and sub-mm galaxies from the millimeter-FIR SED; the resulting value of $1+z$ is typically accurate to about 10%. As such, it is comparable to the accuracy of near-IR photometric redshifts and provides a complementary means of deriving redshifts from far-IR data, such as that from the upcoming $\it{Herschel Space Observatory}$. Since our analytic radiative transfer solution is developed for homogeneous, spherically symmetric, centrally heated, dusty sources, it is relevant for infrared bright galaxies that are primarily powered by compact sources of luminosity that are embedded in a dusty envelope. We discuss how deviations from spherical symmetry may affect the applicability of our solution, and we contrast our self-consistent analytic solution with standard approximations to demonstrate the main differences.Comment: 37 pages, 14 Figures, 3 Tables, submitted to ApJ. submitted to Ap

An Unusual Root Injury on Jersey-type Sweetpotatoes in 1962

Volume: 4