Effect of ENSO phase on large-scale snow water equivalent distribution in a GCM

Understanding links between the El Nino-Southern Oscillation (ENSO) and snow would be useful for seasonal forecasting, but also for understanding natural variability and interpreting climate change predictions. Here, a 545-year run of the general circulation model HadCM3, with prescribed external forcings and fixed greenhouse gas concentrations, is used to explore the impact of ENSO on snow water equivalent (SWE) anomalies. In North America, positive ENSO events reduce the mean SWE and skew the distribution towards lower values, and vice versa during negative ENSO events. This is associated with a dipole SWE anomaly structure, with anomalies of opposite sign centered in western Canada and the central United States. In Eurasia, warm episodes lead to a more positively skewed distribution and the mean SWE is raised. Again, the opposite effect is seen during cold episodes. In Eurasia the largest anomalies are concentrated in the Himalayas. These correlations with February SWE distribution are seen to exist from the previous June-July-August (JJA) ENSO index onwards, and are weakly detected in 50-year subsections of the control run, but only a shifted North American response can be detected in the anaylsis of 40 years of ERA40 reanalysis data. The ENSO signal in SWE from the long run could still contribute to regional predictions although it would be a weak indicator onl

The Need for Greater Price Transparency in the Medical Device Industry: An Economic Analysis

Proposed legislation seeks to impose price transparency in the health care industry as a remedy for increasing medical device prices. This paper analyzes previous attempts to mandate similar price-disclosure rules in a variety of industries. We identify the economic conditions under which mandatory price disclosure is likely to generate substantial benefits and costs. Applying these conditions, we conclude that mandatory price disclosure for implantable devices is unlikely to pass a benefit-cost test.

Investigation of the influence of a step change in surface roughness on turbulent heat transfer

The use is studied of smooth heat flux gages on the otherwise very rough SSME fuel pump turbine blades. To gain insights into behavior of such installations, fluid mechanics and heat transfer data were collected and are reported for a turbulent boundary layer over a surface with a step change from a rough surface to a smooth surface. The first 0.9 m length of the flat plate test surface was roughened with 1.27 mm hemispheres in a staggered, uniform array spaced 2 base diameters apart. The remaining 1.5 m length was smooth. The effect of the alignment of the smooth surface with respect to the rough surface was also studied by conducting experiments with the smooth surface aligned with the bases or alternatively with the crests of the roughness elements. Stanton number distributions, skin friction distributions, and boundary layer profiles of temperature and velocity are reported and are compared to previous data for both all rough and all smooth wall cases. The experiments show that the step change from rough to smooth has a dramatic effect on the convective heat transfer. It is concluded that use of smooth heat flux gages on otherwise rough surfaces could cause large errors

Microwave Dielectric Heating of Drops in Microfluidic Devices

We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30 degrees C above the base temperature of the microfluidic device. Many common biological and chemical applications require rapid and local control of temperature, such as PCR amplification of DNA, and can benefit from this new technique.Comment: 6 pages, 4 figure

Exploration History and Mineral Potential of the Central Arctic Zn-Pb District, Nunavut

Exploration in the central Arctic Zn-Pb District took place in five phases: 1) an initial exploration period (1960–70), during which most surface showings on Cornwallis and Little Cornwallis islands were found; 2) a discovery period (1971–79), during which the buried Polaris ore body was discovered and its feasibility and viability established, new showings were found farther afield, and many showings received limited drill testing; 3) the production period (1980–88), dominated by drilling at Polaris Mine; 4) an ore-replacement exploration period (1989–2001), during which showings close to Polaris were extensively drilled, showings on Cornwallis Island drill tested, and new showings found and drilled farther away; and 5) a reclamation period (2002–05), during which the infrastructure was removed and the mine site restored. Factors affecting the timing and rate of exploration were generally intrinsic to the region: 1) discovery of showings in 1960, 2) discovery of the Polaris ore body in 1971, 3) declining reserves between 1989 and 2002, 4) closure of the mine in 2002, 5) the short exploration season and difficult logistics, and 6) lack of competition. The external drivers of exploration were 1) oil-related exploration that led to the discovery of the Polaris showings, 2) the onset of regional exploration coinciding with spikes in the price of zinc, and 3) the surge in scientific interest in carbonate-hosted Zn-Pb deposits in 1967. Probabilistic, discovery-time curve analysis indicates that over 50 showings remain undiscovered. Because logistics controlled the target selection, the standard assumption of a logical discovery process (from largest target to smallest target) is likely invalid. This means that large, untested targets may still exist in the district.Les travaux d’exploration dans le district de Zn-Pb du centre de l’Arctique se sont déroulés en cinq étapes : 1) une période d’exploration initiale (1960 - 1970), durant laquelle la plupart des traces détectées sur l’île Cornwallis et la Petite île Cornwallis ont été trouvées; 2) une période de découverte (1971- 1979), pendant laquelle la zone de minéralisation enterrée de Polaris a été découverte et sa faisabilité et sa rentabilité ont été déterminées, de nouvelles traces ont été décelées plus au loin, et de nombreuses traces ont fait l’objet d’un nombre restreint d’essais de foration; 3) une période de production (1980-1988), dominée par les travaux de foration à la mine Polaris; 4) une période d’exploration de remplacement de minerai (1989- 2001), dans le cadre de laquelle les traces situées à proximité de Polaris ont fait l’objet de forations intenses, les traces de l’île Cornwallis ont fait l’objet d’essais et de nouvelles traces ont été découvertes et forées plus loin; et 5) une période de remise en état (2002-2005), durant laquelle l’infrastructure a été retirée et l’emplacement de la mine a été restauré. Généralement, les facteurs touchant la programmation et le régime d’exploration étaient intrinsèques à la région : 1) la découverte des traces en 1960, 2) la découverte du corps minéralisé de Polaris en 1971, 3) la diminution des réserves entre 1989 et 2002, 4) la fermeture de la mine en 2002, 5) la courte saison d’exploration et la logistique qui présentait des difficultés, et 6) l’absence de concurrence. Les motifs externes à l’exploration étaient les suivants : 1) l’exploration pétrolière qui a engendré la découverte des traces de Polaris, 2) le début de l’exploration régionale qui coïncidait avec les variations brusques du prix du zinc, et 3) l’intérêt soudain, dans le monde scientifique, envers les gisements de Zn-Pb dans la roche hôte carbonatée en 1967. L’analyse probabiliste de la courbe de découverte par rapport au temps indique que plus d’une cinquantaine de traces n’ont toujours pas été découvertes. Puisque la logistique décidait du choix des cibles, il est très vraisemblable que l’hypothèse standard d’un processus de découverte logique (de la cible la plus grande à la cible la plus petite) ne soit pas valable. Cela signifie que de vastes cibles n’ayant pas fait l’objet d’essais existent encore dans le district

G80-521 Common Stalk Borer in Corn (Revised April 2000)

The life history and appearance of common stalk borers is described, along with information on damage they can cause, economic injury levels and ways to control them in corn. In the past, the common stalk borer, Papaipema nebris, has not been a major pest of corn in Nebraska. Stalk borer damage in corn commonly is confined to occasional plants in the first few rows near field margins, fence rows, grass terraces and waterways. In addition to attacking corn, this insect attacks over one hundred other species of plants, including ornamentals, broadleaf weeds and grasses. It may feed on soybeans as well, but is not an economically important pest of that crop. Understanding the common stalk borer life cycle and behavior is critical to selecting management practices to reduce its damage in corn

G80-521 Common Stalk Borer in Corn (Revised April 2000)

The life history and appearance of common stalk borers is described, along with information on damage they can cause, economic injury levels and ways to control them in corn. In the past, the common stalk borer, Papaipema nebris, has not been a major pest of corn in Nebraska. Stalk borer damage in corn commonly is confined to occasional plants in the first few rows near field margins, fence rows, grass terraces and waterways. In addition to attacking corn, this insect attacks over one hundred other species of plants, including ornamentals, broadleaf weeds and grasses. It may feed on soybeans as well, but is not an economically important pest of that crop. Understanding the common stalk borer life cycle and behavior is critical to selecting management practices to reduce its damage in corn