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1

Compare and Contrast Warm and Cold Fronts  

NSDL National Science Digital Library

In weather, fronts are defined as the boundaries between different air masses. Depending on the direction of movement and the characteristics of the air involved, different types of fronts form. This visualization shows the movement of warm and cold fronts as well as the characteristic clouds that are generated by each. A background essay and discussion questions are included.

2

Cold thoughts on nuclear winter  

SciTech Connect

The nuclear winter controversy is a notorious example of the politicization of science. Large firestorms are followed by soot-laden black rain. It is not known what fraction of the soot produced by fires is removed from the atmosphere in this manner. A simple argument suggests that the fraction may be large. It is even possible to argue that a severe nuclear winter is not self-consistent. It is often assumed that carbonaceous soot is chemically inert in the atmosphere, despite the presence of trace amounts of chemically active species. Even if the magnitude of the nuclear winter effect were known, its implications would remain controversial. Nuclear winter chillings are usually measured as drops in mean temperature. However, reduction in solar heating reduces the diurnal variation as well.

Katz, J.I.

1987-01-01

3

Cold thoughts on nuclear winter  

Microsoft Academic Search

The nuclear winter controversy is a notorious example of the politicization of science. Large firestorms are followed by soot-laden black rain. It is not known what fraction of the soot produced by fires is removed from the atmosphere in this manner. A simple argument suggests that the fraction may be large. It is even possible to argue that a severe

Katz

1987-01-01

4

Different Methods of Forming Cold Fronts in Nonmerging Clusters  

NASA Astrophysics Data System (ADS)

Sharp edges in X-ray surface brightness with continuous gas pressure called cold fronts have often been found in relaxed galaxy clusters such as Abell 496. Models that explain cold fronts as surviving cores of head-on subcluster mergers do not work well for these clusters, and competing models involving gas sloshing have been recently proposed. Here, we test some concrete predictions of these models in a combined analysis of density, temperature, metal abundances, and abundance ratios in a deep Chandra exposure of Abell 496. We confirm that the chemical discontinuities found in this cluster are not consistent with a core merger remnant scenario. However, we find chemical gradients across a spiral ``arm'' discovered at 73 kpc north of the cluster center and coincident with the sharp edge of the main cold front in the cluster. Despite the overall SN Ia iron mass fraction dominance found within the cooling radius of this cluster, the metal enrichment along the arm, determined from silicon and iron abundances, is consistent with a lower SN Ia iron mass fraction (51%+/-14%) than that measured in the surrounding regions (85%+/-14%). The ``arm'' is also significantly colder than the surroundings by 0.5-1.6 keV. The arm extends from a boxy colder region surrounding the center of the cluster, where two other cold fronts are found. This cold arm is a prediction of current high resolution numerical simulations as a result of an off-center encounter with a less massive pure dark matter halo, and we suggest that the cold fronts in A496 provide the first clear corroboration of such model, where the closest encounter happened ~0.5 Gyr ago. We also argue for a possible candidate dark matter halo responsible for the cold fronts in the outskirts of A496.

Dupke, Renato; White, Raymond E., III; Bregman, Joel N.

2007-12-01

5

Cold Fronts in Clusters of Galaxies: Observations and Modeling  

NASA Technical Reports Server (NTRS)

Mergers of galaxy clusters -- some of the most energetic events in the Universe -- produce disturbances in hot intracluster medium, such as shocks and cold fronts, that can be used as tools to study the physics of galaxy clusters. Cold fronts may constrain viscosity and the structure and strength of the cluster magnetic fields. Combined with radio data, these observations also shed light on the production of ultrarelativistic particles that are known to coexist with the cluster thermal plasma. This talk will summarize the current X-ray observations of cluster mergers, as well as some recent radio data and high resolution hydrodynamic simulations.

Markevitch, Maxim

2012-01-01

6

ALMA Front-End Verification Using a Dry Cold Load  

NASA Astrophysics Data System (ADS)

Several techniques for measuring the radiometric temperature (brightness) of a refrigerated dry calibration load for ALMA front-end verification are presented. The brightness of the load including the effects of the cryostat window is estimated using different techniques and compared at frequencies up to 1 THz. The measured results are compared with those obtained by a conventional calibration technique using the ALMA front-end. The estimated brightness shows a good agreement at lower ALMA bands (below 400 GHz) with increased deviation at higher frequencies. Measured noise temperatures of the ALMA front-end using a wet LN2 load and the dry cold load are also presented.

Lee, Y.; Ellison, B.; Huggard, P.; Harman, M.; Boughriet, A.; Bartynowski, W.; Oldfield, M.; Morris, N.; Hekman, P.; Tan, G. H.

2010-03-01

7

Effects of cold fronts on MODIS-derived sensible and latent heat fluxes in Itumbiara reservoir (Central Brazil)  

NASA Astrophysics Data System (ADS)

In this work we investigate the cold front passage effects on sensible and latent heat flux in a tropical hydroelectric reservoir. The study area, Itumbiara reservoir (Goiás State/Brazil) at the beginning of the austral winter, is characterized by the presence of a weak thermal stratification and the passage of several cold fronts from higher latitudes of South America. Sensible and latent heat fluxes were estimated considering the atmospheric boundary layer stability. In situ and MODIS water surface temperature data were used to adjust the coefficients for momentum and heat exchanges between water and atmosphere and spatialize the sensible and latent heat fluxes. The results showed that during a cold front event the sensible heat flux can be up to five times greater than the flux observed before. The latent heat flux tends to decrease during the cold front but increase again after the passage. The highest values of heat loss were observed at littoral zone and some Reservoir's embayment. The heat loss intensification can be separated in two moments: first, during the cold front passage, when the wind speed increases and the air temperature decreases; second, after the cold front passage, with air humidity decreasing. This can be considered a key process to understanding the heat loss in the Itumbiara reservoir.

Curtarelli, Marcelo; Alcântara, Enner; Rennó, Camilo; Stech, José

2013-11-01

8

Fast Simulations of Gas Sloshing and Cold Front Formation  

NASA Technical Reports Server (NTRS)

We present a simplified and fast method for simulating minor mergers between galaxy clusters. Instead of following the evolution of the dark matter halos directly by the N-body method, we employ a rigid potential approximation for both clusters. The simulations are run in the rest frame of the more massive cluster and account for the resulting inertial accelerations in an optimised way. We test the reliability of this method for studies of minor merger induced gas sloshing by performing a one-to-one comparison between our simulations and hydro+N-body ones. We find that the rigid potential approximation reproduces the sloshing-related features well except for two artifacts: the temperature just outside the cold fronts is slightly over-predicted, and the outward motion of the cold fronts is delayed by typically 200 Myr. We discuss reasons for both artifacts.

Roediger, E.; ZuHone, J. A.

2012-01-01

9

Fast Simulations of Gas Sloshing and Cold Front Formation  

NASA Technical Reports Server (NTRS)

We present a simplified and fast method for simulating minor mergers between galaxy clusters. Instead of following the evolution of the dark matter halos directly by the N-body method, we employ a rigid potential approximation for both clusters. The simulations are run in the rest frame of the more massive cluster and account for the resulting inertial accelerations in an optimised way. We test the reliability of this method for studies of minor merger induced gas sloshing by performing a one-to-one comparison between our simulations and hydro+N-body ones. We find that the rigid potential approximation reproduces the sloshing-related features well except for two artefacts: the temperature just outside the cold fronts is slightly over-predicted, and the outward motion of the cold fronts is delayed by typically 200 Myr. We discuss reasons for both artefacts.

Roediger, E.; ZuHone, J. A.

2011-01-01

10

Sloshing cold fronts in the IC1860 group .  

NASA Astrophysics Data System (ADS)

We present a combined X-ray, optical, and radio analysis of the galaxy group IC 1860 using the currently available Chandra and XMM data, literature multi-object spectroscopy data and GMRT data. The Chandra and XMM data reveal two surface brightness discontinuities at 45 and 76 kpc shown to be consistent with a pair of cold fronts. We find evidence of a characteristic spiral pattern in the X-ray gas distribution, tilted with respect to the plane of the sky, indicative of a mainly line-of-sight off-axis merger responsible for the sloshing. We identify the likely perturber as an optically disturbed spiral galaxy, IC 1859. The peculiar velocity of the BCG with respect to the mean group velocity is another signature consistent with the sloshing scenario. The GMRT observation at 325 MHz shows extended radio emission: one component is contained within the inner cold front as seen in some galaxy clusters, whereas the second component is detached and in the vicinity of the spiral feature. The limits obtained from the NVSS at 1.4 GHz point to a very steep spectral emission coming from aged radio plasma. The evidence presented in this study is among the strongest supporting the currently favored model of cold front formation in relaxed objects and establishes the group scale as a chief environment to study this phenomenon.

Gastaldello, F.; Di Gesu, L.; Ghizzardi, S.; Giacintucci, S.; Girardi, M.; Roediger, E.; Rossetti, M.

11

On the movement and low-level structure of cold fronts  

NASA Technical Reports Server (NTRS)

Factors that are pertinent to the cold-front motion were examined using the results from previous studies of the low-level structure of cold fronts. Observational studies indicate the existence of two different types of behavior for a cold front. These types of behavior were related to the results of recent theoretical studies, and the mechanism responsible for front propagation was elucidated. It is shown that a necessary requirement for propagation is the existence of an alongfront temperature gradient.

Smith, Roger K.; Reeder, Michael J.

1988-01-01

12

Substructure in the Cold Front Cluster Abell 3667  

NASA Astrophysics Data System (ADS)

We present evidence for the existence of significant substructure in the cold front cluster Abell 3667 based on multiobject spectroscopy taken with the 3.9 m Anglo-Australian Telescope. This paper is the second in a series analyzing the relationship between cold fronts observed in Chandra X-ray images and merger activity observed at optical wavelengths. We have obtained 910 galaxy redshifts in the field of Abell 3667 out to 3.5 Mpc, of which 550 are confirmed cluster members, more than doubling the number of spectroscopically confirmed members previously available and probing some 3 mag down the luminosity function. From this sample, we derive a cluster redshift of z = 0.0553 ± 0.0002 and velocity dispersion of 1056 ± 38 km s-1 and use a number of statistical tests to search for substructure. We find significant evidence for substructure in the spatial distribution of member galaxies and also in the localized velocity distributions and, in spite of this evidence, find the global velocity distribution does not deviate significantly from a Gaussian. Using combined spatial and velocity information, we found the cluster can be separated into two major structures, with roughly equal velocity dispersions, but offset in peculiar velocity from each other by ~500 km s-1, and a number of minor substructures. We propose two scenarios which explain the radio and X-ray observations. Our data show the cold front is directly related to cluster merger activity, and also highlights the extent of optical data required to unambiguously detect the presence of substructure.

Owers, Matt S.; Couch, Warrick J.; Nulsen, Paul E.J.

2009-03-01

13

On a theory of the evolution of surface cold fronts  

NASA Technical Reports Server (NTRS)

The governing vorticity and divergence equations in the surface layer are derived and the roles of the different terms and feedback mechanisms are investigated in semigeostrophic and nongeostrophic cold-frontal systems. A planetary boundary layer model is used to perform sensitivity tests to determine that in a cold front the ageostrophic feedback mechanism as defined by Orlanski and Ross tends to act as a positive feedback mechanism, enhancing vorticity and convergence growth. Therefore, it cannot explain the phase shift between convergence and vorticity as simulated by Orlanski and Ross. An alternative plausible, though tentative, explanation in terms of a gravity wave is offered. It is shown that when the geostrophic deformation increases, nonlinear terms in the divergence equation may become important and further destabilize the system.

Levy, Gad; Bretherton, Christopher S.

1987-01-01

14

New Perspectives on Intermountain Cyclones and Cold Fronts  

NASA Astrophysics Data System (ADS)

The topography in and around the Intermountain West strongly affects the genesis, migration, and lysis of extratropical cyclones and cold fronts. In this presentation, we summarize new perspectives on Intermountain cyclone and cold-front evolution derived from recent climatological, observational, and modeling studies based on high-density observations and high-resolution reanalyses and numerical simulations. Recent high-resolution reanalyses show that Intermountain cyclone activity is greatest in two distinct regions. The first, which we call the Great Basin cyclone region, extends northeastward from the southern high Sierra to the Great Salt Lake Basin of northwest Utah. The second, which we call the Canyonlands cyclone region, lies over the upper Colorado River Basin of southeast Utah, a lowland region between the mountains and plateaus of central Utah and the Colorado Rockies. Composites of strong Intermountain cyclones generated in cross-Sierra (210-300°) 500-hPa flow show that cyclogenesis is preceeded by the development of the Great Basin Confluence Zone (GBCZ), a regional airstream boundary that extends downstream from the Sierra Nevada. Cyclogenesis occurs along the GBCZ as large-scale ascent develops over the Intermountain West in advance of an approaching upper-level trough. Flow splitting around the high Sierra and the presence of low-level baroclinity along the GBCZ suggest that Intermountain Cyclogenesis might be better conceptualized from a potential vorticity perspective than from traditional quasigeostrophic models of lee cyclogenesis. Surface observations indicate that the frequency of strong cold-frontal passages increases dramatically from the Cascade-Sierra Mountains to northern Utah, suggesting that the Intermountain West is a frequent cold-frontal breeding ground. Two case studies help illustrate the mechanisms contributing to these strong cold-frontal passages. During the 2002 Tax Day Cyclone, strong contraction (i.e., deformation and convergence) along the GBCZ forms an airstream boundary that is initially non-frontal, but becomes the locus for surface frontogenesis as it collects and concentrates baroclinity from the northern Great Basin. During the 25 March 2006 event, a highly mobile frontal system that moves discretely across the Sierra-Cascade Mountains and western Nevada and develops rapidly over eastern Nevada. Numerical sensitivity studies indicate that the the interaction of southwesterly pre-frontal flow with the formidable southern High Sierra produces a leeward orographic warm anomaly that enhances the cross-front temperature contrast.

Steenburgh, W. J.; West, G.; Neuman, C.; Shafer, J.; Jeglum, M.; Bosart, L. F.; Lee, T.

2011-12-01

15

Cold fronts and reservoir limnology: an integrated approach towards the ecological dynamics of freshwater ecosystems.  

PubMed

In this paper the authors discuss the effects of cold fronts on the dynamics of freshwater ecosystems of southeast South America. Cold fronts originating from the Antarctic show a monthly frequency that promotes turbulence and vertical mixing in reservoirs with a consequence to homogenize nutrient distribution, dissolved oxygen and temperature. Weak thermoclines and the athelomixis process immediately before, during and after the passage of cold fronts interfere with phytoplankton succession in reservoirs. Cyanobacteria blooms in eutrophic reservoirs are frequently connected with periods of stratification and stability of the water column. Cold fronts in the Amazon and Pantanal lakes may produce fish killings during the process of "friagem" associated mixing events. Further studies will try to implement a model to predict the impact of cold fronts and prepare management procedures in order to cope with cyanobacteria blooms during warm and stable water column periods. Changes in water quality of reservoirs are expected during circulation periods caused by cold fronts. PMID:21085786

Tundisi, J G; Matsumura-Tundisi, T; Pereira, K C; Luzia, A P; Passerini, M D; Chiba, W A C; Morais, M A; Sebastien, N Y

2010-10-01

16

Habitat suitability index models: greater white-fronted goose (wintering). [Anser albifrons  

SciTech Connect

A review and synthesis of available information were used to develop models for indexing the potential suitability of agricultural and natural wetland habitats for wintering white-fronted geese (Anser albifrons). The model is scaled to produce indices of habitat suitability from 0 (unsuitable habitat) to 1.0 (optimal habitat) primarily for wintering habitat in southwest Louisiana and southwest Texas. Habitat suitability indices are designed for use with Habitat Evaluations Procedures previously developed by the US Fish and Wildlife Service.

Kaminski, R.M.

1986-07-01

17

Winter habitat preferences for Florida manatees and vulnerability to cold.  

PubMed

To survive cold winter periods most, if not all, Florida manatees rely on warm-water refuges in the southern two-thirds of the Florida peninsula. Most refuges are either warm-water discharges from power plant and natural springs, or passive thermal basins that temporarily trap relatively warm water for a week or more. Strong fidelity to one or more refuges has created four relatively discrete Florida manatee subpopulations. Using statewide winter counts of manatees from 1999 to 2011, we provide the first attempt to quantify the proportion of animals using the three principal refuge types (power plants, springs, and passive thermal basins) statewide and for each subpopulation. Statewide across all years, 48.5% of all manatees were counted at power plant outfalls, 17.5% at natural springs, and 34.9 % at passive thermal basins or sites with no known warm-water features. Atlantic Coast and Southwest Florida subpopulations comprised 82.2% of all manatees counted (45.6% and 36.6%, respectively) with each subpopulation relying principally on power plants (66.6% and 47.4%, respectively). The upper St. Johns River and Northwest Florida subpopulations comprised 17.8% of all manatees counted with almost all animals relying entirely on springs (99.2% and 88.6% of those subpopulations, respectively). A record high count of 5,076 manatees in January 2010 revealed minimum sizes for the four subpopulations of: 230 manatees in the upper St. Johns River; 2,548 on the Atlantic Coast; 645 in Northwest Florida; and 1,774 in Southwest Florida. Based on a comparison of carcass recovery locations for 713 manatees killed by cold stress between 1999 and 2011 and the distribution of known refuges, it appears that springs offer manatees the best protection against cold stress. Long-term survival of Florida manatees will require improved efforts to enhance and protect manatee access to and use of warm-water springs as power plant outfalls are shut down. PMID:23527063

Laist, David W; Taylor, Cynthia; Reynolds, John E

2013-01-01

18

Winter Habitat Preferences for Florida Manatees and Vulnerability to Cold  

PubMed Central

To survive cold winter periods most, if not all, Florida manatees rely on warm-water refuges in the southern two-thirds of the Florida peninsula. Most refuges are either warm-water discharges from power plant and natural springs, or passive thermal basins that temporarily trap relatively warm water for a week or more. Strong fidelity to one or more refuges has created four relatively discrete Florida manatee subpopulations. Using statewide winter counts of manatees from 1999 to 2011, we provide the first attempt to quantify the proportion of animals using the three principal refuge types (power plants, springs, and passive thermal basins) statewide and for each subpopulation. Statewide across all years, 48.5% of all manatees were counted at power plant outfalls, 17.5% at natural springs, and 34.9 % at passive thermal basins or sites with no known warm-water features. Atlantic Coast and Southwest Florida subpopulations comprised 82.2% of all manatees counted (45.6% and 36.6%, respectively) with each subpopulation relying principally on power plants (66.6% and 47.4%, respectively). The upper St. Johns River and Northwest Florida subpopulations comprised 17.8% of all manatees counted with almost all animals relying entirely on springs (99.2% and 88.6% of those subpopulations, respectively). A record high count of 5,076 manatees in January 2010 revealed minimum sizes for the four subpopulations of: 230 manatees in the upper St. Johns River; 2,548 on the Atlantic Coast; 645 in Northwest Florida; and 1,774 in Southwest Florida. Based on a comparison of carcass recovery locations for 713 manatees killed by cold stress between 1999 and 2011 and the distribution of known refuges, it appears that springs offer manatees the best protection against cold stress. Long-term survival of Florida manatees will require improved efforts to enhance and protect manatee access to and use of warm-water springs as power plant outfalls are shut down.

Laist, David W.; Taylor, Cynthia; Reynolds, John E.

2013-01-01

19

A link between reduced Barents-Kara sea ice and cold winter extremes over northern continents  

Microsoft Academic Search

The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, as for example, extremely cold winter 2005–2006 in Europe and northern Asia. Here we show that anomalous decrease of wintertime sea ice concentration in the Barents-Kara (B-K) seas could bring about extreme cold events like winter 2005–2006. Our simulations with the ECHAM5 general circulation model demonstrate

Vladimir Petoukhov; Vladimir A. Semenov

2010-01-01

20

Finescale Vertical Structure of a Cold Front as Revealed by an Airborne Doppler Radar  

Microsoft Academic Search

In the afternoon of 24 May 2002, a well-defined and frontogenetic cold front moved through the Texas panhandle. Detailed observations from a series of platforms were collected near the triple point between this cold front and a dryline boundary. This paper primarily uses reflectivity and Doppler velocity data from an airborne 95-GHz radar, as well as flight-level thermodynamic data, to

Bart Geerts; Rick Damiani; Samuel Haimov

2006-01-01

21

Snow's No Problem! Winter Fun for Climates Cold and Hot.  

ERIC Educational Resources Information Center

Several winter activities and resources about winter activities are described for adaptation by teachers, regardless of the particular climate of the area. Included are descriptions of activities in language arts, social studies, mathematics, science, art, motor skills, and outdoor education. (CB)

Bang-Jensen, Valerie

1987-01-01

22

Metal jumps across sloshing cold fronts: The case of A 496  

NASA Astrophysics Data System (ADS)

Cold-fronts in cool-core clusters are thought to be induced by minor mergers and to develop through a sloshing mechanism. While temperature and surface-brightness jumps have been detected and measured in many systems, a detailed characterization of the metal abundance across the discontinuity is only available for a handful of objects. Within the sloshing scenario, we expect the central cool and metal rich gas to be displaced outwards into lower abundance regions, thus generating a metal discontinuity across the front. We analyzed a long (120 ks) XMM-Newton observation of A 496 to study the metal distribution and its correlation with the cold-fronts. We find Fe discontinuities across the two main cold-fronts located ˜ 60 kpc NNW and ˜ 160 kpc south of the peak and a metal excess in the south direction.

Ghizzardi, S.; De Grandi, S.; Molendi, S.

2013-04-01

23

Recent warm and cold daily winter temperature extremes in the Northern Hemisphere  

NASA Astrophysics Data System (ADS)

The winters of 2009-2010 and 2010-2011 brought frigid temperatures to parts of Europe, Russia, and the U.S. We analyzed regional and Northern Hemispheric (NH) daily temperature extremes for these two consecutive winters in the historical context of the past 63 years. While some parts clearly experienced very cold temperatures, the NH was not anomalously cold. Extreme warm events were much more prevalent in both magnitude and spatial extent. Importantly, the persistent negative state of the North Atlantic Oscillation (NAO) explained the bulk of the observed cold anomalies, however the warm extremes were anomalous even accounting for the NAO and also considering the states of the Pacific Decadal Oscillation (PDO) and El Niño Southern Oscillation (ENSO). These winters' widespread and intense warm extremes together with a continuing hemispheric decline in cold snap activity was a pattern fully consistent with a continuation of the warming trend observed in recent decades.

Guirguis, Kristen; Gershunov, Alexander; Schwartz, Rachel; Bennett, Stephen

2011-09-01

24

Blood pressure and thermal responses to repeated whole body cold exposure: effect of winter clothing  

Microsoft Academic Search

The effect of outdoor clothing and repeated cold exposure on blood pressure, heart rate, skin temperature, and thermal sensation\\u000a was studied in 16 young (18–34 years) and 8 middle-aged (35–51 years) normotensive participants. Four winter clothing ensembles\\u000a were used: regular winter clothing without a hat, with a hat, with an extra pair of pants, and with a hat and an extra pair

Yue Li; Hisham Alshaer; Geoff Fernie

2009-01-01

25

Modeling the effects of cold front passages on the heat fluxes and thermal structure of a tropical hydroelectric reservoir  

NASA Astrophysics Data System (ADS)

We study the influence of cold fronts on the heat fluxes and thermal structure of a tropical reservoir located in Brazil. The period chosen for this study consisted of 49 days between 28 April 2010 and 15 July 2010 and was defined based on information from the Brazilian Centre for Weather Forecasting and Climate Studies (CPTEC), data collected in situ and the interpretation of remotely sensed images. During the selected time period, five cold front passages were identified, allowing us to analyze the cumulative effect of cold fronts and the reservoir's resilience on the days that elapsed between the passages. To better understand the physical processes that drive changes in heat fluxes and thermal structure, a simulation was performed that utilized a three-dimensional hydrodynamic model. The results showed that during the cold front days, the sensible and latent heat fluxes were enhanced by approximately 24% and 19%, respectively. The daily average heat loss was up to 167% higher on the cold front days than on the non-cold front days. The high heat loss and the increased wind intensity that occurred during the cold front passages destabilized the water column and provided partial or complete mixing. The colder waters of the Paranaíba River contributed to reestablish the thermal stratification following the passages of the cold fronts. These results suggest that cold front passages play an important role in the stratification and mixing regimes of Brazilian reservoirs located in southern and southeastern regions.

Curtarelli, M. P.; Alcântara, E. H.; Rennó, C. D.; Stech, J. L.

2013-07-01

26

Orographic low-level clouds of Southeast Asia during the cold surges of the winter monsoon  

NASA Astrophysics Data System (ADS)

This study is an examination of low clouds over Southeast Asia during northern fall and winter using albedo values derived from visible images, cloud-top temperatures from infrared radiation images from the Multi-functional Transport Satellite 1 (MTSAT-1), and rainfall-top height (storm height) from precipitation radar (PR) on the Tropical Rainfall Measuring Mission (TRMM) satellites. To understand the cloud and precipitation activities associated with the winter monsoon cold surges along the eastern coast of the Indochina Peninsula, atmospheric circulation data from the Japanese 25-year reanalysis (JRA-25) were used. The results showed that low clouds were frequently observed in December, January, and February. In October and November, rainfall activity was relatively high, whereas, in northern winter, it was low, although the winter monsoon northeasterly was strong in both cases. The cloud-top height and storm height decreased with the seasonal march from northern fall to winter. Also examined in this study were the temporal variations in cloud activity on shorter time scales than those of the seasonal march. Concurrent with the cold surges along the eastern coast of the Eurasia, clouds varied on synoptic and intraseasonal time scales. The timing of low-cloud formation corresponded to the beginning of the cold surges. However, the low clouds along the eastern coast of the Indochina Peninsula may remain during the weakening phase of the cold surges.

Takahashi, Hiroshi G.

2013-09-01

27

Effects of cold front passage on turbulent fluxes over a large inland water  

NASA Astrophysics Data System (ADS)

Turbulent fluxes of sensible and latent heat over a large inland water in southern USA were measured using the eddy covariance method through the year of 2008. In addition, net radiation, air temperatures and relative humidity, and water temperature in different depths were also measured. The specific objective of this study is to examine effects of a cold front passage on the surface energy fluxes. For the typical cold front event selected from April 11 to 14, air temperature decreased by 16°C, while surface temperature only dropped 6°C. Atmospheric vapor pressure decreased by 1.6 kPa, while that in the water-air interface dropped 0.7 kPa. The behavior difference in the water-air interface was caused by the passage of cold, dry air masses immediately behind the cold front. During the cold front event, sensible heat and latent heat flux increased by 171 W m-2 and 284 W m-2, respectively. Linear aggression analysis showed that the sensible heat flux was proportional to the product of wind speed and the temperature gradient of water-air interface, with a correlation coefficient of 0.95. Latent heat flux was proportional to the product of wind speed and vapor pressure difference between the water surface and overlaying atmosphere, with a correlation coefficient of 0.81. Also, the correlations between both fluxes and the wind speed were weak. This result indicated that the strong wind associated with the cold front event contributed to the turbulent mixing, which indirectly enhanced surface energy exchange between the water surface and the atmosphere. The relationship between the water heat storage energy and turbulent fluxes was also examined.

Zhang, Q.; Liu, H.

2011-12-01

28

ALMA front-end verification using dry cold load  

NASA Astrophysics Data System (ADS)

We describe the design and characterisation of a cryogenic millimetre/sub-millimetre wave calibration load, cooled by use of a closed cycle refrigerator that is used to test the performance of the ALMA receiver front-end system. Use of the refrigerator removes the need for liquid cryogen (nitrogen) cooling and allows for long duration, and unattended operation independent of orientation angle. Key requirements of the load include provision of a well-characterised and constant brightness temperature over a wide frequency range (from ~100 GHz to ~1 THz) polarisation insensitivity, high emissivity and mechanical stability. Test and verification of the load performance characteristics is achieved by using several measurement techniques; these are presented and compared with measurements made using a liquid cryogen load (cooled reference).

Lee, Yoonjae; Ellison, Brian; Huggard, Peter; Harman, Mark; Boughriet, Abdelhakim; Bartynowski, Wojciech; Oldfield, Matthew; Morris, Nigel; Hekman, Peter; Tan, Gie Han

2010-07-01

29

United States Historians, Cold War Rhetoric, and The Finnish Winter War.  

ERIC Educational Resources Information Center

The U.S. attitude toward Finland during the Cold War years reveals much about U.S. society and politics. In particular, the war between Finland and the Soviet Union during 1939 and 1940 (Finnish Winter War) and the way in which the United States reacted to it at the time and in the years following World War II has relevance for better…

Olson, Keith W.

30

The contribution of cold winter temperatures to the 2003 alewife population collapse in Lake Huron  

USGS Publications Warehouse

The Lake Huron ecosystem has recently undergone dramatic changes. As part of those changes, the once highly abundant non-native alewife Alosa pseudoharengus population crashed in 2003 and has yet to recover. The purpose of this study was to evaluate whether temperature played a role in the population crash, because historically alewife have been subject to die-off events in response to cold temperatures in other lakes. Long-term climate data (1973–2009) showed that the winter of 2002–2003 exhibited the largest drop in degree days relative to the previous year, had the most extensive average March ice coverage, and was among the coldest years on record. However, since 2003, winter temperatures have not been overly cold, and air temperature has shown an increasing trend. Also, the relationship between temperature and alewife abundance between 1975 and 2006 was non-significant. Therefore, although we found evidence that cold winter temperatures contributed to the abrupt decline of alewife in 2003, they could not explain why the population failed to recover as it had after previous cold winters. Historically, Chinook salmon abundance contributed to long-term trends in alewife abundance, however, we found predation by Chinook to play a lesser role on the 2003 alewife collapse. In the absence of direct estimates of food availability, analyses of alewife length data suggest that a declining prey base altered the ecosystem conditions for alewife, possibly contributing to their collapse and lack of recovery.

Dunlop, Erin;Riley, Stephen

2013-01-01

31

DYNAMICS AND MAGNETIZATION IN GALAXY CLUSTER CORES TRACED BY X-RAY COLD FRONTS  

SciTech Connect

Cold fronts (CFs)-density and temperature plasma discontinuities-are ubiquitous in cool cores of galaxy clusters, where they appear as X-ray brightness edges in the intracluster medium, nearly concentric with the cluster center. We analyze the thermodynamic profiles deprojected across core CFs found in the literature. While the pressure appears continuous across these CFs, we find that all of them require significant centripetal acceleration beneath the front. This is naturally explained by a tangential, nearly sonic bulk flow just below the CF, and a tangential shear flow involving a fair fraction of the plasma beneath the front. Such shear should generate near-equipartition magnetic fields on scales {approx}<50pc from the front and could magnetize the entire core. Such fields would explain the apparent stability of cool core CFs and the recently reported CF-radio minihalo association.

Keshet, Uri; Markevitch, Maxim; Birnboim, Yuval; Loeb, Abraham [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2010-08-10

32

The climatology of East Asian winter monsoon and cold surges from 1979--1995 NCEP/NCAR reanalyses  

SciTech Connect

The East Asian winter monsoon, which is associated with the Siberian high and active cold surges, is one of the most energetic monsoon circulation systems. The dramatic shift of northeasterlies and the outbreak of cold surges dominate the winter weather and local climate in the East Asian region, and may exert a strong impact on the extratropical and tropical planetary-scale circulations and influence the SSTs in the tropical western Pacific. General characteristics of the winter monsoon and cold surges and their possible link with tropical disturbances are revealed in many observational studies. Little attention has been given to the climatological aspects of the winter monsoon and cold surges. The purpose of this study is to compile and document the East Asian mean winter circulation, and present the climatology of cold surges and the Siberian high based on the 1979--1995 NCEP/NCAR reanalyses. Of particular interest is the interannual variation of winter monsoon circulation and cold surge events. Given that the cold surge activity and the Indonesian convection are much reduced during the 1982--83 period, one of the goals is to determine whether there exists a statistically significant relationship between ENSO and the interannual variation of winter monsoon and cold surges.

Yi Zhang; Sperber, K.; Boyle, J.

1996-04-01

33

Cold temperature increases winter fruit removal rate of a bird-dispersed shrub.  

SciTech Connect

Kwit, C., D. J. Levey; C. H. Greenberg, S. F. Pearson, J.P. McCarty, and S. Sargent. Cold temperature increases winter fruit removal rate of a bird-dispersed shrub. Oecologia. 139:30-34. Abstract: We tested the hypothesis that winter removal rates of fruits of wax myrtle, Myrica cerifera, are higher in colder winters. Over a 9-year period, we monitored M. cerifera fruit crops in 13 0.1-ha study plots in South Carolina, U.S.A. Peak ripeness occurred in November, whereas peak removal occurred in the coldest months, December and January. Mean time to fruit removal within study plots was positively correlated with mean winter temperatures, thereby supporting our hypothesis. This result, combined with the generally low availability of winter arthropods, suggests that fruit abundance may play a role in determining winter survivorship and distribution of permanent resident and short-distance migrant birds. From the plant's perspective, it demonstrates inter-annual variation in the temporal component of seed dispersal, with possible consequences for post-dispersal seed and seedling ecology.

Charles Kwit; Douglas J. Levey; Cathryn H. Greenberg; Scott F. Pearson; John P. McCarty; Sarah Sargent

2004-01-10

34

Weakened cyclones, intensified anticyclones and recent extreme cold winter weather events in Eurasia  

NASA Astrophysics Data System (ADS)

Extreme cold winter weather events over Eurasia have occurred more frequently in recent years in spite of a warming global climate. To gain further insight into this regional mismatch with the global mean warming trend, we analyzed winter cyclone and anticyclone activities, and their interplay with the regional atmospheric circulation pattern characterized by the semi-permanent Siberian high. We found a persistent weakening of both cyclones and anticyclones between the 1990s and early 2000s, and a pronounced intensification of anticyclone activity afterwards. It is suggested that this intensified anticyclone activity drives the substantially strengthening and northwestward shifting/expanding Siberian high, and explains the decreased midlatitude Eurasian surface air temperature and the increased frequency of cold weather events. The weakened tropospheric midlatitude westerlies in the context of the intensified anticyclones would reduce the eastward propagation speed of Rossby waves, favoring persistence and further intensification of surface anticyclone systems.

Zhang, Xiangdong; Lu, Chuhan; Guan, Zhaoyong

2012-12-01

35

WCS120 protein family and frost tolerance during cold acclimation, deacclimation and reacclimation of winter wheat.  

PubMed

We studied how long-term cold acclimation of winter wheat (variety Mironovskaya 808), interrupted by deacclimation and then followed by reacclimation, affected the levels of cold-induced WCS120 proteins, dry-weight content, and frost tolerance in leaves. Two experiments were performed: (1) plants undergoing long-term cold acclimation (up to 112days) were quickly deacclimated (for 5days), and then reacclimated again to cold; (2) plants vernalized for varying periods of time in an early stage of their development were, after a longer deacclimation of about 14days, exposed for the same time period to cold. Five members of the WCS120 protein family were detected and quantified by image analysis in protein gel blots (in the first experiment); as well as in two-dimensional electrophoresis gels (in the second experiment). In both experiments, partially vernalized plants, after reacclimation, re-established their frost tolerance to levels similar to plants having had the same duration of cold treatment, but without deacclimation. On the other hand, these partially and fully vernalized plants reaccumulated WCS120 proteins to lower levels than plants that were not deacclimated. Further, using a mathematical model (the peak four-parameter Weibull equation), the same type of response curve was observed during plant cold treatment not only for the level of frost tolerance, but also for dry-weight content and accumulation of WCS120 proteins, with the maximum values reached at about the same time as vernalization saturation. PMID:18676155

Vítámvás, Pavel; Prásil, Ilja Tom

2008-11-01

36

Near-Surface Shear Flow in the Tropical Pacific Cold Tongue Front  

Microsoft Academic Search

Near-surface shear in the Pacific cold tongue front at 28N, 1408W was measured using a set of five moored current meters between 5 and 25 m for nine months during 2004-05. Mean near-surface currents were strongly westward and only weakly northward (; 3c m s21). Mean near-surface shear was primarily westward and, thus, oriented to the left of the southeasterly

MEGHAN F. CRONIN; WILLIAM S. KESSLER

2008-01-01

37

Heat production in cold and long scotophase acclimated and winter acclimatized rodents  

NASA Astrophysics Data System (ADS)

Heat production by means of oxygen consumptionVo2 (at Ta = 6° C, 25° C, 30° C, and 32° C) and non-shivering thermogenesis (NST) were studied in individuals of a diurnal rodent ( Rhabdomys pumilio) and a nocturnal rodent ( Praomys natalensis). The studied mice were acclimated to cold at Ta=8°C with a photoperiod of LD 12:12. On the otherhand specimens of these two species were acclimated at Ta=25°C with a long scotophase LD8:16. The results were compared with a control group (Ta=25° C, LD 12:12) and winter acclimatized individuals of both species.Vo2 in cold acclimated mice of both species was significantly increased when compared to the control group and was even higher than the winter acclimatized group when measured below the lower critical temperature. Long scotophase acclimated mice of both species also increased their oxygen consumption significantly when compared to the control group. NST was significantly increased in long scotophase acclimated mice from both species when compared to the control group. The results of this study indicate that the effects of acclimation to long scotophase are similar to those of cold acclimation. As changes in photoperiod are regular, it may be assumed that heat production mechanisms in acclimatization to winter will respond to changes in photoperiodicity.

Haim, A.; Fourie, F. Le R.

1980-09-01

38

Effects of cold winters and regime shifts on macrofauna communities in shallow coastal regions  

NASA Astrophysics Data System (ADS)

Several ecosystem components in the North Sea have undergone fundamental changes following climatic change and this paper aims to establish if these changes also have affected macrofauna communities in the southern North Sea. From 1978 to 2005, the macrofauna communities were sampled seasonally in the sublittoral zone off the island of Norderney, one of the East Frisian barrier islands. Abundance, biomass and species numbers of single species or larger taxonomic groups showed differences in long-term variability and eurytherm species dominated in the study area. After the cold winter of 1978/79 until the mid 1980s a higher percentage of arctic-boreal species were found, while after 1988 the percentage of species with a southern distribution in the North Sea increased in connection with a smooth biological regime shift and a positive North Atlantic Oscillation (NAO) index. Interface-feeders dominated the communities, followed by sand lickers and subsurface deposit-feeders. The latter were more abundant after cold winters, probably due to their ability to utilise dead buried faunal organic matter. Multivariate analyses revealed that cold winters affected the community structure more briefly, while a smooth biological regime shift in 1989/1990 and a climate regime shift induced abrupt biological regime shift in 2001/2002 caused longer-term progressive change in the macrofauna community structure. The significant correlation between macrofauna abundance, biomass and species number and the NAO index failed until 2001 due to a change in climate systems over the northern Atlantic hemisphere.

Kröncke, Ingrid; Reiss, Henning; Dippner, Joachim W.

2013-03-01

39

Relating global precipitation to atmospheric fronts  

NASA Astrophysics Data System (ADS)

Atmospheric fronts are important for the day-to-day variability of weather in the midlatitudes, particularly during winter when extratropical storm-tracks are at their maximum intensity. Fronts are often associated with heavy rain, and strongly affect the local space-time distribution of rainfall. A recently developed objective front identification method that distinguishes between cold, warm and quasi-stationary fronts, is applied to reanalysis data and combined with a daily global gridded data set to investigate how precipitation around the globe is associated with atmospheric fronts. A large proportion (up to 90%) of rainfall in the major storm-track regions is associated with fronts, particularly cold and warm fronts. Precipitation over the oceanic storm-tracks is mostly associated with cold fronts, while over the Northern Hemisphere continents precipitation is mainly associated with warm fronts. There are seasonal and regional variations in the proportion of precipitation associated with fronts.

Catto, J. L.; Jakob, C.; Berry, G.; Nicholls, N.

2012-05-01

40

Links between solar wind variations, the global electric circuit, and winter cyclone vorticity, and possibly to cold winters in Europe  

NASA Astrophysics Data System (ADS)

There are a number of inputs to the atmosphere and the climate system that are modulated by solar activity that have their only common feature the modulation of the ionosphere-earth current density (Jz) in the global electric circuit, and to which it has now been shown there are small atmospheric responses in winter storm vorticity, surface pressure, and cloud cover. Similar responses are found to internal atmospheric inputs that modulate Jz. An inductive mechanism for initial storm electrification is described that responds to Jz and provides space charge for aerosol particles and droplets throughout the updraft region. The charge on droplets and aerosol particles, by the process of charge modulation of aerosol scavenging (CMAS), increases condensation nuclei concentrations and shifts their distributions to smaller average sizes. This produces smaller and more numerous droplets, and as shown by Rosenfeld et al (2008), delays initial precipitation and increases ice production and the vigor of the storm updraft. For baroclinic storms the additional latent heat release and updraft velocity increases storm vorticity. The result depends on both aerosol characteristics and the Jz variation. The cumulative effect of winter storm intensification, for example in the Icelandic Low cyclogenesis region, responding to Jz changes, is to increase blocking in the Atlantic Ocean. Such blocking reduces the flow of relatively warm moist ocean air onto Europe, while increasing the incidence of outbreaks of cold, dry, Arctic air. The possibility is examined that increases in cosmic ray flux and in Jz, at times of decadal and longer minima in solar activity, contributes to the changes in atmospheric circulation and the resulting unusually severe winters in the UK and Europe such as have occurred during extended solar minima in the late 17th century and early 21st century.

Tinsley, B. A.

2011-12-01

41

Cold-induced bradycardia in man during sleep in Arctic winter nights  

NASA Astrophysics Data System (ADS)

Two young male Caucasians volunteered for a study on the effects of cold exposure during night sleep in winter in the Arctic. The 14-day experiment was divided in three consecutive periods, baseline (2 nights), cold exposure (10 night) and recovery (2 nights). Both baseline and recovery data were obtained in neutral thermal conditions in a laboratory. The subjects slept in a sleeping bag under an unheated tent during the cold exposure. Apart from polysomnographic and body temperature recordings, electrocardiograms were taken through a telemetric system for safety purposes. Heart rates were noted at 5-min intervals and averaged hourly. In both environmental conditions, heart rate decreased within the first two hours of sleep. Comparison of the data obtained during cold exposure vs. thermal neutrality revealed lower values of heart rate in the cold, while body temperatures remained within normal range. This cold-induced bradycardia supervening during night sleep is discussed in terms of the occurrence of a vagal reflex preventing central blood pressure to rise.

Buguet, A. G. C.

1987-03-01

42

Fine-scale observations of the structure and evolution of a tornadic cold front  

NASA Astrophysics Data System (ADS)

On 29 November 2011 a strong cold front crossed the UK. An intense, narrow rain band accompanied the front over northern England, along which several small tornadoes developed. The vertical structure of the front was sampled as it approached the UK, using dropsondes and in-situ aircraft measurements, as part of the DIAbatic influences on Mesoscale structures in ExTratropical storms (DIAMET) field campaign. One-minute-resolution data from the Met Office's network of automatic weather stations (AWSs) were used to investigate the structure of the surface front as it crossed the UK. 'Time-to-space' conversion of the AWS data, using a system motion vector estimated from sequences of radar data, permitted a fine-scale analysis of the surface frontal structure and its variation in the along-front direction. On the 28th, operational Unified Model output and aircraft dropsondes showed two separate fronts in the eastern Atlantic Ocean. By the morning of the 29th, dropsondes south of Ireland presented some features consistent with kata (also known as 'split') fronts, with two distinct, but overlapping dry intrusions, each overrunning saturated air below. Each dry intrusion was associated with a local maximum in the cross-front wind component, with a forward-directed, front-relative flow of ~ 5 - 10 m/s. Radar data showed the presence of multiple, narrow rain bands over Ireland and western extremities of the UK early on the 29th, as the front moved within range of the UK radar network. Over Ireland, the merger of at least two separate rain bands was observed. The merged band intensified and accelerated eastwards, leading to a single, intense, bowing line segment over northern England, along which the tornadoes occurred. In contrast, over southern England, no merger occurred, and the frontal zone was characterised by multiple rain bands for the duration of the observation period. The surface data showed markedly different structure in the temperature, wind and pressure fields in these two regions. Observational analyses, derived from the surface and dropsonde data, will be presented, with a particular focus on the observed differences in frontal structure over northern and southern England. Possible reasons for the differences will be discussed. A comparison with available operational model data will also be presented.

Clark, Matt; Rosenberg, Phil; Parker, Doug

2013-04-01

43

Extremely cold events and sudden air temperature drops during winter season in the Czech Republic  

NASA Astrophysics Data System (ADS)

Today a great attention is turned to analysis of extreme weather events and frequency of their occurrence under changing climate. In most cases, these studies are focused on extremely warm events in summer season. However, extremely low values of air temperature during winter can have serious impacts on many sectors as well (e.g. power engineering, transportation, industry, agriculture, human health). Therefore, in present contribution we focus on extremely and abnormally cold air temperature events in winter season in the Czech Republic. Besides the seasonal extremes of minimum air temperature determined from station data, the standardized data with removed annual cycle are used as well. Distribution of extremely cold events over the season and the temporal evolution of frequency of occurrence during the period 1961-2010 are analyzed. Furthermore, the connection of cold events with extreme sudden temperature drops is studied. The extreme air temperature events and events of extreme sudden temperature drop are assessed using the Weather Extremity Index, which evaluates the extremity (based on return periods) and spatial extent of the meteorological extreme event of interest. The generalized extreme value distribution parameters are used to estimate return periods of daily temperature values. The work has been supported by the grant P209/11/1990 funded by the Czech Science Foundation.

Crhová, Lenka; Valeriánová, Anna; Holtanová, Eva; Müller, Miloslav; Kašpar, Marek; St?íž, Martin

2014-05-01

44

Carbon dioxide variability during cold front passages and fair weather days at a forested mountaintop site  

NASA Astrophysics Data System (ADS)

This study describes temporal carbon dioxide (CO 2) changes at a new meteorological site on a mountaintop in the Virginia Blue Ridge Mountains during the first year of measurements. Continental mountaintop locations are increasingly being used for CO 2 monitoring, and investigations are needed to better understand measurements made at these locations. We focus on CO 2 mixing ratio changes on days with cold front passages and on fair weather days. Changes in CO 2 mixing ratios are largest during cold front passages outside the growing season and on clear, fair weather days in the growing season. 67% (60%) of the frontal passages during the non-growing (growing) season have larger postfrontal than prefrontal CO 2 mixing ratios. The increase in CO 2 mixing ratio around the frontal passage is short-lived and coincides with changes in CO and O 3. The CO 2 increase can therefore be used as an additional criterion to determine the timing of frontal passages at the mountaintop station. The CO 2 increase can be explained by an accumulation of trace gases along frontal boundaries. The magnitude and duration of the CO 2 increase is affected by the wind speed and direction that determine the source region of the postfrontal air. Southward-moving fronts result in the largest prolonged period of elevated CO 2, consistent with the postfrontal advection of air from the Northeastern United States where anthropogenic contributions are relatively large compared to other areas in the footprint of the mountaintop station. These anthropogenic contributions to the CO 2 changes are confirmed through concurrent CO measurements and output from NOAA's CarbonTracker model.

Lee, Temple R.; De Wekker, Stephan F. J.; Andrews, Arlyn E.; Kofler, Jonathan; Williams, Jonathan

2012-01-01

45

Cataloguing Severe Winter Cold Snaps in the Eastern and Midwestern United States for Medium-Range Predictability  

Microsoft Academic Search

Severe winter weather can be extremely disruptive to daily life and the economy. Accurate forecasts of cold outbreaks are crucial for health and safety, as well as for emergency planning by governments and the transportation and energy sectors. Short-range winter storm warnings have become much more accurate in recent years, however forecasts in the medium-range on the order of two-weeks

K. Guirguis; A. Gershunov; S. Bennett

2009-01-01

46

Investigation of dynamical processes in the polar stratospheric vortex during the unusually cold winter 2004\\/2005  

Microsoft Academic Search

The 2004\\/2005 Arctic winter was unusually cold with high potential for Polar Stratospheric Clouds formation. We use O3 and N2O assimilated fields from Aura\\/MLS in order to describe the dynamical processes inside the polar vortex during this winter. The evolution of N2O assimilated field shows that subsidence was the dominant dynamical process between early December and late January. The mixing

L. El Amraoui; N. Semane; V.-H. Peuch; M. L. Santee

2008-01-01

47

Geographic variation in Bar-headed Geese Anser indicus: Connectivity of wintering areas and breeding grounds across a broad front  

USGS Publications Warehouse

The connectivity and frequency of exchange between sub-populations of migratory birds is integral to understanding population dynamics over the entire species' range. True geese are highly philopatric and acquire lifetime mates during the winter, suggesting that the number of distinct sub-populations may be related to the number of distinct wintering areas. In the Bar-headed Goose Anser indicus, a species found exclusively in Central Asia, the connectivity between breeding and wintering areas is not well known. Their migration includes crossing a broad front of the Himalaya Cordillera, a significant barrier to migration for most birds. Many Bar-headed Geese fly to breeding areas on the Tibetan-Qinghai Plateau (TQP), the highest plateau in the world. From 2005-2008, 60 Bar-headed Geese were captured and marked with satellite transmitters in Nepal (n = 2), India (n = 6), China (n = 29), and Mongolia (n = 23) to examine their migration and distribution. Distinct differences were observed in their migration corridors and timing of movements, including an apparent leap-frog migration pattern for geese from Mongolia. Measurements of geese from Mongolia were larger than their counterparts from China, providing some evidence of morphological differences. Alteration of habitats in China, including the warming effects of climate change on glaciers increasing runoff to TQP wetlands, may be changing goose migration patterns and timing. With the exception of one individual, all geese from Qinghai Lake, China wintered in the southern TQP near Lhasa, and their increasing numbers in that region may be related to the effects of climate change and agricultural development. Thus, our findings document both morphological and geographical variation in sub-populations of Bar-headed Geese, but their resilience to environmental change may be lost if migratory short-stopping results in larger congregations restricted to a smaller number of wintering areas. ?? Wildfowl & Wetlands Trust.

Takekawa, J. Y.; Heath, S. R.; Douglas, D. C.; Perry, W. M.; Javed, S.; Newman, S. H.; Suwal, R. N.; Rahmani, A. R.; Choudhury, B. C.; Prosser, D. J.; Yan, B.; Hou, Y.; Batbayar, N.; Natsagdorj, T.; Bishop, C. M.; Butler, P. J.; Frappell, P. B.; Milsom, W. K.; Scott, G. R.; Hawkes, L. A.; Wikelski, M.

2009-01-01

48

Geographic variation in Bar-headed geese Anser indicus: connectivity of wintering and breeding grounds across a broad front.  

USGS Publications Warehouse

The connectivity and frequency of exchange between sub-populations of migratory birds is integral to understanding population dynamics over the entire species' range. True geese are highly philopatric and acquire lifetime mates during the winter, suggesting that the number of distinct sub-populations may be related to the number of distinct wintering areas. In the Bar-headed Goose Anser indicus, a species found exclusively in Central Asia, the connectivity between breeding and wintering areas is not well known. Their migration includes crossing a broad front of the Himalaya Cordillera, a significant barrier to migration for most birds. Many Bar-headed Geese fly to breeding areas on the Tibetan-Qinghai Plateau (TQP), the highest plateau in the world. From 2005-2008, 60 Bar-headed Geese were captured and marked with satellite transmitters in Nepal (n = 2), India (n = 6), China (n = 29), and Mongolia (n = 23) to examine their migration and distribution. Distinct differences were observed in their migration corridors and timing of movements, including an apparent leap-frog migration pattern for geese from Mongolia. Measurements of geese from Mongolia were larger than their counterparts from China, providing some evidence of morphological differences. Alteration of habitats in China, including the warming effects of climate change on glaciers increasing runoff to TQP wetlands, may be changing goose migration patterns and timing. With the exception of one individual, all geese from Qinghai Lake, China wintered in the southern TQP near Lhasa, and their increasing numbers in that region may be related to the effects of climate change and agricultural development. Thus, our findings document both morphological and geographical variation in sub-populations of Bar-headed Geese, but their resilience to environmental change may be lost if migratory short-stopping results in larger congregations restricted to a smaller number of wintering areas.

Takekawa, John Y.; Heath, Shane R.; Douglas, David C.; Perry, William M.; Javed, Salim; Newman, Scott H.; Suwal, Rajendra N.; Rahman, Asad R.; Choudhury, Binod C.; Prosser, Diann J.; Yan, Baoping; Hou, Yuansheng; Batbayar, Nyambayar; Natsagdorj, Tseveenmayadag; Bishop, Charles M.; Butler, Patrick J.; Frappell, Peter B.; Milsom, William K.; Scott, Graham R.; Hawkes, Lucy A.; Wikelski, Martin

2009-01-01

49

Experimental study of the cold front propagation in the plasma shut-down experiment in the J-TEXT tokamak  

NASA Astrophysics Data System (ADS)

Mitigation of major disruptions is essential in achieving fusion energy as a commercial energy source. Many tokamaks are using massive gas injection (MGI) as the disruption mitigation method since it is the most prospective potential disruption mitigation technique at present. However, mitigation efficiency by gas jet is limited by the shallow penetration of the gas jet which results in low gas mixing efficiency. In order to improve the mixture efficiency, the propagation of the cold front induced by supersonic molecular beam injection and the interaction between the cold front and the q = 2 surface have been studied in the J-TEXT tokamak.

Huang, Yanhua; Tang, Yi; Luo, Yihui; Huang, Duwei; Jin, Wei; Xiao, Jinshui; Yang, Zhoujun; Chen, Zhongyong

2014-07-01

50

Can Winter-Active Bumblebees Survive the Cold? Assessing the Cold Tolerance of Bombus terrestris audax and the Effects of Pollen Feeding  

PubMed Central

There is now considerable evidence that climate change is disrupting the phenology of key pollinator species. The recently reported UK winter activity of the bumblebee Bombus terrestris brings a novel set of thermal challenges to bumblebee workers that would typically only be exposed to summer conditions. Here we assess the ability of workers to survive acute and chronic cold stress (via lower lethal temperatures and lower lethal times at 0°C), the capacity for rapid cold hardening (RCH) and the influence of diet (pollen versus nectar consumption) on supercooling points (SCP). Comparisons are made with chronic cold stress indices and SCPs in queen bumblebees. Results showed worker bees were able to survive acute temperatures likely to be experienced in a mild winter, with queens significantly more tolerant to chronic cold temperature stress. The first evidence of RCH in any Hymenoptera is shown. In addition, dietary manipulation indicated the consumption of pollen significantly increased SCP temperature. These results are discussed in the light of winter active bumblebees and climate change.

Owen, Emily L.; Bale, Jeffrey S.; Hayward, Scott A. L.

2013-01-01

51

VHF radar observations of gravity-wave production by cold fronts over southern Australia  

SciTech Connect

Four extended observational campaigns were conducted during August and November 1988 with an ST (stratosphere-troposphere) radar in southern Australia during the passage of cold fronts over the system, giving around 30 days of three-dimensional wind measurements with 15-min time and 0.5-km height resolution over the 2-11.5-km height range. Order of magnitude increases in the variance of time-fluctuating wind velocities were measured during frontal passages, which are ascribed to gravity waves. The time-height morphology of the horizontal and vertical velocity fluctuations differed. Bursts of horizontal velocity variance arose at upper levels about a day before the frontal boundary arrived; this activity extended to lower heights as the front neared. The arrival of the frontal boundary marked a sudden reduction in this activity. After the frontal boundary passed, reduced activity persisted for 12 hours, after which bursts returned at upper levels and persisted typically for about a day. Analysis associates this activity with a spectrum of many saturating inertia-gravity waves with long horizontal wavelengths and large ground-based phase speeds. Bursts in vertical-velocity fluctuations, w[prime], were confined to the troposphere and were quasi-sinusoidal in appearance. These fluctuations are ascribed to gravity waves with high intrinsic frequencies. Significant w[prime] amplitudes were evident after and prior to frontal passage. The largest amplitudes occurred with the onset of strong vertical circulation when the frontal boundary arrived. The smaller w[prime] amplitudes observed in the stratosphere are due in part to the more oblique propagation of wave energy in this more stable environment. Two clear cases of ducted w[prime] oscillations are identified with the aid of radiosonde temperature data from a nearby site. Comparisons between these measurements and the limited numerical modeling of frontal gravity waves show some similarities in wave characteristics.

Eckermann, S.D. (Oxford Univ., Oxfordshire (United Kingdom)); Vincent, R.A. (Univ. of Adelaide (Australia))

1993-03-15

52

MAGNETOHYDRODYNAMIC SIMULATIONS OF THE FORMATION OF COLD FRONTS IN CLUSTERS OF GALAXIES: EFFECTS OF ANISOTROPIC VISCOSITY  

SciTech Connect

We carried out three-dimensional magnetohydrodynamic simulations to study the effects of plasma viscosity on the formation of sharp discontinuities of density and temperature distributions, cold fronts, in clusters of galaxies. By fixing the gravitational potential that confines the cool, dense plasma in a moving subcluster, we simulated its interaction with the hot, lower density plasma around the subcluster. At the initial state, the intracluster medium (ICM) is assumed to be threaded by uniform magnetic fields. The enhancement of plasma viscosity along the direction of magnetic fields is incorporated as anisotropic viscosity depending on the direction of magnetic fields. We found that the Kelvin-Helmholtz instability at the surface of the subcluster grows even in models with anisotropic viscosity, because its effects on the velocity shear across the magnetic field lines are suppressed. We also found that magnetic fields around the interface between the subcluster and ICM are amplified even in the presence of viscosity, while magnetic fields behind the subcluster are amplified up to {beta}{sup -1} {approx} 0.01 in models with viscosity, whereas they are amplified up to {beta}{sup -1} {approx} 0.1 in models without viscosity, where {beta} is the ratio of gas pressure to magnetic pressure.

Suzuki, Kentaro; Ogawa, Takayuki; Matsumoto, Yosuke; Matsumoto, Ryoji, E-mail: suzukikn@astro.s.chiba-u.ac.jp, E-mail: ogawa@astro.s.chiba-u.ac.jp, E-mail: ymatumot@astro.s.chiba-u.ac.jp, E-mail: matumoto@astro.s.chiba-u.ac.jp [Department of Physics, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan)

2013-05-10

53

Characteristics of gusty wind disturbances and turbulent fluctuations in windy atmospheric boundary layer behind cold fronts  

NASA Astrophysics Data System (ADS)

Statistical analysis of turbulent and gusty characteristics in the atmospheric boundary layer with strong mean wind behind cold fronts has been carried out. The data used in the analysis were the multilevel ultrasonic anemometer-thermometer observations for 5 years during spring in East Asia. The results show: (1) there is systematical descending component of the basic flow in the lower part and ascending component in the upper part of the boundary layer; (2) the turbulent fluctuations (period less than 1 min) are nearly random and isotropic with weak coherency, but the gusty wind disturbances (1 min < period < 10 min) are anisotropic with rather strong coherency; (3) the kinetic energy of gusty wind disturbances and the related downward flux of momentum reach their maximum at some level below h*, where h* is the level separating the descending and ascending components of the mean flow; and (4) the turbulent kinetic energy and related downward flux of momentum increase first in the lowest layer and then decrease with height, if the fastest sampling frequency is 10 Hz, although the reason is unclear yet.

Cheng, Xueling; Zeng, Qing-Cun; Hu, Fei

2011-03-01

54

Magnetohydrodynamic Simulations of the Formation of Cold Fronts in Clusters of Galaxies: Effects of Anisotropic Viscosity  

NASA Astrophysics Data System (ADS)

We carried out three-dimensional magnetohydrodynamic simulations to study the effects of plasma viscosity on the formation of sharp discontinuities of density and temperature distributions, cold fronts, in clusters of galaxies. By fixing the gravitational potential that confines the cool, dense plasma in a moving subcluster, we simulated its interaction with the hot, lower density plasma around the subcluster. At the initial state, the intracluster medium (ICM) is assumed to be threaded by uniform magnetic fields. The enhancement of plasma viscosity along the direction of magnetic fields is incorporated as anisotropic viscosity depending on the direction of magnetic fields. We found that the Kelvin-Helmholtz instability at the surface of the subcluster grows even in models with anisotropic viscosity, because its effects on the velocity shear across the magnetic field lines are suppressed. We also found that magnetic fields around the interface between the subcluster and ICM are amplified even in the presence of viscosity, while magnetic fields behind the subcluster are amplified up to ?-1 ~ 0.01 in models with viscosity, whereas they are amplified up to ?-1 ~ 0.1 in models without viscosity, where ? is the ratio of gas pressure to magnetic pressure.

Suzuki, Kentaro; Ogawa, Takayuki; Matsumoto, Yosuke; Matsumoto, Ryoji

2013-05-01

55

The relationship of winter season North Atlantic blocking frequencies to extreme cold or dry spells in the ERA-40  

NASA Astrophysics Data System (ADS)

Atmospheric blocking is an important source of low-frequency variability. We apply a blocking detection and tracking method to ERA-40 data for the Atlantic-European region to assess linkages to extreme events, that is, cold and dry spells in the extended winter season (November-April). The method is feature-oriented, identifies 500-hPa geopotential height maxima, and connects them with a next-neighbourhood search in time. The analysis reveals a statistically significant decrease of number of blocking events over the period of ERA-40. Winters with an increased number of blocking events are associated with negative temperature anomalies over Central to Eastern Europe and dryer conditions, whereas Southern Europe experiences warmer and wetter conditions during such episodes. Using extreme value statistics we show evidence that cold spells, and to some extent dry spells, are strongly associated with extremes in blocking frequency. The number of cold spell days increases with the duration of blocking events indicating that cold spells need time to establish during blocking events, thus return periods of cold spells are longer than those for blocking events. This behaviour is not found for the relation of dry spells with blocking events. Still, blocking episodes have a higher occurrence of dry spells than climatology.

Buehler, Tania; Raible, Christoph C.; Stocker, Thomas F.

2011-03-01

56

The relationship of winter season North Atlantic blocking frequencies to extreme cold or dry spells in the ERA-40  

NASA Astrophysics Data System (ADS)

Atmospheric blocking is an important source of low-frequency variability. We apply a blocking detection and tracking method to ERA-40 data for the Atlantic-European region to assess linkages to extreme events, that is, cold and dry spells in the extended winter season (November-April). The method is feature-oriented, identifies 500-hPa geopotential height maxima, and connects them with a next-neighbourhood search in time. The analysis reveals a statistically significant decrease of number of blocking events over the period of ERA-40. Winters with an increased number of blocking events are associated with negative temperature anomalies over Central to Eastern Europe and dryer conditions, whereas Southern Europe experiences warmer and wetter conditions during such episodes. Using extreme value statistics we show evidence that cold spells, and to some extent dry spells, are strongly associated with extremes in blocking frequency. The number of cold spell days increases with the duration of blocking events indicating that cold spells need time to establish during blocking events, thus return periods of cold spells are longer than those for blocking events. This behaviour is not found for the relation of dry spells with blocking events. Still, blocking episodes have a higher occurrence of dry spells than climatology.

Buehler, Tania; Raible, Christoph C.; Stocker, Thomas F.

2010-11-01

57

A cold inducible multidomain cystatin from winter wheat inhibits growth of the snow mold fungus, Microdochium nivale  

Microsoft Academic Search

A novel cold-induced cystatin cDNA clone (TaMDC1) was isolated from cold acclimated winter wheat crown tissue by using a macroarray-based differential screening method. The deduced amino acid sequence consisted of a putative N-terminal secretory signal peptide of 37 amino acids and a mature protein (mTaMDC1) with a molecular mass of 23 kDa. The mTaMDC1 had a highly conserved N-terminal cystatin domain

Petya Koeva Christova; Nikolai Kirilov Christov; Ryozo Imai

2006-01-01

58

Cold, Northern Winters: The Importance of Temperature to Overwinter Mortality of Age0 White Crappies  

Microsoft Academic Search

Survival during the first winter of life can influence the recruitment of many fishes. We used field sampling and laboratory experiments to explore the mechanisms underlying first winter growth and survival of white crappie Pomoxis annularis, which exhibits variable recruitment. We sampled age-0 white crappies from four Ohio reservoirs before winter to evaluate whether large individuals had a greater energy

Arthur B. McCollum; David B. Bunnell; Roy A. Stein

2003-01-01

59

Requirement of a CCGAC cis-acting element for cold induction of the BN115 gene from winter Brassica napus  

Microsoft Academic Search

Mutation of the core pentamer, CCGAC, of two putative low temperature responsive elements (LTREs) in the 5'-proximal region of the winter Brassica napus cold-induced gene BN115 was carried out. Analyses of transient expression of the resultant mutated BN115 promoter-GUS fusions revealed the loss of low-temperature regulation by the promoter. This indicates that the CCGAC sequence is critical to the low-temperature

Chao Jiang; Betty Iu; Jas Singh

1996-01-01

60

Sloshing Cold Fronts in Galaxy Groups and their Perturbing Disk Galaxies: An X-Ray, Optical, and Radio Case Study  

NASA Astrophysics Data System (ADS)

We present a combined X-ray, optical, and radio analysis of the galaxy group IC 1860 using the currently available Chandra and XMM data, multi-object spectroscopy data from the literature, and Giant Metrewave Radio Telescope (GMRT) data. The Chandra and XMM imaging and spectroscopy reveal two surface brightness discontinuities at 45 and 76 kpc shown to be consistent with a pair of cold fronts. These features are interpreted as due to sloshing of the central gas induced by an off-axis minor merger with a perturber. This scenario is further supported by the presence of a peculiar velocity of the central galaxy IC 1860 and the identification of a possible perturber in the optically disturbed spiral galaxy IC 1859. The identification of the perturber is consistent with the comparison with numerical simulations of sloshing. The GMRT observation at 325 MHz shows faint, extended radio emission contained within the inner cold front, as seen in some galaxy clusters hosting diffuse radio mini-halos. However, unlike mini-halos, no particle reacceleration is needed to explain the extended radio emission, which is consistent with aged radio plasma redistributed by the sloshing. There is a strong analogy between the X-ray and optical phenomenology of the IC 1860 group and that of two other groups, NGC 5044 and NGC 5846, showing cold fronts. The evidence presented in this paper is among the strongest supporting the currently favored model of cold-front formation in relaxed objects and establishes the group scale as a chief environment for studying this phenomenon.

Gastaldello, Fabio; Di Gesu, Laura; Ghizzardi, Simona; Giacintucci, Simona; Girardi, Marisa; Roediger, Elke; Rossetti, Mariachiara; Brighenti, Fabrizio; Buote, David A.; Eckert, Dominique; Ettori, Stefano; Humphrey, Philip J.; Mathews, William G.

2013-06-01

61

Evolution of cold-tolerant fungal symbionts permits winter fungiculture by leafcutter ants at the northern frontier of a tropical ant-fungus symbiosis  

PubMed Central

The obligate mutualism between leafcutter ants and their Attamyces fungi originated 8 to 12 million years ago in the tropics, but extends today also into temperate regions in South and North America. The northernmost leafcutter ant Atta texana sustains fungiculture during winter temperatures that would harm the cold-sensitive Attamyces cultivars of tropical leafcutter ants. Cold-tolerance of Attamyces cultivars increases with winter harshness along a south-to-north temperature gradient across the range of A. texana, indicating selection for cold-tolerant Attamyces variants along the temperature cline. Ecological niche modeling corroborates winter temperature as a key range-limiting factor impeding northward expansion of A. texana. The northernmost A. texana populations are able to sustain fungiculture throughout winter because of their cold-adapted fungi and because of seasonal, vertical garden relocation (maintaining gardens deep in the ground in winter to protect them from extreme cold, then moving gardens to warmer, shallow depths in spring). Although the origin of leafcutter fungiculture was an evolutionary breakthrough that revolutionized the food niche of tropical fungus-growing ants, the original adaptations of this host-microbe symbiosis to tropical temperatures and the dependence on cold-sensitive fungal symbionts eventually constrained expansion into temperate habitats. Evolution of cold-tolerant fungi within the symbiosis relaxed constraints on winter fungiculture at the northern frontier of the leafcutter ant distribution, thereby expanding the ecological niche of an obligate host–microbe symbiosis.

Mueller, Ulrich G.; Mikheyev, Alexander S.; Hong, Eunki; Sen, Ruchira; Warren, Dan L.; Solomon, Scott E.; Ishak, Heather D.; Cooper, Mike; Miller, Jessica L.; Shaffer, Kimberly A.; Juenger, Thomas E.

2011-01-01

62

Central American Cold Surge: An Observational Analysis of the Deep Southward Penetration of North American Cold Fronts.  

National Technical Information Service (NTIS)

The occurrence and structure of the Central American Cold Surge (CACS) is quantified using surface and upper air observations, GOES satellite imagery and satellite estimates of total precipitable water (TPW) and rain rate. A quantitative CACS definition, ...

P. J. Reding

1992-01-01

63

Are Pectins Involved in Cold Acclimation and De-acclimation of Winter Oil-seed Rape Plants?  

PubMed Central

Background and Aims The hypothesis was tested that pectin content and methylation degree participate in regulation of cell wall mechanical properties and in this way may affect tissue growth and freezing resistance over the course of plant cold acclimation and de-acclimation. Methods Experiments were carried on the leaves of two double-haploid lines of winter oil-seed rape (Brassica napus subsp. oleifera), differing in winter survival and resistance to blackleg fungus (Leptosphaeria maculans). Key Results Plant acclimation in the cold (2 °C) brought about retardation of leaf expansion, concomitant with development of freezing resistance. These effects were associated with the increases in leaf tensile stiffness, cell wall and pectin contents, pectin methylesterase (EC 3·1·1·11) activity and the low-methylated pectin content, independently of the genotype studied. However, the cold-induced modifications in the cell wall properties were more pronounced in the leaves of the more pathogen-resistant genotype. De-acclimation promoted leaf expansion and reversed most of the cold-induced effects, with the exception of pectin methylesterase activity. Conclusions The results show that the temperature-dependent modifications in pectin content and their methyl esterification degree correlate with changes in tensile strength of a leaf tissue, and in this way affect leaf expansion ability and its resistance to freezing and to fungus pathogens.

Solecka, Danuta; Zebrowski, Jacek; Kacperska, Alina

2008-01-01

64

2009/2010 Eurasian Cold Winter and Loss of Arctic Sea-ice over Barents/Kara Sea  

NASA Astrophysics Data System (ADS)

In 2009/2010 winter, a few extreme cold events and heavy snowfall occurred over central North America, north western Europe, and East Asia exerting a severe social and economic impacts. In this study, we performed modeling experiments to examine the role of substantially reduced Arctic sea-ice over Barents/Kara Sea on the 2009/2010 cold winters. Although several previous studies investigated cause of the extreme events and emphasized the large snow-covered area over Siberia in autumn 2009, we note that the area extent of Arctic sea-ice over Barents/Kara sea in autumn 2009 was anomalously low and the possible impact from Arctic for the extreme cold events has not been presented. To investigate the influence from the Arctic, we designed three model runs using Community Atmosphere Model Version 3 (CAM3). Each simulation differs by the prescribed surface boundary conditions: (a) CTRL - climatological seasonal cycle of sea surface temperature (SST) and sea-ice concentration (SIC) are prescribed everywhere, (b) EXP_65N - SST and SIC inside the Arctic circle (north of 65°N) are replaced by 2009/2010 values. Elsewhere, the climatology is used, (c) EXP_BK - Same with (b) except that SIC and SST are fixed only over Barents/Kara Sea where the sea-ice area dropped significantly in 2009/2010 winter. Model results from EXP_65N and EXP_BK commonly showed a large increase of air temperature in the lower troposphere where Arctic sea-ice showed a large reduction. Also, compared with the observation, model successfully captured thickened geopotential height in the Arctic and showed downstream wave propagation toward midlatitude. From the analysis, we reveal that this large dipolar Arctic-midlatitude teleconnection pattern in the upper troposphere easily propagate upward and played a role in the weakening of polar vortex. This is also confirmed in the observation. However, the timing of excitation of upward propagating wave in EXP_65N and EXP_BK were different and thus the timing of weakening of polar vortex also differs in each experiment. Unlike with our expectation, both EXP_65N and EXP_BK did not capture the abrupt increase of snow-cover in the observation over Siberian region in autumn 2009. Therefore, given the successful reproduction of key observed features of cold winter 2009/2010 by EXP_65N and EXP_BK, we conclude that Arctic sea-ice in autumn 2009 played a key role for the subsequent development of cold winter 2009/2010 and the role was largely independent with the autumn snow-cover.

Shim, T.; Kim, B.; Kim, S.

2012-12-01

65

Changes in gene expression during dehardening of cold-hardened winter rye ( Secale cereale L.) leaves and potential role of a peptide methionine sulfoxide reductase in cold-acclimation  

Microsoft Academic Search

Suppression subtractive hybridization and differential display polymerase chain reactions were used to identify genes that were differentially expressed in cold-hardened and dehardened leaves of winter rye (Secale cereale L.). The transcripts of nine genes declined during dehardening at 22°C of cold-hardened 4°C-grown leaves, indicating some role in cold-acclimation. Among the genes that were strongly expressed in cold-hardened leaves were five

Oliver In; Thomas Berberich; Skander Romdhane; Jürgen Feierabend

2005-01-01

66

Fronts and orography  

Microsoft Academic Search

Summary Theoretical work on the impact of orography on cold fronts is reviewed and related to observations. This paper contains the following sections:1.Introduction2.Passive scalar fronts3.Shallow water fronts4.Fronts in deformation flows5.Orographic jets6.Cold-air damming7.Föhn and fronts8.Fronts in valleys9.Cold surges10.Lee cyclogenesis11.Orographic rain and fronts12.Pressure drag13.Numerical simulations14.Analysis

J. Egger; K. P. Hoinka

1992-01-01

67

Structural Changes in Thylakoid Proteins during Cold Acclimation and Freezing of Winter Rye (Secale cereale L. cv. Puma) 1  

PubMed Central

Thylakoids were isolated from nonhardened and cold-hardened winter rye (Secale cereale L. cv. Puma), and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence and absence of sulfhydryl reagents. Electrophoresis of cold-hardened rye thylakoid proteins revealed the presence of a 35 kilodalton polypeptide and the absence of a 51 kilodalton polypeptide found in nonhardened rye thylakoid proteins. The 35 kilodalton band could be induced by adding ?-mercaptoethanol to nonhardened rye thylakoid proteins, whereas the 51 kilodalton band could be formed by adding cupric phenanthroline to these same proteins. Sulfhydryl group titration showed that cold-hardened rye thylakoid proteins contained more free sulfhydryls than nonhardened rye proteins. Although amino acid analysis of thylakoid proteins revealed quantitative differences in several amino acid residues, the polarity of thylakoid proteins did not change during cold acclimation. No significant changes in sodium dodecyl sulfate-polyacrylamide gels of thylakoid proteins appeared when either nonhardened or cold-hardened plants were frozen in vivo or in vitro. However, thylakoid proteins did aggregate when frozen in the presence of ?-mercaptoethanol. Although thylakoid proteins isolated from cold-hardened rye contained more reduced thiols, a general state of reduction did not act as a cryoprotectant. It is hypothesized that conformational changes of specific proteins may be important for low temperature growth of rye. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Griffith, Marilyn; Brown, Gregory N.; Huner, Norman P. A.

1982-01-01

68

Extreme temperature contrast of the year 2012 in Greece: An exceptionally cold winter and a record breaking summer  

NASA Astrophysics Data System (ADS)

During the past decade several regions all over Europe have experienced severe heat waves with serious social and environmental impacts. The year of 2003 was characterized by record breaking high temperatures for central Europe, while the year of 2007 was a remarkably warm year of the majority of the Eastern Mediterranean. During this year, three major heat waves were detected in Greece during summer and abnormally high temperatures were also observed through the cold season of 2007. It was found that the winter minimum temperatures were statistically more extreme than the summer maxima. Moreover, exceptionally high maximum and minimum temperatures occurred in November of 2010 affection the entire Greek region while September of the following year was also characterized by large departures of maximum temperatures from the long term mean values and the highest minimum temperature average in comparison to the reference period 1958-2000. The past year (2012) could also be characterized as a year of extremes. This time a temperature contrast was detected in the domain of study with a prolonged cold - season spell during winter and new record - breaking extreme maximum and minimum summer temperatures. More specifically it was found that the summer of 2012 was the warmest one since 1958. The whole season was characterized by long - lasting warm conditions with large departures from the long term (up to 4oC for Tmax) and this warming phenomenon was more intense during July and August. In contrast the winter season (December 2011 - February 2012) was found to be in the ten coldest winters of the last 55 years. The departures from the mean are lower than summer (1oC to 1.5oC negative anomalies) but most of the days were found to have lower Tmax, Tmin and Tmean values than the average daily temperatures of the period 1958-2000. Finally, it is worth mentioning that the year of 2012 was characterized by the highest annual temperature range reaching up to 26oC in several stations. Consequently, these abnormal cold (warm) conditions during the winter (summer) months motivated the present study in order to conduct a statistical analysis of these temperature extremes and their characteristics in addition to an investigation of the synoptic large scale atmospheric conditions which possibly result to this year of contrasts. Acknowledgments: This study has been supported by the Research Committee of the Aristotle University of Thessaloniki.

Tolika, Konstantia; Anagnostopoulou, Christina; Maheras, Panagiotis; Velikou, Kondylia

2013-04-01

69

The relation of extreme North Atlantic blocking frequencies, cold and dry spells in ERA-40 in winter  

NASA Astrophysics Data System (ADS)

One of the most prominent features of mid-latitude atmospheric variability is blocking. Blocking events are anticyclones with an equivalent barotropic signature and persistent in time. The longer than synoptic day-to-day time scales has led to intrinsic interest during the last decades aiming to expand the predictability beyond classical numerical weather prediction. The study aims to present the extreme behavior of blocking and to investigate relations to other extreme events, like cold and dry spells. To assess the behavior of blocking events we developed a new event-based method. The method identifies 500-hPa geopotential height maxima and tracks these relative maxima with a next-neighborhood search in time. This new method agrees with the reference grid-point based method in the deduced climatological pattern of blocking frequency. Applying the method to ERA-40 data in winter for the Atlantic-European region we found a trend towards a reduction of blocking episodes. The mean surface temperature and precipitation shows a clear response: winters with an increased number of blocking events are associated with negative temperature anomalies over central to eastern Europe and dryer conditions, whereas southern Europe experiences warmer and wetter conditions during such episodes. Using extreme value statistics, we show evidence that cold spells and to some extent dry spells are strongly associated with extremes in blocking frequency over central Europe. We also showed that cold spells need time to establish during blocking events, thus return periods of cold spells are longer than those for blocking events.

Raible, C. C.; Buehler, T.; Stocker, T. F.

2009-04-01

70

Investigation of dynamical processes in the polar stratospheric vortex during the unusually cold winter 2004/2005  

NASA Astrophysics Data System (ADS)

The 2004/2005 Arctic winter was unusually cold with high potential for Polar Stratospheric Clouds formation. We use O3 and N2O assimilated fields from Aura/MLS in order to describe the dynamical processes inside the polar vortex during this winter. The evolution of N2O assimilated field shows that subsidence was the dominant dynamical process between early December and late January. The mixing effect between the polar vortex and midlatitudes has been diagnosed using the effective diffusivity parameter. It shows that from early February to the end of March, mixing was dominant compared to diabatic descent. The vortex-averaged ozone loss profile from O3 assimilated field shows a maximum of ~1.5 ppmv at 425 K, which is less pronounced compared to other winters of similar meteorological conditions (e.g., 1999/2000). This is due to the importance of the mixing processes between the polar vortex and midlatitudes which bring in ozone-rich air to the vortex.

El Amraoui, L.; Semane, N.; Peuch, V.-H.; Santee, M. L.

2008-02-01

71

Cold core eddies and fronts of the Antarctic Circumpolar Current south of New Zealand from in situ and satellite data  

NASA Astrophysics Data System (ADS)

The meridional heat flux required to balance the heat lost by ocean to atmosphere at high latitudes must be accomplished by some mechanism other than mean advection and the heat flux by eddies crossing the Antarctic Circumpolar Current (ACC) may be a candidate. In this study, the positions of the main ACC fronts are determined based on 23 expendable bathythermographs (XBT) transects collected from 1994 to 2010 and are compared with those detected through satellite altimetry. Then, cold core anomalies in XBT sections are identified and altimetry is used to follow the spatial-temporal evolution of these cold, low sea level anomalies. Mean values of main parameters, such as speed (0.35 km/h), lifetime (79 weeks), and diameter (105 km), are estimated. Moreover, estimations of rotational speed (0.9-76.8 cm/s), ocean surface layer heat content along temperature sections and eddy available heat anomaly (mean value -9.74 × 109 Jm-2) give a wider description of the detected eddies. In our study area, the spawning of eddies is found to occur downstream of the Southeast Indian Ridge and in correspondence of the polar front (PF) with regard to the ACC frontal structure. The contribution of eddies to the global heat budget is not only linked to their ability to cross the ACC fronts but also to the capacity of keeping partially unaltered the properties of water inside them. Analysis of the relation between the translation and rotational speeds shows that a typical eddy may effectively be a significant part (0.8%) of the net meridional heat transport across the PF with a mean heat content/anomaly of -7.65 × 1019 J.

Cotroneo, Yuri; Budillon, Giorgio; Fusco, Giannetta; Spezie, Giancarlo

2013-05-01

72

Comparison of subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers in Japan.  

PubMed

To help making comfortable workplaces and to prevent health disorders induced by the exposure to moderate cold in two different groups of out-door workers, we conducted a survey to compare subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers. The subjects of this study were 98 male traffic control workers and 149 male workers engaged in building construction. Work loads of traffic control workers and construction workers were estimated at RMR1-2 and RMR2-4, respectively. All subjects were asked to complete a self-administered questionnaire covering age, occupational career, working figure, present illness, past history of diseases, individual preventive measures to the cold, subjective symptoms in the winter (43 items) and subjective symptoms occurred during daytime working in the winter (6 items). In two parts of the construction workplaces (the place where a morning assembly was held and on the 7th floor of the construction site) dry bulb, wet bulb and globe temperatures were measured in January. Windchill Index (kcal/cm,(2) x h) was calculated by the measured dry bulb temperature and wind velocity. Mean values of dry bulb temperature between 9:00 and 16:30 in the place where a morning assembly was held for three days were between 4.8 +/- 1.2 degrees C at 9:00 am and 9.3 +/- 1.1 degrees C at noon. Mean values of Windchill Index in the place where a morning assembly was held were between 490.8+/-23.9 kcal/cm(2) x h at 9:30 am and 608.2+/-47.3 kcal/cm(2) x h at 2:30 pm. Occupational career, monthly working days, daily working hours, one way commuting hours, and daily smoking numbers of the traffic control workers were significantly shorter than the construction workers (p<0.01). There were no significant differences in the prevalence of chillness in the arms and legs between the traffic control workers (5.1%) and the construction workers (0.7%). Prevalence of wearing a warm underwear, body warmer, warm trousers, underpants, warm socks, shoe warmer and muffler in the traffic control workers were significantly higher than the construction workers. The subjective symptoms in winter complained most frequently were shoulder stiffness (51.0%), finger cold sensation (50.0%) and neck stiffness (48.0%) in the traffic control workers, and were easy to get fatigued (49.0%), lumbago (48.3%) and finger cold sensation (47.7%) in the construction workers. On the basis of the results obtained, it is clearly shown that the two groups are at the risk of disorders due to their working environment. Therefore, these workers are needed to undergo occupational health programs for prevention of cold exposure disorders. Applications of preventive countermeasures for both groups are discussed. PMID:19531914

Inaba, Ryoichi; Kurokawa, Junichi; Mirbod, Seyed Mohammad

2009-07-01

73

Lower Stratospheric Temperature Differences Between Meteorological Analyses in two cold Arctic Winters and their Impact on Polar Processing Studies  

NASA Technical Reports Server (NTRS)

A quantitative intercomparison of six meteorological analyses is presented for the cold 1999-2000 and 1995-1996 Arctic winters. The impacts of using different analyzed temperatures in calculations of polar stratospheric cloud (PSC) formation potential, and of different winds in idealized trajectory-based temperature histories, are substantial. The area with temperatures below a PSC formation threshold commonly varies by approximately 25% among the analyses, with differences of over 50% at some times/locations. Freie University at Berlin analyses are often colder than others at T is less than or approximately 205 K. Biases between analyses vary from year to year; in January 2000. U.K. Met Office analyses were coldest and National Centers for Environmental Prediction (NCEP) analyses warmest. while NCEP analyses were usually coldest in 1995-1996 and Met Office or NCEP[National Center for Atmospheric Research Reanalysis (REAN) warmest. European Centre for Medium Range Weather Forecasting (ECMWF) temperatures agreed better with other analyses in 1999-2000, after improvements in the assimilation model. than in 1995-1996. Case-studies of temperature histories show substantial differences using Met Office, NCEP, REAN and NASA Data Assimilation Office (DAO) analyses. In January 2000 (when a large cold region was centered in the polar vortex), qualitatively similar results were obtained for all analyses. However, in February 2000 (a much warmer period) and in January and February 1996 (comparably cold to January 2000 but with large cold regions near the polar vortex edge), distributions of "potential PSC lifetimes" and total time spent below a PSC formation threshold varied significantly among the analyses. Largest peaks in "PSC lifetime" distributions in January 2000 were at 4-6 and 11-14 days. while in the 1996 periods, they were at 1-3 days. Thus different meteorological conditions in comparably cold winters had a large impact on expectations for PSC formation and on the discrepancies between different meteorological analyses. Met Office. NCEP, REAN, ECMWF and DAO analyses are commonly used for trajectory calculations and in chemical transport models; the choice of which analysis to use can strongly influence the results of such studies.

Manney, Gloria L.; Sabutis, Joseph L.; Pawson, Steven; Santee, Michelle L.; Naujokat, Barbara; Swinbank, Richard; Gelman, Melvyn E.; Ebisuzaki, Wesley; Atlas, Robert (Technical Monitor)

2001-01-01

74

Primary and secondary metabolism of winter wheat under cold hardening and treatment with antioxidants  

Microsoft Academic Search

The content of saccharides and phenolic compounds (including flavonoids and lignin) and the activity of L-phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were determined in leaves and tillering nodes of winter wheat Triticum aestivum L.) cultivars Inna and Moskovskaya 39, differing in the level of frost resistance. These parameters were determined in three\\u000a groups of plants—control, hardened, and treated with synthetic antioxidants

N. A. Olenichenko; N. V. Zagoskina; N. V. Astakhova; T. I. Trunova; Yu. V. Kuznetsov

2008-01-01

75

Effect of light on the gene expression and hormonal status of winter and spring wheat plants during cold hardening.  

PubMed

The effect of light on gene expression and hormonal status during the development of freezing tolerance was studied in winter wheat (Triticum aestivum var. Mv Emese) and in the spring wheat variety Nadro. Ten-day-old plants (3-leaf stage) were cold hardened at 5°C for 12 days under either normal (250 µmol m(-2) s(-1) ) or low (20 µmol m(-2) s(-1) ) light conditions. Comprehensive analysis was carried out to explore the background of frost tolerance and the differences between these wheat varieties. Global genome analysis was performed, enquiring about the details of the cold signaling pathways. The expression level of a large number of genes is affected by light, and this effect may differ in different wheat genotypes. Photosynthesis-related processes probably play a key role in the enhancement of freezing tolerance; however, there are several other genes whose induction is light-dependent, so either there is cross-talk between signaling of chloroplast originating and other protective mechanisms or there are other light sensors that transduce signals to the components responsible for stress tolerance. Changes in the level of both plant hormones (indole-3-acetic acid, cytokinins, nitric oxide and ethylene precursor 1-aminocyclopropane-1-carboxylic acid) and other stress-related protective substances (proline, phenolics) were investigated during the phases of the hardening period. Hormonal levels were also affected by light and their dynamics indicate that wheat plants try to keep growing during the cold-hardening period. The data from this experiment may provide a new insight into the cross talk between cold and light signaling in wheat. PMID:22257084

Majláth, Imre; Szalai, Gabriella; Soós, Vilmos; Sebestyén, Endre; Balázs, Ervin; Vanková, Radomíra; Dobrev, Petre I; Tari, Irma; Tandori, Júlia; Janda, Tibor

2012-06-01

76

Synoptic climatological study on precipitation in the Hokuriku District of Central Japan associated with the cold air outbreak in early winter (With Comparison to that in midwinter for the 1983/1984 winter)  

NASA Astrophysics Data System (ADS)

In midwinter, heavy snowfall events are often brought in the Japan Sea side of the Japan Islands by the organized convective snowfall systems in the cold air outbreak situations. However, although the air temperature around the Japan Islands is still rather higher from November to early December ("early winter"), the "wintertime pressure pattern" often appears due to the considerable development of the Siberian high already in that season. Since the seasonal cycle in East Asia shows great variety with many rapid seasonal transitions influenced by the Asian monsoon system, detailed comparison of the daily precipitation climatology and the relating atmospheric processes in the cold air outbreak situations between early winter and midwinter would give us an interesting information for comprehending the overall aspects of such seasonal cycle there. Thus the present study firstly examined the daily precipitation climatology mainly at Takada, as an example for Hokuriku District, during the early to mid- winter of 1970/71 to 2009/10. Then the detailed analyses were made for the 1983/1984 winter (one of the coldest winters during that period) based on the operational meteorological data by JMA, including the ocean buoy data in the southern part of the Japan Sea for evaluating the sensible and the latent heat fluxes from the sea (referred to as SH and LH, respectively). The total precipitation at Takada in early winter was as large as in midwinter, although it was brought mainly not as snow but as rain. Such large climatological value was mainly reflected by the precipitation in the "wintertime pressure pattern" with large contribution of the days with more than 30 mm/day. Interestingly, mean daily precipitation in the "wintertime pressure pattern" in early winter was greater than in midwinter. It is noted that such features were generally found even in the latter half of the analysis period when the warmer winter years appeared more frequently than in the former half. According to the case study for 1983/84 winter, although the "wintertime pressure pattern" appeared rather frequently already from early November, each event of that pattern tended to persist only a several days. In addition, the organization of the shallow convective clouds in the cold air outbreak situation as often found in midwinter was not clearly observed. However, strong cold air advection in early winter as in midwinter over the warm underlying sea, at least in the mature stage of each "wintertime pressure situation", seems to enable the extremely huge amount of LH and the equivalently intense SH to that in midwinter, resulting in the large daily precipitation there through the enhancement of the air mass transformation process over the Japan Sea.

Kato, Kuranoshin; Nishimura, Nanako; Haga, Yuichi

2014-05-01

77

Shelf circulation prior to and post a cold front event measured from vessel-based acoustic Doppler current profiler  

NASA Astrophysics Data System (ADS)

Shelf circulation impacted by a shift in wind regime during the passage of an atmospheric cold front system is studied with a field survey over the mid-shelf of the South Atlantic Bight between Oct 4 and 9, 2004. Weak southerly winds preceded the cold front for a few days, followed by a rapid shift in wind direction and strengthening of northeasterly winds over a few more days. More than 93 h of acoustic Doppler current profiler (ADCP) data were obtained along an equilateral triangle of 105 km in perimeter, which was continuously occupied for 11 times. A harmonic analysis was applied to extract tidal and subtidal wind-driven flow components by collapsing the 93 hour data into one M2 tidal period. It was found that the cross-shelf flow was barely affected by the wind while the along-shelf flow responded with a spatially uniform and almost steadily increasing mean flow velocity, superimposed on an oscillatory tidal current. The wind induced along-shelf transport was estimated to be ~ 0.3 Sv over the inner and middle shelf. The net cross-shelf transport was negligible. Apparently, the northeasterly wind causes an along-shelf current which was subject to Coriolis force that sets up an increasing coastal sea level pressure gradient as the water kept piling up against the coast, which was confirmed by tide gauge data. The observations found that the flow field prior to the strong winds had more complicated structures including eddy-like features, while after the strong northeasterly winds, the flow became eddy free and uniform in space. A theoretical model solved by a Laplace Transform was used to examine the wind-driven flow mechanism and the results were compared with the observations of net along-shelf flow velocity.

Li, Chunyan; Chen, Changsheng

2014-11-01

78

Proteins Involved in Distinct Phases of Cold Hardening Process in Frost Resistant Winter Barley (Hordeum vulgare L.) cv Luxor  

PubMed Central

Winter barley is an economically important cereal crop grown in higher latitudes and altitudes where low temperatures represent an important environmental constraint limiting crop productivity. In this study changes in proteome of leaves and crowns in a frost tolerant winter barley cv. Luxor in relation to short and long term periods of cold followed by a brief frost treatment were studied in order to disclose proteins responsible for the cold hardening process in distinct plant tissues. The mentioned changes have been monitored using two dimensional difference gel electrophoresis (2D-DIGE) with subsequent peptide-mapping protein identification. Regarding approximately 600–700 distinct protein spots detected on 2D gels, there has been found at least a two-fold change after exposure to low temperatures in about 10% of proteins in leaves and 13% of proteins in crowns. Protein and nitrogen metabolic processes have been influenced by low temperature to a similar extent in both tissues while catabolism, carbohydrate metabolism and proteins involved in stress response have been more affected in crowns than in leaves. The range of changes in protein abundance was generally higher in leaves and chloroplast proteins were frequently affected which suggests a priority to protect photosynthetic apparatus. Overall, our data proved existence of slightly different response strategies to low temperature stress in crowns and leaves, i.e., tissues with different biological role. Moreover, there have been found several proteins with large increase in accumulation, e.g., 33 kDa oxygen evolving protein of photosystem II in leaves and “enhanced disease susceptibility 1” in crowns; these proteins might have potential to indicate an enhanced level of frost tolerance in barley.

Hlavackova, Iva; Vitamvas, Pavel; Santrucek, Jiri; Kosova, Klara; Zelenkova, Sylva; Prasil, Ilja Tom; Ovesna, Jaroslava; Hynek, Radovan; Kodicek, Milan

2013-01-01

79

Has a warm North Atlantic contributed to recent European cold winters?  

NASA Astrophysics Data System (ADS)

The rise of global surface temperature waned during the last decade, despite increasing greenhouse gas concentrations. The temperature changes were most pronounced over northern hemisphere land masses during winter (Cohen et al 2012). They were largely associated with weakening of the mid-latitude westerly flow. To some, these temperature changes may seem paradoxical in the light of anthropogenic global warming, and thus there is much interest in explaining them. Peings and Magnusdottir (2014 Environ. Res. Lett. 9 034018) provide evidence that recent warming of the North Atlantic sea surface temperature (SST) may be part of the explanation.

Keenlyside, Noel; Omrani, Nour-Eddine

2014-05-01

80

Proteome analysis of cold response in spring and winter wheat (Triticum aestivum) crowns reveals similarities in stress adaptation and differences in regulatory processes between the growth habits.  

PubMed

A proteomic response to cold treatment (4 °C) has been studied in crowns of a frost-tolerant winter wheat cultivar Samanta and a frost-sensitive spring wheat cultivar Sandra after short-term (3 days) and long-term (21 days) cold treatments. Densitometric analysis of 2-D differential in gel electrophoresis (2D-DIGE) gels has resulted in the detection of 386 differentially abundant protein spots, which reveal at least a two-fold change between experimental variants. Of these, 58 representative protein spots have been selected for MALDI-TOF/TOF identification, and 36 proteins have been identified. The identified proteins with an increased relative abundance upon cold in both growth habits include proteins involved in carbohydrate catabolism (glycolysis enzymes), redox metabolism (thioredoxin-dependent peroxidase), chaperones, as well as defense-related proteins (protein revealing similarity to thaumatin). Proteins exhibiting a cold-induced increase in the winter cultivar include proteins involved in regulation of stress response and development (germin E, lectin VER2), while proteins showing a cold-induced increase in the spring cultivar include proteins involved in restoration of cell division and plant growth (eIF5A2, glycine-rich RNA-binding protein, adenine phosphoribosyltransferase). These results provide new insights into cold acclimation in spring and winter wheat at the proteome level and enrich our previous work aimed at phytohormone dynamics in the same plant material. PMID:24047233

Kosová, Klára; Vítámvás, Pavel; Planchon, Sébastien; Renaut, Jenny; Vanková, Radomíra; Prášil, Ilja Tom

2013-11-01

81

Transient and local weakening of surface winds observed above the Kuroshio front in the winter East China Sea  

NASA Astrophysics Data System (ADS)

confirm whether surface winds strengthen above warm waters around oceanic fronts using in situ data, a field measurement was conducted using both expendable bathythermographs and Global Positioning System sondes released concurrently across the Kuroshio front in the East China Sea in December 2010. In contrast to previous studies mainly based on satellite observations, the finding of the present field survey is the local weakening of surface winds at the northern flank of the Kuroshio front. From the above field observation in conjunction with a regional numerical model experiment, it is suggested that the northwesterly winds crossing the Kuroshio front from the cooler side first weaken at the northern flank of the front because of the onset of upward transfer of the "nonslip" condition at the sea surface. Thereafter, as the atmospheric mixed layer with warm and humid air mass develops gradually downwind over the Kuroshio region, the surface winds are gradually accelerated by the momentum mixing with strong winds aloft. The surface winds remain strong over the cool East China Sea shelf, and it is thus considered that the surface winds only weaken at the northern flank of the Kuroshio front. However, numerical modeling indicates that this local weakening of the surface winds occurs as a transient state with a short duration and such a structure has thus rarely been detected in the long-term averaged wind fields observed by satellites.

Kasamo, Kenki; Isobe, Atsuhiko; Minobe, Shoshiro; Manda, Atsuyoshi; Nakamura, Hirohiko; Ogata, Koto; Nishikawa, Hatsumi; Tachibana, Yoshihiro; Kako, Shin'ichiro

2014-02-01

82

Extreme Winter Cold Temperatures In Madrid (spain). A Relationship With NAO Extreme Years  

Microsoft Academic Search

The minimum daily temperature series of Madrid, has been analysed for the period 1963-1999, to determine the extremely cold days (ECD), i.e.: 5 % coldest days from November to March. The annual frequency varies from 23 ECD in 1968 to zero oc- currence in four years: 1966, 1988,1996 and 1998. It has been found that 5 synoptic patterns can produce

L. Prieto; R. García; J. Díaz; E. Hernández; P. Ribera; T. del Teso

2002-01-01

83

IRREGULAR SLOSHING COLD FRONTS IN THE NEARBY MERGING GROUPS NGC 7618 AND UGC 12491: EVIDENCE FOR KELVIN-HELMHOLTZ INSTABILITIES  

SciTech Connect

We present results from two {approx}30 ks Chandra observations of the hot atmospheres of the merging galaxy groups centered around NGC 7618 and UGC 12491. Our images show the presence of arc-like sloshing cold fronts (CFs) wrapped around each group center and {approx}100 kpc long spiral tails in both groups. Most interestingly, the CFs are highly distorted in both groups, exhibiting 'wings' along the fronts. These features resemble the structures predicted from non-viscous hydrodynamic simulations of gas sloshing, where Kelvin-Helmholtz instabilities (KHIs) distort the CFs. This is in contrast to the structure seen in many other sloshing and merger CFs, which are smooth and featureless at the current observational resolution. Both magnetic fields and viscosity have been invoked to explain the absence of KHIs in these smooth CFs, but the NGC 7618/UGC 12491 pair are two in a growing number of both sloshing and merger CFs that appear distorted. Magnetic fields and/or viscosity may be able to suppress the growth of KHIs at the CFs in some clusters and groups, but clearly not in all. We propose that the presence or absence of KHI distortions in CFs can be used as a measure of the effective viscosity and/or magnetic field strengths in the intracluster medium.

Roediger, E. [School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany); Kraft, R. P.; Machacek, M. E.; Forman, W. R.; Nulsen, P. E. J.; Jones, C.; Murray, S. S., E-mail: e.roediger@jacobs-university.de [Harvard/Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-08-01

84

Dominant black-capped chickadees pay no maintenance energy costs for their wintering status and are not better at enduring cold than subordinate individuals.  

PubMed

Winter requires physiological adjustments in northern resident passerines. Cold acclimatization is generally associated with an increase in physiological maintenance costs, measured as basal metabolic rate (BMR), and cold endurance, reflected by summit metabolic rate (M(sum)). However, several northern species also form social groups in winter and a bird's hierarchical position may influence the size of its metabolically active organs as well as its BMR. Winter metabolic performance in these species may therefore reflect a complex set of adjustments to both seasonal climatic variations and social environment. We studied the effect of social status on parameters of cold acclimatization (body mass, size of fat reserves and pectoral muscles, BMR and M(sum)) in free-living black-capped chickadees (Poecile atricapillus). Birds that were structurally large and heavy for their body size, mostly dominant individuals, carried more fat reserves and had larger pectoral muscles. However, social status had little effect on metabolic performance in the cold. Indeed, M(sum) was independent of social rank while mass-corrected BMR was slightly lower in dominant individuals, likely due to a statistical dilution effect caused by large metabolically inactive fat reserves. BMR and M(sum), whether considered in terms of whole-animal values, corrected for body mass or body size were nevertheless correlated, suggesting a functional link between these metabolic components. Our results therefore indicate that the energy cost of social dominance is not a generalized phenomenon in small wintering birds. PMID:22037961

Lewden, Agnès; Petit, Magali; Vézina, François

2012-04-01

85

European cold winter 2009-2010: How unusual in the instrumental record and how reproducible in the ARPEGE-Climat model?  

NASA Astrophysics Data System (ADS)

Boreal winter 2009-2010 made headlines for cold anomalies in many countries of the northern mid-latitudes. Northern Europe was severely hit by this harsh winter in line with a record persistence of the negative phase of the North Atlantic Oscillation (NAO). In the present study, we first provide a wider perspective on how unusual this winter was by using the recent 20th Century Reanalysis. A weather regime analysis shows that the frequency of the negative NAO was unprecedented since winter 1939-1940, which is then used as a dynamical analog of winter 2009-2010 to demonstrate that the latter might have been much colder without the background global warming observed during the twentieth century. We then use an original nudging technique in ensembles of global atmospheric simulations driven by observed sea surface temperature (SST) and radiative forcings to highlight the relevance of the stratosphere for understanding if not predicting such anomalous winter seasons. Our results demonstrate that an improved representation of the lower stratosphere is necessary to reproduce not only the seasonal mean negative NAO signal, but also its intraseasonal distribution and the corresponding increased probability of cold waves over northern Europe.

Ouzeau, G.; Cattiaux, J.; Douville, H.; Ribes, A.; Saint-Martin, D.

2011-06-01

86

The cold European winter of 2005-2006 assisted the spread and persistence of H5N1 influenza virus in wild birds.  

PubMed

In January 2006, a major cold spell affected Europe, coinciding with an increase of H5N1 influenza virus detected in wild birds, mostly dead mute swans, starting along the River Danube and the Mediterranean coast line. Subsequently H5N1 detections in wild birds were concentrated in central and western parts of Europe, reaching a peak in mid February. We tested the hypothesis that the geographic distribution of these H5N1 infections was modulated by the long-term wintering line, the 0 °C isotherm marking the limit beyond which areas are largely unsuitable for wintering waterfowl. Given the particularly cold 2005-2006 European winter, we also considered the satellite-derived contemporary frost conditions. This brought us to select the long-term maximum rather than the mean January 0 °C isotherm as the best approximation for the 2005-2006 wintering line. Our analysis shows that H5N1 detection sites were closer to the wintering line than would be expected by chance, even when the geographic distribution of water bird wintering sites was accounted for. We argue that partial frost conditions in water bodies are conducive to bird congregation, and this may have enhanced H5N1 transmission and local spread. Because the environmental virus load also would build up in these hot spots, H5N1 virus may have readily persisted during the spring, at least in cooler areas. We conclude that H5N1 introduction, spread, and persistence in Europe may have been enhanced by the cold 2005-2006 winter. PMID:20686815

Ottaviani, Daniela; de la Rocque, S; Khomenko, S; Gilbert, M; Newman, S H; Roche, B; Schwabenbauer, K; Pinto, J; Robinson, T P; Slingenbergh, J

2010-06-01

87

Pretreatment of landfill leachate using deep shaft aeration bioreactor (DSAB) in cold winter season.  

PubMed

A pilot-scale deep shaft aeration bioreactor (DSAB) with 110 m in depth and 0.5m in diameter for the pretreatment of landfill leachate in winter was operated at a daily treatment scale of around 10-20 tons. It was found that the performance of the DSAB mainly depended on the inflow loads and concentrations of pollutants. NH3-N, TN, COD, TOC removals of 66-94%, 41-64%, 67-87%, 55-92% at organic load rate of 1.7-9.4 g CODL(-1)day(-1) and hydraulic retention time of 1-2d were obtained using DSAB, respectively, with the lowest ambient temperature of -3 °C. The effluent COD can be reduced to below 1000 mg/L, an acceptable level for advanced treatment using reverse osmosis system, when the influent COD was below 7000 mg/L at 10t/d. The EEM and GPC analysis implied that the non-biodegradable contaminants such as humic- and fulvic-like DOM dominated in the organic fractions of the effluent, which rendered the biological treatment ineffective. Compared with 20-40% removals obtained using traditional biological processes below 15 °C, DSAB showed a higher treatment efficiency for COD and NH3-N, even though at adverse conditions of poor carbon source, lower C/N ratio and high nitrite concentrations in the leachate of test. PMID:23542320

Niu, Jing; Zhang, Tongju; He, Yijia; Zhou, Haiyan; Zhao, Aihua; Zhao, Youcai

2013-05-15

88

Southern hemisphere winter cold-air mesocyclones: climatic environments and associations with teleconnections  

NASA Astrophysics Data System (ADS)

Cold-air mesocyclones remain a forecasting challenge in the southern hemisphere middle and higher latitudes, where conventional observations are lacking. One way to improve mesocyclone predictability is to determine their larger-scale circulation environments and associations with teleconnection patterns. To help realize this objective, reanalysis datasets on atmospheric and upper-ocean synoptic variables important in mesocyclone development are composited and compared to previously published mesocyclone spatial inventories. These analyses demonstrate a consistent association between higher frequencies of mesocyclones, greater sea ice extent and large positive differences in the SST minus low-altitude air temperature fields, coinciding with enhanced westerly low-level winds having a southerly component. Composites in the 1979 2001 period also were formed for opposite phases of El Niño Southern Oscillation (ENSO), the Southern Annular Mode (SAM) and the Trans-Polar Index (TPI). Regions likely to be favorable for mesocyclone development relative to climatology were identified. The largest (smallest) variations in meso-cyclogenesis occur in the South Pacific (South Indian Ocean, south of Australia), and are dominated by ENSO. The SAM and TPI are of secondary importance, yet still influential, and exhibit strong regional-scale variations.

Claud, C.; Carleton, A. M.; Duchiron, B.; Terray, P.

2009-08-01

89

2012/13 abnormal cold winter in Japan associated with Large-scale Atmospheric Circulation and Local Sea Surface Temperature over the Sea of Japan  

NASA Astrophysics Data System (ADS)

On Japan, wintertime cold wave has social, economic, psychological and political impacts because of the lack of atomic power stations in the era of post Fukushima world. The colder winter is the more electricity is needed. Wintertime weather of Japan and its prediction has come under the world spotlight. The winter of 2012/13 in Japan was abnormally cold, and such a cold winter has persisted for 3 years. Wintertime climate of Japan is governed by some dominant modes of the large-scale atmospheric circulations. Yasunaka and Hanawa (2008) demonstrated that the two dominant modes - Arctic Oscillation (AO) and Western Pacific (WP) pattern - account for about 65% of the interannual variation of the wintertime mean surface air temperature of Japan. A negative AO brings about cold winter in Japan. In addition, a negative WP also brings about cold winter in Japan. Looking back to the winter of 2012/13, both the negative AO and negative WP continued from October through December. If the previous studies were correct, it would have been extremely very cold from October through December. In fact, in December, in accordance with previous studies, it was colder than normal. Contrary to the expectation, in October and November, it was, however, warmer than normal. This discrepancy signifies that an additional hidden circumstance that heats Japan overwhelms these large-scale atmospheric circulations that cool Japan. In this study, we therefore seek an additional cause of wintertime climate of Japan particularly focusing 2012 as well as the AO and WP. We found that anomalously warm oceanic temperature surrounding Japan overwhelmed influences of the AO or WP. Unlike the inland climate, the island climate can be strongly influenced by surrounding ocean temperature, suggesting that large-scale atmospheric patterns alone do not determine the climate of islands. (a) Time series of a 5-day running mean AO index (blue) as defined by Ogi et al., (2004), who called it the SVNAM index. For reference, the conventional AO index is shown by the gray line. (b) a 5-day running mean WP index, (c) area-averaged Surface Air Temperature anomalies in Japan, (d) Air Temperature anomalies, (e) heat flux anomalies, and (f) Sea Surface Temperature anomalies. The boxed area on the Sea of Japan indicates the area in which the (d)-(f) indexes were calculated.

Ando, Y.; Ogi, M.; Tachibana, Y.

2013-12-01

90

Spin-Probe Studies during Freezing of Cells Isolated from Cold-Hardened and Nonhardened Winter Rye 12  

PubMed Central

Mesophyll cells isolated from cold-hardened and nonhardened winter rye (Secale cereale L. cv. Puma) were spin-labeled with the fatty-acid spin probe N-oxyl-4,4-dimethyloxazolidine 5-ketostearic acid. The probe was intercalated within the cellular membranes and changes in probe motion were followed during extracellular freezing of the cells. A correlation was observed between the lethal freezing temperatures (LT50) of the cells and the maximum hyperfine splitting value achieved by the incorporated probe. Rigid limit spectra indicated that a more ordered average packing was attained by membranes of hardened cells which survived freezing to lower temperatures. Nonhardened cells fixed with osmic acid at lethal freezing temperatures, in the frozen state, showed both conversion of normal bilayered cellular membrane ultrastructure to an amorphous state and condensation of cellular membranes to form densely packed multibilayered vesicles. Taken together with the spin-labeling data, these results suggest that at least one molecular mechanism of extracellular freezing injury involves the irreversible conversion of planar membrane bilayers to structures having less ordered packing and increased surface curvatures. Images

Singh, Jas; Miller, Richard W.

1982-01-01

91

Cold priming drives the sub-cellular antioxidant systems to protect photosynthetic electron transport against subsequent low temperature stress in winter wheat.  

PubMed

Low temperature seriously depresses the growth of wheat through inhibition of photosynthesis, while earlier cold priming may enhance the tolerance of plants to subsequent low temperature stress. Here, winter wheat plants were firstly cold primed (5.2 °C lower temperature than the ambient temperature, viz., 10.0 °C) at the Zadoks growth stage 28 (i.e. re-greening stage, starting on 20th of March) for 7 d, and after 14 d of recovery the plants were subsequently subjected to a 5 d low temperature stress (8.4 °C lower than the ambient temperature, viz., 14.1 °C) at the Zadoks growth stage 31 (i.e. jointing stage, starting on 8th April). Compared to the non-primed plants, the cold-primed plants possessed more effective oxygen scavenging systems in chloroplasts and mitochondria as exemplified by the increased activities of SOD, APX and CAT, resulting in a better maintenance in homeostasis of ROS production. The trapped energy flux (TRO/CSO) and electron transport (ETO/CSO) in the photosynthetic apparatus were found functioning well in the cold-primed plants leading to higher photosynthetic rate during the subsequent low temperature stress. Collectively, the results indicate that cold priming activated the sub-cellular antioxidant systems, depressing the oxidative burst in photosynthetic apparatus, hereby enhanced the tolerance to subsequent low temperature stress in winter wheat plants. PMID:24887010

Li, Xiangnan; Cai, Jian; Liu, Fulai; Dai, Tingbo; Cao, Weixing; Jiang, Dong

2014-09-01

92

Reduced Sea Ice and its link to frequent intraseasonal cold air outbreak during the 2009-2010 abnormal winter in Japan and East Asia  

NASA Astrophysics Data System (ADS)

In the winter of 2009/2010, Japan and the East Asian region experienced an abnormally frequent occurrence of cold air outbreaks. Although the winter averaged temperature in the Japan Honshu islands was slightly positive (+0.81C for DJF average and +0.71C for NDJFM average), repeated decline in temperature was notable from November 2009 even through April 2010 (Fig1). One explanation for this abnormal winter season is the extreme negative condition of the Northern Hemisphere Annular Mode (NAM) that persisted from December to mid-January which marks a reversal of air mass between the Arctic and mid-latitudes. However, more explanation is needed to explain why such variability was prominent in the intraseasonal timescale and especially in Japan and East Asian region. Prior to a particular case of the cold air outbreak which reached Japan on Dec. 17, an anomalous ridge formed in western Siberia which matured into a strong high pressure anomaly in the Barents sea. Cyclonic wind anomaly accompanying this high pressure anomaly created a cold air advection from the Arctic Ocean which lead up to the cold air buildup over western Siberia. The pressure anomaly subsequently shifted westward to mature into a blocking high which created a wave-train pattern downstream advecting the cold air buildup eastward toward East Asia and Japan (Fig2). Variant of such process of cold air buildup and advection was seen throughout the winter season. Intensification of high pressure anomaly over the Barents sea was concurrent with the negative anomaly in sea ice coverage and discharge of heat flux. This study suggests that there is a strong and systematic linkage between the Arctic Ocean and the cold air outbreak over East Asia and Japan which we will focus upon in our presentation. Timeseries of temperature anomaly based on 58 stations in the main islands of Japan (above) and the daily NAM index (below). 500hPa geopotential height (contours) and 850hPa temperature anomaly (shades) regressed on the Novmenber to Marcch daily temperature over the Japan region with 10, 5, 1 day lag respectively preceding the cold air outbreak.

Hori, M. E.; Inoue, J.; Kikuchi, T.; Tachibana, Y.

2010-12-01

93

Winter Weather Emergencies  

MedlinePLUS

Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

94

A Winter Survival Unit.  

ERIC Educational Resources Information Center

The article is a condensation of materials from the winter survival unit of a Canadian snow ecology course. The unit covers: cold physiology, frostbite, snowblindness, hypothermia, winter campout, and survival strategies. (SB)

Phillips, Ronald E.

1979-01-01

95

Gelation in protein extracts from cold acclimated and non-acclimated winter rye (Secale cereale L. cv Musketeer).  

PubMed

A protein gel is a three-dimensional network consisting of molecular interactions between biopolymers that entrap a significant volume of a continuous liquid phase (water). Molecular interactions in gels occur at junction zones within and between protein molecules through electrostatic forces, hydrogen bonding, hydrophobic associations (van der Waals attractions) and covalent bonding. Gels have the physicochemical properties of both solids and liquids, and are extremely important in the production and stability of a variety of foods, bioproducts and pharmaceuticals. In this study, gelation was induced in phenol extracted protein fractions from non-acclimated (NA) and cold-acclimated (CA) winter rye (Secale cereale L. cv Musketeer) leaf tissue after repeated freeze-thaw treatments. Gel formation only occurred at high pH (pH 12.0) and a minimum of 3-4 freeze-thaw cycles were required. The gel was thermally stable and only a specific combination of chemical treatments could disrupt the gel network. SDS-PAGE analysis identified ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) as the major protein component in the gel, although Rubisco itself did not appear to be a factor in gelation. Raman spectroscopy suggested changes in protein secondary structure during freeze-thaw cycles. Overall, the NA and CA gels were similar in composition and structure, with the exception that the CA gel appeared to be amyloidic in nature based on thioflavin T (ThT) fluorescence. Protein gelation, particularly in the apoplast, may confer protection against freeze-induced dehydration and potentially have a commercial application to improve frozen food quality. PMID:23348601

Lim, Ze Long; Low, Nicholas H; Moffatt, Barbara A; Gray, Gordon R

2013-04-01

96

A Investigation of Colorado Front Range Winter Storms Using a Nonhydrostatic Mesoscale Numerical Model Designed for Operational Use  

NASA Astrophysics Data System (ADS)

State-of-the-art data sources such as Doppler radar, automated surface observations, wind profiler, digital satellite, and aircraft reports are for the first time providing the capability to generate real-time, operational three-dimensional gridded data sets with sufficient spatial and temporal resolutions to diagnose the structure and evolution of mesoscale systems. A prototype data assimilation system of this type, called the Local Analysis and Prediction System (LAPS), is being developed at the National Oceanic and Atmospheric System's Forecast Systems Laboratory (FSL). The investigation utilizes the three-dimensional LAPS analyses for initialization of the full physics, nonhydrostatic Regional Atmospheric Modeling System (RAMS) model developed at the Colorado State University to create a system capable of generating operational mesoscale predictions. The LAPS/RAMS system structured for operational use can add significant value to existing operational model output and can provide an improved scientific understanding of mesoscale weather events. The results are presented through two case study analyses, the 7 January 1992 Colorado Front Range blizzard and the 8-9 March 1992 eastern Colorado snow storm. Both cases are ideal for this investigation due to the significant mesoscale variation observed in the precipitation and flow structure. The case study results demonstrate the ability to successfully detect and predict mesoscale features using a mesoscale numerical model initialized with high resolution (10 km horizontal grid interval), non-homogeneous data. The strong influence of the Colorado topography on the resultant flow is suggested by the generation of a lee vortex that frequently develops east of the Front Range and south of the Cheyenne Ridge in stable, northwest synoptic flow. The lee vortex exhibits surface flow characteristics that are similar to results from low Froude number flow around an isolated obstacle. A series of numerical experiments using RAMS with idealized topography and horizontally homogeneous initial conditions are presented to investigate typical low Froude number flow characteristics in the vicinity of barriers representative of the Colorado topography. The results are compared to the findings of previous investigations and to the case study observations and numerical predictions.

Snook, John Stover

97

Numerical simulations of the transport and diffusion during the 1991 Winter Validation Study along the Front Range in Colorado  

SciTech Connect

An important aspect of the US Department of Energy`s Atmospheric Studies in Complex Terrain (ASCOT) program is the development and evaluation of numerical models that predict transport and diffusion of pollutants in complex terrain. Operational mesoscale modeling of the transport of pollutants in complex terrain will become increasingly practical as computational costs decrease and additional data from high-resolution remote sensing instrumentation networks become available during the 1990s. Four-dimensional data assimilation (4DDA) techniques are receiving a great deal of attention recently not only to improve the initial conditions of mesoscale forecast models, but to create high-quality four-dimensional mesoscale analysis fields that can be used as input to air-quality models. In this study, a four-dimensional data assimilation technique based on Newtonian relaxation is incorporated into the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) and evaluated using data taken from one experiment of the 1991 ASCOT field study along the front range of the Rockies in Colorado. The main objective of this study is to compare the observed surface concentrations with those predicted by a Lagrangian particle dispersion model and to demonstrate the effect of data assimilation on the simulated plume. In contrast to pervious studies in which the smallest horizontal grid spacing was 10 km (Stauffer and Seaman, 1991) and 8 km (Yamada and Hermi, 1991), data assimilation is applied in this study to domains with a horizontal grid spacing as small as 1 km.

Fast, J.D.; O`Steen, B.L.

1992-11-01

98

Numerical simulations of the transport and diffusion during the 1991 Winter Validation Study along the Front Range in Colorado  

SciTech Connect

An important aspect of the US Department of Energy's Atmospheric Studies in Complex Terrain (ASCOT) program is the development and evaluation of numerical models that predict transport and diffusion of pollutants in complex terrain. Operational mesoscale modeling of the transport of pollutants in complex terrain will become increasingly practical as computational costs decrease and additional data from high-resolution remote sensing instrumentation networks become available during the 1990s. Four-dimensional data assimilation (4DDA) techniques are receiving a great deal of attention recently not only to improve the initial conditions of mesoscale forecast models, but to create high-quality four-dimensional mesoscale analysis fields that can be used as input to air-quality models. In this study, a four-dimensional data assimilation technique based on Newtonian relaxation is incorporated into the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) and evaluated using data taken from one experiment of the 1991 ASCOT field study along the front range of the Rockies in Colorado. The main objective of this study is to compare the observed surface concentrations with those predicted by a Lagrangian particle dispersion model and to demonstrate the effect of data assimilation on the simulated plume. In contrast to pervious studies in which the smallest horizontal grid spacing was 10 km (Stauffer and Seaman, 1991) and 8 km (Yamada and Hermi, 1991), data assimilation is applied in this study to domains with a horizontal grid spacing as small as 1 km.

Fast, J.D.; O'Steen, B.L.

1992-01-01

99

Winter flounder antifreeze protein genes: demonstration of a cold-inducible promoter and gene transfer to other species  

Microsoft Academic Search

During the late fall and winter, the winter flounder produces a family of unique antifreeze proteins (AFP) to prevent the lethal formation of ice crystals in its blood. They have been able to induce winter flounder AFP mRNA synthesis in vivo by lowering the ambient temperature of the fish from 18°C in the summer months when AFP synthesis is at

R. C. Huang; B. Gourlie; J. Price

1987-01-01

100

German Front Experiment 1987: Observations and Preliminary Results.  

National Technical Information Service (NTIS)

The impact of the Alps on cold fronts was studied. The observational program was performed during five intensive observation periods when a cold front crossed central Europe. A reduced program was performed during one additional cold front event. An outli...

K. Hoinka H. Volkerts D. Heimann

1988-01-01

101

Significant relationships among frost tolerance and net photosynthetic rate, water use efficiency and dehydrin accumulation in cold-treated winter oilseed rapes.  

PubMed

Five winter oilseed rape cultivars (Benefit, Californium, Cortes, Ladoga, Navajo) were subjected to 30 days of cold treatment (4 °C) to examine the effect of cold on acquired frost tolerance (FT), dehydrin (DHN) content, and photosynthesis-related parameters. The main aim of this study was to determine whether there are relationships between FT (expressed as LT50 values) and the other parameters measured in the cultivars. While the cultivar Benefit accumulated two types of DHNs (D45 and D35), the other cultivars accumulated three additional DHNs (D97, D47, and D37). The similar-sized DHNs (D45 and D47) were the most abundant; the others exhibited significantly lower accumulations. The highest correlations were detected between LT50 and DHN accumulation (r=-0.815), intrinsic water use efficiency (WUEi; r=-0.643), net photosynthetic rate (r=-0.628), stomatal conductance (r=0.511), and intracellular/intercellular CO2 concentration (r=0.505). Those cultivars that exhibited higher Pn rate in cold (and further a significant increase in WUEi) had higher levels of DHNs and also higher FT. No significant correlation was observed between LT50 and E, PRI, or NDVI. Overall, we have shown the selected physiological parameters to be able to distinguish different FT cultivars of winter oilseed rape. PMID:24054752

Urban, Milan Old?ich; Klíma, Miroslav; Vítámvás, Pavel; Vašek, Jakub; Hilgert-Delgado, Alois Albert; Ku?era, Vratislav

2013-12-15

102

Analysis on seasonal retreat of Siberian high in association with that of the extremely cold Siberian air mass from winter to spring  

NASA Astrophysics Data System (ADS)

According to Kato et al.(2009), the seasonal increase in surface air temperature in the Japan Islands area attains the maximum due to the rapid weakening of the winter time large-scale circulation pattern from late March to early April. Although the rapid decrease in the appearance frequency of the daily Siberian high at that time was pointed out by them, seasonal retreat process of the the Siberian high and the Siberian air mass including in the their day-to-day variations from winter to spring have not been systematically understood yet. Thus the present study will examine the above phenomena by using mainly the NCEP/NCAR reanalysis data and the daily weather maps at the surface level provided by JMA. Although the climatological analyses are need in the future, the present study will perform a case study for the several years, 1984(cold winter), 2007(warm winter) and 2011(normal winter). The area with high appearance frequency of the surface anticyclone with its center pressure more than 1032hPa (roughly corresponding to the Siberian high) was found around 40N~60N/90~120E (including Lake Baykal area (50~55N/105~110E)) in January and February. Interestingly, the latitude of that high appearance area was not so changed in March. Furthermore its frequency decreased rapidly with its maximum latitude unchanged in April. However, while the high frequency area was mainly located in the colder region with 850hPa temperature (T850) lower than -15 degrees Celsius in January and February wider part of the area with high appearance frequency of the intense anticyclone distributed in the baroclinic zone with T850 higher than -15 degrees Celsius. In April, the -15 degrees Celsius isotherm of T850 moved further northward to ~60N, although the maximum frequency of the anticyclone was seen along ~50N. In addition, although the anticyclone associated with the daily Siberian high showed rather quasi-stationary-like character also in March (as well as in midwinter), the storm track was also found along that latitude to the east of ~110E at that time. As such, the present study implies that the frequent appearance area of the daily Siberian high changes in its relative location to the extremely cold area or the large temperature gradient zone to the south of it from winter to spring.

Hamaki, Tatsuya; Haga, Yuichi; Kato, Kuranoshin

2014-05-01

103

Nutrition for winter sports  

Microsoft Academic Search

Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable

Nanna L. Meyer; Melinda M. Manore; Christine Helle

2011-01-01

104

Plasma Membrane Lipid Alterations Associated with Cold Acclimation of Winter Rye Seedlings (Secale cereale L. cv Puma) 1  

PubMed Central

Highly enriched plasma membrane fractions were isolated from leaves of nonacclimated (NA) and acclimated (ACC) rye (Secale cereale L. cv Puma) seedlings. Collectively, free sterols, steryl glucosides, and acylated steryl glucosides constituted >50 mole% of the total lipid in both NA and ACC plasma membrane fractions. Glucocerebrosides containing hydroxy fatty acids constituted the major glycolipid class of the plasma membrane, accounting for 16 mole% of the total lipid. Phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine with lesser amounts of phosphatidylglycerol, phosphatidic acid, phosphatidylserine, and phosphatidylinositol, comprised only 32 mole% of the total lipid in NA samples. Following cold acclimation, free sterols increased from 33 to 44 mole%, while steryl glucosides and acylated steryl glucosides decreased from 15 to 6 mole% and 4 to 1 mole%, respectively. Sterol analyses of these lipid classes demonstrated that free ?-sitosterol increased from 21 to 32 mole% (accounting for the increase in free sterols as a class) at the expense of sterol derivatives containing ?-sitosterol. Glucocerebrosides decreased from 16 to 7 mole% of the total lipid following cold acclimation. In addition, the relative proportions of associated hydroxy fatty acids, including 22:0 (h), 24:0 (h), 22:1 (h), and 24:1 (h), were altered. The phospholipid content of the plasma membrane fraction increased to 42 mole% of the total lipid following cold acclimation. Although the relative proportions of the individual phospholipids did not change appreciably after cold acclimation, there were substantial differences in the molecular species. Di-unsaturated molecular species (18:2/18:2, 18:2/18:3, 18:3/18:3) of phosphatidylcholine and phosphatidylethanolamine increased following acclimation. These results demonstrate that cold acclimation results in substantial changes in the lipid composition of the plasma membrane.

Lynch, Daniel V.; Steponkus, Peter L.

1987-01-01

105

Winter World Explorations  

NSDL National Science Digital Library

Cold winter weather can cause us to retreat into our indoor shells biding our time until the warmer days return. However, there is much to explore outside during the wintertime and the following sites share some important reasons and cautionary tips for Winter World Explorations. The first website, Princeton University's Outdoor Action Guide to Winter Camping by Rick Curtis, provides a thorough overview of Winter Camping including sections on Winter Travel, Snowshoeing Basics, Winter Water, and more. This site also provides links to OA Guides for Winter Shelters, and Hypothermia and Cold Injuries (1). The second site, from the Search and Rescue Society of British Columbia deals specifically with Hypothermia including useful information on Physiology, Signs, Symptoms, and Treatment Considerations (2). The third website, SnowSchool, is an innovative educational field program designed for 4th and 5th graders where "kids venture out into America's winter wildlands to discover all the living creatures under the snow." SnowSchool is a program of Winter Wildlands Alliance and "the nation's largest on-snow winter ecology education program" with 27 sites across the United States (3). The fourth website from the Minnesota DNR is a feature on Winter Bird Feeding which includes specific information about Winter Foods, Seeds and Mixes, Suet, Feeders, and Winter Feeder Layout (4). The fifth website, The Native Conifers of North America, is an excellent and very comprehensive online introduction and field guide to conifer species native to North America. The site includes A Key to the Genera and Species, sections on Selected Conifers from Different Parts of North America, and many beautiful photographs and line drawings (5). The sixth website (6) hosts an article on Winter Nutrition: Tips for people who exercise in the cold by nutrition counselor Nancy Clark, MS, RD. In her article, Ms. Clark answers common winter exercise questions like Why do I shiver when I get cold?, and Why do I feel hungrier in the winter than in the summer? Speaking of being hungrier in the winter, the final two websites offer recipes for winter stews and soups, a perfect way to end a day of winter exploring. One website offers a Hearty Winter Stew recipe from the University of Michigan Health System-Nutrition Services (7}. The other website, from The Ohio State University Extension -- Family Nutrition Program Newsletter tells us that January is National Soup Month, and offers recipes for stews, soups, and even instructions for bread soup bowls (8).

106

Progress of snow mould infection in crowns of winter rye (Secale cereale L.) is related to photosynthetic activity during cold acclimation.  

PubMed

Resistance to snow mould is a feature determined by multiple genes. Therefore, determining the phenotype of resistant plants is difficult as it requires an investigation over a long period of time from cold acclimation through pathogenesis. The aim of the present study was (i) to determine the characteristics of the resistant genotype and (ii) to clarify the connections between photosynthesis during cold acclimation and then pathogenesis caused by Microdochium nivale. Two inbred lines of winter rye (Secale cereale L.) differing in their susceptibility to snow mould were used in the study. After cold acclimation snow mould resistant (SMR) line was characterised by higher values of CO2 assimilation and electron transport efficiency but did not differ from snow mould susceptible (SMS) line in carboxylation rate of RuBisCO (Vcmax). Higher soluble carbohydrate accumulation, due to higher photosynthesis intensity, as well as an ABA increase at 5 days post infection (DPI) in leaves and crowns were found in SMR line during the pathogenesis period. Callose deposition was found around non-infected bundle sheets and in cortex cells at 5 DPI (at the same time point as ABA peak) only in SMR line, which probably prevented the infection of leaf initials. Early leaf initials infection in SMS line may be responsible for inhibiting leaf growth and plant regeneration after stress cessation. The results show different physiological and biochemical characteristics of the investigated lines, which can be applied in the selection of resistant genotypes and identifying genomic regions responsible for metabolic pathways increasing pathogen resistance. PMID:23820028

Pociecha, E; Janowiak, F; Dubas, E; ?ur, I; Tokarz, K; Kolasi?ska, I; P?a?ek, A

2013-09-01

107

The effects of a mid-winter 8-week course of sub-sunburn sunbed exposures on tanning, vitamin D status and colds.  

PubMed

Like UV irradiation, which generates vitamin D(3) in the skin, the hormonally active metabolite, 1,25-dihydroxyvitamin D(3), boosts innate immunity against viruses and bacteria. Epidemiologic studies have found high vitamin D levels to be associated with lower risk of infections of the upper respiratory tract (colds). We have therefore performed an intervention study in 105 young adults (ages 18-30 years; 91% female) over a mid-winter 8-week period (January-March 2010). The participants were randomised to 3 groups: (A) subjected to 3 times a week sub-sunburn sunbed exposure (n = 35), (B) daily vitamin D supplementation, @ 1000 IU (n = 37), and (C) a control group without any intervention (n = 33). The mean serum level of 25-hydroxyvitamin D (25(OH)D) dropped from 62 to 55 nmol l(-1) in group C, while these levels rose from 62 to 109 and from 58 to 93 nmol l(-1) in groups A and B, respectively (p < 0.001). The skin on the chest darkened significantly in group A (mean difference in lightness, L*, equalled -5.7, p < 0.001), correlating significantly, but weakly, with increases in 25(OH)D (3.3 nmol l(-1) per unit drop in L*, R(2) = 0.17, p = 0.014). The percentage of self-reported colds with proper signs and symptoms was only slightly and not significantly reduced in groups A and B in comparison to group C: 57 and 51 versus 67%, respectively. Hence, the sub-sunburn sunbed treatment was effective in tanning and increasing the 25(OH)D serum level, more so than 1000 IU per day, but had no appreciable effect on colds. PMID:23104230

de Gruijl, Frank R; Pavel, Stan

2012-12-01

108

Winter Sports Medicine,  

National Technical Information Service (NTIS)

Outdoor sporting activities in winter are becoming more popular. There is a significant threat to individuals being hurt or going out unprepared for the rigors of cold weather environment. The injuries of chilblain, trenchfoot, frostbite and hypothermia a...

M. P. Hamlet

1988-01-01

109

Ergebnisse des Experiments Merkur: Strukturaenderung Einer Schwachen Kaltfront im Einflussbereich der Alpen (Results of the Experiment Merkur: Structural Change of a Weak Cold Front in the Sphere of Influence of the Alps).  

National Technical Information Service (NTIS)

The structure of a weak cold front was investigated in the mountains and at the frontier region between mountains and foreland in the framework of the international Alpine Experiment (ALPEX). The general weather development in the period of the MERKUR mea...

C. Freytag

1987-01-01

110

Validation and analysis of high-resolution atmospheric model simulations of the cold Bora outbreak over the Northern Adriatic Sea in winter 2012  

NASA Astrophysics Data System (ADS)

The Adriatic Sea is regularly affected by cold and strong Bora winds blowing from the north-east, especially during the winter season. These events are characterized by intense surface heat loss and air-sea exchange, thus producing strong effects on the circulation of the Adriatic, triggering dense water formation and driving basin-scale gyres. Turbulent surface (latent and sensible) heat fluxes and Sea Surface Temperature (SST) are the two most important parameters that characterize intense air-sea interactions typical of Bora events, and their accurate simulation is required in order to properly describe and understand atmospheric and ocean circulation processes. This study deals mainly with the atmospheric component of the modelling system available in the framework of the flagship Project "RITMARE", and presents the results of an application focused on the exceptional Bora episode occurred in winter 2012 (25 January-15 February). A number of short-range high-resolution atmospheric simulations have been performed to cover the entire period. Model performances have been evaluated in terms of variables of interest for oceanographic applications. As far as meteorological variables, surface fluxes and SST are concerned, the validation has been undertaken trough a comparison with available surface data (buoys) and satellite-derived SST, while Synthetic Aperture Radar (SAR) products have been used to assess modelled wind fields. Two mesoscale operational-like modelling chains have been implemented, one based on BOLAM-MOLOCH models, the other on WRF. The use of different initial and boundary conditions provided by two global NWP systems, namely GFS (NCEP) and IFS (ECWMF), driving the high-resolution simulations turned out to have a remarkable impact on the results, mainly as a consequence of a different initialization of the SST field. Results suggest the importance of adopting full bi-directional coupling between atmospheric and ocean circulation models at least in this semi-enclosed basin during extreme events.

Stocchi, Paolo; Davolio, Silvio; Marcello Miglietta, Mario; Carniel, Sandro; Benetazzo, Alvise; Li, Xiao-Ming; Bohm, Emanuele

2014-05-01

111

Apoplastic Sugars, Fructans, Fructan Exohydrolase, and Invertase in Winter Oat: Responses to Second-Phase Cold Hardening  

PubMed Central

Changes in apoplastic carbohydrate concentrations and activities of carbohydrate-degrading enzymes were determined in crown tissues of oat (Avena sativa L., cv Wintok) during cold hardening. During second-phase hardening (?3°C for 3 d) levels of fructan, sucrose, glucose, and fructose in the apoplast increased significantly above that in nonhardened and first-phase-hardened plants. The extent of the increase in apoplastic fructan during second-phase hardening varied with the degree of fructan polymerization (DP) (e.g. DP3 and DP4 increased to a greater extent than DP7 and DP > 7). Activities of invertase and fructan exohydrolase in the crown apoplast increased approximately 4-fold over nonhardened and first-phase-hardened plants. Apoplastic fluid extracted from nonhardened, first-phase-hardened, and second-phase-hardened crown tissues had low levels, of symplastic contamination, as determined by malate dehydrogenase activity. The significance of these results in relation to increases in freezing tolerance from second-phase hardening is discussed.

Livingston, David P.; Henson, Cynthia A.

1998-01-01

112

A Comparative Spin-Label Study of Isolated Plasma Membranes and Plasma Membranes of Whole Cells and Protoplasts from Cold-Hardened and Nonhardened Winter Rye  

PubMed Central

Lipid-lipid and lipid-protein interactions in the plasma membranes of whole cells and protoplasts and an isolated plasma membrane fraction from winter rye (Secale cereale L. cv Puma) have been studied by spin labeling. Spectra were recorded between ?40°C and 40°C using the freely diffusing spin-label, 16-doxyl stearic acid, as a midbilayer membrane probe. The probe was reduced by the whole cells and protoplasts and reoxidized by external potassium ferricyanide. The reoxidized probe was assumed to be localized in the plasma membrane. The spectra consisted of the superposition of a narrow and a broad component indicating that both fluid and immobilized lipids were present in the plasma membrane. The two components were separated by digital subtraction of the immobilized component. Temperature profiles of the membranes were developed using the percentage of immobilized lipid present at each temperature and the separation between the outermost hyperfine lines for the fluid lipid component. Lipid immobilization was attributed to lipid-protein interactions, lipid-cell wall interactions, and temperature-induced lipid phase transitions to the gel-state. Temperature profiles were compared for both cold-hardened and nonhardened protoplasts, plasma membranes, and plasma membrane lipids, respectively. Although cold-hardening extended the range of lipid fluidity by 5°C, it had no effect on lipid-protein interactions or activation energies of lipid mobility. Differences were found, however, between the temperature profiles for the different samples, suggesting that alterations in the plasma membrane occurred as a consequence of the isolation methods used.

Windle, John J.

1988-01-01

113

Bio-Optical Properties and Ocean Color Algorithms for Coastal Waters Influenced by the Mississippi River During a Cold Front Passage  

NASA Technical Reports Server (NTRS)

During the passage of a cold front in March 2002, bio-optical properties examined in coastal waters impacted by the Mississippi River indicated westward advective flows and increasing river discharge containing a larger nonalgal particle content contributed significantly to surface optical variability. A comparison of seasonal data from three cruises indicated spectral models of absorption and scattering to be generally consistent with other coastal environments, while their parameterization in terms of chlorophyll a concentration (Chl) showed seasonal variability. The exponential slope of the colored dissolved organic matter (CDOM) averaged 0.0161 plus or minus 0.00054 per nanometer, and for nonalgal absorption it averaged 0.011 per nanometer with deviations from general trends observed due to anomalous water properties. Although the phytoplankton specific absorption coefficients varied over a wide range (0.02 to 0.1 square meters (mg Chl) sup -1)) being higher in offshore surface waters, values of phytoplankton absorption spectra at the SeaWiFS wavebands were highly correlated to modeled values. The normalized scattering spectral shapes and the mean spectrum were in agreement to observations in other coastal waters, while the backscattering ratios were on average lower in phytoplankton dominated surface waters (0.0101 plus or minus 0.002) and higher in near-bottom waters (0.0191 plus or minus 0.0045) with low Chl. Average percent differences in remote sensing reflectance R (sub rs) derived form modeled and in-eater radiometric measurements were highest in the blue wavebands (52%) and at sampling stations with a ore stratified water column. Estimates of Chl and CDOM absorption derived from SeaWiFS images generated using regional empirical algorithms were highly correlated to in situ data.

D'Sa Eurico J.; Miller, Richard L.; DelCastillo, Carlos

2006-01-01

114

KELVIN-HELMHOLTZ INSTABILITIES AT THE SLOSHING COLD FRONTS IN THE VIRGO CLUSTER AS A MEASURE FOR THE EFFECTIVE INTRACLUSTER MEDIUM VISCOSITY  

SciTech Connect

Sloshing cold fronts (CFs) arise from minor merger triggered gas sloshing. Their detailed structure depends on the properties of the intracluster medium (ICM): hydrodynamical simulations predict the CFs to be distorted by Kelvin-Helmholtz instabilities (KHIs), but aligned magnetic fields, viscosity, or thermal conduction can suppress the KHIs. Thus, observing the detailed structure of sloshing CFs can be used to constrain these ICM properties. Both smooth and distorted sloshing CFs have been observed, indicating that the KHI is suppressed in some clusters, but not in all. Consequently, we need to address at least some sloshing clusters individually before drawing general conclusions about the ICM properties. We present the first detailed attempt to constrain the ICM properties in a specific cluster from the structure of its sloshing CF. Proximity and brightness make the Virgo Cluster an ideal target. We combine observations and Virgo-specific hydrodynamical sloshing simulations. Here, we focus on a Spitzer-like temperature-dependent viscosity as a mechanism to suppress the KHI, but discuss the alternative mechanisms in detail. We identify the CF at 90 kpc north and northeast of the Virgo center as the best location in the cluster to observe a possible KHI suppression. For viscosities {approx}> 10% of the Spitzer value KHIs at this CF are suppressed. We describe in detail the observable signatures at low and high viscosities, i.e., in the presence or the absence of KHIs. We find indications for a low ICM viscosity in archival XMM-Newton data and demonstrate the detectability of the predicted features in deep Chandra observations.

Roediger, E. [Hamburger Sternwarte, Universitaet Hamburg, Gojensbergsweg 112, D-21029 Hamburg (Germany)] [Hamburger Sternwarte, Universitaet Hamburg, Gojensbergsweg 112, D-21029 Hamburg (Germany); Kraft, R. P.; Forman, W. R.; Nulsen, P. E. J. [Harvard/Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard/Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Churazov, E., E-mail: eroediger@hs.uni-hamburg.de [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

2013-02-10

115

Kelvin-Helmholtz Instabilities at the Sloshing Cold Fronts in the Virgo Cluster as a Measure for the Effective Intracluster Medium Viscosity  

NASA Astrophysics Data System (ADS)

Sloshing cold fronts (CFs) arise from minor merger triggered gas sloshing. Their detailed structure depends on the properties of the intracluster medium (ICM): hydrodynamical simulations predict the CFs to be distorted by Kelvin-Helmholtz instabilities (KHIs), but aligned magnetic fields, viscosity, or thermal conduction can suppress the KHIs. Thus, observing the detailed structure of sloshing CFs can be used to constrain these ICM properties. Both smooth and distorted sloshing CFs have been observed, indicating that the KHI is suppressed in some clusters, but not in all. Consequently, we need to address at least some sloshing clusters individually before drawing general conclusions about the ICM properties. We present the first detailed attempt to constrain the ICM properties in a specific cluster from the structure of its sloshing CF. Proximity and brightness make the Virgo Cluster an ideal target. We combine observations and Virgo-specific hydrodynamical sloshing simulations. Here, we focus on a Spitzer-like temperature-dependent viscosity as a mechanism to suppress the KHI, but discuss the alternative mechanisms in detail. We identify the CF at 90 kpc north and northeast of the Virgo center as the best location in the cluster to observe a possible KHI suppression. For viscosities >~ 10% of the Spitzer value KHIs at this CF are suppressed. We describe in detail the observable signatures at low and high viscosities, i.e., in the presence or the absence of KHIs. We find indications for a low ICM viscosity in archival XMM-Newton data and demonstrate the detectability of the predicted features in deep Chandra observations.

Roediger, E.; Kraft, R. P.; Forman, W. R.; Nulsen, P. E. J.; Churazov, E.

2013-02-01

116

Mammals in Winter.  

ERIC Educational Resources Information Center

Mammals that tolerate the winter cold and stay active all year exploit the harsh northern climate to their advantage. By simple experiments and observation you can better understand their adaptations which include furry bodies, snowshoe feet, extra blubber, light coloration, and strategically distributed food caches. (JHZ)

Wapner, Suzanne

1985-01-01

117

Warm winter spells in the Swiss Alps: Strong heat waves in a cold season? A study focusing on climate observations at the Saentis high mountain site  

Microsoft Academic Search

Investigations conducted for several Swiss mountain climatological sites, and in particular the Saentis high mountain site at 2,500 m above sea level, show that positive temperature anomalies during the winter season currently exceed those of all other seasons. These ``heat waves'' exhibit daily maximum temperature anomalies sometimes in excess of 16°C, and are observed to have increased substantially since the

Martin Beniston

2005-01-01

118

Surviving the Cold  

MedlinePLUS Videos and Cool Tools

... HealthDay January 31, 2014 Related MedlinePlus Pages Frostbite Hypothermia Winter Weather Emergencies Transcript Millions of Americans are ... dangerous cold-related complications such as frostbite or hypothermia. Luckily, protection can be found in just a ...

119

Stationary fronts prolong bad weather  

NSDL National Science Digital Library

These simple animated GIF's are activated with cursor rollover and picture the standoff when neither the warm front nor the cold front is advancing. On a weather map the stationary front is marked by alternating triangles and half circles with the triangles pointing toward the warm air and the circles pointing toward the cooler air. The overriding of warm air on the cooler air can bring several days of cloudy, inclement weather. While the front appears to touch the ground the actual boundary between air masses can be thousands of feet aloft and hundreds of miles away.

Herne, John; Today, Usa

120

Warm winter spells in the Swiss Alps: Strong heat waves in a cold season? A study focusing on climate observations at the Saentis high mountain site  

NASA Astrophysics Data System (ADS)

Investigations conducted for several Swiss mountain climatological sites, and in particular the Saentis high mountain site at 2,500 m above sea level, show that positive temperature anomalies during the winter season currently exceed those of all other seasons. These ``heat waves'' exhibit daily maximum temperature anomalies sometimes in excess of 16°C, and are observed to have increased substantially since the late 1960s. These events are related to the North Atlantic Oscillation (NAO) that exerts significant controls on snow cover and surface-atmosphere temperature feedbacks in the alpine region. A glimpse to the future is provided for the period 2071-2100, based on regional climate model simulations which suggest that warm winter spells may increase by 30%. The impacts of such events, particularly in terms of snow and water availability and the mountain economies that depend on these resources, need to be incorporated into future strategic resource and economic planning in the Alps.

Beniston, Martin

2005-01-01

121

Winter Storms  

NSDL National Science Digital Library

This site offers general background about winter storms as well as interactive activities to teach visitors about these storms. It also offers a teacher's guide to using this site and links to other weather-related pages. There are four main topics: All About Winter Storms, Interactive Weather Maker, Interactive Winter Storm Timeline, and Ask Our Winter Storm Expert. All About Winter Storms gives general background information an a glossary of weather terms. The Weather Maker offers students a chance to control the weather through a simulation in which they affect the weather by changing variables such as humidity, equatorward temperature, and polarward temperature. The Storm Timeline offers students a chance to move up and down the timeline to learn about past winter storms. In Ask the Expert, students can email their questions to a winter storm expert and have them answered. This section also gives a brief biography of the expert.

1996-01-01

122

Fronts and frontogenesis as revealed by high time resolution data  

NASA Technical Reports Server (NTRS)

Upper air sounding are used to examine a cold front of average intensity. Vertical cross sections of potential temperature and wind, and horizontal analyses were compared and adjusted for consistency. These analyses were then used to study the evolution of the front, found to consist of a complex system of fronts occurring at all levels of the troposphere. Low level fronts were strongest at the surface and rapidly weakened with height. Fronts in the midddle troposphere were much more intense. The warm air ahead of the fronts was nearly barotropic, while the cold air behind was baroclinic through deep layers. A deep mixed layer was observed to grow in this cold air.

Frank, A. E.; Barber, D. A.

1977-01-01

123

The Cold European Winter of 2005–2006 Assisted the Spread and Persistence of H5N1 Influenza Virus in Wild Birds  

Microsoft Academic Search

In January 2006, a major cold spell affected Europe, coinciding with an increase of H5N1 influenza virus detected in wild\\u000a birds, mostly dead mute swans, starting along the River Danube and the Mediterranean coast line. Subsequently H5N1 detections\\u000a in wild birds were concentrated in central and western parts of Europe, reaching a peak in mid February. We tested the hypothesis

Daniela Ottaviani; S. de la Rocque; S. Khomenko; M. Gilbert; S. H. Newman; B. Roche; K. Schwabenbauer; J. Pinto; T. P. Robinson; J. Slingenbergh

2010-01-01

124

Winter Weather  

MedlinePLUS

... of cold stress include: trench foot, frostbite, and hypothermia. For more information, see OSHA's Cold Stress Safety ... First Aid Follow the recommendations described below for hypothermia. Protect the frostbitten area, e.g., by wrapping ...

125

Surviving Winter  

NSDL National Science Digital Library

In this lesson designed to enhance literacy skills, students learn about the varied physical and behavioral adaptations that animals rely on to help them survive changing environmental conditions, such as the arrival of winter.

Foundation, Wgbh E.

2010-12-13

126

Winter Weather  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Bellows, Mrs.

2009-09-28

127

Winter storms  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Brieanne

2011-02-14

128

The January 2009 anomalous precipitation associated with the “Tail-end of the Cold Front” weather system in Northern and Eastern Mindanao (Philippines): Natural hazards, impacts and risk reductions  

NASA Astrophysics Data System (ADS)

In the first half of January 2009, the southern Philippine island of Mindanao was overwhelmed by numerous natural disasters caused by the passage of the tail-end of the cold front. This otherwise ordinary weather condition was accompanied by unusually heavy precipitation sustained over a period of several days. This triggered numerous landslides and caused many drainage systems to swell, flooding huge tracts of low lying areas that have not experienced similar events in the recent past. Many communities were caught unprepared for the calamity. The amount and extent of damage reflect both the magnitude of the natural disaster itself and the community's nominal level of disaster-preparedness. In view of the increasing atmospheric moisture levels and the likelihood that global warming will affect the weather patterns, there is a possibility that similar weather disturbances can become more frequent. Therefore, there is an urgent need for disaster risk management programs to be developed or enhanced at the local community level especially in areas most vulnerable to weather-related natural hazards, in light of changing global climatic patterns.

Faustino-Eslava, Decibel V.; Yumul, Graciano P., Jr.; Servando, Nathaniel T.; Dimalanta, Carla B.

2011-03-01

129

Are summit metabolism and thermogenic endurance correlated in winter-acclimatized passerine birds?  

Microsoft Academic Search

Small birds exhibiting marked winter improvement of cold tolerance also show elevated summit metabolic rates (maximum cold-induced metabolic rate) in winter relative to summer. However, relatively large increases in cold tolerance can occur with only minor increments of maximum cold-induced metabolic rate and geographic variation in cold tolerance is not always positively correlated with variation in maximum cold-induced metabolic rate.

David L. Swanson

2001-01-01

130

Ponds Freeze in Winter -- Why Doesn't the Ocean?  

NSDL National Science Digital Library

In this activity, learners explore how salt water freezes in comparison to fresh water. Use this experiment to consider how pond animals survive cold winters in comparison to animals that live in the ocean. This resource includes information about freezing points as well as examples of how different animals respond to the winter cold.

Aquarium, New E.

2011-01-01

131

Winter Workshop.  

ERIC Educational Resources Information Center

Materials on 11 topics presented at a winter workshop for Quebec outdoor educators have been compiled into this booklet. Action story, instant replay, shoe factory, sound and action, and find an object to fit the description are described and recommended as group dynamic activities. Directions for five games (Superlative Selection; Data…

Council of Outdoor Educators of Quebec, Montreal.

132

Winter Games.  

ERIC Educational Resources Information Center

Educators may find activities for indoor and outdoor winter programs in the games of the traditional Eskimo. These games are dominated by few-step operations and low level structural organization. For the most part they are quickly organized, begun, terminated, and ready to be recommenced. All types of games can be found, including quiet ones,…

Tarbuth, Lawson, Comp.

133

Observation of dust emission and transport over Iraq and northwest Iran associated with winter Shamal  

NASA Astrophysics Data System (ADS)

Dynamical processes leading to dust emission over Syria and Iraq, in response to a strong winter Shamal event as well as the subsequent transport of dust over Iraq and northwest Iran, are analyzed on the basis of a case study (22-23 February 2010) using a suite of ground-based and space-borne remote sensing platforms together with modeling tools. Surface measurements on 22 February show a sharp reduction in horizontal visibility over Iraq occurring shortly after the passage of a cold front (behind which the northwesterly Shamal winds were blowing) and that visibilities could be as low as 1 km on average for one to two days in the wake of the front. The impact of the southwesterly Kaus winds blowing ahead (east) of the Shamal winds on dust emission over Iraq is also highlighted. Unlike what is observed over Iraq, low near-surface horizontal visibilities (less than 1 km) over northwest Iran are observed well after the passage of the cold front on 23 February, generally in the hours following sunrise. Ground-based lidar measurements acquired in Zanjan show that, in the wake of the front, dust from Syria/Iraq was transported in an elevated 1 to 1.5 km thick plume separated from the surface during the night/morning of February. After sunrise, strong turbulence in the developing convective boundary layer led to mixing of the dust into the boundary layer and in turn to a sharp reduction of the horizontal visibility in Zanjan. The timing of the reduction of surface horizontal visibility in other stations over northwest Iran (Tabriz, Qom and Tehran) is consistent with the downward mixing of dust in the PBL just after sunset, as evidenced in Zanjan. This study shades new light on the processes responsible for dust emission and transport over Iraq and northwest Iran in connection with winter Shamal events. Enhanced knowledge of these processes is key for improving dust forecasts in this region.

Flamant, C.; Abdi Vishkaee, F.; Cuesta, J.; Khalesifard, H.; Oolman, L.; Flamant, P.

2012-04-01

134

Dust transport over Iraq and northwest Iran associated with winter Shamal: A case study  

NASA Astrophysics Data System (ADS)

Dynamical processes leading to dust emission over Syria and Iraq, in response to a strong winter Shamal event as well as the subsequent transport of dust over Iraq and northwest Iran, are analyzed on the basis of a case study (22-23 February 2010) using a suite of ground-based and spaceborne remote sensing platforms together with modeling tools. Surface measurements on 22 February show a sharp reduction in horizontal visibility over Iraq occurring shortly after the passage of a cold front (behind which the northwesterly Shamal winds were blowing) and that visibilities could be as low as 1 km on average for 1-2 days in the wake of the front. The impact of the southwesterly Kaus winds blowing ahead (east) of the Shamal winds on dust emission over Iraq is also highlighted. Unlike what is observed over Iraq, low near-surface horizontal visibilities (<1 km) over northwest Iran are observed well after the passage of the cold front on 23 February, generally in the hours following sunrise. Ground-based lidar measurements acquired in Zanjan show that, in the wake of the front, dust from Syria/Iraq was transported in an elevated 1 to 1.5 km thick plume separated from the surface during the night/morning of 23 February. After sunrise, strong turbulence in the developing convective boundary layer led to mixing of the dust into the boundary layer and in turn to a sharp reduction of the horizontal visibility in Zanjan. The timing of the reduction of surface horizontal visibility in other stations over northwest Iran (Tabriz, Qom, and Tehran) is consistent with the downward mixing of dust in the planetary boundary layer just after sunset, as evidenced in Zanjan. This study sheds new light on the processes responsible for dust emission and transport over Iraq and northwest Iran in connection with winter Shamal events. Enhanced knowledge of these processes is key for improving dust forecasts in this region.

Abdi Vishkaee, Farhad; Flamant, Cyrille; Cuesta, Juan; Oolman, Larry; Flamant, Pierre; Khalesifard, Hamid R.

2012-02-01

135

Distribution of Alewives in Southeastern Lake Ontario in Autumn and Winter: A Clue to Winter Mortalities  

Microsoft Academic Search

Alewives Alosa pseudoharengus in the Great Lakes are thought to avoid extreme cold in winter by moving to deep water where the temperature is usually highest because of inverse thermal stratification. Information collected in Lake Ontario during autumn and winter 1981–1984 with an echo sounder and bottom and midwater trawls indicated that many alewives remained at depths above 110 m,

Roger A. Bergstedt; Robert OGorman

1989-01-01

136

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. Does increased humidity usually increase of decrease your chances for rain? 4. What happens when there is ...

Sarah

2009-09-28

137

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. How can you get them to stop, when they are blowing? 3. What tends happens when there is a large difference between the temperatures? 4. What happens when there ...

Liz, Miss

2010-05-26

138

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the ...

Schilling, Ashley

2010-05-26

139

Winter Storms  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Sappa, Mr.

2010-05-26

140

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? ...

Smith, Miss

2010-09-27

141

Titan's Winter Polar Vortex  

NASA Technical Reports Server (NTRS)

Titan's atmosphere has provided an interesting study in contrasts and similarities with Earth's. While both have N$_2$ as the dominant constituent and comparable surface pressures $\\sim1$ bar, Titan's next most abundant molecule is CH$_4$, not O$_2$, and the dissociative breakup of CH$_4$ and N$_2$ by sunlight and electron impact leads to a suite of hydrocarbons and nitriles, and ultimately the photochemical smog that enshrouds the moon. In addition, with a 15.95-day period, Titan is a slow rotator compared to Earth. While the mean zonal terrestrial winds are geostrophic, Titan's are mostly cyclostrophic, whipping around the moon in as little as 1 day. Despite the different dynamical regime, Titan's winter stratosphere exhibits several characteristics that should be familiar to terrestrial meteorologists. The cold winter pole near the 1 -mbar level is circumscribed by strong winds (up to 190 m/s) that act as a barrier to mixing with airmasses at lower latitudes. There is evidence of enhancement of several organic species over the winter pole, indicating subsidence. The adiabatic heating associated with this subsidence gives rise to a warm anomaly at the 0.01-mbar level, raising the stratopause two scale heights above its location at equatorial latitudes. Condensate ices have been detected in Titan's lower stratosphere within the winter polar vortex from infrared spectra. Although not always unambiguously identified, their spatial distribution exhibits a sharp gradient, decreasing precipitously across the vortex away from the winter pole. The interesting question of whether there is important heterogeneous chemistry occurring within the polar vortex, analogous to that occurring in the terrestrial polar stratospheric clouds in the ozone holes, has not been addressed. The breakup of Titan's winter polar vortex has not yet been observed. On Earth, the polar vortex is nonlinearly disrupted by interaction with large-amplitude planetary waves. Large-scale waves have not been identified in Titan's atmosphere, so the decay of its polar vortex may be more gradual than on Earth. Observations from an extended Cassini mission into late northern spring should provide critical data indicating whether the vortex goes away with a bang or just fades away.

Flasar, F.M.; Achterberg, R.K.; Schinder, P.J.

2008-01-01

142

Distribution of alewives in southeastern Lake Ontario in autumn and winter: a clue to winter mortalities  

USGS Publications Warehouse

Alewives Alosa pseudoharengus in the Great Lakes are thought to avoid extreme cold in winter by moving to deep water where the temperature is usually highest because of inverse thermal stratification. Information collected in Lake Ontario during autumn and winter 1981-1984 with an echo sounder and bottom and midwater trawls indicated that many alewives remained at depths above 110 m, regardless of water temperature. Alewives in the Great Lakes that did not descend to greater depths would be exposed to potentially lethal temperatures during cold winters.

Bergstedt, Roger A.; O'Gorman, Robert

1989-01-01

143

Winter snow  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. 1. What do you already know about the weather? 2. How does the weather effect you daily? Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What ...

Peterson, Lori

2009-09-28

144

Radiative magnetized thermal conduction fronts  

NASA Technical Reports Server (NTRS)

The evolution of plane-parallel magnetized thermal conduction fronts in the interstellar medium (ISM) was studied. Separating the coronal ISM phase and interstellar clouds, these fronts have been thought to be the site of the intermediate-temperature regions whose presence was inferred from O VI absorption-line studies. The front evolution was followed numerically, starting from the initial discontinuous temperature distribution between the hot and cold medium, and ending in the final cooling stage of the hot medium. It was found that, for the typical ISM pressure of 4000 K/cu cm and the hot medium temperature of 10 to the 6th K, the transition from evaporation to condensation in a nonmagnetized front occurs when the front thickness is 15 pc. This thickness is a factor of 5 smaller than previously estimated. The O VI column densities in both evaporative and condensation stages agree with observations if the initial hot medium temperature Th exceeds 750,000 K. Condensing conduction fronts give better agreement with observed O VI line profiles because of lower gas temperatures.

Borkowski, Kazimierz J.; Balbus, Steven A.; Fristrom, Carl C.

1990-01-01

145

Relating Global Precipitation to Atmospheric Fronts  

NASA Astrophysics Data System (ADS)

Atmospheric fronts are important for the day-to-day variability of weather in the midlatitudes, particularly during winter when extratropical storm-tracks are at their maximum intensity. Fronts are often associated with heavy rain, and strongly affect the local space-time distribution of rainfall. Although global climate models should be expected to represent the baroclinic systems within which the fronts are embedded, the fronts themselves and precipitation processes within them are of much smaller scale. As a consequence, models with the typical horizontal resolution of contemporary climate models do not necessarily accurately capture these features. A recently developed objective front identification method applied to reanalysis data is combined with global rainfall data to investigate how precipitation and extremes of precipitation around the globe are associated with atmospheric fronts. Having established the observed distribution of fronts and their role in producing precipitation and extremes, the occurrence of fronts and the associated precipitation can then be evaluated in state-of-the-art climate models. This provides a process-oriented method of model evaluation where the errors in the model can be decomposed into contributions from errors in front frequency and errors in frontal and non-frontal precipitation intensity. Finally, how fronts and their associated precipitation, may change in the future, especially the extremes, can be investigated.

Catto, J. L.; Jakob, C.; Nicholls, N.

2012-12-01

146

Some characteristics of the surface boundary layer of a strong cold air process over southern China  

NASA Astrophysics Data System (ADS)

In southern China, cold air is a common weather process during the winter season; it can cause strong wind, sharp temperature decreases, and even the snow or freezing rain events. However, the features of the atmospheric boundary layer during cold air passage are not clearly understood due to the lack of comprehensive observation data, especially regarding turbulence. In this study, four-layer gradient meteorological observation data and one-layer, 10-Hz ultrasonic anemometer-thermometer monitoring data from the northern side of Poyang Lake were employed to study the main features of the surface boundary layer during a strong cold-air passage over southern China. The results show that, with the passage of a cold air front, the wind speed exhibits low-frequency variations and that the wind systematically descends. During the strong wind period, the wind speed increases with height in the surface layer. Regular gust packets are superimposed on the basic strong wind flow. Before the passage of cold air, the wind gusts exhibit a coherent structure. The wind and turbulent momentum fluxes are small, although the gusty wind momentum flux is slightly larger than the turbulent momentum flux. However, during the invasion of cold air, both the gusty wind and turbulent momentum fluxes increase rapidly with wind speed, and the turbulent momentum flux is larger than the gusty wind momentum flux during the strong wind period. After the cold air invasion, this structure almost disappears.

Liu, Ximing; Cheng, Xueling; Wu, Qiong; Fu, Minning; Zeng, Qingcun

2013-01-01

147

`Thermohaline front' off the east coast of India and its generating mechanism  

NASA Astrophysics Data System (ADS)

Physical oceanography measurements reveal a strong salinity (0.18 psu km-1) and temperature (0.07 °C km-1) front off the east coast of India in December 1997. T-S diagrams suggest lateral mixing between the fresh water at the coast and the ambient warmer, saltier water. This front seems to be the result of southward advection of fresh and cool water, formed in the northern Bay of Bengal during the monsoon, by the East Indian Coastal Current, as suggested by the large-scale salinity structure in the SODA re-analysis and the anti-cyclonic gyre in the northwestern Bay of Bengal during winter. The data further reveals an offshore front in January, which appears to be the result of a meso-scale re-circulation around an eddy, bringing cold and freshwater from the northern Bay of Bengal further away from the shore. Our cruise data hence illustrates that very strong salinity fronts can appear in the Bay of Bengal after the monsoon, as a result of intense coastal circulation and stirring by eddies.

Hareesh Kumar, Panangattu Viswanathan; Mathew, Basil; Ramesh Kumar, Madathiparambil Ranganatha; Raghunadha Rao, Akula; Jagadeesh, Puvvala Surya Venkata; Radhakrishnan, Kalarickal Gopalan; Shyni, Thiyyadi Nandakumar

2013-12-01

148

Cold Sores  

MedlinePLUS

... directly to your desktop! more... What Are Cold Sores? Article Chapters What Are Cold Sores? Cold Sore ... 2012 Previous Next Related Articles: Canker and Cold Sores Aloe Vera May Help Relieve Mouth Sores Canker ...

149

Ocean fronts trigger high latitude phytoplankton blooms  

NASA Astrophysics Data System (ADS)

Density fronts are ubiquitous features of the upper ocean. Here, numerical simulations show that restratification at fronts inhibits vertical mixing, triggering phytoplankton blooms in low-light conditions. The stability of the water column at fronts is set by a competition between frontal instabilities, which restratify the upper ocean, and turbulent mixing, which acts to destroy this stratification. Recent studies have found that frontal instabilities can restratify the upper ocean, even in the presence of strong surface cooling and destabilizing winds. During winter at high latitudes, primary production by phytoplankton is generally limited by low ambient light levels and deep turbulent mixing. When the turbulent mixing, inhibited by frontal restratification, becomes smaller than a ‘critical turbulence’ threshold, a phytoplankton bloom can develop. The finding that fronts can trigger phytoplankton blooms by reducing mixing, provides an explanation for satellite observations of high chlorophyll concentrations at high latitude fronts.

Taylor, J. R.; Ferrari, R.

2011-12-01

150

Spatiotemporal variability of thermal front features in the Baltic Sea 2010-2011  

NASA Astrophysics Data System (ADS)

Regions of the formation of the thermal front in the Baltic Sea (a direct manifestation of the lacustrine thermal bar), and its specific features, were analyzed on the basis of subsurface temperature and salinity. Data were obtained from 25 horizontal tows along sections in the southern and central parts of the Baltic Sea during spring 2010 and autumn/winter 2010/2011. The width of the front was approximately 5-30 km, and the front lifetime was 1.5 months. Horizontal temperature ranged from 0.7 to 2.5°C; thus, the temperature gradient was one- to twofold larger than the long-term monthly mean equivalent. Analysis of hourly temperature and salinity data from the Arkona basin and at the Darss Sill, obtained at 2 m depth, indicated that the surface temperature increased during the transition through temperatures of maximum density at a rate of approximately 0.01-0.02°C/h between 3-5 days; which is 1.4- to 5-fold higher than values before and after this period. The thermal front simultaneously propagated along the main sea axis (due to the significant salinity and buoyancy flux variations from south to north), and from the shallow parts towards the deep parts of the Baltic Sea. Therefore, the horizontal advection of the cold/warm waters clearly contributes to the speed increase of the thermal front at the end of the respective season. The speed of the thermal front propagation from south to north was approximately 28 km/day at the end of the spring period of 2010 (based on field data). This was considerably higher in comparison with the typical values of the lacustrine thermal bar speeds; however, it accords with estimates for a basin with depth/salinity horizontal variation.

Demchenko, N. Yu.; Chubarenko, I. P.

2012-11-01

151

Front Resolving Observational Network with Telemetry (FRONT).  

National Technical Information Service (NTIS)

The Front Resolving Observational Network with Telemetry (FRONT) experiment is designed to evaluate the feasibility of making useful coastal ocean forecasts with a coarse array of instruments that telemeter data in near- real time for use in an assimilati...

C. Edwards D. Codiga D. Hebert D. Ullman J. O'Donnell

2002-01-01

152

Modeling Experiment for winter circulation in Calcasieu Lake, LA  

NASA Astrophysics Data System (ADS)

Cold-front-induced water level oscillation and associated salinity distributions in Calcasieu Lake, southwestern Louisiana, were examined using a numerical model and field observations. The cold-front-induced flushing under the influence of Calcasieu River runoff, local wind stress, and tide determine the hydrodynamic features of Calcasieu Lake in winter. Based on observations carried out from Dec. 20, 2011 to Feb. 1, 2012, numerical model experiments with different conditions were conducted. The model predicts a depth-averaged flow pattern over the domain consisting of the shallow Calcasieu Lake and deep Ship Channel. A clockwise circulation in Calcasieu Lake coupled with the Ship Channel and a counterclockwise circulation in West Cove were demonstrated. It is through the shallow shoals, not the deep Ship Channel, that water from Calcasieu Lake flows into the ocean. This circulation pattern is typical of estuaries with shallow water influenced by river discharge and with weak tidally-induced motion. Both the observations and the model indicate saltwater intrusion along the Ship Channel into the northern lake. Salinity gradient induced baroclinic pressure gradient and Coriolis force also play relatively important roles in the circulation of Calcasieu Lake. Local wind stress played a negative role in the saltwater intrusion along the Ship Channel except under an east wind. The depth of the Ship Channel is a key factor influencing saltwater intrusion, the deeper the Channel, the more saltwater intrusion. Saltwater intrusion along the Ship Channel increases the magnitude of the Lake circulation and moderates salinity changes in adjacent wetlands caused by heavy rainfall. Circulation indicated by sum of water mass flux at transects Modeling experiment schedule

Lin, J.; Li, C.; Boswell, K.; Kimball, M.; Rozas, L.; Broussard, L.; Zhang, F.

2013-12-01

153

Pressure transient method for front tracking  

SciTech Connect

A pressure transient technique for tracking the advance of cold water fronts during water flooding and goethermal injection operations has been developed. The technique is based on the concept that the steady state pressure buildup in the reservoir region inside the front can be calculated by a fluid skin factor. By analyzing successive pressure falloff tests, the advance of the front in the reservoir can be monitored. The validity of the methods is demonstrated by application to three numerically simulated data sets, a nonisothermal step-rate injection test, a series of pressure falloffs in a multilayered reservoir, and a series of pressure falloff tests in a water flooded oil reservoir.

Benson, S.M.; Bodvarsson, G.S.

1983-08-01

154

Measurements of Chlorine Partitioning in the Winter Arctic Stratosphere  

NASA Technical Reports Server (NTRS)

Under the extremely cold conditions in the polar winter stratosphere, heterogeneous reactions involving HCl and CIONO(sub 2) on the surfaces of polar stratospheric cloud particles can release large amounts of reactive chlorine from these reservoirs leading to rapid chemical loss of ozone in the Arctic lower stratosphere during late winter and early spring.

Stachnik, R.; Salawitch, R.; Engel, A.; Schmidt, U.

1999-01-01

155

Optically thick ablation fronts. [in interstellar medium  

NASA Technical Reports Server (NTRS)

The physical characteristics of optically thick ablation fronts such as interstellar clouds are analyzed. Attention is given to cold clumps in both planar and spherical geometries and modifications caused by accelerations in a gravitational field or by evaporation of the clumps when encountered hot gas. The effects of ablation on the appearance of the Rayleigh-Taylor instability are examined in both linear and nonlinear regimes. The results of the calculations are applied to the astrophysical phenomena of cold clumps immersed in a supersonic flow, optically thick jets, and ablation in stellar envelopes. Evaporation in an optically thick front is projected to be orders of magnitude larger than evaporation in electron-conduction fronts in optically thin conditions. The optically thick processes could then be useful for modeling flows from, e.g., newly formed stars and active galactic nuclei.

Konigl, A.

1984-01-01

156

Cold sea survival.  

NASA Technical Reports Server (NTRS)

Two prototype three-man life rafts were evaluated during the winter months in Arctic waters off Kodiak Island, Alaska, to assess potential survival problems and determine tolerance limits. Each raft incorporated thermal characteristics specifically designed for cold water. Water and air temperatures varied from 0 to +2 C and -5 to +4 C respectively. All subjects were removed upon reaching subjective tolerance. The results showed that none of the clothing assemblies was adequate to maintain a person in comfort even with dry boarding. No significant biochemical shifts in the blood or urine were found. The TUL raft was found to be superior in its thermal characteristics and afforded better subject protection. General tolerance for cold water immersion, wet and dry, and cold water raft exposures are depicted graphically, based on previously reported data.

Veghte, J. H.

1972-01-01

157

Cold tolerance and homeoviscous adaptation in freshwater alewives ( Alosa pseudoharengus )  

Microsoft Academic Search

During cold winters, freshwater populations of alewives (Alosa pseudoharengus) are prone to massive die-offs, the physiological causes of which are poorly understood. We analyzed fatty acid composition\\u000a before and after a laboratory cold challenge to examine the potential loss of cell membrane fluidity as a factor in winter\\u000a mortality of these fish. Fish that died during the cold challenge displayed

Randal J. Snyder; Todd M. Hennessey

2003-01-01

158

Science of Winter  

NSDL National Science Digital Library

Science of Winter is a collection of activities, lessons, interactives, images, or other content illustrating or demonstrating scientific aspects of winter weather, conditions, processes, or phenomena, appropriate for middle school, informal education, and general audiences.

2009-07-30

159

Nutrition Frontiers - Winter 2010  

Cancer.gov

Nutrition Frontiers - Winter 2010 Winter 2010 Volume 1, Issue 1 Dear Colleague, Welcome to the first issue of Nutrition Frontiers, a quarterly newsletter from the Nutritional Science Research Group (NSRG), Division of Cancer Prevention, NCI. In this

160

Act now to avoid winter deaths.  

PubMed

Essential facts [Figure: see text] Cold weather has a direct effect on the number of people experiencing heart attacks, stroke, respiratory disease and flu. According to the Office for National Statistics, an estimated 31,100 excess winter deaths occurred in England and Wales in 2012/13 - a rise of 29 per cent compared with the previous year. Of these people, 25,600 were aged 75 or above. PMID:25052647

2014-07-23

161

Dehydration in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

Recent work has shown that limited amounts of tropospheric air can penetrate as much as 1 km into the middleworld stratosphere during the arctic winter. This, coupled with temperatures that are cold enough to produce saturation mixing ratios of less than 5 ppmv at the tropopause, results in stratospheric cloud formation and upper tropospheric dehydration. Even though these "cold outbreaks" occupy only a small portion of the area in the arctic (1-2%), their importance is magnified by an order of magnitude because of the air flow through them. This is reinforced by evidence of progressive drying through the winter measured during SOLVE-1. The significance of this process lies in its effect on the upper tropospheric water content of the middle and high latitude tropopause region, which plays an important role in regulating the earth's radiative balance. There appears to be significant year-to-year variability in the incidence of the cold outbreaks. This work has two parts. First, we describe case studies of dehydration taken from the SOLVE and SOLVE2 aircraft sampling missions during the Arctic winters of 2000 and 2003 respectively. Trajectory based microphysical modeling is employed to examine the sensitivity of the dehydration to microphysical parameters and the nature of sub-grid scale temperature fluctuations. We then examine the year-to-year variations in potential dehydration using a trajectory climatology.

Pfister, Leonhard; Jensen, Eric; Podolske, James; Selkirk, Henry; Anderson, Bruce; Avery, Melody; Diskin. Glenn

2004-01-01

162

Clouds in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

Water vapor in the winter arctic tropopause region is important because, after the tropical tropopause region, the winter arctic tropopause has the coldest temperatures in the tropospheric northern hemisphere. This suggests the potential for cloud formation that can remove water vapor from a part of the atmosphere where radiatively active gases (such as water) exert a disproportionate influence on the earth's radiation budget. Previous work by the same authors has shown that this cloud formation extends into the stratosphere, with 20% of the parcels having ozone values of 300-350 ppbv experiencing ice saturation in any given 10 day period period during the late winter. In fact, temperatures are cold enough that 5-10% of the parcels experience saturation even if the water content is below the prevailing stratospheric value of 5 ppmv. This work describes a case study of clouds observed by aircraft near the winter arctic tropopause during the SAGE Ozone Loss and Validation Experiment (SOLVE). This provided a unique opportunity to examine dehydration processes in this region since in situ water, tracer, cloud particle, and meteorological data were all available simultaneously. During this period, temperatures were cold enough at the tropopause to produce saturation mixing ratios of 3-4 ppmv. Thus, clouds were actually observed within the stratosphere. Back trajectories indicate that the air in these clouds came from lower latitudes and altitudes. The study describes the nature of the clouds, the history of the air, and the possible implications for the upper tropospheric water budget.

Pfister, Leonhard; Selkirk, Henry; Anderson, Bruce; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark; Hipskind, R. Stephen (Technical Monitor)

2002-01-01

163

Front Matter: Volume 8825  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8825, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Dhere, Neelkanth G.; Wohlgemuth, John H.; Lynn, Kevin W.

2013-09-01

164

Front Matter: Volume 8912  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8912 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

SPIE, Proceedings of

2013-08-01

165

Front Matter: Volume 8827  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8827, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Eich, Manfred; Nunzi, Jean-Michel; Jakubiak, Rachel

2013-09-01

166

Front Matter: Volume 8821  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8821, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Plesniak, Adam P.

2013-09-01

167

Front Matter: Volume 8905  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8905 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Amzajerdian, Farzin; Aksnes, Astrid; Chen, Weibiao; Gao, Chunqing; Zheng, Yongchao; Wang, Cheng

2013-09-01

168

Front Matter: Volume 8914  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8914 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

SPIE, Proceedings of

2013-08-01

169

Front Matter: Volume 8824  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8824, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Sulima, Oleg V.; Conibeer, Gavin

2013-09-01

170

Front Matter: Volume 8826  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8826, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Reutzel, Edward W.

2013-09-01

171

Front Matter: Volume 8904  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8904, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Tünnermann, Andreas; Liu, Zejin; Wang, Pu; Tang, Chun

2013-09-01

172

Front Matter: Volume 8823  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8823, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Eldada, Louay A.; Heben, Michael J.

2013-09-01

173

Radar Backscatter Across the Gulf Stream Sea Surface Temperature Front  

NASA Technical Reports Server (NTRS)

Ocean backscatter signatures were measured by the Jet Propulsion Laboratory airborne NUSCAT K(sub u)-band scatterometer across the Gulf Stream sea surface temperature front. The measurements were made during the Surface Wave Dynamics Experiment (SWADE) off the coast of Virginia and Maryland in the winter of 1991.

Nghiem, S. V.; Li, F. K.; Walsh, E. J.; Lou, S. H.

1998-01-01

174

Migration of Fennoscandian lesser white-fronted geese Anser erythropus mapped by satellite telemetry  

Microsoft Academic Search

Since staging and wintering sites of the globally threatened lesser white-fronted goose Anser erythropus are poorly known, satellite transmitters were used to map autumn and winter migration routes of four individuals. After having spent c. 2 weeks at a post-moulting staging place in Finnmark, north Norway, all individuals flew directly to the Kanin Peninsula, northwest Russia. Later, two of the

Svein-Håkon Lorentsen; Ingar Jostein Øien; Tomas Aarvak

1998-01-01

175

Winter Olympic Sports  

NSDL National Science Digital Library

Exploring Winter Olympic Sports Let's take a look at some of the different winter olympic sports Alpine Skiing Biathalon Bobsleigh Cross country Curling Figure Skating Freestyle skiing Ice Hockey Luge Nordic Combined Short track speed skating Skeleton Ski Jumping Snowboard Speed Skating ...

Keller, Mrs.

2010-01-23

176

Winter Math Activities  

NSDL National Science Digital Library

This webpage of winter math activities includes seasonal activities for patterns, graphing, symmetry, estimations, and glyphs. Other resources on this page include literature connections, links to more winter resources, and pictures of student work. Activities are centered on penguins, snowflakes, snowman, and gingerbread.

Kawas, Terry

2013-01-01

177

Winter Art Education Project  

ERIC Educational Resources Information Center

The purpose of this article is to describe how the Department of Art Education at the University of Lapland in Finland has developed winter art as a method of environmental and community-based art education. I will focus on the Snow Show Winter Art Education Project, a training project funded by the European Union and the State Provincial Office…

Jokela, Timo

2007-01-01

178

A late winter hydrographic section from Tasmania to Antarctica  

Microsoft Academic Search

A hydrographic section between Tasmania and Antarctica was occupied in late winter 1991 as part of the World Ocean Circulation Experiment (WOCE). The primary purpose of the WOCE repeat section SR3 is to measure the exchange between the Indian and Pacific Oceans south of Australia. This paper describes the fronts, water masses and transport observed on the first occupation of

Stephen R. Rintoul; John L. Bullister

1999-01-01

179

Influence of Winter Temperatures on the Yielding Ability of Highbush Blueberries (Vaccinium corymbosum L.) Cultivars in Belarus  

Microsoft Academic Search

Temperature conditions during the winter determine the cold injury suffered by the reproductive organs of the highbush blueberry and, thus, it's yielding ability. Alternation of thawing and freezing periods can reduce the winter hardiness of blueberries. When atmospheric temperatures are reduced gradually after winter thawing periods, blueberry plants are able to regain hardiness. The majority of blueberry cultivars possess ecological

Nikolai Pavlovski

2010-01-01

180

Early Childhood: The World in Winter.  

ERIC Educational Resources Information Center

Various winter activities and experiences for young children are suggested. These include a getting ready for winter walk in the fall, winter birds, winter clothing, traveling in winter, winter sky watch, and others. (JN)

McIntyre, Margaret, Ed.

1983-01-01

181

86. DETAIL VIEW OF FRONT WROUGHT IRON GRILL ON FRONT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

86. DETAIL VIEW OF FRONT WROUGHT IRON GRILL ON FRONT WINDOW, NORTHWEST FRONT, THE TACKLE BOX, LOOKING SOUTHEAST - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

182

Sources of frontogenesis in the Equatorial Atlantic Front  

NASA Astrophysics Data System (ADS)

The Equatorial Atlantic front is located along 1°N in the eastern equatorial Atlantic basin, at the northern boundary of the cold tongue. It separates the cold waters of the southern cold tongue from the warmest, tropical waters circulating in the Gulf of Guinea. This seasonal front appears every year from May to August, and is characterized by meridional SST gradients up to 2 to 3°C/20 km. It is thought to play an important role for the circulation in the marine atmospheric boundary layer and influence the coastal precipitation and the western African monsoon onset. In this presentation the processes at the origin of the equatorial front were investigated. For that, diagnosis of the frontogenesis forcings were applied on a realistic high-resolution simulation of the equatorial Atlantic in 2006. It is found that the turbulent forcing term associated with the mixed layer turbulent heat fluxes is frontolitic (meaning a destruction of the front). However, a splitting of the turbulent forcing into its low and high-frequency (wavy) components, indicates that the low-frequency forcing may initiate the equatorial front, a forcing that is finally amplified and fully maintained by dynamical effects. Finally, the dynamic forcing has a leading frontogenetic role (meaning a reinforcement of the front) and is fully driven by the meridional convergence between the Guinea Current and the South Equatorial Current.

Giordani, Hervé; Caniaux, Guy

2014-05-01

183

Negative Ion Density Fronts  

SciTech Connect

Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas.

Igor Kaganovich

2000-12-18

184

Impact of declining Arctic sea ice on winter snowfall  

PubMed Central

While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in midlatitudes and clearly different interannual variability than the classical Arctic oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.

Liu, Jiping; Curry, Judith A.; Wang, Huijun; Song, Mirong; Horton, Radley M.

2012-01-01

185

Relativistic Runaway Ionization Fronts  

NASA Astrophysics Data System (ADS)

We investigate the first example of self-consistent impact ionization fronts propagating at relativistic speeds and involving interacting, high-energy electrons. These fronts, which we name relativistic runaway ionization fronts, show remarkable features such as a bulk speed within less than one percent of the speed of light and the stochastic selection of high-energy electrons for further acceleration, which leads to a power-law distribution of particle energies. A simplified model explains this selection in terms of the overrun of Coulomb-scattered electrons. Appearing as the electromagnetic interaction between electrons saturates the exponential growth of a relativistic runaway electron avalanche, relativistic runaway ionization fronts may occur in conjunction with terrestrial gamma-ray flashes and thus explain recent observations of long, power-law tails in the terrestrial gamma-ray flash energy spectrum.

Luque, A.

2014-01-01

186

Front Matter: Volume 8910  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8910, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Zhang, Lifu; Yang, Jianfeng

2013-08-01

187

Front Matter: Volume 8908  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8908, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

SPIE, Proceedings of

2013-08-01

188

Front Matter: Volume 8808  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8808, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

SPIE, Proceedings of

2013-09-01

189

Front Matter: Volume 8911  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8911, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Gu, Min; Yuan, Xiaocong; Qiu, Min

2013-08-01

190

Front Matter: Volume 8809  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8809, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

SPIE, Proceedings of

2013-09-01

191

Front Matter: Volume 8609  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8609, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

2013-03-01

192

Front Matter: Volume 8909  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8909, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Rahm, Marco; Vodopyanov, Konstantin; Shi, Wei; Zhang, Cunlin

2013-08-01

193

Front Matter: Volume 8906  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume 8906, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

SPIE, Proceedings of

2013-08-01

194

Front Matter: Volume 6429  

NASA Astrophysics Data System (ADS)

This PDF file contains the front matter associated with SPIE Proceedings Volume XXXX, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

SPIE, Proceedings of

2007-03-01

195

Lakota Winter Counts  

NSDL National Science Digital Library

Different human societies across the millennia have sought to record their histories in a multitude of ways, and the Lakota people of the Northern Plains elected to record their experiences through what are known as winter counts. These winter counts are essentially histories or calendars in which events are recorded by pictures, with one picture for each year. These rather fascinating documents were used in conjunction with extensive oral histories, and as such, most of these events were widely known and recognized by a majority of the Lakota. This particular website from the National Anthropological Archives at the Smithsonian National Museum of Natural History allows visitors to view these winter counts, learn more about the Lakota, and view interviews with contemporary Lakota people about the winter counts. The site also contains an audio glossary and a number of helpful resources for educators.

196

In Depth Winter Weather  

NSDL National Science Digital Library

Winter Weather is an In-Depth Special Report form the National Center for Atmospheric Research. It contains articles, images, activities, video clips, and interactive graphs to inform learners about meteorology and weather in the colder seasons.

2012-01-01

197

Science of Winter  

NSDL National Science Digital Library

Is it true that no two snowflakes are alike? What happens to mosquitoes when the mercury drops? National Geographic Channel explores the planet's most extreme season. This engaging three-minute video discusses the astronomical basis for winter, and other seasons, based on the angle of incidence of the sun's rays relative to the Northern and Southern Hemispheres, as well as the components of intense winter storms.

198

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. What ...

Haight, Jennifer

2010-02-22

199

Warmest winter in history  

NSDL National Science Digital Library

For four days last week, the daily temperatures outside the Internet Scout Project office here in Wisconsin soared above 60 F (and on one day, above 75 F), and the lakes that surround Madison melted in one fell swoop, bringing winter to a lurching halt and restless thoughts of summer to the forefront. While such local temperature anomalies are not surprising (nor did other cities experience the same highs), in this case, they fit in with a global trend that continues to raise -- in some cases, anxious -- eyebrows. On Friday, the National Oceanic and Atmospheric Administration (NOAA) announced that this winter is the warmest on record. Surpassing recent warm winter records of 1997-1998, the winter of 1999-2000 has now clinched the somewhat dubious title of warmest winter in history. This news release comes on the coat tails of a January report from the National Academy of Sciences confirming what is already accepted among most scientists -- that global warming is real (see the January 14, 2000 Scout Report). For news and information on this warmest of winters, this week's In The News features seven sites, listed above.

Payne, Laura X.

200

Antifreeze Proteins in Winter Rye Leaves Form Oligomeric Complexes1  

PubMed Central

Antifreeze proteins (AFPs) similar to three pathogenesis-related proteins, a glucanase-like protein (GLP), a chitinase-like protein (CLP), and a thaumatin-like protein (TLP), accumulate during cold acclimation in winter rye (Secale cereale) leaves, where they are thought to modify the growth of intercellular ice during freezing. The objective of this study was to characterize the rye AFPs in their native forms, and our results show that these proteins form oligomeric complexes in vivo. Nine proteins were separated by native-polyacrylamide gel electrophoresis from apoplastic extracts of cold-acclimated winter rye leaves. Seven of these proteins exhibited multiple polypeptides when denatured and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After isolation of the individual proteins, six were shown by immunoblotting to contain various combinations of GLP, CLP, and TLP in addition to other unidentified proteins. Antisera produced against individual cold-induced winter rye GLP, CLP, and TLP all dramatically inhibited glucanase activity in apoplastic extracts from cold-acclimated winter rye leaves, and each antiserum precipitated all three proteins. These results indicate that each of the polypeptides may be exposed on the surface of the protein complexes. By forming oligomeric complexes, AFPs may form larger surfaces to interact with ice, or they may simply increase the mass of the protein bound to ice. In either case, the complexes of AFPs may inhibit ice growth and recrystallization more effectively than the individual polypeptides.

Yu, Xiao-Ming; Griffith, Marilyn

1999-01-01

201

Winter's Polar Vortex Ushers in Spring's 'Pollen Vortex'  

MedlinePLUS

... experts say that the long, cold winter kept trees dormant for longer than usual, which means tree pollen season will overlap with grass pollen and ... the Chicago area in February because that's when tree pollen usually starts. "It was impossible in February ...

202

Crow Deaths Caused by West Nile Virus during Winter  

PubMed Central

In New York, an epizootic of American crow (Corvus brachyrhynchos) deaths from West Nile virus (WNV) infection occurred during winter 2004–2005, a cold season when mosquitoes are not active. Detection of WNV in feces collected at the roost suggests lateral transmission through contact or fecal contamination.

Stone, Ward B.; Ebel, Gregory D.; Young, David S.; Galinski, David S.; Pensabene, Jason P.; Franke, Mary A.; Eidson, Millicent; Kramer, Laura D.

2007-01-01

203

Influence of a warm ocean current on regional climate in winter  

Microsoft Academic Search

In East Asia, the Siberian high pressure system expels a cold northerly monsoon, resulting in the lower atmosphere receiving plenty of moisture when it meets the ocean. From this, every winter a huge amount of snow is provided from cumulus clouds for the north and west side of the Japanese Islands. But we also find that the winter precipitation in

N. Hirose; K. Fukudome; K. Nishimura; M. Yamamoto

2010-01-01

204

Modifications of abscisic acid level in winter oilseed rape leaves during acclimation of plants to freezing temperatures  

Microsoft Academic Search

An almost twofold increase in abscisic acid (ABA) content was observed in the leaves of winter oilseed rape plants (Brassica napus L., var. oleifera L., cv. Jantar) grown in the cold (>0°C). This ABA increase took place during the first three days of cold treatment. After 6 days of plant growth in the cold, the level of ABA started to

Gabriela Smole?ska-Sym; Helena Gawro?ska; Alina Kacperska

1995-01-01

205

Characterizing the growth and cold hardiness of Zoysia spp  

Microsoft Academic Search

Zoysiagrass (Zoysia spp.) is a warm-season grass well-adapted to lawns and golf turfs that requires minimal inputs. Key barriers to widespread zoysiagrass use are slow establishment rate and poor cold hardiness. Therefore, my objective was to determine the physiological basis for differences in growth and cold hardiness of zoysiagrass. Field studies first quantified differences in establishment rate and winter injury

Aaron J Patton

2006-01-01

206

Role of mixed layer depth in surface frontogenesis: The Agulhas Return Current front  

NASA Astrophysics Data System (ADS)

interaction processes that modify the sea surface temperature (SST) front in the Agulhas Return Current region (between 40°E and 55°E) during austral summer and winter are examined using observational data and output from a high-resolution ocean general circulation model. While the air-sea heat flux frontal variations tend to relax the SST front, the frontolysis is amplified (damped) in summer (winter) when frontal variations in the mixed layer depth (MLD) are incorporated. The stronger (weaker) frontolysis associated with the MLD variations is due to the fact that the warming (cooling) by the surface heat flux is amplified south of the front where the MLD is shallower and is reduced north of the front where the MLD is deeper. This study is the first to show that the MLD variations play an important role in affecting the strength of the SST front.

Tozuka, Tomoki; Cronin, Meghan F.

2014-04-01

207

The Fabled Maine Winter  

NSDL National Science Digital Library

No study of Maine weather would be complete without analysis of the year of 1816 - the year with no summer in an area from western Pennsylvania and New York, up through Quebec and across to Maine and the Canadian maritimes. In this five-unit lesson, students will investigate the causes and effects of the Fabled Maine Winter by exploring a variety of data sources. They will locate, graph, and analyze meteorological and climatological data for Portland, Maine, for more recent years to try to find one that most closely resembles the fabled Maine winter of 1816.

208

Winter Storm (weather)  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. First think about these questions: 1. What is your favorite aspect of winter weather? 2. How does the weather effect your everyday life? Form groups of THREE. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper... 1. In general, when are winds formed? 2. When winds are blowing, how can you ...

Miller, Aubree

2009-09-28

209

When hot water freezes before cold  

Microsoft Academic Search

I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the

J. I. Katz

2006-01-01

210

The relationship between body mass and survival of wintering canvasbacks  

USGS Publications Warehouse

Mass and recapture histories of 6,000 Canvasbacks (Aythya valisineria ) banded in upper Chesapeake Bay were used to test two hypotheses: (1) early-winter body mass is associated with the probability of surviving the winter, and (2) early-winter body mass is associated with annual survival probability. Results for adult males, which provided the largest data sets, presented strong evidence that birds with high relative early-winter masses had both greater overwinter and annual survival probabilities. Results of overwinter analyses necessarily are qualified by the alternative explanation of mass-dependent emigration, i.e. the possibility that lighter birds move south in response to cold weather and leave only heavy birds for recapture. Such a phenomenon remains to be documented.

Haramis, G.M.; Nichols, J.D.; Pollock, K.H.; Hines, J.E.

1986-01-01

211

Project COLD.  

ERIC Educational Resources Information Center

Describes Project COLD (Climate, Ocean, Land, Discovery) a scientific study of the Polar Regions, a collection of 35 modules used within the framework of existing subjects: oceanography, biology, geology, meterology, geography, social science. Includes a partial list of topics and one activity (geodesic dome) from a module. (Author/SK)

Kazanjian, Wendy C.

1982-01-01

212

Nuclear Winter: The implications for civil defense  

SciTech Connect

''Nuclear Winter'' is the term given to hypothesized cooling in the northern hemisphere following a nuclear war due to injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the original paper in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. The widespread use of 3-dimensional global circulation models have resulted in reduced estimates of cooling; 15 to 25/sup 0/C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought are likely to be direct threats to human survival for populations with the wherewithal to survive normal January temperatures; The principal threat from nuclear winter is to food production, and could present problems to third parties without food reserves; and Loss of a crop year is neither a new nor unexpected threat from nuclear war to the US and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the US due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year. 6 refs.

Chester, C.V.; Perry, A.M.; Hobbs, B.F.

1987-01-01

213

Crack front waves  

NASA Astrophysics Data System (ADS)

We present simulations of 3 D dynamic fracture which suggest that a persistent elastic wave is generated in response to a localized perturbation of a propagating crack front, e.g., by a local heterogeneity of critical fracture energy. The wave propagates along the moving crack front and spreads, relative to its origin point on the fractured surface, at a speed slightly below the Rayleigh speed. The simulations were done using the spectral elastodynamic methodology of Geubelle and Rice (1995). They model failure by a displacement-weakening cohesive model, which corresponds in the singular crack limit to crack growth at a critical fracture energy. Confirmation that crack front waves with properties like in our simulation do exist has been provided by Ramanathan and Fisher (1997). Through a derivation based on the linearized perturbation analysis of dynamic singular tensile crack growth by Willis and Movchan (1995), those authors found by numerical evaluation that a transfer function thereby introduced has a simple pole at a certain {?}/{?} ratio, corresponding to a non-dispersive wave. Further, we show that as a consequence of these persistent waves, when a crack grows through a region of small random fluctuations in fracture energy, the variances of both the local propagation velocity and the deformed slope of the crack front increase, according to linearized perturbation theory, in direct proportion to distance of growth into the randomly heterogeneous region. That rate of disordering is more rapid than the growth of the variances with the logarithm of distance established by Perrin and Rice (1994) for a model elastodynamic fracture theory based on a scalar wave equation. That scalar case, which shows slowly decaying (as t - {1}/{2}) rather than persistent crack front waves, is analyzed here too.

Morrissey, John W.; Rice, James R.

1998-03-01

214

Titan's Emergence from Winter  

NASA Technical Reports Server (NTRS)

We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

2011-01-01

215

Winter Playscape Dreaming  

ERIC Educational Resources Information Center

Winter, like all seasons, adds a new sense of mystery and discovery to the world of young children. It is the time when they can study snowflakes, find icicles, or observe the birds that share their yards. This article presents ideas and suggestions on how to plan a playscape. A playscape is a man-made seasonal playground for young children. It…

Keeler, Rusty

2006-01-01

216

PLCO News, Winter 2001  

Cancer.gov

PLCO News, Winter 2001 Cancer Information Service If you have a question about cancer, call and speak with a trained specialist at NCI's Cancer Information Service (CIS). The CIS operates a nationwide toll-free telephone hotline Monday-Friday, 9:00 a.m.

217

PLCO News, Winter 2001  

Cancer.gov

PLCO News, Winter 2001 Trial Update Enrollment goal: 148,000 Total enrollment (as of November 30, 2000): 152,139 Men enrolled: 75,565 Women enrolled: 76,574 Number of people enrolled at age: 55-59 49,944 60-64 47,058

218

Winter 1988 Daedalus  

Microsoft Academic Search

The last issue of Daedalus, Journal of the American Academy of Arts and Sciences, Winter 1988, is devoted to artificial intelligence--Al, for short. It is always interesting to know what is the official position of the intellectual establishment on intellectual matters, especially where much grant allocation is concentrated.

Joseph Agassi

1988-01-01

219

The News. Winter 2007  

ERIC Educational Resources Information Center

This Winter 2007 quarterly newsletter from the Community College League of California includes: (1) Incumbents: Some Win, Some Lose in November Trustee Elections; (2) Voters Approve $2 Billion in Bonds; (3) Photos from the "Together We Can" conference; (4) Report, Media Criticize Transfer, Completion Rates and Colleges; (5) District Leader…

Giles, Ray, Ed.

2007-01-01

220

3. VIEW NORTH, SOUTHWEST FRONT, SOUTHEAST SIDE Front and side ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW NORTH, SOUTHWEST FRONT, SOUTHEAST SIDE Front and side elevation. Note gasoline sign post added. Flush store window not altered, 1900 clapboard siding and panelling remaining. - 510 Central Avenue (Commercial Building), Ridgely, Caroline County, MD

221

35. EAST FRONT OF POWERHOUSE AND CAR BARN: East front ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. EAST FRONT OF POWERHOUSE AND CAR BARN: East front of powerhouse and car barn. 'Annex' is right end of building. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

222

Hot, Cold, and Really Cold.  

ERIC Educational Resources Information Center

Describes a physics experiment investigating temperature prediction and the relationship between the physical properties of heat units, melting, dissolving, states of matter, and energy loss. Details the experimental setup, which requires hot and cold water, a thermometer, and ice. Notes that the experiment employs a deliberate counter-intuitive…

Leyden, Michael

1997-01-01

223

Taxonomy of Greater White-fronted Geese (Aves: Anatidae)  

USGS Publications Warehouse

Five subspecies of the Greater White-fronted Goose, Anser albifrons (Scopoli, 1769), have been named, all on the basis of wintering birds, and up to six subspecies have been recognized. There has been confusion over the application of some names, particularly in North America, because of lack of knowledge of the breeding ranges and type localities, and incorrect taxonomic decisions. There is one clinally varying subspecies in Eurasia, one that breeds in Greenland, and three in North America, one newly named herein.

Banks, Richard C.

2011-01-01

224

Are summit metabolism and thermogenic endurance correlated in winter-acclimatized passerine birds?  

PubMed

Small birds exhibiting marked winter improvement of cold tolerance also show elevated summit metabolic rates (maximum cold-induced metabolic rate) in winter relative to summer. However, relatively large increases in cold tolerance can occur with only minor increments of maximum cold-induced metabolic rate and geographic variation in cold tolerance is not always positively correlated with variation in maximum cold-induced metabolic rate. Thus, it is uncertain whether maximum cold-induced metabolic rate and cold tolerance are phenotypically correlated in small birds and no previous study has directly examined this relationship. I measured maximum cold-induced metabolic rate and cold tolerance (i.e., thermogenic endurance) over three winters in black-capped chickadees Poecile atricapillus, American tree sparrows Spizella arborea, and dark-eyed juncos Junco hyemalis. For raw thermogenic endurance data, residuals of maximum cold-induced metabolic rate and thermogenic endurance from mass regressions were significantly and positively correlated in juncos and tree sparrows, and their correlation approached significance for chickadees. Log10 transformation of thermogenic endurance and mass data gave similar results. These data provide the first direct evidence for a phenotypic correlation between maximum cold-induced metabolic rate and thermogenic endurance in small birds, although much of the variance in thermogenic endurance is explained by factors other than maximum cold-induced metabolic rate and the degree of correlation differs among species. Nevertheless, these data suggest that physiological adjustments producing elevated thermogenic endurance also produce elevated maximum cold-induced metabolic rate in small birds. PMID:11585259

Swanson, D L

2001-08-01

225

Coping with Cold Sores  

MedlinePLUS

... What's that? Adam wondered. What Is a Cold Sore? Cold sores are small blisters that is reddish ... always found inside the mouth.) What Causes Cold Sores? Cold sores are caused by a virus called ...

226

ARIEL front end  

NASA Astrophysics Data System (ADS)

The ARIEL project at TRIUMF will greatly expand the variety and availability of radioactive ion beams (RIBs) (Laxdal, Nucl Inst Methods Phys Res B 204:400-409, 2003). The ARIEL front end connects the two ARIEL target stations to the existing ISAC facility to expand delivery to two and eventually three simultaneous RIB beams with up to two simultaneous accelerated beams (Laxdal et al. 2008). The low-energy beam transport lines and mass separators are designed for maximum flexibility to allow a variety of operational modes in order to optimize the radioactive ion beam delivery. A new accelerator path is conceived for high mass delivery from an EBIS charge state breeder. The front-end design utilizes the experience gained in 15 years of ISAC beam delivery.

Marchetto, M.; Baartman, R. A.; Laxdal, R. E.

2014-01-01

227

Farmers’ Market Expands to Offer Products in Winter | Poster  

Cancer.gov

The 2013 National Cancer Institute (NCI) at Frederick Farmers’ Market regular season may have closed, but that doesn’t mean customers who want fresh produce, handmade crafts, and other homemade goodies from local vendors are out of luck. Winter Markets, which began Jan. 7, will be held every other Tuesday, from 11 a.m. to 1 p.m., in front of Building 549 or in the Café Room, depending on the weather.

228

Radiative thermal conduction fronts  

NASA Astrophysics Data System (ADS)

The discovery of the O VI interstellar absorption lines in our Galaxy by the Copernicus observatory was a turning point in our understanding of the Interstellar Medium (ISM). It implied the presence of widespread hot (approx. 10 to the 6th power K) gas in disk galaxies. The detection of highly ionized species in quasi-stellar objects' absorption spectra may be the first indirect observation of this hot phase in external disk galaxies. Previous efforts to understand extensive O VI absorption line data from our Galaxy were not very successful in locating the regions where this absorption originates. The location at interfaces between evaporating ISM clouds and hot gas was favored, but recent studies of steady-state conduction fronts in spherical clouds by Ballet, Arnaud, and Rothenflug (1986) and Bohringer and Hartquist (1987) rejected evaporative fronts as the absorption sites. Researchers report here on time-dependent nonequilibrium calculations of planar conductive fronts whose properties match well with observations, and suggest reasons for the difference between the researchers' results and the above. They included magnetic fields in additional models, not reported here, and the conclusions are not affected by their presence.

Borkowski, Kazimierz J.; Balbus, Steven A.; Fristrom, Carl C.

1990-07-01

229

Radiative thermal conduction fronts  

NASA Technical Reports Server (NTRS)

The discovery of the O VI interstellar absorption lines in our Galaxy by the Copernicus observatory was a turning point in our understanding of the Interstellar Medium (ISM). It implied the presence of widespread hot (approx. 10 to the 6th power K) gas in disk galaxies. The detection of highly ionized species in quasi-stellar objects' absorption spectra may be the first indirect observation of this hot phase in external disk galaxies. Previous efforts to understand extensive O VI absorption line data from our Galaxy were not very successful in locating the regions where this absorption originates. The location at interfaces between evaporating ISM clouds and hot gas was favored, but recent studies of steady-state conduction fronts in spherical clouds by Ballet, Arnaud, and Rothenflug (1986) and Bohringer and Hartquist (1987) rejected evaporative fronts as the absorption sites. Researchers report here on time-dependent nonequilibrium calculations of planar conductive fronts whose properties match well with observations, and suggest reasons for the difference between the researchers' results and the above. They included magnetic fields in additional models, not reported here, and the conclusions are not affected by their presence.

Borkowski, Kazimierz J.; Balbus, Steven A.; Fristrom, Carl C.

1990-01-01

230

Lightning Protection against Winter Lightning  

Microsoft Academic Search

Winter lightning, which occurs along the Sea of Japan coast, often damages transmission lines and distribution lines with the conventional lightning protection. These lines in mountainous areas suffer extensive damage from winter lightning. It is very important to investigate the features of lightning outages in detail to improve the lightning protection measures against winter lightning, therefore observations of lightning strokes

Hitoshi Sugimoto

2007-01-01

231

Lyot Crater in Winter  

NASA Technical Reports Server (NTRS)

19 January 2004 This somewhat oblique Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red wide angle view of Lyot Crater and the mesas of the Deuteronilus Mensae was acquired in January 2004 on the day after the Mars Exploration Rover, Spirit, landed in Gusev Crater on the other side of the planet. It is winter in the northern hemisphere of Mars, and winter for Lyot Crater means clouds. The brighter features in the atmosphere above the surface in this image are clouds. Lyot Crater is about 236 km (147 mi.) in diameter. The center of this image is near 48.5oN, 331.0oW, and is illuminated from the lower left.

2004-01-01

232

Winter cardiovascular diseases phenomenon.  

PubMed

THIS PAPER REVIEW SEASONAL PATTERNS ACROSS TWELVE CARDIOVASCULAR DISEASES: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. PMID:23724401

Fares, Auda

2013-04-01

233

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? What is a better indicator of moisture in the air? 4. What happens when there is low ...

Xuan

2010-02-22

234

winter storm applicator  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. What causes the wind to blow. 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Jones, Cory

2009-09-28

235

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Barbieri, Mikel

2012-02-13

236

Winter weather activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather Maker Simulator Use the weather simulation above to answer the following questions in complete sentences on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there is high ...

Frankovic, Whitney

2009-09-28

237

Winter Storm Warning  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

2009-09-28

238

Al's Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Al

2010-02-22

239

Storm Winter Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

KateOlsen58

2009-09-28

240

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Butcher, Kirsten

2008-09-26

241

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Ferraratechclassroom

2012-02-06

242

Staying Warm Winter Experiments  

NSDL National Science Digital Library

These experiments use simple materials to prove that a lot of one's body heat escapes from one's head and that wearing a hat stops some of this heat loss. In addition, students consider how sitting directly on cold ground will cause one to lose heat faster than sitting on insulating material.

243

Changes in carbohydrates, ABA and bark proteins during seasonal cold acclimation and deacclimation in Hydrangea species differing in cold hardiness.  

PubMed

Cold injury is frequently seen in the commercially important shrub Hydrangea macrophylla but not in Hydrangea paniculata. Cold acclimation and deacclimation and associated physiological adaptations were investigated from late September 2006 to early May 2007 in stems of field-grown H. macrophylla ssp. macrophylla (Thunb.) Ser. cv. Blaumeise and H. paniculata Sieb. cv. Kyushu. Acclimation and deacclimation appeared approximately synchronized in the two species, but they differed significantly in levels of mid-winter cold hardiness, rates of acclimation and deacclimation and physiological traits conferring tolerance to freezing conditions. Accumulation patterns of sucrose and raffinose in stems paralleled fluctuations in cold hardiness in both species, but H. macrophylla additionally accumulated glucose and fructose during winter, indicating species-specific differences in carbohydrate metabolism. Protein profiles differed between H. macrophylla and H. paniculata, but distinct seasonal patterns associated with winter acclimation were observed in both species. In H. paniculata concurrent increases in xylem sap abscisic acid (ABA) concentrations ([ABA](xylem)) and freezing tolerance suggests an involvement of ABA in cold acclimation. In contrast, ABA from the root system was seemingly not involved in cold acclimation in H. macrophylla, suggesting that species-specific differences in cold hardiness may be related to differences in [ABA](xylem). In both species a significant increase in stem freezing tolerance appeared long after growth ceased, suggesting that cold acclimation is more regulated by temperature than by photoperiod. PMID:18636985

Pagter, Majken; Jensen, Christian R; Petersen, Karen K; Liu, Fulai; Arora, Rajeev

2008-11-01

244

Hierarchical wave-front sensing.  

PubMed

We present a new wave-front sensing technique for adaptive optics based on use of several wave-front sensors dedicated to the sensing of a different range of spatial frequencies. We call it a hierarchical wave-front sensor. We present the concept of a hierarchical wave-front sensor and apply it to the Shack-Hartmann sensor. We show the gain that is expected with two Shack-Hartmann sensors. We obtain a gain that increases with the size of the largest sensor, and we detail the application of hierarchical wave-front sensing to extreme adaptive optics and extremely large telescopes. PMID:15678767

Le Roux, Brice; Coyne, Julien; Ragazzoni, Roberto

2005-01-10

245

Nonclassical Cold-Frontal Structure Caused by Dry Subcloud Air in Northern Utah during the Intermountain Precipitation Experiment (IPEX)  

Microsoft Academic Search

The purpose of the Intermountain Precipitation Experiment (IPEX) is to improve understanding of precipitating systems in the Intermountain West. Instrumentation deployed during the field phase of IPEX sampled a strong cold front and associated convection that moved through northern Utah on 14-15 February 2000. The surface cold front was characterized by a sharp temperature drop (88C in 8 min), strong

David M. Schultz; Robert J. Trapp

2003-01-01

246

Simple front tracking  

SciTech Connect

A new and simplified front tracking algorithm has been developed as an aspect of the extension of this algorithm to three dimensions. Here the authors emphasize two main results: (1) a simplified description of the microtopology of the interface, based on interface crossings with cell block edges, and (2) an improved algorithm for the interaction of a tracked contact discontinuity with an untracked shock wave. For the latter question, they focus on the post interaction jump at the contact, which is a purely 1D issue. Comparisons to other methods, including the level set method, are included.

Glimm, J.; Grove, J.W.; Li, X.; Zhao, N.

1999-04-01

247

Common cold  

PubMed Central

Introduction Each year, children suffer up to 5 colds and adults have 2-3 infections, leading to time off school or work, and considerable discomfort. Most symptoms resolve within a week, but coughs often persist for longer. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for common cold? We searched: Medline, Embase, The Cochrane Library and other important databases up to May 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 19 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: analgesics or anti-inflammatory drugs, antibiotics, antihistamines, decongestants (norephedrine, oxymetazoline, or pseudoephedrine), decongestants plus antihistamine, echinacea, steam inhalation, vitamin C, and zinc (intranasal gel or lozenges).

2008-01-01

248

Common cold  

PubMed Central

Introduction Each year, children suffer up to 5 colds and adults have two to three infections, leading to time off school or work, and considerable discomfort. Most symptoms resolve within 1 week, but coughs often persist for longer. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for common cold? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 21 systematic reviews and RCTs that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: analgesics or anti-inflammatory drugs, antibiotics, antihistamines, decongestants for short-term and for long-term relief, decongestants plus antihistamines, echinacea, steam inhalation, vitamin C, and zinc (intranasal gel or lozenges).

2011-01-01

249

Affections of SSTa in North Atlantic and Arctic Ocean on cold air activity over the east China marginal seas  

NASA Astrophysics Data System (ADS)

Using monthly mean sea surface temperature anomaly (SSTa) in the Northern Atlantic and Arctic from 1951-2004,the reanalysis data of sea surface pressure, air temperature and geopotential height at 500 hPa, SVD analysis were done to study the relations among the SSTa's and the cold air activity over the east China marginal seas. It is found that?in boreal winter, cold air activity over the east China marginal seas can be predicted by the SSTa in the Northern Atlantic and Arctic by the Autumn?the positive SSTa in northern Atlantic and negative SSTa in regions south of Iceland and Greenland during September, October and November, can resulted to the pressure increasing over the east China marginal seas; lower sea surface temperature in the east sea of Novaya Zemlya, and higher SST in the east sea of Novaya Zemlya, northwest of Barents Sea together with lower SST in southeast of the Barents Sea during September, October and November coincides with higher sea level pressure of China east coast. The mechanism in these affections is that positive SSTa in the Northern Atlantic can make the development of bridge at the 500hPa; higher SST in north Atlantic coincides with the development of high-altitude ridge, and then the ridge extends to the north, coincides with higher Geopotential height over the area between Novaya Zemlya and Urals. The Negative vorticity advection in front of the ridge leads cold air to key areas, then affects China east coast area, and then forms surface cold anticyclone, and vice versa. Key words?Northern Atlantic; sea regions around Novaya Zemlya?SST anomaly? SVD analysis?east China marginal seas?cold air activity

Sun, Jilin; Shi, Xiaomeng; Jiao, Yan; Ye, Xinxin

2010-05-01

250

Winter Frost and Fog  

NASA Technical Reports Server (NTRS)

This somewhat oblique blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 174 km (108 mi) diameter crater, Terby, and its vicinity in December 2004. Located north of Hellas, this region can be covered with seasonal frost and ground-hugging fog, even in the afternoon, despite being north of 30oS. The subtle, wavy pattern is a manifestation of fog.

Location near: 28oS, 286oW Illumination from: upper left Season: Southern Winter

2005-01-01

251

Winter Hypertension: Potential mechanisms  

PubMed Central

Hypertension exhibits a winter peak and summer trough in countries both north and south of the equator. A variety of explanations have been proposed to account for the seasonal nature of hypertension. It is likely that this reflects seasonal variations in risk factors. Seasonal variations have been demonstrated in a number of risk factors may play essential roles for seasonality of hypertension such as noradrenalin, catecholamine and vasopressin, vitamin D, and serum cholesterol. However, a number of studies have also suggested a direct effect of environmental temperature and physical activity on blood pressure. This paper was design to review the available evidence on seasonal variations in hypertension and possible explanations for them.

Fares, Auda

2013-01-01

252

Chaffinch and Winter Wren  

NSDL National Science Digital Library

Every morning when he walks the dog, retired professor of natural history Peter Slater can identify as many as thirty birds by their song alone. On a walk in a Scottish town with Ari Daniel Shapiro, Slater explains what two common songsters, the chaffinch and winter wren, are singing about, and how even city dwellers can learn to âbird by earâ in their own neighborhoods, with rewarding results. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

2009-01-01

253

Big6 Winter Production  

NSDL National Science Digital Library

Goals: a. Students will be able to identify the four seasons. b. Students will be able to identify three animals (bear, goose, moose) and know their lifestyle patterns in congruence with the four seasons, especially Winter months. c. Students will develop an understanding of their environment. 2nd Grade Standard III: Students will develop an understanding of their environment Objective 2: Observe and describe weather Goal C: Describe how weather affects people and weather Lesson Objectives: a. Identify the seasons and represent each with pictures and songs. b. Observe and describe typical weather for each of ...

Cook, Mrs.

2010-11-05

254

winter storm activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. It provides an interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Prested, Miss

2010-05-26

255

Characterization of multiple cold induced genes from Ammopiptanthus mongolicus and functional analyses of gene AmEBP1  

Microsoft Academic Search

In comparison to herbaceous plants, studies of cold responsive genes and cold signaling in woody perennials are limited. Since\\u000a most woody plants have evolved freezing tolerance (FT) in winter, together with similar lignified structures and winter adaptive\\u000a mechanisms, it is more likely to find cold resistant genes in woody plants growing in temperate and arctic regions. In this\\u000a study, Ammopiptanthus

Pengxiu Cao; Jian Song; Chunjiang Zhou; Manli Weng; Jing Liu; Fuxin Wang; Feng Zhao; Dianqi Feng; Bin Wang

2009-01-01

256

Sensitivity of winter chill models for fruit and nut trees to climatic changes expected in California's Central Valley  

Microsoft Academic Search

Many fruit and nut crops require cold temperatures in winter to break dormancy. Quantifying this chilling requirement and selecting appropriate cultivars for the climate of a growing region is crucial for successful cultivation of such crops. Several models exist to quantify winter chill, and each growing region uses a model that has been shown to perform well under local climatic

Eike Luedeling; Minghua Zhang; Volker Luedeling; Evan H. Girvetz

2009-01-01

257

From the front  

SciTech Connect

The causes of recent dynamic thinning of Greenland's outlet glaciers have been debated. Realistic simulations suggest that changes at the marine fronts of these glaciers are to blame, implying that dynamic thinning will cease once the glaciers retreat to higher ground. For the last decade, many outlet glaciers in Greenland that terminate in the ocean have accelerated, thinned, and retreated. To explain these dynamic changes, two hypotheses have been discussed. Atmospheric warming has increased surface melting and may also have increased the amount of meltwater reaching the glacier bed, increasing lubrication at the base and hence the rate of glacier sliding. Alternatively, a change in the delicate balance of forces where the glacier fronts meet the ocean could trigger the changes. Faezeh Nick and colleagues5 present ice-sheet modeling experiments that mimic the observations on Helheim glacier, East Greenland, and suggest that the dynamic behaviour of outlet glaciers follows from perturbations at their marine fronts. Greenland's ice sheet loses mass partly through surface melting and partly through fast flowing outlet glaciers that connect the vast plateau of inland ice with the ocean. Earlier ice sheet models have failed to reproduce the dynamic variability exhibited by ice sheets over time. It has therefore not been possible to distinguish with confidence between basal lubrication from surface meltwater and changes at the glaciers' marine fronts as causes for the observed changes on Greenland's outlet glaciers. But this distinction bears directly on future sea-level rise, the raison d'etre of much of modern-day glaciology: If the recent dynamic mass loss Greenland's outlet glaciers is linked to changing atmospheric temperatures, it may continue for as long as temperatures continue to increase. On the other hand, if the source of the dynamic mass loss is a perturbation at the ice-ocean boundary, these glaciers will lose contact with that perturbation after a finite amount of thinning and retreat. Therefore, the first hypothesis implies continued retreat of outlet glaciers into the foreseeable future, while the second does not -- provided the bedrock topography prohibits a connection between the retreating glacier and the ocean. Nick and coauthors test the physical mechanisms implied in each hypotbesis in an innovative ice-flow model, and use that model to try to match a time series of observations from Helheim glacier, one of Greenland's three largest outlet glaciers. Along with many observations, the simulations strongly support the contention that the recent retreat of Greenland's outlet glaciers is the result of changes at their marine fronts.Further, the simulations confirm the earlier hypotheses that bedrock topography largely controlled Helheim glacier's rapid acceleration and retreat in 2004 and 2005, and its deceleration and stabilization in 2006. Finally, the current work implies that if requirements of observational data (high-resolution bed topography) and computational resources (fine computational grid resolution) can be met, improved predictive capability for ice-sheet models is attainable. With respect to the concerns raised by the IPCC, this study signals progress.

Price, Stephen [Los Alamos National Laboratory

2009-01-01

258

Spirit's Winter Work Site  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Annotated Version

This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. Spirit was parked on a slope tilted 11 degrees to the north to maximize sunlight during the southern winter season. 'Tyrone' is an area where the rover's wheels disturbed light-toned soils. Remote sensing and in-situ analyses found the light-toned soil at Tyrone to be sulfate rich and hydrated. The original picture is catalogued as PSP_001513_1655_red and was taken on Sept. 29, 2006.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

2006-01-01

259

Occurrence of winter air temperature extremes in Central Spitsbergen  

NASA Astrophysics Data System (ADS)

The occurrence of daily air temperature extremes in winter in Central Spitsbergen in the period 1975-2008 was analysed. The mean winter temperature was found to be increasing by approximately 1.65°C per decade. Negative extremes were becoming less frequent, decreasing at a rate of approximately 5 days per decade, whereas the frequency of positive extremes showed a small (2 days per decade) but insignificant positive trend. Furthermore, circulation patterns responsible for positive and negative temperature extremes were analysed. Composite maps of the sea level pressure (SLP) and 500-hPa geopotential heights (z500 hPa) means and anomalies were constructed for the days with positive and negative extremes. Circulation patterns causing extremely warm winter days are characterised by a cyclonic centre or a low pressure trough over the Fram Strait. Cyclones located west of Spitsbergen with a warm sector over the archipelago bring warm air masses from the southern quadrant. On extremely cold days, the cyclone centres are usually located over the Barents Sea. This SLP pattern implies airflow from the north and northeast that brings cold Arctic air to the North Atlantic. Another factor in the occurrence of the temperature extremes in Central Spitsbergen is the sea-ice cover. Negative temperature extremes usually occur together with a high concentration of sea ice, particularly in the middle and end of winter.

Bednorz, Ewa

2011-12-01

260

AMBIPOLAR DIFFUSION-MEDIATED THERMAL FRONTS IN THE NEUTRAL INTERSTELLAR MEDIUM  

SciTech Connect

In a thermally bistable medium, cold, dense gas is separated from warm, rarefied gas by thin phase transition layers, or fronts, in which heating, radiative cooling, thermal conduction, and convection of material are balanced. We calculate the steady-state structure of such fronts in the presence of magnetic fields, including the processes of ion-neutral drift and ion-neutral frictional heating. We find that ambipolar diffusion efficiently transports the magnetic field across the fronts, leading to a flat magnetic field strength profile. The thermal profiles of such fronts are not significantly different from those of unmagnetized fronts. The near uniformity of the magnetic field strength across a front is consistent with the flat field strength-gas density relation that is observed in diffuse interstellar gas.

Stone, Jennifer M.; Zweibel, Ellen G. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States)

2010-11-20

261

The Physics Front  

NSDL National Science Digital Library

Richard Feynman was one of the great communicators and scholars within the field of physics, and his very accessible lectures remain the stuff of legend today. While Professor Feynman is no longer with us, physics teachers can avail themselves of the very nice resources offered at The Physics Front. Created by the American Association of Physics Teachers and the National Science Foundation, the site contains lesson plans, activities, labs, and other pedagogical tools for physics teachers. The site also is notable for its âÂÂFirst Time Physics Teachersâ section which contains a bit of information about the nature of teaching physics and how these resources might be best used in the classroom. The âÂÂActivitiesâ area of the site is a real treat, as educators can find activities by subject, which include optics, energy, momentum, and wave energy.

262

Recent trends in winter temperature extremes in eastern China and their relationship with the Arctic Oscillation and ENSO  

NASA Astrophysics Data System (ADS)

Interannual variations in the number of winter extreme warm and cold days over eastern China (EC) and their relationship with the Arctic Oscillation (AO) and El Niño-Southern Oscillation (ENSO) were investigated using an updated temperature dataset comprising 542 Chinese stations during the period 1961-2011. Results showed that the number of winter extreme warm (cold) days across EC experienced a significant increase (decrease) around the mid-1980s, which could be attributed to interdecadal variation of the East Asian Winter Monsoon (EAWM). Probability distribution functions (PDFs) of winter temperature extremes in different phases of the AO and ENSO were estimated based on Generalized Extreme Value Distribution theory. Correlation analysis and the PDF technique consistently demonstrated that interannual variation of winter extreme cold days in the northern part of EC (NEC) is closely linked to the AO, while it is most strongly related to the ENSO in the southern part (SEC). However, the number of winter extreme warm days across EC has little correlation with both AO and ENSO. Furthermore, results indicated that, whether before or after the mid-1980s shift, a significant connection existed between winter extreme cold days in NEC and the AO. However, a significant connection between winter extreme cold days in SEC and the ENSO was only found after the mid-1980s shift. These results highlight the different roles of the AO and ENSO in influencing winter temperature extremes in different parts of EC and in different periods, thus providing important clues for improving short-term climate prediction for winter temperature extremes.

Chen, Shangfeng; Chen, Wen; Wei, Ke

2013-11-01

263

Winter Clouds Over Mie  

NASA Technical Reports Server (NTRS)

12 March 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red wide angle image shows late winter clouds over the 104 km (65 mi) diameter crater, Mie. Cellular clouds occur in the lower martian atmosphere, surrounding Mie Crater. Their cloudtops are at an altitude that is below the crater rim. Higher than the crater rim occurs a series of lee wave clouds, indicating air circulation moving from west/northwest (left) toward the east/southeast (right). Mie Crater is located in Utopia Planitia, not too far from the Viking 2 landing site, near 48.5 N, 220.4 W. Sunlight illuminates this January 2004 scene from the lower left.

2004-01-01

264

Spirit Scans Winter Haven  

NASA Technical Reports Server (NTRS)

At least three different kinds of rocks await scientific analysis at the place where NASA's Mars Exploration Rover Spirit will likely spend several months of Martian winter. They are visible in this picture, which the panoramic camera on Spirit acquired during the rover's 809th sol, or Martian day, of exploring Mars (April 12, 2006). Paper-thin layers of light-toned, jagged-edged rocks protrude horizontally from beneath small sand drifts; a light gray rock with smooth, rounded edges sits atop the sand drifts; and several dark gray to black, angular rocks with vesicles (small holes) typical of hardened lava lie scattered across the sand.

This view is an approximately true-color rendering that combines images taken through the panoramic camera's 753-nanometer, 535-nanometer, and 432-nanometer filters.

2006-01-01

265

Winter fuels report  

SciTech Connect

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and state and local governments on the following topics: distillate fuel oil net production, imports and stocks for all PADD's and product supplied on a US level; propane net product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition and underground storage for the United States and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil for those states participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the United States and selected cities; and US total heating degree-days by city. 27 figs, 12 tabs.

Not Available

1990-11-29

266

Cold confusion  

SciTech Connect

On March 23 two chemists, Martin Fleischmann and Stanley Pons startled the world with a press conference at the University of Utah where they announced that they had achieved nuclear fusion at room temperatures. As evidence they cited the production of ''excess'' amounts of heat in an electrochemical apparatus and observation of neutron production. While the production of heat in a chemical apparatus is not in itself unusual the observation of neutrons is certainly extraordinary. As it turned out, though, careful measurements of the neutron production in electrochemical apparatus similar to that used by Fleischmann and Pons carried out at dozens of other laboratories has shown that the neutron production fails by many orders of magnitude to support the assertion by Fleischmann and Pons that their discovery represents a new and cheap source of fusion power. In particular, independent measurements of the neutron production rate suggest that the actual rate of fusion energy production probably does not exceed 1 trillionth of a watt. This paper discusses the feasibility that cold fusion is actually being achieved. 7 refs.

Chapline, G.

1989-07-01

267

Spring Staging Areas of the Greenland White-fronted Goose (Anser albifrons flavirostris) in West Greenland  

Microsoft Academic Search

The Greenland white-fronted goose (Anser albifrons flavirostris) migrates about 3000 km from wintering grounds in Ireland and Britain to breeding grounds in West Greenland (64? - 72?N). The migration route includes long flights over the ocean and over the Greenland ice cap. To obtain optimal reproduction output, it is important for the geese to build up their condition at specific

CHRISTIAN M. GLAHDER

1999-01-01

268

EFFECTS OF CLIMATE CHANGE ON VEGETATION AND ECOSYSTEM SERVICES IN THE COLORADO FRONT RANGE  

EPA Science Inventory

If climate change leads to an extended growing season and somewhat wetter winters in the Front Range of Colorado, then a new time period of resource availability will be created. Non-native vegetation whose native lands possessed climates similar to the ?new conditions? may be...

269

Surface properties of ocean fronts  

NASA Technical Reports Server (NTRS)

Background information on oceanic fronts is presented and the results of several models which were developed to study the dynamics of oceanic fronts and their effects on various surface properties are described. The details of the four numerical models used in these studies are given in separate appendices which contain all of the physical equations, program documentation and running instructions for the models.

Wolff, P. M.; Hubert, W. E.

1976-01-01

270

Identifying Lagrangian fronts with favourable fishery conditions  

NASA Astrophysics Data System (ADS)

Lagrangian fronts (LFs) in the ocean are defined as boundaries between surface waters with strongly different Lagrangian properties. They can be accurately detected in a given velocity field by computing synoptic maps for displacements of synthetic tracers and other Lagrangian indicators. We use Pacific saury catch and location data for a number of commercial fishery seasons in the region of the northwest Pacific with one of the richest fishery in the world. It is shown statistically that the saury fishing grounds with maximal catches are not randomly distributed over the region but located mainly along the sharp LFs where productive cold waters of the Oyashio Current, warmer waters of the southern branch of the Soya Current, and waters of warm-core Kuroshio rings converge. Computation of those fronts in altimetric geostrophic velocity fields both in the years with the First and Second Oyashio Intrusions shows that in spite of different oceanographic conditions LF locations may serve as good indicators of potential fishing grounds. Possible biophysical reasons for saury aggregation near sharp LFs are discussed. We propose a mechanism for effective export of nutrient rich waters based on stretching of material lines in the vicinity of hyperbolic objects in the ocean. The developed method, based on identifying LFs in any velocity fields, is quite general and may be applied to find potential fishing grounds for the other pelagic fish.

Prants, S. V.; Budyansky, M. V.; Uleysky, M. Yu.

2014-08-01

271

Cold-Weather Sports  

MedlinePLUS

Ahh, winter! Shorter days. Frigid temperatures. Foul weather. What better time to be outdoors? Winter sports can help you burn calories, increase your cardiovascular fitness, and strengthen muscles. Activities that are ...

272

Mesoscale numerical simulations of heavy nocturnal rainbands associated with coastal fronts in the Mediterranean Basin  

NASA Astrophysics Data System (ADS)

Three offshore rainbands associated with nocturnal coastal fronts formed near the Israeli coastline, the Gulf of Genoa and on the northeastern coast of the Iberian Peninsula, are simulated using version 3.3 of the WRF-ARW mesoscale model in order to study the dynamics of the atmosphere in each case. The simulations show coastal fronts producing relatively high (in comparison with some other similar rainbands) 1 and 10 h accumulated precipitations that formed in the Mediterranean Basin. According to these simulations, the coastal fronts that formed near the Israeli coastline and over the Gulf of Genoa are quasi-stationary, while the one that formed on the northeastern coast of the Iberian Peninsula moves away from the coast. For the three events, we evaluate and intercompare some parameters related to convective triggering, deceleration induced by the cold pool in the upstream flow, and the blockage that the cold coastal front offers to the warmer maritime air mass.

Mazon, J.; Pino, D.

2014-05-01

273

The Anomalous Winter of 1783-1784: Was the Laki Eruption or an Analog of the 2009-2010 Winter to Blame?  

NASA Technical Reports Server (NTRS)

The multi ]stage eruption of the Icelandic volcano Laki beginning in June, 1783 is speculated to have caused unusual dry fog and heat in western Europe and cold in North America during the 1783 summer, and record cold and snow the subsequent winter across the circum-North Atlantic. Despite the many indisputable impacts of the Laki eruption, however, its effect on climate, particularly during the 1783.1784 winter, may be the most poorly constrained. Here we test an alternative explanation for the unusual conditions during this time: that they were caused primarily by a combined negative phase of the North Atlantic Oscillation (NAO) and an El Nino ]Southern Oscillation (ENSO) warm event. A similar combination of NAO ]ENSO phases was identified as the cause of record cold and snowy conditions during the 2009.2010 winter in Europe and eastern North America. 600-year tree-ring reconstructions of NAO and ENSO indices reveal values in the 1783.1784 winter second only to their combined severity in 2009.2010. Data sources and model simulations support our hypothesis that a combined, negative NAO ]ENSO warm phase was the dominant cause of the anomalous winter of 1783.1784, and that these events likely resulted from natural variability unconnected to Laki.

D'Arrigo, Rosanne; Seager, Richard; Smerdon, Jason E.; LeGrande, Allegra N.; Cook, Edward R.

2011-01-01

274

Fatality Assessment and Control Evaluation (FACE) Report for Michigan: Farmer Died When Front End Loader Bucket Struck Propane Tank Hidden by Snow, FACE-11-MI-006.  

National Technical Information Service (NTIS)

In the winter of 2011, a male farmer in his 50s died when the bucket of the front-end loader he was using to clear snow from a driveway struck a 500-gallon propane cylinder, causing a fireball which engulfed the front end loader. Approximately six to eigh...

2012-01-01

275

Recent research advances in cold-formed steel structures  

Microsoft Academic Search

Recent developments in the practical utilisation of cold-formed sections in building construction have taken place on three related fronts. There have been significant developments in the technology which result in more complex shapes with a higher yield stress so that cold-formed sections represent a particularly high-tech form of constructional steelwork. Developments in technology would be of little consequence unless there

J. M Davies

2000-01-01

276

Glycogen, not dehydration or lipids, limits winter survival of side-blotched lizards (Uta stansburiana).  

PubMed

Climate change is causing winters to become milder (less cold and shorter). Recent studies of overwintering ectotherms have suggested that warmer winters increase metabolism and decrease winter survival and subsequent fecundity. Energetic constraints (insufficient energy stores) have been hypothesized as the cause of winter mortality but have not been tested explicitly. Thus, alternative sources of mortality, such as winter dehydration, cannot be ruled out. By employing an experimental design that compared the energetics and water content of lizards that died naturally during laboratory winter with those that survived up to the same point but were then sacrificed, we attempt to distinguish among multiple possible causes of mortality. We test the hypothesis that mortality is caused by insufficient energy stores in the liver, abdominal fat bodies, tail or carcass or through excessive water loss. We found that lizards that died naturally had marginally greater mass loss, lower water content, and less liver glycogen remaining than living animals sampled at the same time. Periodically moistening air during winter reduced water loss, but this did not affect survival, calling into question dehydration as a cause of death. Rather, our results implicate energy limitations in the form of liver glycogen, but not lipids, as the primary cause of mortality in overwintering lizards. When viewed through a lens of changing climates, our results suggest that if milder winters increase the metabolic rate of overwintering ectotherms, individuals may experience greater energetic demands. Increased energy use during winter may subsequently limit individual survival and possibly even impact population persistence. PMID:22875774

Zani, Peter A; Irwin, Jason T; Rollyson, Mary E; Counihan, Jessica L; Healas, Sara D; Lloyd, Emily K; Kojanis, Lee C; Fried, Bernard; Sherma, Joseph

2012-09-01

277

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives  

NASA Astrophysics Data System (ADS)

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified ? T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive ? T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2013-02-01

278

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives.  

PubMed

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified ? T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive ? T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality. PMID:23423627

Grüebler, Martin U; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2014-07-01

279

Record-breaking Ozone Loss during Arctic Winter 2010/2011: Comparison with Arctic Winter 1996/1997  

NASA Astrophysics Data System (ADS)

Polar processing and chemical ozone loss is analysed during the Arctic winter/spring 2010/2011. The analyses with temperatures and potential vorticity (PV) data show a prolonged vortex from early December through mid-April. The PV maps illustrate strong vortex persistence in the lower stratosphere between 450 and 675 K, showing similar evolution with time. The minimum temperatures extracted from ECMWF data at 40-90°N show values below 195 K for a record period of first week of December through second week of April, indicating the longest period of colder temperatures for 17 years. At 10 hPa, there was a warming of about 10 K at 60°N and 40 K at 90°N around mid-January. The heat flux also showed high values in line with the increase in temperatures, of about 425 m K/s at 60°N at the same pressure level. However, the westerlies were strong (e.g. 35-45 m/s at 60°N) enough to keep the vortex intact until mid-April. Because of the cold temperatures in late winter and early spring, large areas of Polar Stratospheric Clouds (PSC) were found in the 400-600 K isentropic level range. Though the maximum values of PSCs area are smaller compared to other cold winters such as 2005, the extended period of presence of PSCs during this winter was exceptional, especially in late February-mid-March, in agreement with the cold temperatures during the period. Ozone loss analyses with high resolution Mimosa-Chim chemical transport model simulations show that the loss started by early January, and was about 0.5 ppmv in late January. The loss progressed slowly to 1 ppmv by the end of February, and then intensified by early March. The ozone depletion estimated by the passive method finds a maximum value of about 2-2.3 ppmv by the end of March-early April in the 450-550K range inside the vortex, which coincides with the areas of PSCs and high chlorine activation. This is the largest loss ever estimated with this model for any Arctic winter. It is consistent with the unprecedented chlorine activation that occurred in the winter, as the modeled ClO values show about 1.7 ppbv in early January and about 1 ppbv in March at 450-550K. This is longest period of chlorine activation noted among the Arctic winters. The ozone partial column loss reaches about 115-150 DU in the range 350 - 550 K. These model results for ozone, ozone loss and ClO are in good agreement with those found from Aura Microwave Limb Sounder observations. Since the winter 1996/1997 was also very cold in March - April, a comparison between both winters 2011 and 1997 will be presented, based on temperature, PV, Heat flux data and ozone loss estimations. Similarities and differences in the polar processing and ozone loss during both winters will be discussed using various measurements and model simulations. Copyright 2011. All rights reserved.

Godin Beekmann, S.; Kuttipurath, J.; Lefèvre, F.; Santee, M. L.; Froidevaux, L.

2011-12-01

280

Development of a model system to identify differences in spring and winter oat.  

PubMed

Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding. PMID:22253782

Chawade, Aakash; Lindén, Pernilla; Bräutigam, Marcus; Jonsson, Rickard; Jonsson, Anders; Moritz, Thomas; Olsson, Olof

2012-01-01

281

Decadal anomalies of winter precipitation over southern China in association with El Niño and La Niña  

NASA Astrophysics Data System (ADS)

Using multiple datasets, this paper analyzes the characteristics of winter precipitation over southern China and its association with warm and cold phases of El Niño-Southern Oscillation during 1948-2011. The study proves that El Niño is an important external forcing factor resulting in above-normal winter precipitation in southern China. The study also reveals that the impact of La Niña on the winter precipitation in southern China has a decadal variability. During the winter of La Niña before 1980, the East Asian winter monsoon is stronger than normal with a deeper trough over East Asia, and the western Pacific subtropical high weakens with its high ridge retreating more eastward. Therefore, anomalous northerly winds dominate over southern China, leading to a cold and dry winter. During La Niña winter after 1980, however, the East Asian trough is weaker than normal, unfavorable for the southward invasion of the winter monsoon. The India-Burma trough is intensified, and the anomalous low-level cyclone excited by La Niña is located to the west of the Philippines. Therefore, anomalous easterly winds prevail over southern China, which increases moisture flux from the tropical oceans to southern China. Meanwhile, La Niña after 1980 may lead to an enhanced and more northward subtropical westerly jet over East Asia in winter. Since southern China is rightly located on the right side of the jet entrance region, anomalous ascending motion dominates there through the secondary vertical circulation, favoring more winter precipitation in southern China. Therefore, a cold and wet winter, sometimes with snowy and icy weathers, would occur in southern China during La Niña winter after 1980. Further analyses indicate that the change in the spatial distribution of sea surface temperature anomaly during the La Niña mature phase, as well as the decadal variation of the Northern Hemisphere atmospheric circulation, would be the important reasons for the decadal variability of the La Niña impact on the atmospheric circulation in East Asia and winter precipitation over southern China after 1980.

Yuan, Yuan; Li, Chongyin; Yang, Song

2014-02-01

282

Cold Signaling and Cold Response in Plants  

PubMed Central

Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but non-freezing temperatures. This phenomenon is called cold acclimation. During cold acclimation, plants develop several mechanisms to minimize potential damages caused by low temperature. Cold response is highly complex process that involves an array of physiological and biochemical modifications. Furthermore, alterations of the expression patterns of many genes, proteins and metabolites in response to cold stress have been reported. Recent studies demonstrate that post-transcriptional and post-translational regulations play a role in the regulation of cold signaling. In this review article, recent advances in cold stress signaling and tolerance are highlighted.

Miura, Kenji; Furumoto, Tsuyoshi

2013-01-01

283

Close the Door--You're Letting the Cold In!  

NSDL National Science Digital Library

Actually no, you aren't letting the cold in when you leave the door open in winter. That's a common misconception that will be gently put to rest in this chapter. There will, however, be a discussion of the tranfer of energy that makes things hotter and colder.

Robertson, William C.

2002-01-01

284

COLD TEMPERATURE MOTOR VEHICLE EMISSIONS TESTING IN ALASKA  

EPA Science Inventory

A motor vehicle emissions testing study was conducted in Anchorage and Fairbanks during the winter of 1998-99 to collect actual measurements of initial idle emission rates. The study was performed for a sample of 111 automobiles and light-duty trucks under cold wintertime ambient...

285

Winter performance of an urban stormwater pond in southern Sweden  

NASA Astrophysics Data System (ADS)

Evidence from cold regions in North America has shown that the performance of stormwater ponds differs between winter and summer. The pond hydraulics change seasonally, and winters have lowered removal efficiency due to a combination of an ice cover, cold water and de-icing salts. This study examines the function of the Bäckaslov stormwater pond under the more mild conditions of southern Sweden, where there are several snow and melt cycles per year.Event sampling in the summer of 1997 showed good removal efficiencies for nutrients, total suspended solids (TSS) and a selection of metals (Cd, Cu, Pb, Zn), but winter grab-tests taken in 1995-96 and 1997-98 suggest that the pond acts as a pollutant source under cold conditions. To better assess winter and spring pond performance, water at the inflow and outflow was sampled from January to April 2003. The low intensity of runoff delivery and slow inflow velocities meant that time- rather than flow-weighted sampling was used. Five consecutive events were sampled and analysed for TSS, chloride and the metals As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. YSI probes were in place at both the inlet (pH, temperature) and outlet (pH, temperature, conductivity, dissolved oxygen) to determine the timing of pollution flows. In addition, profiles of the same quality indicators allowed snapshots of pond processes.De-icing salt has a major effect on pond hydraulics. Strong stratification occurred after each snowmelt-generated flow event and up to 80% of chloride could be retained by the pond. However, continuous conductivity measurements show that chloride is flushed between events. Ice changes retention times and causes oxygen depletion, but bed scour was not observed. Pond performance decreased during the winter and spring, albeit not as badly as the grab tests suggest. A seasonal comparison of the removal efficiencies showed that removal of Cd (75%) and Cu (49%) was about the same for summer and winter-spring, but removal of Pb, Zn and TSS dropped from 79%, 81% and 80% to 42%, 48% and 49% respectively. The removal efficiencies for the other metals sampled in 2003 were: As, 50%; Cr, 39%; Hg, 56%; Ni, 41%.

Semadeni-Davies, Annette

2006-01-01

286

Management of Wintering Bald Eagles.  

National Technical Information Service (NTIS)

Past declines in bald eagle numbers have accentuated the need for intensive species managment. Habitat requirements for nesting eagles have been determined, and some northern forests are presently managed for bald eagles. On the winter range, habitat encr...

K. Steenhof

1978-01-01

287

[Winter sports and shoulder arthroplasty].  

PubMed

Nowadays, a general negative evaluation of sportive activity regarding different kinds of sport following arthroplasty is at present no more scientifically supported. However, at present no valid guidelines regarding sportive activity of patients after implantation of shoulder joint arthroplasty exist. The question regarding the ability of performing winter sports activities of patients treated with shoulder joint endoprothesis has not been answered so far. Therefore the aim of the presented work was to identify winter sports-specific risks for patients treated with shoulder joint endoprothesis as well as to critically discuss the actual literature in refer to winter sport activities. Criteria for the education of patients with shoulder joint endoprothesis as well as consultation regarding winter sport activities will be provided for the orthopaedic surgeon. PMID:18814057

Kirchhoff, C; Imhoff, A B; Hinterwimmer, S

2008-09-01

288

Learners in Action, Winter 2005  

ERIC Educational Resources Information Center

This Winter 2005 issue of "Learners in Action" contains the following: (1) Proud Dad Turns Family Life Around (Nick Prince); (2) Learners Make a Great Impression at Conference; (3) The Story behind the Story; and (4) Learner Resources.

Movement for Canadian Literacy, 2005

2005-01-01

289

Survival in the Winter Storm.  

National Technical Information Service (NTIS)

Deals with the dangers inherent in winter weather. Gives advice to the average citizen on how to prepare for severe weather conditions, explains the meaning of specific forecasts, and pints up the necessity for emergency planning by local governments.

1994-01-01

290

The Challenge of Winter Backpacking.  

ERIC Educational Resources Information Center

Tips and techniques for safe and enjoyable winter backpacking are offered. Topics covered include cross county skis, snowshoes, clothing, footwear, shelter, sleeping bags, food, hypothermia prevention, as well as general rules and requirements. (CO)

Cavanaugh, Michael; Mapes, Alan

1981-01-01

291

Summer Hot Snaps and Winter Conditions: Modelling White Syndrome Outbreaks on Great Barrier Reef Corals  

PubMed Central

Coral reefs are under increasing pressure in a changing climate, one such threat being more frequent and destructive outbreaks of coral diseases. Thermal stress from rising temperatures has been implicated as a causal factor in disease outbreaks observed on the Great Barrier Reef, Australia, and elsewhere in the world. Here, we examine seasonal effects of satellite-derived temperature on the abundance of coral diseases known as white syndromes on the Great Barrier Reef, considering both warm stress during summer and deviations from mean temperatures during the preceding winter. We found a high correlation (r2?=?0.953) between summer warm thermal anomalies (Hot Snap) and disease abundance during outbreak events. Inclusion of thermal conditions during the preceding winter revealed that a significant reduction in disease outbreaks occurred following especially cold winters (Cold Snap), potentially related to a reduction in pathogen loading. Furthermore, mild winters (i.e., neither excessively cool nor warm) frequently preceded disease outbreaks. In contrast, disease outbreaks did not typically occur following warm winters, potentially because of increased disease resistance of the coral host. Understanding the balance between the effects of warm and cold winters on disease outbreak will be important in a warming climate. Combining the influence of winter and summer thermal effects resulted in an algorithm that yields both a Seasonal Outlook of disease risk at the conclusion of winter and near real-time monitoring of Outbreak Risk during summer. This satellite-derived system can provide coral reef managers with an assessment of risk three-to-six months in advance of the summer season that can then be refined using near-real-time summer observations. This system can enhance the capacity of managers to prepare for and respond to possible disease outbreaks and focus research efforts to increase understanding of environmental impacts on coral disease in this era of rapidly changing climate.

Heron, Scott F.; Willis, Bette L.; Skirving, William J.; Eakin, C. Mark; Page, Cathie A.; Miller, Ian R.

2010-01-01

292

Summer hot snaps and winter conditions: modelling white syndrome outbreaks on Great Barrier Reef corals.  

PubMed

Coral reefs are under increasing pressure in a changing climate, one such threat being more frequent and destructive outbreaks of coral diseases. Thermal stress from rising temperatures has been implicated as a causal factor in disease outbreaks observed on the Great Barrier Reef, Australia, and elsewhere in the world. Here, we examine seasonal effects of satellite-derived temperature on the abundance of coral diseases known as white syndromes on the Great Barrier Reef, considering both warm stress during summer and deviations from mean temperatures during the preceding winter. We found a high correlation (r(2) = 0.953) between summer warm thermal anomalies (Hot Snap) and disease abundance during outbreak events. Inclusion of thermal conditions during the preceding winter revealed that a significant reduction in disease outbreaks occurred following especially cold winters (Cold Snap), potentially related to a reduction in pathogen loading. Furthermore, mild winters (i.e., neither excessively cool nor warm) frequently preceded disease outbreaks. In contrast, disease outbreaks did not typically occur following warm winters, potentially because of increased disease resistance of the coral host. Understanding the balance between the effects of warm and cold winters on disease outbreak will be important in a warming climate. Combining the influence of winter and summer thermal effects resulted in an algorithm that yields both a Seasonal Outlook of disease risk at the conclusion of winter and near real-time monitoring of Outbreak Risk during summer. This satellite-derived system can provide coral reef managers with an assessment of risk three-to-six months in advance of the summer season that can then be refined using near-real-time summer observations. This system can enhance the capacity of managers to prepare for and respond to possible disease outbreaks and focus research efforts to increase understanding of environmental impacts on coral disease in this era of rapidly changing climate. PMID:20808912

Heron, Scott F; Willis, Bette L; Skirving, William J; Eakin, C Mark; Page, Cathie A; Miller, Ian R

2010-01-01

293

Changes in hematological profiles during winter field operations  

SciTech Connect

The authors have previously shown that there are changes in hematological profiles during experimental cold acclimation. They now report on hematological changes in 9 military volunteers during a 12 week winter field operation and show results similar to those observed during experimental cold acclimation. Blood was collected before and after completion of winter field operations and analyzed in a paired fashion. Hematocrit (HCT) and erythrocyte counts (RBC) were decreased; mean corpuscular hemoglobin concentration (MCHC) and plasma volume (PV), which was calculated from hemoglobin (Hb) concentration and HCT, were increased. In addition, the reticulocyte count was increased from 1.37 {plus minus} 0.10% to 2.62 {plus minus} 0.24% after completion of field operations. There was a statistically significant inverse correlation between HCT and reticulocyte count, indicating the need for an enhanced rate of red cell production. Hemoglobin concentration, leukocyte count, and mean corpuscular volume were unchanged. The RBC population, to remain at steady state during periods of chronic cold exposure, shows alterations in the number of circulating cells, Hb concentration per cell and possibly cell turnover.

Lopez, A.; Reed, L.; D'Alesandro, M. (Naval Medical Research Inst., Bethesda, MD (United States))

1991-03-11

294

A NEW MODEL TO ESTIMATE DAILY ENERGY EXPENDITURE FOR WINTERING WATERFOWL  

EPA Science Inventory

Activity budgets of wintering waterfowl have been widely used to assess habitat quality. However, when factors such as prey abundance or protection from exposure to cold or wind determine quality, measures of daily energy expenditure (DEE) may be more appropriate for this purpos...

295

Comparative analysis of the vernal and wintry thermally-induced structural front in the Baltic Sea on base of field data  

NASA Astrophysics Data System (ADS)

This study is a continuation of thermally-induced structural front investigation (a direct analogue of the lacustrine thermal bar - front, associated with the temperature of maximum density, Tmd = 3.98°C for the fresh waters) in the Baltic Sea during spring and winter periods. The manifestation and specific features of the vernal structural front after winters of varying severity were examined (Demchenko et al., 2011). The Baltic Sea exhibits 2 layers of salinity stratification, consisting of an upper freshened layer (down to a depth of 70 m in the Baltic proper) that is almost homogeneous in terms of salinity, and a more salty deep layer below the permanent pycno(halo) cline. The spring thermal front travels only to the upper layer, with the halocline playing the role of a 'liquid bottom'. The speed of structural front propagation is derived from an interplay of 3 physically different factors: (1) south-north variations in incoming solar radiation, (2) bottom and pycnocline topography, and (3) significant variation of the Tmd-value due to large horizontal salinity differences (increasing in a northerly direction). In the present study a comparative analysis of thermal structure in presence of the Tmd during spring and winter periods was performed. The following field data were analyzed (1) Subsurface temperature, salinity and chlorophyll-a along the sections Travemüende - Gdynia - Helsinki and Travemüende - Helsinki performed by Finnish Environment Institute for the spring 2010 and winter 2010-2011. (2) Subsurface temperature and salinity, measuring every hour during spring period 2010 and winter period 2010-2011 in the MARNET stations (Arkona basin, Darss Sill, courtesy of the BSH, www.bsh.de). It was concluded, that after severe winter 2010/2011 the vernal structural front, associated with the Tmd, has the same features as after severe winter 2002/2003. Thermal structural front is formed in winter as well; its specific features were revealed. The thermal front, developing near the gentle slopes, is much shaper in comparison with the front in the open Baltic. The two-phase propagation of the thermal front was observed; the speed of the Tmd was estimated for both seasons: vernal thermal front moves faster. The work is supported by grant of RFBR # 10-05-00472a, 11-05-90743_mob_st.

Demchenko, N.

2012-04-01

296

Seasonal variations in the responses of glycolytic intermediates of human erythrocytes to acute cold exposure  

NASA Astrophysics Data System (ADS)

Seven male students were studied to observe the effects of acute cold exposure (at 10°C for 60 min) on erythrocyte concentrations of glycolytic intermediates in summer and in winter. The subjects shivered slightly but frankly in both experiments. Significant decreases were observed in the concentrations of pyruvate and lactate during body cooling in summer, but not in winter. The lactate concentration remained significantly reduced 15 min after cold exposure. After 60 min of cold exposure in summer, a negative crossover point appeared to exist between phosphoenolpyruvate and pyruvate and erythrocyte pyruvate kinase activity showed a significant decrease. No seasonal difference was observed in the initial control values of the intermediates measured. From these results and the fact that glucose, pyruvate and lactate are evenly distributed between erythrocytes and plasma, it is likely that erythrocytes and skeletal muscles need less fuel substrate, glucose during cold exposure in winter than in summer, suggesting that an increased economy of energy for homeostasis is achieved.

Ohno, H.; Yahata, T.; Yamashita, K.; Kuroshima, A.

1988-03-01

297

Identifying the Western Pacific Salinity Front Using Aquarius Measurement  

NASA Astrophysics Data System (ADS)

Aquarius satellite mission is designed to measure high-resolution sea surface salinity both spatially and temporally. In this study, we smoothed the Aquarius salinity data on a 1/3*1/3 degree weekly gridded map over the western Pacific warm pool region. A sharp northeast-southwest oriented salinity front is seen in detail, but is not observed in the 1*1 degree monthly Argo map due to the low resolution. The salinity front (defined by the largest salinity gradient) is located close to 34.6 PSU isohaline (criteria generally used to define the location of salinity front), but is better defined with physical meanings. During the first four months of Aquarius measurement from Sep/2011-Dec/2011, the salinity front has penetrated much farther west than usual, associated with the westward shift of eastern edge of warm pool. Also, from the surface currents calculated from Ocean Surface Current Analyses - Real time (OSCAR), we notice that the strong westward currents enhance the zonal advection of sea surface temperature/salinity and bring the cold/salty water from central to western Pacific. This is related to the evolution of the central Pacific type of La Nina (i.e. cooling event centered in the central Pacific) in the end of 2011. The results also show that the salinity front shows up at the boundary between the south equatorial currents and north equatorial counter currents, suggesting the strong relationship between the formation of salinity front and the movement of salty and fresh water. Although further calibration/validation work is still ongoing, the preliminary results give us the confidence that the Aquarius measurement is going to help us better understand the fresh water flux and zonal advections in the western Pacific warm pool.

Kao, H.; Lagerloef, G.

2012-04-01

298

Heading for Next Winter Haven  

NASA Technical Reports Server (NTRS)

Approaching its 47th month of a Mars surface mission originally planned to last three months, NASA's Spirit rover was also approaching the northern edge of a low plateau called 'Home Plate.' The rover's operators selected an area with north-facing slope there as a destination where Spirit would have its best chance of surviving low-solar-energy conditions of oncoming Martian winter.

The yellow line on this map of the Home Plate area indicates Spirit's route from early February 2006, entering the mapped area from the north (top), to late November 2007, on the western edge of the bright-toned Home Plate plateau. The map covers an area about 160 meters (525 feet) across from west to east. Labels indicate the area intended for Spirit to spend many months spanning the rover's third Martian winter, the site where it spent about seven months (April to November 2006) spanning its second winter, and the site where it lost use of the drive motor for one of its six wheels.

A north-facing slope helps Spirit maximizes electric output from its solar panels during winter months because Spirit is in the southern hemisphere of Mars, so the sun appears only in the northern sky during winter. For the third winter, which will reach its minimum solar-energy days in early June 2008, Spirit faces the challenge of having more dust on its solar panels than it had during its second winter.

The base image for this map is a portion of a color image taken on Jan. 9, 2007, by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter.

2007-01-01

299

Fossils tell of mild winters in an ancient hothouse  

SciTech Connect

Fossil evidence from the Eocene points to a warmer winter climate in the continental interior (e.g. North Dakota) than that predicted by computer models. Paleobotanists have been able to quantify approximate winter mean temperatures by using leaf characteristics. As one example, leaves from colder climates have toothed edges. Leaf structure was correlated with modern climate regimes, and these relations were then applied to Eocene fossils. They found cold-month mean temperatures of 1-8[degrees]C in Wyoming and Montana, well above model predictions. Climate models can be manipulated to reproduce these temperatures, but not without overheating the entire globe. The problem could be that the Eocene atmospheric circulation was different from today, something not accounted for well by climate models.

Kerr, R.A.

1993-08-06

300

[A winter seasonal biotope of Culex pipiens autogenicus].  

PubMed

The authors describe an epigeal winter seasonal biotope of "culex pipiens autogenicus. The biotope consists of the irrigation system of the large Bervedere park of Tunis city. During the cold and rainy season the irrigation system is abandoned. Many water pools are formed in it in which C. pipiens and Culiseta longiareolata multiply. In summer the operation of the irrigation system brings about the disparition of the nests of larvae. Breeding performed from larvae collected in nature pointed out the autogenous and stenogam characters. Morphologically the specimens correspond to autogenous forms. The importance of the investigations is the evolution of the C. pipiens autogenic species in external nests of larvae during winter was pointed out. PMID:1243883

Dancesco, P; Chadli, A; Kchouk, M; Horak, M

1975-01-01

301

Review of 'cold fusion'.  

National Technical Information Service (NTIS)

This review describes the results from the following works: (1) to overview the chronological history of 'cold fusion' including the International Conferences on cold fusion (ICCF-3 and ICCF-4), (2) to overview the various theories which can explain the '...

1995-01-01

302

Exercising in Cold Weather  

MedlinePLUS

... to cold can cause health problems such as hypothermia, a dangerous drop in body temperature. If you ... hat, scarf, and gloves. Know the signs of hypothermia: l Watch for signs of hypothermia: cold feet ...

303

Impact of declining Arctic sea ice on northern hemisphere winter weather  

NASA Astrophysics Data System (ADS)

Judith Curry and Jiping Liu. An overview is provided of our recent paper that linked the decrease in autumn Arctic sea ice to changes in the winter Northern Hemispher atmospheric circulation that results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased regional heavy snowfalls. An analysis is provided of the last three winters. The need for a satellite-based assessment of cold-season open water surface sensible and latent heat fluxes is discussed.

Curry, J. A.; Liu, J.

2012-12-01

304

The Front-End System For MARE In Milano  

NASA Astrophysics Data System (ADS)

The first phase of MARE consists of 72 ?-bolometers composed each of a crystal of AgReO4 readout by Si thermistors. The spread in the thermistor characteristics and bolometer thermal coupling leads to different energy conversion gains and optimum operating points of the detectors. Detector biasing levels and voltage gains are completely remote-adjustable by the front end system developed, the subject of this paper, achieving the same signal range at the input of the DAQ system. The front end consists of a cold buffer stage, a second pseudo differential stage followed by a gain stage, an antialiasing filter, and a battery powered detector biasing set up. The DAQ system can be used to set all necessary parameters of the electronics remotely, by writing to a ?-controller located on each board. Fiber optics are used for the serial communication between the DAQ and the front end. To suppress interference noise during normal operation, the clocked devices of the front end are maintained in sleep-mode, except during the set-up phase of the experiment. An automatic DC detector characterization procedure is used to establish the optimum operating point of every detector of the array. A very low noise level has been achieved: about 3nV/?Hz at 1 Hz and 1 nV/?Hz for the white component, high frequencies.

Arnaboldi, Claudio; Pessina, Gianluigi

2009-12-01

305

Satellite evidence of wintertime atmospheric boundary layer responses to multiple SST fronts in the Japan Sea  

Microsoft Academic Search

We present satellite evidence of wintertime atmospheric boundary layer responses to multiple sea surface temperature (SST) fronts in the Japan Sea under cold-air outbreak during 22-28 December 2005. It is found that the lower atmosphere adheres to the stepwise SST variations, focusing on a wind trajectory from the Eurasian continent to the northern Japan, which goes through the meandering Polar

Teruhisa Shimada; Hiroshi Kawamura

2008-01-01

306

Satellite evidence of wintertime atmospheric boundary layer responses to multiple SST fronts in the Japan Sea  

Microsoft Academic Search

We present satellite evidence of wintertime atmospheric boundary layer responses to multiple sea surface temperature (SST) fronts in the Japan Sea under cold-air outbreak during 22–28 December 2005. It is found that the lower atmosphere adheres to the stepwise SST variations, focusing on a wind trajectory from the Eurasian continent to the northern Japan, which goes through the meandering Polar

Teruhisa Shimada; Hiroshi Kawamura

2008-01-01

307

Deuterium content of snow as an index to winter climate in the Sierra Nevada area  

USGS Publications Warehouse

The winter of 1968-69 produced two to three times the amount of precipitation in the Sierra Nevada area, California and Nevada, as the winter of 1969-70. The deuterium content in snow cores collected at the end of each winter at the same sites, which represents the total snowfall of each interval, shows a depletion in 1968-69 of approximately 20 per mil. The higher snowfall in 1968-69 and the depletion of deuterium can be explained by an uncommonly strong westward flow of cold air over and down the western slopes of the Sierras, which interacted with an eastward flow of moist Pacific air that overrode and mixed with the cold air; this resulted in precipitation that occurred in greater than normal amounts and at a lower than normal temperature. Pluvial periods of the Pleistocene may have had the same shift in air-mass trajectory as the wet 1968-69 year. Snow cores collected in the normal 1970-71 winter have deuterium concentrations that resemble those of the normal 1969-70 winter. Small and nonsystematic differences in samples from these two normal winters are due to variations in climatic character as well as to factors inherent in the sampling sites.

Friedman, I.; Smith, G. I.

1972-01-01

308

Effects of photoperiodically induced reproductive diapause and cold hardening on the cold tolerance of Drosophila montana.  

PubMed

Coping with seasonal and daily variation in environmental conditions requires that organisms are able to adjust their reproduction and stress tolerance according to environmental conditions. Females of Drosophila montana populations have adapted to survive over the dark and cold winters at high latitudes and altitudes by spending this season in photoperiodically controlled reproductive diapause and reproducing only in spring/summer. The present study showed that flies of a northern population of this species are quite tolerant of low temperatures and show high seasonal and short-term plasticity in this trait. Culturing the flies in short day length (nearly all females in reproductive diapause), as well as allowing the flies to get cold hardened before the cold treatment, increased the cold tolerance of both sexes both in chill coma recovery time test and in mortality assay. Chill coma recovery time test performed for the females of two additional D. montana populations cultured in a day length where about half of the females enter diapause, also showed that diapause can increase female cold tolerance even without a change in day length. Direct linkage between diapause and cold tolerance was found in only two strains representing a high-altitude population of the species, but the phenomenon will certainly be worth of studying in northern and southern populations of the species with larger data sets. PMID:20932841

Vesala, Laura; Hoikkala, Anneli

2011-01-01

309

Episodic Dust Events along Utah's Wasatch Front  

NASA Astrophysics Data System (ADS)

Episodic dust events contribute to hazardous air quality along Utah's Wasatch Front urban corridor and, through deposition onto the snowpack of the adjacent Wasatch Mountains, regional hydroclimate change. This study creates a climatology of these episodic dust events using surface-weather observations, GOES visible satellite imagery, and the North American Regional Analysis. In hourly weather observations from the Salt Lake International Airport (KSLC), a dust storm, blowing dust, and/or dust in suspension (i.e., dust haze) with a visibility 10 km (6 mi) or less occurs an average of ~4 days per water year (Oct-Sep), with considerable interannual variability during the 1930-2010 period of record. The monthly frequency of days with at least one dust report is strongly bimodal with primary and secondary maxima in Apr and Sep, respectively. Dust reports exhibit a strong diurnal modulation and are most common in the late afternoon and evening. Most recent (2001-2010) events observed at KSLC are produced by intermountain cyclones and/or cold-frontal troughs (i.e., cyclone/frontal), followed by outflow from airmass/monsoon convection. In the case of the former, dust is most frequently observed right around the time of cold frontal passage. GOES satellite imagery and backtrajectories of events at KSLC and in the surrounding region indicate that the primary dust emission sources are clustered in the deserts and dry lake beds of southern Utah as well as the burn area of the 2007 Milford Flat Fire and the Carson Sink of Nevada.

Massey, J.; Steenburgh, W. J.; Painter, T. H.

2011-12-01

310

The History of Winter: teachers as scientists  

NASA Astrophysics Data System (ADS)

The History of Winter (HOW) is a NASA Goddard Space Flight Center-funded teacher enrichment program that was started by Dr. Peter Wasilewski (NASA), Dr. Robert Gabrys (NASA) and Dr. Tony Gow (Cold Regions Research and Engineering Laboratory, or CRREL) in 2001 and continues with support and involvement of scientists from both the NASA Cryospheric Sciences Laboratory and CREEL. The program brings educators mostly from middle and high schools but also from state parks, community colleges and other institutions from across the US to the Northwood School (a small, private boarding school) in Lake Placid, NY for one week to learn about several facets of winter, polar, and snow research, including the science and history of polar ice core research, lake ice formation and structure, snow pack science, winter ecology, and remote sensing including current and future NASA cryospheric missions. The program receives support from the Northwood School staff to facilitate the program. The goal of the program is to create 'teachers as scientists' which is achieved through several hands-on field experiences in which the teachers have the opportunity to work with polar researchers from NASA, CRREL and partner Universities to dig and sample snow pits, make ice thin sections from lake ice, make snow shelters, and observe under-ice lake ecology. The hands-on work allows the teachers to use the same tools and techniques used in polar research while simultaneously introducing science concepts and activities to support their classroom work. The ultimate goal of the program is to provide the classroom teachers with the opportunity to learn about current and timely cryospheric research as well as to engage in real fieldwork experiences. The enthusiasm generated during the week-long program is translated into classroom activities with guidance from scientists, teachers and educational professionals. The opportunity to engage with polar researchers, both young investigators and renowned veterans in the field, is a unique experience for many of the teachers. Here we present lessons learned throughout the lifetime of the program, including successes and improvements made, and present our vision for the future of HOW.

Koenig, L.; Courville, Z.; Wasilewski, P. J.; Gow, T.; Bender, K. J.

2013-12-01

311

Cough and Cold Medicine Abuse  

MedlinePLUS

... and Cold Medicine Abuse DrugFacts: Cough and Cold Medicine Abuse Email Facebook Twitter Revised May 2014 Some ... diverted for abuse. How Are Cough and Cold Medicines Abused? Cough and cold medicines are usually consumed ...

312

Hypothermia: A Cold Weather Hazard  

MedlinePLUS

... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ... cold it is where you are. Check the weather forecasts for windy and cold weather. Try to ...

313

Winter 2009-2010: A case study of an extreme Arctic Oscillation event  

NASA Astrophysics Data System (ADS)

Winter 2009-2010 made headlines for extreme cold and snow in most of the major population centers of the industrialized countries of the Northern Hemisphere (NH). The major teleconnection patterns of the Northern Hemisphere, El Niño/Southern Oscillation (ENSO) and the Arctic Oscillation (AO) were of moderate to strong amplitude, making both potentially key players during the winter of 2009-2010. The dominant NH winter circulation pattern can be shown to have originated with a two-way stratosphere-troposphere interaction forced by Eurasian land surface and lower tropospheric atmospheric conditions during autumn. This cycle occurred twice in relatively quick succession contributing to the record low values of the AO observed. Using a skillful winter temperature forecast, it is shown that the AO explained a greater variance of the observed temperature pattern across the extratropical landmasses of the NH than did ENSO.

Cohen, Judah; Foster, James; Barlow, Mathew; Saito, Kazuyuki; Jones, Justin

2010-09-01

314

Calcium addition at the Hubbard Brook Experimental Forest reduced winter injury to red spruce in a high-injury year  

Microsoft Academic Search

Laboratory experiments have verified that acid-deposition-induced calcium (Ca) leaching reduces the foliar cold tolerance of red spruce (Picea rubens Sarg.) current-year foliage, increasing the risk of winter injury and crown deterioration. However, to date no studies have shown that ambient losses in soil Ca have resulted in increased winter injury in the field. In 2003, a year of severe region-wide

Gary J. Hawley; Paul G. Schaberg; Christopher Eagar; Catherine H. Borer

2006-01-01

315

Hydrogenation of soybean oil with commercial copper-chromite and nickel catalysts: Winterization of low-linolenate oils  

Microsoft Academic Search

Soybean oil hydrogenated in the presence of copper-chromite catalysts to 3% linolenate and below requires winterization if\\u000a it is to pass the cold test. Yields of winterized oil from soybean oil hydrogenated to several linolenate levels were therefore\\u000a studied. Partially hydrogenated soybean oil was sampled and filtered at intervals during hydrogenation on a pilot plant scale\\u000a with a commercial copper-chromite

K. J. Moulton; R. E. Beal; E. L. Griffin

1971-01-01

316

Teaching the French Popular Front.  

ERIC Educational Resources Information Center

Examines the French Popular Front of 1936 as a vehicle to investigate the turbulent decade of the 1930s. Reviews current historiography and discusses various facets of Leon Blum's government, examining the interrelationship of major economic and political forces. Concludes that the French Left still faces Blum's dilemma of implementing socialism…

Wall, Irwin M.

1987-01-01

317

STRUCTURAL FRONT UNIT GLOBAL APPROACH  

Microsoft Academic Search

The structural design of current vehicle front units has to account for an increasing number of constraints: improvement of real world performance in safety for occupants and others road users, perform in the various ratings and meet future regulations. Therefore the structural car design is the result of a compromise between pedestrian protection, car to car compatibility and self- protection.

Pascal Delannoy; Alain Diboine

318

Multiple WH-Fronting Constructions.  

ERIC Educational Resources Information Center

The unique position of WH words in Slavic languages is discussed, with specific reference to Bulgarian and Serbo-Croatian. The multiple fronting characteristics of Bulgarian and Serbo-Croatian differ in terms of the following positions and behaviors: extraction from embedded questions; clitic placement and other indications of constituent status;…

Rudin, Catherine

319

Front growth and local mixing  

Microsoft Academic Search

The instability produced if a shock or suddent acceleration takes place is known as Richtmyer-Meshkov (RM) instability. Front advance and mixing is studied analyzing mixedness,[2] the third order structure functions, that indicate strong inverse cascades towards the large scales producing spectral variations[3]. The mixing processes are compared by mapping the different intermittency and the multifractal scaling in the spike and

M. A. Sanchez; G. Garzon; J. M. Redondo

2009-01-01

320

Align the Front End First.  

ERIC Educational Resources Information Center

Discussion of management styles and front-end analysis focuses on a review of Douglas McGregor's theories. Topics include Theories X, Y, and Z; leadership skills; motivational needs of employees; intrinsic and extrinsic rewards; and faulty implementation of instructional systems design processes. (LRW)

Perry, Jim

1995-01-01

321

ARMING THE REVOLUTIONARY UNITED FRONT  

Microsoft Academic Search

On 7 July 1999, the government of Sierra Leone and the Revolutionary United Front (RUF) signed the Lomé Peace Agreement to end the civil war. A central component of this agreement called for the RUF to disarm. A year later, the RUF leader, Foday Sankoh, was in custody and the future of the peace accord in grave doubt. Far from

ERIC G BERMAN

2001-01-01

322

The structure of mountain fronts  

NASA Astrophysics Data System (ADS)

Commonly the part of a mountain front which is visible at the surface consists of foreland-dipping thrust belt rocks elevated above their regional structural position and overlain more or less conformably by molasse. Several explanations for their geometry are possible. (1) Major detachments exist within or beneath the molasse resulting in transport of the foreland basin. Examples of this geometry come from the Swiss Molasse Plain, the Southern Pyrenees and the Mackenzie Mountains of Canada. (2) Displacement is lost on major backthrusts beneath the frontal monocline. Examples cited here are the Rockies of Alberta, the Sulaiman Ranges of Pakistan, the Mackenzies, and the Andes in Peru. (3) Thrust sheets travelled over an old land surface and syntectonic molasse contemporaneously offlaps the topographic high of the thrust front. This phenomenon occurs along the Alpine thrust front in Haute Provence. (4) The frontal fold represents deformation above a large-scale thrust tip. No unequivocal example of tip line strain at this scale has been recorded although this type of deformation may occur in the Brooks Range of Alaska. In many areas mountain fronts show a combination of these idealized geometries.

Vann, I. R.; Graham, R. H.; Hayward, A. B.

323

Advanced RF Front End Technology  

NASA Technical Reports Server (NTRS)

The ability to achieve low-mass low-cost micro/nanospacecraft for Deep Space exploration requires extensive miniaturization of all subsystems. The front end of the Telecommunication subsystem is an area in which major mass (factor of 10) and volume (factor of 100) reduction can be achieved via the development of new silicon based micromachined technology and devices. Major components that make up the front end include single-pole and double-throw switches, diplexer, and solid state power amplifier. JPL's Center For Space Microsystems - System On A Chip (SOAC) Program has addressed the challenges of front end miniaturization (switches and diplexers). Our objectives were to develop the main components that comprise a communication front end and enable integration in a single module that we refer to as a 'cube'. In this paper we will provide the latest status of our Microelectromechanical System (MEMS) switches and surface micromachined filter development. Based on the significant progress achieved we can begin to provide guidelines of the proper system insertion for these emerging technologies. Additional information is contained in the original extended abstract.

Herman, M. I.; Valas, S.; Katehi, L. P. B.

2001-01-01

324

Interdecadal change in North Korean winter mean rainfall  

NASA Astrophysics Data System (ADS)

In the present study, it was found that there was a significant climate regime shift in 1993 from average rainfall amounts in winter (December of a year and January and February of the next year) in North Korea over the last 30 years (1982-2011). This significant climate regime shift in 1993 also appeared in empirical orthogonal function analysis conducted using the winter mean rainfall amounts observed at 26 weather observation stations in North Korea. The reason why winter mean rainfall amounts in North Korea were smaller during the period of 1994-2011 than during the period of 1982-1994 was that anomalous anticyclone was reinforced in regions near Lake Baikal while anomalous cyclone was reinforced on the sea on the east of Japan so that the winter pressure system pattern (west high-east low pattern) appeared and thus anomalous cold and dry northerlies were reinforced in most East Asian regions including North Korea. To figure out the reason why anomalous anticyclone was reinforced further in the East Asian continent in winters during the period of 1994-2011, differences in water equivalent of accumulated snow depths between the two periods were analyzed. As a result, more snow was observed in most East Asian regions during the period of 1994-2011. Therefore, anomalous anticyclone could be further reinforced in the East Asian continent because surface air temperature dropped further due to snow-albedo effect. The surface air temperature cooling deepened further in the East Asian continent during the period of 1994-2011 due to snow-albedo effect was identified through differences in sensible heat net flux between the two periods.

Choi, Ki-Seon; Kang, Sung-Dae; Kim, Hae-Dong

2013-10-01

325

Nitrate sequestration by corticolous macrolichens during winter precipitation events.  

PubMed

Nitrogen is an essential nutrient in the biogeochemistry of forested ecosystems. The influence of canopy lichens on the winter biogeochemistry of nitrate in broadleaved deciduous forests is examined and it is hypothesized that nitrate sequestration will not differ between winter precipitation events. Rejection of this hypothesis would mean that meteorological conditions of winter precipitation events have a detectable influence on nitrate sequestration by canopy lichens and nitrate input to the forest floor. Canopy lichens of the genus Parmelia were found to influence winter nitrate stemflow inputs to forest soils differentially. Epiphytic lichens on an individual Carya glabra Mill. (pignut hickory) canopy tree, centrally located within the stand of an open deciduous forest, actively sequestered nitrate leached from the tree's woody frame, lowering aqueous stemflow inputs at the tree base. The quantities of nitrate sequestered by corticolous lichens during the 2 February 1999 mixed-precipitation event were significantly greater than those during all other precipitation events examined. Greater rates of nitrate uptake during the 2 February 1999 event may be attributed to (1) its intermediate rain intensity, which would have soaked the lichen thalli in a nutrient-rich bath, and (2) an air temperature range between -2 degrees C and 8 degrees C that would have increased viscosity and surface tension of stemflow drainage, thereby decreasing stemflow velocity and increasing the contact time of stemflow water on the lichen thalli. Other precipitation events were either too cold to promote metabolic activity by canopy lichens or too warm and intense for an optimal contact time of stemflow with lichen thalli, resulting in lower quantities of nitrate sequestered. Meteorological conditions of winter precipitation events have been documented to influence sequestration of nitrate by corticolous lichens and decrease aqueous stemflow inputs to the forest floor of broadleaved deciduous forests. PMID:12135200

Levia, Delphis F

2002-05-01

326

Haemonchus contortus microtubules are cold resistant.  

PubMed

Haemonchus contortus is an important nematode of livestock that is present in most parts of the world. The life cycle comprises free living stages (egg, L1, L2 and L3 larvae), and parasitic stages (L4, adult and egg) in a ruminant. Microtubules are filamentous structures which are made from polymerization of ?- and ?-tubulin. In vitro polymerization of ?- and ?-tubulin can be achieved by increasing the temperature to 37°C under certain conditions. As part of its normal functioning, in mammals, the microtubules can be depolymerized when the temperature is reduced to 0°C. However, interestingly the microtubules of H. contortus are cold resistant i.e. they do not depolymerize at 0°C. Moreover these microtubules did not depolymerize even in the presence of 5 mM CaCl2 or 50 ?M colchicine. These interesting findings may explain how larvae in the free living stages may survive cold temperatures over winter. PMID:24525483

Ashraf, Shoaib; Prichard, Roger K

2014-01-01

327

Nuclear Winter: The Continuing Debate.  

National Technical Information Service (NTIS)

This essay examines the debate over the climatic consequences of global nuclear war as related in the so-called Nuclear Winter hypothesis. the review examines the major components of the theory and traces development of the scientific knowledge leading to...

A. V. Nida

1987-01-01

328

Learners in Action, Winter 2006  

ERIC Educational Resources Information Center

This Winter 2006 issue of "Learners in Action" contains the following articles: (1) Premiers Honour Adult Learners; (2) Learning Difficulties?; (3) Awards; (4) Hats off to Jacques Demers!; (5) What Do You Think?; (6) Meet the Current Learners Advisory Network; and (7) "Learning Edge" is No Ordinary Magazine!.

Movement for Canadian Literacy, 2006

2006-01-01

329

Learning through a Winter's Tale  

ERIC Educational Resources Information Center

In this article, the author shares her experience during the final semester of Year 11 Theatre Studies when she performed a monologue about Hermione from "The Winter's Tale". This experience was extremely significant to her because it nearly made her lose faith in one of the most important parts of her life, drama. She believes this experience,…

Vidotto, Kristie

2010-01-01

330

Nonlinear effects of climate on boreal rodent dynamics: mild winters do not negate high-amplitude cycles.  

PubMed

Small rodents are key species in many ecosystems. In boreal and subarctic environments, their importance is heightened by pronounced multiannual population cycles. Alarmingly, the previously regular rodent cycles appear to be collapsing simultaneously in many areas. Climate change, particularly decreasing snow quality or quantity in winter, is hypothesized as a causal factor, but the evidence is contradictory. Reliable analysis of population dynamics and the influence of climate thereon necessitate spatially and temporally extensive data. We combined data on vole abundances and climate, collected at 33 locations throughout Finland from 1970 to 2011, to test the hypothesis that warming winters are causing a disappearance of multiannual vole cycles. We predicted that vole population dynamics exhibit geographic and temporal variation associated with variation in climate; reduced cyclicity should be observed when and where winter weather has become milder. We found that the temporal patterns in cyclicity varied between climatically different regions: a transient reduction in cycle amplitude in the coldest region, low-amplitude cycles or irregular dynamics in the climatically intermediate regions, and strengthening cyclicity in the warmest region. Our results did not support the hypothesis that mild winters are uniformly leading to irregular dynamics in boreal vole populations. Long and cold winters were neither a prerequisite for high-amplitude multiannual cycles, nor were mild winters with reduced snow cover associated with reduced winter growth rates. Population dynamics correlated more strongly with growing season than with winter conditions. Cyclicity was weakened by increasing growing season temperatures in the cold, but strengthened in the warm regions. High-amplitude multiannual vole cycles emerge in two climatic regimes: a winter-driven cycle in cold, and a summer-driven cycle in warm climates. Finally, we show that geographic climatic gradients alone may not reliably predict biological responses to climate change. PMID:23504828

Korpela, Katri; Delgado, Maria; Henttonen, Heikki; Korpimäki, Erkki; Koskela, Esa; Ovaskainen, Otso; Pietiäinen, Hannu; Sundell, Janne; Yoccoz, Nigel G; Huitu, Otso

2013-03-01

331

Deadly Cold: Health Hazards Due to Cold Weather. An Information Paper by the Subcommittee on Health and Long-Term Care of the Select Committee on Aging. House of Representatives, Ninety-Eighth Congress, Second Session (February 1984).  

ERIC Educational Resources Information Center

This paper, on the health hazards of cold weather for elderly persons, presents information from various sources on the death rates in winter throughout the United States. After reviewing the scope of the problem, specific health hazards associated with cold weather are discussed, i.e., hypothermia, fires, carbon monoxide poisoning, and influenza…

Congress of the U.S., Washington, DC. House Select Committee on Aging.

332

Intraseasonal Cold Air Outbreak over East Asia and the preceding atmospheric condition over the Barents-Kara Sea  

NASA Astrophysics Data System (ADS)

Frequent occurrence of cold air outbreak is a dominant feature of the East Asian winter monsoon. A contributing factor for the this cold air outbreak is the role of stationary Rossby waves over the Eurasian continent which intensifies the surface Siberian High and the accompanying cold air outflow. Reduced sea ice and increase in turbulence heat flux is hypothesized as a source of such stationary waves (Honda et al. 2009). In particular, the winter of 2009/2010 saw a strong correlation of high pressure anomaly over the Barents/Kara sea and the following cold air buildup over the Eurasian continent and its advection towards East Asia (Hori et al. 2011). The lag correlation of surface temperature over Japan and the 850hPa geopotential height shows a cyclonic anomaly appearing over the Barents/Kara sea which creates a cold air advection over the Eurasian continent. The pressure anomaly subsequently shifted westward to mature into a blocking high which created a wave- train pattern downstream advecting the cold air buildup eastward toward East Asia and Japan (Fig1). We further examine this mechanism for other years including the 2005/2006, 2010/2011 winter and other winters with extreme cold air outbreaks. Overall, the existence of an anticyclonic anomaly over the Barents/Kara sea correlated well with the seasonal dominance of cold air over the Eurasian continent thereby creating a contrast of a warm Arctic and cold Eurasian continent.In the intraseasonal timescale, the existence of this anticyclone corresponds to a persisting atmospheric blocking in the high latitudes. In the presentation, we address the underlying chain of events leading up to a strong cold air outbreak over East Asia from an atmosphere - sea ice - land surafce interaction point of view for paritular cold winter years.

Hori, M. E.; Inoue, J.

2011-12-01

333

The contribution of Alaskan, Siberian, and Canadian coastal polynyas to the cold halocline layer of the Arctic Ocean  

Microsoft Academic Search

Numerous Arctic Ocean circulation and geochemical studies suggest that ice growth in polynyas over the Alaskan, Siberian, and Canadian continental shelves is a source of cold, saline water which contributes to the maintenance of the Arctic Ocean halocline. The purpose of this study is to estimate for the 1978-1987 winters the contributions of Arctic coastal polynyas to the cold halocline

Donald J. Cavalieri; Seelye Martin

1994-01-01

334

Identification of genes associated with cold acclimation in blueberry ( Vaccinium corymbosum L.) using a subtractive hybridization approach  

Microsoft Academic Search

Enhanced cold tolerance, including tolerance to winter freezing and spring frosts, is needed for genetic improvement of current highbush blueberry (Vaccinium corymbosum L.) cultivars. To gain a better understanding of changes in gene expression associated with development of cold tolerance in blueberry and other woody perennials, forward and reverse subtracted cDNA libraries were prepared in such a way to enrich

Dhananjay Naik; Anik L. Dhanaraj; Rajeev Arora; Lisa J. Rowland

2007-01-01

335

Unusual Southern Hemisphere Stratosphere Winter of 2002.  

National Technical Information Service (NTIS)

The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course o...

P. A. Newman E. R. Nash

2003-01-01

336

Winter Operations-Abrasives and Salt Brine.  

National Technical Information Service (NTIS)

The primary objective of winter maintenance operations is to improve traffic safety and efficiency during winter storm periods. Abrasives and salt brines have been successfully applied to increase traction and prevent snow and ice from bonding to road sur...

G. Pesti Y. Liu

2003-01-01

337

Cold fusion: Alchemist's dream  

NASA Astrophysics Data System (ADS)

In this report the following topics relating to cold fusion are discussed: muon catalyzed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalyzed cold fusion; vibrational mechanisms in excited states of D2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D2 fusion at low energies; fusion of deuterons into He-4; secondary D+T fusion within the hydrogenated metal lattice; helium-3 to helium-4 ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of helium-3/helium-4.

Clayton, E. D.

1989-09-01

338

Effects of weather on habitat selection and behavior of mallards wintering in Nebraska  

USGS Publications Warehouse

Sex and age ratios, habitat selection, spatial characteristics, and time budgets of Mallards (Anas platyrhynchos) wintering on the Platte River in south central Nebraska were studied from mid-December to early April 1978-1980. The proportion of females and subadults in the population increased substantially from a cold to a mild winter. Radio-tagged Mallards shifted from riverine to canal roost sites during the coldest periods of the winter, seemingly because of more favorable microclimatic conditions there. Subadults ranged over larger areas during winter than did adults. Activity patterns varied with weather conditions, time of day, and habitat type. During cold periods, energetically costly activities such as aggression and courtship decreased at roost sites and the intensity of foraging activities in fields increased. Mallards were more active at riverine than canal sites during both years. High energy requirements and intense competition for scarce food appear to be primary factors limiting the northernmost distribution of Mallards in winter and causing their skewed sex and age ratios.

Jorde, D. G.; Krapu, G. L.; Crawford, R. D.; Hay, M. A.

1984-01-01

339

Britannica Sporting Record: The Winter Games  

NSDL National Science Digital Library

Encyclopaedia Britannica's Olympic Winter Games site offers detailed Olympic information and history. Offerings include an overview of the Olympic movement, histories of each of the past seventeen Olympic Winter Games, articles about the events included in the Winter Games, biographies of past competitors, and a searchable Olympic Record database. This well-researched site provides an interesting backdrop for this year's Winter Games in Nagano, Japan.

Encyclopaedia Britannica, Inc.

1998-01-01

340

Disquiet on the eastern front  

Microsoft Academic Search

Even in this more relaxed post-Cold War era, Russia`s leaders believe that nuclear weapons are vital to national security. Maintaining confidence in their safety, security, and reliability is therefore essential. But whether Russia can maintain the necessary level of confidence in the face of economic chaos is uncertain. The Russian nuclear weapons complex, managed by the Ministry of Atomic Energy

Bukharin

1997-01-01

341

Numerical Simulation of Thunderstorm Gust Fronts.  

National Technical Information Service (NTIS)

The thunderstorm gust front is an important feature for both the maintenance and initiation of storms. Previous studies have shown that the thunderstorm outflow producing the gust front can be treated as an atmospheric density current to a good approximat...

K. L. Seitter

1983-01-01

342

Light-Front Quantization of Gauge Theories.  

National Technical Information Service (NTIS)

Light-front wavefunctions provide a frame-independent representation of hadrons in terms of their physical quark and gluon degrees of freedom. The light-front Hamiltonian formalism provides new nonperturbative methods for obtaining the QCD spectrum and ei...

S. J. Brodsky

2003-01-01

343

1992 AGU Front Range Meeting  

NASA Astrophysics Data System (ADS)

The AGU Front Range Branch held its annual meeting on February 10, 1992, at the National Center for Atmospheric Research in Boulder, Colo. The theme of the meeting was “Our Changing Environment,” with specific emphasis on the Rocky Mountains, the Front Range, the High Plains, and the Great Basin environments.The all-day meeting featured twenty oral presentations and five poster presentations. Most of the topics presented were related to environmental issues such as ozone depletion, emergency response applications at the Rocky Flats Plant, climatic forcing, and hydrogeology. Other papers of interest included a geophysical study of the Sand Dunes National Monument in Colorado, a paper on the impact of the 1988 forest fires on the chemistry of nonthermal groundwater at Yellowstone National Park, and a poster on the soil-gas flux of carbon dioxide from nonventing areas of the Kilauea Summit in Hawaii. A poster and an oral presentation centered on the vulnerability of transportation and energy supply networks in the central United States to earthquakes in the New Madrid seismic zone. The field of space science was represented by two posters on recent geomagnetic behaviors and magnetospheric convection and an oral presentation on plasma density in the Earth's magnetosphere. Three Front Range Branch awards were given to students to recognize excellent presentations.

Rush, Sandra

344

Leadership in American Indian Communities: Winter Lessons  

ERIC Educational Resources Information Center

Winter lessons, or stories told in the winter, were one of the ways in which tribal elders instructed and directed young men and women in the proper ways to assume leadership responsibilities. Winter lessons stressed the appropriate relationship between the leader and the community. The intent was to remember the power and purpose of that…

Metoyer, Cheryl A.

2010-01-01

345

Trends of cold and heat waves in Serbia  

NASA Astrophysics Data System (ADS)

The series of the daily minimum and maximum temperatures at fifteen stations in Serbia were used to calculate the cold and warm spell duration indicators, from which the duration and severity of the cold and heat waves were estimated. The trend analysis for all seasons was presented using the data from 1949 to 2012. The most important result of this study is the significant decreasing trends in the frequency of cold waves and increasing trends of heat waves in Serbia. An analysis of the daily minimum temperatures almost at all meteorological stations revealed that the longest and most severe cold waves were observed in winter of 1956, spring of 1987, summer of 1962 and 1996, and during the autumn 1983 and 1988. The longest and most severe heat waves, based on the analysis of the daily maximum temperatures, were recorded in winter of 2007, spring of 2003, summer of 2012, and after 1989 during the autumn. The longest heat waves observed in 2012 did not reach the severity of the heat waves in 2007 at ten of fifteen stations. The obtained results indicated that the warming in Serbia was more related to increase in frequency of heat waves than to reduction in cold waves.

Unkaševi?, Miroslava; Toši?, Ivana

2014-05-01

346

Arctic winter 2009/2010 and 2010/2011 in comparison: Denitrification and polar stratospheric cloud formation  

NASA Astrophysics Data System (ADS)

Polar Stratospheric Clouds (PSCs) and denitrification, the permanent removal of nitric acid (HNO3) by sedimenting HNO3 containing PSC particles, play a key role in stratospheric ozone depletion. The two recent Arctic winter 2009/2010 and 2010/2011 were both quite unique. The Arctic winter 2010/2011 was one of the coldest winter on record leading to the strongest depletion of ozone ever measured. Though the Arctic winter 2009/2010 was rather warm in the climatological sense it was distuinguished by a exceptionally cold stratosphere from mid December 2009 to mid January 2010 leading to prolonged PSC formation and strong denitrification. For investigating PSC formation during these two Arctic winter we apply ground-based measurements performed with the Esrange and the IRF lidar in the area of Kiruna, Northern Sweden (69° N 21° E) and space-borne lidar measurements from the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) Satellite together with microphysical box model simulations. To investigate denitrification during these two Arctic winter we apply measurements from the Odin Sub-Millimetre Radiometer (Odin/SMR) as well as measurements from the Microwave Limb Sounder on Aura (Aura/MLS). Though denitrification in 2009/2010 was until then the strongest in the entire Odin/SMR measurement period it was excelled by the 2010/2011 winter where denitrification was nearly as severe as in the Antarctic. PSC occurrance during both winter was also quite different. While PSCs were present during the Arctic winter 2010/2011 over nearly four months, from mid December to end of March, they were not as persistent as the ones that occurred during the shorter (one month) cold period during the Arctic winter 2009/2010.

Khosrawi, F.; Urban, J.; Pitts, M. C.; Voelger, P.; Achtert, P.; Santee, M. L.; Manney, G. L.; Murtagh, D.

2012-04-01

347

Southern Ocean fronts from the Greenwich meridian  

Microsoft Academic Search

All available meridional sections have been analyzed to investigate the evolution of main fronts between 0 ø and 150øE. The central South Atlantic is featured by the Subtropical Frontal Zone (STFZ), bordered by the North and South Subtropical Fronts (NSTF and SSTF, respectively), and by the Polar Frontal Zone (PFZ), bordered by the Subantarctic and Polar Fronts (SAF and PF,

Igor M. Belkin

1996-01-01

348

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.  

Code of Federal Regulations, 2010 CFR

... 1 2010-07-01 2010-07-01 false Winter Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section 100.109...SAFETY OF LIFE ON NAVIGABLE WATERS § 100.109 Winter Harbor Lobster Boat Race, Winter Harbor,...

2010-07-01

349

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.  

Code of Federal Regulations, 2010 CFR

... 1 2009-07-01 2009-07-01 false Winter Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section 100.109...SAFETY OF LIFE ON NAVIGABLE WATERS § 100.109 Winter Harbor Lobster Boat Race, Winter Harbor,...

2009-07-01

350

Nesting habitat of the Tule Greater White-fronted Goose Anser albifrons elgasi  

USGS Publications Warehouse

This paper presents the first information on the availability and use of nesting habitat by the rare Tule Greater White-fronted Goose Anser albifrons elgasi. The breeding range was sampled by marking geese with radio transmitters on wintering and moulting areas, and tracking them to nest sites in Alaska. Nesting habitat was described at the scales of ecoregion, wetland ecosystem (National Wetlands Inventory (NWI) maps), vegetation type within wetland (Alaska Vegetation Classification (AVC) maps based on satellite imagery), and nest site. Tule Greater White-fronted Goose nests were located in boreal forest wetlands in the upper Cook Inlet Basin ecoregion. Nesting Tule Greater White-fronted Geese selected NWT Palustrine Seasonally Flooded wetlands and used NWI Palustrine Saturated wetlands in proportion to availability. Within these wetlands, Tule Greater White-fronted Geese used Needleleaf Forest, Low Shrub and Herbaceous (mostly graminoid) AVC classes for nest sites in proportion to availability Most (93%) Tule Greater White-fronted Geese nested > 75 m from open water ponds or lakes, and many nested in wetlands with little or no open water. Tule Greater White-fronted Geese nest only in a small breeding area near the most human-impacted area of the state, and continued development may limit the use of suitable nesting habitat.

Densmore, R. V.; Ely, C. R.; Bollinger, K. S.; Kratzer, S.; Udevitz, M. S.; Fehringer, D. J.; Rothe, T. C.

2006-01-01

351

High cold tolerance through four seasons and all free-living stages in an ectoparasite.  

PubMed

Off-host stages of temperate parasites must cope with low temperatures. Cold tolerance is often highest in winter, as a result of diapause and cold acclimation, and low during the active summer stages. In some blood-feeding ectoparasites, offspring provisioning determines cold tolerance through all the non-feeding, off-host stages. Large size increases survival in the cold, but so far seasonal variation in within-female offspring size has not been associated with offspring cold tolerance. The deer ked (Lipoptena cervi) reproduces on cervids from autumn to spring. Newborn pupae drop off the host, facing frosts without any acclimation. We examined cold tolerance through 4 seasons and from birth to adulthood by means of short- and long-term frost exposure. We expected females to produce more tolerant offspring in winter than in spring. Large spring pupae survived prolonged frosts better than did small winter pupae. Thus more tolerant offspring were not produced when the temperature outside the host is at its lowest. Unexpectedly, the freezing points were -20 °C or below all year round. We showed that high cold tolerance is possible without acclimation regardless of life stage, which presumably correlates with other survival characteristics, such as the starvation resistance of free-living ectoparasites. PMID:22313619

Härkönen, Laura; Kaitala, Arja; Kaunisto, Sirpa; Repo, Tapani

2012-06-01

352

Evaporation fronts in porous media  

NASA Astrophysics Data System (ADS)

Experimental and computational studies have been conducted to model the propagation of evaporating fronts through porous media. The results from the experiments are compared with a numerical model and the results agree qualitatively with the temperature distribution in the vapor and liquid regions obtained from the numerical solution. The condition for which a two-phase zone does not exist due to high heat flux is also examined. Results also confirm earlier analysis of the front stability. In this thesis an implicit finite difference scheme is utilized to simulate the propagation of an evaporating front in a porous medium saturated with water and undergoing the phase change process. The following three numerical models are developed: (1) a one-equation model that assumes local thermal equilibrium; (2) a two-equation model that utilizes the lumped capacitance assumption to predict the heat transfer to the solid phase; and (3) a two-equation model that utilizes a more precise quasi-analytical approach to more accurately characterize the conduction in the solid phase. Results illustrate that the one-equation model does not yield accurate results when the thermophysical properties characterized by the volume weighted ratio of thermal diffusivities, C, is greater than 10 (within 5% error). Hence a two-equation model is necessary depending on the level of accuracy desired. In addition, consistent with the established "rule of thumb", for Biot number, Biv, is less than 0.1, the traditional two-equation model which makes the lumped capacitance assumption for the solid phase compares well with a two-equation model that more accurately predicts the time dependent diffusion in the solid phase using Duhamel's theorem. High intensity drying is used to characterize those situations for which the drying medium is sufficiently above the saturation temperature of water to preclude the existence of a two-phase zone. High intensity drying is modeled numerically and the relationship between pressure, the drying conditions and material properties is examined since elevated pressure that can occur during high intensity drying is potentially destructive. A quasi two-dimensional numerical model of high intensity drying with specific application to underground coal gasification is presented. The anisotropy due to permeability of coal is considered and the results illustrate that a decrease in permeability, K (10-14 to 10-12 m2), results in faster front propagation. Front propagation for the same thick coal seam at two different depths indicated that it is faster when the depth increases. It was also found that as the thickness of coal seam decreases the front propagates faster. Decreasing the pressure or increasing the temperature in the cavity results in a faster front propagation. Groundwater contamination can be a potential problem when the pressure and temperature in the cavity are lowered.

Pakala, Venkata Krishna Chaitanya

353

How cold pool triggers deep convection?  

NASA Astrophysics Data System (ADS)

The cold pool in the boundary layer is often considered a major triggering mechanism of convection. Here, presented are basic theoretical considerations on this issue. Observations suggest that cold pool-generated convective cells is available for shallow maritime convection (Warner et al. 1979; Zuidema et al. 2012), maritime deep convection (Barnes and Garstang 1982; Addis et al. 1984; Young et al. 1995) and continental deep convection (e.g., Lima and Wilson 2008; Flamant 2009; Lothon et al. 2011; Dione et al. 2013). Moreover, numerical studies appear to suggest that cold pools promote the organization of clouds into larger structures and thereby aid the transition from shallow to deep convection (Khairoutdinov and Randall 2006, Boing et al. 2012, Schlemmer and Hohenegger, 2014). Even a cold--pool parameterization coupled with convection is already proposed (Grandpeix and Lafore 2010: but see also Yano 2012). However, the suggested link between the cold pool and deep convection so far is phenomenological at the best. A specific process that the cold pool leads to a trigger of deep convection must still to be pinned down. Naively, one may imagine that a cold pool lifts up the air at the front as it propagates. Such an uplifting leads to a trigger of convection. However, one must realize that a shift of air along with its propagation does not necessarily lead to an uplifting, and even if it may happen, it would not far exceed a depth of the cold pool itself. Thus, the uplifting can never be anything vigorous. Its thermodynamic characteristics do help much either for inducing convection. The cold-pool air is rather under rapid recovering process before it can induce convection under a simple parcel-lifting argument. The most likely reason that the cold pool may induce convection is its gust winds that may encounter an air mass from an opposite direction. This induces a strong convergence, also leading to a strong uplifting. This is an argument essentially developed by Moncrieff and Liu (1999). As a whole, in attempting a statistical description of boundary-layer processes, the cold pool is essentially nothing other than an additional contribution to a TKE (turbulent kinetic energy) budget. Significance of trigger of convection by cold pool in context of convection parameterization must also be seen with much caution. Against a common misunderstanding, current convection parameterization is not designed to describe a trigger process of individual convection. In this respect, process studies on cold pool do not contribute to improvements of convection parameterization until a well-defined parameterization formulation for individual convection processes is developed. Even before then a question should also be posed whether such a development is necessary. Under a current mass-flux convection parameterization, a more important process to consider is re-evaporative cooling of detrained cloudy air, which may also be associated with downdraft, possibly further leading to a generation of a cold pool. Yano and Plant (2012) suggest, from a point of view of the convective-energy cycle, what follows would be far less important than the fact the re-evaporation induces a generation of convective kinetic energy (though it may initially be considered TKE). Both well-focused convective process studies as well as convection parameterization formulation would be much needed.

Yano, Jun-Ichi

2014-05-01

354

Excess winter mortality in Europe: a cross country analysis identifying key risk factors  

PubMed Central

Objective: Much debate remains regarding why certain countries experience dramatically higher winter mortality. Potential causative factors other than cold exposure have rarely been analysed. Comparatively less research exists on excess winter deaths in southern Europe. Multiple time series data on a variety of risk factors are analysed against seasonal-mortality patterns in 14 European countries to identify key relations Subjects and setting: Excess winter deaths (all causes), 1988–97, EU-14. Design: Coefficients of seasonal variation in mortality are calculated for EU-14 using monthly mortality data. Comparable, longitudinal datasets on risk factors pertaining to climate, macroeconomy, health care, lifestyle, socioeconomics, and housing were also obtained. Poisson regression identifies seasonality relations over time. Results: Portugal suffers from the highest rates of excess winter mortality (28%, CI=25% to 31%) followed jointly by Spain (21%, CI=19% to 23%), and Ireland (21%, CI=18% to 24%). Cross country variations in mean winter environmental temperature (regression coefficient (ß)=0.27), mean winter relative humidity (ß=0.54), parity adjusted per capita national income (ß=1.08), per capita health expenditure (ß=-1.19), rates of income poverty (ß=-0.47), inequality (ß=0.97), deprivation (ß=0.11), and fuel poverty (ß=0.44), and several indicators of residential thermal standards are found to be significantly related to variations in relative excess winter mortality at the 5% level. The strong, positive relation with environmental temperature and strong negative relation with thermal efficiency indicate that housing standards in southern and western Europe play strong parts in such seasonality. Conclusions: High seasonal mortality in southern and western Europe could be reduced through improved protection from the cold indoors, increased public spending on health care, and improved socioeconomic circumstances resulting in more equitable income distribution.

Healy, J

2003-01-01

355

Water masses, ocean fronts, and the structure of Antarctic seabird communities: Putting the eastern Bellingshausen Sea in perspective  

USGS Publications Warehouse

Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April-September) and summer (October-March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Ad??lie penguins (. Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group dominated by Ad??lie penguins, a Low Antarctic group dominated by petrels, and a Subantarctic group dominated by albatross were evident. In eastern Bellingshausen waters during summer, groups were inconsistent. With regard to frontal features, Antarctic-wide in winter, distance to the ice edge was an important explanatory factor for nine of 14 species, distance to the Antarctic Polar Front for six species and distance to the Shelf Break Front for six species; however, these Antarctic-wide models could not successfully predict spatial relationships of winter seabird density (individual species or total) and biomass in the eastern Bellingshausen. Antarctic-wide in summer, distance to land/Antarctic continent was important for 10 of 18 species, not a surprising result for these summer-time Antarctic breeders, as colonies are associated with ice-free areas of coastal land. Distance to the Shelf Break Front was important for 8 and distance to the southern boundary of the ACC was important for 7 species. These summer models were more successful in predicting eastern Bellingshausen species density and species diversity but failed to predict total seabird density or biomass. Antarctic seabirds appear to respond to fronts in a way similar to that observed along the well-studied upwelling front of the California Current. To understand fully the seabird patterns found in this synthesis, multi-disciplinary at-sea investigations, including a quantified prey field, are needed. ?? 2011.

Ribic, C. A.; Ainley, D. G.; Glenn, Ford, R.; Fraser, W. R.; Tynan, C. T.; Woehler, E. J.

2011-01-01

356

Informing the Front Line about Common Respiratory Viral Epidemics  

PubMed Central

The nature of clinical medicine is to focus on individuals rather than the populations from which they originate. This orientation can be problematic in the context of acute healthcare delivery during routine winter outbreaks of viral respiratory disease where an individual’s likelihood of viral infection depends on knowledge of local disease incidence. The level of interest in and perceived utility of community and regional infection data for front line clinicians providing acute care is unclear. Based on input from clinicians, we developed an automated analysis and reporting system that delivers pathogen-specific epidemic curves derived from a viral panel that tests for influenza, RSV, adenovirus, parainfluenza and human metapneumovirus. Surveillance summaries were actively e-mailed to clinicians practicing in emergency, urgent and primary care settings and posted on a web site for passive consumption. We demonstrated the feasibility and sustainability of a system that provides both timely and clinically useful surveillance information.

Gesteland, Per H; Samore, Matthew H; Pavia, Andrew T; Srivastava, Rajendu; Korgenski, Kent; Gerber, Kristine; Daly, Judy A; Mundorff, Michael B; Rolfs, Robert T; James, Brent C.; Byington, Carrie L.

2007-01-01

357

Ice-dependent winter survival of juvenile Atlantic salmon.  

PubMed

Changes in snow and ice conditions are some of the most distinctive impacts of global warming in cold temperate and Arctic regions, altering the environment during a critical period for survival for most animals. Laboratories studies have suggested that reduced ice cover may reduce the survival of stream dwelling fishes in Northern environments. This, however, has not been empirically investigated in natural populations in large rivers. Here, we examine how the winter survival of juvenile Atlantic salmon in a large natural river, the River Alta (Norway, 70°N), is affected by the presence or absence of surface ice. Apparent survival rates for size classes corresponding to parr and presmolts were estimated using capture-mark-recapture and Cormack-Jolly-Seber models for an ice-covered and an ice-free site. Apparent survival (?) in the ice-covered site was greater than in the ice-free site, but did not depend on size class (0.64 for both parr and presmolt). In contrast, apparent survival in the ice-free site was lower for larger individuals (0.33) than smaller individuals (0.45). The over-winter decline in storage energy was greater for the ice-free site than the ice-covered site, suggesting that environmental conditions in the ice-free site caused a strong depletion in energy reserves likely affecting survival. Our findings highlight the importance of surface ice for the winter survival of juvenile fish, thus, underpinning that climate change, by reducing ice cover, may have a negative effect on the survival of fish adapted to ice-covered habitats during winter. PMID:23532172

Hedger, R D; Næsje, T F; Fiske, P; Ugedal, O; Finstad, A G; Thorstad, E B

2013-03-01

358

Ice-dependent winter survival of juvenile Atlantic salmon  

PubMed Central

Changes in snow and ice conditions are some of the most distinctive impacts of global warming in cold temperate and Arctic regions, altering the environment during a critical period for survival for most animals. Laboratories studies have suggested that reduced ice cover may reduce the survival of stream dwelling fishes in Northern environments. This, however, has not been empirically investigated in natural populations in large rivers. Here, we examine how the winter survival of juvenile Atlantic salmon in a large natural river, the River Alta (Norway, 70°N), is affected by the presence or absence of surface ice. Apparent survival rates for size classes corresponding to parr and presmolts were estimated using capture-mark-recapture and Cormack-Jolly-Seber models for an ice-covered and an ice-free site. Apparent survival (?) in the ice-covered site was greater than in the ice-free site, but did not depend on size class (0.64 for both parr and presmolt). In contrast, apparent survival in the ice-free site was lower for larger individuals (0.33) than smaller individuals (0.45). The over-winter decline in storage energy was greater for the ice-free site than the ice-covered site, suggesting that environmental conditions in the ice-free site caused a strong depletion in energy reserves likely affecting survival. Our findings highlight the importance of surface ice for the winter survival of juvenile fish, thus, underpinning that climate change, by reducing ice cover, may have a negative effect on the survival of fish adapted to ice-covered habitats during winter.

Hedger, R D; Naesje, T F; Fiske, P; Ugedal, O; Finstad, A G; Thorstad, E B

2013-01-01

359

Cold adaptation in the phytopathogenic fungi causing snow molds  

Microsoft Academic Search

Snow molds are psychrophilic or psychrotrophic fungal pathogens of forage crops, winter cereals, and conifer seedlings. These\\u000a fungi can grow and attack dormant plants at low temperatures under snow cover. In this review, we describe the biodiversity\\u000a and physiological and biochemical characteristics of snow molds that belong to various taxa. Cold tolerance is one of the\\u000a important factors related to

Tamotsu Hoshino; Nan Xiao; Oleg B. Tkachenko

2009-01-01

360

Crack front dynamics across a single heterogeneity.  

PubMed

We study the spatiotemporal dynamics of a crack front propagating at the interface between a rigid substrate and an elastomer. We first characterize the kinematics of the front when the substrate is homogeneous and find that the equation of motion is intrinsically nonlinear. We then pattern the substrate with a single defect. Steady profiles of the front are well described by a standard linear theory with nonlocal elasticity, except for large slopes of the front. In contrast, this theory seems to fail in dynamical situations, i.e., when the front relaxes to its steady shape, or when the front pinches off after detachment from a defect. More generally, these results may impact the current understanding of crack fronts in heterogeneous media. PMID:22107197

Chopin, J; Prevost, A; Boudaoud, A; Adda-Bedia, M

2011-09-30

361

Crack Front Dynamics across a Single Heterogeneity  

NASA Astrophysics Data System (ADS)

We study the spatiotemporal dynamics of a crack front propagating at the interface between a rigid substrate and an elastomer. We first characterize the kinematics of the front when the substrate is homogeneous and find that the equation of motion is intrinsically nonlinear. We then pattern the substrate with a single defect. Steady profiles of the front are well described by a standard linear theory with nonlocal elasticity, except for large slopes of the front. In contrast, this theory seems to fail in dynamical situations, i.e., when the front relaxes to its steady shape, or when the front pinches off after detachment from a defect. More generally, these results may impact the current understanding of crack fronts in heterogeneous media.

Chopin, J.; Prevost, A.; Boudaoud, A.; Adda-Bedia, M.

2011-09-01

362

Benefits of front brakes on heavy trucks  

SciTech Connect

This paper addresses the issue of front wheel braking on heavy trucks and reviews testing that has been performed over the years dating back to 1948 to evaluate the effect of front brakes on braking performance. It also describes in detail a test and demonstration program on front wheel brakes that was conducted in September 1986. The paper indicates that front wheel brakes have a strong effect on braking performance and that vehicles without front wheel brakes take longer distances to stop and are more likely to lose control in emergency situations. The paper also indicates that the use of front brake pressure limiting valves with typical, current design front brakes degrades vehicle braking performance.

Radlinski, R.W.; Flick, M.A.

1987-01-01

363

Interannual variation of East Asian Winter Monsoon and ENSO  

SciTech Connect

This paper examines the interannual variation of the East Asian winter monsoon and its relationship with EJSO based on the 1979-1995 NCEP/NCAR reanalysis. Two stratifications of cold surges are used. The first one, described as the conventional cold surges, indicates that the surge frequency reaches a urn one year after El Nino events. The second one, originated from the same region as the first, is defined as the maximum wind events near the South China Sea. The variation of this stratification of surges is found to be in good agreement with the South Oscillation Index (SOI). Low SOI (high SOI) events coincide with years of low (high) surge frequency. The interannual variation of averaged meridional wind near the South China Sea and western Pacific is dominated by the South China Sea cold surges, and is also well correlated (R--O.82) with the SOI. Strong wind seasons are associated with La Nina and high SOI events; likewise, weak wind years are linked with El Nino and low SOI cases. This pattern is restricted north of the equator within the region of (OON-20 N, 11OOE-1300E), and is confined to the near surface layer. The surface Siberian high, 500 hPa trough and 200 hPa jetstream, all representing the large-scale monsoon flow, are found to be weaker than normal during El Nino years. In particular, the interannual variation of the Siberian high is in general agreement with the SOL.

Zhang, Yi; Sperber, Kenneth R.; Boyle, James S.

1996-12-01

364

Study of formation process of cold intermediate layer based on reanalysis of Black Sea hydrophysical fields for 1971-1993  

NASA Astrophysics Data System (ADS)

A reanalysis of hydrophysical fields for 1971-1993 is used to study the formation mechanisms of the cold intermediate layer (CIL): the advective mechanism (associated with the advection of cold waters formed in the northwestern shelf (NWS)) and the convective mechanism (caused by wintertime convection inside cyclonic gyres in the central part of the sea). We consider the periods of alternating atmospheric conditions: the mild winter of 1980-1981, normal winter of 1987-1988, and cold winter of 1992-1993. Interannual features of replenishment and renewal of "old" CIL waters caused by these mechanisms are identified. In particular, cooled shelf waters sink along the continental slope and merge with "old" CIL waters during the mild winter of 1980-1981 more than 1 month later than during the cold winter 1992-1993 and more than 3 weeks later than during the normal winter of 1987-1988. The Sevastopol anticyclonic gyre and the northwest branch of the Black Sea Rim Current markedly influence the transformation of entrained cold NWS waters transported to the southwest and the central part of the water area. The local formation process of cold intermediate waters is found to be caused by the wintertime penetrating convection over domelike isosurfaces of temperature and salinity arising due to rising constant halocline (pycnocline) at the centers of cyclonic gyres because of the intensification of the wintertime circulation. Anomalously cold surface water, characterized by increased density, gradually sinks. An analysis of TS indices indicates that the transformed cold water spreads out over isopycnic surfaces with time, being entrained in cyclonic circulation and spreading throughout the sea, thus renewing "old" CIL waters.

Korotaev, G. K.; Knysh, V. V.; Kubryakov, A. I.

2014-01-01

365

Communicating Certainty About Nuclear Winter  

NASA Astrophysics Data System (ADS)

I have been spending much of my time in the past several years trying to warn the world about the continuing danger of nuclear weapons, and that the solution is a rapid reduction in the nuclear arsenal. I feel that a scientist who discovers dangers to society has an ethical duty to issue a warning, even if the danger is so scary that it is hard for people to deal with. The debate about nuclear winter in the 1980s helped to end the nuclear arms race, but the planet still has enough nuclear weapons, even after reductions planned for 2017 under the New START treaty, to produce nuclear winter, with temperatures plunging below freezing in the summer in major agricultural regions, threatening the food supply for most of the planet. New research by myself, Brian Toon, Mike Mills, and colleagues over the past six years has found that a nuclear war between any two countries, such as India and Pakistan, using 50 atom bombs each of the size dropped on Hiroshima could produce climate change unprecedented in recorded human history, and a world food crisis because of the agricultural effects. This is much less than 1% of the current global arsenal. Communicating certainty - what we know for sure - has been much more effective than communicating uncertainty. The limited success I have had has come from persistence and serendipity. The first step was to do the science. We have published peer-reviewed articles in major journals, including Science, Nature, Proceedings of the National Academy of Sciences, Journal of Geophysical Research, Atmospheric Chemistry and Physics, Physics Today, and Climatic Change. But policymakers do not read these journals. Through fairly convoluted circumstances, which will be described in this talk, we were able to get papers published in Scientific American and the Bulletin of Atomic Scientists. I have also published several encyclopedia articles on the subject. As a Lead Author of Chapter 8 (Radiative Forcing) of the recently published Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), I inserted a paragraph pointing out that volcanic eruptions serve as an analog that supports new work on nuclear winter. This is the first time that nuclear winter has been in the IPCC report. I will tell the story of the discussions within our chapter, with review editors, and with the IPCC leadership that resulted in a box in Chapter 8 that discusses nuclear winter. We gave a briefing to John Holdren, the President's Science Advisor, about the work. Daniel Ellsberg, Fidel Castro, and Mikhail Gorbachev found out about our work, and used the results to appeal for nuclear abolition. In 2013 the work was featured at the Conference on the Humanitarian Impact of Nuclear Weapons in Oslo, Norway attended by 132 nations, and I gave a TEDx talk, I published an opinion piece on the CNN website, and I gave an invited public lecture in Nagasaki, Japan, all about the climatic consequences of nuclear war. I am now using Twitter and Facebook to communicate about nuclear winter. The threat that nuclear weapons pose to the planet is a much easier problem to solve than global warming. We need to eliminate nuclear weapons so we have the luxury of working on the global warming problem without the possibility of the existential global threat still posed by the global nuclear arsenal.

Robock, A.

2013-12-01

366

The Influence of Snow-Soil Moisture Flux on Snowpack Metamorphism in Late Winter and Early Spring  

Microsoft Academic Search

The importance of land-atmosphere snow cover feedback in the climate system, water storage and release from snowpacks, and the large land areas covered by snow in the northern hemisphere, are reasons to accurately model late winter and early spring snow metamorphic processes. Snowpack models like SNTHERM predict snow behavior very well during the cold periods but do not adequately capture

Y. C. CHUNG; A. W. ENGLAND

2006-01-01

367

Aspects of the winter predator--prey relationship between sauger and threadfin shad in Watts Bar Reservoir, Tennessee  

Microsoft Academic Search

This study sought to determine the impact of cold-induced mortality and impingement of threadfin shad (Dorsoma petenense) on the food consumption and prey selection of sauger (Stizostedion canadense), and to estimate the ability of sauger to digest meals consumed at low temperatures in winter. Prey selection of sauger was monitored from November 1976 through April 1977. Stomach contents of 536

M. V. McGee; J. S. Griffith; R. B. McLean

1978-01-01

368

Observations of Snow Water Equivalent Change on Landfast First-Year Sea Ice in Winter Using Synthetic Aperture Radar Data  

Microsoft Academic Search

In this paper, we examine the utility of synthetic aperture radar (SAR) backscatter data to detect a change in snow water equivalent (SWE) over landfast first-year sea ice during winter at relatively cold temperatures. We begin by reviewing the theoretical framework for linking microwave scattering from SAR to the thermodynamic and electrical properties of first-year sea ice. Previous research has

John J. Yackel; David G. Barber

2007-01-01

369

Hard-coral distribution and cold-water disturbances in South Florida: variation with depth and location  

NASA Astrophysics Data System (ADS)

Line transects were used to sample the structure and diversity of the hermatypic coral community (Scleractinia) on four shallow shelf-edge reefs in South Florida (25° 22'N to 25° 29'N). Low diversities, cover and abundance indicated that this area was a suboptimum habitat for reef-building corals. The lack of acroporids on the shallow fore-reef, the increase in total coral cover with depth and the greater abundance of Montastrea annularis in the deepest zones suggests that cooling of surface water during severe winter cold fronts is a major environmental control on the distribution of hermatypic corals with depth. Such disturbances, occurring more frequently than hurricanes, may preclude the hard-coral community from attaining higher levels of cover and abundance. The shallow zones on the reefs nearest to tidal passes, through which cooled by water enters the reef tract, had the least developed community. In the deeper reef-zones, species richness and abundance increased from north to south over a distance of 13 km.

Burns, T. P.

1985-09-01

370

Winter wheat cells subjected to freezing temperature undergo death process with features of programmed cell death.  

PubMed

Programmed cell death is a process defined as genetically regulated self-destruction or cell suicide. It can be activated by different internal and external factors, but few studies have investigated whether this process occurs under cold and freezing temperatures. In this study, a freezing treatment (-8 °C for 6 h) induced cell death with features of programmed cell death in suspension cultures of winter wheat (Triticum aestivum L.). This process occurred for 10 days after cold exposure. The death of cells in culture was slow and prolonged, and was accompanied by protoplast shrinkage, DNA fragmentation, and an increase in the level of reactive oxygen species. Other changes observed after the freezing treatment included an increase in the respiration rate, changes in mitochondrial transmembrane potential (?? m ), and the release of cytochrome c from mitochondria into the cytosol. These findings indicated that mitochondria are involved in the cell death process that occurs after a freezing treatment in cells of winter wheat. PMID:24126671

Lyubushkina, Irina V; Grabelnych, Olga I; Pobezhimova, Tamara P; Stepanov, Aleksey V; Fedyaeva, Anna V; Fedoseeva, Irina V; Voinikov, Victor K

2014-05-01

371

Investigation of cold colored smoke production  

NASA Astrophysics Data System (ADS)

The main objective of this project is to develop a nonfading colored cold smoke composition for use in a signal cartridge for practice bombs. The primary constraint is that the substance must not require any form of heat to produce the smoke; hence the term cold smoke. The principal use of the colored cold smoke charge is to mark the point of impact of practice bombs used by the Canadian Forces (CF). In summertime, white smoke produced by titanium tetrachloride (TiCl4) is satisfactory; however, colored smoke is required during winter because of the white snow background. Different methods for producing large colored smoke clouds for use as spotting charges are evaluated. The problem of the disappearance, or bleaching, of the orange color from vanadium oxytrichloride (VOCl3) clouds during times of high relative humidity is considered. It is postulated that this is caused by the absorption of large quantities of atmospheric moisture by the smoke. A model has been developed to study the process. This model makes the key predictions concerning the absorption of very large amounts of atmospheric moisture by VOCl3 type smokes above a relative humidity of 80% and the very small importance of temperature as a parameter. These predictions are, in general, corroborated very well by experiment. Possible solutions to this color bleaching problem are discussed, including one that calls for the synthesis of hydrolyzable vanadium compounds with nonhygroscopic leaving groups.

Liberman, T.

1985-08-01

372

Operational forecasting of daily temperatures in the Valencia Region. Part II: minimum temperatures in winter.  

NASA Astrophysics Data System (ADS)

Extreme temperature events have a great impact on human society. Knowledge of minimum temperatures during winter is very useful for both the general public and organisations whose workers have to operate in the open, e.g. railways, roadways, tourism, etc. Moreover, winter minimum temperatures are considered a parameter of interest and concern since persistent cold-waves can affect areas as diverse as public health, energy consumption, etc. Thus, an accurate forecasting of these temperatures could help to predict cold-wave conditions and permit the implementation of strategies aimed at minimizing the negative effects that low temperatures have on human health. The aim of this work is to evaluate the skill of the RAMS model in determining daily minimum temperatures during winter over the Valencia Region. For this, we have used the real-time configuration of this model currently running at the CEAM Foundation. To carry out the model verification process, we have analysed not only the global behaviour of the model for the whole Valencia Region, but also its behaviour for the individual stations distributed within this area. The study has been performed for the winter forecast period from 1 December 2007 - 31 March 2008. The results obtained are encouraging and indicate a good agreement between the observed and simulated minimum temperatures. Moreover, the model captures quite well the temperatures in the extreme cold episodes. Acknowledgement. This work was supported by "GRACCIE" (CSD2007-00067, Programa Consolider-Ingenio 2010), by the Spanish Ministerio de Educación y Ciencia, contract number CGL2005-03386/CLI, and by the Regional Government of Valencia Conselleria de Sanitat, contract "Simulación de las olas de calor e invasiones de frío y su regionalización en la Comunidad Valenciana" ("Heat wave and cold invasion simulation and their regionalization at Valencia Region"). The CEAM Foundation is supported by the Generalitat Valenciana and BANCAIXA (Valencia, Spain).

Gómez, I.; Estrela, M.

2009-09-01

373

The Aleutian Low and Winter Climatic Conditions in the Bering Sea. Part I: Classification  

Microsoft Academic Search

The Aleutian low is examined as a primary determinant of surface air temperature (SAT) variability in the Bering Sea during the winter (December-January-February-March (DJFM)) months. The Classifica- tion and Regression Tree (CART) method is used to classify five types of atmospheric circulation for anomalously warm months (W1-W5) and cold months (C1-C5). For the Bering Sea, changes in the position of

S. N. Rodionov; J. E. Overland; N. A. Bond

2005-01-01

374

Advection from the North Atlantic as the forcing of winter greenhouse effect over Europe  

Microsoft Academic Search

In winter, large interannual fluctuations in the surface temperature are observed over central Europe. Comparing warm February 1990 with cold February 1996, a satellite-retrieved surface (skin) temperature difference of 9.8 K is observed for the region 50-60°N 5-35°E. Previous studies show that advection from the North Atlantic constitutes the forcing to such fluctuations. The advection is quantified by Index Ina,

J. Otterman; J. Angell; R. Atlas; D. Bungato; S. Schubert; D. Starr; J. Susskind; M.-L. C. Wu

2002-01-01

375

Advection from the North Atlantic as the forcing of winter greenhouse effect over Europe  

Microsoft Academic Search

In winter, large interannual fluctuations in the surface temperature are observed over central Europe. Comparing warm February 1990 with cold February 1996, a satellite-retrieved surface (skin) temperature difference of 9.8 K is observed for the region 50–60°N; 5–35°E. Previous studies show that advection from the North Atlantic constitutes the forcing to such fluctuations. The advection is quantified by Index Ina,

J. Otterman; J. Angell; R. Atlas; D. Bungato; S. Schubert; D. Starr; J. Susskind; M.-L. C. Wu

2002-01-01

376

Air-sea fluxes and surface layer turbulence around a sea surface temperature front  

NASA Technical Reports Server (NTRS)

The observed effects of sharp changes in sea surface temperature (SST) on the air-sea fluxes, surface roughness, and the turbulence structure in the surface layer and the marine atmospheric boundary layer are discussed. In situ flux and turbulence observations were carried out from three aircraft and two ships within the FASINEX framework. Three other aircraft used remote sensors to measure waves, microwave backscatter, and lidar signatures of cloud tops. Descriptions of the techniques, intercomparison of aircraft and ship flux data, and use of different methods for analyzing the fluxes from the aircraft data are described. Changing synoptic weather on three successive days yielded cases of wind direction both approximately parallel and perpendicular to a surface temperature front. For the wind perpendicular to the front, wind over both cold-to-warm and warm-to-cold surface temperatures occurred. Model results consistent with the observations suggest that an internal boundary layer forms at the SST.

Friehe, C. A.; Shaw, W. J.; Davidson, K. L.; Rogers, D. P.; Large, W. G.; Stage, S. A.; Crescenti, G. H.; Khalsa, S. J. S.; Greenhut, G. K.; Li, F.

1991-01-01

377

Winter 2009/10: A case study of an extreme Arctic Oscillation event and a skillful climate prediction  

NASA Astrophysics Data System (ADS)

Winter 2009/10 made headlines for extreme cold and snow in most of the major population centers of the industrialized countries of the Northern Hemisphere (NH). The major teleconnection patterns of the Northern Hemisphere, El Niño/Southern Oscillation (ENSO) and the Arctic Oscillation (AO) were of moderate to strong amplitude, making both potentially key players during the winter of 2009/10. The dominant NH winter circulation pattern can be shown to have originated with a two-way stratosphere-troposphere interaction forced by Eurasian land surface and lower tropospheric atmospheric conditions during autumn. This cycle occurred twice in relatively quick succession contributing to the record low values of the AO observed. Using a skillful winter temperature forecast, it is shown that the AO explained a greater variance of the observed temperature pattern across the extratropical landmasses of the NH than did ENSO. Further, and somewhat counter-intuitively, the severe cold winter weather may be attributed to boundary forcing changes consistent with an overall warming planet. A warmer atmosphere can hold more moisture and as the interior of the NH continents cool in fall, this can lead to increased snowfall. More extensive fall snow cover contributed to the extreme negative AO observed during the winter of 2009/10.

Cohen, J. L.; Foster, J. L.; Barlow, M. A.; Saito, K.; Jones, J.

2010-12-01

378

Simulating the formation and fate of dense water in a midlatitude marginal sea during normal and warm winter conditions  

NASA Astrophysics Data System (ADS)

Dense shelf water production and the deep convection process in the Adriatic Sea are investigated, considering two case studies: the first is representative of the present climatic situation, whereas the second may be expected in a scenario characterized by mild winter conditions over the basin. Dense water production and spreading are studied using a high-resolution implementation of the Massachusetts Institute of Technology general circulation model that is initialized and forced with realistic conditions. This paper provides qualitative and quantitative information on mass transport, dense water pathways, thermohaline structures, and the mixing properties of the basin. In the northern Adriatic shelf, seawater temperature is the key element for winter dense water production because it contributes more relevantly than salinity in determining density. In the southern Adriatic Sea, a small amount of dense water that cascades directly into the pit can be formed on the narrow western shelf only during cold winter conditions. Moreover, open ocean deepwater formation occurs in the middle of the southern basin. In late winter and spring, although only when winter conditions have been sufficiently cold, northern Adriatic dense shelf water forms a subsurface stream of which the densest part rapidly sinks in the southern pit along the shelf break, whereas its lighter part flows southward and reaches the Otranto Strait. The frequent occurrence of mild winter conditions could lead to lower dense water production, with a reduced dense water flow from the Adriatic Sea to the Ionian Sea and a potential great impact on the eastern Mediterranean thermohaline circulation.

Querin, Stefano; Cossarini, Gianpiero; Solidoro, Cosimo

2013-02-01

379

Cold Weather Aerostat Study.  

National Technical Information Service (NTIS)

Aerostats are being considered for application in cold weather regions. A review of aerostat flight experience to date was made to determine the limitations of the current technology. Areas for improvements and modifications to extend the aerostat system ...

R. L. Ashford

1982-01-01

380

Cold hardiness in molluscs  

NASA Astrophysics Data System (ADS)

Molluscs inhabit all types of environments: seawater, intertidal zone, freshwater and land, and of course may have to deal with subzero temperatures. Ectotherm animals survive cold conditions by avoiding it by extensive supercooling (freezing avoidant species) or by bearing the freezing of their extracellular body fluids (freezing tolerant species). Although some studies on cold hardiness are available for intertidal molluscs, they are scarce for freshwater and terrestrial ones. Molluscs often exhibit intermediary levels of cold hardiness, with a moderate or low ability to supercool and a limited survival to the freezing of their tissues. Several factors could be involved: their dependence on water, their ability to enter dormancy, the probability of inoculative freezing in their environment, etc. Size is an important parameter in the development of cold hardiness abilities: it influences supercooling ability in land snails, which are rather freezing avoidant and survival to ice formation in intertidal organisms, which generally tolerate freezing.

Ansart, Armelle; Vernon, Philippe

2003-05-01

381

Aerostat Cold Weather Study.  

National Technical Information Service (NTIS)

The arctic environment and its potential impact on Aerostat design and operations are discussed. Predictive meteorological resources available are summarized. Results of previous Aerostat operations in cold climates are reviewed and potential solutions di...

D. L. Kane

1989-01-01

382

Vitamin C and colds  

MedlinePLUS

Douglas RM, Hemilä H, Chalker E, Treacy B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev . 2007 Jul 18;(3):CD000980. Kilgore D. Common respiratory diseases. Prim ...

383

Cold and Cough Medicines  

MedlinePLUS

... or cough symptoms? Besides drinking plenty of fluids and getting plenty of rest, you may want to take medicines. There are lots of different cold and cough medicines, and they do different things. Nasal ...

384

Distribution patterns of American black duck and mallard winter band recoveries  

USGS Publications Warehouse

We compared the distribution patterns of winter band recoveries of American black ducks (Anas rubripes) and mallards (A. platyrhynchos) banded in the same breeding areas. Young black ducks wintered northeast of young mallards but no differences in distribution patterns were detected between adult birds of the 2 species. Mallards exhibited greater temporal variation in distribution patterns and less fidelity to wintering areas. We speculate that these differences in distribution patterns are related to different behavioral responses by mallards and black ducks to variation in resource availability. Black ducks may reduce energy expenditure during periods of extreme cold and wait for conditions to improve, whereas mallards may migrate to areas that are warmer of where more food is available. The availability of quality habitat may be critical to the survival of black ducks during harsh weather conditions because of their relative lack of migrational flexibility, whereas mallards may be able to respond by migrating to favorable environments.

Diefenbach, D.R.; Nichols, J.D.; Hines, J.E.

1988-01-01

385

Snow cover and extreme winter warming events control flower abundance of some, but not all species in high arctic Svalbard  

PubMed Central

Abstract The High Arctic winter is expected to be altered through ongoing and future climate change. Winter precipitation and snow depth are projected to increase and melt out dates change accordingly. Also, snow cover and depth will play an important role in protecting plant canopy from increasingly more frequent extreme winter warming events. Flower production of many Arctic plants is dependent on melt out timing, since season length determines resource availability for flower preformation. We erected snow fences to increase snow depth and shorten growing season, and counted flowers of six species over 5 years, during which we experienced two extreme winter warming events. Most species were resistant to snow cover increase, but two species reduced flower abundance due to shortened growing seasons. Cassiope tetragona responded strongly with fewer flowers in deep snow regimes during years without extreme events, while Stellaria crassipes responded partly. Snow pack thickness determined whether winter warming events had an effect on flower abundance of some species. Warming events clearly reduced flower abundance in shallow but not in deep snow regimes of Cassiope tetragona, but only marginally for Dryas octopetala. However, the affected species were resilient and individuals did not experience any long term effects. In the case of short or cold summers, a subset of species suffered reduced reproductive success, which may affect future plant composition through possible cascading competition effects. Extreme winter warming events were shown to expose the canopy to cold winter air. The following summer most of the overwintering flower buds could not produce flowers. Thus reproductive success is reduced if this occurs in subsequent years. We conclude that snow depth influences flower abundance by altering season length and by protecting or exposing flower buds to cold winter air, but most species studied are resistant to changes. Winter warming events, often occurring together with rain, can substantially remove snow cover and thereby expose plants to cold winter air. Depending on morphology, different parts of the plant can be directly exposed. On this picture, we see Dryas octopetala seed heads from the previous growing season protrude through the remaining ice layer after a warming event in early 2010. The rest of the plant, including meristems and flower primordia, are still somewhat protected by the ice. In the background we can see a patch of Cassiope tetragona protruding through the ice; in this case, the whole plant including flower primordia is exposed, which might be one reason why this species experienced a loss of flowers the following season. Photograph by Philipp Semenchuk.

Semenchuk, Philipp R; Elberling, Bo; Cooper, Elisabeth J

2013-01-01

386

Climate Change Affects Winter Chill for Temperate Fruit and Nut Trees  

PubMed Central

Background Temperate fruit and nut trees require adequate winter chill to produce economically viable yields. Global warming has the potential to reduce available winter chill and greatly impact crop yields. Methodology/Principal Findings We estimated winter chill for two past (1975 and 2000) and 18 future scenarios (mid and end 21st century; 3 Global Climate Models [GCMs]; 3 greenhouse gas emissions [GHG] scenarios). For 4,293 weather stations around the world and GCM projections, Safe Winter Chill (SWC), the amount of winter chill that is exceeded in 90% of all years, was estimated for all scenarios using the “Dynamic Model” and interpolated globally. We found that SWC ranged between 0 and about 170 Chill Portions (CP) for all climate scenarios, but that the global distribution varied across scenarios. Warm regions are likely to experience severe reductions in available winter chill, potentially threatening production there. In contrast, SWC in most temperate growing regions is likely to remain relatively unchanged, and cold regions may even see an increase in SWC. Climate change impacts on SWC differed quantitatively among GCMs and GHG scenarios, with the highest GHG leading to losses up to 40 CP in warm regions, compared to 20 CP for the lowest GHG. Conclusions/Significance The extent of projected changes in winter chill in many major growing regions of fruits and nuts indicates that growers of these commodities will likely experience problems in the future. Mitigation of climate change through reductions in greenhouse gas emissions can help reduce the impacts, however, adaption to changes will have to occur. To better prepare for likely impacts of climate change, efforts should be undertaken to breed tree cultivars for lower chilling requirements, to develop tools to cope with insufficient winter chill, and to better understand the temperature responses of tree crops.

Luedeling, Eike; Girvetz, Evan H.; Semenov, Mikhail A.; Brown, Patrick H.

2011-01-01

387

Deep Thermal Front (southeastern Brazilian coast) see through acoustics: a preliminary study from an operational oceanography perspective  

NASA Astrophysics Data System (ADS)

The continental shelf region off the southeastern Brazilian coast (between 20°S and 28°S) is characterized by intrusions of the relatively cold and fertile South Atlantic Central Water (SACW) from the open ocean. Prediction and monitoring of this water mass are topics of great interest given its importance, for example, on climate, carbon cycle, fishing, mariculture, nutrients and pollutants dispersion, and for the oil industry. The intersection of the 18°C isotherm with the seafloor is appointed in the literature as a good tracer for SACW presence on the continental shelf and also to characterize the Deep Thermal Front (DTF) [Castro, 1996]. Among different factors that drive the SACW penetration on the continental shelf, one prominent mechanism is the water transport driven by the conditions of NE-E wind forcing. These winds varies seasonally, and they are prevalent during the spring and summer months. During these months, the water column is generally stratified due the combined effects of solar heating and DTF presence. In contrast, the reverse effect is characteristic in winter, when the water column is nearly homogeneous, relatively colder on the surface and relatively warm close to the bottom. Consequently, the sound speed field changes and thus the acoustic rays are propagated with different characteristics depending on presence, absence or DTF position. Considering this information, acoustics may provide an additional source of data that supplements the other conventional methods (e.g., hydrographic moorings and cruises, buoys, gliders, and others) for tracking and monitoring the front movement. In addition, it is worth emphasizing that acoustic methods present one interesting advantage in that they are able to sample the water column over large three-dimensional distances on an effectively synoptic scale. In this paper, a preliminary study of acoustic propagation modelling through one vertical section off the Brazilian southeastern coast at Cananéia region (state of São Paulo) is presented. Theorical temperature and salinity fields with differents conditions of DTF position are used for the calculations. Notable variations in the transmission loss field, rays propagations and time arrivals are found when the DTF is moving. These results support the idea that acoustics can be an interesting tool in monitoring and tracking of DTF movement, especially in the context of an intregrated program of observational oceanography and numerical ocean modeling.

Ponsoni, L.; Hermand, J.-P.; da Silveira, I. C. A.

2012-04-01

388

Cyanobacteria in Cold Ecosystems  

Microsoft Academic Search

Perennially cold environments in which temperatures remain below 5°C are common throughout the biosphere (Margesin and Häggblom\\u000a 2007). In these habitats, the persistent cold temperatures are often accompanied by freeze—thaw cycles, extreme fluctuations\\u000a in irradiance (including ultraviolet radiation), and large variations in nutrient supply and salinity. As a result of these\\u000a constraints, polar and alpine environments contain a reduced biodiversity,

Frédéric Zakhia; Anne-Dorothee Jungblut; Arnaud Taton; Warwick F. Vincent; Annick Wilmotte

389

Distribution and diurnal behavior of Steller's Eiders wintering on the Alaska Peninsula  

USGS Publications Warehouse

We studied the distribution and activities of adult Steller's Eiders (Polysticta stelleri) during winter and spring on a deep-water embayment and a shallow lagoon along the Alaska Peninsula from September 1980 to May 1981. During the remigial molt, eiders were observed on Izembek Lagoon but not on Cold Bay. Following the flightless period, Izembek Lagoon continued to support 63-100% of eiders encountered during surveys. As ice cover on Izembek Lagoon increased, the number of birds decreased on Izembek Lagoon but increased on Cold Bay, suggesting that some eiders disperse to nearshore, deep-water habitats in close proximity to Izembek Lagoon during severe weather. Diurnal activity budgets indicated that the amount of time resting or engaged in aggression and alert activities was similar among locations, seasons, tidal stages, and sexes. In contrast, time spent foraging differed among seasons and locations but did not differ among tidal stages or sexes. Although time spent foraging was similar during winter and spring on Izembek Lagoon, eiders on Cold Bay foraged more during winter compared to spring. Synchronous diving was the dominant foraging strategy.

Laubhan, M. K.; Metzner, K. A.

1999-01-01

390

Condensation Front Migration in a Protoplanetary Nebula  

NASA Technical Reports Server (NTRS)

Condensation front dynamics are investigated in the mid-solar nebula region. A quasi-steady model of the evolving nebula is combined with equilibrium vapor pressure curves to determine evolutionary condensation fronts for selected species. These fronts are found to migrate inwards from the far-nebula to final positions during a period of 10(exp 7) years. The physical process governing this movement is a combination of local viscous heating and luminescent heating from the central star. Two luminescent heating models are used and their effects on the ultimate radial position of the condensation front are discussed. At first the fronts move much faster than the nebular accretion velocity, but after a time the accreting gas and dust overtakes the slowing condensation front.

Davis, Sanford S.

2004-01-01

391

Winter 2009/10: Season of extremes by chance or forced.  

NASA Astrophysics Data System (ADS)

Winter 2009/10 made headlines for extreme cold and snow in all the major population centres of the industrialized countries of the Northern Hemisphere. Record cold and snow occurred simultaneously in the US, Europe and East Asia, a highly unusual occurrence. The major teleconnection patterns of the Northern Hemisphere, El Nino/Southern Oscillation (ENSO) and the Arctic Oscillation (AO) were of moderate to strong amplitude, making both potentially key players in the climate of the Northern Hemisphere during the winter 2009/10. I will compare the relative influence of both teleconnection patterns on the hemispheric temperature pattern. Much of the Northern Hemisphere temperature anomalies from last winter can be attributed as a "textbook" case of ideas and trends presented at last year's EGU. The dominant Northern Hemisphere winter circulation pattern can be shown to have originated with a two-way stratosphere-troposphere interaction forced by Eurasian land surface lower tropospheric atmospheric conditions during autumn. In educating and in gaining the public's trust about our knowledge of climate in general and projected climate change in particular it is important to be able to attribute extreme weather events to a predictable and physical cause rather than to simply chance.

Cohen, Judah

2010-05-01

392

Global transcriptome profiles of Camellia sinensis during cold acclimation  

PubMed Central

Background Tea is the most popular non-alcoholic health beverage in the world. The tea plant (Camellia sinensis (L.) O. Kuntze) needs to undergo a cold acclimation process to enhance its freezing tolerance in winter. Changes that occur at the molecular level in response to low temperatures are poorly understood in tea plants. To elucidate the molecular mechanisms of cold acclimation, we employed RNA-Seq and digital gene expression (DGE) technologies to the study of genome-wide expression profiles during cold acclimation in tea plants. Results Using the Illumina sequencing platform, we obtained approximately 57.35 million RNA-Seq reads. These reads were assembled into 216,831 transcripts, with an average length of 356 bp and an N50 of 529 bp. In total, 1,770 differentially expressed transcripts were identified, of which 1,168 were up-regulated and 602 down-regulated. These include a group of cold sensor or signal transduction genes, cold-responsive transcription factor genes, plasma membrane stabilization related genes, osmosensing-responsive genes, and detoxification enzyme genes. DGE and quantitative RT-PCR analysis further confirmed the results from RNA-Seq analysis. Pathway analysis indicated that the “carbohydrate metabolism pathway” and the “calcium signaling pathway” might play a vital role in tea plants’ responses to cold stress. Conclusions Our study presents a global survey of transcriptome profiles of tea plants in response to low, non-freezing temperatures and yields insights into the molecular mechanisms of tea plants during the cold acclimation process. It could also serve as a valuable resource for relevant research on cold-tolerance and help to explore the cold-related genes in improving the understanding of low-temperature tolerance and plant-environment interactions.

2013-01-01

393

Efficient N Management Using Winter Oilseed Rape  

Microsoft Academic Search

\\u000a During the last decades the acreage of winter oilseed rape has been increased considerably in Europe. Rapeseed can take up\\u000a a large amount of nitrogen before winter (?>?100 kg N???ha) and thus prevent nitrate leaching and pollution. Winter wheat\\u000a is often grown subsequently, using oilseed rape as a favorable preceding crop. However, under wheat large nitrogen losses\\u000a via leaching are frequently observed

Klaus Sieling; Henning Kage

394

The dimensional regularization in light front  

NASA Astrophysics Data System (ADS)

We use dimensional regularization (DR) to evaluate a one-loop four-point function to order g2 in a scalar ?4 model using the light-front coordinates and performing the light-front energy variable integration in the first place. The DR in the light-front is applied to the D - 2 transverse variables. We show the equivalence of the result thus obtained with the standard DR applied to D dimensions.

Soriano, L. A.; Suzuki, A. T.; Sales, J. H.

2013-03-01

395

Dynamics of water evaporation fronts  

NASA Astrophysics Data System (ADS)

The evolution and shapes of water evaporation fronts caused by long-wave instability of vertical flows with a phase transition in extended two-dimensional horizontal porous domains are analyzed numerically. The plane surface of the phase transition loses stability when the wave number becomes infinite or zero. In the latter case, the transition to instability is accompanied with reversible bifurcations in a subcritical neighborhood of the instability threshold and by the formation of secondary (not necessarily horizontal homogeneous) flows. An example of motion in a porous medium is considered concerning the instability of a water layer lying above a mixture of air and vapor filling a porous layer under isothermal conditions in the presence of capillary forces acting on the phase transition interface.

Il'ichev, A. T.; Shargatov, V. A.

2013-09-01

396

Winter warming from large volcanic eruptions  

SciTech Connect

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

Robock, A.; Mao, J.

1992-01-01

397

Winter warming from large volcanic eruptions  

NASA Technical Reports Server (NTRS)

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

Robock, Alan; Mao, Jianping

1992-01-01

398

Winter Weather Tips for Cardiac Patients  

MedlinePLUS

... workload on the heart. People outdoors in cold weather should avoid sudden exertion, like lifting a heavy ... with your doctor prior to exercising in cold weather. Be aware of the dangers of hypothermia. Heart ...

399

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

Designed to help teachers deal with students in a cold environment, this article explains cold physiology and fundamental laws of heat; describes 14 common cold injuries and their current treatment; and lists a number of useful teaching techniques for cold environments. (SB)

Ewert, Alan

1979-01-01

400

Satellite evidence of wintertime atmospheric boundary layer responses to multiple SST fronts in the Japan Sea  

NASA Astrophysics Data System (ADS)

We present satellite evidence of wintertime atmospheric boundary layer responses to multiple sea surface temperature (SST) fronts in the Japan Sea under cold-air outbreak during 22-28 December 2005. It is found that the lower atmosphere adheres to the stepwise SST variations, focusing on a wind trajectory from the Eurasian continent to the northern Japan, which goes through the meandering Polar Front and the Tsushima Warm Current. Wind speed anomaly and wind divergence are linearly related to the SST anomaly and downwind SST gradient, respectively. Vertically uniform layers of potential temperature are accomplished when reaching the Polar Front and Tsushima Warm Current. Variations of water vapor mixing ratio and the resulting surface turbulent heat fluxes show also stepwise increases. Little wind vertical shear on the Japanese coast suggests that well-mixed boundary layer is eventually formed.

Shimada, Teruhisa; Kawamura, Hiroshi

2008-12-01

401

COLD WEATHER PLUME STUDY  

EPA Science Inventory

While many studies of power plant plume transport and transformation have been performed during the summer, few studies of these processes during the winter have been carried out. Accordingly, the U.S. Environmental Protection Agency and the Electric Power Research Institute join...

402

A winter survey of domestic heating among elderly patients.  

PubMed Central

Elderly people have a greater need for domestic heating given the time they spend at home and the decline in the body thermoregulation that occurs with ageing. The use of domestic heating by 200 mentally competent newly admitted elderly in patients was evaluated by means of a questionnaire survey. Most patients (69%) were aware of the addition of value added tax (VAT) to their fuel bill and 31% said they had reduced the amount of heating they use because of this. A third of patients (29.5%) said they had difficulty keeping warm prior to this admission. The majority of patients said they could not manage to keep warm in the winter without financial hardship. In addition, 29% said they had reduced the amount spent on food in order to pay for fuel bills. This study suggests that cold may contribute to hospital admissions in elderly patients. This should have implications for government spending and taxation policy on domestic heating.

Morgan, R; Blair, A; King, D

1996-01-01

403

Seasonal variation in nutritional characteristics of the diet of greater white-fronted geese  

USGS Publications Warehouse

We studied diet and habitat use of greater white-fronted geese (Anser albifrons) from autumn through spring on their primary staging and wintering areas in the Pacific Flyway, 1979-1982. There have been few previous studies of resource use and forage quality of wintering greater white-fronted geese in North America, and as a consequence there has been little empirical support for management practices pertaining to habitat conservation of this broadly distributed species. Observations of >2,500 flocks of geese and collections of foraging birds revealed seasonal and geographic variation in resource use reflective of changes in habitat availability, selection, and fluctuating physiological demands. Autumn migrants from Alaska arrived first in the Klamath Basin of California and southern Oregon, where they fed on barley, oats, wheat, and potatoes. Geese migrated from the Klamath Basin into the Central Valley of California in late autumn where they exploited agricultural crops rich in soluble carbohydrates, with geese in the Sacramento Valley feeding almost exclusively on rice and birds on the Sacramento-San Joaquin Delta primarily utilizing corn. White-fronted geese began their northward migration in late winter, and by early spring most had returned to the Klamath Basin where 37% of flocks were found in fields of new growth cultivated and wild grasses. Cereal grains and potatoes ingested by geese were low in protein (7-14%) and high in soluble nutrients (17-47% neutral detergent fiber [NDF]), whereas grasses were low in available energy (47-49% NDF) but high in protein (26-42%). Greater white-fronted geese are generalist herbivores and can exploit a variety of carbohydrate-rich cultivated crops, likely making these geese less susceptible to winter food shortages than prior to the agriculturalization of the North American landscape. However, agricultural landscapes can be extremely dynamic and may be less predictable in the long-term than the historic environments to which geese are adapted. Thus far greater white-fronted geese have proved resilient to changes in land cover in the Pacific Flyway and by altering their migration regime have even been able to adapt to changes in the availability of suitable forage crops. © 2010 The Wildlife Society.

Ely, Craig R.; Raveling, Dennis G.

2011-01-01

404

Winter Olympics Physics and Biomechanics  

NSDL National Science Digital Library

Many Winter Olympic sports are greatly dependent on technique, engineering, and/or gravity. For example, during luge, while gravity is accelerating the sled up to 80 mph down the track, the slider must use good technique to steer the sled and minimize air resistance. To excel in these type of sports, it is helpful to have a full appreciation of physics and biomechanics. Physics is a broad field which includes mechanics, electricity, magnetism, optics, etc., and biomechanics is the study of the mechanics of living systems. In the module we will use the sports of luge and figure skating to teach you four basic mechanical concepts: linear kinematics, linear dynamics, projectile motion, and conservation of angular momentum. In addition, we have developed a glossary which defines and illustrates all the physics terminology you will need to complete this module.

405

How Does Hot and Cold Gas Interact in Galaxies?  

NASA Astrophysics Data System (ADS)

Sa galaxies have roughly equal amounts of hot and cold gas, yet little is known about the interaction between the two phases. It is possible that the gas is thermally coupled, with cold gas cooling hot gas where the two phases interface. This would lead to a softening of the X-ray spectrum in the area of overlap. Alternatively, the phases could be thermally isolated, so that the cold gas in front of the hot gas absorbs soft X-rays behind it. We propose to observe two galaxies with unusual HI distributions to search for the interaction between the two phases. We will verify whether the hot gas fills the holes in the HI distribution. We will also investigate the lack of very luminous LMXBs in spiral bulges, and determine the luminosity function of the LMXBs that do exist in the bulges.

Irwin, Jimmy

2003-09-01

406

The Interaction of Hot and Cold Gas in Galaxies  

NASA Astrophysics Data System (ADS)

Sa galaxies have roughly equal amounts of hot and cold gas, yet little is known about the interaction between the two phases. It is possible that the gas is thermally coupled, with cold gas cooling hot gas where the two phases interface. This would lead to a softening of the X-ray spectrum in the area of overlap. Alternatively, the phases could be thermally isolated, so that the cold gas in front of the hot gas absorbs soft X-rays behind it. We propose to observe three galaxies with unusual HI distributions to search for the interaction between the two phases. We will verify whether the hot gas fills the holes in the HI distribution. We will also investigate the lack of very luminous LMXBs in spiral bulges, and determine the luminosity function of the LMXBs that do exist in the bulges.

Irwin, Jimmy

2002-09-01

407

A New East Asian Winter Monsoon Index and Associated Characteristics of the Winter Monsoon  

Microsoft Academic Search

A new East Asian winter monsoon index, which reflects the 300-hPa meridional wind shear associated with the jet stream, was defined to describe the variability of the winter monsoon in midlatitude East Asia. This index represents very well the seasonal mean winter temperature over Korea, Japan, and eastern China. The National Centers for Environmental Prediction National Center for Atmospheric Research

Jong-Ghap Jhun; Eun-Jeong Lee

2004-01-01

408

Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness  

Microsoft Academic Search

The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of

Keiichiro Matsukura; Hisaaki Tsumuki; Yohei Izumi; Takashi Wada

2008-01-01

409

Accumulation of Small Heat-Shock Protein Homologs in the Endoplasmic Reticulum of Cortical Parenchyma Cells in Mulberry in Association with Seasonal Cold Acclimation  

Microsoft Academic Search

Cortical parenchyma cells of mulberry (Morus bombycis Koidz.) trees acquire extremely high freezing tolerance in winter as a result of seasonal cold acclimation. The amount of total proteins in endo- plasmic reticulum (ER)-enriched fractions isolated from these cells increased in parallel with the process of cold acclimation. Protein compositions in the ER-enriched fraction also changed seasonally, with a prominent accumulation

Norifumi Ukaji; Chikako Kuwabara; Daisuke Takezawa; Keita Arakawa; Shizuo Yoshida; Seizo Fujikawa

1999-01-01

410

Immunolocalization of Antifreeze Proteins in Winter Rye Leaves, Crowns, and Roots by Tissue Printing.  

PubMed Central

During cold acclimation, antifreeze proteins (AFPs) that are similar to pathogenesis-related proteins accumulate in the apoplast of winter rye (Secale cereale L. cv Musketeer) leaves. AFPs have the ability to modify the growth of ice. To elucidate the role of AFPs in the freezing process, they were assayed and immunolocalized in winter rye leaves, crowns, and roots. Each of the total soluble protein extracts from cold-acclimated rye leaves, crowns, and roots exhibited antifreeze activity, whereas no antifreeze activity was observed in extracts from nonacclimated rye plants. Antibodies raised against three apoplastic rye AFPs, corresponding to a glucanase-like protein (GLP, 32 kD), a chitinase-like protein (CLP, 35 kD), and a thaumatin-like protein (TLP, 25 kD), were used in tissue printing to show that the AFPs are localized in the epidermis and in cells surrounding intercellular spaces in cold-acclimated plants. Although GLPs, CLPs, and TLPs were present in nonacclimated plants, they were found in different locations and did not exhibit antifreeze activity, which suggests that different isoforms of pathogenesis-related proteins are produced at low temperature. The location of rye AFPs may prevent secondary nucleation of cells by epiphytic ice or by ice propagating through the xylem. The distributions of pathogenesis-induced and cold-accumulated GLPs, CLPs, and TLPs are similar and may reflect the common pathways by which both pathogens and ice enter and propagate through plant tissues.

Antikainen, M.; Griffith, M.; Zhang, J.; Hon, W. C.; Yang, DSC.; Pihakaski-Maunsbach, K.

1996-01-01

411

Fatality Assessment and Control Evaluation (FACE) Report for Michigan: Farm Laborer Died When Struck By Front End Loading Bucket, FACE-12-MI-008.  

National Technical Information Service (NTIS)

In winter 2012, a male farm hand in his 60s died when he was struck by a 2006 Komatso WA 250 front end loader with an 8-foot 10-inch wide, 4-cubic yard bucket. The incident occurred prior to sunrise. The weather was overcast with little moonlight. The dec...

2013-01-01

412

A spatial model of urban winter woodsmoke concentrations.  

PubMed

In many urban areas, residential wood burning is a significant wintertime source of PM2.5. In this study, we used a combination of fixed and mobile monitoring along with a novel spatial buffering procedure to estimate the spatial patterns of woodsmoke. Two-week average PM2.5 and levoglucosan (a marker for wood smoke) concentrations were concurrently measured at upto seven sites in the study region. In addition, pre-selected routes spanning the major population areas in and around Vancouver, B.C. were traversed during 19 cold, clear winter evenings from November, 2004 to March, 2005 by a vehicle equipped with GPS receiver and a nephelometer. Fifteen-second-average values of light scattering coefficient (bsp) were adjusted for variations between evenings and then combined into a single, highly resolved map of nighttime winter bsp levels. A relatively simple but robust (R(2) = 0.64) land use regression model was developed using selected spatial covariates to predict these temporally adjusted bsp values. The bsp values predicted by this model were also correlated with the measured average levoglucosan concentrations at our fixed site locations (R(2) = 0.66). This model, the first application of land use regression for woodsmoke, enabled the identification and prediction of previously unrecognized high woodsmoke regions within an urban airshed. PMID:17438796

Larson, Timothy; Su, Jason; Baribeau, Anne-Marie; Buzzelli, Michael; Setton, Eleanor; Brauer, Michael

2007-04-01

413

Theoretical models of adaptive energy management in small wintering birds.  

PubMed

Many small passerines are resident in forests with very cold winters. Considering their size and the adverse conditions, this is a remarkable feat that requires optimal energy management in several respects, for example regulation of body fat reserves, food hoarding and night-time hypothermia. Besides their beneficial effect on survival, these behaviours also entail various costs. The scenario is complex with many potentially important factors, and this has made 'the little bird in winter' a popular topic for theoretic modellers. Many predictions could have been made intuitively, but models have been especially important when many factors interact. Predictions that hardly could have been made without models include: (i) the minimum mortality occurs at the fat level where the marginal values of starvation risk and predation risk are equal; (ii) starvation risk may also decrease when food requirement increases; (iii) mortality from starvation may correlate positively with fat reserves; (iv) the existence of food stores can increase fitness substantially even if the food is not eaten; (v) environmental changes may induce increases or decreases in the level of reserves depending on whether changes are temporary or permanent; and (vi) hoarding can also evolve under seemingly group-selectionistic conditions. PMID:17827099

Brodin, Anders

2007-10-29

414

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999-2000 winter season. Aircraft based water vapor, carbon monoxide, and ozone measurements are analyzed so as to establish how deeply tropospheric air mixes into the arctic lower-most stratosphere, and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to- stratosphere exchange extends into the arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases idly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of about 5 ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20\\% of the parcels which have ozone values of 300-350ppbv experiencing ice saturation in a given 10 day period. Third, during early Spring temperatures at the tropopause are cold enough so that 5-10\\% of parcels experience relative humidities above 100\\%, even if the water content is as low as 5 ppmv. The implication is that during, this period the arctic tropopause can play an important role in maintaining a very dry upper troposphere during early Spring.

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Hipskino, R. Stephen (Technical Monitor)

2001-01-01

415

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

2002-01-01

416

Terra Data Confirm Warm, Dry U.S. Winter  

NASA Technical Reports Server (NTRS)

New maps of land surface temperature and snow cover produced by NASA's Terra satellite show this year's winter was warmer than last year's, and the snow line stayed farther north than normal. The observations confirm earlier National Oceanic and Atmospheric Administration reports that the United States was unusually warm and dry this past winter. (Click to read the NASA press release and to access higher-resolution images.) For the last two years, a new sensor aboard Terra has been collecting the most detailed global measurements ever made of our world's land surface temperatures and snow cover. The Moderate-resolution Imaging Spectroradiometer (MODIS) is already giving scientists new insights into our changing planet. Average temperatures during December 2001 through February 2002 for the contiguous United States appear to have been unseasonably warm from the Rockies eastward. In the top image the coldest temperatures appear black, while dark green, blue, red, yellow, and white indicate progressively warmer temperatures. MODIS observes both land surface temperature and emissivity, which indicates how efficiently a surface absorbs and emits thermal radiation. Compared to the winter of 2000-01, temperatures throughout much of the U.S. were warmer in 2001-02. The bottom image depicts the differences on a scale from dark blue (colder this year than last) to red (warmer this year than last). A large region of warm temperatures dominated the northern Great Plains, while the area around the Great Salt Lake was a cold spot. Images courtesy Robert Simmon, NASA GSFC, based upon data courtesy Zhengming Wan, MODIS Land Science Team member at the University of California, Santa Barbara's Institute for Computational Earth System Science

2002-01-01

417

Solar wind influence on atmospheric processes in winter Antarctica  

NASA Astrophysics Data System (ADS)

The experimental results demonstrate influence of the great southward interplanetary magnetic field (IMF) and the corresponding geoeffective interplanetary electric field on atmospheric pro-cesses in the central Antarctica, where the large-scale system of vertical circulation takes place during the winter seasons. The interplanetary electric field influence is realized through ac-celeration of the air masses, descending into the lower atmosphere from the troposphere, and formation of cloudiness above the Antarctic Ridge, where the descending air masses enter the surface layer. The cloudiness results in the sudden warmings in the surface atmosphere, because the cloud layer efficiently backscatters the long wavelength radiation going from ice sheet, but does not affect the process of adiabatic warming of the descending air masses. Influence of the interplanetary electric field on cloudiness has been revealed for epochs of the solar activity minimum, when Forbush decreases effect is absent. The altitudinal profiles of temperature, varying in the opposite manner under influence of the southward and northward IMF, indicate that the cloud layer formation occurs at h = 8 -10 km. The acceleration of the descending air masses is followed by a sharp increase of the atmospheric pressure in the near-pole region, which gives rise to the katabatic wind strengthening above the entire Antarctica. As a result, the circumpolar vortex around the periphery of the Antarctic continent decays and the surface easterlies, typical of the coast stations during the winter season, are replaced by southerlies. It is suggested that the resulting invasion of the cold air masses into the Southern ocean leads to destruction the regular relationships between the sea level pressure fluctuations in the South-east Pacific high and the North Australian-Indonesian low, since development the El-Niño event n strongly follows anomalous atmospheric processes in the winter Antarctica.

Troshichev, Oleg; Egorova, Larisa; Vovk, Valery; Janzhura, Alexander

418

Multiple deprivation and excess winter deaths in Scotland.  

PubMed

The recent publication of the Scottish Index of Multiple Deprivation (SIMD) has allowed some tentative statistical correlations to be undertaken to assess the impact poverty may have on mortality and morbidity. During the period 1989 to 2001, Scotland registered around 51,600 excess winter deaths (EWDs). An EWD is taken as the additional deaths during December to March than occurred in the preceding and subsequent four-month periods. Almost all of these EWDs were in the population aged over 65. This represents 50 more deaths per day in January than in July. The SIMD measured five criteria by region: income; employment; health and disability; education, skills and training; and geographical access to services. Glasgow was the most deprived region with an SIMD score of 46.88 and East Dunbartonshire, the least deprived region, with a score of 9.07. For the over 65s, the chance of becoming an EWD in Glasgow is one in 36, rising to one in 68 for North Ayrshire. The SIMD is positively correlated with EWD by region (0.35 at the 5% confidence level). This correlation appears to go against the influence of climatic variations, house type, energy efficiency and access to the gas network which favours urban areas. Although some of the additional winter deaths have been ascribed to outdoor cold exposure--exacerbated by inappropriate clothing or culturally determined behaviour--the majority of EWDs are premature and essentially preventable if the elderly can be kept warm in their homes during the winter months. PMID:15712848

Howieson, Stirling G; Hogan, M

2005-01-01

419

PLCO News, Fall/Winter 1998  

Cancer.gov

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 Cancer Information Center If you have a question about cancer you can call and speak with a trained specialist at NCI's Cancer Information Service (CIS). The CIS operates a toll-free,

420

PLCO News, Fall/Winter 1998  

Cancer.gov

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 Trial Update Enrollment goal: 148,000 Total enrollment (as of September 30, 1998): 111,515 Men enrolled: 58,283 Women enrolled: 53,232 Number of people enrolled

421

Effects of fluctuations on propagating fronts  

NASA Astrophysics Data System (ADS)

Propagating fronts are seen in varieties of nonequilibrium pattern forming systems in Physics, Chemistry and Biology. In the last two decades, many researchers have contributed to the understanding of the underlying dynamics of the propagating fronts. Of these, the deterministic and mean-field dynamics of the fronts were mostly understood in late 1980s and 1990s. On the other hand, although the earliest work on the effect of fluctuations on propagating fronts dates back to early 1980s, the subject of fluctuating fronts did not reach its adolescence until the mid 1990s. From there onwards the last few years witnessed a surge in activities in the effect of fluctuations on propagating fronts. Scores of papers have been written on this subject since then, contributing to a significant maturity of our understanding, and only recently a full picture of fluctuating fronts has started to emerge. This review is an attempt to collect all the works on fluctuating (propagating) fronts in a coherent and cogent manner in proper perspective. It is based on the idea of making our knowledge in this field available to a broader audience, and it is also expected to help to collect bits and pieces of loose thread-ends together for possible further investigation.

Panja, Debabrata

422

Structure and Stability of Ionization Fronts  

NASA Astrophysics Data System (ADS)

The study of the dynamics of ionization fronts has moved far since Franz Kahn helped define the field in the 1950s. Nevertheless, the stability of the fronts and the nature of elephant trunks and bright rims in HII regions remain contentious issues.

Williams, R. J. R.; Dyson, J. E.; Pavlakis, K.

423

1990 Front Range Meeting and Abstracts  

Microsoft Academic Search

The theme of the 1990 Front Range Branch meeting was Our Changing Environment. This broad topic was intended to encompass a variety of geophysical disciplines over geologic time, but special emphasis was placed on research relating to the Rocky Mountains, the Front Range, and High Plains. In a departure from earlier years, the meeting was held in Boulder, Colo., at

Jo Ann Joselyn; Ray Roble

1990-01-01

424

The structure and dynamics of an observed moist front  

NASA Technical Reports Server (NTRS)

The structure and dynamics of the moist cold front of 25 and 26 April 1979, the third observing day of the Severe Environmental Storms and Mesoscale experiment (SESAME), are investigated through the use of a three-dimensional mesoscale numerical model. This work is one of the first studies in which model results are compared, in a one-to-one manner, with a detailed observational analysis, namely that of Ogura and Portis (1982) as taken from the SESAME observations. In addition, frontogenetical effects, both adiabatic and diabatic, are studied on a vertical cross-section through the front; similarities and differences with the adiabatic analysis of Ogura and Portis are discussed. Many similarities exist between the modeled and analyzed fields, although the analysis tends to have weaker horizontal gradients due to the coarseness of the observational network. Vorticity and convergence near the surface were found to have the same magnitude in both the model solution and the analysis, in contrast to idealized frontogenesis models which predict vorticity to be much larger than convergence.

Orlanski, I.

1985-01-01

425

Akt activation protects liver cells from apoptosis in rats during acute cold exposure.  

PubMed

Accidental deaths due to exposure to extremely low natural temperature happen every winter. Exposure to extreme cold causes injury of multiple organs. However, early responses of the bodies to acute extreme cold exposure remain incompletely understood. In this study, we found that hepatic glycogen was rapidly reduced in rats exposed to -15°C, and the key enzymes required for glycogenesis were upregulated in the livers of the cold-exposed rats. In line with the rapid consumption of glycogen, acute cold exposure induced a transient elevation of cellular ATP level, which lasted about one hour. The ATP level went back to basal level after two hours of cold exposure. Four hours of cold exposure resulted in cellular ATP depletion and cell apoptosis. The dynamic change of cellular ATP levels was well associated with Akt activation in cold-exposed liver cells. The activation of Akt was required for cold exposure-induced ATP elevation. Blockade of Akt activation diminished the transient increase of intracellular ATP content and exacerbated cell apoptosis during acute cold exposure. These results suggest that Akt activation plays a pivotal role in maintaining cellular bioenergy balance and promoting liver cell survival during acute cold exposure. PMID:23781144

Wang, Jiye; Chen, Yaoming; Zhang, Wenbin; Zheng, Gang; Meng, Shanshan; Che, Honglei; Ke, Tao; Yang, Jingrun; Chen, Jingyuan; Luo, Wenjing

2013-01-01

426

Mechanisms of age-dependent response to winter temperature in perennial flowering of Arabis alpina.  

PubMed

Perennial plants live for more than 1 year and flower only after an extended vegetative phase. We used Arabis alpina, a perennial relative of annual Arabidopsis thaliana, to study how increasing age and exposure to winter cold (vernalization) coordinate to establish competence to flower. We show that the APETALA2 transcription factor, a target of microRNA miR172, prevents flowering before vernalization. Additionally, miR156 levels decline as A. alpina ages, causing increased production of SPL (SQUAMOSA PROMOTER BINDING PROTEIN LIKE) transcription factors and ensuring that flowering occurs in response to cold. The age at which plants respond to vernalization can be altered by manipulating miR156 levels. Although miR156 and miR172 levels are uncoupled in A. alpina, miR156 abundance represents the timer controlling age-dependent flowering responses to cold. PMID:23723236

Bergonzi, Sara; Albani, Maria C; Ver Loren van Themaat, Emiel; Nordström, Karl J V; Wang, Renhou; Schneeberger, Korbinian; Moerland, Perry D; Coupland, George

2013-05-31

427

Relativistic ionization fronts in gas jets  

NASA Astrophysics Data System (ADS)

A high-power ultra-short laser pulse propagating through a gas jet, ionizes the gas by tunnelling ionization, creating a relativistic plasma-gas interface. The relativistic ionization front that is created can be used to frequency up-shift electromagnetic radiation either in co-propagation or in counter-propagation configurations. In the counter-propagation configuration, ionization fronts can act as relativistic mirrors for terahertz radiation, leading to relativistic double Doppler frequency up-shift to the visible range. In this work, we identified and explored, the parameters that optimize the key features of relativistic ionization fronts for terahertz radiation reflection. The relativistic ionization front generated by a high power laser (TOPS) propagating in a supersonic gas jet generated by a Laval nozzle has been fully characterized. We have also performed detailed two-dimensional relativistic particle-in-cell simulations with Osiris 2.0 to analyze the generation and propagation of the ionization fronts.

Lemos, Nuno; Dias, J. M.; Gallacher, J. G.; Issac, R. C.; Fonseca, R. A.; Lopes, N. C.; Silva, L. O.; Mendonça, J. T.; Jaroszynski, D. A.

2006-10-01

428

Acral coldness in migraineurs.  

PubMed

In search for new biomarkers of vascular disturbances accompanying migraine, we compared the facial and hand skin temperatures in 41 women, including 12 migraine patients during the headache-free period and 29 healthy controls. Compared to the controls, the acral skin temperatures were lower in migraineurs, especially in those with right-sided headache. Our findings suggest that migraine is associated with a peripheral coldness possibly due to abnormal autonomic vascular control. The cold nose and hands may represent easily assessable biomarkers of these disorders. PMID:24080404

Zaproudina, Nina; Lipponen, Jukka A; Karjalainen, Pasi A; Kamshilin, Alexei A; Giniatullin, Rashid; Närhi, Matti

2014-02-01

429

Cold Dark Matter  

NASA Astrophysics Data System (ADS)

Motivated by inflation, the theory of big-bang nucleosynthesis, and the quest for a deeper understanding of fundamental forces and particles, a paradigm for the development of structure in the universe has evolved. It holds that most of the matter exists in the form of slowly moving elementary particles left over from the earliest moments--cold dark matter-and that the small density inhomogeneities that seed structure formation arose from quantum fluctuations around 10-34 seconds after the big bang. A flood of observations, from determinations of the Hubble constant to measurements of the anisotropy of cosmic background radiation, are now testing the cold dark matter paradigm.

Dodelson, Scott; Gates, Evalyn I.; Turner, Michael S.

1996-10-01

430

Role of CBFs as Integrators of Chloroplast Redox, Phytochrome and Plant Hormone Signaling during Cold Acclimation  

PubMed Central

Cold acclimation of winter cereals and other winter hardy species is a prerequisite to increase subsequent freezing tolerance. Low temperatures upregulate the expression of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) which in turn induce the expression of COLD-REGULATED (COR) genes. We summarize evidence which indicates that the integration of these interactions is responsible for the dwarf phenotype and enhanced photosynthetic performance associated with cold-acclimated and CBF-overexpressing plants. Plants overexpressing CBFs but grown at warm temperatures mimic the cold-tolerant, dwarf, compact phenotype; increased photosynthetic performance; and biomass accumulation typically associated with cold-acclimated plants. In this review, we propose a model whereby the cold acclimation signal is perceived by plants through an integration of low temperature and changes in light intensity, as well as changes in light quality. Such integration leads to the activation of the CBF-regulon and subsequent upregulation of COR gene and GA 2-oxidase (GA2ox) expression which results in a dwarf phenotype coupled with increased freezing tolerance and enhanced photosynthetic performance. We conclude that, due to their photoautotrophic nature, plants do not rely on a single low temperature sensor, but integrate changes in light intensity, light quality, and membrane viscosity in order to establish the cold-acclimated state. CBFs appear to act as master regulators of these interconnecting sensing/signaling pathways.

Kurepin, Leonid V.; Dahal, Keshav P.; Savitch, Leonid V.; Singh, Jas; Bode, Rainer; Ivanov, Alexander G.; Hurry, Vaughan; Huner, Norman P. A.

2013-01-01

431

Front end for GPS receivers  

NASA Technical Reports Server (NTRS)

The front end in GPS receivers has the functions of amplifying, down-converting, filtering and sampling the received signals. In the preferred embodiment, only two operations, A/D conversion and a sum, bring the signal from RF to filtered quadrature baseband samples. After amplification and filtering at RF, the L1 and L2 signals are each sampled at RF at a high selected subharmonic rate. The subharmonic sample rates are approximately 900 MHz for L1 and 982 MHz for L2. With the selected subharmonic sampling, the A/D conversion effectively down-converts the signal from RF to quadrature components at baseband. The resulting sample streams for L1 and L2 are each reduced to a lower rate with a digital filter, which becomes a straight sum in the simplest embodiment. The frequency subsystem can be very simple, only requiring the generation of a single reference frequency (e.g. 20.46 MHz minus a small offset) and the simple multiplication of this reference up to the subharmonic sample rates for L1 and L2. The small offset in the reference frequency serves the dual purpose of providing an advantageous offset in the down-converted carrier frequency and in the final baseband sample rate.

Thomas, Jr., Jess Brooks (Inventor)

1999-01-01