Temporal genetic structure and relatedness in the Tufted Duck Aythya fuligula suggests limited kin association in winter

Conspecific aggregation of waterfowl in winter is a common example of animal flocking behaviour, yet patterns of relatedness and temporal substructure in such social groups remain poorly understood even in common species. A previous study based on mark-recapture data showed that Tufted Ducks Aythya fuligula caught on the same day were re-caught together in subsequent winters more often than expected by chance, suggesting stable assortments of ‘socially familiar’ individuals between wintering periods. The genetic relationships within these social groups were not clear. Based on 191 individuals genotyped at 10 microsatellite markers, we investigated the temporal genetic structure and patterns of relatedness among wintering Tufted Ducks at Lake Sempach, Switzerland, in two consecutive winters. We found no evidence of genetic differentiation between temporal groups within or between winters. The average levels of relatedness in temporal groups were low and not higher than expected in random assortments of individuals. However, Mantel tests performed for each sex separately revealed significant negative correlations between the pairwise relatedness coefficients and the number of days between the capture dates of pairs of wintering Tufted Duck in males and females. This pattern suggests the presence of a small number of co-migrating same-sex sibling pairs in wintering flocks of Tufted Ducks. Our findings provide one of the first genetic analyses of a common duck species outside the breeding season and contribute to the understanding of social interactions in long-distance migratory birds.

Northern hemispheric winter warming pattern after tropical volcanic eruptions: Sensitivity to the ozone climatology

An important key for the understanding of the dynamic response to large tropical volcanic eruptions is the warming of the tropical lower stratosphere and the concomitant intensification of the polar vortices. Although this mechanism is reproduced by most general circulation models today, most models still fail in producing an appropriate winter warming pattern in the Northern Hemisphere. In this study ensemble sensitivity experiments were carried out with a coupled atmosphere-ocean model to assess the influence of different ozone climatologies on the atmospheric dynamics and in particular on the northern hemispheric winter warming. The ensemble experiments were perturbed by a single Tambora-like eruption. Larger meridional gradients in the lower stratospheric ozone favor the coupling of zonal wind anomalies between the stratosphere and the troposphere after the eruption. The associated sea level pressure, temperature, and precipitation patterns are more pronounced and the northern hemispheric winter warming is highly significant. Conversely, weaker meridional ozone gradients lead to a weaker response of the winter warming and the associated patterns. The differences in the number of stratosphere-troposphere coupling events between the ensembles experiments indicate a nonlinear response behavior of the dynamics with respect to the ozone and the volcanic forcing.

Are Greenhouse Gas Signals of Northern Hemisphere winter extra-tropical cyclone activity dependent on the identification and tracking algorithm?

For Northern Hemisphere extra-tropical cyclone activity, the dependency of a potential anthropogenic climate change signal on the identification method applied is analysed. This study investigates the impact of the used algorithm on the changing signal, not the robustness of the climate change signal itself. Using one single transient AOGCM simulation as standard input for eleven state-of-the-art identification methods, the patterns of model simulated present day climatologies are found to be close to those computed from re-analysis, independent of the method applied. Although differences in the total number of cyclones identified exist, the climate change signals (IPCC SRES A1B) in the model run considered are largely similar between methods for all cyclones. Taking into account all tracks, decreasing numbers are found in the Mediterranean, the Arctic in the Barents and Greenland Seas, the mid-latitude Pacific and North America. Changing patterns are even more similar, if only the most severe systems are considered: the methods reveal a coherent statistically significant increase in frequency over the eastern North Atlantic and North Pacific. We found that the differences between the methods considered are largely due to the different role of weaker systems in the specific methods.

Within-winter movements: a common phenomenon in the Common Pochard Aythya ferina

Waterbirds are often observed to move between different wintering sites within the same winter—for example, in response to food availability or weather conditions. Within-winter movements may contribute to the spreading of diseases, such as avian influenza, outside the actual migration period. The Common Pochard Aythya ferina seems to be particularly sensitive to infection with the highly pathogenic avian influenza virus H5N1 and, consequently, could play an important role as vectors for the disease. We describe here the within-winter movements of Pochards in Europe in relation to topography, climate, sex and age. We analysed data provided by the Euring data bank on 201 individuals for which records from different locations from the same winter (December–February) were available. The distances and directions moved within the winter varied markedly between regions, which could be ascribed to the differing topography (coast lines, Alps). We found no significant differences in terms of distances and directions moved between the sexes and only weak indications of differences between the age classes. In Switzerland, juveniles moved in more westerly directions than adults. During relatively mild winters, winter harshness had no effect on the distances travelled, but in cold winters, a positive relationship was observed, a pattern possibly triggered by the freezing of lakes. Winter harshness did not influence the directions of the movement. About 41% (83/201) of the Pochards that were recovered at least 1 km from the ringing site had moved more than 200 km. A substantial number of birds moved between central/southern Europe and the north-western coast of mainland Europe, and between the north-western coast of mainland Europe and Great Britain, whereas no direct exchange between Great Britain and central/southern Europe was observed. Within-winter movements of Pochards seem to be a common phenomenon in all years and possibly occur as a response to the depletion of food resources. This high tendency to move could potentially contribute to the spread of bird-transmitted diseases outside the actual migration period.

Family Preservation Journal, Winter 1996, Volume 1. (Entire issue)

Entire issue (large pdf file) Articles include: Improving Family Functioning through Family Preservation Services: Results of the Los Angeles Experiment. Family Preservation Journal. William Meezan and Jacquelyn McCroskey Idiographic Self-Monitoring Instruments to Empower Client Participation and Evaluate Outcome in Intensive Family Preservation Services. Barbara Peo Early Evaluating Family Preservation in Nevada: A University-State Agency Collaboration. Christine Bitoni and Joy Salmon The Family Partners Credit Card: A Token Economy System Adapted for Intensive Family Preservation Services to Enable Families to Manage Difficult Behavior of Adolescents. Jude Nichols and Barbara Peo Early Toward the Development of Ethical Guidelines for Family Preservation. David A Dosser Jr., Richard J. Shaffer, Michaux M. Shaffer, DeVault Clevenger, and Dustin K. Jefferies

Polar MM5 Simulations of the Winter Climate of the Laurentide Ice Sheet at the LGM

Optimized regional climate simulations are conducted using the Polar MM5, a version of the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5), with a 60-km horizontal resolution domain over North America during the Last Glacial Maximum (LGM, 21 000 calendar years ago), when much of the continent was covered by the Laurentide Ice Sheet (LIS). The objective is to describe the LGM annual cycle at high spatial resolution with an emphasis on the winter atmospheric circulation. Output from a tailored NCAR Community Climate Model version 3 (CCM3) simulation of the LGM climate is used to provide the initial and lateral boundary conditions for Polar MM5. LGM boundary conditions include continental ice sheets, appropriate orbital forcing, reduced CO2 concentration, paleovegetation, modified sea surface temperatures, and lowered sea level. Polar MM5 produces a substantially different atmospheric response to the LGM boundary conditions than CCM3 and other recent GCM simulations. In particular, from November to April the upper-level flow is split around a blocking anticyclone over the LIS, with a northern branch over the Canadian Arctic and a southern branch impacting southern North America. The split flow pattern is most pronounced in January and transitions into a single, consolidated jet stream that migrates northward over the LIS during summer. Sensitivity experiments indicate that the winter split flow in Polar MM5 is primarily due to mechanical forcing by LIS, although model physics and resolution also contribute to the simulated flow configuration. Polar MM5 LGM results are generally consistent with proxy climate estimates in the western United States, Alaska, and the Canadian Arctic and may help resolve some long-standing discrepancies between proxy data and previous simulations of the LGM climate.

Air-Sea Interactions During the Passage of a Winter Storm Over the Gulf Stream: A Three-Dimensional Coupled Atmosphere-Ocean Model Study

A three-dimensional, regional coupled atmosphere-ocean model with full physics is developed to study air-sea interactions during winter storms off the U. S. east coast. Because of the scarcity of open ocean observations, models such as this offer valuable opportunities to investigate how oceanic forcing drives atmospheric circulation and vice versa. The study presented here considers conditions of strong atmospheric forcing (high wind speeds) and strong oceanic forcing (significant sea surface temperature (SST) gradients). A simulated atmospheric cyclone evolves in a manner consistent with Eta reanalysis, and the simulated air-sea heat and momentum exchanges strongly affect the circulations in both the atmosphere and the ocean. For the simulated cyclone of 19-20 January 1998, maximum ocean-to-atmosphere heat fluxes first appear over the Gulf Stream in the South Atlantic Bight, and this results in rapid deepening of the cyclone off the Carolina coast. As the cyclone moves eastward, the heat flux maximum shifts into the region near Cape Hatteras and later northeast of Hatteras, where it enhances the wind locally. The oceanic response to the atmospheric forcing is closely related to the wind direction. Southerly and southwesterly winds tend to strengthen surface currents in the Gulf Stream, whereas northeasterly winds weaken the surface currents in the Gulf Stream and generate southwestward flows on the shelf. The oceanic feedback to the atmosphere moderates the cyclone strength. Compared with a simulation in which the oceanic model always passes the initial SST to the atmospheric model, the coupled simulation in which the oceanic model passes the evolving SST to the atmospheric model produces higher ocean-to-atmosphere heat flux near Gulf Stream meander troughs. This is due to wind-driven lateral shifts of the stream, which in turn enhance the local northeasterly winds. Away from the Gulf Stream the coupled simulation produces surface winds that are 5 similar to 10% weaker. Differences in the surface ocean currents between these two experiments are significant on the shelf and in the open ocean.

Multi-proxy summer and winter precipitation reconstruction for southern Africa over the last 200 years

This study presents the first consolidation of palaeoclimate proxy records from multiple archives to develop statistical rainfall reconstructions for southern Africa covering the last two centuries. State-of-the-art ensemble reconstructions reveal multi-decadal rainfall variability in the summer and winter rainfall zones. A decrease in precipitation amount over time is identified in the summer rainfall zone. No significant change in precipitation amount occurred in the winter rainfall zone, but rainfall variability has increased over time. Generally synchronous rainfall fluctuations between the two zones are identified on decadal scales, with common wet (dry) periods reconstructed around 1890 (1930). A strong relationship between seasonal rainfall and sea surface temperatures (SSTs) in the surrounding oceans is confirmed. Coherence among decadal-scale fluctuations of southern African rainfall, regional SST, SSTs in the Pacific Ocean and rainfall in south-eastern Australia suggest SST-rainfall teleconnections across the southern hemisphere. Temporal breakdowns of the SST-rainfall relationship in the southern African regions and the connection between the two rainfall zones are observed, for example during the 1950s. Our results confirm the complex interplay between large-scale teleconnections, regional SSTs and local effects in modulating multi-decadal southern African rainfall variability over long timescales.

The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

This study investigates the characteristics of the quasi 16-day wave in the mesosphere during boreal winter 2011/2012 using observations of water vapor from ground-based microwave radiometers and satellite data. The ground-based microwave radiometers are located in Seoul (South Korea, 37° N), Bern (Switzerland, 47° N) and Sodankylä (Finland, 67° N). The quasi 16-day wave is observed in the mesosphere at all three locations, while the dominant period increases with latitude from 15 days at Seoul to 20 days at Sodankylä. The observed evolution of the quasi 16-day wave confirms that the wave activity is strongly decreased during a sudden stratospheric warming that occurred in mid-January 2012. Using satellite data from the Microwave Limb Sounder on the Aura satellite, we examine the zonal characteristics of the quasi 16-day wave and conclude that the observed waves above the mid-latitudinal stations Seoul and Bern are eastward-propagating s=−1 planetary waves with periods of 15 to 16 days, while the observed oscillation above the polar station Sodankylä is a standing oscillation with a period of approximately 20 days. The strongest relative wave amplitudes in water vapor during the investigated time period are approximately 15%. The wave activity varies strongly along a latitude circle. The activity of the quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012 is strongest over Northern Europe, the North Atlantic ocean and North-West Canada. The region of highest wave activity seems to be related to the position of the polar vortex. We conclude that the classic approach to characterize planetary waves zonally averaged along a latitude circle is not sufficient to explain the local observations because of the strong longitudinal dependence of the wave activity.

The response of four winter wheat (Triticum aestivum L.) varieties to field water deficit: leaf anti-oxidative protection and proteolytic activity

Introduction: Drought is one of the most significant factors that limit plant productivity. Oxidative stress is a secondary event in many unfavorable environmental conditions. Intracellular proteases have a role in the metabolism reorganisation and nutrient remobilization under stress. In order to under stand the relative significance of oxidative stress and proteolysis in the yield reduction under drought, four varieties of Triticum aestivum L. with different field drought resistance were examined. Methods: A two-year field experiment was conducted. Analyses were performed on the upper most leaf of control plants and plants under water deficitat the stages most critical for yield reduction under drought (from jointing till milk ripeness). Leaf water deficit and electrolyte leakage, malondyaldehyde level, activities and isoenzymes of superoxide dismutase, catalase and peroxidase, leaf protein content and proteolytic activity were studied. Yield components were analyzed. Results: A general trend of increasing the membrane in stability and accumulation of lipid hydroperoxides was observed with some differences among varieties, especially under drought. The anti-oxidative enzyme activities were progressively enhanced, as well as the azocaseinolytic activities. The leaf protein content decreased under drought at the last phase. Differences among varieties were observed in the parameters under study. They were compared to yield components` reduction under water deprivation.