The Impact of the Extreme Winter 2015/16 Arctic Cyclone on the Barents-Kara Seas

Atmospheric data from the Atmospheric Infrared Sounder (AIRS) were used to study an extreme warm and humid air mass transported over the Barents–Kara Seas region by an Arctic cyclone at the end of December 2015. Temperature and humidity in the region was ~10°C (>3σ above the 2003–14 mean) warmer and ~1.4 g kg−1 (>4σ above the 2003–14 mean) wetter than normal during the peak of this event. This anomalous air mass resulted in a large and positive flux of energy into the surface via the residual of the surface energy balance (SEB), compared to the weakly negative SEB from the surface to the atmosphere expected for that time of year. The magnitude of the downwelling longwave radiation during the event was unprecedented compared to all other events detected by AIRS in December/January since 2003. An approximate budget scaling suggests that this anomalous SEB could have resulted in up to 10 cm of ice melt. Thinning of the ice pack in the region was supported by remotely sensed and modeled estimates of ice thickness change. Understanding the impact of this anomalous air mass on a thinner, weakened sea ice state is imperative for understanding future sea ice–atmosphere interactions in a warming Arctic

Sea ice and the ocean mixed layer over the Antarctic continental shelf

In this thesis, a modelling approach is taken to investigate the sea ice and ocean mixed layer over the Antarctic continental shelf. A primary motivation is to understand why the Amundsen and Bellingshausen (AB) shelf seas are flooded by Circumpolar Deep Water that is several degrees Celsius warmer than the cold shelf waters prevalent in the Weddell and Ross (WR) seas. An idealised sea ice-mixed layer model is used to investigate this apparent bimodal distribution. The formation of shelf waters (fully mixed water column) is shown to be driven primarily by the ‘cold’ WR atmospheric forcing, independent of the ocean profile, suggesting that the regional difference in atmospheric forcing alone is sufficient and perhaps necessary to account for the bimodal distribution in shelf sea temperature. Coupling the mixed layer model to the sea ice model CICE extends the study to the entire Southern Ocean, and provides a more accurate representation of the sea ice and the processes controlling mixed layer deepening within the shelf seas. The model captures well the expected sea ice thickness distribution, and produces deep (>500 m) mixed layers in the WR shelf seas each winter. Shallower wintertime mixed layers are produced in the AB seas. Deconstructing the surface mechanical power input to the mixed layer, shows that the salt flux from sea ice growth/melt dominates the evolution of the mixed layer in all four shelf seas. An analysis of the sea ice mass balance demonstrates the contrasting mean annual ice growth, melt and export within each of the four shelf seas. The CICE-mixed layer model is also used to investigate recent and future trends in the sea ice and mixed layer. The recent ERA-Interim forced simulation compares well with the observed regional trends in ice concentration, but shows mainly insignificant trends in the sea ice, the surface inputs of salt and heat, and the mixed layer depth over the shelf seas. The future HadGEM2-ES forced simulation shows, in-contrast, significant declines in the sea ice, the surface inputs of salt and heat and the mixed layer depth over the shelf seas. This simulation, however, shows poor agreement with recently observed sea ice trends; highlighting the on-going inability of climate models to accurately simulate Antarctic climate trends

Skillful spring forecasts of September Arctic sea ice extent using passive microwave sea ice observations

In this study, we demonstrate skillful spring forecasts of detrended September Arctic sea ice extent using passive microwave observations of sea ice concentration (SIC) and melt onset (MO). We compare these to forecasts produced using data from a sophisticated melt pond model, and find similar to higher skill values, where the forecast skill is calculated relative to linear trend persistence. The MO forecasts shows the highest skill in March–May, while the SIC forecasts produce the highest skill in June–August, especially when the forecasts are evaluated over recent years (since 2008). The high MO forecast skill in early spring appears to be driven primarily by the presence and timing of open water anomalies, while the high SIC forecast skill appears to be driven by both open water and surface melt processes. Spatial maps of detrended anomalies highlight the drivers of the different forecasts, and enable us to understand regions of predictive importance. Correctly capturing sea ice state anomalies, along with changes in open water coverage appear to be key processes in skillfully forecasting summer Arctic sea ice

Neutrophils: the forgotten cell in JIA disease pathogenesis

Juvenile idiopathic arthritis (JIA) has long been assumed to be an autoimmune disease, triggered by aberrant recognition of "self" antigens by T-cells. However, systems biology approaches to this family of diseases have suggested complex interactions between innate and adaptive immunity that underlie JIA. In particular, new data suggest an important role for neutrophils in JIA pathogenesis. In this short review, we will discuss the new data that support a role for neutrophils in JIA, discuss regulatory functions that link neutrophils to adaptive immune responses, and discuss future areas of investigation. Above all else, we invite the reader to re-consider the use of the term "autoimmunity" as applied to the family of illnesses we collectively call JIA

In-Depth Analysis of the Antibody Response of Individuals Exposed to Primary Dengue Virus Infection

Humans who experience a primary dengue virus (DENV) infection develop antibodies that preferentially neutralize the homologous serotype responsible for infection. Affected individuals also generate cross-reactive antibodies against heterologous DENV serotypes, which are non-neutralizing. Dengue cross-reactive, non-neutralizing antibodies can enhance infection of Fc receptor bearing cells and, potentially, exacerbate disease. The actual binding sites of human antibody on the DENV particle are not well defined. We characterized the specificity and neutralization potency of polyclonal serum antibodies and memory B-cell derived monoclonal antibodies (hMAbs) from 2 individuals exposed to primary DENV infections. Most DENV-specific hMAbs were serotype cross-reactive and weakly neutralizing. Moreover, many hMAbs bound to the viral pre-membrane protein and other sites on the virus that were not preserved when the viral envelope protein was produced as a soluble, recombinant antigen (rE protein). Nonetheless, by modifying the screening procedure to detect rare antibodies that bound to rE, we were able to isolate and map human antibodies that strongly neutralized the homologous serotype of DENV. Our MAbs results indicate that, in these two individuals exposed to primary DENV infections, a small fraction of the total antibody response was responsible for virus neutralization

Cloud Coverage Acts as an Amplifier for Ecological Light Pollution in Urban Ecosystems

The diurnal cycle of light and dark is one of the strongest environmental factors for life on Earth. Many species in both terrestrial and aquatic ecosystems use the level of ambient light to regulate their metabolism, growth, and behavior. The sky glow caused by artificial lighting from urban areas disrupts this natural cycle, and has been shown to impact the behavior of organisms, even many kilometers away from the light sources. It could be hypothesized that factors that increase the luminance of the sky amplify the degree of this “ecological light pollution”. We show that cloud coverage dramatically amplifies the sky luminance, by a factor of 10.1 for one location inside of Berlin and by a factor of 2.8 at 32 km from the city center. We also show that inside of the city overcast nights are brighter than clear rural moonlit nights, by a factor of 4.1. These results have important implications for choronobiological and chronoecological studies in urban areas, where this amplification effect has previously not been considered

Ultrasonography and color Doppler in juvenile idiopathic arthritis: diagnosis and follow-up of ultrasound-guided steroid injection in the wrist region. A descriptive interventional study

<p>Abstract</p> <p>Background</p> <p>The wrist region is one of the most complex joints of the human body. It is prone to deformity and functional impairment in juvenile idiopathic arthritis (JIA), and is difficult to examine clinically. The aim of this study was to evaluate the role of ultrasonography (US) with Doppler in diagnosis of synovitis, guidance of steroid injections, and follow-up examinations of the wrist in JIA.</p> <p>Methods</p> <p>In 11 patients (median age 12.5 years, range 2-16), 15 wrists with clinically active arthritis were assessed clinically by US and color Doppler (Logiq 9, GE, 16-4 MHz linear transducer) prior to and 1 and 4 weeks after US-guided steroid injection.</p> <p>Results</p> <p>US detected synovitis in the radio-carpal joints, the midcarpal joints, and the tendon sheaths in 87%, 53% and 33% of the wrists, respectively. Multiple compartments were involved in 67%. US-guidance allowed accurate placement of steroid in all 21 injected compartments, with a low rate of subcutaneous atrophy. Synovial hypertrophy was normalized in 86% of the wrists, hyperemia in 91%, and clinically active arthritis in 80%.</p> <p>Conclusions</p> <p>US enabled detection of synovial inflammation in compartments that are difficult to evaluate clinically and exact guidance of injections, and it was valuable for follow-up examinations. Normalization of synovitis was achieved in most cases, which supports the notion that US is an important tool in management of wrist involvement in JIA.</p

Natural Strain Variation and Antibody Neutralization of Dengue Serotype 3 Viruses

Dengue viruses (DENVs) are emerging, mosquito-borne flaviviruses which cause dengue fever and dengue hemorrhagic fever. The DENV complex consists of 4 serotypes designated DENV1-DENV4. Following natural infection with DENV, individuals develop serotype specific, neutralizing antibody responses. Monoclonal antibodies (MAbs) have been used to map neutralizing epitopes on dengue and other flaviviruses. Most serotype-specific, neutralizing MAbs bind to the lateral ridge of domain III of E protein (EDIII). It has been widely assumed that the EDIII lateral ridge epitope is conserved within each DENV serotype and a good target for vaccines. Using phylogenetic methods, we compared the amino acid sequence of 175 E proteins representing the different genotypes of DENV3 and identified a panel of surface exposed amino acids, including residues in EDIII, that are highly variant across the four DENV3 genotypes. The variable amino acids include six residues at the lateral ridge of EDIII. We used a panel of DENV3 mouse MAbs to assess the functional significance of naturally occurring amino acid variation. From the panel of antibodies, we identified three neutralizing MAbs that bound to EDIII of DENV3. Recombinant proteins and naturally occurring variant viruses were used to map the binding sites of the three MAbs. The three MAbs bound to overlapping but distinct epitopes on EDIII. Our empirical studies clearly demonstrate that the antibody binding and neutralization capacity of two MAbs was strongly influenced by naturally occurring mutations in DENV3. Our data demonstrate that the lateral ridge “type specific” epitope is not conserved between strains of DENV3. This variability should be considered when designing and evaluating DENV vaccines, especially those targeting EDIII