ALBERT

Description: Inflammatory immune cells, when activated, display much the same metabolic profile as a glycolytic tumor cell. This involves a shift in metabolism away from oxidative phosphorylation towards aerobic glycolysis, a phenomenon known as the Warburg effect. The result of this change in macrophages is to rapidly provide ATP and metabolic intermediates for the biosynthesis of immune and inflammatory proteins. In addition, a rise in certain tricarboxylic acid cycle intermediates occurs notably in citrate for lipid biosynthesis, and succinate, which activates the transcription factor Hypoxia-inducible factor. In this review we take a look at the emerging evidence for a role for the Warburg effect in the immune and inflammatory responses. The reprogramming of metabolic pathways in macrophages, dendritic cells, and T cells could have relevance in the pathogenesis of inflammatory and metabolic diseases and might provide novel therapeutic strategies. Recent studies reveal that inflammatory cells, when activated, display similar metabolic traits as cancer cells. During an inflammatory response or infection pro-inflammatory immune cells can shift their metabolism away from oxidative phosphorylation towards a high rate of glycolysis, a phenomenon known as the Warburg effect.

Description: The near-surface air temperature lapse rate is an important tool for spatially distributing temperatures in snow- and ice-melt models, but is difficult to parameterize, as it is not simply correlated with boundary-layer meteorological variables, such as temperature itself. This contribution quantifies spring-autumn lapse rate variability over 5 years at Vestari-Hagafellsjökull, a southerly outlet of Langjökull in Iceland. It is observed that summer lapse rates (0.57 °C 100 m −1 ) are significantly lower than non-summer rates, and are also lower than the Saturated Adiabatic Lapse Rate (SALR), which is often adopted in melt models. This is consistent with reduced near-surface temperature sensitivity to free-atmosphere temperature change during the occurrence of melting. A Variable Lapse Rate (VLR) regression model is calibrated with standardized, 750 hPa temperature anomalies derived from ERA-Interim climatology, which is shown to be highly significantly correlated with near-surface temperatures. The modelled VLR overestimates cumulative June–September Positive Degree Days (PDDs) by 3% when used to extrapolate temperatures from 1100 to 500 m a.s.l. on the glacier, whereas the SALR overestimates cumulative PDDs by 14%. ERA-Interim data therefore appear to offer a good representation of free-atmosphere temperature variability over Vestari-Hagafellsjökull, and the modelling approach offers a simple means of improving lapse rate parameterizations in melt models. Copyright © 2012 Royal Meteorological Society

Description: The near-surface air temperature lapse rate is an important tool for spatially distributing temperatures in snow- and ice-melt models, but is difficult to parameterize, as it is not simply correlated with boundary-layer meteorological variables, such as temperature itself. This contribution quantifies spring-autumn lapse rate variability over 5 years at Vestari-Hagafellsjökull, a southerly outlet of Langjökull in Iceland. It is observed that summer lapse rates (0.57 °C 100 m −1 ) are significantly lower than non-summer rates, and are also lower than the Saturated Adiabatic Lapse Rate (SALR), which is often adopted in melt models. This is consistent with reduced near-surface temperature sensitivity to free-atmosphere temperature change during the occurrence of melting. A Variable Lapse Rate (VLR) regression model is calibrated with standardized, 750 hPa temperature anomalies derived from ERA-Interim climatology, which is shown to be highly significantly correlated with near-surface temperatures. The modelled VLR overestimates cumulative June–September Positive Degree Days (PDDs) by 3% when used to extrapolate temperatures from 1100 to 500 m a.s.l. on the glacier, whereas the SALR overestimates cumulative PDDs by 14%. ERA-Interim data therefore appear to offer a good representation of free-atmosphere temperature variability over Vestari-Hagafellsjökull, and the modelling approach offers a simple means of improving lapse rate parameterizations in melt models. Copyright © 2012 Royal Meteorological Society

Description: Accounting for ontogenetic shifts and subregional differences in groundfish distributional responses to warm temperatures, we examined large, quality‐controlled datasets of depth‐stratified, random bottom trawl surveys conducted during summer in three large regions—the Gulf of Alaska and the west coasts of Canada and the US—over the period 1996–2015. Abundant commercial groundfish demonstrated poleward responses to warming temperatures only in a few subregions and moved shallower or deeper to seek colder waters depending on the subregion. They may form geographically distinct thermal ecoregions, instead of continuously moving northward along the northeast Pacific shelf under global warming. Abstract Although climate‐induced shifts in fish distribution have been widely reported at the population level, studies that account for ontogenetic shifts and subregional differences when assessing responses are rare.In this study, groundfish distributional changes in depth, latitude, and longitude were assessed at different size classes by species within nine subregions. We examined large, quality‐controlled datasets of depth‐stratified‐random bottom trawl surveys conducted during summer in three large regions—the Gulf of Alaska and the west coasts of Canada and the United States—over the period 1996–2015, a time period punctuated by a marine “heat wave.” Temporal biases in bottom temperature were minimized by subdividing each region into three subregions, each with short‐duration surveys. Near‐bottom temperatures, weighted by stratum area, were unsynchronized across subregions and exhibited varying subregional interannual variability. The weighted mean bottom depths in the subregions also vary largely among subregions. The centroids (centers of gravity) of groundfish distribution were weighted with catch per unit effort and stratum area for 10 commercially important groundfish species by size class and subregion. Our multivariate analyses showed that there were significant differences in aggregate fish movement responses to warm temperatures across subregions but not among species or sizes. Groundfish demonstrated poleward responses to warming temperatures only in a few subregions and moved shallower or deeper to seek colder waters. The temperature responses of groundfish depended on where they were. Under global warming, groundfish may form geographically distinct thermal ecoregions along the northeast Pacific shelf. Shallow‐depth species exhibited greatly different distributional responses to temperature changes across subregions while deep‐depth species of different subregions tend to have relatively similar temperature responses. Future climate studies would benefit by considering fish distributions on small subregional scales.

Description: The performance of temperature-index melt models is particularly affected by the choice of near-surface lapse rate used to determine the sum of positive daily temperatures at different elevations, and by the choice of factor used to relate this sum to the rate of melting. Data from the Langjökull ice cap are here used to quantify the influence of lapse-rate and degree-day factor variation on temperature-index melt simulations. The lapse rate was significantly lower during summer than in spring or autumn, as a result of diabatic cooling, reducing boundary-layer sensitivity to free-air temperature change. The summer lapse rate was also significantly lower than the Saturated Adiabatic Lapse Rate (SALR). A sensitivity of around 600 mm w.e. cumulative June–August melt per 0.1 °C 100 m –1 change in lapse rate was found across a 500 m altitude range. The sensitivity to a 1 mm w.e. °C –1  d –1 change in DDF varied more: from about 500 mm w.e. cumulative summer melt at low elevation, to about 200 mm w.e. at high elevation, reflecting the decline in melt rates associated with the greater persistence of snow with increasing altitude. The determination of a DDF for snow is complicated by the densification of the ageing snowpack, but the application of a parameterization for near-surface density based on albedo helped account for the development of snow water-equivalence. Lapse rate was parameterized as a function of standardized anomalies in 750 hPa re-analysis temperature, and significantly improved simulation of cumulative summer melt compared to models applying the SALR. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Bottom-up metabolic systems biology is of particular relevance to biochemists. The jargon of bottom-up metabolic systems biology however represents a major obstacle that needs to be overcome by a prospective practitioner in this emerging field. Herein, we diminish this early hurdle by providing a lexicon of the most important terms.

Description: Temperature-index models are widely favoured as a pragmatic means of simulating glacier melt due to their generally good performance, computational simplicity, and limited demands for in-situ data. However, their coefficients are normally treated as temporally stationary, unrealistically assuming a constancy of the prevailing weather. We address this simplification by prescribing model coefficients as a function of synoptic weather type, in a procedure that utilizes reanalysis data and preserves the minimal data requirements of temperature-index models. Using a cross-validation procedure at Vestari Hagafellsjökull, Iceland, and Storglaciären, Sweden, we demonstrate that applying transient model coefficients, for three temperature-index models, results in statistically-significant increases in the skill with which melt is modelled: median simulation improvements in the Nash-Sutcliffe Efficiency Coefficient of 7.3% and 23.6% are achieved when hourly and daily melt totals are evaluated, respectively. Our weather-type modelling approach also yields insight to processes driving parameter variability, revealing dependencies which are consistent with a priori considerations of the surface energy balance (SEB). We conclude that incorporating weather types into temperature-index models holds promise for improving their performance, as well as enhancing understanding variability in coefficient values. This article is protected by copyright. All rights reserved.

Description: ABSTRACT The surface energy balance (SEB) of glaciers, although of considerable importance for understanding the melt response to climate change, is rarely analysed for more than a few melt seasons due to the logistical challenges of meteorological measurement campaigns on glaciers. Insight into low-frequency (inter-decadal) changes in the SEB in response to climate warming and variable atmospheric circulation patterns has thus been limited. Here this problem is addressed by using ERA-Interim reanalysis data to extend glacier-meteorological records at two locations on Vestari Hagafellsjökull (Iceland) for the period 1979–2012. Trend analysis is conducted for this series before the role of synoptic circulation in modulating surface energetics is investigated. The results indicate that potential melt energy has increased significantly throughout the period of simulation at both locations (by 19.7 and 32.4%), with the largest increase evident for the turbulent heat fluxes (36.3 and 93.1%). The synoptic conditions associated with the recent high melt rates on the proximate Greenland Ice Sheet (GrIS) do not result in similarly extreme melt conditions for our Icelandic location. We also find that the North Atlantic Oscillation Index is significantly correlated with the radiative and latent heat components of the SEB. This association remains hidden if the melt rate is assessed in isolation, highlighting the utility of the SEB approach presented here for assessing synoptic aspects of glacier-climate interactions.

Description: Macrobrachium rosenbergii , the giant freshwater prawn, is an important source of high quality protein and occurs naturally in rivers as well as commercial farms in South and South-East Asia, including Bangladesh. This study investigated the genetic variation and population structure of M. rosenbergii sampled from four rivers in Bangladesh (sample size ranged from 19 to 20), assessing sequence variation, both in the mitochondrial cytochrome oxidase subunit 1 (CO1) gene and in 106 single nucleotide polymorphisms (SNPs) sampled randomly from the genome with double digest RAD sequencing (ddRADseq). The mitochondrial variation presented a shallow genealogy with high haplotype diversity ( h  =   0.95), reflecting an expansion in population size for the last ~82 kyr. Based on the CO1 variation the current effective population size ( N e ) was 9.7 × 10 6 (CI: 1.33 × 10 6 – 35.84 × 10 6 ) individuals. A significant population differentiation was observed with the mitochondrial CO1 sequence variation and based on the ddRADseq variation, which could be traced to the divergence of the population in the Naf River in the South-East border with Myanmar from the other populations. A differentiation in mtDNA haplotype frequencies was also observed between the Biskhali River and the Karnaphuli Rivers in eastern Bangladesh. This study demonstrated the use of high-throughput genotyping based on the ddRADseq method to reveal population structure at a small geographical scale for an important freshwater prawn. The information from this study can be utilized for management and conservation of this species in Bangladesh. The mitochondrial variation presented a shallow genealogy with high haplotype diversity ( h  = 0.95), reflecting an expansion in population size for the last ~82 kyr. Mitochondrial CO1 sequence variation revealed that the population of the Bishkhali River in western Bangladesh was distinct from the Naf and the Karnaphuli rivers in eastern Bangladesh. Genetic diversity estimated from ddRADseq was high and SNP variation revealed at least two distinct populations of M. rosenbergii sampled from Bangladesh: first, in the Naf River in between Bangladesh and Myanmar, and the second, in the Meghna, Bishkhali, and the Karnaphuli rivers.

Description: [1]  In total, Icelandic ice caps contain ~3,600 km 3 of ice, which if melted would raise sea level by ~1 cm. Here, we present an overview of mass changes of Icelandic ice masses since the end of the 19th century. They have both gained and lost mass during this period. Changes in ice volume have been estimated both through surface mass balance measurements (performed annually since ~1990) and differencing of digital elevation models derived from various satellite and airborne observations. While the glaciers showed little mass loss as the 20th century began, losses increased rapidly after 1925, peaked in the 1930s and 1940s and remained significant until the 1960s. After being near-zero or even positive during the 1980s andearly 1990s, glacier mass budgets declined considerably, and have since the mid-1990s shown an average annual loss of 9.5 ± 1.5 Gt a –1 , contributing ~0.03 mm a –1 to sea level rise. Since 1995 inter-annual variability in mass loss is high, ranging from 2.7 to 25.3 ± 1.5 Gt a –1 , corresponding to surface mass balances of -0.2 to -2.2 ± 0.15 m we a –1 . This variability is driven by climate fluctuations and also by transient reduction of albedo due to volcanic eruptions.