(Table 1) Organohalogen contaminants in adipose tissue of captive sledge dogs (Canis familiaris) fed with whale blubber or pork fat

Studies on the fate of organohalogen contaminants (OHCs) in wild top predator mammals in the Arctic have often been a challenge due to important knowledge deficiencies in the life history of the sampled animals. The present study investigated the influence of age, dietary and trans-generational factors on the fate of major lipophilic chlorinated and brominated OHCs in adipose tissue of a potential surrogate captive species for the polar bear (Ursus maritimus), the sledge dog (Canis familiaris) in West Greenland. Adult female sledge dogs (P) and their sexually-mature (F1) and/or pre-weaning pups (F1-MLK) were divided into an exposed group (EXP) fed blubber from a Greenland minke whale (Balaenoptera acutorostrata) and a control group (CON) given commercially available pork fat. Large dietary treatment-related differences in summed and individual congener/compound adipose tissue concentrations of polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), chlordanes (CHLs) and polychlorinated biphenyls (PCBs) were found between the EXP and CON groups for all the sledge dog cohorts. However, among the F1-MLK, F1 and P dogs in both of the EXP and CON groups, little or no difference existed in PBDE, HCB, CHL and PCB concentrations, suggesting higher state of equilibrium in adipose tissue concentrations from a very early stage of life. In contrast, the distribution pattern (proportions to the summed concentrations) of OHC classes, and the major congeners/ compounds constituting those classes, varied on a dietary group- and/or cohort-dependent manner. The present captive sledge dog study demonstrated the importance of the confounding effects of diet composition, mother-pup association (maternal transfer), reproductive status (nursing), and to a lesser extent age in the fate of OHCs in adipose tissue of a large top carnivore mammal.

(Table 2) Radiocarbon ages on Arctic box and multicores

Paleo-sea-ice history in the Arctic Ocean was reconstructed using the sea-ice dwelling ostracode Acetabulastoma arcticum from late Quaternary sediments from the Mendeleyev, Lomonosov, and Gakkel Ridges, the Morris Jesup Rise and the Yermak Plateau. Results suggest intermittently high levels of perennial sea ice in the central Arctic Ocean during Marine Isotope Stage (MIS) 3 (25-45 ka), minimal sea ice during the last deglacial (16-11 ka) and early Holocene thermal maximum (11-5 ka) and increasing sea ice during the mid-to-late Holocene (5-0 ka). Sediment core records from the Iceland and Rockall Plateaus show that perennial sea ice existed in these regions only during glacial intervals MIS 2, 4, and 6. These results show that sea ice exhibits complex temporal and spatial variability during different climatic regimes and that the development of modern perennial sea ice may be a relatively recent phenomenon.

(Table 2) AMS radiocarbon dates from sediment cores obtained during James Clark Ross cruise JR142, Kvitøya Trough

High-resolution geophysical and sediment core data are used to investigate the pattern and dynamics of former ice flow in Kvitøya Trough, northwestern Barents Sea. A new swath-bathymetric dataset identifies three types of submarine landform in the study area (streamlined landforms, meltwater channels and cavities, iceberg scours). Subglacially produced streamlined landforms provide a record of ice flow through Kvitøya Trough during the last glaciation. Flow directions are inferred from the orientations of streamlined landforms (drumlins, crag-and-tail features). Ice flowed northward for at least 135 km from an ice divide at the southern end of Kvitøya Trough. A large channel-cavity system incised into bedrock in the southern trough indicates that subglacial meltwater was present at the former ice-sheet base. Modest landform elongation ratios and a lack of mega-scale glacial lineations suggest that, although ice in Kvitøya Trough was melting at the bed and flowed faster than the likely thin and cold-based ice on adjacent banks, a major ice stream probably did not occupy the trough. Retreat was relatively rapid after 14-13.5 14C kyr B.P. and probably progressed via ice sheet-bed decoupling in response to rising sea level. There is little evidence for still stands during ice retreat or of ice-proximal deglacial sediments. Relict iceberg scours in present-day water depths of more than 350 m in the northern trough indicate that calving was an important mass loss mechanism during retreat.

Foraminifera in sediment cores of the Lomonosov Ridge and Morris Jesup Rise

X-ray fluorescence (XRF) scanning of sediment cores from the Lomonosov Ridge and the Morris Jesup Rise reveals a distinct pattern of Ca intensity peaks through Marine Isotope Stages (MIS) 1 to 7. Downcore of MIS 7, the Ca signal is more irregular and near the detection limit. Virtually all major peaks in Ca coincide with a high abundance of calcareous microfossils; this is particularly conspicuous in the cores from the central Arctic Ocean. However, the recorded Ca signal is generally caused by a combination of biogenic and detrital carbonate, and in areas influenced by input from the Canadian Arctic, detrital carbonates may effectively mask the foraminiferal carbonates. Despite this, there is a strong correlation between XRF-detected Ca content and foraminiferal abundance. We propose that in the Arctic Ocean north of Greenland a common palaeoceanographic mechanism is controlling Ca-rich ice-rafted debris (IRD) and foraminiferal abundance. Previous studies have shown that glacial periods are characterized by foraminfer-barren sediments. This implies that the Ca-rich IRD intervals with abundant foraminifera were most likely deposited during interglacial periods when glaciers left in the Canadian Arctic Archipelago were still active and delivered a large amount of icebergs. At the same time, conditions were favourable for planktic foraminifera, resulting in a strong covariance between these proxies. Therefore, we suggest that the XRF scanner's capability to efficiently map Ca concentrations in sediment cores makes it possible to systematically examine large numbers of cores from different regions to investigate the palaeoceanographic reasons for the calcareous microfossils' spatial and temporal variability.

A versatile synthetic approach to peptidyl privileged structures using a "safety-catch" linker

Peptidyl privileged structures have been widely used by many groups to discover biologically active molecules. In this context, privileged substructures are used as hydrophobic anchors, to which peptide functionality is appended to gain specificity. Utilization of this concept has led to the discovery of many different active compounds at a wide range of biological receptors. A synthetic approach to these compounds has been developed on a safety-catch linker that allows rapid preparation of large libraries of these molecules. Importantly, amide bond formation/cleavage through treatment with amines is the final step; it is a linker strategy that allows significant diversification to be easily incorporated, and it only requires the inclusion of an amide bond. In addition, chemistry has been developed that permits the urea moiety to be inserted at the N-terminus of the peptide, allowing the same set of amines (either privileged substructures or amino acid analogues) to be used at both the N- and C-termini of the molecule. To show the robustness of this approach, a small library of peptidyl privileged structures were synthesized, illustrating that large combinatorial libraries can be synthesized using these technologies.

VHITS: Vertical handoff initiation and target selection in a heterogeneous wireless network

Global connectivity, for anyone, at anyplace, at anytime, to provide high-speed, high-quality, and reliable communication channels for mobile devices, is now becoming a reality. The credit mainly goes to the recent technological advances in wireless communications comprised of a wide range of technologies, services, and applications to fulfill the particular needs of end-users in different deployment scenarios (Wi-Fi, WiMAX, and 3G/4G cellular systems). In such a heterogeneous wireless environment, one of the key ingredients to provide efficient ubiquitous computing with guaranteed quality and continuity of service is the design of intelligent handoff algorithms. Traditional single-metric handoff decision algorithms, such as Received Signal Strength (RSS) based, are not efficient and intelligent enough to minimize the number of unnecessary handoffs, decision delays, and call-dropping and/or blocking probabilities. This research presented a novel approach for the design and implementation of a multi-criteria vertical handoff algorithm for heterogeneous wireless networks. Several parallel Fuzzy Logic Controllers were utilized in combination with different types of ranking algorithms and metric weighting schemes to implement two major modules: the first module estimated the necessity of handoff, and the other module was developed to select the best network as the target of handoff. Simulations based on different traffic classes, utilizing various types of wireless networks were carried out by implementing a wireless test-bed inspired by the concept of Rudimentary Network Emulator (RUNE). Simulation results indicated that the proposed scheme provided better performance in terms of minimizing the unnecessary handoffs, call dropping, and call blocking and handoff blocking probabilities. When subjected to Conversational traffic and compared against the RSS-based reference algorithm, the proposed scheme, utilizing the FTOPSIS ranking algorithm, was able to reduce the average outage probability of MSs moving with high speeds by 17%, new call blocking probability by 22%, the handoff blocking probability by 16%, and the average handoff rate by 40%. The significant reduction in the resulted handoff rate provides MS with efficient power consumption, and more available battery life. These percentages indicated a higher probability of guaranteed session continuity and quality of the currently utilized service, resulting in higher user satisfaction levels.

(Table 1) Elemental mean values of the upper Paleocene and lower Eocene in IODP Hole 302-M0004A

We reconstruct the latest Paleocene and early Eocene (~57-50 Ma) environmental trends in the Arctic Ocean and focus on the Paleocene-Eocene thermal maximum (PETM) (~55 Ma), using strata recovered from the Lomonosov Ridge by the Integrated Ocean Drilling Program Expedition 302. The Lomonosov Ridge was still partially subaerial during the latest Paleocene and earliest Eocene and gradually subsided during the early Eocene. Organic dinoflagellate cyst (dinocyst) assemblages point to brackish and productive surface waters throughout the latest Paleocene and early Eocene. Dinocyst assemblages are cosmopolitan during this time interval, suggesting warm conditions, which is corroborated by TEX86'-reconstructed temperatures of 15°-18°C. Inorganic geochemistry generally reflects reducing conditions within the sediment and euxinic conditions during the upper lower Eocene. Spectral analysis reveals that the cyclicity, recorded in X-ray fluorescence scanning Fe data from close to Eocene thermal maximum 2 (~53 Ma, presence confirmed by dinocyst stratigraphy), is related to precession. Within the lower part of the PETM, proxy records indicate enhanced weathering, runoff, anoxia, and productivity along with sea level rise. On the basis of total organic carbon content and variations in sediment accumulation rates, excess organic carbon burial in the Arctic Ocean appears to have contributed significantly to the sequestration of injected carbon during the PETM.

(Table 1) The 10Be and 9Be isotope record of IODP EXP202 composite Site

The upper 200 m of the sediments recovered during IODP Leg 302, the Arctic Coring Expedition (ACEX), to the Lomonosov Ridge in the central Arctic Ocean consist almost exclusively of detrital material. The scarcity of biostratigraphic markers severely complicates the establishment of a reliable chronostratigraphic framework for these sediments, which contain the first continuous record of the Neogene environmental and climatic evolution of the Arctic region. Here we present profiles of cosmogenic 10Be together with the seawater-derived fraction of stable 9Be obtained from the ACEX cores. The down-core decrease of 10Be/9Be provides an average sedimentation rate of 14.5 ± 1 m/Ma for the uppermost 151 m of the ACEX record and allows the establishment of a chronostratigraphy for the past 12.3 Ma. The age corrected 10Be concentrations and 10Be/9Be ratios suggest the existence of an essentially continuous sea ice cover over the past 12.3 Ma.

Permafrost longterm monitoring sites (Arctic and Antarctic)

About 50 locations ('cold spots') where permafrost (Arctic and Antarctic) in situ monitoring has been taking place for many years or where field stations are currently established (through, for example the Canadian ADAPT program) have been identified. These sites have been proposed to WMO Polar Space Task Group as focus areas for future monitoring by satellite data. Seven monitoring transects spanning different permafrost types have been proposed in addition.

(Table 2) Mercury concentration in hair of Northwest Greenland polar bears (Ursus maritimus)

Hair samples from 117 Northwest Greenland polar bears (Ursus maritimus) were taken during 1892-2008 and analyzed for total mercury (hereafter Hg). The sample represented 28 independent years and the aim of the study was to analyze for temporal Hg trends. Mercury concentrations showed yearly significant increases of 1.6-1.7% (p < 0.0001) from 1892 to 2008 and the two most recent median concentrations from 2006 and 2008 were 23- to 27-fold higher respectively than baseline level from 1300 A.D. in the same region (Nuullit). This indicates that the present (2006-2008) Northwest Greenland polar bear Hg exposure is 95.6-96.2% anthropogenic in its origin. Assuming a continued anthropogenic increase, this model estimated concentrations in 2050 and 2100 will be 40- and 92-fold the baseline concentration, respectively, which is equivalent to a 97.5 and 98.9% man-made contribution. None of the 2001-2008 concentrations of Hg in Northwest Greenland polar bear hair exceeded the general guideline values of 20-30 µg/g dry weight for terrestrial wildlife, whereas the neurochemical effect level of 5.4 µg Hg/g dry weight proposed for East Greenland polar bears was exceeded in 93.5% of the cases. These results call for detailed effect studies in main target organs such as brain, liver, kidney, and sexual organs in the Northwest Greenland polar bears.