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Major changes in North Atlantic zooplankton communities in recent decades have been linked to climate change but the roles of environmental drivers are often complex. High temporal resolution data is required to disentangle the natural seasonal drivers from additional sources of variability in highly heterogeneous marine systems. Here, physical and plankton abundance data spanning 2003–2017 from a weekly long-term monitoring site on the west coast of Scotland were used to investigate the cause of an increasing decline to approximately -80± 5% in annual average total zooplankton abundance from 2011 to 2017. Generalized additive mixed models (GAMMs), with an autoregressive correlation structure, were used to examine seasonal and inter-annual trends in zooplankton abundance and their relationship with environmental variables. Substantial declines were detected across all dominant taxa, with ∼ 30–70% of the declines in abundance explained by a concurrent negative trend in salinity, alongside the seasonal cycle, with the additional significance of food availability found for some taxa. Temperature was found to drive seasonal variation but not the long-term trends in the zooplankton community. The reduction in salinity had the largest effect on several important taxa. Salinity changes could partly be explained by locally higher freshwater run-off driven by precipitation as well as potential links to changes in offshore water masses. The results highlight that changes in salinity, caused by either freshwater input (expected from climate predictions) or fresher offshore water masses, may adversely impact coastal zooplankton communities and the predators that depend on them.

Zooplankton phenological shifts may affect energy transfer through pelagic food web and up to fisheries, but few studies have compared zooplankton phenology across a wide latitudinal range of water temperatures. We examined the phenological variations of zooplankton at four sites along a latitudinal gradient from the Bay of Biscay [Bilbao and Urdaibai (BU)], the English Channel (Plymouth; L4), and the North Sea [Stonehaven (SH)] from 1999 to 2013. Zooplankton taxa showed interannual phenological variations that were opposite in direction between the southernmost BU and the northernmost SH sites. The East Atlantic pattern was the climate teleconnection best related to zooplankton phenological variations. Among local variables , salinity at BU was best related to phenological changes at BU as opposed to those at SH. Locally, chlorophyll a was most relevant at SH and temperature at L4. While we did see some imprints of temperature in causing expected directions of phenology shifts, i.e. towards earlier appearance of spring taxa and later appearance of autumn taxa in warm years, these patterns were by no means clear-cut. The dominant role of temperature in driving phenological variation suggested by some studies seems to be obscured by biotic and climatic controls acting differently along our environmental gradient.

Using the socio-ecological model, this qualitative study aimed to explore teachers’ perspectives on the barriers and facilitators to Fundamental Movement Skills (FMS) and physical activity engagement in children living in deprived areas in the UK. A purposive sample of 14 primary school teachers participated in semi-structured focus groups drawn from schools situated in lower SES wards and ethnically diverse areas in Central England. Thematic analysis of transcripts identified multiple and interrelated factors across all levels of the socio-ecological model for barriers to FMS and PA (i.e., intrapersonal, interpersonal, organisational, community and policy). Facilitators at three levels of influence were found (i.e., intrapersonal, interpersonal and organisational). We conclude, barriers and enablers to the PA and FMS in children from ethnically diverse backgrounds living in deprived areas are multifactorial and interrelated. At a school level, initiatives to increase PA and develop the FMS needed to be active are likely to be ineffective unless the barriers are addressed at all levels and considered more holistically with their complexity. Multi-disciplinary solutions are needed across sectors given the range of complex and interrelated factors.

Background/objectives: Vulval lichen sclerosus (VLS) is a chronic inflammatory skin condition predominantly affecting the anogenital region in women and children. To date, there is lack of agreement amongst experts on a severity scale to aid assessment, research and treatment stratification on VLS. Furthermore, literature on best practice for long-term management of VLS is lacking. The aim of this consensus is to provide broad guidelines on the short and long-term management of VLS. Methods: An initial focus group of Australasian experts in vulval dermatology developed a draft consensus statement for the management of VLS. Based on the results of the draft statement, a consensus panel of 22 Australasian experts, comprised of the initial and additional members, participated in an anonymous four-stage eDelphi process. Round 1 involved generation and voting on statements from the draft consensus statement developed by the focus group. In Rounds 2, 3 & 4, panel members were presented formal feedback from previous rounds and asked to indicate their level of agreement. Consensus was reached if there was ≥70% agreement on the importance of an item in the 4 (agree) to 5 (strongly agree) range. Results: The expert panel, with a total of 504 collective years of experience in the field of VLS, reached consensus on a core set of 51 management statements related to diagnosis, severity, initial and long-term management, follow-up, and complications of VLS. Conclusions: This study has identified a set of management statements for VLS that may be useful in clinical practice in the Australasian population.

Copepods are amongst the most abundant animals on our planet. Who knew?! These small (typically 1–10 mm) crustaceans are found in all of the world’s oceans and play an important role in regulating Earth’s climate. Like wildebeest in the Serengeti graze on grasslands and are food for lions, herbivorous copepods represent a vital link in oceanic food chains between microscopic algae and higher predators, such as fish, birds, and whales. A group of copepods called Calanus are particularly important in the Northern Hemisphere. These tiny-but-mighty animals also share the wildebeest’s need to make a large annual migration—but in their case, they sink thousands of meters downwards to spend the winter in the deep, dark ocean. Understanding the lives of marine copepods, and how their populations will respond to climate change, is crucial for predicting the future health of the marine environment and how it helps our planet.

Zooplankton seasonality and its environmental drivers were studied at four coastal sites within the Northeast Atlantic Shelves Province (Bilbao35 (B35) and Urdaibai35 (U35) in the Bay of Biscay, Plymouth L4 (L4) in the English Channel and Stonehaven (SH) in the North Sea) using time series spanning 1999–2013. Seasonal community patterns were extracted at the level of broad zooplankton groups and copepod and cladoceran genera using redundancy analysis. Temperature was generally the environmental factor that explained most of the taxa seasonal variations at the four sites. However, between-site differences related to latitude and trophic status (i.e. from oligotrophic to mesotrophic) were observed in the seasonality of zooplankton community, mainly in the pattern of taxa that peaked in spring-summer as opposed to late autumn-winter zooplankton, which were linked primarily to differences in the seasonal pattern of phytoplankton. The percentage of taxa variations explained by environmental factors increased with latitude and trophic status likely related to the increase in the co-variation of temperature and chlorophyll a, as well as in the increase in regularity of the seasonal patterns of both temperature and chlorophyll a from south to north, and of chlorophyll a with trophic status. Cladocerans and cirripede larvae at B35 and U35, echinoderm larvae at L4 and decapod larvae at SH made the highest contribution to shape the main mode of seasonal pattern of zooplankton community, which showed a seasonal delay with latitude, as well as with the increase in trophic status.

Contribution of latitude, distance offshore and environmental factors to variations in zooplankton assemblages across the Northeast Atlantic Shelves Province, from the Bay of Biscay [Bilbao 35 (B35) and Urdaibai 35 (U35)] to the English Channel (Plymouth L4; L4) and the North Sea (Stonehaven; SH), were assessed mainly by redundancy analysis. For coarse zooplankton groups latitude explained the main between-site differences, and meroplankton contributed more than holoplankton. Latitudinal differences were best indicated by contrasting abundances of cirripede larvae and doliolids (most abundant at the lowest latitude sites) and bryozoan and polychaete larvae (most abundant at the highest latitude site). Doliolids were best indicators of temperature-mediated latitudinal differences. The interaction between latitude and distance offshore or salinity and phytoplankton biomass explained smaller percentages of the variability. The main differences in copepod and cladoceran genera reflected the oceanic influence, with highest presence of Corycaeus and Oncaea at L4, likely related to the higher influence of off-shelf water intrusions, and neritic Acartia dominating at SH, U35 and B35. Podon and Evadne, which decreased from south to north, reflected latitude-related differences driven more by salinity than by temperature. Instances where a single species (e.g. Acartia clausi) dominated showed common relationships with temperature, consistent with a common thermal niche. Differences in co-generic species dominance between sites depicted the latitudinal gradient.

Zooplankton abundance series (1999–2013) from the coastal sites of Bilbao 35 (B35), Urdaibai 35 (U35), Plymouth L4 (L4) and Stonehaven (SH), in the Northeast Atlantic were compared to assess differences in the magnitude of seasonal, interannual and residual scales of variability, and in patterns of seasonal and interannual variation in relation to latitudinal location and trophic status. Results showed highest seasonal variability at SH consistent with its northernmost location, highest interannual variability at U35 associated to an atypical event identified in 2012 in the Bay of Biscay, and highest residual variability at U35 and B35 likely related to lower sampling frequency and higher natural and anthropogenic stress. Interannual zooplankton variations were not coherent across sites, suggesting the dominance of local influences over large scale environmental drivers. For most taxa the seasonal pattern showed coherent differences across sites, the northward delay of the annual peak being the most common feature. The between-site seasonal differences in spring–summer zooplankton taxa were related mainly to phytoplankton biomass, in turn, related to differences in latitude or anthropogenic nutrient enrichment. The northward delay in water cooling likely accounted for between-site seasonal differences in taxa that increase in the second half of the year.

We consider the problem of deciding whether a k-colored graph can be completed to have a given property. We establish that, when k is not fixed, the completion problems for (Helly) circular-arc graphs, even (Helly) proper or (Helly) unit circular-arc graphs, are NP-complete. When k is fixed, in the case of completion to a (Helly) circular-arc graph, (Helly) proper circular-arc graph, or (Helly) unit circular-arc graph we fully classify the complexities of the problems. We also show that deciding whether a 3-colored graph can be completed to be strongly chordal can be done in O(n2) time. As a corollary of our results, the sandwich problems for Helly circular-arc graphs, Helly proper circular-arc graphs, and Helly unit circular-arc graphs are NP-complete.

This study examined the inter-relationships between kittiwake breeding success and sandeel abundance, Calanus copepods, chlorophyll and temperature. The validity of past proxies of sandeel prey (Calanus and temperature) suggested in the literature was also examined. Winter temperature was not found to be a reliable indicator of the abundance of sandeel or lower trophic levels, although the present study did support past evidence for a dependence of kittiwake breeding success on local sandeel abundance as, with the exception of two years, there was a linear relationship with log age-0 sandeel abundance. The abundance of sandeel was positively linked to the dates of predicted peak egg abundance in C. finmarchicus and C. helgolandicus. This supported earlier evidence that the match with prey timing is important to sandeel recruitment. Neither Calanus species was associated with temperature in the February to March period nor in the April–May period, which may explain the lack of a temperature effect that propagates through the trophic levels. Consequently, although kittiwake breeding success appears to show some sensitivity and specificity to changes in their prey, this responsiveness was not found to extend to the lowest trophic level (Calanus abundance) or to temperature. As such kittiwake breeding success was not a reliable indicator of climate-driven changes in the local food web.

Ocean acidification (OA), the anthropogenic carbon dioxide-induced changes in seawater carbonate chemistry, is likely to have a significant impact on calcifying plankton. Most planktonic studies on OA are based on “one-off” cruises focused on offshore areas while observations from inshore waters are scarce. This study presents the first analysis on the shell integrity of pelagic gastropods (holoplanktonic pteropods and planktonic larvae of otherwise benthic species) at the Scottish Coastal Observatory monitoring site at Stonehaven on the east coast of Scotland. The shell integrity of archived pelagic gastropods specimens from 2011 to 2013 was examined using Scanning Electron Microscopy and the relationship with OA (pH and aragonite saturation, Ωarg) and other environmental parameters was investigated. Evidence of shell dissolution was detected in all analysed taxa even though the seawater was supersaturated with respect to aragonite. The shell condition matched the temporal pattern observed in Ωarg, with higher proportion of dissolution associated with decreasing Ωarg, suggesting that the seasonality component of carbonate chemistry might affect the shell integrity of pelagic gastropods. The proportion of shell dissolution differed significantly between larvae and adult stages of pteropods, supporting the hypothesis that early-life stages would be more vulnerable to OA-induced changes. Our data also suggest that sensitivity to OA may differ even between closely related taxonomic groups. The strong interannual variability revealed by the year-to-year shell dissolution and Ωarg illustrates the difficulty in assessing the plankton response to OA in the field and the value of time series studies.

Plankton are sensitive indicators of change and, at the base of marine food webs, they underpin important ecosystem services such as carbon sequestration and fisheries production. In the UK and the Northeast Atlantic region, change in plankton functional groups, or ‘lifeforms’, constructed based on biological traits, is the formally accepted policy indicator used to assess Good Environmental Status (GES) for pelagic habitats under the Marine Strategy Framework Directive (MSFD: 2008/56/EC). To identify changes in UK pelagic habitats, plankton lifeforms, were used from diverse UK data sets collected by different methods, including plankton sampling by nets, water bottles, integrating tube samplers, and the Continuous Plankton Recorder. A Plankton Index approach was used to identify change in plankton lifeforms. This is the first time that the pelagic plankton community has been assessed on a UK-wide scale and forms the foundation of the UK’s 2020 MSFD Assessment for pelagic habitat biodiversity and food webs. This approach revealed that some of the plankton lifeforms used in the assessment displayed spatially-variable changes during the past decade. Assessing plankton community change using a common indicator at the UK scale for the first time is a significant step towards evaluating GES for European seas. Determining GES for pelagic habitats, however, is a challenging process, with additional work required to interpret the assessment results and to identify causation of the changes observed.

Zooplankton on continental shelves represent an important intermediary in the transfer of energy and matter from phytoplankton to the wider ecosystem. Their taxonomic composition and trophic interactions with phytoplankton vary in space and time, and interpreting the implications of this constantly evolving landscape remains a major challenge. Here we combine plankton taxonomic data with the analysis of biovolume spectra and stable isotopes to provide insights into the trophic interactions that occur in a shelf sea ecosystem (Celtic Sea) across the spring-summer-autumn transition. Biovolume spectra captured the seasonal development of the zooplankton community well, both in terms of total biomass and trophic positioning, and matched trophic positions estimated by stable isotope analysis. In early April, large microplankton (63–200 µm) occupied higher trophic positions than mesozooplankton (>200 µm), likely reflecting the predominance of nanoplankton (2–20 µm) that were not readily available to mesozooplankton grazers. Biomass and number of trophic levels increased during the spring bloom as elevated primary production allowed for a higher abundance of predatory species. During July, the plankton assemblage occupied relatively high trophic positions, indicating important links to the microbial loop and the recycling of organic matter. The strong correlation between biomass and community trophic level across the study suggests that the Celtic Sea is a relatively enclosed and predominantly energy-limited ecosystem. The progression of the zooplankton biomass and community structure within the central shelf region was different to that at the shelf-break, potentially reflecting increased predatory control of copepods by macrozooplankton and pelagic fishes at the shelf break. We suggest that the combination of size spectra and stable isotope techniques are highly complementary and useful for interpreting the seasonal progression of trophic interactions in the plankton.

The copepod Eurytemora herdmani, native to coastal waters of the north-west Atlantic and north Pacific Oceans, was discovered at a marine sampling station in the Firth of Forth, Scotland, UK. The species was present in the summer zooplankton assemblage over three successive years. Peak abundance followed peak chlorophyll a concentration in surface waters. Given that previous studies on the Firth of Forth had only found species native to Europe, a survey of the Forth estuary was undertaken in summer 2014. Eurytemora herdmani was found at sampling stations where the salinity was greater than 20, while Eurytemora affinis was found at sampling stations with lower salinity further upstream. The impact of this introduction on the native zooplankton community is not known, and will require further study. The Firth of Forth has a high level of shipping traffic, and this species may have been introduced by ships’ ballast water.

This study presents the first comparative description of the physics, nutrients and plankton communities at two Scottish monitoring sites between 2003 and 2012; Stonehaven on the east coast of Scotland and Loch Ewe on the west coast. This description provides baseline information about the diversity of the plankton community in Scottish waters to support assessment of the plankton community for the EU Marine Strategy Framework Directive. Spring time temperatures at Loch Ewe were approximately 2 °C higher and the median secchi depth was almost 1 m greater than at Stonehaven during this period. Freshwater inflow from the river Ewe may promote water column stability at Loch Ewe. These factors may account for the earlier spring bloom observed at the Loch Ewe monitoring site. The seasonality of chlorophyll ‘a’ at Loch Ewe was typical of stratified waters in temperate regions with a strong spring/autumn peak attributed to increased numbers of diatoms whilst dinoflagellates dominated during the summer. At Stonehaven highest concentrations of chlorophyll were recorded between May and June and the autumn diatom bloom was considerably less than in Loch Ewe. A higher biomass of zooplankton grazers was found at Loch Ewe than at Stonehaven. Pseudocalanus was the dominant copepod at both sites, particularly during the spring period. Zooplankton carnivores were also more abundant at Loch Ewe than at Stonehaven and were dominated by cnidarians. Considerable interannual variability was observed in cnidarian abundance and diversity at both sites. Variation in the abundance of Ceratium, Calanus finmarchicus and Calanus helgolandicus at both sites followed similar trends in other time series suggesting that the plankton communities at Stonehaven and Loch Ewe are responding to large scale environmental influences.

Recent research has focused on the development of effective online problem based learning (PBL). However, there is a need for research to examine experiences of online PBL in those new to online learning. This study used a single module blended approach to examine the student experience of online PBL in a group of postgraduates new to online learning. This employed one problem scenario for each group (four students per group) as the central component of the module. Asynchronous discussion boards were used to facilitate the learning process with other forms of delivery used as appropriate. Focus group interviews revealed that students believed online PBL developed skills related to employability and information retrieval/evaluation. Online PBL was seen as beneficial for developing ideas and critiquing information. However, the artificial nature of the discussion board space was a barrier for some students, as was anxiety about online participation in the PBL tasks.

The efficacy of caffeine ingestion in enhancing aerobic performance is well established. The evidence for caffeine's effects on resistance exercise is mixed and has not fully examined the associated psychological and psychophysiological changes. This study examined acute effects of ingesting a caffeine-containing energy drink on repetitions to failure, the rating of perceived exertion (RPE), and the readiness to invest physical effort (RTIPE) and mental effort during resistance exercise to failure. Thirteen resistance-trained men took part in this double-blind, randomized cross-over experimental study whereby they ingested a caffeinated (179 mg) energy drink or placebo solution 60 minutes before completing a bout of resistance exercise comprising bench press, deadlift, prone row, and back squat exercise to failure at an intensity of 60% 1-repetition maximum. Experimental conditions were separated by at least 48 hours. Participants completed significantly greater repetitions to failure, irrespective of exercise, in the energy drink condition (p = 0.015). Rating of perceived exertion was significantly higher in the placebo condition (p = 0.02) and was significantly higher during lower-body exercises compared with upper-body exercises irrespective of the substance ingested (p = 0.0001). Readiness to invest mental effort was greater with the energy drink condition (p = 0.04), irrespective of time. A significant time × substance interaction (p = 0.036) for RTIPE indicated that RTIPE increased for both placebo and energy drink conditions preingestion to pre-exercise, but the magnitude of increase was greater with the energy drink condition compared with placebo. This resulted in higher RTIPE postexercise for the energy drink condition. These results suggest that acute ingestion of a caffeine-containing energy drink can enhance resistance exercise performance to failure and positively enhance psychophysiological factors related to exertion in trained men.

We examined how predicted end of century ocean warming and acidification scenarios affected the incidence of apoptosis in the eggs and nauplii of the copepod Calanus helgolandicus. Offspring viability was not affected by 1000 ppm CO2-acidified seawater, whereas the effects of 2 and 4°C warming were dependent upon the batch of eggs used; warming increased viability in the second batch. This context-dependency highlights the need for cautious interpretation and application of data from individual climate-change studies.

Summary 1. Marine copepods of the genus Calanus can reproduce prior to the spring bloom in the absence of sufficient food. Their starvation physiology, and hence the factors limiting their pre-bloom population growth (egg production), remain poorly understood. 2. Stoichiometric theory can provide insights into the factors controlling an organism’s growth and the fate of elements in an ecosystem. It is underpinned by substrate utilization efficiencies that relate to key physiological processes such as absorption efficiencies (AEs) and biomass turnover. These parameters are seldom investigated, particularly in the case of essential ‘micronutrients’ such as the polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). 3. Calanus spp. were fed briefly and subsequently starved for 5 days to determine basal turnover rates of biomass carbon, nitrogen and essential PUFAs. The effect of short-term fasting on nitrogen isotope signatures was also examined. The elemental, fatty acid and isotopic composition of their faecal pellets were compared to that of their food, providing insights into AEs and digestive isotopic discrimination. 4. Gut AEs typically followed the sequence: PUFA > nitrogen > carbon, although low AE for DHA was a notable exception. Starvation-induced losses of carbon, nitrogen, EPA and DHA demonstrate that homeostatic organisms must ingest all of these substrates in substantial quantity to achieve positive net growth. 5. Egested material was significantly depleted in 13C and 15N relative to the ingested food. We attribute this to isotopic discrimination at the macromolecular level, indicating that food quality contributes to the isotopic signature of a consumer organism. Values of δ15N in the copepods’ tissues did not increase during starvation, despite significant losses of bulk nitrogen. This supports the suggestion that dissimilatory protein pathways in marine crustaceans are non-discriminating. 6. The significant basal turnover rates and variable AEs for essential PUFAs and nitrogen presented herein demonstrate that organisms cannot be assumed to utilize all nutritious substrates with the same, high efficiency, even when scarce in the diet. Our data highlight the need for a more detailed understanding of organismal physiology before isotopic and stoichiometric models can be meaningfully constructed and parameterized.

A graph is 2K"2-partitionable if its vertex set can be partitioned into four nonempty parts A, B, C, D such that each vertex of A is adjacent to each vertex of B, and each vertex of C is adjacent to each vertex of D. Determining whether an arbitrary graph is 2K"2-partitionable is the only vertex-set partition problem into four nonempty parts according to external constraints whose computational complexity is open. We establish that the 2K"2-partition problem parameterized by minimum degree is fixed-parameter tractable. We also show that for C"4-free graphs, circular-arc graphs, spiders, P"4-sparse graphs, and bipartite graphs the 2K"2-partition problem can be solved in polynomial time.

Bottle incubations were conducted to examine how exposure to seawater containing 8000 ppm carbon dioxide (CO2; pH 6.95) influenced the growth and reproduction of the keystone copepod Calanus finmarchicus. The chosen concentration of CO2 is expected to occur over 100s of cubic kilometres of seawater as a result of marine CO2 storage/disposal, and is also representative of the predicted ‘worst-case’ atmospheric CO2 scenario in the year 2300. Growth (egg production and biomass loss) in adult female copepods was not affected by the simulated ocean acidification. In contrast, a maximum of only 4% of the eggs successfully yielded nauplii after 72 h in the experimental treatment. Our results demonstrate that environmental risk assessments for marine CO2 storage/disposal must look beyond adult mortality as an endpoint. Furthermore, if CO2 is to be disposed of in the deep sea, the location and timing of such activities must take into consideration the overwintering populations of C. finmarchicus.

How productive is Internet marketing? Results of a nationwide survey show that only 52 percent of Internet marketing users have specific, measurable objectives with the most popular being mechanical or communication measures. Even though multiple criteria are common, fewer than one in six firms use financial productivity measures.

© 2014 European College of Sport Science. The aim of this study was to investigate if the effects of changes in physiological arousal on timing performance can be accurately predicted by the catastrophe model. Eighteen young adults (8 males, 10 females) volunteered to participate in the study following ethical approval. After familiarisation, coincidence anticipation was measured using the Bassin Anticipation Timer under four incremental exercise conditions: Increasing exercise intensity and low cognitive anxiety, increasing exercise intensity and high cognitive anxiety, decreasing exercise intensity and low cognitive anxiety and decreasing exercise intensity and high cognitive anxiety. Incremental exercise was performed on a treadmill at intensities of 30%, 50%, 70% and 90% heart rate reserve (HRR) respectively. Ratings of cognitive anxiety were taken at each intensity using the Mental Readiness Form 3 (MRF3) followed by performance of coincidence anticipation trials at speeds of 3 and 8 mph. Results indicated significant condition × intensity interactions for absolute error (AE; p =.0001) and MRF cognitive anxiety intensity scores (p =.05). Post hoc analysis indicated that there were no statistically significant differences in AE across exercise intensities in low–cognitive anxiety conditions. In high–cognitive anxiety conditions, timing performance AE was significantly poorer and cognitive anxiety higher at 90% HRR, compared to the other exercise intensities. There was no difference in timing responses at 90% HRR during competitive trials, irrespective of whether exercise intensity was increasing or decreasing. This study suggests that anticipation timing performance is negatively affected when physiological arousal and cognitive anxiety are high.

Photosynthesis in the surface ocean produces approximately 100 gigatonnes of organic carbon per year, of which 5 to 15 per cent is exported to the deep ocean1, 2. The rate at which the sinking carbon is converted into carbon dioxide by heterotrophic organisms at depth is important in controlling oceanic carbon storage3. It remains uncertain, however, to what extent surface ocean carbon supply meets the demand of water-column biota; the discrepancy between known carbon sources and sinks is as much as two orders of magnitude4, 5, 6, 7, 8. Here we present field measurements, respiration rate estimates and a steady-state model that allow us to balance carbon sources and sinks to within observational uncertainties at the Porcupine Abyssal Plain site in the eastern North Atlantic Ocean. We find that prokaryotes are responsible for 70 to 92 per cent of the estimated remineralization in the twilight zone (depths of 50 to 1,000 metres) despite the fact that much of the organic carbon is exported in the form of large, fast-sinking particles accessible to larger zooplankton. We suggest that this occurs because zooplankton fragment and ingest half of the fast-sinking particles, of which more than 30 per cent may be released as suspended and slowly sinking matter, stimulating the deep-ocean microbial loop. The synergy between microbes and zooplankton in the twilight zone is important to our understanding of the processes controlling the oceanic carbon sink.

The performance of a new mesozooplankton sampler, the U-Tow, was compared to that of the traditional WP2 net. The U-Tow significantly underestimated species abundance, but gave a very good representation of species composition and community size structure. WP2 net samples could be used to calibrate the U-Tow, allowing absolute abundance to be determined. It is recommended that the U-Tow, in its current configuration, be used in conjunction with WP2 net samples to give measures of abundance, or as a tool to identify areas of change in plankton communities.

We consider the problem of deciding whether a k-colored graph can be completed to have a given property. We establish that, when k is not fixed, the completion problem for circular-arc graphs, even unit or proper circular-arc graphs, is NP-complete. When k is fixed, in the case of completion to circular-arc graphs and Helly circular-arc graphs, we fully classify the complexities of the problems. We also show that deciding whether a 3-colored graph can be completed to be strongly chordal can be done in O(n 2) time. As a corollary of our results, the sandwich problem for Helly circular-arc graphs is NP-complete.

The impact of problem-based learning (PBL) in improving academic achievement compared with other forms of teaching is equivocal. This paper argues that poor tutorial preparation and vague reporting of the brainstorming stage of PBL are major contributing factors. To address these issues this study incorporated a scaffolding mechanism into the pre-tutorial brainstorming stage of the PBL process based on de Bono’s (1995) Six Thinking Hats. Results confirmed that pre-tutorial preparation, when measured by attendance and academic achievement, increased across all levels of the undergraduate program for the PBL groups that used scaffolding, when compared to PBL groups without scaffolding and lecture-based delivery groups. This study supports the inclusion of scaffolding during the brainstorming stage of PBL.

We used a questionnaire to identify university students with self-reported difficulties in reading acquisition during elementary school (self-report; n=31). The performance of the self-report group on standardized measures of word and non-word reading and fluency, passage comprehension and reading rate, and phonological awareness was compared to that of two other groups of university students: one with a recent diagnosis (diagnosed; n=20) and one with no self-reported reading acquisition problems (comparison group; n=33). The comparison group outperformed both groups with a history of reading difficulties (self-report and diagnosed) on almost all measures. The self-report and diagnosed groups performed similarly on most tasks, with the exception of untimed reading comprehension (better performance for diagnosed) and reading rate (better performance for self-report). The two recruitment methods likely sample from the same underlying population but identify individuals with different adaptive strategies.

The major morbidity of colorectal anastomoses is leaks. The concept of staple-line reinforcement is a growing area of interest. In this study, we evaluated the feasibility and effect of utilizing AlloDerm to bolster end-to-end stapled rectal anastomoses in a porcine model.A total of 30 female 45-kg domestic pigs were studied, and each served as its own control by creating a bolstered and unbolstered anastomosis in each animal. All anastomoses were created with a 29-mm end-to-end stapling device. Bolstered anastomoses were randomized to proximal and distal positions along the rectum, and each rectorectal anastomosis was separated by an average of 10 cm. In 20 pigs, an unmeshed bolster of a 0.5-0.7-mm thickness was used. The remaining 10 pigs had a 1:1 meshed bolster that was 0.34-0.51 mm thick. The animals were survived for 14 days. Barium enemas were then performed and the two anastomotic sites harvested, and each anastomosis underwent burst testing. The internal diameter of each anastomosis was measured and a biochemical analysis was performed for matrix metalloproteinase (MMP), elastin and collagen content.The unmeshed bolstered anastomoses burst fewer times than the unbolstered anastomoses (P=0.004) and had higher burst pressures (P=0.023), though their anastomotic circumferences were smaller (P=0.007). Meshed bolsters offered no strength advantage to anastomoses and were significantly (P=0.009) smaller than unbolstered anastomoses in the same animal. No difference in elastin, collagen, or MMP content was observed between bolstered and unbolstered groups. No animals had clinical or radiographic leaks.The routine use of unmeshed and 1:1 meshed AlloDerm bolsters is safe and does not appear to inhibit healing in elective colorectal surgery on healthy subjects. AlloDerm may have a role as a tissue bolster in select patients who are more prone to develop anastomotic leaks.

We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton time-series stations has enabled us to collect and synthesise seasonal and multi-annual data on abundance, body size, fecundity, hatching success and vertical distribution of C. helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C. finmarchicus is known to over-winter at depth, whereas the life-cycle of C. helgolandicus is less well understood. Overwintering populations of C. helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deep-water populations at depths as great as 4200 m. The biogeographical distribution of C. helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6% to 93%. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C. helgolandicus is generally found in 9–20 C water, with maximum abundances from 13–17 C. In contrast, C. finmarchicus is found in cooler water between 0 and 15 C, with peak abundances from 0 to 9 C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species. Versión del editor