78 research outputs found

    The principle of biological attraction, demonstrated by the bio-continuum theory of zooplankton patch dynamics

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    A theory of zooplankton and micronekton patch dynamics is developed that expressly includes animal behavior. This represents a departure from traditional models of patch dynamics, which generally treat animals as Lagrangian particles whose distributions are determined solely by processes of advection and diffusion. The “bio-continuum” theory is based on principles of statistical mechanics, and describes animal aggregations in terms of mean motion, random motion, random kinetic energy, distribution and abundance. The forces on an animal aggregation act both upon the aggregation as a whole (external forces) or between individuals (internal forces). We demonstrate here that the internal forces which serve to maintain autocoherence are, in essence, a force of biological attraction that can be quantified in Newtons. A coefficient of biological attraction is defined, and its magnitude evaluated in aggregations of Antarctic euphausiids (Euphausia superba). We hypothesize that the coefficient of biological attraction may be constant for all organisms in the sea. A method for measuring all key variables with acoustic Doppler technology is presented, with specific attention to application of the Acoustic Doppler Current Profiler (ADCP). We conclude that bio-continuum theory, coupled with acoustic Doppler observations, provides a practical approach for studying animal aggregation dynamics in the sea

    Mesoscale distribution of zooplankton in the California Current in late spring, observed by Optical Plankton Counter

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    A survey of zooplankton in the upper 300 m of the central California Current, from the coastal shelf to 128W and between 36.5N and 39.5N, was conducted in early June 1993 using an Optical Plankton Counter (OPC) as part of an interdisciplinary study of mesoscale ocean circulation and biological dynamics. The OPC was part of a multi-instrument package towed on an undulating vehicle (SeaSoar). Estimates of normalized size spectra and absolute abundance from OPC data compared favorably with measurements based on Bongo net catches. After processing, the standardized OPC data set provides a resolution of ≈7 km in the horizontal and 10 m in the vertical for 60 size categories of zooplankton ranging in estimated body weight from 3 ÎŒg C to 3000 ÎŒg C. Results reveal rich mesoscale variability in zooplankton distributions at scales of 30–60 km, with regions of enhanced biomass and abundance coinciding with the location of mesoscale eddies, both cyclonic and anticyclonic. The central jet of the California Current departed from the coastline near Cape Mendocino (39.5N), separating a region of generally greater zooplankton biomass near the coast from one of lower biomass to the west. The jet usually contained lower biomass than adjacent eddies. Total zooplankton biomass ranged from \u3c2 g C m−2 to \u3e20 g C m−2. The two mesoscale features containing the highest biomass, one 200 nm offshore of Cape Mendocino and another 100 nm west of Monterey Bay, were dominated by euphausiids

    Zooplankton grazers as transformers of ocean optics: A dynamic model

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    A model was developed, based on data collected in the Southern California Bight region, to assess the effect of zooplankton grazing on the attenuation of light due to suspended particles. Diel vertical distribution and grazing activity of the principal zooplankton grazers in the coastal waters of southern California were studied during mid-March, 1986. Calanus pacificus exhibited vertical migration, but Acartia spp. and Paracalanus spp. did not. All species had a diel feeding rhythm, whether or not they migrated; grazing activity, measured by the gut fluorescence method, increased at night. Model parameters are temperature, particle doubling rate, particle size-frequency distribution, zooplankton grazing efficiency and zooplankton size-frequency distribution. With parameters at their standard values, the diffuse attenuation coefficient, Kp, remains approximately constant, decreasing by only 3.5% in one 24-h cycle. The model is most sensitive to changes in temperature and, secondly, to changes in the abundance of grazers. Without grazers, and at the reference value for particle doubling rate, Kp is expected to increase by 8.2% d−1. At the upper limit of zooplankton abundance grazing produces a decrease in Kp of 63.5% d−1; at the upper limit of particle growth rate, Kp increases by ≄50% d−1. We conclude that macrozooplankton can have a major effect on the optical characteristics of sea water

    Algal food and fuel coproduction can mitigate greenhouse gas emissions while improving land and water-use efficiency

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    The goals of ensuring energy, water, food, and climate security can often conflict.Microalgae (algae) are being pursued as a feedstockfor both food and fuels—primarily due to algae’s high areal yield and ability to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation requires significant energy inputs that may limit potential emission reductions.We examine the tradeoffs associated with producing fuel andfood from algae at the energy–food–water–climate nexus.We use the GCAM integrated assessment model to demonstrate that algalfood production can promote reductions in land-use change emissions through the offset of conventional agriculture. However,fuel production, either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt– water algae for food products may lead to substantial freshwater savings; but, nutrients for algae cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land demand of food production, while simultaneously enhancingfood and energy security, algae can further enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and storage. Our results demonstrate that large-scale algae research and commercialization efforts should focus on developing both food and energy products to achieve environmental goals.https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114006/metaPublished versio

    Marine Microalgae: Climate, Energy, and Food Security From the Sea

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    Climate, energy, and food security are three of the greatest challenges society faces this century. Solutions for mitigating the effects of climate change often conflict with solutions for ensuring society’s future energy and food requirements. For example, BioEnergy with Carbon Capture and Storage (BECCS) has been proposed as an important method for achieving negative CO2 emissions later this century while simultaneously producing renewable energy on a global scale. However, BECCS has many negative environmental consequences for land, nutrient, and water use as well as biodiversity and food production. In contrast, large-scale industrial cultivation of marine microalgae can provide society with a more environmentally favorable approach for meeting the climate goals agreed to at the 2015 Paris Climate Conference, producing the liquid hydrocarbon fuels required by the global transportation sector, and supplying much of the protein necessary to feed a global population approaching 10 billion people

    Long-Term Neurodevelopmental Outcome of Monochorionic and Matched Dichorionic Twins

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    Contains fulltext : 79941.pdf (publisher's version ) (Open Access)BACKGROUND: Monochorionic (MC) twins are at increased risk for perinatal mortality and serious morbidity due to the presence of placental vascular anastomoses. Cerebral injury can be secondary to haemodynamic and hematological disorders during pregnancy (especially twin-to-twin transfusion syndrome (TTTS) or intrauterine co-twin death) or from postnatal injury associated with prematurity and low birth weight, common complications in twin pregnancies. We investigated neurodevelopmental outcome in MC and dichorionic (DC) twins at the age of two years. METHODS: This was a prospective cohort study. Cerebral palsy (CP) was studied in 182 MC infants and 189 DC infants matched for weight and age at delivery, gender, ethnicity of the mother and study center. After losses to follow-up, 282 of the 366 infants without CP were available to be tested with the Griffiths Mental Developmental Scales at 22 months corrected age, all born between January 2005 and January 2006 in nine perinatal centers in The Netherlands. Due to phenotypic (un)alikeness in mono-or dizygosity, the principal investigator was not blinded to chorionic status; perinatal outcome, with exception of co-twin death, was not known to the examiner. FINDINGS: Four out of 182 MC infants had CP (2.2%) - two of the four CP-cases were due to complications specific to MC twin pregnancies (TTTS and co-twin death) and the other two cases of CP were the result of cystic PVL after preterm birth - compared to one sibling of a DC twin (0.5%; OR 4.2, 95% CI 0.5-38.2) of unknown origin. Follow-up rate of neurodevelopmental outcome by Griffith's test was 76%. The majority of 2-year-old twins had normal developmental status. There were no significant differences between MC and DC twins. One MC infant (0.7%) had a developmental delay compared to 6 DC infants (4.2%; OR 0.2, 95% 0.0-1.4). Birth weight discordancy did not influence long-term outcome, though the smaller twin had slightly lower developmental scores than its larger co-twin. CONCLUSIONS: There were no significant differences in occurrence of cerebral palsy as well as neurodevelopmental outcome between MC and DC twins. Outcome of MC twins seems favourable in the absence of TTTS or co-twin death

    Why do you drink caffeine? The development of the Motives for Caffeine Consumption Questionnaire (MCCQ) and its relationship with gender, age and the types of caffeinated beverages

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    Caffeine is the most popular psychoactive substance that is consumed worldwide. As motives influence behavior, investigation of the motivational background of caffeine consumption should help provide a better understanding of the popularity of caffeinated products. The present study aimed (i) to explore and operationalize the motives of caffeine consumption and (ii) to reveal possible differences in the motives regarding gender, age and the type of caffeinated products consumed. Motives for caffeine consumption were collected from regular caffeine consumers (N = 26) and were informed by a review of the relevant literature. Following this, a cross-sectional study was conducted on a convenience sample of Hungarian university students and working adults (N = 598). The participants completed the Motives for Caffeine Consumption Questionnaire and the Caffeine Consumption Questionnaire. Six motivational factors were identified: Alertness, Habit, Mood, Social, Taste and Symptom Management. Women had higher scores on Habit, Social, Taste and Symptom Management. Younger participants had higher scores on Alertness than the older group, and the older group had higher scores on Habit and Symptom Management. Five types of caffeine users were identified. Those who consumed (i) coffee, (ii) tea, (iii) energy drinks, (iv) coffee and tea and (v) mixed drinks. Several differences between the five groups were revealed across all motives except for Taste. The present study developed a robust psychometric instrument for assessing caffeine consumption motives. The factors varied in importance in relation to gender, age and caffeine consumption habits

    Real-world experience of nintedanib for progressive fibrosing interstitial lung disease in the UK

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    Background Nintedanib slows progression of lung function decline in patients with progressive fibrosing (PF) interstitial lung disease (ILD) and was recommended for this indication within the United Kingdom (UK) National Health Service in Scotland in June 2021 and in England, Wales and Northern Ireland in November 2021. To date, there has been no national evaluation of the use of nintedanib for PF-ILD in a real-world setting.Methods 26 UK centres were invited to take part in a national service evaluation between 17 November 2021 and 30 September 2022. Summary data regarding underlying diagnosis, pulmonary function tests, diagnostic criteria, radiological appearance, concurrent immunosuppressive therapy and drug tolerability were collected via electronic survey.Results 24 UK prescribing centres responded to the service evaluation invitation. Between 17 November 2021 and 30 September 2022, 1120 patients received a multidisciplinary team recommendation to commence nintedanib for PF-ILD. The most common underlying diagnoses were hypersensitivity pneumonitis (298 out of 1120, 26.6%), connective tissue disease associated ILD (197 out of 1120, 17.6%), rheumatoid arthritis associated ILD (180 out of 1120, 16.0%), idiopathic nonspecific interstitial pneumonia (125 out of 1120, 11.1%) and unclassifiable ILD (100 out of 1120, 8.9%). Of these, 54.4% (609 out of 1120) were receiving concomitant corticosteroids, 355 (31.7%) out of 1120 were receiving concomitant mycophenolate mofetil and 340 (30.3%) out of 1120 were receiving another immunosuppressive/modulatory therapy. Radiological progression of ILD combined with worsening respiratory symptoms was the most common reason for the diagnosis of PF-ILD.Conclusion We have demonstrated the use of nintedanib for the treatment of PF-ILD across a broad range of underlying conditions. Nintedanib is frequently co-prescribed alongside immunosuppressive and immunomodulatory therapy. The use of nintedanib for the treatment of PF-ILD has demonstrated acceptable tolerability in a real-world setting

    Behavioral Corporate Finance: An Updated Survey

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