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Harmful algal blooms (HAB) are natural environmental occurrences that can disrupt ecosystem function that supports fisheries and aquaculture, as well as rendering harvested seafood, especially shellfish, unsafe for consumption by humans or wildlife species. Many dinoflagellates that cause HAB have a life cycle with a sexually produced resting stage called the resting cyst. The resting cyst enables the species to persist in an area where conditions for growth vary seasonally. These species often are found as vegetative stages only during a short period of the year. Most of the time is spent dormant or quiescent as thick-walled resting cysts with very low metabolic activity. By summarizing findings from an iterative series of research projects investigating different parts of the sexual life cycle, a more complete picture of the role of the sexual stages emerges, illuminating the consequences of life cycle within the environmental context. Gametes, the sexual stages, are formed at the end of the growing season in response to environmental signals which remain largely unknown. Gametes have lower cell-specific density and different swimming behavior compared to vegetative cells. Specifically, vegetative cells perform daily vertical migrations; whereas, gametes accumulate in patterns influenced by lower cell-specific density, changed swimming behavior, and attraction to each other. The patterns and patches of accumulated gametes (sexually induced cells) aggregate into larger and larger patterns. Together with large-scale hydrographic water movements, such as upwelling, water stratification, and fronts, cells originating from a low vegetative cell density background distribution assemble and become concentrated within a constricted space, thus forming a dense "bloom." This process is distinctly different from the paradigm of blooms resulting from simple, vegetative cell divisions. Undisturbed blooms of cyst-producing dinoflagellate gametes end with gamete fusion into diploid zygotes that transform into resting cysts. The resting cysts sink according to shape and cell-specific density into the silt fraction of the sediment. Cyst preservation depends upon the oxygenation level of the sediment and the presence of fauna. Hypoxic/anoxic conditions lower cyst mortality from benthic grazers. The reestablishment of motile, vegetative cells occurs under seasonally favorable conditions, and successful population growth depends upon environmental conditions, such as weather and nutrient availability. Factors that increase HAB risks of resting cyst-producing dinoflagellates are eutrophication leading to high cell numbers and high cyst preservation in hypoxic benthic zones. Hydrographic factors causing increased cell accumulation also are important, and intensified water stratification can amplify encystment success. These insights underscore mechanisms by which climate change is affecting HAB ecology and subsequent effects upon marine and coastal fisheries and aquaculture. [ABSTRACT FROM AUTHOR]

Dinoflagellates constitute one of the most important groups of primary producers and micro-zooplankton on earth, common in both marine and freshwater environments. Despite their prominent position among phytoplankton, they are difficult to grow into dense cultures in the laboratory. This discrepancy between field and laboratory indicates serious limitations caused by the laboratory culturing conditions. A difficult to study but important factor is the constraints of enclosure in a limited volume of water. We conducted an experiment wherein the dinoflagellate Scrippsiella lachrymosa was grown in "flow cells" – 100 cm3 cylindrical cages constructed from plankton net, inserted in larger volumes of growth medium, allowing an exchange of medium without dilution of the culture. Cell numbers far exceeding the normal for culturing of this species and dinoflagellates in general were attained, even though the experiment was terminated before cultures reached stationary phase. A cell number ten times higher than under regular batch culturing was achieved (up to 340,000 cells mL−1). Pattern formation was distinct in cultures when cells were plentiful and water movements caused cell accumulation, not dispersion. High cell density concurrent with access to new growth medium promoted induction of the sexual cell cycle. The results indicate serious limitations to growth set by enclosure in a limited water volume in laboratory experiments; thus, maximum growth rates of dinoflagellates in favourable field conditions may be vastly underestimated. Cell accumulation behavior of dinoflagellates during the sexual life cycle may together with physical transport by larger forces in nature explain sudden bloom occurrences. [ABSTRACT FROM AUTHOR]

This quantitative dinoflagellate cyst study reveals an enormous difference in survival rates in oxygenated versus anoxic sediments. Replicate samples of concentrated natural dinoflagellate cysts with the same initial species composition (1.4 × 104 resting cysts·cm−3 sediment, 61% filled with live-appearing contents) were placed in bags of 20 µm plankton screen. Replicate bags containing 10.0 cm−3 concentrated cyst samples were placed on the seafloor in different environments in Long Island Sound, USA (anoxic and oxygenated), as well as refrigerated in test tubes in the laboratory. Three sets of 15 bags were placed in each environment. Once every year for four consecutive years, three bags were recovered from each set, and the contents were analyzed by cyst counting and germination experiments. An enormous difference in preservation potential between samples in oxygenated versus anoxic environments was revealed. The number of dinoflagellate cysts decreased abruptly within the first year in the oxygen-rich environment; living cysts became very rare (only 5% remained) and also empty walls of cysts disappeared (20% of total cysts remained). In anoxic sediment samples, living cysts also decreased significantly with time, but less quickly. After 1 year, 35% of the living cysts in the anoxic environment and 70% of the living cysts refrigerated in test tubes remained intact. After 4 years, 21% of the cysts with contents in the anoxic environment remained, and 31% in test tubes. The empty cyst walls remained intact for a longer time under anoxic conditions, especially of species known to fossilize well. Germination experiments showed that cysts with live-appearing contents were likely alive, because species with identifiable live-appearing cysts were also identified as vegetative cells in corresponding slurry cultures. The cyst assemblage was dominated by Protoperidinaceae, Dipolopsalidaceae, and Gonyaulacaceae. Of special interest is the ichthyotoxic Margalefodinium polykrikoides, the bloom-forming Peridinium quinquecorne, which has an undescribed resting cyst, and a previously undescribed Krypoperidinium species. The results show greater preservation of dinoflagellate cysts in "dead-zone sea bottoms" and may also provide an answer to the question of the absence of cyst beds in an area despite observed sedimentation of dense blooms. [ABSTRACT FROM AUTHOR]

One previously unstudied aspect of differences between sexual and asexual life stages in large‐scale transport and accumulation is density (mass per unit volume) of cells in each life stage. The specific density was determined for Scrippsiella lachrymosa cells in medium with and without nitrogen (N) enrichment through density‐gradient centrifugation. Growth medium without N addition is often called "encystment medium" when used for the purpose of resting cyst formation in cyst‐forming dinoflagellates; mating gametes are usually seen after 2–3 days. Significant differences in specific density were found after 2 days in encystment medium simultaneously with the observation of typical gamete swimming behavior and mating. The specific density of cells in encystment medium was 1.06 g · cm−3; whereas, the specific density of cells in growth medium was 1.11 g · cm−3. Cells in encystment medium were found to have significantly increased lipid content, reduced chlorophyll content, and reduced internal complexity. The findings may explain differential transport of less dense and chemotactically aggregating gametes into surface blooms in contrast to denser vegetative cells that perform daily vertical migration and do not aggregate. Passive accumulation of non‐migrating gametes into layers in stagnant water also can be explained, as well as sinking of zygotes when the storage of highly dense starch increases. Resting cysts had a density of over 1.14 g · cm−3 and would sink to become part of the silt fraction of the sediment. We suggest that differences in behavior and buoyancy between sexual and asexual life stages cause differences in cell accumulation, and therefore large‐scale, environmental transport could be directly dependent upon life‐cycle transitions. [ABSTRACT FROM AUTHOR]

The growth of continuously generated, large-scale datasets, and new analytics to handle them, has created expectations, in some quarters, that new insights can be generated that will help us address the biggest challenges that face us as a species and therefore can shape future societal outcomes. It is hoped that these new technologies will lead not just to new discoveries but also to new questions and thinking that will deliver significant scientific advances. Perhaps there will be some genuine scientific advances but since many of the challenges that face us reside in the human world and depend upon how humans behave, we need to turn to the humanities and the social sciences as well as the natural sciences and look at the role Big Data could play there in adding to, or shaping, our future. And here, what concerns us is not just the assumptions guiding the new analytic techniques for data mining, data merging, linking and analysis, born out of smarter AI algorithms, it is a more fundamental issue about the constraints and limitations of the kind of data inputs and outputs being appealed to in Big Data systems and whether they are well served to provide an understanding of the human world. [ABSTRACT FROM AUTHOR]

Background: Although most Scotch whisky is blended from different casks, a firm distinction exists in the minds of consumers and in the marketing of Scotch between single malts and blended whiskies. Consumers are offered cultural, geographical and production reasons to treat Scotch whiskies as falling into the categories of blends and single malts. There are differences in the composition, method of distillation and origin of the two kinds of bottled spirits. But does this category distinction correspond to a perceptual difference detectable by whisky drinkers? Do experts and novices show differences in their perceptual sensitivities to the distinction between blends and single malts? To test the sensory basis of this distinction, we conducted a series of blind tasting experiments in three countries with different levels of familiarity with the blends versus single malts distinction (the UK, the USA and France). In each country, expert and novice participants had to perform a free sorting task on nine whiskies (four blends, four single malts, one single grain, plus one repeat) first by olfaction, then by tasting. Results: Overall, no reliable perceptual distinction was revealed in the tasting condition between blends and single malts by experts or novices when asked to group whiskies according to their similarities and differences. There was nonetheless a clear effect of expertise, with experts showing a more reliable classification of the repeat sample. French experts came closest to a making a distinction between blends and single malts in the olfactory condition, which might be explained by a lack of familiarity with blends. Interestingly, the similarity between the blends and some of their ingredient single malts explained more of participants' groupings than the dichotomy between blends and single malts. Conclusions: The firmly established making and marketing distinction between blends and single malts corresponds to no broad perceptually salient difference for whisky tasters, whether experts or novices. The present study indicates that successfully blended whiskies have their own distinctive and recognizable profiles, taking their place in a common similarity space, with groupings that can reflect their component parts. [ABSTRACT FROM AUTHOR]

Various life cycle stages of cyst-producing dinoflagellates often appear differently colored under the microscope; gametes appear paler while zygotes are darker in comparison to vegetative cells. To compare physiological and photochemical competency, the pigment composition of discrete life cycle stages was determined for the common resting cyst-producing dinoflagellate Scrippsiella lachrymosa. Vegetative cells had the highest cellular pigment content (25.2 ± 0.5 pg · cell−1), whereas gamete pigment content was 22% lower. The pigment content of zygotes was 82% lower than vegetative cells, even though they appeared darker under the microscope. Zygotes of S. lachrymosa contained significantly higher cellular concentrations of β-carotene (0.65 ± 0.15 pg · cell−1) than all other life stages. Photoprotective pigments and the de-epoxidation ratio of xanthophylls-cycle pigments in S. lachrymosa were significantly elevated in zygotes and cysts compared to other stages. This suggests a role for accessory pigments in combating intracellular oxidative stress during sexual reproduction or encystment. Resting cysts contained some pigments even though chloroplasts were not visible, suggesting that the brightly colored accumulation body contained photosynthetic pigments. The differences in pigmentation between life stages have implications for interpretation of pigment data from field samples when sampled during dinoflagellate blooms. [ABSTRACT FROM AUTHOR]

The article discusses the role of metacognition to the individual. The author talks about the ide of psychologist Joelle Proust about the role of metacognition in constituting oneself as a person. Also tackled is the recommendation of Proust about the understanding of the notion, metacognition is an indispensible part of the toolkit for the human mind.

This paper discusses in detail the calculation of internuclear distances of heteronuclear single bond covalent molecules in the gaseous state. It reviews briefly the effect of electronegativity in covalent bond length. A set of single bond covalent radii and electronegativity values are proposed. Covalent bond lengths calculated by an adapted form of a simple expression (which calculated internuclear separation of different Group 1 and Group 2 crystalline salts to a remarkable degree of accuracy) show very good agreement with observed values. A small number of bond lengths with double bonds as well as bond lengths in the crystalline state are calculated using the same expression and when compared with observed values also give good agreement. This work shows that covalent radii are not additive and that radii in the crystalline state are different from those in the gaseous state. The results also show that electronegativity is a major influence on covalent bond lengths and the set of electronegativity scale and covalent radii proposed in this work can be used to calculate covalent bond lengths in different environments that have not yet been experimentally measured. [ABSTRACT FROM AUTHOR]

Highlights: [•] Karenia brevis sexual life-cycle is heterothallic with isogamous gametes. [•] The late zygote resembles the “possible cyst” found earlier but does not form a true resting cyst. [•] Temperature induced morphological changes and differences between life cycle stages allow cryptic occurrence. [Copyright &y& Elsevier]

Abstract: Different life stages of Alexandrium fundyense have different swimming behavior; gametes often are said to “swarm” or “dance” before mating. This behavior was studied, and quantitative measures of these motility patterns in two-dimensions were generated using motion-analysis software applied to video records of individual-cell movements. Behavior, swimming patterns, and growth were studied in two strains of A. fundyense and compared in encystment medium and growth medium. Vegetative cells swam straight, rotating around the apical axis until they hit something and then swam straight in a different direction. Gamete swimming behavior was slower and characterized by frequent direction changes and circular motion. Gametes contacted other cells frequently (>5cellcontactsmin−1 cell−1). Zygotes swam slowly when newly formed and later became nearly immobile; these cells continued to contact other cells and also surfaces. The results are in accordance with field observations of long swimming distances for vegetative cells, accumulation in thin layers of gametes, and sinking of developing resting cysts attached to marine snow for zygotes. [Copyright &y& Elsevier]

Abstract: Different life stages of two mating-compatible clones of the paralytic shellfish toxin (PST)-producing dinoflagellate Alexandrium fundyense Balech were separated using a combination of techniques; culturing and sampling methods were used to separate vegetative cells and gametes, and sorting flow cytometry was used to separate zygotes. PST profiles were significantly different between life stages; the two gonyautoxins GTX1 and 2 were present in vegetative and senescent cells, but disappeared from gametes and zygotes. Toxin-profile changes were shown to occur very quickly in both strains when pellicle cyst formation was induced by shaking (four minutes) followed by rinsing on a screen. These pellicle cysts produced from exponentially-growing, vegetative cells lost GTX1 and 2 completely. Rapid toxin epimerization of GTX1 to GTX4 and GTX2 to GTX3 is one possible explanation, although the biological advantage of this remains unclear. Another possible explanation is that during the mating phase of a bloom or when cells are disturbed, GTX1 and GTX2 are released into the surrounding water. It may be advantageous for a dinoflagellate bloom to be surrounded by free toxins in the water. [Copyright &y& Elsevier]

Is relativism about truth ever a coherent doctrine? Some people have argued that an answer to this question depends on whether there can be cases of genuine disagreement where those who disagree hold conflicting beliefs towards the same proposition and yet are each entitled to say that what they believe is true. These have been called cases of faultless disagreement and are often explored by considering the case of disagreements about taste. However, this is not the right way to formulate the relativist's doctrine, and the discussions of taste are often based on a faulty view about the nature of taste and about the workings of predicates of taste. I examine the taste case in more detail and consider the prospects for a genuine form of truth relativism. [ABSTRACT FROM AUTHOR]

The article presents a study on the ionization energies of lanthanide. It mentions that the knowledge of ionization energies is essential in understanding the chemistry of elements. In addition, the determination of the stability of inorganic compounds using Born-Haber cycle calculations is an important application of ionization energies. Meanwhile, lanthanides were initially used as catalysts in petroleum cracking and as phosphors in fluorescent surfaces. However, erbium and a few other lanthanides were found to be necessary in optical components of communication networks.

This paper presents a new methodology for incorporating origin and destination (O&D) network effects into the fleet assignment process. The methodology uses a decomposition strategy to combine a modified version of a leg-based fleet assignment model (Leg-FAM) with the network flow aspects of probabilistic O&D yield management. By decomposing the problem, the nonlinear aspects of the O&D market effects and passenger flow are isolated in O&D yield management and incorporated in FAM using linear approximations to the total network revenue function. To illustrate this methodology and its economic benefits, an example consisting of 10 cities, 48 flight legs, and 534 O&D market classes is presented and compared to the results found using two commonly used Leg-FAM formulations. To benchmark the benefits of using an O&D approach to fleet assignment, we present two case studies comparing the Leg-FAM and O&D FAM approaches using actual airline schedules with more than 4,000 daily operations. For these benchmarks, we present the results of a general fleet assignment process in which all the scheduled flights must be assigned an aircraft type and a schedule reduction run in which nonprofitable flights can be cancelled. The methodology presented in this paper is ideally suited for demand-driven dispatch (D3) scenarios, where near-term fleeting changes are made to better match O&D passenger demand to available aircraft capacity. To illustrate the use of the O&D FAM methodology to facilitate near-term refleeting process, we present results from implementing a D3 process using O&D FAM at AMR's American Eagle Airlines. [ABSTRACT FROM AUTHOR]

Abstract: For some species of cyst-producing dinoflagellates, the sexual life cycle is well studied in laboratory cultures. Dinoflagellate blooms in stratified waters, vertical migration of vegetative cells, and the accumulation of populations within thin layers are well-documented phenomena in nature. We propose a conceptual model that places these phenomena in a functional, ecological context: vegetative cells of a dinoflagellate population display vertical migration, but at the end of the bloom, environmental or internal cues shift the cell cycle to gamete formation. Then the vertical migrations cease, and cells accumulate in a layer at the pycnocline where gametes fuse to form zygotes, which then sink to the sediment as resting cysts. We support this conceptual model with experimental and environmental evidence. [Copyright &y& Elsevier]

Abstract: In laboratory experiments, oysters (Crassostrea virginica) were fed Alexandrium fundyense (strain CB501) vegetative cells or resting cysts (from strains CB501 and GMT25) produced from laboratory cultures. The toxicity per cyst was 1.7pgSTXequiv/cyst and for vegetative cells 3.9pgSTXequiv/cell. The toxic, resting cysts and vegetative cells were removed from suspension in the experimental containers within about 4h. Oysters fed toxic vegetative cells digested 72% of cells ingested, and 28% survived gut passage by forming temporary cysts. Toxin levels of oysters fed vegetative cells averaged 27μgSTXequiv/100g meat. Resting cysts added to the experimental containers adhered to the walls so that only 40% of the cysts added were available to the oysters during the experiment. Of the cysts that were ingested, approximately 59% were digested, and oysters accumulated toxins (an average of 1.2μgSTXequiv/100g meat), showing that consumption of resting cysts can cause toxicity in oysters. Direct consumption of resting cysts, thus, may explain shellfish toxicity in areas without known blooms, but with toxic resting cysts in the sediment. These results suggest a possible role of toxic cysts in mediating time-lags between surface blooms and appearance of toxicity in benthic grazers, and the possible role of benthic grazers in controlling seed populations, except in anoxic areas, which can serve as cyst “refuges” from grazing mortality. [Copyright &y& Elsevier]

Describes some less familiar aspects of ionization energies of atoms and atomic ions. Difference between ionization potential and ionization energy; Atomic energy levels; Wave numbers; Periodicity; Ground state electronic configurations of transition-metal atoms and ions.

Comments on the proposal offered by Alex Barber in defusing the threat to the coherence of an objection. Enumeration of the claims on the problem created by tension; Fact on the generation of expectations; Views on the objectivity of linguistic facts.

Two mesocosm experiments were conducted to study the interaction of a commercial oyster-nursery system with the surrounding embayment, specifically, nutrient and plankton dynamics. The nursery was stocked with 80-200 L of oysters, sized 3-5 mm. Ambient water and the water passed through the oyster nursery were incubated in mesocosms, and nutrients and plankton were monitored over the course of 27-h incubations. The first experiment conducted in July 2009 captured a phytoplankton community dominated by Peridinium quinquecorne, a rare dinoflagellate not previously reported in the northeastern USA. Dissolved nitrogen compounds in all mesocosms were depleted within the first 6 h. The second experiment was conducted in September 2009, when a more typical and diverse phytoplankton community was present. Unlike the first experiment, Nitrate plus nitrite in the mesocosms was not depleted. Both experiments indicated little difference between the water passed through the oyster nursery and the ambient water in terms of subsequent nutrient and plankton dynamics, indicating little 'legacy effect' of the oyster nursery upon nutrients and plankton in this embayment. This conclusion was reached under the specific operating conditions typical for this nursery system, as chosen by the commercial partner in the study; changes in oyster stocking or flow rate are likely to change the results. [ABSTRACT FROM AUTHOR]

An examination of sterols of UTEX 2341, a small (ca. 2 μm), nonmotile unicellular marine alga identified as Cholerlla minutissima marina alga identified as Chlorella minutissma Fott et Novakova, yielded results inconsistent with any of 35 Chlorella strains analyzed previously. UTEX 2341 contained cholesterol as the principal sterol, with 24-methylenecholestrol, fucosterol, and isofucosterol also present; these are not dominant sterols in any other Chlorella species. Presence of eicosapentaenoic acid in UTEX 2341 also contrasted with fatty acids of Chlorella strains analyzed previously. Pigment analysis of UTEX 2341 revealed that it contained chlorophyll a, but not chloropyylls b or c; violaxanthin was the only major xanthophylls pigment. Both lipid and pigment compositions suggest that UTEX 2341 is not a member of the genus Chlorella but, rather, belongs in the Eustigmatophyceae; it may be Nannochloropsis sp. Cells with possible extracellular structures were present at an appreciable percentage of the stationary-phase population studied; centrifuging removed or collapsed these structures. The high cholestrol and polyunsalturated fatty acid contents of UTEX 2341 make it attractive as a potential aquaculture feed, provided it is, or can be made, digestive. [ABSTRACT FROM AUTHOR]