62 research outputs found
Possible Poecilogony Due to Discontinuous Multifactorial Inheritance in Some Mediterranean Species of Raphitoma (Mollusca, Conoidea, Raphitomidae)
At least 10 pairs of similar, most probably closely related, species of Raphitoma are often sampled in the same Mediterranean localities. In each pair, one member bears a planktotrophic protoconch and the other a lecithotrophic one. We propose that the phenomenon may be attributed to a simple gene that functions in conjunction with others and environmental factors to exhibit a discontinuous multifactorial inheritance leading to poecilogony. Below a threshold, the animals may produce fewer and larger germ cells, giving rise to fewer and larger eggs and large lecithotrophic embryos with large paucispiral protoconch I, while above that threshold, more and smaller germ cells leading to smaller eggs and to planktotrophic larvae with small protoconch I and large multispiral protoconch II. Preliminary measurements are in support of our hypothesis. Analysis of mitochondrial DNA markers as well as interbreeding experiments could bring an end to the existing confusion
Preliminary search for a νirus in Dacus oleae Gmel. populations in Northern Greece
Στην περίοδο από Ιούλιο έως Δεκέμβριο 1984 συλλέχΟησαν 4.5 g ακμαίων, 8.5 g υγιών προνυμφών και 0.45 g νεκρών προνυμφών του εντόμου Dacus oleae Gmel. από περιοχές της Βόρειας Ελλάδας, που χαρακτηρίζονταν από Βαριά προσβολή των ελαιοδένδρων από δάκο, στα οποία δεν εφαρμόστηκε χημική καταπολέμηση. Τα δείγματα εξετάσθηκαν για εγκλεισμένους και μη εγκλεισμένους ιούς με τη χρησιμοποίηση φυγοκεντρήσεων, οπτικού και ηλεκτρονικού μικροσκοπίου, ανάλυσης νουκλεϊ νικών οξέων KUI πειράματα μολυσματικότητας. Στα δείγματα των νεκρών προνυμφών, και σε αντίθεση με εκείνα των υγιών προνυμφών και των ακμαίων, εντοπίσθηκαν και απομονώθηκαν ιόμορφα σωμάτια. Τα σωμάτια αυτά είχαν διάμετρο περίπου 35 nm και μερικά ήταν άδεια, όπως φάνηκε από τη διείσδυση της χρωστικής κατά την αρνητική χρώση. Δεν κατέστη δυνατός ο παραπέρα χαρακτηρισμός των «ιοσωματίων» για το λόγο έλλειψης αρκετής ποσότητας δείγματος, ενώ προσπάθειες πολλαπλασιασμούτους σε προνύμφες του λεπιδόπτερου Galleria mellonella και σε καλλιέργειες κυττάρων Drosophila melanogastcr αποδείχθησαν ανεπιτυχείς. Αν και τα μικρά ιόμορφα σωμάτια ήταν το μοναδικό πιθανό παθογόνο αίτιο που αναγνωρίστηκε στις νεκρές προνύμφες, φαίνεται κάπως απίθανο να αποτελούν και το μοναδικό αίτιο του θανάτου για το λόγο του σχετικά μικρού αριθμού τους. Πάντως αν καταστεί δυνατό να πολλαπλασιασθούν οι «ιοί» αυτοί σε εκτροφές του δάκου της ελιάς ή σε καλλιέργειες κυττάρων ιστών του ίδιου εντόμου, ίσως να αποτελέσουν στο μέλλον ένα βιολογικό μέσο καταπολέμησης του.A large number of larvae of Dacus oleae were collected from infested olives in Northern Greece, and a small proportion of these were found to be dead. Adult flies were caught in McPhail traps at the same locations. The larvae and adults were fractionated by a series of steps designed to identify occluded and nonoccluded viruses. Virus-like particles were identified in small amounts only in the dead larvae
Enabling Efficient and General Subpopulation Analytics in Multidimensional Data Streams
Today’s large-scale services (e.g., video streaming platforms, data centers, sensor grids) need diverse real-time summary statistics across multiple subpopulations of multidimensional datasets. However, state-of-the-art frameworks do not offer general and accurate analytics in real time at reasonable costs. The root cause is the combinatorial explosion of data subpopulations and the diversity of summary statistics we need to monitor simultaneously. We present Hydra, an efficient framework for multidimensional analytics that presents a novel combination of using a “sketch of sketches” to avoid the overhead of monitoring exponentially-many subpopulations and universal sketching to ensure accurate estimates for multiple statistics. We build Hydra as an Apache Spark plugin and address practical system challenges to minimize overheads at scale. Across multiple real-world and synthetic multidimensional datasets, we show that Hydra can achieve robust error bounds and is an order of magnitude more efficient in terms of operational cost and memory footprint than existing frameworks (e.g., Spark, Druid) while ensuring interactive estimation times
Deep Learning for Energy Time-Series Analysis and Forecasting
Energy time-series analysis describes the process of analyzing past energy
observations and possibly external factors so as to predict the future.
Different tasks are involved in the general field of energy time-series
analysis and forecasting, with electric load demand forecasting, personalized
energy consumption forecasting, as well as renewable energy generation
forecasting being among the most common ones. Following the exceptional
performance of Deep Learning (DL) in a broad area of vision tasks, DL models
have successfully been utilized in time-series forecasting tasks. This paper
aims to provide insight into various DL methods geared towards improving the
performance in energy time-series forecasting tasks, with special emphasis in
Greek Energy Market, and equip the reader with the necessary knowledge to apply
these methods in practice.Comment: 13 papges, 4 figure
Enabling efficient and general subpopulation analytics in multidimensional data streams
Today's large-scale services (
e.g.
, video streaming platforms, data centers, sensor grids) need diverse real-time summary statistics across multiple subpopulations of multidimensional datasets. However, state-of-the-art frameworks do not offer general and accurate analytics in real time at reasonable costs. The root cause is the combinatorial explosion of data subpopulations and the diversity of summary statistics we need to monitor simultaneously. We present Hydra, an efficient framework for multidimensional analytics that presents a novel combination of using a "sketch of sketches" to avoid the overhead of monitoring exponentially-many subpopulations and universal sketching to ensure accurate estimates for multiple statistics. We build Hydra as an Apache Spark plugin and address practical system challenges to minimize overheads at scale. Across multiple real-world and synthetic multidimensional datasets, we show that Hydra can achieve robust error bounds and is an order of magnitude more efficient in terms of operational cost and memory footprint than existing frameworks (e.g., Spark, Druid) while ensuring interactive estimation times.Red Hat; CNS-2107086 - National Science Foundation; CNS-2106946 - National Science Foundation; CNS-2132643 - National Science FoundationPublished versio
Leveraging Deep Learning and Online Source Sentiment for Financial Portfolio Management
Financial portfolio management describes the task of distributing funds and
conducting trading operations on a set of financial assets, such as stocks,
index funds, foreign exchange or cryptocurrencies, aiming to maximize the
profit while minimizing the loss incurred by said operations. Deep Learning
(DL) methods have been consistently excelling at various tasks and automated
financial trading is one of the most complex one of those. This paper aims to
provide insight into various DL methods for financial trading, under both the
supervised and reinforcement learning schemes. At the same time, taking into
consideration sentiment information regarding the traded assets, we discuss and
demonstrate their usefulness through corresponding research studies. Finally,
we discuss commonly found problems in training such financial agents and equip
the reader with the necessary knowledge to avoid these problems and apply the
discussed methods in practice
Integrated Management of European Cherry Fruit Fly Rhagoletis cerasi (L.): Situation in Switzerland and Europe
Abstract: The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is a highly destructive pest. The low tolerance for damaged fruit requires preventive insecticide treatments for a marketable crop. The phase-out of old insecticides threatens cherry production throughout the European Union (EU). Consequently, new management techniques and tools are needed. With the increasing number of dwarf tree orchards covered against rain to avoid fruit splitting, crop netting has become a viable, cost-effective method of cherry fruit fly control. Recently, a biocontrol method using the entomopathogenic fungus Beauveria bassiana has been developed for organic agriculture. However, for most situations, there is still a lack of efficient and environmentally sound insecticides to control this pest. This review summarizes the literature from over one hundred years of research on R. cerasi with focus on the biology and history of cherry fruit fly control as well as on antagonists and potential biocontrol organisms. We will present the situation of cherry fruit fly regulation in different European countries, give recommendations for cherry fruit fly control, show gaps in knowledge and identify future research opportunities
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