1,721,146 research outputs found
Revealing Pairs-trading opportunities with long short-term memory networks
Full text linkThis work examines a deep learning approach to complement investors’ practices for the identification of pairs-trading opportunities among cointegrated stocks. We refer to the reversal effect, consisting in the fact that temporarily market deviations are likely to correct and finally converge again, to generate valuable pairs-trading signals based on the application of Long Short-Term Memory networks (LSTM). Specifically, we propose to use the LSTM to estimate the probability of a stock to exhibit increasing market returns in the near future compared to its peers, and we compare and combine these predictions with trading practices based on sorting stocks according to either price or returns gaps. In so doing, we investigate the ability of our proposed approach to provide valuable signals under different perspectives including variations in the investment horizons, transaction costs and weighting schemes. Our analysis shows that strategies including such predictions can contribute to improve portfolio performances providing predictive signals whose information content goes above and beyond the one embedded in both price and returns gaps
A tale of two layers: The mutual relationship between bitcoin and lightning network
Full text linkA major concern of the adoption and scalability of Blockchain technologies refers to their efficient use for payments. In this work, we analyze how Lightning Network (LN), which represents a relevant infrastructural novelty, is influenced by the market dynamics of its referring cryptocurrency, namely Bitcoin. In so doing, we focus on how the LN is efficient in performing transactions and we relate this feature to the market conditions of Bitcoin. By applying the Toda–Yamamoto variant of Granger-causality, we note that market conditions of Bitcoin do not significantly influence the topological configuration of the LN. Hence, although the LN represents a second layer on the Bitcoin blockchain, our findings suggest that its efficient functioning does not appear to be related to the simple market performance of its underlying cryptocurrency and, in particular, of its volatile market fluctuations. This result may therefore contribute to shed light on the practical usage of the LN as a blockchain technology to favor transactions
[Nphe(1)]nociceptin-(1-13)NH(2) selectively antagonizes nociceptin effects in the rabbit isolated ileum
No full textPharmacological characterization of a vasopressin V1 receptor in the isolated human gastric artery
No full textSpecies-related specific differences in the pharmacological profile of vasopressin V1a receptors have been reported. Thus, the aim of the present study was to identify a vascular preparation of human origin expressing V1a receptors. Vasopressin was found to contract human gastric artery strips without endothelium with high affinity (pEC50 8.9). The maximal effect induced by vasopressin was inversely related to the diameter of the vessel. Oxytocin was found to contract the human gastric artery strips with low potency (pEC50 7.2). Contraction induced by vasopressin was competitively antagonized by the non peptide vasopressin receptor antagonists SR 49059 (pA2 9.2), OPC 21268 (pA2 6.2) and OPC 31260 (pA2 7.1). The order of potency of agonists (vasopressin > > oxytocin) and of antagonists (SR 49059 > > OPC 31260 > OPC 21268) indicate the contraction induced by vasopressin in the isolated human gastric artery is mediated by the V1a receptor type. The present data are similar to those obtained in different preparations expressing the native human V1a receptor as well as to those obtained in cell transfected with this receptor. The human gastric artery is a monoreceptor system of great utility for studying the effects of new drugs interacting with the human V1a receptor
Pharmacology of nociceptin and its receptor: a novel therapeutic target
No full textNociceptin (NC), alias Orphanin FQ, has been recently identified as the endogenous ligand of the opioid receptor-like 1 receptor (OP(4)). This new NC/OP(4) receptor system belongs to the opioid family and has been characterized pharmacologically with functional and binding assays on native (mouse, rat, guinea-pig) and recombinant (human) receptors, by using specific and selective agonists (NC, NC(1 - 13)NH(2)) and a pure and competitive antagonist, [Nphe(1)]NC(1 - 13)NH(2). The similar order of potency of agonists and affinity values of the antagonist indicate that the same receptor is present in the four species. OP(4) is expressed in neurons, where it reduces activation of adenylyl cyclase and Ca(2+) channels while activating K(+) channels in a manner similar to opioids. In this way, OP(4) mediates inhibitory effects in the autonomic nervous system, but its activities in the central nervous system can be either similar or opposite to those of opioids. In vivo experiments have demonstrated that NC modulates a variety of biological functions ranging from nociception to food intake, from memory processes to cardiovascular and renal functions, from spontaneous locomotor activity to gastrointestinal motility, from anxiety to the control of neurotransmitter release at peripheral and central sites. These actions have been demonstrated using NC and various pharmacological tools, as antisense oligonucleotides targeting OP(4) or the peptide precursor genes, antibodies against NC, an OP(4) receptor selective antagonist and with data obtained from animals in which the receptor or the peptide precursor genes were knocked out. These new advances have contributed to better understanding of the pathophysiological role of the NC/OP(4) system, and ultimately will help to identify the therapeutic potential of new OP(4) receptor ligands
Pharmacological characterisation of novel kinin B2 receptor ligands
No full textPeptide and nonpeptide compounds have been shown to interact specifically with B2 receptors of three different
species, namely human, rabbit, and pig. Peptide agonists and nonpeptide antagonists show marked differences in
potencies and suggest the existence of B2 receptor subtypes. This conclusion is based on data obtained with the modified
agonist peptide LF 150943 whose potency (pEC50 9.4) is at least 100-fold higher in rabbit than in humans (7.4)
and pig (6.7). The same conclusion can be drawn from data obtained with antagonists that are more potent in humans (LF
160687, pA2 9.2) than in rabbit (8.7) and pig (8.2) or with antagonists (S 1567) that show the opposite potency order,
being much weaker in humans (pA2 6.9) than in rabbit (7.6) and pig (9.4). Two other compounds (FR 173657 and FR172357) show similar pharmacological spectra as S 1567 and differ from LF 160687
$FAKE: Evidence of spam and bot activity in stock microblogs on twitter
No full textMicroblogs are increasingly exploited for predicting prices and traded volumes of stocks in financial markets. However, it has been demonstrated that much of the content shared in microblogging platforms is created and publicized by bots and spammers. Yet, the presence (or lack thereof) and the impact of fake stock microblogs has never systematically been investigated before. Here, we study 9M tweets related to stocks of the 5 main financial markets in the US. By comparing tweets with financial data from Google Finance, we highlight important characteristics of Twitter stock microblogs. More importantly, we uncover a malicious practice perpetrated by coordinated groups of bots and likely aimed at promoting low-value stocks by exploiting the popularity of high-value ones. Our results call for the adoption of spam and bot detection techniques in all studies and applications that exploit user-generated content for predicting the stock market
Effect of bradykinin antagonists, NG- monomethyl-L- Arginine and L- NG- Nitro - Arginine on phospholipase A2 induced oedema in rat paw.
No full text1. 1. The rat paw oedema produced by a local injection of phospholipase A2 from Naja mocambique mocambique has been shown to be mainly driven by the liberation of serotonin and kinins. 2. 2. Using specific bradykinin receptor antagonists we have shown that kinins are acting through B2 receptors. 3. 3. Using endothelium-derived relaxing factor (EDRF) synthesis inhibitors NG-monomethyl-l-arginine and l-NG-nitro arginine we have tested the possible envolvement of EDRF as mediator. 4. 4. Our work supports the view that extracellular phospholipases A2 are involved in inflammation, and suggests a role for EDRF as mediator of extravasation in this model of inflammatio
- …
