5,089 research outputs found
Herbal highs: review on psychoactive effects and neuropharmacology
Background: A new trend among users of new psychoactive substancesâ the consumption of âherbal highsâ: plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction. Objective: We reviewed psychoactive effects and neuropharmacology of the most used âherbal highsâ with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa. Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with âclassicalâ drugs of abuse. Conclusion: Some âherbal highsâ should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking
Enumeration of RNA structures by Matrix Models
We enumerate the number of RNA contact structures according to their genus,
i.e. the topological character of their pseudoknots. By using a recently
proposed matrix model formulation for the RNA folding problem, we obtain exact
results for the simple case of an RNA molecule with an infinitely flexible
backbone, in which any arbitrary pair of bases is allowed. We analyze the
distribution of the genus of pseudoknots as a function of the total number of
nucleotides along the phosphate-sugar backbone.Comment: RevTeX, 4 pages, 2 figure
The educational turn in art: rewriting the hidden curriculum
Around 2006, the art world developed a prolonged fascination with questions of education, pedagogy and the art school. âThe Educational Turnâ (Rogoff, 2008) as it became known, produced a plethora of artistic and curatorial practices that engage with educational paradigms and problematics. Prompted in part by the European Union Bologna Process, the Educational Turn provided a critique of education as one-directional knowledge transfer, and the framing of education as a commercialised industry, reduced to the utilitarianism of training for working life. At the same time, it established âeducationâ as a thematic for the art world, in most cases divorced from its capacity for producing change in the fields of art or education. This article asks, what is the hidden curriculum (Illich) of this Educational Turn? Drawing from the writings of Colin Crouch, Wolfgang Streeck and Paulo Virno among others, it suggests that such âturnsâ without a vital link to the realm of action, contribute to the broader problematic of public programming without a public sphere, through which formerly democratic institutions (like art galleries) operate as shells in a capitalist environment that is increasingly incompatible with democracy. We read The Education Turn here as a missed opportunity to re-shape art curricula and institutions, to develop a movement to oppose the Bologna Accord and the brutal changes imposed on art education through austerity politics. Finally, we argue - citing the writings of Paulo Friere, the mutualist movements in Europe of the 18th and 19th centuries, the educational experiments of Celestin Freinet in and Fernand Oury in France in the 1950s and the pedagogies of feminist and post-colonial struggle - for a deeper connection to radical education genealogies and their contemporary counterparts in contemporary public programming today
Topology of Luminous Red Galaxies from the Sloan Digital Sky Survey
We present measurements of the genus topology of luminous red galaxies (LRGs)
from the Sloan Digital Sky Survey (SDSS) Data Release 7 catalog, with
unprecedented statistical significance. To estimate the uncertainties in the
measured genus, we construct 81 mock SDSS LRG surveys along the past light cone
from the Horizon Run 3, one of the largest N-body simulations to date that
evolved 7210^3 particles in a 10815 Mpc/h size box. After carefully modeling
and removing all known systematic effects due to finite pixel size, survey
boundary, radial and angular selection functions, shot noise and galaxy
biasing, we find the observed genus amplitude to reach 272 at 22 Mpc/h
smoothing scale with an uncertainty of 4.2%; the estimated error fully
incorporates cosmic variance. This is the most accurate constraint of the genus
amplitude to date, which significantly improves on our previous results. In
particular, the shape of the genus curve agrees very well with the mean
topology of the SDSS LRG mock surveys in the LCDM universe. However, comparison
with simulations also shows small deviations of the observed genus curve from
the theoretical expectation for Gaussian initial conditions. While these
discrepancies are mainly driven by known systematic effects such as those of
shot noise and redshift-space distortions, they do contain important
cosmological information on the physical effects connected with galaxy
formation, gravitational evolution and primordial non-Gaussianity. We address
here the key role played by systematics on the genus curve, and show how to
accurately correct for their effects to recover the topology of the underlying
matter. In a forthcoming paper, we provide an interpretation of those
deviations in the context of the local model of non-Gaussianity.Comment: 23 pages, 18 figures. APJ Supplement Series 201
Unbiased estimates of galaxy scaling relations from photometric redshift surveys
Many physical properties of galaxies correlate with one another, and these
correlations are often used to constrain galaxy formation models. Such
correlations include the color-magnitude relation, the luminosity-size
relation, the Fundamental Plane, etc. However, the transformation from
observable (e.g. angular size, apparent brightness) to physical quantity
(physical size, luminosity), is often distance-dependent. Noise in the distance
estimate will lead to biased estimates of these correlations, thus compromising
the ability of photometric redshift surveys to constrain galaxy formation
models. We describe two methods which can remove this bias. One is a
generalization of the V_max method, and the other is a maximum likelihood
approach. We illustrate their effectiveness by studying the size-luminosity
relation in a mock catalog, although both methods can be applied to other
scaling relations as well. We show that if one simply uses photometric
redshifts one obtains a biased relation; our methods correct for this bias and
recover the true relation
Vibrational properties of inclusion complexes: the case of indomethacin-cyclodextrin
Vibrational properties of inclusion complexes with cyclodextrins are studied
by means of Raman spectroscopy and numerical simulation. In particular, Raman
spectra of the non-steroidal, anti-inflammatory drug indomethacin undergo
notable changes in the energy range between 1600 and 1700 cm when
inclusion complexes with cyclodextrins are formed. By using both \emph{ab
initio} quantum chemical calculations and molecular dynamics, we studied how to
relate such changes to the geometry of the inclusion process, disentangling
single-molecule effects, from changes in the solid state structure or
dimerization processes.Comment: 14 file figure
Market Power and Patent Strategies: Evidence from Renaissance Venice
This paper exploits the introduction of the first regularized patent system, which appeared in the Venetian Republic in 1474, to examine the factors shaping inventors\u2019 propensity to use a new form of intellectual property. We combine detailed information on craft guilds and patents in Renaissance Venice and show a negative association between patenting activity and guild statutory norms that strongly restricted entry and price competition. Our analysis shows that the heterogeneity in patenting activity documented by the industrial organization literature is not a special feature of modern technologies, but is rather a persistent phenomenon affected by market power
Hepatotoxicity induced by greater celandine (Chelidonium majus L.): a review of the literature
The available literature assessing Chelidonium majus L. (CM) hepatotoxicity potential, and its risk to benefit assessment has been reviewed in this paper. Identification of significant scientific literature was performed via the following research databases: Cochrane Central, Google Scholar, EMBASE, Medline, Science Direct, Scopus, Web of Science, using the following keywords: "Chelidonium majus", "greater celandine", "Hepatotoxicity", "Liver" "Injury", "Toxicity" individually investigated and then again in association. CM named also greater celandine, swallow-wort, or bai-qu-cai (Chinese), has been used for a long time in traditional Chinese medicine and phytotherapy. Its extracts have been claimed to display a wide variety of biological activities: antimicrobial, anti-inflammatory, spasmolytic, antineoplastic, hepatoprotective, and analgesic. Moreover, herbal medicine suggests this plant have numerous additional effects which have not yet been scientifically evaluated, such as antitussive, diuretic, and eye-regenerative. However, despite its claimed hepatoprotective effects, several hepatotoxicity cases have been reported to be probably or highly probably connected with CM exposure, after their evaluation through liver-targeted causality assessment methods. CM hepatotoxicity has been defined as a distinct form of herb-induced liver injury (HILI), due to an idiosyncratic reaction of the metabolic type. This evidence has to be considered in relationship with the absence of considerable benefits of CM therapy. Therefore, the risk to benefit ratio of the use of herbal products containing greater celandine can actually be considered as negative
Consciousness Explained or Described?
Consciousness is an unusual phenomenon to study scientifically. It is defined as a subjective, first-person phenomenon, and science is an objective, third-person endeavor. This misalignment between the meansâscienceâand the endâexplaining consciousnessâgave rise to what has become a productive workaround: the search for âneural correlates of consciousnessâ (NCCs). Science can sidestep trying to explain consciousness and instead focus on characterizing the kind(s) of neural activity that are reliably correlated with consciousness. However, while we have learned a lot about consciousness in the bargain, the NCC approach was not originally intended as the foundation for a true explanation of consciousness. Indeed, it was proposed precisely to sidestep the, arguably futile, attempt to find one. So how can an account, couched in terms of neural correlates, do the work that a theory is supposed to do: explain consciousness? The answer is that it cannot, and in fact most modern accounts of consciousness do not pretend to. Thus, here, we challenge whether or not any modern accounts of consciousness are in fact theories at all. Instead we argue that they are (competing) laws of consciousness. They describe what they cannot explain, just as Newton described gravity long before a true explanation was ever offered. We lay out our argument using a variety of modern accounts as examples and go on to argue that at least one modern account of consciousness, attention schema theory, goes beyond describing consciousness-related brain activity and qualifies as an explanatory theory
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