scholarly journals Dueños y poseedores de la naturaleza: la relación artificial-natural en la Dióptrica de Descartes

Author(s):  
Sergio García Rodríguez
Keyword(s):  
One Step ◽  

RESUMENLa interpretación actual de la ciencia cartesiana ya no concibe ésta como una mera deducción desde los principios metafísicos, sino que reivindica el papel de la experiencia en ella. El presente artículo tratará de dar un paso más, defendiendo que existe una dimensión instrumental en la ciencia cartesiana. Para ello, se analizará la modificación que Descartes realiza en la Dióptrica de la relación artificial-natural y que posibilita una lectura instrumentalista.PALABRAS CLAVEDESCARTES, ARTIFICIAL, NATURAL, INSTRUMENTALISMO, CIENCIAABSTRACTThe current interpretation of the Cartesian science no longer sees it as a mere deduction from the metaphysical principles, but claims the role of experience in it. This paper will try to go one step further, arguing that there is an instrumental dimension in the Cartesian science. With this purpose in mind, we will analyze the modification performed by Descartes in the Dioptrics regarding the artifitial-natural relation, which enables this instrumentalist reading.KEYWORDS DESCARTES, ARTIFICIAL, NATURAL, INSTRUMENTALISM, SCIENCE

2019 ◽  
Author(s):  
Bella Grigorenko ◽  
Igor Polyakov ◽  
Alexander Nemukhin

<p>We report a mechanism of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP) conversion by the mammalian type V adenylyl cyclase revealed in molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) simulations. We characterize a set of computationally derived enzyme-substrate (ES) structures showing an important role of coordination shells of magnesium ions in the solvent accessible active site. Several stable six-fold coordination shells of Mg<sub>A</sub><sup>2+ </sup>are observed in MD simulations of ES complexes. In the lowest energy ES conformation, the coordination shell of Mg<sub>A</sub><sup>2+ </sup>does not include the O<sub>δ1</sub> atom of the conserved Asp440 residue. Starting from this conformation, a one-step reaction mechanism is characterized which includes proton transfer from the ribose O<sup>3'</sup>H<sup>3' </sup>group in ATP to Asp440 via a shuttling water molecule and P<sup>A</sup>-O<sup>3A</sup> bond cleavage and O<sup>3'</sup>-P<sup>A</sup> bond formation. The energy profile of this route is consistent with the observed reaction kinetics. In a higher energy ES conformation, Mg<sub>A</sub><sup>2+</sup> is bound to the O<sub>δ1</sub>(Asp440) atom as suggested in the relevant crystal structure of the protein with a substrate analog. The computed energy profile initiated by this ES is characterized by higher energy expenses to complete the reaction. Consistently with experimental data, we show that the Asp440Ala mutant of the enzyme should exhibit a reduced but retained activity. All considered reaction pathways include proton wires from the O<sup>3'</sup>H<sup>3' </sup>group via shuttling water molecules. </p>


2017 ◽  
pp. 126-169
Author(s):  
S.E. Tariverdieva

The article deals with the development of the coregency system of Augustus and Agrippa from 29 to 18 BC: from formal and actual disparity of the coregents to their formal equality with the dominance of the princeps auctoritas. Particular attention is paid to the earlier stages of this development and to the crisis of 23 BC. The coregency system created by Augustus is often regarded by modern historians as means of ensuring uninterrupted succession of power. Agrippa as his coregent often is thought to have assumed the role of the regent who temporally replaces the princeps, just as it was in formal monarchies, or that of the tutor of the future rulers. However, the Roman system of state administration did not allow such type of regency. The princeps coregent, who was his equal in formal credentials but his inferior in terms of auctoritas, in case of the princeps death had to become the next princeps as his immediate successor. It is unlikely that later he was expected to voluntarily give up his power in favour of younger heir and to vanish from the political life altogether. The inheritance system under Augustus was like a ladder with the princeps at the top, the coregent who was also the immediate successor one step below, heirs of the next degree further down. In case of death of one of them, successors shifted one step up. The coregency had one more function: geographically it allowed Augustus and Agrippa to rule jointly the empire while staying in different parts of it.В статье исследуется развитие системы соправления Августа и Агриппы с 29 по 12 гг. до н. э.: от формального и фактического неравенства соправителей до их формального равенства при преобладании auctoritas принцепса, причём особое внимание уделяется раннему этапу этого развития и кризису 23 г. до н. э. Институт соправления, созданный Августом, часто рассматривается, как средство обеспечения бесперебойного перехода власти, причем Агриппе, как соправителю, НЕРЕДКО отводится роль регента, временно замещающего принцепса или воспитателя будущих правителей. Однако римская система государственного управления не предполагала регентства. Соправитель принцепса, равный ему по формальным полномочиям, но уступавший по auctoritas, в случае его смерти должен был СТАТЬ следующим принцепсом, ближайшим его наследником. Вряд ли предполагалось, что в будущем он должен добровольно уступить власть более молодому наследнику и исчезнуть из политической жизни. Система наследования при Августе представляла собой нечто вроде лестницы, на вершине которой стоял принцепс, на следующей ступени соправитель, он же избранный преемник, ниже наследники следующей очереди в случае смерти когото из них происходило продвижение наследников по ступеням вверх. Кроме того, соправление имело и иное значение позволяло Августу и Агриппе совместно управлять империей, находясь в разных ее частях.


Synlett ◽  
2021 ◽  
Author(s):  
Kripa Subramanian ◽  
Subhash L. Yedage ◽  
Kashish Sethi ◽  
Bhalchandra M. Bhanage

An electrochemical method for the synthesis of phenanthridinones via constant potential electrolysis (CPE) mediated by <i>n</i>-Bu<sub>4</sub>NI (TBAI) has been reported. The protocol is metal and oxidant free and proceeds with 100% current efficiency. Here TBAI plays the dual role of the redox catalyst as well as supporting electrolyte. The intramolecular C-H activation proceeds under mild reaction conditions and short reaction time via electrochemically generated amidyl radicals. The reaction has been scaled up to gram level showing its practicability and the synthetic utility and applicability of the protocol has been demonstrated by the direct one-step synthesis of the bioactive compound Phenaglaydon.


2008 ◽  
Vol 24 (10) ◽  
pp. 1412-1419 ◽  
Author(s):  
K.L. Van Landuyt ◽  
J. Snauwaert ◽  
M. Peumans ◽  
J. De Munck ◽  
P. Lambrechts ◽  
...  
Keyword(s):  
One Step ◽  

2018 ◽  
Author(s):  
Yannick Charretier ◽  
Seydina M. Diene ◽  
Damien Baud ◽  
Sonia Chatellier ◽  
Emmanuelle Santiago-Allexant ◽  
...  

AbstractMultidrug-resistant Acinetobacter baumannii infection has recently emerged as a worldwide clinical problem and colistin is increasingly being used as last resort therapy. Despite its favorable bacterial killing, resistance and heteroresistance to colistin have been described. Mutations in the PmrAB regulatory pathway have been already associated with colistin resistance whereas the mechanisms for heteroresistance remain largely unknown. The purpose of the present study is to investigate the role of PmrAB in laboratory-selected mutants representative of global epidemic strains. During brief colistin exposure, colistin resistant and colistin heteroresistant mutants were selected in a one-step strategy. Population Analysis Profiling (PAP) was performed to confirm the suspected phenotype. Upon withdrawal of selective pressure, compensatory mutations were evaluated in another one-step strategy. A trans-complementation assay was designed to delineate the involvement of the PmrAB regulatory system using qPCR and PAP. Mutations in the PmrAB regulatory pathway were associated with colistin resistance and colistin heteroresistance as well. The transcomplementation assay provides a proof for the role played by changes in the PmrAB regulatory pathway. The level of colistin resistance is correlated to the level of expression of pmrC. The resistance phenotype was partially restored since the complemented strain became heteroresistant. This report shows the role of different mutations in the PmrAB regulatory pathway and warns on the development of colistin heteroresistance that could be present but not easily detected with routine testing.


2021 ◽  
Vol 5 (1) ◽  
pp. 35-54
Author(s):  
Fitri Adi Setyorini

This study discusses the International Committee for the Red Cross (ICRC) role in protecting and assisting victims of the Libyan revolution in 2011. The purpose of this study is to explore more about the role of the International Committee for the Red Cross (ICRC) in protecting and assisting victims of war as one step on a humanitarian mission. The author used the non-government organizations (NGOs) and humanitarian action concepts. The author's research method to analyze this study was a descriptive method through a literature review. Based on research done, the author found that the revolution in Libya in 2011 was one of the effects of the Arab Spring in the Middle East region. The author also found that the ICRC carried out its humanitarian missions by providing food, water, medical supplies, medical equipment, and clothing.


2020 ◽  
Author(s):  
Vasileios Tzitzios ◽  
Vishnu Pillai ◽  
Christina Gioti ◽  
Marios Katsiotis ◽  
Thomas Karagiannis ◽  
...  

Nanostructured transition metal phosphides gathered last years an elevated scientific interest, due to their unique physical-chemical properties. Nickel phosphide nanoparticles, with the controllable crystal structure, from the metal rich tetragonal Ni<sub>12</sub>P<sub>5</sub> to the phosphorous rich hexagonal Ni<sub>2</sub>P, and <i>hcp</i> Ni<sub>2</sub>P decorated r-GO (reduced graphene oxide), nano-hybrid materials have been synthesized via a novel one step organometallic approach in primary-tertiary aliphatic amines mixture. The nanoparticles are monodispersed, with spherical shape and controllable size in the sub-10 nm regime and decorate uniformly the surface of the r-GO, leading to the formation of Ni<sub>2</sub>P/r-GO hybrid materials. The materials were characterized by powder XRD, TEM and Raman spectroscopy and catalytically evaluated for the dibenzothiophene hydrodesulphurization (HDS) reaction. The results show that the role of the tertiary amine is crucial for the phosphidation process and the r-GO is an ideal alternative, to the traditional inorganic ones, support for the immobilization of the catalytically active component, preventing significantly sintering effects.


2012 ◽  
Vol 22 (1) ◽  
pp. 37-56 ◽  
Author(s):  
Ryan J. Rabett ◽  
Philip J. Piper

For many decades Palaeolithic research viewed the development of early modern human behaviour as largely one of progress down a path towards the ‘modernity’ of the present. The European Palaeolithic sequence — the most extensively studied — was for a long time the yard-stick against which records from other regions were judged. Recent work undertaken in Africa and increasingly Asia, however, now suggests that the European evidence may tell a story that is more parochial and less universal than previously thought. While tracking developments at the large scale (the grand narrative) remains important, there is growing appreciation that to achieve a comprehensive understanding of human behavioural evolution requires an archaeologically regional perspective to balance this.One of the apparent markers of human modernity that has been sought in the global Palaeolithic record, prompted by finds in the European sequence, is innovation in bonebased technologies. As one step in the process of re-evaluating and contextualizing such innovations, in this article we explore the role of prehistoric bone technologies within the Southeast Asian sequence, where they have at least comparable antiquity to Europe and other parts of Asia. We observe a shift in the technological usage of bone — from a minor component to a medium of choice — during the second half of the Last Termination and into the Holocene. We suggest that this is consistent with it becoming a focus of the kinds of inventive behaviour demanded of foraging communities as they adapted to the far-reaching environmental and demographic changes that were reshaping this region at that time. This record represents one small element of a much wider, much longerterm adaptive process, which we would argue is not confined to the earliest instances of a particular technology or behaviour, but which forms part of an on-going story of our behavioural evolution.


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