516 research outputs found
Bosonic Helium droplets with cationic impurities: onset of electrostriction and snowball effects from quantum calculations
Variational MonteCarlo and Diffusion MonteCarlo calculations have been
carried out for cations like Li, Na and K as dopants of small
helium clusters over a range of cluster sizes up to about 12 solvent atoms. The
interaction has been modelled through a sum-of-potential picture that
disregards higher order effects beyond atom-atom and atom-ion contributions.
The latter were obtained from highly correlated ab-initio calculations over a
broad range of interatomic distances.
This study focuses on two of the most striking features of the microsolvation
in a quantum solvent of a cationic dopant: electrostriction and snowball
effects. They are here discussed in detail and in relation with the nanoscopic
properties of the interaction forces at play within a fully quantum picture of
the clusters features
War and dissociation : the case of futurist aesthetics
Thanks to their deliberate engagement in state propaganda Italian Futurists deserved a prominent spot in the history of military aesthetics in the 20th century. However, under what looked like an unequivocal expression of support for war, lied a deep philosophical disagreement concerning its existential and epistemological value. The bone of contention concerned the effects of warfare on perception and, consequently, the means of its depiction. The author analyses this intellectual disagreement within the group and focuses, in particular, on its philosophical implications
An investigation of grand battement devant at barre, centre, and in motion using kinematics and electromyography
The purpose of this study was to examine grand battement devant in three conditions: at the barre, in the centre, and traveling. The primary focus was to consider weight transfer in the three conditions, and to examine utilisation of the trunk and lower extremity muscles. An extensive review was done in the dance science literature to determine what previous research had been done related to this subject, and to establish what preliminary work might be needed. As indicated by the literature, in order to achieve this research, it was necessary to develop a dance-specific method for the normalisation of surface electromyography data. In phase one of the research, a dance-specific portable anchored dynamometer was developed and tested. The PAD allowed for the collection of maximum voluntary isometric contractions (MVICs), which could then be used to normalise the sEMG data. In phase two of the research, the grand battement was tested in the three conditions, at the barre, in the centre, and traveling. Forty female dancers volunteered (mean age 30.0 ± 13.0 yrs, mean height 1.63 ± 0.06 m, mean mass 59.0 ± 7.4 kg, and 13.9 ± 13.3 yrs of training in ballet and/or modern dance) and were placed in three groups (Training level): beginner (n = 12), intermediate (n = 14) and advanced (n = 14). Dancers executed five grand battement devant in each of the three conditions (Condition) in randomized order. Data were collected with a 7-camera Vicon motion capture system, two Kistler forceplates, and surface electromyography (EMG), using eight muscles bilaterally. Kinematic data were analysed in three intervals: stance to battement initiation, initiation to battement peak, and peak to end. Four variables were investigated: centre of gravity of the full trunk, centre of gravity of the pelvis, centre of gravity of the upper trunk, and centre of mass. EMG data were analysed in four events: stance, initiation, peak, and end. For weight transfer, the main effect of Condition was significant for all four variables in both the x-axis and the y-axis (p < .001). There were no significant differences for Training and no significant Condition x Training interactions. Muscle use varied according to the combination of event and condition that was executed, and these differences were also influenced by the level of training of the dancer and the side of the body used. It is recommended that dance educators consider the importance of allocating sufficient time to each of the three conditions (barre, centre, and traveling), to ensure development of a variety of motor strategies and muscle activation patterns for dance practice.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Isolation and identification of 3'-amino-3'-deoxyadenosine from Cordyceps militaris
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32269/1/0000331.pd
The Sludge Dewaterability in Advanced Wastewater Treatment: A Survey of Four Different Membrane BioReactor Pilot Plants
The wasted activated sludge dewaterability represents a major concern
for Wastewater Treatment Plants (WWTPs) managers. Indeed, whereas the
dewatered sludge could represents a re-usable matrix, the principal drawback
related to the wasted sludge dewaterability is the high water content due to the
presence of extracellular polymeric substances (EPS) that allow the trapping of
water molecules within the bio sludge flocs. In order to provide an outlook of
the dewaterability features of activated sludge derived from advanced WWTP,
the present research reports a long term survey (over two years) aimed at
assessing the principal dewaterability parameters of the sludge wasted from
different Membrane BioReactor pilot plants
Phosphine-Catalyzed Formation of Carbon-Sulfur Bonds: Catalytic Asymmetric Synthesis of gamma-Thioesters
Supporting Information Available: Experimental procedures and compound characterization data. This material is available free of charge via the Internet at http://pubs.acs.org.A method for catalytic asymmetric γ sulfenylation of carbonyl compounds has been developed. In the presence of an appropriate catalyst, thiols not only add to the γ position of allenoates, overcoming their propensity to add to the β position in the absence of a catalyst, but do so with very good enantioselectivity. Sulfur nucleophiles are now added to the three families of nucleophiles (carbon, nitrogen, and oxygen) that had earlier been shown to participate in catalyzed γ additions. The phosphine catalyst of choice, TangPhos, had previously only been employed as a chiral ligand for transition metals, not as an efficient enantioselective nucleophilic catalyst.National Institutes of Health (U.S.)National Institute of General Medical Sciences (U.S.) (R01-GM57034)Merck & Co.Novartis (Firm
Apšvietimas kaip architektūros modernumo simbolis
The paper is designed to reveal the aesthetics of artificial lighting and its influence on the architecture of the 20th century. The main topics discussed are electric lighting, which appeard in our history at the end of the 19th century, and the technical development of lighting till the middle of the 20th century. Connections of artificial lighting with visual arts, its influence on advertisement, building architecture and the whole city are analysed. An idea is proposed that although lighting by nature was purely functional, very soon it acquired symbolic ambitions to represent architecture. In modern times architects understood that lighting was both a technological development and a symbol of a new era, when there appeared an independent field of creation - lighting architecture.
Santrauka
Straipsnyje nagrinėjama dirbtinio apšvietimo estetika ir jos įtaka XX a. architektūrai. Išryškinta XIX a. pabaigoje atsiradusio elektrinio apšvietimo svarba ir atskleista apšvietimo techninė raida iki XX a. vidurio. Nagrinėjamos dirbtinio apšvietimo sąsajos su vizualiaisiais menais, apšvietimo įtaka reklamai, pastatų architektūrai bei visam miestui. Straipsnyje keliama idėja, kad nors apšvietimo prigimtis pradžioje buvo grynai funkcionali, ji greitai įgavo simbolinių ambicijų – reprezentuoti architektūrą. Architektai į apšvietimą žvelgė ne tik kaip į technologinę pažangą, tai buvo naują erą ženklinantis simbolis, erą, kurioje atsiranda didelės įtakos visoms kūrybinėms idėjoms turinti nauja savarankiška kūrybos sritis – šviesos architektūra.
First Published Online: 22 May 2013
Reikšminiai žodžiai: meninis, dirbtinis, elektrinis apšvietimas, stiklo, šviesos architektūra, modernumas
Spin Glass and Antiferromagnetic Behaviour in a Diluted fcc Antiferromagnet
We report on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc
lattice. This is a typical model example of a highly frustrated
antiferromagnet, and we ask, whether sufficient random dilution of spins does
produce a spin glass phase. Our data strongly indicate the existence of a spin
glass transition for spin--concentration : We find a divergent spin
glass susceptibility and a divergent spin glass correlation length, whereas the
antiferromagnetic correlation length saturates in this regime. Furthermore, we
find a first order phase transition to an antiferromagnet for ,
which becomes continuous in the range . Finite size scaling is
employed to obtain critical exponents. We compare our results with experimental
systems as diluted frustrated antiferromagnets as .Comment: 29 pages (revtex) and 10 figures uuencoded and Z-compresse
Schumpeter: Theorist of the Avant-Garde
This paper argues that Schumpeter’s 1911 edition of ‘Theory of Economic
Development’ can be fruitfully read as a theory of the avant-garde, in line with such
theories developed by artistic avant-garde around the same time, in particular by the
Italian Futurists. In particular it will show that both Schumpeter and other avant-garde
theorists sought to break with past (1), identify an avant-garde who could force that
break (2), find new ways to represent the dynamic world (3), embrace the new and
dynamic (4) and promote a perpetual dynamic process, instead of a specific end-state or
utopia (5). This new reading helps us to understand the cultural meaning of this seminal
text in economics. Secondly it greatly facilitates our understanding of the differences
with the later interwar German edition and English edition, which were more cautious
in their embrace of the new, less focused on the individual qualities of the entrepreneur
and placed more emphasis on historical continuity. Thirdly this reading suggests a
different reason for the bifurcation between Schumpeter and the rest of the Austrian
school of economics. Traditionally this split is explained by Schumpeter’s affinities
with the Lausanne School, this paper instead suggests that the crucial break between
Schumpeter on the one hand and Böhm-Bawerk, Wieser and later members of the
Austrian School on the other hand is their theory of and attitude toward social change
Mutation of a single residue, β-glutamate-20, alters protein–lipid interactions of light harvesting complex II
It is well established that assembly of the peripheral antenna complex, LH2, is required for proper photosynthetic membrane biogenesis in the purple bacterium Rhodobacter sphaeroides. The underlying interactions are, as yet, not understood. Here we examined the relationship between the morphology of the photosynthetic membrane and the lipid–protein interactions at the LH2–lipid interface. The non-bilayer lipid, phosphatidylethanolamine, is shown to be highly enriched in the boundary lipid phase of LH2. Sequence alignments indicate a putative lipid binding site, which includes β-glutamate-20 and the adjacent carotenoid end group. Replacement of β-glutamate-20 with alanine results in significant reduction of phosphatidylethanolamine and concomitant raise in phosphatidylcholine in the boundary lipid phase of LH2 without altering the lipid composition of the bulk phase. The morphology of the LH2 housing membrane is, however, unaffected by the amino acid replacement. In contrast, simultaneous modification of glutamate-20 and exchange of the carotenoid sphaeroidenone with neurosporene results in significant enlargement of the vesicular membrane invaginations. These findings suggest that the LH2 complex, specifically β-glutamate-20 and the carotenoids' polar head group, contribute to the shaping of the photosynthetic membrane by specific interactions with surrounding lipid molecules
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