823 research outputs found
Statistical mechanical description of liquid systems in electric field
We formulate the statistical mechanical description of liquid systems for
both polarizable and polar systems in an electric field in the
-ensemble, which is the pendant to the thermodynamic description in
terms of the free energy at constant potential. The contribution of the
electric field to the configurational integral in
the -ensemble is given in an exact form as a factor in the
integrand of . We calculate the contribution of the
electric field to the Ornstein-Zernike formula for the scattering function in
the -ensemble. As an application we determine the field induced
shift of the critical temperature for polarizable and polar liquids, and show
that the shift is upward for polarizable liquids and downward for polar
liquids.Comment: 6 page
Breaking the silence of the 500-year-old smiling garden of everlasting flowers: The En Tibi book herbarium
We reveal the enigmatic origin of one of the earliest surviving botanical collections. The 16th-century Italian En Tibi herbarium is a large, luxurious book with c. 500 dried plants, made in the Renaissance scholarly circles that developed botany as a distinct discipline. Its Latin inscription, translated as “Here for you a smiling garden of everlasting flowers”, suggests that this herbarium was a gift for a patron of the emerging botanical science. We follow an integrative approach that includes a botanical similarity estimation of the En Tibi with contemporary herbaria (Aldrovandi, Cesalpino, “Cibo”, Merini, Estense) and analysis of the book’s watermark, paper, binding, handwriting, Latin inscription and the morphology and DNA of hairs mounted under specimens. Rejecting the previous origin hypothesis (Ferrara, 1542–1544), we show that the En Tibi was made in Bologna around 1558. We attribute the En Tibi herbarium to Francesco Petrollini, a neglected 16th-century botanist, to whom also belongs, as clarified herein, the controversial “Erbario Cibo” kept in Rome. The En Tibi was probably a work on commission for Petrollini, who provided the plant material for the book. Other people were apparently involved in the compilation and offering of this precious gift to a yet unknown person, possibly the Habsburg Emperor Ferdinand I. The En Tibi herbarium is a Renaissance masterpiece of art and science, representing the quest for truth in herbal medicine and botany. Our multidisciplinary approach can serve as a guideline for deciphering other anonymous herbaria, kept safely “hidden” in treasure rooms of universities, libraries and museums
Interfaces in Diblocks: A Study of Miktoarm Star Copolymers
We study AB miktoarm star block copolymers in the strong segregation
limit, focussing on the role that the AB interface plays in determining the
phase behavior. We develop an extension of the kinked-path approach which
allows us to explore the energetic dependence on interfacial shape. We consider
a one-parameter family of interfaces to study the columnar to lamellar
transition in asymmetric stars. We compare with recent experimental results. We
discuss the stability of the A15 lattice of sphere-like micelles in the context
of interfacial energy minimization. We corroborate our theory by implementing a
numerically exact self-consistent field theory to probe the phase diagram and
the shape of the AB interface.Comment: 12 pages, 11 included figure
Recommended from our members
Spectroscopy of geo-neutrinos from 2056 days of Borexino data
We report an improved geo-neutrino measurement with Borexino from 2056 days
of data taking. The present exposure is
protonyr. Assuming a chondritic Th/U mass ratio of 3.9, we obtain geo-neutrino events. The null
observation of geo-neutrinos with Borexino alone has a probability of (5.9). A geo-neutrino signal from the mantle is
obtained at 98\% C.L. The radiogenic heat production for U and Th from the
present best-fit result is restricted to the range 23-36 TW, taking into
account the uncertainty on the distribution of heat producing elements inside
the Earth.Comment: 4 pages, 4 figure
Sacrificial-Post Templating Method for Block Copolymer Self-Assembly
A sacrificial-post templating method is presented for directing block copolymer self-assembly to form nanostructures consisting of monolayers and bilayers of microdomains. In this approach, the topographical post template is removed after self-assembly and therefore is not incorporated into the final microdomain pattern. Arrays of nanoscale holes of different shapes and symmetries, including mesh structures and perforated lamellae with a bimodal pore size distribution, are produced. The ratio of the pore sizes in the bimodal distributions can be varied via the template pitch, and agrees with predictions of self consistent field theory.Semiconductor Research CorporationFENA CenterSemiconductor Research Corporation. Nanoscale Research InitiativeSingapore-MIT AllianceNational Science Foundation (U.S.)Tokyo Electron LimitedTaiwan Semicondcutor Manufacturing Compan
The Main Results of the Borexino Experiment
The main physical results on the registration of solar neutrinos and the
search for rare processes obtained by the Borexino collaboration to date are
presented.Comment: 8 pages, 8 figgures, To be published as Proceedings of the Third
Annual Large Hadron Collider Physics Conference, St. Petersburg, Russia, 201
Measurement of neutrino flux from the primary proton--proton fusion process in the Sun with Borexino detector
Neutrino produced in a chain of nuclear reactions in the Sun starting from
the fusion of two protons, for the first time has been detected in a real-time
detector in spectrometric mode. The unique properties of the Borexino detector
provided an oppurtunity to disentangle pp-neutrino spectrum from the background
components. A comparison of the total neutrino flux from the Sun with Solar
luminosity in photons provides a test of the stability of the Sun on the
10 years time scale, and sets a strong limit on the power production in
the unknown energy sources in the Sun of no more than 4\% of the total energy
production at 90\% C.L.Comment: 15 pages, 2 tables, 3 figure
Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags
Using the ARGUS detector at the storage ring DORIS II, we have
measured the Michel parameters , , and for
decays in -pair events produced at
center of mass energies in the region of the resonances. Using
as spin analyzing tags, we find , , , , and . In addition, we report
the combined ARGUS results on , , and using this work
und previous measurements.Comment: 10 pages, well formatted postscript can be found at
http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p
Barking up the same tree: a comparison of ethnomedicine and canine ethnoveterinary medicine among the Aguaruna
<p>Abstract</p> <p>Background</p> <p>This work focuses on plant-based preparations that the Aguaruna Jivaro of Peru give to hunting dogs. Many plants are considered to improve dogs' sense of smell or stimulate them to hunt better, while others treat common illnesses that prevent dogs from hunting. This work places canine ethnoveterinary medicine within the larger context of Aguaruna ethnomedicine, by testing the following hypotheses: H1 -- Plants that the Aguaruna use to treat dogs will be the same plants that they use to treat people and H2 -- Plants that are used to treat both people and dogs will be used for the same illnesses in both cases.</p> <p>Methods</p> <p>Structured interviews with nine key informants were carried out in 2007, in Aguaruna communities in the Peruvian department of Amazonas. Informants provided freelists of plants given to dogs and explained the purpose, preparation and route of administration used. For each plant, informants also described any uses for treating people. Botanical voucher specimens were collected and additional informal observations were made, accompanying people on hunting trips.</p> <p>Results</p> <p>Out of 35 plant species given to dogs, 29 (83%) are also given to humans for some medicinal purpose, while five are used only for dogs. However, the same plant is used to treat the same illness in both humans and dogs in only 53% of the cases. Forty-three percent of plants used to treat a particular illness for both dogs and people are administered in the same manner for both.</p> <p>Conclusion</p> <p>Results suggest that Aguaruna canine ethnoveterinary medicine is, at least partly, an independent cognitive domain. Some of the difference in plant use between dogs and people can be explained by the fact that certain diseases mentioned only apply to dogs. Although reports of canine ethnoveterinary medicine are very sparse in the literature, Aguaruna practices show some similarities with a few trends reported for other Amazonian societies, particularly, in the prevalence of the nasal route of administration, the use of plant-based psychoactives and in the importance of ants and wasps, in some form, for training dogs.</p
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