Numerical calculation of the combinatorial entropy of partially ordered ice

Using a one-parameter case as an example, we demonstrate that multicanonical simulations allow for accurate estimates of the residual combinatorial entropy of partially ordered ice. For the considered case corrections to an (approximate) analytical formula are found to be small, never exceeding 0.5%. The method allows one as well to calculate combinatorial entropies for many other systems.Comment: Extended version: 7 pages, 10 figures (v1 is letter-type version

Magnetic charge and ordering in kagome spin ice

We present a numerical study of magnetic ordering in spin ice on kagome, a two-dimensional lattice of corner-sharing triangles. The magnet has six ground states and the ordering occurs in two stages, as one might expect for a six-state clock model. In spin ice with short-range interactions up to second neighbors, there is an intermediate critical phase separated from the paramagnetic and ordered phases by Kosterlitz-Thouless transitions. In dipolar spin ice, the intermediate phase has long-range order of staggered magnetic charges. The high and low-temperature phase transitions are of the Ising and 3-state Potts universality classes, respectively. Freeze-out of defects in the charge order produces a very large spin correlation length in the intermediate phase. As a result of that, the lower-temperature transition appears to be of the Kosterlitz-Thouless type.Comment: 20 pages, 12 figures, accepted version with minor change

Медіальний поворот у філософії

The article deals with the philosophical interpretation of the media concept. Philosophy of media is one of the most topical trends of modern philosophy. The purpose of the given article is to study the directions of conceptualization of media in philosophy of the second half of the XX century – the beginning of the XXI century. The most popular definition of the term media is «mass media», or «communication media». From the second half of the XX century this definition is regularly reproduced in various types of philosophical research, which deal with the critics of mass media/communication media. The founders of the Frankfurt School criticize media as a constituent of the culture industry. The philosophers of the school of cultural research carry out the analysis of the ideology of the retransmitted mass media. There is another interpretation of the media concept as «material factors of communication processes». The Canadian theorist of culture M. McLuhan considers media to be not only the means of the communication, but also a message. Therein the concept of «media» becomes the central tool for studying transformations of culture. The further development of the given direction in interpretation of media can be found in the research of W. Ong, F. Kittler, R. Debray. In a number of modern philosophical conceptions the media concept is defined even more broadly and is corresponded to the concept of language (D. Mersch, L. Wiesing, M. Vogel, V. Savchuk). The given directions of mediaphilosophy are the result of the linguisticturn, which designated language to be the central philosophical problem. The medialturn in modern philosophy is an extension of the linguisticturn and is one of the most important tendencies of hot cognition. Стаття присвячена дослідженню філософських концептуалізацій медіа. Філософія медіа – один з найбільш актуальних напрямків сучасної філософії. Мета статті – дослідити лінії концептуалізації медіа у філософії другої половини ХХ – початку ХХІ сторіччя. Найбільш популярним значенням імені медіа є «засіб масової інформації», або «засіб масової комунікації». З другої половини ХХ сторіччя це значення регулярно відтворюється у різних філософських дослідженнях, які звертаються до критики масової інформації/комунікації. Філософи критикують медіа як складову культурної індустрії або проводять аналіз ідеології, що ретранслюється мас­медіа. Існує також і друге значення концепту медіа – «матеріальні фактори комунікаційних процесів». Канадський теоретик культури М. Маклюен розглядає медіа не тільки як засіб комунікації, але і як повідомлення. Ім’я медіа тут стає центральним інструментом вивчення трансформацій культури. Подальший розвиток ця лінія знаходить у дослідженнях В.Онга, Ф.Кіттлера, Р.Дебре. У ряді сучасних філософських концепцій поняття медіа визначається ще ширше і співвідноситься з поняттям мова (Д.Мерш, Л.Візінг, М.Фогель, В.Савчук). Означені лінії філософії медіа є результатом лінгвістичного повороту, який визначив мову центральною філософською проблемою. Медіальний поворот у сучасній філософії є продовженням лінгвістичного повороту і складає одну з найбільш важливих тенденцій актуального мислення.Стаття присвячена дослідженню філософських концептуалізацій медіа. Філософія медіа – один з найбільш актуальних напрямків сучасної філософії. Мета статті – дослідити лінії концептуалізації медіа у філософії другої половини ХХ – початку ХХІ сторіччя. Найбільш популярним значенням імені медіа є «засіб масової інформації», або «засіб масової комунікації». З другої половини ХХ сторіччя це значення регулярно відтворюється у різних філософських дослідженнях, які звертаються до критики масової інформації/комунікації. Філософи критикують медіа як складову культурної індустрії або проводять аналіз ідеології, що ретранслюється мас­медіа. Існує також і друге значення концепту медіа – «матеріальні фактори комунікаційних процесів». Канадський теоретик культури М. Маклюен розглядає медіа не тільки як засіб комунікації, але і як повідомлення. Ім’я медіа тут стає центральним інструментом вивчення трансформацій культури. Подальший розвиток ця лінія знаходить у дослідженнях В.Онга, Ф.Кіттлера, Р.Дебре. У ряді сучасних філософських концепцій поняття медіа визначається ще ширше і співвідноситься з поняттям мова (Д.Мерш, Л.Візінг, М.Фогель, В.Савчук). Означені лінії філософії медіа є результатом лінгвістичного повороту, який визначив мову центральною філософською проблемою. Медіальний поворот у сучасній філософії є продовженням лінгвістичного повороту і складає одну з найбільш важливих тенденцій актуального мислення

Medial turn in philosophy

The article deals with the philosophical interpretation of the media concept. Philosophy of media is one of the most topical trends of modern philosophy. The purpose of the given article is to study the directions of conceptualization of media in philosophy of the second half of the XX century – the beginning of the XXI century. The most popular definition of the term media is «mass media», or «communication media». From the second half of the XX century this definition is regularly reproduced in various types of philosophical research, which deal with the critics of mass media/communication media. The founders of the Frankfurt School criticize media as a constituent of the culture industry. The philosophers of the school of cultural research carry out the analysis of the ideology of the retransmitted mass media. There is another interpretation of the media concept as «material factors of communication processes». The Canadian theorist of culture M. McLuhan considers media to be not only the means of the communication, but also a message. Therein the concept of «media» becomes the central tool for studying transformations of culture. The further development of the given direction in interpretation of media can be found in the research of W. Ong, F. Kittler, R. Debray. In a number of modern philosophical conceptions the media concept is defined even more broadly and is corresponded to the concept of language (D. Mersch, L. Wiesing, M. Vogel, V. Savchuk). The given directions of mediaphilosophy are the result of the linguisticturn, which designated language to be the central philosophical problem. The medialturn in modern philosophy is an extension of the linguisticturn and is one of the most important tendencies of hot cognition

GRAPHO-ANALYTICAL MODELING OF PROCESSES OF INTERACTION OF ELEMENTARY COMPONENTS OF A MANAGEMENT PAIR

In order to analyze and justify the choice of the recommended modes of interaction of people in organizational entities, the article covers the main possibilities of increasing the effectiveness of human interaction on the basis of interpreting a typical management pair in the form of two elementary components that can interact in the "subject-object", "subject-subject”, “object-subject” and “object-object” modes, taking into account the fact that each component is characterized by a certain level of subjectivity. At the same time, the authors take into account the fact that during the life of a person and its life cycle in an organizational formation the level of subjectivity of any person varies within the boundary of the linear continuum object - subject, and its subjectity in organizational formation is defined by no means other, as the current state of the ratio of the number of formal and informal influences of the individual as a subject to other members of the organization to the number of the same effects on it as an object from other members of the organization. Due to the fact that the life cycles of the elementary components are characterized by the presence of each of the periods of increase in subjectivity with the achievement of each peak value and the subsequent gradual loss after release or retirement, it is demonstrated that the joint and equally effective activity of the components is possible only provided that they maintain the subject-subject mode of interaction, which corresponds to the dialogue of the two parties, rather than management of or management by one side of the other. Using the superposition of graph- analytic dependencies of Dunig-Kruger and changes in subjectivity throughout life, it is proved that the basic condition for the implementation of such a managerial dialogue is the awareness of both components of the managerial pair of the fact that the concept of the subject loses meaning without the existence of the object, and therefore maintaining the process of dialogue-cooperation is possible only under the condition of equality and freedom of the participants and the inter-orientation of each of the partners as the subject, the tool for establishing partnerships is management on the basis of the dialogue communication process with the mutual recognition of each of the participants in their freedom, equality and value - subjectivity. It has been established that the priority factors determining the results of the operation of a typical management pair are not the structure and the relationship between its constituent elements, but the intellectual, moral and psychological characteristics of these elements and the awareness of the latter as partners that jointly solve the problem with the achievement of mutually established and harmonized goals.In order to analyze and justify the choice of the recommended modes of interaction of people in organizational entities, the article covers the main possibilities of increasing the effectiveness of human interaction on the basis of interpreting a typical management pair in the form of two elementary components that can interact in the "subject-object", "subject-subject”, “object-subject” and “object-object” modes, taking into account the fact that each component is characterized by a certain level of subjectivity. At the same time, the authors take into account the fact that during the life of a person and its life cycle in an organizational formation the level of subjectivity of any person varies within the boundary of the linear continuum object - subject, and its subjectity in organizational formation is defined by no means other, as the current state of the ratio of the number of formal and informal influences of the individual as a subject to other members of the organization to the number of the same effects on it as an object from other members of the organization. Due to the fact that the life cycles of the elementary components are characterized by the presence of each of the periods of increase in subjectivity with the achievement of each peak value and the subsequent gradual loss after release or retirement, it is demonstrated that the joint and equally effective activity of the components is possible only provided that they maintain the subject-subject mode of interaction, which corresponds to the dialogue of the two parties, rather than management of or management by one side of the other. Using the superposition of graph- analytic dependencies of Dunig-Kruger and changes in subjectivity throughout life, it is proved that the basic condition for the implementation of such a managerial dialogue is the awareness of both components of the managerial pair of the fact that the concept of the subject loses meaning without the existence of the object, and therefore maintaining the process of dialogue-cooperation is possible only under the condition of equality and freedom of the participants and the inter-orientation of each of the partners as the subject, the tool for establishing partnerships is management on the basis of the dialogue communication process with the mutual recognition of each of the participants in their freedom, equality and value - subjectivity. It has been established that the priority factors determining the results of the operation of a typical management pair are not the structure and the relationship between its constituent elements, but the intellectual, moral and psychological characteristics of these elements and the awareness of the latter as partners that jointly solve the problem with the achievement of mutually established and harmonized goals

Structural and Magnetic Investigations of Single-Crystals of the Neodymium Zirconate Pyrochlore, Nd2Zr2O7

We report structural and magnetic properties studies of large high quality single-crystals of the frustrated magnet, Nd$_2$Zr$_2$O$_7$. Powder x-ray diffraction analysis confirms that Nd$_2$Zr$_2$O$_7$ adopts the pyrochlore structure. Room-temperature x-ray diffraction and time-of-flight neutron scattering experiments show that the crystals are stoichiometric in composition with no measurable site disorder. The temperature dependence of the magnetic susceptibility shows no magnetic ordering at temperatures down to 0.5 K. Fits to the magnetic susceptibility data using a Curie-Weiss law reveal a ferromagnetic coupling between the Nd moments. Magnetization versus field measurements show a local Ising anisotropy along the axes of the Nd$^{3+}$ ions in the ground state. Specific heat versus temperature measurements in zero applied magnetic field indicate the presence of a thermal anomaly below $T\sim7$ K, but no evidence of magnetic ordering is observed down to 0.5 K. The experimental temperature dependence of the single-crystal bulk dc susceptibility and isothermal magnetization are analyzed using crystal field theory and the crystal field parameters and exchange coupling constants determined.Comment: 10 pages, 6 figures, 4 tables. Accepted for publication in Physical Review

Energy benchmarks for water clusters and ice structures from an embedded many-body expansion

We show how an embedded many-body expansion (EMBE) can be used to calculate accurate \emph{ab initio} energies of water clusters and ice structures using wavefunction-based methods. We use the EMBE described recently by Bygrave \emph{et al.} (J. Chem. Phys. \textbf{137}, 164102 (2012)), in which the terms in the expansion are obtained from calculations on monomers, dimers, etc. acted on by an approximate representation of the embedding field due to all other molecules in the system, this field being a sum of Coulomb and exchange-repulsion fields. Our strategy is to separate the total energy of the system into Hartree-Fock and correlation parts, using the EMBE only for the correlation energy, with the Hartree-Fock energy calculated using standard molecular quantum chemistry for clusters and plane-wave methods for crystals. Our tests on a range of different water clusters up to the 16-mer show that for the second-order M\o{}ller-Plesset (MP2) method the EMBE truncated at 2-body level reproduces to better than 0.1 m$E_{\rm h}$/monomer the correlation energy from standard methods. The use of EMBE for computing coupled-cluster energies of clusters is also discussed. For the ice structures Ih, II and VIII, we find that MP2 energies near the complete basis-set limit reproduce very well the experimental values of the absolute and relative binding energies, but that the use of coupled-cluster methods for many-body correlation (non-additive dispersion) is essential for a full description. Possible future applications of the EMBE approach are suggested

Extreme 13C depletion of CCl2F2 in firn air samples from NEEM, Greenland

A series of 12 high volume air samples collected from the S2 firn core during the North Greenland Eemian Ice Drilling (NEEM) 2009 campaign have been measured for mixing ratio and stable carbon isotope composition of the chlorofluorocarbon CFC-12 (CCl2F2). While the mixing ratio measurements compare favorably to other firn air studies, the isotope results show extreme 13C depletion at the deepest measurable depth (65 m), to values lower than d13C = -80‰ vs. VPDB (the international stable carbon isotope scale), compared to present day surface tropospheric measurements near -40‰. Firn air modeling was used to interpret these measurements. Reconstructed atmospheric time series indicate even larger depletions (to -120‰) near 1950 AD, with subsequent rapid enrichment of the atmospheric reservoir of the compound to the present day value. Mass-balance calculations show that this change is likely to have been caused by a large change in the isotopic composition of anthropogenic CFC-12 emissions, probably due to technological advances in the CFC production process over the last 80 yr, though direct evidence is lacking