Search

Cancer cell metastasis is a major factor in cancer-related mortality. During the process of metastasis, cancer cells exhibit migratory phenotypes and invade through pores in the dense extracellular matrix. However, the characterization of morphological and subcellular features of cells in similar migratory phenotypes and the effects of geometric confinement on cell morphodynamics are not well understood. Here, we investigate the phenotypes of highly aggressive MDA-MB-231 cells in single cell and cell doublet (an initial and simplified collective state) forms in confined microenvironments. We group phenotypically similar single cells and cell doublets and characterize related morphological and subcellular features. We further detect two distinct migratory phenotypes, fluctuating and non-fluctuating, within the fast migrating single cell group. In addition, we demonstrate an increase in the number of protrusions formed at the leading edge of cells after invasion through geometric confinement. Finally, we track the short and long term effects of varied degrees of confinement on protrusion formation. Overall, our findings elucidate the underlying morphological and subcellular features associated with different single cell and cell doublet phenotypes and the impact of invasion through confined geometry on cell behavior.

The basis of the American approach to culture eschews any collective state intervention. Cultural institutions, such as museums, originated as the beneficiaries of private donors. Such philanthropy benefits from a tax code that provides financial incentives for contributions to private organizations. For institutions, funds raised from ancillary activities, such as gift shops, also enjoy significant tax exemptions. Yet, despite these publicly financed tax deductions, cultural visions are privately conceived, and reflect the agendas of the donors. This attitude represents the basic principle of the American patronage system: one that is facilitated by a tax policy, not a cultural policy.

Despite the increasing digitalisation of special collections, Australian university libraries continue to house tangible original works contributing to collective state, national and global heritage. The protection of special collections relates to the international aspirations provided by the Sendai Framework for Disaster Risk Reduction 2015�2030 Priority 3. Currently over five hundred separately grouped university library special collections are recorded in Australia. Globally, there is limited research into university librarian comprehension of how to plan for the protection of special collections. A survey targeted the 35 Australian university libraries identified for inclusion in the study, via the Council for Australian University Librarians (CAUL) database. Eleven (31%) responses qualified for analysis. Of the respondents, the findings include 92% hold tangible special collections as part of their university library collection; 90% do not have a specific plan for the protection of special collections and 90% have experienced a disaster event at some point in their library career. The research concludes that special collections held by Australian universities are at risk and that the role of the university librarian is undervalued in the global efforts to protect cultural and historical heritage in the event of a disaster.

Ordered ensembles of atoms, such as atomic arrays, exhibit distinctive features from their disordered counterpart. In particular, while collective modes in disordered ensembles show a linear optical response, collective subradiant excitations of subwavelength arrays are endowed with an intrinsic non-linearity. Such non-linearity has both a coherent and a dissipative component: two excitations propagating in the array scatter off each other leading to formation of correlations and to emission into free space modes. We show how to take advantage of such non-linearity to coherently prepare a single excitation in a subradiant (dark) collective state of a one dimensional array as well as to perform an entangling operation on dark states of parallel arrays. We discuss the main source of errors represented by disorder introduced by atomic center-of-mass fluctuations, and we propose a practical way to mitigate its effects., Comment: We corrected several typos present in the published version. We thank Lukas Wangler for bringing many typos to our attention. 12+13 pages, 7+6 figures

We introduce and demonstrate a scheme for eliminating the inhomogeneous dephasing of a collective quantum state. The scheme employs off-resonant fields that continuously dress the collective state with an auxiliary sensor state, which has an enhanced and opposite sensitivity to the same source of inhomogeneity. We derive the optimal conditions under which the dressed state is fully protected from dephasing, when using either one or two dressing fields. The latter provides better protection, circumvents qubit phase rotation, and suppresses the sensitivity to drive noise. We further derive expressions for all residual, higher-order, sensitivities. We experimentally study the scheme by protecting a collective excitation of an atomic ensemble, where inhomogeneous dephasing originates from thermal motion. Using photon storage and retrieval, we demonstrate complete suppression of inhomogeneous dephasing and consequently a prolonged memory time. Our scheme may be applied to eliminate motional dephasing in other systems, improving the performance of quantum gates and memories with neutral atoms. It is also generally applicable to various gas, solid, and engineered systems, where sensitivity to variations in time, space, or other domains limits possible scale-up of the system., Revision includes extraction of the inhomogeneous dephasing time for various dressing parameters, discusses several extensions to other systems and applications, and clarifies further differences from previous schemes ;15 pages (including Methods and Supplementary information),6 figures, 1 table

The compatibility of cavity-generated spin-squeezed atomic states with atom-interferometric sensors that require freely falling atoms is demonstrated. An ensemble of $500,000$ spin-squeezed atoms in a high-finesse optical cavity with near-uniform atom-cavity coupling is prepared, released into free space, recaptured in the cavity, and probed. Up to $\sim$10 dB of metrologically-relevant squeezing is retrieved for 700 microsecond free-fall times, and decaying levels of squeezing are realized for up to 3 millisecond free-fall times. The degradation of squeezing results from loss of atom-cavity coupling homogeneity between the initial squeezed state generation and final collective state read-out. A theoretical model is developed to quantify this degradation and this model is experimentally validated.

Aydın, Sezgin ( Aksaray, Yazar ), Level structures of Rn212 have been studied by in-beam γ-ray spectroscopic methods using the Bi209(Li6,3n)Rn212 reaction at beam energies of 28, 30, and 34 MeV. A number of new nonyrast states based on πh9/24 and πh9/23f7/2 configurations have been identified. A 3(-) collective state is also proposed at 2121 keV, which is most likely formed by mixing the octupole vibration with the 3- member of the πh9/23i13/2 multiplet. The level scheme is compared with large-scale shell model calculations and discussed in terms of excitations of valence protons and without contributions from the Pb208 core. An overall excellent agreement is obtained for states that can be described in this model space.

Janus oscillators have been recently introduced as a remarkably simple phase oscillator model that exhibits nontrivial dynamical patterns-such as chimeras, explosive transitions, and asymmetry-induced synchronization-that were once observed only in specifically tailored models. Here we study ensembles of Janus oscillators coupled on large homogeneous and heterogeneous networks. By virtue of the Ott-Antonsen reduction scheme, we find that the rich dynamics of Janus oscillators persists in the thermodynamic limit of random regular, Erdos-Renyi, and scale-free random networks. We uncover for all these networks the coexistence between partially synchronized states and a multitude of solutions of a collective state we denominate as a breathing standing wave, which displays global oscillations. Furthermore, abrupt transitions of the global and local order parameters are observed for all topologies considered. Interestingly, only for scale-free networks, it is found that states displaying global oscillations vanish in the thermodynamic limit.

This conceptual paper stems from a growing body of research examining the roles and functions of emotional climate (EC)—the collective state of students’ shared emotions—in classrooms. It suggests that EC in classrooms can be analyzed as a synchronization phenomenon. Synchronization is a natural phenomenon, in which autonomous objects that produce periodic rhythms adjust these rhythms to one another. The purpose of this article is thus twofold: to position the concept of EC within the broader context of synchronization theory; and to propose a new definition for EC that captures synchronization aspects. This paper first explains the theory of synchronization. It then critically discusses several sociological and biological theories regarding emotions, and the implications of these theories for teaching and learning. It subsequently delves into current conceptualizations of EC, and the descriptors used to characterize EC in classrooms. On the backdrop of this theoretical review, an argument is developed that humans’ produced emotions can be viewed as autonomous rhythmic oscillators that have the capacity to synchronize with one another, and that, consequently, EC can be studied as a form of synchronization within an ensemble of oscillators. Finally, a new definition of EC is proposed that integrates essential synchronization features. Overall, this paper suggests that synchronization theory can provide a framework of analysis of EC as a holistic phenomenon, not reduced to discrete emotional events. This approach may contribute to enhancing explanatory and predictive capacities in the study of EC.

Excitation of long-lived triplet magnetoexcitons in a Hall insulator (filling factor ν = 2) with a high mobility of electrons, at low temperatures, Т < 1 K, enabled to discover a new collective state − magnetofermionic condensate, that interacts coherently with an external electromagnetic field, exhibits superradiant properties and, owing to its low viscosity, spreads over the surface of the two-dimensional structure for macroscopically large distances.

The study objective was to analyze scholars’ and publicists’ views of the Soviet era on the development of the collective-state farming system during two decades after World War II. The key aims were to reveal the influence of ideological and political attitudes of the supreme authority on researchers’ opinion, similarities and differences in the views of historians, economists and publicists regarding the issues. Collective farm peasant problematics have dominated scientific literature. The works of economists of the 1960–1980s have highly assessed «destalinization» of the collective farming system of the mid-1950s and substantiated the necessity of using cooperative starters and market mechanisms on farms. Historians in their fundamental works on this subject published in the second half of the 1980s have cautiously evaluated the agrarian “destalinization” by N. S. Khruschev and paid tribute to the Stalinist strategy of collective farming. State farming issues became popular due to large-scale construction of state farms developed under the guidance of N. S. Khruschev in the second half of the 1950s. During the period of his leadership (1953–1964), researchers gave this undertaking a high appraisal, however after 1964 critical judgments started appearing in the works of scientists, primarily regarding the policy of transforming collective farms into state ones. During the years of Perestroika, the attitude of scholars and publicists towards the Soviet system became more critical from the supreme power. There was an opinion that the collective-state farming system was never and would not be an effective economic mechanism due to incurable «generational traumas» of past experiences. Opponents of this opinion argued that it lost its fundamental shortcomings in the post-Stalin period, and continued to have a future.

In this Letter, we give a new, to the best of our knowledge, perspective on the origin of light coherence in lasers. We demonstrate that a coherence appears below the lasing threshold and manifests itself as long-range correlations between polarizations of active medium atoms. These correlations contribute to the formation of a collective state of atomic polarizations and electromagnetic field modes, which interacts more effectively with the active medium and lases when pumping exceeds the lasing threshold. We demonstrate that inhibiting these atomic correlations leads to the destruction of the collective state and suppression of lasing. The obtained results open up new ways to control coherence.

In 2006, the government of Morocco decided to privatize the land of the former socialist-inspired collective state cooperatives, which had been created in the early 1970s. The resulting shift in land control is happening alongside – but is also provoking – wider processes of agrarian change, manifested among others things in land sells, the introduction of new high-value crops, the use of new technologies (tubewells and drip irrigation), and alterations in labour relations. These transformations influence the development of family farming and gender relations. On the basis of an ethnographic and historical study conducted in a dissolving state cooperative in the agricultural plain of the Saiss we suggest opening the “black box” of the family farm to illustrate the gender dynamics that mark the impact of current agrarian dynamics today. Through this lens we first of all illustrate how during the period of the state cooperative the land, the farms, and the families were deeply intertwined through labour relations and by how the land was used, forming the identities of peasant women and men. By retracing the development of various peasant families we illustrate how this farming model is changing today. The current agrarian dynamics offer new possibilities of being and becoming to some young men and “modern” farmers. Nevertheless, various peasant women increasingly find less pride in their agricultural work and actively seek to develop new rural feminine identities, which is not easy. As such, we observe how the future becoming of peasant farming will strongly depend on the next generation of farmers and of their aspiration of modernizing their future becoming.L’Etat marocain decida en 2006 de privatiser les terres des cooperatives de la reforme agraire creee au debut des annees 1970. Cette dynamique fonciere s’inscrit dans des processus plus larges de changements agraires, qui se manifeste entre autre par la vente des terres, l’introduction de nouvelles cultures a forte valeur ajoutee, l’utilisation de nouvelles technologies (forage et goutte-a-goutte) et des transformations dans les relations de travail. Ces changements auront une influence sur le developpement de l’agriculture familiale et les relations de genres. A la base d’un travail ethnographique et historique portant sur une cooperative dans la plaine du Saiss, nous suggerons d’ouvrir la « boite noire » de l’agriculture familiale pour illustrer les dynamiques de genre qui marquent aujourd’hui l’impact des changements agraires. A travers ce regard nous illustrons dans un premier temps comment, pendant la periode de la cooperative la terre, l’exploitation et la famille paysanne etaient intimement liees. Les activites et l’organisation autour de la terre forment les identites des hommes et des femmes paysans. Aujourd’hui, nous illustrons au travers de differentes trajectoires de familles paysannes comment ce modele est en mutation. Les dynamiques agraires offrent de nouvelles opportunites a certains jeunes hommes et agriculteurs « modernes ». Cependant, differentes femmes paysannes ne trouvent plus de fierte dans le travail agricole et essaient de developper de nouvelles identites feminines rurales, ce qui n’est pas facile. Ainsi, nous verrons que le devenir de l’agriculture paysanne dependra fortement de cette nouvelle generation de jeunes agriculteurs et agricultrices et de leurs aspirations a moderniser leur devenir.This article is in French.

COVID-19 has thrown community, nation and world into a collective state of grief and mourning. We search for answers as to how this crisis unfolded and question why so many lives were lost. Many of...

This chapter explores themes such as: collective non-recognition in the context of secessionist conflicts, the potential conflict between individual and collective state interests, and the human costs of non-recognition. The chapter first looks at the practice of collective non-recognition, examining the normative, legal and pragmatic reasoning behind it and its effects: what forms of interactions are prohibited in cases of collective non-recognition? It shows that collective non-recognition has not stopped some entities from achieving a condition of de facto statehood, with a broad range of interaction with other states and with international organisations. It will then analyse the implications of the resulting isolation: how does it affect the dynamics of conflict, the significance of patron states and the domestic developments in the resulting unrecognised (or de facto) states? The chapter shows there are variations in the degree of international links available to de facto states that point to inconsistencies in the idea of collective non-recognition, and that collective non-recognition does not always promote conflict resolution.

This research is the result of a collaboration established between ergonomists from all over the world that are concerned with education of professional ergonomists. We have started a collective state of the art of ergonomics training programs for professionals, according to IEA standards. The team that organizes this symposium has already started this research and published it at 2017 SELF Congress, and continued working in new results from other corners of the world. We have started the project by sending a mail to all the federated societies as they appear in the IEA website, to some of the IEA executive committee members, and finally contacting the ergonomists we know are or were directors of master degrees in ergonomics all over the world. We asked them to give us their feedback through some questions concerning the education program in which the consulted ergonomist has been involved. The stake is to deeply understand the training case through the answers to the questions sent. We got answers from more than 14 countries concerning more than 20 education programs. The panel of the symposium will present the case of 8 programs from different continents. We hope this research will add our “grain of sand” in the necessary collective work of IEA’s “Professional Standards and Education Standing Committee”.

Social intelligence is an emerging property of a system composed of agents that consists of the ability of this system to conceive, design, implement and execute strategies to solve problems and thus achieve a collective state of the system that is concurrently satisfactory for all and each one of the agents that compose it. In order to make decisions when dealing with complex problems related to social systems and take advantage of social intelligence, cooperative games theory constitutes the standard theoretical framework. In the present work, an ontological framework for cooperative games modeling and simulation is presented.

We study chimera states in one-dimensional and two-dimensional Gaussian coupled map lattices through simulations and experiments. Similar to the case of global coupling oscillators, individual lattices can be regarded as being controlled by a common mean field. A space-dependent order parameter is derived from a self-consistency condition in order to represent the collective state.

Estimating collective state is an important component of many distributed systems, but has inherent challenges in balancing the availability of estimates against their accuracy. In this paper, we analyze the error bounds and dynamics of a commonly used family of self-stabilizing state estimation algorithms based on spanning trees. We find that in the worst case transients can duplicate values leading to exponential overestimates or can drop values leading to near total loss of information. The same analysis, however, also suggests that these problems can be mitigated by prioritizing smoothness in the adaptation of distance estimates used to maintain the spanning tree, and this mitigating effect is supported by results in simulation.

The transition from single-cell to multicellular behavior is important in early development but rarely studied. The starvation-induced aggregation of the social amoeba Dictyostelium discoideum into a multicellular slug is known to result from single-cell chemotaxis towards emitted pulses of cyclic adenosine monophosphate (cAMP). However, how exactly do transient, short-range chemical gradients lead to coherent collective movement at a macroscopic scale? Here, we developed a multiscale model verified by quantitative microscopy to describe behaviors ranging widely from chemotaxis and excitability of individual cells to aggregation of thousands of cells. To better understand the mechanism of long-range cell—cell communication and hence aggregation, we analyzed cell—cell correlations, showing evidence of self-organization at the onset of aggregation (as opposed to following a leader cell). Surprisingly, cell collectives, despite their finite size, show features of criticality known from phase transitions in physical systems. By comparing wild-type and mutant cells with impaired aggregation, we found the longest cell—cell communication distance in wild-type cells, suggesting that criticality provides an adaptive advantage and optimally sized aggregates for the dispersal of spores., A multiscale model and imaging data show that cells of the slime mold Dictyostelium discoideum maximize their cell—cell communication range during aggregation by a critical-like state known from phase transitions in physical systems., Author summary Cells are often coupled to each other in cell collectives, such as aggregates during early development, tissues in the developed organism, and tumors in disease. How do cells communicate over macroscopic distances much larger than the typical cell—cell distance to decide how they should behave? Here, we developed a multiscale model of social amoeba, spanning behavior from individuals to thousands of cells. We show that local cell—cell coupling via secreted chemicals may be tuned to a critical value, resulting in emergent long-range communication and heightened sensitivity. Hence, these aggregates are remarkably similar to bacterial biofilms and neuronal networks, all communicating in a pulselike fashion. Similar organizing principles may also aid our understanding of the remarkable robustness in cancer development.

We report on a novel collective state, occurring in globally coupled nonidentical oscillators in the proximity of the point where the transition from the system's incoherent to coherent phase converts from explosive to continuous. In such a state, the oscillators form quantized clusters, where neither their phases nor their instantaneous frequencies are locked. The oscillators' instantaneous speeds are different within the clusters, but they form a characteristic cusped pattern and, more importantly, they behave periodically in time so that their average values are the same. Given its intrinsic specular nature with respect to the recently introduced Chimera states, the phase is termed the Bellerophon state. We provide an analytical and numerical description of Bellerophon states, and furnish practical hints on how to seek them in a variety of experimental and natural systems.

The radiative properties of atomic systems are, in general, much more complicated than those discussed in the previous chapter, in which we considered optical spectra of single multilevel atoms separated by large distances. The complication arises from the fact that in practice atomic separations are small, even in low density atomic beams, and can be of the order of a resonant wavelength.

As one of the most influential experiments on the development of modern macroscopic theory from Newtonian mechanics to Einstein's special theory of relativity, the phenomenon of light dragging in a moving medium has been discussed and observed extensively in different types of systems. To have a significant dragging effect, the long duration of light travelling in the medium is preferred. Here we demonstrate a light-dragging experiment in an electromagnetically induced transparent cold atomic ensemble and enhance the dragging effect by at least three orders of magnitude compared with the previous experiments. With a large enhancement of the dragging effect, we realize an atom-based velocimeter that has a sensitivity two orders of magnitude higher than the velocity width of the atomic medium used. Such a demonstration could pave the way for motional sensing using the collective state of atoms in a room temperature vapour cell or solid state material., Phase velocity of light can be slowed down when passing through a moving medium. Here the authors demonstrate a light dragging effect enhanced by three orders of magnitude over previous reports by using electromagnetically induced transparency in cold Rubidium atoms and utilize this effect for motion sensors.

Recent experiments with suspended graphene have indicated the crucial role of carrier mobility in the competition between Laughlin collective state and insulating state, probably of Wigner-crystal-type. Moreover, the fractional quantum Hall effect (FQHE) in graphene has been observed at a low carrier density where the interaction is reduced as a result of particles dilution. This suggests that the interaction may not be a sole factor in the triggering of FQHE as it was expected basing on the standard formulation of the composite fermion model. Here, the topological arguments are presented to explain the observed features of the FQHE in graphene and the triggering role of carrier mobility in formation of the Laughlin state.