Explicit Coordination Research Articles

Topological Structure Determination of RNA Using Small-Angle X-Ray Scattering

Knowledge of RNA three-dimensional topological structures provides important insight into the relationship between RNA structural components and function. It is often likely that near-complete sets of biochemical and biophysical data containing structural restraints are not available, but one still wants to obtain knowledge about approximate topological folding of RNA. In this regard, general methods for determining such topological structures with minimum readily available restraints are lacking. Naked RNAs are difficult to crystallize and NMR spectroscopy is generally limited to small RNA fragments. By nature, sequence determines structure and all interactions that drive folding are self-contained within sequence. Nevertheless, there is little apparent correlation between primary sequences and three-dimensional folding unless supplemented with experimental or phylogenetic data. Thus, there is an acute need for a robust high-throughput method that can rapidly determine topological structures of RNAs guided by some experimental data. We present here a novel method (RS3D) that can assimilate the RNA secondary structure information, small-angle X-ray scattering data, and any readily available tertiary contact information to determine the topological fold of RNA. Conformations are firstly sampled at glob level where each glob represents a nucleotide. Best-ranked glob models can be further refined against solvent accessibility data, if available, and then converted to explicit all-atom coordinates for refinement against SAXS data using the Xplor-NIH program. RS3D is widely applicable to a variety of RNA folding architectures currently present in the structure database. Furthermore, we demonstrate applicability and feasibility of the program to derive low-resolution topological structures of relatively large multi-domain RNAs.

Only distances are required to reconstruct submanifolds

In this paper, we give the first algorithm that outputs a faithful reconstruction of a submanifold of Euclidean space without maintaining or even constructing complicated data structures such as Voronoi diagrams or Delaunay complexes. Our algorithm uses the witness complex and relies on the stability of power protection, a notion introduced in this paper. The complexity of the algorithm depends exponentially on the intrinsic dimension of the manifold, rather than the dimension of ambient space, and linearly on the dimension of the ambient space. Another interesting feature of this work is that no explicit coordinates of the points in the point sample is needed. The algorithm only needs the distance matrix as input, i.e., only distance between points in the point sample as input.

Antitrust for Institutional Investors

With the increasing concentration of shares in the hands of large institutional investors, combined with greater involvement in corporate governance, the antitrust risk of common ownership has moved to center stage. Through an excess of enthusiasm, portfolio managers could end up exposing their firms and the portfolio companies to huge antitrust liability. In this Article, we start from basic antitrust principles to sketch out an antitrust compliance program for institutional investors and for the investor relations groups in portfolio companies. In doing so, we address the fundamental antitrust issues (explicit and tacit coordination) raised by the presence of common ownership by large, diversified investors. We then turn to more speculative concerns that have garnered a great deal of attention and that, to our eyes, threaten to divert attention from the core antitrust issues. We critically examine the claims of this newer literature, as illustrated by Azar, Schmaltz and Tecu (2017), that existing ownership patterns in the airline industry results in substantially higher prices. We then turn to the argument in Elhauge (2016) that existing ownership patterns violate Section 7 of the Clayton Act. Finally, we find the policy recommendations of Posner, Scott Morton, and Weyl (2017) to limit the ownership shares of multiple firms in oligopolistic industries to be overly stringent. To limit the chilling effect of antitrust on the valuable role of institutional investors in corporate governance, we propose a quasi “safe harbor” that protects investors from antitrust liability when their ownership share is less than 15 percent, the investors have no board representation, and they only engage in “normal” corporate governance activities.

Provider Connectedness to Other Providers Reduces Risk of Readmission After Hospitalization for Heart Failure.

Provider interactions other than explicit care coordination, which is challenging to measure, may influence practice and outcomes. We performed a network analysis using claims data from a commercial payor. Networks were identified based on provider pairs billing outpatient care for the same patient. We compared network variables among patients who had and did not have a 30-day readmission after hospitalization for heart failure. After adjusting for comorbidities, high median provider connectedness-normalized degree, which for each provider is the number of connections to other providers normalized to the number of providers in the region-was the network variable associated with reduced odds of readmission after heart failure hospitalization (odds ratio = 0.55; 95% confidence interval [0.35, 0.86]). We conclude that heart failure patients with high provider connectedness are less likely to require readmission. The structure and importance of provider relationships using claims data merits further study.

Explicit and implicit team coordination: Development of a multidimensional scale

We reviewed team coordination and implicit coordination theories and developed an explicit and implicit team coordination scale. After item revision of a preliminary scale had been performed by 5 experts, there were 30 items in 6 dimensions classified as explicit accountability, explicit predictability, explicit common understanding, implicit accountability, implicit predictability, and implicit common understanding. The reliability and validity of these items were determined with 323 participants, after which exploratory factor analysis resulted in 5 valid dimensions: explicit accountability, implicit accountability, explicit predictability, implicit predictability, and common understanding, comprising 26 items in the multidimensional scale. Future researchers can further explore the applicability of the scale for measuring team coordination in team management practices.

Important Non-Technical Skills in Video-Assisted Thoracoscopic Surgery Lobectomy: Team Perspectives

Safety in the operating room is dependent on the team's non-technical skills. The importance of non-technical skills appears to be different for minimally invasive surgery as compared with open surgery. The aim of this study was to identify which non-technical skills are perceived by team members to be most important for patient safety, in the setting of video-assisted thoracoscopic surgery (VATS) lobectomy. This was an explorative, semistructured interview-based study with 21 participants from all four thoracic surgery centers in Denmark that perform VATS lobectomy. Data analysis was deductive, and directed content analysis was used to code the text into the Oxford Non-Technical Skills system for evaluating operating teams' non-technical skills. The most important non-technical skills described by the VATS teams were planning and preparation, situation awareness, problem solving, leadership, risk assessment, and teamwork. These non-technical skills enabled the team to achieve shared mental models, which in turn facilitated their efforts to anticipate next steps. This was viewed as important by the participants as they saw VATS lobectomy as a high-risk procedure with complementary and overlapping scopes of practice between surgical and anesthesia subteams. This study identified six non-technical skills that serve as the foundation for shared mental models of the patient, the current situation, and team resources. These findings contribute three important additions to the shared mental model construct: planning and preparation, risk assessment, and leadership. Shared mental models are crucial for patient safety because theyenable VATS teams to anticipate problems throughadaptive patterns of both implicit and explicit coordination.

Topological structure determination of RNA using small-angle X-ray scattering

Knowledge of RNA three-dimensional topological structures provides important insight into the relationship between RNA structural components and function. It is often likely that near-complete sets of biochemical and biophysical data containing structural restraints are not available, but one still wants to obtain knowledge about approximate topological folding of RNA. In this regard, general methods for determining such topological structures with minimum readily available restraints are lacking. Naked RNAs are difficult to crystallize and NMR spectroscopy is generally limited to small RNA fragments. By nature, sequence determines structure and all interactions that drive folding are self-contained within sequence. Nevertheless, there is little apparent correlation between primary sequences and three-dimensional folding unless supplemented with experimental or phylogenetic data. Thus, there is an acute need for a robust high-throughput method that can rapidly determine topological structures of RNAs guided by some experimental data. We present here a novel method (RS3D) that can assimilate the RNA secondary structure information, small-angle X-ray scattering data, and any readily available tertiary contact information to determine the topological fold of RNA. Conformations are firstly sampled at glob level where each glob represents a nucleotide. Best-ranked glob models can be further refined against solvent accessibility data, if available, and then converted to explicit all-atom coordinates for refinement against SAXS data using the Xplor-NIH program. RS3D is widely applicable to a variety of RNA folding architectures currently present in the structure database. Furthermore, we demonstrate applicability and feasibility of the program to derive low-resolution topological structures of relatively large multi-domain RNAs.

Translator behaviour and language usage: some constraints on contrastive studies

This article concerns the phenomenon of junction, a cohesive device for signalling inter-clausal or inter-sentential relations, and its translation. The predominant finding of recent French-English contrastive studies on the topic of junction has been that, whereas there is a trend to junction-less juxtaposition in French, explicit co-ordination is preferred in English. Doubts concerning the universal validity of such a norm constitute the motivation for this study, which aims to consider:(1) the status of translator behaviour as evidence of norms of language behaviour;(2) the status of contrastive linguistics within translation studies.Examples of translations of writings by Albert Camus are then discussed in an attempt to show that translators’ decisions are sensitive to a number of contextual factors including genre, discourse and text type. My conclusions lead me to suggest some limitations on the use of quantitative studies within translation studies, including those based on analysis of machine-readable corpora.

The Hamiltonian tube of a cotangent-lifted action

The Marle-Guillemin-Sternberg (MGS) form is local model for a neighborhood of an orbit of a Hamiltonian Lie group action on a symplectic manifold. One of the main features of the MGS form is that it puts simultaneously in normal form the existing symplectic structure and momentum map. The main drawback of the MGS form is that it does not have an explicit expression. We will obtain a MGS form for cotangent-lifted actions on cotangent bundles that, in addition to its defining features, respects the additional fibered structure present. This model generalizes previous results obtained by T. Schmah for orbits with fully-isotropic momentum. In addition, our construction is explicit up to the integration of a differential equation on G. This equation can be easily solved for the groups SO(3) or SL(2), thus giving explicit symplectic coordinates for arbitrary canonical actions of these groups on any cotangent bundle.

Coordinated Implicitly? An Empirical Study on the Role of Social Media in Collaborative Learning

<p class="3">As social media is widely adopted in collaborative learning, which places teams in a virtual environment, it is critical for teams to identify and leverage the knowledge of their members. Yet little is known about how social media influences teams to coordinate their knowledge and collaborate effectively. In this research, we explore the roles of two kinds of social media activity – information processing and social connection in teamwork – by applying communication and transactive memory systems (TMSs) as the mechanisms of explicit and implicit coordination respectively. We test this model using partial least squares (PLS) method by treating team as the unit of analysis. Drawing on the data from a study that involves 40 teams of graduate students performing a complex research report over eight weeks, we find that both TMSs and communication can significantly improve teamwork outcomes, and communication can help teams to better coordinate implicitly. With regard to social media activities, the results reveal that both information processing and social connection can enhance the level of TMSs; however, only social connection is positively related to communication. Unfortunately, information processing cannot significantly strengthen communication quality. The possible reasons are discussed and some theoretical and practical implications are also put forward.</p>

Power coordinates

We present a full geometric parameterization of generalized barycentric coordinates on convex polytopes. We show that these continuous and non-negative coefficients ensuring linear precision can be efficiently and exactly computed through a power diagram of the polytope's vertices and the evaluation point. In particular, we point out that well-known explicit coordinates such as Wachspress, Discrete Harmonic, Voronoi, or Mean Value correspond to simple choices of power weights. We also present examples of new barycentric coordinates, and discuss possible extensions such as power coordinates for non-convex polygons and smooth shapes.

Coordination of Cooperative Autonomous Vehicles: Toward safer and more efficient road transportation

While intelligent transportation systems come in many shapes and sizes, arguably the most transformational realization will be the autonomous vehicle. As such vehicles become commercially available in the coming years, first on dedicated roads and under specific conditions, and later on all public roads at all times, a phase transition will occur. Once a sufficient number of autonomous vehicles is deployed, the opportunity for explicit coordination appears. This article treats this challenging network control problem, which lies at the intersection of control theory, signal processing, and wireless communication. We provide an overview of the state of the art, while at the same time highlighting key research directions for the coming decades.

Improving geolocation of social media posts

Pervasive social systems often take advantage of geographical information to provide real-time information to users based on their location. However, due to privacy concerns, many social media users do not share their exact geographical coordinates. In this paper, we describe our technique that predicts locations of posts that are not associated with explicit coordinates, a process called geolocation. Existing research has utilized the content of a post as well as the post author’s social media relationships with other users to estimate location. Our research provides a novel approach to geolocation by combining multiple techniques, as well as adding a new technique: estimating location by clustering similar social media posts that are centered in a geographical area.

The catalytic role of the water or acidic zeolite in the oxidation of BrCH2OH. A theoretical study

We present a computational investigation of the catalytic activity of the water molecules or acidic zeolite in the oxidation of bromomethanol, coming from the degradation of brominated organic compounds in the natural environment. The role of the water in this mechanism has been established using MP2(full)/6-311++G(3df, 2p) level of theory. Energetic results were further refined by CCSD(T) calculations, using optimized geometric parameters of the MP2 level. The computational investigation shows clearly the dramatic reduction of the activation energy of the oxidation to formaldehyde that occurs when explicit coordination of water molecules is taken into account. Further investigation of the degradation mechanism has been carried out by considering the oxidation reaction as taking place on acidic zeolite surface, with the help of the hybrid (QM/MM) approximation and specifically the two-layered, ONIOM2 methodology at the (MP2(full)/6-31G∗:UFF) and (M06-2X/6-311++G(3df, 2p):UFF) levels of theory.

A computational investigation of polypyrrolic macrocyclic actinyl complexes: effects of explicit solvent coordination on structure, vibrational spectra and redox property

Eighteen actinyl complexes of a Schiff-base polypyrrolic macrocycle (H4L), [(Sol)(AnmO2)(H2L)]n− (Sol = Vacant, pyridine (py) and tetrahydrofuran (THF); An=U, Np and Pu; m = VI and n = 0, m = V and n = 1) were investigated using relativistic density functional theory. Comparison of complexes with and without the explicit solvent coordination to the metal center, and changes in actinide element and metal oxidation state provide insight into their effects on structural and energetic properties of the complexes. Compared with those of the solvent-free complexes, the An=O bond lengths of the solvated complexes differ within 0.01 A, and the deviation of the O=An=O angles is less than 1°. The H···Oendo bonds are relatively sensitive to the explicit solvent coordination, showing the largest discrepancy of 0.05 A. Charges and electron-spin densities of actinides are only slightly affected by the inclusion of the explicit solvent. Reduction potentials of actinyl complexes have been addressed, and their dependence on the bulk solvent polarity is being discussed, using a simple model based on the Born equation.

The Promise and Pitfalls of Assembled Institutions: Lessons from the Global Environment Facility and UNAIDS

AbstractContemporary global governance architecture has been described as fragmented, incoherent, and inefficient. The mandates of prominent international organizations (IOs) often overlap and coordination is regarded more as the exception than the rule. In this context, international institutions designed with an explicit coordination mandate hold significant promise. These assembled institutions (AIs), like the Global Environment Facility (GEF) and UNAIDS, formally incorporate IOs in their designs and seek to coordinate and bring coherence to their work in a given issue area. Although praised for their bold and innovative designs, little scholarly work has assessed the success of these institutions in fulfilling coordination mandates. The paper introduces AIs as an organizational form and sheds light on two challenges they face that provide barriers to coordination. First, concerns regarding status and material losses may cause relevant IOs to resist coordination despite ostensibly opting in to participate in the assembled institution. Second, the governing bodies of assembled institutions are weak relative to the prominent IOs incorporated in their designs. The home governing bodies of these institutions often do little to reinforce the importance of coordination, hampering performance. These challenges are illustrated in the case of the GEF and UNAIDS.

Making conceptual connections visible to students in professional programmes: The case of initial teacher education

This paper presents a comparative analysis of education courses offered across five South African universities participating in the Initial Teacher Education Research Project. The analysis compares knowledge selected for compulsory education modules that are taken by all student teachers regardless of their subject / phase specializations. All programmes include modules that examine curriculum knowledge, learners, pedagogy and context as objects of study in their own right. However, these objects are studied through different practical and/or theoretical lenses. The extent to which each object is brought into relation with others is also variable and programme design structures suggest that these relationships will be explored in specialization courses. However, it should not be presumed that this will happen without explicit collaboration and coordination. It is recommended that the relations between the elements need explicitly to be designed into the compulsory courses, subject/phase specific pedagogy courses and in the design of the practicum.

Peptide Hydration Phenomena through a Combined Quantum Chemical and Bottom-Up Approach

Abstract The M06-2X, TPSS, and B3PW91 density functionals and the classical ab initio MP2 method were used to study microsolvation around the protonated trialanine, Ala3H+. All adopted electronic structure approaches show the formation of wires or compact ring clusters of water molecules strongly bonded to peptidic polar groups through hydrogen bonds with hydration energy ranging from − 93 to –66 kcal mol –1. Independently from the adopted electronic structure methods, explicit water molecules favor peptidic chain with the polyproline II (PPII) conformation, thus the electronic energy stability order of the four unfolded conformers follows the sequence: PPII-PPII > β-PPII ∼ PPII-β > β-β, while entropy favors the reversed order. The delicate balance of electronic energy (or enthalpy) and entropy modulated by the temperature accounts for the change in abundance of the PPII and β conformations experimentally observed. The proposed bottom-up approach has been developed following the energetically dominant polar groups of peptide and water dipoles interactions. The intrapeptide dipole decoupling, caused by the β → PPII transformation, and the consequent greater dipole coupling with water molecules provide a rational base to explain the energy gain due to the explicit water coordination to PPII residues.

Opportunistic Channel Selection by Cognitive Wireless Nodes Under Imperfect Observations and Limited Memory: A Repeated Game Model

We study the problem of how autonomous cognitive nodes (CNs) can arrive at an efficient and fair opportunistic channel access policy in scenarios where channels may be non-homogeneous in terms of primary user (PU) occupancy. In our model, a CN that is able to adapt to the environment is limited in two ways. First, CNs have imperfect observations (such as due to sensing and channel errors) of their environment. Second, CNs have imperfect memory due to limitations in computational capabilities. For efficient opportunistic channel access, we propose a simple adaptive win-shift lose-randomize (WSLR) strategy that can be executed by a two-state machine (automaton). Using the framework of repeated games (with imperfect observations and limited memory), we show that the proposed strategy enables the CNs (without any explicit coordination) to reach an outcome that: 1) maximizes the total network payoff and also ensures fairness among the CNs; 2) reduces the likelihood of collisions among CNs; and 3) requires a small number of sensing steps (attempts) to find a channel free of PU activity. We compare the performance of the proposed autonomous strategy with a centralized strategy and also test it with real spectrum data collected at RWTH Aachen.

Coordinated Selfish Distributed Caching for Peering Content-Centric Networks

A future content-centric Internet would likely consist of autonomous systems (ASes) just like today’s Internet. It would thus be a network of interacting cache networks, each of them optimized for local performance. To understand the influence of interactions between autonomous cache networks, in this paper, we consider ASes that maintain peering agreements with each other for mutual benefit and engage in content-level peering to leverage each others’ cache contents. We propose a model of the interaction between the caches managed by peering ASes. We address whether stable and efficient content-level peering can be implemented without explicit coordination between the neighboring ASes. We show that content-level peering leads to stable cache configurations, both with and without coordination. However, peering Internet Service Providers (ISPs) that coordinate to avoid simultaneous updates converge to a stable configuration more efficiently. Furthermore, if the content popularity estimates are inaccurate, content-level peering is likely to lead to cost efficient cache allocations. We validate our analytical results using simulations on the measured peering topology of more than 600 ASes.