cssi/SciSciGPT-SciSciNet huggingface dataset:
Separation of diffracted waves in transversely isotropic media

Imaging diffracted waves can provide useful information about complex subsurface geology and fracture networks. Separation of diffractions from typically more intensive reflected events can be done based on specularity, which measures deviation from Snell’s law. Here, we analyze two formulations of specularity and their applicability to diffraction processing in the presence of anisotropy. We show that the most common definition of specularity, originally introduced for pure modes in isotropic media, remains valid for both pure and converted waves in arbitrarily anisotropic models. The other formulation operates directly with the difference between the slowness projections onto the reflector for the incident and reflected waves. Testing on a VTI (transversely isotropic with a vertical symmetry axis) diffraction ramp model demonstrates that both formulations produce satisfactory results for anisotropic media with appropriate tapering of the specularity gathers. Then separation and imaging of diffractions is performed for the structurally complex VTI Marmousi model. We also analyze the sensitivity of diffractions in the specularity gathers to errors in the symmetry-direction velocity and anellipticity parameter η.
Efficient Metropolitan Resource Allocation

Over the past 30 years Calgary has doubled in size, from a population of 640,645 in 1985 to 1,230,915 in 2015. During that time the City has had five different mayors, hosted the Winter Olympics, and expanded the C-Train from 25 platforms to 45. Calgary’s Metropolitan Area has grown too, with Airdrie, Chestermere, Okotoks and Cochrane growing into full-fledged cities, ripe with inter-urban commuters.* And with changes to provincial legislation in the mid-’90s, rural Rocky View County and the Municipal District of Foothills are now real competitors for residential, commercial and industrial development that in the past would have been considered urban. In this metropolitan system, where people live, their household structure, and their place of work informs the services they need to conduct their daily lives, and directly impacts the spatial character of the City and the broader region. In sum, Metropolitan Calgary is increasingly complex. Calgary and the broader metropolitan area will continue to grow, even with the current economic slowdown. Frictions within Calgary, between the various municipalities in the metropolitan area, and the priorities of other local authorities (such as the School Boards and Alberta Health Services) will continue to impact the agendas of local politicians and their ability to answer to the needs of their residents. How resources – whether it is hard infrastructure, affordable housing, classrooms, or hospital beds – are allocated over space and how these resources are funded, directly impacts these relationships. This technical paper provides my perspective as an urban economist on the efficient allocation of resources within a metropolitan system in general, with reference to Calgary where appropriate, and serves as a companion to the previously released “Reflections on Calgary’s Spatial Structure: An Urban Economists Critique of Municipal Planning in Calgary.” It is hoped that the concepts reviewed herein effectively expand upon and supplement the discussion in the former paper. The urban economic perspective adopted in this paper is itself not inconsistent with the public economics perspective but it pays more attention to space, and metropolitan transportation and land use policy, and less to tax policy and intergovernmental fiscal arrangements. I will explore the following sources of inefficiency within a metropolitan system: 1) local public goods, 2) externalities, and 3) economies of scale, starting with a short background on classic market failure and second-best policy.
Arterial stiffness and its relationship to clinic and ambulatory blood pressure: a longitudinal study in non-dialysis chronic kidney disease.

Background Both arterial stiffness and systolic blood pressure (BP) are established cardiovascular risk factors, yet little is known about their interrelationship in chronic kidney disease (CKD). The goal of this prospective study was to describe the trajectory of aortic pulse wave velocity (PWV) and BP and to compare the longitudinal interrelationship of BP (clinic and 24 h ambulatory recording) with the PWV. Methods Clinic BP was taken in two ways: at the time of the measurement of the PWV (Clinic-S) and as an average of triplicate measurements on three separate occasions within 1 week (Clinic-M). 24 h ambulatory BP was measured using a validated monitor and PWV was measured in the aorta using an echo-Doppler technique. Results Among 255 veterans with CKD followed for over up to 4 years, the rate of change of log PWV was inversely related to the baseline PWV; the trajectories were variable among individuals and the net population change was no different from zero. In contrast, systolic BP significantly increased, but linearly, and a strong relationship was seen between cross-sectional and longitudinal changes in Clinic-M systolic BP and log PWV. In contrast, a longitudinal relationship between Clinic-S and log PWV was absent. In the case of 24-h ambulatory BP, a strong cross-sectional change was seen between awake and 24 h systolic BP but not between sleep BP and log PWV. Conclusion In conclusion, among people with CKD, the PWV changes over time and is inversely related to the baseline PWV. An average of clinic BP measurements taken over three visits, but not single measurements, are useful to assess the PWV and its change over time. Differences exist between ambulatory BP monitoring recording during the sleep and awake states in their ability to predict the PWV. Taken together, these data support the view that among those with CKD not on dialysis, targeting clinic BP taken on multiple occasions using a standardized methodology or daytime ambulatory systolic BP may slow the progression of arterial damage.
Charge diffusion and the butterfly effect in striped holographic matter

Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength “hydrodynamic” disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.
Shifts in the Fecal Microbiota Associated with Adenomatous Polyps.

Background: Adenomatous polyps are the most common precursor to colorectal cancer, the second leading cause of cancer-related death in the United States. We sought to learn more about early events of carcinogenesis by investigating shifts in the gut microbiota of patients with adenomas. Methods: We analyzed 16S rRNA gene sequences from the fecal microbiota of patients with adenomas (n = 233) and without (n = 547). Results: Multiple taxa were significantly more abundant in patients with adenomas, including Bilophila, Desulfovibrio, proinflammatory bacteria in the genus Mogibacterium, and multiple Bacteroidetes species. Patients without adenomas had greater abundances of Veillonella, Firmicutes (Order Clostridia), and Actinobacteria (family Bifidobacteriales). Our findings were consistent with previously reported shifts in the gut microbiota of colorectal cancer patients. Importantly, the altered adenoma profile is predicted to increase primary and secondary bile acid production, as well as starch, sucrose, lipid, and phenylpropanoid metabolism. Conclusions: These data hint that increased sugar, protein, and lipid metabolism along with increased bile acid production could promote a colonic environment that supports the growth of bile-tolerant microbes such as Bilophilia and Desulfovibrio. In turn, these microbes may produce genotoxic or inflammatory metabolites such as H2S and secondary bile acids, which could play a role in catalyzing adenoma development and eventually colorectal cancer. Impact: This study suggests a plausible biological mechanism to explain the links between shifts in the microbiota and colorectal cancer. This represents a first step toward resolving the complex interactions that shape the adenoma–carcinoma sequence of colorectal cancer and may facilitate personalized therapeutics focused on the microbiota. Cancer Epidemiol Biomarkers Prev; 26(1); 85–94. ©2016 AACR.
The Proliferation of Disputes, Dispute Settlement Procedures and Respect for the Rule of Law

IT IS truly a great pleasure for me to be here with you this evening. I must admit, however, that I feel a little bit like the lawyer who comes home late one evening totally drunk. His wife meets him at the door and screams, ‘what have you to say for yourself?’ He looks at her in total innocence and mumbles: ‘I don't really have anything to say, but I would be pleased to entertain questions’. Unlike the lawyer in this story, I attribute my problem not to alcohol but to the topic assigned to me, ‘The proliferation of disputes, dispute settlement procedures and respect for the rule of law’. Your colloquium organisers very kindly gave me this broad topic to allow me to speak about anything I wanted to, and for that I am most grateful. But, of course, this broad topic creates its own problem: what specifically to speak about. Clearly, we have been witnessing a proliferation of disputes as well as a proliferation of dispute settlement procedures. I doubt, though, that respect for the rule of law has kept up with the proliferation of disputes and dispute settlement procedures, and I will have something to say on this subject in a moment, but let me first say a word about the proliferation of disputes and dispute settlement mechanisms. A story frequently told in American law schools runs something like this: a young lawyer moves into a small town that has not had a local lawyer for some years. The newcomer figures that he will become rich fast since he will get all local legal business. But contrary to his expectations, he is not doing very well and is ready to move to a larger city. But then another lawyer moves into town and both lawyers begin to …
Vocational considerations and trends in Social Security Disability

Abstract Along with health, Social Security Disability Insurance (SSDI) evaluates work-limiting disability by considering vocational factors including age, education, and past work experience. SSDI determinations based on these factors have grown threefold since 1985. We use a unique state-level data-set to estimate how vocational demographics relate to SSDI awards and then assess the contribution of demographic change to SSDI trends. Although workers in their 50s are associated with higher SSDI award rates, secular increases in educational attainment should have offset the impact of population aging on rising SSDI claims, particularly those with vocational considerations.
Testing odd-cycle-freeness in boolean functions

A function f: 2n â {0,1} is odd-cycle-free if there are no x1,.i¾ .i¾ .,xk ∈ 2n with k an odd integer such that f(x1) = i¾·i¾·i¾· = f(xk) = 1 and x1 + i¾·i¾·i¾· + xk = 0. We show that one can distinguish odd-cycle-free functions from those e-far from being odd-cycle-free by making poly(1/e) queries to an evaluation oracle. We give two proofs of this result, each shedding light on a different connection between testability of properties of Boolean functions and of dense graphs. The first issue we study is directly reducing testing of linear-invariant properties of Boolean functions to testing associated graph properties. We show a black-box reduction from testing odd-cycle-freeness to testing bipartiteness of graphs. Such reductions have already been shown (Kral', Serra and Vena, and Shapira) for monotone linear-invariant properties defined by forbidding solutions to a finite number of equations. But for odd-cycle-freeness whose description involves an infinite number of forbidden equations, a reduction to graph property testing was not previously known. If one could show such a reduction more generally for any linear-invariant property closed under restrictions to subspaces, then it would likely lead to a characterization of the one-sided testable linear-invariant properties, an open problem raised by Sudan. The second issue we study is whether there is an efficient canonical tester for linear-invariant properties of Boolean functions. A canonical tester for linear-invariant properties operates by picking a random linear subspace and then checking whether the restriction of the input function to the subspace satisfies a fixed property. The question is if, for every linear-invariant property, there is a canonical tester for which there is only a polynomial blow-up from the optimal query complexity. We answer the question affirmatively for odd-cycle-freeness. The general question remains open.
The ergodic side of the many‐body localization transition

Recent studies point towards nontriviality of the ergodic phase in systems exhibiting many-body localization (MBL), which shows subexponential relaxation of local observables, subdiffusive transport and sublinear spreading of the entanglement entropy. Here we review the dynamical properties of this phase and the available numerically exact and approximate methods for its study. We discuss in which sense this phase could be considered ergodic and present possible phenomenological explanations of its dynamical properties. We close by analyzing to which extent the proposed explanations were verified by numerical studies and present the open questions in this field.
Acute Injuries of the Upper Thoracic Spine Associated With Paraplegia

A review of 35 cases of acute injury of the upper thoracic spine associated with paraplegia was done. In 32, a fracture-dislocation was present; in two, there was a dislocation without associated fracture; and in one, neither fracture nor dislocation was identified. A total of 22 cases conformed to a pattern of injury consisting of anterior fracture dislocation with disruption of the intervening facets joints and various vertebral body fractures. Tomography was necessary for characterization of the injuries. There was a 17% incidence of associated second level spinal injuries, usually a hyperextension injury of the cervical spine.
The Balance-Sample Size Frontier in Matching Methods for Causal Inference

We propose a simplified approach to matching for causal inference that simultaneously optimizes balance (similarity between the treated and control groups) and matched sample size. Existing approaches either fix the matched sample size and maximize balance or fix balance and maximize sample size, leaving analysts to settle for suboptimal solutions or attempt manual optimization by iteratively tweaking their matching method and rechecking balance. To jointly maximize balance and sample size, we introduce the matching frontier, the set of matching solutions with maximum possible balance for each sample size. Rather than iterating, researchers can choose matching solutions from the frontier for analysis in one step. We derive fast algorithms that calculate the matching frontier for several commonly used balance metrics. We demonstrate this approach with analyses of the effect of sex on judging and job training programs that show how the methods we introduce can extract new knowledge from existing data sets.
Detectors and experiments

The talks in the Program and the Conference parallel sessions make clear that high quality pixel vertex chambers are presently well developed and with continuing improvements (M. Caccia,1 X. Sun,2 M. Stanitzki,3 J. Qian4); that there are at least two major tracking chambers that are well studied, a TPC and silicon-strip chambers (H. Qi,5,6 C. Young,7,8 A. de Roeck9,10); that the energy measurement of photons and electrons is generally very good (H. Yang,11 S. Franchino12); and, that the last remaining detector that has not yet achieved the high precision required for good e+e− physics is the hadronic calorimeter for the measurement of jets, most importantly, jets from the decays of W and Z to quarks (S. Lee,13,14 M. Cascella,15 A. de Roeck16). The relationship of the detectors to physics and the overall design of detectors was addressed and questioned (Y. Gao,17 M. Ruan,18 G. Tonelli,19 H. Zhu,20 M. Mangano,21 C. Quigg22) in addition to precision time measurements in detectors (C. Tully23).
Zonostrophic instability driven by discrete particle noise

The consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provides a new interpretation of the random forcing that is ubiquitously invoked in stochastic models such as the second-order cumulant expansion or stochastic structural instability theory; neither intrinsic turbulence nor coupling to extrinsic turbulence is required. A representative calculation of the zonostrophic neutral curve is made for a simple two-field model of toroidal ion-temperature-gradient-driven modes. To the extent that the damping of zonal flows is controlled by the ion–ion collision rate, the point of zonostrophic instability is independent of that rate.
PREACHING TO THE CONVERTED? Pluralism, Participation and Party Websites

In this study, it is theorized that party websites play a distinctive role in two regards: (i) they function as a pluralistic civic forum by facilitating the voice of oppositional challengers and increasing the visibility of minor and fringe parties, so that attentive citizens can learn more about the range of electoral choices; (ii) in addition, party websites function as a channel for political participation by facilitating interactive linkages between citizens and parties. The debate about the function of the Internet for pluralism and participation is laid out in Part I. The supply-and-demand research design, including content analysis of 134 websites (supply) and surveys of the public using party websites (demand), in the 15 European Union member states, drawn from the Spring 2000 Euro-barometer, is outlined in Part II. The evidence for patterns of party competition in European party websites is examined in Part III and in Part IV the use of party websites among West Europeans is analyzed. Compared w...
Beyond Relaxation and Newton–Raphson: Solving AC OPF for Multi-Phase Systems With Renewables

This paper focuses on the AC Optimal Power Flow (OPF) problem for multi-phase systems. Particular emphasis is given to systems with high integration of renewables, where adjustments of the real and reactive output powers from renewable sources of energy are necessary in order to enforce voltage regulation. The AC OPF problem is known to be nonconvex (and, in fact, NP-hard). Convex relaxation techniques have been recently explored to solve the OPF task with reduced computational burden; however, sufficient conditions for tightness of these relaxations are only available for restricted classes of system topologies and problem setups. Identifying feasible power-flow solutions remains hard in more general problem formulations, especially in unbalanced multi-phase systems with renewables. To identify feasible and optimal AC OPF solutions in challenging scenarios where existing methods may fail, this paper leverages the Feasible Point Pursuit - Successive Convex Approximation algorithm—a powerful approach for general nonconvex quadratically constrained quadratic programs. The merits of the approach are illustrated using single- and multi-phase distribution networks with renewables, as well as several transmission systems.
Achieving Exact Cluster Recovery Threshold via Semidefinite Programming

The binary symmetric stochastic block model deals with a random graph of $n$ vertices partitioned into two equal-sized clusters, such that each pair of vertices is independently connected with probability $p$ within clusters and $q$ across clusters. In the asymptotic regime of $p=a \log n/n$ and $q=b \log n/n$ for fixed $a,b$ , and $n \to \infty $ , we show that the semidefinite programming relaxation of the maximum likelihood estimator achieves the optimal threshold for exactly recovering the partition from the graph with probability tending to one, resolving a conjecture of Abbe et al. Furthermore, we show that the semidefinite programming relaxation also achieves the optimal recovery threshold in the planted dense subgraph model containing a single cluster of size proportional to $n$ .
A new method for determining the optimal lagged ensemble.

We propose a general methodology for determining the lagged ensemble that minimizes the mean square forecast error. The MSE of a lagged ensemble is shown to depend only on a quantity called the cross-lead error covariance matrix, which can be estimated from a short hindcast dataset and parameterized in terms of analytic functions of time. The resulting parameterization allows the skill of forecasts to be evaluated for an arbitrary ensemble size and initialization frequency. Remarkably, the parameterization also can estimate the MSE of a burst ensemble simply by taking the limit of an infinitely small interval between initialization times. This methodology is applied to forecasts of the Madden Julian Oscillation (MJO) from version 2 of the Climate Forecast System (CFSv2). For leads greater than a week, little improvement is found in the MJO forecast skill when ensembles larger than 5 days are used or initializations greater than 4 times per day. We find that if the initialization frequency is too infrequent, important structures of the lagged error covariance matrix are lost. Lastly, we demonstrate that the forecast error at leads ≥ 10 days can be reduced by optimally weighting the lagged ensemble members. The weights are shown to depend only on the cross-lead error covariance matrix. While the methodology developed here is applied to CFSv2, the technique can be easily adapted to other forecast systems. This article is protected by copyright. All rights reserved.
A periodic table of ion charge-state distributions observed in the transition region between vacuum sparks and vacuum arcs

Ion charge-state distributions have been measured with high time resolution for short (20 /spl mu/s) and long (250 /spl mu/s) vacuum discharges of 300 A. Charge-state data for 3 /spl mu/s after discharge ignition and quasi-steady-state values are given for most conductive elements in a Periodic Table, including data for a few elements (rhodium, europium, and terbium) that were never before reported in the literature. Ion charge states are significantly higher at the beginning of the discharge and decay to their quasi-steady-state arc plasma values. It was found that the mean ion charge states can be fitted by functions of the form Q~=Q~/sub t/spl rarr//spl infin// [1+A exp(-t//spl tau/)] where A is an enhancement function that depends on the power density. For the present conditions, A/spl sim/1 and /spl tau//spl sim/50 /spl mu/s.
A beat frequency buncher

Abstract A superconducting high energy buncher operating at 13 12 times the linac frequency has been built and installed, to combine with the low energy buncher operating at 1 12 the linac frequency. The system is synchronized so the linac and high energy buncher beat frequency remain in phase with the low energy buncher. On linac cycles not corresponding to a primary bunch, the high energy buncher bunches the residual beam away from the linac longitudinal acceptance rather than into it. The resonator for the new high energy buncher was constructed by shortening an existing low-β resonator.
Zero-Gradient-Sum Algorithms for Distributed Convex Optimization: The Continuous-Time Case

This technical note presents a set of continuous-time distributed algorithms that solve unconstrained, separable, convex optimization problems over undirected networks with fixed topologies. The algorithms are developed using a Lyapunov function candidate that exploits convexity, and are called Zero-Gradient-Sum (ZGS) algorithms as they yield nonlinear networked dynamical systems that evolve invariantly on a zero-gradient-sum manifold and converge asymptotically to the unknown optimizer. We also describe a systematic way to construct ZGS algorithms, show that a subset of them actually converge exponentially, and obtain lower and upper bounds on their convergence rates in terms of the network topologies, problem characteristics, and algorithm parameters, including the algebraic connectivity, Laplacian spectral radius, and function curvatures. The findings of this technical note may be regarded as a natural generalization of several well-known algorithms and results for distributed consensus, to distributed convex optimization.
Existence of some signed magic arrays

Abstract We consider the notion of a signed magic array, which is an m × n rectangular array with the same number of filled cells s in each row and the same number of filled cells t in each column, filled with a certain set of numbers that is symmetric about the number zero, such that every row and column has a zero sum. We attempt to make progress toward a characterization of for which ( m , n , s , t ) there exists such an array. This characterization is complete in the case where n = s and in the case where n = m ; we also characterize three-fourths of the cases where n = 2 m .
THE USE OF CIRCULAR EXTERNAL FIXATORS IN THE MANAGEMENT OF LOWER LIMB TRAUMA IN DUBLIN: A 20-YEAR EXPERIENCE

The purpose of this study was to review the outcomes and complications of all circular external fixators (frames) used for the management of acute lower limb trauma in our institution over a twenty year period. We retrospectively reviewed a prospectively compiled database of all frames applied in our institution and identified all frames which were applied for acute lower limb trauma. We identified 68 fractures in 63 patients. There were 11 femoral fractures and 57 tibial fractures. All fractures were classified using the AO Classification system, and most fractures were Type C fractures. We used an Ilizarov frame in 53 patients and a Taylor Spatial Frame in 15 patients. The mean time in frame was 365 days for a femoral fracture and 230 days for a tibial fracture. There were five tibial non-unions giving an overall union rate of 93%. Factors associated with non-union included high energy trauma and cigarette smoking. The vast majority of lower limb fractures can be treated using ‘conventional’ methods. Complex fractures which are not amenable to open reduction and internal fixation or cast immobilisation can be treated in a frame with excellent results. The paucity of published reports regarding the use of frames for complex trauma reflects the under-utilisation of the technique.
Interpenetrating polymer networks

Interpenetrating polymer networks (IPNs) composed of two or more chemically distinct networks are not only intrinsically interesting as examples of macromolecular chemical topological isomerism but are in practice useful means of controlling mutual miscibility and phase morphology in crosslinked polymers. We will first review briefly the synthesis and properties of such IPN systems. This will be followed by an outline of a phenomenological theory of the phase stability and linearised theory of spinodal decomposition of binary, chemically quenched, low crosslink density IPNs recently developed by K. Binder and the author. Finally, we will discuss some aspects of the synthesis of ternary IPNs and the thermochromic properties of IPNs containing a crosslinked polydiacetylene.
Push and pull : a study of international migration from Nepal

This paper studies migration choices in the presence of liquidity constraints and varying costs of migration. This paper presents a simple theoretical framework that analyzes migration response to both push and pull factors in such settings. This framework implies that a shock to the push factors in the origin leads to differential observed response to migration to various destinations, as the shocks affect different parts of the wealth distribution. The implications of this framework are tested in the context of international migration from Nepal, using a panel of 452 villages observed at three periods in the 2000s. The analysis uses rainfall shocks and deaths due to conflict as "push" shocks and growth in manufacturing and construction in destination countries as "pull" shocks. The findings show that a rainfall shock that increases household income by US$ 100 increases migration to India by 54 percent but has no effect on migration elsewhere. An increase in conflict, which reduces consumption and amenity of the wealthier more, increases migration abroad, especially from urban areas. An increase in demand from the destination countries, especially the Gulf countries and Malaysia, has strong effects on migration to those destinations. These findings are consistent with the theoretical framework, and suggest the presence of large liquidity constraints. An increase in income can boost migration to India, whereas a reduction in the cost of migration might increase profitable migration elsewhere. The responsiveness to "pull" shocks suggests that households are willing to take advantage of these opportunities.
The theory of condensation and the critical point

The droplet or cluster theory of condensation is reviewed critically and extended. It is shown to imply that the condensation point is marked by a singularity of the thermodynamic potential as conjectured by Mayer. The singularity turns out to be an essential singularity at which all derivatives of the thermodynamic variables remain finite. The theory also yields an understanding of the uniqueness of the critical point (in contrast to an extended critical region or Derby-hat type of behaviour) and leads to relations between the various critical point singularities. A one-dimensional model is described with a Hamiltonian containing short-range many-body potentials. The exact solution of the model is sketched and shown to exhibit condensation and critical phenomena for suitable (fixed) potentials. The analysis confirms the conclusions of the cluster theory and thereby lends support to the validity of its underlying assumptions.
Landmarks in Existing Tissue at Wounds Are Utilized to Generate Pattern in Regenerating Tissue

Summary Regeneration in many organisms involves the formation of a blastema, which differentiates and organizes into the appropriate missing tissues. How blastema pattern is generated and integrated with pre-existing tissues is a central question in the field of regeneration. Planarians are free-living flatworms capable of rapidly regenerating from small body fragments [1]. A cell cluster at the anterior tip of planarian head blastemas (the anterior pole) is required for anterior-posterior (AP) and medial-lateral (ML) blastema patterning [2–4]. Transplantation of the head tip into tails induced host tissues to grow patterned head-like outgrowths containing a midline. Given the important patterning role of the anterior pole, understanding how it becomes localized during regeneration would help explain how wounds establish pattern in new tissue. Anterior pole progenitors were specified at the pre-existing midline of regenerating fragments, even when this location deviated from the ML median plane of the wound face. Anterior pole progenitors were specified broadly on the dorsal-ventral (DV) axis and subsequently formed a cluster at the DV boundary of the animal. We propose that three landmarks of pre-existing tissue at wounds set the location of anterior pole formation: a polarized AP axis, the pre-existing midline, and the dorsal-ventral median plane. Subsequently, blastema pattern is organized around the anterior pole. This process, utilizing positional information in existing tissue at unpredictably shaped wounds, can influence the patterning of new tissue in a manner that facilitates integration with pre-existing tissue in regeneration.
Some Developments in Gribov’s Approach to QCD

We review several developments in the formulation of QCD provided by the GZ action. These include the GZ-action at finite temperature, the relation of the horizon condition and the Kugo-Ojima confinement criterion, the relation of the horizon condition and the dual-Meisssner effect, the alternative derivation of the GZ action provided by the Maggiore-Schaden shift, and the spontaneous breaking of BRST symmetry. We conclude with a proposal for the definition of physical states in the presence of BRST breaking.
PRE-OPERATIVE PLANNING AND INTRA-OPERATIVE ASSESSMENT: HELPING TO IMPROVE OUTCOME

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intraoperative fracture) are careful preoperative planning and more recently, the option of intraoperative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient9s perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intraoperative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the preoperative plan intraoperatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.
Titan's atmosphere and climate

Titan is the only moon with a substantial atmosphere, the only other thick N2 atmosphere besides Earth's, the site of extraordinarily complex atmospheric chemistry that far surpasses any other solar system atmosphere, and the only other solar system body with stable liquid currently on its surface. The connection between Titan's surface and atmosphere is also unique in our solar system; atmospheric chemistry produces materials that are deposited on the surface and subsequently altered by surface-atmosphere interactions such as aeolian and fluvial processes resulting in the formation of extensive dune fields and expansive lakes and seas. Titan's atmosphere is favorable for organic haze formation, which combined with the presence of some oxygen-bearing molecules indicates that Titan's atmosphere may produce molecules of prebiotic interest. The combination of organics and liquid, in the form of water in a subsurface ocean and methane/ethane in the surface lakes and seas, means that Titan may be the ideal place in the solar system to test ideas about habitability, prebiotic chemistry, and the ubiquity and diversity of life in the universe. The Cassini-Huygens mission to the Saturn system has provided a wealth of new information allowing for study of Titan as a complex system. Here I review our current understanding of Titan's atmosphere and climate forged from the powerful combination of Earth-based observations, remote sensing and in situ spacecraft measurements, laboratory experiments, and models. I conclude with some of our remaining unanswered questions as the incredible era of exploration with Cassini-Huygens comes to an end.
A novel MAC protocol for wireless network using multi-beam directional antennas

The use of directional antennas in wireless networks has received growing attention because of its high spatial reuse and high antenna gains. The Medium Access Control(MAC) protocol with directional antennas is nontrivial due to the limitations in wireless environment. The existing protocols commonly assume that the nodes can operate in both directional and omni-directional modes. In this paper, we propose a new MAC protocol for multi-beam directional antennas. In the protocol, each beam-sector has its own control channel, thus the communications among different beam-sectors are independent. It uses the directional network allocation vector(DNAV) to record the establishment processes. After sensing all the sectors of the multi-beam antenna, it uses the global assignment strategy to assign the directional communication channels. Extensive simulation results show that our protocol can significantly improve the throughput of an entire wireless network at the expense of the slightly increased RTS/DRTS requests in the establishment process.
Radiation-reaction force on a small charged body to second order

In classical electrodynamics, an accelerating charged body emits radiation and experiences a corresponding radiation-reaction force, or self-force. We extend to higher order in the total charge a previous rigorous derivation of the electromagnetic self-force in flat spacetime by Gralla, Harte, and Wald. The method introduced by Gralla, Harte, and Wald computes the self-force from the Maxwell field equations and conservation of stress-energy in a limit where the charge, size, and mass of the body go to zero, and it does not require regularization of a singular self-field. For our higher-order computation, an adjustment of the definition of the mass of the body is necessary to avoid including self-energy from the electromagnetic field sourced by the body in the distant past. We derive the evolution equations for the mass, spin, and center-of-mass position of the body through second order. We derive, for the first time, the second-order acceleration dependence of the evolution of the spin (self-torque), as well as a mixing between the extended body effects and the acceleration-dependent effects on the overall body motion.
Perturbational and nonperturbational inversion of Rayleigh-wave velocities

The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-type relation for Rayleigh waves. In practice, the nonperturbational method can be used to provide a good starting model that can be iteratively improved with the perturbational method. Although the perturbational method is well-known, we solve the forward problem using an eigenvalue/eigenvector solver instead of the conventional approach of root finding. Features of the codes include the ability to handle any mix of phase or group velocity measurements, combinations of modes of any order, the presence of a surface water layer, computation of partial derivatives due to changes in material properties and layer boundaries, and the implementation of an automatic grid of layers that is optimally suited for the depth sensitivity of Rayleigh waves.
The Effects of Twombly and Iqbal

Ever since Twombly and Iqbal introduced the doctrine of plausibility pleading, a cottage industry of legal scholars (including myself) has undertaken to detect the effects of Twombly and Iqbal on litigants and case outcomes. Results so far have been equivocal, and it has been hard to make sense of the disparate methodologies and findings. In this article, I develop a comprehensive yet nontechnical framework for empirically testing the effects of Twombly and Iqbal on lower courts and litigants, taking into account a wide range of confounding factors and the numerous ways in which Twombly and Iqbal may have indirectly affected litigant behavior. Using this framework, I test for effects of Twombly and Iqbal on district court and litigant behavior using two datasets—one of administrative data covering over 700,000 cases, and one of detailed, hand- and machine-coded docket and complaint data covering a representative sample of nearly 2,000 cases. I also review existing findings. I find only limited evidence that Twombly and Iqbal, the two most important pleading cases in 50 years, have had a major effect on the behavior of lawyers and judges across all cases. For represented plaintiffs, rates of dismissal with prejudice have held steady, motions to dismiss remain uncommon, and settlement and filing patterns have not changed appreciably in the wake of Twombly and Iqbal. There is, however, some evidence of effects—potentially major effects—on pro se plaintiffs. Further, while case outcomes for represented plaintiffs have been largely unaffected by Twombly and Iqbal, there is evidence that lawyers changed their pleading and motion practice in the wake of those cases.
Information Theoretic Properties of Markov Random Fields, and their Algorithmic Applications

Markov random fields are a popular model for high-dimensional probability distributions. Over the years, many mathematical, statistical and algorithmic problems on them have been studied. Until recently, the only known algorithms for provably learning them relied on exhaustive search, correlation decay or various incoherence assumptions. Bresler gave an algorithm for learning general Ising models on bounded degree graphs. His approach was based on a structural result about mutual information in Ising models. Here we take a more conceptual approach to proving lower bounds on the mutual information. Our proof generalizes well beyond Ising models, to arbitrary Markov random fields with higher order interactions. As an application, we obtain algorithms for learning Markov random fields on bounded degree graphs on $n$ nodes with $r$-order interactions in $n^r$ time and $\log n$ sample complexity. Our algorithms also extend to various partial observation models.
Highly curved image sensors: a practical approach for improved optical performance

The significant optical and size benefits of using a curved focal surface for imaging systems have been well studied yet never brought to market for lack of a high-quality, mass-producible, curved image sensor. In this work we demonstrate that commercial silicon CMOS image sensors can be thinned and formed into accurate, highly curved optical surfaces with undiminished functionality. Our key development is a pneumatic forming process that avoids rigid mechanical constraints and suppresses wrinkling instabilities. A combination of forming-mold design, pressure membrane elastic properties, and controlled friction forces enables us to gradually contact the die at the corners and smoothly press the sensor into a spherical shape. Allowing the die to slide into the concave target shape enables a threefold increase in the spherical curvature over prior approaches having mechanical constraints that resist deformation, and create a high-stress, stretch-dominated state. Our process creates a bridge between the high precision and low-cost but planar CMOS process, and ideal non-planar component shapes such as spherical imagers for improved optical systems. We demonstrate these curved sensors in prototype cameras with custom lenses, measuring exceptional resolution of 3220 line-widths per picture height at an aperture of f/1.2 and nearly 100% relative illumination across the field. Though we use a 1/2.3” format image sensor in this report, we also show this process is generally compatible with many state of the art imaging sensor formats. By example, we report photogrammetry test data for an APS-C sized silicon die formed to a 30° subtended spherical angle. These gains in sharpness and relative illumination enable a new generation of ultra-high performance, manufacturable, digital imaging systems for scientific, industrial, and artistic use.
Predicting the end of lava flow-forming eruptions from space

Although the volcanological community places great emphasis on forecasting the onset of volcanic eruptions, knowing when an effusive eruption will end is just as important in terms of mitigating hazards. Wadge (J Volcanol Geotherm Res 11:139–168, 1981) postulated that the onset of an episodic, lava flow-forming basaltic eruption is characterized by a rapid increase in effusion rate to a maximum, before decaying over a longer period of time until the eruption ends. We used thermal infrared remote-sensing data acquired by NASA’s MODerate Resolution Imaging Spectroradiometer (MODIS) to derive time-averaged discharge rate (TADR) time series using the method of Harris et al. (J Geophys Res 102(B4):7985–8003, 1997) for 104 eruptions at 34 volcanoes over the last 15 years. We found that 32 eruptions followed the pattern described by Wadge (J Volcanol Geotherm Res 11:139–168, 1981). Based on the MODIS-derived maximum lava discharge rate and a decay constant that best fits the exponential waning phase (updated as each new MODIS TADR observation is added to the time series), the time at which the discharge equals zero, and thus the point at which effusion ends, can be predicted. The accuracy of the prediction improves with the number of data points so that, in the ideal case, the end of effusion can be retro-casted before half of the eruption duration has passed. This work demonstrates the possibility of predicting when an eruption will end using satellite-derived TADR time series acquired in near real time during that eruption. This prediction can be made after an eruption has reached its maximum lava discharge rate and the waning phase of the Wadge trend has begun. This approach therefore only applies to the case of eruption from a chamber undergoing an elastic release of energy during lava flow emplacement, and we provide examples of eruptions where it would not be applicable.
Emergency Control During Stability Crises by Tracking the Observation Decoupled Reference

Abstract In the last 10-12 years techniques were developed at Washington University for the control of the power system during Stability Crises in order to prevent system breakup. These techniques derive from the concept of observation decoupled reference (or local equilibrium reference). When the system state coincides with this reference it is at its stable equilibrium. While the reference has no physical identity or interpretation otherwise it can nevertheless serve to guide the system state to its stable equilibrium. This result can be acheived either by using a full set of simple control tools -one at each unit-but strictly local feedback or by using a sparse set of more sophisticated control tools along with communication between the units and the control center and central processing. The letter results, which are new and as yet unpublished, are especially appropriate for using an HV-DC system to stabilize an associated AC system. In this paper this entire area of work is summed up, its essential core exposed and some of its newest results introduced.
Pancreatic Islet Cell Carcinoma With Hypercalcemia. Primary Hyperparathyroidism or Humoral Hypercalcemia of Malignancy

Abstract A 60-year-old woman presented with hypercalcemla and was found to have metastatic pancreatic Islet cell carcinoma. Although clinical features were very suggestive of hyperparathyroldism, her parathyroid hormone levels were not elevated and no abnormal parathyroid tissue was detected by thallium-technetium or computed tomographic scanning techniques. Her hypercalcemia appeared to be due to a humoral factor-distinct from parathyrold hormone-that mimics the action of parathyroid hormone almost exactly. The various tools that may be used to differentiate primary hyperparathyroldism from the humoral hypercalcemia of malignancy are reviewed.