cssi/SciSciGPT-SciSciNet huggingface dataset:
New approaches to structure analysis

There are relationships among the phases and magnitudes of the structure factors that have not been extensively studied regarding their potential for enhancing procedures for structure determination. These relationships arise from a special way of writing the determinantal inequalities that form the necessary and sufficient conditions for a Fourier series to be non-negative. This particular form also lends itself readily to the development of probability measures by the use of the central limit theorem. Higher-order determinants are of interest. The relationships among the phases and magnitudes of the structure factors are algebraic relationships and the focus is on those which retain their reliability, even though the magnitudes of the structure factors contain experimental errors. The future utility of the algebraic relationships depends upon the development of suitable algorithms for solving them to obtain values for the unknown phases. One approach concerns a method for extending the range of least-squares calculations by modifying the defining equations without changing the global minima and by further altering the nature of the minimization function from time to time during the course of the least-squares calculation, while still preserving the global minima. The objective is to smooth the minimization function and alter the remaining false minima from time to time so that the minimization function is not trapped in a false minimum. Some calculations have been made that indicate the nature of the algebraic relationships among the phases and magnitudes and how the results of the calculations are benefited by having large values for the structure-factor magnitudes in the determinants. It is also noted that large numbers of lower-order determinants can be spawned from one large order one. A possible virtue of this is that the structure factors which appear in the one large determinant appear with great redundance in the lower-order ones. A question to be answered is whether it is better to use many lower-order determinants for the algebraic equations or one larger determinant, or perhaps some combinations. There are very many alternatives to pursue and probably extensive experimentation will be needed to determine what is optimal.
Chromosomes of Human Hepatoma Cell Lines

The karyotypes of three human hepatoma cell lines Hep G2, Hep 3B and PLC/PRF/5 were investigated by G- and C-banding techniques. In addition to ploidy changes, typical for most carcinoma cell lines, certain markers were found that remained stable throughout passage of these cultures. Chromosome I is involved in multiple translocations, resulting in at least three copies of the chromosome I heterochromatin region in each cell line. Inversion in the 9qh region is also seen. In addition, each of the cell lines consistently contains trisomy of 17q. The rearrangements of chromosome I are most striking in the Hep 3B and PLC/PRF/5 cell lines, which are derived from human hepatocellular carcinomas and contain integrated copies of the hepatitis B viral genome. These two cell lines are characterized by the presence of at least five copies of the I (p13 leads to q21) region that result from multiple deletions and/or translocations; by consistent trisomy and polymorphism of the 9qh region; and by trisomy of chromosome 10 (also involved in rearrangements). The Hep G2 and Hep 3B cell lines behave functionally as highly differentiated liver parenchymal cells and are karyologically distinguishable from PLC/PRF/5 both by the presence of trisomy of 6 (pter leads to q14) and by the finding that one of the homologues of chromosome 15 is 15q+.
A New Reagent (ZZAP) Having Multiple Applications in Immunohematology

A reagent (ZZAP) containing a mixture of 0.1 M dithiothreitol (DTT) plus 0.1% cysteine-activated papain was found to dissociate IgG immunoglobulin from red blood cells (RBC) of patients having a positive direct antiglobulin test (DAT) although this could not be achieved with either chemical alone. In all 67 patients tested, ZZAP treatment of IgG sensitized RBC reduced the strength of the DAT, and in all 52 instances tested, this allowed for accurate Rh phenotyping using slide/rapid tube typing reagents. This included five examples in which spontaneous agglutination that occurred in saline or 6% albumin was eliminated by ZZAP. Thus, all red blood cell typing for Rh-Hr antigens was accomplished using slide/rapid tube reagents making unnecessary the use of saline reactive or chemically modified antisera. Kidd antigen typing is also possible after ZZAP treatment of IgG sensitized RBC. In regard to warm autoabsorption tests, ZZAP treatment of 14 RC samples having a positive DAT proved preferable to heat elution technics since equal or greater amounts of IgG were removed by ZZAP and little or no hemolysis resulted. ZZAP has no effect on ABH, Rh or Kidd antigens but denatures Duffy, MNSs and all Kell antigens tested (K:1-K:7, K:11-K:14, K:18, K:19). This should prove valuable in certain investigations of multiple alloantibodies and, moreover, may allow for better characterization of Kell antigens.
Open chemistry: RESTful web APIs, JSON, NWChem and the modern web application.

An end-to-end platform for chemical science research has been developed that integrates data from computational and experimental approaches through a modern web-based interface. The platform offers an interactive visualization and analytics environment that functions well on mobile, laptop and desktop devices. It offers pragmatic solutions to ensure that large and complex data sets are more accessible. Existing desktop applications/frameworks were extended to integrate with high-performance computing resources, and offer command-line tools to automate interaction—connecting distributed teams to this software platform on their own terms. The platform was developed openly, and all source code hosted on the GitHub platform with automated deployment possible using Ansible coupled with standard Ubuntu-based machine images deployed to cloud machines. The platform is designed to enable teams to reap the benefits of the connected web—going beyond what conventional search and analytics platforms offer in this area. It also has the goal of offering federated instances, that can be customized to the sites/research performed. Data gets stored using JSON, extending upon previous approaches using XML, building structures that support computational chemistry calculations. These structures were developed to make it easy to process data across different languages, and send data to a JavaScript-based web client.
On a Conjecture Regarding Permutations which Destroy Arithmetic Progressions

Hegarty conjectured for $n\neq 2, 3, 5, 7$ that $\mathbb{Z}/n\mathbb{Z}$ has a permutation which destroys all arithmetic progressions mod $n$. For $n\ge n_0$, Hegarty and Martinsson demonstrated that $\mathbb{Z}/n\mathbb{Z}$ has a permutation destroying arithmetic progressions. However $n_0\approx 1.4\times 10^{14}$ and thus resolving the conjecture in full remained out of reach of any computational techniques. Using constructions modeled after those used by Elkies and Swaminathan for the case of $\mathbb{Z}/p\mathbb{Z}$ with $p$ being prime, this paper establishes the conjecture in full. Furthermore, our results are completely independent of the proof given by Hegarty and Martinsson.
THE OPTIMAL USE OF STEMS IN THE REVISION TOTAL KNEE ARTHROPLASTY

Introduction The use of stems in TKA revision surgery is well established. Stems off-load stress over a broad surface area of the diaphysis and help protect the metaphyseal interface areas from failure. Stems can provide an area of extra fixation. Uncemented Stems Pros and Cons Advantages (1) Expeditious, (2) Compatible with intramedullary based revision instrumentation (3) Easy to remove if necessary (4) By filling diaphysis they help guarantee axial alignment Disadvantages (1) They help off load stress, but how much fixation do they really provide? (2) They don9t fit all canal deformities, and under some circumstances can actually force implants into malalignment. (3) ? potential for end of stem pain Cemented Stems Pros and Cons Advantages (1) Cemented stem adds fixation in fresh metaphyseal and diaphyseal bone. (2) Proven 10-year track record. (3) Allow the surgeon to adjust for canal geometry abnormalities Disadvantages (1) More difficult to remove, if required. (2) They don9t fill the canal so they don9t guarantee alignment as well under most circumstances. Results Favorable results with uncemented and cemented stems have been reported in several series. Cemented stems have longer term data. Technique Issues Uncemented Stems (1) Take advantage of offset bolts, tibial trays, stems to fit the stem/implant to the patient9s anatomy. (2) Don9t let the stem force you into suboptimal implant position. (3) Longer stems can be narrower but help engage more diaphysis. (4) Do a good job of restoring/uncovering cancellous bone in metaphysis for cement interdigitation. The cement provides the fixation. Cemented Stems (1) Intra-operative x-ray with trials helps guarantee optimal alignment. (2) Use cement restrictors. (3) Cement tibia/femur separately Metaphyseal Fixation (1) Area of new emphasis. (2) Cones and sleeves can improve cemented and uncemented fixation.
The Impact of Trade Prices on Employment and Wages in the United States

This paper investigates the sensitivity of sectoral employment and wages in the United States to changes in foreign trade prices for 1980–90. Previous studies have concentrated mainly on the impact of changes in import prices on employment and wage levels. This paper estimates the impact of changes in both import and export prices on employment and wages in each of 12 three-digit standard industrial classification (SIC) manufacturing sectors. The basic conclusion is that, for most sectors, changes in trade prices do not have significant effects on employment and wages, although they generally have a larger impact on employment than on wages.
Approach to Acute Heart Failure in the Emergency Department.

Abstract Acute heart failure (AHF) patients rarely present complaining of ‘acute heart failure.' Rather, they initially present to the emergency department (ED) with a myriad of chief complaints, symptoms, and physical exam findings. Such heterogeneity prompts an initially broad differential diagnosis; securing the correct diagnosis can be challenging. Although AHF may be the ultimate diagnosis, the precipitant of decompensation must also be sought and addressed. For those AHF patients who present in respiratory or circulatory failure requiring immediate stabilization, treatment begins even while the diagnosis is uncertain. The initial diagnostic workup consists of a thorough history and exam (with a particular focus on the cause of decompensation), an EKG, chest X-ray, laboratory testing, and point-of-care ultrasonography performed by a qualified clinician or technologist. We recommend initial treatment be guided by presenting phenotype. Hypertensive patients, particularly those in severe distress and markedly elevated blood pressure, should be treated aggressively with vasodilators, most commonly nitroglycerin. Normotensive patients generally require significant diuresis with intravenous loop diuretics. A small minority of patients present with hypotension or circulatory collapse. These patients are the most difficult to manage and require careful assessment of intra- and extra-vascular volume status. After stabilization, diagnosis, and management, most ED patients with AHF in the United States (US) are admitted. While this is understandable, it may be unnecessary. Ongoing research to improve diagnosis, initial treatment, risk stratification, and disposition may help ease the tremendous public health burden of AHF.
Modulation Characteristics Of Semiconductor Laser Devices

Several aspects of the direct modulation characteristics of semiconductor lasers are discussed, including a brief review of some basic theory and a description of a computer-controlled measurement technique. Methods of extending the modulation bandwidth by changing external and internal parameters are also discussed. Proton-isolated tilted-facet and Zn-diffused window and continuous-stripe lasers are used as examples of devices which allow the modulation bandwidth to be controlled by varying parameters such as the photon lifetime, the spontaneous emission factor, and other aspects of the cavity 0. Measurements demonstrating modulation bandwidths of 6 to 7 GHz are also presented.
Strategic group formation in agent-based simulation:

Researchers tend to model people as individuals rather than as members of groups. This approach diminishes the impact of altruism and other group-supporting behaviors. For example, walkers may move...
Convolutional neural network for earthquake detection and location

The recent evolution of induced seismicity in Central United States calls for exhaustive catalogs to improve seismic hazard assessment. Over the last decades, the volume of seismic data has increased exponentially, creating a need for efficient algorithms to reliably detect and locate earthquakes. Today's most elaborate methods scan through the plethora of continuous seismic records, searching for repeating seismic signals. We leverage the recent advances in artificial intelligence and present ConvNetQuake, a highly scalable convolutional neural network for earthquake detection and location from a single waveform. We apply our technique to study the induced seismicity in Oklahoma, USA. We detect more than 17 times more earthquakes than previously cataloged by the Oklahoma Geological Survey. Our algorithm is orders of magnitude faster than established methods.
Trends in the Relative Household Income of Working-Age Men With Work Limitations Correcting the Record Using Internal Current Population Survey Data

Policy makers relying on public-use Current Population Survey (CPS) data to measure the success of government policies in overcoming the gap in economic well-being between working-age men with and ...
When Variability Trumps Volatility: Optimal Control and Value of Reverse Logistics in Supply Chains with Multiple Flows of Product

Problem definition : We study how to optimally control a multistage supply chain in which each location can initiate multiple flows of product, including the reverse flow of orders. We also quantif...
Bounds on the minimax rate for estimating a prior over a VC class from independent learning tasks

Abstract We study the optimal rates of convergence for estimating a prior distribution over a VC class from a sequence of independent data sets respectively labeled by independent target functions sampled from the prior. We specifically derive upper and lower bounds on the optimal rates under a smoothness condition on the correct prior, with the number of samples per data set equal the VC dimension. These results have implications for the improvements achievable via transfer learning. We additionally extend this setting to real-valued function, where we establish consistency of an estimator for the prior, and discuss an additional application to a preference elicitation problem in algorithmic economics.
Business Cases for Major Public Infrastructure Projects in Canada

When governments announce that they are going to spend vast sums of taxpayers’ money on a new public infrastructure project, you can be certain they will praise all the terrific new benefits that the project will bring to citizens, making everyone’s life easier, safer, greener and better. But this does not tell us whether we are better off as a society, after accounting for the cost of these projects borne by taxpayers today and well into the future. In reality, there is a meaningful risk that a project undertaken without a proper business case could end up making citizens’ lives worse. That new commuter train might look sleek and shiny and seem convenient for some, but a close business case analysis of recent transit projects in Canada’s three largest cities suggests that in as many as four cases out of 21 projects, the burden of paying for the projects does not justify the public investment. In a review of thirteen recent public transit projects in the Greater Toronto and Hamilton Area (GTHA), at least three projects had benefits that fell short of the costs. Yet, all three projects went ahead (or have been funded). Only one project showed large net benefits for citizens once all considerations were accounted for. Three projects showed small net benefits – of a size that can be easily offset by a modest cost over-run. The six remaining projects did not have any publicly available business cases. In the Greater Montreal area, a review of three recent major transit projects turned up no evidence of a publicly available business case for any of them. As a result, Montrealers are in the dark as to how much benefit or value destruction the three projects are responsible for. Things are far more encouraging in Vancouver, however, where three out of the five major transit projects undertaken or funded in recent years were backed by business cases showing a net benefit. Only one project did not show a net benefit and one project did not have a business case. Of course, business cases only make projections about net benefits. Rarely, if ever, do governments undertake an ex post review to determine whether their estimates were correct and if the project has delivered — or destroyed — the value expected. Given that these projects can run into the billions of dollars, tie up immense amounts of government resources, and can cause any number of disruptions to business and families, it is remarkable how little cost-benefit scrutiny is brought to bear on them. Without these ex post business cases, there can be no lessons learned from past projects. There can be no assurance that we can make better investment decisions going forward.
Access to Data and Number of Iterations: Dual Primal Algorithms for Maximum Matching under Resource Constraints

In this article, we consider graph algorithms in models of computation where the space usage (random accessible storage, in addition to the read-only input) is sublinear in the number of edges m and the access to input is constrained. These questions arise in many natural settings, and in particular in the analysis of streaming algorithms, MapReduce or similar algorithms, or message passing distributed computing that model constrained parallelism with sublinear central processing.We focus on weighted nonbipartite maximum matching in this article. For any constant p > 1, we provide an iterative sampling-based algorithm for computing a (1 − e)-approximation of the weighted nonbipartite maximum matching that uses O(p/e) rounds of sampling, and O(n1+1/p) space. The results extend to b-Matching with small changes. This article combines adaptive sketching literature and fast primal-dual algorithms based on relaxed Dantzig-Wolfe decision procedures. Each round of sampling is implemented through linear sketches and can be executed in a single round of streaming or two rounds of MapReduce. The article also proves that nonstandard linear relaxations of a problem, in particular penalty-based formulations, are helpful in reducing the adaptive dependence of the iterations.
Pendeo-Epitaxy - A New Approach for Lateral Growth of Gallium Nitride Structures

A new process route for lateral growth of nearly defect free GaN structures via Pendeo-epitaxy is discussed. Lateral growth of GaN films suspended from {11 $$\bar 2$$ 0} side walls of [0001] oriented GaN columns into and over adjacent etched wells has been achieved via MOVPE technique without the use of, or contact with, a supporting mask or substrate. Pendeo-epitaxy is proposed as the descriptive term for this growth technique. Selective growth was achieved using process parameters that promote lateral growth of the {11 $$\bar 2$$ 0} planes of GaN and disallow nucleation of this phase on the exposed SiC substrate. Thus, the selectivity is provided by tailoring the shape of the underlying GaN layer itself consisting of a sequence of alternating trenches and columns, instead of selective growth through openings in SiO2 or SiNx mask, as in the conventional lateral epitaxial overgrowth (LEO).Two modes of initiation of the pendeo-epitaxial GaN growth via MOVPE were observed: Mode A - promoting the lateral growth of the {11 $$\bar 2$$ 0} side facets into the wells faster than the vertical growth of the (0001) top facets; and Mode B - enabling the top (0001) faces to grow initially faster followed by the pendeo-epitaxial growth over the wells from the newly formed {11 $$\bar 2$$ 0} side facets. Four-to-five order decrease in the dislocation density was observed via transmission electron microscopy (TEM) in the pendeo-epitaxial GaN relative to that in the GaN columns. TEM observations revealed that in pendeo-epitaxial GaN films the dislocations do not propagate laterally from the GaN columns when the structure grows laterally from the sidewalls into and over the trenches. Scanning electron microscopy (SEM) studies revealed that the coalesced regions are either defect-free or sometimes exhibit voids. Above these voids the PEGaN layer is usually defect free.
Hypothalamic epigenetics driving female puberty

Puberty involves a series of morphological, physiological and behavioural changes during the last part of the juvenile period that culminates in the attainment of fertility. The activation of the pituitary-gonadal axis by increased hypothalamic secretion of gonadotrophin-releasing hormone (GnRH) is an essential step in the process. The current hypothesis postulates that a loss of transsynaptic inhibition and a rise in excitatory inputs are responsible for the activation of GnRH release. Similarly, a shift in the balance in the expression of puberty activating and puberty inhibitory genes exists during the pubertal transition. In addition, recent evidence suggests that the epigenetic machinery controls this genetic balance, giving rise to the tantalising possibility that epigenetics serves as a relay of environmental signals known for many years to modulate pubertal development. Here, we review the contribution of epigenetics as a regulatory mechanism in the hypothalamic control of female puberty.
Host genetic variation and its microbiome interactions within the Human Microbiome Project

Despite the increasing recognition that microbial communities within the human body are linked to health, we have an incomplete understanding of the environmental and molecular interactions that shape the composition of these communities. Although host genetic factors play a role in these interactions, these factors have remained relatively unexplored given the requirement for large population-based cohorts in which both genotyping and microbiome characterization have been performed. We performed whole-genome sequencing of 298 donors from the Human Microbiome Project (HMP) healthy cohort study to accompany existing deep characterization of their microbiomes at various body sites. This analysis yielded an average sequencing depth of 32x, with which we identified 27 million (M) single nucleotide variants and 2.3 M insertions-deletions. Taxonomic composition and functional potential of the microbiome covaried significantly with genetic principal components in the gastrointestinal tract and oral communities, but not in the nares or vaginal microbiota. Example associations included validation of known associations between FUT2 secretor status, as well as a variant conferring hypolactasia near the LCT gene, with Bifidobacterium longum abundance in stool. The associations of microbial features with both high-level genetic attributes and single variants were specific to particular body sites, highlighting the opportunity to find unique genetic mechanisms controlling microbiome properties in the microbial communities from multiple body sites. This study adds deep sequencing of host genomes to the body-wide microbiome sequences already extant from the HMP healthy cohort, creating a unique, versatile, and well-controlled reference for future studies seeking to identify host genetic modulators of the microbiome.
Mediating conflicts over sacred lands

Mediating conflicts over sacred lands, a unique subset of public conflicts and international conflict with a religion component, requires sensitivity to the concept of the sacred and the unique contexts within which they occur. Sacred lands disputes may emerge from competing incompatible commercial and religious uses, demands for exclusive use, and efforts to undermine religious legitimacy. These aspects of conflicts over sacred lands require mediator consideration of their peculiar dynamics, including clashes of worldviews, indivisibility, and territorial access to the divine.
Multiscale higher-order TV operators for L1 regularization.

In the realm of signal and image denoising and reconstruction, $$\ell _1$$ regularization techniques have generated a great deal of attention with a multitude of variants. In this work, we demonstrate that the $$\ell _1$$ formulation can sometimes result in undesirable artifacts that are inconsistent with desired sparsity promoting $$\ell _0$$ properties that the $$\ell _1$$ formulation is intended to approximate. With this as our motivation, we develop a multiscale higher-order total variation (MHOTV) approach, which we show is related to the use of multiscale Daubechies wavelets. The relationship of higher-order regularization methods with wavelets, which we believe has generally gone unrecognized, is shown to hold in several numerical results, although notable improvements are seen with our approach over both wavelets and classical HOTV. These results are presented for 1D signals and 2D images, and we include several examples that highlight the potential of our approach for improving two- and three-dimensional electron microscopy imaging. In the development approach, we construct the tools necessary for MHOTV computations to be performed efficiently, via operator decomposition and alternatively converting the problem into Fourier space.
Lessons in fisheries politics

Abstract Advocates for recreational fishing, public servants charged with fisheries management, and scientists and other experts who provide objective advice, all need to understand the nature and dimensions of fisheries politics. Accusing someone of “playing politics” usually is intended as a criticism, even an insult. But politics is the social process by which differences are expressed and resolved. If you don’t have differences, then you don’t have politics. A political situation, whether it is in a family, the workplace, government administration or a contest for public office is the process through which differences are discussed and settled. Fisheries politics takes place at many levels. It determines the resources available to manage fisheries and understand their impacts. It defines the relationship between conservation and extraction. It determines the allocation of harvest between competing interests. It sets the international rules between nations for the conservation and sharing of migratory and straddling stocks. Underlying these political relationships are rules and norms of political behavior that can be learned and practised by those who wish to maximize their influence over how fisheries are managed and practised. Canada’s West Coast provides a useful example of efforts by the Canadian government to facilitate fisheries politics by providing structures and processes within which different interests can contribute to the politics of fisheries management. A participant-observer brings his perspective as both an ardent angler and a political scientist specializing in the relationship between interest groups and government to suggest some rules for effective engagement in fisheries politics.
The Benefits and Costs of the TARP Bailouts: A Critical Assessment

We assess benefits and costs of the Troubled Asset Relief Program (TARP) based on theory, data, and empirical research to date. TARP was intended to attenuate systemic risk and improve the real eco...
Robust Feature Clustering for Unsupervised Speech Activity Detection

In certain applications such as zero-resource speech processing or very-low resource speech-language systems, it might not be feasible to collect speech activity detection (SAD) annotations. However, the state-of-the-art supervised SAD techniques based on neural networks or other machine learning methods require annotated training data matched to the target domain. This paper establish a clustering approach for fully unsupervised SAD useful for cases where SAD annotations are not available. The proposed approach leverages Harti-gan dip test in a recursive strategy for segmenting the feature space into prominent modes. Statistical dip is invariant to distortions that lends robustness to the proposed method. We evaluate the method on NIST OpenSAD 2015 and NIST OpenSAT 2017 public safety communications data. The results showed the superiority of proposed approach over the two-component GMM baseline.
Stochastic processes constrain the within and between host evolution of influenza virus

The evolutionary dynamics of influenza virus ultimately derive from processes that take place within and between infected individuals. Here we define influenza virus dynamics in human hosts through sequencing of 249 specimens from 200 individuals collected over 6290 person-seasons of observation. Because these viruses were collected from individuals in a prospective community-based cohort, they are broadly representative of natural infections with seasonal viruses. Consistent with a neutral model of evolution, sequence data from 49 serially sampled individuals illustrated the dynamic turnover of synonymous and nonsynonymous single nucleotide variants and provided little evidence for positive selection of antigenic variants. We also identified 43 genetically-validated transmission pairs in this cohort. Maximum likelihood optimization of multiple transmission models estimated an effective transmission bottleneck of 1-2 genomes. Our data suggest that positive selection is inefficient at the level of the individual host and that stochastic processes dominate the host-level evolution of influenza viruses.
Natural Convective Flow and Heat Transfer in a Collector Storage With an Immersed Heat Exchanger: Numerical Study

A three-dimensional model and dimensionless scale analysis of the transient fluid dynamics and heat transfer in an inclined adiabatic water-filled enclosure with an immersed cylindrical cold sink is presented. The geometry represents an integral collector storage system with an immersed heat exchanger. The modeled enclosure has an aspect ratio of 6:1 and is inclined at 30 degrees to the horizontal. The heat exchanger is represented by a constant surface temperature horizontal cylinder positioned near the top of the enclosure. A scale analysis of the transient heat transfer process identifies four temporal periods: conduction, quasi-steady, fluctuating and decay. It also provides general formulations for the transient Nusselt number, and volume averaged water temperature in the enclosure. Insight to the transient fluid and thermal processes is provided by presentation of instantaneous flow streamlines and isotherm contours during each transient period. The flow field consists of two distinct zones. The zone above the cold sink is nearly stagnant. The larger zone below the sink is one of strong mixing and recirculation initiated by the cold plume formed in the boundary layer of the cylindrical sink. Correlations predicted with the model for the transient Nusselt number and the dimensionless volume averaged tank temperature expressed in terms of the initial Rayleigh number compare favorably to prior measured data.Copyright © 2005 by ASME
Self-organization of a human organizer by combined Wnt and Nodal signalling

In amniotes, the development of the primitive streak and its accompanying 'organizer' define the first stages of gastrulation. Although these structures have been characterized in detail in model organisms, the human primitive streak and organizer remain a mystery. When stimulated with BMP4, micropatterned colonies of human embryonic stem cells self-organize to generate early embryonic germ layers 1 . Here we show that, in the same type of colonies, Wnt signalling is sufficient to induce a primitive streak, and stimulation with Wnt and Activin is sufficient to induce an organizer, as characterized by embryo-like sharp boundary formation, markers of epithelial-to-mesenchymal transition and expression of the organizer-specific transcription factor GSC. Moreover, when grafted into chick embryos, human stem cell colonies treated with Wnt and Activin induce and contribute autonomously to a secondary axis while inducing a neural fate in the host. This fulfils the most stringent functional criteria for an organizer, and its discovery represents a milestone in human embryology.
Parents' Beliefs About Their Children's Academic Ability: Implications for Educational Investments

Schools worldwide distribute information to parents about their children's academic performance. Do frictions prevent parents, particularly low-income parents, from accessing this information to make decisions? A field experiment in Malawi shows that, at baseline, parents' beliefs about their children's academic performance are often inaccurate. Providing parents with clear, digestible performance information causes them to update their beliefs and adjust their investments: they increase the school enrollment of their higher-performing children, decrease the enrollment of lower-performing children, and choose educational inputs that are more closely matched to their children's academic level. Heterogeneity analysis suggests information frictions are worse among the poor.
Applications of Parallel-Element, Embedded Mesh-Cap Acoustic Liner Concepts

This study explores progress achieved with 2DOF, 3DOF, and MDOF acoustic liners constructed with mesh caps embedded within a honeycomb core. These liner configurations offer potential for broadband noise reduction, and are suitable for conventional aircraft implementation. Samples for each configuration are tested in the NASA normal incidence tube and grazing flow impedance tube, with and without a wire mesh facesheet. Impedances based on these measured data compare favorably with those predicted using a transmission line impedance prediction model. Predicted impedances are then used as input for an aeroacoustic propagation code to compute axial acoustic pressure distributions in the grazing flow tube. These predicted distributions compare favorably with the corresponding measured distributions at frequencies away from the frequency of peak attenuation, but suffer slight degradation for frequencies very near the peak attenuation frequency, where the predicted results are sensitive to input impedance changes. As expected, the noise reduction frequency range increases as more degrees of freedom are included. Although the specific results achieved herein may differ from those that would be achieved with other 2DOF, 3DOF, and MDOF liners, this comparison highlights some of the key features that can be exploited in the design of parallel-element, embedded mesh-cap liners.
A state variable for crumpled thin sheets

Despite the apparent ease with which sheets of paper are crumpled and tossed away, crumpling dynamics are often considered a paradigm of complexity. This arises from the infinite number of configurations that disordered, crumpled sheets can take. Here we experimentally show that key aspects of axially confined crumpled Mylar sheets have a very simple description; evolution of damage in crumpling dynamics can largely be described by a single global quantity—the total length of creases. We follow the evolution of the damage network in repetitively crumpled elastoplastic sheets, and show that the dynamics are deterministic, depending only on the instantaneous state of the crease network and not on the crumpling history. We also show that this global quantity captures the crumpling dynamics of a sheet crumpled for the first time. This leads to a remarkable reduction in complexity, allowing a description of a highly disordered system by a single state parameter.
Aeroservoelastic Optimization under Stochastic Gust Constraints

This work considers the aeroservoelastic optimization of a highly flexible transport aircraft wingbox with several control surfaces distributed along the trailing edge. The steady deflections of the control surfaces are designed to alleviate static maneuver loads, while the unsteady deflections are designed to alleviate stochastic continuous gust disturbances. Spatially-detailed unsteady stochastic stress and panel buckling constraints are formulated via modal acceleration, and by methods to locate the most-probable failure point along an equal-probability hypersurface. For the case considered here, it is found that the inclusion of such gust constraints during optimization presents a sizable structural mass penalty. In some cases, this mass penalty can be completely recovered with controlled gust load alleviation.
Is the Longleaf Type a Climax

What is a climax? The commonly accepted definition is, a type of vegetation which has adapted itself over a long period to a set of environmental conditions, so completely that it is stabilized as long as those conditions remain unchanged. In a narrower sense, a climax type assumes adaptation to a given set of conditions excluding other conditions. The conditions excluded are those which would usually result in disturbance of this stability or equilibrium. These are; fire, under the conception that fire acts to destroy the stand; insects, when epidemic; destructive winds. The effect of imported diseases and insects, or of man's interference in lumbering, destroys the balance and the type may completely change. Climax types may therefore yield at any time to new conditions to which they are not adapted. Excluding the above factors, there would remain only the climatic and soil factors of site. These factors, isolated from the effects of the so-called destructive group, would finally establish a forest type in which the only surviving species would be those capable of enduring the shade of a forest cover during their establishment. This condition necessitates the elimination of fire, wind, insect epidemics and disease for periods longer than the life span of species which cannot endure shade. When, as with Douglas fir, this span is from 300 to 500 years, and the environmental conditions are such as to create extreme conflagration hazard at intervals of from 3 to io years, the establishment of climax types of more shade-enduring species, which are usually inferior in utility, is a pure accident. In the life span of the species, any factor, such as fire, which can be depended on to occur even once within that period, and create conditions favorable to its reproduction, may become the determining factor in its perpetuation as against shadeenduring or so-called climax types. The characteristics of such a relationship are that while fire is required (or its man-made substitute, lumbering) for the removal of the overwood shade and establishment of reproduction, the total exclusion of subsequent fires is equally necessary for survival of this reproduction. The distribution and composition of the forest types in such a region is, therefore, very irregular, much young growth is destroyed prematurely, and here and there a patch may finally attain the climax or shade-enduring type. If for any reason the normal or natural frequency of fire is increased so that its chance of occurrence on any given area becomes once in IO to i5 years, the only hope for survival of the tree species is ability to develop a fire resistant bark within such a period and the fact that the fires when they do occur will
Flow-time Optimization for Concurrent Open-Shop and Precedence Constrained Scheduling Models.

Scheduling a set of jobs over a collection of machines is a fundamental problem that needs to be solved millions of times a day in various computing platforms: in operating systems, in large data clusters, and in data centers. Along with makespan, flow-time, which measures the length of time a job spends in a system before it completes, is arguably the most important metric to measure the performance of a scheduling algorithm. In recent years, there has been a remarkable progress in understanding flow-time based objective functions in diverse settings such as unrelated machines scheduling, broadcast scheduling, multi-dimensional scheduling, to name a few. Yet, our understanding of the flow-time objective is limited mostly to the scenarios where jobs have no dependencies. On the other hand, in almost all real world applications, think of MapReduce settings for example, jobs have dependencies that need to be respected while making scheduling decisions. In this paper, we take first steps towards understanding this complex problem. In particular, we consider two classical scheduling problems that capture dependencies across jobs: 1) concurrent open-shop scheduling (COSSP) and 2) precedence constrained scheduling. Our main motivation to study these problems specifically comes from their relevance to two scheduling problems that have gained importance in the context of data centers: co-flow scheduling and DAG scheduling. We design almost optimal approximation algorithms for COSSP and PCSP, and show hardness results.
Metabolism of Public Research Organizations: How Do Laboratories Consume State Subsidies?

The goal of this study is to suggest a new approach, called metabolism of research organizations, which analyzes how labs consume public funding to manage their structures. A case study of one of the biggest European public research organizations reveals that public funding for research is mainly used for the cost of personnel, which has a growth rate higher than revenue (state subsidy and public contracts over time). This imbalance of growth rates within public research body under study seems to be a source of organizational inefficiencies. This new approach can support best practices of R&D management.
Analysts’ stock ownership and stock recommendations

Abstract Using hand-collected information, we find that analysts who own stock in a company they follow make more informative recommendations and exert more effort in covering the company. However, we also find that analysts with stock ownership issue more optimistic target price forecasts. These findings suggest that analysts’ stock ownership enhances the credibility of their recommendations by conveying their superior information, but also induces analysts to bias upwards their target price forecasts. Surprisingly, we find that 56% of analysts owning stock terminate their ownership while having a buy recommendation outstanding, suggesting a potentially widespread violation of the regulations on analysts’ research.
The effect of local political corruption on earnings quality

Our study examines whether political corruption of a local government at judicial district level influences earnings management activities of firms located in a corrupt area. Prior studies suggest that there is an association between political connections and earnings quality (e.g., Braam et al. in Int J Account 50: 111–141, 2015; Harymawan and Nowland in Int J Account Inf Manag 24: 339–356, 2016). Nevertheless, there is little research regarding the impact of local political corruption at judicial district level on financial reporting quality. Using a sample of publicly listed U.S. firms from 2007 to 2014, we find that firms located in corrupt regions are more likely to manage earnings through accruals management and real activities manipulation (i.e., sales manipulation and overproduction). An additional analysis indicates that firms located in corrupt regions have less earnings persistence and are more likely to use positive discretionary accruals to meet or beat the consensus analysts’ earnings forecast. Taken together, our study extends prior literature by addressing the concern regarding the influence of local political corruption on firms’ earnings quality.
Gene regulatory divergence between locally adapted ecotypes in their native habitats.

Local adaptation is a key driver of ecological specialization and the formation of new species. Despite its importance, the evolution of gene regulatory divergence among locally adapted populations is poorly understood, especially how that divergence manifests in nature. Here, we evaluate gene expression divergence and allele-specific gene expression responses for locally adapted coastal perennial and inland annual accessions of the yellow monkeyflower, Mimulus guttatus, in a field reciprocal transplant experiment. Overall, 6765 (73%) of surveyed genes were differentially expressed between coastal and inland habitats, while 7213 (77%) were differentially expressed between the coastal perennial and inland annual accessions. Cis-regulatory variation was pervasive, affecting 79% (5532) of differentially expressed genes. We detected trans effects for 52% (3611) of differentially expressed genes. Expression plasticity of alleles across habitats (G × E interactions) appears to be relatively common (affecting 18% of transcripts) and could minimize fitness trade-offs at loci that contribute to local adaptation. We also found evidence that at least one chromosomal inversion may act as supergene by holding together haplotypes of differentially expressed genes, but this pattern depends on habitat context. Our results highlight multiple key patterns regarding the relationship between gene expression and the evolution of locally adapted populations.
Neural Ranking Models for Temporal Dependency Structure Parsing

We design and build the first neural temporal dependency parser. It utilizes a neural ranking model with minimal feature engineering, and parses time expressions and events in a text into a temporal dependency tree structure. We evaluate our parser on two domains: news reports and narrative stories. In a parsing-only evaluation setup where gold time expressions and events are provided, our parser reaches 0.81 and 0.70 f-score on unlabeled and labeled parsing respectively, a result that is very competitive against alternative approaches. In an end-to-end evaluation setup where time expressions and events are automatically recognized, our parser beats two strong baselines on both data domains. Our experimental results and discussions shed light on the nature of temporal dependency structures in different domains and provide insights that we believe will be valuable to future research in this area.
Mobile broadband internet access service is a commercial mobile service, and hence must be regulated as a common carrier service

The FCC’s Restoring Internet Freedom Order reclassified mobile broadband service from a commercial mobile radio service to a private mobile radio service, thereby eliminating common carrier regulat...
SAIL: Machine Learning Guided Structural Analysis Attack on Hardware Obfuscation

Obfuscation is a technique for protecting hardware intellectual property (IP) blocks against reverse engineering, piracy, and malicious modifications. Current obfuscation efforts mainly focus on functional locking of a design to prevent black-box usage. They do not directly address hiding design intent through structural transformations, which is an important objective of obfuscation. We note that current obfuscation techniques incorporate only: (1) local, and (2) predictable changes in circuit topology. In this paper, we present SAIL, a structural attack on obfuscation using machine learning (ML) models that exposes a critical vulnerability of these methods. Through this attack, we demonstrate that the gate-level structure of an obfuscated design can be retrieved in most parts through a systematic set of steps. The proposed attack is applicable to all forms of logic obfuscation, and significantly more powerful than existing attacks, e.g., SAT-based attacks, since it does not require the availability of golden functional responses (e.g., an unlocked IC). Evaluation on benchmark circuits show that we can recover an average of about 84% (up to 95%) transformations introduced by obfuscation. We also show that this attack is scalable, flexible, and versatile.