A Streaming Multi-GPU Implementation of Image Simulation Algorithms for Scanning Transmission Electron Microscopy

Simulation of atomic resolution image formation in scanning transmission electron microscopy can require significant computation times using traditional methods. A recently developed method, termed plane-wave reciprocal-space interpolated scattering matrix (PRISM), demonstrates potential for significant acceleration of such simulations with negligible loss of accuracy. Here we present a software package called Prismatic for parallelized simulation of image formation in scanning transmission electron microscopy (STEM) using both the PRISM and multislice methods. By distributing the workload between multiple CUDA-enabled GPUs and multicore processors, accelerations as high as 1000x for PRISM and 30x for multislice are achieved relative to traditional multislice implementations using a single 4-GPU machine. We demonstrate a potentially important application of Prismatic, using it to compute images for atomic electron tomography at sufficient speeds to include in the reconstruction pipeline. Prismatic is freely available both as an open-source CUDA/C++ package with a graphical user interface and as a Python package, PyPrismatic

The Perspective of a Junior Circuit Judge on Judicial Modesty

I appreciate the invitation to deliver the Dunwody Lecture this year, and I am grateful that this occasion has allowed me to visit, for the first time, one of the premier law schools in this Circuit and our nation. The Levin College of Law enjoys an excellent reputation for the education of lawyers. It is the alma mater of three judges of our court, and each year top graduates of this college serve our court with distinction as law clerks. I hope this visit will be the first of many to come for me. My topic today is judicial modesty, which some critics of the federal judiciary might say is an oxymoron. After all, these critics, in recent years, have dubbed it “the imperial judiciary,” “the most dangerous branch,” and “our judicial oligarchy.” Modesty is not a typical charge against the federal courts. This problem is not new. As far back as the early nineteenth century, the federal judiciary has had its critics. As historian Forrest McDonald has explained, “To most Jeffersonians, the federal judiciary stood as a barrier to the realization of the kind of society they envisioned for America . . . .” Thomas Jefferson described the judiciary as “[t]he great object of my fear,” and he may have been the first to call it “the most dangerous” branch. He mocked the federal judiciary as “our foreign department.” Even in the eyes of the contemporary legal profession, the federal judiciary still often suffers from a reputation for pomposity and even arrogance. Consider the popularity of a parody sung by a group of lawyers from Austin, Texas, who moonlight as musicians and call themselves “The Bar and Grill Singers.” They entertain audiences at bar conferences with a tune entitled “Appointed Forever,” which is a remake of the song “Happy Together” by The Turtles. It begins, Imagine me as God. I do. I think about it day and night. It feels so right. To be a federal district judge and know that I’m Appointed forever. The chorus is even funnier and more biting: I’m a federal judge and I’m smarter than you. For all my life. I can do whatever I want to do. For all my life. Contrast the reputation of the federal judiciary reflected in this musical parody with the sober requests of leading federal judges, in recent years, for an age of judicial modesty. This desire has been expressed by both Chief Justice John Roberts, Jr. and Circuit Judge Richard Posner. Their call has been widely praised. I too welcome the call for an age of judicial modesty, and when you consider the contrast between the judiciary and the political branches, there is plenty about our unique branch that lends itself to the virtue of modesty. While judges shun cameras and microphones and protest legislative attempts to allow those implements of the news media into courtrooms, political officers rarely miss an opportunity to appear on broadcasts of the mass media. While politicians use the time-honored tool of a press conference, judges communicate through written opinions often published almost anonymously as “per curiam.” While politicians are watched closely for their appearances and fashions, judges are rarely seen by the public and then only at an elevated distance dressed in plain black robes. Early on, Chief Justice John Marshall shunned political controversy when he wore a black robe as a statement of the need for judicial modesty. A biographer of Marshall, Jean Edward Smith, explained that Marshall led by example when he took the oath of office in February 1801: Breaking with tradition, he wore a plain black robe in the republican fashion of the judges of the Virginia court of appeals. The other justices, Cushing, Chase, and Washington, were attired either in the traditional scarlet and ermine of the King’s Bench or their individual academic gowns—the “party-colored robes” of an oppressive judiciary, in the words of Senator Stevens Thomson Mason. By wearing black, Marshall was making a quiet statement. He had seen the Federalists self-destruct electorally through an excess of hubris, and he recognized that the Court was on shaky ground. Why flaunt the colors of the English judiciary when the black robes worn by Pendleton and Wythe would do just as well? The decision had symbolic importance, but the chief justice had another motive. Marshall was a small-r republican and he was uncomfortable with trappings of power. I draw the contrast of the judiciary with the political branches not as a critic of politicians but as a former politician who respects their vital work. The officers of the political branches are not stewards of modest power; they develop national policies and must remain accessible and accountable to the people. When the judicial role of applying the law fairly and impartially is contrasted with the power and energy of the elected branches, the judiciary should be considered the modest branch. To be sure, there are routine practices of our peculiar branch that suggest the judiciary routinely succumbs to the temptation to be immodest. After all, there is a courtroom decorum that requires everyone to stand when judges enter the room, lawyers to call judges “Your Honor,” and invocations for God to save the judiciary as a bulwark of our free nation. These ceremonial rituals are intended as signs of respect for the judiciary itself, but perhaps they add to a reputation for haughtiness. In the interest of contributing to the improvement of our reputation, even though that reputation, on balance, is still deservedly good, I will attempt to explain some qualities of judicial modesty and suggest ways of promoting this virtue. Unlike the recent expressions of Chief Justice Roberts and Judge Posner, my perspective does not concern how the Supreme Court should interpret the Constitution. I will leave that important issue to other commentators who already provide it plenty of attention. I will instead apply what both the Chief Justice and Judge Posner have said about the rudiments of judicial modesty to aspects of the federal judiciary that are more parochial. As the most junior member of the Court of Appeals for the Eleventh Circuit, my vantage is not as lofty as others, so my contribution will be, shall I say, more modest. After I provide an overview of judicial modesty based on what the Chief Justice and Judge Posner have said about it, I will address two aspects of my work that provide opportunities to display judicial modesty. First, I will address an aspect of the adjudicative work of the courts of appeals: that is, our orders denying rehearing en banc and the routine practice of filing dissenting opinions to accompany those orders. I will argue that these opinions are inconsistent with judicial modesty. Second, I will address a component of the administrative work of the federal judiciary: that is, our policy about employing either term or career law clerks. I will argue that the policy recently adopted by the Judicial Conference of the United States that limits federal judges to one career clerk is consistent with judicial modest

The Great Writ and Federal Courts: Judge Wood\u27s Solution in Search of a Problem

Judge Diane Wood provides, in her characteristically efficient prose, a thoughtful overview of the history of the Great Writ in service of a thesis that her essay otherwise fails to support. Judge Wood invokes Judge Henry Friendly’s classic article, Is Innocence Irrelevant? Collateral Attack on Criminal Judgments, to suggest that the writ of habeas corpus should be expanded to allow federal courts to review the petitions of state prisoners who allege their actual innocence without otherwise identifying any violation of federal law in securing their convictions. But that thesis cannot be squared with the proposal Judge Friendly championed in his article. Nor is it consistent with the limited jurisdiction of the federal courts. And Judge Wood’s essay fails to make the case for how her proposed expansion of the writ would work or whether it would even likely result in the grant of relief to a substantial number of prisoners whose innocence would otherwise go undetected. If anything, Judge Friendly’s case for restricting the writ remains compelling though unfulfilled

Computerized system for translating a torch head

The system provides a constant travel speed along a contoured workpiece. It has a driven skate characterized by an elongated bed, with a pair of independently pivoted trucks connected to the bed for support. The trucks are mounted on a contoured track of arbitrary configuration in a mutually spaced relation. An axially extensible torch head manipulator arm is mounted on the bed of the carriage and projects perpendicular from the midportion. The torch head is mounted at its distal end. A real-time computerized control drive subsystem is used to advance the skate along the track of a variable rate for maintaining a constant speed for the torch head tip, and to position the torch axis relative to a preset angle to the workpiece

Quantification and propagation of errors when converting vertebrate biomineral oxygen isotope data to temperature for palaeoclimate reconstruction

Oxygen isotope analysis of bioapatite in vertebrate remains (bones and teeth) is commonly used to address questions on palaeoclimate from the Eocene to the recent past. Researchers currently use a range of methods to calibrate their data, enabling the isotopic composition of precipitation and the air temperature to be estimated. In some situations the regression method used can significantly affect the resulting palaeoclimatic interpretations. Furthermore, to understand the uncertainties in the results, it is necessary to quantify the errors involved in calibration. Studies in which isotopic data are converted rarely address these points, and a better understanding of the calibration process is needed. This paper compares regression methods employed in recent publications to calibrate isotopic data for palaeoclimatic interpretation and determines that least-squares regression inverted to x=(y-b)/a is the most appropriate method to use for calibrating causal isotopic relationships. We also identify the main sources of error introduced at each conversion stage, and investigate ways to minimise this error. We demonstrate that larger sample sizes substantially reduce the uncertainties inherent within the calibration process: typical uncertainty in temperature inferred from a single sample is at least ±4°C, which multiple samples can reduce to ±1-2°C. Moreover, the gain even from one to four samples is greater than the gain from any further increases. We also show that when converting δ18Oprecipitation to temperature, use of annually averaged data can give significantly less uncertainty in inferred temperatures than use of monthly rainfall data. Equations and an online spreadsheet for the quantification of errors are provided for general use, and could be extended to contexts beyond the specific application of this paper.Palaeotemperature estimation from isotopic data can be highly informative for our understanding of past climates and their impact on humans and animals. However, for such estimates to be useful, there must be confidence in their accuracy, and this includes an assessment of calibration error. We give a series of recommendations for assessing uncertainty when making calibrations of δ18Obioapatite-δ18Oprecipitation-Temperature. Use of these guidelines will provide a more solid foundation for palaeoclimate inferences made from vertebrate isotopic data.We are grateful to the University of Cambridge (AJEP) and the Royal Society (RES) for financial support