Report of the x ray and gamma ray sensors panel

Overall five major areas of technology are recommended for development in order to meet the science requirements of the Astrotech 21 mission set. These are: detectors for high resolution gamma ray spectroscopy, cryogenic detectors for improved x ray spectral and spatial resolution, advanced x ray charge coupled devices (CCDs) for higher energy resolution and larger format, extension to higher energies, liquid and solid position sensitive detectors for improving stopping power in the energy range 5 to 500 keV and 0.2 to 2 MeV. Development plans designed to achieve the desired capabilities on the time scales required by the technology freeze dates have been recommended in each of these areas

Design of Optical/IR Blocking Filters for the Lynx X-Ray Microcalorimeter

The Lynx mission concept, under development ahead of the 2020 Astrophysics Decadal Review, includes the Lynx X-ray Microcalorimeter (LXM) as one of its primary instruments. The LXM uses a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.2 to 15 keV) with exquisite angular resolution. Similar to other x-ray microcalorimeters, the LXM uses a set of blocking filters mounted within the dewar that pass the photons of interest (x-rays) while attenuating the out-of-band long-wavelength radiation. Such filters have been successfully used on previous orbital and suborbital instruments; however, the Lynx science objectives, which emphasize observations in the soft x-ray band (<1keV), pose more challenging requirements on the set of LXM blocking filters. We present an introduction to the design of the LXM optical/IR blocking filters and discuss recent advances in filter capability targeted at LXM. In addition, we briefly describe the external filters and the modulated x-ray sources to be used for onboard detector calibration

Making Good Lawyers

Today, the criticism of law schools has become an industry. Detractors argue that legal education fails to effectively prepare students for the practice of law, that it is too theoretical and detached from the profession, that it dehumanizes and alienates students, too expensive and inapt in helping students develop a sense of professional identity, professional values, and professionalism. In this sea of criticisms it is hard to see the forest from the trees. “There is so much wrong with legal education today,” writes one commentator, “that it is hard to know where to begin.” This article argues that any reform agenda will fall short if it does not start by recognizing the dominant influence of the culture of autonomous self-interest in legal education. Law schools engage in a project of professional formation and instill a very particular brand of professional identity. They educate students to become autonomously self-interested lawyers who see their clients and themselves as pursuing self-interest as atomistic actors. As a result, they understand that their primary role is to serve as neutral partisans who promote the narrow self-interest of clients without regard to the interests of their families, neighbors, colleagues, or communities and to the exclusion of counseling clients on the implications of those interests. They view as marginal their roles as an officer of the legal system and as a public citizen and accordingly place a low priority on traditional professional values, such as the commitment to the public good, that conflict with their primary allegiance to autonomous self-interest. In this work of professional formation, law schools are reflecting the values and commitments of the autonomously self-interested culture that is dominant in the legal profession. Therefore, even if law schools sought to form a professional identity outside of the mold of autonomous self-interest, such a commitment would require much more than curricular reform. It would, at minimum, require the construction of a persuasive alternative understanding of the lawyer’s role. The article seeks to offer such an understanding grounded in a relational perspective on lawyers and clients. Part I offers workable definitions of professionalism and professional identity that enable an informed discussion of the formation of professional identity in and by law schools. Part II explores what and how legal education teaches students showing that both institutionally (at the law school level) and individually (at the law professor level) legal education is proactively engaged in the formation of a professional identity of autonomous self-interest. Part II further explains that its dominance in legal education notwithstanding, autonomous self-interest is but one, often unpersuasive, account of professionalism and professional identity. Part III turns to the competing vision of relationally self-interested professionalism and professional identity and develops an outline for legal education grounded in these conceptions. Because legal education reflects a deep commitment to the dominant culture of autonomous self-interest, it is unlikely that reform proposals that are inconsistent with that culture are likely to succeed in the near future. Yet proposing an alternative account of professional identity that exposes the assumptions of the dominant culture, explains their limitations, and develops a more persuasive understanding is a necessary step toward providing a workable framework for reformers committed to promoting professional values in the long term

An X-ray view of the hot circum-galactic medium

The hot circum- galactic medium (CGM) represents the hot gas distributed beyond the stellar content of the galaxies while typically within their dark matter halos. It serves as a depository of energy and metal- enriched materials from galactic feedback and a reservoir from which the galaxy acquires fuels to form stars. It thus plays a critical role in the coevolution of galaxies and their environments. X- rays are one of the best ways to trace the hot CGM. I will briefly review what we have learned about the hot CGM based on X- ray observations over the past two decades, and what we still do not know. I will also briefly prospect what may be the foreseeable breakthrough in the next one or two decades with future X- ray missions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154643/1/asna202023775.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154643/2/asna202023775_am.pd

Novel cruzain inhibitors for the treatment of Chagas' disease.

The protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas' disease, affects millions of individuals and continues to be an important global health concern. The poor efficacy and unfavorable side effects of current treatments necessitate novel therapeutics. Cruzain, the major cysteine protease of T. cruzi, is one potential novel target. Recent advances in a class of vinyl sulfone inhibitors are encouraging; however, as most potential therapeutics fail in clinical trials and both disease progression and resistance call for combination therapy with several drugs, the identification of additional classes of inhibitory molecules is essential. Using an exhaustive virtual-screening and experimental validation approach, we identify several additional small-molecule cruzain inhibitors. Further optimization of these chemical scaffolds could lead to the development of novel drugs useful in the treatment of Chagas' disease

Seismic Safety Retrofit of Second Narrows Bridge Foundations Geotechnical Design Aspects

The geotechnical engineering analyses carried out for the seismic safety retrofit design of Second Narrows Bridge located in Vancouver, Canada, are presented. The work involved detailed ground response analyses to evaluate the liquefaction potential of site soils, the development of a series of numerical models to assess the pattern and magnitude of liquefaction-induced ground displacements, and to analytically evaluate the ground displacements with potential ground improvements

Coupling nonpolar and polar solvation free energies in implicit solvent models

Recent studies on the solvation of atomistic and nanoscale solutes indicate that a strong coupling exists between the hydrophobic, dispersion, and electrostatic contributions to the solvation free energy, a facet not considered in current implicit solvent models. We suggest a theoretical formalism which accounts for coupling by minimizing the Gibbs free energy of the solvent with respect to a solvent volume exclusion function. The resulting differential equation is similar to the Laplace-Young equation for the geometrical description of capillary interfaces, but is extended to microscopic scales by explicitly considering curvature corrections as well as dispersion and electrostatic contributions. Unlike existing implicit solvent approaches, the solvent accessible surface is an output of our model. The presented formalism is illustrated on spherically or cylindrically symmetrical systems of neutral or charged solutes on different length scales. The results are in agreement with computer simulations and, most importantly, demonstrate that our method captures the strong sensitivity of solvent expulsion and dewetting to the particular form of the solvent-solute interactions.Comment: accpted in J. Chem. Phy

The Implementation of the Colored Abstract Simplicial Complex and its Application to Mesh Generation

We introduce CASC: a new, modern, and header-only C++ library which provides a data structure to represent arbitrary dimension abstract simplicial complexes (ASC) with user-defined classes stored directly on the simplices at each dimension. This is accomplished by using the latest C++ language features including variadic template parameters introduced in C++11 and automatic function return type deduction from C++14. Effectively CASC decouples the representation of the topology from the interactions of user data. We present the innovations and design principles of the data structure and related algorithms. This includes a metadata aware decimation algorithm which is general for collapsing simplices of any dimension. We also present an example application of this library to represent an orientable surface mesh.Comment: 24 pages, 6 figure

Adaptive Accelerated Molecular Dynamics (Ad-AMD) Revealing the Molecular Plasticity of P450cam

An extended accelerated molecular dynamics (AMD) methodology called adaptive AMD is presented. Adaptive AMD (Ad-AMD) is an efficient and robust conformational space sampling algorithm that is particularly-well suited to proteins with highly structured potential energy surfaces exhibiting complex, large-scale collective conformational transitions. Ad-AMD simulations of substrate-free P450cam reveal that this system exists in equilibrium between a fully and partially open conformational state. The mechanism for substrate binding depends on the size of the ligand. Larger ligands enter the P450cam binding pocket, and the resulting substrate-bound system is trapped in an open conformation via a population shift mechanism. Small ligands, which fully enter the binding pocket, cause an induced-fit mechanism, resulting in the formation of an energetically stable closed conformational state. These results are corroborated by recent experimental studies and potentially provide detailed insight into the functional dynamics and conformational behavior of the entire cytochrome-P450 superfamily