Ballistic one-dimensional holes with strong g-factor anisotropy in germanium

We report experimental evidence of ballistic hole transport in one-dimensional quantum wires gate-defined in a strained SiGe/Ge/SiGe quantum well. At zero magnetic field, we observe conductance plateaus at integer multiples of 2e2/h. At finite magnetic field, the splitting of these plateaus by Zeeman effect reveals largely anisotropic g-factors with absolute values below 1 in the quantum-well plane, and exceeding 10 out-of-plane. This g-factor anisotropy is consistent with a heavy-hole character of the propagating valence-band states, which is in line with a predominant confinement in the growth direction. Remarkably, we observe quantized ballistic conductance in device channels up to 600 nm long. These findings mark an important step toward the realization of novel devices for applications in quantum spintronics

Incidental PET/CT Findings of Suspected COVID-19 in a Region of High Prevalence.

We describe a case of suspected COVID-19 pneumonia in a 61-year-old male with known primary central nervous system diffuse large B-cell lymphoma (DLBCL) who underwent restaging PET/CT during the initial peak of infection of COVID-19 pneumonia within the New York region. At the time of his routine PET-CT to assess for disease progression, typical CT imaging features of COVID-19 pneumonia were identified. Upon further investigation, the patient was asymptomatic, and his infection status remained unknown. He was subsequently lost to follow-up with his COVID-19 status pending

The Economic Implications for Sustainable Mining

This paper will discuss the concept of sustainability in terms of its economic implications, with specific emphasis on the ramifications for the mining sector in Brasil. It will examine this perspective through a review of conceptual approaches to exhaustible resource sustainability and describe its relationship to the more general definition of sustainable development. Additionally, it will offer suggestions of how to operationalize the concept of sustainable development so that the criterion of sustainability can become a real aspect of the decision process

THE ECONOMIC IMPLICATIONS FOR SUSTAINABLE MINING WITHIN THE PARADIGM OF SUSTAINABLE DEVELOPMENT

Este texto visa discutir o conceito de sustentabilidade em termos de suas implicações econômicas, com especial ênfase nas ramificações do setor mineiro no Brasil. Pretende-se examinar esta perspectiva através de uma revisão das abordagens conceituais à sustentabilidade dos recursos exauríveis e descrever sua relação com uma definição geral do desenvolvimento sustentável. Adicionalmente visa-se oferecer sugestões relativas à operacionalização do conceito de desenvolvimento sustentável de modo que o critério de sustentabilidade possa tornar-se um aspecto real do processo decisório.This paper will discuss the concept of sustainability in terms of its economic implications, with specific emphasis on the ramifications for the mining sector in Brasil. It will examine this perspective through a review of conceptual approaches to exhaustible resource sustainability and describe it's relationship to the more general definition of sustainable development. Additionally, it will offer suggestions of how to operationalize the concept of sustainable development so that the criterion of sustainability can become a real aspect of the decision process

CMC Spheres in the Heisenberg Group

We study a family of spheres with constant mean curvature (CMC) in the Riemannian Heisenberg group H1. These spheres are conjectured to be the isoperimetric sets of H1. We prove several results supporting this conjecture. We also focus our attention on the sub-Riemannian limit

Le destin des manuscrits catholiques d’Isaac Papin après sa mort : convoitise et mystère autour de la dépouille intellectuelle d’un sympathisant janséniste

Isaac Papin (1657-1709), né calviniste, est passé à la postérité pour sa conversion au catholicisme. Après avoir été le fer de lance des pajonistes au sein du Refuge, il se convertit entre les mains de Bossuet, en 1690. La seconde partie de sa vie est beaucoup moins connue. Deux dossiers de la collection Port-Royal d’Utrecht permettent de lever le voile sur un aspect totalement inédit de son parcours : ses relations avec le milieu janséniste. Si les traces sont peu nombreuses, ses relations avec Pasquier Quesnel sont attestées. Après sa mort, ses manuscrits sont convoités et finalement récupérés par les jansénistes. Les textes qu’ils contiennent sont publiés par les soins de Quesnel, en 1713, sous le titre Les deux voies opposées en matière de religion

Double connective tissue graft to treat deep coronal-radicular abrasion: A 19-year follow-up case report

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170298/1/cap10176.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/170298/2/cap10176_am.pd

A CMOS silicon spin qubit

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot (QD) encoding a hole spin qubit, the second one a QD used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. Our result opens a viable path to qubit up-scaling through a readily exploitable CMOS platform.Comment: 12 pages, 4 figure

On the Iteration Complexity of Hypergradient Computation

We study a general class of bilevel problems, consisting in the minimization of an upper-level objective which depends on the solution to a parametric fixed-point equation. Important instances arising in machine learning include hyperparameter optimization, meta-learning, and certain graph and recurrent neural networks. Typically the gradient of the upper-level objective (hypergradient) is hard or even impossible to compute exactly, which has raised the interest in approximation methods. We investigate some popular approaches to compute the hypergradient, based on reverse mode iterative differentiation and approximate implicit differentiation. Under the hypothesis that the fixed point equation is defined by a contraction mapping, we present a unified analysis which allows for the first time to quantitatively compare these methods, providing explicit bounds for their iteration complexity. This analysis suggests a hierarchy in terms of computational efficiency among the above methods, with approximate implicit differentiation based on conjugate gradient performing best. We present an extensive experimental comparison among the methods which confirm the theoretical findings