Lorenz-Mie scattering of focused light via complex focus fields: an analytic treatment

The Lorenz-Mie scattering of a wide class of focused electromagnetic fields off spherical particles is studied. The focused fields in question are constructed through complex focal displacements, leading to closed-form expressions that can exhibit several interesting physical properties, such as orbital and/or spin angular momentum, spatially-varying polarization, and a controllable degree of focusing. These fields constitute complete bases that can be considered as nonparaxial extensions of the standard Laguerre-Gauss beams and the recently proposed polynomials-of-Gaussians beams. Their analytic form turns out to lead also to closed-form expressions for their multipolar expansion. Such expansion can be used to compute the field scattered by a spherical particle and the resulting forces and torques exerted on it, for any relative position between the field's focus and the particle.Comment: 11 pages, 7 figure

Who Participates? Who Leads? What are the Outcomes for College Students in Co-Curricular Activities?

Sessa and London\u27s learning model (Sessa & London 2006, London & Sessa, 2006) was used to generate hypotheses suggesting that readiness to learn predicts which college students chose to respond to learning triggers in the institutional context of a university (i.e. co- or extra-curricular activities, take on leader roles) and that participation leads to such learning outcomes as higher GP A, psycho-social development, and flourishing/wellbeing. One-hundred and sixty-eight students who varied in their participation levels (no participation beyond the classroom, participation in co-curricular activities, clubs, sports, etc., and involved in leader roles) filled out an online survey. Results partially support hypotheses. Readiness to learn partially predicted which students held leader positions and which did not participate in activities beyond the classroom; readiness to learn did not predict which students participated but did not hold leader positions. Leaders differed from non-participants in psycho-social development and flourishing. Few differences were found between leaders and participants, or participants and non-participants

A Rapid and Sensitive High – Throughput Screening Method to Identify Compounds Targeting Protein-Nucleic Acids Interactions

DNA-binding and RNA-binding proteins are usually considered ‘undruggable’ partly due to the lack of an efficient method to identify inhibitors from existing small molecule repositories. Here we report a rapid and sensitive high-throughput screening approach to identify compounds targeting protein–nucleic acids interactions based on protein–DNA or protein–RNA interaction enzyme-linked immunosorbent assays (PDI-ELISA or PRI-ELISA). We validated the PDI-ELISA method using the mammalian highmobility- group protein AT-hook 2 (HMGA2) as the protein of interest and netropsin as the inhibitor of HMGA2–DNA interactions. With this method we successfully identified several inhibitors and an activator for HMGA2–DNA interactions from a collection of 29 DNA-binding compounds. Guided by this screening excise, we showed that netropsin, the specific inhibitor of HMGA2–DNA interactions, strongly inhibited the differentiation of the mouse pre-adipocyte 3T3-L1 cells into adipocytes, most likely through a mechanism by which the inhibition is through preventing the binding of HMGA2 to the target DNA sequences. This method should be broadly applicable to identify compounds or proteins modulating many DNA-binding or RNA-binding proteins

Strengthening weak measurements of qubit out-of-time-order correlators

For systems of controllable qubits, we provide a method for experimentally obtaining a useful class of multitime correlators using sequential generalized measurements of arbitrary strength. Specifically, if a correlator can be expressed as an average of nested (anti)commutators of operators that square to the identity, then that correlator can be determined exactly from the average of a measurement sequence. As a relevant example, we provide quantum circuits for measuring multiqubit out-of-time-order correlators using optimized control-Z or ZX-90 two-qubit gates common in superconducting transmon implementations.Comment: 12 pages, 6 figures, published versio

On the isotropy constant of random polytopes

Let X 1 , . . . , X N be independent random vectors uniformly distributed on an isotropic convex body K ¿ Rn , and let KN be the symmetric convex hull of Xi’s. We show that with high probability LKN = C log(2N/n), where C is an absolute constant. This result closes the gap in known estimates in the range Cn = N = n1+d. Furthermore, we extend our estimates to the symmetric convex hulls of vectors y1 X1, . . . , yN X N , where y = (y1, . . . , yN ) is a vector in RN . Finally, we discuss the case of a random vector y

A rapid and sensitive high-throughput screening method to identify compounds targeting protein-nucleic acids interactions

DNA-binding and RNA-binding proteins are usually considered ‘undruggable’ partly due to the lack of an efficient method to identify inhibitors from existing small molecule repositories. Here we report a rapid and sensitive high-throughput screening approach to identify compounds targeting protein– nucleic acids interactions based on protein–DNA or protein–RNA interaction enzyme-linked immunosorbent assays (PDI-ELISA or PRI-ELISA). We validated the PDI-ELISA method using the mammalian highmobility- group protein AT-hook 2 (HMGA2) as the protein of interest and netropsin as the inhibitor of HMGA2–DNA interactions. With this method we successfully identified several inhibitors and an activator for HMGA2–DNA interactions from a collection of 29 DNA-binding compounds. Guided by this screening excise, we showed that netropsin, the specific inhibitor of HMGA2–DNA interactions, strongly inhibited the differentiation of the mouse pre-adipocyte 3T3-L1 cells into adipocytes, most likely through a mechanism by which the inhibition is through preventing the binding of HMGA2 to the target DNA sequences. This method should be broadly applicable to identify compounds or proteins modulating many DNA-binding or RNA-binding proteins

Out-of-Time-Ordered-Correlator Quasiprobabilities Robustly Witness Scrambling

Out-of-time-ordered correlators (OTOCs) have received considerable recent attention as qualitative witnesses of information scrambling in many-body quantum systems. Theoretical discussions of OTOCs typically focus on closed systems, raising the question of their suitability as scrambling witnesses in realistic open systems. We demonstrate empirically that the nonclassical negativity of the quasiprobability distribution (QPD) behind the OTOC is a more sensitive witness for scrambling than the OTOC itself. Nonclassical features of the QPD evolve with timescales that are robust with respect to decoherence and are immune to false positives caused by decoherence. To reach this conclusion, we numerically simulate spin-chain dynamics and three measurement protocols (the interferometric, quantum-clock, and weak-measurement schemes) for measuring OTOCs. We target experiments based on quantum-computing hardware such as superconducting qubits and trapped ions

Out-of-Time-Ordered-Correlator Quasiprobabilities Robustly Witness Scrambling

Out-of-time-ordered correlators (OTOCs) have received considerable recent attention as qualitative witnesses of information scrambling in many-body quantum systems. Theoretical discussions of OTOCs typically focus on closed systems, raising the question of their suitability as scrambling witnesses in realistic open systems. We demonstrate empirically that the nonclassical negativity of the quasiprobability distribution (QPD) behind the OTOC is a more sensitive witness for scrambling than the OTOC itself. Nonclassical features of the QPD evolve with timescales that are robust with respect to decoherence and are immune to false positives caused by decoherence. To reach this conclusion, we numerically simulate spinchain dynamics and three measurement protocols (the interferometric, quantum-clock, and weakmeasurement schemes) for measuring OTOCs. We target experiments based on quantum-computing hardware such as superconducting qubits and trapped ions

COVID-19: un nuevo reto para la cadena de suministro

El objetivo de este artículo es identificar las tendencias, las estrategias, las acciones utilizadas frente al covid-19 y los impactos negativos en la cadena de suministro mediante una revisión de literatura y una entrevista con un experto de la materia. En la actualidad se le conoce a la cadena de suministros como el conjunto de procesos involucrados en el flujo de un producto que llega al consumidor final, abarcando aspectos como la planeación, almacenamiento, distribución, entre otros; sin embargo, esta definición ha ido evolucionando a lo largo de los años, más aún con la pandemia su concepto se redefine e incorpora nuevos tópicos, situando a la presente investigación un carácter informativo, preventivo e indicativo para la formulación de planes estratégicos y planes de acción mediante el benchmarking. Con este fin se desarrolla una introducción temática y una exposición de buenas prácticas mediante el estado de arte. Asimismo, se incorpora una base teórica con la finalidad de guiar al lector sobre la investigación por medio de las evidencias más relevantes encontradas en artículos con temáticas similares como conceptos de la cadena de suministro y problemáticas. Los resultados se agruparon en temas como compras, almacenamiento, distribución, abastecimiento y aspectos generales. Finalmente, se desarrolla la discusión sobre los hallazgos presentados y las conclusiones pertinentes.The objective of this article is to identify trends, strategies, actions used against COVID 19 and negative impacts on the supply chain through a literature review and an interview with an expert in the field. At present, the supply chain is known as the set of processes involved in the flow of a product that reaches the final consumer, covering aspects such as planning, storage, distribution, among others; However, this definition has evolved over the years, even more so with the pandemic, its concept is redefined and incorporates new topics, making this research informative, preventive and indicative for the formulation of strategic plans and plans of action through benchmarking. To this end, a thematic introduction and an exhibition of good practices through the state of the art is developed. Likewise, a theoretical base is incorporated in order to guide the reader on the investigation through the most relevant evidence found in articles with similar topics such as supply chain concepts and problems. The results were grouped into topics such as purchasing, storage, distribution, supply and general aspects. Finally, the discussion on the presented findings and the pertinent conclusions is develope