L^p(R^n)-continuity of translation invariant anisotropic pseudodifferential operators: a necessary condition

We consider certain anisotropic translation invariant pseudodifferential operators, belonging to a class denoted by $\mathrm{op}(\mathcal{M}^{\lambda}_{\psi})$, where $\lambda$ and $\psi=(\psi_1,\dots,\psi_n)$ are the "order" and "weight" functions, defined on $\mathbb{R}^n$, for the corresponding space of symbols. We prove that the boundedness of a suitable function $F_p\colon\mathbb{R}^n\to[0,+\infty)$, $1<p<\infty$, associated with $\lambda$ and $\psi$, is necessary to let every element of $\mathrm{op}(\mathcal{M}^{\lambda}_{\psi})$ be a $L^p(\mathbb{R}^n)$-multiplier. Additionally, we show that some results known in the literature can be recovered as special cases of our necessary condition.Comment: 16 pages, mistakes and typos correctio

When Ebola Came to Canada: Race and the Making of the Respectable Body

This paper examines the way in which the recent Ebola media spectacle in Canada relied upon spatial delineations of race and degeneracy. I argue that the representation of immigrants as vectors of disease is a useful and coercive tool in the project of justifying immigration reform and the state control of racial bodies.Cet article etudie la facon dont le recent spectacle cree par les medias au Canada au sujet du virus Ebola se fiait aux delineations spatiales de la race et de la degenerescence. Je denote que la representation des immigrants comme vecteurs de maladies est un outil utile et cohesif dans le projet de la justification de la reforme de l'immigration et le controle que l'etat a sur les masses raciales

Content addressable memory project

The progress on the Rutgers CAM (Content Addressable Memory) Project is described. The overall design of the system is completed at the architectural level and described. The machine is composed of two kinds of cells: (1) the CAM cells which include both memory and processor, and support local processing within each cell; and (2) the tree cells, which have smaller instruction set, and provide global processing over the CAM cells. A parameterized design of the basic CAM cell is completed. Progress was made on the final specification of the CPS. The machine architecture was driven by the design of algorithms whose requirements are reflected in the resulted instruction set(s). A few of these algorithms are described

A surge of late-occurring meiotic double-strand breaks rescues synapsis abnormalities in spermatocytes of mice with hypomorphic expression of SPO11

Meiosis is the biological process that, after a cycle of DNA replication, halves the cellular chromosome complement, leading to the formation of haploid gametes. Haploidization is achieved via two successive rounds of chromosome segregation, meiosis I and II. In mammals, during prophase of meiosis I, homologous chromosomes align and synapse through a recombination-mediated mechanism initiated by the introduction of DNA double-strand breaks (DSBs) by the SPO11 protein. In male mice, if SPO11 expression and DSB number are reduced below heterozygosity levels, chromosome synapsis is delayed, chromosome tangles form at pachynema, and defective cells are eliminated by apoptosis at epithelial stage IV at a spermatogenesis-specific endpoint. Whether DSB levels produced in Spo11 +/− spermatocytes represent, or approximate, the threshold level required to guarantee successful homologous chromosome pairing is unknown. Using a mouse model that expresses Spo11 from a bacterial artificial chromosome, within a Spo11 −/− background, we demonstrate that when SPO11 expression is reduced and DSBs at zygonema are decreased (approximately 40 % below wild-type level), meiotic chromosome pairing is normal. Conversely, DMC1 foci number is increased at pachynema, suggesting that under these experimental conditions, DSBs are likely made with delayed kinetics at zygonema. In addition, we provide evidences that when zygotene-like cells receive enough DSBs before chromosome tangles develop, chromosome synapsis can be completed in most cells, preventing their apoptotic elimination

A perturbed MicroRNA expression pattern characterizes embryonic neural stem cells derived from a severe mouse model of spinal muscular atrophy (SMA)

Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder and the leading genetic cause of death in infants. Despite the disease-causing gene, survival motor neuron (SMN1), encodes a ubiquitous protein, SMN1 deficiency preferentially affects spinal motor neurons (MNs), leaving the basis of this selective cell damage still unexplained. As neural stem cells (NSCs) are multipotent self-renewing cells that can differentiate into neurons, they represent an in vitro model for elucidating the pathogenetic mechanism of neurodegenerative diseases such as SMA. Here we characterize for the first time neural stem cells (NSCs) derived from embryonic spinal cords of a severe SMNΔ7 SMA mouse model. SMNΔ7 NSCs behave as their wild type (WT) counterparts, when we consider neurosphere formation ability and the expression levels of specific regional and self-renewal markers. However, they show a perturbed cell cycle phase distribution and an increased proliferation rate compared to wild type cells. Moreover, SMNΔ7 NSCs are characterized by the differential expression of a limited number of miRNAs, among which miR-335-5p and miR-100-5p, reduced in SMNΔ7 NSCs compared to WT cells. We suggest that such miRNAs may be related to the proliferation differences characterizing SMNΔ7 NSCs, and may be potentially involved in the molecular mechanisms of SMA

A surge of late-occurring meiotic double-strand breaks rescues synapsis abnormalities in spermatocytes of mice with hypomorphic expression of SPO11

Meiosis is the biological process that, after a cycle of DNA replication, halves the cellular chromosome complement, leading to the formation of haploid gametes. Haploidization is achieved via two successive rounds of chromosome segregation, meiosis I and II. In mammals, during prophase of meiosis I, homologous chromosomes align and synapse through a recombination-mediated mechanism initiated by the introduction of DNA double-strand breaks (DSBs) by the SPO11 protein. In male mice, if SPO11 expression and DSB number are reduced below heterozygosity levels, chromosome synapsis is delayed, chromosome tangles form at pachynema, and defective cells are eliminated by apoptosis at epithelial stage IV at a spermatogenesis-specific endpoint. Whether DSB levels produced in Spo11 (+/-) spermatocytes represent, or approximate, the threshold level required to guarantee successful homologous chromosome pairing is unknown. Using a mouse model that expresses Spo11 from a bacterial artificial chromosome, within a Spo11 (-/-) background, we demonstrate that when SPO11 expression is reduced and DSBs at zygonema are decreased (approximately 40 % below wild-type level), meiotic chromosome pairing is normal. Conversely, DMC1 foci number is increased at pachynema, suggesting that under these experimental conditions, DSBs are likely made with delayed kinetics at zygonema. In addition, we provide evidences that when zygotene-like cells receive enough DSBs before chromosome tangles develop, chromosome synapsis can be completed in most cells, preventing their apoptotic elimination

Sistema de seguimiento solar para paneles fotovoltaicos

El objetivo del presente trabajo es desarrollar un seguidor solar de dos ejes para ser aplicado a panales fotovoltaicos. Esta aplicación permite que el panel incremente su producción en un 20 a 30%, dependiendo del mes y la hora del día. El sistema desarrollado contempla 5 modos de funcionamiento. Se utilizó una placa Arduino Mega ya que esta satisface los requerimientos de memoria y potencia de cálculo requeridos. Se usaron sensores LDR para el posicionamiento; además, el sistema contempla la posibilidad de conectarse mediante telefonía celular. Para el modelo a escala se usaron servomotores marca Tower Pro modelo SG90 por sus bajos requerimientos energéticos que permiten modularizar el sistema. Se realizaron simulaciones donde el error resultante es inferior al 1% para el posicionamiento y el aumento de energía producida está dentro de los valores esperados. Se proponen mejoras en el software de manera de hacerlo más accesible.The objective of the present work is to develop a two axis solar tracker to be applied to photovoltaic panels. This application allows the panel to increase its production by 20 to 30%, depending on the month and the time of day. The developed system contemplates 5 modes of operation. An Arduino Mega board was used as it satisfies the required memory and computing power requirements. LDR sensors were used for positioning; In addition, the system contemplates the possibility of connecting by cellular telephony. For the scale model, a Tower Pro model SG90 servomotors are used for their low energy requirements that allow modularizing the system. Simulations were carried out where the error was less than 1% for the positioning and the increase of the energy produced within the expected values. Improvements are proposed in the software in order to make it more accessible.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Sistema de seguimiento solar para paneles fotovoltaicos

El objetivo del presente trabajo es desarrollar un seguidor solar de dos ejes para ser aplicado a panales fotovoltaicos. Esta aplicación permite que el panel incremente su producción en un 20 a 30%, dependiendo del mes y la hora del día. El sistema desarrollado contempla 5 modos de funcionamiento. Se utilizó una placa Arduino Mega ya que esta satisface los requerimientos de memoria y potencia de cálculo requeridos. Se usaron sensores LDR para el posicionamiento; además, el sistema contempla la posibilidad de conectarse mediante telefonía celular. Para el modelo a escala se usaron servomotores marca Tower Pro modelo SG90 por sus bajos requerimientos energéticos que permiten modularizar el sistema. Se realizaron simulaciones donde el error resultante es inferior al 1% para el posicionamiento y el aumento de energía producida está dentro de los valores esperados. Se proponen mejoras en el software de manera de hacerlo más accesible.The objective of the present work is to develop a two axis solar tracker to be applied to photovoltaic panels. This application allows the panel to increase its production by 20 to 30%, depending on the month and the time of day. The developed system contemplates 5 modes of operation. An Arduino Mega board was used as it satisfies the required memory and computing power requirements. LDR sensors were used for positioning; In addition, the system contemplates the possibility of connecting by cellular telephony. For the scale model, a Tower Pro model SG90 servomotors are used for their low energy requirements that allow modularizing the system. Simulations were carried out where the error was less than 1% for the positioning and the increase of the energy produced within the expected values. Improvements are proposed in the software in order to make it more accessible.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Expression analysis of miRNA hsa-let7b-5p in naso-oropharyngeal swabs of COVID-19 patients supports its role in regulating ACE2 and DPP4 receptors

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the novel coronavirus responsible for worldwide coronavirus disease (COVID-19). We previously observed that Angiotensin-converting enzyme 2 (ACE2) and Dipeptidyl peptidase-4 (DPP4) are significantly overexpressed in naso-oropharyngeal swabs (NPS) of COVID-19 patients, suggesting their putative functional role in the disease progression. ACE2 and DPP4 overexpression in COVID-19 patients may be associated to epigenetic mechanism, such as miRNA differential expression. We investigated if hsa-let7b-5p, reported to target both ACE2 and DPP4 transcripts, could be involved in the regulation of these genes. We verified that the inhibition and overexpression of hsa-let7b-5p matched to a modulation of both ACE2 and DPP4 levels. Then, we observed a statistically significant downregulation (FC = -1.5; p &lt; 0.05) of hsa-let7b-5p in the same COVID-19 and control samples of our previous study. This is the first study that shows hsa-let7b-5p low expression in naso-oropharyngeal swabs of COVID-19 patients and demonstrates a functional role of this miR in regulating ACE2 and DPP4 levels. These data suggest the involvement of hsa-let7b-5p in the regulation of genes necessary for SARS-CoV-2 infections and its putative role as a therapeutic target for COVID-19

Two Different Therapeutic Approaches for SARS-CoV-2 in hiPSCs-Derived Lung Organoids

The global health emergency for SARS-CoV-2 (COVID-19) created an urgent need to develop new treatments and therapeutic drugs. In this study, we tested, for the first time on human cells, a new tetravalent neutralizing antibody (15033-7) targeting Spike protein and a synthetic peptide homologous to dipeptidyl peptidase-4 (DPP4) receptor on host cells. Both could represent powerful immunotherapeutic candidates for COVID-19 treatment. The infection begins in the proximal airways, namely the alveolar type 2 (AT2) cells of the distal lung, which express both ACE2 and DPP4 receptors. Thus, to evaluate the efficacy of both approaches, we developed three-dimensional (3D) complex lung organoid structures (hLORGs) derived from human-induced pluripotent stem cells (iPSCs) and resembling the in vivo organ. Afterward, hLORGs were infected by different SARS-CoV-2 S pseudovirus variants and treated by the Ab15033-7 or DPP4 peptide. Using both approaches, we observed a significant reduction of viral entry and a modulation of the expression of genes implicated in innate immunity and inflammatory response. These data demonstrate the efficacy of such approaches in strongly reducing the infection efficiency in vitro and, importantly, provide proof-of-principle evidence that hiPSC-derived hLORGs represent an ideal in vitro system for testing both therapeutic and preventive modalities against COVID-19