528 research outputs found

    Nasa desalting kit development, phase ii first progress report

    Get PDF
    NASA desalting kit development - container and processor desig

    There goes the Berimbau: An Africa-Brazil-Germany Musician-Body Trajectory

    Get PDF
    This article presents the partial results of a dissertation entitled The role of music in the internationalization of capoeira: Flows and crossroads Rio-France-Germany (2022). Documents prepared by practitioners of the N'Zinga Capoeira School in Hanover, Germany, published on a platform called Yumpu, provide information on how musical-cultural knowledge of capoeira is understood and passed down in this context. Through the translation of songs and the study of informational texts written by German instructors about capoeira, I observe that musicality (and, by extension, corporeality) are fundamenatal to the consolidation of capoeira culture in Germany. This analysis is influenced by Leda Martins' Performances da Oralitura (2003), which highlights the enduring African root in Afro-diasporic cultural activities, transmitting africanidades ("Africanities") beyond the performance itself. Paul Gilroy's The Black Alantic (1993) also informed my understanding of the relevance of Black culture in critiques of European democracy. German capoeira practitioners gain a deeper understanding of the structural differences imposed on racialized people when they coexist with their mestres and learn of oppression and social difference through the art of capoeira.

    Data-Driven Equation Discovery of a Cloud Cover Parameterization

    Full text link
    A promising method for improving the representation of clouds in climate models, and hence climate projections, is to develop machine learning-based parameterizations using output from global storm-resolving models. While neural networks can achieve state-of-the-art performance within their training distribution, they can make unreliable predictions outside of it. Additionally, they often require post-hoc tools for interpretation. To avoid these limitations, we combine symbolic regression, sequential feature selection, and physical constraints in a hierarchical modeling framework. This framework allows us to discover new equations diagnosing cloud cover from coarse-grained variables of global storm-resolving model simulations. These analytical equations are interpretable by construction and easily transferable to other grids or climate models. Our best equation balances performance and complexity, achieving a performance comparable to that of neural networks (R2=0.94R^2=0.94) while remaining simple (with only 11 trainable parameters). It reproduces cloud cover distributions more accurately than the Xu-Randall scheme across all cloud regimes (Hellinger distances <0.09<0.09), and matches neural networks in condensate-rich regimes. When applied and fine-tuned to the ERA5 reanalysis, the equation exhibits superior transferability to new data compared to all other optimal cloud cover schemes. Our findings demonstrate the effectiveness of symbolic regression in discovering interpretable, physically-consistent, and nonlinear equations to parameterize cloud cover.Comment: 35 pages, 10 figures, Submitted to 'Journal of Advances in Modeling Earth Systems' (JAMES

    HIV-1 Immune Escape and Neutralizing Antibodies : Solid Phase Proteoliposomes Containing HIV-1 Envelope Glycoproteins as Antigens and Immunogens and HIV-1 Core Envelope Glycoproteins Deficient in T-Helper Epitopes

    Get PDF
    The HIV-1 envelope glycoproteins gp120 and gp41 mediate binding and fusion of the virus to target cells. The envelope glycoproteins are exposed on the surface of the virus as trimeric spikes and are the major targets for neutralizing antibodies. The design of envelope glycoprotein-based subunit vaccines has been frustrated by many viral immune escape mechanisms. Trimeric envelope glycoprotein formulations hold promise to overcome limitations of monomeric envelope glycoproteins as immunogens. The generation of native, trimeric envelope glycoprotein complexes, however, remains a major challenge. Here, solid-phase proteoliposomes containing native, trimeric HIV-1 envelope glycoprotein complexes that mimic the trimeric complex as it is found on the viral surface have been designed. In a comparative immunogenicity study, these proteoliposomes were shown to better elicit broadly neutralizing antibodies than gp120. A second trimeric envelope glycoprotein formulation, soluble YU2 gp140-GCN4 constructs, were also shown to better elicit broadly neutralizing antibodies in rabbits, extending a previous study in mice. These data support the hypothesis that trimeric envelope glycoprotein formulations are an advance over gp120-based immunogens. To date, only four broadly neutralizing antibodies against the HIV-1 envelope glycoproteins have been identified. Here, three novel Fab antibody fragments binding to the CD4 binding site of gp120 have been identified from phage-displayed antibody libraries with proteoliposomes. These Fab antibodies display some breadth and potency in neutralizing HIV-1. Comparison of the neutralizing activity of Fab antibodies and whole antibodies directed to the CD4 binding site suggests that these Fab antibodies may significantly gain neutralizing potency as whole antibodies. Many HIV-1 immune escape mechanisms complicate the elicitation of broadly neutralizing antibodies. Core gp120 envelope glycoproteins derived from primary isolate viruses were found to be deficient in T-helper epitopes. This finding is suggestive of yet another HIV-1 viral immune escape mechanism, the escape from recognition by CD4+ T-helper cells

    THE INFLUENCE OF THE PARTNER CELL ON THE PRODUCTION OF L VIRUS AND THE EXPRESSION OF VIRAL SURFACE ANTIGEN IN HYBRID CELLS

    Get PDF
    The C-type particles produced by the A9 and A9HT sublines of mouse L cells were shown to infect C3H (N type), but not C57BL (B type), mouse embryo fibroblasts. Infection was indicated by distinct single giant cell formation in the XC monolayer used to overlay the mouse embryo fibroblasts. On the basis of these results it was concluded that the L cell virus is N tropic. A9 and A9HT cells were fused to various mouse cells derived from tumors and normal tissues. The ability to produce the Moloney-type surface antigen and to release infectious virus was introduced by the A9 component into the hybrid cell. Virus production, measured by antigen induction on JLS-V9 cells, was suppressed in those hybrids in which the partner cell had a genotype determining low infectibility with that particular virus (B-type cell). It thus appears that the major genetic locus affecting resistance to infection with leukemia viruses, the Fv-1 locus, regulates infectious virus production in somatic cell hybrids also. The same genetic locus did not seem to govern the expression of all virus-related functions, for the virus-determined membrane antigen was demonstrated in many of the N x B-type hybrids in which production of infectious virus was suppressed

    LACK OF DISTINCTIVE SURFACE ANTIGEN ON CELLS TRANSFORMED BY MURINE SARCOMA VIRUS

    Get PDF
    Some murine sarcoma virus (MSV)-transformed mouse 3T3 cells contain the MSV genome in the absence of infectious helper murine leukemia virus (MuLV) and MSV production. These cells, designated S+L- (sarcoma positive, leukemia negative), were analyzed for the presence of a possible MSV-determined membrane antigen by the mixed hemadsorption test and in vitro lymphocyte cytotoxicity assay. Two different serological approaches were used: (a) isoantibody-free sera were obtained by immunizing with MSV of syngeneic origin or by allowing primary, autologous MSV sarcomas to regress, or (b) alloantisera obtained by immunizing C57BL mice with S+L- cells were absorbed with the corresponding nontransformed 3T3 cells until all activity against 3T3 had been removed. While MuLV-superinfected S+L- cells and a culture line of an MSV sarcoma known to produce both MSV and MLV were highly reactive, normal 3T3 and S+L- cells were negative. Similarly, lymph node cells from MSV immune mice or rats did not kill S+L- cells, although they were cytotoxic against target cells known to carry MuLV-associated antigens. Thus, the present study gives no positive evidence for the existence of any MSV-induced new surface antigen in the transformed target cell, known to carry the viral genome

    Formal Verification of the LDACS MAKE Protocol

    Get PDF
    In our talk, we present the first formal verification of the security properties of the updated LDACS 3-pass Mutual Authentication and Key Establishment (MAKE) protocol. This protocol allows AS and GS to establish shared keys via Diffie-Hellman or a Key Encapsulation Mechanism, and to mutually authenticate communication partners in a three-way handshake. There are two variants: (1) The LDACS IKEv2 based 3-pass MAKE protocol and (2) the LDACS ISO/IEC 11770-3:2021 key agreement mechanism 7 based 3-pass MAKE protocol. The verification is done with the Tamarin Prover. We present our approach, point out security features and highlight difficulties in modelling the protocol correctly. Our work supports the on-going design and standardization process of LDACS
    corecore