Exploring Bicycle and Public Transit Use by Low-Income Latino Immigrants: A Mixed-Methods Study in the San Francisco Bay Area

Latin American immigrants will continue to make up a large share of transit ridership, bicycling and walking in the United States for the foreseeable future, but there is relatively little research about them. This mixed-methods study compares the travel patterns of low-income immigrants living in the San Francisco Bay Area with that of other groups and investigates the barriers and constraints faced by low-income immigrants when taking transit and bicycling. Much of the previous work on immigrant travel has relied on national surveys and qualitative analysis, which underrepresent disadvantaged population groups and slower modes of travel, or are unable to speak to broader patterns in the population. We conducted interviews with 14 low-income immigrants and a paper-based intercept survey of 2,078 adults. Interviewees revealed five major barriers that made public transit use difficult for them, including safety, transit fare affordability, discrimination, system legibility, and reliability. Although crime was the most prominent issue in interviews, the survey results suggest transit cost is the most pressing concern for low-income immigrants. Low-income immigrants were less likely than those with higher-incomes to have access to a motor vehicle, and were less likely than higher-income immigrants or the U.S.-born of any income to have access to a bicycle or bus pass. Finally, although most barriers to public transit use were the same regardless of nativity or household income, low-income immigrants were much less willing to take public transit when they had the option to drive and less willing to bicycle for any purpose. The prevalence of concerns about transit affordability, crime, and reliability suggest transit agencies should consider income-based fare reductions, coordinated crime prevention with local law enforcement, and improved scheduling

Percepción del acento prosódico en vocablos leídos: un estudio con hablantes nativos de coreano en clases universitarias de ELE de nivel avanzado

El artículo analiza los problemas del aprendizaje del componente fónico del español por parte de hablantes coreanos que siguen cursos de nivel avanzado en la Universidad de Hankuk. El estudio se centra específicamente en la percepción de la sílaba tónica en vocablos bisílabos y trisílabos del español. La existencia en coreano de un acento distintivo basado en la cantidad es una cuestión controvertida por lo que es especialmente relevante estudiar las dificultades de los hablantes coreanos en el proceso de aprendizaje del español. Por otra parte, el hecho de que los estudiantes analizados hablan también inglés puede constituir un factor importante que contribuya a facilitar la percepción del acento distintivo del español.The article analyses the problems that Korean  speakers who attend the advanced level Spanish courses at the Hankuk University present when learning the phonic component. The study is specifically focused on the perception of the stressed syllable in Spanish disyllabic and trisyllabic words. The existence in Korean of a distinctive accent based in the amount is a controversial issue, so it is especially relevant to study the Korean speakers’ difficulties during the process of learning Spanish. On the other side, the fact that the analysed students also speak English can constitute an important element that contributes to facilitate the perception of the Spanish distinctive accent.El artículo analiza los problemas del aprendizaje del componente fónico del español por parte de hablantes coreanos que siguen cursos de nivel avanzado en la Universidad de Hankuk. El estudio se centra específicamente en la percepción de la sílaba tónica en vocablos bisílabos y trisílabos del español. La existencia en coreano de un acento distintivo basado en la cantidad es una cuestión controvertida por lo que es especialmente relevante estudiar las dificultades de los hablantes coreanos en el proceso de aprendizaje del español. Por otra parte, el hecho de que los estudiantes analizados hablan también inglés puede constituir un factor importante que contribuya a facilitar la percepción del acento distintivo del español

Ubiquitination of tombusvirus p33 replication protein plays a role in virus replication and binding to the host Vps23p ESCRT protein

AbstractPost-translational modifications of viral replication proteins could be widespread phenomena during the replication of plus-stranded RNA viruses. In this article, we identify two lysines in the tombusvirus p33 replication co-factor involved in ubiquitination and show that the same lysines are also important for the p33 to interact with the host Vps23p ESCRT-I factor. We find that the interaction of p33 with Vps23p is also affected by a “late-domain”-like sequence in p33. The combined mutations of the two lysines and the late-domain-like sequences in p33 reduced replication of a replicon RNA of Tomato bushy stunt virus in yeast model host, in plant protoplasts, and plant leaves, suggesting that p33-Vps23p ESCRT protein interaction affects tombusvirus replication. Using ubiquitin-mimicking p33 chimeras, we demonstrate that high level of p33 ubiquitination is inhibitory for TBSV replication. These findings argue that optimal level of p33 ubiquitination plays a regulatory role during tombusvirus infections

On the module of differentials of order n of hypersurfaces

Se da una presentación del módulo de diferenciales de orden superior en términos de una matriz jacobiana que involucra derivadas de orden superior. Se estudian varias consecuencias de esta presentación en el caso de hipersuperficies.We give an explicit presentation of the module of differentials of or-dernof a finitely generated algebra via a higher-order Jacobian matrix.We use the presentation to study some aspects of this module in thecase of hypersurfaces. More precisely, we prove higher-order versionsof known results relating freness and torsion-freness of the module ofdifferentials with the regularity and normality of the hypersurface. Wealso study its projective dimension

A NOBILE-LIKE THEOREM FOR JET SCHEMES OF HYPERSURFACES

We prove that the blowup of the jet scheme of a singular hypersurface along a certain jetrelated module is not an isomorphism. In conjunction with recent developments in the theory of Nash blowups, our result holds over fields of arbitrary characteristic. Our approach is based on explicit presentations given by a higher-order Jacobian matrix combined with a certain jetrelated matrix

The Proteasomal Rpn11 Metalloprotease Suppresses Tombusvirus RNA Recombination and Promotes Viral Replication via Facilitating Assembly of the Viral Replicase Complex

RNA viruses co-opt a large number of cellular proteins that affect virus replication and, in some cases, viral genetic recombination. RNA recombination helps viruses in an evolutionary arms race with the host\u27s antiviral responses and adaptation of viruses to new hosts. Tombusviruses and a yeast model host are used to identify cellular factors affecting RNA virus replication and RNA recombination. In this study, we have examined the role of the conserved Rpn11p metalloprotease subunit of the proteasome, which couples deubiquitination and degradation of proteasome substrates, in tombusvirus replication and recombination in Saccharomyces cerevisiae and plants. Depletion or mutations of Rpn11p lead to the rapid formation of viral RNA recombinants in combination with reduced levels of viral RNA replication in yeast or in vitro based on cell extracts. Rpn11p interacts with the viral replication proteins and is recruited to the viral replicase complex (VRC). Analysis of the multifunctional Rpn11p has revealed that the primary role of Rpn11p is to act as a matchmaker that brings the viral p92pol replication protein and the DDX3-like Ded1p/RH20 DEAD box helicases into VRCs. Overexpression of Ded1p can complement the defect observed in rpn11 mutant yeast by reducing TBSV recombination. This suggests that Rpn11p can suppress tombusvirus recombination via facilitating the recruitment of the cellular Ded1p helicase, which is a strong suppressor of viral recombination, into VRCs. Overall, this work demonstrates that the co-opted Rpn11p, which is involved in the assembly of the functional proteasome, also functions in the proper assembly of the tombusvirus VRCs. IMPORTANCE: RNA viruses evolve rapidly due to genetic changes based on mutations and RNA recombination. Viral genetic recombination helps viruses in an evolutionary arms race with the host\u27s antiviral responses and facilitates adaptation of viruses to new hosts. Cellular factors affect viral RNA recombination, although the role of the host in virus evolution is still understudied. In this study, we used a plant RNA virus, tombusvirus, to examine the role of a cellular proteasomal protein, called Rpn11, in tombusvirus recombination in a yeast model host, in plants, and in vitro. We found that the cellular Rpn11 is subverted for tombusvirus replication and Rpn11 has a proteasome-independent function in facilitating viral replication. When the Rpn11 level is knocked down or a mutated Rpn11 is expressed, then tombusvirus RNA goes through rapid viral recombination and evolution. Taken together, the results show that the co-opted cellular Rpn11 is a critical host factor for tombusviruses by regulating viral replication and genetic recombination

Precessing models and eventual links with galaxy warps

The Restricted Three Body problem is a basic model in celestial mechanics and it has been extensively used in the design of some spatial missions. Sometimes, the designers of these missions consider other similar models which are perturbations of this because the physical reality is more complex and they have to take into account the influence of other physical phenomena. In this work, the idea of the Restricted Three Body problem is adapted to a precession phenomenon. This precession is considered in different ways and, as a result, different models are obtained. It will be important to analyze the models by computing the invariant objects like critical points, periodic orbits and invariant manifolds. Another objective of this work is to see how a precessing models can be useful when applied to galactic dynamics, which is an important field where the results of celestial mechanics have been widely used. In this case, a precessing model can be a first approximation to explain the warps observed in some galaxies. En aquest projecte s'estudiaran diversos models gravitacionals de sistemes dinàmics en un sistema giratori on els primaris, o un solid rigid, esta subjecte a moviments de precessió. L'objectiu consisteix en fer els models, calcular els equivalents als punts d'equilibri colineals, calcular també objectes invariants i com aplicació veure si es poden explicar els warps que apareixen en galaxies barrades

Novel Mechanism of Regulation of \u3cem\u3eTomato Bushy Stunt Virus\u3c/em\u3e Replication by Cellular WW-Domain Proteins

Replication of (+)RNA viruses depends on several co-opted host proteins but is also under the control of cell-intrinsic restriction factors (CIRFs). By using tombusviruses, small model viruses of plants, we dissect the mechanism of inhibition of viral replication by cellular WW-domain-containing proteins, which act as CIRFs. By using fusion proteins between the WW domain and the p33 replication protein, we show that the WW domain inhibits the ability of p33 to bind to the viral RNA and to other p33 and p92 replication proteins leading to inhibition of viral replication in yeast and in a cell extract. Overexpression of WW-domain protein in yeast also leads to reduction of several co-opted host factors in the viral replicase complex (VRC). These host proteins, such as eEF1A, Cdc34 E2 ubiquitin-conjugating enzyme, and ESCRT proteins (Bro1p and Vps4p), are known to be involved in VRC assembly. Simultaneous coexpression of proviral cellular factors with WW-domain protein partly neutralizes the inhibitory effect of the WW-domain protein. We propose that cellular WW-domain proteins act as CIRFs and also as regulators of tombusvirus replication by inhibiting the assembly of new membrane-bound VRCs at the late stage of infection. We suggest that tombusviruses could sense the status of the infected cells via the availability of cellular susceptibility factors versus WW-domain proteins for binding to p33 replication protein that ultimately controls the formation of new VRCs. This regulatory mechanism might explain how tombusviruses could adjust the efficiency of RNA replication to the limiting resources of the host cells during infections. IMPORTANCE: Replication of positive-stranded RNA viruses, which are major pathogens of plants, animals, and humans, is inhibited by several cell-intrinsic restriction factors (CIRFs) in infected cells. We define here the inhibitory roles of the cellular Rsp5 ubiquitin ligase and its WW domain in plant-infecting tombusvirus replication in yeast cells and in vitro using purified components. The WW domain of Rsp5 binds to the viral RNA-binding sites of p33 and p92 replication proteins and blocks the ability of these viral proteins to use the viral RNA for replication. The WW domain also interferes with the interaction (oligomerization) of p33 and p92 that is needed for the assembly of the viral replicase. Moreover, WW domain also inhibits the subversion of several cellular proteins into the viral replicase, which otherwise play proviral roles in replication. Altogether, Rsp5 is a CIRF against a tombusvirus, and it possibly has a regulatory function during viral replication in infected cells

Inactivation of the Host Lipin Gene Accelerates RNA Virus Replication through Viral Exploitation of the Expanded Endoplasmic Reticulum Membrane

RNA viruses take advantage of cellular resources, such as membranes and lipids, to assemble viral replicase complexes (VRCs) that drive viral replication. The host lipins (phosphatidate phosphatases) are particularly interesting because these proteins play key roles in cellular decisions about membrane biogenesis versus lipid storage. Therefore, we examined the relationship between host lipins and tombusviruses, based on yeast model host. We show that deletion of PAH1 (phosphatidic acid phosphohydrolase), which is the single yeast homolog of the lipin gene family of phosphatidate phosphatases, whose inactivation is responsible for proliferation and expansion of the endoplasmic reticulum (ER) membrane, facilitates robust RNA virus replication in yeast. We document increased tombusvirus replicase activity in pah1Δ yeast due to the efficient assembly of VRCs. We show that the ER membranes generated in pah1Δ yeast is efficiently subverted by this RNA virus, thus emphasizing the connection between host lipins and RNA viruses. Thus, instead of utilizing the peroxisomal membranes as observed in wt yeast and plants, TBSV readily switches to the vastly expanded ER membranes in lipin-deficient cells to build VRCs and support increased level of viral replication. Over-expression of the Arabidopsis Pah2p in Nicotiana benthamiana decreased tombusvirus accumulation, validating that our findings are also relevant in a plant host. Over-expression of AtPah2p also inhibited the ER-based replication of another plant RNA virus, suggesting that the role of lipins in RNA virus replication might include several more eukaryotic viruses