Structural aspects of tilings

In this paper, we study the structure of the set of tilings produced by any given tile-set. For better understanding this structure, we address the set of finite patterns that each tiling contains. This set of patterns can be analyzed in two different contexts: the first one is combinatorial and the other topological. These two approaches have independent merits and, once combined, provide somehow surprising results. The particular case where the set of produced tilings is countable is deeply investigated while we prove that the uncountable case may have a completely different structure. We introduce a pattern preorder and also make use of Cantor-Bendixson rank. Our first main result is that a tile-set that produces only periodic tilings produces only a finite number of them. Our second main result exhibits a tiling with exactly one vector of periodicity in the countable case.Comment: 11 page

Aplicación de procedimientos según la Metodología SBC para reducir accidentes e incidentes en una empresa de productos hidrobiológicos Sechura 2022

La presente investigación tiene como objetivo principal determinar cuál es la influencia de la aplicación de procedimientos según la metodología SBC para reducir accidentes e incidentes en una empresa hidrobiológica. Para ello se dio a conocer las bases teóricas y conceptuales de esta metodología, la cual está orientada a identificar aquellos comportamientos de riesgo en los trabajadores y cambiarlos por comportamientos seguros buscando contribuir en la reducción de accidentes e incidentes. La investigación fue de tipo aplicada y diseño pre experimental con una muestra de 33 personas, se utilizaron técnicas de recolección de datos como la revisión documental y la observación directa además de la aplicación de instrumentos como la matriz de categorización de accidentes e incidentes y la cartilla de observación directa, información que posteriormente fue ingresada al software SPSS para determinar si se aceptan o rechazan las hipótesis. La aplicación de la metodología SBC permitió reducir el número de accidentes e incidentes los cuales fueron caracterizados al realizar un pre y post test de los datos estadísticos donde se pudo obtener la contrastación de los resultados los cuales mostraron una mejoría en la reducción de accidentes e incidentes como también de las conductas de riesgo

Experiencias de gestión de riesgos en Lima: actores y territorios urbanos

La gestión de riesgos en Lima se hace a través de acciones puntuales, tanto espacial como sectorialmente. Esto se explica en parte por la ausencia de gestión metropolitana de la ciudad y por la fragmentación de las políticas públicas. Por ende, las acciones de gestión de riesgos se hacen esencialmente en función de movilizaciones locales, de conflictos puntuales o de apoyos de instituciones exteriores. Este artículo propone analizar una serie de acciones realizadas según las oportunidades de financiamiento o de movilización de los actores locales. Propone un panorama no exhaustivo de experiencias de gestión de riesgos en Lima y busca identificar actores, territorios y mecanismos puestos en práctica. De este modo, nos ofrece elementos de reflexión sobre las modalidades de gestión de riesgos y sobre los desafíos de la implementación de una política de gestión del riesgo a escala de la aglomeración urbana de Lima/Callao.La gestion des risques à Lima se fait au travers d’actions ponctuelles, spatialement et sectoriellement. Cela s’explique en partie par l’absence de gestion métropolitaine de la ville et du fait de la fragmentation des politiques publiques. Les actions de gestion des risques se font donc essentiellement en fonction de mobilisations locales, de conflits ponctuels ou d’appuis d’institutions extérieures. Cet article propose d’analyser une série d’actions réalisées au gré des opportunités de financement ou de la mobilisation des acteurs locaux. Il propose un panorama non exhaustif d’expériences de gestion des risques à Lima et cherche à identifier les acteurs, les territoires et les mécanismes à l’œuvre. Il apporte ainsi des éléments de réflexion sur les modalités de gestion des risques et sur les enjeux de la mise en place d’une politique de gestion du risque à l’échelle de l’agglomération urbaine de Lima/Callao.Risk management in Lima is made through specific actions, spatially and by sectors. This situation is partially explained by the absence of metropolitan management, as well as public policy fragmentation. Risk management actions essentially are based on local mobilizations, specific conflicts, or support from outside institutions. This article suggests analyzing a series of actions implemented according to financing opportunities or the mobilization of local actors. It proposes a non-exhaustive panorama of risk management experiences in Lima and tries to identify the actors, the territories, and the mechanisms employed. Thus it provides elements for reflection on risk management modalities and on the stakes involved in the implementation of a risk management policy in an urban agglomeration on the scale of Lima/Callao

Planeamiento estratégico del mango en el Perú

El mango del Perú ha registrado en los últimos años una dinámica de crecimiento en las exportaciones del 15.8% en promedio anual, entre 2002 y 2013. Los factores que han influenciado a esta dinámica positiva son: (a) la preocupación cada vez mayor por una alimentación saludable, (c) el posicionamiento del mango peruano como un producto que cumple los estándares de calidad internacional, y (c) la firma de tratados de libre comercio, promoviendo así la llegada a importantes mercados foráneos. Entre los años 2011 y el 2013 el Perú se ha ubicado entre el cuarto y sexto lugar como exportador de mango en el mundo. Los principales destinos del mango peruano son Países Bajos y Estados Unidos. En estos mercados se tiene como principales competidores a México y Brasil. Estos países cuentan con ventajas como extensiones de áreas de cultivo, cercanía a los países destino y permanente desarrollo industrial y comercial del sector. A pesar de esto el Perú en los últimos años ha logrado posicionar destacadamente este fruto tropical y se encuentra incursionando en nuevos mercados. El principal problema del sector es la presencia de varios intermediarios tanto a nivel local principalmente como de exportación. Esta situación y la débil capacidad de gestión empresarial del agricultor peruano generan un reducido nivel de rentabilidad y capacidad para insertarse en la dinámica creciente de exportación. En este sentido, el resultado del plan estratégico es incorporar al agricultor en la cadena de valor de la mediana y gran empresa exportadora a través de: (a) la implementación de buenas prácticas agrícolas, (b) la generación de sinergias entre agricultores que contribuya a fortalecer su capacidad de respuesta comercial, y (c) establecimiento de una asociación que potencie el desarrollo del sectorThe Peruvian mango has registered in recent years a dynamic growth in exports 15.8% in annual average between 2002 and 2013. The factors that have influenced this positive trend are: (a) the growing concern about healthy nutrition, (b) the positioning of Peruvian mango as a product that meets the international quality standards, and (c) the signing of free trade agreements, have promoted arrival in important foreign markets. Between 2011 and 2013, Peru was ranked between the fourth and sixth mango exporter in the world. The main markets for Peruvian mango export are Netherlands and the United States. In these markets the main competitors are Mexico and Brazil. These countries have advantages as extensions of cultivated areas, proximity to destination countries and permanent industrial and commercial development of the sector. Despite this Peru in recent years has positioned outstandingly this tropical fruit and is entering into new markets. The main problem of the sector is the presence of several middlemen for both the local market mainly and for foreign. This situation and the weak business management skills of Peruvian farmer generate a reduced profitability and capacity to insert into the growing export dynamics. Because of this, the result of the strategic plan is to incorporate the farmer in the value chain of medium and large exporting company through: (a) the implementation of best practices in agriculture, (b) generating synergies between farmers to help strengthen their commercial response capacity, and (c) establishment of an association that enhances the development of the sector.Tesi

A high-affinity calmodulin-binding site in the CyaA toxin translocation domain is essential for invasion of eukaryotic cells

The molecular mechanisms and forces involved in the translocation of bacterial toxins into host cells are still a matter of intense research. The adenylate cyclase (CyaA) toxin from Bordetella pertussis displays a unique intoxication pathway in which its catalytic domain is directly translocated across target cell membranes. The CyaA translocation region contains a segment, P454 (residues 454-484), which exhibits membrane-active properties related to antimicrobial peptides. Herein, the results show that this peptide is able to translocate across membranes and to interact with calmodulin (CaM). Structural and biophysical analyses reveal the key residues of P454 involved in membrane destabilization and calmodulin binding. Mutational analysis demonstrates that these residues play a crucial role in CyaA translocation into target cells. In addition, calmidazolium, a calmodulin inhibitor, efficiently blocks CyaA internalization. It is proposed that after CyaA binding to target cells, the P454 segment destabilizes the plasma membrane, translocates across the lipid bilayer and binds calmodulin. Trapping of CyaA by the CaM:P454 interaction in the cytosol may assist the entry of the N-terminal catalytic domain by converting the stochastic motion of the polypeptide chain through the membrane into an efficient vectorial chain translocation into host cells

Elaboration of a Purple Corn Drink with Maximum Retention of Anthocyanins

In the present work, the anthocyanin extraction process was characterized during the elaboration of a purple corn drink, using the response surface analysis method with temperature intervals between 47.57 and 132.43°C, and times from 11, 36 at 138.64 minutes. In addition, with the stationary point technique, the maximum retention of anthocyanin (33.99 mg/g) was determined at a temperature of 98.39°C at a time of 105.89 minutes of extraction. Since this time is too long and to reduce production costs, without resorting to considerable losses of anthocyanins, canonical analysis was used, redefining the optimal extraction parameters at a temperature of 100°C for 60 minutes with a reduction of the anthocyanin content of 2.49% (33.14 mg/g) concerning the maximum, a value that is within the optimum area of performance of the process. With the extract obtained under optimal conditions, a drink was prepared and, using the differential pH method and Student’s t-test (p = 0.05), its anthocyanin content was quantified and compared with that of a commercial drink with typical characteristics. Similar, observing that the elaborated drink presents higher contents, whose difference varies within the range of 2.79 and 4.72 mg/mL. Finally, using a satisfaction test with a nine-point hedonic scale, it was determined that the beverage was “very well liked” by a semi-trained sensory panel

FoxP3+ CD8 T-cells in acute HIV infection and following early antiretroviral therapy initiation

ObjectivesBesides CD4 regulatory T-cells (Tregs), immunosuppressor FoxP3+ CD8 T-cells are emerging as an important subset of Tregs, which contribute to immune dysfunction and disease progression in HIV infection. However, FoxP3+ CD8 T-cell dynamics in acute HIV infection and following early antiretroviral therapy (ART) initiation remain understudied.MethodsSubsets of FoxP3+ CD8 T-cells were characterized both prospectively and cross-sectionally in PBMCs from untreated acute (n=26) and chronic (n=10) HIV-infected individuals, early ART-treated in acute infection (n=10, median of ART initiation: 5.5 months post-infection), ART-treated in chronic infection (n=10), elite controllers (n=18), and HIV-uninfected controls (n=21).ResultsAcute and chronic infection were associated with increased total, effector memory, and terminally differentiated FoxP3+ CD8 T-cells, while early ART normalized only the frequencies of total FoxP3+ CD8 T-cells. We observed an increase in FoxP3+ CD8 T-cell immune activation (HLADR+/CD38+), senescence (CD57+/CD28-), and PD-1 expression during acute and chronic infection, which were not normalized by early ART. FoxP3+ CD8 T-cells in untreated participants expressed higher levels of immunosuppressive LAP(TGF-β1) and CD39 than uninfected controls, whereas early ART did not affect their expression. The expression of gut-homing markers CCR9 and Integrin-β7 by total FoxP3+ CD8 T-cells and CD39+ and LAP(TGF-β1)+ FoxP3+ CD8 T-cells increased in untreated individuals and remained higher than in uninfected controls despite early ART. Elite controllers share most of the FoxP3+ CD8 T-cell characteristics in uninfected individuals.ConclusionsAlthough early ART normalized total FoxP3+ CD8 T-cells frequencies, it did not affect the persistent elevation of the gut-homing potential of CD39+ and LAP(TGF-β1)+ FoxP3+ CD8 T-cell, which may contribute to immune dysfunction

Evaluation of treatment response in adults with relapsing MOG-Ab-associated disease

Background: Myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) are related to several acquired demyelinating syndromes in adults, but the therapeutic approach is currently unclear. We aimed to describe the response to different therapeutic strategies in adult patients with relapsing MOG-Ab-associated disease. Methods: This is a retrospective study conducted in France and Spain including 125 relapsing MOG-Ab patients aged ≥ 18 years. First, we performed a survival analysis to investigate the relapse risk between treated and non-treated patients, performing a propensity score method based on the inverse probability of treatment weighting. Second, we assessed the annualised relapse rates (ARR), Expanded Disability Status Scale (EDSS) and visual acuity pre-treatment and on/end-treatment. Results: Median age at onset was 34.1 years (range 18.0-67.1), the female to male ratio was 1.2:1, and 96% were Caucasian. At 5 years, 84% (95% confidence interval [CI], 77.1-89.8) patients relapsed. At the last follow-up, 66 (52.8%) received maintenance therapy. Patients initiating immunosuppressants (azathioprine, mycophenolate mophetil [MMF], rituximab) were at lower risk of new relapse in comparison to non-treated patients (HR, 0.41; 95CI%, 0.20-0.82; p = 0.011). Mean ARR (standard deviation) was reduced from 1.05(1.20) to 0.43(0.79) with azathioprine (n = 11; p = 0.041), from 1.20(1.11) to 0.23(0.60) with MMF (n = 11; p = 0.033), and from 1.08(0.98) to 0.43(0.89) with rituximab (n = 26; p = 0.012). Other immunosuppressants (methotrexate/mitoxantrone/cyclophosphamide; n = 5), or multiple sclerosis disease-modifying drugs (MS-DMD; n = 9), were not associated with significantly reduced ARR. Higher rates of freedom of EDSS progression were observed with azathioprine, MMF or rituximab. Conclusion: In adults with relapsing MOG-Ab-associated disease, immunosuppressant therapy (azathioprine, MMF and rituximab) is associated with reduced risk of relapse and better disability outcomes. Such an effect was not found in the few patients treated with MS-DMD

Design and Characterization of an Electrically Powered Single Molecule on Gold

The surface diffusion of individual molecules is of paramount importance in self-assembly processes and catalytic processes. However, the fundamental understanding of molecule diffusion peculiarities considering conformations and adsorption sites remain poorly known at the atomic scale. Here, we probe the 4′-(4-tolyl)-2,2′:6′,2″-terpyridine adsorbed on the Au(111) herringbone structure combining scanning tunneling microscopy and atomic force microscopy. Molecules are controllably translated by electrons excitations over the reconstruction, except at elbows acting as pinning centers. Experimental data supported by theoretical calculations show the formation of coordination bonds between the molecule and Au atoms of the surface. Using force spectroscopy, we quantify local variation of the surface potential and the lateral force required to move the molecule. We found an elevation of the diffusion barrier at elbows of the reconstruction of ∼100 meV compared to the rest of the surface

Pre-existing immunity to SARS-CoV-2 before the COVID-19 pandemic era in Cameroon: A comparative analysis according to HIV-status

BackgroundThe lower burden of COVID-19 in tropical settings may be due to preexisting cross-immunity, which might vary according to geographical locations and potential exposure to other pathogens. We sought to assess the overall prevalence of SARS-CoV-2 antibodies and determine SARS-CoV-2 seropositivity according to HIV-status before the COVID-19 pandemic era. MethodsA cross-sectional and comparative study was conducted at the Chantal BIYA International Reference Centre (CIRCB) on 288 stored plasma samples (163 HIV-positive versus 125 HIV-negative); all collected in 2017-2018, before the COVID-19 pandemic era. Abbott Panbio (TM) COVID-19 IgG/IgM assay was used for detecting SARS-CoV-2 immunoglobulin G (IgG) and M (IgM). Among people living with HIV (PLHIV), HIV-1 viral load and TCD4 cell count (LTCD4) were measured using Abbott Real Time PCR and BD FACSCalibur respectively. Statistical analyses were performed, with pResultsThe median [IQR] age was 25 [15-38] years. Overall seropositivity to SARS-CoV-2 antibodies was 13.5% (39/288) of which 7.3% (21) was IgG, 7.3% (21) IgM and 1.0% (3) IgG/IgM. According to HIV-status in the study population, SARS-CoV-2 seropositivity was 11.0% (18/163) among HIV-positive versus 16.8% (21/125) among HIV-negative respectively, p=0.21. Specifically, IgG was 6.1% (10/163) versus 8.8% (11/125), p=0.26; IgM was 5.5% (9/163) versus 9.6%, (12/125), p=0.13 and IgG/IgM was 0.6% (1/163) versus 1.6% (2/125) respectively. Among PLHIV, SARS-CoV-2 seropositivity according to CD4 count was 9.2% (>= 500 cells/mu L) versus 1.8% (200-499 cells/mu L), (OR=3.5; p=0.04) and 0.6% (<200 cells/mu L), (OR=17.7; p<0.01). According to viral load, SARS-CoV-2 seropositivity was 6.7% (>= 40 copies/mL) versus 4.9% (<40 copies/mL), (OR= 3.8; p<0.01). ConclusionBefore COVID-19 in Cameroon, cross-reactive antibodies to SARS-CoV-2 were in circulation, indicating COVID-19 preexisting immunity. This preexisting immunity may contribute in attenuating disease severity in tropical settings like Cameroon. Of relevance, COVID-19 preexisting immunity is lower with HIV-infection, specifically with viral replication and poor CD4-cell count. As poor CD4-count leads to lower cross-reactive antibodies (regardless of viral load), people living with HIV appear more vulnerable to COVID-19 and should be prioritized for vaccination