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A nonlinear relapse model with disaggregated contact rates:Analysis of a forward-backward bifurcation

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Infectious Disease Modelling 2023年第3期8卷 769-782页

作者： Jimmy Calvo-Monge Fabio Sanchez Juan Gabriel Calvo Dario Mena Escuela de Matematica Universidad de Costa RicaCiudad Universitaria Rodrigo FacioSan Jose11501Costa Rica centro de investigacion en Matematica Pura y aplicada Universidad de Costa RicaCiudad Universitaria Rodrigo FacioSan Jose11501Costa Rica

Throughout the progress of epidemic scenarios,individuals in different health classes are expected to have different average daily contact behavior.This contact heterogeneity has been studied in recent adaptive models and allows us to capture the inherent differences across health statuses better.Diseases with reinfection bring out more complex scenarios and offer an important application to consider contact disaggregation.Therefore,we developed a nonlinear differential equation model to explore the dynamics of relapse phenomena and contact differences across health statuses.Our incidence rate function is formulated,taking inspiration from recent adaptive algorithms.It incorporates contact behavior for individuals in each health class.We use constant contact rates at each health status for our analytical results and prove conditions for different forward-backward bifurcation scenarios.The relationship between the different contact rates heavily in-fluences these conditions.numerical examples highlight the effect of temporarily recov-ered individuals and initial conditions on infected population persistence.

关键词： nonlinear relapse nonlinear incidence MaMthematical model Backward bifurcation Adaptive behavior 2000 MSC 37n25 92B05

nano to micro size transition of hydroxyapatite in porcine bone during heat treatment with low heating rates

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Progress in natural Science:Materials International 2020年第4期30卷 494-501页

作者： Angélica M.Castillo-Paz Sandra M.Londo?o-Restrepo Liliana Tirado-Mejía M.A.Mondragón Mario E.Rodríguez-García Grupo de Optoelectrónica Instituto Interdisciplinario de las Ciencias Universidad del Quindío centro de investigación y de Estudios Avanzados del IPn departamento de nanotecnología Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma de México Campus Juriquilla

This work focuses on the changes of raw hydroxyapatite obtained from porcine bones during heat treatment with heating rates of 2.5 and 5.0 °C/min between 600 °C and 1100 °C. High-Resolution transmission electron microscopy(HR-TEM) images showed that raw hydroxyapatite was formed by high-ordered nanometric platelet crystals with a length of around 18 nm and width around 7 nm. High-Resolution scanning electron microscopy(HR-SEM) images evidenced the coalescence phenomena during heating giving. It was found that the growth of the crystals and the transition from nano to a micro-size occurred at around 700 °C. And the changes in the full width at half maximum(FWHM) for the characteristic(002) plane of the X-ray diffraction patterns and the FWHM of the characteristic Raman band at 960 cm-1 for ν1 PO43-exhibited the transition from nano to a micro size, that was confirmed by HR-SEM images and the thermogravimetric(TG) analysis. The porosity of the BIOHAp changes from intra nanometric to intercrystalline.

关键词： Bone composition Hydroxyapatite nanoparticles Mineral composition Porosity formation Raman analysis

Forage offering and seasonal intake comparisons to evaluate European rabbit threat in nothofagus forests of southern Patagonia

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Ecological Processes 2022年第1期11卷 604-617页

作者： Alejandro Huertas Herrera Mónica Toro‑Manríquez Laura Borrelli María Vanessa Lencinas Guillermo Martínez Pastur centro de investigación en Ecosistemas de la Patagonia(CIEP) Camino Baguales s/n Km 4CoyhaiqueChile Ulterarius Consultores Ambientales y Científicos Ltda. Ignacio Serrano 420CoyhaiqueChile Instituto nacional de tecnología Agropecuaria(InTA) EEA BarilocheModesta Victoria 44508400 San Carlos de BarilocheRío NegroArgentina Laboratorio de Recursos Agroforestales Centro Austral de Investigaciones Científicas(CADIC)Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)Houssay 2009410 UshuaiaTierra del FuegoArgentina.

Background:The European rabbit(Oryctolagus cuniculus L.1758)was introduced into different regions of the world,generating significant trade‑offs that critically impacted native vegetation.Here,we evaluate the rabbit’s forage intakes in three vegetation types(forests,shrublands,and grasslands)along the four seasons in a temperate forest landscape in Southern Patagonia and discuss the potential threats over native vegetation.We formulated the following questions:(i)what is the forage offer at each vegetation type?(ii)what is the rabbit’s forage intake and how it varied across the seasons along the year?and(iii)which vegetation types and plant life forms were more used according to the rabbit’s forage intakes?Methods:We censused understory vegetation to characterize the forage offer at each vegetation type and determined seasonal dietary intakes using microhistological analysis of pellets.The plant species identified in the field were grouped according to life form classes(tree regeneration,shrubs,forbs,graminoids,orchids,ferns,bryophytes,and hemiparasites).Data were analysed through uni‑and multi‑variate analyses,determining relationships between forage offer and the rabbit’s forage intakes.Results:Forage intakes revealed changes in plant life form consumption across vegetation types,where intake pressure was considerably different for tree regeneration(p=0.001),graminoids(p=0.001),and hemiparasites(p=0.001).Besides,significant changes in consumption among seasons were detected for shrubs(p=0.001),ferns(p=0.030),and hemiparasites(p=0.002).Although many species play an important role in the rabbit’s forage intake networks(e.g.,Chiliotrichum diffusum,Holcus lanatus),the strongest intake linkages were found in exotic grasses(e.g.,Poa pratensis and Festuca sp.),native hemiparasites(e.g.,Misodendrum sp.),native shrubs(e.g.,Empetrum rubrum),and native trees(e.g.,nothofagus sp.).The summer and autumn seasons presented higher intake compared to the winter and spring seasons.Furthermore,hemiparasites intake(e.g.,Misodendrum

关键词： Forest ecology Oryctolagus cuniculus Plant-animal interaction Vegetation type Herbivory Habitat use

Proline and Oxidative Metabolism in young Pecan Trees Associated with Sulphate Accumulation

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Phyton-International Journal of Experimental Botany 2022年第6期91卷 1141-1152页

作者： Dalila Jacqueline Escudero-Almanza Oscar Cruz-Alvarez Ofelia Adriana Hernández-Rodríguez Juan Luis Jacobo-Cuellar Esteban Sánchez-Chávez Pablo Preciado-Rángel Dámaris Leopoldina Ojeda-Barrios Facultad de ciencias Agrotecnológicas Universidad Autónoma de ChihuahuaChihuahua31350México centro de investigación en Alimentación y desarrollo A.C.Delicias33088México Institutotecnologico nacional de México-Instituto Tecnológico de Torreón Coahuila27170México

Pecan[Carya illinoinensis(Wangenh.)K.Koch.]is a deciduous tree whose fruits(nuts)are of high economic value and offer excellent nutritional benefits.However,soils high in sulphates can limit its growth and development.Working with 5-year-old trees of‘Western Schley’pecan grown in soils high in sulphates,the levels of proline and oxidative metabolism were recorded in the leaflets.Results showed that different levels of visible leaflet damage(‘sufficiency’,‘low’,‘moderate’or‘severe’)were associated with different levels of leaflet sulphates(mg kg^(−1)):‘sufficiency’(≤40),‘low’(41–60),‘moderate’(61–80)and‘severe’(80–100).‘Severe’sulphate damage was associated with significant reductions in chlorophyll(TChl)(17.04μg g^(−1)),relative water content(RWC)(50%)and leaf area(LA),and with increases in the concentrations of total carotenoids(TC)and proline(Prl).Increases were also observed in the activities of the oxidative metabolism enzymes:superoxide dismutase(SOD)(1.82 units min^(−1) g^(−1)),catalase(CAT)(2.86μmol H_(2)O_(2) min^(−1) g^(−1))and antioxidant capacity(AC)(87%DPPH inhibition).However,guaiacol peroxidase(GP)showed a reduction(2.97 nmol GSH min^(−1) g^(−1)).An inverse relationship was found between the sulphate concentration in the leaflets with respect to the evaluated parameters of TChl,TC,RWC,LA,AC,and GP.Proline synthesis and antioxidant enzymatic activity indicate salt stress in pecan leaflets in orchards irrigated with deep-well water high in sulphates.

关键词： Carya illinoinensis catalase guaiacol peroxidase salt stress photosynthetic pigments superoxide dismutase

Unraveling the morphological patterns of a subantarctic eelpout:a geometric morphometric approach

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Integrative Zoology 2023年第2期18卷 372-384页

作者： Fernanda S.ORREGO Mathias HÜnE Hugo A.BenÍTEZ Mauricio F.LAnDAETA Laboratorio de Ictiología e Interacciones Biofísicas(LABITI) Instituto de BiologíaFacultad de CienciasUniversidad de ValparaísoValparaísoChile centro de investigación para la Conservación de los Ecosistemas Australes(ICEA) Punta ArenasChile Laboratorio de Ecología y Morfometría Evolutiva Centro de Investigación de Estudios Avanzados del MauleUniversidad Católica del MauleTalcaChile centro de Observación Marino para Estudios de Riesgos del Ambiente Costero(COSTA-R) Universidad de ValparaísoViña del MarChile Millennium nucleus for Ecology and Conservation of Temperate Mesophotic Reef Ecosystems(nUTME) Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems(BASE) SantiagoChile

Phenotypic variation in organisms depends on the genotype and the environmental constraints of the habitat that they exploit.Therefore,for marine species inhabiting contrasting aquatic conditions,it is expected toﬁnd covari-ation between the shape and its spatial distribution.We studied the morphology of the head and cephalic sensory canals of the eelpout Austrolycus depressiceps(4.5–22.5 cm TL)across its latitudinal distribution in South Paciﬁc(45°S–55°S).Geometric morphometric analyses show that the shape varied from individuals with larger snout and an extended suborbital canal to individuals with shorter snouts and frontally compressed suborbital canal.There was size variation across the sampled populations,but that size does not have a clear latitudinal gradient.Only 8%of the shape variation relates to this size variation(allometry),represented by a decrease in the relative size of the eye,and a depression of the posterior margin of the head.There were spatial differences in the shape of the head,but these differences were probably caused by allometric effects.Additionally,2 of the canals of the cephalic lateralis pores and the head shape showed modularity in its development.This study shows that the morphology of marineﬁsh with a shallow distribution varies across distances of hundreds of kilometers(i.e.,phenotypic modulation).

关键词： Austrolycus depressiceps geometric morphometrics morphology phenotype spatial distribution

3D printing of ABS nanocomposites.Comparison of processing and effects of multi-wall and single-wall carbon nanotubes on thermal,mechanical and electrical properties

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Journal of Materials Science & Technology 2022年第26期121卷 52-66页

作者： Sithiprumnea Dul Brenda J.Alonso Gutierrez Alessandro Pegoretti Jaime Alvarez-Quintana Luca Fambri department of Industrial engineering and InSTM Research Unit University of TrentoTrento 38123Italy centro de investigación en Materiales Avanzados S.C.Unidad MonterreyApodaca 66600Mexico Facultad de Ingeniería Mecánica y Eléctrica Universidad Autónoma de Nuevo LeónAvenida Universidad s/nCiudad UniversitariaSan Nicolás de los Garza 66451México

The following paper reports on a comparative study of the effects of two types of carbon nanotubes,namely multiwall(MWCnT)and single-wall(SWCnT)carbon nanotube,on the properties of 3D-printed parts produced with acrylonitrile-butadiene-styrene(ABS)nanocomposites with various CnT loadings of5-10 wt.%.Quasi-static tensile properties and Vicat softening temperature of 3D-printed parts were enhanced with the increasing CnT content.The highest enhancement in tensile properties was observed for the ABS/CnT nanocomposites at 10 wt.%filler loading.3D-printed ABS/SWCnT composites showed higher tensile modulus,better creep stability and higher Vicat temperature.However,the strength of ABS/SWCnT 3D samples is relatively lower than that of ABS/MWCnT.In addition,3D-printed parts exhibited anisotropic electrical conductive behaviour,which has a conductivity of through-layer of about2-3 orders of magnitude higher than cross-layer.The highest conductivity of 3D-printed samples reached25.2 S/m,and 9.3 S/m for ABS/MWCnT and ABS/SWCnT composites at 10 wt.%,respectively.The results obtained,i.***.the successful fuse filament fabrication and the consequent electromechanical properties,confirm that these 3D printable nanocomposite could be properly utilized for the production,and application up to about 90°C,of thermoelectric devices and/or resistors for flexible circuits.

关键词： Fuse filament fabrication Conductive polymers nanocomposites Mechanical properties Creep behavior Resistivity

Preparation and Characterization of Flexible, Transparent and Thermally Stable Aromatic Co-polyamides

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Chinese Journal of Polymer Science 2019年第2期37卷 136-141页

作者： José Antonio Tec-Sánchez Andrés Iván Oliva Arias Manuel Aguilar-Vega Juan Valerio Cauich-Rodríguez José Luis Santiago-García Unidad de Materiales Centro de Investigación Científica de Yucatán A. C. centro de investigación y de Estudios Avanzados del IPn Unidad Mérida Departamento de Física Aplicada

Two aromatic co-polyamides were synthesized combining two diacid monomers containing bulky pendant groups, 5-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)isophthalic acid(deAIA) and 5-tert-butylisophthalic acid(TERT), with 4,4′-(hexafluoroisopropylidene)dianiline(HFA) or 2,3,5,6-tetramethyl-1,4-phenylenediamine(Durene) by direct polycondensation. The structures of the obtained aromatic co-polyamides were confirmed by FTIR, Raman and 1 H-nMR. The co-copolyamide films, DHTH and DDTD, exhibited rms-roughness values between 0.94 and 1.60 nm, respectively. Moreover, they presented good thermal stability up to300 °C. young's moduli of the co-polyamide films were between 4.1 and 4.3 GPa. X-ray diffraction results showed that the co-polyamide films were amorphous due to the incorporation of both bulky pendant groups, tert-butyl and dibenzobarrelene. The combination of bulky pendant groups provided intrinsically transparent co-polyamide films with a transmittance higher than 88% in the range of 400-780 nm.Due to these outstanding film and optical properties, they are suggested to be flexible substrates in applications for solar cell and other portable electronic devices.

关键词： Co-polyamides Flexible films Transmittance Thermal stability Polycondensation

non-Linear Effects in Optical Systems by Lie Algebra and Symplectic Mapping

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Journal of Modern Physics 2022年第11期13卷 1314-1323页

作者： Víctor M. Casta&ntilde o centro de Física aplicada y tecnología avanzada/Secretaría de desarrollo Institucional Universidad Nacional Autónoma de México Queretaro México

The use of signals of different frequencies determines the geometrical deviation with respect to the optical axes of a given beam. This angle can be determined by Sympletic Map (SM), a powerful and simple mathematical tool for the characterization and construction of images in Geometrical Optics. The Sympletic Map constitutes a Lie Group, with an algebra associated: the Lie Algebra. In general, the SM can be expressed as an infinite series, where each term corresponds to different contributions produced by the optical devices that constitute the optical system (lenses, apertures, bandwidth cutoff, etc.). The level of correction to be performed on the image to recover the original object is clear and controllable by SM. This formalism can be extended easily to physical optics to describe diffraction and interference phenomena.

关键词： Symplectic Mapping Geometrical Optics non-Linear Effects

Caerulin-induced pancreatitis in rats: Histological and genetic expression changes from acute phase to recuperation

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World Journal of Gastroenterology 2006年第25期12卷 3999-4003页

作者： Javier Magaa-Gómez Guillermo López-Cervantes Ana María Calderón de la Barca departamento de nutrición centro de investigación en Alimentación y desarrollo A.C. HermosilloSonoraMéxicoDepartamento de Patología Hospital Infantil del Estado de SonoraHermosilloSonoraMéxicoDepartamento de Nutrición Centro de Investigación en Alimentación y DesarrolloA.C.HermosilloSonoraMéxico

瞄准：为了学习组织学、联系胰腺炎的蛋白质 mRnA 累积，在老鼠从导致 caerulin 的胰腺炎的尖锐阶段胰改变到恢复。方法：尖锐胰腺炎被 caerulein 在男 Wistar 老鼠导致并且列在后面在上面为 90 d 由组织学并且胰的 mRnA 分析。胰在 0 ... 详细信息

瞄准：为了学习组织学、联系胰腺炎的蛋白质 mRnA 累积，在老鼠从导致 caerulin 的胰腺炎的尖锐阶段胰改变到恢复。方法：尖锐胰腺炎被 caerulein 在男 Wistar 老鼠导致并且列在后面在上面为 90 d 由组织学并且胰的 mRnA 分析。胰在 0 点被把， 9， 24 h 并且 3， 5， 15， 30， 60， 90 d 正式就职以后。浮肿(E) ， polymorphonuclear neutrophil (PMn ) 渗入，细胞质的空泡形成(V) ，酶原小粒弄空(ZD ) 和腺泡组织的破坏(广告) 是评估的用显微镜。联系胰腺炎的蛋白质(奶头) 和 L13A mRnAs 的累积被即时 PCR 确定。结果：主要组织学的变化出现在为 PMn 渗入和细胞质的 V 正式就职以后的 9 h 在为 E 和 ZD 的 24 h 和 3 d 分别地。所有参数在 5 d 以后被恢复，除了推迟了超过 30 d 的 ZD。主要广告在 15 d 以后被观察，值在 30 d 以后回到了正常。同样到组织学的变化， PAP mRnA 的累积在 24 h 与最高的累积在 9 h 被增加，差别消失在 5 d 以后。结论：从尖锐阶段发生到胰的胰腺炎，新生和重新区别的恢复并且奶头表示是只胰腺炎的尖锐回答。

关键词：雨蛙肽胰腺炎组织遗传疾病