检索结果-南通市图书馆

Freeze-thaw cycles and associated geomorphology in a post-glacial environment:current glacial,paraglacial,periglacial and proglacial scenarios at Pico de Orizaba volcano,Mexico

引用

Journal of Mountain Science 2024年第6期21卷 1954-1977页

作者： Víctor SOTO Carlos M.WELSH R. Kenji YOSHIKAWA hugo delgado granados Centro de Ciencias de la Tierra Universidad VeracruzanaCircuito Gonzalo Aguirre BeltránS/NZona Universitaria91090XalapaMéxico Water and Environmental Research Center University of Alaska FairbanksFairbanksAlaska 99775USA Instituto de Geofísica Universidad Nacional Autónoma de MéxicoCiudad de México 04150México Department of Earth and Environmental Sciences Ludwig Maximilians UniversitätMunich 80333Germany

The glacial history of Pico de Orizaba indicates that during the Last Glacial Maximum,its icecap covered up to~3000 m asl;due to the air temperature increasing,its main glacier has retreated to 5050 m *** retraction of the glacier has left behind an intense climatic instability that causes a high frequency of freeze-thaw cycles of great intensity;the resulting geomorphological processes are represented by the fragmentation of the bedrock that occupies the upper parts of the *** is a notable lack of studies regarding the fragmentation and erosion occurring in tropical high mountains,and the associated geomorphological risks;for this reason,as a first stage of future continuous research,this study analyzes the freezing and thawing cycles that occur above 4000 m asl,through continuous monitoring of surface ground *** results allow us to identify and characterize four zones:glacial,paraglacial,periglacial and *** was found that the paraglacial zone presents an intense drop of temperature,of up to~9℃ in only sixty *** rock fatigue and intense freeze-thaw cycles that occur in this area are responsible for the high rate of rock disintegration and represent the main factor of the constant slope dynamics that occur at the *** activity decreases,both in frequency and intensity,according to the distance to the glacier,which is where the temperature presents a certain degree of stability,until reaching the proglacial zone,where cycles are almost non-existent,and therefore there is no gelifraction *** geomorphological processes have resulted in significant alterations to the mountain slopes,which can have severe consequences in terms of risk and water.

关键词： Freeze-Thaw Gelifraction Mountain mechanical erosion Periglacial geomorphology Postglacial scenarios

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Glacial reconstruction and periglacial dynamics at the end of Late Pleistocene on the surface of Cofre de Perote volcano,México:a climatological retrospective

引用

Journal of Mountain Science 2023年第9期20卷 2453-2467页

作者： Victor SOTO hugo delgado-granados Carlos M.WELSH Kenji YOSHIKAWA Centro de Ciencias de la Tierra Universidad VeracruzanaXalapaVeracruz 91090México Instituto de Geofísica Universidad Nacional Autónoma de MéxicoCiudad de México 04150México Water and Environmental Research Center University of Alaska FairbanksFairbanksAlaska 99775USA

Despite being within the intertropical region of the planet,the Mexican territory still has glacier-covered *** recent decades,important advances have been made in studies on glaciology and periglacial environment in Mexico both for current and past ***,in spite of Cofre de Perote volcano(4200 m a.s.l.)being a strategically located mountain,it has not yet been studied in regards to the glacial and periglacial processes;in fact,those dynamics have modified the mountain massifs in the *** complement the series of studies on glacial history in the high mountain environment of México,this study reconstructs the glacial cover and the periglacial environment of the volcano surface during the final stage of the Late Pleistocene based on climatic retrospective and through the identification of geomorphological *** findings indicate the existence of a large glacier(ice cap)that covered the northern,western,and southern slopes of the mountain;while in the eastern sector there were two small glaciers,one being of cirque type,and the other of valley *** current temperature conditions prevent the occurrence of permanent ice bodies;at the same time,it was found that the periglacial blockfields of the slopes is a legacy of the climatic conditions that prevailed at the end of Late Pleistocene.

关键词： Cofre de Perote Glacial cover Periglacial environment Climatic retrospective Palaeoclimatic modelling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Promotion of structural plasticity in area V2 of visual cortex prevents against object recognition memory deficits in aging and Alzheimer's disease rodents

引用

Neural Regeneration Research 2024年第8期19卷 1835-1841页

作者： Irene Navarro-Lobato Mariam Masmudi-Martín Manuel F.López-Aranda Juan F.López-Téllez Gloria delgado Pablo granados-Durán Celia Gaona-Romero Marta Carretero-Rey Sinforiano Posadas María E.Quiros-Ortega Zafar U.Khan Laboratory of Neurobiology Centro de Investigaciones Médico Sanitarias(CIMES)University of MalagaMalagaSpain Department of Medicine Faculty of MedicineUniversity of MalagaMalagaSpain Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas(CIBERNED) Institute of Health Carlos IIIMadridSpain the Donders Institute for Brain Cognition and Behaviour Radboud UniversityNijmegenThe Netherlands the Brain Metastasis Group National Cancer Research Centre(CNIO)MadridSpain the Department of Neurobiology University of California-Los AngelesLos AngelesCAUSA

Memory deficit,which is often associated with aging and many psychiatric,neurological,and neurodegenerative diseases,has been a challenging issue for *** till now,all potential drug candidates have failed to produce satisfa ctory ***,in the search for a solution,we found that a treatment with the gene corresponding to the RGS14414protein in visual area V2,a brain area connected with brain circuits of the ventral stream and the medial temporal lobe,which is crucial for object recognition memory(ORM),can induce enhancement of *** this study,we demonstrated that the same treatment with RGS14414in visual area V2,which is relatively unaffected in neurodegenerative diseases such as Alzheimer s disease,produced longlasting enhancement of ORM in young animals and prevent ORM deficits in rodent models of aging and Alzheimer’s ***,we found that the prevention of memory deficits was mediated through the upregulation of neuronal arbo rization and spine density,as well as an increase in brain-derived neurotrophic factor(BDNF).A knockdown of BDNF gene in RGS14414-treated aging rats and Alzheimer s disease model mice caused complete loss in the upregulation of neuronal structural plasticity and in the prevention of ORM *** findings suggest that BDNF-mediated neuronal structural plasticity in area V2 is crucial in the prevention of memory deficits in RGS14414-treated rodent models of aging and Alzheimer’s ***,our findings of RGS14414gene-mediated activation of neuronal circuits in visual area V2 have therapeutic relevance in the treatment of memory deficits.

关键词： behavioral performance brain-derived neurotrophic factor cognitive dysfunction episodic memory memory circuit activation memory deficits memory enhancement object recognition memory prevention of memory loss regulator of G protein signaling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of grain recrystallization on stir zone and mechanical property behavior of TRIP 780 steel

引用

Journal of Iron and Steel Research International 2020年第2期27卷 188-196页

作者： Gladys Perez-Medina hugo Lopez Argelia Miranda-Perez Eduardo Hurtado-delgado Postgraduate Studies Mexican Corporation in Materials ResearchSaltillo Coahuila 25290Mexico Materials Department University of Wisconsin-MilwaukeeMilwaukeeWI 53201USA

Electron backscatter diffraction(EBSD)and transmission electron microscopy were used to determine the presence of retained austenite and displacive-type phase transformation in the stir zone of friction stir welding(FSW).Severe plastic deformations occurred in the stir zone where there was an increase in the temperature attributed to the FSW process and subsequently a grain *** the recrystallization phenomena,the formation of grain evolution development in steels was resolved using *** addition,a tensile test was carried out in order to reveal the results of mechanical *** was found that the fracture zone occurred in the stir zone with an ultimate tensile strength of 587 MPa,a decrease of 267 MPa compared with that of the base *** this result,it is evident that the fracture exhibits numerous elongated dimples,distributed homogeneously,and certain locations contain cleavage fractures due to differences in the microstructure of the base *** profile tests of the welding regions were conducted,and the results showed that the stir zone was present with elevated hardness(near 350 HV).Characterization techniques revealed that the austenite-to-martensite transformation occurred in the stir zone,resulting in a loss of mechanical properties in the joint.

关键词： Friction welding Transformation-induced plasticity steel Stir zone Mechanical property Tensile test

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Seco-limonoid 11α,19β-dihydroxy-7-acetoxy-7- deoxoichangin promotes the resolution of Leishmania panamensisinfection

引用

Advances in Bioscience and Biotechnology 2013年第2期4卷 304-315页

作者： Diana granados-Falla Carlos Coy-Barrera Luis Cuca Gabriela delgado Immunotoxicology Research Group Department of Pharmacy Sciences Faculty Universidad Nacional de Colombia Bogotá Bo- gotá Colombia Natural Products Group School of Sciences Universidad Nacional de Colombia Bogotá Colombia

The high morbidity generated by the infection caused by parasites of the genus Leishmania, make of this infection into one of the vector-borne infectious diseases most relevant worldwide, which added to the fact that the drugs used for its treatment are far from be optimal and considering that prophylactic approaches (such as the development of a vaccine) still seems far from being achieved, make of the search for new therapeutic alternatives for safe and effective treatment of this disease one of the most accurate approaches to the control of this disease. In this study we evaluated the antileishmanial and immunomodu- latory activity of the compound 11α,19β-dihydroxy- 7-acetoxy-7-deoxoichangin (a seco-limonid molecule) through: 1) evaluation of its cytotoxicity over promastigotes and axenic amastigotes of L. (V) panamensis, 2) determination of its ability to induce the control of in vitro infection, using infected murine cells (J774.2) and human dendritic cells (hDCs), 3) quantifying the levels of pro-inflammatory cytokines, (iv) evaluating the expression of cell markers associated with hDCs maturation, and (v) determinating the production of nitric oxide free radicals (NO). In this regard, this seco-limonoid exhibited an antileishmanial activity represented in the reduction of in vitro infection in J774.2 cells and hDCs, with a EC50 of 7.9 μM (4.48 μg/mL) and 25.5 μM (14.39 μg/mL), respectively, and additionally, we observed an increase on the production of IL-12p70, TNF-α and NO, as also, in the number of hDCs HLA-DR-positive in treated infected hDCs. These findings suggest that anti-lei- shmanial activity of this compound could be associated with the potential “reactivation” of phagocytic cell that is “paralyzed” by the infection, generating an immune phenotype associated with protection.

关键词： Leishmaniasis Treatment Immunomodulation Seco-Limonoid

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ethnoedaphology as an Integrating Process between Academy and Peasant Knowledge in the Productive System of Coffee (Coffea arabica L.) of Southwestern Colombia

引用

Agricultural Sciences 2022年第10期13卷 1013-1030页

作者： Iván A. delgado-Vargas hugo Ferney Leonel Ángela A. Molina-Moreno Nicolás Ojeda Chávez Paula A. Pinta Paz Faculty of Agricultural Sciences University of Nari&#241 o Pasto Colombia

Community knowledge about agricultural land and its management constitutes a complex system of wisdom, with universal principles and categories similar or complementary to those used by modern soil science. However, soil management is only recognized from the point of view of agronomy and academia, covering problems in rural areas at the time of adopting agricultural alternatives. For this reason, peasant knowledge was characterized and related to scientific knowledge, in the valuation of land properties in the coffee (Coffea arabica L.) production system. The study was carried out in four villages in the municipality of Buesaco (Nari?o, Colombia), with humid pre-mountain forest conditions, an average temperature of 18?C, annual rainfall of 1400 mm, and an altitude of 1959 m. The study was carried out in the municipality of Buesaco (Nari?o, Colombia). Through field visits, priority was given to farms with coffee production systems under different types of shade. A semi-structured survey was applied to learn about the social, environmental, productive, ancestral, and cultural components, with the application of participatory methodologies allowed to learn about traditional management and practices in the soil component. The results allowed us to identify four types of production systems from coffee without shade to coffee in association with different multipurpose woody perennials and mosses. Diverse dynamics of crop and land management are presented. Several references were found to differentiate land types such as color, texture, production and fertility, being characteristics that are associated to classify soil quality and make management decisions and type of fertilization. Through the perception of the farmers, six land classes with different characteristics were identified, relating the characterization with what was obtained in the chemical analysis of lands. It can be concluded that the perception of coffee growers, dark shades in the land representing bette

关键词： Ethnoedaphology Local Knowledge Scientific Knowledge Local Referents Land Properties Coffee Cultivation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Device-associated infection rates, mortality, length of stay and bacterial resistance in intensive care units in Ecuador: International Nosocomial Infection Control Consortium's findings

引用

World Journal of Biological Chemistry 2017年第1期8卷 95-101页

作者： Estuardo Salgado Yepez Maria M Bovera Victor D Rosenthal hugo A González Flores Leonardo Pazmino Francisco Valencia Nelly Alquinga Vanessa Ramirez Edgar Jara Miguel Lascano Veronica delgado Cristian Cevallos Gasdali Santacruz Cristian Pelaéz Celso Zaruma Diego Barahona Pinto Clínica la Merced Hospital de los Valles International Nosocomial Infection Control Consortium

AIM To report the results of the International Nosocomial Infection Control Consortium(INICC) study conducted in Quito, *** A device-associated healthcare-acquired infection(DAHAI) prospective surveillance study conducted from October 2013 to January 2015 in 2 adult intensive care units(ICUs) from 2 hospitals using the United States Centers for Disease Control/National Healthcare Safety Network(CDC/NHSN) definitions and INICC methods. RESULTS We followed 776 ICU patients for 4818 bed-days. The central line-associated bloodstream infection(CLABSI) rate was 6.5 per 1000 central line(CL)-days, the ventilator-associated pneumonia(VAP) rate was 44.3 per 1000 mechanical ventilator(MV)-days, and the catheterassociated urinary tract infection(CAUTI) rate was 5.7 per 1000 urinary catheter(UC)-days. CLABSI and CAUTI rates in our ICUs were similar to INICC rates [4.9(CLABSI) and 5.3(CAUTI)] and higher than NHSN rates [0.8(CLABSI) and 1.3(CAUTI)]- although device use ratios for CL and UC were higher than INICC and CDC/NSHN's ratios. By contrast, despite the VAP rate was higher than INICC(16.5) and NHSN's rates(1.1), MV DUR was lower in our ICUs. Resistance of A. baumannii to imipenem and meropenem was 75.0%, and of Pseudomonas aeruginosa to ciprofloxacin and piperacillin-tazobactam was higher than 72.7%, all them higher than CDC/NHSN rates. Excess length of stay was 7.4 d for patients with CLABSI, 4.8 for patients with VAP and 9.2 for patients CAUTI. Excess crude mortality in ICUs was 30.9% for CLABSI, 14.5% for VAP and 17.6% for CAUTI. CONCLUSION DA-HAI rates in our ICUs from Ecuador are higher than United States CDC/NSHN rates and similar to INICC international rates.

关键词： Ventilator-associated pneumonia Catheter-associated urinary tract infection Healthcare-associated infection Antibiotic resistance Developing countries Intensive care unit Surveillance Central line-associated bloodstream infections Hospital infection

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ethnoedaphology as an Integrating Process between Academy and Peasant Knowledge in the Productive System of Coffee (Coffea arabica L.) of Southwestern Colombia

引用

Agricultural Sciences（农业科学） 2022年第10期

作者： iván a. delgado-vargas hugo ferney leonel ángela a. molina-moreno nicolás ojeda chávez paula a. pinta paz

来源：博看期刊评论

在线全文

博看期刊

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：