检索结果-南通市图书馆

Journal of Environmental Science and Engineering(A) 2014年第2期3卷 87-105页

作者： Jorge Bluhm Gutierrez1 Alicia Esparza Martinez Ernesto Patricio Nufiez Pena Felipe de Jesus Escalona Alcazar Santiago Valle Rodriguez josefina huerta garcia Academic Unit of Earth Sciences University Autonomous of Zacatecas Zacatecas 98058 Mexico Academic Unit of Culture University Autonomous of Zacateeas Zacatecas 98058 Mexico Academic Unit of Biological Sciences University Autonomous of Zacatecas Zacatecas 98058 Mexico

PCA （principal component analysis）, CCA （canonical correlation analysis） and PLSR （partial least squares regression） are powerful water quality modeling methods that provide better results than other classical ones such as multiple lineal regression. In this work they were used to model four water quality parameters at the Amadorio Reservoir （Alicante, Spain）, namely： water temperature, dissolved oxygen, pH and conductivity. The main purpose of this study was to predict the future quality of the water and, thus improve its management. Raw data correspond to daily values of mean wind speed, mean wind direction, maximum wind speed, mean, minimum and maximum air temperature, number of hours below 7 ~C, relative humidity, global solar radiation, total precipitation, evapotranspiration, exploitation volume, inflow, outflow, filtration, depth and Julian day. Two years were considered （2004-2005） to get the calibration （186 days, 4,401 registrations） and validation （185 days, 4,573 registrations） datasets. Models were developed using either all the variables or a reduced subset; furthermore, PLSR yielded the best results.

关键词： Water quality management canonical correlation analysis partial least squares

Depletion of an Artificial Seed Bank of Palmer Amaranth (<i>Amaranthus palmeri</i>) over Four Years of Burial

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2014年第11期5卷 1599-1606页

作者： Prashant Jha Jason K. Norsworthy josefina garcia Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA Southern Agricultural Research Center Montana State University Huntley USA

An artificial seed bank study was conducted at Pendleton, SC, USA, to investigate the persistence of Palmer amaranth seeds buried uniformly across a 10-cm depth in soil inside polyvinyl chloride (PVC) cylindrical pipes over 4 years. The experiment was conducted using a split-plot design, with year as the main plot factor and with or without soil disturbance (shallow tillage to a depth of 10 cm) as the subplot factor. Annual soil disturbance through tillage in the spring stimulated emergence during the first and second year after burial. A total of 0.5% to 0.8% of the seed bank emerged during the 4-yr burial period, and 99% or more of the 4-yr total emergence occurred during the first two years of burial. Seeds retrieved from 0 to 5 cm and 5 to 10 cm depths did not differ in viability. Soil disturbance influenced the decline of the artificial seed bank at least in the first year, with fewer viable seeds remaining in annually-disturbed plots. Regardless of soil disturbance, a small fraction of seeds (0.01% to 0.03% of original seed bank) remained viable in the soil after four years of burial. In conclusion, Palmer amaranth seeds buried across a 10 cm soil depth in the artificial seed bank had low persistence, which implies that burial may aid management of the weed seed bank.

关键词： Burial Dormancy Persistence Soil Seed Bank Seedling Emergence Tillage

Reciprocal Effects of Plant-Soil Relationships at Two Spatial Scales in a Semiarid Land of Central Mexico

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Agricultural Science and Technology(A) 2012年第1期2卷 71-79页

作者： Francisco Martin huerta-Martinez Alejandro Mufioz-Urias Cecilia Neri-Luna Claudia Aurora Uribe-Mu Edmundo garcia-Moya Departamento de Ecologia Centro Universitario de Ciencias Biol6gicas y Agropecuarias Universidad de Guadalajara Zapopan Jalisco C.P. Mexico Instituto de Recursos Naturales Colegio de Postgraduados Montecillo Edo. de Mexico C.P 56230 Mexico

We studied the influence of soil heterogeneity on plant community structure in a semiarid region of Central Mexico using Bray-Curtis Ordination. The results showed that some edaphic factors, such as soil depth, organic matter, and potassium and calcium content, explained 80% of the total variation in structure of the studied communities. We found that soil resources were heterogeneously distributed in the study area, indicating that the edaphic variables considered in this study explain the existing plant community variability, moreover the presence of some shrubs as Krameria cytisoides influences the soil properties, suggesting that there is a reciprocal effect between plant and soil.

关键词： Ordination vegetation soil Chihuahuan Desert.

An Integrated ISFET pH Microsensor on a CMOS Standard Process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Sensor Technology 2013年第3期3卷 57-62页

作者： Francisco López-huerta Rosa María Woo-garcia Miguel Lara-Castro Johan Jair Estrada-López Agustín Leobardo Herrera-May Faculty of Electronics Sciences Meritorious Autonomous University of Puebla Puebla Mexico Faculty of Mathematics Autonomous University of Yucatán Mérida Mexico Research Center for Micro and Nanotechnology University of Veracruz Veracruz Mexico

We present the design and integration of a nine-pH microsensor array on a single silicon substrate with its own signal readout circuit, integrated in a 0.6-μm commercial standard complementary metal oxide semiconductor (CMOS) process. An ion sensitive field effect transistor (ISFET) has been used as pH microsensor and an instrumentation amplifier as the read-out circuit. The ISFET structure is conformed by the channel length and ratio of MOS transistor, gate extended and the selective membrane, for which silicon nitride (Si3N4) is employed as an ion selective element. The complete design includes shielding around the pH microsensor and the readout circuit to avoid leakage of current to the substrate. The readout circuit is composed by three operational amplifiers and resistances that form the instrumentation amplifier, with a ±2.5 V bias has a 50 dB gain, power supply rejection ratio (PSSR) of 120 dB and common mode rejection ratio (CMRR) of 127 dB. The complete system is integrated in a 1.12 mm2 silicon area;it presents a 59 mV/pH linearity, within a concentration range of 2 to 12 of pH level, making it a good alternative for biological or medical applications.

关键词： CMOS Instrumentation Amplifier ISFET pH

Isolation and Progeny Transmission of Non-Temperature-Sensitive MS-H Vaccine Strains of Mycoplasma synoviae from Temperature-Sensitive MS-H-Vaccinated Laying Breeder Hens

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food and Nutrition Sciences 2023年第7期14卷 579-588页

作者： Victor M. Petrone-garcia Raquel López-Arellano Inkar Castellanos-huerta Saeed El-Ashram Ebtesam Al-Olayan Danielle Graham Guillermo Tellez-Isaias Departamento de Ciencias Pecuarias Universidad Nacional Autónoma de México (UNAM) Cuautitlan Izcalli Estado de México México Laboratorio No 5: LEDEFAR Unidad de Investigacion Multidisciplinaria Facultad de Estudios Superi-ores Cuautitlan UNAM Cuautitlan Izcalli Estado de México México Department of Poultry Science University of Arkansas Fayetteville USA Department of Zoology Faculty of Science Kafrelsheikh University Kafr El-Sheikh Egypt Department of Zoology College of Science King Saud University Riyadh Saudi Arabia

This pilot study reports the vertical transmission and reverse thermosensitivity of the MS-H vaccine strain of Mycoplasma synoviae (MS) by RAPD in commercial breeders and their progeny. At two weeks of age, breeders were vaccinated with the ts+ MS-H strain. At 9 weeks of age, an outbreak of infectious synovitis (IS) was detected in the progeny. Tracheal swab samples were collected from breeders at 24, 39, 48, and 70 weeks of age. At 9 weeks, pullets swab from the elbow joints were collected. RAPD was performed on the isolates at 39.5°C, and the same ts- MS-H strains were identified in the breeder hens and their progeny. Tracheal swabs from breeder hens were negative to MS isolation at 37°C and 39.5°C at 24- and 39-weeks. MS isolation was recovered from tracheal swabs from 9/10 and 10/10 breeders at 48- and 70- week. At 9 weeks of age in the progeny, MS was isolated from tracheal swabs of 10/10 from non-IS pullets. MS was isolated from 9/10 joints samples. The isolates from breeder hens and their progeny showed non-significant differences in five antimycoplasmic MIC100 values;otherwise, enrofloxacin presented a significant difference in MIC100 value (p < 0.05). This investigation demonstrated the reversal of the thermosensitivity, pathogenicity, and vertical transmission of the MS-H strain. Consequently, it is crucial to contemplate the danger of reversing pathogenicity and transmission to progeny when applying the MS-H vaccine strain.

关键词： Vertical Transmission Thermosensitivity Mycoplasma synoviae RAPD Vax-Safe®

Landscape genetics reveals inbreeding and genetic bottlenecks in the extremely rare short-globose cacti Mammillaria pectinifera (Cactaceae) as a result of habitat fragmentation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2017年第1期39卷 13-19页

作者： Reyna Maya-garcia Santiago Arizaga Pablo Cuevas-Reyes Juan Manuel Penaloza-Ramirez Victor Rocha Ramirez Ken Oyama Facultad de Biologia Universidad Michoacana de San Nicolas de Hidalgo Mexico Escuela Nacional-de Estudios Superiores Unidad Morelia UNAM Antigua Carretera a Pdtzcuaro 8701 Colonia Ex-Hacienda de SanJose de la Huerta58190 Morelia Michoacan Mexico

Mammillaria pectinifera is an endemic, short-globose cactus species, included in the IUCN list as a threatened species with only 18 remaining populations in the Tehuacfin-Cuicatlan Valley in central Mexico. We evaluated the population genetic diversity and structure, connectivity, recent bottlenecks and population size, using nuclear microsatellites. M. pectinifera showed high genetic diversity but some evidence of heterozygote deficiency （F15）, recent bottlenecks in some populations and reductions in population size. Also, we found low population genetic differentiation and high values of connectivity for M. pectinifera, as the result of historical events of gene flow through pollen and seed dispersal. M. pectinifera occurs in sites with some degree of disturbance leading to the isolation of its populations and decreasing the levels of gene flow among them. Excessive deforestation also changes the original vegetation damaging the natural habitats. This species will become extinct if it is not properly preserved. Furthermore, this species has some ecological features that make them more vulnerable to disturbance such as a very low growth rates and long life cycles. We suggest in situ conservation to prevent the decrease of population sizes and loss of genetic diversity in the natural protected areas such as the Tehuacan-Cuicatlan Biosphere Reserve. In addition, a long-term ex situ conservation program is need to construct seed banks, and optimize seed germination and plant establishment protocols that restore disturbed habitats. Furthermore, creating a supply of living plants for trade is critical to avoid further extraction of plants from nature.

关键词： MammiUaria pectiniferaNuclear SSRGenetic diversityRecent bottlenecksEffective population size

Essential Oils as an Alternative to Antibiotics to Reduce the Incidence and Severity of Necrotic Enteritis in Broiler Chickens: A Short Review

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

Food and Nutrition Sciences 2023年第3期14卷 233-257页

作者： Makenly E. Coles Brittany D. Graham Juan D. Latorre Victor M. Petrone-garcia Xochitl Hernandez-Velasco Inkar Castellanos-huerta Xiaolun Sun Billy M. Hargis Saeed El-Ashram Awad A. Shehata Guillermo Tellez-Isaias Department of Poultry Science University of Arkansas Agricultural Experiment Station Fayetteville USA Facultad de Estudios Superiores Cuautitlan Universidad Nacional Autonoma de Mexico (UNAM) Cuautitlan Izcalli Estado de Mexico Mexico Departamento de Medicina y Zootecnia de Aves Facultad de Medicina Veterinaria y Zootecnia (FMVZ) UNAM Cd. de Mexico Mexico Programa de Maestría y Doctorado en Ciencias de la Producción y de la Salud Animal FMVZ UNAM Cd. de Mexico Mexico College of Life Science and Engineering Foshan University Foshan China Prophy-Institute for Applied Prophylaxis Bönen Germany

Due to the removal of antibiotic growth promoters (AGPs) and consumer pressure for antibiotic-free (ABF) or no antibiotics ever (NAE) poultry production, there is a need for sustainable alternatives to prevent disease in commercial poultry operations. Without AGPs, there has been a rise in diseases that were traditionally controlled by subtherapeutic levels of antibiotics in the diet. This has impacted the health of commercial poultry and has been a significant cost to poultry producers. To mitigate this, the industry has started to investigate alternatives to antibiotics to treat these forthcoming health issues, such as necrotic enteritis (NE). NE is an enteric disease caused by an over proliferation of toxigenic Clostridium perfringens (CP) in the gastrointestinal tract. Although CP is a commensal in the avian intestinal tract, dysbiosis caused by inflammation and impaired intestinal integrity facilitates uncontrolled replication of CP. Infectious agents, such as Eimeria maxima, appear to be a predominant predisposing factor that promotes NE. However, non-infectious stressors, including dietary changes, have also been associated with NE to some degree. As a result of increased pressure to restrict the use of antibiotics, there is a need for research evaluating the efficacy of alternatives, such as plant-derived essential oils, as potential tools to mitigate NE in commercial poultry flocks. The aim of this study is to review the effects of essential oils as an alternative to antibiotics to reduce the incidence and severity of necrotic enteritis in broiler chickens.

关键词： Necrotic Enteritis Essential Oils Chickens Clostridium perfringens Alternatives to Antibiotics