检索结果-南通市图书馆

Experimental analysis of infragravity waves in two eroded microtidal beaches

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2017年第5期36卷 31-43页

作者： MARIO Conde-Frias LUIS Otero juan camilo Restrepo juan Carlos Ortiz Geosciences Research Group GE04 Department of PhysicsUniversidad del NorteBarranquilla 081007Colombia

This work aims to contribute to the characterization and understanding ofinfragravity waves on two beaches with erosion problems. For this reason, we have used an array of ADCP and a pressure sensor to measure wave parameters and pressure inside and outside of the surf zone during the dry and rainy period in the beaches of Galerazamba and Manzanillo del Mar （both dissipative and eroded beaches） located in the Colombian Caribbean coast. Based on these measurements, we have carried out a spectral analysis in order to identify the frequency components that characterize the wave and its energy; thus, we identified the characteristic frequencies of iufragravity waves to finally filter the infragravity signal on each beach in different seasonal periods. Among the results of the Welch spectrum applied to surface elevation time series, we found that, the frequencies＇ energy of the sea-swell band decreases due to bottom friction and wave breaking as the wave approaches the shore, while the frequencies＇ energy of the infragravity band increases significantly. In addition, for the wavelet analysis, we could observe how the energy of the infragravity band, especially the lowest frequencies gain energy as the waves approaches the coast. Furthermore, based on the infragravity wave obtained from the extreme wave event registered during the field campaign we can conclude that the contribution of this signal is important in the erosion problems presented in the beaches of Galerazamba and Manzanillo del Mar. Finally, these results show the need to realize other studies that allow us to understand deeply, the role of infragravity waves on the morphological changes that occurs in these beaches.

关键词： infragravity waves long waves experimental analysis fourier analysis wavelet transform

Self-deception can evolve under appropriate costs

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2015年第2期61卷 382-396页

作者： juan camilo RAMiREZ James A. R. MARSHALL Department of Computer Science University of Sheffield Sheffield S 1 4DP United Kingdom

Apparent biases in decision making by animals, including humans, seem to present an evolutionary puzzle, since one would expect decisions based on biased （unrealistic） information to be suboptimal. Although cognitive biases are hard to diag- nose in real animals （Marshall et al., 2013b）, we investigate Trivers＇ proposal that individuals should self-deceive first in order to better deceive others （Trivers, 2011）. Although this proposal has been scrutinized extensively （Bandura et al., 2011） it has not been formally modelled. We present the first model designed to investigate Trivers＇ proposal. We introduce an extension to a re- cent model of the evolution of self-deception （Johnson and Fowler, 2011）. In the extended model individuals make decisions by taking directly into account the benefits and costs of each outcome and by choosing the course of action that can be estimated as the best with the information available. It is shown that in certain circumstances self-deceiving decision-makers are the most evolutionarily successful, even when there is no deception between these. In a further extension of this model individuals addi- tionally exhibit deception biases and Trivers＇ premise （that effective deception is less physiologically costly with the aid of self-deception） is incorporated. It is shown that under Trivers＇ hypothesis natural selection favors individuals that self-deceive as they deceive others .

关键词： Self-deception Deception Overconfidence Cognitive biases Optimal decision-making Optimal behavior

Suspended sediment transport in the Magdalena River(Colombia,South America):Hydrologic regime,rating parameters and effective discharge variability

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2016年第01期31卷 25-35页

作者： Aldemar Higgins juan camilo Restrepo juan Carlos Ortiz Jorge Pierini Luis Otero (UNS-CIC-CCT)

The Magdalena River has the greatest length（1612 km）and drainage area（257400 km2）of any river system in Colombia,and its watershed occupies 24%of the Colombian *** river originates in the Andean Cordillera at an elevation of 3685 m and flows to its mouth in the Caribbean Sea（Bocas de Cenizas）.For this study,information on daily flow discharge（Q）,suspended sediment transport(Qsand mean suspended sediment concentration（Cs）from 1990-2010 for the Magdalena River,based on measurements at the Caiamar gauging station（the closest station to the mouth）,was provided by the Institute of Hydrology,Meteorology and Environmental Studies of Colombia（IDEAM in Spanish）.The mean annual suspended sediment load was 169±73×10～6tyr-1for the period from 1990-1999 and145±47×10～6 t yr1for the period from 2000-2010,amounting to a 14%reduction in the suspended sediment transport rate between the two *** sediment rating curve（Qs=aQb）was also evaluated for these two periods（1990-1999 and 2000-2010）.An analysis of the regression coefficients（a.b）for the two periods showed a decrease in b and an increase in a after 1999,which coincides with a decrease in suspended sediment *** change might be attributed to natural factors,including the accumulation of sediment in the Depresion Momposina and variation in hydro-climatological patterns in the Caribbean *** in effective transport were confirmed using three methods（Log-Normal and Normal distribution,and magnitude-frequency histogram）for the study period.

关键词： Suspended sediment transport Magdalena River Transport regime Effective discharge Sediment rating curve

Analysis of the role of diffraction in topographic site effects using boundary element techniques

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Earthquake Science 2013年第5期26卷 341-350页

作者： juan Gomez Doriam Restrepo juan Jaramillo camilo Valencia Departamento de Ingeniería Civil Universidad EAFITMedellín Colombia

The role played by the diffraction field on the problem of seismic site effects is studied. For that purpose we solve and analyze simple scattering problems under P and SV in-plane wave assumptions, using two well known direct boundary-element-based numerical methods. After establishing the difference between scattered and diffracted motions, and introducing the concept of artificious and physically based incoming fields, we obtain the amplitude of the Fourier spectra for the diffracted part of the response： this is achieved after establishing the connection between the spatial distribution of the transfer function over the studied simple topographies and the diffracted field. From the numerical simulations it is observed that this diffracted part of the response is responsible for the amplification of the surface ground motions due to the geometric effect. Furthermore, it is also found that the diffraction field sets in a fingerprint of the topographic effect in the total ground motions. These conclusions are further supported by observations in the time-domain in terms of snapshots of the propagation patterns over the complete computational model. In this sense the geometric singularities are clearly identified as sources of diffraction and for the considered range of dimensionless frequencies it is evident that larger amplifications are obtained for the geometries containing a larger number of diffraction sources thus resulting in a stronger topographic effect. The need for closed-form solutions of canonical problems to construct a robust analysis method based on the diffraction field is identified.

关键词： Seismic site effects Topographiceffects Elastic wave scattering Diffractionof in-plane waves

An unsupervised pattern recognition methodology based on factor analysis and a genetic-DBSCAN algorithm to infer operational conditions from strain measurements in structural applications

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第2期34卷 165-181页

作者： juan Carlos PERAFAN-LOPEZ Julian SIERRA-perez Grupo de Investigacion en Ingenieria Aeroespacial Universidad Pontificia BolivarianaCircular 170-01Medellin 050031Colombia

Structural Health Monitoring(SHM) suggests the use of machine learning algorithms with the aim of understanding specific behaviors in a structural system. This work introduces a pattern recognition methodology for operational condition clustering in a structure sample using the well known Density Based Spatial Clustering of Applications with Noise(DBSCAN) *** methodology was validated using a data set from an experiment with 32 Fiber Bragg Gratings bonded to an aluminum beam placed in cantilever and submitted to cyclic bending loads under 13 different operational conditions(pitch angles). Further, the computational cost and precision of the machine learning pipeline called FA + GA-DBSCAN(which employs a combination of machine learning techniques including factor analysis for dimensionality reduction and a genetic algorithm for the automatic selection of initial parameters of DBSCAN) was measured. The obtained results have shown a good performance, detecting 12 of 13 operational conditions, with an overall precision over 90%.

关键词： Clustering DBSCAN Factor analysis FBGs Pattern recognition Strain field

Geographic-Scale Coffee Cherry Counting with Smartphones and Deep Learning

在线全文

学校读者我要写书评

暂无评论

Plant Phenomics 2024年第2期6卷 390-400页

作者： juan camilo Rivera-Palacio Christian Bunn Eric Rahn Daisy Little-Savage Paul Günter Schmidt Masahiro Ryo Leibniz Centre for Agricultural Landscape Research(ZALF) Müncheberg15374Germany Alliance of Bioversity International and CIAT Rome00153Italy Brandenburg University of Technology Cottbus-Senftenberg Cottbus03046Germany Producers Direct LondonE28EXUK

Deep learning and computer vision,using remote sensing and drones,are 2 promising nondestructive methods for plant monitoring and ***,their applications are infeasible for many crop systems under tree canopies,such as coffee crops,making it challenging to perform plant monitoring and phenotyping at a large spatial scale at a low *** study aims to develop a geographic-scale monitoring method for coffee cherry counting,supported by an artificial intelligence(AI)-powered citizen science *** approach uses basic smartphones to take a few pictures of coffee trees;2,968 trees were investigated with 8,904 pictures in Junin and Piura(Peru),Cauca,and Quindio(Colombia)in 2022,with the help of nearly 1,000 smallholder coffee ***,we trained and validated YOLO(You Only Look Once)v8 for detecting cherries in the dataset in *** average number of cherries per picture was multiplied by the number of branches to estimate the total number of cherries per *** model's performance in Peru showed an R^(2)of *** the model was tested in Colombia,where different varieties are grown in different biogeoclimatic conditions,the model showed an R^(2)of *** overall performance in both countries reached an R^(2)of *** results suggest that the method can be applied to much broader scales and is transferable to other varieties,countries,and *** our knowledge,this is the first AI-powered method for counting coffee cherries and has the potential for a geographic-scale,multiyear,photo-based phenotypic monitoring for coffee crops in low-income countries worldwide.

关键词： geographic learning scale coffee deep with cherry counting smartphones

2-Cys Peroxiredoxins Participate in the Oxidation of Chloroplast Enzymes in the Dark

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2018年第11期11卷 1377-1388页

作者： Valle Ojeda juan Manuel perez-Ruiz Francisco Javier Cejudo Instituto de Bioquimica Vegetaly Fotosintesis Universidad de Sevilla and Consejo Superior de lnvestigaciones CientificasAvenida Americo Vespucio 4941092SevillaSpain

Most redox-regulated chloroplast enzymes are reduced during the day and oxidized during the *** the reduction mechanism of light-dependent enzymes is well known,the mechanism mediating their oxidation in the dark remains *** thiol-dependent peroxidases,2-Cys peroxiredoxins (Prxs),play a key role in light-dependent reduction of chloroplast *** transfer reducing equivalents of thiols to hydrogen peroxide,suggesting the participation of these peroxidases in enzyme oxidation in the ***,we have addressed this issue by analyzing the redox state of well-known redox-regulated chloroplast enzymes in response to darkness in Arabidopsis thaliana mutants deficient in chloroplastlocalized Prxs (2-Cys Prxs A and B,Prx ⅡE,and Prx Q).Mutant plants lacking 2-Cys Prxs A and B,and plants overexpressing NADPH-dependent thioredoxin (Trx) reductase C showed delayed oxidation of chloroplast enzymes in the *** contrast,the deficiencies of Prx ⅡE or Prx Q exerted no *** vitro assays allowed the reconstitution of the pathway of reducing equivalents from reduced fructose 1,6-bisphosphatase to hydrogen peroxide mediated by Trxs and 2-Cys *** together,these results suggest that 2-Cys Prxs participate in the short-term oxidation of chloroplast enzymes in the dark.

关键词： chloroplast enzyme oxidation peroxiredoxin thioredoxin hydrogen peroxide darkness

Clinical outcomes of patterned laser trabeculoplasty as adjuvant therapy in open angle glaucoma and ocular hypertension

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第4期11卷 635-640页

作者： Gustavo Espinoza Leonardo Castellanos Ignacio Rodriguez-Una Paul Anthony Camacho juan camilo Parra Fundacion Oftalmologica de Santander FOSCAL FloridablancaSantanderColombia Instituto Oftalmologico Fernandez-Vega University of OviedoOviedoAsturias 33012Spain Facultad de Salud Universidad Autonoma de BucaramangaBucaramangaSantanderColombia

AIM： To assess the efficacy and safety of patterned laser trabeculoplasty（PLT） as an adjunctive treatment in open angle glaucoma（OAG） or ocular hypertension（OHT） patients who were under antiglaucoma medical ***： This study was a retrospective review of primary or secondary OAG patients and OHT patients with medically uncontrolled（≥18 mm Hg） intraocular pressure（IOP） who underwent 360o PLT from June 2016 to August 2016. Follow-up visits at week 1, and 1, 3 and 6 mo were performed. IOP, best corrected visual acuity（BCVA）, complications and eye drop glaucoma medication were recorded at each follow-up visit. Success was defined as IOP reduction ≥20% from baseline. RESULTS： Forty-one eyes of 25 patients were included in this study. Pre-treatment mean IOP was 20.2±1.6 mm Hg. After PLT, IOP was 19.3±5.2, 16.1±2.7, 17.1±3.7 and 16.3±3.5 mm Hg,at 1 wk, 1, 3 and 6 mo, respectively. IOP reduction from baseline was statistically significant from the first month, remaining stable at 6 mo（P〈0.001）. PLT success at 6 mo of follow-up was 48.78%. The number of glaucoma medication per eye（P=0.10） and the mean BCVA both remained constant（P=0.37）. Complications included transient IOP spikes in 4 eyes（9.8%） and peripheral anterior synechiae in 7 eyes（17.1%）. CONCLUSION： PLT is an effective and safe method for the management of patients with OHT or OAG as an adjunctive therapy. Additional larger studies should be designed to verify the long-term stability of IOP reduction with this laser technology.

关键词： glaucoma intraocular pressure laser ocular hypertension trabeculoplasty

Identifcation of Immunity-related Genes in Arabidopsis and Cassava Using Genomic Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2013年第6期11卷 345-353页

作者： Luis Guillermo Leal A'lvaro perez Andre's Quintero A'ngela Bayona juan Felipe Ortiz Anju Gangadharan David Mackey camilo Lo'pez Liliana Lo'pez-Kleine Department of Statistics Universidad Nacional de Colombia Department of Biology Universidad Nacional de Colombia Department of Molecular Genetics The Ohio State University

Recent advances in genomic and post-genomic technologies have provided the opportu- nity to generate a previously unimaginable amount of information. However, biological knowledge is still needed to improve the understanding of complex mechanisms such as plant immune responses. Better knowledge of this process could improve crop production and management. Here, we used holistic analysis to combine our own microarray and RNA-seq data with public genomic data from Arabidopsis and cassava in order to acquire biological knowledge about the relationships between proteins encoded by immunity-related genes （IRGs） and other genes. This approach was based on a kernel method adapted for the construction of gene networks. The obtained results allowed us to propose a list of new IRGs. A putative function in the immunity pathway was predicted for the new IRGs. The analysis of networks revealed that our predicted IRGs are either well documented or recognized in previous co-expression studies. In addition to robust relationships between IRGs, there is evidence suggesting that other cellular processes may be also strongly related to immunity.

关键词： Arabidopsis Cassava Functional gene prediction Genomic data Kernel canonical correlation ajalysi Plant immunity