Pub Date : 2020-12-30DOI: 10.11144/JAVERIANA.SC25-3.SOZP
Jefersson A. López, R. Toro, A. R. Bohórquez, J. H. Quintana, J. Henao
A Na-P zeolite was synthesized and subjected to ion exchange with Ca2+, Cu2+, Al3+, and In3+, and supported with H+/NH4Cl (NH4-P) by in situ reaction of EtOH and NH4Cl. All the exchanged zeolites showed catalytic activity in the ABB’ Povarov reaction. However, zeolite NH4-P promoted a better yield. In all reactions two products were obtained, 2,6-dimethyl-4-(2-oxopyrrolidin-1-yl)-1,2,3,4-tetrahydroquinoline and 1-(1-(4-methylphenylamino)ethyl)pyrrolidin 2-one. Synthesis using zeolite P as catalyst proves to be a simple method with high yields, short reaction times and easy preparation. The catalyst can be recovered by filtration and reused up to three times in good yields.
{"title":"Synthesis of zeolites P and evaluation of their activity as new and reusable heterogeneous catalysts in a three-component ABB’ Povarov model reaction","authors":"Jefersson A. López, R. Toro, A. R. Bohórquez, J. H. Quintana, J. Henao","doi":"10.11144/JAVERIANA.SC25-3.SOZP","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-3.SOZP","url":null,"abstract":"A Na-P zeolite was synthesized and subjected to ion exchange with Ca2+, Cu2+, Al3+, and In3+, and supported with H+/NH4Cl (NH4-P) by in situ reaction of EtOH and NH4Cl. All the exchanged zeolites showed catalytic activity in the ABB’ Povarov reaction. However, zeolite NH4-P promoted a better yield. In all reactions two products were obtained, 2,6-dimethyl-4-(2-oxopyrrolidin-1-yl)-1,2,3,4-tetrahydroquinoline and 1-(1-(4-methylphenylamino)ethyl)pyrrolidin 2-one. Synthesis using zeolite P as catalyst proves to be a simple method with high yields, short reaction times and easy preparation. The catalyst can be recovered by filtration and reused up to three times in good yields.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49370997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.11144/JAVERIANA.SC25-3.DPBO
Carolina Ramos-Montaño, L. J. Vanegas-Cano, Nancy Milena Cárdenas-Avella, Karen Lizeth Pulido-Herrera, Sindy Paola Buitrago-Puentes
The regenerative success of generalist and specialist species may be due to differences in their physiology. Measurements of stomatal conductance (gS) provide an efficient way to infer immediate physiological responses of plants to diurnal environment variation. Radiation, air temperature, and relative humidity were measured in the Colombian Amazon rainforest, to identify the extreme environmental conditions that limit the gS of seedlings in three site types: small gap, open forest, and closed forest. We hypothesized that the diurnal physiological performance of generalist species must be plastic in these three environments. Morphological traits, gS, and leaf temperature were evaluated in seedlings of four species: one generalist, common to all sites, and one specialist from each site. The gap site was warmer and more irradiated than the other two sites, which caused several midday physiological depressions, limited seedling survival, and facilitated the specialized strategy. Leaf and air temperatures were strong determinants of overall gS. The generalist species was physiologically plastic and, at some hours of the day, more efficient than the specialists from open forest andclosed forests. This factor interplay could allow the coexistence of both types of plants.
{"title":"Diurnal physiological behavior of seedlings in the Amazon rainforest: generalist versus specialist species of shade and sun","authors":"Carolina Ramos-Montaño, L. J. Vanegas-Cano, Nancy Milena Cárdenas-Avella, Karen Lizeth Pulido-Herrera, Sindy Paola Buitrago-Puentes","doi":"10.11144/JAVERIANA.SC25-3.DPBO","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-3.DPBO","url":null,"abstract":"The regenerative success of generalist and specialist species may be due to differences in their physiology. Measurements of stomatal conductance (gS) provide an efficient way to infer immediate physiological responses of plants to diurnal environment variation. Radiation, air temperature, and relative humidity were measured in the Colombian Amazon rainforest, to identify the extreme environmental conditions that limit the gS of seedlings in three site types: small gap, open forest, and closed forest. We hypothesized that the diurnal physiological performance of generalist species must be plastic in these three environments. Morphological traits, gS, and leaf temperature were evaluated in seedlings of four species: one generalist, common to all sites, and one specialist from each site. The gap site was warmer and more irradiated than the other two sites, which caused several midday physiological depressions, limited seedling survival, and facilitated the specialized strategy. Leaf and air temperatures were strong determinants of overall gS. The generalist species was physiologically plastic and, at some hours of the day, more efficient than the specialists from open forest andclosed forests. This factor interplay could allow the coexistence of both types of plants.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47761847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-22DOI: 10.11144/JAVERIANA.SC25-3.COAR
Deisy Lorena Guerrero Ceballos, Edith Mariela Burbano Rosero, E. Ibargüen-Mondragón
Bacterial resistance to antibiotics is one of the largest medical concerns worldwide.One of the bacteria of critical priority is E. coli, since it presents different resistance mechanisms and some of its strains have evolved resistance to beta-lactam antibiotics. We characterized 32 antibiotic resistant bacterial isolates from confirmed cases of urinary tract infections from an array of patients in Nariño, southern Colombia. Macro and microscopic descriptions of the 32 clinical isolates were conducted. Resistance profiles, biochemical, and molecular characterization (via 16S rRNA gene sequencing, ERIC-PCR, and resistance genes) were performed. All the isolates were identified as E. coli and had resistance to beta-lactams, aminoglycosides, and fluoroquinolones. This resistance was related to plasmids carryingthebla TEM, blaSHV1, and blaCTXM1genes.There were significant differences between the resistance proportions of the samples (p value:0.0000), mainly to penicillin, cefotoxin, and imipenem. Using ERIC-PCR, four clonal states were evidenced that corroborate a degree of genetic differentiation with in the isolate set.Antibiotic resistance observed in the isolates is associated with resistance genes present in the bacterial chromosome and plasmids.
{"title":"Characterization of antibiotic-resistant Escherichia coli associated with urinary tract infections in Southern Colombia","authors":"Deisy Lorena Guerrero Ceballos, Edith Mariela Burbano Rosero, E. Ibargüen-Mondragón","doi":"10.11144/JAVERIANA.SC25-3.COAR","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-3.COAR","url":null,"abstract":"Bacterial resistance to antibiotics is one of the largest medical concerns worldwide.One of the bacteria of critical priority is E. coli, since it presents different resistance mechanisms and some of its strains have evolved resistance to beta-lactam antibiotics. We characterized 32 antibiotic resistant bacterial isolates from confirmed cases of urinary tract infections from an array of patients in Nariño, southern Colombia. Macro and microscopic descriptions of the 32 clinical isolates were conducted. Resistance profiles, biochemical, and molecular characterization (via 16S rRNA gene sequencing, ERIC-PCR, and resistance genes) were performed. All the isolates were identified as E. coli and had resistance to beta-lactams, aminoglycosides, and fluoroquinolones. This resistance was related to plasmids carryingthebla TEM, blaSHV1, and blaCTXM1genes.There were significant differences between the resistance proportions of the samples (p value:0.0000), mainly to penicillin, cefotoxin, and imipenem. Using ERIC-PCR, four clonal states were evidenced that corroborate a degree of genetic differentiation with in the isolate set.Antibiotic resistance observed in the isolates is associated with resistance genes present in the bacterial chromosome and plasmids.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44803810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lactic acid bacteria (LAB) have an important role in the food industry because they are used in the production of fermented fo ds. To use these microorganisms in the food industry, it is necessary to obtain a high amount of biomass. One of the most important environmental factors in the growth of LAB is pH. Most of LAB species can tolerate a pH below 5.0, however, a suboptimal pH is expected to limit LAB growth. For this reason, the LAB strains Leuconostoc mesenteroides 67-1, Lactobacillus plantarum 60-1, and Streptococcus infantarius 46-3, isolated from sour cream, were grown in culture media under four different intial pH values to determine their optimal growth pH. Growth was assesed via colony-forming unit (CFU/ml) determination. We found that the growth of each LAB was affected by culture medium pH. We determined that the setpoints of pH for Leuconostoc mesenteroides 67-1, Streptococcus infantarius 46-3, and Lactobacillus plantarum 60-1 were of 4.5 (± 0.5), 5.5 (± 0.5), and 6.0 (± 0.5), respectively. We thus conclude that the growth of these LAB strains is pH-dependent (p < 0.05).
{"title":"Effect of pH on the growth of three lactic acid bacteria strains isolated from sour cream","authors":"Madalyd Yurani Vera-Peña, Wendy Lizeth Rodriguez-Rodriguez","doi":"10.11144/JAVERIANA.SC25-2.EOPO","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-2.EOPO","url":null,"abstract":"Lactic acid bacteria (LAB) have an important role in the food industry because they are used in the production of fermented fo ds. To use these microorganisms in the food industry, it is necessary to obtain a high amount of biomass. One of the most important environmental factors in the growth of LAB is pH. Most of LAB species can tolerate a pH below 5.0, however, a suboptimal pH is expected to limit LAB growth. For this reason, the LAB strains Leuconostoc mesenteroides 67-1, Lactobacillus plantarum 60-1, and Streptococcus infantarius 46-3, isolated from sour cream, were grown in culture media under four different intial pH values to determine their optimal growth pH. Growth was assesed via colony-forming unit (CFU/ml) determination. We found that the growth of each LAB was affected by culture medium pH. We determined that the setpoints of pH for Leuconostoc mesenteroides 67-1, Streptococcus infantarius 46-3, and Lactobacillus plantarum 60-1 were of 4.5 (± 0.5), 5.5 (± 0.5), and 6.0 (± 0.5), respectively. We thus conclude that the growth of these LAB strains is pH-dependent (p < 0.05).","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47118564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-27DOI: 10.11144/JAVERIANA.SC25-3.PODC
B. Jena, S. K. Paikray
In the present work, we introduce and study the notion of statistical probability convergence for sequences of random variables as well as the idea of statistical convergence for sequences of real numbers, which are defined over a Banach space via the product of deferred Cesàro and deferred weighted summability means. We first establish a theorem presenting aconnection between them. Based upon our proposed methods, we then prove a Korovkin-type approximation theorem with algebraic test functions for a sequence of random variables on a Banach space, and demonstrate that our theorem effectively extends and improves most (if not all) of the previously existing results (in classical as well as in statistical versions). Furthermore, an illustrative example is presented here by means of the generalized Meyer–König and Zeller operators of a sequence of random variables in order to demonstrate that our established theorem is stronger than its traditional and statistical versions. Finally, we estimate the rate of the product of deferred Cesàro and deferred weighted statistical probability convergence, and accordingly establish a new result.
{"title":"Product of deferred Cesàro and deferred weighted statistical probability convergence and its applications to Korovkin-type theorems","authors":"B. Jena, S. K. Paikray","doi":"10.11144/JAVERIANA.SC25-3.PODC","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-3.PODC","url":null,"abstract":"In the present work, we introduce and study the notion of statistical probability convergence for sequences of random variables as well as the idea of statistical convergence for sequences of real numbers, which are defined over a Banach space via the product of deferred Cesàro and deferred weighted summability means. We first establish a theorem presenting aconnection between them. Based upon our proposed methods, we then prove a Korovkin-type approximation theorem with algebraic test functions for a sequence of random variables on a Banach space, and demonstrate that our theorem effectively extends and improves most (if not all) of the previously existing results (in classical as well as in statistical versions). Furthermore, an illustrative example is presented here by means of the generalized Meyer–König and Zeller operators of a sequence of random variables in order to demonstrate that our established theorem is stronger than its traditional and statistical versions. Finally, we estimate the rate of the product of deferred Cesàro and deferred weighted statistical probability convergence, and accordingly establish a new result.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48520130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-02DOI: 10.11144/JAVERIANA.SC25-2.GBCB
Johanna Santamaría-Vanegas, L. C. Rodríguez-Rey
The neotropical otter (Lontra longicaudis) is considered a flagship species for the conservation of the ecosystems in which it resides and is currently in a vulnerable state. As a conservation strategy for this species, rehabilitation, breeding, and reintroduction programs of captive individuals have been proposed. However, it is likely that the environment and feeding conditions in captivity result in gut microbial communities that differ from those in wild animals. Gut microbial communities have an important role in the physiological performance of an animal. To determine differences between gut microbial communities of otters in wild and captive living conditions, the structure and diversity of their gut bacterial communities were determined using 16S rDNA molecular markers. Total DNA was isolated from fecal samples of wild animals from the La Vieja River basin and from captive animals in the Cali Zoo. As expected, the gut bacterial communities of captive animals converged to a more similar structure, and their bacterial diversity was significantly lower than that found in wild animals.
{"title":"Gut bacteria comparison between wild and captive neotropical otters","authors":"Johanna Santamaría-Vanegas, L. C. Rodríguez-Rey","doi":"10.11144/JAVERIANA.SC25-2.GBCB","DOIUrl":"https://doi.org/10.11144/JAVERIANA.SC25-2.GBCB","url":null,"abstract":"The neotropical otter (Lontra longicaudis) is considered a flagship species for the conservation of the ecosystems in which it resides and is currently in a vulnerable state. As a conservation strategy for this species, rehabilitation, breeding, and reintroduction programs of captive individuals have been proposed. However, it is likely that the environment and feeding conditions in captivity result in gut microbial communities that differ from those in wild animals. Gut microbial communities have an important role in the physiological performance of an animal. To determine differences between gut microbial communities of otters in wild and captive living conditions, the structure and diversity of their gut bacterial communities were determined using 16S rDNA molecular markers. Total DNA was isolated from fecal samples of wild animals from the La Vieja River basin and from captive animals in the Cali Zoo. As expected, the gut bacterial communities of captive animals converged to a more similar structure, and their bacterial diversity was significantly lower than that found in wild animals.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47049103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-28DOI: 10.11144/javeriana.sc25-2.bair
J. Lozada-Castro, David Arturo-Perdomo, Angie Pardo-Rueda
Biogenic amines (BAs) are low molecular weight nitrogenous compounds, formed by the breakdown of proteins in highly perishable food products such as fish. BAs can affect human health and are associated with cases of food poisoning. The formation of Bas such as histamine, putrescine, and tyramine were determined, via Process Analytical Chemistry (PAC), in three species of freshwater fish available in markets of city of Pasto in southern Colombia: rainbow trout, tilapia, and cachama. We evaluated the formation of BAs during the fish conservation processes and considered a multifactorial design with two levels. The factors studied were: fish species, slaughter type, storage temperature, and time to purchase. Out of the three fish species studies, tilapia samples revealed the highest average content of putrescine and histamine, with values of 5.4 µg/g and 10.04 µg/g, respectively. Tyramine was not detected in any of the experiments performed. The observed values of BAs in the samples analyzed were below locally tolerated maximal values and the European standard (200 µg/g). However, their presence reveals that factors such as sample storage temperature and time to consumption triggered their formation.
{"title":"Biogenic amines in rainbow trout, tilapia, and cachama fish, available for consumption in Nariño, southern Colombia","authors":"J. Lozada-Castro, David Arturo-Perdomo, Angie Pardo-Rueda","doi":"10.11144/javeriana.sc25-2.bair","DOIUrl":"https://doi.org/10.11144/javeriana.sc25-2.bair","url":null,"abstract":"Biogenic amines (BAs) are low molecular weight nitrogenous compounds, formed by the breakdown of proteins in highly perishable food products such as fish. BAs can affect human health and are associated with cases of food poisoning. The formation of Bas such as histamine, putrescine, and tyramine were determined, via Process Analytical Chemistry (PAC), in three species of freshwater fish available in markets of city of Pasto in southern Colombia: rainbow trout, tilapia, and cachama. We evaluated the formation of BAs during the fish conservation processes and considered a multifactorial design with two levels. The factors studied were: fish species, slaughter type, storage temperature, and time to purchase. Out of the three fish species studies, tilapia samples revealed the highest average content of putrescine and histamine, with values of 5.4 µg/g and 10.04 µg/g, respectively. Tyramine was not detected in any of the experiments performed. The observed values of BAs in the samples analyzed were below locally tolerated maximal values and the European standard (200 µg/g). However, their presence reveals that factors such as sample storage temperature and time to consumption triggered their formation.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48256389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-16DOI: 10.11144/javeriana.sc25-2.csas
J. Gómez-Cuaspud, A. Y. Neira-Guio, E. Vera-López, Luís C. Canaría-Camargo
Lithium cobalt oxide (LiCoO2) is one of the most relevant components in lithium-ion batteries. The array of sought-after features of LiCoO2 depends on its synthesis method. In this work we synthesized and characterized a nanocrystalline LiCoO2 oxide obtained with a wet chemistry synthesis method. The oxide obtained was a homogeneous powder in the nanometric range (5-8 nm) and exhibited a series of improved properties. Characterization by FTIR and UV-Vis techniques led to identifying citrate species as main products in the first step of the synthesis process. X-ray diffraction (XRD), Raman, and transmission electron microscopy (TEM) characterizations led to identifying a pure crystalline phase of the synthesized LiCoO2 oxide. Steady state electrical characterization and solid-state impedance spectroscopy determined the high conductance of the synthesized oxide. All these features are desirable in the design of cathodes for lithium ion batteries.
{"title":"Chemical synthesis and steady state characterization of a nanocrystalline lithium cobalt oxide","authors":"J. Gómez-Cuaspud, A. Y. Neira-Guio, E. Vera-López, Luís C. Canaría-Camargo","doi":"10.11144/javeriana.sc25-2.csas","DOIUrl":"https://doi.org/10.11144/javeriana.sc25-2.csas","url":null,"abstract":"Lithium cobalt oxide (LiCoO2) is one of the most relevant components in lithium-ion batteries. The array of sought-after features of LiCoO2 depends on its synthesis method. In this work we synthesized and characterized a nanocrystalline LiCoO2 oxide obtained with a wet chemistry synthesis method. The oxide obtained was a homogeneous powder in the nanometric range (5-8 nm) and exhibited a series of improved properties. Characterization by FTIR and UV-Vis techniques led to identifying citrate species as main products in the first step of the synthesis process. X-ray diffraction (XRD), Raman, and transmission electron microscopy (TEM) characterizations led to identifying a pure crystalline phase of the synthesized LiCoO2 oxide. Steady state electrical characterization and solid-state impedance spectroscopy determined the high conductance of the synthesized oxide. All these features are desirable in the design of cathodes for lithium ion batteries.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41785732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-06DOI: 10.11144/javeriana.sc24-3.eola
Ricardo Cano-Macias, Jorge Mauricio Ruiz-Vera
In this paper we prove the existence and uniqueness of weak solutions for a kind of Lotka–Volterra system, by using successive linearization techniques. This approach has the advantage to treat two equations separately in each iteration step. Under suitable initial conditions, we construct an invariant region to show the global existence in time of solutions for the system. By means of Sobolev embeddings and regularity results, we find estimates for predator and prey populations in adequate norms. In order to demonstrate the convergence properties of the introduced method, several numerical examples are given.
{"title":"Existence of local and global solution for a spatio-temporal predator-prey model","authors":"Ricardo Cano-Macias, Jorge Mauricio Ruiz-Vera","doi":"10.11144/javeriana.sc24-3.eola","DOIUrl":"https://doi.org/10.11144/javeriana.sc24-3.eola","url":null,"abstract":"In this paper we prove the existence and uniqueness of weak solutions for a kind of Lotka–Volterra system, by using successive linearization techniques. This approach has the advantage to treat two equations separately in each iteration step. Under suitable initial conditions, we construct an invariant region to show the global existence in time of solutions for the system. By means of Sobolev embeddings and regularity results, we find estimates for predator and prey populations in adequate norms. In order to demonstrate the convergence properties of the introduced method, several numerical examples are given.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46437048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-05DOI: 10.11144/javeriana.sc24-3.arcr
A. Salamanca, Luis Montes-Vides
The estimation of static corrections is an issue still unsolved for PS converted wave processing. Due to the PS converted wave usually arriving at the surface at non-zero angles, the surface consistent approach is no longer valid, and corrections become non-stationary, i.e. the correction is not static. Seismic interferometry is used in receiver gathers transformed to the radial domain to estimate functions that contain the delay caused by the weathered layer, considering the emergence angle of the PS converted wave. Inverse filters, derived from these functions, are applied by convolution to the raw traces to supply traces corrected for weathering layer effects. Seismic interferometry was satisfactorily tested in two synthetic models and then applied to a 2C seismic line from the Llanos Basin (Colombia). This is the first application of the technique in Colombia, initially developed for permafrost zones, with different assumptions and surface complexity; and it resulted in an improved PS converted wave image.
{"title":"A raypath-consistent receiver correction in PS converted wave processing through seismic interferometry: New application for tropical zones","authors":"A. Salamanca, Luis Montes-Vides","doi":"10.11144/javeriana.sc24-3.arcr","DOIUrl":"https://doi.org/10.11144/javeriana.sc24-3.arcr","url":null,"abstract":"The estimation of static corrections is an issue still unsolved for PS converted wave processing. Due to the PS converted wave usually arriving at the surface at non-zero angles, the surface consistent approach is no longer valid, and corrections become non-stationary, i.e. the correction is not static. Seismic interferometry is used in receiver gathers transformed to the radial domain to estimate functions that contain the delay caused by the weathered layer, considering the emergence angle of the PS converted wave. Inverse filters, derived from these functions, are applied by convolution to the raw traces to supply traces corrected for weathering layer effects. Seismic interferometry was satisfactorily tested in two synthetic models and then applied to a 2C seismic line from the Llanos Basin (Colombia). This is the first application of the technique in Colombia, initially developed for permafrost zones, with different assumptions and surface complexity; and it resulted in an improved PS converted wave image.","PeriodicalId":39200,"journal":{"name":"Universitas Scientiarum","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46388352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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