Morpho-Molecular Characterization of Ditylenchus dipsaci and Alternatives for Its Management in Green Onion Allium fistulosum Crops from Colombia

Green onion is one of the most consumed vegetables in Colombia. However, its production is negatively affected by the nematode Ditylenchus. To determine the species of the nematode, as well as to propose management strategies for its control, in the present study the morphological, morphometric, and molecular characterization of the phytonematode was carried out and was used to evaluate the effect of immersion of the propagation material in water hot, application of a commercial strain of Purpureocillium lilacinum and the application of an agrochemical with insecticidal-nematicidal action to control the phytosanitary problem under field conditions. The morphological and morphometric characteristics of the nematode were similar to those reported for the type and reference populations of D. dipsaci. Based on sequences of the D2-D3 segment and Internal Transcribed Spacer-ITS of the rRNA, the presence of D. dipsaci in green onion crops in Colombia was confirmed. The application of P. lilacinum statistically showed an efficient control of D. dipsaci, at the same time that presented the highest yield, in relation to the other evaluated treatments (P ≤ 0.05).

Sociodemographic determinants associated with breastfeeding in term infants with low birth weight in Latin American countries

BACKGROUND A progressive decrease in exclusive breastfeeding(BF)is observed in Latin America and the Caribbean compared with global results.The possibility of being breastfed and continuing BF for>6 months is lower in low birth weight than in healthy-weight infants.AIM To identify factors associated with BF maintenance and promotion,with particular attention to low-and middle-income countries,by studying geographic,socioeconomic,and individual or neonatal health factors.METHODS A scoping review was conducted in 2018 using the conceptual model of social determinants of health published by the Commission on Equity and Health Inequalities in the United States.The extracted data with common characteristics were synthesized and categorized into two main themes:(1)Sociodemographic factors and proximal determinants involved in the initiation and maintenance of BF in low-birth-weight term infants in Latin America;and(2)individual characteristics related to the self-efficacy capacity for BF maintenance and adherence in low-birth-weight term infants.RESULTS This study identified maternal age,educational level,maternal economic capacity,social stratum,exposure to BF substitutes,access to BF information,and quality of health services as mediators for maintaining BF.CONCLUSION Individual self-efficacy factors that enable BF adherence in at-risk populations should be analyzed for better health outcomes.

Gastric mucosa-associated lymphoid tissue lymphomas and Helicobacter pylori infection:A Colombian perspective

AIM:To assess the significance of chromosome translocation t(11;18)(q21;q21),B-cell lymphoma 10 (BCL-10) protein and Helicobacter pylori (H.pylori) infection in gastric mucosa-associated lymphoid tissue (MALT) lymphoma in Colombia.METHODS:Fifty cases of gastric MALT lymphoma and their respective post-treatment follow-up biopsies were examined to assess the presence of the translocation t(11;18)(q21;q21) as identified by fluorescence in situ hybridization;to detect protein expression patterns of BCL10 using immunohistochemistry;and for evaluation of tumor histology to determine the correlation of these factors and resistance to H.pylori eradication.RESULTS:Infection with H.pylori was confirmed in all cases of gastric MALT lymphoma in association with chronic gastritis.Bacterial eradication led to tumor regression in 66% of cases.The translocation t(11;18)(q21;q21) was not present in any of these cases,nor was there evidence of tumor transformation to diffuse large B-cell lymphoma.Thirty-four percent of the patients showed resistance to tumor regression,and within this group,7 cases,representing 14% of all those analyzed,were considered to be t(11;18)(q21;q21)-positive gastric MALT lymphomas.Protein expression of BCL10 in the nucleus was associated with the presence of translocation and treatment resistance.Cases that were considered unresponsive to therapy were histologically characterized by the presence of homogeneous tumor cells and a lack of plasmacytic differentiation.Responder cases exhibited higher cellular heterogeneity and a greater frequency of plasma cells.CONCLUSION:Both t(11;18)(q21;q21)-positive MALT lymphoma cases and those with nuclear BCL10 expression are considered resistant to H.pylori eradication.It is suggested that chronic antigenic stimulation is not a dominant event in resistant cases.

Behavior of diatomaceous soil in lacustrine deposits of Bogota, Colombia

This work presents a study on the behaviors of diatomaceous soils. Although studies are rarely reported on these soils, they have been identified in Mexico City, the Sea of Japan, the northeast coast of Australia,the equatorial Pacific, and the lacustrine deposit of Bogota(Colombia), among other locations. Features of this kind of soil include high friction angle, high initial void ratio, high compressibility index, high liquid limit, and low density. Some of these features are counterintuitive from a classical soil mechanics viewpoint. To understand the geotechnical properties of the diatomaceous soil, a comprehensive experimental plan consisting of more than 2400 tests was performed, including physical tests such as grain size distribution, Atterberg limits, density of solid particles, and organic matter content; and mechanical tests such as oedometric compression tests, unconfined compression tests, and triaxial tests.Laboratory tests were complemented with scanning electron microscope(SEM) observations to evaluate the microstructure of the soil. The test results show that there is an increase in liquid limit with increasing diatomaceous content, and the friction angle also increases with increasing diatomaceous content. In addition, several practical correlations were proposed for this soil type for shear strength mobilization and intrinsic compression line. Finally, useful correlations were presented, such as the relationship between the state consistency and the undrained shear strength, the friction angle and the liquid limit, the void ratio at 100 kPa and the liquid limit, the plasticity index and the diatomaceous content, among others.

Site index for teak in Colombia

Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations. Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and clas- sify site quality ofteak （Tectona grandis） plantations by using data from 44 permanent sample plots established since 1990 in 3--22 years old teak plantations in the Colombian Caribbean region. We used Korf＇s and yon Bertalanffy＇s models to fit curves as non-linear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf＇s model was superior. The resulting curves were anamorphic and closely reflected high variability in site quality. Five site classes were clarified： at a base age of 12 years old, teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m in the worst sites, and in the averages sites, 15.8-18.8 m. Using this model, we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.

The importance of grain and cut-off size in shaping tree beta diversity along an elevational gradient in the northwest of Colombia

Background:Species turnover(β-diversity)along elevational gradients is one of the most important concepts in plant ecology.However,there is a lack of consensus about the main driving mechanisms of treeβ-diversity at local scales in very diverse ecosystems(e.g.,Andean mountains),as well as how the sampling effect can alterβ-diversity estimations.Recently,it has been hypothesized that patterns of change inβ-diversity at local scales along elevational gradients are driven by sampling effects stemming from differences in the size of the species pool rather than by underlying community assembly mechanisms.Thus,we aim to evaluate the relative extent to which sampling effects,such as species pool size,grain size,and tree size cut-off,determine species sorting,and thus,the variability ofβ-diversity at local scales along elevational gradients in the northwest of Colombia.Results:Using 151-ha permanent plots spread out along a 3000m elevational gradient,we used standardizedβ-deviation to assess the extent to which either sampling effects or the community assembly mechanisms determine the changes in species composition at local scales.Standardizedβ-deviation was measured as the difference between the observed and nullβ-diversity divided by the standard deviation of the nullβ-diversity.We found that the magnitude of change in localβ-deviation along the elevational gradient was significant and dependent on the employed spatial grain size and tree size cut-off.However,β-deviation increased with elevation in all sampling designs,which suggests that underlying community assembly mechanisms play a key role in shaping localβ-diversity along the elevational gradient.Conclusions:Our findings suggest that grain size enlargement and the inclusion of trees with small diameters will improve our ability to quantify the extent to which the community assembly mechanisms shape patterns ofβ-diversity along elevational gradients.Overall,we emphasize the scale-dependent nature of the assessment ofβ-diversity.Likewise,we call for the need of a new generation of enlarged forest inventory plots along gradients of elevation in tropical forests that include small individuals to improve our understanding about the likely response of diversity and function to global change.

First isolation and identification of H1N1 swine influenza viruses in Colombian pig farms

The pig industry in Colombia has grown 30% in the last decade achieving high levels of technology and efficiency;in spite of that, respiratory diseases remain a constraint. Since 1970, serological evidence and histological findings suggested the role of swine influenza virus (SIV) as part of the porcine respiratory disease complex;nevertheless, elusive and molecular typing isolates are missing. This study was aimed at isolating SIV from intensive pig farms and to achieve molecular characterization to determine strains circulating in the field. In order to accomplish this goal, 242 samples were taken from nasal swabs, 25 from bronchial washes and 8 from lung tissue. Samples were collected during a period of three years, between 2008 and 2010 and were originated from 78 farms of the three main pig production regions of the country. The samples were transported in BHI broth with 2% antibiotic and antimycotic solution and stored at –70?C until processed. The swabs were inoculated in 9 - 11 days old embryo chicken eggs and in MDCK (Madin Darby Canine Kidney) cell cultures with the addition of trypsin. The isolates were identified by the HA (hemoagglutination) test and by RT-PCR targeting the HA (hemagglutinin), NA (Neuraminidase) and M (Matrix) genes. Full length sequence of the HA and NA glycoproteins from four selected virus isolates was conducted (Macrogen?. USA). As a result, fifteen SIV isolates from nine farms distributed in the three regions were obtained. Twelve of the isolates are related to the swine origin H1N1 virus that caused the 2009 influenza pandemic. The remaining three viruses were related to classical swine influenza viruses.

Establishing geothermometric constraints on the local geothermal gradients:Case study of the Eastern Cordillera Basin,Colombia

Geochemical analyses were performed on 170 coal bed-trapped groundwater samples from 97 underground mines located in the Eastern Cordillera Basin, Colombia. The waters analyzed in this paper are from exploited coal beds, located up to 0.73 km deep, which emerge along with the local fault systems.The hydrochemical facies were classified based on the concentration of major ions by inferring the equilibrium state and rock water source. The main hydrochemical facies presented in the groundwater study are SO_4-Ca-Mg, HCO_3-Ca, HCO_3-Ca-Mg, and SO_4-HCO_3 mixed waters. We used geothermometric equations to estimate the most probable temperature under in-situ conditions and the propagation of errors theory to test the results. The geothermal gradient in the study area is close to 30℃/km, which is consistent with measurements from oil wells within the study area. Principal Component Analysis was used to explain factors affecting formation water composition and hydrogeochemical evolution of aquifers.

Some contributions to mechanical behaviors of lacustrine deposit in Bogota, Colombia

This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size distribution,scanning electron microscopy,Atterberg limits and water content).This characterization intends to explain the special characteristics of the mechanical behaviors of this soil.Then,various triaxial tests are carried out with controlled loading path,strain rate change,relaxation,extensile stress,and cyclic loading.The test results reveal the shape of the yield curve for Bogotá soil (in a natural state),and also show that an increasing effect of the strain rate depends on the liquid limit.This effect is also preserved with extensile stresses (which are poorly studied in soil mechanics).Finally,other effects,such as the loss of structure in the reconstituted samples and the effect of shear modulus at low strains,are studied for Bogota soil.

Earthquake distribution and lithospheric rheology beneath the Northwestern Andes, Colombia

The rheological behavior of the lithosphere beneath the Northwestern(NW)Andes(Colombian)remains uncertain under a complex geological setting.Here,we analyze the earthquake distribution and the stress drop on the western and the eastern of the transition area between the Upper Magdalena Valley(UMV)and the Middle Magdalena Valley(MMV),a zone related to a plate tectonic transition from steeper to flatter subduction style slabs(Nazca and Caribbean plates).Our results consistently explain the tectonic and geodynamic context of the study area supported in two rheological profiles,which reveal the brittle/ductile transition of the lithospheric crust and mantle and allow to constrain the lithospheric rheological thickness.The subduction phenomenon of the Nazca Plate under the South American Plate is observed in the western zone.In the eastern region,we find a remarkable aseismic zone under the Eastern Cordillera below 20-km-deep,which made more difficultan accurate estimation of the crust/mantle boundary.This seismic particularity leads us to support the hypothesis of a delamination process due to the tectonic overload generated by the Eastern Cordillera,and that promotes thermal anomalies.Our results also suggest that the earthquake dataset correlated with rheological estimations may offer a consistent interpretation of the mechanical behavior of the lithosphere.

Modeling height growth for teak plantations in Colombia using the reducible stochastic differential equation approach

Teak(Tectona grandis L.f.)plantations are increasingly being established in tropical regions to meet a rising demand for its highly valued timber.Teak plantations have been established in the Atlantic Coastal Plain region of Colombia,a region climatically suitable for teak growth by having a monsoon climate with a unimodal precipitation pattern.Tree diameter at breast height(DBH,1.3 m above ground)and mean top height,periodically measured over a 17-year period in 44 permanent sampling plots of size 0.06 and 0.10 ha,were used in this study.A stochastic differential equation(SDE),along with a Bertalanffy–Richards-type height growth model,was used to model and estimate top height growth of teak plantations in Colombia.Environmental noise and height measurement errors were explicitly considered as the main uncertainty sources of mean top height growth.The best model for estimating mean top height,based on statistical performance and biological rationale,had the asymptote defined as a local parameter and the growth rate and shape specified as global parameters.This model outperformed its counterpart that had the growth rate specified as a local parameter and asymptote and shape as global parameters.The selected model also outperformed alternative approaches such as the mixed-effects model,generalized algebraic difference approach,and the dummy variable method.Estimated trajectories for the mean top height of teak in Colombia are biologically sound based on the measured height series and previous studies in Latin America.Results suggest that most of the uncertainty associated with the mean top height growth of teak plantations in Colombia was largely explained by environmental noise.The best estimated model using the SDE approach can be useful for predicting height growth and evaluating site productivity of teak plantations in Colombia and in neighbouring countries with biophysical characteristics similar to those where teak has been planted in Colombia.

The Influence of Climate Variability on Holoplanktonic Polychaetes Populations of Ocean Sector of the Colombian Pacific Basin

Studies of holoplanktonic polychaetes in the Tropical Eastern Pacific have focused on their systematics and distribution however, population responses related to climate variability are non-existent. Therefore, the present work described for the first time the influence of the climatic variability 2004-2012 on the holoplanktonic polychaetes populations, as well as their relationship to environmental variables. Species of the Alciopidae, Lopadorrhynchidae and Iospilidae families were identified from 85 samples collected in the Pacific Basin of Colombia, contrasting them with the presence of ENSO, and correlating them with the environmental variables of temperature, salinity and chlorophyll-α concentration. Of the 14 species identified, only Lopadorrhynchus cf. henseni and L. cf. brevis increased their densities under El Niño and correlated positively with temperature. Rhynchonereella cf. petersii correlated negatively with temperature;while R. cf. gracilis and Pelagobia cf. longicirrata were positively correlated with chlorophyll-α concentration and salinity, respectively. Additionally, with the first description of the environmental ranges of the 14 species identified for the Colombian Pacific basin, it was found that the most commons species presented broader environmental ranges. The results from the current research are consistent with previous studies in other regions of the Pacific and latitudes. The responses of the organisms suggest trophic and mobility trends that were not known for tropical holoplanktonic polychaete species.

Using Biophysical Variables and Stand Density to Estimate Growth and Yield of <i>Pinus patula</i>in Antioquia, Colombia

Timberland investment opportunities in Colombia are expected to increase as a result of the peace agreement recently signed between the Colombian government and the Revolutionary Armed Forces of Colombia. This new socio-political environment may facilitate the expansion of commercial forest plantations on a wider range of site conditions that are currently considered in existing biometric tools. Data from 1119 temporary plots of unthinned, unmanaged, and genetically unimproved Pinus patula plantations in the Antioquia region were combined with a large set of biophysical attributes to identify spatial variation in yield. A wide array of biophysical covariates was explored to characterize the most favorable environmental conditions for the species, and to identify potential explanatory variables to be included in forest yield models. The mathematical form of the model is the von Bertalanffy-Chapman-Richards type, with parameters: asymptote, intrinsic growth rate and allometric constant. The parameters were expressed as linear functions of soil pH, terrain slope, the mean annual temperature to mean annual precipitation ratio, and stand density. The statistical contribution of selected covariates was evaluated using the likelihood ratio test. The model was validated using an independent set of 133 observations. The spatial representation of the model depicts the timber production potential and allows for the identification of the most suitable geographical areas to establish Pinus patula plantations in Antioquia, Colombia. The estimated yield model provides a reliable baseline for timber production, and insight into timberland investments in Colombia.

Incidence evaluation of <i>Crypticerya multicicatrices</i>and <i>Maconellicoccus hirsutus</i>in Colombian Seaflower Biosphere Reserve

An evaluation of the incidence of Crypticerya multicicatrices and Maconellicoccus hirsutus in Colombian Seaflower Biosphere Reserve in San Andrés, Providence and Santa Catalina islands, from mid-August to mid-November 2012 was made. 38 locations were sampled, and 34% of sites tested show an incidence of C. multicicatrices oscillating between a range of 80%-100%, 24% with 40%-80% of incidence, 18% between 10%-40% and 24% with a range of 0%-10%. The occurrence of M. hirsutus fluctuated between 0.5% and 17%. There were seven genera of ants associated C. multicicatrices and 94 hosts of this agriculturally important insect and we found high incidence of associated sooty mold in C. multicicatrices hosts. Observations also contained some developmental stages of C. multicatrices.

Variation in abundance and habitat relationship of three understory insectivorous birds in a disturbed landscape of Neotropical dry forest of Colombia

Background:Evaluating relationships between avian populations and their habitat is important for understanding the biology of these species and for management decisions that improve the effectiveness of restoration practices.We investigated how habitat variation along a disturbance gradient affected the abundance of three insectivorous bird species,White-bellied Antbird(Myrmeciza longipes),Barred Antshrike(Thamnophilus doliatus),and Pale-breasted Spinetail(Synallaxis albescens)in a Neotropical dry forest remnant in central Colombia.Methods:The study area,which is located in Magdalena Valley,is under ecological restoration after the construction of the“El Quimbo”hydroelectric dam,with a gradient of habitat conditions,from relatively advanced secondary growth to recently disturbed areas.We conducted bird surveys and quantified the habitat conditions from June 2018 to June 2019.We compared the relative abundance of the birds among the three zones with increasing disturbance and modeled the relationship between the bird abundance with the micro-and landscape-habitat conditions,with Poisson generalized linear model regression.Results:The relative abundance of the three bird species varied according to the habitat features and disturbance level.The abundance of White-bellied Antbirds was higher in forests and thickets than shrubland fragments;Barred Antshrike was more abundant in shrubland and thickets than in forest fragments,and Pale-breasted Spinetail had the highest abundance in shrubland and the lowest in forest fragments.The abundance of both White-bellied Antbird and Pale-breasted Spinetail did not differ among zones with different levels of disturbance,while the abundance of Barred Antshrike decreased in zones with more disturbance.Conclusions:There were significant differences in the habitat relationships of the three understory insectivorous species along the disturbance gradient,although these species were within the same trophic group.These bird species preferred different stages of habitat succession and responded to different habitat and landscape features.Increasing forest fragment areas and decreasing the amount of edge would be useful restoration priorities for these and other similar avian species in this study area.

Geological inferences about the upper crustal configuration of the Medellin-Aburra Valley(Colombia)using strong motion seismic records

In regions of complex geology and tectonic assembly, strong motion seismic arrival time records can be used to test the plausibility of existing hypothesis about the origin of lithological and tectonic features and how they are related in space and time. In this study we use differential travel time residuals at some strong motion accelerographic stations in the Medellin-Aburra Valley, in the northern Central Cordillera of the Colombian Andes, to discuss some aspects of the geological configuration. We based our work on the hypothesis that the differences between seismic travel time residuals among pairs of stations are a function of the differences in the surface geology and the near-surface upper crustal configuration. Our results are consistent with the volcanic rocks of the Quebradagrande Complex being less mafic, more weathered or more tectonically affected than previously thought, with the presence of a relatively thin dunite body on top of the metamorphic basement, and with a large lateral heterogeneity in the mainly mafic San Diego Stock.

Potyvirus Affecting Uchuva(Physalis peruviana L.)in Centro Agropecuario Marengo,Colombia

Fruit production and especially fresh tropical fruit trade, has an important relevance on world economy. Refining knowledge on virus diseases affecting tropical fruits is required to improve the understanding of these diseases, their dynamics and consequently, the ability to manage them. In this paper, samples of “uchuva” plants (Physalis peruviana L.) obtained from Centro Agropecuario Marengo (CAM) Municipality of Mosquera, Cundinamarca region of Colombia were analyzed after expressing symptoms of leaf chlorosis, leaf malformation, mosaic patterns and dwarfing. Electron microscopy revealed the presence of two different viral particles congruent with Potyvirus and Tobamovirus genus morphology. The presence of Potyvirus affecting the P. peruviana L. culture was confirmed in the samples analyzed by means of electronic microscopy images and serology. Similarly, the existence of viral particles with coherent characteristics of a putative Tobamovirus was observed. However, its presence could not be confirmed by means of serological tests. Nevertheless, its incidence should not be neglected. The mechanism of Potyvirus disease transmission in P. peruviana L. remains unknown, as well as the vectors associated with this disease. Therefore, complementary work and research should be considered. In addition to serology and electron microscopy, the use of indicator plants for diagnosis is suggested. Finally, a complete molecular characterization of the Potyvirus is recommended for a better understanding of the characteristics of its association with P. peruviana L.

Lonicera caerulea polyphenols inhibit fat absorption by regulating Nrf2-ARE pathway mediated epithelial barrier dysfunction and special microbiota

Scope:High-fat diet(HFD)induces imbalance in the small intestine environment,where fat digestion and absorption mainly take place.This study aimed to elucidate the mechanisms by which Lonicera caerulea polyphenols(LCP)might inhibit fat absorption,from the perspective of small intestine microbiota and epithelial barrier integrity.Methods and results:Male Sprague-Dawley rats were given HFD with or without co-administration of LCP for 8 weeks.The results showed that LCP supplementation significantly decreased the levels of serum triglycerides(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C),and increased the contents of fecal sterols,in HFD rats.LCP also inhibited the dysfunction of the small intestine epithelial barrier,via alleviating the oxidative stress activated by Nrf2-ARE pathway,and by modulating the expressions of pro-inflammatory factors such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),cyclooxygenase-2(COX-2),nuclear factor kappa-B p65(NF-κB p65)and inducible nitric oxide synthase(iNOS)in the small intestine.Additionally,LCP administration restored the balance in small intestine microbiota and increased the abundance of the specific bacteria,such as Lactobacillus,involved in fat absorption.Conclusion:Our results demonstrated that LCP may be beneficial to inhibit fat absorption.The mechanism seems to be associated with the protection of the epithelial barrier integrity and the modulation of specific bacteria in the small intestine.

Auditory function in symptomatic patients recovered from SARS-CoV-2 and unexposed patients:An analytical cross-sectional study

Objective:To describe audiological symptoms,audiometric profile,and distortion product otoacoustic emission in symptomatic patients recovering from SARS-CoV-2 infection(positive RT-PCR test)and asymptomatic patients(negative RT-PCR test).Methods:An analytical cross-sectional study was conducted using data obtained from clinical charts,physical examination,audiometry,and distortion product otoacoustic emission on 40 patients[case patients(CP)]recovering from SARS-CoV-2 infection diagnosed by a positive RT-PCR test and 22asymptomatic participants with a negative RT-PCR test[non-case(NC)].Results:Sixty-two patients(mean age:31.1 and 28.2 years in the CP and NC groups,respectively)were included.All participants were young without significant comorbidities,risk factors for hearing loss or otological history.Vertigo(5%),tinnitus(17.5%)and aural fullness/hearing loss(35%)were found in the CP group.A statistically significant difference was found in specific frequencies(1000,4000,and 8000 Hz)and pure tone average(low and high conversational frequencies with increased threshold in the PC group compared with the NC group),which was not found in distortion product otoacoustic emission.Conclusion:Audiovestibular symptoms are frequent in symptomatic patients recovering from SARS-CoV-2 infection.SARS-CoV-2 infection was consistently associated with an increased audiometric hearing threshold at specific frequencies and low tone average.