Universitas Scientiarum

<font color="#000080">Universitas Scientiarum (Univ. Sci.) is registered at the ISSN National Centre (ISSN 0122-7483 printed version, ISSN 2027-1352 online version) and indexed in Scopus, Chemical Abstracts (CA), SciELO, Google scholar, ULRICHS-WEB, Latindex, Periódica, Redalyc, Indice Bibliográfico Nacional (Publindex), and Directory of Open Access Journals (DOAJ). Universitas Scientiarum is a refereed scientific journal and is edited at the Faculty of Sciences of the Pontificia Universidad Javeriana (Bogotá, Colombia) and has been published continuously since 1987. Universitas Scientiarum publishes original papers, reviews, brief communications, editorials, letters to the Editor, and reviews of books, handbooks and meetings. The journal receives manuscripts in Spanish, Portuguese or English. The journal will accept papers on any subject of natural, physical or exact sciences.<br></font><br>

List of Papers (Total 482)

Between Open Sets and Semi-Open Sets

We introduce and investigate ω s-open sets as a new class of sets which lies strictly between open sets and semi-open sets. Then we use ω s-open sets to introduce ω s-continuous functions as a new class of functions between continuous functions and semi-continuous functions. We give several results and examples regarding our new concepts. In particular, we obtain some...

Rollinia mucosa (Jacq.) Baillon (Annonaceae) active metabolites as alternative biocontrol agents against the lace bug Corythucha gossypii (Fabricius): an insect pest

The lace bug, Corythucha gossypii (Fabricius) is a serious pest affecting over 24 wild and commercially important plant species of the families Annonaceae, Passiflorcae, Caricaceae, Euphorbiaceae, and Solanaceae. Thus far, commercial insecticides, such as 0.1% Dimethoate and 0.1% Imidacloprid have shown effectiveness against this insect, but no botanical pesticides are available...

Morphometric relationships and size at sexual maturity of the deep-sea Caribbean lobster Metanephrops binghami (Decapoda: Nephropidae) in the Colombian Caribbean

This paper describes the morphometric relationships and size at sexual maturity of deep-sea Caribbean lobster. Data were obtained in the Colombian Caribbean in four trawling surveys in November and December 2009 between 200 and 550 m depth. 709 individuals with sizes between 53.65 and 191.00 mm (TL) (mean 121.17 ± 27.13 mm) were measured. M. binghami had a positive allometric...

Variations in β(T)-function due to addition of LiI-4AgI system

Impedance spectroscopy measurements of the LiI-4AgI samples, in the frequency range 20 Hz{1 MHz, and in the temperature range between 353 K and 378 K were made. Both pure and lithium-doped silver iodide showed blocking phenomena in the electrodes and the grain boundary. The blocking phenomena allowed a change in the transport properties of the pure compound in respect to the...

Response Surface Methodology (RSM) for analysing culture conditions of Acidocella facilis strain USBA-GBX-505 and Partial Purification and Biochemical Characterization of Lipase 505 LIP

Using Response Surface Methodology (RSM) we evaluated the culture conditions (nitrogen source, carbon source, pH and agitation rate) that increase the biomass of Acidocella facilis strain USBA-GBX-505 and therefore enhance the production of its lipolytic enzyme, 505 LIP. RSM results revealed that yeast extract and agitation were key culture factors that increased the growth...

Asymptotic Approximations to the Isothermal Pyrolysis of Deodara Leaves using Gamma Distribution

The main aim of this paper pivoted around the influence of some parameters relevant to biomass pyrolysis on the numerical solutions of the nth order distributed activation energy model (DAEM) using the Gamma distribution. The upper limit of ‘dE’ integral, frequency factor, reaction order, and the shape and rate parameters of the Gamma distribution are investigated. Analysis of...

Efficiency of Pollution Tolerance Index (PTI) of macroinvertebrates in detecting aquatic pollution in an oxbow lake in India

This paper evaluates the efficiency of a macroinvertebrate-based Pollution Tolerance Index (PTI) in detecting aquatic pollution in the Chhariganga oxbow lake in India. In this lake, calculated PTIs were compared with results from an array of physicochemical water and sediment parameters and to a macroinvertebrate diversity assessment conducted in parallel for the same lake. The...

High temperature CO 2 capture of hydroxyapatite extracted from tilapia scales

Hydroxyapatite (HAp) was obtained from tilapia scales by two extraction methods: direct calcination and acid-base treatment. The physicochemical characteristics of the obtained HAps were evaluated by thermogravimetric analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, surface area, infrared spectroscopy, and basicity measurement at 298 K by CO2 -pulse...

Study of the fluorescence quenching of 1-hydroxypyrene-3,6,8-trisulfonic acid by single-walled carbon nanotubes

This paper presents a study of the fluorescence quenching of 1-hydroxypyrene-3,6,8-trisulfonic acid (HPTS) in the presence of single-walled carbon nanotubes (SWCNT) using a fluorescence method. To investigate the quenching mechanism (dynamic or static) of HPTS, Stern-Volmer plots of single walled carbon nanotubes at different temperatures were used. The positive deviation from...

Environmental and zooplankton parameter changes during the drying of a saline shallow temporary lake in central Argentina

Central Argentina has numerous saline lakes sustained by groundwater sources and rainfall. These lakes are temporary and experience significant changes in water level and salinity, depending on wet and dry climate cycles. This study aims to investigate the scarcely known dynamics of environmental and zooplankton parameters during the drying phase of one of these lakes. Monthly...

High temperature CO 2 capture of hydroxyapatite extracted from tilapia scales

Hydroxyapatite (HAp) was obtained from tilapia scales by two extraction methods: direct calcination and acid-base treatment. The physicochemical characteristics of the obtained HAps were evaluated by thermogravimetric analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, surface area, infrared spectroscopy, and basicity measurement at 298 K by CO2 -pulse...

Environmental and zooplankton parameter changes during the drying of a saline shallow temporary lake in central Argentina

Central Argentina has numerous saline lakes sustained by groundwater sources and rainfall. These lakes are temporary and experience significant changes in water level and salinity, depending on wet and dry climate cycles. This study aims to investigate the scarcely known dynamics of environmental and zooplankton parameters during the drying phase of one of these lakes. Monthly...

Morphometric relationships and size at sexual maturity of the deep-sea Caribbean lobster Metanephrops binghami (Decapoda: Nephropidae) in the Colombian Caribbean

This paper describes the morphometric relationships and size at sexual maturity of deep-sea Caribbean lobster. Data were obtained in the Colombian Caribbean in four trawling surveys in November and December 2009 between 200 and 550 m depth. 709 individuals with sizes between 53.65 and 191.00 mm (TL) (mean 121.17 ± 27.13 mm) were measured. M. binghami had a positive allometric...

Study of body fluid samples using flow cytometry: Six years of experience at the Hospital Universitario San Ignacio - Pontificia Universidad Javeriana, Bogota - Colombia

Flow cytometry (FCM) was implemented in 2008 at the Pontificia Universidad Javeriana and later at the Hospital Universitario San Ignacio to examine special samples of patients with hematological malignancies and solid tumors other than bone marrow and peripheral blood for diagnosis and monitoring. This study describes the main findings of special sample evaluation over a six-year...

Variations in ß(T)-function due to addition of LiI-4AgI system

Impedance spectroscopy measurements of the LiI-4AgI samples, in the frequency range 20 Hz-1 MHz, and in the temperature range between 353 K and 378 K were made. Both pure and lithium-doped silver iodide showed blocking phenomena in the electrodes and the grain boundary. The blocking phenomena allowed a change in the transport properties of the pure compound in respect to the...