Aspects of the biology of Cichlasoma uropthalmus (Gunther) with particular reference to its culture

This thesis is an investigation of the basic biology, reproductive behaviour, and key physiological and nutritional requirements of the Mexican and Central American cichlid Cichlasoma urophthalmus (Gunther), with particular reference to the potential of native species for aquaculture in the region. C. urophthalmus is a widely appreciated food fish within its native range, commanding good prices and having the advantage in terms of aquaculture that the risk from introduction of an exotic species with the consequent importation costs, diseases and escapes are eliminated. The dentition, gill rakers and gut structure are indicative of a carnivorous habit and this was corroborated by seasonal examination of gut contents which revealed that the species feeds principally on small animals. Investigation of the species in the natural environment suggest that growth was continuous, with some slight depression in the cooler winter months, reproduction occurred in the second year and the minimum reproductive size was 102cm (50g). In the laboratory C. urophthalmus grew well between 22.5 and 36.3°C the best growth being achieved at 32°C and optimum growth and survival (- production) being at 28°C. The species is typically euryhaline and can be acclimated to salinities of 0% to 35%. It can withstand instantaneous transfer from O to 15%, and reverse, and have best growth at 15%, probably due to the energy saving in an isotonic medium. Oxygen consumption rates were similar to other cichlids and C. urophthalmus can survive virtual anoxia for about 2h. C. urophthalmus is a bottom-spawner and the aggressive features of its reproductive behaviour, described in this work, can probably be minimized in culture. Its fecundity is about 5 to 7 times that of the mouth brooding tilapias, producing 2000-7000 eggs per spawn and it can reproduce at about 23 days intervals, probably throughout the year with management of temperature. Hatching is rapid (61 days) and survival good with simple hatchery techniques. Broodstock requirements, handling and labour costs could be lower than for the mouth brooding tilapias. The protein requirements of fry were shown to be 39-45% of the diet and this is similar to the tilapias. Diet digestibility was depressed by high dietary fibre content, but was not inhibited by inclusion of soybean (25.81%) or wheat meal (26.7%) in the diets. Although much more research is required. The results reported here have enabled tentative formulations of diets for aquaculture, based on typically available ingredients. The features of C. urophthalmus are discussed and compared extensively with those of the other cultured fish, principally the tilapias. It is concluded that C. urophthalmus is a very good candidate for aquaculture development within its range of distribution and that it has strong advantages over introduction of cultured cichlids

On some properties of CV_{(0)}(X, A)

Let X be a completely regular Hausdorff space and V a Nachbin family on X. For a locally convex algebra A, let CV(0)(X, A) be the algebra of all weighted vector-valued continuous functions with the topology given by the uniform seminorms induced by V . In this paper we study some properties of A that are inherited by CV(0)(X, A). These properties are related to the unit element, spectral seminorms and uniformly A-convex property

Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor

Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fish is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads)2 desaturases have undergone during evolution. We previously showed that Chirostoma estor, one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl)5 elongase and two Fads2 desaturases displaying Δ4 and Δ6/Δ5 specificities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C18 PUFA. In addition, the specificities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fish lineages

Sistema de transformacion, regulacion, suministro y almacenamiento de corriente continua a menor escala por energía solar para dispositivos electrónicos

En el presente documento se presenta el procedimiento de un sistema de recepción de energía solar controlado por Microcontrolador PIC, el cual está encaminado al aporte físico de un dispositivo electrónico capaz tener una óptima admisión de dicha energía, transformarla a energía eléctrica y posteriormente almacenarla en una batería. Se tiene como elemento base el aprovechamiento de un recurso natural como lo es el sol, el cual a través de los tiempos hace más notorio y asimismo es fácil su concepción

El efecto del nivel de proteína y lípidos sobre la acción dinámica específica y la excreción postprandial en sub-adultos del camarón blanco Litopenaeus vannamei

The study aimed to evaluate the effect of 4 levels of dietary protein (20, 30, 40 and 50%) and lipids (2, 4, 8 and 16%) on the magnitude and duration of specific dynamic action (SDA) and postprandial nitrogen excretion in the subadult white shrimpLitopenaeus vannameiusing computer-controlled metabolic chambers (continuous-flow respirometer). We determined the oxygen consumption rate at 1 h intervals until the postprandial oxygen consumption rate returned to the pre-feeding level. Shrimp fed all the diets had significantly higher respiration rates after feeding due to the SDA. Oxygen consumption, the SDA coefficient and the SDA magnitude increased notably with increasing dietary protein content. Shrimp fed the 20% protein diet had the lowest levels of pre- and post-feeding respiration and the smallest SDA. A significant change in the SDA coefficient relative to each lipid level was not demonstrable. Additionally, nitrogenous excretion increased with an increase of dietary protein but not with an increase of lipid level. By estimating the SDA of subadults, the response to standard metabolic rate (SMR) was lower than that reported for juveniles and postlarva white shrimp

Efficacy and sex-specific outcomes after six episodes of percutaneous tibial nerve stimulation treatment on overactive bladder syndrome symptoms

ObjectiveThis study aimed to investigate the efficacy of six episodes of percutaneous tibial nerve stimulation (PTNS) treatment for overactive bladder (OAB) symptoms in men and women and to determine the duration of the effects over a 6-month period.MethodsWomen and men with OAB symptoms participated in the study, which was conducted in accordance with an approved ethical protocol (ISRCTN15733799). Patients underwent six 30-min PTNS sessions, twice per week. The symptoms of OAB were assessed using a voiding diary, the short form of the Overactive Bladder Symptom Score questionnaire (OAB-q SF), and the Patient Perception of Bladder Condition (PPBC), which were self-completed by patients before and after treatment (24 h and at 1, 3, and 6 months). The outcome data were compared for sex and time points using two-way ANOVA for repeated measures.ResultsPTNS treatment significantly improved the OAB symptoms and quality of life in men and women. PTNS increased the voided volume (p < 0.05) and decreased the frequency of voiding, nocturia, and urgency at 24 h and up to 6 months (p < 0.001). The OABq-SF and PPBC scores were significantly decreased after PTNS (p < 0.001). Urgency was greater in men than in women. The duration of PTNS clinical success on frequency and the perception of improvement in quality of life were greater in women than in men.ConclusionThe clinical effects of six sessions of PTNS strongly suggest its potential for shortening, from the standard 12 sessions, to effectively alleviate symptoms of OAB. This therapeutic procedure would reduce both the time and economic costs of OAB treatment

Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance

[EN]In typical terahertz time-domain spectroscopy systems, the use of the lock-in technique is necessary because of the low current induced at the receiver so that the laser pump beam must be modulated (chopped) at a frequency much lower than the laser repetition rate. This work shows that, in the case of semi-insulating GaAs (SI-GaAs) antennas, this modulation has an important effect on the antenna current and consequently, on the radiated electromagnetic pulse. There exists a threshold bias (whose value depends on the chopping frequency) where an abrupt increase in the current and consequently, in the terahertz emission takes place. The calculated energy of the pulse below and above the threshold shows that the energy doubles. The exact bias voltage at which this occurs changes with the laser modulation frequency when this is below 350 Hz, but at higher frequencies, the threshold remains almost constant. The experiments show that the responsibility for this behavior is the S-shape negative differential conductance exhibited by SI-GaAs originated by a slow field-enhanced charge trapping mechanism, which is also an important source of noise at the receiver of the system.SpanishMINECO and FEDER under Project TEC2017-83910-R and in Junta de Castilla y León and FEDER under Project SA254P1

Identification of vaginal microbiome associated with IVF pregnancy

The factors that cause a preterm birth (PTB) are not completely understood up to date. Moreover, PTB is more common in pregnancies achieved by in-vitro fertilization (IVF) than in spontaneous pregnancies. Our aim was to compare the composition of vaginal microbiome at 12 weeks of gestation between women who conceived naturally or through IVF in order to study whether IVF PTB-risk could be related to vaginal microbiome composition. We performed an observational, prospective and multicentre study among two public hospitals and a fertility private clinic in Spain. Vaginal swabs from 64 pregnant women at 12 weeks of gestation were collected to analyse the microbiome composition by sequencing the V3–V4 region of the 16S rRNA. Our results showed that the vaginal microbiome signature at 12 weeks of pregnancy was different from women who conceived naturally or through IVF. The beta diversity and the genus composition were different between both cohorts. Gardnerella, Neisseria, Prevotella, and Staphylococcus genus were enriched genus in the vaginal microbiome from the IVF group, allowing us to create a balance model to predict both cohorts. Moreover, at species level the L. iners abundance was higher and L. gasseri was lower in the IVF group. As a conclusion, our findings were consistent with a proposed framework in which IVF pregnancy are related to risk for preterm birth (PTB) suggesting vaginal microbiome could be the reason to the relation between IVF pregnancy and risk for PTB

Precauciones de manejo ante posibles complicaciones en pólipos intestinal

Los pólipos intestinales usualmente suelen ser asintomáticos o cursan con síntomas muy inespecífico, esto aporta a que la gran cantidad de pacientes solo acuden a la consulta medica cuando presentes complicaciones complejas o desarrollen cáncer colorectal. Desde el punto de vista quirúrgico las complicaciones provocadas por un pólipo intestinal suelen ser complejas. Sin embargo existen procedimientos quirúrgicos de vanguardia como la cirugía endoscópica y laparoscópica combinada que ha presentado menos complicaciones en torno a su aplicación. Las prevención principal para el desarrollo de complicaciones pasa por el screening endoscópico cada cierto tiempo, sobre todo en pacientes con factores de riesgo presentes

Almidones de Cáscara de Yuca (Manihot Esculenta) y Papa (Solanum Tuberosum) para Producción de Bioplásticos: Propiedades Mecánicas y Efecto Gelatinizante

  Los productos biodegradables basados en materias primas agrícolas ocupan un gran espacio en las investigaciones para el desarrollo y mejoramiento de bioplástico a base de almidón que presentan propiedades similares a los plásticos convencionales. El objetivo de este trabajo consistió en describir la gelatinización y propiedades mecánicas de bioplásticos extraídos de almidones tanto de cáscaras de yuca (Manihot esculenta) como de cáscaras de papa (Solanum tuberosum). A partir de una revisión bibliográfica literaria complementada con aproximadamente 86 artículos científicos se logró comprobar que la gelatinización de estos residuos en función de sus propiedades fisicoquímicas y funcionales, mejoran sus propiedades mecánicas, además la adición de sustancias poliméricas sintéticas y naturales, plastificantes, materiales de relleno, aditivos, agentes acoplantes, agentes desestructurantes y agua otorgaron las propiedades mecánicas necesarias para trabajar como un termoplástico. Si bien ambos almidones presentan propiedades mecánicas viables para la elaboración de biopolímeros, se logra concluir que el almidón de cáscara de papa puede alcanzar un bioplástico con mejores propiedades mecánicas debido a que presenta gránulos más esféricos y regulares, los cuales pueden formar estructuras moleculares más estables, así como su alto contenido de amilosa favorece en la gelatinización y logra que la fuerza de tensión presente un incremento en comparación al almidón de cáscara de yuca.   Palabra clave: Almidón, gelatinización, papa, propiedades mecánicas, yuca.   Abstract Biodegradable products based on agricultural raw materials occupy a large space in research for the development and improvement of starch-based bioplastics that have properties similar to conventional plastics. The objective of this work was to describe the gelatinization and mechanical properties of bioplastics extracted from starches both from cassava peels (Manihot esculenta) and potato peels (Solanum tuberosum). From a literary bibliographic review complemented with approximately 86 scientific articles. it was possible to verify that the gelatinization of these residues based on their physicochemical and functional properties, improves their mechanical properties. Moreover, the addition of synthetic and natural polymeric substances, plasticizers, fillers, additives, coupling agents, destructuring agents, and water will give the necessary mechanical properties to work as a thermoplastic. Although both starches have viable mechanical properties for the production of biopolymers, it is possible to conclude that potato peel starch can achieve a bioplastic with better mechanical properties due to the fact that it presents more spherical and regular granules, which can form more stable molecular structures; as well as, its high amylose content favors gelatinization and achieves an increase in the tensile strength compared to cassava shell starch.  Keywords: Gelatinization, mechanical properties, yucca, potato, starch