Impact of device resistances in the performance of graphene-based terahertz photodetectors.

In recent years, graphene field-effect-transistors (GFETs) have demonstrated an outstanding potential for terahertz (THz) photodetection due to their fast response and high-sensitivity. Such features are essential to enable emerging THz applications, including 6G wireless communications, quantum information, bioimaging and security. However, the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device, so-called access or parasitic resistances. In this work, we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFET detectors. Such dual-gate architectures allow us to fine tune (decrease) the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector, respectively. Our results can be well understood by a series resistance model, as shown by the excellent agreement found between the experimental data and theoretical calculations. These findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

Nanomechanical properties of kidney stones, gallstones and oral stones compared with tap water scale by depth sensing indentation.

This article focuses on a description of research performed to identify structural and mechanical properties differences between calculi in stones, such as gallstones, kidney stones, dental tartar, and saliva gland sialolite, were analyzed and compared with tap water stone, in order to set interrelations. In this study, biological hard pebble-like structures were analyzed and compared among them using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), and Atomic Force Microscopy (AFM). In addition, Nanoindentation was used to obtain values as example in kidney stones the in; stiffness S = 27,827 ± 620 N/nm elastic modulus E = 27.3 ± 4.5 GPa, hardness H = 1.5 ± 0.5 GPa. Samples with the highest amounts of calcium and magnesium oxides were; Tap water stone (39.60%), followed by dental tartar (39.40%), saliva gland sialolite (29.20%), kidney stones (27.70%), and lastly the gallstones (0.30%). Kidney stones showed in particular, whewellite and kaoulinite crystallographic phases, that confers characteristics of greater crystallization with respect to the other stones. Kidney stones positioned in the major hardness stone in human body with 1.5 GPa. In general, samples with the highest amount of calcium oxides, also showed the highest mechanical properties of H and E. Microstructural characteristics and nano-hardness of tap water stone from drinking water where similar to those of dental tartar and saliva gland sialolite, more research still required to associate health concerns and tap water scale derived from drinking water known as hardwater.

Green Synthesis for Carbon Quantum Dots via Opuntia ficus-indica and Agave maximiliana: Surface-Enhanced Raman Scattering Sensing Applications.

In this study, we present an alternative method for synthesizing carbon quantum dots (CQDs) using a green synthesis approach via extracts from Agave maximiliana and Opuntia ficus-indica(Ofi). The extracts from both plants were used as the carbon source for the CQDs. The synthesis method employs mesoporous zeolite 4A as a refractory for the thermal treatment of the samples. Transmission electron microscopy analysis established that the size of the CQDs shows a narrow distribution centered around 2 nm with a maximum size of less than 3 nm for both cases. The CQDs exhibit absorption bands associated with π-π* transitions located around 220 nm. In both cases, photoluminescence (PL) phenomenon was detected by irradiating the samples with a UV wavelength and detecting emissions close to the blue wavelength. Additionally, both kinds of CQDs were tested as surface-enhanced Raman scattering (SERS) substrates against methylene blue (MB), indicating an enhancement associated with ring deformation and stretching modes of the v(C-C) and v(C-N) bonds located around 1400 and 1620 cm-1, respectively. Complementarily, in the framework of density functional theory, H2nC2(2m+1) structures (with n = 3-5 and m = 1-3) were used as a theoretical representation of CQDs in interaction with the MB molecule. It is used for developing the analysis of charge transfer effects between both systems and for specifying elements that generate the SERS effect associated with the chemical enhancement mechanism.

Structural Analysis of Cu+ and Cu2+ Ions in Zeolite as a Nanoreactor with Antibacterial Applications.

In this work, we report the structural analysis of Cu+ and Cu2+ ions in zeolite as a nanoreactor with antibacterial applications. A simple one-step process was implemented to obtain Cu ions in zeolite A (ZA4) by controlling the temperature in the solutions to guarantee the ions' stability. Samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy, showing the characteristic zeolite elements as well as the characteristic bands with slight modifications in the chemical environment of the zeolite nanoreactor attributed to Cu ions by FT-IR spectroscopy. In addition, a shift of the characteristic peaks of ZA4 in X-ray diffraction was observed as well as a decrease in relative peak intensity. On the other hand, the antibacterial activity of Cu ions in the zeolite nanoreactor was evaluated.

Artificial neural networks with conformable transfer function for improving the performance in thermal and environmental processes.

This research proposes a novel transfer function based on the hyperbolic tangent and the Khalil conformable exponential function. The non-integer order transfer function offers a suitable neural network configuration because of its ability to adapt. Consequently, this function was introduced into neural network models for three experimental cases: estimating the annular Nusselt number correlation to a helical double-pipe evaporator, the volumetric mass transfer coefficient in an electrochemical reaction, and the thermal efficiency of a solar parabolic trough collector. We found the new transfer function parameters during the training step of the neural networks. Therefore, weights and biases depend on them. We assessed the models applied to the three cases using the determination coefficient, adjusted determination coefficient, and the slope-intercept test. In addition, the MSE for the training set and the whole database were computed to show that there is no overfitting problem. The best-assessed models showed a relationship of 99%, 97%, and 95% with the experimental data for the first, second, and third cases. This novel proposal made reducing the number of neurons in the hidden layer feasible. Therefore, we show a neural network with a conformable transfer function (ANN-CTF) that learns well enough with less available information from the experimental database during its training.

Artificial neural networks: a practical review of applications involving fractional calculus.

In this work, a bibliographic analysis on artificial neural networks (ANNs) using fractional calculus (FC) theory has been developed to summarize the main features and applications of the ANNs. ANN is a mathematical modeling tool used in several sciences and engineering fields. FC has been mainly applied on ANNs with three different objectives, such as systems stabilization, systems synchronization, and parameters training, using optimization algorithms. FC and some control strategies have been satisfactorily employed to attain the synchronization and stabilization of ANNs. To show this fact, in this manuscript are summarized, the architecture of the systems, the control strategies, and the fractional derivatives used in each research work, also, the achieved goals are presented. Regarding the parameters training using optimization algorithms issue, in this manuscript, the systems types, the fractional derivatives involved, and the optimization algorithm employed to train the ANN parameters are also presented. In most of the works found in the literature where ANNs and FC are involved, the authors focused on controlling the systems using synchronization and stabilization. Furthermore, recent applications of ANNs with FC in several fields such as medicine, cryptographic, image processing, robotic are reviewed in detail in this manuscript. Works with applications, such as chaos analysis, functions approximation, heat transfer process, periodicity, and dissipativity, also were included. Almost to the end of the paper, several future research topics arising on ANNs involved with FC are recommended to the researchers community. From the bibliographic review, we concluded that the Caputo derivative is the most utilized derivative for solving problems with ANNs because its initial values take the same form as the differential equations of integer-order.

Evolving concepts in ventral hernia repair and physical therapy: prehabilitation, rehabilitation, and analogies to tendon reconstruction.

PURPOSE: The abdominal wall and musculoskeletal tendons share many anatomic, physiologic, and functional characteristics. This review aims to highlight these similar characteristics and to present a rationale why the treatment principles of successful musculoskeletal tendon reconstruction, including principles of surgical technique and physical therapy, can be used in the treatment of complex abdominal wall reconstruction or ventral hernia repair. METHODS: The MEDLINE/PubMed database was used to identify published literature relevant to the purpose of this review. CONCLUSIONS: There are several anatomical and functional similarities between the linea alba and musculoskeletal tendons. Because of this reason, many of the surgical principles for musculoskeletal tendon repair and ventral hernia repair overlap. Distribution of tension is the main driving principle for both procedures. Suture material and configuration are chosen to maximize tension distribution among the tissue edges, as seen in the standard of care multistrand repairs for musculoskeletal tendons, as well as in the small bites for laparotomy technique described in the STITCH trial. Physical therapy is also one of the mainstays of tendon repair, but surprisingly, is not routine in ventral hernia repair. The evidence surrounding physical therapy prehabilitation and rehabilitation protocols in other disciplines is significant. This review challenges the fact that these protocols are not routinely implemented for ventral hernia repair, and presents the rationale and feasibility for the routine practice of physical therapy in ventral hernia repair.

Fitting of experimental data using a fractional Kalman-like observer.

In this paper, a fractional order Kalman filter (FOKF) is presented, this is based on a system expressed by fractional differential equations according to the Riemann-Liouville definition. In order to get the best fitting of the FOKF, the cuckoo search optimization algorithm (CS) was used. The purpose of using the CS algorithm is to optimize the order of the observer, the fractional Riccati equation and the FOKF tuning parameters. The Grünwald-Letnikov approximation was used to compute the numerical solution of the FOKF. To show the effectiveness of the proposed FOKF, four examples are presented, the brain activity, the cutaneous potential recordings of a pregnant woman, the earthquake acceleration, and the Chua's circuit response.

Central nervous system development-related microRNAs levels increase in the serum of gestational diabetic women during the first trimester of pregnancy.

MicroRNAs are heterochronic molecules important during brain development, which could be altered by gestational diabetes mellitus (GDM). To explore these molecules in maternal serum, we performed an RT-qPCR analysis. Our results revealed the heterochronic character of some neural development-related microRNA in serum samples of pregnant women. In relation to the first trimester, higher levels of miR-183-5p, -200b-3p, and -125-5p in the second trimester, and higher levels of miR-137 in the third trimester, were found. Furthermore, an insult such as GDM led to higher levels of miR-183-5p, -200b-3p, -125-5p, and -1290 relative to the control in the first trimester, which might be related to changes in neurogenesis and cell proliferation. An in silico analysis suggested that increased microRNAs in the second trimester in the control contributed to cell proliferation and neuron differentiation and that the rise in miR-137 in the third trimester led to neuron maturation. In the diabetic, higher levels of the microRNAs in the first trimester suggested alterations in cell proliferation and neuron differentiation. In conclusion, we showed that fetal-related microRNAs can be detected in the serum of pregnant woman and exhibit temporary regulation during pregnancy and that microRNAs involved in cell proliferation and neuron differentiation are upregulated under GDM.

Turbulent Kinetic Energy in the Energy Balance of a Solar Flare.

The energy released in solar flares derives from a reconfiguration of magnetic fields to a lower energy state, and is manifested in several forms, including bulk kinetic energy of the coronal mass ejection, acceleration of electrons and ions, and enhanced thermal energy that is ultimately radiated away across the electromagnetic spectrum from optical to x rays. Using an unprecedented set of coordinated observations, from a suite of instruments, we here report on a hitherto largely overlooked energy component-the kinetic energy associated with small-scale turbulent mass motions. We show that the spatial location of, and timing of the peak in, turbulent kinetic energy together provide persuasive evidence that turbulent energy may play a key role in the transfer of energy in solar flares. Although the kinetic energy of turbulent motions accounts, at any given time, for only ∼(0.5-1)% of the energy released, its relatively rapid (∼1-10 s) energization and dissipation causes the associated throughput of energy (i.e., power) to rival that of major components of the released energy in solar flares, and thus presumably in other astrophysical acceleration sites.

Comparación delpperfil lipídico por sexo y edad en ovinos / Comparson of lippid profile by sex and age in sheeps

Se comparó el perfil lipídico y la correlación entre los componentes lipídicos del suero en cuatro grupos de ovinos. A tal fin, se tomaron muestras de sangre de 98 ovinos en ayuno, diferenciados por género y edad (23 machos y 25 hembras mayores de un año de edad; 22 machos y 28 hembras menores a un año). Se determinaron las concentraciones séricas de: triglicéridos, colesterol total (CT) y colesterol de lipoproteínas de alta densidad (C-HDL) mediante el método enzimítico colorimétrico. El colesterol de lipoproteína de muy baja densidad (C-VLDL) y de baja densidad (C-LDL) se determinó usando la fórmula de Friedewald. Las medias para CT, triglicéridos, C-HDL, C-VLDL y C-LDL (mg/dL) fueron de 86.19, 21.57, 39.32, 4.31 y 42.55, respectivamente. En el grupo de adultos existe diferencia significativa (P <0.05) en los niveles de: CT (P <0.0003), C-HDL (P < 0.0007) y C-LDL (P <0.0133), siendo más alto en hembras; las hembras jóvenes presentaron elevado el C-HDL (49.02 mg/dL). Hay diferencias en los machos en el CT (P <0.0138 ) y C-LDL (P <0.0006) y en hembras sólo en el CT (P <0.015). Los valores de triglicéridos y C-VLDL en hembras (P >0.90 para ambos), machos (P >0.405 para ambos), jóvenes (P >0.487 para ambos) y adultos (P >0.179 para ambos) no mostraron diferencias significativas (P -valor >0.05) con un nivel de confianza del 95.0%. En conclusión, debido a las diferencias estadísticamente significativas en las comparaciones del perfil lipídico entre grupos de ovinos, pueden ser considerados cuatro perfiles lipídicos: machos adultos, hembras adultas, machos jóvenes y hembras jóvenes.

To objective was to compare the lipid profile in sheep and to analyze the relationship between serum lipids levels of four groups. Blood samples from 98 sheep were obtained in fasting state, differentiated by gender and age (23 males and 25 female aged over 12 months; 22 males and 28 females aged under 12 months). Serum concentrations of total cholesterol (TC), triglycerides and high density lipoprotein cholesterol (HDL-C) were measured using enzymatic colorimetric method; levels of very low-density lipoprotein cholesterol (VLDL-C) and low-density lipoprotein cholesterol (LDL-C) were determined using Friedewald equation. Mean for TC, triglycerides, HDL-C, VLDL-C and LDL-C were: 86.19, 21.57, 39.32, 4.31, 42.55 mg/dL respectively. The group of adults was differ (P < 0.05) for TC (P <0.0003), HDL-C (P <0.0007) and LDL-C (P <0.0133), being increased in females. In young females HDL-C was higher (49.02 mg/ dL). In males significant differences were observed in TC (P <0.0138), and LDL-C (P <0.0006) and females in TC (P <0.015). Triglycerides and VLDL-C in females (P >0.90 for both), in males (P <0.405 for both), in young (P >0.487 for both) and adults (P >0.179 for both) showed no significant differences (P-value >0.05) with a confidence level of 95.0%. In Conclusion given the differences in the comparisons between groups for the lipid profile in sheep, can be considered four lipid profiles as follows: adult males, adult females, young males and young females.

PRIMER REPORTE DE Cryptosporidium parvum EN TERNEROS HOLSTEIN (Bos taurus) DE MANIZALES, CALDAS, COLOMBIA / FIRST REPORT OF Cryptosporidium parvum IN HOLSTEIN CALVES (Bos taurus) FROM MANIZALES, CALDAS, COLOMBIA

El objetivo de este estudio fue identificar especies o genotipos del protozoario parásito Cryptosporidium presentes en heces colectadas de terneros Holstein del municipio de Manizales, Departamento de Caldas, Colombia. El ADN fue extraído a 80 muestras de materia fecal, de las cuales 11 fueron diagnosticadas positivas para Cryptosporidium spp., mediante reacción en cadena de la polimerasa (PCR). El análisis PCR-RFLP del locus 18S ADNr, identificó la presencia de Cryptosporidium parvum en todas las muestras positivas analizadas. Este hallazgo sugiere que el ganado puede ser una fuente potencial de infección por Cryptosporidium en humanos y se constituye en el primer reporte publicado de C. parvum en bovinos de Manizales, Caldas.

The objective of this study was to identify species or genotypes of Cryptosporidium parasite present in feces collected from Holstein calves in Manizales city, Caldas Department, Colombia. DNA was extracted from 80 fecal samples, which 11 were diagnosed positive for Cryptosporidium spp., by the Polymerase Chain Reaction method. PCR-RFLP analysis of 18S rDNA locus identified the presence of Cryptosporidium parvum in all samples tested positive. This finding suggests that cattle may be a potential source of human infection by Cryptosporidium, and it becomes the first published report of C. parvum in cattle in Manizales, Caldas.

The autonomic condition of children with congenital hypothyroidism as indicated by the analysis of heart rate variability.

Early treatment by thyroid hormone in congenital hypothyroidism (CH) prevents for mental retardation, but the autonomic condition could well remain impaired. The aim of this study was to get insights about the cardiovascular regulation of CH children by analysing their heart rate variability (HRV) data. RR-interval data of 34 early treated CH children, 24 to 48 months of age, were collected at rest in a clinical environment. In all these cases, CH resulted from an abnormal development of thyroid gland. Data from 29 age matched-controls were also collected in a scholar environment. Short time series were then analysed in time and frequency domains. Detrended fluctuation analysis (DFA) was also applied to obtain the scaling exponent α(1). We found that the HRV obtained from children with CH is diminished as suggested by statistical differences (p<0.05) in the following parameters: RMSDD, pNN20, total power, LF and HF. However, no significant differences were found in the LF/HF ratio, the central frequencies of the LF and HF bands, as well as in α(1). Given that the significant differences were basically reflected in static parameters rather than in the frequency distribution or scale-invariant behaviour of the studied data, we consider that the analysis points toward the effect of treatment on rising heart rate by the thyroid hormone, and not necessarily toward any residual autonomic dysfunction, as the dominant underlying cause of the diminished HRV exhibited by CH children.

Repeatability of heart rate variability in congenital hypothyroidism as analysed by detrended fluctuation analysis.

The analysis of heart rate fluctuations, or heart rate variability (HRV), may be applied to explore children's neurodevelopment. However, previous studies have reported poor reliability (repeatability) of HRV measures in children at rest and during light exercise. Whether the reliability can be improved by controlling variables such as physical activity, breathing rate and tidal volume, or by selecting non-conventional techniques for analysing the data remains as an open question. We evaluated the short-term repeatability of RR-interval data from medicated children with congenital hypothyroidism (CH). The alpha(1) exponents, obtained by detrended fluctuation analysis (DFA), from the data of 21 children collected at two different sessions were compared. Elapsed days between sessions were 59 +/- 33, and data were obtained during 10 min, trying to restrict the children's activity while being seated. We found statistical agreement between the means of alpha(1) exponents for each session (p = 0.94) and no bias with a low-coefficient variation (9.1%); an intraclass correlation coefficient ri = 0.48 ([0.14 0.72], 95% confidence interval) was also estimated. These findings, which were compared with results obtained by conventional time and frequency techniques, indicate the existence of agreement between the alpha(1) exponents obtained at each session, thereby providing support concerning the repeatability of HRV data as analysed by DFA in children with congenital hypothyroidism. Of particular interest was also the agreement found by using the central frequency of the high-frequency band and the parameter pNN20, both showing better or similar ri than alpha(1) (0.77 [0.57 0.89] and 0.51 [0.17 0.74], respectively), yet considerably better repeatability than other conventional time and frequency parameters.

Historias clínicas y partes diarios para investigación: herramientas para estudios de carcinogénesis en modelos animales / Clinical histories and daily reports for research

Los bioterios suelen no tener personal disponible para llevar un registro adecuado del desarrollo de una experiencia en particular. Pueden perderse datos relevantes o no anticiparse efectos adversos. El impacto es mayor en experimentos a largo plazo, como el estudios de la carcinogénesis. Nuestro grupo desarrolló modelos de historias clínicas (HC) y partes diarios para investigación (PDI) que incluyen procedimientos estandarizados para su confección. Objetivo: demostrar que el uso de HC y PDI permite realizar el seguimiento diario de animales de experimentación por largos períodos y complementa la formación de recursos humanos. Materiales y métodos: se usó como modelo de HC la utilizada por el Grupo Oncológico Cooperativo del Sur (GOCS). En la confección del PDI se consideraron los objetivos del estudio, variables ambientales y bienestar animal. Se entrenó a alumnos avanzados para el manejo de estas herramientas. Resultados: durante 370 días se cumplieron seguimientos diarios en : controles ambientales, cuidado de los animales y prácticas generales. La limpieza de la cama y la detección de ruidos fueron las variables que se recogieron con más frecuencia. El sangrado de fosas nasales, pérdida de pelo y lesiones en piel y mucosas fueron las observaciones más comunes. Se obtuvieron datos para análisis interinos y retrospectivos de posible utilidad a la hora de interpretar resultados. Conclusiones: estas sencillas herramientas, HC y PDI, simplificaron y optimizaron la observación diaria de los animales, pudiéndose realizar acciones correctivas rápidas y permitiendo que alumnos avanzados puedan entrenarse en el manejo de animales de experimentación

Historias clínicas y partes diarios para investigación: herramientas para estudios de carcinogénesis en modelos animales / Clinical histories and daily reports for research

Los bioterios suelen no tener personal disponible para llevar un registro adecuado del desarrollo de una experiencia en particular. Pueden perderse datos relevantes o no anticiparse efectos adversos. El impacto es mayor en experimentos a largo plazo, como el estudios de la carcinogénesis. Nuestro grupo desarrolló modelos de historias clínicas (HC) y partes diarios para investigación (PDI) que incluyen procedimientos estandarizados para su confección. Objetivo: demostrar que el uso de HC y PDI permite realizar el seguimiento diario de animales de experimentación por largos períodos y complementa la formación de recursos humanos. Materiales y métodos: se usó como modelo de HC la utilizada por el Grupo Oncológico Cooperativo del Sur (GOCS). En la confección del PDI se consideraron los objetivos del estudio, variables ambientales y bienestar animal. Se entrenó a alumnos avanzados para el manejo de estas herramientas. Resultados: durante 370 días se cumplieron seguimientos diarios en : controles ambientales, cuidado de los animales y prácticas generales. La limpieza de la cama y la detección de ruidos fueron las variables que se recogieron con más frecuencia. El sangrado de fosas nasales, pérdida de pelo y lesiones en piel y mucosas fueron las observaciones más comunes. Se obtuvieron datos para análisis interinos y retrospectivos de posible utilidad a la hora de interpretar resultados. Conclusiones: estas sencillas herramientas, HC y PDI, simplificaron y optimizaron la observación diaria de los animales, pudiéndose realizar acciones correctivas rápidas y permitiendo que alumnos avanzados puedan entrenarse en el manejo de animales de experimentación (AU)

Double modulation of 5-fluorouracil by trimetrexate and leucovorin in patients with advanced colorectal carcinoma.

The purpose of this report is to evaluate the efficacy and toxicity (Tx) of a double modulation of 5-fluorouracil (5-FU) by trimetrexate (TMTX) and leucovorin (LV) in patients with advanced recurrent (inoperable) or metastatic colorectal cancer (ACC). Between December 1997 and August 2000, 36 patients were entered in this phase II study. Median age was 61 years, and 18 patients (50%) were female. Median performance status was 0 (range: 0-1), whereas primary tumor location was colon in 21 patients (58%) and rectum in 15 patients (42%). The number of metastatic sites was 1:29 patients (81%); 2:6 patients (17%) and 3:1 patient (3%). Hepatic involvement was observed in 33 patients (92%). Treatment consisted of TMTX 110 mg/m2 IV over 1 hour at hour (H) 0; LV 50 mg/m2 IV over 2 hours IV infusion starting at H 18; and 5-FU 900 mg/m2 IV bolus at H 20. LV (rescue) 15 mg/m2 orally was administered every 6 hours (total 6 doses) beginning at H 24. Cycles were repeated every 2 weeks until progressive disease (PD) or severe Tx. Thirty-four patients are assessable for response (R) (two patients refused further treatment after the first course of therapy), whereas all patients were assessable for Tx. Complete response: 1 patient (3%); partial response: 4 patients (12%), with an overall objective response rate of 15% (95% CI, 1%-25%); no change: 12 patients (35%); and progressive disease: 17 patients (50%). The median time to treatment failure was 4 months and median survival was 11 months. Tx was within acceptable limits. The dose-limiting side effect was mucositis. Eight episodes of grade II or III stomatitis were observed and were responsible for dosage modifications of TMTX and 5-FU. Leukopenia was observed in 16 patients (44%); neutropenia was registered in 19 patients (53%); anemia was seen in 18 patients (50%); emesis in 22 patients (61%); and dermatitis in 3 patients (8%). There were no therapy-related deaths. The double modulation of 5-FU by TMTX and LV showed modest antitumoral activity with mild to moderate Tx.

Caracterizacion genetica y morfologica de las poblaciones de Cyprinodon dear-borni (Atherinomorpha: Cyprinodontidae) en Chacopata y Laguna de los Patos, Venezuela / Genetic and morphological characteristics of the populations of Cyprinodon dearborni (Atherinomorpha: Cyprinodontidae) in Chacopata and Laguna de los Patos, Venezuela

Two populations of the fish Cyprinodon dearborni were compared, one from Laguna de Chacopata and the other from Laguna de los Patos, Cumana, Venezuela. The morphometric method of the Box Truss was used; the organisms were photographed with a digital camera. In the images 18 measures were made to each organism, with the MOCHA 1.2 program. The tendencies of morphologic variation among populations were analyzed by main components using STATGRAPHICS 2.0 and SHEAR programs. The first four main components in males and females explained 88 of the total variation. The components two, three and four separate the two populations based on the body form of the animals. For the electrophoretic study, 13 enzymatic systems were analyzed in starch gels. The variation and genetic distance were calculated with the program GENES 2.0. Differences were observed in the systems G6PDH, GPI; ES and GLUD, that which can be used as isoenzimatic markers. Genetic diversity of Chacopata (H = 0.086, p = 0.079) was higher than in Laguna de los Patos (H = 0.029, p = 0.028), but both are within the average in populations of fish. The two populations presented a Nei distance of 0.058. The genetic and morphologic differentiation suggests an incipient process of separation whose causes could be the ecological conditions of their habitat, or processes of vicariant speciation.