bluuebunny/crossref_metadata_2025 huggingface dataset:
Fieldwide Determination of Directional Permeabilities Through Transient Well Testing
Authors: Carpenter Chris
Published: March 2017

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 181437, “Fieldwide Determination of Directional Permeabilities Using Transient Well Testing,” by Yan Pan, Medhat Kamal, and Wayne Narr, Chevron, prepared for the 2016 SPE Annual Technical Conference and Exhibition, Dubai, 26–28 September. The paper has not been peer reviewed.

Knowledge of the maximum- and minimum-permeability directions in anisotropic reservoirs helps to optimize injector and producer locations and is important for reservoir management, especially under secondary or enhanced recovery of hydrocarbons. The complete paper describes a method using transient-test data rich with dynamic information aiming to provide fieldwide permeability distribution in well-spacing scale, which is relevant for estimating fluid movement and recovery.

Introduction

The knowledge of flow communication between wells is key information for reservoir management, especially in secondary or tertiary recovery. The surveillance methods to collect dynamic data to gain such knowledge include multiple-well pressure-transient tests and tracer tests. The measurements of tracer agents arriving at producing wells provide direct confirmation of flow communication. Interwell transient tests derive similar information through the measurement of pressure responses (at observation wells) to the production- or injection-rate changes at an active well, and the time required to conduct such tests is much shorter than the time required to conduct tracer tests. For anisotropic reservoirs, such as naturally fractured fields or channel systems, knowing the permeability tensor directions and the ratios of the maximum to the mini-mum permeability in various locations in the field provides better opportunities to make optimal operational decisions.

All previously proposed methods in the literature require three sets of interference or pulse tests among wells offset at different azimuths, and the pressure-response data are analyzed simultaneously using type-curve matching to calculate permeability tensors. In practice, there is limited opportunity to conduct all three sets of interference tests through the same well at one time and to analyze them simultaneously to derive a permeability tensor. In the complete paper, a new method is proposed that uses previous test-analysis results directly to estimate the permeability tensor. The analysis results (the permeability and porosity of the fast path linking two wells) from a single set interwell (interference or pulse) test could be obtained using any modern techniques with analytical, semi analytical, or numerical models and would not be limited to conventional type-curve matching. The algorithm uses mathematical matrix operations, and all analysis results can be integrated to generate the field permeability-tensor map. Mathematical aspects of the method, as well as method validation, are discussed in the complete paper.
Technology Focus: Formation Damage (February 2017)
Authors: Fleming Niall
Published: March 2017

Technology Focus

In a corresponding article from 2015, I quoted the title of Brant Bennion’s 1999 article “Formation Damage—The Impairment of the Invisible, by the Inevitable and Uncontrollable, Resulting in an Indeterminate Reduction of the Unquantifiable.” I would like to think that, given the considerable effort spent on drilling- and completion-fluid development since the article was written, we have a much better control of the “inevitable and uncontrollable.” Likewise, with respect to a “reduction in the unquantifiable,” much of the uncertainty can be minimized by performing representative corefloods using plugs of different permeability value to reflect the values expected downhole. It is permeability that is often the most difficult to quantify; therefore, focusing on permeabilities in coreflooding to cover the span of those likely to be encountered can improve our understanding of the potential formation damage that could be expected. 

In this short article, I would like to focus on “the impairment of the invisible” because it is here that the greatest uncertainty exists with regard to formation-damage evaluation.  One of the challenges for those involved with understanding an unexpected decline in well performance is identifying the exact causes for the reduced productivity because we cannot see downhole what type of damage has occurred and where.  Production engineers can use significant amounts of time in attempting to identify a cause for poor productivity. This process involves evaluating all that has happened in the well, which includes the fluids used, losses during drilling and completion, lower-completion type and potential for plugging, and how effective well cleanup was. Consideration of all data available can eventually point toward one factor that could explain productivity decline. Core-flooding can also be used to simulate the sequences performed in the well, to try to identify the damaging mechanism. Regardless of those factors, the key take-home message is that prevention is much better than cure.

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 178963 Laboratory Simulation and Damage in Openhole Water Injectors by Michael Byrne, LR Senergy, et al.

SPE 178018 Evaluation of Damage Mechanisms in Tight Gas Reservoirs: Field Example From Perth Basin by Nick Bahrami, SGS Netherlands, et al.

SPE 179007 Ability of a Filter-Cake Breaker To Diffuse Into Completion Brine and Packed Gravel by Clotaire-Marie Eyaa Allogo, Schlumberger, et al.
Effects of Grazing Management and Buffer Strips on Metal Runoff from Pastures Fertilized with Poultry Litter
Authors: Pilon C. , Moore P. A. , Pote D. H. , Martin J. W. , DeLaune P. B.
Published: March 2017

Metal runoff from fields fertilized with poultry litter may pose a threat to aquatic systems. Buffer strips located adjacent to fields may reduce nutrients and solids in runoff. However, scant information exists on the long‐term effects of buffer strips combined with grazing management on metal runoff from pastures. The objective of this study was to assess the 12‐yr impact of grazing management and buffer strips on metal runoff from pastures receiving poultry litter. The research was conducted using 15 watersheds (25 m wide and 57 m long) with five treatments: hayed (H), continuously grazed (CG), rotationally grazed (R), rotationally grazed with a buffer strip (RB), and rotationally grazed with a fenced riparian buffer strip (RBR). Poultry litter was applied annually in spring at 5.6 Mg ha−1. Runoff samples were collected after every rainfall event. Aluminum (Al) and iron (Fe) concentrations were strongly and positively correlated with total suspended solids, indicating soil erosion was the primary source. Soluble Al and Fe were not related to total Al and Fe. However, there was a strong positive correlation between soluble and total copper (Cu) concentrations. The majority of total Cu and zinc was in water‐soluble form. The CG treatment had the highest metal concentrations and loads of all treatments. The RBR and H treatments resulted in lower concentrations of total Al, Cu, Fe, potassium, manganese, and total organic carbon in the runoff. Rotational grazing with a fenced riparian buffer and converting pastures to hayfields appear to be effective management systems for decreasing concentrations and loads of metals in surface runoff from pastures fertilized with poultry litter.

Core Ideas

Increased aluminum and iron loads in runoff were related to higher sediment delivery.

A positive correlation was observed between soluble and total copper concentrations.

Continuously grazed watersheds yielded the largest metal loads in runoff.

Metal concentrations in runoff were lower in hayed plots than the other treatments.

Rotational grazing with a fenced riparian buffer reduced metals in runoff effectively.
Nitrogen Fertilization Rates Influence Stockpiled Tall Fescue Forage through Winter
Authors: Kallenbach Robert , Roberts Craig , Lory John , Hamilton Stacey
Published: March 2017

Tall fescue [Lolium arundinaceum (Schreb.) Darbyish.] can be autumn stockpiled to extend the grazing season. The objectives of this study were to determine (i) optimum mid‐August N fertilization rate for stockpiled yield with or without red clover (Trifolium pratense L.), (ii) if mid‐August N applications affect the persistence of red clover in a mixed sward, (iii) how N fertilization rates affect total ergot alkaloids (TEA) in November, and (iv) if N fertilization rates and harvest months affect nutritive value through winter. At the University of Missouri Forage Systems Research Center near Linneus, MO, five N fertilization rates were applied in mid‐August and forage was harvested the following November through March. Dry matter yield, crude protein (CP), and in vitro true digestibility (IVTD) were determined for each sampling date. Each November, TEA were measured from tall fescue‐only plots. Red clover densities were determined each June. Stockpiled yields increased with increasing N fertilization rates up to 168 kg N ha−1. Red clover neither impaired nor improved stockpiled forage yield. Red clover densities decreased linearly as N fertilization rate increased the previous August. Sward type affected nutritive value minimally. Losses in CP and IVTD through winter averaged 20 and 60 g kg−1, respectively, over the 4 yr. Application of 56 kg N ha−1 provided forage with CP concentrations that would support nonlactating beef cows. Fertilization rates of ≥112 kg N ha−1 resulted in November TEA concentrations that are toxic to grazing livestock. For optimum stockpiled forage yields, forage should be fertilized with <112 kg N ha−1 and grazed before January.
Tetrafluorobenzyl Alcohol-Oriented Novel (S)-Enantiomeric Esters: Synthesis and Structure-Activity Relationship
Authors: Wang Wenda , Su Haihuan , Li Huangyong , Cao Xiufang
Published: March 2017

Background:

Using constantly and widely chemistry insecticides has resulted in a selection
burden and favored tolerance development in various insect species. Particularly, pyrethroids are the
only one which can be used for net impregnation either ITNs or LLIN as yet, however, the excessive
use of pyrethroids has led to many cases of insect resistance in worldwide. Therefore, it is urgent to
develop novel insecticides fighting against this sort of resistance.

Methods:

Based on the preliminary studies, we explored a straightforward highly stereoselective
method to achieve the novel chiral ester derivatives by using Oppolzer’s 10,2-camphorsultam as chiral
controlling reagent.

Results:

A series of tetrafluorobenzyl alcohol oriented (S)-enantiomeric esters were designed and synthesized
by the asymmetric synthesis. All the compounds exhibited moderate yields, and the original
synthesized compounds have been evaluated for their potential insecticidal activity against Plutella
xylostella compared with those of fenvalerate and D-trans-phenothrin, and some compounds presented
excellent insecticidal activities.

Conclusion:

The bioassay illustrated that some of the compounds exhibit obviously insecticidal activities
against Plutella xylostella, especially, the insecticidal activity of compound 5i was as good as
commercial fenvalerate and D-trans-phenothrin, which can be used as a lead compound for further optimization.
MANIPULATIVE COOPERATION POLITICS OF MLM COMPANIES IN SURABAYA CITY
Authors: Andriati Retno
Published: March 2017

Many studies on multi-level marketing business from law, management, marketing economic and anthropology perspectives have been focused on its legality which is victims of MLM companies/fake MLM companies. Studies on market phenomenon and entrepreneurship of MLM large industry fromeconomy anthropology perspective are still rare especially in Indonesia. The study is intended to identify the underlying cooperation policy as well as manipulative conduct of MLM business in Surabaya.The study employs qualitative and ethnographic approaches. Qualitative data wereanalyzed using ethnographic approaches. The result of research suggests that MLM businesses have undertaken manipulative cooperation politics by establishing both international level direct selling association (WFDSA) and national association (APLI) in response to the MLM business controversy. APLI exploits andmanipulates non-member of APLI. Exploiting and manipulating MLM members through ideology doctrine and marketing plan of MLM business/corporate culture
Alterações hematológicas de cães naturalmente infectados por membros da família Anaplasmataceae diagnosticados pelo esfregaço de sangue periféricoa
Authors: VERONICA JORGE BABO TERRA
Published: March 2017

Canine ehrlichiosis is a very important infectious disease in Brazil, with higher prevalence rates in tropical and subtropical regions due to the distribution of the vector. The aim of this study was to evaluate the hematological alterations of dogs naturally infected with Ehrlichia spp. or Anaplasma platys, diagnosed by the visualization of morulae in mononuclear cells or platelets in blood smears. We have evaluated 909 blood smears of dogs submitted to the Veterinary Hospital, during the period of fourteen months. In infections caused by Ehrlichia spp. the most frequent changes were anemia (74.85%), eosinopenia (62.85%), nuclear deviation of neutrophils to the left (14,85%), lymphopenia (56.57%) and leukopenia (29.71%). On the other hand, in infections suggestive of Anaplasma platys it was observed lymphopenia (51.85%), leukopenia (24.07%) and eosinopenia (44.44%). Among the anemic animals, the most common type of anemia was normocytic normochromic. Thus, eosinopenia, lymphopenia, normocytic normochromic anemia and leukopenia were the most common findings in the studied infections.
Variação regional da perda de calor latente na superfície corporal de ovinos Morada Nova em uma região semiárida
Authors: João Batista Freire de Souza Junior
Published: March 2017

The aim of the present study was to evaluate the latent heat loss in different regions of the body surface of sheep in the semiarid region of Brazil. We used four Morada Nova sheeps between 12 to 18 months old. The animals remained in the shadow of a sheepfold covered with ceramic tiles and ceiling height of 3 meters. We measured the air temperature, relative humidity, wind speed, temperature of the globe, cutaneous evaporation, the surface temperature of the fur of animals and latent heat flux on the cutaneous surface of animals, to perform the calculations. The results of analysis of variance showed that the effect of body region was significant (P = 0.0256). The highest average in loss of latent heat of the cutaneous surface (Es) was measured in the neck (123.54 W m-2), which differed significantly (P
Avaliação de níveis crescentes de guandu sobre as características bromatológicas e qualidade fermentativas da silagem de sorgo
Authors: Lerner Arévalo Pinedo
Published: March 2017

The sorghum plant is one of the most suitable for silage production, with higher yields and production of good quality silage. However, sorghum can have condensed tannins in the whole plant, which for animals, these substances are considered antinutritional factors. Thus, this work aimed to evaluate the chemical composition of sorghum silage with increase addition of Cajanus cajan (pigeon pea). The treatments were: - silage with 100% sorghum, silage with 25% of pigeon pea and sorghum 75%, silage with 50% of pigeon pea and sorghum 50%, silage with 75% pigeon pea and 25% of sorghum and silage with 100% pigeon pea based on fresh matter. The silages were produced in 20 experimental silos tubes (four replicates / treatment). The silos were opened 54 days after ensiling, Chemical composition and silage fermentation parameters indicated that, the addition of pigeon pea promoted significant (P
A incidência do vírus rábico transmitido por quirópteros nas regiões do Alto Araguaia e Sudoeste de Goiás
Authors: Luiz Antonio Silva
Published: March 2017

This study reports the incidence of rabies virus in cattle, horses and bats in the High Araguaia and South west of Goiás, in the period 2000 to 2010. The data were obtained from the files of Goiana Agriculture Defense Agency Laboratory of the Veterinary Diagnosis and Analysis (LABVET), totaling in 502 samples. Samples of the central nervous system of these animals were subjected to direct immunofluorescence and mouse inoculation. It was found positive to the virus in 111 samples of cattle, 8 in horses and no account to Chiropterans. The South West registered the highest number of positive cases for the virus. Most bat species was analyzed Desmodus rotundus. It’s suggested, a intensive and complete study of the biological aspects of bats sent for analysis and also, a further escalation in the number of samples sent, which will contribute to the knowledge of these animals in the epidemiology of rabies.
Avaliação do número de machos e fêmeas nascidos por monta natural e inseminação artificial numa média propriedade leiteira no município de Campo Maior-PI
Authors: GIOTO GHIARONE TERTO E SOUSA
Published: March 2017

The search for technological change in the agricultural sector has led the countries to build strategies that provide prosperity and development in rural areas. In Brazil, technological standards are planned with the aim of bringing the agricultural products of the world quality level. The cattle of milk is one of the most known activities in the context of farming. The adoption and viability of the technique of artificial insemination (AI) require a minimum number of animals in a herd so that there is adequate economic return. The knowledge of the productive potential of animals for milk production and the factors that interfere with the expression of this potential is paramount to be delineated the ultimate goals of this cattle farm. Is consensus among the scientific community and the creators that the technique of AI is an important tool for accelerating genetic evolution of flocks. The study aimed to evaluate the number of births for males and females by natural service (MN) and artificial insemination (AI). The search is a retrospective study conducted by survey data catalogued in a farm located in the municipality of Campo Maior-PI from 1998 to 2009. The data were analysed by mean and standard deviation. In the period were born (42.45%) males of 121 natural service (MN) and 164 (57.55%) of artificial insemination (AI), the birth of females for natural service (MN) was 126 (22.15%) and 443 (77.85%) by artificial insemination (AI); the average number of births for males and females by natural service (MN) and artificial insemination (AI) was 10.08; 13.66; 15 and 32.41 with standard deviation of 11.97; 15.29 and 13.17.17.05; The birth of females by artificial insemination (AI) was higher than the birth of males born by natural service (MN) and artificial insemination (AI). Artificial insemination proved more efficient in reproductive parameters analyzed what will probably have positive reflexes on the productivity of the farm.
PREPARATION AND PHOTOLUMINESCENCE PROPERTIES OF RF-SPUTTERED ZnO FILMS
Authors: Lieu N. T. T. , Canh T. D. , Nghia N. X. , Tarigan K. , Phan T. L.
Published: March 2017

ZnO/Si films were prepared by radio frequency (RF) magnetron sputtering at room temperature. By optimizing the heat treatment conditions, we obtained a good quality film annealed at 700 ºC for longer 60 minutes. This process was monitored carefully by Raman scattering spectroscopy, and X-ray diffraction. The photoluminescence study on this film revealed that only ultraviolet emissions due to donor-acceptor pair (DAP), neutral acceptor-bound exciton (AºX) and donor-bound exciton (DºX) were observed. The intensity and peak position of these emissions depend on the measurement temperature and excitation power density.
THE CORROSION PROTECTION ON STEEL PIPE ST 41 IN WATER PLUMBING ENVIRONMENTAL USING NATRIUM CARBONATE (NA2CO3) AS INHIBITOR
Authors: Arwati I. G. A. , Izzati T. , Arifin Z.
Published: March 2017

This study aimed to analyze the effect of adding to the rate of steel corrosion inhibitor and comparing the rate of corrosion on steel pipes with and without inhibitors.The testing conducted in Puspitek shown that the most optimum inhibitor contained in the addition of 1% due to changes in the price of the original acidity (pH) from 7.30 to 11.80. This shows the increasing of pH occurred sizable value and followed by the declines of potential value (Ecorr) -700.53 mV to -512.39 mV. Thus, the  decreasing accured to the current corrosion value (Icorr) from 2.71 μA/cm2 to 0.31 μA/cm2, while the corrosion rate of carbon steel St 41 decreased most effective after adding 1% Na2CO3 as inhibitor, the corrosion rate is changed from 1.2437 mpy to 0.1427 mpy.
EFFECT OF ANNEALING ON MAGNETIC AND STRUCTURAL PROPERTIES OF THE NANOCRYSTALLINE Fe-Mn-Al ALLOYS
Authors: Tarigan K. , Sebayang D.
Published: March 2017

In this work, the formations of Fe55Mn10Al35 nanocrystalline alloys were made by using mechanical alloying (MA) technique with the milling time of 24 hrs and then annealed at 300, 500, and 700oC. The sizes and the morphology of the particles were checked by using a Scanning Electron Microscope (SEM). The magnetic properties were characterized by using a Vibration Sample Magnetometer (VSM), and it give results both of the magnetic saturation (Ms) and Coercivity (Hc) are decreased respect to annealing temperatures. Last one; the structures were characterized by using an Extended X-ray Absorption Fine Structure (EXAFS) and X-Ray Diffraction (XRD). It give results that the structures were single phase at 24 hrs milled and 300oC annealed, then the structure to be changed at 500 and 700oC. 
BIODIESEL PRODUCTION FROM WASTE COOKING OIL BY USING ULTRASONIC TUBULAR REACTOR
Authors: Agustian E. , Praptijanto A. , Sebayang D. , Rus A. Z. M. , Hasan S.
Published: March 2017

The aim of this research is to find an optimum of synthesis biodiesel from waste cooking oil (WCO) using ultrasonic tubular reactor. The experimental studies explored the variations in reaction time, molar ratio WCO to methanol (MeOH), amount of catalyst, frequency of ultrasonic and output power ultrasonic on the ester contents. Comparisons of type ultrasonic and also mechanical stirring method based on time reaction were investigated. The optimum results of biodiesel process is the reaction time of 5 minute, NaOH catalyst 1%wt of WCO, molar ratio WCO to MeOH of 1:6, frequency ultrasonic of 20 KHz and output power ultrasonic of 650 W. The reaction time reduced 12-24 times compared to both of method and the yield of ester contents was obtained at 96.54%wt.
LIFE EXTENSION TECHNIQUE FOR WELDED STRUCTURE USING HFMI/PIT: A REVIEW ON PAST AND CURRENT RESEARCHES WITH APPLICATIONS
Authors: Manurung Y. H. P. , Mohamed M. A. , Andud D. , Abidin A. Z. , Saidin S. , Kasim K. , Ishak D. P.
Published: March 2017

In this paper, High Frequency Mechanical Impact (HFMI) using Pneumatic Impact Treatment (PIT) which can be applied for new or aging welded structure towards asset integrity will be discussed. The technology HFMI/PIT which falls under post weld treatment process is primarily aimed to enhance fatigue life and to strengthen welded joint. At first, the basic principle on fatigue of welded structure based on the IIW Recommendation will be briefly described. Further, various investigations conducted by prominent research universities or institutions and various industrial applications in European countries will be reviewed and discussed. Lastly, the current research on application of HFMI/PIT carried out under Advanced Manufacturing Technology Excellence Centre (AMTEx) at Faculty of Mechanical Engineering UiTM Shah Alam will be presented. As conclusion, it is stated that HFMI/PIT can be applied for extending the structural life and also for design optimization.
Efecto de la tipografía y presentación de párrafos de textos impresos sobre el aprendizaje a distancia en personas adultas
Authors: Mónge-Nájera Julián , Méndez-Estrada Victor Hugo , Villalobos Rodríguez Alfonso
Published: March 2017

Aunque se ha estudiado el efecto de la presentación gráfica de textos sobre la legibilidad, su efecto sobre el aprendizaje es prácticamente desconocido. Aplicamos un texto control y dos tratamientos (variacio- nes en los párrafos y variaciones en la tipografía) a 169 estudiantes (67% mujeres) elegidos mediante un procedimiento aleatorio dentro de una población de 2692 estudiantes de un curso inicial en la Universidad Estatal a Distancia de San José, Costa Rica, en 2008. La información en los textos era nueva para los estudiantes. Tras 15 días de plazo para estudiar los textos, respondieron a un examen escrito sobre el tema de los textos y llenaron una encuesta ilustrada sobre cuáles presentaciones de párrafo y tipografía les resultaban más agradables al estudiar. Ni la tipografía, ni la presentación de los párrafos, ni el sexo de los estudiantes, tuvieron efecto sobre la nota obtenida en el examen. La encuesta indicó que sí existe una preferencia subjetiva por la letra Arial de 12 puntos, espaciado normal entre letras, espacio sencillo entre renglones, numeración lateral de las páginas, fondo blanco para el texto, títulos con negrilla en lugar de letra corriente, y textos con estas seis características: subtítulos, resumen, ideas clave resaltadas, palabras importantes resaltadas con negrita, espacio para hacer anotaciones a mano e imágenes en color. La tipografía y presentación de párrafos no tuvieron efecto sobre el aprendizaje, pero sí sobre la comodidad al estudiar. Recomendamos que el estudio se repita con estudiantes de otras edades, cursos, universidades e historiales para saber si nuestros resultados son generalizables.
Las asociaciones de desarrollo de la comunidad en Costa Rica durante el decenio de 1970
Authors: Mondol Velásquez Miguel Ángel
Published: March 2017

La Asamblea Legislativa de Costa Rica creó la Dirección Nacional de Desarrollo de la Comunidad (DINADECO) en 1967 para apoyar a las asociaciones de desarrollo de la comunidad , constituidas por vecinos que comparten objetivos de mejoramiento económico y social para su comunidad. Aquí describo y analizo, dentro del contexto nacional, la historia de DINADECO entre 1968 y 1978, periodo en el cual se constituyeron 807 asociaciones y 26 uniones cantonales. Para 1978, el 90% de los distritos, tenía, por lo menos, una asociación. Los resultados económicos de esta decisión estatal, fueron sorprendentes: el valor agregado agropecuario nacional tuvo un crecimiento superior al de los países latinoamericanos tomados en su conjunto. El valor agregado de la producción industrial, también. Y en la industria, el aumento fue todavía mayor y más prolongado. Pero la riqueza producida se distribuyó desigualmente. El 20% de las familias más ricas del campo se hicieron un 11% más ricas entre 1971 y 1977. Pero muchos campesinos perdieron su tierra e ingresaron a alguna de las modalidades del sub-empleo; 125 mil tuvieron que emigrar. Por otra parte, propongo la hipótesis nueva de que hubo múltiples vasos comunicantes y complementarios entre asociaciones y municipalidades en ese periodo. Finalmente, los déficit acumulados por el modelo de crecimiento económico hicieron zozobrar muchas asociaciones de desarrollo en la década de 1970. El efecto de la decisión de la administración Carazo Odio (1978) de trasladar DINADECO a un Ministerio de escaso poder político (Cultura) y reducir su presupuesto, sería un buen tema para una investigación futura.
Efecto de estudiar biología celular con una célula virtual: comparación entre Canadá y Costa Rica, y entre educación presencial y a distancia
Authors: Méndez-Estrada Victor Hugo , Mónge-Najera Julián
Published: March 2017

Cuando se le compara con la educación en los países industrializados, la educación latinoamericana suele parecer anticuada e inferior. Sin embargo, la computación generalizada podría tender a disminuir las diferencias regionales. Para averiguar si el aprendizaje sería diferente cuando un mismo material digital se usaba en Canadá (país industrializado) y Costa Rica (cuya economía se basa en el ecoturismo y la agricultura), usamos Cellule, un material multimedial interactivo con animaciones, texto y locución, para la enseñanza de la biología celular básica. Participaron en total 96 estudiantes y evaluamos su opinión mediante cuestionarios. No encontramos diferencias importantes según el país, o la modalidad de enseñanza (presencial o a distancia). El curso virtual Cellule es un excelente material para la enseñanza de la biología celular básica, tanto en países industrializados como en países latinoamericanos.
Efecto de tomar un curso en línea sobre el aprendizaje de los estudiantes de agroindustria en la Universidad Estatal a Distancia de Costa Rica
Authors: Andrés Carmen
Published: March 2017

El aprendizaje en línea es cada vez más común en todo el mundo y es una herramienta que permite estudiar y trabajar. La Universidad Estatal a Distancia motiva a los estudiantes a aprender a través de este sistema. Agroindustria fue el primer curso en línea que se impartió en la carrera de agronomía. Los contenidos del curso fueron adaptados a esta modalidad. Se estudió el efecto en el aprendizaje al utilizar este método de enseñanza, el rendimiento y la opinión de los estudiantes. La evaluación y el aprendizaje fueron positivos, así que el curso de agroindustria y la utilización de materiales en línea fueron exitosos en esta universidad.
Elicitation effect on cell biomass and production of alkaloids in cell suspension culture of the tropical tree Eurycoma longifolia
Authors: Keng Chan Lai , Wei Ang Sze , Bhatt Arvind
Published: March 2017

Analizamos el efecto de varios “reveladores” en la biomasa celular y la producción de alcaloides en células del árbol asiático Eurycoma longifolia. Las suspensiones celulares fueron preparadas por inoculación 0,5g FW (peso fresco) de células extraídas de suspensiones celulares de primer procesamiento preparadas de callos celulares en medio líquido MSBs. Agregamos quitosan, NaH2PO4, Na2CO3 y polivinilpirrolidona (PVP) como reveladores para aumentar la biomasa celular y la producción de alcaloides. El medio MSBs con 100mg/L chitosan induce un incremento significativo en la biomasa celular mientras que un aumento de quitosan (150mg/L) induce una alta producción de 9-hidroxicanthina-6-uno (0,44%), pero no de 9-metoxicanthina-6-uno. La adición de 2mg/L y 20mg/L NaH2PO4 aumenta la biomasa celular y la producción de alcaloides respectivamente. Sin embargo, la adición de Na2CO3 y polivinilpirrolidona muestran un efecto inhibitorio en el crecimiento celular y en la producción de alcaloides no hay un aumento significativo.
Caracterización de la comunidad vegetal en áreas de bosque nativo y plantaciones de coníferas en la Reserva Forestal Grecia (Alajuela, Costa Rica)
Authors: Maglianesi María Alejandra
Published: March 2017

Se estudió la comunidad vegetal en la Reserva Forestal Grecia (Alajuela, Costa Rica) en áreas de bosque nativo y plantaciones de especies exóticas de coníferas. Se realizaron comparaciones en la composición, riqueza, abundancia y diversidad de especies vegetales a través de un gradiente altitudinal entre los 1700 y los 2300m.s.n.m. en bosque nativo (cada 100m y entre hábitats). El trabajo de campo se realizó en el 2008 y se basó en el desarrollo de 20 transectos en total, con una superficie total de 0.4 ha. Las áreas de bosque nativo presentaron un valor promedio de riqueza (F1=2,73; P=0,116) y abundancia relativa (F1=6,51; P=0,02) mayor con respecto a las plantaciones, en particular aquellas plantaciones más densas, sugiriendo que la luz constituye un factor limitante para el establecimiento de especies autóctonas. Por lo tanto, algunas medidas de manejo como la implementación de estrategias de restauración ecológica enfocadas al reemplazo gradual de especies exóticas por nativas, podría incrementar la diversidad vegetal y con ello la biodiversidad en la Reserva. Además, se identificaron una serie de especies vegetales de características particulares, lo cual revela un alto valor de la Reserva Forestal Grecia para la conservación de estas especies.es
Cambios estacionales en los ovarios de peces siluriformes: comparación de tres especies en un ambiente subtropical de Argentina
Authors: Romero Nélida Marcela , Vera-Mesones Rosa
Published: March 2017

El Orden Siluriformes constituye un grupo diverso y ampliamente distribuido de peces Ostariofísidos, cuya mayor diversidad está en la región tropical y subtropical. Incluye un importante grupo de especies de bajo porte cuya relevancia se relaciona con las redes tróficas de ríos y arroyos de diferentes magnitudes. En este trabajo se analizan los cambios estacionales de ovarios de peces Siluriformes de bajo porte frecuentes en ríos y arroyos del Valle de Lerma, Salta, Argentina. Se realizaron muestreos estacionales desde 1995 hasta 2004, en cuatro ambientes diferentes. Los ejemplares colectados fueron fijados y medidos, las gónadas se extirparon para su procesamiento histológico. Las especies seleccionadas fueron: Corydoras paleatus, Trichomycterus spegazzinii y Heptapterus mustelinus. Se analizaron: valor de condición K, índice gónado-somático, frecuencia ovocitaria, fecundidad, talla mínima de madurez sexual, características macroscópicas y microscópicas de las gónadas en las diferentes estaciones del año, determinándose en cada especie el período de desove. Los cambios histológicos en las diferentes etapas de madurez de las gónadas de estas especies son similares, son desovadoras parciales, la época de desove de T. spegazzinii y H. mustelinus se extendería desde la primavera temprana hasta mediados de verano, C. paleatus desovaría durante todo el año, con picos en verano.
Presencia espacial y temporal de Aramus guarauna (Gruiformes: Aramidae) y de Rostrhamus sociabilis (Accipitriformes: Accipitridae) en la Reserva de la Biósfera Marismas Nacionales, Nayarit, México
Authors: Carmona Roberto , Mendoza Luis Francisco , Molina David , Martínez Paulina , Vargas Jonathan , Cruz Miguel
Published: March 2017

Realizamos visitas mensuales a 12 sitios ubicados en la Reserva de la Biósfera Marismas Nacionales (noviembre 2010 a junio 2011), en cinco de ellos observamos regularmente carraos (Aramus guarauna) y gavilanes caracoleros (Rostrhamus sociabilis) en tres de estos. En las zonas de observación (humedales salobres) abundó el caracol manzana (Pomacea spp.), la presa más importante de ambas especies. Para el carrao se obtuvo 493 registros en 31 eventos de observación, los sitios de mayor importancia fueron Las Cañadas y La Batanga (en conjunto 64% de los registros); en marzo y abril observamos parvadas de hasta 80 individuos, en probable relación con la época de estiaje. Del gavilán obtuvimos 109 registros, de individuos solitarios; los sitios más importantes para esta especie fueron Zoquipan y Mexcaltitán (96%). Dada la presencia de los caracoles manzana, Marismas Nacionales es utilizada regularmente por ambas especies y éstas pueden continuar expandiendo su intervalo de distribución a lo largo del Pacífico mexicano, al menos hasta el norte de Sinaloa, donde la falta de agua dulce y vegetación acuática dificultará el establecimiento de poblaciones de caracoles. PALABRAS CLAVEAramus guarauna, Rostrhamus sociabilis, distribución espacial, distribución temporal, Marismas Nacionales, Nayarit, Pomacea spp
Performance of selected macroinvertebrate-based biotic indices for rivers draining the Merendon Mountains region of Honduras
Authors: O’Callaghan Paul , Kelly-Quinn Mary
Published: March 2017

Cusuco National Park, a cloud forest park situated in the Merendon Mountains region of Honduras, is home to considerable biodiversity with a very high degree of endemism. Like many other cloud forest parks in Central America, it was declared a protected area not because of its biodiversity, but mainly because of its function in protecting river water quality in the headwaters draining the park. Illegal and authorised forest clearance for agricultural activity such as coffee production and pasture for animals and diffuse inputs from settlements are expected to affect aquatic macroinvertebrate communities and the water quality of the rivers in the park. There is however very limited water quality monitoring, mainly because biological indices such as those in use in Europe and the United States among others have not been developed in Honduras. A research project based on macroinvertebrates was initiated in 2009 to develop a water quality index for the area. Sampling was undertaken between June and August 2009 and set out to sample minimally disturbed upper catchments of reference rivers. This paper evaluates the performance of several  indices. A version of the ASPT based on the BMWP calibrated for Costa Rica (BMWP(CR)) performed best.     KEY WORDSBiomonitoring, Honduras, macroinvertebrates, neotropics, upland stream, water quality
Sucesión de un bosque tropical seco en la Isla San Lucas, Puntarenas, Costa Rica
Authors: Vargas G. German , Hidalgo-Mora Jairo E.
Published: March 2017

El bosque tropical seco (BTS) es actualmente el ecosistema más degradado y fragmentado de todos los tipos de bosque de tierras bajas tropicales; lo que ha generado la necesidad de un manejo adecuado de los últimos remanentes. Evaluamos la sucesión y el grado de regeneración utilizando como indicador la diversidad vegetal de un BTS en el Refugio Nacional de Vida Silvestre Isla San Lucas. Se establecieron 13 parcelas y en cada una se midió el diámetro a la altura del pecho (DAP, 1,30m) de los árboles, su altura; y la cobertura del dosel. Posteriormente se midió el estado de regeneración del ecosistema mediante árboles juveniles (DAP<10cm y altura entre 1 y 3m). Se calculó el área basal, la biomasa aérea, densidad relativa, frecuencia relativa, dominancia relativa y el índice de valor de importancia (IVi), tanto a nivel familia como para cada una de las especies de árboles e individuos jóvenes. El ecosistema presentó una cobertura vegetal de 66,11% con una alta variación entre sitios ±20,22%, donde se encontraron 25 especies para ambas clases etarias. Para la altura se encontró que un 52% de los árboles medidos se encontraban entre los 5,87 y 9,90m. La distribución de clases diamétricas en forma de J invertida es un indicativo de un bosque en proceso de regeneración, esto porque hay una mayor densidad de tallos delgados. En el grupo de árboles la familia Fabaceae presentó el IVi más alto, mientras que Sapindaceae en el grupo de los latizales. La similitud entre especies fue de 52%, indicando un cambio de un grupo a otro. La diversidad entre árboles y latizales es similar, con una tendencia mayor hacia los latizales, lo cual es una característica típica de bosques secundarios jóvenes.PALABRAS CLAVEBosque tropical seco, sucesión natural, diversidad vegetal, índice de valor de importancia, bosque secundario
Toxic dinoflagellates (Dinoflagellata) the coast of Chiapas , Mexico , Eastern Pacific center
Authors: Maciel-Baltazar Ebodio
Published: March 2017

In this paper are given to know toxic species with public health importance, samples were obtained during 2010-2012 in the coast of Chiapas, México, by net (20 μm mesh) in vertical hauls (up to 15 m), fixed with Lugol’s solution and studied by light microscope bright field, Twenty-four species were documented to be present in the study área: Gymnodinium (1); Alexandrium (5); Pyrodinium (1); Phalacroma (2); Dinophysis (4);Prorocentrum (4); Karenia (4); Protoceratium (1); Gonyaulax (1); Lingulodinium (1), It was found corresponding with 64-89% of the species from coastal waters of México.
Water quality of an Ecuadorian Andean stream with the use of aquatic macroinvertebrates.
Authors: Liñero Arana Ildefonso , Balarezzo Víctor H. , Eraso Héctor , Pacheco Francisco , Ramos Carolina E , Muzo Ruth G , Calva Carla J
Published: March 2017

Ecuador is crossed by a network of rivers that originate mainly in the high Andean reliefs and pour into two basins: Amazon and Pacific. Many suffer from severe human impact. The main objective of the present study was to assess water quality of Mojarrero stream using biotic indices (BMWP/Col. and Shannon-Wiener index) as a tool to evaluate ecosystem health. During June, August and October 2014, bottom samples were taken at three stations. Each month and season three replicates of benthic aquatic invertebrates were taken on sandy-stony bottoms with a 0,3 mm mesh “D-net”. The fauna was represented by eleven orders and 29 families. The most abundant order was Coleoptera, representing 42,70% of total collected organisms, followed by Diptera (19,01%) and Ephemeroptera (11,38%). The most abundant family was Elmidae, with 568 individuals, (37,37% of total organisms), followed by Chironomidae (11,38%) and Baetidae (7,24%). Shannon diversity values ranged between 0,98 bits/ind. (June, EST. 2) and 2,23 bits/ind. (October, Est 1). The BMWP/Col. index values indicate that the river has a good environmental health on the high and low sections. The median section has some pollution, particularly during August and October.
Papeles invertidos: arañas depredadoras de gusanos de terciopelo neotropicales (Epiperipatus spp.; Onychophora: Peripatidae).
Authors: Franco Rosmery , Monge-Nájera Julián
Published: March 2017

Los gusanos de terciopelo (Onychophora) son antiguos depredadores de origen cámbrico que ocasionalmente consumen arañas cténidas. Aquí informamos el caso contrario: arañas (Ctenus spp.) alimentándose de gusanos onicóforos (Epiperipatus spp.) en Colombia y Costa Rica. Aparentemente las presas no lograron expulsar su red defensiva y la eficacia del veneno de araña sugiere que los nervios y músculos de los onicóforos son bioquímicamente equivalentes a los de los insectos.
Densidad del estrato herbáceo y su relación con luminosidad, pH y cantidad de hojarasca en la Reserva Biológica Alberto Manuel Brenes, San Ramón, Costa Rica
Authors: Madrigal Luis Alejandro , Vargas Verónica
Published: March 2017

La composición biótica de muchos ecosistemas está haciendo alterada rápidamente, por lo que hay una necesidad creciente de entender los procesos ecológicos y mantener su biodiversidad. Se midió la densidad del estrato herbáceo de 30 cuadrículas (50 cm2) establecidas en tres transeptos (25m x 2m), en la Reserva Biológica Alberto Manuel Brenes, San Ramón, Costa Rica. Encontramos que los factores significativos en la densidad herbácea son el pH y la cantidad de hojarasca.
AN ANALYSIS OF THE IMPLEMENTATION OF PROBLEM BASED LEARNING IN LEARNING ENGLISH AT THE XI GRADE SCIENCE CLASS OF SMA NEGERI 1 SINGARAJA IN THE ACADEMIC YEAR 2015/2016
Authors: Apriliadewi P.A.R.
Published: March 2017

This research aimed to describe the implementation of problem based learning science in learning English at the XI grade science class of SMA Negeri 1 Singaraja. The subjects of this research were an English teacher and 32 students of class XI MIA 6 in SMA N 1 Singaraja. Research methods used were observation, interview and questionnaire. The results of this research show that: (1) the implementation of problem based learning in learning English in XI MIA 6 class of SMA N 1 Singaraja has been implemented based on the phases of this model; (2)The problems faced by the English teacher during the implementation of problem based learning are  the teacher is difficult to manage the learning time, determine the problem which is related to students’ characteristics, and cannot check all of the students’ work because of the big number of the students’; (3)The main problem faced by the students during the implementation of this model was they cannot improve in collaborative learning in solving the problem. However, the students give a positive response to the implementation of problem based learning in their class.
THE EFFECT OF DICTOGLOSS STRATEGY ON THE LISTENING COMPETENCY OF THE TENTH GRADE STUDENTS AT SMA NEGERI 1 SUKASADA IN ACADEMIC YEAR 2016/2017
Authors: Suprianti G.A.P. , Pratama I Putu Mega
Published: March 2017

This study aimed at investigating whether or not there was any significant effect on students’ listening competency who were taught by dictogloss strategy and those who were taught by conventional strategy. The population of this study was the tenth grade students in SMA N 1 Sukasada. Two classes were taken as samples in this study using cluster random sampling technique. They were assigned as experimental group and control group by lottery. To obtain the required data, the two groups were given different treatments. The experimental group was taught by using dictogloss strategy, meanwhile the control group was taught by using conventional strategy (cloze listening strategy). To collect the data the instruments used in this study were the teaching scenario and post-test in the form of listening test. The obtained data were then analyzed descriptively and inferentially. The result of inferential statistics showed that the t-observed exceeded the t-critical value. Thus, the null hypothesis was rejected, which means there was significant effect on students’ listening competency who were taught by dictogloss strategy and those who were taught by conventional strategy.
Drain versus non drain in thyroid surgery
Authors: Mohialdeen Fadhil Ahmed , Salih Abdul-Wahid M , Gubari Mohammed IM , Hama-law Soran Ameen
Published: March 2017

The use of a suction drain in thyroid surgery is common practice in order to avoid hematomas or seromas. The aim of this study was to determine the efficacy of inserting a routine drainage tube after thyroid surgery. In this retrospective study, 102 patients who underwent either a total thyroidectomy for thyroid disorders were assigned to either the drained or the non-drained groups. The length of hospital stays, postoperative pain, patient comfortability and complications were retrieved. Both groups were homogeneous according to age, gender, type of procedure performed, histopathological diagnosis residency and marital status. No significant difference was found between the two groups in post- operative complications, but the length of hospital stay was significantly reduced in non-drained group (p<0.0001), and drained group needed one more dose of analgesics compared to non-drained group to alleviate the post-operative pain.Our findings, suggesting that the use of drain for thyroid surgery cannot lower the incidence of complications. Furthermore, the use of drains may increase length of hospital stay, postoperative-pain,and the need of analgesic and contribute to the discomfort of the patients. Hence, the routine insertion of drains after total thyroidectomy for benign disorders might not be necessary.
Murallas, de Gabriel Bernal Granados. Una lectura a la luz de la tradición mexicana de la nouvelle sobre la memoria y el autodescubrimiento
Authors: Gutiérrez Juan Tomás Martínez
Published: March 2017

En este artículo se propone que Murallas (2015) de Gabriel Bernal Granados puede ser leída como una novela corta o nouvelle. Así considerada se enmarcaría dentro de una tradición de las letras mexicanas caracterizada por llevar a la ficción la rememoración del tránsito de la infancia a la vida adulta, las primeras exploraciones de la sexualidad y el autodescubrimiento de los protagonistas. Esta tradición incluye obras como Elsinore: un cuaderno, de Salvador Elizondo, Las batallas en el desierto, de José Emilio Pacheco y Unión, de Juan García Ponce, por ejemplo. Asimismo, esta aproximación explora algunos elementos que constituyen la poética de Murallas; se analizan principalmente tópicos como unidad, dispersión y fisura.