bluuebunny/crossref_metadata_2025 huggingface dataset:
Guest Editorial: The Looming Market for Abandonment and Decommissioning
Authors: Jardon Michael
Published: March 2017

Guest editorial

The market for abandonment and decommissioning has undoubtedly grown over the past 5 years, as the boom of the 1970s and 1980s makes way for the first tranche of major decommissioning projects. From the smaller plug-and-abandonment campaigns in the Gulf of Mexico to the mighty Brent field in the UK North Sea, we have reached a milestone in our industry that feels alien to many of us.

Having spent the majority of my 25-year career focused on exploration and appraisal, this has not been lost on me. A large proportion of those years were committed to the complex challenges associated with high-production land wells in the Middle East, offshore, deep water, as well as subsea projects in the Gulf of Mexico, Brazil, Asia, and Australia. However, as we continue to optimize recovery from mature fields, it has opened my eyes to the prospect of decommissioning from a challenge that was “on the horizon” to one that is quite literally on our doorstep.

Government legislation has played a large part in this refocus, as recent changes drive specific technical and time requirements. For example, the US Bureau of Safety and Environmental Enforcement (BSEE) says that, under its Idle Iron Program, wells or platforms no longer in use must be decom-missioned within 5 years. As of 2015, this amounted to 535 eligible platforms and rising. While Europe’s legislation is different, Oil and Gas UK’s recent Decommissioning Insight 2016 report estimated that over the next decade, 186 projects are forecast for decommissioning, including 1,800 wells. To deliver this in a safe and economic way, we need to accept and embrace decommissioning as a serious industry challenge.

Many people still perceive or talk about decommissioning in a negative way, as if it marks the immediate death of our industry. Setting aside the fact we are still making new discoveries, it has taken us many decades to explore for oil and will take many more to abandon our wells and decommission infrastructure. A study from the late 1990s estimated the cost of decommissioning the world’s 6,500 offshore platforms at between USD 29–40 billion over 30 years (Pittard 1997). However, this now seems a huge underestimation, given that the UK alone is forecasting a cost of nearly GBP  18 billion/USD 22 billion over 10 years (Oil and Gas UK 2016). Either way, the figures are extremely compelling.
Technology Update: Retrofitting MPD Systems to Deepwater Rigs Aids Drilling, Efficiency, and Process Safety
Authors: Toralde Julmar Shaun Sadicon
Published: March 2017

Technology Update

The unique properties of deepwater formations pose significant challenges to the capabilities of conventional drilling rigs. By retrofitting rigs with automated drilling systems, including managed-pressure drilling (MPD) equipment, operators and contractors in global deepwater basins can optimize efficiency and economics while maintaining the level of safety that the industry and regulatory community have mandated for this high-stakes arena.

MPD, an adaptive drilling process that actively controls annular pressure throughout the wellbore, is increasingly being integrated into the risers of existing deepwater drilling vessels (Fig.  1). It is the cornerstone of an automated well-control strategy that augments and enhances standard well-control protocols.

The technique provides distinct drillability, efficiency, and process safety benefits in deepwater environments. It addresses the higher level of priority that the industry has placed on process safety, which largely involves the ability to accurately and actively monitor and control operations while drilling. 

Long used in land and shallow-water drilling, MPD-ready rigs are proving their value in deepwater operations by delivering a reliable level of automation and process control when the risk of a well-control incident is highest. Fluctuations in wellbore pressure often create drilling hazards that result in lost circulation, kicks, and other problems that can significantly increase rig time and cost, or lead to catastrophic well-control incidents.

An automated MPD system installed onto a deepwater semisubmersible rig or drillship can effectively monitor and maintain the annular hydraulic pressure profile by applying common MPD variants, such as constant bottomhole pressure (CBHP) and pressurized mud cap drilling (PMCD).

The ability to continuously monitor various wellbore parameters—particularly those related to downhole pressure—while drilling and making connections also enhances personnel preparedness by serving as an extra set of eyes to supplement those of less-experienced drillers.

While expanding the drilling envelope and monitoring wellbore pressure profiles, an MPD system that provides automated advanced flow detection, including early kick detection, also reduces the risks of human intervention by mitigating the possibility of gas in the riser.
How To Develop a Well-Specific Capping-Stack Blowout Contingency Plan
Authors: Wilson Adam
Published: March 2017

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 181393, “How To Develop a Well-Specific Blowout Contingency Plan That Covers Engineering Analysis of the Deployment, Installation, and Soft Shut-In of a Subsea Capping Operation,” by Ray T. Oskarsen, SPE, Morten H. Emilsen, SPE, and Amir S. Paknejad, Add Energy; Mike Cargol, Trendsetter Engineering; and Kwee Choong See, SPE, Shell International Exploration and Production, prepared for the 2016 SPE Annual Technical Conference and Exhibition, Dubai, 26–28 September. The paper has not been peer reviewed.

The planning process for developing a well-specific subsea-capping contingency plan involves assessing the feasibility of deploying a capping stack from a floating vessel, determining the weight and stability of the capping stack to overcome the force of the blowout jet, and performing dynamic-flow simulations of closing the capping stack outlets without loss of well integrity. This process not only assesses the feasibility, complexity, and risk exposure of the capping operation but also may justify further planning, studies, or expenditure.

Introduction

Blowout-kill techniques can be classified as either surface-intervention or relief-well methods. Relief wells aim to kill a blowout from the bottom by injecting fluid into the wellbore until the influx of formation fluid is stopped and the well is static when pumping stops. In many cases, a relief well will be the safest intervention and have the highest likelihood of success, and often it is considered the last line of defense against a blowout. Surface interventions are kill attempts aimed at controlling the discharge at the wellhead or at the fluid-exit point. An example is to install a capping stack on top of the wellhead and close its openings, which can be gate valves, chokes, or rams.

Blowout Contingency Planning. Blow-out contingency plans ensure that people understand and can manage risks, thus ensuring safe and sustainable operations at all times.

All blowouts are inherently different; thus, it would be both impractical and impossible to attempt to cover every possible blowout scenario in a contingency plan. For source-control planning, an operator should, at a minimum, address a worst credible scenario to demonstrate how the well will be brought under control. This scenario may be different from the worst-case discharge, which is used to estimate spill potential and necessary resources for containment and cleanup. As an example, if there is uncertainty about the gas/oil ratio (GOR), a low-case GOR may cause more oil spill, while a high-case GOR may make source control more challenging.
Technology Focus: Offshore Facilities (February 2017)
Authors: Elkins Mark
Published: March 2017

Technology Focus

Welcome to the Offshore Facilities feature in this month’s JPT.  I had the plea-sure of screening 207 papers submitted to SPE in this field during the past year to come up with the three papers selected for this issue that cover elements of offshore facilities design and inspection.

The first paper describes a design case study for split-process floating liquefied natural gas, in which the primary production and gas-treatment functions are provided on a host platform while liquefaction occurs on separate vessels that serve also for storage and trans-port. Splitting the services results in advantages that include facilitating standardization of the liquefaction design and eliminating the need for liquefied-natural-gas-offloading systems designed for open-water conditions.

The next paper describes a risk-based approach for application of passive fire protection (PFP) on an offshore structure. Principles of this unified risk-based approach for accidental loadings and its application to fire-response analysis and PFP are explained, and the method is compared against the conventional approach.

The third paper covers work performed by the Hull Inspection Techniques and Strategy joint-industry project to develop new floating production, storage, and offloading vessel hull-inspection methods that minimize or eliminate diving. This has been achieved by conducting many of the inspections from inside the hull, using advanced methods to inspect critical isolation valves and marine piping, and inspecting the hull appendages with miniature remotely operated vehicles. The alternative method delivers improved inspection data as well as significant reductions in cost and people on board and minimal weather/sea-state downtime.

I hope you enjoy reading these papers.

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

IPTC 18373 Adapting the Caspian Factor for the Installation of Petronas’ First Gravity-Based Structure by Khairil Raezwan Rashdi, Petronas, et al.

OTC 26481 Development of a Novel Hybrid AUV System for Pipeline Inspection in Gulf of Thailand by Phakhachon Hoonsuwan, PTTEP, et al.

OTC 27068 Fuel Efficiency on Floating Production Systems by Jos Bronneberg, SBM Offshore USA
Passive-Fire-Protection Optimization in Offshore Topside Structures
Authors: Wilson Adam
Published: March 2017

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 26579, “Passive-Fire-Protection Optimization in Offshore Topside Structures,” by Ali Sari, Genesis Oil and Gas; Ekkirala Ramana, Technip Malaysia; and Sepehr Dara and Umid Azimov, Genesis Oil and Gas, prepared for the 2016 Offshore Technology Conference Asia, Kuala Lumpur, 22–25 March. The paper has not been peer reviewed. Copyright 2016 Offshore Technology Conference. Reproduced by permission.

Applying sufficient passive fire protection (PFP) on topside structural-steel members is critical. Simplified and conservative approaches are available to estimate the extent and amount of PFP necessary. The main concern with simplified approaches is that they can lead to overapplication of the PFP, resulting in substantial increase in topside weight. These methods also may result in underestimation of the required amount of PFP, which can compromise structural integrity. This paper presents a risk-based approach for PFP-scheme development.

Introduction

The structural-integrity assessment and fire-response analysis of offshore plat-forms in fire focus on providing safe escape routes for personnel for a specified period of time and minimizing the probability of damage and fracture in primary structural steel, hydrocarbon-equipment supports, secondary steel along the primary escape routes, and pressurized hydrocarbon pipes and vessels.

In order to achieve this, PFP is used extensively in offshore topside structures. A PFP material is a good thermal insulator, and application of PFP on steel components of the topside structure results in a delay of the heat transfer to the protected members. Therefore, material degradation and thermal expansion are postponed in protected members. Consequently, structural integrity of the escape routes and safety of hydrocarbon pipes and vessels can be retained for a specified period of time, depending on the rating of the PFP material (properties and thickness). On the other hand, if PFP is used excessively, a considerable amount of cost will be imposed related to PFP material, installation, inspection, and maintenance and a considerable amount of dead load will be added to the structure. Therefore, investigations on the optimal application (e.g., choosing the right places—members, joints, vessels, and pipes—along with the right material in the appropriate thickness) in offshore platforms can result in cost-effective use of PFP while still achieving the purpose of the PFP application.

Existing PFP-Optimization Approaches

Global Fire (Individual-Member Failure). The global fire analysis method for identifying PFP application on a top-side structure requires analysis of the whole structure when entirely exposed to the most severe fire loading. The PFP scheme is then developed on the basis of the structure’s response. This method is very conservative and results in an excessive amount of required PFP to resist the fire loading.
Integrated Approach To Managing Formation Damage in Waterflooding
Authors: Carpenter Chris
Published: March 2017

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 174174, “Integrated Approach To Managing Formation Damage in Waterflooding,” by Sergey Aristov, Paul van den Hoek, and Eddie Pun, Shell, prepared for the 2015 SPE European Formation Damage Conference, Budapest, Hungary, 3–5 June. The paper has not been peer reviewed.

Understanding of formation damage is a key theme in a waterflood project. An integrated multidisciplinary approach is required to determine an optimal design and strategy. An operator has developed a suite of tools to tackle these issues and help in adequate design and optimization of waterfloods.

Introduction

Many waterfloods in the operating phase do not perform as expected. Often this is because of well-injectivity issues where the required water quality for the injected water is either not properly defined (i.e., by the subsurface disciplines) or not properly managed (i.e., at the surface facilities). A rapid decline in well injectivity can result when injecting under matrix conditions, and a loss in reservoir containment caused by out-of-zone injection (OOZI) or a short-circuiting injector and producer can occur when injecting under fractured conditions, all negatively affecting reservoir sweep.

Subsurface and Subsurface-Modeling Work Flows

To determine an optimal waterflooding concept, it is important for the integrated work flow that the outcome of the sub-surface assessment be a range of technically feasible scenarios. These scenarios should incorporate the ranges in subsurface uncertainties combined with sub-surface concept options. The objective for the subsurface work flow is to define for each of these scenarios the production profile for the field, injection volume, quality of injected water, number of injection wells, subsurface targets, risk, and mitigations.

The subsurface work flow is illustrated in Fig. 1 of the compete paper. The following main steps are identified:

Identification of potential water sources. All available water sources need to be identified, and a screening should be performed by assessing the compatibility of the injected water with the clays in the reservoir (i.e., risk of clay swelling).

Injection targets for field development. On the basis of the expected reservoir performance for waterflooding in a field development, the targets for the total water-injection volume for the (full) field should be defined.
Cover Crop Options and Mixes for Upper Midwest Corn–Soybean Systems
Authors: Appelgate Seth R. , Lenssen Andrew W. , Wiedenhoeft Mary H. , Kaspar Thomas C.
Published: March 2017

Core Ideas

Cover crop mixtures did not provide benefits beyond cover crop monocultures.

Cover crops did not influence soil temperature, soil P or K concentrations, or corn yield.

Cover crops did not influence weed density or weed community in subsequent corn.

The use of cover crops can decrease soil erosion, weed density, and nitrate leaching while improving soil quality. We investigated nine cover crops, winter rye (Secale cereale L.), winter triticale (× Triticosecale Wittm. ex A. Camus), two winter canola (Brassica napus L.), winter camelina [Camelina sativa (L.) Crantz], spring barley (Hordeum vulgare L.), spring oat (Avena sativa L.), turnip (B. rapa L.), and hairy vetch (Vicia villosa Roth), as sole crops and selected binary and trinary mixtures and their influences on subsequent corn (Zea mays L.) productivity. A control treatment of no cover crop was included. Cover crops were no‐till drilled immediately after soybean [Glycine max (L.) Merr] harvest. The study was a randomized complete block conducted in five environments over 2013–2014 and 2014–2015. Across environments, rye and rye mixtures produced the greatest spring aboveground biomass (758 kg ha−1), C, and N accumulation, had some of the lowest spring soil nitrate concentrations, and generally produced the lowest corn leaf chlorophyll. Rye accounted for more than 79% of spring aboveground biomass accumulation in rye mixtures. Triticale and camelina monoculture produced approximately 50% less biomass than rye or mixtures with rye. Cover crops in monoculture and mixtures did not influence surface soil temperature, soil P or K concentrations, weed density, weed community, or corn yield. Cover crops had limited influence on volumetric soil water content. Cover crop mixtures had no advantages over monocultures except for increasing fall stand density. Turnip and vetch had limited winter survival while barley, oat, and canola winterkilled.
Similarities among Test Sites Based on the Performance of Advanced Breeding Lines in the Great Plains Hard Winter Wheat Region
Authors: Graybosch Robert A.
Published: March 2017

USDA‐ARS coordinated regional wheat (Triticum aestivum L.) breeding trials examine agronomic performance and adaptation over a wider geographic range than single breeding programs can achieve. The trials provide an evaluation of experimental breeding lines in alternate test sites that are environmentally similar or dissimilar to the program of origin. Data from USDA‐ARS Hard Winter Wheat Regional Nurseries grown in 1987 to 2014 were used to identify similarities among Great Plains test sites. Mean correlations of entry grain yields across locations and years were used in principal factor analyses to cluster them into production zones. The procedures used were identical to those of a previously published analysis using test data from 1959 to 1989. Five factors explained 67% of the variance in the correlation matrix among Southern Regional Performance Nursery (SRPN) locations. The analysis divided the SRPN into four major Great Plains production zones, designated Southeast, Northwest, Southwest and Northeast. The remaining minor production zone consisted of only two central South Dakota locations, both outside the typical target area and selection site of SRPN entries. In the Northern Regional Performance Nursery (NRPN), five production zones were established, with location separation predominantly resulting from east–west differences in performance. The SRPN and NRPN wheat production zones closely follow previously described ecological zones of adaptation of native Great Plains plant species. Wheat breeding programs and growers may continue to use the production zones established via the USDA‐ARS coordinated winter wheat regional nurseries to target and select germplasm for crossing and for production.
Impacts of Cattle Grazing of Corn Residues on Soil Properties after 16 Years
Authors: Rakkar Manbir K. , Blanco-Canqui Humberto , Drijber Rhae A. , Drewnoski Mary E. , MacDonald James C. , Klopfenstein Terry
Published: March 2017

Core Ideas:

Spring cattle grazing of corn residues slightly increased the risk of soil compaction.

Fall cattle grazing of corn residues had no negative effect on soil properties.

Increased soil compaction caused by grazing was small and did not reduce crop yield.

Corn (Zea mays L.) residue grazing can be an important component of crop–livestock systems, but its long‐term impacts on soil properties are not well understood. Some producers are concerned that residue grazing can induce soil compaction and reduce crop yields. We assessed the 16‐yr cumulative effect of cattle grazing of corn residues on soil compaction, structural quality, soil C, fertility, and microbial communities and studied their correlations with corn and soybean [Glycine max (L.) Merr.] yield in a sprinkler‐irrigated no‐till corn–soybean system on a Tomek silt loam in eastern Nebraska. Three treatments were studied: (i) fall grazing [4.4–6.2 animal unit‐months (AUM) ha–1], (ii) spring grazing (9.3–13.0 AUM ha–1), and (iii) control (no grazing). Cattle grazing did not affect bulk density, wet soil aggregate stability, particulate organic matter, soil organic C, and nutrients except Ca and S. Spring grazing increased the cone index (soil compaction parameter) by 1.3 to 3.4 times relative to the control, but fall grazing had no effect. The increase in soil compaction caused by spring grazing was below the threshold limit (≤2 MPa) and did not reduce corn and soybean yields. Although grazing had a positive effect on the biomass of most microbial groups, the results were not significant, except for actinomycetes, which increased with residue grazing (p = 0.06). Overall, long‐term corn residue grazing had little or no effect on soil properties and the small changes did not affect crop yields.
Methylene blue removal using a low-cost activated carbon adsorbent from tobacco stems: kinetic and equilibrium studies
Authors: Mudyawabikwa Bellington , Mungondori Henry H. , Tichagwa Lilian , Katwire David M.
Published: March 2017

The aim of this study was to prepare activated carbon from tobacco stalks using microwave heating. The prepared activated carbon was applied as an adsorbent in methylene blue (MB) removal from water. The optimum conditions for activated carbon preparation were a radiation power of 280 W for a period of 6 minutes after the impregnation of the precursor material with 30% ZnCl2 for 24 hours. The activated carbon yield and iodine number were 49.43% and 1,264.51 mg/g respectively. The activated carbon also had a point of zero charge of 5.81 with an adsorption capacity of 123.45 mg/g for MB. The optimum conditions for MB adsorption were a pH of 6.5 with an adsorbent dosage of 0.2 g/50 mL at 25 °C. The MB adsorption kinetics followed the pseudo second order kinetic model with the intra-particle diffusion model suggesting a two-step adsorption mechanism. The adsorption data also fitted well within the Langmuir adsorption isotherm model. Tobacco stalks can successfully be turned into an economically important product.
Seasonal variation of microbial community for the treatment of tail water in constructed wetland
Authors: Liang Kang , Dai Yanran , Wang Feihua , Liang Wei
Published: March 2017

Effects of seasons and hydraulic loading rates (HLR) on the treatment performance and the response of the microbial community of vertical flow constructed wetland treating tail water were investigated. The seasonal treatment performance was evaluated at four HLR of 125, 250, 375 and 500 mm/d, respectively. The microbial community was detected by MiSeq Illumina platform at HLR 125 and 375 mm/d. The wetland showed significantly higher chemical oxygen demand (COD) and total nitrogen (TN), total phosphorus (TP) at HLR 125 mm/d, compared with other HLR. Overall removal efficiency was 61.47%, 71.40% and 76.31% for COD, TN and TP, respectively, while no significant differences for COD, TN and TP removal were found at HLR of 250, 375 and 500 mm/d. The best removal efficiency for COD and TN was achieved in summer and autumn, while the best TP removal was achieved in winter. Nitrification bacteria (Nitrosomonas and Nitrospira) were significantly higher in HLR 125 mm/d, whereas sequences associated with denitrification had no significant difference at the two HLR. The results can partially explain the significantly higher NH4+-N removal in HLR 125 mm/d and relatively low nitrogen performance in winter.
BOOK REVIEW. HOW TO READ LITERATURE BY TERRY EAGLETON REVIEW-THE MACRO ASPECTS OF LITERARY CRITICISM
Authors: Gailea Ginanjar
Published: March 2017

Terry Eagleton, the author of How to Read Literature, is a well-known British literary theorist, critic and public intellectual. He is a professor of English Literature at Lancaster University. Among his publications, Literary Theory: An Introduction (1983) is still the best one till nowadays. In How to Read Literature, Eagleton attempts to deal with the challenge of literary criticism at present. It is because students of literature often percept a literary work as what it says. The aspect of ‘literariness’ which is a work’s aesthetic form is not taken into account. A literary work, then, is a mere of writing that shares information to the readers as though a newspaper, text book or manual of computer does. Whereas, focusing on literary forms and directing our sensitivity to language (these are items mostly discussed in this book) can uncover a theoretical and political question of text (ix). What is meant by literary forms are all elements building a body of work such as “tone, mood, pace, genre, syntax, grammar, texture, rhythm, narrative structure, punctuation and ambiguity (2).”
HIGH RESOLUTION IMAGING OF BORON DISTRIBUTION ON DIAMOND FILM USING ENERGY FILTERED TEM
Authors: Dimyati A. , Purwanto S. , Iskandar R.
Published: March 2017

The main difficulty in investigation of thin film systems is the lack of capability to get detail information of the material in nano level due to the low resolution of conventional imaging techniques such as SEM, SIMS etc. In this work Electron Spectroscopy Imaging (ESI) in energy filtered transmission electron microscope (EFTEM) was used to produce a real image of  boron distribution in a diamond film deposited on (111) Si by chemical vapor deposition. The result revealed the layer consists of 1.3 µm thick diamond structured carbon film adjacent to Si substrate and 120 nm amorph carbon layer on top most surface. Boron atoms were distributed uniformly in both layer, however slight higher concentration in the second layer is observed. There was obviously no grain boundary enrichment of Boron atoms observed.
DEVELOPMENT OF INTEGRATED GAS INSTRUMENTATION SYSTEM IN DIRECT REDUCTION PLANT
Authors: Adriansyah A. , Rahman F.
Published: March 2017

Direct reduction is the removal of oxygen from iron without melting process. In direct reduction process, the presence of mixture gas in accordance levels largely determines the performance of the iron produced. Therefore, it needs gas sensors system which has high accuracy and reliability in this process. Unfortunately, there are some things that cause decreasing in the accuracy and reliability of the gas sensor in this process. This paper aims to offer a system that can preserve the accuracy and reliability of the gas measurement system called as Integrated Gas Instrumentation System. The system tends to integrate gas sensor component using Specific Gravity (SG) with other components, such as water trap, filter regulator and monitor gas flow rate. The values of Specific Gravity Meter based on process that display in DCS system are compared with lab results for three type of experiments. Based on experiment results it can be said that the proposed system is able to improve the accuracy and reliability of direct reduction process.
El mercado del trabajo sexual femenino en la ciudad de San José, Costa Rica
Authors: Rojas Campos Rosberly , Mónge-Nájera Julián , Ramírez Sánchez Iris Amalia , Morales Bonilla Roxana
Published: March 2017

Aunque el trabajo sexual corresponde a una transacción comercial y es parte de la economía, socialmente se oculta y su flujo de capital no se menciona en los informes económicos. En 2008 entrevistamos a 78 mujeres que lo realizan en la ciudad de San José, capital de Costa Rica. Hubo tres grupos: mujeres que trabajan en la zona aledaña al Mercado Borbón y Mercado Central, con tarifa entre US$3 y US$8 por hora y edades de 26 a 81 años; trabajadoras de dos salas de masajes de San Juan de Tibás (US$18 a US$72 por hora y 18 a 33 años) y trabajadoras independientes (US$100 la hora; 19 a 38 años). Las entrevistas se hicieron con base en un cuestionario, se pagó a las entrevistadas su tiempo y los datos se analizaron con el programa estadístico SPSS. Según el grupo, entre la mitad y una mayoría opinó que el trabajo sexual es, para las mujeres, una forma lícita de mantener a sus familias y para los hombres, un escape que reduce la violencia sexual. Las mujeres no tienen jefe y deciden independientemente sobre horario y lugar de trabajo, y sobre cuáles prácticas realizan, rechazando clientes si no hay acuerdo. Pocas han sufrido violencia o enfermedades de transmisión sexual como resultado de su trabajo sexual. La mayoría no tienen compañero fijo o esposo. El cliente preferido es amable, de edad madura y se atiende siempre con la misma mujer. El cliente indeseable es agresivo, tacaño, sucio y/o drogado. Los clientes son principalmente casados y con 35-45 años de edad. Los servi- cios solicitados son diversos, pero predominan el sexo oral y el coito con la mujer boca arriba. La tarifa es definida por el grupo de pertenencia (mercado, sala o independiente) y no por la edad. Aunque las ganancias varían ampliamente, superan en mucho lo que estas mujeres ganarían en empleos adecuados a su baja escolaridad. Hay poca cultura de ahorro, pero las trabajadoras tienen total decisión sobre en qué gastan sus ganancias, haciéndolo fundamentalmente en el mantenimiento de sus hijos y otros familiares. Debido a las pocas mujeres que realizan tra- bajo sexual allí, este trabajo representa un porcentaje bajo dentro de la economía de la ciudad de San José.
La escolaridad en trabajadoras sexuales de la ciudad de San José, Costa Rica, al iniciarse el siglo XXI
Authors: Ramírez Sánchez Iris Amalia , Mónge-Nájera Julián , Rojas Campos Rosberly , Morales Bonilla Roxana
Published: March 2017

San José es la ciudad capital de Costa Rica, pequeño país centroamericano caracterizado por un mayor nivel educacional, mayor ingreso per capita y mayor nivel de vida que el resto de los países de la región. Un estudio hecho en 1975 indicó que las trabajadoras sexuales de la ciudad eran mujeres que habían elegido el trabajo sexual porque en él ganaban mucho más que en las demás opciones laborales que tenían, dado su nivel de escolaridad, en general limitado a la escuela primaria, y que cerca de la mitad no deseaban cambiar de actividad. Con el fin de con- ocer si la situación había cambiado casi cuatro décadas después, en 2008 entrevistamos a 78 mujeres que realizan trabajo sexual en la ciudad, con tarifas entre US$3 y US$100 la hora y edades 18 y 81 años. Las entrevistas se hicieron con base en un cuestionario; se pagó a las entrevistadas su tiempo y los datos se analizaron con el programa estadístico SPSS. La mayoría de estas trabajadoras son costarricenses de origen urbano, pocas tienen estudios más allá de la escuela primaria, y consideran que su principal logro en la vida fueron los años escolares aprobados pese a la poca ayuda que recibían en este campo de sus familias. Un tercio declaró haber tenido una niñez agradable, y la mayoría dicen no hallar conflicto entre su trabajo y las creencias religiosas, pues lo hacen para mantener a sus hijos, ya que son madres solteras. Creen además que su trabajo disminuye la violencia sexual. La mayoría usa el preservativo como protección y cree en la visión patriarcal de que la mujer cría a la familia y el hombre provee los recursos. Las universidades podrían ofrecerles a estas mujeres apoyo para concluir sus estudios, apoyando con becas y asesoría y haciendo más estudios para separar el mito de la realidad, por ejemplo con historias de vida, una técnica que permitiría dar a las trabajadoras sexuales una voz desde la concepción de sus propios mundos y del ambiente en que se desarrollan.
Deserción estudiantil en posgrados semipresenciales de la Universidad Estatal a Distancia (UNED), Costa Rica: ¿Deserción o retraso?
Authors: Barrientos Zaidett , Umaña Roy
Published: March 2017

La deserción estudiantil para posgrados semipresenciales ha sido poco estudiada. Se han desarrollado varias categorías teóricas para justificar la deserción: psicológica, académica personal, sociológica, económica, organizacional, oferta y demanda de la educación superior y del mercado, e interacción. Mediante encuestas, entrevistas y datos institucionales se analiza el caso de una maestría académica semipresencial. Se encontró que el problema debe repensarse como un retraso en la graduación (68%), pues la deserción calculada según el reglamento académico es del 87%, pero según la intención expresada por los estudiantes es de 19%, de los cuales el 6% corresponde a traslados a otras instituciones, además, en promedio tardan 16 meses en presentar el examen de candidatura cuando reglamentariamente se espera que lo hagan en 6 meses. Por lo tanto, aplicando las estrategias adecuadas es posible bajar la tasa de deserción a alrededor del 15%. La deserción (según intención de los estudiantes) se relaciona negativamente con la opinión que tengan de: 1) grado de concordancia entre el perfil de salida profesional y las necesidades del mercado laboral, 2) capacidad docente de los profesores y 3) nivel de relación entre el trabajo que desempeña el estudiante y la maestría. Ninguna de las categorías teóricas existentes explica plenamente los resultados, por lo que se considera que los factores determinantes en la deserción pueden variar según la situación sociocultural e institucional de cada caso. Para disminuir la deserción se recomienda mejorar: 1) la capacidad docente, 2) el diseño curricular, 3) la selección de estudiantes, 4) el contenido del primer bloque de materias, 5) el ingreso de estudiantes de grado de la misma institución y 7) la inducción a un sistema semipresencial. Para disminuir el retraso en la graduación se recomienda: 1) reestructurar los cursos de seminario de tesis, 2) fortalecer la investigación en los cursos, 3) dar mas acompañamiento en el proyecto de investigación, 4) ajustar los tiempos reglamentarios y 5) seleccionar estudiantes que quieren una maestría académica.
Simulación computacional de grupos de investigación en la Universidad Estatal a Distancia de Costa Rica
Authors: Segura-Castillo Andrés
Published: March 2017

La modelación y simulación multiagente en el contexto de las ciencias sociales se ha convertido en un método de análisis complementario para investigadores de estas disciplinas, ya que facultan la creación de modelos computacionales que simulan las interacciones humanas en ambientes virtuales, con el fin de explorar la aparición de patrones de comportamiento emergente no observables a simple vista en el fenómeno real. En este estudio se presenta un sistema multiagente creado para modelar y simular la dinámica de los grupos de investigación de la Universidad Estatal a Distancia. Los resultados de un primer escenario indican que la proporción inicial de recursos disponibles en el sistema no tiene una relación causal directa con el coeficiente de agrupamiento, métrica que mide la tendencia que tienen los investigadores a formar grupos. Se plantea que debe reestructurarse el concepto de recursos en el modelo, con el fin de incluir no solo variables estrictamente económicas, sino también de infraestructura y disponibilidad de equipo. Por otra parte, en un segundo escenario fue posible establecer que el aumento en la cifra de investigadores es un factor que disminuye el coeficiente de agrupamiento, ya que el sistema trata de balancear los costos y beneficios de mantener una cantidad dada de los mismos. La investigación insiste que el modelo computacional creado no es un producto acabado, por el contrario, debe afinarse para incluir otras variables y aproximarse en mayor medida al fenómeno real.
Current Status and Conservation of the Scarlet Macaw (Ara macao) in the Osa Conservation Area (ACOSA), Costa Rica
Authors: Dear Fiona , Vaughan Christopher , Morales Polanco Adrián
Published: March 2017

Se estudió el estado y conservación de la lapa roja (Ara macao) en el Área de Conservación de Osa (ACOSA) entre octubre y diciembre del 2005. El proyecto se llevó a cabo realizando una entrevista estructurada, con 22 preguntas, a 105 adultos locales y desarrollando un taller con 18 participantes de la región, que resultó en un plan estratégico. Entre los resultados mas sobresalientes, se encontró que: a) la población de lapa roja se extiende en toda la Península de Osa y hacia el norte hasta Playa Piñuelas; b) no fue posible estimar el número de individuos en la población, pero puede existir entre 800-1200 individuos y los habitantes locales consideran que esta aumentando; c) las lapas no se concentran en sitios para pernoctar; d) se alimentan de al menos 59 especies de plantas (semilla y fruta) de las cuales tres especies exóticas se consideran importantes: el almendro de playa (Terminalia catappa), la teca (Tectona grandis) y la melina (Gmelina arborea); e) anidan entre diciembre y mayo en huecos de árboles de unas 28 especies, siendo la ceiba (Ceiba pentandra) y el ajo (Caryocar costarricense) las más utilizadas; f ) existe extracción de pichones (aprox. 25-50 por año) por parte de laperos, siendo una persona la principal responsable de dicha extracción ya que colecta al menos 25 pichones anualmente; g) existen tres programas de liberación de lapas rojas, los cuales se encuentran ubicados en el área de Golfito y Pavones y h) el plan estratégico formulado contempla proyectos de investigación, monitoreo, conservación, extensión y mercadeo de la especie; lo anterior incluye estudios sobre dinámica poblacional, hábitat, ecología de reproducción, genética, extracción de pichones y programas de conservación.
La gestión del saneamiento ambiental en asentamientos humanos en Costa Rica: los casos de dos comunidades urbanas y una rural
Authors: Chamizo García Horacio Alejandro
Published: March 2017

El concepto de saneamiento ambiental debe superar la noción tecnocrática dominante para situarse en su dimensión sociopolítica, desde el modelo de gestión de la Nueva Gobernanza Democrática. Los casos seleccionados son dos asentamientos periurbanos y uno rural, con problemas de saneamiento ambiental. Se estudiaron las representaciones sociales y sus posibles efectos en el comportamiento de los actores durante la gestión. Las condiciones del contexto ambiental son importantes en la formación de las ideas en torno al problema y sus posibles soluciones. Los conceptos, valores, y actitudes dominantes han sido asignados fundamentalmente desde las organizaciones del Estado durante la interacción en las redes de actores. Tales valores contribuyen a la simplificación y fragmentación de la realidad, dificultando la atención de la complejidad de los problemas.
Sector eléctrico de Costa Rica: aplicación del Análisis Estructural para definir variables claves de una reforma neoclásica
Authors: Jiménez Gómez Roberto
Published: March 2017

Presento una aplicación de la Técnica de Prospectiva y el Análisis Estructural, el cual se emplea para definir las variables claves que inciden en mayor medida en el sistema eléctrico en el marco de un proceso de reforma en Costa Rica. Permite identificar la situación presente y futura de las variables, los actores que pueden incidir en ellas, y generar escenarios posibles de reforma del sector eléctrico. Se establecieron las variables más importantes, según el modelo actual y las que tendrían más relevancia en caso de que se lleve a cabo una reforma de orientación neoclásica. Dentro de las variables que tendrían una mayor relevancia en un sistema eléctrico reformado están: Mercado mayorista nacional, Grado de disociación de las organizaciones del sector eléctrico, Competencia en la generación de electricidad, Influencia política en las decisiones, Potencial de generación eléctrica de Costa Rica.
Atropello de vertebrados en una carretera secundaria en Costa Rica
Authors: Rojas Chacón Esteban
Published: March 2017

Las carreteras han sido uno de los cambios antropológicos más notables dentro de los paisajes naturales. Sus efectos son mucho más visibles y fuertes en poblaciones animales, las cuales sufren pérdida de conectividad, disminución del ámbito de distribución y hábitat; y la disminución de individuos por muertes en carretera. De estos tres efectos, la muerte en carretera es el más visible y fácil de medir. En este estudio se tomó un registro tres veces por semana de todos los atropellos para un segmento de 800metros de una carretera secundaria, durante un periodo de dos meses de 2010; en el Valle Central de Costa Rica. Nueve vertebrados fueron atropellados en un período donde la cantidad de vehículos fue menor, en comparación con tres atropellos cuando el tráfico fue mayor, generando una correlación negativa entre el número de muertes y el número de vehículos (r= –0,545). El grupo taxonómico más afectado fue Bufonidae, con cinco atropellos.
Calidad microbiológica de la materia prima y el producto final del ceviche de tilapia y de camarón expendidos en el Área Metropolitana de San José, Costa Rica
Authors: Arias Echandi María Laura , Chaves Ulate Carolina
Published: March 2017

El ceviche es un platillo formulado a base de pescado de agua salada o dulce, o mariscos frescos y diversos aliños. Su elaboración acarrea no solo la flora normal y adquirida de la materia prima a utilizar, sino que también la flora que se agregue durante su procesamiento y a partir de ingredientes adicionales. Además, es un producto que se consume marinado, representando un riego para la salud pública. El objetivo de este trabajo fue determinar la calidad microbiológica del ceviche de tilapia y del ceviche de camarón que se vende en el Área Metropolitana de San José, Costa Rica, así como de la materia prima utilizada en su respectiva elaboración. Para tal efecto, se analizaron 25 muestras de ceviche de tilapia y 27 de camarón, analizando igual número de muestras de materia prima. De la misma manera, se analizó el comportamiento de las poblaciones de algunos microorganismos de deterioro a partir de 25 muestras de ceviche de camarón y 25 muestras de ceviche de tilapia durante su almacenaje a 4oC. A pesar de la contaminación bacteriológica presente en la materia prima, y de que el ceviche es un producto que incluye mucha manipulación, existe una disminución importante en las cargas bacterianas en el producto final, especialmente en lo que respecta a recuento total de aerobios psicrófilo y coliformes totales, no así los coliformes fecales. Se aisló Escherichia coli a partir de 15% de ceviches de tilapia y 4% de los ceviches de camarón, 3 cepas de Listeria monocytogenes a partir de tilapia, 1 a partir de camarón, y 3 cepas de V. parahaermolyticus a partir de camarón y 2 a partir de su ceviche. No se aisló Salmonella spp. En cuanto a los ceviches almacenados a 4oC por una semana, cabe destacar que el pH mostró una tendencia hacia la estabilidad o de aumento muy ligero. De la misma manera, la concentración de microorganismos de deterioro sufrió pocas variaciones, no obstante, llama la atención el bajo número de Pseudomonas spp. presentes en los ceviches de tilapia.PALABRAS CLAVECeviche, tilapia, camarón, deterioro.
A biodiverse housing market in hermit crabs: proposal for a new biodiversity index
Authors: Laidre Mark E. , Vermeij Geerat J.
Published: March 2017

Cuantificar la variación de la biodiversidad es un objetivo importantede la biología. Sin embargo, debido a que tales inventarios, en especialpara la biodiversidad marina, son costosos, difíciles y consumenmucho tiempo, hay un gran valor en indicadores simples que permitandeterminar la biodiversidad de una región determinada de maneraeficiente. Hicimos un inventario de las conchas usadas como casasmóviles terrestres por los cangrejos ermitaños (Coenobita compressus)en la Península de Osa, Costa Rica, un “punto álgido” de biodiversidad.Se registraron 41 especies, el mayor número registrado en cualquierpoblación de cangrejos ermitaños. Proponemos que la “diversidad delmercado de vivienda” en los cangrejos ermitaños puede proporcionarun índice de biodiversidad ecosistémica conveniente, lo que podríafacilitar las comparaciones entre sitios.ABSTRACTQuantifying variation in biodiversity is an important goal of biology.However, because inventorying biodiversity, especially marinebiodiversity, is costly, difficult, and time consuming, there is great valuein simple metrics that can reliably indicate a given region’s biodiversityand that can be efficiently gathered. We inventoried shells used asportable houses by terrestrial hermit crabs (Coenobita compressus) inOsa Peninsula, Costa Rica, a biodiversity hotspot. Forty-one species wererecorded, the largest number registered for any hermit crab population.We propose that housing market diversity in hermit crabs might providea convenient biodiversity index of ecosystems, potentially facilitatingcomparisons across different sites.
First report for the Neotropics of predation by the waterscorpion Ranatra (Hemiptera: Nepidae) on a member of Gerromorpha (Hemiptera)
Authors: Herrera Federico
Published: March 2017

The water scorpion Ranatra pittieri was observed preying on an adult of the water strider Eurygerris flavolineatus in a closed laboratory system. This is the first report for the Neotropics of the predation by a member of the infraorder Nepomorpha on a species of Gerromorpha.KEYWORDWaterscorpions, Heteroptera, Gerridae, Nepomorpha, Costa Rica, Central America
Prevalence, intensity and abundance of endoparasites in Oreochromis niloticus and Tilapia zilli (Pisces: Cichlidae) from Asa Dam, Ilorin, Nigeria
Authors: Amaechi C. Ebube
Published: March 2017

Disease is an important factor in fisheries, affecting both wild and cultured species. Using standard parasitological techniques we determined the prevalence, mean intensity and abundance of endoparasites from 250 specimens of two cichlids, Oreochromis niloticus and Tilapia zilli from Asa dam, Ilorin, North Central Nigeria between February and August, 2013. We found two digenetic trematode parasites:Euclinostomium heterostomum and Clinostomum tilapiae. The highest prevalence was recorded in O. niloticus (35,9%) infested by C.tilapiae, while the highest mean intensity was recorded in T. zilli. There was no relationship (p >0,05) between parasite burden and fish size(length and weight). Male fish were more heavily infected than females.The overall health status of both fish species remained unaffected. Thehigh rate of pollution noticed in the study area might be favoring parasite load. Therefore, pollution control and regular surveillance of the water body are advocated.
A new species of Hemibrycon (Characiformes: Characidae), a freshwater fish from the Sierra Nevada of Santa Marta, Caribbean drainage, Colombia
Authors: García-Alzate Carlos A. , Román Valencia César , Taphorn Donald C.
Published: March 2017

Hemibrycon is a group of freshwater characid fish species first recognized by Günther (1864) as a subgenus of Tetragonopterus, and now included in the subfamily Stevardiinae. There are 21 speciesrecorded from the rivers of Colombia, but only one species, H.santamartae, has been reported previously in drainages of the Sierra Nevada de Santa Marta. Hemibrycon sierraensis n. sp. is described fromthe Río Gaira, Caribbean coastal drainage. It is distinguished from all congeners by having in life a bright red adipose fin (vs. hyaline or transparent)that turns dark brown in specimens preserved in alcohol. It differs from Hemibrycon beni, H. boquiae, H. brevispini, H. colombianus, H. mikrostiktos, H. metae, H. microformaa, H. palomae and H. rafaelense in having a vertically elongate humeral spot that extends 3-4 longitudinal scale series below the lateral line. It differs from H. divisorensis, H. pautensis and H. santamartae by having the last dorsal-fin ray unbranched; and from H. pautensis by the number of scale series between the lateralline and the pelvic-fin insertions. It differs from H. divisorensis in the number of unbranched anal-fin rays, and the number of teeth on the dentary and maxilla. It differs from H. santamartae in the number of supraneurals, caudal peduncle depth, head length and orbital diameter.