bluuebunny/crossref_metadata_2025 huggingface dataset:
Methodology for In-Well DTS Verifications in SAGD Wells
Authors: Hiscock B. , Hinrichs L. , Banack B. M. , Rapati B.
Published: May 2015

In steam assisted gravity drainage (SAGD), temperature instrumentation is widely used to understand steam placement across openhole liners in producer and injector wells. The accuracy of temperature readings is crucial when monitoring wellbore integrity and optimizing production. While distributed temperature sensing (DTS) on fiber-optic cables has been widely used in temperature monitoring, challenges consistently exist regarding accuracy.

Several trials over a 2-year period were completed to quantify the accuracy of DTS systems. Each trial employed different operating conditions and instrumentation:

Case Study 1: Dual-laser DTS and thermocouples were permanently deployed in a newly drilled SAGD producer. The well was heated from geothermal to 240°C. Newly deployed thermocouples were compared against newly deployed fiber-optic cables. Case Study 2: Dual-laser DTS temperature measurements were compared across a 1 dB point loss at a maximum optical budget of 13 dB. Case Study 3: Dual-laser DTS vs. single-laser DTS vs. new thermocouples comparisons were made. Case Study 4: Thermocouples and dual-laser DTS for a mid-life SAGD injector and producer were compared for accuracy after two years of operation. Case Study 5: An independent temperature log containing dual-laser DTS was used to quantify the thermocouple temperature discrepancy on a SAGD producer in operation for 7 years.

The results of these case studies allowed Devon to determine several important learnings, as well as a troubleshooting methodology for evaluating DTS accuracy. When properly installed and calibrated, dual-laser systems are accurate up to ±2°C over the full range of SAGD operating temperatures for stable operating conditions. During the trial period, DTS was shown to maintain accuracy for 2 years.

When comparing the accuracy of temperature systems, it is recommended to compare against other known metrics during falloffs. New thermocouples are still considered the most accurate measurement; however, legacy thermocouples are susceptible to drift. Independent temperature logs have proven to be a valuable tool for assessing legacy instrumentation accuracy for thermocouples and DTS.
Design, Testing, and Field Performance of Steam-Injection Flow-Control Devices for Use in SAGD Oil Recovery
Authors: McChesney Ryan , Felten Frederic , Hobbs Scott , Edlebeck John
Published: May 2015

To promote efficient recovery of bitumen hydrocarbons using the steam assisted gravity drainage (SAGD) process, it is vital that steam be used effectively because steam generation constitutes one of the largest operational expenses during the SAGD process. To optimize this process, steam-injection flow-control devices (FCDs) have been developed. These devices are designed to enhance the operator's ability to distribute steam along the wellbore and to cease steam injection at a particular injection point if necessary, as the steam chamber matures. This paper discusses the design and capabilities of FCDs.

The project initiated with a design requirement of two core components— the axial distribution of steam exiting the device and a device to incorporate a sliding sleeve mechanism. The basis for FCD design decisions was developed initially by reviewing worst-case operating conditions FCDs could encounter and then using this information as the operating envelope criteria that the design should meet. SAGD completion tools are required to endure everything from temperature fluctuations and corrosive formation fluids to erosive wet steam and severe wellbore trajectories. To design a tool that would survive the erosive effects of varying steam quality, the critical velocities and erosive mechanisms were defined. API RP 14E provides a conservative basis to determine the maximum allowable fluid velocity in a given system, but several studies have sought to push the boundaries of acceptable fluid velocities. The most conservative nozzle exit velocities were used to limit risks to casing. The risks caused by high velocities in the nozzle inside/inner diameter (ID) to the injection tool were mitigated through the use of computational fluid dynamics (CFD) analyses and material selection/treatment.

Because of the high temperatures under which SAGD operates, consideration of mechanical property degradation and possible deformation had to be considered, specifically to the collet of the sliding sleeve. To prevent diminishing performance during the operational lifetime, FCDs that use sliding sleeves with collet mechanisms require a robust design that recognizes and addresses maximum stress loads and limits plastic deformation at peak temperatures. The testing of the sliding sleeve was conducted throughout a wide range of temperatures where the forces to shift the sleeve were monitored and compared to previous finite elements analyses (FEA) for compliance.

ISO 14998 Annex D provided the basis for function testing of the FCD (i.e., cycling the sleeve and pressure testing at temperature). All pressure and function testing was performed at or above the operating temperature, and pressure and results were qualified to ISO 14998 V1. Field performance is discussed in the paper.
Detailed History Matching of a SAGD Well Pair Using Discretized Wellbore Modeling
Authors: Nguyen K. N. , Doan L. T. , Kato K.
Published: May 2015

Circulation of steam during the start-up of a well pair is required for the SAGD process where there is limited fluid mobility, as it helps establish communication for flow between the injector and producer well. The majority of the modeling encountered to date for the circulation period either assumed a source/sink constraint, used a horizontal discretized wellbore model with sand face coupling, or used a pseudo-steady state wellbore flow model only. The above methodologies do not take into account 1) the heat transfers and pressure behavior among the different tubing strings, 2) the change in conditions from sand face to wellhead, and 3) the fluid interaction between the wellbore and reservoir.

Using a thermally-coupled wellbore-reservoir simulator, a discretized wellbore model was constructed to allow a detailed history matching for the circulation period of the M-well pair at the Hangingstone Demo pilot. The history-matched circulation period helped better understand the effects of hydraulics, heat transfers between tubing strings and the impact of fluid losses on reservoir heating. This knowledge will help Japan Canada Oil Sands Limited (JACOS) design the operating philosophy for the Hangingstone Expansion wells. The paper will discuss how the matching was achieved along with the observations made.
SAGD Liner Evaluation and Liner Test Design for JACOS Hangingstone SAGD Development
Authors: Spronk E. M. , Doan L. T. , Matsuno Y. , Harschnitz B.
Published: May 2015

JACOS’ Hangingstone Demonstration Project has been in operation since 1999. The company has used the 10,000 bbl/D facility as a foundation for learning and refining SAGD processes and operations. The 24 operational well pairs, with 15 years of production has provided valuable insight into the performance of different liner completion types and operational control mechanisms. Data from the Demo project has provided the basis for a liner test strategy and liner design for application at JACOS’ Phase 1 Hangingstone Expansion project. First steam is expected in late 2016.

All of the 24 operating well pairs at the Demo project have concentric tubular designs, but varying liner completion types. One well pair is completed with MeshRiteTM, 13 well pairs with wire wrap screens and 10 well pairs are completed with slotted liners of varying slot sizes. With a relatively strong surveillance program, the flow distribution (inflow), subcool control, hydraulics and operability for each of the well pairs were carefully analyzed. The performance of wells with MeshRite, wire wrap screen and slotted liners will be presented. The analysis provided insight into what was successful in the field and provided a strong basis for the test design.

As part of the expansion project, field performance data from the six phases of the Demo project, coupled with particle size analysis, flow testing and thermal performance analysis, guided JACOS to select slotted liners for all injector wells. For the producers, 27 wellbores were completed with wire wrap screens and five wellbores with MeshRite liners, for a total of 32 well pairs. This comprehensive study incorporated field learnings, operational successes, and a comparison between the flow test observations and field observations. Finite element analysis and specialized drilling mud contributed to liner installation success for the Hangingstone Expansion.
Well Integrity Evaluation Using Distributed Temperature Sensing (DTS) on an Operating SAGD Injector Well Influenced by Neighboring Steam Chambers
Authors: Thompson Scott , Bello Alejandro , Medina Max , Greig Thomas
Published: May 2015

Temperature fall-off logs are routinely performed on a number of operating wells at Statoil's Leismer field to monitor well integrity. So far, all wells have demonstrated normal temperatures in formations overlying the steam chamber, less than steam temperatures, and with fall-offs according to typical heat conduction. However, one injector well did not fall-off as expected after a 24 hour shut-in; instead showed temperatures exceeding 200°C in formations above the steam chamber. An investigation was launched and a multidisciplinary team evaluated possible causes for the high temperatures.

A review of 4D seismic data showed that a neighbouring steam chamber was intersecting the wellbore. This led to the hypothesis that the high temperatures were the result of wellbore heating from the neighbouring steam chamber, and a follow-up, extended temperature fall-off log confirmed the hypothesis. The extended logging period confirmed that temperatures outside casing did fall-off, albeit at a slower rate than other wells, due to the heating effect of the neighbouring steam chamber. The temperature log measurements indicate that heat from an intersecting steam chamber can cause a counter-intuitive segregation of steam and water in the wellbore, with condensed liquid water held above steam in the upper section of the well. This case study highlights strategies for interpreting downhole temperature anomalies using temperature logs and 4D seismic, and also the benefits of a well integrity investigation with strong cross-discipline collaboration.
Numerical Assessment of the Maximum Operating Pressure for Anisotropic Caprock in SAGD Projects
Authors: Rahmati Ehsan , Nouri Alireza , Fattahpour Vahidoddin , Trivedi Japan
Published: May 2015

This paper investigates the effect of anisotropic behavior of caprock shales on the caprock failure pressure in SAGD projects. Shales and mudstones exhibit strong anisotropy at the micro and macro scales. However, the anisotropic behavior has been neglected in the existing published works on this subject.

In this research project, a coupled hydro-thermo-mechanical model was developed for the assessment of caprock integrity in thermal operations. A transversely isotropic constitutive model in the elastic range was combined with an anisotropic failure criterion to capture the intrinsic anisotropy of the cap shale. The coupled tool was validated against field data and employed in a study to determine the effect of shale anisotropic behavior on the pressure associated with caprock breach.

Results display the effect of shale anisotropy on caprock response in terms of deformations, stresses and failure pressure. The assumption of isotropic shale behavior in caprock integrity assessment for a case study resulted in the overestimation of the failure pressure by about 10%.

Existing numerical models for evaluating the integrity of caprocks during thermal operations employ isotropic constitutive laws. These models are believed to be deficient in capturing strongly anisotropic response of shales and mudstones. The research described in this paper incorporated elasto-plastic shale anisotropy in the caprock failure analysis model for the first time. The paper demonstrates the importance of capturing shale anisotropy in the accurate prediction of caprock breach pressure in SAGD projects.
A case study on a quasi-market mechanism for water resources allocation using laboratory experiments: the South-to-North Water Transfer Project, China
Authors: Yu Zhang , Qingshan Yang , Donghui Lv
Published: May 2015

The chosen water management mechanism will directly or indirectly determine the success or failure of the South-to-North Water Transfer Project. Due to the importance and complexity of the project and based on national conditions and the water situation, it is necessary to adopt a quasi-market mechanism. Using the advanced experience in China and abroad for reference, this study takes the central route of the project as an example and conducts experiments by undergraduates in the laboratory. Under the simplified experimental environment, three basic rules of a quasi-market mechanism are contained and integrated: the combination of governmental macro-control with a market mechanism; the combination of water-supply management with water-demand management; and the combination of routine management with emergency management. By observing the decision-making behaviour of the experimental participants, researchers constantly changed experimental conditions to simulate the real water market realistically; finally, researchers drew conclusions based on the repeated experiments.
Spatial analysis of rural drinking water supply in China
Authors: Li Hongxing , Zhang Qi , Li Weiwei , Luo Qing , Liu Kaitai , Tao Yong
Published: May 2015

A spatial autocorrelation analysis method was employed to process the spatial change of rural water supply over the past 19 years in the People's Republic of China. Statistical analyses indicate great achievements in rural water supply construction. Two main indices describing rural drinking water supply status, the Rural Popularization Rate of Tap Water and the Rural Popularization Rate of Water Improvement Beneficiaries, were found to be spatially auto-correlated. The Global Moran's I of the latter decreased generally, and local spatial autocorrelation analysis showed that the regional gap of rural water supply infrastructure is declining. The main factors affecting the spatial pattern of rural water supply were analyzed through the mean centre method. Our research shows that the spatial pattern of economic development and government investment has had a decisive role in the formation and evolution of rural water supply.
Human resources capacity in Ghana's water, sanitation and hygiene sector: analysis of capacity gaps and policy implications
Authors: Oduro-Kwarteng S. , Monney I. , Braimah I.
Published: May 2015

Adequate human resources (HR) capacity in the water and sanitation sector plays a pivotal role in improving and sustaining access to potable water and improved sanitation. This study highlights the HR capacity and gaps in Ghana's water, sanitation and hygiene (WASH) sector. It is based on data collected from five public sector organisations, six non-governmental organisations (NGOs), 14 private sector institutions and 12 training institutions. The results indicate that the proportion of technical HR was high (75%) in water service delivery, while technical personnel in the sanitation sub-sector was low (2%), leading to low sanitation coverage and ineffective sanitation service delivery. The female proportion ranged from 16 to 44% (average of 22%). There was a shortage of technical personnel in the public WASH sector due to unattractive working conditions, attrition and lack of qualified graduates to fill vacant positions. Average annual graduates' supply from non-technical programmes to the WASH sector is five times more than that from technical programmes. There was a lack of commitment to implement policies on developing adequate HR capacity in the WASH sector due to weak institutional arrangement. There is the need to develop policies on HR career progression and capacity building programmes as well as gender-sensitive recruitment policies for the WASH sector.
Non-revenue water and cost recovery in urban India: the case of Bangalore
Authors: Mukherjee Maitreyee , Chindarkar Namrata , Grönwall Jenny
Published: May 2015

This paper examines the issue of non-revenue water (NRW) in urban India, taking the city of Bangalore as a case study. Using empirical evidence from a survey conducted among 601 low-income households in Bangalore, we investigate the major sources of NRW for water utilities and propose policy recommendations based on the analysis. Our key finding is that public stand posts and public wells, which supply free water, are a non-trivial source of NRW. In addition, we find that revenue generation from metered tap connections is sub-optimal. Further, we observe potential revenue being shifted away from the public water utilities toward private providers, as several households pay for water obtained from neighbours, tankers, or other private sources. Drawing upon our findings, we propose a new tariff structure for urban water utilities to consider. We also review the implementation of pre-payment metering for public stand posts in other developing countries and its feasibility in Bangalore.
Theoretical Method of Strain Rate for RC Beam with Flexible Supports Under Blast Loading
Authors: Chen Wanxiang , Jiang Meng , Guo Zhikun , Liang Wenguang
Published: May 2015

Strain rate is a vital factor for the design of a RC (Reinforced Concrete) member under blast loading. At present,
it is not scientific and cut down the believability to assume the strain rate is a constant or to take the loading rate instead
of the strain rate. In this paper, an analytical model of RC beams with flexible supports is presented, in which the
elasticity, damping, and lumped mass of flexible support are taken into account. Theoretical method of strain rate for RC
beam with flexible supports under blast loading is developed based on Euler-Bernoulli beams. It is indicated that the
maximal values of strain rate are increased as the blast impulses and the overpressures increased, but the loading rates
have not obvious influences on the strain rates. The maximal values and the vibration frequencies of strain rate are increased
as support stiffness increased. The maximal values of strain rate are decreased as support damping increased, and
the attenuation values of strain rate are accelerated. Calculations show that it will result in an overestimation of DIF (Dynamic
Increase Factor) to take the loading rate instead of the strain rate.
A System for Distributed Minting and Management of Persistent Identifiers
Authors: Bolikowski Åukasz , NowiÅ„ski Aleksander , Sylwestrzak Wojtek
Published: May 2015

Minting persistent identifiers and managing their metadata is typically governed by a single organization. Such a single point of failure poses a risk to longevity and long-term preservation of identifiers. In this paper we address the risk by proposing a radically different approach, in which minting and management of persistent identifiers is distributed, and the integrity of the distributed system is guaranteed by public-key cryptography. We describe the general architecture of the system, analyse its robustness and discuss potential deployment scenarios.
APIs and Researchers: The Emperor's New Clothes?
Authors: Edmond Jennifer , Garnett Vicky
Published: May 2015

As part of the Europeana Cloud (eCloud) project, Trinity College Dublin investigated best practice in the use of web services, such as APIs, for accessing large data sets from cultural heritage collections. This research looked into the provision and use of APIs, and moreover, whether or not more customised programmatic access to datasets is what researchers want or need. In order to understand whether current patterns of API usage reflect a skills gap on the part of researchers or a mismatch of tool to purpose, we looked not only at the creators and developer/users of APIs, but also at humanists already re-using big data; approaches in cultural heritage institutions and other research infrastructures to bring API use to non-technical audiences; and the kinds of training and other support services available or emerging within the data-intensive humanities research lifecycle. We conducted both desk research and a series of 11 interviews with figures working as researchers, developers or data providers, including figures from both the API development and the data usage communities. This research, conducted under the eCloud project and supported by the European Commissionâ€™s ICT Policy and Support Programme (Grant number 325091), was begun in March 2014 and is now in its concluding validation stage. The results of the research are not yet finalised, but the contribution is already emerging of this work to the debate about APIs being either the way forward for digital cultural heritage collections, or the Emperorâ€™s New Clothes (or maybe a bit of both).
YesWorkflow: A User-Oriented, Language-Independent Tool for Recovering Workflow Information from Scripts
Authors: McPhillips Timothy , Song Tianhong , Kolisnik Tyler , Aulenbach Steve , Belhajjame Khalid , Bocinsky R. Kyle , Cao Yang , Cheney James , Chirigati Fernando , Dey Saumen , Freire Juliana , Jones Christopher , Hanken James , Kintigh Keith W. , Kohler Timothy A. , Koop David , Macklin James A. , Missier Paolo , Schildhauer Mark , Schwalm Christopher , Wei Yaxing , Bieda Mark , LudÃ¤scher Bertram
Published: May 2015

Scientific workflow management systems offer features for composing complex computational pipelines from modular building blocks, executing the resulting automated workflows, and recording the provenance of data products resulting from workflow runs. Despite the advantages such features provide, many automated workflows continue to be implemented and executed outside of scientific workflow systems due to the convenience and familiarity of scripting languages (such as Perl, Python, R, and MATLAB), and to the high productivity many scientists experience when using these languages. YesWorkflow is a set of software tools that aim to provide such users of scripting languages with many of the benefits of scientific workflow systems. YesWorkflow requires neither the use of a workflow engine nor the overhead of adapting code to run effectively in such a system. Instead, YesWorkflow enables scientists to annotate existing scripts with special comments that reveal the computational modules and dataflows otherwise implicit in these scripts. YesWorkflow tools extract and analyze these comments, represent the scripts in terms of entities based on the typical scientific workflow model, and provide graphical renderings of this workflow-like view of the scripts. Future version of YesWorkflow will also allow the prospective provenance of the data products of these scripts to be queried in ways similar to those available to users of scientific workflow systems.
Academician Mileva Prvanovic - The first doctor of geometrical sciences in Serbia
Authors: Mincic Svetislav , Velimirovic Ljubica
Published: May 2015

This paper is devoted to academician Mileva Prvanovic on the occasion of her
85th birthday. We point out her influence on development of geometrical
sciences, as the first doctor oh these sciences in Serbia.
The projective curvature of the tangent bundle with natural diagonal metric
Authors: Bejan Cornelia-Livia , Druţă-Romaniuc Simona-Luiza
Published: May 2015

Our study is mainly devoted to a natural diagonal metric G on the total space
TMof the tangent bundle of a Riemannian manifold (M, 1). We provide the
necessary and sufficient conditions under which (TM,G) is a space form, or
equivalently (TM,G) is projectively Euclidean. Moreover, we classify the
natural diagonal metrics G for which (TM,G) is horizontally projectively flat
(resp. vertically projectively flat).
On canonical-type connections on almost contact complex Riemannian manifolds
Authors: Manev Mancho
Published: May 2015

We consider a pair of smooth manifolds, which are the counterparts in the
even-dimensional and odd-dimensional cases. They are separately an almost
complex manifold with Norden metric and an almost contact manifolds with
B-metric, respectively. They can be combined as the so-called almost contact
complex Riemannian manifold. This paper is a survey with additions of results
on differential geometry of canonical-type connections (i.e. metric
connections with torsion satisfying a certain algebraic identity) on the
considered manifolds.
On the structure tensors of almost contact B-metric manifolds
Authors: Manev Hristo
Published: May 2015

The space of the structure (0,3)-tensors of the covariant derivatives of the
structure endomorphism and the metric on almost contact B-metric manifolds is
considered. A known decomposition of this space in orthogonal and invariant
subspaces with respect to the action of the structure group is used. We
determine the corresponding components of the structure tensor and consider
the case of the lowest dimension 3 of the studied manifolds. Some examples
are commented.
Classical linear connections from projectable ones on vertical Weil bundles
Authors: Kurek Jan , Mikulski Włodzimierz
Published: May 2015

We essentially reduce the problem of describing all natural operators Qproj
QVA lifting projectable classical linear connections on fibred manifolds to
classical linear connections on vertical Weil bundles.
On some classes of generalized quasi Einstein manifolds
Authors: Güler Sinem , Demirbağ Sezgin
Published: May 2015

In the present paper, we investigate generalized quasi Einstein manifolds
satisfying some special curvature conditions R?S = 0,R?S = LSQ(g,S), C?S =
0,?C?S = 0,?W?S = 0 and W2?S = 0 where R, S, C,?C,?W and W2 respectively
denote the Riemannian curvature tensor, Ricci tensor, conformal curvature
tensor, concircular curvature tensor, quasi conformal curvature tensor and
W2-curvature tensor. Later, we find some sufficient conditions for a
generalized quasi Einstein manifold to be a quasi Einstein manifold and we
show the existence of a nearly quasi Einstein manifolds, by constructing a
non trivial example.
Curvature properties of some class of minimal hypersurfaces in Euclidean spaces
Authors: Deszcz Ryszard , Głogowska Małgorzata , Petrovic-Torgasev Miroslava , Verstraelen Leopold
Published: May 2015

We determine curvature properties of pseudosymmetry type of some class of
minimal 2-quasiumbilical hypersurfaces in Euclidean spaces En+1, n ? 4. We
present examples of such hypersurfaces. The obtained results are used to
determine curvature properties of biharmonic hypersurfaces with three
distinct principal curvatures in E5. Those hypersurfaces were recently
investigated by Y. Fu in [38].
On the existence of isoperimetric extremals of rotation and the fundamental equations of rotary diffeomorphisms
Authors: Mikes Josef , Sochor Martin , Stepanova Elena
Published: May 2015

In this paper we study the existence and the uniqueness of isoperimetric
extremals of rotation on two-dimensional (pseudo-) Riemannian manifolds and
on surfaces on Euclidean space. We find the new form of their equations which
is easier than results by S. G. Leiko. He introduced the notion of rotary
diffeomorphisms. In this paper we propose a new proof of the fundamental
equations of rotary mappings.
Finslerian-type GAF extensions of the Riemannian framework in digital image processing
Authors: Balan Vladimir , Stojanov Jelena
Published: May 2015

Digital image processing was recently proved to be successfully approached by
variational tools, which extend the Casseles-Kimmel-Sapiro weighted length
problem. Such tools essentially lead to the socalled Geodesic Active Flow
(GAF) process, which relies on the derived mean curvature flow PDE. This
prolific process is valuable due to both the provided numeric mathematical
insight, which requires specific nontrivial choices for implementing the
related algorithms, and the variety of possible underlying specific
geometric structures. A natural Finsler extension of Randers type was
recently developed by the authors, which emphasizes the anisotropy given by
the straightforward gradient, while considering a particular scaling of the
Lagrangian. The present work develops to its full extent the GAF process to
the Randers Finslerian framework: the evolution equations of the model are
determined in detail, Matlab simulations illustrate the obtained theoretic
results and conclusive remarks are drawn. Finally, open problems regarding
the theoretic model and its applicative efficiency are stated.
On locally conformal Kaehler space forms
Authors: Mutlu Pegah , Sentürk Zerrin
Published: May 2015

The notion of a locally conformal Kaehler manifold (an l.c.K-manifold) in a
Hermitian manifold has been introduced by I. Vaisman in 1976. In [2], K.
Matsumoto introduced some results with the tensor Pij is hybrid. In this
work, we give a generalisation about the results of an l.c.K-space form with
the tensor Pij is not hybrid. Moreover, the Sato?s form of the holomorphic
curvature tensor in almost Hermitian manifolds and l.c.K-manifolds are
presented.
Data mining approach for in-hospital treatment outcome in patients with acute coronary syndrome
Authors: Sladojevic Miroslava , Cankovic Milenko , Cemerlic Snezana , Mihajlovic Bojan , Adjic Filip , Jarakovic Milana
Published: May 2015

Introduction. Risk stratification is nowadays crucial when estimating the
patient?s prognosis in terms of treatment outcome and it also helps in
clinical decision making. Several risk assessment models have been developed
to predict short-term outcomes in patients with acute coronary syndrome. This
study was aimed at developing an outcome prediction model for patients with
acute coronary syndrome submitted to percutaneus coronary intervention using
data mining approach. Material and Methods. A total of 2030 patients
hospitalized for acute coronary syndrome and treated with percutaneous
coronary intervention from December 2008 to December 2011 were assigned to a
derivation cohort. Demographic and anamnestic data, clinical characteristics
on admission, biochemical analysis of blood parameters on admission, and left
ventricular ejection fraction formed the basis of the study. A number of
machine learning algorithms available within Waikato Environment for
Knowledge Discovery had been evaluated and the most successful was chosen.
The predictive model was subsequently validated in a different population of
931 patients (validation cohort), hospitalized during 2012. Results. The best
prediction results were achieved using Alternating Decision Tree classifier,
which was able to predict in-hospital mortality with 89% accuracy, and
preserved good performance on validation cohort with 87% accuracy.
Alternating Decision Tree classifier identified a subset of 6 attributes most
relevant to mortality prediction: systolic and diastolic blood pressure,
heart rate, left ventricular ejection fraction, age, and troponin value.
Conclusion. Data mining approach enabled the authors to develop a model
capable of predicting the in-hospital outcome following percutaneous coronary
intervention. The model showed excellent sensitivity and specificity during
internal validation.
Articulation disorders in Serbian language in children with speech pathology
Authors: Dmitric Tanja , Veselinovic Mila , Mitrovic Slobodan
Published: May 2015

Introduction. Articulation is the result of speech organs and it means clean,
clear and distinct pronunciation of voices in words. Material and Methods. A
prospective study included 24 children between 5 and 15 years of age, of both
sexes. All children were monolingual, Serbian being their native language.
The quality of articulation was tested with Triage articulation test.
Results. Neither omission nor distortion of plosives was observed in any of
them, whereas substitution of plosives occurred in 12% of patients. Omission
of affricates was not observed in any of the subjects, but substitution and
distortion occurred in 29%, and 76% of subjects, respectively. Omission of
fricatives was found in 29% subjects, substitution in 52%, and distortion in
82% of subjects. Omission and distortion of nasals was not recorded in any of
the subjects, and substitution occurred in 6% of children. Omission of
laterals was observed in 6%, substitution in 46% and distortion in 52% of
subjects with articulation disorders. Discussion and Conclusion. Articulation
disorders were observed not only in children diagnosed with dyslalia but in
those with dysphasia and stuttering as well. Children with speech disorders
articulate vowels best, then nasals and plosives. Articulation of fricatives
and laterals was found to be most severely deviated, including all three
disorders, i.e. substitution, omission and distortion. Spasms of speech
muscles and vegetative reactions were also observed in this study, but only
in children with stuttering.
Risk factors for bilateral anterior cruciate ligament injuries
Authors: Ristic Vladimir , Ristic Sinisa , Maljanovic Mirsad , Djan Vladimir , Milankov Vukadin , Harhaji Vladimir
Published: May 2015

Introduction. The aim of this study has been to identify which risk factors
can influence bilateral anterior cruciate ligament injury. Material and
Methods. Thirty-two operated patients took part in this survey during the
period of ten years. There were 5 women and 27 men, with average age of 30.46
years (19-55). The respondents filled in the questionnaire by answering the
questions regarding the time when getting injured and operated, mechanism of
injuries, genetic and anthropometric data, characteristics of sports and
every day activities. Results. The incidence of reconstructed bilateral
injuries in relation to unilateral ones was 2.3% (50/2168). The age of
respondents and side of the injured knee did not correlate significantly with
the achieved subjective physical activity level after the second knee
surgery. The average time from the first injury to operation was 10 months
and 4.3 years since that moment up to the injury of the other knee. It took
more than 9 months on average until the reconstruction of contralateral
anterior cruciate ligament. The most of athletes were injured in football
matches. Three-quarters of athletes returned to competition activities after
the first operation, which caused the same injury of the contralateral knee.
Discussion and Conclusion. Anterior cruciate ligament rupture of the
contralateral knee most often occurs in young active athletes within the
first four years after the initial reconstruction. Its frequency is not
affected by sex, side of extremity, genetic predisposition, type of sport,
concomitant injuries and the choice of graft. Returning to the same or higher
level of sports activities after the first reconstruction is one of the
preconditions for injuring the other knee in the same way.
Dr Avram Jozef Vinaver (1862-1915): Pioneer of radiology in Serbia
Authors: Babic Rade , Stankovic-Babic Gordana
Published: May 2015

Introduction. Dr Abraham Joseph Vinaver (1862-1915), a Jew from Poland, was a
pioneer of radiology in Serbia. He graduated from the Faculty of Medicine in
Warsaw (1887), but lived and worked in Sabac (the Kingdom of Serbia) since
1890. Dr Abraham Joseph Vinarev - Career Development. He procured the first
X-ray machine and developed radiological service in Sabac five years after
the discovery of X-rays. These were the beginnings of radiology in Serbia.
He introduced the application of artesian wells. Dr Abraham Joseph Vinarev -
a Participant at the First Congress of Serbian Physicians and Naturalists,
Belgrade 1904. ?The diagnostic importance of X-rays in lung disease,
especially in initial tuberculosis? and ?Five Years of Treatment by X-Ray
Machines? were the first works in the field of radiology in Serbia by this
author. Dr Abraham Joseph Vinaver - Reserve Medical Officer in the Serbian
Army. During the Balkan Wars, he was a volunteer with the rank of major
engaged in military corps and he participated in the First World War as
well. He died of malaria in 1915 in Gevgelija. ?Dr Avram Vinaver?- Stanislav
Vinarev. His dedication to work during the typhus epidemics was put into
verses of a poem by his son Stanislav Vinarev. Conclusion. Dr Avram Vinaver
Joseph was a noble man with a great heart, who selflessly sacrificed himself
for the Serbian people and Serbia. He gave his contribution to the
development of health services in Serbia, both in peacetime and wartime
conditions. Dr Abraham Joseph Vinaver laid the foundations for today?s
radiology in Serbia.
Bone Morphogenetic Protein 4 and Smad1 Mediate Extracellular Matrix Production in the Development of Diabetic Nephropathy
Authors: Matsubara Takeshi , Araki Makoto , Abe Hideharu , Ueda Otoya , Jishage Kou-ichi , Mima Akira , Goto Chisato , Tominaga Tatsuya , Kinosaki Masahiko , Kishi Seiji , Nagai Kojiro , Iehara Noriyuki , Fukushima Naoshi , Kita Toru , Arai Hidenori , Doi Toshio
Published: May 2015

Diabetic nephropathy is the leading cause of end-stage renal disease. It is pathologically characterized by the accumulation of extracellular matrix in the mesangium, of which the main component is α1/α2 type IV collagen (Col4a1/a2). Recently, we identified Smad1 as a direct regulator of Col4a1/a2 under diabetic conditions in vitro. Here, we demonstrate that Smad1 plays a key role in diabetic nephropathy through bone morphogenetic protein 4 (BMP4) in vivo. Smad1-overexpressing mice (Smad1-Tg) were established, and diabetes was induced by streptozotocin. Nondiabetic Smad1-Tg did not exhibit histological changes in the kidney; however, the induction of diabetes resulted in an ∼1.5-fold greater mesangial expansion, consistent with an increase in glomerular phosphorylated Smad1. To address regulatory factors of Smad1, we determined that BMP4 and its receptor are increased in diabetic glomeruli and that diabetic Smad1-Tg and wild-type mice treated with a BMP4-neutralizing antibody exhibit decreased Smad1 phosphorylation and ∼40% less mesangial expansion than those treated with control IgG. Furthermore, heterozygous Smad1 knockout mice exhibit attenuated mesangial expansion in the diabetic condition. The data indicate that BMP4/Smad1 signaling is a critical cascade for the progression of mesangial expansion and that blocking this signal could be a novel therapeutic strategy for diabetic nephropathy.
Ecosystem services and energy crops – spatial differentiation of risks
Authors: Bastian Olaf , Lupp Gerd , Syrbe Ralf-Uwe , Steinhäußer Reimund
Published: May 2015

The increased cultivation of energy crops has a variety of economic, social and environmental effects, which can be assessed using the concept of ecosystem services (ES). Among the various instruments for regulating energy crop cultivation, reducing the impacts on ecosystems and landscapes, and moving sustainable land management forward, the ES concept is a useful tool since it includes economic, ecological and social aspects. The methodological approach is exemplified by a case study in the district of Gorlitz, Germany. It started with an indicator-based analysis of the present state of landscape functions or services, focusing on the “supply” part of ES assessments. The results were interpreted in light of an ecological risk assessment concerning intensified agriculture in general and the increased cultivation of energy crops in particular: on the one hand for the present situation, and on the other, for three different future scenarios. It was possible to project the results onto reference units (biophysical units), and to reveal spatial differences in carrying capacity or sensibility as a result of increased energy crop cultivation. The demand side of ESs was assessed on the basis of semi-structured interviews and standardized questionnaires.
Limnological study of Serbian oxbow shaped Lake Srebrno, with special emphasis on the benthic community composition and structure
Authors: Martinovic-Vitanovic Vesna , Ostojic Snezana , Popovic Natasa , Rakovic Maja , Kalafatic Vladimir
Published: May 2015

Detailed limnological study of the Lake Srebrno (Serbia) bottom fauna was performed in March 2007. Investigations included qualitative, quantitative, and saprobiological analysis of bottom fauna communities, physical and chemical analysis of sediments and determination of chlorophyll a concentration, as well as saprobic and trophic status analyses. Samples were collected at eighteen sites distributed along a shoreline and in deeper sections of the lake. Twenty taxa from nine macroinvertebrate groups were recorded. Family Chironomidae had the biggest index of participation, the highest species diversity and the largest density of populations in benthocenoses of Lake Srebrno. Faunistic similarity between sites was estimated according to Sorensen’s Quotient of Similarity (QS). The majority of benthocenoses - 56% showed a medium level of faunistic similarity (QS = 21-60%), and 42% of benthocenoses showed a high level of faunistic similarity (QS = 61-100%). The classification of Lake Srebrno based on saprobic and trophic levels was assessed. Saprobic level was in the range from alpha-meso- to poly-alpha-mesosaprobity. The water quality of the lake ranged from class III and between IV and III class. Generally, Lake Srebrno had eutrophic status with the gradation to hypertrophy.
The relations between land surface morphometry and spectral characteristics of ecosystems in the Ukrainian Carpathians
Authors: Mkrtchian Alexander
Published: May 2015

Spatial planning in mountainous areas requires careful consideration of relationships between abiotic conditions and various ecosystem properties. While detailed spatial databases of these and also detailed ecological databases built on field data are still lacking for many regions, satellite data are an indispensable source of spatially distributed detailed ecological information. Digital elevation models and multi-spectral images are especially useful for the acquisition of detailed, up-to-date and cheap spatial data. In this study, principal component analysis and canonical correlation analysis were used to reveal the structure of the relationships between the land surface reflectance values in different wavelength ranges and to investigate relationships between the principal components and the set of topographic characteristics and indexes for the study area in the Ukrainian Carpathians. The most important factor that influences the land and vegetation cover structure was found to be elevation, while other factors included a set of topographic characteristics and indices.
Land cover dynamics in western Bieszczady Mts between 19th and 20th century
Authors: Klich Daniel , Gielarek Sylwia , Antosiewicz Magdalena
Published: May 2015

The aim of this paper was to indicate the main directions in cover changes and land use in Western Bieszczady Mts. Two areas differing in altitudes, were taken into analysis: part of Bieszczady Wysokie Mts (for years 1852 and 2004) and Baligrod Forest District area (for years 1938 and 1996). Changes in land cover were estimated based on map overlapping, and using indices of changes. Transformations related to almost 40% of Baligrod Forest District area and insignificantly less in Bieszczady Wysokie Mts. Within the study areas, regions with considerable stability and also regions with intensive changes on vast areas appeared. The origin of differences in the land use of both study areas emerged not only from natural changes, but also from historical, social and economic changes.
Fractal analysis of leaves: are all leaves self-similar along the cane?
Authors: Gazda Anna
Published: May 2015

The fractal dimension can be used to quantify the shape of a natural curve. Curves with similar degrees of irregularity will tend to have the same fractal dimension. The fractal exponent describes the complexity of a shape and characterizes the scale-dependency of the pattern. This article presents an application of the fractal dimension in the analysis of leaves shape. In this paper I attempt to ask question if leaves of blackberry characterized by fractal dimension differ significantly in relation to the leaf ’s position along the cane. The fractal dimension of 49 leaves of blackberry from 8 primocanes, and 53 leaves from 19 lateral canes, from 9 individuals was estimated. The mean of D of a leaf is 1.12. There are no significant differences between D for leaves from two different cane types. Previous studies were focused on measurements of fractal dimension of leaves randomly chosen from one or a few individuals so there was necessity to measure fractal dimension all leaves growing along the same shoot, because usually leaf shape and size change more or less along a shoot. This research confirmed that fractal dimension is much more related to the shape complexity than to the size of leaves.
Molluscan communities in Late Holocene fluvial deposits as an indicator of human activity: A study in Podhale basin in South Poland
Authors: Alexandrowicz Witold Paweł
Published: May 2015

The localities of Late Holocene fluvial sediments in the Podhale basin were subjected to malacological analysis. Two types of mollusc communities were found in these formations. The first type is characterized by a high proportion of species typical of open environments such as the zones of wide valleys. The predomination of shade-loving taxa is typical of the second type which is mainly associated with narrow, V-shaped type valleys. Malacological analysis allowed characterization of these communities and reconstruction of environmental changes over the last few hundred years. Particular attention was paid to the reconstruction of the history of human settlement in the Podhale region and its impact on the transformation of the environment. This impact resulted in massive deforestation and the introduction of wide-scale farming and pastoral practices. Application of this malacological analysis enabled the determination of the anthropogenic pressures, and changes in their intensity, over the last few hundred years.
Development of soil parameters and changing landscape structure in conditions of cold mountain climate (Case Study Liptovsk Á Teplička)
Authors: Fazekašová Danica , Boltižiar Martin , Bobuľská Lenka , Kotorová Dana , Hecl Ján , Krnáčová Zdena
Published: May 2015

Fazekašova D., Boltižiar M., Bobuľska L., Kotorova D., Hecl J., Krnačova Z.: Development of soil parameters and changing landscape structure in conditions of cold mountain climate (case study Liptovska Teplička). Ekologia (Bratislava), Vol. 32, No. 2, p. 197-210, 2013.

Soil physical, chemical and biological properties and the content of heavy metals were investigated between 1997 and 2010 and changing landscape structure was evaluated for years 1948-2010 under production conditions in the investigated area Liptovska Teplička (48° 57´ N; 20° 05´ E), situated in the marginal region of north-eastern Slovakia. Research showed that soil physical properties get adjusted after a long-term application of ecological farming system and the measured values were stabilised. High doses of organic fertilizers had positive effect on soil fertility, and thus indirectly on maintaining soil pH, available nutrients content and accumulation of humus in soil. The values of soil enzymes activities changed minimally during the research period. At the same time, it was proven that increasing the content of soil organic matter promotes natural protection of soil enzymes. This study underscores the importance of long-term, quantitative soil monitoring in determining the changes in agricultural land and ecosystem processes over time. Statistically significant effect of experimental year on all observed soil parameters was confirmed by analysis of variance. Effect of experimental locality, with the exception of pH/CaCl2, Cox and Nanorg, on other soil parameters was also statistically significant. This area represents a specific mountain grassland-arable landscape with conservation of traditional agriculture. The results of this paper also analyse landscape structure changes by using the historical maps and aerial photographs of the past 160 years.