bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamic analysis of a Kalina power unit driven by low temperature heat sources
Authors: Lolos Periklis , Rogdakis Emanuil
Published: January 2010

In this paper the operation of a reversible Kalina power cycle driven by low temperature heat sources has been studied. A numerical model has been developed to analyze thermodynamically the proposed cycle and to represent it in temperature-entropy and temperature-enthalpy diagrams. A parametric study has been conducted in order to specify the optimum values of the main parameters, i. e. low pressure, condensation and heat source temperature with respect to thermal performance. An improved configuration using a counter-current absorber instead of the conventional condenser (co-current absorber) has been proposed which has significantly higher efficiency and work output. Finally, simple equations have been derived which link the main parameters of the unit with the theoretical thermal efficiency.
Long-term optimization case studies for combined heat and power system
Authors: Polyzakis Apostolis , Malkogianni Areti , Gomes Eli , Zapounidis Kostas
Published: January 2010

In the next years distributed poly-generation systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this approach is to develop an economic and parametric analysis of a distributed generation system based on gas turbines able to satisfy the energy demand of a typical hotel complex. Here, the economic performance of six cases combining different designs and regimes of operation is shown. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and following the load could be observed in the results. Full load regime can give a shorter return on the investment then following the load. In spite combined heat and power systems being currently not economically attractive, this scenario may change in future due to environmental regulations and unavailability of low price fuel for large centralized power stations. Combined heat and power has a significant potential although it requires favorable legislative and fair energy market conditions to successfully increase its share in the power generation market.
Numerical solution of Stefan problem with time-dependent boundary conditions by variable space grid method
Authors: Savovic Svetislav , Caldwell James
Published: January 2010

The variable space grid method based on finite differences is applied to the one-dimensional Stefan problem with time-dependent boundary conditions describing the solidification/melting process. The temperature distribution, the position of the moving boundary and its velocity are evaluated in terms of finite differences. It is found that the computational results obtained by the variable space grid method exhibit good agreement with the exact solution. Also the present results for temperature distribution are found to be more accurate compared to those obtained previously by the variable time step method.
Turbulent flow and heat transfer characteristics in U-tubes: A numerical study
Authors: Alammar Khalid
Published: January 2010

Using the standard k-e model, 3-dimensional turbulent flow and heat transfer characteristics in U-tubes are investigated. Uncertainty is approximated using experimental correlations and grid independence study. Increasing the Dean number is shown to intensify a secondary flow within the curved section. The overall Nusselt number for the tube is found to decrease substantially relative to straight tubes, while the overall skin friction coefficient remains practically unaffected. Local skin friction coefficient, Nusselt number, and wall temperature along the tube wall are presented.
Heat transfer correlation for a refrigerant mixture in a vertical helical coil evaporator
Authors: Raja Balakrishnan , Santhappan Sekhar , Dhasan Lal
Published: January 2010

The flow boiling heat transfer study of R-134a/R-290/R-600a refrigerant mixture is carried out in a vertical helical evaporator test section. The test section is immersed in an agitated ethylene glycol-water bath maintained at constant temperature. An aluminum test section with a height of 0.22 m, tube inside diameter of 6.35 mm, outside diameter of 8 mm and coil length of 8 m is used. The influences of various operating parameters such as evaporating temperature, bath temperature, and refrigerant composition on the heat transfer coefficient are investigated experimentally. Using the same experimental results the shell side flow boiling heat transfer coefficient correlation in helical evaporator is also evolved.
Preliminary studies on global solar radiation in Mbalmayo, Cameroon
Authors: Akpabio Louis , Udoimuk Akpan , Etuk Sunday
Published: January 2010

This paper presents preliminary studies on the global solar radiation in a horizontal surface along with the prevailing meteorological conditions measured during the period 1999-2001 in Mbalmayo, Cameroon. Hourly, daily, and mean monthly values of global solar radiation and meteorological data were obtained from the International Institute of Tropical Agriculture automatic weather station of Mbalmayo. The data were processed as daily, hourly, sum of 10-day data for 8.00/12.00/16.00/20.00 hours, decadal hourly, decadal daily, and mean monthly data. The highest measured daily, decadal hourly, decadal daily, and mean monthly data for global solar radiation in Mbalmayo was found to be 29.7, 2.76, 21.8, and 20.1 MJm2, respectively. The highest hourly global solar radiation value up to 182.44 MJm2 was observed between March 21-31, 1999. Apart from the global solar radiation measurements, the main observed meteorological parameters were, soil temperature, temperature, wind speed, precipitation, and relative humidity. The results show that there exist seasonal tendencies in the variation of global solar radiation. The range of variation of these radiations and the distribution puts Mbalmayo has a high potential for solar energy utilization.
Experimental and numerical modelling of thermal performance of a residential building in Belgrade
Authors: Vucicevic Biljana , Turanjanin Valentina , Bakic Vukman , Jovanovic Marina , Stevanovic Zana
Published: January 2010

The main objective of this paper is to evaluate simulation of thermal performance of a residential 4 floors high building placed in the suburb of Belgrade (ground and 3 upper floors) with it's total surface area of 1410 m2. It's supplied with liquid petroleum gas storage tank as a fuel reservoir since there is automatic gas boiler in each apartment. Measurements have been carried out in first floor apartment (68 m2 heating area) in heating season period. Measured parameters are: inside and outside air temperature and U-value of apartment envelope. Weather data is obtained by using METEONORM, the software package for climatic data calculation based on last 10 years measurements. TRNSYS 16 has been used as the simulation tool. The behavior of the building in terms of heating loads for climate on a daily and monthly basis in heating season is investigated. The calculations show possibility for saving energy by optimization inside temperature during different gas boiler working regimes.
Educational progressivism: Theory and practice
Authors: Milutinovic Jovana
Published: January 2010

The theory and main characteristics of progressivism are studied in the paper. The starting point for research of progressive education is the analysis of its philosophical, psychological and ideological foundations. Numerous aspects of progressivism are discussed in that context: goals of education and learning, role of school, nature of knowledge and the choice of educational contents, viewpoints on instruction and learning, as well as the position of teachers and students in educational process. In this, the intention is not to analyze only the theory of progressivism, but also to point out its practical aspects by describing the work of schools which have largely accepted the progressive ideas from the first half of the twentieth century with the intention of their further development. In that sense, this paper is also an attempt of studying the application of progressive ideas in practice in contemporary education. It is concluded that, notwithstanding the amount of criticism coming from other schools of thought, progressivism in education was and has remained an important reformation movement. Open schools, schools without grades, cooperative learning, multi-generation grouping in classrooms, experiential learning and numerous programs of alternative schools are the examples of infiltration of progressive ideas in contemporary educational practice.
Using focus groups to give voice to school underachievers
Authors: Dzinovic Vladimir
Published: January 2010

This paper analyses discourses on school failure of gymnasium students. Research strategy for establishment of dialogue with students is focus group. The method of analysis of the material obtained in the conversations with students is discourse analysis. First, two dominant strategies of focus group usage are discussed: as means for collecting data from subjects and as a social emancipatory practice. The prevailing discourses about school failure of students are mapped: the discourse of school as an insecure investment, the discourse of school marginalisation, the discourse of disinterest of students, the discourse of disinterest of teachers and the discourse 'school success does not have an alternative'. The concluding part discusses research implications on social position of students in power relations in education.
Involving teachers in school development
Authors: Stankovic Dejan
Published: January 2010

One of the key messages of the contemporary approach to school development is that teacher participation is a necessary precondition for the successfulness of this process. Experience from the world, however, shows that broad and active participation of teachers in school development is neither easy to achieve nor to sustain in the long run. Similarly, the first experiences with school developmental planning in Serbia from the first half of this decade also pointed out to the differences with respect to readiness of teachers to take over this new role. The research that will be presented in this paper was conducted with the aim of discovering and determining the levels and ways in which different factors influence teacher involvement in developmental activities in school, whereby those activities are of cooperative and leadership character. The research was conducted on the sample of 385 teachers from 51 primary schools in Serbia. The findings indicate that teacher involvement in school development is a product of a complex combination and interaction of numerous personal and contextual factors, bearing in mind that harmony of personal and professional identity and meanings ascribed to changes in school is of primary importance. The final part of the paper provides recommendations for system and organizational level in order for teacher involvement in school development to become a widespread and sustainable practice.
Students' autonomy and teacher's interpersonal style in self-determination theory
Authors: Lalic-Vucetic Natasa , Djeric Ivana , Djevic Rajka
Published: January 2010

Starting from psychological needs that are considered basic within self-determination theory (autonomy, competence and relatedness), the importance of encouraging students' autonomy in school context is particularly emphasised. Appreciation of students' autonomy has a stimulating effect on school achievement, conceptual understanding, creativity development, strengthening of self-esteem, and students adapt better to school system and demonstrate a larger degree of internalisation of school rules and intrinsic motivation. Teachers' behavioural style largely determines the degree of students' autonomy in school life and work. Self-determination theory implies the necessity of agreement between the developmental need for autonomy in children and the level of adult control and distinguishes between two styles of interpersonal behavior of teachers: (a) those who offer support to students' autonomy by their behavior and (b) those that are predominantly inclined to control students' behavior. This paper also points out to different strategies that can be applied by teachers in working with students in school, which also contribute to the development of students' autonomy. What is especially encouraging is the fact that it is possible to learn and to develop 'appreciation of students' autonomy' as teacher's interpersonal style.
Language of textbooks in narrative subjects: Understanding words in the seventh grade of primary school
Authors: Lazarevic Emilija , Sefer Jasmina
Published: January 2010

Hermetic textbook language poses a significant problem in education of the young in our country. The goal of this paper is to point out to the complexity of vocabulary in textbooks, which contributes to students' lack of understanding of what they are reading. Since we established that textbooks in narrative subjects - history, geography and biology - are mostly used during studying and that students mark them as especially difficult for understanding, the subject of this research is precisely the analysis of words which seventh-grade students from primary school state as unfamiliar on a randomly selected, but balanced in terms of length, textbook text of those subjects. The results of frequency analysis indicate that there are a lot of unfamiliar expert words, and frequently the same number, or even more, of common Serbian words in textbook texts, especially in history. Approximately the same or even larger number of unfamiliar words occurs in familiar texts when compared to unfamiliar, which indicates that the previous usage of texts does not contribute to their understanding. Based on correlation analysis referring to the number of unfamiliar words, frequency of textbook usage, perception of difficulty of the text in textbook, general and the achievement in the particular subject, it was determined that unfamiliar words are not only mentioned by students with low grades, although they do it more often, nor that only these students are the ones complaining how difficult textbooks are to them. Based on regression analysis, the number of unfamiliar words, especially in the history textbook, even figures as a predictor of success, which seems contradictory and can be interpreted differently. The results point out to the fact that inaccessibility of textbook language mostly does not guide the students to learn new words, but causes revolt and thus disables the development of language, scientific concepts and acquiring professional terminology, which remains inaccessible even after having been studied in school.
Knowledge of geographical map at the end of primary school education in Serbia
Authors: Komlenovic Djurdjica
Published: January 2010

The paper presents the results of one part of empirical research conducted for the purpose of conceiving the proposal of educational standards for the subject Geography at the end of primary school education. The goal was to determine the extent to which the students were trained to orient themselves and use cartographic method in the process of using geographical map. Research comprised the representative sample of 919 students of the final grade in 159 Serbian primary schools. Achievement Test served for studying the levels of students' knowledge and skills in the field of Geographic Skills. Besides this, the questionnaire studied students' opinion on learning outcomes in this field, and by analyzing contingency tables, the correlation between students' success in geography at the end of the first term of the eighth grade and their opinion about learning outcomes in the afore-mentioned field was determined. The findings of this research indicate that students are not sufficiently trained to orient themselves in space and on geographical map, as well as to use geographical map in instruction. Besides, it was established that there is a correlation between students' success and their opinion on learning outcomes in the field of Geographic Skills.
Recurrence of Type 1 Diabetes After Simultaneous Pancreas-Kidney Transplantation, Despite Immunosuppression, Is Associated With Autoantibodies and Pathogenic Autoreactive CD4 T-Cells
Authors: Vendrame Francesco , Pileggi Antonello , Laughlin Elsa , Allende Gloria , Martin-Pagola Ainhoa , Molano R. Damaris , Diamantopoulos Stavros , Standifer Nathan , Geubtner Kelly , Falk Ben A. , Ichii Hirohito , Takahashi Hidenori , Snowhite Isaac , Chen Zhibin , Mendez Armando , Chen Linda , Sageshima Junichiro , Ruiz Phillip , Ciancio Gaetano , Ricordi Camillo , Reijonen Helena , Nepom Gerald T. , Burke George W. , Pugliese Alberto
Published: January 2010

OBJECTIVE

To investigate if recurrent autoimmunity explained hyperglycemia and C-peptide loss in three immunosuppressed simultaneous pancreas-kidney (SPK) transplant recipients.

RESEARCH DESIGN AND METHODS

We monitored autoantibodies and autoreactive T-cells (using tetramers) and performed biopsy. The function of autoreactive T-cells was studied with in vitro and in vivo assays.

RESULTS

Autoantibodies were present pretransplant and persisted on follow-up in one patient. They appeared years after transplantation but before the development of hyperglycemia in the remaining patients. Pancreas transplant biopsies were taken within ∼1 year from hyperglycemia recurrence and revealed β-cell loss and insulitis. We studied autoreactive T-cells from the time of biopsy and repeatedly demonstrated their presence on further follow-up, together with autoantibodies. Treatment with T-cell–directed therapies (thymoglobulin and daclizumab, all patients), alone or with the addition of B-cell–directed therapy (rituximab, two patients), nonspecifically depleted T-cells and was associated with C-peptide secretion for >1 year. Autoreactive T-cells with the same autoantigen specificity and conserved T-cell receptor later reappeared with further C-peptide loss over the next 2 years. Purified autoreactive CD4 T-cells from two patients were cotransplanted with HLA-mismatched human islets into immunodeficient mice. Grafts showed β-cell loss in mice receiving autoreactive T-cells but not control T-cells.

CONCLUSIONS

We demonstrate the cardinal features of recurrent autoimmunity in three such patients, including the reappearance of CD4 T-cells capable of mediating β-cell destruction. Markers of autoimmunity can help diagnose this underappreciated cause of graft loss. Immune monitoring during therapy showed that autoimmunity was not resolved by the immunosuppressive agents used.
Recurrent Moderate Hypoglycemia Ameliorates Brain Damage and Cognitive Dysfunction Induced by Severe Hypoglycemia
Authors: Puente Erwin C. , Silverstein Julie , Bree Adam J. , Musikantow Daniel R. , Wozniak David F. , Maloney Susan , Daphna-Iken Dorit , Fisher Simon J.
Published: January 2010

OBJECTIVE

Although intensive glycemic control achieved with insulin therapy increases the incidence of both moderate and severe hypoglycemia, clinical reports of cognitive impairment due to severe hypoglycemia have been highly variable. It was hypothesized that recurrent moderate hypoglycemia preconditions the brain and protects against damage caused by severe hypoglycemia.

RESEARCH DESIGN AND METHODS

Nine-week-old male Sprague-Dawley rats were subjected to either 3 consecutive days of recurrent moderate (25–40 mg/dl) hypoglycemia (RH) or saline injections. On the fourth day, rats were subjected to a hyperinsulinemic (0.2 units · kg−1 · min−1) severe hypoglycemic (∼11 mg/dl) clamp for 60 or 90 min. Neuronal damage was subsequently assessed by hematoxylin-eosin and Fluoro-Jade B staining. The functional significance of severe hypoglycemia–induced brain damage was evaluated by motor and cognitive testing.

RESULTS

Severe hypoglycemia induced brain damage and striking deficits in spatial learning and memory. Rats subjected to recurrent moderate hypoglycemia had 62–74% less brain cell death and were protected from most of these cognitive disturbances.

CONCLUSIONS

Antecedent recurrent moderate hypoglycemia preconditioned the brain and markedly limited both the extent of severe hypoglycemia–induced neuronal damage and associated cognitive impairment. In conclusion, changes brought about by recurrent moderate hypoglycemia can be viewed, paradoxically, as providing a beneficial adaptive response in that there is mitigation against severe hypoglycemia–induced brain damage and cognitive dysfunction.
Effect of Renin-Angiotensin System Blockade on Insulin Resistance and Inflammatory Parameters in Patients With Impaired Glucose Tolerance
Authors: Pscherer Stefan , Heemann Uwe , Frank Helga
Published: January 2010

OBJECTIVE

The study investigated the effect of angiotensin receptor blockers (ARB) on glucose homeostasis and inflammatory parameters in patients with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

We prospectively studied the insulin sensitivity index (ISI) and homeostasis model assessment–insulin resistance (HOMA-IR) in 13 obese males with IGT and in 13 matched control subjects with normal glucose tolerance (NGT) during hyperglycemic testing over 90 min. Adiponectin, retinol-binding protein 4 (RBP4), and high-sensitive C-reactive protein (hsCRP) were analyzed. Measurements were performed at baseline and after a 4-week treatment with 160 mg/day valsartan. The results of the IGT and NGT groups were compared.

RESULTS

At baseline, HOMA-IR (IGT 4.1 ± 3 vs. NGT 2.3 ± 1.0, P < 0.01), hsCRP (IGT 3.9 ± 1.9 vs. NGT 1.8 ± 1 mg/l, P < 0.05), and RBP4 (IGT 27.1 ± 2.1 vs. NGT 24.0 ± 2.0 ng/ml, P < 0.05) were significantly higher, whereas ISI (IGT 1.5 ± 0.9 vs. NGT 1.8 ± 1.2, P < 0.05) and plasma adiponectin (IGT 3.2 ± 0.9, NGT 5.2 ± 2.4 μg/ml, P < 0.05) were significantly lower in the IGT group compared with the NGT group. Under ARB, there was an increase in both groups of adiponectin (IGT 4.1 ± 1.9 μg/ml, NGT 6.3 ± 2.9 μg/ml, P < 0.05) and an increase in ISI (IGT 1.5 ± 0.9 to 2.3 ± 1 μg/ml, NGT 1.8 ± 1 to 2.5 ± 2 μg/ml, P < 0.05). HOMA-IR (4.1 ± 3 to 2.6 ± 2; P < 0.01), hsCRP (3.9 ± 1.9 to 1.8 ± 1 mg/l, P < 0.05), and RBP4 (27.1 ± 2.1 to 22.1 ± 1.8 ng/ml, P < 0.01) decreased significantly in the IGT group.

CONCLUSIONS

Insulin sensitivity and associated inflammatory factors improve under ARB in IGT patients.
Detection of breast cancer by soft-copy reading of digital mammograms: Comparison between a routine image-processing parameter and high-contrast parameters
Authors: Kamitani Takeshi , Yabuuchi Hidetake , Soeda Hiroyasu , Matsuo Yoshio , Okafuji Takashi , Sakai Shuji , Setoguchi Taro , Hatakenaka Masamitsu , Ishii Nobuhide , Honda Hiroshi
Published: January 2010

Background: Recent studies have reported the clinical usefulness of the soft-copy reading of mammograms. However, image-processing parameters for soft-copy reading of digital mammograms have not been established.

Purpose: To compare observer performance in detecting breast cancer by soft-copy reading of digital mammograms using a routine image-processing parameter versus each of several high-contrast parameters.

Material and Methods: The mammograms of 154 breasts, including 48 abnormal breasts with breast cancer and 106 normal breasts, were examined. Cancers were classified into 34 mass-dominant cancers, 11 microcalcification-dominant cancers, two cancers showing only architectural distortion, and one cancer without abnormal findings. All mammograms were performed using a computed radiography (CR) system. Each image was processed using GA (1.2), which was the contrast parameter recommended by the manufacturer for hard-copy film, GA (1.4), GA (1.6), and GA (1.8). These images were displayed on 5-megapixel (M) liquid-crystal display monitors. Five experienced radiologists classified them into BI-RADS category 1–2 or 3–5, and were also asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of masses and microcalcifications in each breast.

Results: In mass-dominant cancers of dense breast tissue, the mean sensitivities of GA (1.2), GA (1.4), GA (1.6), and GA (1.8) were 32.7, 38.2, 36.4, and 40.0, and the AZ values were 0.67, 0.73, 0.71, and 0.73, respectively; in microcalcification-dominant cancers, the mean sensitivities were 80.0, 74.5, 80.0, and 78.2, respectively; however, there were no significant differences among them.

Conclusion: High-contrast parameters tended to show relatively high sensitivity and AZ values in the detection of masses in dense breast tissue, but relatively low sensitivity for microcalcifications.
Low-dose contrast-enhanced magnetic resonance imaging of brain metastases at 3.0t using high-relaxivity contrast agents
Authors: Huang Biao , Liang Chang-Hong , Liu Hong-Jun , Wang Guang-Yi , Zhang Shui-Xing
Published: January 2010

Background: Lesion-to-brain contrast after gadolinium administration is significantly higher at 3.0 Tesla (T) compared to 1.5T. The high in vivo relaxivity of gadobenate dimeglumine (Gd-BOPTA) may permit the use of lower-dose contrast agents.

Purpose: To investigate whether low-dose contrast-enhanced MRI at 3.0T using a high-relaxivity contrast agent (Gd-BOPTA) can achieve a comparable or improved contrast-to-noise ratio (CNR) for the detection of brain metastases compared with examination of the same patient at 1.5T using a standard dose of gadopentetate dimeglumine (Gd-DTPA).

Material and Methods: A total of 18 patients with known brain metastases were first imaged at 1.5T with 0.1 mmol/kg Gd-DTPA. Patients returned at least 24 hours later for imaging at 3.0T with Gd-BOPTA at cumulative doses of 0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg, and 0.1 mmol/kg (0.1 mmol/kg body weight overall). The CNR of enhancing brain lesions compared to the normal contralateral white matter was calculated. For the 3.0T study using different cumulative doses of Gd-BOPTA, the CNR of lesions was compared with CNR of the same lesions imaged at 1.5T using 0.1 mmol/kg Gd-DTPA, by using the Wilcoxon matched-pairs signed-rank test.

Results: At 1.5T with 0.1 mmol/kg Gd-DTPA, the mean CNR between enhanced lesions and cerebral white matter was 12.01 ± 2.53. With 3.0T imaging using different cumulative doses of Gd-BOPTA, the mean CNRs were 7.19 ± 4.06, 15.31 ± 6.37, 25.44 ± 11.02, and 31.88 ± 13.21. At 3.0T with 0.05 mmol/kg Gd-BOPTA, CNR was 1.34-fold higher compared to CNR at 1.5T with 0.1 mmol/kg Gd-DTPA ( P <0.01).

Conclusion: Comparable contrast enhancement of brain metastases can be achieved with a 0.05-mmol/kg dose of Gd-BOPTA at 3.0T compared to imaging at 1.5T using 0.1 mmol/kg Gd-DTPA.
A pilot study to assess the feasibility of measurement of adrenal gland volume by magnetic resonance imaging
Authors: Grant Lee A. , Napolitano Antonella , Miller Sam , Stephens Kimberley , McHugh Simon M. , Dixon Adrian K.
Published: January 2010

Background: Repeated computed tomography (CT) assessment of the adrenal glands is associated with a significant radiation burden. The increasing capabilities of magnetic resonance (MR) volumetric analysis of the adrenals make this a potentially alternative technique in man.

Purpose: To determine whether MR imaging could be used to measure adrenal volume, and to determine the intra- and interobserver variation and repeatability of MR volume imaging of adrenals in healthy human subjects.

Material and Methods: This was a single-cohort, sequential design, three-part study involving four MRI examinations per subject following ethical approval and informed consent. Information was collected on four healthy subjects (three male and one female). Two different investigators estimated the area of the adrenal gland for each of the 3-mm contiguous slices (and consequently adrenal volume). In order to estimate inter- and intrareader variability, a repeated-measures mixed model was fitted with adrenal volume as the dependent variable. In order to estimate any bias between readers, Bland-Altman methodology was applied.

Results: Intraobserver variation for adrenal gland volume is approximately 5% of a 3-cm3 adrenal gland. Interobserver variation is approximately 9% of a 3-cm3 adrenal gland. Potential variation in measurement for adrenal volume from all sources equates to approximately 14% of a 3-cm3 adrenal gland. Verification of image reading by a second investigator (consensus reading) reduces variability.

Conclusion: Analysis of adrenal gland volume using MRI is a potentially reliable technique that could be used to assess a pathological change in adrenal size.
High-contrast computed tomographic angiography better detects residual intracranial arteriovenous malformations in long-term follow-up after radiotherapy than 1.5-tesla time-of-flight magnetic resonance angiography
Authors: Giesel Frederik L. , Essig Marco , Zabel-Du-Bois Angelika , Bock Michael , Tengg-Kobligk Hendrik von , Afshar-Omarei Ali , Debus Jürgen , Kauczor Hans-Ulrich , Krix Martin
Published: January 2010

Background: Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are noninvasive alternatives for therapy monitoring of cerebral arteriovenous malformation (AVM).

Purpose: To evaluate if CTA is able to detect residual AVM in the long-term follow-up after radiotherapy when time-of-flight (TOF) MRA could no longer detect a remaining nidus.

Material and Methods: 18 patients with intracranial AVM were included between November 2005 and August 2007 who were scheduled for CTA (16-slice CT, 1-mm slice thickness, 90 ml iomeprol 400 mg I/ml, 4 ml/s) in the follow-up of radiotherapy. In these patients, MRA (3D-TOF, and bolus tagging at 1.5T) could no longer detect a remaining nidus.

Results: The previously performed MRA (median time between CTA and MRA, 2.5 months) described total obliterations in 14 and subtotal obliterations in two AVM cases. Two MRA diagnoses were inconclusive due to artifacts. CTA (median time after therapy, 28 months; range, 5–66 months) could provide a diagnosis in all cases, but confirmed the MRA diagnosis only in 50% of the cases. A residual nidus was shown in an additional six cases, and subtotal obliteration in another three cases. The interval between radiotherapy and the follow-up examination was significantly different ( P<0.05) between false- and true-negative MRA examinations (median, 18 vs. 30 months).

Conclusion: High-contrast CTA is a sensitive tool in the detection of AVM and is able to identify residual AVM after radiotherapy even if previously performed TOF MRA at 1.5T shows total obliteration.
Revascularization of traumatic renal artery dissection by endoluminal stenting: Three cases
Authors: Chabrot Pascal , Cassagnes Lucie , Alfidja Agaïcha , Mballa Jean Claude , Nasser Samer , Guy Laurent , Diop Abdoulaye Ndoye , Ravel Anne , Boyer Louis
Published: January 2010

Traumatic injury of renal arteries is rare and can induce renal dysfunction and hypertension. Management options include observation, nephrectomy, surgical repair, and, more recently, percutaneous angioplasty. We report three cases of renal artery thrombosis occurring in young multitrauma patients (mean age 28.7 years) treated with stenting. Immediate satisfactory results were obtained in all cases. Postprocedure anticoagulant and antiplatelet treatment were given according to associated contraindicating lesions. During follow-up, in-stent restenosis occurred in one patient and was treated successfully with a second stenting procedure. No renal dysfunction or hypertension was observed after 28.6 months follow-up. Percutaneous angioplasty is a valuable alternative to surgical treatment in selected patients.
Comprehension of complex discourse in different stages of Huntington's disease
Authors: Saldert Charlotta , Fors Angelika , Ströberg Sofia , Hartelius Lena
Published: January 2010

Background: Huntington's disease not only affects motor speech control, but also may have an impact on the ability to produce and understand language in communication.

Aims: The ability to comprehend basic and complex discourse was investigated in three different stages of Huntington's disease.

Methods & Procedures: In this experimental group study, 18 patients with Huntington's disease completed a test that assessed basic language abilities as well as tests from a battery of tasks that explored the ability to comprehend more complex information. The test battery assessed the ability to comprehend logico‐grammatical sentences, ambiguous information and inferred meaning on sentence and discourse levels.

Outcomes & Results: In comparison with results from pair‐matched participants in a control group, matched for gender, age and education, the group of individuals with Huntington's disease had significantly more problems with all tasks requiring more complex cognitive processing. There was a correlation, as well as tendencies towards correlations, between results in the group of individuals with Huntington's disease and stage of the disease. However, results within the stage groups were heterogeneous, and some individuals in an early stage of the disease sometimes performed as well as others in a late stage.

Conclusions & Implications: It is likely that, in complex discourse tasks, individual differences in cognitive capacity may contribute and override other differences related to stage of disease. These results indicate that it is important to assess comprehension even in early stages of Huntington's disease, with tests that are sensitive to subtle language disorders, to reduce communication problems for the individuals concerned and their conversational partners.
Parents’ Involvement in the Youth Justice System: Rhetoric and Reality
Authors: Peterson-Badali Michele , Broeking Julia
Published: January 2010

The Youth Criminal Justice Act views parents as playing a critical role in both preventing and addressing youths’ criminal behaviour. However, the lack of specifically defined goals for parental involvement, in combination with potentially conflicting messages regarding parents’ roles, may result in confusion for parents, youth, and those who work in the system, confusion that may, in turn, reduce the efficacy of parents’ involvement. Through in-depth, semi-structured interviews with justice system officials (N = 41) who work with parents and young people, supplemented by direct courtroom observation of parents, we explored the reality behind the rhetoric of parental involvement. Results indicated that, despite the fact that parental involvement can have an important impact on legal outcomes for young people, and while there may be some improvement in parental involvement post-arrest under the YCJA, parents are often not involved in ways that are seen as effective and meaningful. Two kinds of conflict are seen as contributing significantly to the gap between policy and practice: interpersonal conflict between youth and their parents and conflict between the two roles that parents are expected to play – simultaneously socializing youth and promoting their legal interests in an adversarial system. Recommendations for addressing the barriers to effective parental involvement are discussed.
Blaming the Parts Instead of the Person: Understanding and Applying Neurobiological Factors Associated with Psychopathy
Authors: Freedman Lauren F. , Verdun-Jones Simon N.
Published: January 2010

This article examines the implications of the body of research that asserts that psychopaths have neurobiological irregularities that are manifested by learning and fear-processing deficits as well as neurotransmitter abnormalities. While this research suggests that psychopaths may have many neurobiological irregularities, the present article focuses on abnormalities related to the amygdala and orbitofrontal cortex of the brain, in addition to those related to neurotransmitters. It is argued that these irregularities influence the conduct of psychopaths and help to explain their propensity to engage in antisocial behaviour. Further, it is argued that these factors should mitigate the degree of criminal responsibility that is attributed to the actions of psychopathic offenders.
Guns, Gangs, and the Underclass: A Constructionist Analysis of Gun Violence in a Toronto High School
Authors: O’Grady William , Parnaby Patrick F. , Schikschneit Justin
Published: January 2010

Using data gathered from local press coverage, this article examines how the shooting death of 15-year-old Jordan Manners at a Toronto high school was framed. In particular, we seek to explain why the media's initial attempt to contextualize the event vis-à-vis the tragedy of past school shootings eventually gave way to an interpretive frame rooted in ideological presuppositions about Toronto's underclass. We argue that when the media are confronted with a “must cover” event but lack essential information, the tendency is to adopt pre-existing, consonant frameworks. We conclude by exploring the socio-political significance of such essentializing frames vis-à-vis crime in poor communities inhabited mainly by people of colour.
Classification of Sleep Stages Using Multi-wavelet Time Frequency Entropy and LDA
Authors: Lweesy K. , Khasawneh N. , Fraiwan M. , Wenz H. , Dickhaus H. , Fraiwan L.
Published: January 2010

Background: The process of automatic sleep stage scoring consists of two major parts: feature extraction and classification. Features are normally extracted from the polysomno-graphic recordings, mainly electroencephalograph (EEG) signals. The EEG is considered a non-stationary signal which increases the complexity of the detection of different waves in it.

Objectives: This work presents a new technique for automatic sleep stage scoring based on employing continuous wavelet transform (CWT) and linear discriminant analysis (LDA) using different mother wavelets to detect different waves embedded in the EEG signal.

Methods: The use of different mother wave-lets increases the ability to detect waves in the EEG signal. The extracted features were formed based on CWT time frequency entropy using three mother wavelets, and the classification was performed using the linear discriminant analysis. Thirty-two data sets from the MIT-BIH database were used to evaluate the performance of the proposed method.

Results: Features of a single EEG signal were extracted successfully based on the time frequency entropy using the continuous wavelet transform with three mother wavelets. The proposed method has shown to outperform the classification based on a CWT using a single mother wavelet. The accuracy was found to be 0.84, while the kappa coefficient was 0.78.

Conclusions: This work has shown that wavelet time frequency entropy provides a powerful tool for feature extraction for the non-stationary EEG signal; the accuracy of the classification procedure improved when using multiple wavelets compared to the use of single wavelet time frequency entropy.
Lack of Efficacy of Aurintricarboxylic Acid and Ethacrynic Acid against Vaccinia Virus Respiratory Infections in Mice
Authors: Smee Donald F , Hurst Brett L , Wong Min-Hui
Published: January 2010

Background:

Aurintricarboxylic acid (ATA) and ethacrynic acid (ECA) have been reported to exhibit antiviral activity against vaccinia virus infections in cell culture by inhibiting early and late gene transcription, respectively. The purpose of this work was to determine if these inhibitors would effectively treat vaccinia virus infections in mice, which has not previously been studied.

Methods:

ECA was investigated by cell culture plaque reduction assay for the inhibition of cowpox and vaccinia virus infections to clarify issues regarding its potency and selectivity. Mice infected intranasally with vaccinia virus were treated by intraperitoneal route twice daily for 5 days with ATA (10 and 30 mg/kg/day) and ECA (15 and 30 mg/kg/day) or once daily for 2 days with cidofovir (100 mg/kg/day).

Results:

ECA caused 50% inhibition of virus plaque formation at 20–79 μM in four cultured cell lines, with 50% cytotoxicity at 84–173 μM, giving low (1.3–4.2) selectivity index values. Preliminary toxicity tests in uninfected mice indicated that ATA and ECA were both overtly toxic at 100 mg/kg/day. No protection from mortality was afforded by treatment of vaccinia virus infections with ATA or ECA, but 100% survival was achieved in the cidofovir group. ATA- and ECA-treated mice died significantly sooner than placebo-treated animals, indicating that these compounds exacerbated the infection.

Conclusions:

Both ATA and ECA lack antiviral potency and selectivity in cell culture. The compounds were ineffective in treating mice at intraperitoneal doses of ≤30 mg/kg/day. These compounds do not appear to have potential for the treatment of poxvirus infections in vivo.
Lixiviación amoniacal de polvos de fundición de cobre y precipitación como sulfuro de cobre
Authors: Morales A. , Hevia J. F. , Cifuentes G.
Published: January 2010

Se estudió el efecto del amoniaco en la lixiviación de polvos de fundición de cobre y en la precipitación de sulfuro de cobre, usando azufre y dióxido de azufre desde estas disoluciones. La precipitación se realizó en un medio amoniacal para tener rendimientos satisfactorios a temperatura ambiente. Se precipitó un sólido que recupera alrededor del 60 % del cobre contenido en los polvos de fundición. El otro residuo generado contenía del orden del 80 % del arsénico de los polvos originales. Sobre la base de estos resultados preliminares, se planteó un procedimiento para la recuperación de cobre desde los polvos de fundición y para el confinamiento del arsénico.
Aplicación del permanganato potásico para la eliminación de cianuros de cobre en aguas residuales de la planta de lixiviación en una mina de oro (I)
Authors: Sancho J. P. , Fernández B. , Ayala J. , García M. P. , Lavandeira A.
Published: January 2010

La utilización de cianuro en las industrias químicas e hidrometalúrgicas ha supuesto la aparición de un importante problema medioambiental debido a su elevada toxicidad. Las aguas residuales generadas en estas empresas resultan peligrosas para el medio ambiente por lo que deben de ser gestionadas adecuadamente. Para ello, se tratan con procesos de detoxificación y se acumulan en balsas de contención impermeabilizadas donde pueden ser causa de desastres medioambientales. En este trabajo se presentan los resultados obtenidos en ensayos realizados en laboratorio y que demuestran la eficacia del permanganato potásico como agente oxidante de aguas residuales cianuradas, procedentes de una planta hidrometalúrgica de oro. En el proceso desarrollado se consigue la destrucción de los complejos cianurados de cobre presentes en solución y la posterior eliminación del metal por precipitación como hidróxido.
Fisuramiento en caliente en latón extruido para uso en mecanizado
Authors: Mannheim R. , Garin J.
Published: January 2010

Se estudia la falla de fisuramiento en caliente en una barra de 101 mm de diámetro, extruida en una prensa directa Schlömann de 20 MN. Después de fracturar la barra se observan áreas de finos desgarros, en la zona de mayor temperatura de la barra. Estas finas grietas se desplazan paralelas a la dirección de extrusión y, obviamente, disminuyen fuertemente las propiedades de estanqueidad de las barras. La falla en estudio, aparece en la última fase de la solidificación, en el rango de temperatura cercana a la línea solidus, la cual produce una insuficiente capacidad del material para absorber las tensiones. La condensación del plomo, producto de una heterogénea distribución de temperatura, es la que origina las grietas observadas en la barra. No obstante, la elevada temperatura del billet y la baja velocidad de extrusión, son los principales parámetros que ocasionaron la falla en estudio. Para evitar esta falla, se recomienda lo siguiente: bajar la temperatura del billet entre 660-680 °C y aumentar la velocidad de extrusión a 40 mm/s, como modo de disminuir el tiempo de extrusión en el contacto matriz-barra.
Reconocimiento automatizado de menas metálicas mediante análisis digital de imagen: un apoyo al proceso mineralúrgico. II: criterios metalogenéticos discriminantes
Authors: Castroviejo R. , Berrezueta E.
Published: January 2010

Demostrada la posibilidad de segmentación efectiva de menas metálicas para la automatización del estudio mineralógico mediante análisis digital de imagen sobre microscopio óptico de reflexión, se procede, ahora, a completar la metodología, integrando criterios complementarios. Se estudian las asociaciones minerales presentes en los yacimientos minerales y se comparan los valores de reflectancia correspondientes. Las posibilidades de confusión son mínimas, si se limita la selección a los componentes presentes en asociaciones reales. Se elaboran tablas con tipologías simplificadas de yacimientos y de las correspondientes asociaciones minerales, ilustrando su aplicación con ejemplos reales. En conclusión, se propone un método integrado que combina criterios físicos cuantitativos, basados en medidas fotoespectrométricas, con criterios geológicos (tipologías y asociaciones minerales). Dicho método no sustituye al experto mineralogista pero potencia, enormemente, su rendimiento y lo capacita, mediante el proceso matemático de datos digitales adquiridos una sola vez, para producir, a la carta, informaciones variadas y rápidas.
A REVISED SYNOPSIS OF NEARCTIC THAUMATOMYIA (=CHLOROPISCA) (DIPTERA, CHLOROPIDAE)
Authors: Sabrosky Curtis W.
Published: January 2010

Flies of the genus Thaumatomyia Zenker (=Chloropisca Loew) are small but common, and identification is frequenlly requested for faunal, ecological or other studies. Their highly polished, glabrous, usually yellow and black striped appearance stands out sharply among the many kinds of small dark flies captured by sweeping.
NEW NEARCTIC CRANE FLIES (TIPULIDAE, DIPTERA). PART XVIII.
Authors: Alexander Charles P.
Published: January 2010

In the present article I am describing a few unusually interesting species of Tipulidae from Washington, Oregon and northern California. The Oregon material was included in extensive series sent to me by Professor Herman A. Scullen, contained in the Oregon Agrircultural Experiment Station Collection, Corvallis. The Washington and California specimens, together with one species from extreme northwestern Oregon, were included in a small but very interesting series of specimens taken by Dr. and Mrs. Henry K. Townes and kindly presented to me by the collectors. I express my indebtedness to these entomologists for this continued interest in making known the crane-fly fauna of the Vancouveran faunal area.
A REVISION OF THE OBLIQUA METATA GROUP OF THE GENUS ZALE (LEPIDOPTERA, PHALAENIDAE)
Authors: McDunnough J.
Published: January 2010

For the past few years I have been working spasmodically on the species of this difficult group with a view to clearing up he existing confusion in nomenclature. To Smith must be given the credit for recognizing the fact that a greater number of species existed in the group than had been suspected by the older authors.
DESCRIPTION AND BIOLOGICAL NOTES ON A NEW SATURNIID OF THE GENUS PSEUDOHAZIS FROM THE BIG BEND REGION OF TEXAS
Authors: Tinkham E. R.
Published: January 2010

This is one of a series of papers on the desert life of the Big Bend Region of Trans-Pecos, Texas. The area concerned is mainly in Presidio and Jeff Davis Counties; the former one of the largest counties in the United States. Situated about twenty miles north of Presidio in Presidio County is the mining town of Shafter which lies in the heart of the Chinati Mountains.
THE DISTRIBUTION AND LIFE HISTORIES OF THE CADDIS FLIES OF WASKESIU LAKE, SASKATCHEWAN
Authors: Milne D. J.
Published: January 2010

A study of the caddis flies of Waskesiu Lake was carried out during the summer of 1940 as part of the general program of limnological investigations which have been conducted in Prince Albert National Park, Saskatchewan, since 1928. The importance of caddis flies in the ecology of the lake had been recognized since they provide much food for fish in the near shore reginn.