bluuebunny/crossref_metadata_2025 huggingface dataset:
SOCIOECONOMIC STATUS MEASUREMENT WITH DISCRETE PROXY VARIABLES: IS PRINCIPAL COMPONENT ANALYSIS A RELIABLE ANSWER?
Authors: Kolenikov Stanislav , Angeles Gustavo
Published: February 2009

The last several years have seen a growth in the number of publications in economics that use principal component analysis (PCA) in the area of welfare studies. This paper explores the ways discrete data can be incorporated into PCA. The effects of discreteness of the observed variables on the PCA are reviewed. The statistical properties of the popular Filmer and Pritchett (2001) procedure are analyzed. The concepts of polychoric and polyserial correlations are introduced with appropriate references to the existing literature demonstrating their statistical properties. A large simulation study is carried out to compare various implementations of discrete data PCA. The simulation results show that the currently used method of running PCA on a set of dummy variables as proposed by Filmer and Pritchett (2001) can be improved upon by using procedures appropriate for discrete data, such as retaining the ordinal variables without breaking them into a set of dummy variables or using polychoric correlations. An empirical example using Bangladesh 2000 Demographic and Health Survey data helps in explaining the differences between procedures.
Kisspeptin‐54 at high doses acutely induces testicular degeneration in adult male rats via central mechanisms
Authors: Thompson EL , Amber V , Stamp GWH , Patterson M , Curtis AE , Cooke JH , Appleby GF , Dhillo WS , Ghatei MA , Bloom SR , Murphy KG
Published: February 2009

Background and purpose:  The kisspeptins are critical regulators of reproduction and a therapeutic target for reproductive disease. Intracerebroventricular (i.c.v.) or peripheral injection of kisspeptin potently stimulates the hypothalamic‐pituitary gonadal (HPG) axis via gonadotrophin‐releasing hormone (GnRH). However, little is known regarding the effects of kisspeptin administration on testicular function. We investigated the mechanism(s) of kisspeptin‐induced testicular degeneration in the rat.

Experimental approach:  Kisspeptin‐54 (50 nmol·day−1) was continuously administered subcutaneously (6 h to 3 days) to male Wistar rats and reproductive hormones and testicular histology analysed. We also investigated the effects of a single subcutaneous injection of 0.5, 5 or 50 nmol kisspeptin‐54. In order to determine whether the testicular degeneration observed is peripherally or centrally mediated, we investigated effects of i.c.v. injections of 5 nmol kisspeptin‐54 and pre‐administered a GnRH‐receptor antagonist (cetrorelix) to rats peripherally treated with kisspeptin‐54.

Key results:  Continuous subcutaneous administration of kisspeptin‐54 caused testicular degeneration after only 12 h, when gonadotrophins were still markedly raised, suggesting that the degeneration is independent of the desensitization of the HPG axis to kisspeptin‐54. Furthermore, a single subcutaneous injection of kisspeptin‐54 caused dose‐dependent testicular degeneration. Continuous kisspeptin‐54 administration is thus not required to cause testicular degeneration. Pretreatment with cetrorelix blocked kisspeptin‐induced testicular degeneration, and a single i.c.v. injection of kisspeptin‐54 caused testicular degeneration, suggesting it is GnRH‐mediated.

Conclusions and implications:  Kisspeptin‐induced testicular degeneration appears to be centrally mediated, and result from acute hyper‐stimulation of the HPG axis. Doses must be carefully considered if kisspeptin is to be used therapeutically.

Mandarin translation of abstract
Glomuvenous Malformation in a Boy with Transposition of the Great Vessels: A Case Report and Review of Literature
Authors: Chen Amy Y. Y. , Eide Melody , Shwayder Tor
Published: February 2009

Abstract:  We report a case of glomuvenous malformation (GVM) in an 11‐year‐old boy with a history of transposition of the great vessels. The glomulin gene was discovered in 1999, and multiple mutations have been identified with some of the mutations resulting in GVM. The molecular genetics, clinical presentation, histopathology, differential diagnosis, and management of GVM are reviewed. To our knowledge, no case of glomuvenous malformation in the setting of transposition of the great vessels has ever been reported in the literature.
Heck's Disease: Diagnosis and Susceptibility
Authors: Bennett Lindsey K. , Hinshaw Molly
Published: February 2009

Abstract:  Focal epithelial hyperplasia, or Heck's disease, is an uncommon proliferation of oral mucosa that presents primarily in Native Central and South American populations. It presents as asymptomatic papules or nodules on the oral mucosa, gingiva, tongue, and lips. In the majority of cases, human papilloma virus 13 or 32 is detected. Factors that determine disease susceptibility are unclear, but genetics, and having the human lymphocytic antigen‐DR4 (DRB1*0404) allele in particular, are thought to play a major role in disease vulnerability. We report another case of focal epithelial hyperplasia, hypothesize on disease susceptibility, and review the current understanding of this uncommon disorder.
Climatotherapy at the Dead Sea for Pediatric‐Onset Psoriasis Vulgaris
Authors: BEN‐AMITAI Dan , DAVID MICHAEL
Published: February 2009

Abstract:  Climatotherapy at the Dead Sea is highly effective and safe for the treatment of psoriasis vulgaris in adults. We examine the efficacy and safety of climatotherapy at the Dead Sea in children with psoriasis vulgaris. More than 75% improvement in the Psoriasis Area and Severity Index was noted in 35.3% of the patients. None of the patients had side effects.
Nijmegen Breakage Syndrome Associated with Porokeratosis
Authors: WOLF ELIZABETH K. , SHWAYDER TOR A.
Published: February 2009

Abstract:  Nijmegen breakage syndrome (NBS) is a rare DNA repair disorder caused by mutations in the NBS‐1 gene (8q21). Patients with this autosomal recessive condition have characteristic facial features, microcephaly present at birth, immunodeficiency, predisposition to malignancy, ionizing radiation hypersensitivity, and growth retardation. We report a 12‐year‐old boy with NBS associated with porokeratosis; to our knowledge this association has not previously been reported.
How Well Do Social Ratings Actually Measure Corporate Social Responsibility?
Authors: Chatterji Aaron K. , Levine David I. , Toffel Michael W.
Published: February 2009

Ratings of corporations' environmental activities and capabilities influence billions of dollars of “socially responsible” investments as well as some consumers, activists, and potential employees. In one of the first studies to assess these ratings, we examine how well the most widely used ratings—those of Kinder, Lydenberg, Domini Research & Analytics (KLD)—provide transparency about past and likely future environmental performance. We find KLD “concern” ratings to be fairly good summaries of past environmental performance. In addition, firms with more KLD concerns have slightly, but statistically significantly, more pollution and regulatory compliance violations in later years. KLD environmental strengths, in contrast, do not accurately predict pollution levels or compliance violations. Moreover, we find evidence that KLD's ratings are not optimally using publicly available data. We discuss the implications of our findings for advocates and skeptics of corporate social responsibility as well as for studies that relate social responsibility ratings to financial performance.
Decrease in suicide among the individuals treated with antidepressants: a controlled study of antidepressants in suicide, Sweden 1995–2005
Authors: Isacsson G. , Holmgren A. , Ösby U. , Ahlner J.
Published: February 2009

Objective:  Ecological studies have demonstrated a substantial decrease in suicide in parallel with an increase in the use of antidepressants. Causality cannot, however, be inferred from such studies. The aim of this study was to test on the individual level the hypothesis that treatment with antidepressant medication has been a substantially contributing cause of the decrease in suicide.

Method:  Time trends in the detection of antidepressants and five ‘control medications’ in the forensic toxicological screening of 16 937 suicides and 33 426 controls in Sweden 1995–2005.

Results:  The expected number of antidepressant‐positive suicides in 2005 was 409 if the hypothesis was true and 603 if it was false. The observed number in 2005 was 420. The control medications were detected to the extent that was expected if not preventing suicide.

Conclusion:  The observed trend in the number of suicides with antidepressants was well predicted by the hypothesis that the increased use of antidepressants has been a substantially contributing cause of the decrease in suicide.
The subjective experience of taking antipsychotic medication: a content analysis of Internet data
Authors: Moncrieff J. , Cohen D. , Mason J. P.
Published: February 2009

Objective:  We explored the subjective effects associated with olanzapine, risperidone and older antipsychotics.

Method:  We conducted a content analysis of an Internet database of comments about prescribed medications.

Results:  We analysed 223 comments on risperidone, 170 on olanzapine and 46 relating to three older antipsychotics. The predominant subjective effects produced by all drugs consisted of sedation, cognitive impairment and emotional flattening or indifference. Connections appeared between these effects and Parkinsonian‐like symptoms with the older drugs, sexual impairment with risperidone and metabolic effects with olanzapine. The experience of akathisia was frequently linked to suicidal thoughts. Some respondents described how the drugs’ subjective effects helped to reduce symptoms of mania, psychosis and anxiety.

Conclusion:  The generalisability of Internet data is uncertain. However, the data suggest that adverse subjective effects play a central role in the experience of taking antipsychotic drugs and may be related to the drugs’ desired benefits.
Immunohistochemical detection of lymphovascular invasion with D2‐40 in melanoma correlates with sentinel lymph node status, metastasis and survival
Authors: Petersson Fredrik , Diwan A. Hafeez , Ivan Doina , Gershenwald Jeffrey E. , Johnson Marcella M. , Harrell Robyn , Prieto Victor G.
Published: February 2009

Using immunohistochemistry with anti‐D2‐40 for the detection of lymphovascular invasion (LVI‐IHC) in 74 cases of invasive melanoma, we found LVI in 23% (16/74) of the tumors. Data on sentinel lymph node (SLN) biopsy were available for 36 patients. Sixty‐seven percent (6/9) of patients with LVI‐IHC and 19% (5/27) without LVI‐IHC had positive SLN. Follow‐up data were available for 60 patients. Data on recurrence/metastasis were available for 60 patients. Twenty‐five percent (15/60) had LVI with immunohistochemistry. Fifty‐three percent (8/15) of these patients had “distant” metastasis or regional recurrence compared with 11% (5/45) in those without LVI‐IHC. Overall and disease‐specific survival was shorter for patients with LVI. In both the univariate and multivariate Cox proportional hazards regression models, LVI‐IHC in addition to ulceration was statistically significant with respect to overall survival. Specifically, in the reduced multivariate model, compared with patients with no LVI, patients with intratumoral LVI had a hazard ratio (HR) of 5.4 (95% CI 1.6–18.4), while patients with peritumoral LVI had a HR of 3.8 (95% CI 0.7–20.9). In addition, patients with ulceration had an increased hazard of 4.4 (95% CI 1.2–16.8).

For the first time, we herein show a positive correlation with LVI in melanoma detected with immunohistochemistry and distant metastasis, overall survival and disease‐free survival.
Prevalence of congenital malformations in Cross River and Akwa Ibom states of Nigeria from 1980–2003
Authors: Ekanem Theresa B. , Okon Doris E. , Akpantah Amabe O. , Mesembe Otu E. , Eluwa Mokutima A. , Ekong Moses B.
Published: February 2009

ABSTRACT  A retrospective study was conducted on the prevalence of congenital malformations in Cross River and Akwa Ibom states of Nigeria from 1980–2003. These states lie in the South‐South geopolitical zone of Nigeria. The aim of the study was to determine the percentage of occurrence of birth defects and provide reference data for this part of the country. Details of congenital malformations were compiled by reviewing the delivery register of the records departments of maternity sections of University of Calabar Teaching Hospital, St Luke's Hospital Anua and St Mary's Hospital Uruakpan. A total of 127 929 births were recorded, of which 452 cases of malformations were recorded. The anomalies recorded in the skeletal system were the highest with 132 cases (29.2%) detected. Other malformations were found to be associated with the central nervous system with 111 cases (24.6%) detected. Those associated with the urogenital system were found in 83 cases (18.4%). Congenital anomalies of the lip, palate and jaw were found in 56 cases (12.4%), while those of the eye and ear were found in 12 cases (2.7%). Those of the gastrointestinal tract were found in 29 cases (6.4%), while those of the respiratory and cardiovascular systems were found in 28 cases (6.2%) and in one case (0.2%), respectively. Fifteen cases (3.3%) were associated with chromosomal abnormalities, such as Down syndrome. However, these results do not provide a complete incidence of congenital malformations in the two states studies because most anomalies are not recorded in rural health and traditional birth centers.
3C 66B as a TeV radio galaxy
Authors: Tavecchio Fabrizio , Ghisellini Gabriele
Published: February 2009

The Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) Telescope collaboration reported the detection of a new very high energy source, MAGIC J0223+430, located close to the position of the blazar 3C 66A, considered a candidate TeV blazar since a long time. A careful analysis showed that the events with energies above 150 GeV are centred on the position of the Fanaro–Riley type I radio galaxy 3C 66B (at 6 arcmin from 3C 66A), with a probability of 95.4 per cent (85.4 per cent including systematic uncertainties) that the source is not related to 3C 66A. We present a model for the possible emission of 3C 66B based on the structured jet model already used to interpret the TeV emission of the radio galaxy M87. The model requires parameters similar to those used for M87 but a larger luminosity for the layer, to account for the more luminous TeV emission. We also show that the spectrum obtained by MAGIC can be interpreted as the combined emission of 3C 66B, dominating above ∼200 GeV, and 3C 66A. The high-energy emission from the latter source, being strongly attenuated by the interaction with the extragalactic background light, can only contribute at low energies. If we were to see the jet emission of 3C 66B at small viewing angles, we would see a spectral energy distribution closely resembling the one of S5 0716+714, a typical blazar.
EFFECT OF ENZYMATIC MACERATION ON SYNTHESIS OF HIGHER ALCOHOLS DURING MANGO WINE FERMENTATION
Authors: REDDY L.V.A. , REDDY O.V.S.
Published: February 2009

Mango is a popular and highly produced fruit in India. Wine from two mango cultivars Banginapalli and Totapuri was prepared and the mode of higher alcohols synthesis during wine fermentation was evaluated. Mangoes were peeled off and juice was extracted immediately after crushing (control) and also after 10 h of pectinase treatment. The recovered juice was allowed to ferment at 15 and 20C. During fermentation, higher alcohols and sugars were measured. Contents of all the higher alcohols analyzed increased during fermentation. More volatiles were observed in wine produced from Totapuri cultivar (358 ± 12.7 mg/L) than wine from Banginapalli cultivar (340 ± 10.5 mg/L). Pectinase treatment increased the synthesis of iso‐amylalcohol, 2‐phenyl ethanol, n‐propanol, n‐butanol and methanol during fermentation. Sensory evaluation scores of wine correlated to the sum of higher alcohols. The results of the present study suggest that the pectinase treatment increases the mango juice yield and results in better wine sensory quality.

PRACTICAL APPLICATIONS

Nowadays, the number of wine consumers is increasing rapidly all over the world. In order to meet the demand, researchers are developing alternative wine producing technologies. In the present study, we made an attempt to produce wine from mango, the king fruit of world. The main objectives of this study are to increase the quality and quantity of mango juice for wine production and evaluate the aroma compounds kinetic parameters during wine fermentation. This study also provides an adequate process for both juice and wine production from mango and other tropical fruits. The findings regarding pectinase treatment, formation of major volatile compounds and sensory evaluation can be valuable references to the wine industry.
Consumer Self‐Confidence in Searching for Information
Authors: LOIBL CÄZILIA , CHO SOO HYUN , DIEKMANN FLORIAN , BATTE MARVIN T.
Published: February 2009

Consumer behavior is often driven by the extent to which consumers feel confident regarding their decisions, which frequently hinge, especially in high‐stakes situations, on their information search. This article examines a multidimensional self‐confidence concept to explore how consumer self‐confidence influences information search. Findings of a mail survey document that high‐confidence consumers engage in more intensive search activities and that demographic patterns shape consumer self‐confidence scores. The findings empirically support a multidimensional measurement of self‐confidence to predict search behavior and suggest avenues to enhance the self‐confidence needed to produce positive marketplace experiences.
An Overview of Terra Mission Results Related to the Carbon Cycle
Authors: Imhoff Marc L. , Wolfe Robert , Diner David J. , Chopping Mark , Kahn Ralph , Salomonson Vincent , Gille John , Drummond James , Edwards David , Loeb Norm , Wielicki Bruce , Abrams Michael , Eng Bjorn , Tsay Si‐Chee , Ranson K. Jon
Published: February 2009

Launched in December 1999 as the Earth Observing System's flagship observatory, the Terra Mission (formerly EOS AM‐1) carries a suite of five instruments that collect comprehensive global measurements of earth's atmosphere, cryosphere, lands, and oceans. One of the mission's science goals is the collection of data that will enable a better quantitative understanding of earth's carbon cycle through direct observation of atmospheric constituents and the provision of spatially explicit information about biophysical surface properties useful for modeling. In this article, highlights of the mission's use of five main instruments (ASTER, CERES, MISR, MODIS, and MOPITT) to address various aspects of the carbon cycle are reviewed, using examples of earth's photosynthetic production on land, vegetation structure and ecosystem response, and the extent and frequency of fires and their contribution of aerosols and carbon emissions to the atmosphere.
El impacto macroeconómico de la reforma del sistema de reparto: el caso portugués
Authors: Garcia Maria Teresa Medeiros , Lopes Emídio Graça
Published: February 2009

Resumen  Este artículo analiza el impacto que tendrán varias alternativas de reforma en la sostenibilidad financiera del régimen de pensiones de la seguridad social y en una serie de factores macroeconómicos. Se utiliza el modelo HERPOR para examinar las posibles repercusiones que tendrán las reformas paramétricas del vigente sistema de reparto, así como las repercusiones de una reforma sistémica. El artículo concluye que el primer tipo de reformas es suficiente para garantizar la sostenibilidad financiera, aunque debería ir acompañado de medidas de creación de empleo. También afirma que un sistema plenamente prefinanciado no parece ser una opción viable para que los dirigentes políticos rediseñen los sistemas de pensiones de la seguridad social, ya que entrañará elevados costes de transición.
On the sensitivity of patient‐specific IMRT QA to MLC positioning errors
Authors: Yan Guanghua , Liu Chihray , Simon Thomas A , Peng Lee‐Cheng , Fox Christopher , Li Jonathan G
Published: February 2009

Accurate multileaf collimator (MLC) leaf positioning plays an essential role in the effective implementation of intensity modulated radiation therapy (IMRT). This work evaluates the sensitivity of current patient‐specific IMRT quality assurance (QA) procedures to minor MLC leaf positioning errors. Random errors of up to 2 mm and systematic errors of and in MLC leaf positions were introduced into 8 clinical IMRT patient plans (totaling 53 fields). Planar dose distributions calculated with modified plans were compared to dose distributions measured with both radiochromic films and a diode matrix. The agreement between calculation and measurement was evaluated using both absolute distance‐to‐agreement (DTA) analysis and γ index with and criteria. It was found that both the radiochromic film and the diode matrix could only detect systematic errors on the order of 2 mm or above. The diode array had larger sensitivity than film due to its excellent detector response (such as small variation, linear response, etc.). No difference was found between DTA analysis and γ index in terms of the sensitivity to MLC positioning errors. Higher sensitivity was observed with than with in general. When using the diode array and criterion, the IMRT QA procedure showed strongest sensitivity to MLC position errors and, at the same time, achieved clinically acceptable passing rates. More accurate dose calculation and measurement would further enhance the sensitivity of patient‐specific IMRT QA to MLC positioning errors. However, considering the significant dosimetric effect such MLC errors could cause, patient‐specific IMRT QA should be combined with a periodic MLC QA program in order to guarantee the accuracy of IMRT delivery.

PACS numbers: 87.50.Gi, 87.52.Df, 87.52.Px, 87.53.Dq, 87.53.Tf, 87.53.Kn, 87.56.Fc
Nanoelectrospray versus electrospray in chiral analysis by the kinetic method
Authors: Ranc Václav , Havlíček Vladimír , Bednář Petr , Lemr Karel
Published: February 2009

Electrospray ionization generates trimeric diastereoisomeric clusters as the first important step in chiral analysis by mass spectrometry using the Cooks′ kinetic method. Cu2+ and L-tryptophan were used as a central metal and as a chiral reference ligand, respectively. The comparison of electrospray and nanoelectrospray showed that although the electrospray system was generally more robust, the application of nanoelectrospray was essential for performing successful analysis in some cases, especially for real samples. Basically, no significant differences between the ion sources were observed for model samples of analytes (isoleucine, ephedrine, phenylalanine) without interfering matrix. On the other hand, model samples containing sodium chloride and a buffer containing a real sample (drug formulation Mucoseptonex E in which D-ephedrine is the active substance) could not be analyzed using ESI, whereas nano-ESI gave satisfactory results. An explanation is based on the differences of ionization processes occurring in the compared sources.
Population or Stock Structure of Lake Whitefish, Coregonus clupeaformis, in Northern Lake Michigan as Assessed by Isozyme Electrophoresis
Authors: Imhof Mark , Leary Robb , Booke Henry E.
Published: February 2009

Electrophoretic analysis of three polymorphic isozymes (lactate, malate, and glycerol-3-phosphate dehydrogenases) from lake whitefish, Coregonus clupeaformis, indicated that at least four populations exist in northern Lake Michigan. Cluster analysis of Nei genetic identity indices revealed much temporal and spatial overlap among population ranges. The overlap did not appear complete since the LDH A allele exhibited clinal variation with increasing frequency from south to north. Because population ranges overlap spatially and temporally, commercial catches are likely to contain fish from more than one population.Key words: population (stock), isozyme electrophoresis, lake whitefish, Lake Michigan
Discrete versus average integration in shear assessment of spiral links
Authors: Jaafar Kamal
Published: February 2009

Common transverse reinforcement of reinforced concrete members with circular cross section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both a shear resister and confining enabler for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required.
Experimental investigation of the ultimate shear resistance of end web panels in steel girder bridges
Authors: Au Alexander , Lam Clifford , Tharmabala Bala
Published: February 2009

An experimental study was recently undertaken by the Ontario Ministry of Transportation to investigate the effect of tension field anchorage on the ultimate shear resistance in end panels of steel girders. Four reduced-scale models were fabricated with one end stiffened with transverse stiffeners to provide anchorage for the tension field while the other end was unstiffened (unanchored). The models were instrumented and loaded until shear failure occurred. The main findings are (a) post-buckling tension field stresses were developed in the unanchored end-panels, (b) the magnitude of the tension field component was affected by the web slenderness ratio, and (c) the results showed inconsistencies in the Canadian Highway Bridge Design Code procedure for calculating ultimate shear resistance of steel girders.
Seismic design and performance evaluation of steel-frame buildings designed using the 2005 National building code of Canada
Authors: Yousuf Md , Bagchi Ashutosh
Published: February 2009

The seismic design provisions in the current edition of the National building code of Canada significantly differ from those in the earlier version of the code . Although the code has moved from the earlier prescriptive provisions towards a more performance-based design, such design principles have not yet been fully implemented. In the present work, four ductile steel moment-resisting frame buildings with heights of 5, 10, 15, and 20 storeys, were designed for Vancouver using the newer code, and their performances were studied to determine the level of seismic protection implied in the code. Synthesized and scaled real ground motion records were used to evaluate the nonlinear dynamic response of these structures. Although the buildings achieved the collapse prevention performance objective of the code, variations in evaluated performance parameters for the different buildings were observed. Also, building performance was found to be affected by the presence of infill walls, as well as by the nature of selected ground motion records and the methods used to scale them to Vancouver uniform hazard spectra.
Utilization of white cement bypass dust as filler in asphalt concrete mixtures
Authors: Ramadan Khaled Z. , Ashteyat Ahmed M.
Published: February 2009

This research was carried out to investigate potential reuses of white cement bypass dust (WCBPD) in the Hashemite Kingdom of Jordan. For this purpose, five different asphalt concrete mixtures were prepared using lime mineral filler (control), 2%, 4%, 6%, and 8% WCBPD substitution for lime mineral filler (LMF). The mixtures were subjected to Marshall testing. Results indicated that the substitution of 2% WCBPD for LMF essentially produced almost the same optimum bitumen content (OBC) as the control mixtures (5.5% by weight of aggregate). The substitution of 4% WCBPD slightly increased the OBC to 5.7% by weight of aggregate without any significant negative effect on asphalt concrete properties (stability, flow, voids in mineral aggregates (VMA), and percent of air voids (Pav)). However, further increase in the substitution ratios (6% and 8%) WCBPD was associated with an increase in the OBC to 6.1% and 6.2%, respectively, which makes them uneconomical mixtures. Thus, 4% WCBPD substitution for LMF would be the optimum used in asphalt paving mixtures.
Hydraulic optimization of a combined sewer overflow (CSO) storage facility using numerical and physical modelingA paper submitted to the Journal of Environmental Engineering and Science.
Authors: He Cheng , Marsalek Jiri
Published: February 2009

A commercially available 3-D computational fluid dynamics (CFD) model (STAR-CD) was used to investigate capacity upgrading options for a combined sewer overflow (CSO) facility of inadequate capacity. The numerical model was verified against the data collected in two physical models. The need for verifying the CFD model was given by the complexity of the CSO facility, which comprises several interconnected tanks. The verified numerical model was then applied to analyze hydraulic conditions in the whole facility for major structural modifications with the aim of reducing or eliminating untreated overflows from the facility. Many scenarios were proposed and tested in the study and the two most promising structural modifications, scenarios 1 and 2, are presented in the paper. Both appeared to meet the design condition of increasing the facility capacity to 60 m3/s, but better performing scenario 1 would be significantly more costly to implement than scenario 2. Even though the study focused on a particular CSO facility, hydraulic conditions in the studied facility represent general flow conditions in typical CSO or stormwater settling facilities and, therefore, the numerical modeling methods used are applicable to solving a wide range of hydraulic problems encountered at similar facilities.
CONSTRUCTING OPTIMAL HIGHWAYS
Authors: AHN HEE-KAP , ALT HELMUT , ASANO TETSUO , BAE SANG WON , BRASS PETER , CHEONG OTFRIED , KNAUER CHRISTIAN , NA HYEON-SUK , SHIN CHAN-SU , WOLFF ALEXANDER
Published: February 2009

For two points p and q in the plane, a straight line h, called a highway, and a real v > 1, we define the travel time (also known as the city distance) from p and q to be the time needed to traverse a quickest path from p to q, where the distance is measured with speed v on h and with speed 1 in the underlying metric elsewhere.

Given a set S of n points in the plane and a highway speed v, we consider the problem of finding a highway that minimizes the maximum travel time over all pairs of points in S. If the orientation of the highway is fixed, the optimal highway can be computed in linear time, both for the L1- and the Euclidean metric as the underlying metric. If arbitrary orientations are allowed, then the optimal highway can be computed in O(n2 log n) time. We also consider the problem of computing an optimal pair of highways, one being horizontal, one vertical.
TERMINATION OF ABSTRACT REDUCTION SYSTEMS
Authors: DAWSON JEREMY E. , GORÉ RAJEEV
Published: February 2009

We present a general theorem capturing conditions required for the termination of abstract reduction systems. We show that our theorem generalises another similar general theorem about termination of such systems. We apply our theorem to give interesting proofs of termination for typed combinatory logic. Thus, our method can handle most path-orderings in the literature as well as the reducibility method typically used for typed combinators. Finally we show how our theorem can be used to prove termination for incrementally defined rewrite systems, including an incremental general path ordering. All proofs have been formally machine-checked in Isabelle/HOL.
A UNIVERSE OF STRICTLY POSITIVE FAMILIES
Authors: MORRIS PETER , ALTENKIRCH THORSTEN , GHANI NEIL
Published: February 2009

In order to represent, compute and reason with advanced data types like lists with a fixed length, finite sets or well scoped λ-terms one must go beyond the traditional treatment of data types as being inductive types and, instead, consider them as inductive families, or more precisely Strictly Positive Families (SPFs). We have previously shown that the grammar of strictly positive types (SPT) can be given as an inductively defined family. In the present paper we go one step further an show that the universe of SPFs can be encoded as an SPF. We show that SPFs can be used to represent and compute with a variety of advanced data types and that generic programs can be naturally written over the universe of SPFs.
CHALLENGES AND PROGRESS IN III-V MOSFETs FOR CMOS CIRCUITS
Authors: OKTYABRSKY SERGE , YAKIMOV MICHAEL , TOKRANOV VADIM , KAMBHAMPATI RAMA , BAKHRU HASSARAM , KOVESHNIKOV SERGEI , TSAI WILMAN , ZHU FENG , LEE JACK
Published: February 2009

An overview of III-V MOSFET technological challenges in comparison to well-established heterostructure-based FET technologies is presented with an emphasis on required properties and possible solutions. Possible approaches to achieve thermodynamically stable high- k gate stack with low interface trap density are reviewed, followed with our results on amorphous Si interface passivation layer (IPL) in-situ deposited on top of GaAs or strained InGaAs MOSFET channels grown by molecular beam epitaxy. Main issues of Si IPL, namely increased equivalent oxide thickness due to IPL oxidation and Si diffusion into the semiconductor channel, are addressed using an in-situ deposited HfO 2 with ultrathin (down to 0.25 nm) Si IPL and controlling its bonding state at the interface. Enhancement mode inversion-type MOSFET with HfO 2 high- k oxide is demonstrated. The device employs amorphous Si interface passivation layer, sputter-deposited high- k oxide and metal TaN gate and modulation p-doped GaAs / AlGaAs heterostructure with inversion n -channel formed at the interface with the oxide. The MOSFET with equivalent oxide thickness of 3.7 nm and long 100 μm channel have maximum DC transonductance of 0.9 mS/mm, Ion/Ioff = 2×104 (at low Ioff of 30 nA) and effective channel mobility exceeding 1000 cm2/V-s at sheet electron density <2×1012 cm-2.
AN EFFICIENT NUMERICAL METHOD OF DC MODELING FOR POWER MOSFET, MESFET AND AlGaN/GaN HEMT
Authors: RAHMAN TOUHIDUR , HUQUE MOHAMMAD A. , ISLAM SYED K.
Published: February 2009

In this paper, an efficient numerical model applicable for wide varieties of long channel field-effect transistors (MOSFET, MESFET, HEMT, etc.) is developed. A set of available data is used to calculate the model parameters and another set of data is used to verify the accuracy of the model. This model provides a single expression that is applicable for the entire range of device biasing and can predict the output parameters with less than 1% error compared to the experimental results. Lagrange polynomial, the highest degree of polynomial for any given set of data, is used to derive the model from available data. This method is efficient in the sense that it can be derived from a limited number of experimental data and since it uses only one equation for entire range of the device operation hence its computational cost is also small.
THE DEPOSITION AND CONTROL OF SELF ASSEMBLED SILICON NANO ISLANDS ON CRYSTALLINE SILICON
Authors: KIEBACH RAGNAR , YU ZHENRUI , ACEVES-MIJARES MARIANO , BIAN DONGCAI , DU JINHUI
Published: February 2009

The formation of nano sized Si structures during the annealing of silicon rich oxide (SRO) films was investigated. These films were synthesized by low pressure chemical vapor deposition (LPCVD) and used as precursors, a post-deposition thermal annealing leads to the formation of Si nano crystals in the SiO 2 matrix and Si nano islands ( Si nI ) at c-Si /SRO interface. The influences of the excess Si concentration, the incorporation of N in the SRO precursors, and the presence of a Si concentration gradient on the Si nI formation were studied. Additionally the influence of pre-deposition substrate surface treatments on the island formation was investigated. Therefore, the substrate surface was mechanical scratched, producing high density of net-like scratches on the surface. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize the synthesized nano islands. Results show that above mentioned parameters have significant influences on the Si nIs . High density nanosized Si islands can epitaxially grow from the c-Si substrate. The reported method is very simple and completely compatible with Si integrated circuit technology.
FLUCTUATIONS AND ULTRAFAST PROCESSES IN VOLTAGE-BIASED TWO-DIMENSIONAL CHANNELS
Authors: MATULIONIS ARVYDAS
Published: February 2009

Hot-electron fluctuation techniques were developed for experimental investigation of picosecond and subpicosecond electronic and phononic processes in voltage-biased 2DEG channels of interest for microwave low-noise and high-power transistors. Examples illustrate real-space transfer, hot-electron energy relaxation, and occupancy relaxation of hot-phonon modes. The pioneering results on hot-electron energy relaxation and hot-phonon lifetime are confirmed by time-resolved response experiments. The fluctuation technique for measuring the hot-phonon lifetime as a function of the hot-phonon temperature is unique, no datum has been reported for comparison as yet.
NON-IDEAL CURRENT TRANSPORT IN HETEROSTRUCTURE FIELD EFFECT TRANSISTORS
Authors: KOUDYMOV ALEXEI , SHUR MICHAEL
Published: February 2009

We describe a new analytical model of a Heterostructure Field Effect Transistors (HFETs) that accounts for electron trapping in the gate-drain spacing of the device and for related non-ideal device behavior. Under conditions of a very strong trapping, the electron velocity saturates outside the gate, in the trapping region, and the negative trapped charge leads to relatively large differential output conductance at the drain voltages exceeding the knee voltage. Also under the conditions of severe trapping, the negative trapped charge leads to the positive offset of the output current-voltage (I-V) characteristic. The model describes quite well numerous experimental data for passivated and unpassivated AlGaN / GaN HFETs with and without field plates (FP) under different bias conditions.
THZ DETECTION BY FIELD-EFFECT TRANSISTORS IN MAGNETIC FIELDS: SHALLOW WATER VS DEEP WATER MECHANISM OF ELECTRON PLASMA INSTABILITY
Authors: Sakowicz M. , Łusakowski J. , Karpierz K. , Grynberg M. , Knap W. , Köhler K. , Valušis G. , Gołaszewska K. , Kamińska E. , Piotrowska A.
Published: February 2009

Detection of THz radiation by a high electron mobility (HEMT) GaAs / GaAlAs transistor was investigated at 4 K as a function of the magnetic field B. The detection signal (a source - drain photovoltage appearing as a response to THz radiation) was found to be periodic in B-1, i.e., it showed Shubnikov - de Haas oscillations. A Fourier transform of the signal showed a large amplitude component independent of the gate voltage, and a small amplitude component dependent on it. This shows that a HEMT response to the radiation cannot be described either by a plasma instability in gated ("shallow water") or in ungated ("deep water") parts of the channel, but rather by a response of the channel as a whole. This is in a good correspondence with recent experimental evidence of antenna effects in detection of radiation by HEMTs and advanced theoretical models of instability of coupled gated - ungated plasma in HEMTs.
HOT-ELECTRON TRANSPORT IN QUANTUM-DOT PHOTODETECTORS
Authors: CHIEN L. H. , SERGEEV A. , VAGIDOV N. , MITIN V.
Published: February 2009

Employing Monte-Carlo simulations we investigate effects of an electric field on electron kinetics and transport in quantum-dot structures with potential barriers created around dots via intentional or unintentional doping. Results of our simulations demonstrate that the photoelectron capture is substantially enhanced in strong electric fields and this process has an exponential character. Detailed analysis shows that effects of the electric field on electron capture in the structures with barriers are not sensitive to the redistribution of electrons between valleys and these effects are not related to an increase of drift velocity. Most data find adequate explanation in the model of hot-electron transport in the potential relief of quantum dots. Electron kinetics controllable by potential barriers and an electric field may provide significant improvements in the photoconductive gain, detectivity, and responsivity of photodetectors.
SCALABLE SINGLE PHOTON DETECTOR FOR TERAHERTZ AND INFRARED APPLICATIONS
Authors: WU DONG HO , MATIS BERNARD R. , BUSSMAN KONRAD
Published: February 2009

We have developed a detector that can detect single photons at terahertz frequencies. The detector is based on quantum dot and single electron transistor technology, and the structure is scalable. One can scale the detector of nearly the same structure to be used for different frequencies. Our numerical calculation, which was performed along with our experimental efforts, indicates that the same detector structure can be used for millimeter-wave and far-infrared frequencies.
MICROBOLOMETERS FABRICATED WITH SURFACE MICROMACHINING WITH a-Si-Ge: H THERMO-SENSING FILMS
Authors: MORENO MARIO , KOSAREV ANDREY , TORRES ALFONSO , AMBROSIO ROBERTO
Published: February 2009

In this work we present the process flow for the fabrication of un-cooled IR detectors employing surface micro-machining techniques over silicon substrates. These detectors are based on thin films deposited by plasma at low temperatures. The thermo sensing film used is an intrinsic a - Si x Ge 1- x : H film, which has demonstrated a very high temperature coefficient of resistance (TCR), and a moderated resistivity, these properties are better than those of the a - Si : H intrinsic film, which is commonly used in commercial IR devices. Two device configurations have been designed and fabricated, labeled planar and sandwich. The former is the configuration commonly used in commercial micro-bolometers, while the latter is proposed in order to reduce the high cell resistance observed in this kind of devices, without the necessity of doping the intrinsic film, which results in a decrement of the TCR and therefore in responsivity. Finally some performance characteristics of the devices studied are discussed in comparison with data reported in literature.
ENHANCING INTERNET NETWORK RELIABILITY WITH INTEGRATED FRAMEWORK OF MULTI-OBJECTIVE GENETIC ALGORITHM AND MONTE CARLO SIMULATION
Authors: KIM JONG-RYUL , KIM DOHOON
Published: February 2009

This paper presents a combined framework of Multi-Objective Generic Algorithm (MOGA) and Monte Carlo Simulation (MCS) in order to improve backbone topology by leveraging the Virtual Link (VL) system in an hierarchical Link-State (LS) routing domain. Given that the sound backbone topology structure has a great impact on the overall routing performance in a hierarchical LS domain, the importance of this research is evident. The proposed decision model is to find an optimal configuration of VLs that properly meets two-pronged engineering goals in installing and maintaining VLs: i.e., operational costs and network reliability. The experiment results clearly indicates that it is essential to the effective operations of hierarchical LS routing domain to consider not only engineering aspects but also specific benefits from systematical layout of VLs, thereby presenting the validity of the decision model and MOGA with MCS.
PROCESSING OF NANO-CRYSTALLITE SPINEL FERRITE PREPARED BY CO-PRECIPITATION METHOD
Authors: MATHUR P. , THAKUR A. , SINGH M.
Published: February 2009

Mn 0.4 Cu 0.4 Zn 0.2 Fe ferrite was synthesized by soft chemical approach called co-precipitation technique. The ferrite powder was calcined, compacted and sintered at 700°C and 800°C for 3 h. The initial permeability, density, grain size, Curie temperature and dc resistivity have been studied. X-ray diffraction (XRD) method confirmed the sample to be a single-phase spinel structure without unreacted constituents. The particle size was calculated from XRD spectrum using Scherrer's formula and found to be ~55 nm. Then, nanoparticles were observed with tunneling electron microscopy (TEM). Further, scanning electron micrograph (SEM) also confirmed nano-phase and the uniformity of the particles. The initial permeability values do not exhibit much variation with temperature, except near Curie temperature, where it falls sharply. The initial permeability is found to increase with the increase in sintering temperature. This is attributed to the increase in the grain size. Calculation of activation energy indicates that the given ferrite is p-type semiconductor. Mössbauer study of these samples shows superparamagnetic behavior, which also confirms the formation of nano-particles. Possible models and mechanisms contributing to these processes have been discussed.
ANALYSIS OF ANISOTROPIES OF MAGNETIC HYSTERESIS AND MAGNETIC ALIGNMENT IN GRAIN ALIGNED Yb1Ba2Cu3O7-δ
Authors: AHMAD DAWOOD , KIM G. C. , LEE J. H. , KO ROCK-KIL , PARK INSUK , KIM Y. C.
Published: February 2009

We evaluated the magnetic alignment and superconducting magnetic anisotropies of high-Tc superconductor Yb 1 Ba 2 Cu 3 O 7-δ by both X-ray diffraction and magnetization measurements. The sample was grain aligned under a high magnetic field of 6 T. X-ray diffraction pattern revealed normal alignment in Yb -123 by showing the c axis aligned perpendicular to the magnetic field. At low temperatures, magnetic hysteresis ΔM with magnetic field perpendicular to a–b plane is larger than magnetic hysteresis parallel to a–b plane. A crossover was observed at higher temperature in magnetic hystereses, i.e., ΔM⊥a - b < ΔM‖a - b at certain applied field. This crossover can be explained due to difference in vortex structure along both field directions.
A NEW TECHNIQUE FOR CLASSIFICATION OF DIGITAL SIGNAL TYPES
Authors: EBRAHIMZADEH ATAOLLAH , RANJBAR ABOLFAZL , ARDEBLILPOUR MEHRDAD
Published: February 2009

Classification of the communication signals has seen under increasing demands. In this paper, we present a new technique that identifies a variety of digital communication signal types. This technique utilizes a radial basis function neural network (RBFN) as the classifier. Swarm intelligence, as an evolutionary algorithm, is used to construct RBFN. A combination of the higher-order moments and the higher-order cumulants up to eight are selected as the features of the considered digital signal types. In conjunction with RBFN, we have used k-fold cross-validation to improve the generalization potentiality. Simulation results show that the proposed technique has high performance for classification of different communication signals even at very low signal-to-noise ratios.
EXPLOITING TEMPORAL LOCALITY FOR ENERGY EFFICIENT MEMORY MANAGEMENT
Authors: SEO EUISEONG , MAENG SEUNGRYOUL , LIM DONGHYOUK , LEE JOONWON
Published: February 2009

Memory is becoming one of the major power consumers in computing systems. Therefore, energy efficient memory management is essential. Modern memory systems employ sleep states for energy saving. To utilize this feature, existing research activities have concentrated on increasing spatial locality to deactivate as many blocks as possible. However, they did not count the unexpected activation of memory blocks due to cache eviction of deactivated tasks. In this paper, we suggest a software-based power state management scheme for memory, which exploits temporal locality to relieve the energy loss from the unexpected activation of memory blocks from cache eviction. The suggested scheme SW-NAP makes a memory block remain deactivated during a certain tick, which has no cache miss over the block. The evaluation shows that SW-NAP is 50% better than PAVM, which is an existing software scheme, and worse than PMU, which is another approach based on the specialized hardware by 20%. We also suggest task scheduling policies that increase the effectiveness of SW-NAP and they saved up to 7% additional energy.