bluuebunny/crossref_metadata_2025 huggingface dataset:
Outbreak Caused by NDM-1- and RmtB-Producing Escherichia coli in Bulgaria
Authors: Poirel Laurent , Savov Encho , Nazli Arzu , Trifonova Angelina , Todorova Iva , Gergova Ivanka , Nordmann Patrice
Published: February 2014

Twelve consecutive carbapenem-resistant
Escherichia coli
isolates were recovered from patients (infection or colonization) hospitalized between March and September 2012 in different units at a hospital in Bulgaria. They all produced the carbapenemase NDM-1 and the extended-spectrum-β-lactamase CTX-M-15, together with the 16S rRNA methylase RmtB, conferring high-level resistance to all aminoglycosides. All those isolates were clonally related and belonged to the same sequence type, ST101. In addition to being the first to identify NDM-producing isolates in Bulgaria, this is the very first study reporting an outbreak of NDM-1-producing
E. coli
in the world.
Fluoroquinolone-Resistant Pneumococci: Dynamics of Serotypes and Clones in Spain in 2012 Compared with Those from 2002 and 2006
Authors: Domenech Arnau , Tirado-Vélez Jose M. , Fenoll Asunción , Ardanuy Carmen , Yuste Jose , Liñares Josefina , de la Campa Adela G.
Published: February 2014

In Spain, rates of ciprofloxacin resistance in pneumococci were low during the last decade (2.6% in 2002 and 2.3% in 2006). In 2012, the rate remained at 2.3%, equivalent to 83 of 3,621 isolates. Of the 83 resistant isolates, 15 showed a low level (MIC of 4 to 8 μg/ml) and 68 a high level (MIC of 16 to 128 μg/ml) of ciprofloxacin resistance. Thirteen low-level-resistant isolates had single changes in ParC, one had a single ParE change, and one did not present any mutations. High-level-resistant isolates had GyrA changes plus additional ParC and/or ParE changes: 51, 15, and 2 isolates had 2, 3, or 4 mutations, respectively. Although 24 different serotypes were observed, 6 serotypes accounted for 51.8% of ciprofloxacin-resistant isolates: 8 (14.5%), 19A (10.8%), 11A (7.2%), 23A (7.2%), 15A (6.0%), and 6B (6.0%). A decrease in pneumococcal 7-valent conjugate vaccine (PCV7) serotypes was observed from 2006 (35.7%) to 2012 (16.9%), especially of serotype 14 (from 16.3% to 2.4%;
P
< 0.001). In comparison with findings in 2006, multidrug resistance was greater in 2012 (
P
= 0.296), mainly due to the increased presence and/or emergence of clonal complexes associated with non-PCV7 serotypes: CC63 expressing serotypes 8, 15A, and 19A; CC320 (with serotype 19A); and CC42 (with serotype 23A). Although rates of ciprofloxacin resistance remained low and stable throughout the last decade, changes in serotype and genotype distributions were observed in 2012, notably the expansion of a preexisting multidrug-resistant clone, CC63, and the emergence of the CC156 clone expressing serotype 11A.
3′-Nucleotidase/Nuclease Activity Allows Leishmania Parasites To Escape Killing by Neutrophil Extracellular Traps
Authors: Guimarães-Costa Anderson B. , DeSouza-Vieira Thiago S. , Paletta-Silva Rafael , Freitas-Mesquita Anita Leocádio , Meyer-Fernandes José Roberto , Saraiva Elvira M.
Published: February 2014

Leishmaniasis is a widespread neglected tropical disease caused by parasites of the
Leishmania
genus. These parasites express the enzyme 3′-nucleotidase/nuclease (3′NT/NU), which has been described to be involved in parasite nutrition and infection. Bacteria that express nucleases escape the toxic effects of neutrophil extracellular traps (NETs). Hence, we investigated the role of 3′NT/NU in
Leishmania
survival of NET-mediated killing. Promastigotes of
Leishmania infantum
were cultured in high-phosphate (HP) or low-phosphate (LP) medium to modulate nuclease activity. We compared the survival of the two different groups of
Leishmania
during interaction with human neutrophils, assessing the role of neutrophil extracellular traps. As previously reported, we detected higher nuclease activity in parasites cultured in LP medium. Both LP and HP promastigotes were capable of inducing the release of neutrophil extracellular traps from human neutrophils in a dose- and time-dependent manner. LP parasites had 2.4 times more survival than HP promastigotes. NET disruption was prevented by the treatment of the parasites with ammonium tetrathiomolybdate (TTM), a 3′NT/NU inhibitor. Inhibition of 3′NT/NU by 3′-AMP, 5′-GMP, or TTM decreased promastigote survival upon interaction with neutrophils. Our results show that
Leishmania infantum
induces NET release and that promastigotes can escape NET-mediated killing by 3′-nucleotidase/nuclease activity, thus ascribing a new function to this enzyme.
Think global, act local: chronic dysuria and sterile pyuria in an Eritrean-American woman
Authors: Rutishauser Rachel Lena , Langelier Charles , Baxi Sanjiv M , Hanks Douglas , Chin-Hong Peter
Published: February 2014

A 70-year-old female Eritrean immigrant living in the USA presented with classic findings of genitourinary (GU) tuberculosis (TB), including risk of tuberculosis exposure based on country of origin, chronic urinary tract symptoms and persistent sterile pyuria despite antibacterial therapy. Furthermore, this patient had the hallmark radiographical findings of ureteral stricture, a dilated pelvic calyceal system, hydroureteronephrosis and bladder wall thickening, as well as a bladder wall biopsy that revealed granulomatous disease. The patient was evaluated multiple times over the course of 3 years in outpatient and inpatient medical settings before a diagnosis was made and appropriate treatment initiated. As with many cases of GU TB, a protracted diagnosis allowed for advanced disease progression and significant morbidity from obstructive uropathy and chronic kidney disease.
A surprising diagnosis: metastatic prostate cancer causing cervical lymphadenopathy
Authors: Lad Meher , Sharma Anita , Patten Darren K
Published: February 2014

Cervical lymphadenopathy as an initial presentation for metastatic prostate cancer has been rarely described. Less than 30 cases have been published in medical literature whereby a lymph node biopsy revealed immunoreactivity for prostate-specific antigen (PSA) diagnosing metastatic prostate cancer. We present a unique scenario whereby an asymptomatic patient with previous high-risk gastric cancer presented to clinic with cervical lymphadenopathy. A hunt for a recurrence ensued to no avail and imaging of the head and neck showed no hint of a primary malignancy in those regions. A lymph node biopsy was undertaken which showed elements suggesting metastatic prostate cancer. The patient developed symptoms of urinary outflow obstruction shortly afterwards. Blood tests revealed a very high PSA and a bone scan showed widespread bony metastasis. He was started on androgen deprivation therapy with an improvement of his PSA and symptoms. A regular clinic follow-up has shown stable disease.
Topical timolol for treatment of epistaxis in hereditary haemorrhagic telangiectasia associated with bradycardia: a look at CYP2D6 metabolising variants
Authors: Epperla Narendranath , Brilliant Murray H , Vidaillet Humberto
Published: February 2014

A 59-year-old man presented to the emergency department with lightheadedness. He had started intranasal administration of ophthalmic timolol for the prevention of epistaxis associated with hereditary haemorrhagic telangiectasia approximately 3 weeks earlier with excellent response. His heart rate was about half its normal rate, an ECG revealed sinus bradycardia, and it was determined he had significant cardiac issues in his family history. Essentially all other tests were normal. The discontinuation of the intranasal use of timolol resolved any further episodes of lightheadedness and bradycardia. It was determined through genetic testing that he is an intermediate metaboliser of CYP2D6, the main enzyme contributing to the metabolism of timolol. This explains the development of the bradycardia after intranasal timolol use. The metabolising variants of CYP2D6 need to be considered when prescribing medications metabolised by this enzyme, so possible adverse effects can be avoided.
Collapsed scrums and collision tackles: what is the injury risk?
Authors: Roberts Simon P , Trewartha Grant , England Mike , Stokes Keith A
Published: February 2014

Aim

To establish the propensity for specific contact events to cause injury in rugby union.

Methods

Medical staff at participating English community-level rugby clubs reported any injury resulting in the absence for one match or more from the day of the injury during the 2009/2010 (n=46), 2010/2011 (n=67) and 2011/2012 (n=76) seasons. Injury severity was defined as the number of matches missed. Thirty community rugby matches were filmed and the number of contact events (tackles, collision tackles, rucks, mauls, lineouts and scrums) recorded.

Results

Of 370 (95% CI 364 to 378) contact events per match, 141 (137 to 145) were tackles, 115 (111 to 119) were rucks and 32 (30 to 33) were scrums. Tackles resulted in the greatest propensity for injury (2.3 (2.2 to 2.4) injuries/1000 events) and the greatest severity (16 (15 to 17) weeks missed/1000 events). Collision tackles (illegal tackles involving a shoulder charge) had a propensity for injury of 15 (12.4 to 18.3) injuries/1000 events and severity was 92 (75 to 112) weeks missed/1000 events, both of which were higher than any other event. Additional scrum analysis showed that only 5% of all scrums collapsed, but the propensity for injury was four times higher (2.9 (1.5 to 5.4) injuries/1000 events) and the severity was six times greater (22 (12 to 42) weeks missed/1000 events) than for non-collapsed scrums.

Conclusions

Injury prevention in the tackle should focus on technique with strict enforcement of existing laws for illegal collision tackles. The scrum is a relatively controllable event and further attempts should be made to reduce the frequency of scrum collapse.
Association between population prevalence of smoking and incidence of meningococcal disease in Norway, Sweden, Denmark and the Netherlands between 1975 and 2009: a population-based time series analysis
Authors: Norheim Gunnstein , Sadarangani Manish , Omar Omar , Yu Ly-Mee , Mølbak Kåre , Howitz Michael , Olcén Per , Haglund Margaretha , van der Ende Arie , Pollard Andrew J
Published: February 2014

Objective

To investigate the relationship between the prevalence of smoking in the population and incidence of invasive meningococcal disease (IMD) among children under 5 years of age.

Design

Retrospective, longitudinal, observational study. Poisson regression controlled for confounding factors.

Setting

Norway, Sweden, Denmark and the Netherlands between 1975 and 2009.

Population

Total population of approximately 35 million people in these four countries.

Data sources

Data were collected from the Ministries of Health, National Statistics Bureaus and other relevant national institutes.

Results

In Norway, there was a significant positive relationship between the annual prevalence of daily smokers among individuals aged 25–49 years and the incidence of IMD in children under 5 years of age, unadjusted (RR=1.04–1.06, 95% CI 1.02 to 1.07, p<0.001) and after adjustment for time of year (quarter), incidence of influenza-like illness and household crowding (RR=1.05–1.07, 95% CI 1.03 to 1.09, p<0.001). Depending on age group, the risk of IMD increased by 5.2–6.9% per 1% increase in smoking prevalence among individuals aged 25–49 years in adjusted analyses. Using limited datasets from the three other countries, unadjusted analysis showed positive associations between IMD in children related to older smokers in Sweden and the Netherlands and negative associations related to younger smokers in Sweden. However, there were no demonstrable associations between incidence of IMD and prevalence of smoking, after adjustment for the same confounding variables.

Conclusions

The reduced incidence of IMD in Norway between 1975 and 2009 may partly be explained by the reduced prevalence of smoking during this period. High-quality surveillance data are required to confirm this in other countries. Strong efforts to reduce smoking in the whole population including targeted campaigns to reduce smoking among adults may have a role to play in the prevention of IMD in children.
IL-13Rα2-bearing, type II NKT cells reactive to sulfatide self-antigen populate the mucosa of ulcerative colitis
Authors: Fuss Ivan J , Joshi Bharat , Yang Zhiqiong , Degheidy Heba , Fichtner-Feigl Stefan , de Souza Heitor , Rieder Florian , Scaldaferri Franco , Schirbel Anja , Scarpa Melania , West Gail , Yi Chuli , Xu Lili , Leland Pamela , Yao Michael , Mannon Peter , Puri Raj K , Fiocchi Claudio , Strober Warren
Published: February 2014

Objective

Previous studies have shown that ulcerative colitis (UC) is associated with the presence of lamina propria non-invariant (Type II) NKT cells producing IL-13 and mediating epithelial cell cytotoxicity. Here we sought to define the antigen(s) stimulating the NKT cells and to quantitate these cells in the UC lamina propria.

Design

Detection of Type II NKT cells in UC lamina propria mononuclear cells (LPMC) with lyso-sulfatide loaded tetramer and quantum dot-based flow cytometry and staining. Culture of UC LPMCs with lyso-sulfatide glycolipid to determine sulfatide induction of epithelial cell cytotoxicity, IL-13 production and IL-13Rα2 expression. Blinded quantum dot-based phenotypic analysis to assess UC LPMC expression of IL-13Rα2, CD161 and IL-13.

Results

Approximately 36% of UC LPMC were lyso-sulfatide tetramer positive, whereas few, if any, control LPMCs were positive. When tested, the positive cells were also CD3 and IL-13Rα2 positive. Culture of UC LPMC with lyso-sulfatide glycolipid showed that sulfatide stimulates UC LPMC production of IL-13 and induces UC CD161 LPMC-mediated cytotoxicity of activated epithelial cells; additionally, lyso-sulfatide induces enhanced expression of IL-13Rα2. Finally, blinded phenotypic analysis of UC LP MC using multicolour quantum dot-staining technology showed that approximately 60% of the LPMC bear both IL-13Rα2 and CD161 and most of these cells also produce IL-13.

Conclusions

These studies show that UC lamina propria is replete with Type II NKT cells responsive to lyso-sulfatide glycolipid and bearing IL-13Rα2. Since lyso-sulfatide is a self-antigen, these data suggest that an autoimmune response is involved in UC pathogenesis.
Informing policy on open water drowning prevention: an observational survey of life jacket use in Washington state
Authors: Chung Celeste , Quan Linda , Bennett Elizabeth , Kernic Mary A , Ebel Beth E
Published: February 2014

Objective

To assess life jacket use among Washington State boaters and to examine the relationship between life jacket use and boating laws.

Methods

A statewide observational survey of boaters was conducted between August 2010 and September 2010. Data collection included age, sex, life jacket use, boat type, and weather and water conditions.

Results

Among 5157 boaters, 30.7% wore life jackets. Life jacket use was highest among groups required by state law: personal watercraft users (96.8%), people being towed (eg, water-skiers) (95.3%) and children 0–12 years old (81.7%). Children and youth were more likely to use a life jacket if any adult in the boat wore a life jacket: 100% versus 87.2% for 0–5 years, 92.8% versus 76.7% for 6–12 years and 81.4% versus 36.1% for 13–17 years. Adult role modelling was particularly beneficial for adolescents aged 13–17 years, who were not covered by a life jacket law. In multivariable analysis, the presence of at least one adult wearing a life jacket was associated with a 20-fold increased likelihood that adolescents were also wearing a life jacket.

Conclusions

Highest life jacket use was strongly associated with laws requiring use and with adult role modelling. Legislation requiring life jackets for ages 13–17 years and social marketing encouraging adult life jacket wear in the company of children and youth are promising strategies to increase life jacket use in Washington State.
The impact of dwell time variability on transit signal priority performance
Authors: Ghanim Mohammad S. , Dion Francois , Abu-Lebdeh Ghassan
Published: February 2014

Transit signal priority (TSP) is an operational control strategy that provides preferential treatments for transit vehicles at signalized intersections. Many transit agencies are currently considering the implementation of priority systems providing buses with preferential treatments at signalized intersections. While studies have demonstrated potential bus delay reductions, none has attempted to identify the problems posed by variable dwell times at bus stops. This study identifies the impacts of variable dwell times on the efficiency of transit signal priority systems. Results also show that, in general, variable dwell times negatively affect the TSP performance. However, and contrary to expectations, a number of scenarios with variable dwell times resulted in lower average bus delays than scenarios with fixed dwell times. These results are attributed to changes in progression and bus arrival patterns under variable dwell times resulting in an increasing number of buses arriving close enough to benefit from preferential treatments.
Fabrication and characterization of aluminum nitride pedestal-type optical waveguide
Authors: Alvarado M.A. , Pelegrini M.V. , Pereyra I. , Assumpção T.A.A. de , Kassab L.R.P. , Alayo M.I.
Published: February 2014

In this paper we present the fabrication and characterization of pedestal-type optical waveguides using aluminum nitride (AlN) as core layer. To the best knowledge of the authors, the utilization of AlN as core layer in pedestal-type waveguides has not been studied. The AlN thin films were obtained by radio frequency reactive magnetron sputtering from a pure aluminum target. The AlN refractive index was determined by ellipsometry. The optical waveguides were fabricated by the pedestal technique, which consists in etching the silicon oxide lower cladding layer before depositing the core layer. Thus, the waveguide geometrical definition is simplified because etching the AlN core is not necessary. AlN thin films of 0.6, 1, and 1.2 μm thick were deposited on thermally grown silicon dioxide using crystalline silicon (100) as substrate. The pedestal profile was defined using conventional photolithography, followed by plasma etching of the cladding layer. Optical propagation losses were measured for pedestal heights of 1 μm and widths from 1 to 100 μm.
LOX-1, oxidant stress, mtDNA damage, autophagy, and immune response in atherosclerosis
Authors: Ding Zufeng , Liu Shijie , Wang Xianwei , Dai Yao , Khaidakov Magomed , Romeo Francesco , Mehta Jawahar L.
Published: February 2014

As a major receptor for oxidized low density lipoprotein (ox-LDL), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is upregulated in many pathophysiological events, including endothelial cell dysfunction and smooth muscle cell growth, as well as monocyte migration and transformation into foam cells, which are present in atherosclerosis and myocardial ischemia. Excessive production of reactive oxygen species (ROS) increases LOX-1 expression, induces mitochondrial DNA damage, and activates autophagy. Damaged mitochondrial DNA that escapes from autophagy induces an inflammatory response. This paper reviews the potential link between LOX-1, mitochondrial DNA damage, autophagy, and immune response in atherosclerosis.
QUANTUM STRUCTURE OF FIELD THEORY AND STANDARD MODEL BASED ON INFINITY-FREE LOOP REGULARIZATION/RENORMALIZATION
Authors: WU YUE-LIANG
Published: February 2014

To understand better the quantum structure of field theory and standard model in particle physics, it is necessary to investigate carefully the divergence structure in quantum field theories (QFTs) and work out a consistent framework to avoid infinities. The divergence has got us into trouble since developing quantum electrodynamics in 1930s. Its treatment via the renormalization scheme is satisfied not by all physicists, like Dirac and Feynman who have made serious criticisms. The renormalization group analysis reveals that QFTs can in general be defined fundamentally with the meaningful energy scale that has some physical significance, which motivates us to develop a new symmetry-preserving and infinity-free regularization scheme called loop regularization (LORE). A simple regularization prescription in LORE is realized based on a manifest postulation that a loop divergence with a power counting dimension larger than or equal to the space–time dimension must vanish. The LORE method is achieved without modifying original theory and leads the divergent Feynman loop integrals well-defined to maintain the divergence structure and meanwhile preserve basic symmetries of original theory. The crucial point in LORE is the presence of two intrinsic energy scales which play the roles of ultraviolet cutoff Mcand infrared cutoff μsto avoid infinities. As Mccan be made finite when taking appropriately both the primary regulator mass and number to be infinity to recover the original integrals, the two energy scales Mcand μsin LORE become physically meaningful as the characteristic energy scale and sliding energy scale, respectively. The key concept in LORE is the introduction of irreducible loop integrals (ILIs) on which the regularization prescription acts, which leads to a set of gauge invariance consistency conditions between the regularized tensor-type and scalar-type ILIs. An interesting observation in LORE is that the evaluation of ILIs with ultraviolet-divergence-preserving (UVDP) parametrization naturally leads to Bjorken–Drell's analogy between Feynman diagrams and electric circuits, which enables us to treat systematically the divergences of Feynman diagrams and understand better the divergence structure of QFTs. The LORE method has been shown to be applicable to both underlying and effective QFTs. Its consistency and advantages have been demonstrated in a series of applications, which includes the Slavnov–Taylor–Ward–Takahaski identities of gauge theories and supersymmetric theories, quantum chiral anomaly, renormalization of scalar interaction and power-law running of scalar mass, quantum gravitational effects and asymptotic free power-law running of gauge couplings.
Electromagnetic fields in high energy heavy-ion collisions
Authors: Tuchin Kirill
Published: February 2014

I review properties of electromagnetic fields generated by colliding relativistic heavy ions and argue that they have a profound impact on the heavy-ion phenomenology. I discuss magnetic field effects on the quark gluon plasma flow, J/ψ dissociation, photon and dilepton production and quark energy loss.
Effects of beam energy distribution on fusion-evaporation excitation functions
Authors: Sagaidak Roman , Andreyev Andrei
Published: February 2014

A numerical approach has been developed for the calculation of fusion-evaporation excitation functions taking into account the heavy ion beam energy distribution inside the target. The approach uses statistical model approximations of the HIVAP code for the calculations of evaporation residue excitation functions in the ordinary way and the Monte Carlo TRIM simulations for the determination of beam energy distributions inside the target. Several applications of the approach have been considered to evaluate the effect of the beam energy distributions inside the target on fusion-evaporation excitation functions calculated in the ordinary way.
Isometric embeddings in bounded cohomology
Authors: Bucher M. , Burger M. , Frigerio R. , Iozzi A. , Pagliantini C. , Pozzetti M. B.
Published: February 2014

This paper is devoted to the construction of norm-preserving maps between bounded cohomology groups. For a graph of groups with amenable edge groups, we construct an isometric embedding of the direct sum of the bounded cohomology of the vertex groups in the bounded cohomology of the fundamental group of the graph of groups. With a similar technique we prove that if (X, Y) is a pair of CW-complexes and the fundamental group of each connected component of Y is amenable, the isomorphism between the relative bounded cohomology of (X, Y) and the bounded cohomology of X in degree at least 2 is isometric. As an application we provide easy and self-contained proofs of Gromov's Equivalence Theorem and of the additivity of the simplicial volume with respect to gluings along π1-injective boundary components with amenable fundamental group.
Dynamic load balancing in distributed virtual environments using heat diffusion
Authors: Deng Yunhua , Lau Rynson W. H.
Published: February 2014

Distributed virtual environments (DVEs) are attracting a lot of attention in recent years, due to the increasing popularity of online gaming and social networks. As the number of concurrent users of a DVE increases, a critical problem is on how the workload among multiple servers can be balanced in order to maintain real-time performance. Although a number of load balancing methods have been proposed, they either try to produce high quality load balancing results and become too slow or emphasize on efficiency and the load balancing results become less effective. In this article, we propose a new approach to address this problem based on heat diffusion. Our work has two main contributions. First, we propose a local and a global load balancing methods for DVEs based on heat diffusion. Second, we investigate two performance factors of the proposed methods, the convergence threshold and the load balancing interval. We have conducted a number of experiments to extensively evaluate the performance of the proposed methods. Our experimental results show that the proposed methods outperform existing methods in that our methods are effective in reducing server overloading while at the same time being efficient.
Scalable multimedia content analysis on parallel platforms using python
Authors: Gonina Ekaterina , Friedland Gerald , Battenberg Eric , Koanantakool Penporn , Driscoll Michael , Georganas Evangelos , Keutzer Kurt
Published: February 2014

In this new era dominated by consumer-produced media there is a high demand for web-scalable solutions to multimedia content analysis. A compelling approach to making applications scalable is to explicitly map their computation onto parallel platforms. However, developing efficient parallel implementations and fully utilizing the available resources remains a challenge due to the increased code complexity, limited portability and required low-level knowledge of the underlying hardware. In this article, we present PyCASP, a Python-based framework that automatically maps computation onto parallel platforms from Python application code to a variety of parallel platforms. PyCASP is designed using a systematic, pattern-oriented approach to offer a single software development environment for multimedia content analysis applications. Using PyCASP, applications can be prototyped in a couple hundred lines of Python code and automatically scale to modern parallel processors. Applications written with PyCASP are portable to a variety of parallel platforms and efficiently scale from a single desktop Graphics Processing Unit (GPU) to an entire cluster with a small change to application code. To illustrate our approach, we present three multimedia content analysis applications that use our framework: a state-of-the-art speaker diarization application, a content-based music recommendation system based on the Million Song Dataset, and a video event detection system for consumer-produced videos. We show that across this wide range of applications, our approach achieves the goal of automatic portability and scalability while at the same time allowing easy prototyping in a high-level language and efficient performance of low-level optimized code.
GDCSim
Authors: Gupta Sandeep K. S. , Banerjee Ayan , Abbasi Zahra , Varsamopoulos Georgios , Jonas Michael , Ferguson Joshua , Gilbert Rose Robin , Mukherjee Tridib
Published: February 2014

Energy-efficient data center design and management has been a challenge of increasing importance in the past decade due to its potential to save billions of dollars in energy costs. However, the state of the art in design and evaluation of data centers require designers to be expertly familiar with a prohibitively large number of domain-specific design tools that necessitate user intervention in each step of the design process. This is due to the lack of a holistic data center design tool. To fill this gap, this article presents an iterative green data center design framework, the Green Data Center Simulator (GDCSim), for the design and development of energy-efficient data centers.
Two-stage stochastic optimization for optimal power flow under renewable generation uncertainty
Authors: Phan Dzung , Ghosh Soumyadip
Published: February 2014

We propose a two-stage stochastic version of the classical economic dispatch problem with alternating-current power flow constraints, a nonconvex optimization formulation that is central to power transmission and distribution over an electricity grid. Certain generation decisions made in the first stage cannot further be changed in the second stage, where the uncertainty due to various factors such as renewable generation is realized. Any supply-demand mismatch in the second stage must be alleviated using high marginal cost power sources that can be tapped in short order. We solve a Sample-Average Approximation (SAA) of this formulation by capturing the uncertainty using a finite number of scenario samples. We propose two outer approximation algorithms to solve this nonconvex program to global optimality. We use recently discovered structural properties for the classical deterministic problem to show that when these properties hold the sequence of approximate solutions obtained under both alternatives has a limit point that is a globally optimal solution to the two-stage nonconvex SAA program. We also present an alternate local optimization approach to solving the SAA problem based on the Alternating Direction Method of Multipliers (ADMM). Numerical experiments for a variety of parameter settings were carried out to demonstrate the efficiency and usability of our method over ADMM for large practical instances.
Interview with Mark Guzdial, Georgia Institute of Technology
Authors: Denning Peter
Published: February 2014

Mark Guzdial is a Professor in the School of Interactive Computing at Georgia Institute of Technology (Georgia Tech). His research focuses on the intersection of computing and education, from the role of computing in facilitating education to how we educate about computing. In this interview with him, he discusses how we teach computing and to whom, especially his contention that a contextualized approach is a powerful tool to teach everyone about computing.
Book reviews
Authors: Kriebel Charles H.
Published: February 2014

It is a pleasure to have the opportunity to address this distinguished group of scholars from the Soviet Union and the United States of America. In the time available it is not possible for me to provide detailed comments on all of the important aspects of system design and development. To compensate in part for my restricted view I have included a bibliography that is representative of a broader perspective of the field and by subsequent reference should permit access to a wider universe of research.
Performance evaluation and management of information services
Authors: Lucas Henry C.
Published: February 2014

Performance evaluation techniques can contribute substantially to the successful management of the information services function. Three major purposes for performance evaluation in a typical commercially oriented computer installation are discussed including the acquisition of new hardware and software, the improvement of existing computer operations, and the improvement of the systems design process. The most suitable of the various techniques for performance evaluation are discussed for each major purpose. A proposal is also made for extending performance evaluation beyond the hardware and software system to encompass the user.
Operating systems principles and undergraduate computer science curricula
Authors: Denning Peter J.
Published: February 2014

In the years since 1969, the study of computer systems has assumed a role nearly equal in importance to "theory of computation" and "programming" in computer science curricula. In contrast, computer-systems was regarded as recently as 1965 as being inferior in importance to these two more traditional areas of study. This is a significant change in attitude. The harbingers of the change appear in ACM's Curriculum 68 [1], and the speed of its development is demonstrated in the report of Task Force VIII of the COSINE (Computer Sciences in Electrical Engineering) committee of the Commission on Education of the National Academy of Engineering, entitled "An Undergraduate Course on Operating Systems Principles" [2].
Comparison of alternatives for the representation of data items values in an information system
Authors: Maxwell William L. , Severance Dennis G.
Published: February 2014

This paper presents an analytic comparison of various techniques available for the representation of data within an information system. In selecting among alternatives, our design objective is to minimize the average space required by a data record. This will, in turn, minimize the average amount of data transported between secondary storage and main memory by the users of the information system and will tend to minimize the running time of the average retrieval program (Benner, 1967; Kennedy, 1973; and Severance, 1972).
A microprogrammed digital vocoder analyzer
Authors: Ancona Enrico I.
Published: February 2014

In order to demonstrate the feasibility of using small, general-purpose, microprogrammed computers for real-time digital signal processing, the application of the LX-1 microprocessor as a digital vocoder was investigated. The advantages of using a microprogrammed processor rather than special-purpose hardware for this application are the lower cost of such a general-purpose computer and the flexibility provided by the ability to change the microprogram.

The paper describes an implementation of the spectrum analyzer portion of the vocoder and its operation on the LX-1 simulator. The results show that real-time operation of the spectrum analyzer on the LX-1 prototype (with 70 nsec cycle time) could be expected with minimal additional hardware: a 200-sample input buffer and a fast multiplier.

Moreover, the proposed LSI version of LX-1 could be operated in half duplex mode for both analysis and synthesis, or to process several input channels.
Analysis of Infrared Signature Variation and Robust Filter-Based Supersonic Target Detection
Authors: Kim Sungho , Sun Sun-Gu , Kim Kyung-Tae
Published: February 2014

The difficulty of small infrared target detection originates from the variations of infrared signatures. This paper presents the fundamental physics of infrared target variations and reports the results of variation analysis of infrared images acquired using a long wave infrared camera over a 24-hour period for different types of backgrounds. The detection parameters, such as signal-to-clutter ratio were compared according to the recording time, temperature and humidity. Through variation analysis, robust target detection methodologies are derived by controlling thresholds and designing a temporal contrast filter to achieve high detection rate and low false alarm rate. Experimental results validate the robustness of the proposed scheme by applying it to the synthetic and real infrared sequences.
Design of Pulse Waveform for Waveform Division Multiple Access UWB Wireless Communication System
Authors: Yin Zhendong , Wang Zhirui , Liu Xiaohui , Wu Zhilu
Published: February 2014

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.
Geometric Lattice Structure of Covering and Its Application to Attribute Reduction through Matroids
Authors: Huang Aiping , Zhu William
Published: February 2014

The reduction of covering decision systems is an important problem in data mining, and covering-based rough sets serve as an efficient technique to process the problem. Geometric lattices have been widely used in many fields, especially greedy algorithm design which plays an important role in the reduction problems. Therefore, it is meaningful to combine coverings with geometric lattices to solve the optimization problems. In this paper, we obtain geometric lattices from coverings through matroids and then apply them to the issue of attribute reduction. First, a geometric lattice structure of a covering is constructed through transversal matroids. Then its atoms are studied and used to describe the lattice. Second, considering that all the closed sets of a finite matroid form a geometric lattice, we propose a dependence space through matroids and study the attribute reduction issues of the space, which realizes the application of geometric lattices to attribute reduction. Furthermore, a special type of information system is taken as an example to illustrate the application. In a word, this work points out an interesting view, namely, geometric lattice, to study the attribute reduction issues of information systems.
Effects of Chlorophyll-Derived Efflux Pump Inhibitor Pheophorbideaand Pyropheophorbideaon Growth and Macrolide Antibiotic Resistance of Indicator and Anaerobic Swine Manure Bacteria
Authors: Kraatz Mareike , Whitehead Terence R. , Cotta Michael A. , Berhow Mark A. , Rasmussen Mark A.
Published: February 2014

Natural plant compounds, such as the chlorophyll a catabolites pheophorbide a (php) and pyropheophorbide a (pyp), are potentially active in the gastrointestinal tracts and manure of livestock as antimicrobial resistance-modifying agents through inhibition of bacterial efflux pumps. To investigate whether php, a known efflux pump inhibitor, and pyp influence bacterial resistance, we determined their long-term effects on the MICs of erythromycin for reference strains of clinically relevant indicator bacteria with macrolide or multidrug resistance efflux pumps. Pyp reduced the final MIC endpoint forStaphylococcus (S.) aureusandEscherichia (E.) coliby up to 1536 and 1024 μg erythromycin mL−1or 1.4- and 1.2-fold, respectively. Estimation of growth parameters ofS. aureusrevealed that pyp exerted an intrinsic inhibitory effect under anaerobic conditions and was synergistically active, thereby potentiating the effect of erythromycin and partially reversing high-level erythromycin resistance. Anaerobe colony counts of total and erythromycin-resistant bacteria from stored swine manure samples tended to be lower in the presence of pyp. Tylosin, php, and pyp were not detectable by HPLC in the manure or medium. This is the first study showing that pyp affects growth and the level of sensitivity to erythromycin ofS. aureus,E. coli, and anaerobic manure bacteria.
Stability Calculation Method of Slope Reinforced by Prestressed Anchor in Process of Excavation
Authors: Li Zhong , Wei Jia , Yang Jun
Published: February 2014

This paper takes the effect of supporting structure and anchor on the slope stability of the excavation process into consideration; the stability calculation model is presented for the slope reinforced by prestressed anchor and grillage beam, and the dynamic search model of the critical slip surface also is put forward. The calculation model of the optimal stability solution of each anchor tension of the whole process is also given out, through which the real-time analysis and checking of slope stability in the process of excavation can be realized. The calculation examples indicate that the slope stability is changed with the dynamic change of the design parameters of anchor and grillage beam. So it is relatively more accurate and reasonable by using dynamic search model to determine the critical slip surface of the slope reinforced by prestressed anchor and grillage beam. Through the relationships of each anchor layout and the slope height of various stages of excavation, and the optimal stability solution of prestressed bolt tension design value in various excavation stages can be obtained. The arrangement of its prestressed anchor force reflects that the layout of the lower part of bolt and the calculation of slope reinforcement is in line with the actual. These indicate that the method is reasonable and practical.
Ocean Circulation and Water Mass Characteristics around the Galápagos Archipelago Simulated by a Multiscale Nested Ocean Circulation Model
Authors: Liu Yanyun , Xie Lian , Morrison John M. , Kamykowski Dan , Sweet William V.
Published: February 2014

Ocean circulation and water mass characteristics around the Galápagos Archipelago are studied using a four-level nested-domain ocean system (HYCOM). The model sensitivity to atmospheric forcing frequency and spatial resolution is examined. Results show, that with prescribed atmospheric forcing, HYCOM can generally simulate the major El Niño events especially the strong 1997-1998 events. Waters surrounding the archipelago show a large range of temperature and salinity in association with four different current systems. West zones of Isabella and Fernandina Islands are the largest upwelling zones, resulting from the collision of the Equatorial Undercurrent (EUC) with the islands, bringing relatively colder, salty waters to the surface and marking the location of the highest biological production. Model results, which agree well with observations, show a seasonal cycle in the transport of the EUC, reaching a maximum during the late spring/early summer and minimum in the late fall. The far northern region is characterized by warmer, fresher water with the greatest mixed layer depth as a result of Panama Current waters entering from the northeast. Water masses over the remainder of the region result from mixing of cool Peru Current waters and upwelled Cold Tongue waters entering from the east.
Acute Onset of Psychosis in a Patient with a Left Temporal Lobe Arachnoid Cyst
Authors: Mironov Alexander , John Sabu , Auerbach Jonathan , Jamaleddine Ghassan
Published: February 2014

Arachnoid cysts are considered a rare neurological tumor, few of which exhibit any symptomatology. A 38-year-old Haitian American female with no past psychiatric history presented with rapid onset of psychosis. Workup for medical etiology proved to be within normal limits, with the exception of a left temporal lobe arachnoid cyst. The purpose of this paper is to add to a number of existing case reports that suggest a relationship between such lesions and psychiatric illness.
Gradual Colonic Impaction of a Chicken Bone Associated with Inflammatory Pseudotumor Formation and Nonocclusive Colon Ischemia
Authors: Fosi Stefania , Altobelli Simone , Bindi Alessio , Villa Massimo , De Sanctis Flavio , Montuori Mauro , Ricciardi Edoardo , Rossi Piero , Petrella Giuseppe , Simonetti Giovanni
Published: February 2014

Foreign body (FB) ingestion is a common clinical problem and most FBs pass through the gastrointestinal tract without the need for intervention. A wide spectrum of clinical presentations may be possible and these can be either acute or chronic. We present a case of an 83-year-old woman featuring insidious abdominal discomfort who was hospitalized in our institution due to worsening symptoms. She underwent contrast-enhanced computed tomography (CT) evaluation which showed the presence of a significant parietal thickening of the transverse and descending colon, a mesenteric loose tissue imbibition, venous engorgement, and no filling defect of visceral arteries, suggesting a condition of nonocclusive colon ischemia. A hyperdense FB was identified in the sigma and was associated with a small pseudotumoral mass. The patient underwent surgical exploration which confirmed the hypoperfusional state of the colon, showing the presence of a chicken bone perforating the sigma and lying in the context of a pseudotumoral mass. Our experience shows how contrast-enhanced CT is feasible and can be strongly recommended as a first-line imaging tool on suspicion of colon ischemia and also how it can easily identify the underlying cause, in our case a FB sealed perforation of the sigma with pseudotumoral mass formation.
Lie Group Solution for Free Convective Flow of a Nanofluid Past a Chemically Reacting Horizontal Plate in a Porous Media
Authors: Rashidi M. M. , Momoniat E. , Ferdows M. , Basiriparsa A.
Published: February 2014

The optimal homotopy analysis method (OHAM) is employed to investigate the steady laminar incompressible free convective flow of a nanofluid past a chemically reacting upward facing horizontal plate in a porous medium taking into account heat generation/absorption and the thermal slip boundary condition. Using similarity transformations developed by Lie group analysis, the continuity, momentum, energy, and nanoparticle volume fraction equations are transformed into a set of coupled similarity equations. The OHAM solutions are obtained and verified by numerical results using a Runge‐Kutta‐Fehlberg fourth‐fifth order method. The effect of the emerging flow controlling parameters on the dimensionless velocity, temperature, and nanoparticle volume fraction have been presented graphically and discussed. Good agreement is found between analytical and numerical results of the present paper with published results. This close agreement supports our analysis and the accuracy of the numerical computations. This paper also includes a representative set of numerical results for reduced Nusselt and Sherwood numbers in a table for various values of the parameters. It is concluded that the reduced Nusselt number increases with the Lewis number and reaction parameter whist it decreases with the order of the chemical reaction, thermal slip, and generation parameters.
Augmented Lagrange Based on Modified Covariance Matching Criterion Method for DOA Estimation in Compressed Sensing
Authors: Si Weijian , Qu Xinggen , Liu Lutao
Published: February 2014

A novel direction of arrival (DOA) estimation method in compressed sensing (CS) is presented, in which DOA estimation is considered as the joint sparse recovery from multiple measurement vectors (MMV). The proposed method is obtained by minimizing the modified-based covariance matching criterion, which is acquired by adding penalties according to the regularization method. This minimization problem is shown to be a semidefinite program (SDP) and transformed into a constrained quadratic programming problem for reducing computational complexity which can be solved by the augmented Lagrange method. The proposed method can significantly improve the performance especially in the scenarios with low signal to noise ratio (SNR), small number of snapshots, and closely spaced correlated sources. In addition, the Cramér-Rao bound (CRB) of the proposed method is developed and the performance guarantee is given according to a version of the restricted isometry property (RIP). The effectiveness and satisfactory performance of the proposed method are illustrated by simulation results.