bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplification of Aminoglycoside Resistance Gene
aphA1
in Acinetobacter baumannii Results in Tobramycin Therapy Failure
Authors: McGann Patrick , Courvalin Patrice , Snesrud Erik , Clifford Robert J. , Yoon Eun-Jeong , Onmus-Leone Fatma , Ong Ana C. , Kwak Yoon I. , Grillot-Courvalin Catherine , Lesho Emil , Waterman Paige E.
Published: April 2014

Gene amplification is believed to play an important role in antibiotic resistance but has been rarely documented in clinical settings because of its unstable nature. We report a rise in MICs from 0.5 to 16 μg/ml in successive
Acinetobacter baumannii
isolated over 4 days from a patient being treated with tobramycin for an infection by multidrug-resistant
A. baumannii
, resulting in therapeutic failure. Isolates were characterized by whole-genome sequencing, real-time and reverse transcriptase PCR, and growth assays to determine the mechanism of tobramycin resistance and its fitness cost. Tobramycin resistance was associated with two amplification events of different chromosomal fragments containing the
aphA1
aminoglycoside resistance gene part of transposon Tn
6020
. The first amplification event involved low amplification (6 to 10 copies) of a large DNA fragment that was unstable and conferred tobramycin MICs of ≤8 μg/ml. The second event involved moderate (10 to 30 copies) or high (40 to 110 copies) amplification of Tn
6020
. High copy numbers were associated with tobramycin MICs of 16 μg/ml, impaired fitness, and genetic instability, whereas lower copy numbers resulted in tobramycin MICs of ≤8 μg/ml and no fitness cost and were stably maintained
in vitro
. Exposure
in vitro
to tobramycin of the initial susceptible isolate and of the
A. baumannii
AB0057 reference strain led to similar
aphA1
amplifications and elevated tobramycin MICs. To the best of our knowledge, this is the first report of
in vivo
development of antibiotic resistance secondary to gene amplifications resulting in therapy failure.

IMPORTANCE
A combination of whole-genome sequencing and mapping were used to detect an antibiotic resistance mechanism, gene amplification, which has been presumed for a long time to be of major importance but has rarely been reported in clinical settings because of its unstable nature. Two gene amplification events in a patient with an
Acinetobacter baumannii
infection treated with tobramycin were identified. One gene amplification event led to high levels of resistance and was rapidly reversible, while the second event led to low and more stable resistance since it incurred low fitness cost on the host. Gene amplification, with an associated rise in tobramycin MICs, could be readily reproduced
in vitro
from initially susceptible strains exposed to increasing concentrations of tobramycin, suggesting that gene amplification in
A. baumannii
may be a more common mechanism than currently believed. This report underscores the importance of rapid molecular techniques for surveillance of drug resistance.
Diverse Antibiotic Resistance Genes in Dairy Cow Manure
Authors: Wichmann Fabienne , Udikovic-Kolic Nikolina , Andrew Sheila , Handelsman Jo
Published: April 2014

Application of manure from antibiotic-treated animals to crops facilitates the dissemination of antibiotic resistance determinants into the environment. However, our knowledge of the identity, diversity, and patterns of distribution of these antibiotic resistance determinants remains limited. We used a new combination of methods to examine the resistome of dairy cow manure, a common soil amendment. Metagenomic libraries constructed with DNA extracted from manure were screened for resistance to beta-lactams, phenicols, aminoglycosides, and tetracyclines. Functional screening of fosmid and small-insert libraries identified 80 different antibiotic resistance genes whose deduced protein sequences were on average 50 to 60% identical to sequences deposited in GenBank. The resistance genes were frequently found in clusters and originated from a taxonomically diverse set of species, suggesting that some microorganisms in manure harbor multiple resistance genes. Furthermore, amid the great genetic diversity in manure, we discovered a novel clade of chloramphenicol acetyltransferases. Our study combined functional metagenomics with third-generation PacBio sequencing to significantly extend the roster of functional antibiotic resistance genes found in animal gut bacteria, providing a particularly broad resource for understanding the origins and dispersal of antibiotic resistance genes in agriculture and clinical settings.

IMPORTANCE
The increasing prevalence of antibiotic resistance among bacteria is one of the most intractable challenges in 21st-century public health. The origins of resistance are complex, and a better understanding of the impacts of antibiotics used on farms would produce a more robust platform for public policy. Microbiomes of farm animals are reservoirs of antibiotic resistance genes, which may affect distribution of antibiotic resistance genes in human pathogens. Previous studies have focused on antibiotic resistance genes in manures of animals subjected to intensive antibiotic use, such as pigs and chickens. Cow manure has received less attention, although it is commonly used in crop production. Here, we report the discovery of novel and diverse antibiotic resistance genes in the cow microbiome, demonstrating that it is a significant reservoir of antibiotic resistance genes. The genomic resource presented here lays the groundwork for understanding the dispersal of antibiotic resistance from the agroecosystem to other settings.
OverwhelmingCapnocytophaga canimorsusinfection in a patient with asplenia
Authors: Shahani Lokesh , Khardori Nancy
Published: April 2014

Patients with asplenia are prone to overwhelming infections due to encapsulated organisms. We report a 62-year-old man presenting with fever and weakness. His medical history was significant for splenectomy and owning a dog as pet. The patient on examination had evidence of animal bite and scratch marks on his lower extremity and developed dry gangrene of multiple digits of his upper extremity soon after admission. The patient's initial blood cultures were positive for Gram-negative rods, but no organism was identified.Capnocytophaga canimorsuswas the suspected organism and the patient's antibiotics were tailored accordingly, with good clinical recovery. The patient’ blood cultures finally grewC canimorsuson day 20 for which the patient had already been treated with prior clinical judgement. Physicians should be aware of this organism in the setting of sepsis in patients with asplenia and use appropriate antibiotics until further results are obtained.
‘Dancing eyes, dancing feet syndrome’ in small cell lung carcinoma
Authors: Sharma Chandramohan , Acharya Mihir , Kumawat Bansi Lal , Kochar Abhishek
Published: April 2014

A 60-year-old man presented with a 25-day history of acute onset instability of gait, tremulousness of limbs and involuntary eye movements. Examination revealed presence of opsoclonus, myoclonus and ataxia, without any loss of motor power in the limbs. Prompt investigations were directed towards identifying an underlying malignancy which is often associated with this type of clinical scenario. CT of the brain was normal and cerebrospinal fluid examination showed lymphocytic pleocytosis. A cavitatory lesion was found in the right lung base on the high-resolution CT of the chest and histopathological examination of this lung mass showed small cell lung carcinoma. The patient was managed symptomatically with levetiracetam and baclofen and referred to oncology department for resection of the lung mass.
Successful multidisciplinary treatment of hilar cholangiocarcinoma in a patient with complicated new-onset coronary artery disease
Authors: Fujikawa Takahisa , Tanaka Akira
Published: April 2014

We report a 69-year-old man suffering from hilar cholangiocarcinoma and concurrent new-onset complicated coronary artery disease. After implanting non-drug-eluting coronary stents, combination chemotherapy with gemcitabine and S-1 under continuation of dual antiplatelet therapy was carried out and partial tumour response was achieved. Subsequently, extended right hepatectomy with partial resection of the Spiegel lobe and left hepaticojejunostomy was performed while continuing preoperative single antiplatelet therapy with aspirin. The patient recovered well without any thromboembolic or bleeding complications. Like the current case, neoadjuvant chemotherapy and subsequent curative resection under continuation of antiplatelet therapy, followed by preceding coronary intervention, is one of the preferred options for the treatment of hepatobiliary malignancy in patients with concurrent new-onset coronary artery disease.
Acute appendicitis: a potential complication of video capsule endoscopy
Authors: Matta Abhishek , Koppala Jahnavi , Reddymasu Savio Charan , Lanspa Stephen
Published: April 2014

A 69-year-old man presented to our emergency room with malena and symptoms suggestive of anaemia. He was on chronic anticoagulation with warfarin for a mechanical aortic valve. He was haemodynamically stable. Laboratory investigations revealed a low haemoglobin level of 7.1 g/dL and a low-ferritin level of 6 ng/dL suggesting chronic gastrointestinal bleeding. Oesophagogastroduodenoscopy and colonoscopy were performed to identify the source of bleeding but were unfruitful. Video capsule endoscopy was performed. Fifteen hours after ingesting the capsule endoscope, the patient started having severe abdominal pain, nausea and vomiting. Abdominal X-ray did not show any bowel perforation. CT of the abdomen revealed impaction of the capsule endoscope at the appendiceal orifice and an inflamed appendix. The patient underwent laparoscopic appendectomy and made a good recovery.
Maltreatment or violence-related injury in children and adolescents admitted to the NHS: comparison of trends in England and Scotland between 2005 and 2011
Authors: Gonzalez-Izquierdo Arturo , Cortina-Borja Mario , Woodman Jenny , Mok Jacqueline , McGhee Janice , Taylor Julie , Parkin Chloe , Gilbert Ruth
Published: April 2014

Objective

Legislation to safeguard children from maltreatment by carers or violence by others was advanced in England and Scotland around 2004–2005 and resulted in different policies and services. We examined whether subsequent trends in injury admissions to hospital related to maltreatment or violence varied between the two countries.

Setting and participants

We analysed rates of all unplanned injury admission to National Health Service (NHS) hospitals in England and Scotland between 2005 and 2011 for children and adolescents aged less than 19 years.

Outcomes

We compared incidence trends for maltreatment or violence-related (MVR) injury and adjusted rate differences between 2005 and 2011 using Poisson or negative binomial regression models to adjust for seasonal effects and secular trends in non-MVR injury. Infants, children 1–10 years and adolescents 11–18 years were analysed separately.

Results

In 2005, MVR rates were similar in England and Scotland for infants and 1–10-year-olds, but almost twice as high in Scotland for 11–18-year-olds. MVR rates for infants increased by similar amounts in both countries, in line with rising non-MVR rates in England but contrary to declines in Scotland. Among 1–10-year-olds, MVR rates increased in England and declined in Scotland, in line with increasing non-MVR rates in England and declining rates in Scotland. Among 11–18-year-olds, MVR rates declined more steeply in Scotland than in England along with declines in non-MVR trends.

Conclusions

Diverging trends in England and Scotland may reflect true changes in the occurrence of MVR injury or differences in the way services recognise and respond to these children, record such injuries or a combination of these factors. Further linkage of data from surveys and services for child maltreatment and violence could help distinguish the impact of policies.
Clinical predictors of 2-year outcome of resective epilepsy surgery in adults with refractory epilepsy: a cohort study
Authors: Kanchanatawan B , Limothai C , Srikijvilaikul T , Maes M
Published: April 2014

Objectives

Resective epilepsy surgery is currently a standard treatment for intractable epilepsy. Seizure freedom and discontinuation of antiepileptic drugs are the ultimate goals of epilepsy treatment. This study was carried out to delineate (1) possible differences in the success rate of epilepsy surgery 6 and 24 months after surgery; and (2) the clinical predictors of a good response to surgery.

Setting

This is a cohort study performed at a tertiary care unit of a university hospital.

Participants

In this cohort study, 189 adults with intractable epilepsy who underwent epilepsy surgery were included. We collected clinical data at three time points, that is, preoperative and 6 and 24 months after surgery.

Primary and secondary outcome measures

Engel class I–IV classification was the primary outcome measure of epilepsy surgery. The authors statistically adjusted Engel class I–IV classification for postoperative changes in antiepileptic drugs and used this new classification as a secondary outcome variable.

Results

The success rate was 78.8% 6 months after surgery and increased to 88.3% 24 months after surgery. This success rate was reflected not only by the reduced number of seizures postsurgery, but also by a reduced dosage and use of antiepileptic drugs. Logistic regression analysis showed that a successful outcome of surgery is predicted by having temporal rather than extratemporal lobe epilepsy and less than nine presurgery seizures per month, while a positive familial history of epilepsy, younger age and dysphoric symptoms, the first 3 months after surgery, significantly worsened the outcome of surgery. Duration of illness, age at onset, epilepsy location, type of lesions and the presence of psychosis were not significant in predicting treatment outcome.

Conclusions

These findings have clinical relevance in that a better selection of patients based on the significant clinical predictors will increase the success rate of epilepsy surgery and treatment.
Improving electronic information sharing for palliative care patients
Authors: Pringle Amanda , Finucane Anne , Oxenham David
Published: April 2014

Coordination of services used by palliative care patients across care contexts is essential in providing patient centred care.

In Lothian, Edinburgh, a baseline audit in 2008 of patients known to all four specialist palliative care teams revealed only 49% had information available to out of hours (OOH) general practitioners (GPs).

This highlighted the poor handover and sharing of information, which are essential for providing quality care for palliative patients in accordance with their wishes, and for reducing inappropriate hospital admissions.

A number of quality improvement measures have been introduced, some nationally in Scotland, such as the roll out of Electronic Palliative Care Summaries (ePCS) – an electronic register containing up to date information including patient wishes and latest treatment decisions. In addition there have been changes to the GP Quality Outcomes Framework encouraging the use of electronic records. Locally, at Marie Curie Hospice, drivers were implemented including hosting GP education evenings promoting ePCS use, alteration of hospice discharge letter format to complement ePCS completion, in addition to offering specialist nurse support and presence at GP practice palliative care register meetings.

A re-audit in 2012 revealed that 75% of specialist palliative care patients had electronic information available to OOH services, and in 2013, 71% of patients. This represents a significant improvement in electronic information sharing across care contexts.

Building on the progress of ePCS, a new Electronic Key Information Summary is currently being rolled out across Scotland.

This quality improvement report reflects on the positive measures taken to address the important clinical need of effective electronic handover for specialist palliative care patients in Lothian. Furthermore, it highlights the ongoing requirement to continue to improve the quality and availability of electronically shared information for every patient known to palliative care services across care contexts.
Variable effects of 12 weeks of omega-3 supplementation on resting skeletal muscle metabolism
Authors: Gerling Christopher J. , Whitfield Jamie , Mukai Kazutaka , Spriet Lawrence L.
Published: April 2014

Omega-3 supplementation has been purported to improve the function of several organs in the body, including reports of increased resting metabolic rate (RMR) and reliance on fat oxidation. However, the potential for omega-3s to modulate human skeletal muscle metabolism has received little attention. This study examined the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on whole-body RMR and the content of proteins involved in fat metabolism in human skeletal muscle. Recreationally active males supplemented with 3.0 g/day of EPA and DHA (n = 21) or olive oil (n = 9) for 12 weeks. Resting muscle biopsies were sampled in a subset of 10 subjects before (pre) and after (post) omega-3 supplementation. RMR significantly increased (5.3%, p = 0.040) following omega-3 supplementation (Pre, 1.33 ±0.05; Post, 1.40 ±0.04 kcal/min) with variable individual responses. When normalizing for body mass, this effect was lost (5.2%, p = 0.058). Omega-3s did not affect whole-body fat oxidation, and olive oil did not alter any parameter assessed. Omega-3 supplementation did not affect whole muscle, sarcolemmal, or mitochondrial FAT/CD36, FABPpm, FATP1 or FATP4 contents or mitochondrial electron chain and PDH proteins, but did increase the long form of UCP3 by 11%. In conclusion, supplementation with a high dose of omega-3s for 12 weeks increased RMR in a small and variable manner in a group of healthy young men. Omega-3 supplementation also had no effect on several proteins involved in skeletal muscle fat metabolism and did not cause mitochondrial biogenesis.
Ecology of cultivable yeasts in pristine forests in northern Patagonia (Argentina) influenced by different environmental factors
Authors: Mestre María Cecilia , Fontenla Sonia , Rosa Carlos A.
Published: April 2014

Environmental factors influencing the occurrence and community structure of soil yeasts in forests are not well studied. There are few studies dedicated to Southern Hemisphere soil yeasts populations and even fewer focused on temperate forests influenced by volcanic activity. The present work aimed to study the ecology of soil yeast communities from pristine forests influenced by different environmental factors (precipitation, physicochemical properties of soil, tree species, soil region, and season). The survey was performed in 4 northern Patagonian forests: 2 dominated by Nothofagus pumilio and 2 by Nothofagus antarctica. Yeast communities were described with ecological indices and species accumulation curves, and their association with environmental characteristics was assessed using multivariate analysis. Each forest site showed a particular arrangement of species as a result of environmental characteristics, such as dominant plant species, nutrient availability, and climatic characteristics. Cryptococcus podzolicus was most frequently isolated in nutrient-rich soils, Trichosporon porosum dominated cold mountain forests with low nutrient and water availability in soil, and capsulated yeasts such as Cryptococcus phenolicus dominated forest sites with low precipitation. The present work suggests that environmental factors affecting yeast communities may not be the current soil characteristics but the result of complex interactions of factors including natural disturbances like volcanic activity.
Water resource developments in Ethiopia: potential benefits and negative impacts on the environment, vector-borne diseases, and food security
Authors: Yewhalaw D. , Hamels S. , Getachew Y. , Torgerson P.R. , Anagnostou M. , Legesse W. , Kloos H. , Duchateau L. , Speybroeck N.
Published: April 2014

To satisfy the growing demand for electricity, Ethiopia plans to increase its electricity production five-fold between 2010 and 2015, mainly through the construction of dams. A literature review shows that while dams can boost power and agricultural production, promote economic development, and facilitate flood control, they can also lead to environmental, ecological, and socioeconomic changes. Several case studies show that dams may alter the composition and density of vectors and intermediate host species, increase the incidence of malaria schistosomiasis and possibly lymphatic filariasis, and lead to eutrophication of reservoirs, soil erosion, and earthquakes. There is evidence that dams and commercial irrigation schemes can increase soil and water degradation, vulnerability to drought, and food insecurity in riverine and lacustrine areas downstream of dams. It appears that dams in Ethiopia are also vulnerable to high soil erosion rates and earthquakes. Consequently, the current and proposed large-scale dam construction program in Ethiopia requires in-depth research to improve our understanding of the unintended negative effects of projects and to guide the location, design, and implementation of appropriate preventive and remedial programs.
Properties analyses for the heterogeneous nonmotorized vehicle traffic based on cellular automaton model
Authors: Jiang Hang , Ren Gang , Zheng Liang , Chen Jingxu , Huang Zhengfeng
Published: April 2014

As traffic phenomena can be explained by physical method, this interdisciplinary domain has attracted many physicists to explore. The primary object of this research is to reveal the physical characteristics of heterogeneous nonmotorized vehicle traffic composing of conventional bicycles and electric bicycles. Cellular automaton (CA) model is an effective method to reveal the characteristics of the traffic, so a new CA model is proposed to simulate the flow characteristics, overtaking maneuvers patterns and segregation effect in the heterogeneous traffic. In order to realistically describe the traffic characteristics, the new model incorporates the honk effect, performance variance and erratic riding behavior of the nonmotorized vehicles. The simulations achieve three conclusions. First, increasing the ratio of electric bicycles can obtain higher flow and increase the number of overtaking maneuvers. Second, the honk can influence the density-flow diagram and stir up more overtaking maneuvers in the intermediate density region. Third, the existence of segregation effect which means conventional bicycles and electric bicycles could respectively gather together to form clusters is verified and elucidated in the heterogeneous traffic.
Periodic Orbits Associated with the Libration Points of the Massive Rotating Straight Segment
Authors: Romanov Volodymyr A. , Doedel Eusebius J.
Published: April 2014

The massive straight segment, rotating around the axis perpendicular to its center, is a simple alternative for more precise and sophisticated models that take into account the shape and mass density of natural asteroids. In this article, we give numerical results for the families of periodic orbits that emanate from the five libration points of massive straight segment, and for some secondary bifurcating families. Possible application and extension of the results to research on the motion of satellites near small irregular-shaped celestial bodies are also discussed. The numerical continuation and bifurcation algorithms we use in our study are based on boundary value techniques, as implemented in AUTO. An extensive set of python scripts for running AUTO will be made available at http://users.encs.concordia.ca/~doedel . These scripts can be used to recompute the results in this paper, and to do a wide selection of related calculations.
On Analytical Routes to Chaos in Nonlinear Systems
Authors: Luo Albert C. J.
Published: April 2014

In this paper, the analytical methods for approximate solutions of periodic motions to chaos in nonlinear dynamical systems are reviewed. Briefly discussed are the traditional analytical methods including the Lagrange stand form, perturbation methods, and method of averaging. A brief literature survey of approximate methods in application is completed, and the weakness of current existing approximate methods is also discussed. Based on the generalized harmonic balance, the analytical solutions of periodic motions in nonlinear dynamical systems with/without time-delay are reviewed, and the analytical solutions for period-m motion to quasi-periodic motion are discussed. The analytical bifurcation trees of period-1 motion to chaos are presented as an application.
Global Bifurcation Analysis of a Duffing–Van der Pol Oscillator with Parametric Excitation
Authors: Han Qun , Xu Wei , Yue Xiaole
Published: April 2014

In this paper, a composite cell state space is constructed by a multistage division of the continuous phase space. Based on point mapping method, global properties of dynamical systems can be analyzed more accurately and efficiently, and any small regions can be refined for clearly depicting some special basin boundaries in this cell state space. Global bifurcation of a Duffing–Van der Pol oscillator subjected to harmonic parametrical excitation is investigated. Attractors, basins of attraction, basin boundaries, saddles and invariant manifolds have been obtained. As the amplitude of excitation increases, it can be observed that the boundary crisis occurs twice. Then a basin boundary with Wada property appears in the state space and undergoes metamorphosis in the chaotic boundary crisis. At last, two attractors merge into a chaotic one when they simultaneously collide with the chaotic saddle embedded in the fractal boundary. All these results show the effectiveness of the proposed method in global analysis.
Location of Wire Faults Using Chaotic Signal Generated by an Improved Colpitts Oscillator
Authors: Xu Hang , Wang Bingjie , Li Jingxia , Wang Anbang , Wang Yuncai
Published: April 2014

We propose a method to locate wire faults using a chaotic signal generated by an improved Colpitts oscillator. The chaotic signal is divided into two parts: one serves as a reference signal, and the other serves as a probe signal which is sent down to the wire. The fault is detected by correlating the reference signal with the probe signal back-reflected from the fault. Experimental and numerical studies show that the chaotic signal generated by the improved Colpitts oscillator has a broad spectrum and excellent correlation properties. Using this chaotic signal, we experimentally prove our method can be used to locate open circuits, short circuits, impedance discontinuities and other different damage cases on wires, and also demonstrate its ability for testing live wires through the numerical simulation. The results show that a spatial resolution of 0.2 m and a maximum range of about 930 m can be achieved. Furthermore, the interference margin is about 167 dB for the digital signals such as Mil-Std 1553 data on wire.
Periodic perturbations of constrained motion problems on a class of implicitly defined manifolds
Authors: Calamai Alessandro , Spadini Marco
Published: April 2014

We study forced oscillations on differentiable manifolds which are globally defined as the zero set of appropriate smooth maps in some Euclidean spaces. Given a T-periodic perturbative forcing field, we consider the two different scenarios of a nontrivial unperturbed force field and of perturbation of the zero field. We provide simple, degree-theoretic conditions for the existence of branches of T-periodic solutions. We apply our construction to a class of second-order differential-algebraic equations.
A convenient procedure for the synthesis of fluoro-iron(III) complexes of common synthetic porphyrinates
Authors: Meininger Daniel J. , Muzquiz Nicanor , Arman Hadi D. , Tonzetich Zachary J.
Published: April 2014

We report here an improved method for the preparation of fluoro-iron(III) porphyrinate complexes. Treatment of [ Fe 2( P )2(μ- O )] (P = tetraphenylporphyrinate {TPP}, tetra-p-tolylporphyrinate {TTP}, or octaethylporphyrinate {OEP}) or [ Fe ( OH )( OH 2)( TMP )] (TMP = tetramesitylporphyrinate) with the commercially available fluorinating agent, Et 3 N ·3 HF , in dichloromethane affords the desired [ FeF ( P )] complexes in a straightforward fashion and in good yield while avoiding the use of aqueous hydrofluoric acid. All fluoro-iron(III) complexes have been completely characterized by a series of different spectroscopic techniques including cyclic voltammetry. Reaction of a representative complex, [ FeF ( OEP )], with various chloride reagents demonstrates that halide exchange with chloride is facile, but only proceeds at an appreciable rate in the presence of proton sources. Unexpectedly, treatment of [ FeF ( OEP )] with NOBF 4 did not to lead formation of an oxidized species, but rather to formation of the { Fe – NO }6 complex, [ Fe ( NO )( OEP )]( BF 4).
STRATEGIC INNOVATION AT THE FIRM LEVEL: THE IMPACT OF STRATEGIC MANAGEMENT PRACTICES ON ENTREPRENEURIAL ORIENTATION
Authors: MURIMBIKA McEDWARD , URBAN BORIS
Published: April 2014

The study combines the research domains of strategic management and corporate innovation by examining the impact of strategic management practices on entrepreneurial orientation (EO). Recognising the importance of internal business processes that enable firm entrepreneurial behaviour, it is hypothesised that higher levels of EO are positively associated with the strategic management practices of (1) locus of planning, (2) scanning intensity, (3) planning flexibility, (4) planning horizon, and (5) strategy and financial control attributes. Empirical testing takes place in an under-researched emerging market context on a sample of 219 financial and business services firms. The results provide support for the positive impact that the different strategic management practices have on EO. A practical consideration is for managers to leverage the strategic management practices so that the firm's position on the conservative-entrepreneurial continuum is increased by its propensity to be innovative, proactive, and be willing to take risks when confronted by uncertainty.
Bifurcation analysis in a stage-structured predator–prey model with maturation delay
Authors: Liu Jia
Published: April 2014

In this paper, we investigate the impact of maturation delay on the positive equilibrium solutions in a stage-structured predator–prey system. By analyzing the characteristic equation we derive the conditions for the emergence of Hopf bifurcation. By applying the normal form and the center manifold argument, the direction as well as the stability of periodic solutions bifurcating from Hopf bifurcation is explored. Results show that maturation delay can change the nature of the positive equilibrium solutions, and the loss of equilibrium stability occurs as a consequence of Hopf bifurcation. When Hopf bifurcation takes place, periodic solution arises and is further demonstrated to be asymptotically stable. In addition, the periodic solutions appear only for intermediate maturation delay, that is, there exists a delay window, outside of which the positive equilibrium is locally stable. Furthermore, numerical analysis shows that Hopf bifurcation is favored by a superior competition for adult predators to juveniles, a smaller mortality on juvenile and/or adult predators, and a higher resource carrying capacity. Interestingly, increasing food carrying capacity can lead to the emergence of irregular chaotic dynamics and regular limit cycles.
The effect of moisture and relative proportions of clay minerals (smectite, chlorite and illite) on the performance of unbound granular base course (UGM)
Authors: Hussain Jawad , Wilson Douglas J. , Black Philippa M.
Published: April 2014

An increase in moisture accelerates the deterioration of a pavement and this is especially so for unbound granular materials below the pavement surface. One of the possible reasons for this accelerated deterioration can be the mineralogical makeup of the aggregates, which can include clays. This research paper discusses the effect of the relative proportions of clay minerals on the performance of different base course materials in repeated load triaxial (RLT) tests considering moisture variation. The materials selected for this study were sourced from greywacke sedimentary rocks from both the North and South Islands of New Zealand. The mineralogical makeup of the clay content present in the base course materials was determined by X-ray powder diffraction (XRD). The performance of these materials was further tested in RLT tests at different moisture and drainage conditions. The results of the XRD and RLT tests showed that aggregates with high relative proportions of smectite clay minerals can decrease the load-bearing capacity of the base course material when moisture is introduced into the pavement materials.
Feet on the ground: engineering geology past, present and future
Authors: Griffiths James S.
Published: April 2014

Engineering geology has a long and rich heritage and the UK has been in the vanguard of the development of the subject as a distinct discipline, with the first book on the subject being published in London in 1880. Since then, engineering geology has been applied to projects around the world and engineering geologists have become core members of planning, investigation, design and construction teams in the civil engineering and mining industries. However, in the past few decades we have seen numerical analyses increasingly being accepted as the answer to all geotechnical design questions, although as engineering geologists we are used to dealing with natural materials and processes and recognize that their inherent variability cannot always be reduced to a simple numerical value. Consequently, how do we ensure that any proposed construction works in civil engineering or mining take full account of this variability and the uncertainties that result? To enable engineering geologists to understand and describe these uncertainties are there fundamental skills that define an engineering geologist and, if so, how can these skills be taught or acquired? Also, in a world dominated by readily accessible data that can be downloaded and analysed for so many planned development sites, how important are the field techniques of observation and mapping that an older generation of engineering geologists, including the author, considered their defining skill? Concentrating on the role of engineering geology in relation to civil engineering, these are amongst the questions explored in this paper, leading to observations as to how the profession might develop in the future in order to meet the needs of society.
Why give away something for nothing? Investigating virtual goods pricing and permission strategies
Authors: Ba Sulin , Ke Dan , Stallaert Jan , Zhang Zhongju
Published: April 2014

With the rapid increase of virtual goods created for virtual world exchanges and the record growth of user-to-user transactions in these in-world economies, an important question is how a creator sets prices for a virtual good so as to maximize her profit from her creation. Virtual goods share similar economic properties (such as substantial production cost and negligible marginal cost) with other types of digital goods. However, one aspect that distinguishes a virtual good is that consumers in a virtual world may want to use multiple copies of the identical good
at the same time
, and such simultaneous use of multiple copies of the identical good
increases a consumer's utility
. In this research, we focus on the COPY permission of virtual goods. We develop an economic model to examine under what conditions the COPY permission setting leads to the highest profit for the creator of a virtual good, and what the pricing strategies are in a dynamic setting when such permission choices are present. Theoretical and practical implications of the research are discussed.
The sustainability of corporate wikis
Authors: Arazy Ofer , Croitoru Arie
Published: April 2014

While existing theoretical frameworks describe collective technology adoption patterns, they provide little insight regarding the expected patterns of wiki activity within projects. Another impediment to the study of wiki sustainability is the absence of time-series analysis methods that are suitable for the unique patterns of wiki activity logs. The primary goals of this study are to: (i) develop a novel method for analyzing wiki edit activity logs, (ii) reveal the temporal patterns of corporate wiki edit activity, and (iii) study the factors impacting wikis' sustainability. A validation of our proposed method demonstrates that it is superior to the baseline algorithm in the face of noisy data. Our empirical study combines wiki system edit activity logs with a survey of users' perceptions, and explores 33277 distinct wiki applications within one global organization over the first 5 years of wiki operation. Our results reveal six different prototypical wiki activity patterns, and show that most corporate wikis become inactive after a relatively short period. Findings from the user survey show that users of sustainable wikis are more satisfied with the wiki system and its contents, and feel that the wiki provides them with a sense of community and productivity enhancements.
Uncovering and testing archetypes of effective public sector CIOs
Authors: Dawson Gregory S. , Watson Richard T.
Published: April 2014

Given the importance of public sector CIOs to government performance and citizens' faith in democracy as an efficient provider of services, it is important to understand what makes some government CIOs more effective than others. Q Method is used to uncover five archetypes of public sector CIOs which are shown to be reliable across two Q sorts. These archetypes include politically-oriented CIO, savvy negotiator, technology optimizer, and skillful communicator. Further analysis using a tournament scoring approach indicates that business-oriented CIOs are the most effective. Applying a stakeholder perspective to interpret the results, it is proposed that business-oriented CIOs understand the value in tracking closely to an organization's business leaders and strategically ignoring other stakeholders in their environment, even politically powerful ones. The development and comparison of archetypes provide a new focus of CIO research by extending from the individual level of the attribute to a combination of attributes (archetypes).
Analyzing information systems researchers' productivity and impacts
Authors: Hu Paul Jen-Hwa , Chen Hsinchun
Published: April 2014

Quantitative assessments of researchers' productivity and impacts are crucial for the information systems (IS) discipline. Motivated by its growing popularity and expanding use, we offer a perspective on the h index, which refers to the number of papers a researcher has coauthored with at least h citations each. We studied a partial list of 232 top IS researchers who received doctoral degrees between 1957 and 2003 and chose Google Scholar as the source for our analyses. At the individual level, we attempted to identify some of the most productive, high-impact researchers, as well as those who exhibited impressive paces of productivity. At the institution level, we revealed some institutions with relatively more productive researchers, as well as institutions that had produced more productive researchers. We also analyzed the overall IS community by examining the primary research areas of productive scholars identified by our analyses. We then compared their h index scores with those of top scholars in several related disciplines
Explaining U.S. consumer behavior with news sentiment
Authors: Uhl Matthias W.
Published: April 2014

We introduce a novel dataset with a news sentiment index that was constructed from a selection of over 300,000 newspaper articles from five of the top ten U.S. newspapers by circulation. By constructing ARMA models, we show that news and consumer sentiment, when combined with other macroeconomic variables, achieve statistically significant results to explain changes in private consumption. We make three distinct findings with respect to sentiment in consumption behavior models: first, both consumer and news sentiment add explanatory power and statistical significance to conventional consumer behavior models. Second, consumer sentiment, measured by the University of Michigan Index of Consumer Sentiment, adds more explanatory power and statistical significance than news sentiment when tested individually. Third, news sentiment is able to determine the signs of all coefficients in the model correctly, whereas consumer sentiment does not. In general, we conclude that news sentiment is a useful variable to add in consumer behavior models, especially when coupled with consumer sentiment and other macroeconomic variables. Tested individually, news sentiment is as good a proxy as personal income for explaining private consumption growth when tested individually.
Cloud-based malware detection for evolving data streams
Authors: Masud Mohammad M. , Al-Khateeb Tahseen M. , Hamlen Kevin W. , Gao Jing , Khan Latifur , Han Jiawei , Thuraisingham Bhavani
Published: April 2014

Data stream classification for intrusion detection poses at least three major challenges. First, these data streams are typically infinite-length, making traditional multipass learning algorithms inapplicable. Second, they exhibit significant concept-drift as attackers react and adapt to defenses. Third, for data streams that do not have any fixed feature set, such as text streams, an additional feature extraction and selection task must be performed. If the number of candidate features is too large, then traditional feature extraction techniques fail.

In order to address the first two challenges, this article proposes a multipartition, multichunk ensemble classifier in which a collection of
v
classifiers is trained from
r
consecutive data chunks using
v
-fold partitioning of the data, yielding an ensemble of such classifiers. This multipartition, multichunk ensemble technique significantly reduces classification error compared to existing single-partition, single-chunk ensemble approaches, wherein a single data chunk is used to train each classifier. To address the third challenge, a feature extraction and selection technique is proposed for data streams that do not have any fixed feature set. The technique's scalability is demonstrated through an implementation for the Hadoop MapReduce cloud computing architecture. Both theoretical and empirical evidence demonstrate its effectiveness over other state-of-the-art stream classification techniques on synthetic data, real botnet traffic, and malicious executables.
Toward a broader vision for Information Systems
Authors: Nunamaker, Jr. Jay F. , Briggs Robert O.
Published: April 2014

In December of 2009, several founders of the Information Systems (IS) academic discipline gathered for a panel discussion at the International Conference on Information Systems to present their visions for the future of the field, and their comments were summarized in the inaugural issue of TMIS [Davis et al., 2010; J. F. J. Nunamaker et al., 1991]. To assure a robust future, they argued, IS journals, conferences, reviewers, promotion committees, teachers, researchers, and curriculum developers must broaden the scope of IS. This article explores the need for a broader vision to drive future development of the IS discipline.
From information to operations
Authors: Padmanabhan Balaji , Hevner Alan , Cuenco Michael , Shi Crystal
Published: April 2014

In business, information is abundant. Yet, effective use of that information to inform and drive business operations is a challenge. Our industry-university collaborative project draws from a rich dataset of commercial demographics, transaction history, product features, and Service Quality Index (SQI) factors on shipping transactions at FedEx. We apply inductive methods to understand and predict customer churn in a noncontractual setting. Results identify several SQI variables as important determinants of churn across a variety of analytic approaches. Building on this we propose the design of a Business Intelligence (BI) dashboard as an innovative approach for increasing customer retention by identifying potential churners based on combinations of predictor variables such as demographics and SQI factors. This empirical study contributes to BI research and practice by demonstrating the application of data analytics to the fundamental business operations problem of customer churn.
Decision support for containing pandemic propagation
Authors: Arora Hina , Raghu T. S. , Vinze Ajay
Published: April 2014

This research addresses complexities inherent in dynamic decision making settings represented by global disasters such as influenza pandemics. By coupling a theoretically grounded Equation-Based Modeling (EBM) approach with more practically nuanced Agent-Based Modeling (ABM) approach we address the inherent heterogeneity of the “influenza pandemic” decision space more effectively. In addition to modeling contributions, results and findings of this study have three important policy implications for pandemic containment; first, an effective way of checking the progression of a pandemic is a multipronged approach that includes a combination of pharmaceutical and non-pharmaceutical interventions. Second, mutual aid is effective only when regions that have been affected by the pandemic are sufficiently isolated from other regions through non-pharmaceutical interventions. When regions are not sufficiently isolated, mutual aid can in fact be detrimental. Finally, intraregion non-pharmaceutical interventions such as school closures are more effective than interregion nonpharmaceutical interventions such as border closures.
Live-chat agent assignments to heterogeneous e-customers under imperfect classification
Authors: Goes Paulo , Ilk Noyan , Yue Wei T. , Zhao J. Leon
Published: April 2014

Many e-commerce firms provide live-chat capability on their Web sites to promote product sales and to offer customer support. With increasing traffic on e-commerce Web sites, providing such live-chat services requires a good allocation of service resources to serve the customers. When resources are limited, firms may consider employing priority-processing and reserving resources for high-value customers. In this article, we model a reserve-based priority-processing policy for e-commerce systems that have imperfect customer classification. Two policy decisions considered in the model are: (1) the number of agents exclusively reserved for high-value customers, and (2) the configuration of the classification system. We derive explicit expressions for average waiting times of high-value and low-value customer classes and define a total waiting cost function. Through numerical analysis, we study the impact of these two policy decisions on average waiting times and total waiting costs. Our analysis finds that reserving agents for high-value customers may have negative consequences for such customers under imperfect classification. Further, we study the interaction between the two policy decisions and discuss how one decision should be modified with respect to a change in the other one in order to keep the waiting costs minimized.