bluuebunny/crossref_metadata_2025 huggingface dataset:
A new ventilatory threshold equation for aerobically trained men and women
Authors: Malek Moh H. , Coburn Jared W.
Published: January 2009

The purposes of the present study were to (i) modify previously published ventilatory threshold (VT) equations using the constant error (CE) values for aerobically trained individuals from a recent study; (ii) cross‐validate the modified equations to determine their accuracy for estimating VT in aerobically trained individuals; (iii) derive a new non‐exercise based equation for estimating VT in aerobically trained individuals if the modified equations are found to be inaccurate; and (iv) cross‐validate the new VT equation using the Predicted REsidual Sum of Squares (PRESS) statistic and an independent sample of aerobically trained individuals. Two hundred and eight (n = 208) aerobically trained men and women (mean ± SD: age = 38·8 ± 10·4 year) performed a maximal incremental test on a cycle ergometer to determine the observed VT. The predicted VT values from seven published equations were compared with the observed VT by examining the CE, standard error of estimate, validity coefficient (r), and total error (TE). Cross‐validation of the modified equations resulted in high %TE values. Therefore, a new VT equation was derived. Cross‐validation of this equation on an independent sample of 72 subjects resulted in a low %TE value. The new model is recommended over previous models for estimating VT in aerobically trained individuals.
Determination of the mitral papillary muscle positions by the septal‐to‐free wall arc ratio method
Authors: Hakacova Nina , Robinson Anna M. C. , Maynard Charles , Wagner Galen S. , Idriss Salim F.
Published: January 2009

Background:  Determination of mitral papillary muscle positions is of increasing interest in wide spectrum of clinical cardiology fields. Particularly, relative positioning of the papillary muscles between the inter‐ventricular septum and the left ventricular free wall is of interest. A reproducible method for determination of papillary muscle positions has not been established. In this study a new ‘septal‐to‐free wall arc ratio’ (SFAR) method for measuring papillary muscle positions is presented. The reproducibility of the SFAR method between echocardiographic (ECHO) and magnetic resonance (MRI) modalities and between observers is tested.

Methods:  Twenty subjects with structurally normal hearts in whom both MRI and ECHO were performed in 2007 were included in the study. Papillary muscle positions were determined using the SFAR method. Inter‐modality (ECHO and MRI) and inter‐observer reproducibility of the methods was assessed by calculating correlation coefficients and the mean difference from agreement.

Results:  The inter‐modality correlation of the SFAR method was 0·80 (P < 0·0001) for both papillary muscles. The mean difference of measurements from agreement was 4% for the superior and 2% for the inferior papillary muscle. The inter‐observer correlation was 0·93 (P < 0·0001) for superior and 0·90 (P = 0·0002) for inferior papillary muscle. The mean inter‐observer difference from agreement was 2% for superior and 3% for inferior papillary muscle.

Conclusions:  The SFAR method may be applied in wide range of both scientific and clinical medical fields as a reproducible method for determination of papillary muscle positions with the benefit of estimation of relative papillary muscle positions both from the septum and the free wall.
A Finite‐Element Approach to Predict Permanent Deformation Behaviour of Hot Mix Asphalt Based on Fundamental Material Tests and Advanced Rheological Models
Authors: Blab R. , Kappl K. , Aigner E. , Lackner R.
Published: January 2009

Abstract:  An ongoing research project, undertaken at the Christian Doppler Laboratory for ‘performance‐based optimisation of flexible road pavements’, focuses on the evaluation of advanced rheological models (i.e. Power Law, Huet and Huet–Sayegh) to describe permanent deformation behaviour of hot mix asphalt (HMA) and their implementation in a finite‐element (FE) code. To accomplish this, an appropriate algorithm was developed for the summation of the different contributions of the stress history to determine the resulting creep strain tensor to simulate real‐life stress/strain situations in flexible road pavements. Furthermore, the mathematical background for parameter identification from dynamic stiffness tests (four‐point bending beam and dynamic tension compression tests) has been developed and a straightforward programme for data fitting is presented. For the validation of the implemented constitutive equations derived for the selected rheological models, a FE simulation of triaxial tests on cylindrical HMA specimens was carried out.
Effect of Evidence‐Based Acute Pain Management Practices on Inpatient Costs
Authors: Brooks John M. , Titler Marita G. , Ardery Gail , Herr Keela
Published: January 2009

Objectives. To estimate hospital cost changes associated with a behavioral intervention designed to increase the use of evidence‐based acute pain management practices in an inpatient setting and to estimate the direct effect that changes in evidence‐based acute pain management practices have on inpatient cost.

Data Sources/Study Setting. Data from a randomized “translating research into practice” (TRIP) behavioral intervention designed to increase the use of evidence‐based acute pain management practices for patients hospitalized with hip fractures.

Study Design. Experimental design and observational “as‐treated” and instrumental variable (IV) methods.

Data Collection/Extraction Methods. Abstraction from medical records and Uniform Billing 1992 (UB92) discharge abstracts.

Principal Findings. The TRIP intervention cost on average $17,714 to implement within a hospital but led to cost savings per inpatient stay of more than $1,500. The intervention increased the cost of nursing services, special operating rooms, and therapy services per inpatient stay, but these costs were more than offset by cost reductions within other cost categories. “As‐treated” estimates of the effect of changes in evidence‐based acute pain management practices on inpatient cost appear significantly underestimated, whereas IV estimates are statistically significant and are distinct from, but consistent with, estimates associated with the intervention.

Conclusions. A hospital treating more that 12 patients with acute hip fractures can expect to lower overall cost by implementing the TRIP intervention. We also demonstrated the advantages of using IV methods over “as‐treated” methods to assess the direct effect of practice changes on cost.
The Impact of Music on Childhood and Adolescent Achievement*
Authors: Southgate Darby E. , Roscigno Vincent J.
Published: January 2009

Objective. The study examines the association between music involvement and academic achievement in both childhood and adolescence using three measures of music participation: in school, outside of school, and parental involvement in the form of concert attendance.

Methods. We review prior work pertaining to music's impact on achievement and then draw from two nationally representative data sources (ECLS‐K and NELS:88). Our analyses apply logistic and OLS regression techniques to assess patterns of music involvement and possible effects on math and reading performance for both elementary and high school students.

Results. Music involvement varies quite systematically by class, and gender status, and such involvement holds implications for both math and reading achievement, and for young children and adolescents. Notably, associations with achievement persist in our modeling even when prior achievement levels are accounted for. Although music does mediate some student background effects, this mediation is only minimal.

Conclusions. Music participation, both inside and outside of school, is associated with measures of academic achievement among children and adolescents. Future work should further delineate the relevant processes of music involvement, as well as how background inequalities and music involvement intersect in relation to educational performance.
Motivating Participation: The Symbolic Effects of Latino Representation on Parent School Involvement*
Authors: Shah Paru
Published: January 2009

Objective. Decades of research suggest that parental involvement is vital for positive student academic achievement and thus one often‐proposed solution to alleviate the poor educational outcomes of minority students is to increase their parents' participation in school. Building on a psychological motivation argument, I investigate how the symbolic effects of minority representation impact minority parent involvement.

Method. I test my hypotheses with original survey data from 324 Latino parents in Chicago.

Results. My analysis suggests that, as hypothesized in the symbolic representation literature, Latinos in positions of power within schools send important heuristic cues to Latino parents that change their orientations to participation and ultimately manifest as increased school involvement.

Conclusions. These results support education policies that attempt to increase the minority presence in schools at the administrative and governance levels, and highlight the need for greater enforcement of current diversity requirements under NCLB.
Distinctions Between Worry and Perceived Risk in the Context of the Theory of Planned Behavior
Authors: Schmiege Sarah J. , Bryan Angela , Klein William M. P.
Published: January 2009

Worry and risk perception were integrated into the theory of planned behavior (TPB) within health and non‐health domains (flossing and academic coursework, respectively). Models were estimated and replicated in 2 undergraduate samples (ns = 191 and 309), with effects of worry and risk on intentions expected to occur primarily through attitudes. Past behavior was modeled through effects on all TPB constructs and through interactions with worry and risk. Worry positively predicted intentions and attitudes (and norms in the non‐health domain) for those at the lowest levels of prior behavior. Risk perceptions negatively predicted intentions and self‐efficacy (and attitudes in the health context) also for those at low levels of prior behavior. Implications for further theory development are discussed.
Trust and Influence in Combat: An Interdependence Model
Authors: Sweeney Patrick J. , Thompson Vaida , Blanton Hart
Published: January 2009

Two studies tested an interdependence model of trust development and the links between trust and influence in the in extremis environment of combat, and a non‐combat replication. Structural equation modeling was used to test the model. Results from both studies suggested that a modified interdependence model provided a plausible explanation for how leaders may earn subordinate trust, through fostering the establishment of cooperative interdependence and being perceived as credible. Credibility was demonstrated through both competence and good character, and organizational structures that were in place contributed to trust by encouraging leaders to behave cooperatively toward group members. Most importantly, the level of trust subordinates had in their leaders determined the amount of leader influence subordinates accepted.
Preinvestment Negotiation Characteristics and Dismissal in Venture Capital‐Backed Firms
Authors: Erikson Truls , Berg‐Utby Terje
Published: January 2009

In this study, we investigated idiosyncratic preinvestment process characteristics that influence the dismissal of management team members of venture capital‐backed firms in the postinvestment phase by analyzing sixty‐three portfolio firms. We considered two salient perspectives within the literature on governance of interfirm relationships: contractual and relational governance, which are related to positional and collaborative negotiation styles. Our findings indicate that positional bargaining in the preinvestment phase may be a reliable indicator that there is a greater risk that new venture team members will be dismissed when things get tough in the post‐investment period.
Irrigation production functions with water‐capital substitution
Authors: Shani Uri , Tsur Yacov , Zemel Amos , Zilberman David
Published: January 2009

The dynamics of biomass growth implies that the yield of irrigated crops depends, in addition to the total amount of water applied, on irrigation scheduling during the growing period. Advanced irrigation technologies relax constraints on irrigation rates and timing, allowing us to better adjust irrigation scheduling to the varying needs of the plants along the growing period. Irrigation production functions, then, should include capital (or expenditures on irrigation equipment) in addition to aggregate water. We derive such functions and study their water‐capital substitution properties. Implications for water demand and adoption of irrigation technologies are investigated. A numerical example illustrates these properties.
Agricultural technology and child labor: evidence from India
Authors: Self Sharmistha , Grabowski Richard
Published: January 2009

Child labor continues to be a major problem in developing countries, particularly in agricultural countries. The latest ILO global report points out that nine out of every ten child laborers is involved in the agricultural sector. The focus of this article is on the rural sector in India, a country where child labor continues to be prevalent. A number of factors have been found to significantly influence the extent of child labor. This article will focus on the type of technology utilized in the agricultural sector. Technology is divided into two types: biochemical and mechanical. The empirical results indicate that biochemical technology has both positive and negative effects on child labor. However, mechanical technology is found to have a statistically significant and negative impact on child labor.
Resistance of the brown alga Fucus vesiculosus to herbivory
Authors: Jormalainen Veijo , Ramsay Tuija
Published: January 2009

Herbivory is typically intense in marine littoral environments; thus, macrophytes are expected to evolve defenses against grazing. Although putative defenses of macrophytes are widely studied, there is lack of studies demonstrating the main premises of defense adaptations: the consequences of herbivory to macrophytes, genetic variation of defense traits and the costs and benefits of defenses in natural environment. We conducted a factorial experiment, where we manipulated amount of herbivory, growing depth and nutrient availability, and measured resistance to herbivory as well as genetic variation and costs of phlorotannins, putative defensive secondary metabolites, in the brown alga Fucus vesiculosus. Herbivory on algae varied with depth: grazing did not cause losses close to the surface, but, most of the algal production was consumed at the deeper end of the algal belt. The higher the genotypic phlorotannin content the less damage the genotype received implying that phlorotannins acted as a resistance trait. Production of phlorotannins was associated with costs for growth. Consistent with the prediction that the cost of defense will be greatest when resources are limiting, the cost appeared only in the deep end of the algal belt where growth was slowed down. Phlorotannins displayed phenotypic plasticity; the three factors influenced phlorotannins interactively, with the main tendencies of nutrient enrichment decreasing and herbivory and increasing depth increasing phlorotannins. Despite this plasticity, variation of phlorotannins was mainly due to the genotype of algae. These results emphasize the role of herbivory as a selective agent for algal defenses and the importance of genetic variation in the constitutive level of phlorotannins in interactions with natural enemies. The cost of phlorotannins may constrain the evolution of resistance in environments where growth is limited by light availability.
The natural link between Europe and Africa – 2.1 billion birds on migration
Authors: Hahn Steffen , Bauer Silke , Liechti Felix
Published: January 2009

The Palaearctic–African migration system comprises enormous numbers of birds travelling between Europe and Africa twice each year. Migratory birds may form strong links between the two continents given they can act as both transport vehicles for parasites and diseases as well as temporary consumers with increased food demand to fuel their flight. Knowing the number of migrating birds is crucial if such links are to be quantified. We estimate that today approximately 2.1 billion songbirds and near‐passerine birds migrate from Europe to Africa in autumn, 73% of which are accounted for by just 16 species. This number is only half the estimate from the 1950s in the only other assessment to date. The discrepancy is mainly caused by the limited information on population sizes in the past. Our estimated number of migrants is highly dependent on the accuracy of the underlying estimates of breeding population sizes, as well as breeding parameters in species with relatively high reproductive output. The updated figures quantify and emphasize the strong natural connection between Africa and Europe, which has important implications for manifold research topics including those related to climate change, human health and biological conservation.
Indirect effects of heterospecific interactions on progeny size through maternal stress
Authors: McCormick Mark I.
Published: January 2009

Maternal effects are increasingly being recognized as an important pre‐natal source of life history variation in the next generation. The present study uses a field experiment to explore the influence of heterospecific interactions on the reproductive output and offspring characteristics of a common Indo‐Pacific damselfish,Pomacentrus amboinensis. On the Great Barrier Reef pairs of breedingP. amboinensiswere placed on isolated patch reefs and to half of the pairs resource competitors (other planktivorous damselfishes), and predators of eggs and juveniles were added. Females inhabiting patches with heterospecifics had more aggressive interactions and higher levels of the stress hormone, cortisol. Neither the number of clutches nor number of eggs produced differed among treatments. The size of larvae at hatching was found to be reduced as a result of the stress associated with increased interactions with heterospecific and the transfer of cortisol to offspring. This stress‐associated mechanism appears to be an important and directional source of life history variability, but the individual nature of the maternal response is likely to result in a conclusion of a diversified bet hedging reproductive strategy when viewed at the local population level. These findings highlight the complex determinants of individual success and the important role of parental well‐being in the population dynamics of the next generation.
Quantitative analysis of the maxilla and the mandible in hyper‐ and hypodivergent skeletal class II pattern
Authors: Nair R , Deguchi T Sr , Li X , Katashiba S , Chan YH
Published: January 2009

Structured Abstract

Authors –  Nair R, Deguchi T Sr., Li X, Katashiba S, Chan YH

Objectives –  To examine the volumetric (size) difference in the maxilla and the mandible of hyper‐ and hypodivergent skeletal patterns in Angle class II malocclusion.

Design –  Descriptive retrospective study. The hypothesis is that a hypodivergent mandible has a larger size than a hyperdivergent mandible.

Setting and Sample Population –  Using cone‐beam computed tomography, 20 subjects with Angle class II malocclusion were classified into two groups; 10 of 20 subjects formed a hyperdivergent group while the rest formed a hypodivergent group.

Material and methods –  Cone‐beam computed tomography images were obtained and processed and 3D volume data was measured by one clinician. Dahlberg’s technique was used to assess the measurement error and significant difference was set at p < 0.05.

Results –  No significant differences were found between the volumes of the maxilla and mandible in both groups. Differences were observed in the ratio of mandibular/maxillary volumes. The hypodivergent group had a significantly larger (p = 0.014) ratio than the hyperdivergent group.

Conclusions –  Maxillary and mandibular volumes differ between hyper‐ and hypodivergent skeletal patterns.
The effect of rainforest fragmentation on species diversity and mimicry ring composition of ithomiine butterflies
Authors: UEHARA‐PRADO MARCIO , FREITAS ANDRÉ V.L.
Published: January 2009

Abstract. 

Subfamily Ithomiinae comprises about 370 species of Neotropical butterflies associated with humid forest habitats from Mexico to northern Argentina. Adult Ithomiinae are central models in many mimicry rings throughout their range, and are assumed to have high potential as bio‐indicators. Here, we compare diversity and composition of Ithomiinae mimicry rings in continuous vs. fragmented landscapes, and evaluate values these butterflies hold for ecological assessment and monitoring of anthropogenic disturbance.

Sampling was carried out at four sites inside a large forest block, the Morro Grande State Reserve, and in five forest fragments in a neighbour‐fragmented landscape. Butterflies were sampled with portable traps, baited with a fermented mixture of banana and sugar cane juice. Sampling was carried out during the period most favourable for the capture of ithomiine butterflies in southeastern Brazil.

There was no difference between landscapes in species richness and diversity index, but dominance index, and the distributions of tribes and mimicry rings between them was clearly different. The higher average light intensity in the understorey of fragments could explain in part the higher abundance of mimicry patterns typical of open sunny habitats, and concomitantly reduced abundance of clearwing mimicry patterns, typical of shaded habitats. These results confirm the potential of ithomiine assemblages as biological indicators of habitat quality.
Changes in phenology of hoverflies in a central England garden
Authors: GRAHAM‐TAYLOR LYN G. , STUBBS ALAN E. , BROOKE M. de L.
Published: January 2009

Abstract. 

Hoverfly data, obtained from 20 species during 1991–2007 from a single garden in Peterborough, England, were analysed to test for temporal trends in timing of first and last appearance, flight‐period length and maximum number.

During this period of climate warming, first appearance in spring has become significantly earlier for three species and flight period longer for a different set of three species.

Key correlates of first appearance date and flight‐period length were winter temperature, which increased over the study period, and spring temperature which showed a non‐significant warming trend. Wetter summers also marginally lengthened the flight period. In addition, there were significant year effects, suggestive of population responses to changing climate independent of prevailing temperature.

However, there was little evidence that last appearances in autumn have become later, and maximum numbers have not increased.

These trends match those reported from other, better‐studied taxa.
Efficient tournaments within teams
Authors: Gershkov Alex , Li Jianpei , Schweinzer Paul
Published: January 2009

We analyze incentive problems in team and partnership structures where the only available information to condition a contract on is a partial and noisy ranking which specifies who comes first in efforts among the competing partners. This enables us to ensure both first‐best efficient effort levels for all partners and the redistribution of output only among partners. Our efficiency result is obtained for a wide range of cost and production functions.
Costly participation and heterogeneous preferences in informational committees
Authors: Cai Hongbin
Published: January 2009

Informational committees are groups of people who are designated to gather information. This article develops a simple model of committee size based on costly participation and preference heterogeneity. In a setting in which the information structure and policy preferences are both represented by normal random variables, I characterize an equilibrium under the mean decision rule and derive the optimal committee size. I show that when effort costs are sufficiently high, preference heterogeneity can provide members additional incentives to gather information, and thus the optimal committee size and the principal's expected payoff can increase in the heterogeneity of committee members' policy preferences.
Foot Segment Kinematics During Normal Walking Using a Multisegment Model of the Foot and Ankle Complex
Authors: Jenkyn Thomas R. , Anas Kiersten , Nichol Alexander
Published: January 2009

Gait analysis using optical tracking equipment has been demonstrated to be a clinically useful tool for measuring three-dimensional kinematics and kinetics of the human body. However, in current practice, the foot is treated as a single rigid segment that articulates with the lower leg, meaning the motions of the joints of the foot cannot be measured. A multisegment kinematic model of the foot was developed for use in a gait analysis laboratory. The foot was divided into hindfoot, talus, midfoot, and medial and lateral forefoot segments. Six functional joints were defined: Ankle and subtalar joints, frontal and transverse plane motions of the hindfoot relative to midfoot, supination-pronation twist of the forefoot relative to midfoot, and medial longitudinal arch height-to-length ratio. Twelve asymptomatic subjects were tested during barefoot walking with a six-camera optical stereometric system and passive markers organized in triads. Repeatability of reported motions was tested using coefficients of multiple correlation. Ankle and subtalar joint motions and twisting of the forefoot were most repeatable. Hindfoot motions were least repeatable both within subjects and between subjects. Hindfoot and forefoot pronations in the frontal place were found to coincide with dropping of the medial longitudinal arch between early to midstance, followed by supination and rising of the arch in late stance and swing phase. This multisegment foot model overcomes a major shortcoming in current gait analysis practice—the inability to measure motion within the foot. Such measurements are crucial if gait analysis is to remain relevant in orthopaedic and rehabilitative treatment of the foot and ankle.
A Mechanical Model of the Human Ankle in the Transverse Plane During Straight Walking: Implications for Prosthetic Design
Authors: Glaister Brian C. , Schoen Jason A. , Orendurff Michael S. , Klute Glenn K.
Published: January 2009

In order to protect sensitive residual limb soft tissues, lower limb prostheses need to control torsional loads during gait. To assist with the design of a torsional prosthesis, this paper used simple mechanical elements to model the behavior of the human ankle in the transverse plane during straight walking. Motion capture data were collected from ten able-bodied subjects walking straight ahead at self-selected walking speeds. Gait cycle data were separated into four distinct states, and passive torsional springs and dampers were chosen to model the behavior in each state. Since prosthetic design is facilitated by simplicity, it was desirable to investigate if elastic behavior could account for the physiological ankle moment and include viscous behavior only if necessary to account for the inadequacies of the spring model. In all four states, a springlike behavior was able to account for most of the physiological ankle moments, rendering the use of a damper unnecessary. In State 1, a quadratic torsional spring was chosen to model the behavior, while linear torsional springs were chosen for States 2–4. A prosthetic system that actively changes stiffness could be able to replicate the physiological behavior of the human ankle in the transverse plane. The results of this study will contribute to the mechanical design and control of a biomimetic torsional prosthesis for lower limb amputees.
Motion of a Single Newtonian Liquid Drop Through Quiescent Immiscible Visco-Elastic Liquid: Shape and Eccentricity
Authors: Gupta Ritu , Wanchoo R. K.
Published: January 2009

The shape of a single Newtonian liquid drop moving freely under gravity in quiescent non-Newtonian liquid (visco-inelastic and visco-elastic) has been studied. Strong effect of fluid elasticity on the shape of Newtonian liquid drop has been observed. Based on experimental observations, a shape regime graph has been suitably modified for elastic fluids. Correlations have also been proposed for the prediction of eccentricity of the Newtonian liquid drop moving through a non-Newtonian visco-elastic liquid.
Draxin, a Repulsive Guidance Protein for Spinal Cord and Forebrain Commissures
Authors: Islam Shahidul M. , Shinmyo Yohei , Okafuji Tatsuya , Su Yuhong , Naser Iftekhar Bin , Ahmed Giasuddin , Zhang Sanbing , Chen Sandy , Ohta Kunimasa , Kiyonari Hiroshi , Abe Takaya , Tanaka Satomi , Nishinakamura Ryuichi , Terashima Toshio , Kitamura Toshio , Tanaka Hideaki
Published: January 2009

Axon guidance proteins are critical for the correct wiring of the nervous system during development. Several axon guidance cues and their family members have been well characterized. More unidentified axon guidance cues are assumed to participate in the formation of the extremely complex nervous system. We identified a secreted protein, draxin, that shares no homology with known guidance cues. Draxin inhibited or repelled neurite outgrowth from dorsal spinal cord and cortical explants in vitro. Ectopically expressed draxin inhibited growth or caused misrouting of chick spinal cord commissural axons in vivo.
draxin
knockout mice showed defasciculation of spinal cord commissural axons and absence of all forebrain commissures. Thus, draxin is a previously unknown chemorepulsive axon guidance molecule required for the development of spinal cord and forebrain commissures.
A Polymorphism in
npr-1
Is a Behavioral Determinant of Pathogen Susceptibility in
C. elegans
Authors: Reddy Kirthi C. , Andersen Erik C. , Kruglyak Leonid , Kim Dennis H.
Published: January 2009

The nematode
Caenorhabditis elegans
responds to pathogenic bacteria with conserved innate immune responses and pathogen avoidance behaviors. We investigated natural variation in
C. elegans
resistance to pathogen infection. With the use of quantitative genetic analysis, we determined that the pathogen susceptibility difference between the laboratory wild-type strain N2 and the wild isolate CB4856 is caused by a polymorphism in the
npr-1
gene, which encodes a homolog of the mammalian neuropeptide Y receptor. We show that the mechanism of NPR-1–mediated pathogen resistance is through oxygen-dependent behavioral avoidance rather than direct regulation of innate immunity. For
C. elegans
, bacteria represent food but also a potential source of infection. Our data underscore the importance of behavioral responses to oxygen levels in finding an optimal balance between these potentially conflicting cues.
Early Lunar Magnetism
Authors: Garrick-Bethell Ian , Weiss Benjamin P. , Shuster David L. , Buz Jennifer
Published: January 2009

It is uncertain whether the Moon ever formed a metallic core or generated a core dynamo. The lunar crust and returned samples are magnetized, but the source of this magnetization could be meteoroid impacts rather than a dynamo. Here, we report magnetic measurements and
40
Ar/
39
Ar thermochronological calculations for the oldest known unshocked lunar rock, troctolite 76535. These data imply that there was a long-lived field on the Moon of at least 1 microtesla ∼4.2 billion years ago. The early age, substantial intensity, and long lifetime of this field support the hypothesis of an ancient lunar core dynamo.
Role of Toll-Like Receptors in Activation of Porcine Alveolar Macrophages by Porcine Reproductive and Respiratory Syndrome Virus
Authors: Miller Laura C. , Lager Kelly M. , Kehrli Marcus E.
Published: January 2009

Control of virus replication initially depends on rapid activation of the innate immune response. Toll-like receptor (TLR) ligands are potent inducers of innate immunity against viral infections. Porcine reproductive and respiratory syndrome virus (PRRSV), a positive-sense RNA virus, initiates infection in porcine alveolar macrophages (PAMs), elicits weak immune responses, and establishes a persistent infection. To understand the role of single-stranded RNA and double-stranded RNA (dsRNA) intermediates in eliciting host immunity, we sought to determine if TLRs, particularly those that respond to viral molecular patterns, are involved in PRRSV infection. Activation of TLR3 in PAMs with dsRNA increased gene expression for alpha interferon and suppressed PRRSV infectivity. In contrast, TLR4 activation by the treatment of PAMs with lipopolysaccharide did not influence PRRSV infectivity.
Role of SCC
mec
Type in Outcome of
Staphylococcus aureus
Bacteremia in a Single Medical Center
Authors: Ganga Roopa , Riederer Kathleen , Sharma Mamta , Fakih Mohamad G. , Johnson Leonard B. , Shemes Stephen , Khatib Riad
Published: January 2009

Staphylococcus aureus
virulence factors may determine infection presentation. Whether SCC
mec
type-associated factors play a role in
S. aureus
bacteremia is unclear. We conducted a prospective observation of adult inpatients with
S. aureus
bacteremia (1 November 2005 to 31 December 2006), performed SCC
mec
typing of methicillin-resistant
S. aureus
(MRSA) isolates, and stratified the results according to SCC
mec
type. We studied 253 patients. MRSA accounted for 163 (64.4%) cases. The illness severity index was similar in MRSA and methicillin-sensitive
S. aureus
(MSSA) cases. MRSA caused higher in-hospital mortality (23.9% versus 8.9%;
P
= 0.003), longer bacteremia (4.7 ± 6.5 days versus 2.7 ± 2.9 days;
P
= 0.01), but similar metastatic infection (14.7% versus 15.6%). Stratifying the results according to SCC
mec
type revealed significant differences. SCC
mec
type II caused highest mortality (33.3%) versus type IVa (13.5%), other MRSA (12.5%), and MSSA (8.9%). SCC
mec
IVa produced the highest metastatic infection (26.9% versus 9.1% [SCC
mec
II], 8.3% [other MRSA], and 15.6% [MSSA]). Persistent bacteremia (≥7 days) was similar in all SCC
mec
types (16.7 to 20.7%); each exceeded MSSA (6.7%;
P
= 0.05). In multivariate analysis, SCC
mec
II was a predictor of mortality (odds ratio [OR] = 3.73; 95% confidence interval [CI] = 1.81 to 7.66;
P
= 0.009), SCC
mec
IVa was a predictor of metastatic infection (OR = 3.52; CI = 1.50 to 8.23;
P
= 0.004), and MRSA (independent of SCC
mec
type) was a predictor of persistent bacteremia (OR = 4.16; CI = 1.47 to 11.73;
P
= 0.007). These findings suggest that SCC
mec
-associated virulence factors play a role in the outcome of
S. aureus
bacteremia. Additional studies are needed to identify which virulence factors are the determinants of increased mortality with SCC
mec
type II and metastatic infection with SCC
mec
type IVa.
Growth of Adenocarcinoma on Routine Microbiological Media Inoculated with Fluid from a Pleural Effusion in an 82-Year-Old Female
Authors: Muldrew Kenneth L. , Edberg Stephen C.
Published: January 2009

We report the first documented case of adenocarcinoma cell growth on routine microbiological media. Pleural fluid culture from an 82-year-old female showed colonies with fried egg appearance on routine microbiological media that were negative for bacterial microorganisms. Stains of the colonies demonstrated clusters of viable neoplastic cells.
Unreliable Detection of
Mycobacterium xenopi
by the Nonradiometric Bactec MGIT 960 Culture System
Authors: Piersimoni Claudio , Nista Domenico , Bornigia Stefano , Gherardi Giancarlo
Published: January 2009

From June 2006 to December 2007, 3,648 clinical specimens consecutively received for mycobacterial culture were investigated. Each processed sample was inoculated into Bactec MGIT 960 liquid medium and a Löwenstein-Jensen slant. Tubes that were flagged as positive by the instrument as well as those determined to be negative after 42 days of incubation were removed, visually inspected for growth, and checked for the presence of acid-fast bacilli. Three hundred sixty-nine mycobacterial strains were recovered; of the 44
Mycobacterium xenopi
isolates recovered by MGIT medium, only 13 were detected by the instrument (
P
< 0.0001). Most tubes yielding
M. xenopi
exhibited a peculiar pattern of growth characterized by a scant number of round, yellow-pigmented granules instead of the fine, evenly dispersed clumps usually observed for mycobacteria. It is suggested to check all individual tubes discarded by the MGIT 960 system at the end of the incubation period to prevent a significant amount of previously undetected growth from being missed.
Diagnostic Accuracy of In-House PCR for Pulmonary Tuberculosis in Smear-Positive Patients: Meta-Analysis and Metaregression
Authors: Greco S. , Rulli M. , Girardi E. , Piersimoni C. , Saltini C.
Published: January 2009

In-house PCR (hPCR) could speed differential diagnosis between tuberculosis (TB) and nontuberculous mycobacterial disease in patients with positive smears and pulmonary infiltrates, but its reported accuracy fluctuates across studies. We conducted a systematic review and meta-analysis of hPCR sensitivity and specificity for smear-positive TB diagnosis, using culture as the reference standard. After searching English language studies in MEDLINE and EMBASE, we estimated cumulative accuracy by means of summary receiver operating characteristic analysis. The possible influence of hPCR procedures and study methodological features on accuracy was explored by univariate metaregression, followed by multivariate adjustment of items selected as significant. Thirty-five articles (1991 to 2006) met the inclusion criteria. The pooled estimates of the diagnostic odds ratio, sensitivity, and specificity (random-effect model) were, respectively, 60 (confidence interval [CI], 29 to 123), 0.96 (CI, 0.95 to 0.97), and 0.81 (CI, 0.78 to 0.84), but significant variations (mainly in specificity) limit their clinical applicability. The quality of the reference test, the detection method, and real-time PCR use explained some of the observed heterogeneity. Probably due to the limited study power of our meta-analysis and to the wide differences in both laboratory techniques and methodological quality, only real-time PCR also displayed a positive impact on accuracy in the multivariate model. Currently, hPCR can be confidently used to exclude TB in smear-positive patients, but its low specificity could lead to erroneous initiation of therapy, isolation, and contact investigation. As the inclusion of samples from treated patients could have artificially reduced specificity, future studies should report mycobacterial-culture results for each TB and non-TB sample analyzed.
Mengovirus-Induced Rearrangement of the Nuclear Pore Complex: Hijacking Cellular Phosphorylation Machinery
Authors: Bardina Maryana V. , Lidsky Peter V. , Sheval Eugene V. , Fominykh Ksenia V. , van Kuppeveld Frank J. M. , Polyakov Vladimir Y. , Agol Vadim I.
Published: January 2009

Representatives of several picornavirus genera have been shown previously to significantly enhance noncontrollable bidirectional exchange of proteins between nuclei and cytoplasm. In enteroviruses and rhinoviruses, enhanced permeabilization of the nuclear pores appears to be primarily due to proteolytic degradation of some nucleoporins (protein components of the pore), whereas this effect in cardiovirus-infected cells is triggered by the leader (L) protein, devoid of any enzymatic activities. Here, we present evidence that expression of L alone was sufficient to cause permeabilization of the nuclear envelope in HeLa cells. In contrast to poliovirus, mengovirus infection of these cells did not elicit loss of nucleoporins Nup62 and Nup153 from the nuclear pore complex. Instead, nuclear envelope permeabilization was accompanied by hyperphosphorylation of Nup62 in cells infected with wild-type mengovirus, whereas both of these alterations were suppressed in L-deficient virus mutants. Since phosphorylation of Nup62 (although less prominent) did accompany permeabilization of the nuclear envelope prior to its mitotic disassembly in uninfected cells, we hypothesize that cardiovirus L alters the nucleocytoplasmic traffic by hijacking some components of the normal cell division machinery. The variability and biological significance of picornaviral interactions with the nucleocytoplasmic transport in the infected cells are discussed.
Dendritic Cells Are Required for Optimal Activation of Natural Killer Functions following Primary Infection with Herpes Simplex Virus Type 1
Authors: Kassim Sadik H. , Rajasagi Naveen K. , Ritz Barry W. , Pruett Stephen B. , Gardner Elizabeth M. , Chervenak Robert , Jennings Stephen R.
Published: January 2009

Natural killer (NK) cells play an important role in the optimal clearance of herpes simplex virus type 1 (HSV-1) infection in mice. Activated NK cells function via cytokine secretion or direct cytolysis of target cells; dendritic cells (DCs) are thought to make critical contributions in the activation of both of these functions. Yet, the magnitude and physiological relevance of DC-mediated NK cell activation in vivo is not completely understood. To examine the contribution of DC help in regulating NK cell functions after infection with HSV-1, we utilized a transgenic mouse model that allows the transient ablation of DCs. Using this approach, it was found that the gamma interferon (IFN-γ) expression potential of NK cells is quantitatively and qualitatively impaired in the absence of DCs. With regard to priming of NK cytolytic functions, the ablation of DCs did not significantly affect cytotoxic protein expression by NK cells. An in vivo cytolytic assay did, however, reveal impairments in the magnitude of NK cell cytotoxicity. Overall, this study provides direct evidence that functional DCs are required for optimal IFN-γ expression and cytolytic function by NK cells following infection with HSV-1.
Pathogenesis of 1918 Pandemic and H5N1 Influenza Virus Infections in a Guinea Pig Model: Antiviral Potential of Exogenous Alpha Interferon To Reduce Virus Shedding
Authors: Van Hoeven Neal , Belser Jessica A. , Szretter Kristy J. , Zeng Hui , Staeheli Peter , Swayne David E. , Katz Jacqueline M. , Tumpey Terrence M.
Published: January 2009

Although highly pathogenic avian influenza H5N1 viruses have yet to acquire the ability to transmit efficiently among humans, the increasing genetic diversity among these viruses and continued outbreaks in avian species underscore the need for more effective measures for the control and prevention of human H5N1 virus infection. Additional small animal models with which therapeutic approaches against virulent influenza viruses can be evaluated are needed. In this study, we used the guinea pig model to evaluate the relative virulence of selected avian and human influenza A viruses. We demonstrate that guinea pigs can be infected with avian and human influenza viruses, resulting in high titers of virus shedding in nasal washes for up to 5 days postinoculation (p.i.) and in lung tissue of inoculated animals. However, other physiologic indicators typically associated with virulent influenza virus strains were absent in this species. We evaluated the ability of intranasal treatment with human alpha interferon (α-IFN) to reduce lung and nasal wash titers in guinea pigs challenged with the reconstructed 1918 pandemic H1N1 virus or a contemporary H5N1 virus. IFN treatment initiated 1 day prior to challenge significantly reduced or prevented infection of guinea pigs by both viruses, as measured by virus titer determination and seroconversion. The expression of the antiviral Mx protein in lung tissue correlated with the reduction of virus titers. We propose that the guinea pig may serve as a useful small animal model for testing the efficacy of antiviral compounds and that α-IFN treatment may be a useful antiviral strategy against highly virulent strains with pandemic potential.
Roles of Polypyrimidine Tract Binding Proteins in Major Immediate-Early Gene Expression and Viral Replication of Human Cytomegalovirus
Authors: Cosme Ruth S. Cruz , Yamamura Yasuhiro , Tang Qiyi
Published: January 2009

Human cytomegalovirus (HCMV), a member of the β subgroup of the family
Herpesviridae
, causes serious health problems worldwide. HCMV gene expression in host cells is a well-defined sequential process: immediate-early (IE) gene expression, early-gene expression, DNA replication, and late-gene expression. The most abundant IE gene, major IE (MIE) gene pre-mRNA, needs to be spliced before being exported to the cytoplasm for translation. In this study, the regulation of MIE gene splicing was investigated; in so doing, we found that polypyrimidine tract binding proteins (PTBs) strongly repressed MIE gene production in cotransfection assays. In addition, we discovered that the repressive effects of PTB could be rescued by splicing factor U2AF. Taken together, the results suggest that PTBs inhibit MIE gene splicing by competing with U2AF65 for binding to the polypyrimidine tract in pre-mRNA. In intron deletion mutation assays and RNA detection experiments (reverse transcription [RT]-PCR and real-time RT-PCR), we further observed that PTBs target all the introns of the MIE gene, especially intron 2, and affect gene splicing, which was reflected in the variation in the ratio of pre-mRNA to mRNA. Using transfection assays, we demonstrated that PTB knockdown cells induce a higher degree of MIE gene splicing/expression. Consistently, HCMV can produce more viral proteins and viral particles in PTB knockdown cells after infection. We conclude that PTB inhibits HCMV replication by interfering with MIE gene splicing through competition with U2AF for binding to the polypyrimidine tract in MIE gene introns.
MEMRISTOR OSCILLATORS
Authors: ITOH MAKOTO , CHUA LEON O.
Published: January 2009

The memristor has attracted phenomenal worldwide attention since its debut on 1 May 2008 issue of Nature in view of its many potential applications, e.g. super-dense nonvolatile computer memory and neural synapses. The Hewlett–Packard memristor is a passive nonlinear two-terminal circuit element that maintains a functional relationship between the time integrals of current and voltage, respectively, viz. charge and flux. In this paper, we derive several nonlinear oscillators from Chua's oscillators by replacing Chua's diodes with memristors.
IDENTIFICATION AND REALIZATION OF LINEARLY SEPARABLE BOOLEAN FUNCTIONS VIA CELLULAR NEURAL NETWORKS
Authors: MI BO , LIAO XIAOFENG , LI CHUANDONG
Published: January 2009

In this paper, an effective method for identifying and realizing linearly separable Boolean functions (LSBF) of six variables via Cellular Neural Networks (CNN) is presented. We characterized the basic relations between CNN genes and the truth table of Boolean functions. In order to implement LSBF independently, a directed graph is employed to sort the offset levels according to the truth table. Because any linearly separable Boolean gene (LSBG) can be derived separately, our method will be more practical than former schemes [Chen & Chen, 2005a, 2005b; Chen & He, 2006].
SYNCHRONIZATION ERRORS AND UNIFORM SYNCHRONIZATION WITH AN ERROR BOUND FOR CHAOTIC SYSTEMS
Authors: LIU BIN , HILL DAVID J. , CHEN GUANRONG
Published: January 2009

This paper investigates the problem of estimating synchronization errors and its application to uniform synchronization with an error bound for the general master-slave chaos synchronization scheme via feedback control, which is subjected to disturbances by unknown but bounded channel noise. Based on the Lyapunov function and nonlinear parametric variation techniques, estimation formulae for synchronization errors are derived. It is possible to synchronize two master-slave chaotic systems with a relatively small error bound, even in the case with unknown but bounded noisy disturbances. After the theoretical analysis, some representative examples and their numerical simulations are given for illustration.