bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity of scattering and absorbing aerosol direct radiative forcing to physical climate factors
Authors: Ocko Ilissa B. , Ramaswamy V. , Ginoux Paul , Ming Yi , Horowitz Larry W.
Published: September 2012

The direct radiative forcing of the climate system includes effects due to scattering and absorbing aerosols. This study explores how important physical climate characteristics contribute to the magnitudes of the direct radiative forcings (DRF) from anthropogenic sulfate, black carbon, and organic carbon. For this purpose, we employ the GFDL CM2.1 global climate model, which has reasonable aerosol concentrations and reconstruction of twentieth‐century climate change. Sulfate and carbonaceous aerosols constitute the most important anthropogenic aerosol perturbations to the climate system and provide striking contrasts between primarily scattering (sulfate and organic carbon) and primarily absorbing (black carbon) species. The quantitative roles of cloud coverage, surface albedo, and relative humidity in governing the sign and magnitude of all‐sky top‐of‐atmosphere (TOA) forcings are examined. Clouds reduce the global mean sulfate TOA DRF by almost 50%, reduce the global mean organic carbon TOA DRF by more than 30%, and increase the global mean black carbon TOA DRF by almost 80%. Sulfate forcing is increased by over 50% as a result of hygroscopic growth, while high‐albedo surfaces are found to have only a minor (less than 10%) impact on all global mean forcings. Although the radiative forcing magnitudes are subject to uncertainties in the state of mixing of the aerosol species, it is clear that fundamental physical climate characteristics play a large role in governing aerosol direct radiative forcing magnitudes.
Influence of the spatial extent and resolution of input data on soil carbon models in Florida, USA
Authors: Vasques Gustavo M. , Grunwald S. , Myers D. Brenton
Published: September 2012

Understanding the causes of spatial variation of soil carbon (C) has important implications for regional and global C dynamics studies. Soil C predictive models can identify sources of C variation, but may be influenced by scale parameters, including the spatial extent and resolution of input data. Our objective was to investigate the influence of these scale parameters on soil C spatial predictive models in Florida, USA. We used data from three nested spatial extents (Florida, 150,000 km2; Santa Fe River watershed, 3,585 km2; and University of Florida Beef Cattle Station, 5.58 km2) to derive stepwise linear models of soil C as a function of 24 environmental properties. Models were derived within the three extents and for seven resolutions (30–1920 m) of input environmental data in Florida and in the watershed, then cross‐evaluated among extents and resolutions, respectively. The quality of soil C models increased with an increase in the spatial extent (R2 from 0.10 in the cattle station to 0.61 in Florida) and with a decrease in the resolution of input data (R2 from 0.33 at 1920‐m resolution to 0.61 at 30‐m resolution in Florida). Soil and hydrologic variables were the most important across the seven resolutions both in Florida and in the watershed. The spatial extent and resolution of environmental covariates modulate soil C variation and soil‐landscape correlations influencing soil C predictive models. Our results provide scale boundaries to observe environmental data and assess soil C spatial patterns, supporting C sequestration, budgeting and monitoring programs.
Time‐reversal techniques for MISO and MIMO wireless communication systems
Authors: Fouda Ahmed E. , Teixeira Fernando L. , Yavuz Mehmet E.
Published: September 2012

We consider the application of different time‐reversal (TR) signal processing and beamforming techniques to multiple‐input single‐output (MISO) and multiple‐input multiple‐output (MIMO) wireless communication systems. Conventional TR beamforming provides spatial focusing at the intended receiver; however, it does not yield perfect channel equalization. Time‐reversed pilot can be normalized to provide perfect equalization at the expense of power level. This equalization is particularly important for high data rates where the bit error rate performance is dominated by internal noise due to intersymbol interference. To increase physical layer covertness, TR beamforming is combined with the multiple‐signal‐classification (MUSIC) technique to produce null fields at eavesdroppers. This technique is also applied to MIMO setups to eliminate interuser interference and hence increase system capacity. Differential TR is used to obtain and update pilot signals for passive moving receivers, i.e., those that cannot (or do not) transmit pilot signals. Time‐reversed differential backscattered signal is able to provide satisfactory spatial and temporal focusing at the moving receiver.
Facilitating Family Literacy Activities in Mexico
Authors: Dynia Jaclyn M. , Pentimonti Jill M. , Pratt Amy , Justice Laura M.
Published: September 2012

International collaborations allow for an important exchange and flow of ideas. Over the past two years, our team of researchers, clinicians, and graduate students has collaborated with the Solyluna School. The Solyluna School is in Merida, Mexico, and serves children with severe language and cognitive impairments. The context of the Solyluna School is central to our efforts in this area, as the Solyluna School has sought out ways to increase the family literacy activities for the students enrolled in the school. Furthermore, family literacy activities within the Yucatan context, through the small amount of research available, have been shown to be minimal. Using our experiences as a backdrop, we will discuss suggestions for practice.
Effects of Luminance on Dynamic Random-Dot Correlogram Evoked Visual Potentials
Authors: Markó Katalin , Mikó-Barath Eszter , Kiss Huba J , Török Béla , Jandó Gabor
Published: September 2012

Although dynamic random-dot correlogram evoked visual potentials (DRDC-VEPs) are a three-decade-old method to detect the cortical binocularity in humans and animals, our knowledge of the influence of fundamental stimulus parameters and the underlying cerebral processing mechanisms has remained limited. The purpose of this study was to evaluate the effect of luminance on DRDC-VEPs in adults. The variability and detectability of DRDC-VEPs were investigated under different stimulus luminance conditions with neutral density filters. Our results have demonstrated that DRDC-VEPs can be evoked in a wide luminance range, and the response amplitude was practically independent of luminance between 4.75 cd m−2 and 0.015 cd m−2, while DRDC-VEP latencies showed a strong linear correlation with log luminance. There is, however, a limit (0.06 cd m−2) below which DRDC-VEPs are not reliably recordable. Luminance reduction-induced delays in DRDC-VEP latencies cannot be explained simply by retinal mechanisms, since their regression slope does not follow the course of electroretinogram and cortical evoked potential latencies. Luminance independence of DRDC-VEP amplitude suggests that binocular correlation-processing cortical neurons receive input predominantly from the magnocellular visual pathway.
Effects of Band-Pass Spatial Frequency Filtering of Face and Object Images on the Amplitude of N170
Authors: Collin Charles A , Therrien Megan E , Campbell Kenneth B , Hamm Jeff P
Published: September 2012

Previous studies have suggested that physiological responses are greatest and face recognition performance is best when a band of middle relative spatial frequencies (SFs) is included in stimuli. Conversely, behavioural data suggest that object recognition performance shows comparatively little effect of SF variations. Here, we examine the effects of SF filtering on the amplitude of the N170 ERP component when participants are shown images of faces and objects. Our findings show that with face stimuli the amplitude of N170 exhibits a band-pass modulation function, with responses to middle SFs (around 11 cycles per face) being statistically indistinguishable from responses to full-band faces. In contrast to faces, object stimuli elicited a relatively flat function across much of the spectrum. However, for both faces and objects, middle spatial frequencies were sufficient to elicit the same N170 magnitude as full-band images. Our results with face stimuli are in accordance with previous work examining single-cell and MEG responses. Our results with objects are compatible with previous behavioural work showing a relative robustness of object recognition to SF manipulations. Our findings are novel in showing that the middle band elicits the same N170 as full-band images in both faces and objects.
Heterogeneous nuclear ribonucleoprotein L-like (hnRNPLL) and elongation factor, RNA polymerase II, 2 (ELL2) are regulators of mRNA processing in plasma cells
Authors: Benson Micah J. , Äijö Tarmo , Chang Xing , Gagnon John , Pape Utz J. , Anantharaman Vivek , Aravind L. , Pursiheimo Juha-Pekka , Oberdoerffer Shalini , Liu X. Shirley , Lahesmaa Riitta , Lähdesmäki Harri , Rao Anjana
Published: September 2012

B cells and plasma cells possess distinct RNA processing environments that respectively promote the expression of membrane-associated Ig by B cells versus the secretion of Ig by plasma cells. Through a combination of transcriptional profiling and screening using a lentiviral short-hairpin RNA interference library, we show that both the splicing factor hnRNPLL and the transcription elongation factor ELL2 modulate the ratio of secreted versus membrane-encodingIghg2btranscripts in MPC11 plasmacytoma cell lines. hnRNPLL and ELL2 are both highly expressed in primary plasma cells relative to B cells, but hnRNPLL bindsIghg2bmRNA transcripts and promotes an increase in levels of the membrane-encodingIghg2bisoform at the expense of the secretedIghg2bisoform, whereas ELL2 counteracts this effect and drives Ig secretion by increasing the frequency of the secretedIghg2bisoform. As in T cells, hnRNPLL also alters the splicing pattern of mRNA encoding the adhesion receptor CD44, promoting exon inclusion, and decreasing the overall level of CD44 expression. Further characterization of ELL2-dependent transcription by RNA-Seq revealed that ∼12% of transcripts expressed by plasma cells were differentially processed because of the activities of ELL2, including B-cell maturation antigen BCMA, a receptor with a defined role in plasma cell survival. Taken together, our data identify hnRNPLL and ELL2 as regulators of pre-mRNA processing in plasma cells.
Improving motor performance: Selected aspects of augmented feedback in exercise and health
Authors: Lauber Benedikt , Keller Martin
Published: September 2012

Augmented feedback (AF) can play an important role when learning or improving a motor skill. As research dealing with AF is broad and diverse, the purpose of this review is to provide the reader with an overview of the use of AF in exercise, motor learning and injury prevention research with respect to how it can be presented, its informational content and the limitations. The term ‘augmented’ feedback is used because additional information provided by an external source is added to the task‐intrinsic feedback that originates from a person's sensory system. In recent decades, numerous studies from various fields within sport science (exercise science, sports medicine, motor control and learning, psychology etc.) have investigated the potential influence of AF on performance improvements. The first part of the review gives a theoretical background on feedback in general but particularly AF. The second part tries to highlight the differences between feedback that is given as knowledge of result and knowledge of performance. The third part introduces studies which have applied AF in exercise and prevention settings. Finally, the limitations of feedback research and the possible reasons for the diverging findings are discussed. The focus of this review lies mainly on the positive influence of AF on motor performance. Underlying neuronal adaptations and theoretical assumptions from learning theories are addressed briefly.
On a planar area-preserving curvature flow
Authors: Chao Xiao-Li , Ling Xiao-Ran , Wang Xiao-Liu
Published: September 2012

A classical nonlocal curvature flow preserving the enclosed area is reinvestigated. The uniform upper bound and lower bound of curvature are established for the first time. As a result, a detailed proof is presented for the asymptotic behavior of the flow.
The topology of spaces of polygons
Authors: Farber Michael , Fromm Viktor
Published: September 2012

Let

E

d

(
ℓ
)

E_{d}(\ell )

denote the space of all closed

n
n

-gons in

R

d

\mathbb {R}^{d}

(where

d
≥
2

d\ge 2

) with sides of length

ℓ
1

,
…
,

ℓ
n

\ell _1, \dots , \ell _n

, viewed up to translations. The spaces

E
d

(
ℓ
)

E_d(\ell )

are parameterized by their length vectors

ℓ
=
(

ℓ
1

,
…
,

ℓ
n

)
∈

R

>

n

\ell =(\ell _1, \dots , \ell _n)\in \mathbb {R}^n_{>}

encoding the length parameters. Generically,

E

d

(
ℓ
)

E_{d}(\ell )

is a closed smooth manifold of dimension

(
n
−
1
)
(
d
−
1
)
−
1

(n-1)(d-1)-1

supporting an obvious action of the orthogonal group

O

(
d
)

{ {O}}(d)

. However, the quotient space

E

d

(
ℓ
)

/

O

(
d
)

E_{d}(\ell )/{{O}}(d)

(the moduli space of shapes of

n
n

-gons) has singularities for a generic

ℓ
\ell

, assuming that

d
>
3

d>3

; this quotient is well understood in the low-dimensional cases

d
=
2

d=2

and

d
=
3

d=3

. Our main result in this paper states that for fixed

d
≥
3

d\ge 3

and

n
≥
3

n\ge 3

, the diffeomorphism types of the manifolds

E

d

(
ℓ
)

E_{d}(\ell )

for varying generic vectors

ℓ
\ell

are in one-to-one correspondence with some combinatorial objects – connected components of the complement of a finite collection of hyperplanes. This result is in the spirit of a conjecture of K. Walker who raised a similar problem in the planar case

d
=
2

d=2

.
Sexual dimorphism in size, age, maturation, and growth characteristics of boarfish (Capros aper) in the Northeast Atlantic
Authors: Hüssy Karin , Coad Julie Olivia , Farrell Edward D. , Clausen Lotte W. , Clarke Maurice W.
Published: September 2012

Hüssy, K., Coad, J. O., Farrell, E. D., Clausen, L. W., and Clarke, M. W. 2012. Sexual dimorphism in size, age, maturation, and growth characteristics of boarfish (Capros aper) in the Northeast Atlantic – ICES Journal of Marine Science, 69: 1729–1735. Boarfish (Capros aper) have, in recent years, become of increasing commercial importance due to their apparent increase in abundance in the Northeast Atlantic. This study presents detailed biological information relevant to understanding stock structure and dynamics. Boarfish are a long-lived species that reach a maximum age of >30 years. The size distribution is skewed towards larger sizes, as expected from an unexploited stock with sexual dimorphism, where females are, on average, larger than males. No seasonal effects occur in size distribution and sex ratio, indicating that females and males stay together in shoals throughout the year. Females become increasingly dominant in abundance at larger sizes and older ages. There is no significant difference in length at maturity nor age at maturity between the two sexes, with L50 = 9.7 cm and A50 = 3.4 years. Growth is dimorphic following von Bertalanffy growth characteristics, with a common t0 = –2.897, but significantly different K and Linf values, where females have K = 0.145 and Linf = 16.519 and males have K = 0.181 and Linf = 14.437. The sexual dimorphism in size is thus caused by sex-specific growth and longevity patterns.
Effect of Grain Protein Concentration on Falling Number of Ungerminated Soft White Winter Wheat
Authors: Ross Andrew S. , Flowers Michael D. , Zemetra Robert S. , Kongraksawech Teepakorn
Published: September 2012

Falling number (FN) values below 300 sec in the apparent absence of preharvest sprouting are periodically observed in the U.S. Pacific Northwest (USPNW). Wheat in the USPNW is predominantly soft‐grained and often grown under conditions conducive to low grain protein concentration (GPC). Our hypothesis is that low GPC per se could be responsible for some low FN results and not elevated α‐amylase from either sprouting or late‐maturity amylase. The relationship between FN and GPC was investigated using grain from the 2011 wheat harvest. Soft white winter wheat samples from six locations in Oregon were tested in duplicate. Across the entire sample set, FN and GPC were positively correlated (r = 0.65, P ≤ 0.001). When putatively sprouted samples (FN < 280 sec) were removed from the analysis, the correlation was still apparent (r = 0.69, P ≤ 0.001). Hardness index was also correlated with FN (r = 0.45, P ≤ 0.001). Our preliminary conclusion is that GPC can be a substantial modulator of FN in the putative absence of elevated amylase in soft white winter wheat grown in the USPNW.
Multiple Phytohormone Signals Control the Transcriptional Response to Soybean Aphid Infestation in Susceptible and Resistant Soybean Plants
Authors: Studham Matthew E. , MacIntosh Gustavo C.
Published: September 2012

The soybean aphid (Aphis glycines) is a major phloem-feeding pest of soybean (Glycine max). A. glycines feeding can cause the diversion of photosynthates and transmission of plant viruses, resulting in significant yield losses. In this study, we used oligonucleotide microarrays to characterize the long-term transcriptional response to soybean aphid colonization of two related soybean cultivars, one with the Rag1 aphid-resistance gene and one aphid-susceptible cultivar (without Rag1). Transcriptome profiles were determined after 1 and 7 days of aphid infestation. Our results revealed a susceptible response involving hundreds of transcripts, whereas only one transcript changed in the resistant response to aphids. This nonexistent resistance response might be explained by the fact that many defense-related transcripts are constitutively expressed in resistant plants, whereas these same genes are activated in susceptible plants only during aphid infestation. Analysis of phytohormone-related transcripts in the susceptible response showed different hormone profiles for the two time points, and suggest that aphids are able to suppress hormone signals in susceptible plants. A significant activation of abscissic acid, normally associated with abiotic stress responses, at day 7, might be a decoy strategy implemented by the aphid to suppress effective salicylic acid- and jasmonate-related defenses.
Insights into the Noncoding RNome of Nitrogen-Fixing Endosymbiotic α-Proteobacteria
Authors: Jiménez-Zurdo José I. , Valverde Claudio , Becker Anke
Published: September 2012

Symbiotic chronic infection of legumes by rhizobia involves transition of invading bacteria from a free-living environment in soil to an intracellular state as differentiated nitrogen-fixing bacteroids within the nodules elicited in the host plant. The adaptive flexibility demanded by this complex lifestyle is likely facilitated by the large set of regulatory proteins encoded by rhizobial genomes. However, proteins are not the only relevant players in the regulation of gene expression in bacteria. Large-scale high-throughput analysis of prokaryotic genomes is evidencing the expression of an unexpected plethora of small untranslated transcripts (sRNAs) with housekeeping or regulatory roles. sRNAs mostly act in response to environmental cues as post-transcriptional regulators of gene expression through protein-assisted base-pairing interactions with target mRNAs. Riboregulation contributes to fine-tune a wide range of bacterial processes which, in intracellular animal pathogens, largely compromise virulence traits. Here, we summarize the incipient knowledge about the noncoding RNome structure of nitrogen-fixing endosymbiotic bacteria as inferred from genome-wide searches for sRNA genes in the alfalfa partner Sinorhizobium meliloti and further comparative genomics analysis. The biology of relevant S. meliloti RNA chaperones (e.g., Hfq) is also reviewed as a first global indicator of the impact of riboregulation in the establishment of the symbiotic interaction.
Deep Impact of Ultrasound in the Intensive Care Unit
Authors: Manno Emilpaolo , Navarra Mauro , Faccio Luciana , Motevallian Mohsen , Bertolaccini Luca , Mfochivè Abdou , Pesce Marco , Evangelista Andrea
Published: September 2012

Background

Ultrasound can influence the diagnosis and impact the treatment plan in critical patients. The aim of this study was to determine whether, without encountering major environment- or patient-related limitations, ultrasound examination under a critical care ultrasonography protocol can be performed to detect occult anomalies, to prompt urgent changes in therapy or induce further testing or interventions, and to confirm or modify diagnosis.

Methods

One hundred and twenty-five consecutive patients admitted to a general intensive care unit were assessed under a critical care ultrasonography protocol, and the data were analyzed prospectively. Systematic ultrasound examination of the optic nerve, thorax, heart, abdomen, and venous system was performed at the bedside.

Results

Environmental conditions hampered the examination slightly in 101/125 patients (80.8%), moderately in 20/125 patients (16%), and strongly in 4/125 patients (3.2%). Ultrasonographic findings modified the admitting diagnosis in 32/125 patients (25.6%), confirmed it in 73/125 patients (58.4%), were not effective in confirming or modifying it in 17/125 patients (13.6%), and missed it in 3/125 patients (2.4%). Ultrasonographic findings prompted further testing in 23/125 patients (18.4%), led to changes in medical therapy in 22/125 patients (17.6%), and to invasive procedures in 27/125 patients (21.6%).

Conclusions

In this series of patients consecutively admitted to an intensive care unit, ultrasound examination revealed a high prevalence of unsuspected clinical abnormalities, with the highest number of new ultrasound abnormalities detected in patients with septic shock. As part of rapid global assessment of the patient on admission, our ultrasound protocol holds potential for improving healthcare quality.
Computational analysis and characterization of UCE-like elements (ULEs) in plant genomes
Authors: Kritsas Konstantinos , Wuest Samuel E. , Hupalo Daniel , Kern Andrew D. , Wicker Thomas , Grossniklaus Ueli
Published: September 2012

Ultraconserved elements (UCEs), stretches of DNA that are identical between distantly related species, are enigmatic genomic features whose function is not well understood. First identified and characterized in mammals, UCEs have been proposed to play important roles in gene regulation, RNA processing, and maintaining genome integrity. However, because all of these functions can tolerate some sequence variation, their ultraconserved and ultraselected nature is not explained. We investigated whether there are highly conserved DNA elements without genic function in distantly related plant genomes. We compared the genomes of Arabidopsis thaliana and Vitis vinifera; species that diverged ∼115 million years ago (Mya). We identified 36 highly conserved elements with at least 85% similarity that are longer than 55 bp. Interestingly, these elements exhibit properties similar to mammalian UCEs, such that we named them UCE-like elements (ULEs). ULEs are located in intergenic or intronic regions and are depleted from segmental duplications. Like UCEs, ULEs are under strong purifying selection, suggesting a functional role for these elements. As their mammalian counterparts, ULEs show a sharp drop of A+T content at their borders and are enriched close to genes encoding transcription factors and genes involved in development, the latter showing preferential expression in undifferentiated tissues. By comparing the genomes of Brachypodium distachyon and Oryza sativa, species that diverged ∼50 Mya, we identified a different set of ULEs with similar properties in monocots. The identification of ULEs in plant genomes offers new opportunities to study their possible roles in genome function, integrity, and regulation.
Physicians' perspectives on the uncertainties and implications of chromosomal microarray testing of children and families
Authors: Reiff M , Ross K , Mulchandani S , Propert KJ , Pyeritz RE , Spinner NB , Bernhardt BA
Published: September 2012

Chromosomal microarray analysis (CMA) has improved the diagnostic rate of genomic disorders in pediatric populations, but can produce uncertain and unexpected findings. This article explores clinicians' perspectives and identifies challenges in effectively interpreting results and communicating with families about CMA. Responses to an online survey were obtained from 40 clinicians who had ordered CMA. Content included practice characteristics and perceptions, and queries about a hypothetical case involving uncertain and incidental findings. Data were analyzed using nonparametric statistical tests. Clinicians' comfort levels differed significantly for explaining uncertain, abnormal, and normal CMA results, with lowest levels for uncertain results. Despite clinical guidelines recommending informed consent, many clinicians did not consider it pertinent to discuss the potential for CMA to reveal information concerning biological parentage or predisposition to late‐onset disease, in a hypothetical case. Many non‐genetics professionals ordering CMA did not feel equipped to interpret the results for patients, and articulated needs for education and access to genetics professionals. This exploratory study highlights key challenges in the practice of genomic medicine, and identifies needs for education, disseminated practice guidelines, and access to genetics professionals, especially when dealing with uncertain or unexpected findings.
Review: Immune‐mediated necrotizing myopathies – a heterogeneous group of diseases with specific myopathological features
Authors: Stenzel W. , Goebel H.‐H. , Aronica E.
Published: September 2012

Immune‐mediated necrotizing myopathies (IMNMs) are now well recognized among the so‐called idiopathic inflammatory myopathies (IIMs), which also comprise dermatomyositis (DM), polymyositis (PM), sporadic inclusion body myositis (sIBM) and non‐specific myositis. All of these conditions are defined on the basis of distinct clinical symptoms, in combination with results derived from muscle biopsy and additional data, such as measurement of the serum creatine kinase (CK) level as well as myositis‐associated and myositis‐specific autoantibodies, electromyography (EMG) and modern imaging techniques. Importantly, diagnosis of one of the above mentioned myositis forms implies a specific clinical syndrome or a distinct disease. However, there is considerable clinical heterogeneity, and overlap requiring further diagnostic precision. Classification and subclassification of IIMs are highly debated and the subjects of intense research, especially as clinical trials with anti‐inflammatory agents should follow universally defined and accepted criteria. This review focuses on the description of the spectrum of immune‐mediated necrotizing myopathies with an emphasis on their myopathological features.
Rapid evolution of sex frequency and dormancy as hydroperiod adaptations
Authors: Smith H. A. , Snell T. W.
Published: September 2012

Dormancy can serve as an adaptation to persist in variable habitats and often is coupled with sex. In cyclically parthenogenetic rotifers, an asexual phase enables rapid population growth, whereas sex results in diapausing embryos capable of tolerating desiccation. Few studies have experimentally tested whether sex–dormancy associations in temporary waters reflect evolution in response to the short hydroperiod selecting for diapause ability. Here, we demonstrate evolution of higher propensity for sex and dormancy in ephemeral rotifer cultures mimicking temporary ponds, and lower propensity in permanent cultures. Results are consistent with rapid evolution, with evolutionary changes occurring in a short timeframe (385 days, ≤ 84 generations). We also provide insight into mechanisms for rapid evolution in basal metazoans, discussing potential roles of new mutations, recombination and clonal selection.
Are the national orthopaedic thromboprophylaxis guidelines appropriate?
Authors: Mirkazemi Corinne , Bereznicki Luke R. , Peterson Gregory M.
Published: September 2012

Background

To identify enablers and barriers to thromboprophylaxis prescribing following hip and knee arthroplasty, from the perspective of orthopaedic surgeons.

Methods

An invitation to participate in an online survey was distributed electronically to Arthroplasty Society of Australia members (n = 103). The survey collected demographic details, thromboprophylaxis attitudes and clinical practice of the orthopaedic surgeons, and explored their familiarity with contemporary national and international guidelines.

Results

Twenty‐five surgeons (24%) completed the survey, all male with a median of 20 years of practice as orthopaedic surgeons (range: 8–27 years). Most surgeons (92%) practised predominantly in the private sector, and conducted both hip and knee arthroplasties each month. While all surgeons prescribed chemoprophylaxis following arthroplasty, most surgeons (64%) were uncertain to what extent it would prevent fatal pulmonary embolism (PE). The pharmacological agents of choice were low molecular weight heparin (48%) and aspirin (44%). One‐third of surgeons were not familiar with the National Health and Medical Research Council recommendations for thromboprophylaxis in hip and knee arthroplasty patients. After reviewing a summary of the recommendations, most surgeons (80%) indicated they were inappropriate, commonly citing that they were grounded on an insufficient evidence base and should include aspirin as a sole chemoprophylaxis option.

Conclusion

There are clearly strong barriers to the translation of current thromboprophylaxis guidelines into practice. Many surgeons doubt the effectiveness of chemoprophylaxis to prevent fatal PE, perceive the risk of venous thromboembolism following surgery to be low, are unfamiliar with current national guidelines or believe the guidelines are grounded on inappropriate evidence.
Shared Genomic Segment Analysis: The Power to Find Rare Disease Variants
Authors: Knight Stacey , Abo Ryan P. , Abel Haley J. , Neklason Deborah W. , Tuohy Therese M. , Burt Randall W. , Thomas Alun , Camp Nicola J.
Published: September 2012

Shared genomic segment (SGS) analysis uses dense single nucleotide polymorphism genotyping in high‐risk (HR) pedigrees to identify regions of sharing between cases. Here, we illustrate the power of SGS to identify dominant rare risk variants. Using simulated pedigrees, we consider 12 disease models based on disease prevalence, minor allele frequency and penetrance to represent disease loci that explain 0.2–99.8% of total disease risk. Pedigrees were required to contain ≥15 meioses between all cases and to be HR based on significant excess of disease (P < 0.001 or P < 0.00001). Across these scenarios, the power for a single pedigree ranged widely. Nonetheless, fewer than 10 pedigrees were sufficient for excellent power in the majority of models. Power increased with the risk attributable to the disease locus, penetrance and the excess of disease in the pedigree. Sharing allowing for one sporadic case was uniformly more powerful than sharing using all cases. Furthermore, an SGS analysis using a large attenuated familial adenomatous polyposis pedigree identified a 1.96 Mb region containing the known causal APC gene with genome‐wide significance. SGS is a powerful method for detecting rare variants and a valuable complement to genome‐wide association studies and linkage analysis.
Discovery of new antagonists aimed at discriminating UII and URP‐mediated biological activities: insight into UII and URP receptor activation
Authors: Chatenet D , Létourneau M , Nguyen QT , Doan ND , Dupuis J , Fournier A
Published: September 2012

Background and Purpose

Recent evidence suggested that urotensin II (UII) and its paralog peptide UII‐related peptide (URP) might exert common but also divergent physiological actions. Unfortunately, none of the existing antagonists were designed to discriminate specific UII‐ or URP‐associated actions, and our understanding, on how these two endogenous peptides can trigger different, but also common responses, is limited.

Experimental Approach

Ex vivo rat and monkey aortic ring contraction as well as dissociation kinetics studies using transfected CHO cells expressing the human urotensin (UT) receptors were used in this study.

Key Results

Ex vivo rat and monkey aortic ring contraction studies revealed the propensity of [Pep4]URP to decrease the maximal response of human UII (hUII) without any significant change in potency, whereas no effect was noticeable on the URP‐induced vasoconstriction. Dissociation experiments demonstrated the ability of [Pep4]URP to increase the dissociation rate of hUII, but not URP. Surprisingly, URP, an equipotent UII paralog, was also able to accelerate the dissociation rate of membrane‐bound 125I‐hUII, whereas hUII had no noticeable effect on URP dissociation kinetics. Further experiments suggested that an interaction between the glutamic residue at position 1 of hUII and the UT receptor seems to be critical to induce conformational changes associated with agonistic activation. Finally, we demonstrated that the N‐terminal domain of the rat UII isoform was able to act as a specific antagonist of the URP‐associated actions.

Conclusion

Such compounds, that is [Pep4]URP and rUII(1–7), should prove to be useful as new pharmacological tools to decipher the specific role of UII and URP in vitro but also in vivo.
Neurogenic mucosal bicarbonate secretion in guinea pig duodenum
Authors: Fei G , Fang X , Wang GD , Liu S , Wang XY , Xia Y , Wood JD
Published: September 2012

Background and Purpose

To test a hypothesis that: (i) duodenal pH and osmolarity are individually controlled at constant set points by negative feedback control centred in the enteric nervous system (ENS); (ii) the purinergic P2Y1 receptor subtype is expressed by non‐cholinergic secretomotor/vasodilator neurons, which represent the final common excitatory pathway from the ENS to the bicarbonate secretory glands.

Experimental Approach

Ussing chamber and pH‐stat methods investigated involvement of the P2Y1 receptor in neurogenic stimulation of mucosal bicarbonate (HCO3−) secretion in guinea pig duodenum.

Key Results

ATP increased HCO3− secretion with an EC50 of 160 nM. MRS2179, a selective P2Y1 purinergic receptor antagonist, suppressed ATP‐evoked HCO3− secretion by 47% and Cl− secretion by 63%. Enteric neuronal blockade by tetrodotoxin or exposure to a selective vasoactive intestinal peptide (VIP, VPAC1) receptor antagonist suppressed ATP‐evoked HCO3− secretion by 61 and 41%, respectively, and Cl‐ by 97 and 70% respectively. Pretreatment with the muscarinic antagonist, scopolamine did not alter ATP‐evoked HCO3− or Cl− secretion.

Conclusion and Implications

Whereas acid directly stimulates the mucosa to release ATP and stimulate HCO3− secretion in a cytoprotective manner, neurogenically evoked HCO3− secretion accounts for feedback control of optimal luminal pH for digestion. ATP stimulates duodenal HCO3− secretion through an excitatory action at purinergic P2Y1 receptors on neurons in the submucosal division of the ENS. Stimulation of the VIPergic non‐cholinergic secretomotor/vasodilator neurons, which are one of three classes of secretomotor neurons, accounts for most, if not all, of the neurogenic secretory response evoked by ATP.
For the Win! The Effect of Professional Sports Records on Mayoral Elections
Authors: Miller Michael K.
Published: September 2012

Objective

Voters are more likely to reelect incumbents when political outcomes are positive. Although most scholars assume this is because voters explicitly credit politicians for good outcomes, this article investigates whether some voters simply opt for the status quo when they feel happy.

Methods

To distinguish these two voting models, I propose professional sports records as a proxy for electorate happiness unrelated to political performance. I test the impact of sports performance on incumbent mayoral elections in 39 American cities from 1948 to 2009.

Results

Winning sports records boost incumbents’ vote totals and likelihoods of reelection, exceeding in magnitude the effect of variation in unemployment. In contrast, sports records following elections display no such relationship.

Conclusion

Retrospective voting is partly driven by feelings of happiness unrelated to political appraisal. However, I argue that the implications for democratic accountability are not as dire as many authors claim.
Aspectasaurus (A Dinosaur)?
Authors: Bivard A. , Parsons M.
Published: September 2012

There is mounting evidence that shows how poorly noncontrast computed tomography (NCCT) Alberta Stroke Program Early CT Score (ASPECTS) performs in the first three-hours after stroke onset compared to Diffusion weighted (DWI) magnetic resonance imaging (MRI). It is time to move into the 21st century and use more advanced imaging routinely in hyper-acute stroke assessment. While a useful tool if one is limited to NCCT alone, ASPECTS becomes somewhat superfluous as we now have rapid, validated, automated infarct core and penumbra volumes with either MRI or perfusion CT.
The Desmoteplase in Acute Ischemic Stroke (DIAS) Clinical Trial Program
Authors: Kummer Rüdiger von , Albers Gregory W , Mori Etsuro ,   on behalf of the DIAS Steering Committees†
Published: September 2012

Background

Desmoteplase is a novel, highly fibrin-specific thrombolytic agent in phase III of clinical development. In comparison to alteplase, it has high fibrin selectivity, is associated with minimal or no neurotoxicity, and has no apparent negative effect on the blood–brain barrier. The safety and efficacy of desmoteplase is being studied in the Desmoteplase in Acute Ischemic Stroke clinical trial program. Three studies (Dose Escalation Study of Desmoteplase in Acute Ischemic Stroke, Desmoteplase in Acute Ischemic Stroke, and Desmoteplase in Acute Ischemic Stroke-2) have been completed, two large randomized, double-blind, placebo-controlled, phase III trials are ongoing at >200 sites worldwide (Desmoteplase in Acute Ischemic Stroke-3 and Desmoteplase in Acute Ischemic Stroke-4, n = 800; DIAS-3 and DIAS-4), and a randomized, double-blind, placebo-controlled, dose-escalation phase II trial is ongoing in Japan (Desmoteplase in Acute Ischemic Stroke-Japan, n = 48; DIAS-J).

Aims

The objective of DIAS-3 and DIAS-4 is to evaluate the safety and efficacy of a single IV bolus injection of 90 μg/kg desmoteplase given three- to nine-hours after onset of ischemic stroke (National Institutes of Health Stroke Scale 4–24, age 18–85 years). The objective of DIAS-J is to evaluate the safety and tolerability of desmoteplase 70 and 90 μg/kg three- to nine-hours after ischemic stroke onset in Japanese patients.

Methods

Patients are included with occlusion or high-grade stenosis (thrombolysis in myocardial infarction 0–1) in proximal cerebral arteries on magnetic resonance or computed tomography angiography but excluded with extended ischemic edema on computed tomography or diffusion-weighted imaging.

Conclusion

Desmoteplase is the only thrombolytic agent in late-stage development for acute ischemic stroke that is now tested in patients with proven stroke pathology. The results of the Desmoteplase in Acute Ischemic Stroke clinical trial program will show whether patients with major artery occlusions but not extended ischemic brain damage can be safely and effectively treated up to nine-hours after onset.
THE SCALING OF PULL‐APARTS AND IMPLICATIONS FOR FLUID FLOW IN AREAS WITH STRIKE‐SLIP FAULTS
Authors: Peacock D.C.P. , Anderson M.W.
Published: September 2012

Widths of pull‐aparts between strike‐slip fault segments appear to obey power‐law scaling relationships, at least up to the scale of hundreds of millimetres. Field data from the Liassic limestones of Somerset, UK, are presented and are discussed in relation to fluid flow through rock. The established scaling relationships are used to predict the contributions of different‐sized pull‐aparts to space created by strike‐slip faults. Fluid‐filled pull‐aparts are likely to be significant in hydrocarbon reservoirs affected by strike‐slip faulting because they are sub‐vertical tube‐like structures that may extend through reservoirs and top seals. There are, however, insufficient data to develop a model for permeability along pull‐aparts. Models of fluid flow in rock typically assume a limited range of fracture apertures, so models can be improved by incorporating information on the scaling relationships of the fractures and the contributions of different‐sized fractures to secondary porosity. Also, geomechanical models that assume planar strike‐slip faults are likely to underestimate migration because they do not consider the reduction of compressive stresses at pull‐aparts.
The role of postoperative positioning after DSAEK in preventing graft dislocation
Authors: Sæthre Marit , Drolsum Liv
Published: September 2012

Purpose:  The aim of the study was to evaluate the importance of immediate postoperative supine patient positioning after Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods:  Forty eyes from 40 patients who underwent DSAEK were randomized into two groups: 20 patients sat in a chair for 2 hr postoperatively (group 1), and 20 patients were placed in a supine position (group 2) for the same time interval. At the end of surgery, the anterior chamber was fully filled with air, aiming at an intraocular pressure (IOP) of approximately 20 mmHg. The dislocation rate in the two groups was registered. IOP was measured 2 hr postoperatively and compared with endothelial cell loss at 6 months.

Results:  There was no statistically significant difference in the dislocation rate between the two groups (p = 0.548): two patients (10%) in group 1 and one patient (5%) in group 2. Endothelial cell loss at 6 months was 29.6% and 29.7% in group 1 and 2, respectively. There was no correlation between the IOP 2 hr after surgery and endothelial cell loss at 6 months (p = 0.741).

Conclusion:  Supine positioning does not seem to be of crucial importance in avoiding graft dislocation in DSAEK when the anterior chamber is fully filled with air for 2 hr postoperatively.
Perceived value congruence and team innovation
Authors: Mitchell Rebecca , Parker Vicki , Giles Michelle , Joyce Pauline , Chiang Vico
Published: September 2012

This article develops and tests a model of perceived value congruence effects on team innovation and explores a contingent‐mediated pathway explaining this relationship. Survey data from 346 members of 75 health care teams support a significant relationship between value congruence and innovation. The study data indicate that one of the mechanisms through which perceived value congruence facilitates the generation of novel ideas is through the development of team identification. This mechanism is contingent, however, on the extent to which members focus on profession as a salient social category. Our data support a moderated mediation pathway in which the effect of value congruence is explained through team identification and its interactive effect on innovation.

Practitioner Points

Highlights to organizations, particularly in the health care industry, the importance of perceived value congruence in generating innovative team outcomes, and reinforces the merit of strategies to develop perceived congruence through, for example, leadership and interprofessional education.

Reinforces the value to leaders tasked with innovation of heightening member awareness of professional diversity and associated knowledge differences, within an overarching framework of shared values.
Teasing, depression and unhealthy weight control behaviour in obese children
Authors: Madowitz J. , Knatz S. , Maginot T. , Crow S. J. , Boutelle K. N.
Published: September 2012

What is already known about this subject

Overweight children are teased more than normal weight children.

Weight‐related teasing can come from a variety of sources.

Weight‐related teasing is associated with depression and disordered eating.

What this study adds

Overweight children who experience peer teasing have higher levels of depression and unhealthy weight control behaviours than those who are not teased by peers.

Overweight children who are bothered by weight‐related teasing have higher levels of depression than those who are not bothered by weight‐related teasing.

Background

Data were taken from 80 obese children (mean age = 10.03 years; mean body mass index = 27.37; %white = 29.37%; %female = 58.8%). Self‐report surveys were used to collect data on rates of depressive symptoms, unhealthy weight control behaviours (UWCBs), teasing, sources of teasing and how much the teasing bothered the child.

Objectives

This study aimed to evaluate relationships between weight‐related teasing and UWCBs and depression in obese children. Teasing by peers and/or family, negative feelings due to teasing, frequency of teasing, and number of teasing sources reported and associations with UWCBs and depression were analysed.

Methods

Logistical and linear regressions were used to evaluate relationships between the teasing variables, depression and UWCBs, controlling for age and gender.

Results

Results indicated that children teased by other children have significantly higher levels of depression (B = 6.1 [SE = 2.3]) and are five times more likely to engage in UWCBs (OR = 5.1 [CI = 1.5–17.4]). Children who endorsed that teasing by peers bothered them had significantly higher levels of depression (B = 2.3 [SE = 0.8]). The frequency of weight‐related teasing was significantly associated with depression (B = 2.5 [SE = 0.8]), as was the number of teasing sources (B = 4.6 [SE = 1.5]). No significant relationships were found between familial teasing and depression or UWCBs.

Conclusions

Weight‐related teasing, especially by other children, was associated with negative psychosocial measures in these obese children. Interventions are needed to reduce teasing, and longitudinal studies are recommended to understand the impact of teasing over time.
Comparison of two waist circumference measurement protocols: the SEARCH for diabetes in youth study
Authors: Pettitt D. J. , Talton J. W. , Liese A. D. , Liu L. L. , Crimmins N. , West N. A. , D' Agostino R. B. , Kahn H. S. ,   the SEARCH for Diabetes in Youth Study Group
Published: September 2012

Background

Reports comparing waist circumference (WC) measurements from young populations are scarce.

Objectives

We compared two protocols for measuring waist circumference in a sample of youth with diabetes.

Methods

Participants were enrolled in the SEARCH for Diabetes in Youth Study (SEARCH). WC was measured at least twice by the National Health and Nutrition Examination Survey (NHANES) protocol and twice by the World Health Organization (WHO) protocol. Method‐specific averages were used in these analyses.

Results

Among 6248 participants, the mean NHANES WC (76.3 cm) was greater than the mean WHO WC (71.9 cm). Discrepancies between protocols were greater for females than males, among older participants, and in those with higher body mass index (BMI). In both sexes and four age strata, the WCs using either method were highly correlated with BMI z‐score. The within‐method differences between the first and second measurements were similar for the two methods.

Conclusions

These analyses do not provide evidence that one of these two methods is more reproducible or is a better indicator of obesity as defined by BMI z‐scores.