bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship Between Post‐Thaw Sperm DNA Integrity and Non‐Return Rate Among Norwegian Cross‐Bred Rams
Authors: Nordstoga AB , Krogenæs A , Nødtvedt A , Farstad W , Waterhouse K
Published: August 2012

Contents

With the aim of investigating the relationship between sperm DNA integrity and non‐return rate (NRR) among Norwegian cross‐bred rams, semen from 15 individuals was examined by flow cytometry. Sperm Chromatin Structure Assay (SCSA) quantifies the proportion of spermatozoa with denatured DNA after in situ acid treatment, and the four parameters % DFI, % HDS, MEAN DFI and SD DFI are all different measures of DNA denaturation and maturation. Field fertility, reported as NRR 25 days after insemination was based on all inseminations from a large‐scale breeding programme and supplied by the Norwegian Association of Sheep and Goat Farmers. From each ram, four straws from four different weeks of the breeding season were analysed, and the associations between 25‐day NRR and the mean of the four SCSA parameters were tested using a logistic regression model. The results revealed no association between fertility and % DFI or % HDS, while SD DFI and MEAN DFI showed a significant negative association with NRR. Further, the SCSA values varied significantly between ejaculates within ram among some of the rams in the study. However, no significant association was seen between these intra‐individual differences in sperm DNA integrity and NRR. In conclusion, this study suggests an association between sperm DNA integrity and NRR for rams. However, further research must be conducted to confirm these findings and determine whether sperm DNA assessments can be applied to predict ram fertility.
Cannibalism can drive the evolution of behavioural phase polyphenism in locusts
Authors: Guttal Vishwesha , Romanczuk Pawel , Simpson Stephen J. , Sword Gregory A. , Couzin Iain D.
Published: August 2012

During outbreaks, locust swarms can contain millions of insects travelling thousands of kilometers while devastating vegetation and crops. Such large‐scale spatial organization is preceded locally by a dramatic density‐dependent phenotypic transition in multiple traits. Behaviourally, low‐density ‘solitarious’ individuals avoid contact with one another; above a critical local density, they undergo a rapid behavioural transition to the ‘gregarious phase’ whereby they exhibit mutual attraction. Although proximate causes of this phase polyphenism have been widely studied, the ultimate driving factors remain unclear. Using an individual‐based evolutionary model, we reveal that cannibalism, a striking feature of locust ecology, could lead to the evolution of density‐dependent behavioural phase‐change in juvenile locusts. We show that this behavioural strategy minimizes risk associated with cannibalistic interactions and may account for the empirically observed persistence of locust groups during outbreaks. Our results provide a parsimonious explanation for the evolution of behavioural plasticity in locusts.
Beyond the tradition: test of an integrative conceptual model on nurse turnover
Authors: Battistelli A. , Portoghese I. , Galletta M. , Pohl S.
Published: August 2012

BATTISTELLI A., PORTOGHESE I., GALLETTA M. & POHL S. (2013) Beyond the tradition: test of an integrative conceptual model on nurse turnover. International Nursing Review60, 103–111

Aim:  This paper aimed to extend research on nurse turnover by developing and testing a theoretical model of turnover intention that includes two emergent key off‐the‐job constructs, work–family conflict (WFC) and community embeddedness (CE).

Background:  Nurse turnover is considered one of the most significant issues in health care. There is a considerable body of knowledge that has focused on the study of the on‐the‐job factors of nurse turnover, showing the important role of job attitudes. Recently, WFC and job embeddedness (JE) have been identified as variables that could help explain levels of nurse turnover.

Methods:  Using structural equation modelling from a cross‐sectional survey, the relationships between the variables were explored in a sample of 440 nurses from an Italian public hospital. The questionnaire measures demographic data and psychosocial factors such as job satisfaction, organizational commitment, WFC, CE and turnover intentions.

Results:  The findings supported the importance of non‐work dimensions in turnover models.

Conclusions:  The results suggest that when studying turnover phenomena in health organizations, the extra‐work domains (WFC and JE) can contribute to a decrease in the intention to leave, in addition to the more typically emphasized attitude dimension.
The Strength of Weak States? Non‐State Security Forces and Hybrid Governance in Africa
Authors: Meagher Kate
Published: August 2012

In this article, I explore the recent revalorization of non‐state forms of order and authority in the context of hybrid approaches to governance and state building in Africa. I argue for a more empirical and comparative approach to hybrid governance that is capable of distinguishing between constructive and corrosive forms of non‐state order, and sharpens rather than blurs the relationship between formal and informal regulation. A critique of the theoretical and methodological issues surrounding hybrid governance perspectives sets the scene for a comparative analysis of two contrasting situations of hybrid security systems: the RCD‐ML of eastern DR Congo, and the Bakassi Boys vigilante group of eastern Nigeria. In each case, four issues are examined: the basis of claims that regulatory authority has shifted to informal security systems; the local legitimacy of the security forces involved; the wider political context; and finally, whether a genuine transformation of regulatory authority has resulted, offering local populations a preferable alternative to the prior situation of neglectful or predatory rule. I argue that hybrid governance perspectives often essentialize informal regulatory systems, disguising coercion and political capture as popular legitimacy, and I echo calls for a more historically and empirically informed analysis of hybrid governance contexts.
Developmental changes in the multisensory temporal binding window persist into adolescence
Authors: Hillock‐Dunn Andrea , Wallace Mark T.
Published: August 2012

We live in a world rich in sensory information, and consequently the brain is challenged with deciphering which cues from the various sensory modalities belong together. Determinations regarding the relatedness of sensory information appear to be based, at least in part, on the spatial and temporal relationships between the stimuli. Stimuli that are presented in close spatial and temporal correspondence are more likely to be associated with one another and thus ‘bound’ into a single perceptual entity. While there is a robust literature delineating behavioral changes in perception induced by multisensory stimuli, maturational changes in multisensory processing, particularly in the temporal realm, are poorly understood. The current study examines the developmental progression of multisensory temporal function by analyzing responses on an audiovisual simultaneity judgment task in 6‐ to 23‐year‐old participants. The overarching hypothesis for the study was that multisensory temporal function will mature with increasing age, with the developmental trajectory for this change being the primary point of inquiry. Results indeed reveal an age‐dependent decrease in the size of the ‘multisensory temporal binding window’, the temporal interval within which multisensory stimuli are likely to be perceptually bound, with changes occurring over a surprisingly protracted time course that extends into adolescence.
Voluntary Pension Saving for Old Age: Are the Objectives of Self‐responsibility and Security Compatible?
Authors: Casey Bernard H. , Dostal Jörg Michael
Published: August 2012

Fiscal pressure and demographic change lead governments to seek ways of reducing state expenditure on pensions. Individuals are asked to take more responsibility, and funded, supplementary pension schemes have been established in many countries. This article looks at schemes that are voluntary – the NEST or Personal Accounts scheme in Britain and the Riester Pension scheme in Germany. It examines the debate about whether it is worthwhile for some people to participate in pension schemes that are not mandatory – particularly those with low incomes and/or potentially broken careers. The small pensions they accumulate in such schemes merely offset entitlements to means‐tested pension benefits, leaving them no better off in old age. Concerns about the behavioural consequences of pension means‐testing are not new. Nonetheless, few policymakers have been willing to look at when and how such concerns were expressed in the context of voluntary pension savings. Equally, they have seldom been prepared to explain the costs involved in guaranteeing savings‐based pensions or the implications that the lack of offering such a guarantee might have for individual behaviour. The state has sought for people to take greater ‘self‐responsibility’ for their retirement income, but many people wish for some certainty with respect to the pensions they can expect. These goals might well be in conflict. Whether the ‘state pension for the 21st century’, as proposed by the UK government, will succeed in satisfying the objectives both of the state and of pension savers remains an open question.
Modelling in vivo skeletal muscle ageing in vitro using three‐dimensional bioengineered constructs
Authors: Sharples Adam P. , Player Darren J. , Martin Neil R. W. , Mudera Vivek , Stewart Claire E. , Lewis Mark P.
Published: August 2012

Degeneration of skeletal muscle (SkM) with age (sarcopenia) is a major contributor to functional decline, morbidity and mortality. Methodological implications often make it difficult to embark on interventions in already frail and diseased elderly individuals. Using in vitro three‐dimensional (3D) bioengineered skeletal muscle constructs that model aged phenotypes and incorporate a representative extracellular matrix (collagen), are under tension, and display morphological and transcript expression of mature skeletal muscle may more accurately characterize the SkM niche. Furthermore, an in vitro model would provide greater experimental manipulation with regard to gene, pharmacological and exercise (mechanical stretch/electrical stimulation) therapies and thus strategies for combating muscle wasting with age. The present study utilized multiple population‐doubled (MPD) murine myoblasts compared with parental controls (CON), previously shown to have an aged phenotype in monolayer cultures (Sharples et al., 2011), seeded into 3D type I collagen matrices under uniaxial tension. 3D bioengineered constructs incorporating MPD cells had reduced myotube size and diameter vs. CON constructs. MPD constructs were characterized by reduced peak force development over 24 h after cell seeding, reduced transcript expression of remodelling matrix metalloproteinases, MMP2 and MMP9, with reduced differentiation/hypertrophic potential shown by reduced IGF‐I, IGF‐IR, IGF‐IEa, MGF mRNA. Increased IGFBP2 and myostatin in MPD vs. CON constructs also suggested impaired differentiation/reduced regenerative potential. Overall, 3D bioengineered skeletal muscle constructs represent an in vitro model of the in vivo cell niche with MPD constructs displaying similar characteristics to ageing/atrophied muscle in vivo, thus potentially providing a future test bed for therapeutic interventions to contest muscle degeneration with age.
Understanding the effectiveness of school‐based interventions to prevent suicide: a realist review
Authors: Balaguru Vasumathi , Sharma Juhi , Waheed Waquas
Published: August 2012

Background

Schools appear an obvious place to deliver suicide prevention interventions for children and adolescents. The complexity of suicide interventions lead to a paucity of good quality evidence. An alternate approach of information gathering is needed to identify and collate evidence from existing interventions.

Scope

We completed a realist review of school‐based suicide interventions. This is a novel method of understanding complex interventions that uses an iterative approach. In this review, we attempt to clarify and lay out what type of suicide intervention programme might be useful in schools, based on the local needs and context.

Conclusion

It is possible to develop and implement an evidence‐based suicide intervention in schools by understanding the different processes that can contribute to success or failure of these interventions in a real‐world setting.
Exponential error reduction in pretransfusion testing with automation
Authors: South Susan F. , Casina Tony S. , Li Lily
Published: August 2012

BACKGROUND: Protecting the safety of blood transfusion is the top priority of transfusion service laboratories. Pretransfusion testing is a critical element of the entire transfusion process to enhance vein‐to‐vein safety. Human error associated with manual pretransfusion testing is a cause of transfusion‐related mortality and morbidity and most human errors can be eliminated by automated systems. However, the uptake of automation in transfusion services has been slow and many transfusion service laboratories around the world still use manual blood group and antibody screen (G&S) methods.

STUDY DESIGN AND METHODS: The goal of this study was to compare error potentials of commonly used manual (e.g., tiles and tubes) versus automated (e.g., ID‐GelStation and AutoVue Innova) G&S methods. Routine G&S processes in seven transfusion service laboratories (four with manual and three with automated G&S methods) were analyzed using failure modes and effects analysis to evaluate the corresponding error potentials of each method.

RESULTS: Manual methods contained a higher number of process steps ranging from 22 to 39, while automated G&S methods only contained six to eight steps. Corresponding to the number of the process steps that required human interactions, the risk priority number (RPN) of the manual methods ranged from 5304 to 10,976. In contrast, the RPN of the automated methods was between 129 and 436 and also demonstrated a 90% to 98% reduction of the defect opportunities in routine G&S testing.

CONCLUSION: This study provided quantitative evidence on how automation could transform pretransfusion testing processes by dramatically reducing error potentials and thus would improve the safety of blood transfusion.
A Death Following Hemopericardium Due to Rupture of a Right Ventricular Aneurysm Due to a Congenital Ventricular Septal Defect
Authors: Kodikara Sarathchandra
Published: August 2012

Right ventricular aneurysm (RVA) is a rare clinicopathological entity. Although it occurs as a consequence of a variety of conditions, congenital ventricular septal defect (VSD) as an etiology for the RVA has not been previously reported. A 42‐year‐old man without a significant family or past medical history was found dead in bed. At autopsy, the internal examination revealed a hemopericardium of 280 mL. There was a 1.5 cm diameter ruptured aneurysm of the free wall of the right ventricle. A VSD was present in the lower part of the muscular interventricular septum. The RVA was directly facing to the VSD without any obstruction in between. Microscopically the wall of the aneurysm consisted only of a thin layer of fibrous tissue transmurally with minimal interspersed cardiomyocytes. Cause of death was concluded as hemopericardium following rupture of RVA caused by a congenital VSD.
Relation of fruit color, elongation, hardness, and volume to the infestation of olive cultivars by the olive fruit fly,Bactrocera oleae
Authors: Rizzo Roberto , Caleca Virgilio , Lombardo Alberto
Published: August 2012

The susceptibility of olive cultivars to the olive fruit fly,Bactrocera oleae(Rossi) (Diptera:Tephritidae), has seldom been studied. This article examines factors associated with olive fruit fly infestation of 16 commonly planted Sicilian olive cultivars. Total infestation data were simultaneously correlated with categorical and quantitative factors using ordinal logistic regression. When all factors were included in the analysis, year, sampling date, cultivar, and fruit color were highly significant, but the quantitative factors fruit volume, fruit elongation, and fruit hardness were not. When the analysis was repeated excluding cultivar, all quantitative factors were significant, and elongation and volume were highly significant. Spherical, large, and hard fruit seemed to be preferred byB. oleaeover fruit that are elongate, small, and soft. Therefore, fruit color, elongation, volume, and hardness provide useful information regarding the susceptibility of cultivars. In both organic and conventional olive cultivation, information about olive cultivar susceptibility to olive fruit fly will help orchard managers to produce quality oil and table olives while reducing treatments for olive fruit fly control.
Baboon spermatology: basic assessment and reproducibility in olive baboons (Papio anubis)
Authors: Nyachieo Atunga , Spiessens Carl , Chai Daniel C. , Kiulia Nicholas M. , Mwenda Jason M. , D'Hooghe Thomas M.
Published: August 2012

Background

Development of a reproducible baboon in vitro fertilization (IVF) system require optimized and reproducible sperm parameters. The objective of this study was to document basic spermatology values and investigate the reproducibility of these variables in the same baboons 1 or 3 months later in a larger number of baboons.

Methods

In this prospective study, sperm quality (semen volume, pH, concentration, motility, morphology and size) was evaluated in 27 sperm samples obtained from 9 baboons electroejaculated three times with a time interval of 1 month (between first and second sample collection) and 3 months (between second and third round sample collection).

Results

Baseline sperm values for semen volume (0.5 ± 0.3 ml), pH (7.5 ± 0.3), concentration (54.2 ± 19.3 million/ml), motility (67.3 ± 18.5%) and morphology (89.2 ± 4.8%) were similar to sperm samples obtained after 1 or 3 months (P > 0.05). Head, midpiece and tail abnormalities were rarely observed (0–9%). Sperm dimensions were characterized by a tail length of 69.6 ± 13.9 μm, a head width of 2.41 ± 0.43 μm and a head length of 3.49 ± 0.6 μm.

Conclusion

Sperm quality was not affected by repeated electroejaculation with time intervals of 1 or 3 months, suggesting that the same baboon can participate multiple times in reproductive research.
ApoE isoform‐dependent deficits in extinction of contextual fear conditioning
Authors: Olsen R. H. J. , Agam M. , Davis M. J. , Raber J.
Published: August 2012

The three major human apoE isoforms (apoE2, apoE3 and apoE4) are encoded by distinct alleles (ϵ2, ϵ3 and ϵ4). Compared with ϵ3, ϵ4 is associated with increased risk to develop Alzheimer's disease (AD), cognitive impairments in Parkinson's disease (PD), and other conditions. In contrast, a recent study indicated an increased susceptibility to the recurring and re‐experiencing symptom cluster of Post‐Traumatic Stress Disorder (PTSD), as well as related memory impairments, in patients carrying at least one ϵ2 allele. Contextual fear conditioning and extinction are used in human and animal models to study this symptom cluster. In this study, acquisition (day 1, training), consolidation (day 2, first day of re‐exposure) and extinction (days 2–5) of conditioned contextual fear in human apoE2, apoE3 and apoE4 targeted replacement and C57BL/6J wild‐type (WT) mice was investigated. Male and female apoE2 showed acquisition and retrieval of conditioned fear, but failed to exhibit extinction. In contrast, WT, apoE3 and apoE4 mice showed extinction. While apoE2 mice exhibited lower freezing in response to the context on day 2 than apoE3 and apoE4 mice, this cannot explain their extinction deficit as WT mice exhibited similar freezing levels as apoE2 mice on day 2 but still exhibited extinction. Elevating freezing through extended training preserved extinction in controls, but failed to ameliorate extinction deficits in apoE2 animals. These data along with clinical data showing an association of apoE2 with susceptibility to specific symptom clusters in PTSD supports an important role for apoE isoform in the extinction of conditioned fear.
A Statistical Journey to the Centre of the Earth
Authors: Ma Ping
Published: August 2012

What lies beneath our feet? Huge quantities of data and complex analysis have revealed an Earth that is spinning at its core, says Ping Ma.
Viability of small seeds found in feces of the Central American tapir on Barro Colorado Island, Panama
Authors: CAPECE Paula I. , ALIAGA‐ROSSEL Enzo , JANSEN Patrick A.
Published: August 2012

Tapirs are known as effective dispersers of large‐seeded tree species, but their role in dispersing small‐seeded plant species has yet to be established. Tapir feces have been reported to contain large numbers of small seeds, but whether these are viable has rarely been evaluated. We determined the abundance and viability of small seeds in feces of Central American tapir (Tapirus bairdii) on Barro Colorado Island, Panama. A total of 72 fecal samples were collected opportunistically from 4 tapir latrine sites. Seeds were manually extracted from feces and classified by size. Seed viability was estimated by opening each seed and examining for the presence of at least 1 intact firm white endosperm. In total, we obtained 8166 seeds of at least 16 plant species. Small‐seeded species dominated, with 96% of all seeds found measuring <5 mm. The canopy tree Laetia procera was the most abundant species in the samples. Of all small seeds found, 69% contained an intact endosperm and appeared viable. This suggests that small seeds, like large seeds, often pass through the digestive tract of T. bairdii intact. Thus, tapirs potentially serve as effective dispersers of a wide range of small‐seeded plant species.
Dilemmas in Treating Hypertension in Octogenarians
Authors: Tabriziani Hossein , Steiner Jill , Papademetriou Vasilious
Published: August 2012

J Clin Hypertens (Greenwich). 2012;14:711–717. ©2012 Wiley Periodicals, Inc.

One quarter of Americans will be older than 80 by 2030, and hypertension in this group will be ubiquitous. Most studies of hypertension exclude octogenarians and are not able to be generalized because of differences in physiologic and social phenomena. This review evaluates the existing literature in an effort to identify unresolved issues and guide future areas of investigation. Hypertension has been well characterized in adults and the young elderly, and the focus is on optimizing treatment regimens. However, research specifically involving this rapidly growing minority is sparse. Most studies are still trying to characterize blood pressure goals, and only one major series has begun to evaluate treatment options. Based on available evidence, it appears that an appropriate blood pressure goal may be somewhat higher in octogenarians and that thiazide diuretics may be the initial treatment of choice.
Patterns of dental service utilization following nontraumatic dental condition visits to the emergency department in Wisconsin Medicaid
Authors: Pajewski Nicholas M. , Okunseri Christopher
Published: August 2012

Objectives: To examine patterns of dental service utilization for adult Medicaid enrollees in Wisconsin following nontraumatic dental condition (NTDC) visits to the emergency department (ED).

Methods: This is a retrospective, observational study of claims for NTDC visits to the ED and dental service encounters from the Wisconsin Medicaid Evaluation and Decision Support database (2001‐2009). We used competing risk models to predict probabilities of returning to the ED versus obtaining follow‐up care from a dentist.

Results: We observed a 43 percent increase in the rate of NTDC visits to the ED, with most of this increase occurring from 2001 to 2005. Within 30 days of an NTDC visit to the ED, ∼29.6 percent of enrollees will first visit a dentist office, while ∼9.9 percent will return to the ED. Young to middle‐aged adults (18 to <50 years) and enrollees living in counties with a lower supply of dental providers were more likely to return to the ED following a NTDC visit. Among the enrollees that first visited a dental office following an ED visit, 37.6 percent had an extraction performed at this visit.

Conclusions: Almost one in five adult Medicaid enrollees will subsequently return to the ED following a previous NTDC visit. The provision of definitive care for these individuals appears to primarily consist of extractions.
Very low and low birth weight associated with maternal periodontitis
Authors: Guimarães Alessandra N. , Silva‐Mato Agustín , Siqueira Fernanda M. , Cyrino Renata M. , Cota Luís O. M. , Costa Fernando O.
Published: August 2012

Aim

The aim of this study was to evaluate the association of very low and low birth weight (VLBWandLBW) with maternal periodontitis.

Material and Methods

Overall, 1206 women were examined at post‐partum and two alternative criteria for periodontitis definition were used: (1) four or more teeth with at least one site with probing depth (PD) ≥4 mm and clinical attachment loss (CAL) ≥3 mm; and (2) at least one site withPDandCAL≥4 mm. For each definition, two multivariate analyses were performed: (1) linear regression for birth weight; (2) ordinal logistic regression for birth weight, categorized as adequate (n = 1046),LBW(n = 145) andVLBW(n = 15).

Results

Linear regression showed that maternal periodontitis was associated with a decrease in mean birth weight (periodontitis definition 1:p = 0.027; periodontitis definition 2:p = 0.003). Ordinal logistic regression showed that maternal periodontitis was associated withLBWandVLBW[odds ratio (OR) = 2.0; 95% confidence interval (CI) 1.39–2.90, when considering periodontitis definition 2]; and withLBW(OR = 1.65; 95%CI1.15–2.36, when considering periodontitis definition 1).

Conclusion

Maternal periodontitis was associated with a decrease in mean birth weight, as well as withLBWandVLBW.
Melanocortin 3/4 receptors in paraventricular nucleus modulate sympathetic outflow and blood pressure
Authors: Li Peng , Cui Bai‐Ping , Zhang Ling‐Li , Sun Hai‐Jian , Liu Tong‐Yan , Zhu Guo‐Qing
Published: August 2012

New findings

What is the central question of this study?

The paraventricular nucleus (PVN) is important in regulating sympathetic activity and blood pressure. This study addresses whether activation of melanocortin 3/4 receptors in the PVN modulates sympathetic activity and blood pressure, and whether intracellular signalling involves the cAMP–protein kinase A pathway.

What is the main finding and its importance?

Activation of melanocortin 3/4 receptors in the PVN increases sympathetic outflow and blood pressure via the cAMP–protein kinase A pathway. Melanocortin 3 receptors in the PVN exert a tonic excitatory effect on sympathetic activity. Melanocortin 3/4 receptors in the PVN are a putative therapeutic target to inhibit sympathetic activity.

Central melanocortin 3/4 receptors (MC3/4Rs) are known to regulate energy balance. Activation of MC3/4Rs causes a greater increase in the firing activity of the PVN neurons in obese Zucker rats than in lean Zucker rats. The present study was undertaken to determine the roles of MC3/4Rs in the hypothalamic paraventricular nucleus (PVN) in modulating the sympathetic activity and blood pressure and its downstream pathway. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in anaesthetized rats. Microinjection of the MC3/4R agonist melanotan II (MTII) into the PVN increased the RSNA and MAP. The MC3/4R antagonist agouti‐related peptide (AgRP) or SHU9119 decreased the RSNA and MAP, but the MC4R antagonist HS024 had no significant effect on the RSNA and MAP. The effects of MTII were abolished by pretreatment of the PVN with AgRP, SHU9119, the adenylate cyclase inhibitor SQ22536 or the protein kinase A inhibitor Rp‐cAMP, and substantially attenuated by HS024. Microinjection of SQ22536 alone into the PVN had no significant effect on the RSNA and MAP, but Rp‐cAMP caused significant decreases in the RSNA and MAP. Furthermore, MTII increased the cAMP level in the PVN. These results indicate that activation of MC3/4Rs in the PVN increases the sympathetic outflow and blood pressure via the cAMP–protein kinase A pathway. Melanocortin 3 receptors in the PVN may exert a tonic excitatory effect on sympathetic activity.
Scattering from extended targets in range-dependent fluctuating ocean-waveguides with clutter from theory and experiments
Authors: Jagannathan Srinivasan , Küsel Elizabeth T. , Ratilal Purnima , Makris Nicholas C.
Published: August 2012

Bistatic, long-range measurements of acoustic scattered returns from vertically extended, air-filled tubular targets were made during three distinct field experiments in fluctuating continental shelf waveguides. It is shown that Sonar Equation estimates of mean target-scattered intensity lead to large errors, differing by an order of magnitude from both the measurements and waveguide scattering theory. The use of the Ingenito scattering model is also shown to lead to significant errors in estimating mean target-scattered intensity in the field experiments because they were conducted in range-dependent ocean environments with large variations in sound speed structure over the depth of the targets, scenarios that violate basic assumptions of the Ingenito model. Green’s theorem based full-field modeling that describes scattering from vertically extended tubular targets in range-dependent ocean waveguides by taking into account nonuniform sound speed structure over the target’s depth extent is shown to accurately describe the statistics of the targets’ scattered field in all three field experiments. Returns from the man-made targets are also shown to have a very different spectral dependence from the natural target-like clutter of the dominant fish schools observed, suggesting that judicious multi-frequency sensing may often provide a useful means of distinguishing fish from man-made targets.
Adapting to suprasegmental lexical stress errors in foreign-accented speech
Authors: Reinisch Eva , Weber Andrea
Published: August 2012

Can native listeners rapidly adapt to suprasegmental mispronunciations in foreign-accented speech? To address this question, an exposure-test paradigm was used to test whether Dutch listeners can improve their understanding of non-canonical lexical stress in Hungarian-accented Dutch. During exposure, one group of listeners heard a Dutch story with only initially stressed words, whereas another group also heard 28 words with canonical second-syllable stress (e.g., EEKhorn, “squirrel” was replaced by koNIJN “rabbit”; capitals indicate stress). The 28 words, however, were non-canonically marked by the Hungarian speaker with high pitch and amplitude on the initial syllable, both of which are stress cues in Dutch. After exposure, listeners’ eye movements were tracked to Dutch target-competitor pairs with segmental overlap but different stress patterns, while they listened to new words from the same Hungarian speaker (e.g., HERsens, herSTEL, “brain,” “recovery”). Listeners who had previously heard non-canonically produced words distinguished target-competitor pairs better than listeners who had only been exposed to Hungarian accent with canonical forms of lexical stress. Even a short exposure thus allows listeners to tune into speaker-specific realizations of words’ suprasegmental make-up, and use this information for word recognition.
Dolphin biosonar signals measured at extreme off-axis angles: Insights to sound propagation in the head
Authors: Au Whitlow W. L. , Branstetter Brian , Moore Patrick W. , Finneran James J.
Published: August 2012

Biosonar signals radiated along the beam axis of an Atlantic bottlenose dolphin resemble short transient oscillations. As the azimuth of the measuring hydrophones in the horizontal plane progressively increases with respect to the beam axis the signals become progressively distorted. At approximately ±45°, the signals begin to divide into two components with the time difference between the components increasing with increasing angles. At ±90° or normal to the longitudinal axis of the animal, the time difference between the two pulses measured by the hydrophone on the right side of the dolphin’s head is, on average, ∼11.9 μs larger than the time differences observed by the hydrophone on the left side of the dolphin’s head. The center frequency of the first pulse is generally lower, by 33–47 kHz, than the center frequency of the second pulse. When considering the relative locations of the two phonic lips, the data suggest that the signals are being produced by one of the phonic lips and the second pulse resulting from a reflection within the head of the animal. The generation of biosonar signals is a complex process and the propagation pathways through the dolphin’s head are not well understood.
Anisotropy in high-frequency broadband acoustic backscattering in the presence of turbulent microstructure and zooplankton
Authors: Leong Doris , Ross Tetjana , Lavery Andone
Published: August 2012

High-frequency broadband (120–600 kHz) acoustic backscattering measurements have been made in the vicinity of energetic internal waves. The transducers on the backscattering system could be adjusted so as to insonify the water-column either vertically or horizontally. The broadband capabilities of the system allowed spectral classification of the backscattering. The distribution of spectral shapes is significantly different for scattering measurements made with the transducers oriented horizontally versus vertically, indicating that scattering anisotropy is present. However, the scattering anisotropy could not be unequivocally explained by either turbulent microstructure or zooplankton, the two primary sources of scattering expected in internal waves. Daytime net samples indicate a predominance of short-aspect-ratio zooplankton. Using zooplankton acoustic scattering models, a preferential orientation of the observed zooplankton cannot explain the measured anisotropy. Yet model predictions of scattering from anisotropic turbulent microstructure, with inputs from coincident microstructure measurements, were not consistent with the observations. Possible explanations include bandwidth limitations that result in many spectra that cannot be unambiguously attributed to turbulence or zooplankton based on spectral shape. Extending the acoustic bandwidth to cover the range from 50 kHz to 2 MHz could help improve identification of the dominant sources of backscattering anisotropy.
Use of a compound approach to derive auditory-filter-wide frequency-importance functions for vowels and consonants
Authors: Apoux Frédéric , Healy Eric W.
Published: August 2012

Speech recognition in noise presumably relies on the number and spectral location of available auditory-filter outputs containing a relatively undistorted view of local target signal properties. The purpose of the present study was to estimate the relative weight of each of the 30 auditory-filter wide bands between 80 and 7563 Hz. Because previous approaches were not compatible with this goal, a technique was developed. Similar to the “hole” approach, the weight of a given band was assessed by comparing intelligibility in two conditions differing in only one aspect—the presence or absence of the band of interest. In contrast to the hole approach, however, random gaps were also created in the spectrum. These gaps were introduced to render the auditory system more sensitive to the removal of a single band and their location was randomized to provide a general view of the weight of each band, i.e., irrespective of the location of information elsewhere in the spectrum. Frequency-weighting functions derived using this technique confirmed the main contribution of the 400–2500 Hz frequency region. However, they revealed a complex microstructure, contrasting with the “bell curve” shape typically reported.
Musical background not associated with self-perceived hearing performance or speech perception in postlingual cochlear-implant users
Authors: Fuller Christina , Free Rolien , Maat Bert , Başkent Deniz
Published: August 2012

In normal-hearing listeners, musical background has been observed to change the sound representation in the auditory system and produce enhanced performance in some speech perception tests. Based on these observations, it has been hypothesized that musical background can influence sound and speech perception, and as an extension also the quality of life, by cochlear-implant users. To test this hypothesis, this study explored musical background [using the Dutch Musical Background Questionnaire (DMBQ)], and self-perceived sound and speech perception and quality of life [using the Nijmegen Cochlear Implant Questionnaire (NCIQ) and the Speech Spatial and Qualities of Hearing Scale (SSQ)] in 98 postlingually deafened adult cochlear-implant recipients. In addition to self-perceived measures, speech perception scores (percentage of phonemes recognized in words presented in quiet) were obtained from patient records. The self-perceived hearing performance was associated with the objective speech perception. Forty-one respondents (44% of 94 respondents) indicated some form of formal musical training. Fifteen respondents (18% of 83 respondents) judged themselves as having musical training, experience, and knowledge. No association was observed between musical background (quantified by DMBQ), and self-perceived hearing-related performance or quality of life (quantified by NCIQ and SSQ), or speech perception in quiet.
Correction of tissue-motion effects on common-midpoint signals using reciprocal signals
Authors: Li Yue , Robinson Brent
Published: August 2012

The near field signal redundancy algorithm for phase-aberration correction is sensitive to tissue motion because several separated transmissions are usually needed to acquire a set of common-midpoint signals. If tissues are moving significantly due to, for example, heart beats, the effects of tissue motion on common-midpoint signals need to be corrected before the phase-aberration profile can be successfully measured. Theoretical analyses in this paper show that the arrival-time difference between a pair of common-midpoint signals due to tissue motion is usually very similar to that between the pair of reciprocal signals acquired using the same two transmissions. Based on this conclusion, an algorithm for correcting tissue-motion effects on the peak position of cross-correlation functions between common-midpoint signals is proposed and initial experimental results are also presented.
Comparing behavioral and physiological measures of combination tones: Sex and race differences
Authors: McFadden Dennis , Pasanen Edward G. , Leshikar Erin M. , Hsieh Michelle D. , Maloney Mindy M.
Published: August 2012

Both distortion-product otoacoustic emissions (DPOAEs) and performance in an auditory-masking task involving combination tones were measured in the same frequency region in the same ears. In the behavioral task, a signal of 3.6 kHz (duration 300 ms, rise/fall time 20 ms) was masked by a 3.0-kHz tone (62 dB SPL, continuously presented). These two frequencies can produce a combination tone at 2.4 kHz. When a narrowband noise (2.0–2.8 kHz, 17 dB spectrum level) was added as a second masker, detection of the 3.6-kHz signal worsened by 6–9 dB (the Greenwood effect), revealing that listeners had been using the combination tone at 2.4 kHz as a cue for detection at 3.6 kHz. Several outcomes differed markedly by sex and racial background. The Greenwood effect was substantially larger in females than in males, but only for the White group. When the magnitude of the Greenwood effect was compared with the magnitude of the DPOAE measured in the 2.4 kHz region, the correlations typically were modest, but were high for Non-White males. For many subjects, then, most of the DPOAE measured in the ear canal apparently is not related to the combination-tone cue that is masked by the narrowband noise.
Water Sustainability for China and Beyond
Authors: Liu Jianguo , Yang Wu
Published: August 2012

Despite investments in water infrastructure, China must address complex human-nature interactions to ensure supply and quality.
Evolution of Ocean Temperature and Ice Volume Through the Mid-Pleistocene Climate Transition
Authors: Elderfield H. , Ferretti P. , Greaves M. , Crowhurst S. , McCave I. N. , Hodell D. , Piotrowski A. M.
Published: August 2012

Cycling Down

The Mid-Pleistocene Transition, which lasted from approximately 1.25 million to 700 thousand years ago, was a period during which the dominant periodicity of Earth's climate cycles inexplicably changed from 41 thousand to 100 thousand years. This change is clearly apparent in the oxygen isotopic composition of many calcifying marine organisms, but changes in both ice volume and temperature affect the signal, and so exactly what the signal means has remained unclear.

Elderfield
et al.

(p.
704
; see the Perspective by

Clark

) separated these two effects by measuring both the oxygen isotopic makeup and the Mg/Ca (a proxy that reflects changes in temperature only) of certain benthic foraminifera. The findings reveal the contributions of ice volume and temperature to glacial cycles, suggest when and why the Mid-Pleistocene Climate Transition occurred, and clarify how carbon is lost from the ocean-atmosphere during deglaciations but also changes because of ocean circulation.
Divergent Nematic Susceptibility in an Iron Arsenide Superconductor
Authors: Chu Jiun-Haw , Kuo Hsueh-Hui , Analytis James G. , Fisher Ian R.
Published: August 2012

Lattice Trailing the Electrons

Superconducting order recedes with decreased chemical doping in a typical iron-based superconductor family. Thus, the symmetry of the material is broken by almost simultaneous antiferromagnetic and structural phase transitions. However, some pnictides also exhibit an electronic nematic transition manifested by anisotropy of the electrical resistance. Because this anisotropy occurs at the same time as the structural transition, it is not clear whether it is a consequence of the broken crystal lattice symmetry or its cause.

Chu
et al.

(p.
710
) performed constant strain experiments on the series Ba(Fe
1−x
Co
x
)
2
As
2
, which can distinguish between the two scenarios, and confirm that the electrons drive the lattice transition.
The Challenges of Reusing Mining and Mineral-Processing Wastes
Authors: Bian Zhengfu , Miao Xiexing , Lei Shaogang , Chen Shen-en , Wang Wenfeng , Struthers Sue
Published: August 2012

Mining and mineral-processing wastes are one of the world’s largest chronic waste concerns. Their reuse should be included in future sustainable development plans, but the potential impacts on a number of environmental processes are highly variable and must be thoroughly assessed. The chemical composition and geotechnical properties of the source rock determine which uses are most appropriate and whether reuse is economically feasible. If properly evaluated, mining waste can be reused to reextract minerals, provide additional fuel for power plants, supply construction materials, and repair surface and subsurface land structures altered by mining activities themselves.
Uncovering the Uranium-Nitrogen Triple Bond
Authors: Sattelberger Alfred P. , Johnson Marc J. A.
Published: August 2012

A triple bond formed between a high-valent uranium atom and a nitrogen atom has appreciable f orbital character.
A Henipavirus Vaccine in Sight
Authors: von Messling Veronika , Cattaneo Roberto
Published: August 2012

A candidate vaccine against Nipah and Hendra viruses, recently emerging zoonotic threats, looks promising.
Are World Oil's Prospects Not Declining All That Fast?
Authors: Kerr Richard A.
Published: August 2012

A new report's upbeat message about growing abundance derived via more capable oil-extraction technology depends on more than confidence in that fancy—and expensive—new technology.
The Scientific Approach to Better Birthday Parties
Authors: Obhrai Jagdeep S.
Published: August 2012

Oral immunotherapy creates functional tolerance for patients with food allergy.
Mice May Not Be Liars After All
Authors: Oviedo-Orta Ernesto
Published: August 2012

Similarities found between a newly discovered type of dendritic cell in human and mouse bring new hopes to translational research and drug discovery development.
The Pre-NH
2
-Terminal Domain of the Herpes Simplex Virus 1 DNA Polymerase Catalytic Subunit Is Required for Efficient Viral Replication
Authors: Terrell Shariya L. , Coen Donald M.
Published: August 2012

The catalytic subunit of herpes simplex virus 1 DNA polymerase (HSV-1 Pol) has been extensively studied; however, its full complement of functional domains has yet to be characterized. A crystal structure has revealed a previously uncharacterized pre-NH
2
-terminal domain (residues 1 to 140) within HSV-1 Pol. Due to the conservation of the pre-NH
2
-terminal domain within the herpesvirus Pol family and its location in the crystal structure, we hypothesized that this domain provides an important function during viral replication in the infected cell distinct from 5′-3′ polymerase activity. We identified three pre-NH
2
-terminal Pol mutants that exhibited 5′-3′ polymerase activity indistinguishable from that of wild-type Pol
in vitro
: deletion mutants PolΔN43 and PolΔN52 that lack the extreme N-terminal 42 and 51 residues, respectively, and mutant PolA
6
, in which a conserved motif at residues 44 to 49 was replaced with alanines. We constructed the corresponding
pol
mutant viruses and found that the
pol
ΔN43 mutant displayed replication kinetics similar to those of wild-type virus, while
pol
ΔN52 and
pol
A
6
mutant virus infection resulted in an 8-fold defect in viral yield compared to that achieved with wild type and their respective rescued derivative viruses. Additionally, both
pol
ΔN52 and
pol
A
6
viruses exhibited defects in viral DNA synthesis that correlated with the observed reduction in viral yield. These results strongly indicate that the conserved motif within the pre-NH
2
-terminal domain is important for viral DNA synthesis and production of infectious virus and indicate a functional role for this domain.
Visualizing Production of Beta Interferon by Astrocytes and Microglia in Brain of La Crosse Virus-Infected Mice
Authors: Kallfass Carsten , Ackerman Andreas , Lienenklaus Stefan , Weiss Siegfried , Heimrich Bernd , Staeheli Peter
Published: August 2012

Beta interferon (IFN-β) is a major component of innate immunity in mammals, but information on the
in vivo
source of this cytokine after pathogen infection is still scarce. To identify the cell types responsible for IFN-β production during viral encephalitis, we used reporter mice that express firefly luciferase under the control of the IFN-β promoter and stained organ sections with luciferase-specific antibodies. Numerous luciferase-positive cells were detected in regions of La Crosse virus (LACV)-infected mouse brains that contained many infected cells. Double-staining experiments with cell-type-specific markers revealed that similar numbers of astrocytes and microglia of infected brains were luciferase positive, whereas virus-infected neurons rarely contained detectable levels of luciferase. Interestingly, if a mutant LACV unable of synthesizing the IFN-antagonistic factor NSs was used for challenge, the vast majority of the IFN-β-producing cells in infected brains were astrocytes rather than microglia. Similar conclusions were reached in a second series of experiments in which conditional reporter mice expressing the luciferase reporter gene solely in defined cell types were infected with wild-type or mutant LACV. Collectively, our data suggest that glial cells rather than infected neurons represent the major source of IFN-β in LACV-infected mouse brains. They further indicate that IFN-β synthesis in astrocytes and microglia is differentially affected by the viral IFN antagonist, presumably due to differences in LACV susceptibility of these two cell types.