bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal Intraspeech Masking of Plosive Bursts: Effects of Hearing Loss and Frequency Shaping
Authors: Mackersie Carol L. 
Published: May 2007

Purpose
The purposes were (a) to compare masking of consonant bursts by adjacent vowels for listeners with and without hearing loss and (b) to determine the extent to which the temporal intraspeech masking can be reduced by a simulated hearing-aid frequency-response shaping.

Method
Fourteen adults with sensorineural hearing loss and 10 with normal hearing participated. Seven of the participants with hearing loss had flat or gradually sloping audiograms, and 7 had steeply sloping losses. Stimuli consisted of 3 consonant bursts (/t/, /p/, /k/) presented in isolation and in vowel-consonant-vowel combinations using the vowel /a/ with formant transition information removed. Normal-hearing listeners were tested using unfiltered stimuli. Listeners with hearing loss were tested using unfiltered stimuli and stimuli filtered to approximate a hearing aid frequency response prescribed by NAL-R. All listeners were tested under earphones at the most comfortable level for the vowel stimulus. Temporal intraspeech masking was quantified as the threshold shift produced by the adjacent vowels.

Results
Average intraspeech masking for listeners with steeply sloping hearing loss was significantly higher than that of normal-hearing listeners and those with flat/gradually sloping losses. Greater intraspeech masking was observed for /t/ and /p/ than for /k/. On average, frequency shaping significantly reduced the amount of intraspeech masking for listeners with steeply sloping hearing losses. Even with appropriate amplification/spectral shaping, however, temporal intraspeech masking remained greater than normal for several individuals.

Conclusion
Findings suggest that some individuals with steeply sloping losses may need additional signal processing to supplement frequency shaping to overcome the effect of temporal intraspeech masking.
Effects of Cueing in Auditory Temporal Masking
Authors: Zhang Ting , Formby Craig 
Published: May 2007

Purpose
In a landmark study, B. A. Wright et al. (1997) reported an apparent backward-masking deficit in language-learning-impaired children. Subsequently, the controversial interpretation of those results has been influential in guiding treatments for childhood language problems. This study revisited the temporal-masking paradigm reported by B. A. Wright et al. to evaluate adult listener signal/masker uncertainty effects for some of their key stimulus conditions. New signal conditions presented off frequency from the masker also were evaluated to assess conditions of reduced signal/masker confusion.

Method
Masked detection was measured for 20-ms sinusoids (480, 1000, or 1680 Hz) presented at temporal positions before, during, or after a gated narrowband (bandwidth = 600–1400 Hz) masker. Listener uncertainty was investigated by cueing various stimulus temporal properties with a 6000-Hz sinusoid presented contralateral to the test ear.

Results
The primary cueing effect was measured in the backward-masking condition for the cue gated simultaneously with the on-frequency 1000-Hz signal. The resulting cued masked-detection threshold was reduced to quiet threshold. No significant cueing effects were obtained for other signal temporal positions in the masker or for any off-frequency signal conditions.

Conclusions
These results for normal adult listeners indicate that on-frequency backward masking can be eliminated by cueing the signal, and thus, these findings raise the possibility that the deficit reported by B. A. Wright et al. for language-learning-impaired children may reflect inordinate signal/masker confusion, rather than a temporal-processing deficit per se.
Basic Auditory Processing Skills and Specific Language Impairment: A New Look at an Old Hypothesis
Authors: Corriveau Kathleen , Pasquini Elizabeth , Goswami Usha 
Published: May 2007

Purpose
To explore the sensitivity of children with specific language impairment (SLI) to amplitude-modulated and durational cues that are important for perceiving suprasegmental speech rhythm and stress patterns.

Method
Sixty-three children between 7 and 11 years of age were tested, 21 of whom had a diagnosis of SLI, 21 of whom were matched for chronological age to the SLI sample, and 21 of whom were matched for language age to the SLI sample. All children received a battery of nonspeech auditory processing tasks along with standardized measures of phonology and language.

Results
As many as 70%–80% of children diagnosed with SLI were found to perform below the 5th percentile of age-matched controls in auditory processing tasks measuring sensitivity to amplitude envelope rise time and sound duration. Furthermore, individual differences in sensitivity to these cues predicted unique variance in language and literacy attainment, even when age, nonverbal IQ, and task-related (attentional) factors were controlled.

Conclusion
Many children with SLI have auditory processing difficulties, but for most children, these are not specific to brief, rapidly successive acoustic cues. Instead, sensitivity to durational and amplitude envelope cues appear to predict language and literacy outcomes more strongly. This finding now requires replication and exploration in languages other than English.
Fast Mapping Skills in the Developing Lexicon
Authors: Gershkoff-Stowe Lisa , Hahn Erin R. 
Published: May 2007

PurposeThis preliminary investigation was a longitudinal study of fast mapping skills in normally developing children, 16–18 months of age. The purpose was to examine the effects of practice on the accessibility of words in lexical memory.MethodEight children were taught the names of 24 unfamiliar objects over 12 weekly training sessions. The amount of practice children had with individual words varied as a function of session. Data were compared to a control group of children—matched on productive vocabulary—who were exposed to the same experimental words at the first and last sessions only.ResultsThe results showed that for children in the experimental group, extended practice with a novel set of high-practice words led to the rapid acquisition of a second set of low-practice words. Children in the control group did not show the same lexical advantage.ConclusionsThe data suggest that learning some words primes the system to learn more words. Vocabulary development can thus be conceptualized as a continual process of fine-tuning the lexical system to enable increased accessibility to information. Implications for the treatment of children with word-finding difficulties are considered.
Velocity model updating in prestack Kirchhoff time migration for PS converted waves: Part II – Application
Authors: Dai Hengchang , Li Xiang‐Yang 
Published: May 2007

ABSTRACTWe have developed a practical approach for updating the velocity of PS converted waves based on the inverse normal‐moveout common‐image‐point gather obtained from prestack Kirchhoff time migration. We have integrated all the steps involved in updating the migration velocity model into an interactive tool and have applied this approach to a real seismic data set from the Alba Field in the North Sea. Based on experience in handling the real data, we discuss various practical aspects of updating the velocity model, including: what kind of initial velocity model should be used; which parameters in the velocity model should be updated; and how to update them. Application of prestack Kirchhoff time migration to the data set using the updated velocity model produces an improved image of the Alba Field.
Tropical montane forest ecotones: climate gradients, natural disturbance, and vegetation zonation in the Cordillera Central, Dominican Republic
Authors: Martin Patrick H. , Sherman Ruth E. , Fahey Timothy J. 
Published: May 2007

AbstractAim We examined relationships between climate–disturbance gradients and patterns of vegetation zonation and ecotones on a subtropical mountain range.Location The study was conducted on the windward slopes of the Cordillera Central, Dominican Republic, where cloud forest appears to shift in a narrow ecotone to monodominant forest ofPinus occidentalis.Methods Climate, disturbance and vegetation data were collected over the elevation range 1100–3100 m and in 50 paired plots along the ecotone. Aerial photographs were georeferenced to a high‐resolution digital elevation model in order to enable the analysis of landscape‐scale patterns of the ecotone.Results A Shipley–Keddy test detected discrete compositional ecotones at 2200 and 2500 m; the distributions of tree species at lower elevations were continuous. The elevation of the ecotone determined with aerial photographs was fairly consistent, namely ± 164 m (SD) over its 124‐km length, but it exhibited significant landscape variation, occurring at a lower elevation in a partially leeward, western zone. The ecotone also occurred significantly lower on ridges than it did in drainage gullies. Ecotone forest structure and composition differed markedly between paired plots. In pine paired plots, the canopy height was 1.7 times higher and the basal area of non‐pine species was 6 times lower than in the cloud forest directly below. Fire evidence was ubiquitous in the pine forest but rare in the abutting cloud forest. Mesoclimate changed discontinuously around the elevation of the ecotone: humidity and cloud formation decreased markedly, and frost frequency increased exponentially.Main conclusions The discreteness of the ecotone was produced primarily by fire. The elevational consistency of the ecotone, however, resulted from the overarching influence of mesoclimate on the elevational patterns of fire occurrence. Declining temperature and precipitation combine with the trade‐wind inversion to create a narrow zone where high‐elevation fires extinguish, enabling fire‐sensitive and fire‐tolerant taxa to abut. Once established, mesotopography and contrasting vegetation physiognomy probably reinforce this boundary through feedbacks on microenvironment and fire likelihood. The prominence of the pine in this study – and of temperate and fire‐tolerant taxa in subtropical montane forests in general – highlights the importance of climate‐disturbance–biogeography interactions in ecotone formation, particularly where fire mediates a dynamic between climate and vegetation.
Prevalence of depression among adults in Oyo State, Nigeria: A comparative study of rural and urban communities
Authors: Amoran Olorunfemi , Lawoyin Taiwo , Lasebikan Victor 
Published: May 2007

AbstractObjective:  This study was designed to assess the current prevalence of depression in Oyo State, Nigeria and the rural–urban variation in prevalence. Setting:  This is a two‐phase community‐based cross‐sectional study. The urban areas selected for the study are the Ibadan North‐West and Egbeda local government areas. The rural area selected was the Saki‐East local government area. Participants:  A total of 1105 participants were recruited into the study. Multistage sampling technique was used to obtain a representative sample of the participants from the communities in Oyo State. The study was conducted using an interviewer‐administered structured questionnaire, and the general health questionnaire (GHQ 12) as a screening tool. The second phase of the interview was conducted only for those participants with a score of more than 3 using the GHQ 12. These participants were then clinically examined using the Structured Clinical Interview DSM IV for assessment of clinical depression. Main outcome measure:  Prevalence of depression. Results:  A total of 721 (65.2%) were from urban communities, while 384 (34.8%) were from the rural community. The overall prevalence of depression was found to be 5.2%. Depression was more prevalent among women than men (5.7% vs 4.8%, χ

2
= 0.36 P = 0.55), and among adolescents (9.6%, P = 0.04). Furthermore, depression was more common in the rural areas than in the urban areas (7.3% vs 4.2%, χ2 = 4.94 P = 0.02).Conclusion:  Depression is more common in rural than urban areas in the Nigerian population. Mental health education for adolescents and secondary school students should be encouraged in rural communities.
Regulation of hepatocyte apoptosis by oxidative stress
Authors: Singh Rajat , Czaja Mark J 
Published: May 2007

AbstractOxidative stress has been implicated as the mechanism of hepatocyte injury from numerous agents. Although reactive oxygen species injure cells by the modification of critical cellular macromolecules, recent studies have demonstrated the mechanistic involvement of oxidant stress‐induced alterations in signal transduction cascades. Studies in menadione‐treated hepatocytes have demonstrated differential effects of mitogen‐activated protein kinase activation on hepatocyte death from acute oxidative stress. Activation of the extracellular signal‐regulated kinase pathway 1/2 (ERK1/2) confers hepatocyte resistance to death whereas sustained c‐Jun N‐terminal kinase (JNK)/c‐Jun/AP‐1 activation promotes apoptosis. Redundant protective signals such as the protein kinase C/protein kinase D pathways also downregulate the JNK/c‐Jun/AP‐1 cascade and provide resistance to cell death. Although ERK1/2 overactivation also acts as a protective response to chronic oxidative stress, enhanced activation of this kinase sensitizes hepatocytes to death from free fatty acids in this setting. The outcome from challenge with an oxidative stress, therefore, depends on the integration of a series of signaling cascades that both protect against and promote hepatocyte apoptosis.
Regulation of macrophage activation in alcoholic liver disease
Authors: Thakur Varsha , McMullen Megan R , Pritchard Michele T , Nagy Laura E 
Published: May 2007

AbstractChronic ethanol feeding sensitizes Kupffer cells to activation by lipopolysaccharide (LPS), leading to increased production of tumor necrosis factor α (TNFα). The regulation of TNFα synthesis is controlled by both transcriptional and post‐transcriptional mechanisms via the integration of complex signal transduction pathways activated in response to LPS exposure. Recent data has shown that increased LPS‐stimulated phosphorylation of extracellular signal‐regulated kinase pathway 1/2 (ERK1/2) is one of the important molecular targets of chronic ethanol in Kupffer cells. This increased activation of ERK1/2 after chronic ethanol is associated with increased expression of Egr‐1, a transcription factor required for enhanced LPS‐stimulated TNFα mRNA expression after chronic ethanol exposure. egr‐1 null mice are protected from the development of fatty liver injury in response to chronic ethanol feeding, identifying an essential role for Egr‐1 in the development of chronic ethanol‐induced liver injury. Here we review recent studies aimed at understanding the mechanisms by which chronic ethanol enhances the LPS→ERK1/2→Egr‐1→ΤNFα pathway in Kupffer cells. These studies identify a critical role for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase‐derived reactive oxygen species in the activation of ERK1/2 and subsequent production of TNFα in Kupffer cells after chronic ethanol feeding.
Role of oxidative stress and Kupffer cells in hepatic fibrosis
Authors: Kawada Norifumi , Otogawa Kohji 
Published: May 2007

AbstractAlthough non‐alcoholic steatohepatitis (NASH) has become a common disease worldwide, its pathogenesis remains unclear. Establishment of a proper animal model is a prerequisite for analyzing the molecular mechanism of this disease. A NASH model has been developed using rabbits fed a high‐fat diet. These rabbits developed prominent fatty changes in hepatocytes. Hepatic fibrosis was seen around hepatocytes and the portal vein area. Apoptotic hepatocytes, which were rare in the intact liver, appeared in the liver of high‐fat diet‐fed rabbits. It is speculated that Kupffer cells/macrophages may play an important role in triggering the generation of oxidative stress in this model. Thus, this rabbit model is proposed for use in the molecular analysis of human NASH.
Role of retinoic acid receptor in steatohepatitis‐related tumor formation
Authors: Shiota Goshi 
Published: May 2007

AbstractRetinoic acid (RA) appears to play an important role in the pathophysiology of liver disease. However, this role remains to be clarified in detail. To explore the role of RA in the liver, transgenic mice that express RA receptor (RAR) α−dominant negative form in hepatocytes under the control of albumin promoter and enhancer, were developed. At 4 months of age the RAR α– dominant negative form transgenic mice developed microvesicular steatosis and spotty focal necrosis. The enzymes that are involved in mitochondrial β‐oxidation of fatty acids, including very‐long‐acyl‐CoA dehydrogenase, long‐acyl‐CoA dehydrogenase, and 3‐hydroxyacyl‐CoA dehydrogenase, were downregulated; in contrast, the enzymes that are involved in peroxisomal β‐oxidation, including acyl‐CoA oxidase and bifunctional enzyme, were upregulated. Expression of cytochrome p4504a10, cytochrome p4504a12, and cytochrome p4504a14 was increased, suggesting that ω‐oxidation of fatty acids in microsomes was accelerated. In addition, formation of H2O2 and 8‐hydroxy‐2′‐deoxyguanosine was increased. After 12 monthsof age, these mice developed hepatocellular carcinomaand adenoma of the liver. The incidence of tumor formation increased with age. Expression of β‐catenin and cyclin D1 was enhanced and the TCF‐4/β‐catenin complex was increased, whereas the RARα/β‐catenin complex was decreased. Feeding on a high‐RA diet reversed histological and biochemical abnormalities and inhibited the occurrence of liver tumors. These results suggest that hepatic loss of RA function leads to the development of steatohepatitis and liver tumors. In conclusion, RA plays an important role in preventing hepatocarcinogenesis in association with fatty acid metabolism and Wnt signaling.
Central role of mitochondria in metabolic regulation of liver pathophysiology
Authors: Sato Nobuhiro 
Published: May 2007

AbstractMitochondria play a central role in cellular energy metabolism. Oxidative phosphorylation occurs in the electron transport system of the inner mitochondrial membrane. Cytochrome aa3, b and c1 are encoded by mitochondrial DNA whereas cytochrome c is encoded by the nuclear gene, and these mitochondrial‐DNA dependent cytochromes are decreased and electron transport at complex II, III and IV is disturbed in liver carcinomas and during carcinogenesis. The more the decreased cytochrome and oxidase activity are seen, the more significant is the increase in reactive oxygen species (ROS) production. ROS produced in mitochondria may be the main cause of nuclear‐gene mutation in carcinogenesis. The mitochondrial dysfunction and overproduction of ROS plays a key role in progression of chronic hepatitis C and ethanol‐induced liver injury. Ethanol also causes bacterial translocation in the intestine and the resulting lipopolysaccharides (LPS) activates Kupffer cells to produce pro‐inflammatory cytokines. We suspect that non‐alcoholic steatohepatitis (NASH) also is the result of increased ROS production in Kupffer cells and hepatocytes.
A transition care programme which improves diabetes control and reduces hospital admission rates in young adults with Type 1 diabetes aged 15–25 years
Authors: Holmes‐Walker D. J. , Llewellyn A. C. , Farrell K. 
Published: May 2007

AbstractAims  To determine if a transition support programme for young adults with diabetes could maintain attendance at a specialist clinic, improve diabetes control and reduce acute hospital admissions with diabetic ketoacidosis (DKA) in 15–25‐year‐olds with Type 1 diabetes.Methods  A transition coordinator/diabetes educator arranged booking and rebooking of appointments for a young adult diabetes clinic based in an adult hospital between July 2001 and March 2006. An after‐hours phone support service was initiated. Data collected included source of referral, frequency of clinic attendance and HbA1c at each visit. Numbers of admissions and readmissions with DKA, length of stay and HbA1c on admission were recorded.Results  One hundred and ninety‐one young adults were referred. HbA1c at initial referral was 9.3 ± 2.17%. HbA1c significantly improved to 8.8 ± 1.9% (P < 0.001) after a median of five visits with a statistically significant fall in HbA1c of 0.13% per visit (P = 0.01). The greatest improvements were seen in those with starting HbA1c > 11% (−2.5 ± 2.3%, P < 0.001). Eighty‐two percent had attended appointments in the last 6 months. There was a significant reduction in DKA admissions falling by 1/3 (P = 0.05), and in readmissions a significant reduction in length of stay (−3.6 days, P = 0.02), over 3.5 years.Conclusions  If young adults are appropriately supported in adult services, clinic attendance is maintained, diabetes control is improved and hospital admission rates with DKA are reduced. The cost savings from reduced admissions covered the costs of the programme.
Reduced peripheral blood mitochondrial DNA content is not a risk factor for Type 2 diabetes
Authors: Singh R. , Hattersley A. T. , Harries L. W. 
Published: May 2007

AbstractAims  Mitochondrial depletion in pancreatic beta cells is known to reduce glucose stimulated insulin secretion. We aimed to determine whether the offspring of patients with early onset Type 2 diabetes had reduced peripheral blood mitochondrial content relative to control subjects and whether this could lead to a predisposition to type 2 diabetes in later life.Methods  We measured the levels of mitochondria relative to a single copy genomic target by real time polymerase chain reaction in a series of peripheral blood samples taken from the offspring of Caucasian patients with Type 2 diabetes and matched controls. Measures of insulin sensitivity and beta cell function were also taken.Results  In contrast with previous studies, mitochondrial DNA content was not decreased in the offspring of patients with Type 2 diabetes relative to matched controls in our cohort. Conversely, we noted a small proliferation in mitochondrial numbers in our case subjects. In agreement with these findings, no correlations with either insulin sensitivity or beta cell function were noted.Conclusions  Our results indicate that reduced mitochondrial DNA content in peripheral blood is not a risk factor for the development of Type 2 diabetes in the offspring of patients with early onset Type 2 diabetes.
The Centrality of Gender and Ethnic Identities across Individuals and Contexts
Authors: Turner Kelly L. , Brown Christia Spears 
Published: May 2007

AbstractThis study examined (1) whether 5‐ to 12‐year‐old children consider gender and ethnicity to be central and important components of their identity, (2) whether the relative centrality of these identity components differs across children, and (3) how the centrality of children's gender and ethnic identities is affected by a dynamic situational context of inclusion and exclusion. Results indicate that although gender and ethnicity are not the most important aspects of elementary schoolchildren's self‐concepts, both gender and ethnic identities differ among European‐American and ethnic minority group children, and those differences are greater in older children. In addition, children's gender identity is context‐dependent, but the exact nature of this flexibility is contingent on the existing centrality of their identity.