bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of folding dynamics and structural stability on the location of a hydrophobic pair in β‐hairpins
Authors: Imamura Hideo , Chen Jeff Z. Y.
Published: February 2006

We study the dependence of folding time, nucleation site, and stability of a model β‐hairpin on the location of a cross‐strand hydrophobic pair, using a coarse‐grained off‐lattice model with the aid of Monte Carlo simulations. Our simulations have produced 6500 independent folding trajectories dynamically, forming the basis for extensive statistical analysis. Four folding pathways, zipping‐out, middle‐out, zipping‐in, and reptation, have been closely monitored and discussed in all seven sequences studied. A hydrophobic pair placed near the β‐turn or in the middle section effectively speed up folding; a hydrophobic pair placed close to the terminal ends or next to the β‐turn encourages stability of the entire chain. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Fetal cardiac calcifications: report of four prenatally diagnosed cases and review of the literature
Authors: Simchen M. J. , Toi A. , Silver M. , Smith C. R. , Hornberger L. K. , Taylor G. , Chitayat D.
Published: February 2006

Fetal cardiac calcifications are defined as diffuse hyperechogenicities in the different layers of the heart. This is an uncommon fetal ultrasound finding associated with significant myocardial dysfunction. We report four cases with massive fetal myocardial calcifications detected on prenatal ultrasound at 18–22 weeks' gestation and associated, in all cases, with significant cardiac dysfunction. Detailed fetal echocardiographic evaluation, chromosome analysis, and an extensive search for intrauterine infection as a cause of these abnormalities, were carried out on all cases. A thorough autopsy was performed on all deceased fetuses and postnatal investigation of the sole survivor was performed. Two of our patients chose to interrupt their pregnancies, one fetus suffered intrauterine demise, and one child was born alive. In all of our cases the karyotypes were normal, and no specific infectious etiology or maternal autoantibody was noted. Histopathology findings in the non‐survivors included myo‐ and epicardial calcification maximal at the base of the heart. The living child has findings suggestive of an intrauterine infection, although no infectious entity was identified. Long‐term follow‐up showed sensorineural hearing loss and severe developmental delay. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
The impact of two‐dimensional versus three‐dimensional ultrasound exposure on maternal–fetal attachment and maternal health behavior in pregnancy
Authors: Sedgmen B. , McMahon C. , Cairns D. , Benzie R. J. , Woodfield R. L.
Published: February 2006

Objective

To explore the impact of timing and type of ultrasound, particularly three‐dimensional (3D), exposure on maternal–fetal attachment and maternal health behavior during pregnancy.

Methods

Subjects were 68 women aged 18 years or older expecting their first child who presented for a routine ultrasound scan at around either 12 or 18 weeks' gestation in Nepean Hospital, Western Sydney. Women completed questionnaires assessing maternal–fetal attachment and health behavior, and were then allocated arbitrarily to either two‐dimensional (2D) or 3D ultrasound examination. Repeat questionnaires were completed 1 week later.

Results

Maternal–fetal attachment increased after both 2D and 3D ultrasound exposure, and the effect was moderated by the timing of exposure, with women receiving their first ultrasound examination at around 12 weeks showing the greatest change. Alcohol consumption was the only behavior to show significant change following ultrasound exposure, with a reduction in the reported average number of drinks per week. There was no significant difference in the pattern of change for 2D compared with 3D ultrasound exposure, and no effect of ultrasound exposure on maternal perception of the fetus.

Conclusions

Ultrasound has a positive impact on maternal–fetal attachment, particularly in the first trimester. 3D ultrasound did not offer enhanced benefits. Associations between ultrasound exposure and alcohol consumption warrant further investigation. Larger samples are needed to clarify the moderating effects of gestational age and type of ultrasound exposure. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Insulin‐like Growth Factors (IGF) I and II Utilize Different Calcium Signaling Pathways in a Primary Human Parathyroid Cell Culture Model
Authors: Wong C. K. M. , Lai T. , Holly J. M. P. , Wheeler M. H. , Stewart C. E. H. , Farndon J. R.
Published: February 2006

Background

In most cell types, influx of calcium (Ca2+) induces a growth or secretory response. The opposite occurs in parathyroid (PTH), cells where there is an inverse relationship between intracellular Ca2+concentration and PTH secretion. We have examined the effects of calcium channel and metabolism modulators on insulin‐like growth factors (IGFs) in a parathyroid cell culture model.

Methods

Cell cultures were prepared from 9 patients undergoing operation for hyperparathyroidism. Following adhesion, the cells were transferred to serum‐free medium and dosed with IGF I, II ± ethyleneglycol‐bis(β‐aminoethyl)‐N, N, N′,N′‐tetraacetic acid (EGTA), nifedipine, nickel, 2‐aminoethoxy‐diphenylborate (2‐APB), or dantrolene. Proliferation (96 hours) was assessed by measuring tritiated thymidine incorporation and PTH release (1 and 3 hours) assayed by IRMA.

Results

Both IGF I and II increased DNA synthesis to 162.8% ± 10.6% (SEM) and 131.1% ± 7.7%, respectively (P< 0.05). EGTA at 0.2 mmol (ionized Ca2+0.2mmol) did not affect the response to both IGFs. EGTA at 2 mmol (ionized Ca2+0 mmol) reduced the DNA synthesis of IGF I and II to 29% and 26%, respectively (P< 0.05). Nifedipine and nickel (nonspecific Ca2+channel blocker) were equally potent in negating the mitogenic effects of both IGFs. 2‐APB (IP3R blocker) reduced the basal DNA synthesis to 51.3% ± 8.4% but had no effect on either IGF. Dantrolene (ryanodine receptor blocker) negated IGF II induced mitogenisis (74.2% ± 6.7%) and partially inhibited IGF I mitogenesis (123% ± 6%) (P< 0.05). The rate of PTH secretion was greater after IGF II stimulation than after IGF I stimulation.

Conclusions

IGFs I and II induce mitogenesis by different calcium signaling pathways. These data suggest that parathyroid cells may utilize different calcium signaling pathways to distinguish growth factors and serum calcium changes.
Preoperative Evaluation of Hepatic Vasculature by Three‐Dimensional Computed Tomographyin Patients Undergoing Hepatectomy
Authors: Kamiyama Toshiya , Nakagawa Takahito , Nakanishi Kazuaki , Kamachi Hirofumi , Onodera Yuya , Matsushita Michiaki , Todo Satoru
Published: February 2006

Background

Hepatectomy is particularly difficult when the tumor is large, close to the inferior vena cava or the main trunk of the hepatic or portal vein, or in the caudate lobe, as well as when the operation is a re‐hepatectomy, because two‐dimensional computed tomography (CT) often does not clearly show tumor location relative to blood vessels.

Study Design

To evaluate the efficacy of three‐dimensional computed tomography (3D‐CT), reconstructed from multidetector‐row computed tomography (MD‐CT) with contrast, MD‐CT was performed in 17 patients before hepatectomy.

Results

The third‐order branches of the hepatic artery and the portal vein were clearly shown in all cases. Both the hepatic vein, which drained the same segment that the portal vein fed, and the portal vein were also clearly shown. These vessels could be visualized from any perspective. In 2 patients who underwent hemihepatectomy, large tumors (23.0 and 17.0 cm) displaced the vasculature, but the positions of tumor and vessels could be precisely evaluated by 3D‐CT. In patients who required replacement of the vena cava with synthetic grafts, the distance and direction of pressure to IVC by tumor was accurately estimated by 3D‐CT. In patients who were limited to segmentectomy or partial hepatectomy because of prior hepatectomy or tumor position, evaluation of the glissons was facilitated by 3D‐CT.

Conclusions

Three‐dimensional‐CT was extremely useful for preoperative simulation because it provided important information that could not be obtained with 2D‐CT.
Cross‐National Variations in Behavioral Profiles Among Homeless Youth
Authors: Milburn Norweeta G. , Rotheram-Borus Mary Jane , Rice Eric , Mallet Shelley , Rosenthal Doreen
Published: February 2006

Cross‐national comparisons of homeless youth in Melbourne, Australia, and Los Angeles, CA, United States were conducted. Newly (n = 427) and experienced (n = 864) homeless youth were recruited from each site. Compared to Australia, homeless youth in the United States were younger, more likely to be in school or jail, demonstrated fewer sexual and substance use risk acts, fewer suicidal acts, and reported less need for social services. Across sites, experienced homeless youth were more likely to be older, male, engage in sexual and substance use, report greater need for social services, and make greater use of work, substance use, and health‐related services. Homeless youth have different behavioral profiles in Australia and the United States, reflecting differences in the effectiveness of service systems in the two countries in keeping youth with fewer problems out of homelessness.
Reward‐aversion circuitry in analgesia and pain: Implications for psychiatric disorders
Authors: Borsook David , Becerra Lino , Carlezon William A. , Shaw Marnie , Renshaw Perry , Elman Igor , Levine Jon
Published: February 2006

Sensory and emotional systems normally interact in a manner that optimizes an organism's ability to survive using conscious and unconscious processing. Pain and analgesia are interpreted by the nervous system as aversive and rewarding processes that trigger specific behavioral responses. Under normal physiological conditions these processes are adaptive. However, under chronic pain conditions, functional alterations of the central nervous system frequently result in maladaptive behaviors. In this review, we examine: (a) the interactions between sensory and emotional systems involved in processing pain and analgesia in the physiological state; (b) the role of reward/aversion circuitry in pain and analgesia; and (c) the role of alterations in reward/aversion circuitry in the development of chronic pain and co‐morbid psychiatric disorders. These underlying features have implications for understanding the neurobiology of functional illnesses such as depression and anxiety and for the development and evaluation of novel therapeutic interventions.
Differential gene expression in egg cells and zygotes suggests that the transcriptome is restructed before the first zygotic division in tobacco
Authors: Ning Jue , Peng Xiong-Bo , Qu Liang-Huan , Xin Hai-Ping , Yan Ting-Ting , Sun Mengxiang
Published: February 2006

We applied suppression subtractive hybridization and mirror orientation selection to compare gene expression profiles of isolated Nicotiana tabacum cv SR1 zygotes and egg cells. Our results revealed that many differentially expressed genes in zygotes were transcribed de novo after fertilization. Some of these genes are critical to zygote polarity and pattern formation during early embryogenesis. This suggests that the transcriptome is restructed in zygote and that the maternal‐to‐zygotic transition happens before the first zygotic division, which is much earlier in higher plants than in animals. The expressed sequence tags used in this study provide a valuable resource for future research on fertilization and early embryogenesis.
Failure of Surgery for Scaphoid Non-Union is Associated with Smoking
Authors: LITTLE C. P. , BURSTON B. J. , HOPKINSON-WOOLLEY J. , BURGE P.
Published: February 2006

Scaphoid fractures predominantly affect young men, in whom the UK smoking prevalence approaches 40%. We examined the association between smoking and failure of non-vascularized bone grafting and screw fixation for scaphoid non-union and delayed union in a retrospective cohort study. Adequate follow-up was obtained in 64 of 87 patients treated (74%). Union was defined as the presence of trabecular continuity on at least two films from a four-view radiographic series. Union was achieved in 47 of 64 cases. Seventeen were smokers. Thirteen of the 17 patients with non-union were smokers (relative risk 3.7; 95% CI: 1.3–10.1, p = 0.005). Proximal pole fractures, long injury-grafting interval and non-compliance were not more frequent in smokers than non-smokers. Smoking is strongly associated with failure of union after screw fixation and non-vascularized bone grafting of the scaphoid. Smokers should be advised to avoid smoking pre-operatively and during the healing period.
What Is the True Incidence of Horizontal Semicircular Canal Benign Paroxysmal Positional Vertigo?
Authors: Çakir Burak Ömür , Ercan İbrahim , Çakir Zeynep Alkan , Civelek Şenol , Sayin İbrahim , Turgut Suat
Published: February 2006

OBJECTIVE

To assess the correct incidence of horizontal semicircular canal (H‐SCC) benign paroxysmal positional vertigo (BPPV).

STUDY DESIGN

Retrospective assessment of patients with BPPV.

METHODS

All patients with BPPV were included and the rates of involvement of posterior, horizontal, and anterior SCCs were determined.

RESULTS

One hundred sixty‐nine patients with the diagnosis of BPPV were evaluated. One hundred forty‐four patients (85.2%) were found to have posterior SCC (P‐SCC) involvement, and there were 20 patients (11.8%) with horizontal SCC (H‐SCC) and 2 patients (1.2%) with anterior SCC (A‐SCC) involvement. Three patients (1.8%) had simultaneous H‐SCC and P‐SCC BPPV ipsilaterally. Geotropic nystagmus was seen in 17 out of 23 patients (73.9%) in roll test, and ageotropic nystagmus was seen in the remaining 6 patients (26.1%).

CONCLUSION

H‐SCC constitutes 13.6% of all BPPV cases. H‐SCC BPPV with geotropic nystagmus is more common. H‐SCC BPPV can coexist with ipsilateral P‐SCC BPPV. However, in some cases of H‐SCC BPPV, Dix‐Hallpike maneuver can cause vertigo and horizontal nystagmus. This may be confused with P‐SCC BPPV. Therefore, the roll test must be performed in all cases in addition to Dix‐Hallpike maneuver and both ears must be evaluated with respect to all SCCs for BPPV.

EBM rating: C‐4

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
The Role of Ostiomeatal Complex Obstruction in Maxillary Fungus Ball
Authors: Tsai Tung‐Lung , Guo Yuan‐Ching , Ho Ching‐Yin , Lin Ching‐Zong
Published: February 2006

OBJECTIVE

The aim of this study was to clarify the role of ostiomeatal complex obstruction in maxillary fungus ball.

STUDY DESIGN AND SETTING

Comparative study in a hospital setting of the mean Lund‐Mackay scores for the anterior ethmoid and frontal sinuses of 54 versus 48 patients with maxillary fungus ball versus chronic unilateral rhinosinusitis, respectively.

RESULTS

In cases with partial opacification in the maxillary sinus, the anterior ethmoid and frontal sinuses were diseased in the chronic unilateral rhinosinusitis group but not in the maxillary fungus ball group. In cases with total opacification in the maxillary sinuses, all anterior ethmoid and frontal sinuses in both groups were diseased, but the disease condition of the frontal sinuses was significantly less severe in the maxillary fungus ball group (P < 0.001).

CONCLUSION AND SIGNIFICANCE

In this era of evidence‐based medicine, we provide statistical data supporting the principle that maxillary fungus ball is not associated with osteomeatal complex obstruction and that another as‐yet‐unexplained mechanism must be responsible.

EBM rating: B‐3b

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
Revision Chronic Ear Surgery
Authors: Kaylie David M. , Gardner Edward K. , Jackson C. Gary
Published: February 2006

OBJECTIVE

To report results of revision chronic ear surgery following guidelines of the American Academy of Otolaryngology–Head and Neck Surgery and to establish expectations for infection and cholesteatoma control and hearing outcomes.

STUDY DESIGN

Retrospective case review of all patients who underwent revision chronic ear surgery from January 1, 1990 to December 31, 2000. Revision chronic ear surgery included canal wall up and canal wall down procedures with ossicular chain reconstruction performed as needed. Cholesteatoma control, hearing improvement, and closure of middle ear space are main outcome measures.

SETTING

Tertiary referral center.

RESULTS

Cholesteatoma recurrence rate was 57% at 1 year after surgery and 14% in patients with a minimum of a 5‐year follow‐up. Disease control was achieved in 96% of patients. Hearing was significantly improved in all surgical groups. Closure of the air‐bone gap for revision partial ossicular replacement prosthesis cases (PORP) to less than 20 dB occurred in 50% of patients. Closure of the air‐bone gap to within 30 dB for revision total ossicular replacement prosthesis (TORP) occurred in 60% of patients. Canal wall down status had a significant impact on hearing results after PORPs and TORPs; patients with intact canal walls had significantly better hearing results. Diagnosis of cholesteatoma significantly impacted hearing results for TORPs but not PORPS.

CONCLUSIONS

Cholesteatoma control rates after revision surgery are similar to primary cases. Significant improvement in hearing can be expected after revision chronic ear surgery. Hearing results after a revision surgery that requires a PORP is worse than primary cases and is canal wall status dependant. Closure of the middle ear space and creation of a safe dry ear can be expected after revision chronic ear surgery.

SIGNIFICANCE

This is a review of a large series of exclusively revision chronic ear surgery.

EBM rating: C‐4

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
Relationship between Rhinosinusitis Symptoms and Mucociliary Clearance Time
Authors: Boatsman Justin E. , Calhoun Karen H. , Ryan Matthew W.
Published: February 2006

OBJECTIVE

To determine the correlation between rhinosinusitis symptoms as assessed by the Sino‐Nasal Outcomes Test‐20 (SNOT‐20) and mucociliary clearance as assessed by the saccharin method.

STUDY DESIGN AND SETTING

This was a cross‐sectional study of 50 adult volunteers. Subjects completed the SNOT‐20, and mucociliary clearance was determined with the saccharine method. Correlation coefficients (Spearman's Rho) were calculated for the global SNOT‐20 score.

RESULTS

The SNOT‐20 scores varied from 20 to 54 (mean 30.28) with a possible range of 20 to 100. Clearance times varied from 418 to 2865 seconds (mean 999). There was no significant correlation between global SNOT‐20 score and clearance time (r = 0.196).

CONCLUSIONS

There is no significant correlation between rhinosinusitis symptoms as assessed by SNOT‐20 scores and mucociliary clearance.

SIGNIFICANCE

Mucociliary clearance is important for the health of the sinonasal cavities, but clearance time does not appear to be associated with symptom severity in the population studied.

EBM rating: A‐1b

© 2006 American Academy of Otolaryngology‐Head and Neck Surgery Foundation, Inc. All rights reserved.
Perioperative Management of Sickle Cell Disease Children Undergoing Adenotonsillectomy
Authors: Duke Rebecca L. , Scott J. Paul , Panepinto Julie A. , Flanary Valerie A.
Published: February 2006

OBJECTIVE

To determine if outpatient tailored perioperative management has the same complication rate as that previously published for sickle cell disease (SCD) children who undergo adenotonsillectomy.

STUDY DESIGN AND SETTING

Retrospective chart review of SCD children who underwent tonsillectomy with outcome measures of perioperative management and postsurgical complications.

RESULTS

Of 41 patients, 61% were monitored for <24 hours with the average length of stay being 2 days (range, 1 to 10). Postoperative complications were noted in 9 (22%) patients, including 8 (20%) with hypoxia, 4 (10%) fever, 3 (8%) acute chest syndrome, and 1 (2.4%) airway fire, which are similar to the published literature.

CONCLUSIONS

Current literature supports extensive perioperative management with hospital stays averaging 3 to 5 days. These data demonstrate that the majority of these patients can be managed with <24‐hour hospitalization stays with similar complication rates as previously described in the literature.

SIGNIFICANCE

This study establishes a new paradigm for perioperative management of SCD children who undergo adenotonsillectomy.

EBM rating: C‐4

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
Assessment of Phonatory Function by the Airway Interruption Method: Age‐Related Changes
Authors: Makiyama Kiyoshi , Yoshihashi Hidetaka , Park Risa , Shimazaki Nahoko , Nakai Momoka
Published: February 2006

OBJECTIVE

In order to ascertain age‐related changes in phonatory function, an aerodynamic phonatory function test based on the airway interruption method was conducted.

STUDY DESIGN

Subjects were 142 men and 144 women aged between 20 and 79 years. No subjects demonstrated abnormalities of sound quality. The test was conducted using the Nagashima PS77E phonatory function analyzer. Subjects were instructed to phonate at the most comfortable pitch and intensity, and fundamental frequency (F0), sound pressure level (SPL), mean flow rate (MFR), expiratory lung pressure (EP), and airway resistance were determined.

RESULTS

F0 was lower among women aged ≥50 years. EP was lower for women aged ≥70 years than for those in other age groups. For both genders, airway resistance was lower for those aged ≥70 years when compared to other age groups.

CONCLUSIONS

Among women, F0 was lower aged ≥50 years. In advanced age, EP and airway pressure decreased among women and airway resistance decreased among men.

EBM rating: C‐4

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
Clinical Performance of Children Following Revision Surgery for a Cochlear Implant
Authors: Fayad Jose N. , Eisenberg Laurie S. , Gillinger Melinda , Winter Margaret , Martinez Amy S. , Luxford William M.
Published: February 2006

OBJECTIVES

The purpose of this study was to describe the causes for revision surgery and to compare clinical performance before and after surgery in children who required electrode reinsertion.

STUDY DESIGN AND SETTINGS

Soundfield thresholds and speech recognition scores were compared before device failure and following electrode reinsertion. Temporal bones from a deceased adult implant user who underwent bilateral revision implantation were analyzed.

RESULTS

Histopathology in the adult temporal bones revealed new bone formation in the scala tympani and substantially reduced spiral ganglion counts, with open‐set speech recognition realized. Of 28 children undergoing revision surgery, 18 required electrode reinsertion. With the exception of 1 patient with severe cochlear malformation, new electrode arrays were fully inserted without difficulty. Clinical outcomes between pre‐device failure and post‐electrode reinsertion did not differ statistically.

CONCLUSION AND SIGNIFICANCE

Electrode reinsertion is technically feasible in the pediatric population. The majority of children recover their prerevision clinical performance.
A 1500-year record of temperature and glacial response inferred from varved Iceberg Lake, southcentral Alaska
Authors: Loso Michael G. , Anderson Robert S. , Anderson Suzanne P. , Reimer Paula J.
Published: February 2006

We present a varve thickness chronology from glacier-dammed Iceberg Lake in the southern Alaska icefields. Radiogenic evidence confirms that laminations are annual and record continuous sediment deposition from A.D. 442 to A.D. 1998. Varve thickness is positively correlated with Northern Hemisphere temperature trends, and more strongly with a local, ∼600 yr long tree ring width chronology. Varve thickness increases in warm summers because of higher melt, runoff, and sediment transport (as expected), but also because shrinkage of the glacier dam allows shoreline regression that concentrates sediment in the smaller lake. Varve thickness provides a sensitive record of relative changes in warm season temperatures. Relative to the entire record, temperatures implied by this chronology were lowest around A.D. 600, warm between A.D. 1000 and A.D. 1300, cooler between A.D. 1500 and A.D. 1850, and have increased dramatically since then. Combined with stratigraphic evidence that contemporary jökulhlaups (which began in 1999) are unprecedented since at least A.D. 442, this record suggests that 20th century warming is more intense, and accompanied by more extensive glacier retreat, than the Medieval Warm Period or any other time in the last 1500 yr.
Word learning deficit among Chinese dyslexic children
Authors: SUK-HAN HO CONNIE , CHAN DAVID W. , TSANG SUK-MAN , LEE SUK-HAN , CHUNG KEVIN K. H.
Published: February 2006

The present study examined word learning difficulties in Chinese dyslexic children, readers of a nonalphabetic script. A total of 105 Hong Kong Chinese children were recruited and divided into three groups: Dyslexic (mean age 8;8), CA control (mean age 8;9), and RL control (mean age 6;11). They were given a word learning task and a familiar word writing task. It was found that the Dyslexic group performed less well than the RL group in learning irregular words over trials but not the regular ones. Error analyses showed that the Dyslexic group made more orthographic and word association errors but less intra-wordlist interference errors than the RL control group. The Dyslexic group also performed significantly less well than both control groups in writing familiar words (e.g. their own name). These findings suggest that Chinese dyslexic children have difficulty learning new words, especially irregular ones, and retaining overlearned words in long-term memory. We conclude that Chinese dyslexic children have a specific impairment in word learning like their alphabetic counterparts.
Note of clarification on the coding of light verbs in ‘Semantic generality, input frequency and the acquisition of syntax’ (Journal of Child Language 31, 61–99)
Authors: THEAKSTON ANNA L. , LIEVEN ELENA V. M. , PINE JULIAN. M. , ROWLAND CAROLINE F.
Published: February 2006

In our recent paper, ‘Semantic generality, input frequency and the acquisition of syntax’ (Journal of Child Language31, 61–99), we presented data from two-year-old children to examine the question of whether the semantic generality of verbs contributed to their ease and stage of acquisition over and above the effects of their typically high frequency in the language to which children are exposed. We adopted two different categorization schemes to determine whether individual verbs should be considered to be semantically general, or ‘light’, or whether they encoded more specific semantics. These categorization schemes were based on previous work in the literature on the role of semantically general verbs in early verb acquisition, and were designed, in the first case, to be a conservative estimate of semantic generality, including only verbs designated as semantically general by a number of other researchers (e.g. Clark, 1978; Pinker, 1989; Goldberg, 1998), and, in the second case, to be a more inclusive estimate of semantic generality based on Ninio's (1999a,b) suggestion that grammaticalizing verbs encode the semantics associated with semantically general verbs. Under this categorization scheme, a much larger number of verbs were included as semantically general verbs.
Perspective-shifts in event descriptions in Tamil child language
Authors: NARASIMHAN BHUVANA , GULLBERG MARIANNE
Published: February 2006

Children are able to take multiple perspectives in talking about entities and events. But the nature of children's sensitivities to the complex patterns of perspective-taking in adult language is unknown. We examine perspective-taking in four- and six-year-old Tamil-speaking children describing placement events, as reflected in the use of a general placement verb (veyyii ‘put’) versus two fine-grained caused posture expressions specifying orientation, either vertical (nikka veyyii ‘make stand’) or horizontal (paDka veyyii ‘make lie’). We also explore whether animacy systematically promotes shifts to a fine-grained perspective. The results show that four- and six-year-olds switch perspectives as flexibly and systematically as adults do. Animacy influences shifts to a fine-grained perspective similarly across age groups. However, unexpectedly, six-year-olds also display greater overall sensitivity to orientation, preferring the vertical over the horizontal caused posture expression. Despite early flexibility, the factors governing the patterns of perspective-taking on events are undergoing change even in later childhood, reminiscent of U-shaped semantic reorganizations observed in children's lexical knowledge. The present study points to the intriguing possibility that mechanisms that operate at the level of semantics could also influence subtle patterns of lexical choice and perspective-shifts.
Editorial
Authors: BAVIN EDITH L. , DALE PHILIP
Published: February 2006

We are extremely pleased and honoured to be taking over as co-editors of the Journal of Child Language. We follow an impressive list of previous editors. We know it will be a challenging role, but we are excited by the challenge and look forward to working together to meet it.
Comparison of a waterless hand-hygiene preparation and soap-and-water hand washing to reduce coliforms on hands in animal exhibit settings
Authors: DAVIS M. A. , SHENG H. , NEWMAN J. , HANCOCK D. D. , HOVDE C. J.
Published: February 2006

Outbreaks of enteric disease associated with exposure to live animals on exhibit have occurred with increasing frequency in recent years. Possibly the most important pathogen causing such outbreaks is Escherichia coli O157:H7, because of the serious illness it can cause. Hand hygiene is consistently protective against disease among persons exposed to animals implicated in these outbreaks. Livestock barns have limited hand-washing facilities, therefore a waterless hand-sanitizing gel would be a potentially preventive measure readily available to visitors and animal exhibitors. This study compared the reduction of bacterial counts on hands of animal exhibitors when soap and water was used or when an ethanol-based hand gel was used after animal handling. Participants were youth and adults involved with showing livestock. The sanitation methods were similar in reducing the total bacteria and coliform counts on the hands of the participants (Wilcoxon rank sum test P values 0·12 and 0·69 respectively).
Coastal effects on radar propagation in atmospheric ducting conditions
Authors: Atkinson B. W. , Zhu M.
Published: February 2006

Two models were used to assess the effects of coastal characteristics on radar propagation in ducting conditions in the Persian Gulf. The NCAR/Penn State MM5 model simulated atmospheric conditions at a 5‐km horizontal spatial and hourly temporal resolution on a day on which observations of ducts existed. The output from this model was input to the AREPS propagation model to produce radar coverage over coastal areas. Four factors influenced radar propagation: the sea breeze; coastal configuration; orography; and ambient wind. The sea breeze alone allowed propagation to extend about 100 km inland in a layer 200 m deep. When the breeze was aided by a following ambient wind the propagation layer extended for 150 km and was 400 m deep. A coastal indentation caused differences in depth and intensity of propagation over a distance of about 30 km parallel to the coast in which the indentation occurred. Steep near‐coastal orography blocked radar propagation. Copyright © 2006 Royal Meteorological Society.
A Bayesian approach for multi‐model downscaling: Seasonal forecasting of regional rainfall and river flows in South America
Authors: Coelho C. A. S. , Stephenson D. B. , Doblas‐Reyes F. J. , Balmaseda M. , Guetter A. , van Oldenborgh G. J.
Published: February 2006

This study addresses three issues: spatial downscaling, calibration, and combination of seasonal predictions produced by different coupled ocean‐atmosphere climate models. It examines the feasibility of using a Bayesian procedure for producing combined, well‐calibrated downscaled seasonal rainfall forecasts for two regions in South America and river flow forecasts for the Paraná river in the south of Brazil and the Tocantins river in the north of Brazil. These forecasts are important for national electricity generation management and planning. A Bayesian procedure, referred to here as forecast assimilation, is used to combine and calibrate the rainfall predictions produced by three climate models. Forecast assimilation is able to improve the skill of 3‐month lead November‐December‐January multi‐model rainfall predictions over the two South American regions. Improvements are noted in forecast seasonal mean values and uncertainty estimates. River flow forecasts are less skilful than rainfall forecasts. This is partially because natural river flow is a derived quantity that is sensitive to hydrological as well as meteorological processes, and to human intervention in the form of reservoir management. Copyright © 2006 Royal Meteorological Society.
Salar de Atacama basin: A record of compressional tectonics in the central Andes since the mid‐Cretaceous
Authors: Arriagada Cesar , Cobbold Peter R. , Roperch Pierrick
Published: February 2006

The Salar de Atacama basin lies in the inner fore arc of northern Chile. Topographically and structurally, it is a first‐order feature of the central Andes. The sedimentary fill of the basin constrains the timing and extent of crustal deformation since the mid‐Cretaceous. We have studied good exposures along the western edge of the basin and have correlated them with seismic reflection sections and data from an exploration well. Throughout most of its history, the basin developed in a foreland setting, during periods of thin‐skinned and thick‐skinned thrusting. Growth strata provide evidence for coeval sedimentation and thrust motions during mid‐Cretaceous, Paleogene, and Neogene times. Pre‐Neogene deformation was significant in the basin and in surounding areas of the early central Andes. Models that attempt to explain the current thickness of the central Andes should consider Late Cretaceous and Paleogene shortening, as well as the more obvious Neogene and Quaternary shortening.
Atmospheric sounding over the winter Kuroshio Extension: Effect of surface stability on atmospheric boundary layer structure
Authors: Tokinaga Hiroki , Tanimoto Youichi , Nonaka Masami , Taguchi Bunmei , Fukamachi Tomohiro , Xie Shang‐Ping , Nakamura Hisashi , Watanabe Tomowo , Yasuda Ichiro
Published: February 2006

Shipboard radiosonde surveys were conducted during the 2003‐04 winter east of Japan to study atmospheric boundary layer (ABL) structure over the Kuroshio Extension. ABL displayed large variations in vertical structure, most of which are attributable to changes in atmospheric surface stability. Where the surface atmosphere was unstable (neutral) as measured by the sea‐air temperature difference, surface turbulent heat flux increased (decreased) and a mixed‐layer developed (undeveloped) with weakened (intensified) vertical wind shear. A linear regression analysis indicates that ABL height tends to increase by 1km as the sea‐air temperature difference increases by 7°C or surface turbulent heat flux by 500 Wm−2. While meridional thermal advection by weather disturbances seems to cause much of atmospheric stability variability during the 43‐day surveys, the strong sensitivity of vertical mixing and wind shear to stability is consistent with the observed in‐phase co‐variability of SST and surface wind from satellite on monthly and longer timescales.
An explanation of the Voyager paradox: Particle acceleration at a blunt termination shock
Authors: McComas D. J. , Schwadron N. A.
Published: February 2006

Voyager 1 recently crossed the termination shock at the edge of our heliosphere. In contrast to the expectations of essentially all prior models, however, Voyager 1 did not observe the source of Anomalous Cosmic Rays (ACRs) as had been widely anticipated. We show here that the dearth of higher energy particles near the nose of the heliosphere is a natural consequence of the magnetic geometry in the region ahead of a flattened shock. Particle energization happens primarily back along the flanks of the shock where the injection energy is lower and where the magnetic field has had progressively longer connection times to accelerate particles. In addition to explaining the most baffling aspects of the Voyager 1 observations, this paradigm makes explicit predictions about what should be observed when Voyager 2 reaches the termination shock, significantly further back from its nose.
Quasi‐linear theory of anomalous resistivity
Authors: Yoon Peter H. , Lui Anthony T. Y.
Published: February 2006

Magnetic reconnection is a favored mechanism for understanding charged‐particle acceleration phenomena in space and laboratory plasmas. A change in magnetic field line topology is envisioned in magnetic reconnection to release the stored magnetic field energy. In order for this to take place, some form of dissipation to break the frozen‐in condition is required. Since the classical resistivity is often inadequate for collisionless plasmas, anomalous resistivity via charged particles interacting with fluctuating electromagnetic fields is customarily invoked. However, anomalous resistivity is often modeled rather than computed from theory. In this article, we formulate the theory of anomalous transport from first principles. It is found that the effect of fluctuations can be defined through three anomalous transport terms governing momentum and energy transport and the resistivity. To illustrate the utility of these derived equations, examples that bear relevance to the consideration of breakdown in the frozen‐in condition in magnetic reconnection are discussed.
Southern African crustal evolution and composition: Constraints from receiver function studies
Authors: Nair Shaji K. , Gao Stephen S. , Liu Kelly H. , Silver Paul G.
Published: February 2006

Stacking of approximately 1500 radial receiver functions recorded at about 80 broadband seismic stations deployed in southern Africa reveals systematic spatial variations in the ratio of crustal P and S wave velocities (ϕ), crustal thickness (H), and the amplitude of the converted Moho phases (R). The eastern Zimbabwe and the southern Kaapvaal cratons are characterized by small H (∼38 km), small ϕ (∼1.73), and large R (∼0.15) values, suggesting that the relatively undisturbed Archean crust beneath southern Africa is separated from the mantle by a sharp Moho and is felsic in composition. The Limpopo belt, which was created by a collisional event at 2.7 Ga, displays large H (∼43 km) but similar ϕ and R values relative to the cratonic areas. The Bushveld Mafic Intrusion Complex and its surrounding areas show large ϕ (∼1.78), large H (∼43 km), and small R (∼0.11) values, reflecting the intrusion of mafic material into the original crust as a result of the Bushveld event at 2.05 Ga. Excluding the Bushveld, the spatially consistent and age‐independent low ϕ accentuate the difference between felsic crustal composition and more mafic island arcs that are thought to be the likely source of continental material. Within such an island arc model, our data, combined with xenolith data excluding mantle delamination in cratonic environments, suggest that the modification to a felsic composition (e.g., by the partial melting of basalt and removal of residue by delamination) is restricted to have occurred during the collision between the arcs and the continent.
Glacial erosion, evolution of river long profiles, and the organization of process domains in mountain drainage basins of coastal British Columbia
Authors: Brardinoni Francesco , Hassan Marwan A.
Published: February 2006

In glaciated British Columbia, Canada, Quaternary climate changes are responsible for profound spatial reorganization of Earth surface processes. These changes have left a landscape characterized by topographic anisotropy associated with a hierarchy of glacial troughs. The evolution of glaciated landscapes is examined by analyzing the structure of geomorphic process domains and channel long profiles. To identify process domains we use channel surveys and GIS analysis to construct slope‐area transects of the channel network. This analysis reveals generalized process‐form disequilibrium with a mismatch between topographic signatures and currently active geomorphic process domains. At the landscape scale of “source” colluvial channels (contributing area <1 km2), the glacial/paraglacial signature commonly overrides that produced by contemporary debris flows. Along the axis of former ice flows, relict glacial cirques introduce a “hanging” fluvial domain at contributing areas as small as 8 × 10−2 km2 and produce complex channel long profiles similar to those observed for rivers responding to tectonic forcing. Slope‐area relations typical of unglaciated equilibrium environments do not apply here. The concept of process domains appears to hold, however, some major glacially forced modifications in the alluvial‐colluvial transition are observed and the definition of a depositional colluvial subdomain is proposed. Comparison between field‐ and GIS‐measured slopes reveals that GIS‐associated error is not uniform between process domains, and that GIS‐based plots do not successfully discriminate field‐based process domains. The combination of glacial and post‐glacial fingerprints and the effects of ongoing Earth surface processes generate a complex landscape whose glacial signatures may persist until the onset of the next ice age.
Seasonal phytoplankton blooms associated with monsoonal influences and coastal environments in the sea areas either side of the Indochina Peninsula
Authors: Tang Dan Ling , Kawamura Hiroshi , Shi Ping , Takahashi Wataru , Guan Lei , Shimada Teruhisa , Sakaida Futoki , Isoguchi Osamu
Published: February 2006

The Gulf of Thailand (GoT) is a semienclosed sea on the west and southwest side of the Indochina Peninsula and connects with the near‐coastal waters of the South China Sea (SCS) on the east and northeast side of the Malay Peninsula. The objective of the present study is to understand dynamic features of the phytoplankton biology in the GoT and the nearby SCS, on both sides of the Indochina Peninsula, using remote‐sensing measurements of chlorophyll‐a (Chl a), sea surface temperature (SST), and surface vector winds obtained during the period from September 1997 to March 2003. Results show that seasonal variations of the phytoplankton blooms are primarily controlled by the monsoonal winds and related coastal environments. The GoT and the near‐coastal SCS have a peak in the averaged monthly Chl a in December and January, which is associated with the winter northeaster monsoon. The near‐coastal SCS have another big peak in the averaged monthly Chl a in summer (July to September), which is associated with the summer southwest monsoon. The offshore bloom in the GoT occurs in its southern part and enhances the December–January peak of averaged monthly Chl a. By contrast, the offshore bloom in the nearby SCS is observed northeast of the Peninsula, and represents the primary source of the July–September peak Chl a. Here the coastal upwelling associated with the offshore Ekman transport caused by the coastal surface winds parallel to the Vietnam east coast gives physical conditions favorable to the development of offshore phytoplankton blooms. The Mekong River discharge waters flow in different directions, depending on the monsoon winds, and contributes to seasonal blooms on both sides of the Peninsula.
Two-dimensional tunneling Hamiltonian treatment of the microwave spectrum of 2-methylmalonaldehyde
Authors: Chou Yung-Ching , Hougen Jon T.
Published: February 2006

The molecule 2-methylmalonaldehyde (2-MMA) exists in the gas phase as a six-membered hydrogen-bonded ring [HO–CHC(CH3)–CHO] and exhibits two large-amplitude motions, an intramolecular hydrogen transfer and a methyl torsion. The former motion is interesting because the transfer of the hydrogen atom from the hydroxyl to the carbonyl group induces a tautomerization in the ring, i.e., HO–CHC(CH3)–CHO→OCH–C(CH3)CH–OH, which then triggers a 60° internal rotation of the methyl group attached to the ring. The microwave spectra of 2-MMA-d0, 2-MMA-d1, and 2-MMA-d3 were studied previously by Sanders [J. Mol. Spectrosc. 86, 27 (1981)], who used a rotating-axis-system program for two-level inversion problems to fit rotational transitions involving the nondegenerate A(+) and A(−) sublevels to several times their measurement uncertainty. A global fit could not be carried out at that time because no appropriate theory was available. In particular, observed-minus-calculated residuals for the E(+) and E(−) sublevels were sometimes as large as several megahertz. In the present work, we use a tunneling-rotational Hamiltonian based on a G12m group-theoretical formalism to carry out global fits of Sanders’ 2-MMA-d0 and 2-MMA-d1 [DO–CHC(CH3)–CHO] spectra nearly to measurement uncertainty, obtaining root-mean-square deviations of 0.12 and 0.10MHz, respectively. The formalism used here was originally derived to treat the methylamine spectrum, but the interaction between hydrogen transfer and CH3 torsion in 2-MMA is similar, from the viewpoint of molecular symmetry, to the interaction between CNH2 inversion and CH3 torsion in methylamine. These similarities are discussed in some detail.
Killing vectors in asymptotically flat space-times. II. Asymptotically translational Killing vectors and the rigid positive energy theorem in higher dimensions
Authors: Chruściel Piotr T. , Maerten Daniel
Published: February 2006

We show that the borderline cases in the proof of the positive energy theorem for initial data sets, on spin manifolds, in dimensions n⩾3, are only possible for initial data arising from embeddings in Minkowski space-time.
Optimal estimation of quantum observables
Authors: D’Ariano Giacomo Mauro , Giovannetti Vittorio , Perinotti Paolo
Published: February 2006

We consider the problem of estimating the ensemble average of an observable on an ensemble of equally prepared identical quantum systems. We show that, among all kinds of measurements performed jointly on the copies, the optimal unbiased estimation is achieved by the usual procedure that consists in performing independent measurements of the observable on each system and averaging the measurement outcomes.
Formal and analytical integrability of the Bianchi IX system
Authors: Llibre Jaume , Valls Clàudìa
Published: February 2006

In this paper we provide a complete description of the first integrals of the classical Bianchi IX system that can be described by a general class of formal power series. As a corollary we also obtain a complete description of some of its analytic first integrals in a neighborhood of the origin. In particular, we prove that the system is not completely integrable by analytic first integrals.
A systematic derivation of the Riemannian Barrett-Crane intertwiner
Authors: Maran Suresh K.
Published: February 2006

The Barrett-Crane intertwiner for the Riemannian general relativity is systematically derived by solving the quantum Barrett-Crane constraints corresponding to a tetrahedron (except for the nondegeneracy condition). It was shown by Reisenberger that the Barrett-Crane intertwiner is the unique solution. The systematic derivation can be considered as an alternative proof of the uniqueness. The new element in the derivation is the rigorous imposition of the cross-simplicity constraint.