bluuebunny/crossref_metadata_2025 huggingface dataset:
R430 – Glycogen Depletion for Study of Neuromuscular Connectivity
Authors: Kunibe Isamu , Zealear David L , Katada Akihiro , Singh Vikas P. , Bekeny James , Kamdar Biren Bharat , Harabuchi Yasuaki , Billante Cheryl Rainey
Published: August 2008

Problem

A useful technique for characterizing connectivity between nerve and muscle involves prolonged electrical stimulation of nerve fibers to deplete glycogen in their target muscle fibers. Depleted muscle fibers appear blank when stained by the PAS technique. Unfortunately, results are inconsistent over a wide range of stimulus paradigms. The aim of this study was to identify other factors that may impact glycogen depletion.

Methods

Glycogen depletion was examined in the rat medial gastrocnemius muscle because of the presence of aerobic fiber types I and IIA, which are resistant to depletion. Tension and EMG were monitored during maximal stimulation of transected sciatic nerve with a 333 msec pulse train delivered at 40 Hz every second over a period of 1 hour. Once an effective paradigm was identified, depletion of an entirely aerobic muscle (i.e., soleus) was evaluated.

Results

Animals maintained in a light plane of anesthesia with a steady rate of pentobarbital IP infusion showed an average depletion of only 72%. Animals administered a progressively increasing level of anesthesia with continued stimulation until complete loss of muscular response showed a significantly greater depletion of 96%. However, when this paradigm was applied to the soleus, only 37% of the muscle depleted. Further investigation determined that co‐contraction of gastrocnemius with soleus resulted in unloading of the slower soleus. Disruption of the gastrocnemius insertion on the Achilles tendon shifted the load to the soleus and increased soleus depletion to 93%.

Conclusion

Muscle fibers of any motor unit type can be identified with 93–96% accuracy when nerve stimulation is applied to an isometrically loaded muscle that is in a state of progressive barbiturate anesthesia.

Significance

Glycogen depletion provides a method for identifying the number, types, and distribution of muscle fibers in a muscle that have reinnervated, important in the assessment of nerve regeneration.

Support

NIH grants R01 DC001149 and R01 DC008429.
R433 – The Anterior Epitympanum
Authors: Abou‐Bieh Alaa A. , Haberkamp Thomas J , Al‐Abdulhadi Khalid A , Al‐Tubaikh Jarah Ali
Published: August 2008

Problem

Early studies report detailed microscopic anatomy of the anterior epitympanum, yet none describe its anatomy from an endoscopic point of view.

Methods

Thirty‐five temporal bones were dissected, and the anatomic details were studied utilizing an operating microscope and otoendoscopes with 0o, 30o and 70o angles and 2.7 and 3 mm diameters.

Results

Marked variation in the size and shape of the anterior epitympanum was observed. The recess was found in all of the 35 bones. In 43% of the specimens, the main cavity was above the tensor tympanic fold, it was best endoscopically approached via the posterior transmastoid approach. But in 49% of the specimens, because the recess was divided into two cavities by the tensor tympanic fold, it necessitated both the transmastoid and the transcanal routes to endoscopically approach it. While in 8% of specimens, it was mainly endoscopically approached via the transcanal approach, as the recess was contiguous with the eustachian tube.

Conclusion

The shape of the anterior epitympanum is influenced by the relation between the cavities above and below the tensor tympanic fold. The incorporation of otoendoscopes helps in more exposure of its different types with less aggressive approaches.

Significance

Review the added value of intra‐operative use of otoendoscopes to approach the different areas of the anterior epitympanic region.
R435 – Stapedius Muscle Relations to the Facial Canal
Authors: Abou‐Bieh Alaa A. , Haberkamp Thomas J , Al‐Tubaikh Jarah Ali
Published: August 2008

Problem

The gross anatomical variations of the stapedius muscle and its relations to the facial nerve canal.

Methods

Thirty‐five temporal bones were dissected, and the anatomic details were studied utilizing an operating microscope and otoendoscopes with 0o, 30o and 70o angles and 2.7 and 3 mm diameters. The muscle origin, its course in its bony sulcus with its relation to the facial nerve canal, the tendon and its insertion were studied.

Results

Marked variations in the origin, size, and course of the muscle in its bony sulcus were detected. The shape of the sulcus itself and its relation to the facial nerve canal varied also, both mainly influenced by the sinus tympani development. These variations affected the shape and length of the tendon and the pyramidal eminence. In addition, they influenced the site of tendon insertion into the stapes. The presence of ectopic muscle bundles was confirmed in one specimen.

Conclusion

The stapedius muscle anatomy can vary significantly from one temporal bone to another. In some situations these variations can be of surgical importance worse enough to be recognized.

Significance

To add important unrecognized data to the surgical anatomy of the temporal bone.
R438 – Medication Effects on Vestibular Rehabilitation in PTMAD
Authors: Donaldson Chadwick J , Hoffer Michael E , Gottshall Kim R , Healy David Y , Balough Ben J
Published: August 2008

Problem

Do migraine prophylactic medications effect the vestibular rehabilitation of individuals with Post‐Traumatic Migraine Associated Dizziness (PTMAD)?

Methods

Traumatic Brain Injury (TBI) is a common cause of neurologic disorders with a reported incidence in the literature between 180 to 500 per 100000. Individuals affected by mild TBI have a diverse range of symptoms that include but are not limited to dizziness, concentration difficulty, migraine headaches, emotional lability, nausea, anosmia, sensitivity to light and sounds. Evidence of post‐traumatic migraine associated dizziness (PTMAD), following mild TBI, have been described and characterized previously by our group. In this retrospective review, we looked at 90 males with blast exposure or blunt head trauma suffered in combat and a diagnosis of PTMAD who were placed on Elavil, Verapamil, or Topamax medications for migraine prophylaxis. These patients, while on these medications, actively participated in a vestibular rehabilitation program over a 6–12 week period of time. We compared those individuals at the completion of their rehabilitation to determine the effectiveness of these specific medications on resolution of symptoms and returning to work. Patients were subjected to specific objective neurovestibular tests which included computerized dynamic posturography (CDP), dynamic visual acuity (DVA), and dynamic gait index (DGI).

Results

Comparisons between drug regimens and resolution of symptoms will be discussed.

Conclusion

Although subjectively, physicians have had success in our group on PTMAD, a thorough evaluation of the best medication for this condition and its relationship to expedite recovery has not been characterized. These results will guide selection of migraine prophylactic drug therapy in PTMAD.

Significance

The significance of our study will help guide the treatment of patients with trauma related migraines and dizziness during their rehabilitation.

Support

United States Navy.
R441 – 3D Finite Element Model for Perilymphatic Fistula
Authors: Hayashi Ken , Takuji Koike , Kanzaki Sho , Ogawa Kaoru
Published: August 2008

Problem

To investigate the relationship between the intrusion of the air bubble into the scala vestibli and hearing loss at low frequencies.

Methods

The effect of intrusion of an air bubble into the scala vestibuli on auditory activity was analyzed based on clinical data and using a three‐dimensional finite element (FE) model of the human cochlea. The FE model consists of the stapes, the stapedial annular ligament, the oval window, vestibule, lymph, basilar membrane, osseous spiral lamina, and the cochlear aqueduct. An air bubble in the scala vestibuli was modeled as a small fistula opened on the bony wall of the cochlea. The induced vibration of the lymph and the basilar membrane was calculated by changing the position of the air bubble using CFD‐ACE software.

Results

A traversing wave was generated on the basilar membrane of the intact cochlear model by vibrating the stapes. Even if the air bubble existed in the scala vestibuli, the traversing wave was also generated. When the air bubble existed at the second turn of the cochlea, an envelope of the traversing wave had a notch at the portion where the air bubble existed. The ratio of the maximum amplitude of the basilar membrane in the cochlea with the air bubble to that in the intact cochlea decreased with decreasing frequency. The maximum amplitude of the traversing wave in the cochlea with the air bubble was smaller than that in the intact cochlea by 20 dB at 500 Hz. This result is consistent with clinical data.

Conclusion

Our results suggest that the intrusion of an air bubble into the scala vestibuli causes hearing loss at low frequencies.

Significance

The removal of air bubbles into the scala vestibli is needed for hearing improvement.
R443 – Organotypic Co‐Culture of Spiral Ganglion and Organ of Corti
Authors: Husseman Jacob W , Pak Kwang , Chavez Eduardo , Ryan Allen
Published: August 2008

Problem

The ability to carry out in vitro culture of the auditory neuroepithelium has provided a powerful means of studying inner ear development. Recently, we have developed an organotypic culture technique that mimics the perinatal cochlea in vivo.

Methods

Using sterile microdissection and in vitro methods, we have been able to co‐culture explanted spiral ganglion (SG) with separate explanted organ of Corti (oC) from different neonatal mice. The SG and oC were co‐cultured in their correct anatomical positions. Success of the technique appears dependent on the use of culture plate inserts which prevent cellular attachment to the plastic culture surface and the resulting migration of neurons and hair cells (HCs).

Results

Using this technique, we have noted an average of 5–10 neurites per SG explant growing into the oC via the spiral lamina, following the anatomic pathway used during development. Confocal microscopy was used to visualize the contact area between dendritic growth and HCs. This demonstrates branching of neurites to multiple inner HCs as well as some branches extending to outer HCs. This pattern is consistent with early cochlear development. In contrast, with alternate techniques, neurites followed very different paths to the oC, sometimes innervating inner hair cells from the outer hair cell side of the epithelium.

Conclusion

This culture system offers a unique capacity to evaluate factors affecting spiral ganglion neurite guidance via manipulation of either the oC or SG.

Significance

The use of separated SG and oC will allow tissue from knockout mice to be paired with wild‐type tissue, to explore fundamental mechanisms involved in cochlear innervation. Clinical implications include the ability to optimize SG ingrowth to cochlear implant electrodes offering tremendous potential for improving frequency resolution and dynamic range, as well as the ability to direct SG dendrites to regenerated/transplanted HCs as such advances develop.
R444 – Deposits in Semicircular Canal in Meniere's Disease
Authors: Morita Norimasa , Joglekar Shruti Siddharth , Cureoglu Sebahattin , Kariya Shin , Patricia Schachern , Harada Tamotsu , Paparella Michael M
Published: August 2008

Problem

Positional vertigo is a common complaint in patients with Meniere's disease. Benign paroxysmal positional vertigo has been postulated to be the result of free‐floating degenerative otoconia in the semicircular canal (canalithiasis) or debris that becomes adherent to the cupula (cupulolithiasis). A recent retrospective review of a large population of patients with benign paroxysmal positional veritigo reported a high rate of association of benign paroxysmal positional veritigo and Meniere's disease. The purpose of this study was to investigate the incidence of deposits in the semicircular canals of patients with Meniere's disease compared to their incidence in normal bones.

Methods

Temporal bones included: 22 from 11 patients with bilateral Meniere's disease; 38 temporal bones from 19 patients with unilateral Meniere's disease, and 50 age‐matched normal controls from 30 individuals.

Results

There was a significant difference between normal and diseased temporal bones in the incidence of cupular deposits (p = 0.007 in bilateral and p = 0.01 in Unilateral) and free‐floating deposits (p = 0.007 in bilateral; p = 0.002 in Unilateral) in the posterior semicircular canal. There was no significant difference between normal and diseased temporal bones in the incidence of deposits in other canals.

Conclusion

The higher prevalence of free‐floating degenerative otoconia and cupular deposits in the posterior semicircular canal in Meniere's disease indicates their possible association to benign paroxysmal positional vertigo. Further clinical and pathological studies are required to confirm this association.

Significance

Canalithiasis or cupulolithiasis may be possible causes of benign paroxysmal positional vertigo in patients with Meniere's disease.

Support

International Hearing Foundation, Hubbard Foundation, Starkey Foundation.
R446 – Rostral Cochlear Nucleus Changes After Cochlear Ablation
Authors: Robinson Kyle , Godfrey Donald A , Godfrey Matthew A.
Published: August 2008

Problem

Identification of neurotransmitter concentration changes occurring in the rostral anterior ventral cochlear nucleus (AVCN) following transection of the auditory nerve within the cochlea.

Methods

Chinchillas with cochlear ablations, as well as sham‐lesioned chinchillas, were euthanized at times ranging from 3 to 84 days post ablation. Both temporal bones and brains were saved. Temporal bones were fixed, embedded in paraffin and sectioned to document the completeness of the cochlear lesion. Brain portions containing the cochlear nuclei were frozen‐sectioned, and sections were freeze dried. Freeze‐dried sections were microdissected into samples of AVCN for high performance liquid chromatography (HPLC) assay of 12 amino acid concentrations.

Results

The average concentration of glutamate, the most likely neurotransmitter of auditory nerve fibers, declined in the lesioned‐side rostral AVCN by about 25% at 15 days. This decrease was maintained through 31 days post ablation and became bilateral at 83 days. There was no decrease in the adjacent granular region. Larger lesioned‐side decreases, approaching 50%, were found more caudally in the AVCN at 31 days post ablation. The average concentration of the inhibitory neurotransmitter gamma‐aminobutyric acid (GABA) decreased bilaterally by 15–25% at 3 through 15 days post ablation.

Conclusion

The degeneration of the central portion of the auditory nerve following mechanical ablation of the cochlea is accompanied by decreases of glutamate concentration on the lesioned side but bilateral decreases of GABA in the rostral part of the AVCN. These decreases were smaller than those reported previously for the posteroventral cochlear nucleus (PVCN). However, changes more caudally in AVCN approach those found in PVCN.

Significance

Our results are consistent with other evidence that damage to the cochlea leads to neurotransmitter changes in the central auditory system. The smaller changes in AVCN than in PVCN may correlate with different types of auditory processing in these two regions.

Support

The American Tinnitus Association and the University of Toledo Foundation.
R449 – The Role of DPZF in Inner Ear Development and Function
Authors: Xia Gao
Published: August 2008

Problem

The dendritic cell‐derived BTB/POZ zinc finger (DPZF) protein belongs to the C2H2 zinc finger protein transcription factor family. It is localized on chromosome 3 and widely expressed in hematopoietic tissues, including human dendritic cells (DC), monocytes, B cells and T cells. DPZF null mice (DPZF‐/‐) exhibit a circling phenotype, suggestive of an inner ear defect. Here, we present our work on the role of DPZF in hearing defects.

Methods

We used auditory brainstem responses (ABR) and distortion production otoacoustic emissions (DPOAEs) to test the hearing function of DPZF‐/‐ mice, then gross observation and histopathology analysis including serial sections and scanning electron microscopy were performed to exam the cochlea of DPZF‐/‐ mice.

Results

Auditory brainstem responses (ABR) and distortion production otoacoustic emissions (DPOAEs) showed that DPZF‐/‐mice were completely deaf. Disorganized and fewer hair cells of the Corti organ in DPZF‐/‐ mice were identified by scanning electron microscopy. Besides, although the hair cells of the utricle and saccule were grossly normal, the stereocilia were greatly reduced in number. Further more, lipofuscin was seen in the stria vascularis with the amount of which increased with age.

Conclusion

The impaired hearing and balance function and the morphological abnormalities of inner ears are caused by the deletion of DPZF gene.

Significance

DPZF gene may participates in regulating inner ear development and the DPZF null mice may serve as a new disease model of hearing loss.

Support

This work was supported by the ground of Jiangsu Province Famous Doctor Project(RC2007010).
R452 – Nasopharyngeal Yolk Sac Tumors: A Rare Pediatric Occurrence
Authors: Smith Lorraine M , Osborne Ryan F
Published: August 2008

Problem

To report the rare occurrence of a yolk sac tumor of the nose and nasopharynx presenting as acute sinusitis and bilateral complete blindness.

Methods

The clinical presentation, pathologic features, and management of this 2‐year‐old infant girl is reviewed. We also performed a medical literature search in English using PUBMED and OVID databases. We then analyzed the literature with respect to clinical presentation, manifestations and therapies for other extra‐gonadal yolk sac tumors presenting in the head and neck.

Results

The patient was treated with 4 courses of high dose cis‐platinum, etoposide, bleomycin repeated every 3 weeks along with surgery. She had initial mild improvement in visual perception along with shrinkage of her tumor. The yolk sac malignancies of the head and neck are often, large, aggressive lesions on presentation that once treated have a tendency to recur.

Conclusion

Yolk sac tumors (endodermal sinus tumors) represent 3–5% of pediatric malignancies. They are rare malignancies in the head and neck, of germ cell origin. Successful treatment usually requires a combination of chemotherapy and surgical extirpation followed by postoperative chemotherapy.

Significance

Recurrent sinusitis and nasal obstruction in children should be evaluated carefully and with a high level of suspicion for rare nasal and nasopharyngeal malignancies. Early diagnosis and prompt treatment may alleviate many of the presenting symptoms and prolong life.
R454 – Antibiotic Prophylaxis In Otorhinolaryngology
Authors: Fennessy Brendan
Published: August 2008

Problem

The efficacy of perioperative antimicrobial therapy in reducing the rate of wound infections has been demonstrated in clinical trials. However, their use is not a panacea and their misuse may have considerable implications including the emergence of resistance and the risk of reaction. The aim of this study was to evaluate the prophylactic use of antibiotics in otorhinolaryngological procedures in the perioperative period.

Methods

A prospective audit of 51 patients undergoing twelve different consecutive, non‐day case ENT procedures was undertaken over a 4 week period. Each patient was evaluated from the time of antibiotic commencement through their operative procedure, until the treatment was discontinued.

Results

The mean age of the patients was 32.5 years (range 3 to 80 years), of whom 23 (45%) were male. A total of 34 / 51 (66%) patients were administered 4 different antibiotics, each being prophylactic in nature. Where guidelines existed, the prescribing was non adherent in 86% of cases. The antimicrobial prophylaxis was administered at induction in 20/34 (59%), intraoperatively in 3/34 (9%) and postoperatively in 11/34 (32%) of patients. The intravenous courses prescribed were for a mean of 2.8 doses (range 1 to 15).

Conclusion

This study has demonstrated a lack of adherence to guidelines in the perioperative administration of antimicrobial agent and inappropriate timing of prophylaxis in 41% of prescribing.

Significance

This may have significant economic, infection control and medical implications.
R458 – Drug Delivery to the Sinuses‐ Basics and Aerosol Dynamics
Authors: Schuschnig Uwe , Weigand Ashley Norris , Keller Manfred , Elisabeth Klopfer , Krüner Axel , Luber Martin
Published: August 2008

Problem

Drug delivery to the sinuses via aerosols appears to be a very difficult task, since the paranasal cavities are virtually non‐vented cavities. However, there is a scientifically traceable approach to transport aerosol to the sinuses via pressure differences using so‐called “vibrating” or “sonic” aerosols which suggests that pressure fluctuations increase aerosol diffusion and ventilate dead spaces by flow induction.

Methods

The influence of droplet size, vibration frequency and flow rate on drug delivery to the nasal and paranasal cavities was studied in a human nasal cast model (NC). One ml of a Levofloxacin solution (100 mg/ml) was aerosolized into the NC by a VibrENT prototype nebulizer generating a slow, high density aerosol (MMD = 3.7μm) via a perforated vibrating membrane in connection with an adjustable pulsation source.

Results

Total paranasal cavity deposition was highest (‐20 % of label claim) configured with ostia of 1 and 3 mm in diameter and sinus volumes of 7, 12 and 23 ml when VibrENT was operated at flow rates below 3 1/min and a pulsation frequency of 36 Hz. Delivery efficiency decreased at higher frequencies, higher flow rates and with larger aerosol droplets. Omission of pulsation resulted in no paranasal deposition and a drop in nasal cavity deposition from more than 50% to about 6%. Drug deposition to the sinuses is also significantly (p<0.01) affected by the ostium diameter and sinus volume, being lowest (∼0.2 %) at a large ostium diameter (6 mm) and a low sinus volume (7 ml).

Conclusion

It is possible to deliver aerosol to the sinuses but physical boundary conditions like pulsation frequency, aerosol size and flow rate have to be considered for an efficient transport as well as sinus anatomy. PARI VibrENT addresses these requirements.

Significance

Efficient drug transport to the sinuses enables novel therapeutic approaches.
R459 – Relation Between SPA And Symptoms Of Patients With AR And NP
Authors: Yuqin Deng , Zezhang Tao , Yonggang Kong
Published: August 2008

Problem

The aim of this study was to examine if allergic rhinitis and nasal polyposis are associated with the level of surfactant protein‐A.

Methods

Sinus mucosal biopsies were performed in patients with allergic rhinitis(n=15), nasal polyposis(n=21) and controls(n=10). Immunolocalization of surfactant protein was performed with antibodies to SP‐A using Streptavidin Peroxidase Conjugated Method and indirect immunofluorescence method. Blood serums were obtained from three subjects in each group for enzyme‐linked immunosorbent assay (ELISA) analysis of surfactant protein‐A.

Results

By ELISA, AR (n =15) and NP (n = 21) showed significantly decreased levels of SP‐A when compared with controls (n= 10), although these two groups were not statistically significant. Immunohistochemical investigation showed intense SP‐A staining in the nasal epithelium of each groups, but weak staining in patients with AR and NP.

Conclusion

We report for the first time the expression of SP‐A in both diseased and normal nasal mucosa using the indirect immunofluorescence method. There was an inverse relation between surfactant protein‐A levels and symptoms and signs of rhinitis in patients with AR and NP.

Significance

SP‐A may play a defensive role in the chronic inflammatory diseases of upper airway. Understanding the exact role of SP‐A in the upper airway diseases will help develop novel treatment approaches for sinonasal pathoses.
R461 – Role of the Larynx in the Respiratory Reflex Evoked by CPAP
Authors: Ho Ching ‐ Yin , Tan Ching‐Ting , Wu Meng Chuan
Published: August 2008

Problem

Nasal continuous positive airway pressure (CPAP) is standard treatment of obstructive sleep apnea disease. Previous studies demonstrated that CPAP could induce apneic response. We will investigate the role of temperature and humility in positive continuous pressure flow‐induced apnea in this study.

Methods

Using functionally isolated laryngeal animal modal, 42 adult male Sprague‐Dawley rats were used. Study 1, animals were challenged with long‐time stimulation (1 min) to detect the possibility of adaptation. Study 2, Different condition airflow (25C dry‐25C dry, 25C dry‐25C wet, 25C dry‐37C dry and 25C dry‐37C wet) was delivered to find the role of temperature and humidification in the flow‐induced apneic response of larynx. Apneic index was calculated by prolonged expiratory time/baseline expiratory time.

Results

Laryngeal dry room temperature air exposure could induce apneic response and this response is reproducible and could be eliminated by humidification. In contraction, this apneic response could not be inhibited by increasing temperature.

Conclusion

Laryngeal cold dry air stimulation triggered the apneic response which could be eliminated by humidification but not by heating of air. This result informed us using CPAP with humidified air could decrease the CPAP‐induced apnea.

Significance

Using CPAP with humidified air could decrease the CPAP‐induced apnea and increase the CPAP compliance.

Support

NTUH93S034 by Dr. Tan and NSC 93‐2314‐B‐075‐028 by Dr. Ho.
Czech Social Democracy and its “cohabitation” with the Communist Party: The story of a neglected affair
Authors: Kopeček Lubomír , Pšeja Pavel
Published: August 2008

This article attempts to analyze developments within the Czech Left after 1989. Primarily, the authors focus on two questions: (1) How did the Czech Social Democratic Party (ČSSD) achieve its dominance of the Left? (2)What is the relationship between the Social Democrats and the Communist Party of Bohemia and Moravia (KSČM)? We conclude that the unsuccessful attempt to move the KSČM towards a moderate leftist identity opened up a space in which the Social Democrats could thrive, at the same time gradually assuming a pragmatic approach towards the Communists. Moreover, the ability of Miloš Zeman, the leader of the Social Democrats, to build a clear non-Communist Left alternative to the hegemony of the Right during the 1990s was also very important.
Decoding the morphogenetic evolution of thecate hydroids
Authors: Kosevich I.A.
Published: August 2008

Modular organization of colonial hydroids is based on cyclic morphogenesis during growth of their body. In many thecate hydroids (Hydrozoa: Leptomedusae) the shoots of the colony consist of a few distinct elements and possess complex spatial organization. In most cases, the evolutionary sequence of morphogenetic modifications that led to present-day organization of shoots is obscure and not obvious. One of the approaches that allow getting insight into the morphogenetic evolution in colonial thecate hydroids is to analyse the spectrum of different minor morphotypes presented in the population of the certain species. In our opinion, some rare morphotypes allow understanding and reconstructing the scenario of morphogenetic evolution of species under consideration. We describe the application of such an approach for reconstruction of the morphogenetic evolution of Dynamena pumila (L.) (Sertulariidae) with some additional conclusions.
Ontogenetic niche feeding partitioning in juvenile of white sea catfishGenidens barbusin estuarine environments, southern Brazil
Authors: Mendoza-Carranza Manuel , Vieira João Paes
Published: August 2008

Ontogenetic diet changes (prey species richness and size) in juveniles of white sea catfish(Genidens barbus)were tested in three southern Brazilian estuaries: Mampituba (29°12′S), Tramandaí (30°02′S), Chuí (33°44′S). Cluster analysis revealed that white sea catfish juvenile populations in the three estuaries are composed of two feeding groups. These two feeding groups are coincident with a bimodal size–age distribution of the juveniles of white sea catfish. In small catfish (5 to 10 cm TL) copepods were the most numerous prey (Chuí = 86.66%N, Tramandaí = 85.52%N and Mampituba = 52.34%N). In large catfish (10 to 20 cm TL) the most abundant and frequent prey was fish (Chuí: 73.19%N and 74.56%FO; Tramandaí: 85.92%N and 73.33%FO; Mampituba: 52.34%N and 61.54%FO). The Morisita overlap index among small and large fish was low in all estuaries; high values of Morisita's similarity index were observed among same size catfish groups. In all cases, no differences were observed among prey bio-volume curves of same size predator groups (small, F = 0.41,P = 0.65; large, F = 2.19,P = 0.11). In all estuaries, prey size increased significantly with increasing predator size. The 90th regression quantile estimated with most precision the predator–prey size relationship.
Structural and thermochronological constraints to the evolution of the West Antarctic Rift System in central Victoria Land
Authors: Storti Fabrizio , Balestrieri Maria Laura , Balsamo Fabrizio , Rossetti Federico
Published: August 2008

Uncertainty still persists on the structure and evolution of the West Antarctic Rift System, which is one of the largest extensional provinces on Earth. In this paper, we present results of a combined structural and apatite fission track study of the western shoulder of the rift system, in the western coastal area of the Ross Sea between the Reeves and the Mawson glaciers. Structural data indicate that the onshore fault pattern is dominated by N–S striking right‐lateral strike‐slip to transtensional fault systems and their related subsidiary fault populations in the damage zones. Thermochronological data support a Cenozoic age for these faults and, in particular, the onset of the oblique rifting event at about 50 Ma, in Eocene times. Apatite fission track analyses also suggest the possible occurrence of an older cooling/exhumation event in Cretaceous times. When integrated with the geological and geophysical data sets available in the literature, our structural and thermochronological data provide further support to the interpretation of Cenozoic oblique rifting in the West Antarctic Rift System as induced by the transfer of dextral shear from the mid oceanic ridge in the Southern Ocean, into the Antarctic Plate interior.
Variable crustal structure along the Juan de Fuca Ridge: Influence of on‐axis hot spots and absolute plate motions
Authors: Carbotte Suzanne M. , Nedimović Mladen R. , Canales Juan Pablo , Kent Graham M. , Harding Alistair J. , Marjanović Milena
Published: August 2008

Multichannel seismic and bathymetric data from the Juan de Fuca Ridge (JDFR) provide constraints on axial and ridge flank structure for the past 4–8 Ma within three spreading corridors crossing Cleft, Northern Symmetric, and Endeavour segments. Along‐axis data reveal south‐to‐north gradients in seafloor relief and presence and depth of the crustal magma lens, which indicate a warmer axial regime to the south, both on a regional scale and within individual segments. For young crust, cross‐axis lines reveal differences between segments in Moho two‐way traveltimes of 200–300 ms which indicate 0.5–1 km thicker crust at Endeavour and Cleft compared to Northern Symmetric. Moho traveltime anomalies extend beyond the 5–15 km wide axial high and coincide with distinct plateaus, 32 and 40 km wide and 200–400 m high, found at both segments. On older crust, Moho traveltimes are similar for all three segments (∼2100 ± 100 ms), indicating little difference in average crustal production prior to ∼0.6 and 0.7 Ma. The presence of broad axis‐centered bathymetric plateau with thickened crust at Cleft and Endeavour segments is attributed to recent initiation of ridge axis‐centered melt anomalies associated with the Cobb hot spot and the Heckle melt anomaly. Increased melt supply at Cleft segment upon initiation of Axial Volcano and southward propagation of Endeavour segment during the Brunhes point to rapid southward directed along‐axis channeling of melt anomalies linked to these hot spots. Preferential southward flow of the Cobb and Heckle melt anomalies and the regional‐scale south‐to‐north gradients in ridge structure along the JDFR may reflect influence of the northwesterly absolute motion of the ridge axis on subaxial melt distribution.
Decadal variations of the relationship between the summer North Atlantic Oscillation and middle East Asian air temperature
Authors: Sun Jianqi , Wang Huijun , Yuan Wei
Published: August 2008

The relationship between the summer (July–September) North Atlantic Oscillation (SNAO) and simultaneous East Asian air temperature is investigated. The results show that the SNAO is related to middle East Asian summer air temperature, however this linkage varies with time on decadal timescale: a strong connection appears after the late 1970s but a weak connection before the late 1970s. Further analysis indicates that this instable relationship may have resulted from the shift of the SNAO mode around the late 1970s. In the period of 1979–2003, the centers of the SNAO mode are located more eastward. A positive‐phase (negative‐phase) SNAO produces a strong lower‐level divergence (convergence) over the Asian jet entrance region, in turn stimulates a strong upper‐level convergence (divergence) via the Ekman pumping. Such a convergence (divergence) then excites a zonally oriented quasi‐stationary barotropical Rossby wave train along the Asian upper‐level jet. Thus the SNAO signal is transported eastward to East Asia, resulting in an anomalous summer air temperature over middle East Asia. However, in the period of 1951–1975, the centers of the SNAO mode are located more westward. The associated upper‐level divergence/convergence is away from the Asian jet entrance region, and the SNAO signal cannot be transported eastward to East Asia. Hence the connection is broken.
Quantifying the morphology and growth of levees in aggrading submarine channels
Authors: Straub Kyle M. , Mohrig David
Published: August 2008

Levees are the primary elements of self‐formed submarine channels, yet little is know about their morphodynamics. We present field observations of static levee morphology and stratigraphy in addition to laboratory experiments that link levee morphodynamics to turbidity current flow properties. These observations are used to motivate a levee growth model. Using a three‐dimensional seismic volume, we mapped the depositional patterns associated with a network of submarine channels defined by prominent levees on the continental slope offshore Brunei. Levee taper increases rapidly as channel depth increases from 5 to 50 m and then increases at an ever diminishing rate for channels between 50 and 72 m of depth. A similar relationship between levee taper and channel relief was observed in a set of laboratory experiments. We released turbidity currents into a straight channel positioned within a larger experimental basin. The currents were able to interact with the overbank environment and therefore construct channel bounding levees. We link periods of rapid change in levee growth in our experiments to the vertical structure of suspended sediment in turbidity currents. Our field and laboratory observations suggest that the most important parameters controlling levee morphodynamics are the degree of channel confinement and the vertical structure of suspended‐sediment concentration profiles. Our levee growth model couples a simple advection settling model for currents with a vertical sediment concentration profile defined by the Rouse equation. The model reproduces our field and laboratory observations of levee growth and provide a method to estimate current thickness from levee stratigraphy.
Nocturnal vertical CO2 accumulation in two Amazonian ecosystems
Authors: Acevedo Otávio C. , da Silva R. , Fitzjarrald D. R. , Moraes O. L. L. , Sakai R. K. , Czikowsky M. J.
Published: August 2008

Observations of the nocturnal vertical profile of CO2, specific humidity, temperature, and winds over a forested and a deforested site in the Amazonian region are presented. This study aims to understand better how scalars accumulate vertically at these two distinct sites at night. The measurements also provide an alternate way to determine the nocturnal fluxes under extremely calm conditions that vex the eddy covariance method. A profiling system based on a low‐cost Russian CO2 sensor aboard a tethered balloon, developed for this study, is described. At the deforested site, accumulation of scalars is restricted to a 100‐m thick layer, above which background concentrations of CO2 and specific humidity remain unaffected during the night. Over the forest, most of the scalars accumulate within the canopy. At both sites, accumulation and cooling rates are larger during calm periods near the surface, with the scalars escaping to upper levels during windier episodes. At the deforested site, the surface fluxes estimated from the time change of the profiles are only comparable to those observed at the nearby micrometeorological tower under windier, less stable conditions. On extremely stable nights, CO2 accumulates uniformly throughout the accumulation layer, possibly indicating convergence from the nearby forest toward the deforested region.
Characterization of infrasound from lightning
Authors: Assink J. D. , Evers L. G. , Holleman I. , Paulssen H.
Published: August 2008

During thunderstorm activity in the Netherlands, electromagnetic and infrasonic signals are emitted due to the process of lightning and thunder. It is shown that correlating infrasound detections with results from a electromagnetic lightning detection network is successful up to distances of 50 km from the infrasound array. Infrasound recordings clearly show blastwave characteristics which can be related to cloud‐ground discharges, with a dominant frequency between 1–5 Hz. Amplitude measurements of CG discharges can partly be explained by the beam pattern of a line source with a dominant frequency of 3.9 Hz, up to a distance of 20 km. The ability to measure lightning activity with infrasound arrays has both positive and negative implications for CTBT verification purposes. As a scientific application, lightning studies can benefit from the worldwide infrasound verification system.
Cherenkov radiation of shear Alfvén waves
Authors: Van Compernolle B. , Morales G. J. , Gekelman W.
Published: August 2008

A calculation is presented of the radiation pattern of shear Alfvén waves excited by a burst of charged particles propagating along the confinement magnetic field. The characteristic wake patterns are obtained for the inertial and kinetic regimes of wave propagation. In the inertial regime, the waves are only excited by particles moving slower than the Alfvén speed. The radiated wake exhibits an inverted V-shape due to the backward-wave nature of the modes. In the kinetic regime, particles moving faster as well as slower than the Alfvén speed can radiate propagating modes. The super Alfvénic particles, however, excite modes with relatively short transverse scales. The motorboat type of wake of the kinetic modes is more typical of the Cherenkov process obtained in scalar dielectrics. The predictions are in agreement with experimental observations [B. Van Compernolle et al., Phys. Plasmas 13, 09112 (2006)] and computer simulations [F. S. Tsung et al., Phys. Plasmas 14, 042101 (2007)] in which a burst of fast electrons generated by resonant absorption in a magnetized plasma excites a pulse of large-amplitude Alfvén waves.
MgO-codoping effects on the spectroscopic properties of Er3+-doped LiNbO3
Authors: Li Ai-Hua , Zheng Zhi-Ren , Sun Liang , Lü Qiang , Liu Wei-Long , Wu Wen-Zhi , Yang Yan-Qiang , Lü Tian-Quan
Published: August 2008

Optical absorption, spectrally resolved polarized upconversion fluorescence, and time-resolved luminescence spectra are used to investigate the Er3+ spectroscopic properties in a series of congruent LiNbO3 crystals codoped with Er3+ (1 mol %) and MgO (X mol %, X=0, 2, 4, 6, and 8). The absorption spectra indicate that the transition cross section of Er3+ ions decreases with increasing MgO concentration; it is explained as the improvement of the Er3+-site symmetries. A new Er3+ energy site with low energy, which appears in the long wavelength side of the polarized fluorescence spectra for the samples heavily codoped with MgO, is demonstrated in the time-resolved luminescence spectra. An important finding is that mild codoping with MgO clearly does not facilitate the formation of clustered sites, whereas heavy codoping clearly does facilitate it in Er3+-doped LiNbO3 crystals. These results are important to those who consider the material as a 1.5 μm laser or fiber optical cable.
Calibration of charge state conversion surfaces for neutral particle detectors
Authors: Wahlström P. , Scheer J. A. , Wurz P. , Hertzberg E. , Fuselier S. A.
Published: August 2008

Molecular oxygen and hydrogen ions were scattered off hydrogen terminated diamondlike carbon (DLC) charge state conversion surfaces at incident grazing angles. The energy range of the scattered particles was 390–1000 eV, and the surface roughness of the DLC surface was of the order of 1 Å rms. For all surfaces almost equal angular scattering and negative ion fractions were found within the uncertainties of the measurement. This result supports the fact that charge state conversion with DLC surfaces is a reliable technology for neutral particle sensing instruments. Furthermore, these instruments can work in the laboratory as well as in the harsh environment on board a satellite.The surfaces measured here are used in the IBEX-lo sensor, a neutral particle sensing instrument on the NASA IBEX mission, which is scheduled for launch into orbit around Earth in July 2008.
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single nanowire metal-semiconductor field-effect transistors
Authors: Liu C. , Dai L. , Ma R. M. , Yang W. Q. , Qin G. G.
Published: August 2008

As far as we know, all the single nanowire (NW) metal-semiconductor field-effect transistors (MESFETs) reported are based on n-type NWs. We report MESFETs based on p-type Zn3P2 single NWs in this paper. The p-type Zn3P2 single NW MESFETs operate in the enhancement mode (E-mode). The source-drain current decreases with gate bias (VG) increasing, confirming the p-type conductance of the Zn3P2 NWs. Typically, the p-type Zn3P2 single NW MESFET has an on/off current ratio of 103, a threshold gate voltage of −0.4 V, and a maximum transconductance of 110 nS.
Tribological degradation of fluorocarbon coated silicon microdevice surfaces in normal and sliding contact
Authors: Hook D. Adam , Timpe Shannon J. , Dugger Michael T. , Krim Jacqueline
Published: August 2008

Reported here is a study of the tribological degradation of the contact interface of a fluorocarbon monolayer-coated polycrystalline silicon microdevice. A surface micromachined silicon tribometer is employed to track changes in the adhesion and friction properties during repetitive normal and sliding contacts. Evidence for tribological degradation commences immediately for parallel sliding contact motion, and is slightly delayed in the case of repetitive impact loading normal to the surface. The observed changes in interfacial behavior indicate dramatic changes in the chemical (i.e., surface energy) and physical (i.e., roughness, real contact area, etc.) nature of the contacting surfaces. Results from microscale sliding and impact experiments are interpreted in the light of the primary physical and chemical degradation mechanisms of monolayer-coated silicon microdevices.
Thermal stability and corrosion resistance of the magnetic anisotropy in ultrathin nanopatterned films
Authors: Bisio F. , Moroni R. , Chincarini A. , Canepa M. , Mattera L.
Published: August 2008

We addressed the thermal stability and corrosion resistance of the magnetic anisotropy of surface-step atoms in nanopatterned ultrathin Fe/Ag(001) films. The step-induced anisotropy was remarkably stable, in ultrahigh vacuum, for flashing temperature up to 520 K, but showed no resistance to atmospheric oxidation. Capping the nanopatterned films with ultrathin chromium overlayers allowed to preserve the magnetic anisotropy due to step atoms while extending its thermal stability to above 670 K and greatly enhancing its resistance under oxidizing atmospheric environment.
Investigation on copper phthalocyanine/multiwalled carbon nanotube interface
Authors: Lozzi L. , Santucci S. , Bussolotti F. , La Rosa S.
Published: August 2008

The electronic and structural properties of copper phthalocyanine deposited onto multiwalled carbon nanotubes were studied as a function of the deposition thickness. The valence band and core level spectra were investigated using photoemission spectroscopy. A shift of the organic highest occupied molecular level toward the Fermi level was observed for very thin film, together with a small shift of the nitrogen and copper core level peak positions. Scanning electron microscope images showed the formation of small particles around the nanotubes, forming a thin overlayer decorating the nanotube walls. An x-ray diffraction analysis reported that these particles present both the α and β crystalline phases.
Acoustic-assist effect on magnetic threshold field and twinning-yield stress of Ni–Mn–Ga single crystals
Authors: Techapiesancharoenkij Ratchatee , Simon Jesse , Bono David , Allen Samuel M. , O’Handley Robert C.
Published: August 2008

Ni–Mn–Ga based ferromagnetic shape memory alloys (FSMAs) have been shown to exhibit large magnetic-field-induced strain (MFIS) up to 10% for frequencies up to 1 kHz. However, a magnetic threshold field of 150–300 kA/m is typically required to achieve MFIS, which will require a large electromagnet. The application of a small acoustic signal to the FSMA crystal during MFIS has been shown to reduce the threshold field by up to 80 kA/m and increase the stress and strain outputs. We systematically study the threshold field and the twinning-yield stress of Ni–Mn–Ga single crystals with and without acoustic assist. The acoustic-assist technique helps to reduce the required threshold field and twinning-yield stress of the samples studied here by 60%. The effectiveness of the acoustic assistance in enhancing twin-boundary motion increases with increasing acoustic drive frequency up to a limiting frequency of 2–5 kHz. The magnitude of the acoustic-assist effect appears to be limited by the performance of the piezoelectric stack used in this experiment. The acoustic assistance is a result of a bipolar stress wave that enhances twin-boundary motion in either direction. For a given piezodrive frequency and displacement amplitude, the stress-wave theory provides an estimate of the expected acoustic stress-wave magnitude, and this acoustic stress value is consistent with the observed decrease in twinning-yield stress.