bluuebunny/crossref_metadata_2025 huggingface dataset:
R437 – Sonotubometry With Perfect Sequences in Pathologic Ears
Authors: Martino Ercole F. N. Di , Asenov Deyan , Nath Viorel Emanoil , Telle Aulis , Vary Peter
Published: August 2008

Problem

Sonotubometry is a non‐invasive method for the evaluation of Eustachian Tube (ET) function. Perfect Sequences (PSQE) allow monitoring the ET under physiologic conditions in healthy ears. This study investigates the use of this new approach in pathologic ears.

Methods

Forty individuals were examined. Group A: n=20 individuals (40 normal ears). Group B: n= 11 patients (16 ears) with acute/subacute ET dysfunction. Group C: n=9 patients with chronic problems requiring tympanoplasty. Sonotubometry was performed before and after operation. As opening maneuvers, yawning, dry swallowing, water swallowing, and Toynbee were employed.

Results

In group A an ET opening was seen in 77.06% maneuvers and in all patients. The median amplitude (A) of sound increase was 16.64 dB, the duration of the openings (D) was 365 ms. In group B these values were 34.39%, A = 9.27 dB, D=311 ms before and 72.26%, A= 19.51 dB and D=329 ms after operation (myringotomy/tympanostomy). Group C showed openings in 33.83% with A=9.78dB and D=365 ms. There was no significant change after surgery.

Conclusion

The comparison between normal ears and acute ET dysfunction shows sonotubometrical a return of the normal function after operation within a week in most ears. The results demonstrate that the findings occur not only due to an improved sound transmission through the dry middle ear but from a recovering ET. The results in Group C show that the ET dysfunction is chronic.

Significance

Sonotubometry with PSQE is feasible for assessment of ET (dys)function under physiological conditions. It has therefore the potential to open new perspectives on ET monitoring.

Support

Supported by DFG‐grant MA 3917/1‐1.
R442 – Antioxidant Therapy Prevents Presbycusis In C57BL6 mice
Authors: Heman‐Ackah Selena E , Huang Tina C , Juhn Steven K
Published: August 2008

Problem

Presbycusis, or age‐related hearing loss, is characterized by gradual, progressive sensorineural hearing loss which accompanies aging with associated decreased speech recognition in noisy environments, slowed central processing of acoustic stimuli and impaired sound localization. In addition to impairing one's ability to communicate effectively, presbycusis jeopardizes one's autonomy, presents a safety concern and has been correlated with an increased incidence of clinical depression and social withdrawal. By 2025, it is estimated that approximately 25 million Americans will be affected, thus this presents a major public health concern. The purpose of this study is to evaluate the potential of antioxidant therapy, including two novel antioxidants, in the prevention of presbycusis.

Methods

C57BL6 mice were assigned to treatment or control groups. Treatment groups of mice were fed with a combination of two novel antioxidants, L‐cysteine‐glutathione mixed disulfide and ribose cysteine, as well as vitamin B12, folic acid, and ascorbic acid. Auditory brainstem response thresholds were recorded at baseline and on a monthly basis following initiation of treatment.

Results

Threshold shifts were observed according to the established pattern of age related loss associated with C57BL6 mice. Threshold shifts were decreased in the treatment group. Statistically significant differences (p<0.001) in threshold shifts were observed between the treatment and control groups for click stimulus and pure tones at 4, 8, 12, 16 and 32 kHz. The treatment group was found to have a smaller degree of shift in association with aging.

Conclusion

Combination antioxidant therapy effectively decreased threshold shifts on auditory brainstem responses within the established animal model for presbycusis.

Significance

Combination antioxidant therapy may prove a safe and cost‐effective method of preventing presbycusis in our growing elderly population.

Support

American Academy of Otolaryngology – Head and Neck Surgery Foundation Resident Research Grant.
R453 – Cryoballoon Dilation of Tracheal Stenosis
Authors: Wycherly Benjamin , Malekzadeh Sonya , Steehler Matthew Kirk , Kevin Burke , Kallakury Bhaskar
Published: August 2008

Problem

The endoscopic management of tracheal stenosis remains ineffective, despite advances in dilation and resection techniques. The vascular literature reveals improved patency rates of stenosis with cryodilation compared to balloon angioplasty. The proposed mechanism is a decrease in collagen deposition with cryotherapy. Similarly, tracheal cryotherapy maintains the cartilaginous framework of the airway while minimizing collagen deposition. The objective of this study is to compare collagen deposition in tracheal injuries dilated with room temperature versus subfreezing temperature balloons.

Methods

Six New Zealand White rabbits underwent endoscopic tracheal injury with a nylon brush. At 3 weeks post injury, dilation was performed by a balloon inflated with either room temperature saline (n=3), or nitrous oxide to −10 °C, (n=3). Rabbits were sacrificed at 2 and 4 weeks post dilation. Segments of injured trachea were histologically examined for collagen and graded as none, mild, moderate, or severe.

Results

Collagen deposition at 2 weeks post dilation was graded as moderate to severe in all specimens. In the 4 week post dilation tracheas, marked differences in collagen deposition were noted. While the trachea dilated at room temperature was graded as moderate to severe, the cryoballoon dilated trachea showed minimal to no collagen deposition. Despite the observed differences in collagen deposition, sub‐mucosal thickness differed between specimens by an average of 0.2 mm.

Conclusion

This preliminary study suggests that dilation with balloon cryotherapy decreases collagen deposition in the injured airway.

Significance

Long‐term patency of immature tracheal stenosis may be improved with the addition of subfreezing temperatures to endoscopic dilation techniques.

Support

A grant was provided by Boston Scientific, Inc. in the form of money and supplies.
R457 – Paranasal Aerosol Delivery of Budesonide Using PARI VibrENT
Authors: Schuschnig Uwe , Weigand Ashley Norris , Keller Manfred , Krüner Axel , Müller Dominik
Published: August 2008

Problem

Nasal sprays containing inhaled corticosteroids are widely used for the treatment of chronic, allergic and acute sinusitis. However, nasal sprays deposit mainly on the nasal valve and on the anterior portion of the nose, and are rapidly cleared from there. Clinical efficacy data are equivocal which might be caused by the inability of nasal sprays to reach into the posterior regions of the nose. Hence, a drug delivery system such as the PARI VibrENT designed to target the deep nose and the paranasal cavities via a pulsating aerosol may offer substantial benefits.

Methods

Nebulization efficiency was investigated by a novel cast deposition model of the upper airway including paranasal sinuses developed by PARI GmbH (Munich, Germany). 0.5 mL of a captisol enabled budesonide inhalation solution (CBIS, 480 μg Budesonide/ml) was completely aerosolized into each nostril. Consequently, in total 1 ml or 480 μg of Budesonide were administered in about 3 minutes. Sinus deposition was measured by extracting the deposited drug with a defined volume of solvent and assayed by HPLC.

Results

The mean values are as follows: the mean paranasal deposition was 15.9% of the initially charged budesonide amount. Only about 2% of the initial budesonide charge remained in the nebulizer, whereas 57.7% deposited in the nasal cavity, 15.2 % were expelled and 90.8 % of the drug was recovered. Deposition in the single sinus cavities ranged from 0.1% up to 7% depending significantly on sinus volume (p<0.01) and ostium diameter (p<0.01).

Conclusion

Relevant drug amounts could be delivered by the VibrENT into the nose and paranasal cavities of the nasal cast. Sinus deposition depends on its anatomy and was highest with ostium diameters from 1.5 to 3 mm.

Significance

Significant sinus deposition of abudesonide solution may be attainable through the use of the VibrENT nebulizer system. Clinical studies are warranted.
R462 – Anatomic Characteristics of Tongue Coblation
Authors: Delong Liu , Qingfeng Liu , Wenfei Qin
Published: August 2008

Problem

We investigated the topographic anatomic characteristics of the human tongue in order to determine the safest location for Coblation® (ArthroCare Corp., Sunnyvale, CA) tongue treatment in patients with obstructive sleep apnea‐hypopnea syndrome (OSAHS) and to provide detailed anatomic data to facilitate the surgery.

Methods

We dissected 16 lateral tongues from human cadavers and studied the distribution of the hypoglossal nerve and lingual artery and their respective distances. The ratios of those distances to the length and width of the tongue were calculated to establish the safest locations for Coblation tongue treatment.

Results

The vertical distance from the hypoglossal nerve and lingual artery to the surface of the tongue was invariant near the foramen caecum. The ratio of the horizontal distance from the hypoglossal nerve and lingual artery to the midline of the tongue to its length and the vertical distance to the surface at the foramen caecum and at 10 mm and 25 mm from the apex was obtained. Analysis of the data using ANOVA (analysis of variance) revealed statistically significant differences (p<0.05).

Conclusion

Low‐temperature radiofrequency tongue treatment (Coblation) offers a safe and effective treatment for patients with retroglossal OSAHS. Recognizing the topographic anatomic characteristics of the tongue and applying the concepts of ratio and individualization, in which consideration is given to each patient's unique anatomy, promotes greater safety and optimal patient outcomes.

Significance

The data could extend the area of surgery in tongue from before or after caecum to the whole tongue. It could facilitate the coblation tongue treatment which is different from those surgeries in the base of tongue. And coblation tongue channeling (CTC) is very useful to treat hypertrophic tongue in obstructive sleep apnea syndrome (OSAS). We have performed many CTC on the patients with OSAS and give the relative area by proportional view in the tongue based on the data.
An enhanced apoptosis and a reduced angiogenesis are associated with the inhibition of lung colonisation in animals fed ann-3 polyunsaturated fatty acid-rich diet injected with a highly metastatic murine melanoma line
Authors: Mannini Antonella , Kerstin Nadja , Calorini Lido , Mugnai Gabriele , Ruggieri Salvatore
Published: August 2008

Both epidemiological and experimental studies indicate that dietaryn-3 PUFA inhibit carcinogenesis and tumour growth. Metastatic diffusion has also been found to be affected in animals fed diets containing purifiedn-3 PUFA or fish oil. In the present study, we investigated whether the metastatic diffusion of a highly metastatic variant (F10-SR cells) isolated from the B16 melanoma F10 line was affected by feeding host animals a diet containing 5 % fish oil. In these animals, compared with those fed a diet containing 5 % maize oil, there was a reduced number of metastatic pulmonary colonies. The immunohistochemical analysis of appropriate markers revealed that the antimetastatic effect of dietaryn-3 PUFA was not related to a reduction of proliferation, but rather to an enhanced apoptotic activity. The reduction of von Willebrand factor immunoreactivity found in pulmonary colonies of F10-SR cells grown in fish oil-fed animals indicates that a decrease of angiogenesis contributes to the antimetastatic effect of dietaryn-3 PUFA. This conclusion stands in spite of the higher expression of vascular endothelial growth factor observed in pulmonary colonies grown in fish oil-fed animals.
Intramammary infusion of a live culture for treatment of bovine mastitis: effect of live lactococci on the mammary immune response
Authors: Crispie Fiona , Alonso-Gómez Mercedes , O'Loughlin Collette , Klostermann Katja , Flynn James , Arkins Seán , Meaney William , Paul Ross R , Hill Colin
Published: August 2008

In the accompanying article, we demonstrated that a live culture ofLactococcus lactiscompares favourably with antibiotics for treatment of bovine mastitis in two initial field trials. In an effort to explain the mechanism involved, this study investigated the effect of culture administration on the local immune response. In this respect we initially observed that infusion of the live cultureLactococcus lactisstimulated substantial recruitment of polymorphonucleocytes (PMN) and lymphocytes to the udder. For instance, in one assay, quarters infused with the probiotic experienced a dramatic increase (~20 000-fold) in neutrophils over the first 48-h period from an average value of 83·6 cells/ml pre-treatment to 1·78×106 cells/ml 48 h post-infusion. Levels of the acute phase proteins haptaglobin and milk amyloid A were also elevated significantly in comparison with controls following infusion of the culture. The results of flow cytometric assays also demonstrated that while infusion of a live lactococcal culture led to an enhanced recruitment of PMN to the udder (from 1·85×104 cells/ml pre-infusion to 1·45×106 cells/ml 24 h post-infusion) cell-free supernatant from the same culture was not able to do so, indicating that liveLc. lactiscan specifically trigger the mammary immune response to elicit PMN accumulation. These results suggest that the mechanism responsible for this probiotic treatment of mastitis is associated with stimulation of the host intramammary immune system.
The role of native bovine α-lactalbumin in bovine mammary epithelial cell apoptosis and casein expression
Authors: Riley Lisa G , Wynn Peter C , Williamson Peter , Sheehy Paul A
Published: August 2008

Folding variants of α-lactalbumin (α-la) are known to induce cell death in a number of cell types, including mammary epithelial cells (MEC). The native conformation of α-la however has not been observed to exhibit this biological activity. Here we report that native bovine α-la reduced the viability of primary bovine mammary epithelial cells (BMEC) and induced caspase activity in mammospheres, which are alveolar-like structures formed by culturing primary BMEC on extracellular matrix in the presence of lactogenic hormones. These observations suggest a possible role for bovine α-la in involution and/or maintaining the luminal space in mammary alveoli during lactation. In addition, co-incubation of bovine α-la in an in-vitro mammosphere model resulted in decreased β-casein mRNA expression and increased αs1- and κ-casein mRNA expression. This differential effect on casein expression levels is unusual and raises the possibility of manipulating expression levels of individual caseins to alter dairy processing properties. Manipulation of α-la levels could be further investigated for its potential to enhance milk protein expression and/or improve lactational persistency by influencing the balance between proliferation and apoptosis of BMEC, which has a major influence on the milk-producing capacity of the mammary gland.
Heavy metal distribution in two cetacean species from Rio de Janeiro State, south-eastern Brazil
Authors: de Carvalho Carlos Eduardo Veiga , Di Beneditto Ana Paula M. , Souza Cristina Maria M. , Ramos Renata M.A. , Rezende Carlos Eduardo
Published: August 2008

Mercury (Hg), cadmium (Cd) and zinc (Zn) concentration were analysed in muscular and liver tissues of two cetacean species, franciscanaPontoporia blainvilleiand boto-cinzaSotalia guianensis, in order to compare their contamination levels in northern Rio de Janeiro State, south-eastern Brazil. The cutlassfish,Trichiurus lepturus, which is the preferential prey of the boto-cinza, have also been analysed. Liver tissue always presented higher concentrations when compared with muscle samples for all the studied metals. The boto-cinza showed higher concentrations for all metals in both tissues than in the franciscana, and the only exception was Cd. This result is probably related to the difference in size prey preference of each cetacean. Mercury was the only element that presented significant positive correlations with body length and age in both cetacean species. The cutlassfish showed rising Hg concentrations with weight and total length, suggesting a possible mercury pathway for marine mammals' contamination.
Christianity and the ethics of belief
Authors: ZAMULINSKI BRIAN
Published: August 2008

The ethics of belief does not justify condemning all possible forms of religion even in the absence of evidence for any of them or the presence of evidence against all of them. It follows that attacks on religion like the recent one by Richard Dawkins must fail. The reason is not that there is something wrong with the ethics of belief but that Christian faith need not be a matter of beliefs but can instead be a matter of assumptions to which the faithful person is committed. It follows that Christianity can be compatible with scientific rationality.
Robert Boyle on the diversity of religions
Authors: DUMSDAY TRAVIS
Published: August 2008

Robert Boyle's treatise, ‘On the diversity of religions’, remains a little-known work, and was unpublished during his lifetime. Nonetheless it is of considerable historical and philosophical interest. In it, Boyle attempts to answer the question of how one can hope to obtain religious truth amidst the many competing claims to revelation, a concern which had grown acute in the early modern period. In this paper I examine Boyle's arguments, considering along the way their relationship to the various contemporary debates on diversity and evaluating their present relevance.
Forest environmental income in Vietnam: household socioeconomic factors influencing forest use
Authors: MCELWEE PAMELA D.
Published: August 2008

Much research has focused on understanding the importance of forest environmental income in different communities and highlighting key socioeconomic characteristics of forest-dependent households. This paper examines the economic importance of forests among rural agriculturalists in Vietnam. Data were collected through a questionnaire survey of 104 households in five study villages in Ha Tinh province in north central Vietnam surrounding the Ke Go Nature Reserve (KGNR). Variables such as migration status of the household, age, income class and landholdings were used to identify characteristics of households with high forest income in both absolute and relative terms. More than half of households reported receiving forest environmental income in cash. Socioeconomic variables were compared between forest cash income (FCI) households and non-FCI households. Non-FCI households had more alternative income sources from wage labour and livestock, while FCI households were significantly younger, tended to live closer to the forest and had larger landholdings. Contrary to other research on forest use, the households deriving the most forest income in both absolute and relative terms were not the poorer households, but those in the middle class. These findings highlight the need for conservation and development projects to pay attention to the specific household factors that influence forest use, rather than relying on assumptions that poverty and forests are always linked.
Biodiversity in small-scale tropical agroforests: a review of species richness and abundance shifts and the factors influencing them
Authors: SCALES BEN R. , MARSDEN STUART J.
Published: August 2008

Although small-scale agroforestry systems (swiddens, complex and single-crop-dominated agroforests, and homegardens) form a diverse and important tropical land use, there has been no attempt to collate information on their value for biodiversity. This paper reviews 52 published studies that compared species richness and/or abundance between agroforests and primary forest, and 27 studies that compared biodiversity parameters across agroforests. The former covered a broad range of taxa and geographical areas, but few focused on homegardens, while those comparing across agroforestry systems were biased towards studies of plants (21 studies) and homegardens (13 of 27). Of 43 studies comparing species richness or diversity across habitats, 34 reported lower richness in agroforests than in adjacent forest. There was also high β diversity between primary forests and agroforests. Patterns of abundance shifts were less straightforward, with many species traits (for example diets) being generally poor indicators of response to agricultural disturbance. Among the few trends identified, restricted-range or rare species, and terrestrial and some understorey vertebrates tended to decline most, and open country species, granivores and generalists increased most in agroforests. Variability in biodiversity retention across systems has been linked most strongly to economic function, management intensity and extent of remnant forest within the landscape, as well as more subtle cultural influences. Species richness and abundance generally decrease with increasing prevalence of crop species, more intensive management, decreasing stratum richness and shortening of cultivation cycles. Increasing holding size did not necessarily reduce α diversity. Knowledge of the general effects of small-scale agroforestry on biodiversity is substantial, but the great diversity of systems and species responses mean that it is difficult to accurately predict biodiversity losses and gains at a local level. Further work is required on the influence of spatial and temporal structure of agricultural holdings on biodiversity retention across agriculture/succession/forest mosaics, how β diversity across individual holdings influences biodiversity across landscapes, and ultimately on how agricultural intensification can be best managed to minimize future losses of biodiversity from tropical landscapes.
Prevalence and determinants of physical activity and lifestyle in relation to obesity among schoolchildren in Israel
Authors: Nitzan Kaluski Dorit , Demem Mazengia Getachew , Shimony Tal , Goldsmith Rebecca , Berry Elliot M
Published: August 2008

Objective

To describe the relationships between physical activity, lifestyle determinants and obesity in adolescent Israeli schoolchildren.

Design and setting

Cross-sectional survey.

Subjects

The MABAT Youth Survey was a nationally representative, school-based study of youth in grades 7 to 12 (ages 11–19 years).

Methods

Self-administered questionnaires assessed health behaviours and anthropometric indices were measured. Logistic regression analysis was used to examine the associations between obesity, physical activity, socio-economic status and other lifestyle habits. One-way ANOVA was used to determine mean physical activity levels (MET values) by BMI categories.

Results

The prevalence of overweight was 13–15 % and of obesity 4–9 % depending on gender and ethnicity, and was higher among the non-Jewish sectors. Thirty-six per cent and 57 % of Jewish girls and boys, and 40 % and 58 % of non-Jewish girls and boys, respectively, were optimally active. Boys from low socio-economic schools and those who slept for less than 6 h at night were less active. Girls from middle school were found to be 53 % more optimally physically active among Jews, and 89 % more among non-Jews, compared with girls from high school (P= 0·001); girls with less educated parents were also less physically active. No clear relationship was found between the level of obesity and physical activity.

Conclusions

Physical inactivity was strongly related to gender, age, social status, sleeping habits, hookah smoking, and parental educational status. Education and intervention programmes should focus on these risk factors.
Exploring nutrition knowledge and the demographic variation in knowledge levels in an Australian community sample
Authors: Hendrie Gillian Anne , Coveney John , Cox David
Published: August 2008

Objectives

Explore the level of general nutrition knowledge and demographic influences of knowledge levels in a community sample.

Design and setting

A sample of volunteers, recruited from community centres in two suburbs of differing socio-economic status, in Adelaide, South Australia.

Subjects

Two hundred and one people, aged 18 years and older, completed a modified and validated version of the General Nutrition Knowledge Questionnaire (113 items). The questionnaire was self-administered and completed under supervision.

Results

Basic messages about eating more fruit, vegetables and fibre, and less fatty and salty foods were best understood. Confusion was evident with more detailed nutrition information. For example, 90 % of the people were aware of the recommendations to eat more fruit and vegetables, but 56 % and 62 % knew the recommended number of servings of fruit and vegetables, respectively. Descriptive statistics showed significant demographic variation in nutrition knowledge levels; multiple regression analysis confirmed the significant independent effects of gender, age, highest level of education and employment status on nutrition knowledge level (P< 0·01 level). The model accounted for 40 % of the variance in nutrition knowledge scores.

Conclusions

There is demographic variation in nutrition knowledge levels and a broad lack of awareness of some public health nutrition recommendations. Having a detailed understanding of the deficiencies in community knowledge should allow for future nutrition education programmes to target subgroups of the population or particular areas of nutrition education, to more efficiently improve knowledge and influence dietary behaviour.
Interplanetary coronal mass ejections that are undetected by solar coronagraphs
Authors: Howard T. A. , Simnett G. M.
Published: August 2008

From February 2003 to September 2005 the Solar Mass Ejection Imager on the Coriolis spacecraft detected 207 interplanetary coronal mass ejections (ICME) in the inner heliosphere. We have examined the data from the Large Angle Spectroscopic Coronagraph (LASCO) on the SOHO spacecraft for evidence of coronal transient activity that might have been the solar progenitor of the Solar Mass Ejection Imager (SMEI) events, taking into account the projected speed of the SMEI event and its position angle in the plane of the sky. We found a significant number of SMEI events where there is either only a weak or unlikely coronal mass ejection (CME) detected by LASCO or no event at all. A discussion of the effects of projection across large distances on the ICME measurements is made, along with a new technique called the Cube‐Fit procedure that was designed to model the ICME trajectory more accurately than simple linear fits to elongation‐time plots. Of the 207 SMEI events, 189 occurred during periods of full LASCO data coverage. Of these, 32 or 17% were found to have a weak or unlikely LASCO counterpart, and 14 or 7% had no apparent LASCO transient association. Using solar X‐ray, EUV and Hα data we investigated three main physical possibilities for ICME occurrence with no LASCO counterpart: (1) Corotating interaction regions (CIRs), (2) erupting magnetic structures (EMS), and (3) flare blast waves. We find that only one event may possibly be a CIR and that flare blast waves can be ruled out. The most likely phenomenon is investigated and discussed, that of EMS. Here, the transient erupts in the same manner as a typical CME, except that they do not have sufficient mass to be detected by LASCO. As the structure moves outward, it accumulates and concentrates solar wind material until it is bright enough to be detected by SMEI.
Primary production in the Southern Ocean, 1997–2006
Authors: Arrigo Kevin R. , van Dijken Gert L. , Bushinsky Seth
Published: August 2008

Estimates of primary production in the Southern Ocean are difficult to obtain but are essential if we are to understand its role in the global carbon cycle. Here we present a 9‐year time series of daily primary production calculated from remotely sensed ocean color, sea surface temperature, and sea ice concentration using a primary production algorithm parameterized specifically for use in Southern Ocean waters. Results suggest that total annual production in waters south of 50°S averaged 1949 ± 70.1 Tg C a−1 (where a is years) between 1998 and 2006, approximately half that of previous estimates. The large but relatively unproductive pelagic province accounted for ∼90% of Southern Ocean production, while area normalized rates of production were greatest on the much smaller continental shelf (109 g C m−2 a−1). Surprisingly, production in the marginal ice zone was only slightly higher than in the pelagic province. The Ross Sea was the most productive sector of the Southern Ocean (mean = 503 Tg C a−1), followed closely by the Weddell Sea (mean = 477 Tg C a−1). Unlike the Arctic Ocean, there was no secular trend in either sea ice cover or annual primary production in the Southern Ocean during our 9‐year study. Interannual variability in annual production was most closely tied to changes in sea ice cover, although changes in sea surface temperature also played a role. Only 31% of the variation in annual production was explained by the Southern Annular Mode. Annual primary production could increase in the future as stronger winds increase nutrient upwelling.
Primary production in the Arctic Ocean, 1998–2006
Authors: Pabi Sudeshna , van Dijken Gert L. , Arrigo Kevin R.
Published: August 2008

Sea ice in the Arctic Ocean has undergone an unprecedented reduction in area and thickness in the last decade, exposing an ever increasing fraction of the sea surface to solar radiation and increasing the habitat suitable for phytoplankton growth. Here we use a primary production algorithm that utilizes remotely sensed chlorophyll a, sea surface temperature, and sea ice extent data to quantify interannual changes in phytoplankton production in the Arctic Ocean between 1998 and 2006. Our results show that since 1998, open water area in the Arctic has increased at the rate of 0.07 × 106 km2 a−1 (where a is years), with the greatest increases in the Barents, Kara, and Siberian sectors, particularly over the continental shelf. Although pan‐Arctic primary production averaged 419 ± 33 Tg C a−1 during 1998–2006, recent increases in open water area have lead to higher rates of annual production, which reached a 9‐year peak in 2006. Annual production was roughly equally distributed between pelagic waters (less productive but greater area) and waters located over the continental shelf (more productive but smaller area). Interannual differences are most tightly linked to changes in sea ice extent, with changes in sea surface temperature (related to the Arctic Oscillation) and incident irradiance playing minor roles. Estimation of primary production in the Arctic will aid the assessment of air‐sea CO2 fluxes and improve our understanding of the ecological and biogeochemical changes that could take place if ice cover continues to decrease.
Observations of the southern East Madagascar Current and undercurrent and countercurrent system
Authors: Nauw J. J. , van Aken H. M. , Webb A. , Lutjeharms J. R. E. , de Ruijter W. P. M.
Published: August 2008

In April 2001 four hydrographic sections perpendicular to the southern East Madagascar Current were surveyed as part of the Agulhas Current Sources Experiment. Observations with a vessel mounted and a lowered ADCP produced information on the current field while temperature, salinity, oxygen and nutrient data obtained with a CTD‐Rosette system, gave information on the water mass structure of the currents southeast of Madagascar. The peak velocity in the pole‐ward East Madagascar Current through these four sections had a typical magnitude of ∼110 cm/s, while the width of this current was of the order of 120 km. The mean pole‐ward volume transport rate of this current during the survey above the 5°C isotherm was estimated to be 37 ± 10 Sv. On all four sections an undercurrent was observed at intermediate depths below the East Madagascar Current. Its equator‐ward transport rate amounted to 2.8 ± 1.4 Sv. Offshore of the East Madagascar Current the shallow South Indian Ocean Countercurrent was observed. This eastward frontal jet coincided with the barotropic and thermohaline front that separates the saline Subtropical Surface Water from the fresher Tropical Surface Water in the East Madagascar Current. The near‐surface geostrophic flow of the East Madagascar Current, derived from satellite altimetry data from 1992 to 2005, suggests a strong variability of this transport due to eddy variability and interannual changes. The long‐term pole‐ward mean transport of the East Madagascar Current, roughly estimated from those altimetry data amounts to 32 Sv. The upper‐ocean water mass of the East Madagascar Current was very saline in 2001, compared to WOCE surveys from 1995. Comparison of our undercurrent data with those of the WOCE surveys in 1995 confirms that the undercurrent is a recurrent feature. Its water mass properties are relatively saline, due to the presence of water originating from the Red Sea outflow at intermediate levels. The saline water was advected from the Mozambique Channel to the eastern slope of Madagascar.
Multiplatform observations of the seasonal evolution of the Saharan atmospheric boundary layer in Tamanrasset, Algeria, in the framework of the African Monsoon Multidisciplinary Analysis field campaign conducted in 2006
Authors: Cuesta Juan , Edouart Dimitri , Mimouni Mohamed , Flamant Pierre H. , Loth Claude , Gibert Fabien , Marnas Fabien , Bouklila Abdelkrim , Kharef Mohamed , Ouchène Bouziane , Kadi Mohamed , Flamant Cyrille
Published: August 2008

We document the seasonal evolution of the Saharan atmospheric boundary layer (SABL), in terms of vertical structure, diurnal cycle, aerosol content, and cloud cover as well as the surface radiative budget, during 2006, using a mobile multiplatform atmospheric observatory implemented in Tamanrasset (Algeria). Ground‐based remote sensing (both active and passive) and in situ instruments were deployed in the framework of the African Monsoon Multidisciplinary Analysis field experiment and were used in synergy with satellite observations. Observations showed a marked seasonal evolution of the SABL characteristics and a large variability during the West African monsoon onset phase. At the beginning of June, hazy conditions prevailed in a deep SABL (∼5 km). Following this, reduced cloud cover induced by anomalous large‐scale subsidence resulted in high surface insolation which enhanced the convective development of the SABL (∼6 km deep). During that period, the proximity of the Saharan heat low was also favorable to the SABL deepening. In August and September, humidity advected from the south enhanced cloud cover and limited the SABL vertical development (∼3.8 km deep). In the wintertime, weak dry convection and the Hadley cell–related subsidence resulted in high visibility and an extremely shallow SABL (∼500 m deep). Throughout 2006, the aerosol vertical distribution within the SABL was nonuniform, with the majority of coarse particles being located near the surface. The aerosol content over Tamanrasset was influenced by dust transport from a variety of source regions after being lifted through different mechanisms (low‐level jets; cold pools or topographic flows).
Use of vegetation properties from EOS observations for land‐climate modeling in East Africa
Authors: Ge Jianjun , Qi Jiaguo , Lofgren Brent
Published: August 2008

Land use/cover change has been recognized as a key component in global climate change. Information on land surface biophysical properties and climatic variables based on in situ data fail to resolve the fine‐scale variability that exists in many parts of the world, including East Africa. In this study, we used the NASA's Earth Observing System (EOS) products to improve the representation of the land surface in a regional climate model as well as assess the model performance. The Moderate Resolution Imaging Spectroradiometer (MODIS) data of leaf area index (LAI) and vegetation fractional cover (VFC) were directly incorporated in the Regional Atmospheric Modeling System (RAMS). The model was validated in terms of the land surface temperature (LST), utilizing the MODIS LST data from both Terra and Aqua satellites. Compared with the built‐in land surface, the ingested MODIS LAI and VFC greatly improved the spatial and temporal dynamics of vegetation in East Africa. Three experiments were carried out for the year of 2003 to test the impacts of land surface conditions. The results showed that the spatial, seasonal, and diurnal characteristics of the RAMS simulated LST were improved because of MODIS LAI and VFC. Specifically, the Intertropical Convergence Zone (ITCZ)–related migration, bimodal temporal variation, and monthly averaged diurnal cycles of LST were more realistically reproduced. The need to realistically represent the spatial and temporal distribution of vegetation is thus highlighted, and the value of the EOS observations for the land‐climate modeling is demonstrated.
Possible mechanisms for glacial earthquakes
Authors: Tsai Victor C. , Rice James R. , Fahnestock Mark
Published: August 2008

The large glacial earthquakes reported on by Ekström et al. (2003, 2006) and Tsai and Ekström (2007) have previously been evaluated in terms of their seismic characteristics. In this paper we attempt to take constraints such as known glacial ice properties, outlet glacier size, calving style, and meltwater variability to construct a self‐consistent physical model of the glacial earthquake process. Since many glaciological parameters are poorly constrained, we parameterize a number of important processes and estimate a wide range of possible values for some properties. The range of model outputs is thus fairly large, but it is still difficult to match observational constraints under most conditions. We find that only a small class of models is able to satisfy the major observational constraints. These models are characterized by (1) lost basal resistance coupled to viscoelastic deformation with extensive internal crevassing or with low effective elastic modulus and possibly low effective viscosity or (2) by nonequilibrium calving, such as having large icebergs capsize into the glacier front. Although observational constraints cannot definitively rule out any of the proposed classes of mechanisms, the calving model has much stronger support. Fortunately, the various models make different predictions regarding observables that can potentially be measured in the near future.
Observations and stochastic modeling of soil moisture control on evapotranspiration in a Californian oak savanna
Authors: Chen Xingyuan , Rubin Yoram , Ma Siyan , Baldocchi Dennis
Published: August 2008

The study of water exchange between soil, plants, and the atmosphere in response to seasonal or periodic droughts is critical to modeling the hydrologic cycle and biogeochemical processes in water‐controlled ecosystems. An essential step in such studies is to characterize changes in evaporation and transpiration under water stress. The objectives of this study are to investigate how soil moisture controls the evapotranspiration in a Californian oak savanna that experiences seasonal droughts, using multiyear field observations at the daily and stand scale, and to model these controls stochastically. The influence of soil moisture on evapotranspiration at the stand scale is studied using correlations between tower‐based evapotranspiration measurements and representative soil moisture obtained by aggregating point measurements. The observed pattern of this effect is found in agreement with an existing model that features a linear reduction of the evapotranspiration when soil moisture falls below a critical value. The model parameters are inferred using a Bayesian framework, and they are found to vary from year to year because of climate variability. The comparison between various aggregations of soil moisture at the stand scale from point measurements demonstrates that the spatial variability of the soil moisture and the water uptake capacity limited by the root biomass need be taken into account to produce a model that is most resistant to interannual variability. Finally, the parameterized model is used to predict the actual evapotranspiration with uncertainty estimates determined using the joint distribution of the parameters derived from the Bayesian framework. The satisfactory agreement between the predicted and measured evapotranspiration suggests that the calibrated model can be incorporated into water balance studies in the future.
Correlation of secondary organic aerosol with odd oxygen in Mexico City
Authors: Herndon Scott C. , Onasch Timothy B. , Wood Ezra C. , Kroll Jesse H. , Canagaratna Manjula R. , Jayne John T. , Zavala Miguel A. , Knighton W. Berk , Mazzoleni Claudio , Dubey Manvendra K. , Ulbrich Ingrid M. , Jimenez Jose L. , Seila Robert , de Gouw Joost A. , de Foy Benjamin , Fast Jerome , Molina Luisa T. , Kolb Charles E. , Worsnop Douglas R.
Published: August 2008

Photochemically processed urban emissions were characterized at a mountain top location, free from local sources, within the Mexico City Metropolitan Area. Analysis of the Mexico City emission plume demonstrates a strong correlation between secondary organic aerosol and odd oxygen (O3 + NO2). The measured oxygenated‐organic aerosol correlates with odd oxygen measurements with an apparent slope of (104–180) μg m−3 ppmv−1 (STP) and r2 > 0.9. The dependence of the observed proportionality on the gas‐phase hydrocarbon profile is discussed. The observationally‐based correlation between oxygenated organic aerosol mass and odd oxygen may provide insight into poorly understood secondary organic aerosol production mechanisms by leveraging knowledge of gas‐phase ozone production chemistry. These results suggest that global and regional models may be able to use the observed proportionality to estimate SOA as a co‐product of modeled O3 production until more complete models of SOA formation become available.
Meridional winds derived from COSMIC radio occultation measurements
Authors: Luan Xiaoli , Solomon Stanley C.
Published: August 2008

Meridional winds at the magnetic meridian in the upper thermosphere are derived from the peak height and density of the ionospheric F2 layer as retrieved by the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites for 4 months from November 2006 to February 2007. These winds (referred to as COSMIC winds) are first validated by comparison at multiple locations with winds obtained from ground‐based incoherent scatter radar (ISR) and Fabry‐Perot interferometer (FPI) measurements. Then longitudinal variations of these winds are investigated and compared with simulations by the National Center for Atmospheric Research Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (NCAR TIE‐GCM). The results show generally good agreement between COSMIC winds, ground‐based measurements, and the simulations. Significant longitudinal variations are presented in the COSMIC winds. At 40°N (local winter), around midnight the COSMIC winds exhibit stronger and longer‐duration equatorward velocities within 110°W–20°W (large negative magnetic declination sector) than those in other longitudes; during late morning hours the poleward winds show similar longitudinal variations. At 40°S (local summer), during the daytime the poleward winds are stronger within 120°E–110°W (large positive magnetic declination sector) than in 60°W–90°E (large negative magnetic declination sector), while during the nighttime the maximum equatorward winds shifts about 2 h later in 60°W–90°E than in 120°E–110°W. Analysis of the TIE‐GCM simulations suggests that the longitudinal variation of meridional winds is mainly induced by magnetic declination due to the contribution of geographic zonal wind.
Cryogenesis and soil formation along a bioclimate gradient in Arctic North America
Authors: Ping C. L. , Michaelson G. J. , Kimble J. M. , Romanovsky V. E. , Shur Y. L. , Swanson D. K. , Walker D. A.
Published: August 2008

In arctic tundra, cryoturbation resulting from frost heave, cracking, and other cryogenic processes produces patterned ground such as nonsorted circles, stripes, nonsorted polygons, and earth hummocks. We studied cryogenic structures and morphological properties of soils associated with patterned‐ground features along a bioclimate gradient in Arctic Alaska and Canada from north (subzone A) to south (subzone E). Most of these soils have strongly developed cryogenic features, including warped and broken horizons, and organic matter moved into the upper permafrost. The expression of cryoturbation generally increases with the gradient southward. Soil color reflects the lithology of the soil, weathering, and accumulation of organic matter. The organic horizons form around the circles, and gleyed matrix with redoximorphic features develop in the lower active layers due to saturation above the permafrost. Cryostructure development depends more on hydrology controlled by microtopography than position along the gradient. The cryostructures form due to freeze‐thaw cycles and ice lens formation, which include granular, platy, lenticular, reticulate, suspended (ataxitic), ice lens, and ice wedges. On the surface, the density of nonsorted circles reached their maximum in subzones C and D. However, once the vegetation cover was removed, the nonsorted pattern grounds reached their optimum stage and become closed packed in subzone E. Frost heave decreases in the south as the vegetation changes from tussocks to shrub tundra. Cryogenesis is the controlling factor in patterned ground formation resulting in cryoturbated soil profiles, cryostructures, and carbon sequestration in arctic tundra soils.
Envisioning a data reuse registry
Authors: Piwowar Heather , Chapman Wendy
Published: August 2008

Repurposing research data holds many benefits for the advancement of biomedicine, yet is very difficult to measure and evaluate. We propose a data reuse registry to maintain links between primary research datasets and studies that reuse this data. Such a resource could help recognize investigators whose work is reused, illuminate aspects of reusability, and evaluate policies designed to encourage data sharing and reuse.
Gender Related Differences in Paraoxonase 1 Response to High‐fat Diet‐induced Oxidative Stress
Authors: Thomàs‐Moyà Elena , Gómez‐Pérez Yolanda , Fiol Miguel , Gianotti Magdalena , Lladó Isabel , Proenza Ana M.
Published: August 2008

Objective: To evaluate the influence of the pro‐oxidant and proinflammatory state related to dietary obesity on serum paraoxonase 1 (PON1) activity in male and female rats.

Methods and Procedures: Adult Wistar rats of both genders were fed on a high‐fat diet to induce weight gain or standard diet for 14 weeks. Body weight was assessed weekly and food intake fortnightly throughout the dietary treatment. Biometrical parameters and serum lipid profile, glucose, insulin, and adipokine levels were measured. To assess the effect of dietary obesity on oxidative stress, levels of liver and serum thiobarbituric acid reactive substances, liver protein carbonyl groups, liver antioxidant enzymes activities, and serum PON1 activities were measured.

Results: High‐fat diet feeding induced a significant body weight gain in both male and female rats, as well as a reduction of liver antioxidant protection. High‐fat diet increased serum lipid peroxides in male rats and reduced serum PON1 activities and serum apolipoprotein A‐I (apoA‐I) levels in females, although did not alter serum PON1 or apolipoprotein J (apoJ) levels.

Discussion: Our results reveal a gender dimorphism in the high‐fat diet‐induced reduction of serum PON1 activity, which is likely to be related to the greater obese and proinflammatory state achieved in female rats. We suggest that the enhanced oxidative stress caused by dietary increased body weight, on leading to high‐density lipoprotein (HDL), apoA‐I or PON1 oxidation could entail the destabilization of the PON1 association to HDL or a direct inactivation of PON1 enzymatic activity, thus accounting for the decreased serum PON1 activities observed in female rats.