bluuebunny/crossref_metadata_2025 huggingface dataset:
Limits and chances in an unfortunate course of recurrent orbital rhabdomyosarcoma
Authors: Rustemeyer J , Günther L , Junker L
Published: August 2011

Background: Orbital rhabdomyosarcoma (RMS) in childhood has an excellent survival rate after chemotherapy and radiation, and mutilating surgery can often be avoided. Case report: As a rarity we present an unfortunate disease course in a child suffering from orbital embryonal RMS which did not enduringly respond to multimodal therapy including local excision and exenteration orbitae. After short intervals and despite tumor-free margins, orbital RMS recurred twice and led to an extended exenteration orbitae including the bony margins. Because of the lack of standards for adjuvant therapy in cases of recurrences after exenteration orbitae, therapy had to be restricted to a wait- and- see strategy as the only chance of tumor control. Conclusion: Although survival rates of orbital RMS are high, the possibility of recurrence should not be underestimated. In cases of refractory RMS, new concepts are needed to offer further chances for survival. Key words: Orbital rhabdomyosarcoma, recurrence, orbital exenteration DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5279 Nepal J Ophthalmol 2011; 3(2): 202-205
Tuberculous dacryoadenitis in a child
Authors: Chakraborti C , Biswas R , Mondal M , Muknopadhya U , Datta J
Published: August 2011

Background: Orbital tuberculosis is rare even in endemic areas. The disease may involve soft tissue, lacrimal gland, or the periosteum or bones of the orbital wall. Case: We present an Indian girl, who presented with a slowly growing left-sided superotemporal orbital mass, with no significant previous medical history. The swelling turned to an abscess and burst spontaneously giving rise to a discharging sinus. The discharge was negative for any organism on Gram and Giemsa staining. A tuberculin skin test was strongly positive. Incisional biopsy showed caseating granuloma and Langhan’s giant cells suggestive of tubercular aetiology. The patient responded well to tuberculous chemotherapy. Conclusion: Although tuberculous dacryoadenitis is a very rare manifestation of tuberculosis, still the possibility should be entertained in a slowly growing mass of the lacrimal gland, especially in developing countries where the prevalence of tuberculosis is high. Key words: Tuberculosis, lacrimal gland, histopathology DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5281 Nepal J Ophthalmol 2011; 3(2): 210-213
Needle capsulorhexis in intumescent white cataract using slow injecting viscoelastic device through an anterior chamber maintainer
Authors: Rahar S , Sethi H , Sethi H , Gupta VS
Published: August 2011

DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5282Nepal J Ophthalmol 2011; 3(2): 214-215
Management of corneal vascularization
Authors: Chaudhary M
Published: August 2011

DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5284 Nepal J Ophthalmol 2011; 3(2): 218-219
A need for an awareness campaign about nutrition and hygiene while conducting school eye health programs
Authors: Pokharel A
Published: August 2011

DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5285 Nepal J Ophthalmol 2011; 3(2): 220
Recruitment by SDF-1α of CD34-positive cells involved in sciatic nerve regeneration
Authors: Sheu Meei-Ling , Cheng Fu-Chou , Su Hong-Lin , Chen Ying-Ju , Chen Chun-Jung , Chiang Chih-Ming , Chiu Wen-Ta , Sheehan Jason , Pan Hung-Chuan
Published: August 2011

Object

Increased integration of CD34+ cells in injured nerve significantly promotes nerve regeneration, but this effect can be counteracted by limited migration and short survival of CD34+ cells. SDF-1α and its receptor mediate the recruitment of CD34+ cells involved in the repair mechanism of several neurological diseases. In this study, the authors investigate the potentiation of CD34+ cell recruitment triggered by SDF-1α and the involvement of CD34+ cells in peripheral nerve regeneration.

Methods

Peripheral nerve injury was induced in 147 Sprague-Dawley rats by crushing the left sciatic nerve with a vessel clamp. The animals were allocated to 3 groups: Group 1, crush injury (controls); Group 2, crush injury and local application of SDF-1α recombinant proteins; and Group 3, crush injury and local application of SDF-1α antibody. Electrophysiological studies and assessment of regeneration markers were conducted at 4 weeks after injury; neurobehavioral studies were conducted at 1, 2, 3, and 4 weeks after injury. The expression of SDF-1α, accumulation of CD34+ cells, immune cells, and angiogenesis factors in injured nerves were evaluated at 1, 3, 7, 10, 14, 21, and 28 days after injury.

Results

Application of SDF-1α increased the migration of CD34+ cells in vitro, and this effect was dose dependent. Crush injury induced the expression of SDF-1α, with a peak of 10–14 days postinjury, and this increased expression of SDF-1α paralleled the deposition of CD34+ cells, expression of VEGF, and expression of neurofilament. These effects were further enhanced by the administration of SDF-1α recombinant protein and abolished by administration of SDF-1α antibody. Furthermore, these effects were consistent with improvement in measures of neurological function such as sciatic function index, electrophysiological parameters, muscle weight, and myelination of regenerative nerve.

Conclusions

Expression of SDF-1α facilitates recruitment of CD34+ cells in peripheral nerve injury. The increased deposition of CD34+ cells paralleled significant expression of angiogenesis factors and was consistent with improvement of neurological function. Utilization of SDF-1α for enhancing the recruitment of CD34+ cells involved in peripheral nerve regeneration may be considered as an alternative treatment strategy in peripheral nerve disorders.
C5–8 brachial plexus root injury: the “T-1 hand”
Authors: Bertelli Jayme Augusto , Ghizoni Marcos Flávio
Published: August 2011

Object

Classically, C5–7 root injuries of the brachial plexus have been associated with palsies of shoulder abduction/external rotation, elbow flexion/extension, and wrist, thumb, and finger extension. However, current myotome maps generally indicate that C-8 participates in the innervation of thumb and finger extensors. Therefore, the authors have hypothesized that, for palsies of the thumb and finger extensors, the injury should affect the C-5 through C-8 roots.

Methods

The authors tested their hypothesis in 30 patients with upper-type palsies of the brachial plexus. They traced a correlation between clinical findings and root injury, as documented by CT myelography, direct visualization during surgery, and electrophysiological studies.

Results

In C5–8 root injuries, shoulder abduction and external rotation were paralyzed, and in all patients, wrist extensors were paralyzed. However, in 22 of the 30 patients, wrist extension was possible, because of contraction of the extensor digitorum communis and extensor pollicis longus. Wrist flexion and pronation also were preserved. The T-1 root contributed significantly to innervation of the thumb and finger flexors, ensuring 34% grasping and 40% pinch strength relative to the normal side. Hand sensation was largely preserved.

Conclusions

Based on the authors' observations, they suspect that the clinical scenario previously attributed to a C5–7 root injury is, in fact, a C5–8 root injury. The authors propose referring to this partial palsy of the brachial plexus as a “T-1 hand.”
Bipolar duraplasty: a new technique for reducing transcranial cerebral herniation to allow for definitive cranioplasty
Authors: Gordon Chad R. , Swanson Edward W. , Westvik Tormod , Yaremchuk Michael J.
Published: August 2011

Large, full-thickness calvarial defects cause increased brain tissue compliance, often resulting in transient, transcranial herniation in the setting of normotensive intracranial pressures. Cranioplasty serves to protect the cerebrum from external injury, provide an aesthetic contour, and alleviate neurological symptoms. Traditional options for management include head elevation, osmotic diuresis, mild hyperventilation, durotomy with closure following fluid evacuation, expansile cranioplasty, lobectomy, and procedure abortion with prolonged helmet therapy. Patients treated conservatively with helmet therapy commonly are noncompliant and sustain repeated minor trauma to unprotected cerebral contents. Furthermore, recent literature suggests that early cranioplasty may improve outcomes and reduce costs. The authors present a novel solution, bipolar duraplasty, which allows safe, transient reduction of normotensive parenchymal herniation using bipolar electrocautery. The dura of the herniated sac is cauterized using a low-set, bipolar current in a series of sagittal and coronal lines, resulting in immediate contraction and reduction allowing for definitive cranioplasty. This new method was used in a patient with a 30-cm2 frontal bone defect following resection of a right falcine atypical meningioma. In this scenario, bipolar duraplasty was performed free of complication, and the patient has remained asymptomatic and greatly satisfied for 1 year since the procedure. This technique might facilitate earlier cranioplasty, could be applied to a wide range of patients, and may afford better neurological outcomes at a reduced cost.
A General Mathematical Framework for Calculating Systems-Scale Efficiency of Energy Extraction and Conversion: Energy Return on Investment (EROI) and Other Energy Return Ratios
Authors: Brandt Adam R. , Dale Michael
Published: August 2011

The efficiencies of energy extraction and conversion systems are typically expressed using energy return ratios (ERRs) such as the net energy ratio (NER) or energy return on investment (EROI). A lack of a general mathematical framework prevents inter-comparison of NER/EROI estimates between authors: methods used are not standardized, nor is there a framework for succinctly reporting results in a consistent fashion. In this paper we derive normalized mathematical forms of four ERRs for energy extraction and conversion pathways. A bottom-up (process model) formulation is developed for an n-stage energy harvesting and conversion pathway with various system boundaries. Formations with the broadest system boundaries use insights from life cycle analysis to suggest a hybrid process model/economic input output based framework. These models include indirect energy consumption due to external energy inputs and embodied energy in materials. Illustrative example results are given for simple energy extraction and conversion pathways. Lastly, we discuss the limitations of this approach and the intersection of this methodology with “top-down” economic approaches.
Voluntary versus Enforced Team Effort
Authors: Keser Claudia , Montmarquette Claude
Published: August 2011

We present a model where each of two players chooses between remuneration based on either private or team effort. Although at least one of the players has the equilibrium strategy to choose private remuneration, we frequently observe both players to choose team remuneration in a series of laboratory experiments. This allows for high cooperation payoffs but also provides individual free-riding incentives. Due to significant cooperation, we observe that, in team remuneration, participants make higher profits than in private remuneration. We also observe that, when participants are not given the option of private remuneration, they cooperate significantly less.
Estimation of the Effect of Soil Texture on Nitrate-Nitrogen Content in Groundwater Using Optical Remote Sensing
Authors: Witheetrirong Yongyoot , Tripathi Nitin Kumar , Tipdecho Taravudh , Parkpian Preeda
Published: August 2011

The use of chemical fertilizers in Thailand increased exponentially by more than 100-fold from 1961 to 2004. Intensification of agricultural production causes several potential risks to water supplies, especially nitrate-nitrogen (NO3−-N) pollution. Nitrate is considered a potential pollutant because its excess application can move into streams by runoff and into groundwater by leaching. The nitrate concentration in groundwater increases more than 3-fold times after fertilization and it contaminates groundwater as a result of the application of excess fertilizers for a long time. Soil texture refers to the relative proportion of particles of various sizes in a given soil and it affects the water permeability or percolation rate of a soil. Coarser soils have less retention than finer soils, which in the case of NO3−-N allows it to leach into groundwater faster, so there is positive relationship between the percentage of sands and NO3−-N concentration in groundwater wells. This study aimed to estimate the effect of soil texture on NO3−-N content in groundwater. Optical reflectance data obtained by remote sensing was used in this study. Our hypothesis was that the quantity of nitrogen leached into groundwater through loam was higher than through clay. Nakhon Pathom province, Thailand, was selected as a study area where the terrain is mostly represented by a flat topography. It was found that classified LANDSAT images delineated paddy fields as covering 29.4% of the study area, while sugarcane covered 10.4%, and 60.2% was represented by “others”. The reason for this classified landuse was to determine additional factors, such as vegetation, which might directly affect the quantity of NO3−-N in soil. Ideally, bare soil would be used as a test site, but in fact, no such places were available in Thailand. This led to an indirect method to estimate NO3−-N on various soil textures. Through experimentation, it was found that NO3−-N measured through the loam in sugarcane (I = 0.0054, p < 0.05) was lower than clay represented by paddies (I = 0.0305, p < 0.05). This had a significant negative impact on the assumption. According to the research and local statistical data, farmers have always applied an excess quantity of fertilizer on paddy fields. This is the main reason for the higher quantity of NO3−-N found in clay than loam in this study. This case might be an exceptional study in terms of quantity of fertilizers applied to agricultural fields.
Chemical Profile and Biological Potential of Non-Polar Fractions from Centroceras clavulatum (C. Agardh) Montagne (Ceramiales, Rhodophyta)
Authors: Rocha Otávio P. , Felício Rafael De , Rodrigues Ana Helena B. , Ambrósio Daniela L. , Cicarelli Regina Maria B. , Albuquerque Sérgio De , Young Maria Claudia M. , Yokoya Nair S. , Debonsi Hosana M.
Published: August 2011

The present study reports the Gas Chromatography-Mass Spectrometry (GC-MS) evaluation of the hexanes and dichloromethane fractions from extracts of the red alga Centroceras clavulatum (C. Agardh) Montagne. Twenty three compounds were identified, totaling ca. 42% of both fractions (0.18 g mass extract). The main constituents of the fractions were hexadecanoic acid (17.6%) and pentadecanoic acid (15.9%). Several secondary metabolites with interesting biological activity, such as (-)-loliolide, neophytadiene, phytol were identified. In addition, several classes of secondary metabolites, including phenolic compounds (e.g., phenylacetic acid), terpene derivatives, fatty acids, halogenated compound (e.g., 2-chlorocyclohexenol), lignoids, steroids, esters, amides (e.g., hexadecanamide), ketones, carboxylic acids, aldehydes and alcohols were observed. The occurrence of several of these structural classes is described for the first time in this species. The same fractions analyzed by GC-MS, and a separate set of polar fractions, were evaluated against two life cycle stages (epimastigote and trypomastigote forms) of the protozoan Trypanosoma cruzi and against phytopatogenic fungi Cladosporium cladosporiodes and C. sphaerospermum. The dichloromethane fraction was active against both T. cruzi forms (epimastigote IC50 = 19.1 μg.mL−1 and trypomastigote IC50 = 76.2 μg.mL−1). The hexanes and ethyl acetate fractions also displayed activity against both fungi species (200 μg) by TLC-bioautography.
Essential Oil Composition of the Different Parts and In Vitro Shoot Culture of Eryngium planum L.
Authors: Thiem Barbara , Kikowska Małgorzata , Kurowska Anna , Kalemba Danuta
Published: August 2011

The essential oils obtained by hydrodistillation from the different parts (inflorescence, stalk leaves, rosette leaves and root) as well as from in vitro shoot culture of Eryngium planum L. were analyzed by GC-FID-MS in respect to their chemical composition. The different parts of E. planum and in vitro shoots showed different yields. The part with higher amount was the inflorescences, followed by the stalk leaves and in vitro shoots, rosette leaves and finally roots. The essential oils obtained from rosette leaves and in vitro-derived rosettes had totally different composition. Quantitative differences were also found between compounds of intact plant organs. The main components of stalk leaf oil and rosette leaf oil were monoterpene (limonene, α- and β-pinene) and sesquiterpene hydrocarbons. In inflorescence oil cis-chrysanthenyl acetate (43.2%) was accompanied by other esters (propionate, butanoate, hexanoate and octanoate) and numerous oxygenated sesquiterpenes. Root oil and in vitro shoot oil contained mainly (Z)-falcarinol and 2,3,4-trimethylbenzaldehyde. This is the first report on the chemical composition of this species.
Segment-Based Land Cover Mapping of a Suburban Area—Comparison of High-Resolution Remotely Sensed Datasets Using Classification Trees and Test Field Points
Authors: Matikainen Leena , Karila Kirsi
Published: August 2011

In order to better understand and exploit the rich information content of new remotely sensed datasets, there is a need for comparative land cover classification studies. In this study, the automatic classification of a suburban area was investigated by using (1) digital aerial image data; (2) digital aerial image data and laser scanner data; (3) a high-resolution optical QuickBird satellite image; (4) high-resolution airborne synthetic aperture radar (SAR) data; and (5) SAR data and laser scanner data. A segment-based approach was applied. The classification rules for distinguishing buildings, trees, vegetated ground, and non-vegetated ground were created automatically by using permanent test field points in a training area and the classification tree method. The accuracy of the results was evaluated by using test field points in validation areas. The highest overall accuracies were obtained when laser scanner data were used to separate high and low objects: 97% in Test 2, and 82% in Test 5. The overall accuracies in the other tests were 74% (Test 1), 67% (Test 3), and 68% (Test 4). An important contributing factor for the lower accuracy in Tests 3 and 4 was the lower spatial resolution of the datasets. The classification tree method and test field points provided a feasible and automated means of comparing the classifications. The approach is well suited for rapid analyses of new datasets to predict their quality and potential for land cover classification.
Population Structure and Genetic Diversity of the Fusarium graminearum Species Complex
Authors: Wang Jian-Hua , Ndoye Mbacke , Zhang Jing-Bo , Li He-Ping , Liao Yu-Cai
Published: August 2011

The Fusarium graminearum species complex (Fg complex) consists of phylogenetically distinct species some of which cannot be discriminated based on their morphology. Their chemotypes and geographic distributions are dramatically different, and these highlight the challenges that Fusarium head blight (FHB) poses to plant disease specialists and plant breeders, thereby requiring that quarantine officials employ molecular diagnostic tools in their active surveillance programs. Molecular marker technologies play essential roles in species identification of the Fg complex, and they are being used widely to assess the genetic diversity of the clade. The utility, applicability and limitations of molecular methods for assessing the population structure and genetic diversity within the Fg complex are discussed with suitable examples. Knowledge gained from these studies will provide a baseline for monitoring changes in FHB pathogen diversity and mycotoxin potential over time, both of which are critical to the ultimate control and elimination of this economically devastating disease.
Article Commentary: A Structural Frame for Understanding the Role of Thymidine Analogue Resistance Mutations in Resistance to Zidovudine and Other Nucleoside Analogues
Authors: Menéndez-Arias Luis
Published: August 2011

The acquisition of resistance to nucleoside reverse transcriptase inhibitors (NRTIs) can be mediated by amino acid changes at the dNTP binding site that affect the catalytic efficiency of nucleotide analogue incorporation, or by mutations that, in the presence of a pyrophosphate donor, facilitate excision of 3'-terminal chain-terminating inhibitors from blocked primers. These mutations, known as thymidine analogue resistance mutations (TAMs) are M41L, D67N, K70R, L210W, T215F/Y and K219E/Q. Recently published crystal structures of wild-type and TAM-containing HIV-1 reverse transcriptases bound to double-stranded DNA and the excision product, azidothymidine adenosine dinucleoside tetraphosphate have shed light into the molecular mechanism of excision.
Fumonisin B1 and B2 in dry dog food: preliminary study on commercial samples
Authors: Pagliuca G. , Lugoboni B. , Gazzotti T. , Cipollini I. , Zaghini G.
Published: August 2011

A reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the identification and
quantification of fumonisin B1 (FB1) and fumonisin B2 (FB2) in complete and complementary formulations of dry
dog foods has been optimised and validated. The sample preparation consists of an extraction step followed by
immunoaffinity clean-up. Method performance characteristics were evaluated spiking blank samples on multiple
levels in four replicates. The method showed appropriate performance characteristic: good values of recovery
(>95.9%) and precision (RSD <6.8%), as well as satisfying linearity of calibration curves (r2≥0.99). The limit of
quantification (LOQ) and detection (LOD) were 0.100 µg/g and 0.005 µg/g, respectively, both in complete and
complementary dry dog foods and both for FB1 and FB2. This method was applied to 41 commercial samples in
order to test its efficacy and gain some preliminary data about fumonisin contamination in dog food available in
the Italian market. FB1 and FB2 were detected in all samples analysed and, in particular, 63.41% and 56.10% of the
samples showed concentrations above the LOQ of FB1 and FB2, respectively. The levels of contamination quantified
ranged between LOQ and 5.87 µg/g and 2.93 µg/g for FB1 and FB2, respectively. Among the complete dry dog foods,
standard formulations generally showed an average fumonisins contamination higher than premium formulations.
The guidance value of 5 µg/g set by Commission Recommendation 2006/576/EC for the sum of FB1 and FB2 was
exceeded in two samples: one standard complete dry dog food showed a total fumonisin contamination of 5.19 µg/g
and one complementary food a contamination of 8.80 µg/g.
Patterns of Acoustical Activity of Bats Prior to and Following White-Nose Syndrome Occurrence
Authors: Ford W. Mark , Britzke Eric R. , Dobony Christopher A. , Rodrigue Jane L. , Johnson Joshua B.
Published: August 2011

White-nose Syndrome (WNS), a wildlife health concern that has decimated cave-hibernating bat populations in eastern North America since 2006, began affecting source-caves for summer bat populations at Fort Drum, a U.S. Army installation in New York in the winter of 2007–2008. As regional die-offs of bats became evident, and Fort Drum's known populations began showing declines, we examined whether WNS-induced change in abundance patterns and seasonal timing of bat activity could be quantified using acoustical surveys, 2003–2010, at structurally uncluttered riparian–water habitats (i.e., streams, ponds, and wet meadows). As predicted, we observed significant declines in overall summer activity between pre-WNS and post-WNS years for little brown bats Myotis lucifugus, northern bats M. septentrionalis, and Indiana bats M. sodalis. We did not observe any significant change in activity patterns between pre-WNS and post-WNS years for big brown bats Eptesicus fuscus, eastern red bats Lasiurus borealis, or the small number of tri-colored bats Perimyotis subflavus. Activity of silver-haired bats Lasionycteris noctivagans increased from pre-WNS to post-WNS years. Activity levels of hoary bats Lasiurus cinereus significantly declined between pre- and post-WNS years. As a nonhibernating, migratory species, hoary bat declines might be correlated with wind-energy development impacts occurring in the same time frame rather than WNS. Intraseason activity patterns also were affected by WNS, though the results were highly variable among species. Little brown bats showed an overall increase in activity from early to late summer pre-WNS, presumably due to detections of newly volant young added to the local population. However, the opposite occurred post-WNS, indicating that reproduction among surviving little brown bats may be declining. Our data suggest that acoustical monitoring during the summer season can provide insights into species' relative abundance on the landscape as affected by the occurrence of WNS.
CD4+FOXP3+ T Regulatory Cells in Human Autoimmunity: More Than a Numbers Game
Authors: Long S. Alice , Buckner Jane H.
Published: August 2011

Regulatory T cells (Treg) play a dominant role in suppression of autoimmune pathology, as rescue of Treg number and/or function in model systems can both prevent and reverse disease. These findings have generated a series of studies addressing the role of defects in Treg number and function in human autoimmunity. However, demonstrating global defects in Treg of individuals diagnosed with autoimmune diseases has been challenging. These challenges are founded, in part, in the complexity of human autoimmune diseases in which various genetic factors and environmental triggers contribute to disease susceptibility. Moreover, contribution of failed Treg-mediated suppression to pathogenesis can extend to multiple mechanisms. In this article, we discuss what is known with respect to the number and function of CD4+FOXP3+ Treg in human autoimmunity, focusing on representative autoimmunediseases in which there are diverse Treg-mediated defects. We also highlight the need to better understand Treg plasticity and function in the context of autoimmunity.
Agreeable solutions of variational problems
Authors: Zaslavski Alexander J.
Published: August 2011

In this paper we study solutions of infinite horizon variational problems associated with a certain class of integrands. We consider c-optimal solutions, which were introduced and used for models of solid-state physics and in the theory of thermodynamical equilibrium for materials and agreeable solutions introduced for models of economic dynamics. We show that if an integrand possesses an asymptotic turnpike property, then these two optimality notions are equivalent.
On the stabilization and controllability for a third order linear equation
Authors: da Silva Patrícia Nunes , Vasconcellos Carlos Frederico
Published: August 2011

We analyze the stabilization and the exact controllability of a third order linear equation in a bounded interval. That is, we consider the following equation:

iu_t+i\gamma u_x+ \alpha u_{xx} + i\beta u_{xxx} =0,

where

u=u(x,t)

is a complex valued function defined in

(0,L)\times(0,+\infty)

and

\alpha

,

\beta

and

\gamma

are real constants. Using multiplier techniques, HUM method and a special uniform continuation theorem, we prove the exponential decay of the total energy and the boundary exact controllability associated with the above equation. Moreover, we characterize a set of lengths

L

, named

\mathcal{X}

, in which it is possible to find non null solutions for the above equation with constant (in time) energy and we show it depends strongly on the parameters

\alpha

,

\beta

and

\gamma

.
Sums of seventh powers in the polynomial ring $\mathbb{F}_{2^{m}}[T]$
Authors: Car Mireille
Published: August 2011

Let

F

be a finite field with even characteristic and

q\geq16

elements. We study representations of polynomials

P\in F[T]

as sums

P = X_{1}^{7} +\cdots + X_{s}^{7}

.
Minor effect of physical size sorting on iron solubility of transported mineral dust
Authors: Shi Z. B. , Woodhouse M. T. , Carslaw K. S. , Krom M. D. , Mann G. W. , Baker A. R. , Savov I. , Fones G. R. , Brooks B. , Drake N. , Jickells T. D. , Benning L. G.
Published: August 2011

Abstract. Observations show that the fractional solubility of Fe (FS-Fe, percentage of dissolved to total Fe) in dust aerosol increases considerably from 0.1 % in regions of high dust mass concentration to 80 % in remote regions where concentrations are low. Here, we combined laboratory geochemical measurements with global aerosol model simulations to test the hypothesis that the increase in FS-Fe is due to physical size sorting during transport. We determined the FS-Fe and fractional solubility of Al (FS-Al) in size-fractionated dust generated from two representative soil samples collected from known Saharan dust source regions using a customized dust re-suspension and collection system. The results show that the FS-Fe is size-dependent and ranges from 0.1–0.3 % in the coarse size fractions (>1 μm) to ~0.2–0.8 % in the fine size fractions (<1 μm). The FS-Al shows a similar size distribution to that of the FS-Fe. The size-resolved FS-Fe data were then combined with simulated dust mass concentration and size distribution data from a global aerosol model, GLOMAP, to calculate the FS-Fe of dust aerosol over the tropical and subtropical North Atlantic Ocean. We find that the calculated FS-Fe in the dust aerosol increases systematically from ~0.1 % at high dust mass concentrations (e.g., >100 μg m−3) to ~0.2 % at low concentrations (<100 μg m–3) due to physical size sorting (i.e., particle gravitational settling). These values are one to two orders of magnitude smaller than those observed on cruises across the tropical and sub-tropical North Atlantic Ocean under an important pathway of Saharan dust plumes for similar dust mass concentrations. Even when the FS-Fe of sub-micrometer size fractions (0.18–0.32 μm, 0.32–0.56 μm, and 0.56–1.0 μm) in the model is increased by a factor of 10 over the measured values, the calculated FS-Fe of the dust is still more than an order of magnitude lower than that measured in the field. Therefore, the physical sorting of dust particles alone is unlikely to be an important factor in the observed inverse relationship between the FS-Fe and FS-Al and the atmospheric mineral dust mass concentrations. The results suggest that processes such as chemical reactions and/or mixing with combustion particles are the main mechanisms to cause the increased FS-Fe in long-range transported dust aerosols.
Denitrification and polar stratospheric cloud formation during the Arctic winter 2009/2010
Authors: Khosrawi F. , Urban J. , Pitts M. C. , Voelger P. , Achtert P. , Kaphlanov M. , Santee M. L. , Manney G. L. , Murtagh D. , Fricke K.-H.
Published: August 2011

Abstract. The sedimentation of HNO3 containing Polar Stratospheric Cloud (PSC) particles leads to a permanent removal of HNO3 and thus to a denitrification of the stratosphere, an effect which plays an important role in stratospheric ozone depletion. The polar vortex in the Arctic winter 2009/2010 was very cold and stable between end of December and end of January. Strong denitrification between 475 to 525 K was observed in the Arctic in mid of January by the Odin Sub Millimetre Radiometer (Odin/SMR). This was the strongest denitrification that had been observed in the entire Odin/SMR measuring period (2001–2010). Lidar measurements of PSCs were performed in the area of Kiruna, Northern Sweden with the IRF (Institutet för Rymdfysik) lidar and with the Esrange lidar in January 2010. The measurements show that PSCs were present over the area of Kiruna during the entire period of observations. The formation of PSCs during the Arctic winter 2009/2010 is investigated using a microphysical box model. Box model simulations are performed along air parcel trajectories calculated six days backward according to the PSC measurements with the ground-based lidar in the Kiruna area. From the temperature history of the backward trajectories and the box model simulations we find two PSC regions, one over Kiruna according to the measurements made in Kiruna and one north of Scandinavia which is much colder, reaching also temperatures below Tice. Using the box model simulations along backward trajectories together with the observations of Odin/SMR, Aura/MLS (Microwave Limb Sounder), CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) and the ground-based lidar we investigate how and by which type of PSC particles the denitrification that was observed during the Arctic winter 2009/2010 was caused. From our analysis we find that due to an unusually strong synoptic cooling event in mid January, ice particle formation on NAT may be a possible formation mechanism during that particular winter that may have caused the denitrification observed in mid January. In contrast, the denitrification that was observed in the beginning of January could have been caused by the sedimentation of NAT particles that formed on mountain wave ice clouds.
ANISORROPIA: the adjoint of the aerosol thermodynamic model ISORROPIA
Authors: Capps S. L. , Henze D. K. , Hakami A. , Russell A. G. , Nenes A.
Published: August 2011

Abstract. We present the development of ANISORROPIA, the discrete adjoint of the ISORROPIA thermodynamic equilibrium model that treats the Na+-SO42−-HSO4−-NH4+-NO3−-Cl−-H2O aerosol system, and we demonstrate its sensitivity analysis capabilities. ANISORROPIA calculates sensitivities of an inorganic species in aerosol or gas phase with respect to the total concentrations of each species present with only a two-fold increase in computational time over the forward model execution. Due to the highly nonlinear and discontinuous solution surface of ISORROPIA, evaluation of the adjoint required a new, complex-variable version of the the model, which determines first-order sensitivities with machine precision and avoids cancellation errors arising from finite difference calculations. The adjoint is verified over an atmospherically relevant range of concentrations, temperature, and relative humidity. We apply ANISORROPIA to recent field campaign results from Atlanta, GA, USA, and Mexico City, Mexico, to characterize the inorganic aerosol sensitivities of these distinct urban air masses. The variability in the relationship between PM2.5 mass and precursor concentrations shown has important implications for air quality and climate. ANISORROPIA enables efficient elucidation of aerosol concentration dependence on aerosol precursor emissions in the context of atmospheric chemical transport model adjoints.
Discernible rhythm in the spatio/temporal distributions of transatlantic dust
Authors: Ben-Ami Y. , Koren I. , Altaratz O. , Kostinski A. B. , Lehahn Y.
Published: August 2011

Abstract. The differences in North African dust emission regions and transport routes, between the boreal winter and summer are thoroughly documented. Here we re-examine the spatial and temporal characteristics of dust transport over the tropical and subtropical North Atlantic Ocean, using 10 years of satellite data, in order to determine better the different dust transport periods and their characteristics. We see a robust annual triplet: a discernible rhythm of "transatlantic dust weather". The proposed annual partition is composed of two heavy loading periods, associated here with a northern-route period and southern-route period, and one clean, light-loading period, accompanied by unusually low average optical depth of dust. The two dusty periods are quite different in character: their duration, transport routes, characteristic aerosol loading and frequency of pronounced dust episodes. The southern route period lasts about ~4 months, from the end of November to end of March. It is characterized by a relatively steady southern positioning, low frequency of dust events, low background values and high variance in dust loading. The northern-route period lasts ~6.5 months, from the end of March to mid October, and is associated with a steady drift northward of ~0.1 latitude day−1, reaching ~1500 km north of the southern route. The northern period is characterized by higher frequency of dust events, higher (and variable) background and smaller variance in dust loading. It is less episodic than the southern period. Transitions between the periods are brief. Separation between the southern and northern periods is marked by northward latitudinal shift in dust transport and by moderate reduction in the overall dust loading. The second transition between the northern and southern periods commences with an abrupt reduction in dust loading (thereby initiating the clean period) and rapid shift southward of ~0.2 latitude day−1, and 1300 km in total. These rates of northward advance and southern retreat of the dust transport route are in accordance with the simultaneous shift of the Inter Tropical Front. Based on cross-correlation analyses, we attribute the observed rhythm to the contrast between the northwestern and southern Saharan dust source spatial distributions. Despite the vast difference in areas, the Bodélé Depression, located in Chad, appears to modulate transatlantic dust patterns about half the time. The proposed partition captures the essence of transatlantic dust climatology and may, therefore, supply a natural temporal framework for dust analysis via models and observations.
Chemical characterisation of atmospheric aerosols during a 2007 summer field campaign at Brasschaat, Belgium: sources and source processes, time series, diel variations, and temperature dependencies
Authors: Gómez-González Y. , Wang W. , Vermeylen R. , Chi X. , Neirynck J. , Janssens I. A. , Maenhaut W. , Claeys M.
Published: August 2011

Abstract. Measurements of organic marker compounds and inorganic species were performed on PM2.5 aerosols from a Belgian forest site that is severely impacted by urban pollution ("De Inslag", Brasschaat, Belgium) during a 2007 summer period within the framework of the "Formation mechanisms, marker compounds, and source apportionment for biogenic atmospheric aerosols (BIOSOL)" project. The objectives of this study were to determine sources, source processes, time series, and diel variations of the organic species, and to explore the relationships between their concentrations and those of trace gases (O3, NO2, SO2, and CO2) or meteorological parameters (temperature, relative humidity, wind speed, and rain fall). The measured organic species included (i) low-molecular weight (MW) dicarboxylic acids (LMW DCAs), (ii) methanesulfonate (MSA), and (iii) terpenoic acids originating from the oxidation of α-pinene, β-pinene, d-limonene and Δ3-carene, and (iv) organosulfates related to secondary organic aerosol (SOA) from the oxidation of isoprene and α-pinene. The measurements of MSA, the LMW DCAs and selected inorganic species were done with ion chromatography (IC), while those of the terpenoic acids and organosulfates were performed using liquid chromatography with negative ion electrospray ionisation mass spectrometry [LC/(−)ESI-MS]. The organic tracers explained, on average, 5.3 % of the organic carbon (OC), of which 0.7 % was due to MSA, 3.4 % to LMW DCAs, and 1.2 % to organosulfates and terpenoic acids. The highest atmospheric concentrations of most species were observed during the first five days of the campaign, which were characterised by maximum day-time temperatures >22 °C. Most of the terpenoic acids and the organosulfates peaked during day-time, consistent with their photochemical origin, except the MW 295 α-pinene-related nitrooxy organosulfates and the terpenoic acids, cis-pinic, caric, and limonic acid. High concentrations of 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and low concentrations of cis-pinonic acid were noted during the first five days of the campaign, indicative of an aged biogenic aerosol. Several correlations between organic species were very high (r>0.85), high (0.7
Fossil versus contemporary sources of fine elemental and organic carbonaceous particulate matter during the DAURE campaign in Northeast Spain
Authors: Minguillón M. C. , Perron N. , Querol X. , Szidat S. , Fahrni S. M. , Alastuey A. , Jimenez J. L. , Mohr C. , Ortega A. M. , Day D. A. , Lanz V. A. , Wacker L. , Reche C. , Cusack M. , Amato F. , Kiss G. , Hoffer A. , Decesari S. , Moretti F. , Hillamo R. , Teinilä K. , Seco R. , Peñuelas J. , Metzger A. , Schallhart S. , Müller M. , Hansel A. , Burkhart J. F. , Baltensperger U. , Prévôt A. S. H.
Published: August 2011

Abstract. We present results from the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean), with the objective of apportioning the sources of fine carbonaceous aerosols. Submicron fine particulate matter (PM1) samples were collected during February-March 2009 and July 2009 at an urban background site in Barcelona (BCN) and at a forested regional background site in Montseny (MSY). We present radiocarbon (14C) analysis for elemental and organic carbon (EC and OC) and source apportionment for these data. We combine the results with those from component analysis of aerosol mass spectrometer (AMS) measurements, and compare to levoglucosan-based estimates of biomass burning OC, source apportionment of filter data with inorganic+EC+OC speciation, submicron bulk potassium (K) concentrations, and gaseous acetonitrile concentrations. At BCN, 87 % and 91 % of the EC on average, in winter and summer, respectively, had a fossil origin, whereas at MSY these fractions were 66 % and 79 %. The contribution of fossil sources to organic carbon (OC) at BCN was 40 % and 48 %, in winter and summer, respectively, and 31 % and 25 % at MSY. The combination of results obtained using the 14C technique, AMS data, and the correlations between fossil OC and fossil EC imply that the fossil OC at Barcelona is ~65 % primary whereas at MSY the fossil OC is mainly secondary (~85 %). Day-to-day variation in total carbonaceous aerosol loading and the relative contributions of different sources predominantly depended on the meteorological transport conditions. The estimated biogenic secondary OC at MSY only increased by ~40 % compared to the order-of-magnitude increase observed for biogenic volatile organic compounds (VOCs) between winter and summer, which highlights the uncertainties in the estimation of that component. Biomass burning contributions estimated using the 14C technique ranged from similar to higher than when estimated using other techniques, and the different estimations were highly or moderately correlated. Differences can be explained by the contribution of secondary organic matter (not included in the primary biomass burning source estimates), and/or by an overestimation of the biomass burning OC contribution by the 14C technique if the estimated biomass burning EC/OC ratio used for the calculations is too high for this region. Acetonitrile concentrations correlate well with the biomass burning EC determined by 14C. K is a noisy tracer for biomass burning.
Global distributions of C2H6, C2H2, HCN, and PAN retrieved from MIPAS reduced spectral resolution measurements
Authors: Wiegele A. , Glatthor N. , Höpfner M. , Grabowski U. , Kellmann S. , Linden A. , Stiller G. , von Clarmann T.
Published: August 2011

Abstract. Vertical profiles of mixing ratios of C2H6, C2H2, HCN, and PAN were retrieved from MIPAS reduced spectral resolution nominal mode limb emission measurements. The retrieval strategy followed that of the analysis of MIPAS high resolution measurements, with occasional adjustments to cope with the reduced spectral resolution under which MIPAS is operated since 2005. Largest mixing ratios are found in the troposphere, and reach 1.2 ppbv for C2H6, 1 ppbv for HCN, 600 pptv for PAN, and 450 pptv for C2H2. The estimated precision in case of significantly enhanced mixing ratios (including measurement noise and propagation of uncertain parameters randomly varying in the time domain) and altitude resolution are typically 10 %, 3–4.5 km for C2H6, 15 %, 4–6 km for HCN, 6 %, 2.5–3.5 km for PAN, and 7 %, 2.5–4 km for C2H2.
On the unstable mode merging of gravity-inertial waves with Rossby waves
Authors: McKenzie J. F.
Published: August 2011

Abstract. We recapitulate the results of the combined theory of gravity-inertial-Rossby waves in a rotating, stratified atmosphere. The system is shown to exhibit a "local" (JWKB) instability whenever the phase speed of the low-frequency-long wavelength westward propagating Rossby wave exceeds the phase speed ("Kelvin" speed) of the high frequency-short wavelength gravity-inertial wave. This condition ensures that mode merging, leading to instability, takes place in some intermediate band of frequencies and wave numbers. The contention that such an instability is "spurious" is not convincing. The energy source of the instability resides in the background enthalpy which can be released by the action of the gravitational buoyancy force, through the combined wave modes.
Planktonic dinitrogen fixation along a longitudinal gradient across the Mediterranean Sea during the stratified period (BOUM cruise)
Authors: Bonnet S. , Grosso O. , Moutin T.
Published: August 2011

Abstract. This study provides extensive data on planktonic N2 fixation rates across the whole Mediterranean Sea. They show that N2 fixation occurs in Mediterranean waters during the stratification period, with a clear decreasing trend from the oligotrophic western basin (10–76 μmol m−2 d−1) to the ultra oligotrophic eastern basin (0–0.4 μmol m−2 d−1). Highest rates are measured in the less oligotrophic western basin, between the surface and 75 m-depth, where 45 to 75 % of N2 fixation are found within the picoplanktonic fraction (<3 μm). While the biogeochemical impact of N2 fixation in the eastern basin seems negligible, N2 fixation is able to sustain up to 35 % of new primary production during the stratified period in the western basin. These data disagree with indirect estimates of N2 fixation based on geochemical tracers and nutrient budgets, which indicates that N2 fixation increases with increasing N:P ratios and decreasing stable N isotopic signature of particulate organic nitrogen and NO3− from west to east. These results finally point out the need to assess N2 fixation at a higher temporal resolution in order to better understand the diazotrophs' dynamic under contrasted biogeochemical conditions.