bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Patient Use of Medical Information Affect Physician Practice Incentives to Provide Care?
Authors: Fang Hai , Rizzo John
Published: March 2011

Patients as consumers are assuming a more active role in their medical care decision-making, which has been prompted by better access to medical information. Patient use of medical information may affect physician practice incentives to provide care, which critically depends on the agency relationship between physician and patient. If patient use of medical information improves communication and understanding, physicians may need to spend less time explaining what treatments are needed and convincing patients about the appropriateness of their recommendations, increasing incentives to provide care. If patients use information to demand treatments and procedures that are at odds with what the physician would recommend, this might lead to a contentious relationship, making it more difficult to agree upon any course of treatment. We use the Community Tracking Study (CTS) physician survey data, a nationally representative sample in the United States, to study the effects of more-informed patients on physician incentives to provide care. We estimate ordinary least squares and ordered probit models, and apply instrumental variables method to correct for the potential endogeneity of the measure of more-informed patients. The empirical results indicate that more-informed patients appear to be reducing physician incentives to provide care. This is consistent with the view that patient use of medical information from alternative sources besides their own physician may be interfering with the physician’s ability to provide care.
Associations of Pretransplant Weight and Muscle Mass with Mortality in Renal Transplant Recipients
Authors: Streja Elani , Molnar Miklos Z. , Kovesdy Csaba P. , Bunnapradist Suphamai , Jing Jennie , Nissenson Allen R. , Mucsi Istvan , Danovitch Gabriel M. , Kalantar-Zadeh Kamyar
Published: March 2011

Background and objectives:

The association between pretransplant body composition and posttransplant outcomes in renal transplant recipients is unclear. It was hypothesized that in hemodialysis patients higher muscle mass (represented by higher pretransplant serum creatinine level) and larger body size (represented by higher pretransplant body mass index [BMI]) are associated with better posttransplant outcomes.

Design, setting, participants, & measurements:

Linking 5-year patient data of a large dialysis organization (DaVita) to the Scientific Registry of Transplant Recipients, 10,090 hemodialysis patients were identified who underwent kidney transplantation from July 2001 to June 2007. Cox regression hazard ratios and 95% confidence intervals of death and/or graft failure were estimated.

Results:

Patients were 49 ± 13 years old and included 49% women, 45% diabetics, and 27% African Americans. In Cox models adjusted for case-mix, nutrition-inflammation complex, and transplant-related covariates, the 3-month-averaged postdialysis weight-based pretransplant BMI of 20 to <22 and < 20 kg/m2, compared with 22 to <25 kg/m2, showed a nonsignificant trend toward higher combined posttransplant mortality or graft failure, and even weaker associations existed for BMI ≥ 25 kg/m2. Compared with pretransplant 3-month- averaged serum creatinine of 8 to <10 mg/dl, there was 2.2-fold higher risk of combined death or graft failure with serum creatinine <4 mg/dl, whereas creatinine ≥14 mg/dl exhibited 22% better graft and patient survival.

Conclusions:

Pretransplant obesity does not appear to be associated with poor posttransplant outcomes. Larger pretransplant muscle mass, reflected by higher pretransplant serum creatinine level, is associated with greater posttransplant graft and patient survival.
Non-compaction and polyneuropathy in a patient homozygous for the H63D HFE gene mutation
Authors: Stöllberger Claudia , Finsterer Josef
Published: March 2011

Left ventricular hypertrabeculation/non-compaction (LVHT) is a cardiac abnormality that is increasingly reported with an association to several genetic disorders. We report an association of LVHT with genetically confirmed hemochromatosis and polyneuropathy in a 54-year old Caucasian female.
Rare case of a massive buccal mucocele
Authors: Koszowski Rafał , Waśkowska Jadwiga , Morawiec Tadeusz , Wojcik Sylwia , Stęplewska Katarzyna
Published: March 2011

Mucoceles are common pathological lesions of the oral cavity, usually measuring up to 10 mm. The authors describe a case of deeply located buccal mucocele measuring 35 mm in diameter. The lesion was caused by facial injury in a 54-year old man. The lesion persisted for approximately 2.5 years and was difficult to diagnose because of its unusual size and atypical clinical symptoms. Preoperative ultrasonography excluded a tumor, and this was confirmed by histopathological examination. However, oncological alertness was considered necessary on account of ulcerated mucosa next to the lesion. The mucocele was removed through surgical excision, using a scalpel and tissue scissors. No recurrence was observed in 2.5 postoperative years. It is stressed that histopathological examinations help to differentiate mucoceles from other disease processes.
Risk factors for recurrent laryngeal nerve palsy after thyroidectomy
Authors: Čelakovský Petr , Vokurka Jan , Školoudík Lukáš , Kordač Petr , Čermáková Eva
Published: March 2011

This study investigates the incidence of temporary and permanent recurrent laryngeal nerve palsy (RLNP) and possible risk factors for patients with different types of thyroid gland diseases. 1224 consecutive patients who underwent thyroidectomy for treatment of various thyroid diseases between the years 2001–2005. The rates of RLNP were evaluated. The surgeon and type of thyroid gland disorder were recognised as possible risk factors for RLNP. The incidence of temporary/permanent RLNP for the whole group was 4.5/0.8%. The rates of temporary RLNP for groups, classified as multinodular goitre, Graves’ disease, thyroid cancer or Hashimoto’s disease were 4.3%, 4.3%, 5.2% and 5.7%, respectively. The rates of permanent RLNP for the same groups were 0.4%, 0.9%, 1.6% and 1.9%, respectively. The frequency of temporary RLNP for individual surgeons ranges from 2.8 to 7.0% and the rates of permanent RLNP is between 0–3.1%. There was no relationship between the surgeon’s experience (the number of procedures performed) and RLNP rates. Total thyroidectomy is a safe procedure associated with a low incidence of RLNP not only for benign multinodular goitre, but also for Graves’disease, thyroid cancer and Hashimoto’s disease. The rates of RLNP among individual surgeons are acceptable with small inter-individual differences.
Incidence, timing, and treatment of new brain metastases after Gamma Knife surgery for limited brain disease: the case for reducing the use of whole-brain radiation therapy
Authors: Rush Stephen , Elliott Robert E. , Morsi Amr , Mehta Nisha , Spriet Jeri , Narayana Ashwatha , Donahue Bernadine , Parker Erik C. , Golfinos John G.
Published: March 2011

Object

In this paper, the authors' goal was to analyze the incidence, timing, and treatment of new metastases following initial treatment with 20-Gy Gamma Knife surgery (GKS) alone in patients with limited brain metastases without whole-brain radiation therapy (WBRT).

Methods

A retrospective analysis of 114 consecutive adults (75 women and 34 men; median age 61 years) with KPS scores of 60 or higher who received GKS for 1–3 brain metastases ≤ 2 cm was performed (median lesion volume 0.35 cm3). Five patients lacking follow-up data were excluded from analysis. After treatment, patients underwent MR imaging at 6 weeks and every 3 months thereafter. New metastases were preferentially treated with additional GKS. Indications for WBRT included development of numerous metastases, leptomeningeal disease, or diffuse surgical-site recurrence.

Results

The median overall survival from GKS was 13.8 months. Excluding the 3 patients who died before follow-up imaging, 12 patients (11.3%) experienced local failure at a median of 7.4 months. Fifty-three patients (50%) developed new metastases at a median of 5 months. Six (7%) of 86 instances of new lesions were symptomatic. Most patients (67%) with distant failures were successfully treated using salvage GKS alone. Whole-brain radiotherapy was indicated in 20 patients (18.3%). Thirteen patients (11.9%) died of neurological disease.

Conclusions

For patients with limited brain metastases and functional independence, 20-Gy GKS provides excellent disease control and high-functioning survival with minimal morbidity. New metastases developed in almost 50% of patients, but additional GKS was extremely effective in controlling disease. Using our algorithm, fewer than 20% of patients required WBRT, and only 12% died of progressive intracranial disease.
Difficulties with the neurological assessment of humans following a chimpanzee attack
Authors: Khalil Amer , Spiotta Alejandro M. , Barnett Gene H.
Published: March 2011

Chimpanzee attacks can be vicious, mutilating, and disabling if not fatal. Stereotypically, the hands and face are targeted, and in male victims, genitalia are mutilated. The authors present a case highlighting the difficulties with early neurological assessment following such an attack. This 55-year-old woman was attacked by a 14-year-old chimpanzee. She suffered mutilation of both hands, severe midface bony, soft-tissue, and eye injuries, and scalp degloving. An emergency tracheotomy was performed at the scene, with an unclear duration of hypoxia. The patient was unresponsive without spontaneous movements, papillary or corneal reflexes, cough, or gag. Attempts to lighten sedation were not tolerated. Brain CTs were normal. Intracranial pressure monitoring was deemed infeasible. Brain MR imaging suggested diffuse axonal injury consistent with severe shaking trauma. Diffusion tensor imaging indicated intact corticospinal tracts, confirmed by somatosensory evoked potentials. Magnetic resonance imaging suggested left optic nerve transaction, and right retinal detachment was diagnosed. Electroencephalography showed severe diffuse encephalopathy. Auditory evoked potentials showed absent auditory pathway responses except for a right delayed wave V. Visual evoked potentials indicated absent visual function. At 1 month after the attack, sedation and analgesia weaning revealed lower-extremity movement to command, but no upper-limb response. Cervical spine and brachial plexus MR imaging showed brachial plexus edema. Two months after the attack, the patient regained strength in all her extremities and verbally communicated using a Passy-Muir tracheostomy valve. Chimpanzee attacks on humans can cause extensive, life-threatening injuries. The neurological assessment of such patients is challenging, complicated by limb and craniofacial disfigurement and the need for heavy sedation. Initial assessment of nervous system integrity may rely on costly imaging and electrophysiological studies.
Obesity in the north of Iran (South-East of the Caspian Sea)
Authors: Veghari Gholamreza , Joshaghani Hamidreza , Niknezhad Farhad , Sedaghat Mehdi , Hoseini Ahmad , Angizeh Abdolhamid , Tazik Ebrahim , Moharloei Pooneh
Published: March 2011

DOI: 10.3329/bmrcb.v36i3.6167Bangladesh Med Res Counc Bull 2010; 36: 100-101
Surgical management of ventricular septal defect with pulmonary stenosis with idiopathic thrombocytopenic purpura
Authors: Paul Shimu , Uddin Jalal , Ahmed Niaz , Islam Md Sirajul , Millat MH
Published: March 2011

Patients with idiopathic thrombocytopenic pupura (ITP), when under goes any cardiac surgery face an increased risk of postoperative haemorrhagic complications. A 28 years old female patient with idiopathic thrombocytopenic purpura(ITP) and Ventricular septal defect (VSD) with pulmonary stenosis (PS) was operated. We treated her with oral steroid for three weeks immediately before surgery. During surgery under extracorporeal circulation bleeding was controlled meticulously and she was administered methyl prednisolone, injection hydrocortisone, fresh frozen plasma, platelets and whole blood. Steroid was continued postoperatively for two weeks. She did not suffer from any haemorrhagic complication and her recovery was uneventful. Congenital heart disease with idiopathic thrombocytopenic purpura can be operated for heart surgery if appropriate pre, intra and postoperative measures are taken. DOI: 10.3329/bmrcb.v36i3.6665Bangladesh Med Res Counc Bull 2010; 36: 101-103
Effect of single dose intravenous zoledronic acid on bone mineral density in post-menopausal osteoporosis of Bangladeshi women
Authors: Hossain M , Chowdhury IH , Emran MA , Habib AHMA , Asaduzzaman AKM , Alam M , Ferdous C
Published: March 2011

The osteoporosis is a major health threat that affects every third post-menopausal women. Postmenopausal osteoporosis is complicated with vertebral, femoral or radius fracture. This prospective study on post-menopausal osteoporosis was carried out in the Pain Centre, Department of Anaesthesia, Analgesia and Intensive Care Medicine of BSMMU, Dhaka during the period of January 2008 to January 2010. The post-menopausal women with back pain were screened by spinal radiographs and dual-energy X-ray absorptiometry (DXA) of lumbar spine to determine the bone mineral density (BMD). The woman after menopause with a BMD T-score of -2.5 or less with or without evidence of vertebral fracture is considered as post-menopausal osteoporosis. A total of 55 post-menopausal osteoporotic patients were assigned to receive a single dose of IV infusion of zoledronic acid (5mg) along with dietary calcium and vitamin-D. The spinal radiographs and dual-energy X-ray absorptiometry (DXA) were repeated in all the 55 patients at 12 months following zoledronic acid infusion. The mean BMD of lumbar spine increased significantly from pre-infusion value of 0.75695g/cm2 to post-infusion of 0.80216 g/cm2. The T-score also increased from pre infusion value of -3.567±0.77 to -3.158±0.08 in 12 months following the infusion (P<0.01). The increase is 5.026% higher than pre infusion values. The spinal radiographs taken before infusion of zoledronic acid, showed 14 fractures. There was no new fracture in any case during the 12 months study period. So, it can be concluded that once yearly IV infusion of zoledronic acid is associated with a significant increase in BMD and decrease in the risk of vertebral fracture. DOI: 10.3329/bmrcb.v36i3.7285Bangladesh Med Res Counc Bull 2010; 36: 74 -77
Chaperoning Roles of Macromolecules Interacting with Proteins in Vivo
Authors: Choi Seong Il , Lim Keo-Heun , Seong Baik L.
Published: March 2011

The principles obtained from studies on molecular chaperones have provided explanations for the assisted protein folding in vivo. However, the majority of proteins can fold without the assistance of the known molecular chaperones, and little attention has been paid to the potential chaperoning roles of other macromolecules. During protein biogenesis and folding, newly synthesized polypeptide chains interact with a variety of macromolecules, including ribosomes, RNAs, cytoskeleton, lipid bilayer, proteolytic system, etc. In general, the hydrophobic interactions between molecular chaperones and their substrates have been widely believed to be mainly responsible for the substrate stabilization against aggregation. Emerging evidence now indicates that other features of macromolecules such as their surface charges, probably resulting in electrostatic repulsions, and steric hindrance, could play a key role in the stabilization of their linked proteins against aggregation. Such stabilizing mechanisms are expected to give new insights into our understanding of the chaperoning functions for de novo protein folding. In this review, we will discuss the possible chaperoning roles of these macromolecules in de novo folding, based on their charge and steric features.
Using Converter Dust to Produce Low Cost Cementitious Composites by in situ Carbon Nanotube and Nanofiber Synthesis
Authors: Ludvig Péter , Calixto José M. , Ladeira Luiz O. , Gaspar Ivan C.P.
Published: March 2011

Carbon nanotubes (CNTs) and nanofibers (CNFs) were synthesized on clinker and silica fume particles in order to create a low cost cementitious nanostructured material. The synthesis was carried out by an in situ chemical vapor deposition (CVD) process using converter dust, an industrial byproduct, as iron precursor. The use of these materials reduces the cost, with the objective of application in large-scale nanostructured cement production. The resulting products were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) and were found to be polydisperse in size and to have defective microstructure. Some enhancement in the mechanical behavior of cement mortars was observed due to the addition of these nano-size materials. The contribution of these CNTs/CNFs to the mechanical strength of mortar specimens is similar to that of high quality CNTs incorporated in mortars by physical mixture.
LC/MS Guided Isolation of Alkaloids from Lotus Leaves by pH-Zone-Refining Counter-Current Chromatography
Authors: Xu Xia , Sun Cui-Rong , Dai Xiao-Jing , Hu Rui-Lin , Pan Yuan-Jiang , Yang Zhang-Fa
Published: March 2011

The traditional methods used in natural product separation primarily target the major components and the minor components may thus be lost during the separation procedure. Consequently, it’s necessary to develop efficient methods for the preparative separation and purification of relatively minor bioactive components. In this paper, a LC/MS method was applied to guide the separation of crude extract of lotus (Nelumbo nucifera Gaertn.) leaves whereby a minor component was identified in the LC/MS analysis. Afterwards, an optimized pH-zone-refining CCC method was performed to isolate this product, identified as N-demethylarmepavine. The separation procedure was carried out with a biphasic solvent system composed of hexane-ethyl acetate-methyl alcohol-water (1:6:1:6, v/v) with triethylamine (10 mM) added to the upper organic phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase eluent. Two structurally similar compounds – nuciferine and roemerine – were also obtained from the crude lotus leaves extract. In total 500 mg of crude extract furnished 7.4 mg of N-demethylarmepavine, 45.3 mg of nuciferine and 26.6 mg of roemerine with purities of 90%, 92% and 96%, respectively. Their structures were further identified by HPLC/ESI-MSn, FTICR/MS and the comparison with reference compounds.
A Compatible Control Algorithm for Greenhouse Environment Control Based on MOCC Strategy
Authors: Hu Haigen , Xu Lihong , Zhu Bingkun , Wei Ruihua
Published: March 2011

Conventional methods used for solving greenhouse environment multi-objective conflict control problems lay excessive emphasis on control performance and have inadequate consideration for both energy consumption and special requirements for plant growth. The resulting solution will cause higher energy cost. However, during the long period of work and practice, we find that it may be more reasonable to adopt interval or region control objectives instead of point control objectives. In this paper, we propose a modified compatible control algorithm, and employ Multi-Objective Compatible Control (MOCC) strategy and an extant greenhouse model to achieve greenhouse climate control based on feedback control architecture. A series of simulation experiments through various comparative studies are presented to validate the feasibility of the proposed algorithm. The results are encouraging and suggest the energy-saving application to real-world engineering problems in greenhouse production. It may be valuable and helpful to formulate environmental control strategies, and to achieve high control precision and low energy cost for real-world engineering application in greenhouse production. Moreover, the proposed approach has also potential to be useful for other practical control optimization problems with the features like the greenhouse environment control system.
Ageing and disability in the British countryside. A perspective from the North Cotswolds
Authors: Gant Robert
Published: March 2011

Space, location and physical environment are now recognised as significant influences on the life-style and mobility patterns of elderly and disabled people. In sparsely populated rural areas like the North Cotswolds in the West of England the significance of demographic trends for the delivery of social services has been heightened by the implementation of the National Health Service and Community Care Act 1900. This paper focuses on the role of home- and community -based telecommunication services in sustaining the independence of these vulnerable groups. It evaluates four models of telecommunication support : 'telephone trees' ; community alarm systems ; telecottages ; and electronic mail systems. These are discussed with regard to client need and community setting.
Les précipitations intenses en Bretagne
Authors: Dubreuil Vincent , Huon Florence , Lejeune Claire
Published: March 2011

The study of heavy rains (more than 20 mm per a day) for two stations in Brittany (Brest and Rennes) shows important differences between monthly repartition and recent evolution. For Brest, heavy rains occur more frequently in winter and in Rennes it appears more often in summer. But, since 1970, the volume given by those heavy rains increases in Rennes while it seems to be stable in Brest. As the number of days of thunderstorms is not increasing, it could mean that precipitations are locally intensified by regional landuse and landcover. In fact it could be the result of the recent extension of urban areas, of maize and the elimination of hedges in the basin of Rennes.
Les mutations récentes d'un groupe agro-alimentaire breton (Even)
Authors: Calvez Eugene , Piriou Nicole
Published: March 2011

Après une croissance exceptionnelle (1960-1984), la firme laitière coopérative de Ploudaniel (Finistère), a dû entamer, quand survinrent les quotas laitiers, une politique de diversification. Elle le fit à partir de trois choix successifs de stratégie. Actuellement, elle se repositionne sur ses métiers de base, lait et viande.
Un bilan incertain : les variations démographiques et sociales des villes moyennes des Pays de la Loire
Authors: Pihet Christian
Published: March 2011

L'analyse du dernier recensement fait ressortir pour les villes moyennes l'arrêt de leur croissance démographique ainsi qu 'une émigration de jeunes actifs. Dans le même temps les sociétés locales se diversifient. Les progrès de la tertiarisation, mis en avant par les stratégies de développement, s'efforcent de renouveler le tissu économique local.
La ville moyenne : mythe ou réalité ?
Authors: Toinard Stéphane
Published: March 2011

The middle - sized city is being re-discovered. Its role as great animator in rural space, as a driving power within a district is all over being acknowledged. Therefore, what does this concept of « middle - sized city » really means ? What's hidden behind this adjective ? Is this concept - with a somehow « pejorative » meaning - the result of particular cities which have definite goals and duties, or is it - on the contrary - a label, a positive image in term of communication ?
Le rôle de l'industrie dans les villes moyennes de Bretagne
Authors: Philipponneau Michel
Published: March 2011

Within the last forty years, the comparison, in 40 Breton towns, of the situation of industry and the prospects of industrial locations, shows that the « Breton industrial Model » has magnified its scattered characteristics. New industrial implants should even more reinforce the development of medium-sized towns, which is the essential element of a fair regional balance in a still dense rural environment.
La constitution d'un ville-pays : à partir de la région Centre-Portugal
Authors: Beauchard Jacques
Published: March 2011

A partir des routes qui entraînent les populations de Beiras à descendre vers les petites villes du littoral du Centre Portugal et de l'autoroute Nord-Sud, axe central des flux, il s 'agit de repenser, voire de réinventer, le maillage polycentrique des lieux urbains suivant l'unité nouvelle d'une Ville-Pays en formation.
Angoulême, carrefour des influences poitevine et bordelaise
Authors: Hellier Emmanuelle
Published: March 2011

Charente department's capital, with about 100 000 people, Angoulême shows the typical profile of a « big » medium-sized town. Angoulême is the center of a life's region the extension of which nearly covers the department but is depends on big external towns for rare services : Paris of course, but Poitiers and Bordeaux as well, on a regional scale : they are easily accessible by road or by train (high speed train Paris-Bordeaux). Now, administrative regional capital for Angoulême, Poitiers doesn't appear like a métropolitain relay for Angoulême, which turns itself more spontaneously towards Bordeaux, whose attraction is important for trade and culture. However, the emergency of new poles and new networks (La Rochelle 's university, Futuroscope, towns network « AIRE 198 »...) seems to be able to change this influence connection with Angoulême...
Villes moyennes et grandes villes intermédiaires dans les Pays de la Loire
Authors: Jeanneau Jacques
Published: March 2011

Loire River Countries are characterizing by a polycentred urban network. From where, every city (big- or small-sized) enjoys its selfcontained urban hinterland. However, the major three cities (Nantes metropolis and two intermediate big cities, Angers and Le Mans) are gaining by trumps bound with their location upon a chief region route. After a strong growth stage, nowadays the middle-sized five towns (Saint Nazaire, Laval, Cholet, La Roche-sur-Yon, Saumur) are at a standstill. They remain parochialist although they are threatened with fringing.
Quel avenir pour le couple La Rochelle-Rochefort ?
Authors: Marrou Louis
Published: March 2011

The distribution of urban settlements on the western edge of France, which is located in the central section of the so-called « Arc Atlantique », clearly indicates that the two urban centers Nantes and Bordeaux dominate the regional urban network. La Rochelle and Rochefort are situated on the Atlantic coast, halfway between these two urban areas. At the beginning of the 20th century, both cities were of similar size. Nevertheless, after nearly a century of urban growth, La Rochelle became predominant in its role as the « prefecture » (local capital city) of the department of « Charente-Maritime », and now has a population four times larger than its neighbour. This simple observation leads to a new interpretation of the spatial organisation pattern of this area which indicates that further cooperation between these two medium-sized towns (only 30 km apart) is now urgent. Indeed, such cooperation exists in the hinterland between Poitiers and Chatellerault on the Paris -Bordeaux axis. This paper thus seeks to explore an present the many possibilities of cooperation that may be developed between Rochefort and La Rochelle.
Les villes vendéennes, un réseau sous influences ?
Authors: Renard Roger
Published: March 2011

La Vendée, caracterizada desde hace tiempo por un estade exceptional de suburb anización, se ha dotado de 1954 a 1982 de un sembrado urbano relativamente denso organizado alrededor de La Roche-sur-Yon. La evolución comprabada desde 1982 ha marcado al contrario una interrupción muy évidente de este proceso : disminución de los movimientos migratorios hacia la region de La Roche-sur-Yon; debilitación del modelo de la región de Cholet (industrialización en el mundo rural); fortalecimiento de las atractividades exteriores al departamento (1) Nantes, Cholet y Bressuire particularmente.
Les villes en réseaux, nécessaires supports de l'Arc atlantique : coopération et développement entre Poitiers, Niort, Angoulême et La Rochelle
Authors: Royoux Dominique
Published: March 2011

eng : City networks, Intermunicipality at distance, Variable geometry territorises, Plan

spaces
Villes moyennes et réseaux de communication : l'exemple de Cholet
Authors: Wolff Jean-Pierre
Published: March 2011

Dans la communication proposée, il s'agit de souligner les relations qui peuvent exister entre des villes moyennes entre elles et des villes appartenant à d'autres rangs de taille. Nous prendrons quelques indicateurs comme les flux de circulation, les échanges et les zones d'attractivité. Pour des raisons d'exemplarité nous retiendrons le cas de Cholet dans le Grand Ouest regroupant Basse- Normandie, Bretagne et Pays de la Loire.
San Diego (Californie). Les enjeux de la gestion et de l'aménagement du littoral
Authors: Billard Gerald
Published: March 2011

San Diego, malgré le faible nombre d'études empiriques qui lui ont été consacré, s'avère s'imposer comme un terrain de recherche pertinent lorsqu'il s'agit d'aborder les problèmes de l'aménagement et de la gestion du littoral aux Etats-Unis.

L'espace littoral à San Diego, notamment dans une frange centrale et péri-centrale, subit une double pression du fait de l'affrontement entre développement privé et préservation du milieu.

Dans ce contexte de concurrence, l'étude des communautés résidentielles littorales permet d'appréhender une nouvelle forme de gestion des espaces côtiers qui repose sur l'intervention directe des résidents dans les politiques d' aménagement.
La crise de la pêche rochelaise à l'épreuve d'une stratégie portuaire mal calibrée
Authors: Chesnel Marc
Published: March 2011

Dans un contexte d' affaiblissement général de la pêche, lié à l'amoindrissement de la ressource, la construction du nouveau port de Chef-de-Baie ne semble pas être la solution pour réduire localement la crise : de quelle marge dispose la filière locale pour que la pêche tienne encore sa place à La Rochelle ?
Variation du niveau piézométrique des nappes phréatiques du bassin de l'Envigne (1982-1990)
Authors: Giret Alain
Published: March 2011

L'analyse fine du mouvement des eaux dans les puits du bassin de l'Envigne, comparée au régime des précipitations a permis de mettre en évidence la sensibilité locale des variations interannuelles et saisonnières d'une nappe aussi ample que celle des sables de Vierzon. Les pulsations pluviométriques à court terme des pluies efficaces de saison froide s'y ressentent parfaitement, alors que la drainance des nappes des niveaux supérieurs amortit l'impact des maigres estivaux. Il en résulte une nappe dont l'importance hydrologique n'a d'équivalent que son importance économique.
Endomorphisms of Two Dimensional Jacobians and Related Finite Algebras
Authors: Butske William
Published: March 2011

Zarhin proves that if C is the curve y2 = f (x) where Galℚ(f(x)) = Sn or An, then . In seeking to examine his result in the genus g = 2 case supposing other Galois groups, we calculate for a genus 2 curve where f (x) is irreducible. In particular, we show that unless the Galois group is S5 or A5, the Galois group does not determine .
On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity
Authors: Fuentes E. , Coe H. , Green D. , McFiggans G.
Published: March 2011

Abstract. The effect of nanogel colloidal and dissolved organic matter <0.2 μm, secreted by marine biota, on the hygroscopic growth and droplet activation behaviour of the primary marine aerosol was studied. Seawater proxies were prepared by the combination of artificial seawater devoid of marine organics and natural seawater enriched in organic exudate released by laboratory-grown phytoplankton cultures, as described in a companion paper. The primary aerosol was produced by bubble bursting, using a plunging multijet system as an aerosol generator. The aerosol generated from seawater proxies enriched with marine exudate presented organic volume fractions on the order of 8–37%, as derived by applying a simple mixing rule. The hygroscopic growth and cloud condensation nuclei (CCN) activity of the marine organics-enriched particles where 9–17% and 5–24% lower, respectively, than those of the aerosol produced from artificial seawater devoid of exudate. Experiments in a companion paper indicated that the cloud nuclei formation could be enhanced in diatom bloom areas because of the increase in the primary particle production induced by marine organics. The experiments in the present study, however, indicate that the impacts of such an enhancement would be counteracted by the reduction in the CCN activity of the primary particles enriched in marine organics. The extent of the effect of the biogenic matter on the particle behaviour was dependent on the seawater organic concentration and type of algal exudate. Aerosol produced from seawater proxies containing diatomaceous exudate presented higher hydrophobicity and lower CCN activity than those enriched with nanoplankton exudate. The organic fraction of the particles was found to correlate with the seawater organic concentration, without observing saturation of the particle organic mass fraction even for unrealistically high organic matter concentration in seawater. These findings are indicative that discrepancies on the composition of the primary aerosol between different studies could partly be explained by the difference in the nature and concentration of the organic matter in the source seawater employed. Consistently across the experiments, theoretical analysis based on the Köhler model predicted a reduction in the primary marine aerosol CCN activity upon the incorporation of marine organics into the particle composition. This effect is consequence of the replacement of small inorganic sea salt molecules by large molar mass organic molecules, together with a moderate suppression of the surface tension at the point of activation of 5–0.5%, which leads to a dominance of the reduction in the dissolved solute in the Raoult term.
Effect of humidity on the composition and yield of isoprene photooxidation secondary organic aerosol
Authors: Nguyen T. B. , Roach P. J. , Laskin J. , Laskin A. , Nizkorodov S. A.
Published: March 2011

Abstract. The effect of relative humidity (RH) on the composition and concentrations of gas-phase products and secondary organic aerosol (SOA) generated from the photooxidation of isoprene under high-NOx conditions was investigated. The yields of most gas-phase products were the same regardless of initial water vapor concentration with exception of hydroxyacetone and glycolaldehyde, which were considerably affected by RH. A significant change was observed in the SOA composition, with many unique condensed-phase products formed under humid (90% RH) vs. dry (<2% RH) conditions, without any observable effect on the rate and extent of the SOA mass growth. There is a 40% reduction in the number and relative abundance of distinct particle-phase organic nitrogen (ON) compounds detected by high resolution mass spectrometry. The suppression of condensation reactions, which produce water as a product, is the most important chemical effect of the increased RH. For example, the total signal from oligomeric esters of 2-methylglyceric acid was reduced by about 60% under humid conditions and the maximum oligomer chain lengths were reduced by 7–11 carbons. Oligomers formed by addition mechanisms, without direct involvement of water, also decreased at elevated RH but to a much smaller extent. The observed substantial reduction in the extent of condensation-type oligomerization at high RH may have substantial impact on the phase characteristics and hygroscopicity of the isoprene aerosol. The reduction in the amount of organic nitrates in the particle phase has implications for understanding the budget of ON compounds.
On transport phenomena and equilibration time scales in thermodenuders
Authors: Saleh R. , Shihadeh A. , Khlystov A.
Published: March 2011

Abstract. This paper presents a theoretical and experimental investigation of thermodenuders that addresses two controversial issues: (1) equilibration time scales and (2) the need for an activated carbon (AC) denuder in the cooling section. We describe a plug flow model for transport phenomena in a TD, which can be used to simulate the rate of vapor build-up in the gas phase and the corresponding change in particle size distribution. Model simulations were found to have excellent agreement with experiments performed with pure and mixed dicarboxylic acid aerosols. Both simulations and experiments showed that the aerosols approached equilibrium within reasonable residence times (15 s–30 s) for aerosol concentrations and size distributions typical for laboratory measurements, and that volatility studies at sufficiently high aerosol loadings, therefore, need not resort to kinetic models for inference of thermodynamic properties. However, for size distributions relevant for ambient aerosols, equilibration time scales were much larger than residence times available with current TD designs. We have also performed dimensional analysis on the problem of equilibration in TDs, and derived a dimensionless equilibration parameter which can be used to determine the residence time needed for an aerosol of given size distribution and kinetic properties to approach equilibrium. It is also shown theoretically and empirically that aerosol volatility has no effect on the equilibration time scales. Model simulations and experiments showed that with aerosol size distributions relevant to both ambient and laboratory measurements re-condensation in the cooling section, with and without an AC denuder, was negligible. Thus, there is no significant benefit in using an AC denuder in the cooling section. Due to the risk of stripping volatile material from the aerosol, the use of AC denuders in the cooling section should be avoided. Finally, we present a rationale for why ΔC is the proper measure of volatility, while using mass fraction remaining (MFR) can be misleading.
Retrieval of stratospheric aerosol density profiles from SCIAMACHY limb radiance measurements in the O2 A-band
Authors: Ovigneur B. , Landgraf J. , Aben I.
Published: March 2011

Abstract. In this paper we present an approach to retrieve stratospheric aerosol number densities in the altitude range 10–40 km from SCIAMACHY limb radiance measurements in the spectral range of the O2 A absorption band, near 760 nm. Here, the characteristic light paths differ for the measured light in the O2 A band and in the spectral continuum next to the absorption band. This difference is used to distinguish the effect of stratospheric aerosol scattering and ground reflection on the limb measurement. The capability to disentangle both effects is illustrated for SCIAMACHY limb observations over the Libyan desert, where the measurements are not affected by tropospheric clouds. Comparison of the SCIAMACHY retrieval and the SAGE II aerosol extinction product between 75 degrees Southern and Northern latitude shows the clear need for prior knowledge of the mean size of the stratospheric aerosol for the SCIAMACHY retrieval. We found best agreement between SCIAMACHY and SAGE II aerosol extinction for the period 2003–2005 for a prior choice of the mean aerosol size radius of 0.2 μm. The overall agreement between both data sets is in the range <50% root mean square difference at 14–30 km with a minimum of 30% at 22 km.
Influence of under-sampled a priori data on tropospheric NO2 satellite retrievals
Authors: Heckel A. , Kim S.-W. , Frost G. J. , Richter A. , Trainer M. , Burrows J. P.
Published: March 2011

Abstract. The retrieval of tropospheric columns of NO2 and other trace gases from satellite observations of backscattered solar radiation relies on the use of accurate a priori information. The spatial resolution of current space sensors is often significantly higher than that of the a priori datasets used, introducing uncertainties from spatial misrepresentation. In this study, the effect of spatial under-sampling of a priori data on the retrieval of NO2 columns was studied for a typical coastal area (around San Francisco). High-resolution (15 × 15 km2) NO2 a priori data from the WRF-Chem model in combination with high-resolution MODIS surface reflectance and aerosol data were used to investigate the uncertainty introduced by applying a priori data at typical global chemical transport model resolution. The results show that the relative uncertainties can be large (more than a factor of 2) for individual measurements, mainly due to spatial variations in NO2 profile and surface albedo, with smaller contributions from aerosols and surface height changes. Similar sensitivities are expected for other coastal regions and localised sources such as power plants, highlighting the need for high-resolution a priori data in quantitative analysis of the spatial patterns retrieved from satellite observations of tropospheric pollution.
Carbon monoxide apparent quantum yields and photoproduction in the Tyne estuary
Authors: Stubbins A. , Law C. S. , Uher G. , Upstill-Goddard R. C.
Published: March 2011

Abstract. Carbon monoxide (CO) apparent quantum yields (AQYs) are reported for a suite of riverine, estuarine and sea water samples, spanning a range of coloured dissolved organic matter (CDOM) sources, diagenetic histories, and concentrations (absorption coefficients). CO AQYs were highest for high CDOM riverine samples and almost an order of magnitude lower for low CDOM coastal seawater samples. CO AQYs were between 47 and 80% lower at the mouth of the estuary than at its head. Whereas, a conservative mixing model predicted only 8 to 14% decreases in CO AQYs between the head and mouth of the estuary, indicating that a highly photoreactive pool of terrestrial CDOM is lost during estuarine transit. The CDOM absorption coefficient (a) at 412 nm was identified as a good proxy for CO AQYs (linear regression r2 > 0.8; n = 12) at all CO AQY wavelengths studied (285, 295, 305, 325, 345, 365, and 423 nm) and across environments (high CDOM river, low CDOM river, estuary and coastal sea). These regressions are presented as empirical proxies suitable for the remote sensing of CO AQYs in natural waters, including open ocean water, and were used to estimate CO AQY spectra and CO photoproduction in the Tyne estuary based upon annually averaged estuarine CDOM absorption data. A minimum estimate of annual CO production was determined assuming that only light absorbed by CDOM leads to the formation of CO and a maximum limit was estimated assuming that all light entering the water column is absorbed by CO producing photoreactants (i.e. that particles are also photoreactive). In this way, annual CO photoproduction in the Tyne was estimated to be between 0.99 and 3.57 metric tons of carbon per year, or 0.004 to 0.014% of riverine dissolved organic carbon (DOC) inputs to the estuary. Extrapolation of CO photoproduction rates to estimate total DOC photomineralisation indicate that less than 1% of DOC inputs are removed via photochemical processes during transit through the Tyne estuary.
Effects of copper mineralogy and methanobactin on cell growth and sMMO activity in Methylosinus trichosporium OB3b
Authors: Chi Fru E. , Gray N. D. , McCann C. , Baptista J. de C. , Christgen B. , Talbot H. M. , El Ghazouani A. , Dennison C. , Graham D. W.
Published: March 2011

Abstract. Controls on in situ methanotroph activity are not well understood. One potentially important parameter is copper (Cu) because this metal is at the centre of particulate methane monooxygenase (pMMO), the most active enzyme involved in oxidizing methane to methanol. Furthermore, Cu-to-cell ratios influence the relative expression of pMMO versus the alternate soluble MMO (sMMO) in some species. Most methanotroph studies have only assessed readily soluble forms of Cu (e.g., CuCl2) atypical of real methanotroph habitats and there is a dearth of activity data associated with more common environmental Cu sources. Here we quantified sMMO activity and growth kinetics in Methylosinus trichosporium OB3b, an organism that expresses both pMMO and sMMO, when grown on Cu-minerals with differing dissolution equilibria to assess how mineral source and methanobactin (mb) influences growth. Mb is a molecule produced by M. trichosporium OB3b that has a high affinity for Cu, reduces Cu toxicity, mediates Cu uptake and may be key to Cu availability in terrestrial systems. Abiotic Cu-dissolution experiments showed that Cu release is affected by mb level, although mb only enhances Cu dissolution from sparingly soluble minerals, such as CuO and to a greater extent CuCO3·Cu(OH)2. However, the two minerals affected M. trichosporium OB3b growth very differently. Cells grew without growth lag and with active pMMO on CuCO3·Cu(OH)2, regardless of the amount of mineral supplied (< 500 μmoles Cu-total L−1). In contrast, they also grew well with CuO (< 50 μmoles Cu-total L−1), but instead had active sMMO, although sMMO activity was conditionally suppressed by supplemental mb and-or direct cell-mineral contact. Mb additions significantly increased growth rates (p<0.05) with both minerals. Results show mb broadly stimulates growth, but Cu mineralogy and mb dictate whether sMMO or pMMO is active in the cells. This has implications to in situ bioremediation and other studies on methanotroph function in terrestrial systems.
Influence of climate parameters on long-term variations of the distribution of phytoplankton biomass and nutrient concentration in the Baltic Sea simulated by a 3-D model
Authors: Dzierzbicka-Głowacka L. , Piskozub J. , Jakacki J. , Janecki M. , Nowicki A.
Published: March 2011

Abstract. Influence of long term trends in the climate parameters (average temperature, wind speed and solar irradiance) on phytoplankton and nutrient in the Baltic Sea was studied with an integrated three-dimensional coupled sea-ice ecological model. Simple ecosystem has been added to the sea-ice model and it has been used to estimate variability of the phytoplankton and nutrient during long term changes of the main atmospheric forces. Several numerical experiments were conducted to test the sensitivity of the model to changes of the main physical parameters such as temperature, wind speed, solar and thermal radiation (in different configurations). Influences of variability of these parameters on phytoplankton and nutrient (total inorganic nitrogen) is presented and discussion on relevance to expected future climate change is provided.