bluuebunny/crossref_metadata_2025 huggingface dataset:
Sources of variations in total column carbon dioxide
Authors: Keppel-Aleks G. , Wennberg P. O. , Schneider T.
Published: April 2011

Abstract. Observations of gradients in the total CO2 column, 〈CO2〉, are expected to provide improved constraints on surface fluxes of CO2. Here we use a general circulation model with a variety of prescribed carbon fluxes to investigate how variations in 〈CO2〉 arise. On diurnal scales, variations are small and are forced by both local fluxes and advection. On seasonal scales, gradients are set by the north-south flux distribution. On synoptic scales, variations arise due to large-scale eddy-driven disturbances of the meridional gradient. In this case, because variations in 〈CO2〉 are tied to synoptic activity, significant correlations exist between 〈CO2〉 and dynamical tracers. We illustrate how such correlations can be used to describe the north-south gradients of 〈CO2〉 and the underlying fluxes on continental scales. These simulations suggest a novel analysis framework for using column observations in carbon cycle science.
Vertical profiles of nitrous acid in the nocturnal urban atmosphere of Houston, TX
Authors: Wong K. W. , Oh H.-J. , Lefer B. L. , Rappenglück B. , Stutz J.
Published: April 2011

Abstract. Nitrous acid (HONO) often plays an important role in tropospheric photochemistry as a major precursor of the hydroxyl radical (OH) in early morning hours and potentially during the day. However, the processes leading to formation of HONO and its vertical distribution at night, which can have a considerable impact on daytime ozone formation, are currently poorly characterized by observations and models. Long-path differential optical absorption spectroscopy (LP-DOAS) measurements of HONO during the 2006 TexAQS II Radical and Aerosol Measurement Project (TRAMP), near downtown Houston, TX, show nocturnal vertical profiles of HONO, with mixing ratios of up to 2.2 ppb near the surface and below 100 ppt aloft. Three nighttime periods of HONO, NO2 and O3 observations during TRAMP were used to perform model simulations of vertical mixing ratio profiles. By adjusting vertical mixing and NOx emissions the modeled NO2 and O3 mixing ratios showed very good agreement with the observations. Using a simple conversion of NO2 to HONO on the ground, direct HONO emissions, as well as HONO loss at the ground and on aerosol, the observed HONO profiles were reproduced by the model for 1–2 and 7–8 September in the nocturnal boundary layer (NBL). The unobserved increase of HONO to NO2 ratio (HONO/NO2) with altitude that was simulated by the initial model runs was found to be due to HONO uptake being too small on aerosol and too large on the ground. Refined model runs, with adjusted HONO uptake coefficients, showed much better agreement of HONO and HONO/NO2 for two typical nights, except during morning rush hour, when other HONO formation pathways are most likely active. One of the nights analyzed showed an increase of HONO mixing ratios together with decreasing NO2 mixing ratios that the model was unable to reproduce, most likely due to the impact of weak precipitation during this night. HONO formation and removal rates averaged over the lowest 300 m of the atmosphere showed that NO2 to HONO conversion on the ground was the dominant source of HONO, followed by traffic emission. Aerosol did not play an important role in HONO formation. Although ground deposition was also a major removal pathway of HONO, net HONO production at the ground was the main source of HONO in our model studies. Sensitivity studies showed that in the stable NBL, net HONO production at the ground tends to increase with faster vertical mixing and stronger NOx emission. Vertical transport was found to be the dominant source of HONO aloft.
Seasonal differences in the vertical profiles of aerosol optical properties over rural Oklahoma
Authors: Andrews E. , Sheridan P. J. , Ogren J. A.
Published: April 2011

Abstract. A small airplane made more than 450 aerosol optical property (light absorption and light scattering) vertical profile measurements (up to 4 km) over a rural Oklahoma site between March 2000 and July 2005. These profiles suggest significant seasonal differences in aerosol properties. The highest amounts of scattering and absorbing aerosol are observed during the summer, while the relative contribution of aerosol absorption is highest in the winter (i.e., single scattering albedo is lowest in winter). Aerosol absorption generally decreased with altitude below ∼1.5 km and then was relatively constant above that. Aerosol scattering decreased sharply with altitude below ∼1.5 km but, unlike absorption, also decreased at higher altitudes, albeit less sharply. The seasonal variability observed for aerosol loading is consistent with other aerosol measurements in the region including AERONET aerosol optical depth (AOD), CALIPSO vertical profiles, and IMPROVE aerosol mass. The column averaged single scattering albedo derived from in situ airplane measurements shows a similar seasonal cycle as the AERONET single scattering albedo inversion product, but a comparison of aerosol asymmetry parameter from airplane and AERONET platforms suggests differences in seasonal variability. The observed seasonal cycle of aerosol loading corresponds with changes in air mass back trajectories: the aerosol scattering was higher when transport was from polluted areas (e.g., the Gulf Coast) and lower when the air came from cleaner regions and/or the upper atmosphere.
Chemical and physical transformations of organic aerosol from the photo-oxidation of open biomass burning emissions in an environmental chamber
Authors: Hennigan C. J. , Miracolo M. A. , Engelhart G. J. , May A. A. , Presto A. A. , Lee T. , Sullivan A. P. , McMeeking G. R. , Coe H. , Wold C. E. , Hao W.-M. , Gilman J. B. , Kuster W. C. , de Gouw J. , Schichtel B. A. , Collett J. L. , Kreidenweis S. M. , Robinson A. L.
Published: April 2011

Abstract. Smog chamber experiments were conducted to investigate chemical and physical transformations of organic aerosol (OA) during photo-oxidation of open biomass burning emissions. The experiments were carried out at the US Forest Service's Fire Science Laboratory as part of the third Fire Lab at Missoula Experiment (FLAME III). We investigated 12 different fuels commonly burned in North American wildfires. The experiments feature atmospheric and plume aerosol and oxidant concentrations; aging times ranged from 3–4.5 h. OA production, expressed as a mass enhancement ratio (ratio of OA to primary OA (POA) mass), was highly variable. OA mass enhancement ratios ranged from 2.9 in experiments where secondary OA (SOA) production nearly tripled the POA concentration, to 0.7 in experiments where photo-oxidation resulted in a 30% loss of the OA mass. The campaign-average OA mass enhancement ratio was 1.7 ± 0.7 (mean ± 1 σ); therefore, on average, there was substantial SOA production. In every experiment, the OA was chemically transformed. Even in experiments with net loss of OA mass, the OA became increasingly oxygenated and less volatile with aging, indicating that photo-oxidation transformed the POA emissions. Levoglucosan concentrations were also substantially reduced with photo-oxidation. The transformations of POA were extensive; using levoglucosan as a tracer for POA, unreacted POA only contributed 17% of the campaign-average OA mass after 3.5 h of exposure to typical atmospheric hydroxyl radical (OH) levels. Heterogeneous reactions with OH could account for less than half of this transformation, implying that the coupled gas-particle partitioning and reaction of semi-volatile vapors is an important and potentially dominant mechanism for POA processing. Overall, the results illustrate that biomass burning emissions are subject to extensive chemical processing in the atmosphere, and the timescale for these transformations is rapid.
Analysis of vegetation and land cover dynamics in north-western Morocco during the last decade using MODIS NDVI time series data
Authors: Höpfner C. , Scherer D.
Published: April 2011

Abstract. Vegetation phenology as well as current variability and dynamics of vegetation and land cover including its climatic and human drivers are examined in a region in north-western Morocco of nearly 22 700 km2. A gapless time series of Normalized Differenced Vegetation Index (NDVI) composite raster data from 29 September 2000 to 29 September 2009 with a spatial resolution of 250 m and acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor is utilised. The presented approach allows to compose and analyse yearly land cover maps in a widely unknown region with scarce validated ground truth data by deriving phenological parameters. Results show that high temporal resolution of 16 d is sufficient (a) for determining land cover better than global land cover classifications of Plant Functional Types (PFT) and Global Land Cover 2000 (GLC2000), and (b) for drawing conclusions on vegetation dynamics and its drivers. Areas of stably classified land cover types show climatically driven inter- and intra-annual variability with indicated influence of droughts. The presented approach to determine human-driven influence on vegetation dynamics caused by agriculture results in a more than ten times larger area compared to the stably classified areas. Change detection based on yearly land cover maps shows a gain of high-productive vegetation (cropland) of about 259.3 km2. However, statistically significant inter-annual trends in vegetation dynamics during the last decade could not be discovered. A sequence of correlations was done to extract the most important period of rainfall for production of green biomass and for the extent of land cover types, respectively. Results show that mean daily precipitation from 1 October to 15 December has high correlation results (max. r2=0.85) at intra-annual time scale to NDVI percentiles (50%) of land cover types. Correlation results of mean daily precipitation from 16 September to 15 January and percentage of yearly classified area of each land cover type are medium up to high (max. r2=0.64). In all, an offset of nearly 1.5 months is detected between precipitation rates and NDVI in 16 d steps. High-productive vegetation (cropland) is proved to be mainly rain-fed. We conclude that identification, understanding and knowledge about vegetation phenology, and current variability of vegetation and land cover as well as prediction methods of land cover change can be improved using multi-year MODIS NDVI time series data. This study enhances the comprehension of current land surface dynamics and variability of vegetation and land cover in north-western Morocco offering a fast access especially for estimating the extent of agricultural lands.
Modelling irrigated maize with a combination of coupled-model simulation and ensemble forecasting, in the west of China
Authors: Li Y. , Kinzelbach W. , Zhou J. , Cheng G. D. , Li X.
Published: April 2011

Abstract. The hydrologic model HYDRUS-1D and the crop growth model WOFOST were coupled to efficiently manage water resources in agriculture and improve the prediction of crop production through the accurate estimation of actual transpiration with the root water uptake method and a soil moisture profile computed with the Richards equation during crop growth. The results of the coupled model are validated by experimental studies of irrigated-maize done in the middle reaches of northwest China's Heihe River, a semi-arid to arid region. Good agreement was achieved between the simulated evapotranspiration, soil moisture and crop production and their respective field measurements made under maize crop. However, for regions without detailed observation, the results of the numerical simulation could be unreliable for policy and decision making owing to the uncertainty of model boundary conditions and parameters. So, we developed the method of combining model simulation and ensemble forecasting to analyse and predict the probability of crop production. In our studies, the uncertainty analysis was used to reveal the risk of facing a loss of crop production as irrigation decreases. The global sensitivity analysis was used to test the coupled model and further quantitatively analyse the impact of the uncertainty of coupled model parameters and environmental scenarios on crop production. This method could be used for estimation in regions with no or reduced data availability.
Surgical Management of Congenital Pupillary-Iris-Lens Membrane
Authors: Yu Tao , Yin Zheng Qin , Yang Hong
Published: April 2011

Purpose

To describe the surgical interventions in congenital pupillary-iris-lens membrane. Six patients with congenital pupillary-iris-lens membrane presented with partial or totally occluded pupils, or increased intraocular pressure (IOP).

Methods

We describe the value of creating 2 paracenteses. The first one is made in the lower temporal quadrant and accommodates a 20-gauge anterior chamber maintainer (ACM). The second paracentesis is made in an upper quadrant and serves to cut the membrane with a vitrectomy probe.

Results

The technique was performed in 6 eyes of 6 children aged 4 to 10 months from March 2007 to July 2008 at Southwest Eye Hospital. These patients had congenital pupillary-iris-lens membrane with partial or totally occluded pupils, or increased IOP due to iris bombe or angle closure. No secondary glaucoma has been detected in the follow-up period. The visual acuity before the operations was less than 0.05 with preferential looking (PL), while the visual acuity was improved to 0.5 in 4 out of 6 eyes and 0.3 in 2 eyes in the last follow-up.

Conclusions

The ACM and vitrectomy probe are important tools in the surgical management of congenital pupillary-iris-lens membrane because they facilitate the surgical procedure and reduce iatrogenic damage to the lens. Timely surgical intervention can abort the progressive pupillary occlusion or angle closure glaucoma.
Extracorporeal Membrane Oxygenation in 108 Patients with Low Cardiac Output – a Single-Center Experience
Authors: Beiras-Fernandez Andres , Deutsch Marcus-André , Kainzinger Sandra , Kaczmarek Ingo , Sodian Ralf , Ueberfuhr Peter , Meiser Bruno , Schmoeckel Michael , Reichart Bruno , Brenner Paolo
Published: April 2011

Background

For short-term ventricular and pulmonary support the extracorporeal membrane oxygenation (ECMO) system using the Bio-Medicus centrifugal pump (Medtronic®, Minneapolis, MN, USA) was applied in 108 patients with cardiac low-output.

Methods

From December 1996 to July 2006 the ECMO was implanted in 108 patients (73 adult, mean age: 49.3±18.0 yrs and 35 children, mean age: 1.3 ± 2.7 yrs) with mostly postcardiotomy cardiac low output. The surgical procedures included congenital heart surgery (n=35), heart transplantation (HTx) (n=21), coronary artery bypass operation (CABG) and/or valvular operation (n=33), other operations (n=6) and 13 patients with ECMO support for bridge to recovery.

Results

The mean supporting time was 5.1±5.6 days. Overall, 30-day-survival was 40.2%. Best survival rates were seen after congenital heart surgery (24/35, 65.7%) and after HTx (9/21, 42.9%); the worst rates were in the group of CABG and/or valvular operations (5/33, 15.2%), only ECMO support (3/13, 23.1%) and other operations (1/6, 16.7%). Fifty-four patients died while supported by ECMO, 15 were weaned from ECMO but died in hospital, 39 patients were weaned and survived. Causes of death were multi-organ failure (40.6%), bleeding (23.2%), persistent cardiac low output (21.7%), thrombembolic events (8.7%), and graft failure (5.8%). Markers for adverse outcome were identified as older age, high body weight, increased AST/GOT levels, and lower thrombocyte count in adults; and as higher levels of serum creatinine in pediatric patients.

Conclusions

ECMO support showed best results in pediatric patients after congenital heart surgery and in patients after HTx in contrast to multimorbid, older patients with often irreversible myocardial damage.
External Validation and Comparison of Three Scores to Predict Renal Replacement Therapy after Cardiac Surgery: A Multicenter Cohort
Authors: Vives Marc , Monedero Pablo , Perez-Valdivieso José Ramón , Garcia-Fernandez Nuria , Lavilla Javier , Herreros Jesús , Bes-Rastrollo Maira
Published: April 2011

Purpose

Cardiac surgery-associated acute kidney injury requiring renal replacement therapy (RRT) is independently associated with mortality. Several risk scores have been developed to predict the need for RRT after cardiac surgery. We have compared and verified the external validity of the three main available scores for RRT prediction after cardiac surgery: the Thakar score, the Mehta tool, and the Simplified Renal Index.

Methods

The risk scores were calculated in a cohort of 1084 adult patients, 248 of whom required RRT, who underwent open-heart surgery in 24 Spanish hospitals in 2007. The performance of the systems was determined by examining their discrimination (areas under the receiver operating characteristic curves (aROC) and calibration (Lemeshow-Hosmer chi-square goodness-of-fit statistics). Results: The aROCs in the Thakar score, the Mehta tool, and the Simplified Renal Index were 0.82, 0.76 and 0.79, respectively. The three scoring systems were poorly calibrated and tended to underestimate the actual need for RRT.

Conclusions

The Thakar score and the Simplified Renal Index discriminated well between low - and high-risk patients in our cohort, and Thakar outperformed the Mehta tool. These best-performing scores may aid in the selection of optimal therapy, facilitate the planning of hospital resource utilization, improve preoperative counseling, select participants for clinical trials of renal-protective therapies and enable an accurate comparison between different institutions or surgeons.
Factors Influencing Knowledge Sharing among Undergraduate Students
Authors: Ong Hway-Boon , Yeap Peik-Foong , Tan Siow-Hooi , Chong Lee-Lee
Published: April 2011

Knowledge sharing can enhance learning and help to build the knowledge workforce. This paper reports on a study of knowledge sharing behaviour among undergraduate students in Malaysia. Knowledge sharing was found to be influenced by the mechanisms used, various barriers to communication and the motivations behind knowledge sharing. The mechanisms include online communication, social interaction, off-campus activities and learning activities. It was found that problems with information and communications technology (ICT), lack of self confidence, external constraints, self-centredness and social attributes can create barriers to knowledge exchange. It is concluded that the motivation to share knowledge appears to be affected by relationships, rewards and the level of satisfaction with knowledge sharing activities.
Agricultural Productivity Growth in the Euro-Med Region: Is There Evidence of Convergence?
Authors: Galanopoulos Konstantinos , Surry Yves , Mattas Konstadinos
Published: April 2011

This paper measures agricultural productivity growth by means of the sequential Malmquist Total Factor Productivity (TFP) index among a set of 32 West European, Central and East European (CEE), and Middle Eastern and North African (MENA) countries for the period 1961–2002. In a second stage, the authors also investigate whether this measure is converging among these countries by employing cross-sectional tests for absolute and conditional β-convergence as well as for club convergence. The results suggest that, despite the fact that the CEE and MENA countries have exhibited a high rate of productivity growth since the 1990s, absolute convergence cannot be confirmed. Evidence for conditional convergence is still found and the formation of two separate clubs of countries that converge to different equilibrium points is identified.
A Retrospective View of the EU's Cotton Production, and Future Perspectives
Authors: Mattas Konstadinos , Tsakiridou Efthimia , Botonaki Anna , Tsiboukas Konstadinos
Published: April 2011

The expansion of the European Union (EU) to include Greece and Spain in 1981 and 1986 respectively led to an expansion of sectors protected under the Common Agricultural Policy (CAP), which included cotton. In the subsequent decades, the EU's cotton policy has undergone several revamping attempts. By bringing cotton production and processing under the EU umbrella, EU policy makers admitted the role and significance of its production for the agriculture and economy of southern Europe. Nevertheless, the course of this policy has been highly contentious, and will probably remain so for years to come. This paper offers a retrospective view of the EU's cotton policy and then considers current and future perspectives of the cotton sector, as cotton, a commodity that is produced worldwide and a basic input for the textile and clothing industry, attracts the interest of both EU and world agriculture.
The ‘Livestock Revolution’: Rhetoric and Reality
Authors: Pica-Ciamarra Ugo , Otte Joachim
Published: April 2011

The unprecedented growth in developing countries in the demand for food of animal origin, dubbed the ‘Livestock Revolution’, is expected to give rise to major opportunities and threats worldwide. This assumption tends to dominate the policy debate, and inadequate attention is given to regional and national specificities. This paper presents an exploratory cross-country analysis of trends in the consumption of animal-source food in 88 developing countries during 1980–2003. It provides evidence that the Livestock Revolution has been, at least so far, a very circumscribed phenomenon affecting only few countries. However, a large share of the world's population lives in countries that are recording remarkable increases in the consumption of animal-source food. The question remains whether the term ‘Livestock Revolution’ is appropriate to represent trends that have hitherto involved only a minority of developing countries
International Trade and Exotic Pests: The Risks for Biodiversity and African Economies
Authors: Youm Ousmane , Vayssières Jean-François , Togola Abou , Robertson Shawn P. , Nwilene Francis E.
Published: April 2011

Trade is important for economic development and growth; however, it is also the principal means of introducing invasive pests and disease vectors that can cause environmental damage and economic losses and pose a serious risk to biodiversity. Invasive pests and trade have created a two-way linkage, leading to perceptions that African countries are becoming a source of invasive pests in other countries via trade. What phytosanitary measures do African countries have to take therefore to reduce losses in economic and trade opportunities? Another important issue is the ability of African countries to reduce trade-related pest invasions from other countries and the impact of such invasions on African economies and the environment. Management strategies that can reduce the introduction of exotic pests, while not restricting the benefits of trade or causing protective trade barriers, are desirable. This paper reviews linkages between trade and invasive pests and the resulting effects on African agricultural exports, the economy, environment and biodiversity. Strategies and policies to deal with invasive pests, trade and trade barriers and protectionism are reviewed to assess how they may affect or can be used by African countries to address these problems.
The Future Outlook for Portuguese Travel Agents
Authors: Assaf A. George , Barros Carlos Pestana , Machado Luiz Pinto
Published: April 2011

This paper adopts a three-stage procedure to measure and test the productivity and efficiency standings of Portuguese travel agents during 2005–2007. In the first stage, the authors use a bootstrapped Malmquist index approach to obtain estimates of total productivity growth. In the second stage, they obtain year-by-year efficiency scores, using a bootstrapped DEA model. A bootstrapped truncated regression is then adopted in the third stage to identify the covariates that explain technical efficiency. Results from a sample of 25 agents indicate that, on average, Portuguese agents experienced an increase in productivity over the period of the study. On the efficiency side, however, most travel agents were found to be operating at a high degree of inefficiency. Differences in productivity and efficiency between individual travel agents appeared to be related to factors such as market share and management style. The results are discussed and policy implications are derived.
A Study of the Agglomeration of China's Convention Industry: An Economic and Neo-Economic Geography Framework Approach
Authors: Zhang Yan , Qu Hailin , Guo Yingzhi
Published: April 2011

Accompanying the expansion of its opening up to the outside world, China has witnessed a steady increase in the area of international and regional communication, which has led to rapid development in the convention industry. This paper investigates the factors influencing the agglomeration of China's major convention-hosting cities under the framework of economic and neo-economic geography. The results of an empirical analysis reveal that factors such as a city's political or economic importance, service industry, regional GDP per capita and information accessibility are important aspects that may have an impact on the agglomeration of China's convention industry.
Does an Optimal Firm Size Exist for Publicly Traded US Hotels?
Authors: Park Kwangsoo , Lee Seoki
Published: April 2011

This study examines whether or not there is an optimal firm size for publicly traded US hotels. More specifically, the study tests a three-stage relationship based on economies and diseconomies of scale: the first stage, in which firm value increases as firm size increases; the second stage, in which firm value remains constant as firm size increases beyond the first stage; and the third stage, in which firm value decreases as firm size transcends the second stage. The study uses the Newey–West heteroskedasticity and the autocorrelation consistent (HAC) standard errors estimation in pooled regression analysis. Findings partially support the proposed relationship.
Angiomyolipoma of the Right Adrenal Gland
Authors: Yener Oktay , Özçelik Alp
Published: April 2011

Adrenal angiomyolipoma is rare. Only four cases have been reported so far. These are commonly found in Kidney but extrarenal sites are also mentioned. Angiomyolipoma arising in adrenal is very rare entity, usually asymptomatic, diagnosed incidentally on radiological investigation of abdomen for other conditions. We report our experience with a 45-year-old woman who presented with epigastric discomfort. A computerised tomography (CT) scan showed an adrenal mass. Laparoscopic adrenalectomy was performed and the histopathological features confirmed the diagnosis of adrenal angiomyolipoma. The patient recovered without any complications following surgery.
Estimation of Long-Term Stiffness of Storage Aged GFRP Composite Samples Immersed in HCl Acid by TTSP Method
Authors: Bagherpour Salar , Bagheri Rouholah , Saatchi Ahmad
Published: April 2011

The 15-year storage aged GFRP composite dumbbell-shaped specimens were immersed in concentrated HCl at different temperatures and times. The Young modulus, which is a yardstick of stiffness of the samples, was measured. The long-term stiffness at any time and temperature was predicted by using the master curve of stiffness obtained based on our accelerated testing results. In the first, second, third, and fourth years of the prediction the stiffness was  6800, 6400, 5550, and 5150 MPa, respectively. SEM micrographs of typical samples showed failure mode at the interface. The strength showed reduction due to degradation of fiber/matrix interfacial bond. The best match of our prediction obtained by using error function was between the first and the third years.
Multiple Endocrine Neoplasia 2a Presenting with Pheochromocytoma and Pituitary Macroadenoma
Authors: Heinlen Jonathan E. , Buethe David D. , Culkin Daniel J. , Slobodov Gennady
Published: April 2011

Multiple Endocrine Neoplasia type 2A (MEN-2a) is a rare disease associated with tumors of endocrine organs. Presentation most commonly is with medullary thyroid cancer and infrequently with other complaints. Pituitary adenoma has been seen coincidentally with this disease very rarely. Presented is a case of coincident MEN-2a with a symptomatic pituitary adenoma and an asymptomatic pheochromocytoma. A brief review is also provided.
Simultaneous Territories: Unveiling the Geographies of Latin American Cities
Authors: del Real Patricio
Published: April 2011

The harmonious, utopian image that housing in Latin America exuded across the world in the postwar years is very much at odds with the current view of the region, in which unbridled shantytowns dominate. Patricio del Real sets out to understand how such a rupture might have been possible: What was the process of exclusion at play in these Modernist projects? How does Modernism represent simultaneous territories in which emerging challenges to the social and political status quo were merely muffled by the architectural seduction of the 1950s?. Copyright © 2011 John Wiley & Sons, Ltd.
The Experimental Housing Project (PREVI), Lima: The Making of a Neighbourhood
Authors: García‐Huidobro Fernando , Torres Torriti Diego , Tugas Nicolás
Published: April 2011

The original vision at PREVI‐Lima was only ever partially realised: less than a third of the 1,500 planned housing units were built and the governmental crisis of the late 1960s meant that the occupants were left to their own devices. Fernando García‐Huidobro, Diego Torres Torriti and Nicolás Tugas look at how, abandoned by the authorities, the families at PREVI turned into incidental architects, completing the project and rendering the neighbourhood an integrated part of the city. Copyright © 2011 John Wiley & Sons, Ltd.
Tlacolula Social Housing, Oaxaca, Mexico
Authors: Arquitectos Dellekamp
Published: April 2011

Oaxaca in southern Mexico is one of the most economically marginal states in the country, with a large portion of its population requiring social housing. This has been further exacerbated by the widespread adoption of a suburban American housing model that has led to local communities becoming socially and culturally alienated. At Tlacolula, in Oaxaca, Dellekamp Arquitectos describe how they have set out to create a housing development that engenders locality and a sense of community through a traditional barrio neighbourhood design. Copyright © 2011 John Wiley & Sons, Ltd.
A City Talks: Learning from Bogotá’s Revitalisation
Authors: Peñalosa Enrique
Published: April 2011

As the Mayor of Bogotá (1998‐2001), Enrique Peñalosa transformed Colombia's capital from a city without hope to one that is held up as an international example of best practice. This was epitomised by his far‐reaching transport policy and the TransMilenio bus‐based transit system. Peñalosa describes the ambitious urban revitalisation programme that his administration undertook and how they were guided by the fundamental aim of ‘the construction of equality’. Copyright © 2011 John Wiley & Sons, Ltd.
From Product to Process: Building on Urban‐Think Tank’s Approach to the Informal City
Authors:   Interview with, Brillembourg Alfredo , Navarro‐Sertich Adriana
Published: April 2011

Adriana Navarro‐Sertich interviews a pioneer of the informal in architecture, co‐founder and co‐director of Urban‐Think Tank (U‐TT) Alfredo Brillembourg. Brillembourg explains how U‐TT's work seeks to connect informal settlements with the formal city, enabling inhabitants to access services and infrastructure. U‐TT is now taking the lessons it has learnt in working in Latin American cities, such as Caracas and São Paulo, elsewhere in the world with the aim of ‘working globally and acting locally’. Copyright © 2011 John Wiley & Sons, Ltd.
Interface, Flows and Transfer in an Electromagnetic Process Devoted to Liquid/Liquid Extraction
Authors: Courtessole Cyril , Etay Jacqueline
Published: April 2011

In ladle metallurgical processing, two liquid layers, a metallic phase below a salty or oxide phase, are separated by an interface where mass exchanges occur via redox reactions. The associated mass transfer is strongly dependent on the agitation of each phase, as well as of the interface. By means of induction, a cold‐crucible reactor can melt, confine and stir liquids at very‐high temperature without physical contact, with opportunities for continuous treatment. Equipment is built to control and measure the full kinetic transfer of a pollutant from one phase to another. This equipment, the associated orders of magnitude, and numerical simulations when it operates are presented.
Drug Delivery: Bio‐inspired Heterostructured Bead‐on‐String Fibers That Respond to Environmental Wetting (Adv. Funct. Mater. 8/2011)
Authors: Tian Xuelin , Bai Hao , Zheng Yongmei , Jiang Lei
Published: April 2011

Inspired by the geometric structure of ecribellate spider capture silk and its spinning characteristics, we propose a one‐step electrohydrodynamic method to fabricate bead‐on‐string heterostructured fibers (BSHFs). By combining electrospinning and electrospraying strategies using a sprayable outer fluid with low viscosity and a spinnable inner fluid with high viscosity in a coaxial jetting process, hydrophilic poly(ethylene glycol) beads are successfully imprinted on a hydrophobic polystyrene string. It is demonstrated that the BSHFs are capable of intelligently responding to environmental change. With a change in relative humidity, the fibers show a segmented swelling and shrinking behavior in the “bead” parts whereas the “string” parts remain the same. The elastic BSHFs with alternating hydrophilic and hydrophobic surface characteristics represent a type of mesoscale analogues that block copolymers and may bring about new properties and applications. Moreover, the combined electrohydrodynamic approach developed herein should open new routes to multifunctional one‐dimensional heterostructured materials.
Lenalidomide, cyclophosphamide and dexamethasone (CRd) for newly diagnosed multiple myeloma: Results from a phase 2 trial
Authors: Kumar Shaji K. , Lacy Martha Q. , Hayman Suzanne R. , Stewart Keith , Buadi Francis K. , Allred Jacob , Laumann Kristina , Greipp Philip R. , Lust John A. , Gertz Morie A. , Zeldenrust Steven R. , Bergsagel P. Leif , Reeder Craig B. , Witzig Thomas E. , Fonseca Rafael , Russell Stephen J. , Mikhael Joseph R. , Dingli David , Rajkumar S. Vincent , Dispenzieri Angela
Published: April 2011

The combination of lenalidomide and low‐dose dexamethasone is an effective treatment for multiple myeloma (MM). Addition of alkylating agents to lenalidomide or thalidomide results in increased response rates and deeper responses. We designed this trial to study the combination of cyclophosphamide, lenalidomide, and dexamethasone (CRd) as initial therapy for MM. Fifty‐three patients with previously untreated symptomatic MM was enrolled. Patients received 4‐week treatment cycles consisting of lenalidomide (25 mg daily for 3 weeks), dexamethasone (40 mg weekly), and cyclophosphamide (300 mg/m2 weekly for 3 weeks). A partial response or better was seen in 85% of patients including 47% with a very good partial response or better. The toxicities were manageable with over 80% of planned doses delivered; six patients went off study for toxicity. The median progression free survival (PFS) for the entire group was 28 months (95% CI: 22.7–32.6) and the overall survival (OS) at 2 years was 87% (95% CI: 78–96). Importantly, 14 patients with high‐risk MM had similar PFS and OS as the standard‐risk patients (n = 39). CRd is an effective and well‐tolerated regimen for upfront therapy of MM with high response rates and excellent 2‐year OS, and is suitable for long‐term therapy. Am. J. Hematol. 2011. © 2011 Wiley‐Liss, Inc.
Atopic profile of patients failing medical therapy for chronic rhinosinusitis
Authors: Tan Bruce K. , Zirkle Whitney , Chandra Rakesh K. , Lin David , Conley David B. , Peters Anju T. , Grammer Leslie C. , Schleimer Robert P. , Kern Robert C.
Published: April 2011

Background

Chronic rhinosinusitis (CRS) is an inflammatory condition of the nasal airway and paranasal sinuses that can broadly be classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). The relationship between CRS and atopy to inhalant allergens remains unclear. We sought to examine the presence of atopy in patients failing medical therapy for both types of CRS. The objective of this research was to analyze the frequency and distribution of allergen sensitivity in patients failing medical therapy for CRSwNP and CRSsNP in comparison to rhinitis patients without CRS and the general population.

Methods

A prospectively collected database of 334 consecutive CRS patients who had surgery after failing maximal medical therapy was queried to identify those who met inclusion criteria: a sinus computed tomography (CT), an endoscopy consistent with CRS, and skin‐prick testing with 24 common inhalant allergens in 8 classes at our institution (n = 125). Additionally, data from these CRS patients were compared to a group of 50 patients diagnosed with rhinitis who had similar symptoms but radiologically normal CT scans, as well as published normative population skin‐prick testing data obtained from the National Health and Nutrition Examination Study III (NHANES III). The relationship between atopy, as assessed by the frequency of skin test positivity, and radiological disease severity, was assessed for several allergen classes in CRSwNP, CRSsNP and rhinitis patients.

Results

One or more positive skin results were observed in 103 of 125 (82.4%) CRS patients who underwent surgery—a prevalence significantly higher than that found in the NHANES III study (p < 0.05) but not different from the rhinitis control group (36/50, 72.0%). The most prevalent positive skin test results were to dust mites and ragweed in CRSwNP, CRSsNP, and rhinitis patients. Comparing these 3 patient groups, there were no significant differences in the rates of positive skin‐test results to any single allergen. However, the median number of skin test–positive results was higher in CRSwNP patients compared to CRSsNP and rhinitis patients. Consistent with other studies, we found that CRSwNP patients were more likely to be male and have concurrent asthma.

Conclusion

In our series of patients failing medical therapy for CRS, we found higher rates of atopy compared with the general population but not compared with rhinitis patients. CRSwNP patients with medically refractory sinusitis were more likely to have multiple positive skin tests and asthma as compared to the general population or patients with either CRSsNP or rhinitis. Host barrier dysfunction may play a role in enabling multisensitization. © 2011 ARS‐AAOA, LLC.
Acid and base secretion in freshly excised nasal tissue from cystic fibrosis patients with ΔF508 mutation
Authors: Cho Do‐Yeon , Hwang Peter H. , Illek Beate , Fischer Horst
Published: April 2011

Background

Cystic fibrosis (CF) is caused by a misfunctional CF transmembrane conductance regulator (CFTR) protein, which is believed to contributes to the regulation of the airway surface liquid (ASL) pH. This study investigated acid and base secretion in freshly excised human nasal tissues from CF patients homozygous for the ΔF508 mutation.

Methods

Human nasal mucosa was collected during sinus surgery and investigated in Ussing chambers. Mucosal equilibrium pH values and rate of acid and base secretion were determined using the pH‐stat technique.

Results

The equilibrium pH of nasal epithelia from ΔF508 CF patients with chronic rhinosinusitis (CRS) was pH = 7.08 ± 0.09 and was significantly lower compared to nasal epithelia from CRS patients without CF (pH = 7.33 ± 0.06) and normal subjects (pH = 7.34 ± 0.08, n = 6). The rate of base secretion in CF nasal tissues was 11.8 ± 2.4 nmol · min−1 · cm−2, which was significantly lower than normal (57.2 ± 9.2 nmol · min−1 · cm−2). The HCO3− secretory rate was further increased by forskolin by 16.1% in normal, but not in CF tissues.

Conclusion

Our data suggests that CF patients exhibited significantly lower base secretion by the nasal airway epithelium. It is possible that improper regulation of ASL pH in CF may negatively impact the innate host defense system. © 2011 ARS‐AAOA, LLC.
Inflammation after trauma: Microglial activation and traumatic brain injury
Authors: Ramlackhansingh Anil F. , Brooks David J. , Greenwood Richard J. , Bose Subrata K. , Turkheimer Federico E. , Kinnunen Kirsi M. , Gentleman Steve , Heckemann Rolf A. , Gunanayagam Karen , Gelosa Giorgio , Sharp David J.
Published: April 2011

Objective:

Patient outcome after traumatic brain injury (TBI) is highly variable. The underlying pathophysiology of this is poorly understood, but inflammation is potentially an important factor. Microglia orchestrate many aspects of this response. Their activation can be studied in vivo using the positron emission tomography (PET) ligand [11C](R)PK11195 (PK). In this study, we investigate whether an inflammatory response to TBI persists, and whether this response relates to structural brain abnormalities and cognitive function.

Methods:

Ten patients, studied at least 11 months after moderate to severe TBI, underwent PK PET and structural magnetic resonance imaging (including diffusion tensor imaging). PK binding potentials were calculated in and around the site of focal brain damage, and in selected distant and subcortical brain regions. Standardized neuropsychological tests were administered.

Results:

PK binding was significantly raised in the thalami, putamen, occipital cortices, and posterior limb of the internal capsules after TBI. There was no increase in PK binding at the original site of focal brain injury. High PK binding in the thalamus was associated with more severe cognitive impairment, although binding was not correlated with either the time since the injury or the extent of structural brain damage.

Interpretation:

We demonstrate that increased microglial activation can be present up to 17 years after TBI. This suggests that TBI triggers a chronic inflammatory response particularly in subcortical regions. This highlights the importance of considering the response to TBI as evolving over time and suggests interventions may be beneficial for longer intervals after trauma than previously assumed. ANN NEUROL 2011;
Gestational vitamin D and the risk of multiple sclerosis in offspring
Authors: Mirzaei Fariba , Michels Karin B. , Munger Kassandra , O'Reilly Eilis , Chitnis Tanuja , Forman Michele R. , Giovannucci Edward , Rosner Bernard , Ascherio Alberto
Published: April 2011

Objective:

Vitamin D may have a protective role in the etiology of multiple sclerosis (MS), but the effect of gestational vitamin D on adult onset MS has not been studied.

Methods:

In 2001, 35,794 mothers of participants of the Nurses' Health Study II completed a questionnaire inquiring about their experiences and diet during pregnancy with their nurse daughters. We studied the association of maternal milk intake, maternal dietary vitamin D intake, and predicted maternal serum 25‐hydroxyvitamin D (25(OH)D) during pregnancy and their daughters' risk of developing MS.

Results:

MS was diagnosed in 199 women. The relative risk of MS was lower among women born to mothers with high milk or vitamin D intake during pregnancy. The multivariate adjusted rate ratio (RR) of MS was 0.62 (95% confidence interval [CI], 0.40–0.95; p trend = 0.001) for nurses whose mothers consumed 2 to 3 glasses of milk per day compared with those whose mothers consumed <3 glasses per month, and 0.57 (95% CI, 0.35–0.91; p trend = 0.002) for nurses with mothers in the highest quintile of dietary vitamin D intake compared with those in the lowest. The predicted 25(OH)D level in the pregnant mothers was also inversely associated with the risk of MS in their daughters. Comparing extreme quintiles, the adjusted RR was 0.59; (95% CI, 0.37–0.92; p trend = 0.002).

Interpretation:

Higher maternal milk and vitamin D intake during pregnancy may be associated with a lower risk of developing MS in offspring. ANN NEUROL 2011;
Effects of fossil fuel price fluctuations on electricity planning comprising renewable energy
Authors: Muis Z. A. , Hashim H. , Manan Z. A. , Douglas P. L.
Published: April 2011

Electricity generation mix in Malaysia largely relies on fossil fuel including coal, natural gas (NG), diesel and fuel oil. In the Ninth Malaysia Plan, the government aims to achieve 5% electricity generation mix from renewable energy (RE). Nevertheless, until now, RE contributes less than 1% of the national electricity generation mix. In spite of its emission benefits, NG prices volatility have encouraged calls for investments in RE. Unfortunately, NG price in Malaysia is highly subsidized, thereby making RE implementation unattractive. This article addresses the impact of NG price (with and without subsidies) on RE‐integrated electricity generation in Malaysia. The results show that a small increment in NG price will not affect the selection of RE source for electricity generation. If RE electricity generation is chosen, it will slightly increase the cost of electricity (COE) by 2.2 cents/kWh. Without NG subsidies, this cost can be translated to an additional 3 cents/kWh of COE. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Development of combined fouling model in a membrane bioreactor
Authors: Kim M. J. , Yoo G. Y. , Yoo C. K.
Published: April 2011

Membrane bioreactor (MBR) system has recently become very important in wastewater treatment. However, membrane capacity during the filtration process is reduced by fouling, which is the deposition or adsorption of particles on the membrane surface or inside of the pores. For an efficient operation of MBR system, prediction of MBR fouling progress and determination of proper membrane chemical cleaning interval is necessary. Until now, four blocking models, which are complete blocking, intermediate blocking, cake filtration, and standard blocking, have typically been used to describe and predict the MBR fouling. In this study, a new combined membrane fouling model, based on the four constant flowrate blocking models, is developed to explain the combined effects of the different fouling mechanisms. This model is assumed to be more accurate in determining the chemical cleaning interval by considering variation of dominant fouling mechanisms in the filtration process. The combined fouling model is applied to data sets from a pilot‐scale MBR for monitoring the variations of dominant fouling stage. By checking temporal variations of root mean square error (RMSE) values from fitting trans‐membrane pressure data to four constant flowrate blocking models, the dominant fouling mechanism by each fouling stage is determined. In particular, the fouling prediction result by the new combined model of three fouling mechanisms, which are complete blocking, cake filtration, and intermediate blocking, excluding the standard blocking model has better predictive accuracy than the combined model of four mechanisms, which remarkably reduced the RMSE from 10.48 to 1.73. On the basis of the improvement, the new combined model with three mechanisms has the potential to predict MBR fouling process and to determine the optimum interval for membrane chemical cleaning. Our results would contribute the economic operation of MBR plants by suggesting the appropriate membrane cleaning interval with the filtration capacity maintained at optimal level. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.