bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymptomatic cardiovascular manifestations in diabetes mellitus: Left ventricular diastolic dysfunction and silent myocardial ischemia
Authors: Seferovic-Mitrovic Jelena , Lalic Nebojsa , Vujisic-Tesic Bosiljka , Lalic Katarina , Jotic Aleksandra , Ristic Arsen , Giga Vojislav , Tesic Milorad , Milic Natasa , Lukic Ljiljana , Milicic Tanja , Singh Sandra , Seferovic Petar
Published: November 2011

Introduction. Several cardiovascular manifestations in patients with diabetes
may be asymptomatic. Left ventricular diastolic dysfunction (LVDD) is
considered to be the earliest metabolic myocardial lesion in these patients,
and can be diagnosed with tissue Doppler echocardiography. Silent myocardial
ischemia (SMI) is a characteristic and frequently described form of ischemic
heart disease in patients with diabetes. Objective. The aim of the study was
to assess the prevalence of LVDD and SMI in patients with type 2 diabetes, as
well as to compare demographic, clinical, and metabolic data among defined
groups (patients with LVDD, patients with SMI and patients with type 2
diabetes, without LVDD and SMI). Methods. We investigated 104 type 2 diabetic
patients (mean age 55.4?9.1 years, 64.4% males) with normal blood pressure,
prehypertension and arterial hypertension stage I. Study design included
basic laboratory assessment and cardiological workup (transthoracic
echocardiography and tissue Doppler, as well as the exercise stress
echocardiography). Results. LVDD was diagnosed in twelve patients (11.5%),
while SMI was revealed in six patients (5.8%). Less patients with LVDD were
using metformin, in comparison to other two groups (?2 =12.152; p=0.002).
Values of HDL cholesterol (F=4.515; p=0.013) and apolipoprotein A1 (F=5.128;
p= 0.008) were significantly higher in patients with LVDD. Conclusion. The
study confirmed asymptomatic cardiovascular complications in 17.3% patients
with type 2 diabetes.
Urethral reconstruction in severe hypospadias using buccal mucosa graft and penile skin flap
Authors: Majstorovic Marko , Bizic Marta , Kojovic Vladimir , Stojanovic Borko , Krstic Zoran , Djordjevic Miroslav
Published: November 2011

Introduction. Hypospadias represents the most frequent penile anomaly. The
most challenging part of hypospadias surgery is urethral reconstruction. Many
various tissues are used (local skin flaps, bladder mucosa grafts, buccal
mucosa grafts etc.) for the reconstruction of the neourethra. Objective. Our
aim was to evaluate advantages and disadvantages of combined buccal mucosa
graft and penile skin flap in urethral reconstruction in severe hypospadias
repair. Methods. Between December 2005 and August 2009, 48 patients with
severe hypospadias, aged from nine months to 12 years (mean age 23 months)
underwent surgery. Thirty-four (71%) had penoscrotal and 14 (29%) scrotal
hypospadias. Ventral penile curvature was present in all cases, and was
corrected by incision of the short urethral plate. Urethroplasty was
performed using a buccal mucosa graft combined with dorsal penile skin flap.
Results. Mean follow-up was 22 months (range from 9 months to 3 years).
Satisfactory functional and aesthetic results were achieved in 40 (83%)
patients. Fistula was noted in six cases and was solved by minor revision.
Urethral stenosis in two cases was resolved by simple dilatation. Conclusion.
Urethral reconstruction using the buccal mucosa graft and dorsal penile skin
flap in severe hypospadias repair could be the method of choice. Using this
technique, single stage urethral reconstruction is possible with satisfactory
esthetical and functional results.
Physical therapy in the treatment of stress urinary incontinence
Authors: Parezanovic-Ilic Katarina , Jeremic Branislav , Mladenovic-Segedi Ljiljana , Arsenijevic Slobodan , Jevtic Milorad
Published: November 2011

Introduction. Stress urinary incontinence (SUI) is an involuntary release of
urine through the urethra during the increase of abdominal pressure in the
absence of m. detrusor contraction. The exercise of pelvic floor muscles is
recommended as the first line of cure. It is the least invasive and the only
method without any undesirable side effects, which leads to either
improvement or complete cure of SUI in 80-85% of cases. Objective. The aim of
this study was to establish whether the strengthening of pelvic floor muscles
using proprioceptive neural facilitation (PNF) spiral dynamic technique was
more efficient in comparison to classical Kegel exercise. Methods. The
research was carried out at the Centre for Physical Medicine and
Rehabilitation, Clinical Centre Kragujevac. Sixty-six female patients with
the symptoms of SUI were monitored in the period of two years. Thirty-four
patients did pelvic floor muscle exercises twice a day, in the morning and in
the evening, with 15-20 contractions. Thirty-two patients used PNF spiral
dynamic technique for strengthening pelvic floor muscles. The patients who
used the spiral dynamic technique also did some exercises from the program;
they exercised twice a day, in the morning and in the evening, following the
prescribed schedule. Treatment outcome was assessed by measuring the pelvic
floor muscles by a vaginal dynamometer. Results. The values of the pelvic
floor muscle force that were measured using the vaginal dynamometer in both
examined groups (PNF spiral dynamic technique or Kegel exercise) were
statistically significantly higher after the implemented exercise program
(t-test; p=0.000). No statistically significant difference in pelvic floor
muscle values was found between the patients who applied PNF spiral dynamic
technique and those who did Kegel exercise either before or after the
exercise (two-factor analysis of variance with repeated measurements, factor
of exercise type; p=0.899). Conclusion. Strengthening of pelvic floor muscles
by exercises results in a significant increase of pelvic floor muscle
strength and reduction of SUI symptoms, regardless of the used exercise
program, PNF spiral dynamic technique or Kegel exercise program.
Influence of air pollution on birth weight
Authors: Stankovic Aleksandra , Mitrovic Vladimir , Zivadinovic Radomir
Published: November 2011

Introduction. Epidemiological studies point out that exposure to air
pollution during pregnancy is a risk for low birth weight. Objective. The aim
of this study was to evaluate the effects of outdoor and indoor air pollution
on the occurrence of low birth weight. Methods. The measurement of outdoor
air pollutants, sulphur dioxide and black smoke was carried out daily at the
Institute for Public Healthcare of Nis at two measuring locations, in Nis and
Niska Banja during 2003. Subjects were 367 pregnant women, nonsmokers and who
were not profesionally exposed to air pollution. Data on exposure to source
of indoor air pollution (passive smoking and mode of heating) was determined
on the basis of a questionnaire. Data on the characteristics of newborns
were taken from the register of Obstetrics and Gyanecology Clinic of Nis.
Results. We determined that exposure of pregnant women to outdoor air
pollution and wood heating systems had influence on the occurence of low
birth weight. Exposure to passive smoking had no influence on neonatal low
birth weight. Conclusion. Exposure of pregnant women to outdoor and indoor
air pollutants can have negative influence on the occurrence of low birth
weight.
Nonspecific defense mechanisms in dogs during experimental staphylococcal infection
Authors: Andonova Maria , Dimitrova Dimitritchka , Borissov I.
Published: November 2011

The aim of our study was to evaluate nonspecific defense mechanisms
(phagocytosis and acute phase response) in dogs during an experimental
infection caused by subcutaneous application of Staphylococcus aureus (1x108
CFU/mL). The neutrophils phagocytosis (evaluated by fluorescein
isothiocyanate labeled Staphylococcus aureus) is activated at 48 h and the
phagocytic number remained high at the 72-nd h of infection. During the early
stage of the infection process (between the 2-nd and 24-th h) the absolute
segmented neutrophil count, the absolute band count, band-neutrophyl ratio,
tend to have high sensitivity, whereas an abnormal leukocyte count is
registered at 48 h. Fibrinogen increase is registered the earliest (at 24-th
h). Its concentrations remain high till the end of the study. The changes in
the blood protein profiles show that the ?2-globulin fraction rises at the
48-th and 72-nd h. Albumin was significantly lower at 72 h compared to the
baseline values. There are no statistically significant changes in the total
protein, A/G ratio and sialic acid, which we determined. The obtained data
about the red blood cell parameters shows that Staphylococcus aureus induces
a moderate anaemia when applied in dogs. Deviations are also registered in
the mean corpuscular hemoglobin, while the other red blood cell indices -
mean corpuscular hemoglobin concentration and mean corpuscular volume, are
within normal reference ranges. We conclude that it is always better to
combine immunological, hematological and biochemical indices. The key is to
choose tests that are frequently used and to ensure more rapid information
about the infectious process.
Identification of serotonergic (5HT1A-type) receptors in broiler small intestine by application of serotonin and its agonists and antagonists
Authors: Mujezinovic Indira , Cupic Vitomir , Smajlovic Ahmed , Muminovic Mehmed
Published: November 2011

Serotonin or 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter
synthesised from L-tryptophan in serotonergic neurons and enterochromaffin
cells of the gastrointestinal tract. This neurotransmitter is widely
distributed in the animal and plant kingdom and regulates some central and
peripheral functions through several types of specific serotonergic (5-HT)
receptors. Since it is known that the effect of serotonin, especially in
pathological conditions, is very important, we believe that determining the
types of receptors for this substance would make it possible to use their
agonist or antagonists, which would undoubtedly enhance the pharmacotherapy
of functional disruption of the small intestine in broilers. Investigations
were carried out on isolated smooth muscle strips of the circular and
longitudinal layer of the broiler small intestine (strip dimension 3-4 mm x 2
cm). The muscle strips were placed in an isolated organ bath. The mechanical
activity of the preparations was recorded via an isotonic force transducer
coupled to a pen recorder. This was done following the addition of serotonin
(nonselective 5-HT agonist), 8-OH-DPAT (selective 5-HT1A agonist) and
spiroxatrin (selective 5-HT1A antagonist). The sensitivity of the tissues to
acetylcholine was tested before starting the experiments. Using the obtained
results, it can be concluded that 5HT1A type receptors are present in smooth
muscles of the broiler small intestine, duodenum and ileum, especially in the
longitudinal smooth muscle layer which reacted with contractions even to low
serotonin concentration (10-6), but not in the jejunum.
Investigations of variability of morphometric characteristics in Busa and Gatacko cattle in order to preserve autochthonous genome
Authors: Rogic Biljana , Vazic Bozo , Jovanovic Slobodan , Stamenkovic-Radak Marina , Savic Mila , Ravic Ivica
Published: November 2011

With the objective of studying and protecting genomes of autochthonous breeds
of cattle, investigations were performed of the variability of morphometric
characteristics of the autochthonous breeds Busa and Gatacko cattle, as well
as a retrospective analysis of the development of the examined populations.
The investigations covered 97 cows, specifically 22 head of western
Herzegovina Busa cattle, 24 head of eastern Herzegovina Busa cattle, and 51
head of Gatacko cattle. Morphometric measurements were examined: height at
withers, body length, foot circumference, and chest girth. The obtained data
were processed statistically, and variability was established using simple
variance analysis with an unequal number of repetitions. The significance of
the obtained differences from the three investigated localities was tested
using the F test and t-test. A significant degree of variability was
established for the morphological characteristics within the examined
populations, as well as between the populations. The established differences
are primarily a result of the influence of different natural conditions and
breeding conditions, as well as the genome share of Alpine cattle, with which
the Busa has been crossbred.
Injuries and noninfective health disorders of veterinarians
Authors: Vucinic Marijana
Published: November 2011

In professional and scientific journals there are many published results on
different prevalence, patterns and risk factors of animal-related injuries
and occupational disorders among veterinarians. Veterinary medicine is
hazardous. Veterinarians work under uncomfortable and unsafe conditions not
only in animal housing units but also in their clinics, stations and
surgeries with wet and slippery floors. They work closely with animals.
Veterinarians are a high-risk group for significant injury from animal
contacts. Veterinarians perform procedures that cause the animal pain,
distress, and protective reactions of animals in different forms, such as
biting, kicking, scratching or other trauma from the animals. They are
exposed to different risk materials, equipment and many other risk factors
such as radiation, oncogenic viruses, sharp instruments, anaesthetics gases,
pesticides (insecticides), long working hours and occupational stressors.
Veterinarians work with unknown animals, unknown people and demanding
clients. Veterinarian are not only at increased risk of occupational diseases
and injuries but also at increased risk of death from workrelated injuries,
motor vehicle accidents, malignant diseases and suicide.
Selection Models in Accounting Research
Authors: Lennox Clive S. , Francis Jere R. , Wang Zitian
Published: November 2011

This study explains the challenges associated with the Heckman (1979) procedure to control for selection bias, assesses the quality of its application in accounting research, and offers guidance for better implementation of selection models. A survey of 75 recent accounting articles in leading journals reveals that many researchers implement the technique in a mechanical way with relatively little appreciation of important econometric issues and problems surrounding its use. Using empirical examples motivated by prior research, we illustrate that selection models are fragile and can yield quite literally any possible outcome in response to fairly minor changes in model specification. We conclude with guidance on how researchers can better implement selection models that will provide more convincing evidence on potential selection bias, including the need to justify model specifications and careful sensitivity analyses with respect to robustness and multicollinearity.

Data Availability: Data used are available from public sources identified in the study.
Customer-Base Concentration: Implications for Firm Performance and Capital Markets
Authors: Patatoukas Panos N.
Published: November 2011

This study investigates whether and how customer-base concentration affects supplier firm fundamentals and stock market valuation. I compile a comprehensive sample of supply chain relationships and develop a measure (CC) to capture the extent to which a supplier's customer base is concentrated. In contrast to the conventional view of customer-base concentration as an impediment to supplier firm performance, I document a positive contemporaneous association between CC and accounting rates of return, suggesting that efficiencies accrue to suppliers with concentrated customer bases. Consistent with a cause-and-effect link between customer-base concentration and supplier firm performance, analysis of intertemporal changes demonstrates that CC increases predict efficiency gains in the form of reduced operating expenses per dollar of sales and enhanced asset utilization. Using stock returns tests, I find that investors underreact to the implications of changes in customer-base concentration for future firm fundamentals when setting stock prices. A trading strategy that exploits investors' underreaction yields abnormal stock returns over the 30-year period studied.

JEL Classifications: M41; L25; G14.

Data Availability: Data are available from the sources indicated in the text.
What Cannot Be Said: Notes on Early French Wittgenstein Reception
Authors: Helgeson James
Published: November 2011

Although Wittgenstein's philosophy long went untranslated in France, he was not entirely unread. Yet the relatively minor impact of Wittgenstein in mid-century French-language philosophy stands in marked contrast to the centrality of Wittgenstinian themes in Anglo-American thinking. Early French writings on Wittgenstein, as well a colloquium on analytic philosophy held at Royaumont in 1958, are discussed, and explanations proposed for Wittgenstein's limited reception in France in the five decades following the publication of the Tractatus in 1921/22. Possible effects of Wittgenstein's quasi-absence from French discussion in the period on more recent theoretical reflection are briefly examined. It is suggested that Oxford philosophers of the 1950s, and in particular J.L. Austin, had a more immediate impact on French readers.
A 1HNMR-Based Metabonomics Study of Postmenopausal Osteoporosis and Intervention Effects of Er-Xian Decoction in Ovariectomized Rats
Authors: Xue Liming , Wang Yin , Liu Lei , Zhao Lu , Han Ting , Zhang Qiaoyan , Qin Luping
Published: November 2011

A metabonomics method using 1H nuclear magnetic resonance spectroscopy (1HNMR) was applied to obtain a systematic view of the development and progression of postmenopausal osteoporosis. Using partial least squares discriminant analysis (PLS-DA), 26 and 34 characteristic resonances were found respectively in urine and plasma of ovariectomized rats (Variable importance, VIP value ≥1.0), and the significant altered metabolites identified in the plasma and urine were 10 and 9, respectively. Changes in these metabolites were related to the pathways of lipid, energy and amino acid metabolism, some of which involved the oxidative system. The described method was also used to analyze the therapeutic effects of Er-Xian Decoction (EXD), a traditional Chinese medicine widely used in the clinical treatment of osteoporosis in China. The results showed that EXD administration could provide satisfactory effects on osteoporosis through partially regulating the perturbed pathways of lipid, energy and amino acid metabolism and improving the anti-oxidative ability.
Tasco®, a Product of Ascophyllum nodosum, Imparts Thermal Stress Tolerance in Caenorhabditis elegans
Authors: Kandasamy Saveetha , Fan Di , Sangha Jatinder Singh , Khan Wajahatullah , Evans Franklin , Critchley Alan T. , Prithiviraj Balakrishnan
Published: November 2011

Tasco®, a commercial product manufactured from the brown alga Ascophyllum nodosum, has been shown to impart thermal stress tolerance in animals. We investigated the physiological, biochemical and molecular bases of this induced thermal stress tolerance using the invertebrate animal model, Caenorhabiditis elegans. Tasco® water extract (TWE) at 300 µg/mL significantly enhanced thermal stress tolerance as well as extended the life span of C. elegans. The mean survival rate of the model animals under thermal stress (35 °C) treated with 300 µg/mL and 600 µg/mL TWE, respectively, was 68% and 71% higher than the control animals. However, the TWE treatments did not affect the nematode body length, fertility or the cellular localization of daf-16. On the contrary, TWE under thermal stress significantly increased the pharyngeal pumping rate in treated animals compared to the control. Treatment with TWE also showed differential protein expression profiles over control following 2D gel-electrophoresis analysis. Furthermore, TWE significantly altered the expression of at least 40 proteins under thermal stress; among these proteins 34 were up-regulated while six were down-regulated. Mass spectroscopy analysis of the proteins altered by TWE treatment revealed that these proteins were related to heat stress tolerance, energy metabolism and a muscle structure related protein. Among them heat shock proteins, superoxide dismutase, glutathione peroxidase, aldehyde dehydrogenase, saposin-like proteins 20, myosin regulatory light chain 1, cytochrome c oxidase RAS-like, GTP-binding protein RHO A, OS were significantly up-regulated, while eukaryotic translation initiation factor 5A-1 OS, 60S ribosomal protein L18 OS, peroxiredoxin protein 2 were down regulated by TWE treatment. These results were further validated by gene expression and reporter gene expression analyses. Overall results indicate that the water soluble components of Tasco® imparted thermal stress tolerance in the C. elegans by altering stress related biochemical pathways.
Clinical Response to Glycyrrhizinic Acid in Genital Infection Due to Human Papillomavirus and Low-Grade Squamous Intraepithelial Lesion
Authors: Valencia Marcelino Hernandez , Pacheco Adia Carrillo , Quijano Tomás Hernández , Girón Antonio Vargas , López Carlos Vargas
Published: November 2011

Human papilloma virus (HPV) can infect any of the mucosal areas of the body and cause cervical cancer. Until recently, no specific treatments were available for this condition; therefore, any damaged tissue had to be removed or destroyed, which may have presented obstetrical repercussions for some women. Recently, new drugs have been developed that have shown to be effective for the cure of HPV infection. Glycyrrhizinic acid (GA) has shown fewer side effects and its systemic use makes it possible to reach difficultto- treat lesions. The purpose of this study was to evaluate the clinical outcome of GA to eliminate the epithelial lesion and HPV. We carried out a longitudinal, descriptive study that included women of reproductive age who were diagnosed with HPV associated with low-grade squamous intraepithelial lesion (LSIL). Subjects began treatment based on GA using two routes of administration - systemic (oral) and topical (spray) - with assessments every month to determine the clinical changes of the lesions through colposcopy and Papanicolaou (Pap) smear. Simple statistics were used along with two-tailed Student’s t-test; P < 0.05 was considered statistically significant before and after treatment. There were 70 eligible patients, of whom 62 fulfilled the inclusion criteria. Age of subjects was 27.8 ± 9.5 years. At the time of the study, 100% of the patients had HPV infection, 40% were associated with LSIL, and only 16% used a barrier contraceptive (condom) method. Resolution was achieved in all patients from 4 weeks of treatment initiation and improvement was achieved in the majority of patients at 12 weeks (74%) (P < 0.001). However, there was persistence of LSIL in 27.7% of patients and only one patient progressed to cervical intraepithelial neoplasia (CIN) II. The use of GA proved to be effective in resolving clinical HPV lesions. For cervical lesions with epithelial changes (LSIL), treatment may be required for a longer period as with other drugs used for this infection, as well as monitoring for at least 1 year according to the natural evolution of the disease.
Iron Supplementation Reduces the Frequency and Severity of Breath-Holding Attacks in Non-Anaemic Children
Authors: Zehetner Anthony
Published: November 2011

Iron supplementation reduces the frequency and severity of breath-holding attacks (BHAs), particularly in children with iron deficiency. The issue of iron supplementation is less clear for Westernized children with BHAs who present to an outpatient community clinic and are not iron-deficient. This is the first reported case series of iron-replete children with frequent and disabling breath-holding attacks who have responded to a course of oral iron supplementation. This intervention is safe, improves quality of life for both child and carer, and is significantly cost-effective in terms of health resource utilization.
The Use of Molecular Profiling for Diagnosis and Research in Non-Hodgkin's Lymphoma
Authors: Piris Miguel Angel
Published: November 2011

Molecular profiling facilitates the understanding of the genetic processes underlying the development of cancer, and makes it possible to use specific signatures to prognosticate clinical outcome and to predict response to specific treatments. There has been a great increase in the availability of tools for exploring genetic abnormalities in cancer cells, which have allowed a more comprehensive characterization of the mutations, translocations, and copy-number variations that may affect the development of cancer or therapy response. An improved understanding of the molecular basis of cancer is helping also in the identification of new molecular targets for therapy.
Safety and Efficacy of Intravenous Clevidipine for the Perioperative Control of Acute Hypertension
Authors: Murphy Claire V. , Brower Kristin I.
Published: November 2011

Clevidipine is a third generation dihydropyridine calcium channel blocker recently approved by the Food and Drug Administration and is an emerging option for management of perioperative hypertension. This intravenous medication has several properties that may be advantageous when rapid and safe blood pressure control is required, including fast onset, short duration of action and the lack of renal or hepatic metabolism. Clevidipine has been demonstrated to be safe and efficacious for the management of perioperative hypertension in the cardiac surgery population, with minimal excursions outside of the target blood pressure range. Despite the fact that clevidipine does have certain advantages over alternative agents, it has some distinct limitations associated with its use, including higher associated costs and limited data in non-cardiac surgery patients. While clevidipine may serve as an additional option, further research is required to fully establish the role of clevidipine in the management of perioperative hypertension.
Falls, Older Adults, and the Impact of the Neighborhood Environment
Authors: Chippendale Tracy , Bear-Lehman Jane
Published: November 2011

Almost half of falls occur outdoors; yet, the emphasis in fall prevention has been on intrinsic factors and the indoor environment. In this article we argue that the neighborhood environment and its impact on falls warrants further attention. Occupational therapy is best suited to address these issues in collaboration with urban planners and public health professionals. Both practice and policy changes are suggested to meet the health and wellness needs of community-dwelling older adults going forward.
Manualization of Occupational Therapy Interventions: Illustrations From the Pressure Ulcer Prevention Research Program
Authors: Blanche Erna Imperatore , Fogelberg Donald , Diaz Jesus , Carlson Mike , Clark Florence
Published: November 2011

The manualization of a complex occupational therapy intervention is a crucial step in ensuring treatment fidelity for both clinical application and research purposes. Toward the latter end, intervention manuals are essential for ensuring trustworthiness and replicability of randomized controlled trials that aim to provide evidence of the effectiveness of occupational therapy. In this article, we review the literature on the process of intervention manualization. We then illustrate the prescribed steps through our experience in implementing the University of Southern California/Rancho Los Amigos National Rehabilitation Center’s collaborative Pressure Ulcer Prevention Project. In this research program, qualitative research provided the initial foundation for manualization of a multifaceted occupational therapy intervention designed to reduce the incidence of medically serious pressure ulcers in adults with spinal cord injury.
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide
Authors: Battle M. O. , Severinghaus J. P. , Sofen E. D. , Plotkin D. , Orsi A. J. , Aydin M. , Montzka S. A. , Sowers T. , Tans P. P.
Published: November 2011

Abstract. We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow firn, gravitational enrichment of heavy species throughout the diffusive column in general agreement with theoretical expectations, a ~10 m thick lock-in zone beginning at ~67 m, and a total firn thickness consistent with predictions of Kaspers et al. (2004). Our modeling work shows that the air has an age spread (spectral width) of 4.8 yr for CO2 at the firn-ice transition. We also find that advection of firn air due to the 22 cm yr−1 ice-equivalent accumulation rate has a minor impact on firn air composition, causing changes that are comparable to other modeling uncertainties and intrinsic sample variability. Furthermore, estimates of Δage (the gas age/ice age difference) at WAIS-D appear to be largely unaffected by bubble closure above the lock-in zone. Within the lock-in zone, small gas species and their isotopes show evidence of size-dependent fractionation due to permeation through the ice lattice with a size threshold of 0.36 nm, as at other sites. We also see an unequivocal and unprecedented signal of oxygen isotope fractionation within the lock-in zone, which we interpret as the mass-dependent expression of a size-dependent fractionation process.
Cloud condensation nuclei (CCN) from fresh and aged air pollution in the megacity region of Beijing
Authors: Gunthe S. S. , Rose D. , Su H. , Garland R. M. , Achtert P. , Nowak A. , Wiedensohler A. , Kuwata M. , Takegawa N. , Kondo Y. , Hu M. , Shao M. , Zhu T. , Andreae M. O. , Pöschl U.
Published: November 2011

Abstract. Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. CCN properties were measured and characterized during the CAREBeijing-2006 campaign at a regional site south of the megacity of Beijing, China. Size-resolved CCN efficiency spectra recorded for a supersaturation range of S=0.07% to 0.86% yielded average activation diameters in the range of 190 nm to 45 nm. The corresponding effective hygroscopicity parameters (κ) exhibited a strong size dependence ranging from ~0.25 in the Aitken size range to ~0.45 in the accumulation size range. The campaign average value (κ =0.3 ± 0.1) was similar to the values observed and modeled for other populated continental regions. The hygroscopicity parameters derived from the CCN measurements were consistent with chemical composition data recorded by an aerosol mass spectrometer (AMS) and thermo-optical measurements of apparent elemental and organic carbon (EC and OC). The CCN hygroscopicity and its size dependence could be parameterized as a function of only AMS based organic and inorganic mass fractions (forg, finorg) using the simple mixing rule κp ≈ 0.1 · forg + 0.7 · finorg. When the measured air masses originated from the north and passed rapidly over the center of Beijing (fresh city pollution), the average particle hygroscopicity was reduced (κ = 0.2 ± 0.1), which is consistent with enhanced mass fractions of organic compounds (~50%) and EC (~30%) in the fine particulate matter (PM1). Moreover, substantial fractions of externally mixed weakly CCN-active particles were observed at low supersaturation (S=0.07%), which can be explained by the presence of freshly emitted soot particles with very low hygroscopicity (κ < 0.1). Particles in stagnant air from the industrialized region south of Beijing (aged regional pollution) were on average larger and more hygroscopic, which is consistent with enhanced mass fractions (~60%) of soluble inorganic ions (mostly sulfate, ammonium, and nitrate). Accordingly, the number concentration of CCN in aged air from the megacity region was higher than in fresh city outflow ((2.5–9.9) × 103 cm−3 vs. (0.4–8.3) × 103 cm−3 for S=0.07–0.86%) although the total aerosol particle number concentration was lower (1.2 × 104 cm−3 vs. 2.3 × 104 cm−3). A comparison with related studies suggests that the fresh outflow from Chinese urban centers generally may contain more, but smaller and less hygroscopic aerosol particles and thus fewer CCN than the aged outflow from megacity regions.
Illustrating the benefit of using hourly monitoring data on secondary inorganic aerosol and its precursors for model evaluation
Authors: Schaap M. , Otjes R. P. , Weijers E. P.
Published: November 2011

Abstract. Secondary inorganic aerosol, most notably ammonium nitrate and ammonium sulphate, is an important contributor to ambient particulate mass and provides a means for long range transport of acidifying components. The modelling of the formation and fate of these components is challenging. Especially, the formation of the semi-volatile ammonium nitrate is strongly dependent on ambient conditions and the precursor concentrations. For the first time an hourly artefact free data set from the MARGA instrument is available for the period of a full year (1 August 2007 to 1 August 2008) at Cabauw, the Netherlands. This data set is used to verify the results of the LOTOS-EUROS model. The comparison showed that the model underestimates the SIA levels. Closer inspection revealed that base line values appear well estimated for ammonium and sulphate and that the underestimation predominantly takes place at the peak concentrations. For nitrate the variability towards high concentrations is much better captured, however, a systematic relative underestimation was found. The model is able to reproduce many features of the intra-day variability observed for SIA. Although the model captures the seasonal and average diurnal variation of the SIA components, the modelled variability for the nitrate precursor gas nitric acid is much too large. It was found that the thermodynamic equilibrium module produces a too stable ammonium nitrate in winter and during night time in summer, whereas during the daytime in summer it is too unstable. We recommend to improve the model by verification of the equilibrium module, inclusion of coarse mode nitrate and to address the processes concerning SIA formation combined with a detailed analysis of the data set at hand. The benefit of the hourly data with both particulate and gas phase concentrations is illustrated and a continuation of these measurements may prove to be very useful in future model evaluation and improvement studies. Based on our findings we propose to implement a monitoring strategy using three levels of detail within the Netherlands.
Transport and mixing patterns over Central California during the Carbonaceous Aerosol and Radiative Effects Study (CARES)
Authors: Fast J. D. , Gustafson W. I. , Berg L. K. , Shaw W. J. , Pekour M. , Shrivastava M. , Barnard J. C. , Ferrare R. A. , Hostetler C. A. , Hair J. A. , Erickson M. , Jobson B. T. , Flowers B. , Dubey M. K. , Springston S. , Pierce R. B. , Dolislager L. , Pederson J. , Zaveri R. A.
Published: November 2011

Abstract. We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scales flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin Valley, were relatively low. Aerosol layering in the free troposphere was observed during the morning by an airborne Lidar. WF-Chem forecasts showed that mountain venting processes contributed to aged pollutants aloft in the valley atmosphere that is then entrained into the growing boundary layer the subsequent day.
The direct effect of aerosols on solar radiation over the broader Mediterranean basin
Authors: Papadimas C. D. , Hatzianastassiou N. , Matsoukas C. , Kanakidou M. , Mihalopoulos N. , Vardavas I.
Published: November 2011

Abstract. For the first time, the direct radiative effect (DRE) of aerosols on solar radiation is computed over the entire Mediterranean basin, one of the most climatically sensitive world regions, by using a deterministic spectral radiation transfer model (RTM). The DRE effects on the outgoing shortwave radiation at the top of atmosphere (TOA), DRETOA, on the absorption of solar radiation in the atmospheric column, DREatm, and on the downward and absorbed surface solar radiation (SSR), DREsurf and DREnetsurf, respectively, are computed separately. The model uses input data for the period 2000–2007 for various surface and atmospheric parameters, taken from satellite (International Satellite Cloud Climatology Project, ISCCP-D2), Global Reanalysis projects (National Centers for Environmental Prediction – National Center for Atmospheric Research, NCEP/NCAR), and other global databases. The spectral aerosol optical properties (aerosol optical depth, AOD, asymmetry parameter, gaer and single scattering albedo, ωaer), are taken from the MODerate resolution Imaging Spectroradiometer (MODIS) of NASA (National Aeronautics and Space Administration) and they are Supplemented by the Global Aerosol Data Set (GADS). The model SSR fluxes have been successfully validated against measurements from 80 surface stations of the Global Energy Balance Archive (GEBA) covering the period 2000–2007. A planetary cooling is found above the Mediterranean on an annual basis (regional mean DRETOA = −2.4 Wm−2). Though planetary cooling is found over most of the region, up to −7 Wm−2, large positive DRETOA values (up to +25 Wm−2) are found over North Africa, indicating a strong planetary warming, as well as over the Alps (+0.5 Wm−2). Aerosols are found to increase the absorption of solar radiation in the atmospheric column over the region (DREatm = +11.1 Wm−2) and to decrease SSR (DREsurf = −16.5 Wm−2 and DREnetsurf −13.5 Wm−2) inducing thus significant atmospheric warming and surface radiative cooling. The calculated seasonal and monthly DREs are even larger, reaching −25.4 Wm−2 (for DREsurf). Sensitivity tests show that regional DREs are most sensitive to ωaer and secondarily to AOD, showing a quasi-linear dependence to these aerosol parameters.
Circular depolarization ratios of single water droplets and finite ice circular cylinders: a modeling study
Authors: Nicolet M. , Schnaiter M. , Stetzer O.
Published: November 2011

Abstract. Computations of the phase matrix elements for single water droplets and ice crystals in fixed orientations are presented to determine if circular depolarization δ±C is more accurate than linear depolarization for phase discrimination. T-matrix simulations were performed to calculate right-handed and left-handed circular depolarization ratios δ+C, respectively δ−C and to compare them with linear ones. Ice crystals are assumed to have a circular cylindrical shape where their surface-equivalent diameters range up to 5 μm. The circular depolarization ratios of ice particles were generally higher than linear depolarization and depended mostly on the particle orientation as well as their sizes. The fraction of non-detectable ice crystals (δ < 0.05) was smaller considering a circular polarized light source, reaching 4.5%. However, water droplets also depolarized light circularly for scattering angles smaller than 179° and size parameters smaller than 6 at side- and backscattering regions. Differentiation between ice crystals and water droplets might be difficult for experiments performing at backscattering angles which deviate from 180° unlike lidar applications. If the absence of the liquid phase is confirmed, the use of circular depolarization in single particle detection is more sensitive and less affected by particle orientation.
Atmospheric chemistry and physics in the atmosphere of a developed megacity (London): an overview of the REPARTEE experiment and its conclusions
Authors: Harrison R. M. , Dall'Osto M. , Beddows D. C. S. , Thorpe A. J. , Bloss W. J. , Allan J. D. , Coe H. , Dorsey J. R. , Gallagher M. , Martin C. , Whitehead J. , Williams P. I. , Jones R. L. , Langridge J. M. , Benton A. K. , Ball S. M. , Langford B. , Hewitt C. N. , Davison B. , Martin D. , Petersson K. , Henshaw S. J. , White I. R. , Shallcross D. E. , Barlow J. F. , Dunbar T. , Davies F. , Nemitz E. , Phillips G. J. , Helfter C. , Di Marco C. F. , Smith S.
Published: November 2011

Abstract. The Regents Park and Tower Environmental Experiment (REPARTEE) comprised two campaigns in London in October 2006 and October/November 2007. The experiment design involved measurements at a heavily trafficked roadside site, two urban background sites and an elevated site at 160–190 m above ground on the BT Tower, supplemented in the second campaign by Doppler lidar measurements of atmospheric vertical structure. A wide range of measurements of airborne particle physical metrics and chemical composition were made as well as measurements of a considerable range of gas phase species and the fluxes of both particulate and gas phase substances. Significant findings include (a) demonstration of the evaporation of traffic-generated nanoparticles during both horizontal and vertical atmospheric transport; (b) generation of a large base of information on the fluxes of nanoparticles, accumulation mode particles and specific chemical components of the aerosol and a range of gas phase species, as well as the elucidation of key processes and comparison with emissions inventories; (c) quantification of vertical gradients in selected aerosol and trace gas species which has demonstrated the important role of regional transport in influencing concentrations of sulphate, nitrate and secondary organic compounds within the atmosphere of London; (d) generation of new data on the atmospheric structure and turbulence above London, including the estimation of mixed layer depths; (e) provision of new data on trace gas dispersion in the urban atmosphere through the release of purposeful tracers; (f) the determination of spatial differences in aerosol particle size distributions and their interpretation in terms of sources and physico-chemical transformations; (g) studies of the nocturnal oxidation of nitrogen oxides and of the diurnal behaviour of nitrate aerosol in the urban atmosphere, and (h) new information on the chemical composition and source apportionment of particulate matter size fractions in the atmosphere of London derived both from bulk chemical analysis and aerosol mass spectrometry with two instrument types.
Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink
Authors: Lohila A. , Minkkinen K. , Aurela M. , Tuovinen J.-P. , Penttilä T. , Ojanen P. , Laurila T.
Published: November 2011

Abstract. Drainage for forestry purposes increases the depth of the oxic peat layer and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) change: due to the accelerated decomposition of peat in the presence of oxygen, drained peatlands are generally considered to lose peat carbon (C). We measured CO2 exchange with the eddy covariance (EC) method above a drained nutrient-poor peatland forest in southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net CO2 uptake from the atmosphere. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1) and a small source of N2O (0.10 g N2O m−2 yr−1). Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (175 ± 35 g C m−2) was significantly lower than the accumulation observed by the flux measurement (240 ± 30 g C m−2), about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown by EC measurements to occur in a forestry-drained peatland. Our results suggest that forestry-drainage may significantly increase the CO2 uptake rate of nutrient-poor peatland ecosystems.
A model study on the sensitivity of surface ocean CO2 pressure with respect to the CO2 gas exchange rate
Authors: Landschützer P. , Tjiputra J. F. , Assmann K. , Heinze C.
Published: November 2011

Abstract. Rising CO2 concentrations in the atmosphere and a changing climate are expected to alter the air-sea CO2 flux through changes in the respective control factors for gas exchange. In this study we determine the sensitivity of the CO2 fluxes on the gas transfer velocity using the MICOM-HAMOCC isopycnic carbon cycle model. The monthly generated MICOM-HAMOCC output data are suitable to investigate seasonal variabilities concerning the exchange of CO2. In a series of 3 sensitivity runs the wind dependent gas exchange rate is increased by 44%, both in the northern and southern westerly regions, as well as in the equatorial area to investigate the effect of regional variations of the gas transfer rate on the air-sea fluxes and the distribution of the ocean surface pCO2. For the period between 1948–2009, the results show that locally increasing gas transfer rates do not play an important role concerning the global uptake of carbon from the atmosphere. While effects on a global and annual scale are low, the regional and intra-annual variability shows remarkable variations in the gas fluxes and the surface pCO2. An accurate quantification of the variable gas transfer velocity therefore provides a potential source to enhance model predictions over small spatial and temporal scales and to successfully reconcile model results on surface pCO2 and air-sea CO2 fluxes with observations.