bluuebunny/crossref_metadata_2025 huggingface dataset:
Usefulness of Polymerase Chain Reaction to Supplement Field Microscopy in a Pre-Selected Population with a High Probability of Malaria Infections
Authors: Gunasekera W. M. Kumudunayana T. de A. W. , Abeyasinghe Rabindra R. , Premawansa Sunil , Fernando S. Deepika
Published: July 2011

This study determines the use of nested PCR as a diagnostic tool to supplement field microscopy in symptomatic individuals suspected of being positive for malaria, and it explores its role in active case detection to identify asymptomatic parasite carriers. In symptomatic individuals, compared with PCR, microscopy had a sensitivity of 86.6% (95% confidence interval [CI] = 77.8–92.4) and specificity of 100% (95% CI = 96.9–100). During active case detection, two asymptomatic persons were diagnosed as having vivax malaria by polymerase chain reaction (PCR) but not microscopy. Currently, PCR is being carried out in Sri Lanka only for population surveys to estimate the hidden reservoir of malaria. Based on the results of this study and because of cost considerations, pooled PCR will be used in the future to screen samples from clinically suspected foci to increase the proportion of malaria cases detected. This strategy will assist the success of the malaria elimination program in Sri Lanka.
Distribution and Phylogenetic Comparisons of a Novel Mosquito Flavivirus Sequence Present in Culex tarsalis Mosquitoes from Western Canada with Viruses Isolated in California and Colorado
Authors: Tyler Shaun , Bolling Bethany G. , Blair Carol D. , Brault Aaron C. , Pabbaraju Kanti , Armijos M. Veronica , Clark David C. , Calisher Charles H. , Drebot Michael A.
Published: July 2011

In a previous study, a new flavivirus genome sequence was identified in Culex tarsalis mosquitoes obtained in Alberta, Canada and was shown to be genetically related to but distinct from members of the insect-specific flaviviruses. Nonstructural protein 5–encoding sequences amplified from Cx. tarsalis pools from western Canada have shown a high similarity to genome sequences of novel flaviviruses isolated from mosquitoes in California and Colorado. Despite wide distribution of this virus, designated Calbertado virus, strains demonstrate a high degree of nonstructural protein 5 nucleotide (> 90%) and amino acid (> 97%) identity. The ecology and geographic range of Calbertado virus warrants further study because it may potentially influence transmission of mosquito-borne flaviviruses, including important human pathogens such as West Nile and Saint Louis encephalitis viruses.
Contribution of Dengue Fever to the Burden of Acute Febrile Illnesses in Papua New Guinea: An Age-Specific Prospective Study
Authors: Senn Nicolas , Luang-Suarkia Dagwin , Manong Doris , Siba Peter Max , Hannan McBride William John
Published: July 2011

Malaria is a major contributor to the burden of febrile illnesses in Papua New Guinea (PNG). Dengue fever (DF) is likely to contribute; however, its epidemiology in PNG is poorly understood. We performed a prospective age-stratified study in outpatient clinics investigating the prevalence of DF; 578 patients were enrolled, and 317 patients with a negative rapid diagnostic test (RDT) for malaria were tested for dengue. Malaria was confirmed in 52% (301/578, 95% confidence interval [CI] = 48–56%), DF was diagnosed in 8% (46/578, 95% CI = 6–10%), and 40% (95% CI = 36–44%) had neither diagnosis. Among the 317 malaria RDT-negative patients, 14% (45/317, 95% CI = 10–18%) had DF. The seroprevalence of dengue immunoglobulin G (IgG) was 83% (204/247, 95% CI = 78–87%), and no dengue hemorrhagic fever was seen. This study provides good evidence for the first time that DF is common in PNG and is responsible for 8% of fever episodes. The common occurrence of DF in a population with presumed previous exposure to dengue is an important observation.
Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine against Malaria and Anemia in Pregnant Women
Authors: Wilson Nana O. , Ceesay Fatou K. , Obed Samuel A. , Adjei Andrew A. , Gyasi Richard K. , Rodney Patricia , Ndjakani Yassa , Anderson Winston A. , Lucchi Naomi W. , Stiles Jonathan K.
Published: July 2011

The effectiveness of intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) against malaria and anemia is unclear because of the spread of SP-resistant Plasmodium falciparum. This study evaluates the effectiveness of IPTp-SP among pregnant women attending the antenatal clinic at Korle-Bu Teaching Hospital in Accra, Ghana. A cross-sectional study comparing malaria and anemia prevalence among pregnant women using IPTp-SP with non-IPTp-SP users was conducted during June–August 2009. A total of 363 pregnant women (202 of IPTp users and 161 non-IPTp users) were recruited. A total of 15.3% of IPTp users had malaria compared with 44.7% of non-IPTp users (P < 0.001). A total of 58.4% of non-IPTp users were anemic compared with 22.8% of IPTp users (P < 0.001). When we controlled for other variables, the difference in the prevalence of malaria (odds ratio = 0.18, 95% confidence interval = 0.08–0.37) and anemia (odds ratio = 0.20, 95% confidence interval = 0.12–0.34) remained significant. The recommended IPTp-SP regimen is useful in preventing malaria and anemia among pregnant women in Ghana.
Use of an Innovative, Affordable, and Open-Source Short Message Service–Based Tool to Monitor Malaria in Remote Areas of Uganda
Authors: Asiimwe Caroline , Gelvin David , Lee Evan , Amor Yanis Ben , Quinto Ebony , Katureebe Charles , Sundaram Lakshmi , Bell David , Berg Matt
Published: July 2011

Quality health management requires timely and accurate data, and paper-based reporting does not fill this role adequately. The introduction of malaria rapid diagnostic tests and the availability of wireless communications present an opportunity to open direct data transmission and feedback between peripheral health workers and central managers. In November 2009, the Uganda Ministry of Health deployed a short message service–based reporting system in two districts. At a set-up cost of $100/health facility, local technician support of $ 400 per month, and a cost of $0.53/week/clinic, the SMS reporting system was started at more than 140 clinics. Positivity rates for rapid diagnostic tests and artemisinin combination therapy stock outs were 48% and 54% in Kabale and 71% and 54% in Gulu, among other reports, at more than 85% health facilities reporting weekly and without monetary incentives or additional supervision. The SMS-based reporting systems have potential to improve timeliness in reporting of specific, time-sensitive metrics at modest cost, while by-passing current bottlenecks in the flow of data. With the development of specific capacity to manage stock data at district level, the availability of timely data offers potential to address commodity distribution problems and reduce stock-outs.
Variation in Clinical Presentation and Genotype of Causative Leishmania major Strain in Cutaneous Leishmaniasis in North and South Afghanistan
Authors: van Thiel Pieter-Paul A. M. , van Gool Tom , Faber William R. , Leenstra Tjalling , Kager Piet A. , Bart Aldert
Published: July 2011

A different clinical picture and therapeutic response were observed when data from Leishmania major-infected Dutch military personnel stationed in southern (N = 8) and northern (N = 169) Afghanistan were analyzed. Clinical presentation of cutaneous leishmaniasis in personnel in the south was milder and seemed to respond better to antileishmanial treatment; molecular analyses of parasite isolates seem to indicate that these differences may be genetic.
Epidemiologic Trends of Rabies in Domestic Animals in Southern Thailand, 1994–2008
Authors: Thiptara Anyarat , Atwill Edward R. , Kongkaew Wandee , Chomel Bruno B.
Published: July 2011

Rabies and associated risk factors in dogs, cats and cattle (n = 3,454) in southern Thailand during 1994–2008 were evaluated by using a mixed-effect logistic regression model. Overall prevalence was 48%. In dogs, odds of being rabid were 1.7 times higher in unvaccinated dogs than in vaccinated dogs and two times higher in dogs with bite history than in dogs with no known bite history. Similarly, aggressive dogs were more likely to be rabid than non-aggressive dogs. In cattle, aggression, pharyngeal paralysis, hyperactivity, and depression were clinical signs associated with being rabid. Annual fluctuations of the species-specific prevalence of rabies is suggestive of a positive correlation between canine and either feline (r = 0.60, P = 0.05) or bovine rabies (r = 0.78, P = 0.004). Insufficient vaccination coverage led to maintenance of rabies, which could be easily controlled by increased vaccine coverage and public education.
An Integrated Strategy for Transmission Control of Schistosoma japonicum in a Marshland Area of China: Findings from a Five-Year Longitudinal Survey and Mathematical Modeling
Authors: Zhou Yi-Biao , Liang Song , Chen Geng-Xin , Rea Chris , He Zong-Gui , Zhang Zhi-Jie , Wei Jian-Guo , Zhao Gen-Ming , Jiang Qing-Wu
Published: July 2011

In 2004 an aggressive plan was instituted aiming to achieve nationwide transmission control of schistosomiasis by 2015. Here, we report a longitudinal study on the control of schistosomiasis in Anhui province, China. Using a mathematical model, we compared the effects of different control strategies implemented in the study area. During the 5-year study period, a 60.8% reduction in human prevalence was observed from 2005 (7.95%) to 2009 (3.1%), and snail infection decreased from 0.063% in 2005 to zero in 2009. Results of the model agree well with the first 3-year field observations and suggest continuous decrease in human infections in the last 2 years, whereas the last 2-year field observations indicated that human infections appeared to be stable even with continuous control. Our findings showed that the integrated control strategy was effective, and we speculated that other factors besides bovines might contribute to the local transmission of the disease.
Increasing Incidence of Ehrlichia chaffeensis and Anaplasma phagocytophilum in the United States, 2000–2007
Authors: Dahlgren F. Scott , Mandel Eric J. , Krebs John W. , Massung Robert F. , McQuiston Jennifer H.
Published: July 2011

Ehrlichia chaffeensis causes human monocytic ehrlichiosis, and Anaplasma phagocytophilum causes human granulocytic anaplasmosis. These related tick-borne rickettsial organisms can cause severe and fatal illness. During 2000–2007, the reported incidence rate of E. chaffeensis increased from 0.80 to 3.0 cases/million persons/year. The case-fatality rate was 1.9%, and the hospitalization rate was 49%. During 2000–2007, the reported incidence of A. phagocytophilum increased from 1.4 to 3.0 cases/million persons/year. The case-fatality rate was 0.6%, and the hospitalization rate was 36%. Rates among female patients were lower than among male patients for ehrlichiosis (rate ratio = 0.68) and anaplasmosis (rate ratio = 0.70). Most (80%) ehrlichiosis and anaplasmosis cases met only a probable case definition, although, use of a polymerase chain reaction to confirm infections increased during 2000–2007. Heightened reporting of these diseases will likely continue with improving recognition, changing surveillance practices, and appropriate application of diagnostic assays.
Etiology of Suspected Pneumonia in Adults Admitted to a High-Dependency Unit in Blantyre, Malawi
Authors: Hartung Thomas K. , Chimbayo Daniel , van Oosterhout Joep J. G. , Chikaonda Tarsizio , van Doornum Gerard J. J. , Claas Eric C. J. , Melchers Willem J. G. , Molyneux Malcolm E. , Zijlstra Ed E.
Published: July 2011

The microbiologic etiology of severe pneumonia in hospitalized patients is rarely known in sub-Saharan Africa. Through a comprehensive diagnostic work-up, we aimed to identify the causative agent in severely ill patients with a clinical picture of pneumonia admitted to a high-dependency unit. A final diagnosis was made and categorized as confirmed or probable by using predefined criteria. Fifty-one patients were recruited (45% females), with a mean age of 35 years (range = 17–88 years), of whom 11(22%) died. Forty-eight (94%) of the patients were seropositive for human immunodeficiency virus; 14 (29%) of these patients were receiving antiretroviral treatment. Final diagnoses were bacterial pneumonia (29%), Pneumocystis jirovecii pneumonia (27%), pulmonary tuberculosis (22%), and pulmonary Kaposi's sarcoma (16%); 39 (77%) of these cases were confirmed cases. Fifteen (29%) patients had multiple isolates. At least 3 of 11 viral-positive polymerase chain reaction (PCR) results of bronchoalveolar lavage fluid were attributed clinical relevance. No atypical bacterial organisms were found.
A Patient Presenting with Diffuse Cutaneous Leishmaniasis (DCL) as a First Indicator of HIV Infection in India
Authors: Khandelwal Kanika , Bumb Ram Awatar , Mehta Rajesh Dutt , Kaushal Himanshu , Lezama-Davila Claudio , Salotra Poonam , Satoskar Abhay R.
Published: July 2011

Opportunistic parasitic infections such as leishmaniasis are common in human immunodeficiency virus (HIV)-infected patients and are usually acquired several days after initial diagnosis of HIV infection. Here, we report on a patient who presented with diffuse cutaneous leishmaniasis (DCL) caused by Leishmania tropica as the first and only clinical manifestation of HIV infection. To the best of our knowledge, this is the first case that illustrates that DCL could be the first clinical indicator of HIV infection. Cutaneous leishmaniasis (CL) and DCL are becoming frequent opportunistic infections in HIV-infected individuals throughout the world. To date, all documented cases of CL and HIV coinfections have been reported in patients who were known cases of HIV and who subsequently developed CL. In this report, we present a case that illustrates that DCL could be the first clinical indicator of HIV infection.
Phase IV Trial of Miltefosine in Adults and Children for Treatment of Visceral Leishmaniasis (Kala-Azar) in Bangladesh
Authors: Rahman Mahmudur , Ahmed Be-Nazir , Faiz M. Abul , Chowdhury M. Zafor Ullah , Islam Quazi Tarikul , Sayeedur Rahman , Rahman M. Ridwanur , Hossain Moazzem , Bangali Abdul Mannan , Ahmad Ziauddin , Islam M. Nazrul , Mascie-Taylor C. G. Nicholas , Berman Jonathan , Arana Byron
Published: July 2011

Miltefosine (target dose of 2.5 mg/kg/day for 28 days) is the recommended treatment for visceral leishmaniasis (kala-azar) in Bangladesh on the basis of data from India. We evaluated miltefosine in a phase IV trial of 977 patients in Bangladesh. At the six-month final follow up, 701 were cured. 24 showed initial treatment failure, and 95 showed treatment failure at 6 months, although 73 of the 95 showed treatment failure solely by the criterion of low hemoglobin values. One hundred twenty-one patients were not assessable. With the conservative assumption that all low hemoglobin values represented treatment failure, the final per protocol cure rate was 85%. Of 13 severe adverse events, 6 led to treatment discontinuation and 7 resulted in deaths, but only 1 death (associated with diarrhea) could be attributed to drug. Nearly all non-serious adverse events were gastrointestinal: vomiting in 25% of patients and diarrhea in 8% of patients. Oral miltefosine is an attractive alternative to intramuscular antimony and intravenous amphotericin B for treatment of kala-azar in Bangladesh.
West Nile and Usutu Viruses in Mosquitoes in Spain, 2008–2009
Authors: Vázquez Ana , Ruiz Santiago , Herrero Laura , Moreno Juana , Molero Francisca , Magallanes Antonio , Sánchez-Seco Maria Paz , Figuerola Jordi , Tenorio Antonio
Published: July 2011

West Nile virus lineage 1 (similar to the strains obtained from golden eagles in Spain, 2007) and Usutu virus (similar to the strains obtained from Culex pipiens in Spain, 2006) were detected in pools from Culex perexiguus collected in southern Spain in 2008 and 2009, respectively. This is the first detection and isolation of West Nile virus lineage 1 from mosquitoes in Spain.
Antibody Responses to the Immunodominant Cryptosporidium gp15 Antigen and gp15 Polymorphisms in a Case–Control Study of Cryptosporidiosis in Children in Bangladesh
Authors: Allison Genève M. , Rogers Kathleen A. , Borad Anoli , Ahmed Sabeena , Karim Mohammad Mahbubul , Kane Anne V. , Hibberd Patricia L. , Naumova Elena N. , Calderwood Stephen B. , Ryan Edward T. , Khan Wasif A. , Ward Honorine D.
Published: July 2011

Although Cryptospridium hominis is the dominant Cryptosporidium species infecting humans, immune responses to cognate antigens in C. hominis-infected persons have not been reported. We investigated antibody responses to the immunodominant gp15 antigen from C. hominis and C. parvum, in C. hominis-infected Bangladeshi children less than five years of age with diarrhea (cases) and uninfected children with diarrhea (controls). We also investigated polymorphisms in the C. hominis gp15 sequence from cases. Serum IgG responses to gp15 from both species were significantly greater in cases than controls. In spite of polymorphisms in the gp15 sequence, there was a significant correlation between antibody levels to gp15 from both species, indicating cross-reactivity to conserved epitopes. Cases with acute diarrhea had a significantly greater serum IgA response to gp15 compared with those with persistent diarrhea, suggesting that this response may be associated with protection from prolonged disease. These findings support further investigation of gp15 as a vaccine candidate.
Incidence of Bacteremic Melioidosis in Eastern and Northeastern Thailand
Authors: Bhengsri Saithip , Baggett Henry C. , Jorakate Possawat , Kaewpan Anek , Prapasiri Prabda , Naorat Sathapana , Thamthitiwat Somsak , Tanwisaid Kittisak , Chantra Somrak , Salika Prasert , Dejsirilert Surang , Peruski Leonard F. , Maloney Susan A.
Published: July 2011

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in northeastern Thailand. Population-based disease burden estimates are lacking and limited data on melioidosis exist from other regions of the country. Using active, population-based surveillance, we measured the incidence of bacteremic melioidosis in the provinces of Sa Kaeo (eastern Thailand) and Nakhon Phanom (northeastern Thailand) during 2006–2008. The average annual incidence in Sa Kaeo and Nakhon Phanom per 100,000 persons was 4.9 (95% confidence interval [CI] = 3.9–6.1) and 14.9 (95% CI = 13.3–16.6). The respective population mortality rates were 1.9 (95% CI = 1.3–2.8) and 4.4 (95% CI = 3.6–5.3) per 100,000. The case-fatality proportion was 36% among those with known outcome. Our findings document a high incidence and case fatality proportion of bacteremic melioidosis in Thailand, including a region not traditionally considered highly endemic, and have potential implications for clinical management and health policy.
Vector Competence of New Zealand Mosquitoes for Selected Arboviruses
Authors: Kramer Laura D. , Chin Pam , Cane Rachel P. , Kauffman Elizabeth B. , Mackereth Graham
Published: July 2011

New Zealand (NZ) historically has been free of arboviral activity with the exception of Whataroa virus (Togaviridae: Alphavirus), which is established in bird populations and is transmitted by local mosquitoes. This naive situation is threatened by global warming, invasive mosquitoes, and tourism. To determine the threat of selected medically important arboviruses to NZ, vector competence assays were conducted using field collected endemic and introduced mosquito species. Four alphaviruses (Togaviridae): Barmah Forest virus, Chikungunya virus, Ross River virus, and Sindbis virus, and five flaviviruses (Flaviviridae): Dengue virus 2, Japanese encephalitis virus, Murray Valley encephalitis virus, West Nile virus, and Yellow fever virus were evaluated. Results indicate some NZ mosquito species are highly competent vectors of selected arboviruses, particularly alphaviruses, and may pose a threat were one of these arboviruses introduced at a time when the vector was prevalent and the climatic conditions favorable for virus transmission.
A mirror has no effect on giving in the dictator game
Authors: Niwa Yuki , Hiraishi Kai , Oda Ryo
Published: July 2011

Evolutionary studies on human altruism toward strangers have proposed two motivations as proximate mechanisms for this behavior. The first involves the positive motivations inherent in expecting that actors will benefit in the long term by building a good reputation even if they accrue immediate costs for their altruistic behavior. The second involves the negative motivations inherent in avoiding identification as a norm violator. The presence of a mirror has been reported to enhance self-consciousness and evoke negative affect in response to an observer’s eyes. We conducted the dictator game with and without a mirror. Participants were asked to complete a post-experiment questionnaire designed to investigate what they were thinking when they decided the amount of money to offer the recipient and to explore their perceptions of the experimental situation. Although the negative affect elicited by an observer’s eyes was stronger under the mirror condition, the presence of the mirror did not increase the amount of money offered in the game.
Organic functional groups in aerosol particles from burning and non-burning forest emissions at a high-elevation mountain site
Authors: Takahama S. , Schwartz R. E. , Russell L. M. , Macdonald A. M. , Sharma S. , Leaitch W. R.
Published: July 2011

Abstract. Ambient particles collected on teflon filters at the Peak of Whistler Mountain, British Columbia (2182 m a.s.l.) during spring and summer 2009 were measured by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFG). The project mean and standard deviation of organic aerosol mass concentrations (OM) for all samples was 3.2±3.3 (μg m−3). Measurements of aerosol mass fragments, size, and number concentrations were used to separate fossil-fuel combustion and burning and non-burning forest sources of the measured organic aerosol. The OM was composed of the same anthropogenic and non-burning forest components observed at Whistler mid-valley in the spring of 2008; during the 2009 campaign, biomass burning aerosol was additionally observed from fire episodes occurring between June and September. On average, organic hydroxyl, alkane, carboxylic acid, ketone, and primary amine groups represented 31 %±11 %, 34 %±9 %, 23 %±6 %, 6 %±7 %, and 6 %±3 % of OM, respectively. Ketones in aerosols were associated with burning and non-burning forest origins, and represented up to 27 % of the OM. The organic aerosol fraction resided almost entirely in the submicron fraction without significant diurnal variations. OM/OC mass ratios ranged mostly between 2.0 and 2.2 and O/C atomic ratios between 0.57 and 0.76, indicating that the organic aerosol reaching the site was highly aged and possibly formed through secondary formation processes.
Airborne observations of mineral dust over western Africa in the summer Monsoon season: spatial and vertical variability of physico-chemical and optical properties
Authors: Formenti P. , Rajot J. L. , Desboeufs K. , Saïd F. , Grand N. , Chevaillier S. , Schmechtig C.
Published: July 2011

Abstract. We performed airborne measurements of aerosol particle concentration, composition, size distribution and optical properties over Western Africa in the corridor 2–17° N and 3–5° E. Data were collected on board the French ATR-42 research aircraft in June–July 2006 as part of the African Monsoon Multidisciplinary Analysis (AMMA) intensive field phases in June–July 2006 using the AVIRAD airborne aerosol sampling system. The aerosol vertical distribution was documented on an almost daily basis. In particular, the vertical distribution of mineral dust emitted locally by Mesoscale Convective Systems (MSC) was distinguished from that of mineral dust that was transported from the Saharan by the African Easterly Jet (AEJ). Mineral dust emitted in the Sahel by convection-driven erosion was mostly confined in the boundary layer. One episode of injection of Sahelian mineral dust in the AEJ was observed. The elemental composition was found to be an element of difference between episodes, whereas the volume size distribution was more uniform. For non-mixed dust, the single scattering albedo ranged between 0.88–0.93 at 370 nm and between 0.91–0.99 at 950 nm, lower values being observed for Sahelian dust. In correspondence, the imaginary part of the complex refractive index varied between 0.002–0.004 at 370 nm and between 0.001–0.002 at 950 nm.
Effect of relative humidity on SOA formation from isoprene/NO photooxidation: enhancement of 2-methylglyceric acid and its corresponding oligoesters under dry conditions
Authors: Zhang H. , Surratt J. D. , Lin Y. H. , Bapat J. , Kamens R. M.
Published: July 2011

Abstract. The effect of relative humidity (RH) on secondary organic aerosol (SOA) formation from the photooxidation of isoprene under initially high nitric oxide (NO) conditions (i.e., isoprene/NO ~3) was investigated in a dual outdoor smog chamber. Based upon particle volume concentration measurements and the detailed chemical characterization of isoprene SOA using gas chromatography/mass spectrometry (GC/MS) and ultra performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), enhanced SOA formation was observed under lower RH conditions (15–40 %) compared to higher RH conditions (40–90 %). 2-methylglyceric acid (2-MG) and its corresponding oligoesters, which have been previously shown to form from further oxidation of methacryloylperoxynitrate (MPAN), were enhanced in the particle-phase under lower RH conditions. In addition, an abundant unknown SOA tracer likely derived from the further oxidation of MPAN was detected and enhanced under lower RH conditions. In contrast, the 2-methyltetrols, which are known to mainly form from the reactive uptake of isoprene epoxydiols (IEPOX) under low-NO conditions in the presence of acidified aerosol, did not substantially vary under different RH conditions; however, isoprene-derived organosulfates were found to be enhanced under high-RH conditions, indicating the likely importance of the aqueous aerosol phase in their formation. Based upon the detailed chemical characterization results, particle-phase organic esterification is tentatively proposed to explain the observed enhancements of isoprene SOA mass under lower RH conditions. Alternative mechanisms explaining the enhancement of 2-MG and its corresponding oligoesters cannot be completely ruled out. This is one of only a few chamber studies that have examined the effect of RH on isoprene SOA formation. In comparison to our recent results obtained from aromatic SOA formation, the effect of RH on isoprene SOA formation is reversed. The results of this study highlight the importance of elucidating the key reactive intermediates that lead to SOA formation, especially since RH likely affects their ability in forming SOA. Furthermore, ignoring the effects of RH may significantly affect the accuracy of both regional and global SOA models.
H2 vertical profiles in the continental boundary layer: measurements at the Cabauw tall tower in The Netherlands
Authors: Popa M. E. , Vermeulen A. T. , van den Bulk W. C. M. , Jongejan P. A. C. , Batenburg A. M. , Zahorowski W. , Röckmann T.
Published: July 2011

Abstract. In-situ, quasi-continuous measurements of atmospheric hydrogen (H2) have been performed since October 2007 at the Cabauw tall tower station in the Netherlands. Mole fractions of H2, CO and several greenhouse gases are determined simultaneously in air sampled successively at four heights, between 20 and 200 m above ground level. 222Rn measurements are performed in air sampled at 20 and 200 m. This H2 dataset represents the first in-situ, quasi-continuous long-term measurement series of vertical profiles of H2 in the lower continental boundary layer. Seasonal cycles are present at all heights in both H2 and CO, and their amplitude varies with the sampling height. The seasonality is evident in both the "baseline" values and in the short term (diurnal to synoptic time scales) variability, the latter being significantly larger during winter. The observed H2 short term signals and vertical gradients are in many cases well correlated to other species, especially to CO. On the other hand, H2 has at times a unique behaviour, due to its particular distribution of sources and sinks. Our estimation for the regional H2 soil uptake flux, using the radon tracer method, is (−1.89 ± 0.26) × 10−5 g/(m2 h), significantly smaller than other recent results from Europe. H2/CO ratios of the traffic emissions computed from our data, with an average of 0.54 ± 0.07 mol:mol, are larger and more variable than estimated in some of the previous studies in Europe. This difference can be explained by a different driving regime, due to the frequent traffic jams in the influence area of Cabauw. The H2/CO ratios of the large scale pollution events have an average of 0.36 ± 0.05 mol:mol; these ratios were observed to slightly increase with sampling height, possibly due to a stronger influence of soil uptake at the lower sampling heights.
TransCom continuous experiment: comparison of 222Rn transport at hourly time scales at three stations in Germany
Authors: Taguchi S. , Law R. M. , Rödenbeck C. , Patra P. K. , Maksyutov S. , Zahorowski W. , Sartorius H. , Levin I.
Published: July 2011

Abstract. Fourteen global atmospheric transport models were evaluated by comparing the simulation of 222Rn against measurements at three continental stations in Germany: Heidelberg, Freiburg and Schauinsland. Hourly concentrations simulated using a common 222Rn-flux without temporal variations were investigated for 2002 and 2003. We found that the mean simulated concentrations in Heidelberg are related to the diurnal amplitude of boundary layer height in each model. Summer mean concentrations simulated by individual models were negatively correlated with the seasonal mean of diurnal amplitude of boundary layer height, while in winter the correlation was positive. We also found that the correlations between simulated and measured concentrations at Schauinsland were higher when the simulated concentrations were interpolated to the station altitude in most models. Temporal variations of the mismatch between simulated and measured concentrations suggest that there are significant interannual variations in the 222Rn exhalation rate in this region. We find that the local inversion layer during daytime in summer in Freiburg has a significant effect on 222Rn concentrations. We recommend Freiburg concentrations for validation of models that resolve local stable layers and those at Heidelberg for models without this capability.
Observing requirements for geostationary satellites to enable ozone air quality prediction
Authors: Hamer P. D. , Bowman K. W. , Henze D. K.
Published: July 2011

Abstract. We conduct a variety of analyses to support mission planning for geostationary satellite measurements of atmospheric composition. We carry out a simplified observing system simulation experiment (OSSE) using a photochemical box model and its adjoint integrated with a Lagrangian 4-D-variational data assimilation system. Using this framework in conjunction with pseudo observational constraints we estimate surface emissions and assess the improvement in ozone air quality forecasting and prediction. We use an analytical model as our principle method of conducting uncertainty analyses, which is the primary focus of this work. We investigate the impacts of changing the observed species (e.g., ozone, carbon monoxide (CO), nitrogen dioxide (NO2), and formaldehyde (HCHO)), observation frequency and quality upon the ability to predict the magnitude of summertime peak ozone events, characterize the uncertainties of those predictions, and the performance of the assimilation system. We use three observed species scenarios: CO and NO2; ozone, CO, and NO2; and HCHO, CO and NO2. These scenarios are designed to test the effects of adding observations of either ozone or HCHO to an existing CO and NO2 observing system. The studies were conducted using the photochemical model setup to simulate a range of summertime polluted environments spanning NOx limited to volatile organic compound (VOC) limited conditions. As the photochemical regime changes the relative importance of trace gas observations to constrain emission estimates and subsequent ozone forecasts varies. For example, adding ozone observations to an NO2 and CO observing system is found to decrease ozone prediction error under NOx and VOC limited regimes, and complimenting the NO2 and CO system with HCHO observations would improve ozone prediction in the transitional regime and under VOC limited conditions.
Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter–spring: implications for radiative forcing
Authors: Wang Q. , Jacob D. J. , Fisher J. A. , Mao J. , Leibensperger E. M. , Carouge C. C. , Le Sager P. , Kondo Y. , Jimenez J. L. , Cubison M. J. , Doherty S. J.
Published: July 2011

Abstract. We use a global chemical transport model (GEOS-Chem CTM) to interpret observations of black carbon (BC) and organic aerosol (OA) from the NASA ARCTAS aircraft campaign over the North American Arctic in April 2008, together with longer-term records in surface air and in snow. We find that Russian open fires were the dominant source of OA in the troposphere during ARCTAS but that BC was more of anthropogenic origin, particularly in surface air. This source attribution is confirmed by correlation of BC and OA with acetonitrile and sulfate in the model and in the observations. Asian emissions are the main anthropogenic source of BC in the free troposphere but European, Russian and North American sources are also important in surface air. Russian anthropogenic emissions appear to dominate the Arctic source of BC in surface air in winter. Open fire influences on Arctic surface BC in spring are much higher in the Eurasian than in the North American sector. Most of the BC transported to the Arctic in the lower troposphere is deposited within the Arctic, in contrast to the BC transported at higher altitudes. Pan-Arctic 2007–2009 observations of BC concentrations in snow are well reproduced by the model, with maximum values in the Russian Arctic and much lower values in the North American Arctic. We find that anthropogenic sources contribute 90% of BC deposited to Arctic snow in January–March and 57% in April–May 2007–2009. The mean decrease in Arctic snow albedo from BC deposition is estimated to be 0.6% in spring 2007–2009, resulting in a regional surface radiative forcing consistent with previous estimates.
Observation of strato-mesospheric CO above Kiruna with ground-based microwave radiometry – retrieval and satellite comparison
Authors: Hoffmann C. G. , Raffalski U. , Palm M. , Funke B. , Golchert S. H. W. , Hochschild G. , Notholt J.
Published: July 2011

Abstract. CO serves as a tracer for dynamics in the polar winter middle atmosphere. This work presents the retrieval and the characterization of ground-based CO measurements from the winters 2008/2009 and 2009/2010 by the Kiruna microwave radiometer KIMRA, located in northern Sweden (67.8° N, 20.4° E). Furthermore, the dataset is used for an extensive comparison to the recent satellite instruments MLS on Aura, ACE-FTS, and MIPAS on Envisat. The vmr profiles are retrieved using the Optimal Estimation approach. A detailed analysis of the averaging kernel functions is carried out, showing sensitivity of the measurements between 40 and 80 km altitude, a vertical resolution of 16 to 22 km, as well as a residual influence of the region up to 130 km altitude. An error assessment reveals a total error of the retrieved profile that increases with altitude and is approx. ±0.1 ppmv at 50 km altitude and ±3 ppmv at 80 km altitude. The main contributions to this total error arise from the measurement noise and the uncertainty of the used temperature profiles. The expected dynamical features of the polar winter middle atmosphere are qualitatively identified in the retrieved time series, but are not quantitatively analyzed here. The dense MLS dataset is used to investigate the influence of the collocation criteria on the satellite comparison, showing that relaxing the distance criterion causes a high bias for MLS. The comparison including the other instruments is difficult because of the small number of coincidences. However, it suggests that there is a general agreement between KIMRA and the satellite instruments below 65 km altitude, but a high bias for KIMRA above this altitude. Furthermore, the shape of the KIMRA profile appears to be systematically different from the satellite profiles.
Glacial-interglacial vegetation dynamics in south eastern Africa depend on sea surface temperature variations in the west Indian Ocean
Authors: Dupont L. M. , Caley T. , Kim J.-H. , Castaneda I. , Malaizé B. , Giraudeau J.
Published: July 2011

Abstract. Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between Indian and Atlantic Ocean. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ~120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (down till 342 ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including elements with affinity to the Cape Flora) for the last glacial as well as for other glacial periods of the past 300 ka.
Evaluation of ice and snow content in the global numerical weather prediction model GME with CloudSat
Authors: Reitter S. , Fröhlich K. , Seifert A. , Crewell S. , Mech M.
Published: July 2011

Abstract. The present study evaluates the global numerical weather prediction model GME with respect to the grid-scale parameterization of frozen particles, both ice and snow, focusing on the performance of a diagnostic versus a prognostic precipitation scheme. As a reference, CloudSat Cloud Profiling Radar observations are utilized – the so far only near-globally available data set which vertically resolves clouds. Both the observation-to-model and the model-to-observation approach are applied and compared to each other. For the latter, the radar simulator QuickBeam is utilized. Criteria are applied to further improve the comparability between model and observations. The two model versions are statistically evaluated for a four-month period. The comparison reveals that the prognostic scheme reproduces the shape of the CloudSat frequency distributions for both ice water content (IWC) and reflectivity factor well, while the diagnostic scheme produces no large IWCs or reflectivity factors because snow falls out instantaneously. However, the prognostic scheme overestimates the occurrence of high ice water paths (IWP), especially in the mid-latitudes. Sensitivity tests show that an increased fall speed of snow successfully reduces IWP. Both evaluation approaches capture the general features, but for details, the two together deliver the largest informational content. In case of limited resources, the model-to-observation approach is recommended. Finally, the results indicate that the lack of IWC in most global circulation models might be attributed to the use of diagnostic precipitation schemes, i.e., the lack of snow aloft. Based on its good performance the prognostic scheme went into operational mode in February 2010. The adjusted snow fall speed went operational in December 2010. However, continual improvements of the ice microphysics are necessary, which can be assessed by the proposed evaluation technique.
Regional-scale identification of groundwater-surface water interaction using hydrochemistry and multivariate statistical methods, Wairarapa Valley, New Zealand
Authors: Guggenmos M. R. , Daughney C. J. , Jackson B. M. , Morgenstern U.
Published: July 2011

Abstract. Identifying areas of interaction between groundwater and surface water is crucial for effective environmental management, because this interaction is known to influence water quantity and quality. This paper applies hydrochemistry and multivariate statistics to identify locations and mechanisms of groundwater-surface water interaction in the pastorally dominated Wairarapa Valley, New Zealand. Hierarchical Cluster Analysis (HCA) and Principal Components Analysis (PCA) were conducted using site-specific median values of Ca, Mg, Na, K, HCO3, Cl, SO4 and electrical conductivity from 22 surface water sites and 246 groundwater sites. Surface water and groundwater monitoring sites were grouped together in three of the seven clusters identified by HCA, with the inference made that similarities in hydrochemistry indicate groundwater-surface water interaction. PCA indicated that the clusters were largely differentiated by total dissolved solids concentration, redox potential and ratio of major ions. Shallow aerobic groundwaters, located in close proximity to losing reaches of rivers, were grouped with similar Ca-HCO3 type surface waters, indicating potential recharge to aquifers from these river systems. Groundwaters that displayed a rainfall-recharged chemical signature with higher Na relative to Ca, higher Cl relative to HCO3 and an accumulation of NO3 were grouped with neighbouring surface waters, suggesting the provision of groundwater base flow to these river systems and the transfer of this chemical signature from underlying aquifers. The hydrochemical techniques used in this study did not reveal groundwater-surface water interaction in some parts of the study area, specifically where deep anoxic groundwaters, high in total dissolved solids with a distinct Na-Cl signature, showed no apparent link to surface water. The drivers of hydrochemistry inferred from HCA and PCA are consistent with previous measurements of 18O, water age and excess air. Overall, this study has shown that multivariate statistics can be used as a rapid method to identify groundwater-surface water interaction at a regional scale using existing hydrochemical datasets.
Dynamic versus static neural network model for rainfall forecasting at Klang River Basin, Malaysia
Authors: El-Shafie A. , Noureldin A. , Taha M. R. , Hussain A.
Published: July 2011

Abstract. Rainfall is considered as one of the major component of the hydrological process, it takes significant part of evaluating drought and flooding events. Therefore, it is important to have accurate model for rainfall forecasting. Recently, several data-driven modeling approaches have been investigated to perform such forecasting task such as Multi-Layer Perceptron Neural Networks (MLP-NN). In fact, the rainfall time series modeling involves an important temporal dimension. On the other hand, the classical MLP-NN is a static and memoryless network architecture that is effective for complex nonlinear static mapping. This research focuses on investigating the potential of introducing a neural network that could address the temporal relationships of the rainfall series. Two different static neural networks and one dynamic neural network namely; Multi-Layer Peceptron Neural network (MLP-NN), Radial Basis Function Neural Network (RBFNN) and Input Delay Neural Network (IDNN), respectively, have been examined in this study. Those models had been developed for two time horizon in monthly and weekly rainfall basis forecasting at Klang River, Malaysia. Data collected over 12 yr (1997–2008) on weekly basis and 22 yr (1987–2008) for monthly basis were used to develop and examine the performance of the proposed models. Comprehensive comparison analyses were carried out to evaluate the performance of the proposed static and dynamic neural network. Results showed that MLP-NN neural network model able to follow the similar trend of the actual rainfall, yet it still relatively poor. RBFNN model achieved better accuracy over the MLP-NN model. Moreover, the forecasting accuracy of the IDNN model outperformed during training and testing stage which prove a consistent level of accuracy with seen and unseen data. Furthermore, the IDNN significantly enhance the forecasting accuracy if compared with the other static neural network model as they could memorize the sequential or time varying patterns.
Effects of peatland drainage management on peak flows
Authors: Ballard C. E. , McIntyre N. , Wheater H. S.
Published: July 2011

Abstract. Open ditch drainage has historically been a common land management practice in upland blanket peats, particularly in the UK. However, peatland drainage is now generally considered to have adverse effects on the upland environment, including increased peak flows. As a result, drain blocking has become a common management strategy in the UK over recent years, although there is only anecdotal evidence to suggest that this might decrease peak flows. The change in the hydrological regime associated with the drainage of blanket peat and the subsequent blocking of drains is poorly understood, therefore a new physics-based model has been developed that allows the exploration of the associated hydrological processes. A series of simulations is used to explore the response of intact, drained and blocked drain sites at field scales. While drainage is generally found to increase peak flows, the effect of drain blocking appears to be dependent on local conditions, sometimes decreasing and sometimes increasing peak flows. Based on insights from these simulations we propose guidelines for identifying those drains that would most greatly reduce peak flows if blocked.
Soil-gas radon monitoring in an active granite quarry from central Portugal
Authors: Pereira A. J. S. C. , Barbosa S. M. , Neves L. J. P. F. , Aumento F.
Published: July 2011

Abstract. Seven soil-gas radon monitoring stations were placed along the active front of a granite quarry in Canas de senhorim, Central Portugal, recording continuously for 81 days. Important differences in the radon concentration were found between stations, with average values comprised between 102 and 2982 Bq m−3, which can be explained by the local presence of uranium anomalies in the regional late-orogenic Hercynian granite, usually associated with faults. One of the boreholes exhibits large radon anomalies lasting for several days, and two, contrary to the others, show a clear daily periodic behaviour, with minima around 19:00 LT and maxima around 07:00 LT. The different patterns observed in stations placed at such a short distance (<100 m) has no clear explanation and deserves further investigation. Data analysis shows no evidence of soil-gas radon concentration changes during explosions carried out at the quarry. This is likely to result from the absence of a progressive stress field affecting the rock, as typically occurs before an earthquake.