bluuebunny/crossref_metadata_2025 huggingface dataset:
Flowering and biomass allocation in U.S. Atlantic coast Spartina alterniflora
Authors: Crosby Sarah C. , Ivens‐Duran Morgan , Bertness Mark D. , Davey Earl , Deegan Linda A. , Leslie Heather M.
Published: May 2015

• Premise of the study: Salt marshes are highly productive and valuable ecosystems, providing many services on which people depend. Spartina alterniflora Loisel (Poaceae) is a foundation species that builds and maintains salt marshes. Despite this species' importance, much of its basic reproductive biology is not well understood, including flowering phenology, seed production, and the effects of flowering on growth and biomass allocation. We sought to better understand these life history traits and use that knowledge to consider how this species may be affected by climate change.

• Methods: We examined temporal and spatial patterns in flowering and seed production in S. alterniflora at a latitudinal scale (along the U.S. Atlantic coast), regional scale (within New England), and local scale (among subhabitats within marshes) and determined the impact of flowering on growth allocation using field and greenhouse studies.

• Key results: Flowering stem density did not vary along a latitudinal gradient, while at the local scale plants in the less submerged panne subhabitats produced fewer flowers and seeds than those in more frequently submerged subhabitats. We also found that a shift in biomass allocation from above to belowground was temporally related to flowering phenology.

• Conclusions: We expect that environmental change will affect seed production and that the phenological relationship with flowering will result in limitations to belowground production and thus affect marsh elevation gain. Salt marshes provide an excellent model system for exploring the interactions between plant ecology and ecosystem functioning, enabling better predictions of climate change impacts.
Genetic analysis of rhizomatousness and its relationship with vegetative branching of recombinant inbred lines of Sorghum bicolor × S. propinquum
Authors: Kong Wenqian , Kim Changsoo , Goff Valorie H. , Zhang Dong , Paterson Andrew H.
Published: May 2015

• Premise of the study: Rhizomes, subterranean stems that grow horizontally, are a storage organ that is highly associated with overwintering and regrowth. This quantitative study aimed to discover genetic determinants of rhizomatousness, an important trait related to perenniality and invasiveness.

• Methods: A population of 161 individuals of a recombinant inbred line (RIL) derived from morphologically distinct parents, Sorghum bicolor and Sorghum propinquum, which segregates for rhizomatousness, was phenotyped and genetically mapped.

• Key results: Seven genomic regions influenced rhizomatousness in this population; four were “consensus” regions that correspond with previously detected quantitative trait loci (QTLs) in an F2 population of the same pedigree and with different levels of vegetative branching. Because rhizomatousness is a plastic trait that is greatly influenced by environment, overlap between regions discovered in the RIL and F2 populations validates the position and effect of QTLs. Correspondence with regions influencing vegetative branching indicates that some genes and biochemical pathways may influence both vegetative branching and rhizomatousness, while genes influencing only one trait may confer divergent aspects of development of these organs.

• Conclusions: Identifying genes conferring rhizomatousness and understanding their functions may provide opportunities to regulate plant growth for diverse applications. Increasing rhizomatousness may promote the productivity and perenniality of many grasses, especially biomass‐dedicated crops, while decreasing rhizomatousness may improve monocarpic grain production and offer means to control many noxious weeds.
The convenient preparation of stable aryl-coated zerovalent iron nanoparticles
Authors: Guselnikova Olga A , Galanov Andrey I , Gutakovskii Anton K , Postnikov Pavel S
Published: May 2015

A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs) based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs) were prepared by simple chemical reduction of iron(III) chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material.
Nonpolio Enterovirus Infections in Neonates
Authors: Haston Julia C. , Dixon Terry C.
Published: May 2015

There are currently 12 species and over 100 serotypes that have been identified in the enterovirus genus, including the coxsackieviruses, echoviruses, and polioviruses. Since their discovery 65 years ago, much has been discovered and continues to be researched regarding the pathogenicity and scope of disease of nonpolio enteroviruses. Like many infections, enteroviruses have been found to affect neonates much differently, and often more severely, than older children and adults. Neonatal infections often cause mild illnesses with nonspecific symptoms, but they may also have severe presentations involving the cardiovascular, gastrointestinal, hematologic, or central nervous systems. This article provides an overview of what is known about nonpolio enteroviruses in neonates including epidemiology, transmission, clinical presentation, diagnosis, and treatment.

[
Pediatr Ann
. 2015;44(5):e103–e107.]
Water Treatment, Preventive Measures and the Chronic Kidney Disease in the Farming Community in Sri Lanka
Authors: Ranasinghe H R A L N , Lokuge L D M N , Edirisinghe J C , Bandara L
Published: May 2015

Whilst being accountable for an increasing trend in mortality and morbidity, Chronic Kidney Dis¬ease of unknown aetiology (CKDu) has become a severe burden in Sri Lanka. Even though there is no sound evidence to clarify the aetiology of CKDu, it will be worthwhile to seek out the possible measures to minimize the prevalence of the disease. Hence, this study was intended to examine the impact of water treatment and preventive measures on CKDu. Data were collected from the farm¬ing community who applies agrochemicals. Both a probit and a Logit regression were carried out to check whether there is any relationship between CKDu and related variables such as consump¬tion of treated water and adopting safety precautions. Results reveal that age, being a male, using deep wells as a source of drinking water, and long term medication increases the probability of getting the disease while, both preventive measures and water treatment significantly reduce this probability. Therefore, ensuring an adequate supply of treated water, especially for the severely affected villages is vital. Furthermore, both government and non-government institutions should work responsibly to increase the awareness of CKDu and safety precautions, in order to save the future generation.The Journal of Agricultural Sciences, vol.10, No 2, May 2015, pp. 98-108
Eosinophils Contribute to Early Clearance of Pneumocystis murina Infection
Authors: Eddens Taylor , Elsegeiny Waleed , Nelson Michael P. , Horne William , Campfield Brian T. , Steele Chad , Kolls Jay K.
Published: May 2015

Pneumocystis pneumonia remains a common opportunistic infection in the diverse immunosuppressed population. One clear risk factor for susceptibility to Pneumocystis is a declining CD4+ T cell count in the setting of HIV/AIDS or primary immunodeficiency. Non–HIV-infected individuals taking immunosuppressive drug regimens targeting T cell activation are also susceptible. Given the crucial role of CD4+ T cells in host defense against Pneumocystis, we used RNA sequencing of whole lung early in infection in wild-type and CD4-depleted animals as an unbiased approach to examine mechanisms of fungal clearance. In wild-type mice, a strong eosinophil signature was observed at day 14 post Pneumocystis challenge, and eosinophils were increased in the bronchoalveolar lavage fluid of wild-type mice. Furthermore, eosinophilopoiesis-deficient Gata1tm6Sho/J mice were more susceptible to Pneumocystis infection when compared with BALB/c controls, and bone marrow–derived eosinophils had in vitro Pneumocystis killing activity. To drive eosinophilia in vivo, Rag1−/− mice were treated with a plasmid expressing IL-5 (pIL5) or an empty plasmid control via hydrodynamic injection. The pIL5-treated mice had increased serum IL-5 and eosinophilia in the lung, as well as reduced Pneumocystis burden, compared with mice treated with control plasmid. In addition, pIL5 treatment could induce eosinophilia and reduce Pneumocystis burden in CD4-depleted C57BL/6 and BALB/c mice, but not eosinophilopoiesis-deficient Gata1tm6Sho/J mice. Taken together, these results demonstrate that an early role of CD4+ T cells is to recruit eosinophils to the lung and that eosinophils are a novel candidate for future therapeutic development in the treatment of Pneumocystis pneumonia in the immunosuppressed population.
Bipartite Nuclear Localization Signal Controls Nuclear Import and DNA-Binding Activity of IFN Regulatory Factor 3
Authors: Zhu Mingzhu , Fang Ting , Li Shun , Meng Kun , Guo Deyin
Published: May 2015

Accurate cellular localization plays a crucial role in the effective function of most signaling proteins, and nuclear trafficking is central to the function of transcription factors. IFN regulatory factor (IRF)3 is a master transcription factor responsible for the induction of type I IFN, which plays a crucial role in host antiviral innate immune responses. However, the mechanisms for control and regulation of IRF3 nuclear import largely remain to be elucidated. In our study, we identified a bipartite nuclear localization signal (NLS) in IRF3, with two interdependent basic clusters separated by a 7-aa linker. Our study further demonstrated that the bipartite NLS of IRF3 is also critical for IRF3 DNA-binding activity, indicating that the two functions of this region are integrated, which is in contrast to other IRFs. Furthermore, the IFN bioassay and infection studies suggest that IRF3 NLS is essential to the IRF3-mediated IFN responses and antiviral immunity. Overall, our results reveal a previously unrecognized bipartite NLS for IRF3 that contains both DNA-binding activity and nuclear import function, and they shed light on the regulatory mechanisms of IRF3 activation and IRF3-mediated antiviral responses.
Mapping of the environmental contamination of Toxoplasma gondii by georeferencing isolates from chickens in an endemic area in Southeast Rio de Janeiro State, Brazil
Authors: Casartelli-Alves Luciana , Reis Amendoeira Maria Regina , Cardoso Boechat Viviane , Ferreira Luiz Cláudio , Araujo Carreira João Carlos , Nicolau José Leonardo , De Freitas Trindade Eloiza Paula , De Barros Peixoto Julia Novaes , De Avelar Figueiredo Mafra Magalhães Mônica , De Vasconcellos Carvalhaes de Oliveira Raquel , Pacheco Schubach Tânia Maria , Caldas Menezes Rodrigo
Published: May 2015

The environmental contamination of Toxoplasma gondii in an endemic area in Brazil was mapped by georeferencing isolates from chickens in farms in the Southeast of the state of Rio de Janeiro. Tissue samples obtained from 153 adult chickens were analyzed by the mouse bioassay for T. gondii infection. These animals were reared free-range on 51 farms in the municipalities of Rio Bonito and Maricá. The ArcGIS kernel density estimator based on the frequency of T. gondii-positive chickens was used to map the environmental contamination with this parasite. A questionnaire was applied to obtain data on the presence and management of cats and the type of water consumed. Of the farms studied, 64.7% were found to be located in areas of low to medium presence of T. gondii, 27.5% in areas with a high or very high contamination level and 7.8% in non-contaminated areas. Additionally, 70.6% kept cats, 66.7% were near water sources and 45.0% were in or near dense vegetation. Humans used untreated water for drinking on 41.2% of the farms, while all animals were given untreated water. The intensity of environmental T. gondii contamination was significantly higher on farms situated at a distance >500 m from water sources (P=0.007) and near (≤500 m) dense vegetation (P=0.003). Taken together, the results indicate a high probability of T. gondii infection of humans and animals living on the farms studied. The kernel density estimator obtained based on the frequency of chickens testing positive for T. gondii in the mouse bioassay was useful to map environmental contamination with this parasite.
Spatial abundance and human biting rate of Anopheles arabiensis and Anopheles funestus in savannah and rice agro-ecosystems of Central Tanzania
Authors: Mboera Leonard E.G. , Bwana Veneranda M. , Rumisha Susan F. , Stanley Grades , Tungu Patrick K. , Malima Robert C.
Published: May 2015

This study was carried out to determine the spatial variations in malaria mosquito abundance and human biting rate in five villages representing rice-irrigation and savannah ecosystems in Kilosa District, central Tanzania. The study involved five villages namely Tindiga and Malui (wetland/rice irrigation), Twatwatwa and Mbwade (dry savannah) and Kimamba (wet savannah). Indoor mosquitoes were sampled using Centers for Disease Control and Prevention light traps in three houses in each village. Anopheles gambiae s.l. molecular identification was carried out using polymerase chain reaction (PCR). A total of 936 female mosquitoes were collected. About half (46.9%) were malaria mosquitoes (Anopheles gambiae s.l.=28.6%; An. funestus= 18.3%). A total of 161 (60.1%) of the morphologically identified An. gambiae s.l. (268) and subjected to PCR analysis for speciation were genotyped as An. arabiensis. The An. funestus complex mosquitoes were composed of An. funestus funestus and An. rivulorum at the 5:1 ratio. On average, 17.9 Anopheles mosquitoes were collected per village per day. Two-thirds (62.8%) of the malaria mosquitoes were collected in Malui (rice agro-ecosystem) and the lowest number (2.3%) in Twatwatwa (dry savannah ecosystem). The biting rate per person per night for An. arabiensis+An. funestus s.s. was highest in Malui (46.0) and lowest in Twatwatwa (1.67). The parity rate of the An. funestus mosquitoes was lower compared to that of An. arabiensis and none of the mosquitoes was infected with malaria sporozoites. In conclusion, An. arabiensis is the most abundant malaria vector in Kilosa district and its variation is related to the ecological system. The heterogeneity in malaria mosquito abundance and human biting rate could be used to guide selection of locally appropriated control interventions.
Comparing the perception with the reality of walking in a hilly environment: an accessibility method applied to a University campus in Hong Kong
Authors: Sun Guibo , Haining Robert , Lin Hui , Oreskovic Nicolas M. , He Jie
Published: May 2015

The influence of hilliness on walking behavior could be a consequence of the real effect of the local topography, but individual perception of the difficulties associated with walking in a hilly environment may also be important. Previous studies have found that people’s perceptions do not necessarily match well with the realities of walking in hilly environments. There are a few methods that can be used to visualize the geography of that difference for use by urban planners and public health practitioners. A walking accessibility measure that allows comparison of perception and reality is proposed and implemented in this study. We note that difficulties in calculating accessibility measures in the present context arise primarily from problems with data quality, three-dimensional pedestrian network modelling and the adequacy of accessibility methods for describing and predicting walking behavior. We present practical strategies for addressing these issues using geographic information systems. Our method is illustrated by calculating accessibility for a hilly university campus in Hong Kong. Walking behaviors on, and people’s perceptions of, this hilly environment were obtained through walking diaries and a survey. The article concludes with suggested directions for the future development of walking accessibility measures along with some ideas about their applicability to the practice of planning and designing a walkable environment.
The real crisis of the church
Authors: Dreyer Wim A.
Published: May 2015

What is the real crisis of the church? Very often, clergy, churches and congregations experience a ‘crisis’ only when membership is in decline, resulting in financial hardship. Crisis is limited to stress which the church as institution experiences when structures, finance and traditions are under pressure. In this contribution, the point is argued that the real crisis of the church is not to be found in institutional challenges, but in the inability of the church to be what it already is. With reference to Karl Barth’s ecclesiology, this contribution departs from the assumption that the real crisis of the church is not only to be found in external circumstances and influences, but is primarily a question of the church not being able to ‘be church’. Continued reformation of the church is of utmost importance.
Woman Wisdom and the ethical vision of the book of Proverbs: An African reflection
Authors: Olojede Funlola O.
Published: May 2015

An observable gap in scholarship is a comprehensive ethical reflection on the portrayal of wisdom as feminine in the book of Proverbs and its implication for wisdom ethics. Besides this lacuna is the observation that the few existing studies on the ethics of the book of Proverbs take their point of departure essentially from a Western conception of ethics. This article as approached the book of Proverbs from an ethical perspective and has argued that the African view of ethics has a rich quality embedded in communitarian values that can be explored heuristically to interpret the ethical vision of the book of Proverbs. Such an approach, it is suggested, has pedagogical relevance to the teaching of biblical ethics especially in Africa.
Intra-Adenoid Cyst: A Case Report with an Immunohistochemical Study and Review of Literature
Authors: Matsumoto Yuma , Yokoi Hidenori , Ikeda Tetsuya , Fujiwara Masachika , Kamma Hiroshi , Kohno Naoyuki
Published: May 2015

A woman in her 50s was referred to our department with the chief complaint of nasal congestion and pharyngeal discomfort. The patient had been diagnosed with sleep apnea at the Department of Internal Medicine, and had undergone nasal continuous positive airway pressure (nCPAP) therapy, but her response to the treatment was poor. A cystic lesion occupying the nasopharynx, which was detected by nasopharyngeal fiberscopy, computed tomography, and magnetic resonance imaging, was thought to be the cause of the nasal congestion, pharyngeal discomfort, and obstructive sleep apnea syndrome (OSAS). Consequently, the patient underwent extirpation of the lesion under general anesthesia for the purpose of obtaining a definitive diagnosis as well as for treatment of the nasopharyngeal tumor. The diagnosis of intra-adenoid cyst was eventually made based on the pathological findings, which revealed lymphoid tissue accompanied by expansion of the crypt, as well as inflammatory cell infiltration with follicular hyperplasia. After the operation, the patient reported subjective improvement of her symptoms, and began to respond to the nCPAP therapy for her sleep apnea syndrome. Nasopharyngeal cysts, in particular adult intra-adenoid cyst, are relatively rare. The outcomes of the current case indicated that the presence of a nasopharyngeal cystic disease was hampering the nCPAP treatment of refractory OSAS.
The Volume Regulation Graph versus the Ejection Fraction as Metrics of Left Ventricular Performance in Heart Failure with and without a Preserved Ejection Fraction: A Mathematical Model Study
Authors: Faes Theo J.C. , Kerkhof Peter L.M.
Published: May 2015

In left ventricular heart failure, often a distinction is made between patients with a reduced and a preserved ejection fraction (EF). As EF is a composite metric of both the end-diastolic volume (EDV) and the end-systolic ventricular volume (ESV), the lucidity of the EF is sometimes questioned. As an alternative, the ESV–EDV graph is advocated. This study identifies the dependence of the EF and the EDV–ESV graph on the major determinants of ventricular performance. Numerical simulations were made using a model of the systemic circulation, consisting of an atrium–ventricle valves combination; a simple constant pressure as venous filling system; and a three-element Windkessel extended with a venous system. ESV–EDV graphs and EFs were calculated using this model while varying one by one the filling pressure, diastolic and systolic ventricular elastances, and diastolic pressure in the aorta. In conclusion, the ESV–EDV graph separates between diastolic and systolic dysfunction while the EF encompasses these two pathologies. Therefore, the ESV–EDV graph can provide an advantage over EF in heart failure studies.
Reversible Cardiomyopathies
Authors: Patel Harsh , Madanieh Raef , Kosmas Constantine E. , Vatti Satya K. , Vittorio Timothy J.
Published: May 2015

Cardiomyopathies (CMs) have many etiological factors that can result in severe structural and functional dysregulation. Fortunately, there are several potentially reversible CMs that are known to improve when the root etiological factor is addressed. In this article, we discuss several of these reversible CMs, including tachycardia-induced, peripartum, inflammatory, hyperthyroidism, Takotsubo, and chronic illness-induced CMs. Our discussion also includes a review on their respective pathophysiology, as well as possible management solutions.
Cannabidiol as an Intervention for Addictive Behaviors: A Systematic Review of the Evidence
Authors: Prud'homme Mélissa , Cata Romulus , Jutras-Aswad Didier
Published: May 2015

Drug addiction is a chronically relapsing disorder characterized by the compulsive desire to use drugs and a loss of control over consumption. Cannabidiol (CBD), the second most abundant component of cannabis, is thought to modulate various neuronal circuits involved in drug addiction. The goal of this systematic review is to summarize the available preclinical and clinical data on the impact of CBD on addictive behaviors. MEDLINE and PubMed were searched for English and French language articles published before 2015. In all, 14 studies were found, 9 of which were conducted on animals and the remaining 5 on humans. A limited number of preclinical studies suggest that CBD may have therapeutic properties on opioid, cocaine, and psychostimulant addiction, and some preliminary data suggest that it may be beneficial in cannabis and tobacco addiction in humans. Further studies are clearly necessary to fully evaluate the potential of CBD as an intervention for addictive disorders.
Discrete harmonic maps and convergence to conformal maps, I: Combinatorial harmonic coordinates
Authors: Hersonsky Sa'ar
Published: May 2015

In this paper, we provide new discrete uniformization theorems for bounded,

m

-connected planar domains. To this end, we consider a planar, bounded,

m

-connected domain

\Omega

, and let

\partial \Omega

be its boundary. Let

\mathcal{T}

denote a triangulation of

\Omega\cup\partial\Omega

. We construct a
new
decomposition of

\Omega\cup\partial\Omega

into a finite union of quadrilaterals with disjoint interiors. The construction is based on utilizing a
pair
of harmonic functions on

{\mathcal T}^{(0)}

and properties of their level curves. In the sequel [26], it will be proved that a particular discrete scheme based on these theorems converges to a conformal map, thus providing an affirmative answer to a question raised by Stephenson [41, Section 11].
Lower bounds for Pythagoras numbers of function fields
Authors: Grimm David
Published: May 2015

We show that the transcendence degree of a real function field over an arbitrary real base field is a strict lower bound for its Pythagoras number and a weak lower bound for all its higher Pythagoras numbers.
Germs of singular Levi-flat hypersurfaces and holomorphic foliations
Authors: Shafikov Rasul , Sukhov Alexandre
Published: May 2015

It is shown that the Levi foliation of a real analytic Levi-flat hypersurface extends to a

d

-web near a nondicritical singular point and admits a multiple-valued meromorphic first integral.
Lottery ticket and instant win ticket gambling: exploring the distinctions
Authors: Short Megan M. , Penney Alexander M. , Mazmanian Dwight , Jamieson John
Published: May 2015

Lottery gambling is the most common form of gambling in Canada, and lottery tickets and instant win tickets are the most frequently played games. Differences between lottery ticket gambling and instant win ticket gambling were examined by using a large-scale Canadian data set (N = 25,780). Lottery ticket gambling was associated with being older, male, and married, whereas instant win ticket gambling was associated with lower levels of education. Frequency of instant win ticket gambling predicted greater problem gambling severity and participating in more gambling activities independent of demographic variables and lottery ticket gambling. In comparison, frequency of lottery ticket gambling did not predict problem gambling severity or the number of gambling activities independent of demographic variables and instant win ticket gambling. Neither lottery game was related to mental health disorders or substance use. These findings provide converging evidence suggesting that different lottery games may attract distinct types of Canadian gamblers.
Proposta de critérios técnicos para a utilização de reesíduos não perigosos
Authors: Lima Couto Maria Claudia , Nogueira Zon Jéssica Luiza , Zuccon Canal Gava Leonardo
Published: May 2015

The mineral extraction is of great importance in the country's economy, generating in-come and employment for the population. But it is a potentially degrading activity, with very striking environmental change, leading to degradation of area, with the removal of non-renewable minerals and leaving pits exhausted with the requirement to be recov-ered. The aim of this study is to propose technical criteria for choosing an area degrad-ed by mining that can be retrieved using waste from mining for your own fulfillment. For this, technical criteria established in normative instruments were analyzed, information about APA Stone Elephant, in Nova Venécia - ES where this technique is being used, as well as a consulting experts who act was performed in the mining area and solid waste management for public agencies and private companies. From the responses obtained appears to be a list containing technical, fundamental criteria for the choice of areas degraded by mining, which can be retrieved using the waste activity itself.
Application of sumac and dried whey in female broiler feed
Authors: Kheiri F. , Rahimian Y. , Nasr J.
Published: May 2015

Abstract. The present study aimed at investigating the effects of sumac and dried whey powder on growth performance, carcass traits, intestinal morphology, microbial population, and some biochemical parameters and antibody titer against Newcastle disease of female broiler chicks. A total of 360 1-day-old female broiler chicks with an average weight of 38 ± 0.42 g were randomly divided into three treatments. Each treatment was further divided into six replicates. Three treatments were used: chicks were fed by basal diet as control group, basal diet + 0.02% sumac powder (S), and basal diet + 0.02% dried whey powder (DW) for 42 days. Results showed that feed intake of chicks increased significantly in S and DW in comparison with the control group (P < 0.05). Body weight gain was also significantly higher in the treated groups. The serum concentration triglyceride and cholesterol of chicks decreased significantly by S and DW feeding. While low-density lipoprotein (LDL) level decreased significantly, high-density lipoprotein (HDL) levels increased in the S group. Antibody level increased titer against Newcastle disease significantly by feeding treated diet compared to the control group. Data from microbial population investigation showed that E. coli population decreased while Lactobacillus increased in S and DW groups. The data revealed an improvement in the body weight gain, feed conversion ratio because of increased intestinal morphology, antibody level, and some useful microbial population in female broiler chicks receiving the sumac and dried whey powder.
Quasi-biennial oscillation of the tropical stratospheric aerosol layer
Authors: Hommel R. , Timmreck C. , Giorgetta M. A. , Graf H. F.
Published: May 2015

Abstract. This study describes how aerosol in an aerosol-coupled climate model of the middle atmosphere is influenced by the quasi-biennial oscillation (QBO) during times when the stratosphere is largely unperturbed by volcanic material. In accordance with satellite observations, the vertical extent of the stratospheric aerosol layer in the tropics is modulated by the QBO by up to 6 km, or ~ 35% of its mean vertical extent between 100–7 hPa (about 16–33 km). Its largest vertical extent lags behind the occurrence of strongest QBO westerlies. The largest reduction lags behind maximum QBO easterlies. Strongest QBO signals in the aerosol surface area (30 %) and number densities (up to 100% e.g. in the Aitken mode) are found in regions where aerosol evaporates, that is above the 10 hPa pressure level (~ 31 km). Positive modulations are found in the QBO easterly shear, negative modulations in the westerly shear. Below 10 hPa, in regions where the aerosol mixing ratio is largest (50–20 hPa, or ~ 20–26 km), in most of the analysed parameters only moderate statistically significant QBO signatures (< 10%) have been found. QBO signatures in the model prognostic aerosol mixing ratio are significant at the 95% confidence level throughout the tropical stratosphere where modelled mixing ratios exceed 0.1 ppbm. In some regions of the tropical lower stratosphere the QBO signatures in other analysed parameters are partly not statistically significant. Peak-to-peak amplitudes of the QBO signature in the prognostic mixing ratios are up to twice as large as seasonal variations in the region where aerosols evaporate and between 70–30 hPa. Between the tropical tropopause and 70 hPa the QBO signature is relatively weak and seasonal variations dominate the variability of the simulated Junge layer. QBO effects on the upper lid of the tropical aerosol layer turn the quasi-static balance between processes maintaining the layer's vertical extent into a cyclic balance when considering this dominant mode of atmospheric variability. Global aerosol-interactive models without a QBO are only able to simulate the quasi-static balance state. To assess the global impact of stratospheric aerosols on climate processes, those partly nonlinear relationships between the QBO and stratospheric aerosols have to be taken into account.
A theoretical study of the effect of subsurface oceanic bubbles on the enhanced aerosol optical depth band over the southern oceans as detected from MODIS and MISR
Authors: Christensen M. , Zhang J. , Reid J. S. , Zhang X. , Hyer E. J. , Smirnov A.
Published: May 2015

Abstract. Submerged oceanic bubbles, which have a much longer life span than whitecaps or bubble rafts, have been hypothesized to increase the water-leaving radiance and thus affect satellite-based estimates of water-leaving radiance to non-trivial levels. This study explores this effect further to determine whether such bubbles are of sufficient magnitude to impact satellite aerosol optical depth (AOD) retrievals through perturbation of the lower boundary conditions. There has been significant discussion in the community regarding the high positive biases in retrieved AODs in many remote ocean regions. In this study, for the first time, the effects of oceanic bubbles on satellite retrievals of AOD are studied by using a linked Second Simulation of a Satellite Signal in the Solar Spectrum (6S) atmospheric and HydroLight oceanic radiative transfer models. The results suggest an insignificant impact on AOD retrievals in regions with near-surface wind speeds of less than 12 m s−1. However, the impact of bubbles on aerosol retrievals could be on the order of 0.02–0.04 for higher wind conditions within the scope of our simulations (e.g., winds < 20 m −1. This bias is propagated to global scales using 1 year of Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer EOS (AMSR-E) data to investigate the possible impacts of oceanic bubbles on an enhanced AOD belt observed over the high-latitude southern oceans (also called the enhanced southern oceans anomaly, or ESOA) by some passive satellite sensors. Ultimately, this study is supportive of the null hypothesis: submerged bubbles are not the major contributor to the ESOA feature. This said, as retrievals progress to higher and higher resolutions, such as from airborne platforms, the uniform bubble correction in clean marine conditions should probably be separately accounted for against individual bright whitecaps and bubble rafts.
Reconstruction of high resolution time series from slow-response broadband solar and terrestrial irradiance measurements by deconvolution
Authors: Ehrlich A. , Wendisch M.
Published: May 2015

Abstract. Broadband solar and terrestrial irradiance measurements of high temporal resolution are needed to study inhomogeneous clouds or surfaces and to derive vertical profiles of heating/cooling rates at cloud top. An efficient method to enhance the temporal resolution of slow-response measurements of broadband irradiance using pyranometer or pyrgeometer is introduced. It is based on the deconvolution theorem of Fourier transform to restore amplitude and phase shift of high frequent fluctuations. It is shown that the quality of reconstruction depends on the instrument noise, the pyrgeometer response time and the frequency of the oscillations. The method is tested in laboratory measurements for synthetic time series including a boxcar function and periodic oscillations using a CGR-4 pyrgeometer with response time of 3 s. The originally slow-response pyrgeometer data were reconstructed to higher resolution and compared to the predefined synthetic time series. The reconstruction of the time series worked up to oscillations of 0.5 Hz frequency and 2 W m−2 amplitude if the sampling frequency of the data acquisition is 16 kHz or higher. For oscillations faster than 2 Hz the instrument noise exceeded the reduced amplitude of the oscillations in the measurements and the reconstruction failed. The method was applied to airborne measurements of upward terrestrial irradiance from the VERDI (Vertical Distribution of Ice in Arctic Clouds) field campaign. Pyrgeometer data above open leads in sea ice and a broken cloud field were reconstructed and compared to KT19 infrared thermometer data. The reconstruction of amplitude and phase shift of the deconvoluted data improved the agreement with the KT19 data. Cloud top temperatures were improved by up to 1 K above broken clouds while an underestimation of 2.5 W m−2 was found for the upward irradiance over small leads when using the slow-response data. The limitations of the method with respect to instrument noise and digitalization of measurements by the data acquisition are discussed.
A re-evaluated Canadian ozonesonde record: measurements of the vertical distribution of ozone over Canada from 1966 to 2013
Authors: Tarasick D. W. , Davies J. , Smit H. G. J. , Oltmans S. J.
Published: May 2015

Abstract. In Canada routine ozone soundings have been carried at Resolute Bay since 1966, making this record the longest in the world. Similar measurements started in the 1970s at three other sites, and the network was expanded in stages to 10 sites by 2003. This important record for understanding long-term changes in tropospheric and stratospheric ozone has been re-evaluated as part of the SPARC/IO3C/IGACO-O3/NDACC (SI2N) initiative. The Brewer–Mast sonde, used in the Canadian network until 1980, is different in construction from the ECC sonde, and the ECC sonde itself has also undergone a variety of minor design changes over the period 1980–2013. Corrections have been made for the estimated effects of these changes, to produce a more homogeneous dataset. The effect of the corrections is generally modest, and so should not invalidate past analyses that have used Canadian network data. However, the overall result is entirely positive: the comparison with co-located total ozone spectrometers is improved, in terms of both bias and SD, and trends in the bias have been reduced or eliminated. An uncertainty analysis (including the additional uncertainty from the corrections, where appropriate) has also been conducted, and the altitude-dependent estimated uncertainty is included with each revised profile. The resulting time series show negative trends in the lower stratosphere of up to 5% decade−1 for the period 1966–2013. Most of this decline occurred before 1997, and linear trends for the more recent period are generally not significant. The time series also show large variations from year to year. Some of these anomalies can be related to cold winters (in the Arctic stratosphere), or changes in the Brewer–Dobson circulation, which may thereby be influencing trends. In the troposphere trends for the 48 year period are small, and for the most part not significant. This suggests that ozone levels in the free troposphere over Canada have not changed significantly in nearly 50 years.
A model of the methane cycle, permafrost, and hydrology of the Siberian continental margin
Authors: Archer D.
Published: May 2015

Abstract. A two-dimensional model of a sediment column, with Darcy fluid flow, biological and thermal methane production, and permafrost and methane hydrate formation, is subjected to glacial–interglacial cycles in sea level, alternately exposing the continental shelf to the cold atmosphere during glacial times and immersing it in the ocean in interglacial times. The glacial cycles are followed by a "long-tail" 100 kyr warming due to fossil fuel combustion. The salinity of the sediment column in the interior of the shelf can be decreased by hydrological forcing to depths well below sea level when the sediment is exposed to the atmosphere. There is no analogous advective seawater-injecting mechanism upon resubmergence, only slower diffusive mechanisms. This hydrological ratchet is consistent with the existence of freshwater beneath the sea floor on continental shelves around the world, left over from the last glacial period. The salt content of the sediment column affects the relative proportions of the solid and fluid H2O-containing phases, but in the permafrost zone the salinity in the pore fluid brine is a function of temperature only, controlled by equilibrium with ice. Ice can tolerate a higher salinity in the pore fluid than methane hydrate can at low pressure and temperature, excluding methane hydrate from thermodynamic stability in the permafrost zone. The implication is that any methane hydrate existing today will be insulated from anthropogenic climate change by hundreds of meters of sediment, resulting in a response time of thousands of years. The strongest impact of the glacial–interglacial cycles on the atmospheric methane flux is due to bubbles dissolving in the ocean when sea level is high. When sea level is low and the sediment surface is exposed to the atmosphere, the atmospheric flux is sensitive to whether permafrost inhibits bubble migration in the model. If it does, the atmospheric flux is highest during the glaciating, sea level regression (soil-freezing) part of the cycle rather than during deglacial transgression (warming and thawing). The atmospheric flux response to a warming climate is small, relative to the rest of the methane sources to the atmosphere in the global budget, because of the ongoing flooding of the continental shelf. The increased methane flux due to ocean warming could be completely counteracted by a sea level rise of tens of meters on millennial timescales due to the loss of ice sheets, decreasing the efficiency of bubble transit through the water column. The model results give no indication of a mechanism by which methane emissions from the Siberian continental shelf could have a significant impact on the near-term evolution of Earth's climate, but on millennial timescales the release of carbon from hydrate and permafrost could contribute significantly to the fossil fuel carbon burden in the atmosphere–ocean–terrestrial carbon cycle.
Vegetation and elevation influence the timing and magnitude of soil CO2 efflux in a humid, topographically complex watershed
Authors: Atkins J. W. , Epstein H. E. , Welsch D. L.
Published: May 2015

Abstract. In topographically complex watersheds, landscape position and vegetation heterogeneity can alter the soil water regime through both lateral and vertical redistribution, respectively. These alterations of soil moisture may have significant impacts on the spatial heterogeneity of biogeochemical cycles throughout the watershed. To evaluate how landscape position and vegetation heterogeneity affect soil CO2 efflux (FSOIL), we conducted observations across the Weimer Run watershed (373 ha), located near Davis, West Virginia, for three growing seasons with varying precipitation. An apparent soil temperature threshold of 11 °C for FSOIL at 12 cm depth was observed in our data, where FSOIL rates greatly increase in variance above this threshold. We therefore focus our analyses of FSOIL on instances in which soil temperature values were above this threshold. Vegetation had the greatest effect on FSOIL rates, with plots beneath shrubs at all elevations, for all years, showing the greatest mean rates of FSOIL (6.07 μmol CO2 m−2 s−1) compared to plots beneath closed-forest canopy (4.69 μmol CO2 m−2 s−1) and plots located in open, forest gap (4.09 μmol CO2 m−2 s−1) plots. During periods of high soil moisture, we find that CO2 efflux rates are constrained, and that maximum efflux rates occur during periods of average to below-average soil water availability. While vegetation was the variable most related to FSOIL, there is also strong interannual variability in fluxes determined by the interaction of annual precipitation and topography. These findings add to the current theoretical constructs related to the interactions of moisture and vegetation in biogeochemical cycles within topographically complex watersheds.
Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization
Authors: Comas X. , Terry N. , Slater L. , Warren M. , Kolka R. , Kristiyono A. , Sudiana N. , Nurjaman D. , Darusman T.
Published: May 2015

Abstract. Current estimates of carbon (C) storage in peatland systems worldwide indicate that tropical peatlands comprise about 15% of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness, volume and C content. We combined a set of indirect geophysical methods (ground-penetrating radar, GPR, and electrical resistivity imaging, ERI) with direct observations using core sampling and C analysis to determine how geophysical imaging may enhance traditional coring methods for estimating peat thickness and C storage in a tropical peatland system in West Kalimantan, Indonesia. Both GPR and ERI methods demonstrated their capability to estimate peat thickness in tropical peat soils at a spatial resolution not feasible with traditional coring methods. GPR is able to capture peat thickness variability at centimeter-scale vertical resolution, although peat thickness determination was difficult for peat columns exceeding 5 m in the areas studied, due to signal attenuation associated with thick clay-rich transitional horizons at the peat–mineral soil interface. ERI methods were more successful for imaging deeper peatlands with thick organomineral layers between peat and underlying mineral soil. Results obtained using GPR methods indicate less than 3% variation in peat thickness (when compared to coring methods) over low peat–mineral soil interface gradients (i.e., below 0.02°) and show substantial impacts in C storage estimates (i.e., up to 37 MgC ha−1 even for transects showing a difference between GPR and coring estimates of 0.07 m in average peat thickness). The geophysical data also provide information on peat matrix attributes such as thickness of organomineral horizons between peat and underlying substrate, the presence of buried wood, buttressed trees or tip-up pools and soil type. The use of GPR and ERI methods to image peat profiles at high resolution can be used to further constrain quantification of peat C pools and inform responsible peatland management in Indonesia and elsewhere in the tropics.
An improved representation of physical permafrost dynamics in the JULES land-surface model
Authors: Chadburn S. , Burke E. , Essery R. , Boike J. , Langer M. , Heikenfeld M. , Cox P. , Friedlingstein P.
Published: May 2015

Abstract. It is important to correctly simulate permafrost in global climate models, since the stored carbon represents the source of a potentially important climate feedback. This carbon feedback depends on the physical state of the permafrost. We have therefore included improved physical permafrost processes in JULES (Joint UK Land Environment Simulator), which is the land-surface scheme used in the Hadley Centre climate models. The thermal and hydraulic properties of the soil were modified to account for the presence of organic matter, and the insulating effects of a surface layer of moss were added, allowing for fractional moss cover. These processes are particularly relevant in permafrost zones. We also simulate a higher-resolution soil column and deeper soil, and include an additional thermal column at the base of the soil to represent bedrock. In addition, the snow scheme was improved to allow it to run with arbitrarily thin layers. Point-site simulations at Samoylov Island, Siberia, show that the model is now able to simulate soil temperatures and thaw depth much closer to the observations. The root mean square error for the near-surface soil temperatures reduces by approximately 30%, and the active layer thickness is reduced from being over 1 m too deep to within 0.1 m of the observed active layer thickness. All of the model improvements contribute to improving the simulations, with organic matter having the single greatest impact. A new method is used to estimate active layer depth more accurately using the fraction of unfrozen water. Soil hydrology and snow are investigated further by holding the soil moisture fixed and adjusting the parameters to make the soil moisture and snow density match better with observations. The root mean square error in near-surface soil temperatures is reduced by a further 20% as a result.