Van Der Werf Research Articles

A global 3-D CTM evaluation of black carbon in the Tibetan Plateau

Abstract. We systematically evaluate the black carbon (BC) simulations for 2006 over the Tibetan Plateau by a global 3-D chemical transport model (CTM) (GEOS-Chem) driven by GEOS-5 assimilated meteorological fields, using in situ measurements of BC in surface air, BC in snow, and BC absorption aerosol optical depth (AAOD). Using improved anthropogenic BC emission inventories for Asia that account for rapid technology renewal and energy consumption growth (Zhang et al., 2009; Lu et al., 2011) and improved global biomass burning emission inventories that account for small fires (van der Werf et al., 2010; Randerson et al., 2012), we find that model results of both BC in surface air and in snow are statistically in good agreement with observations (biases < 15%) away from urban centers. Model results capture the seasonal variations of the surface BC concentrations at rural sites in the Indo-Gangetic Plain, but the observed elevated values in winter are absent. Modeled surface-BC concentrations are within a factor of 2 of the observations at remote sites. Part of the discrepancy is explained by the deficiencies of the meteorological fields over the complex Tibetan terrain. We find that BC concentrations in snow computed from modeled BC deposition and GEOS-5 precipitation are spatiotemporally consistent with observations (r = 0.85). The computed BC concentrations in snow are a factor of 2–4 higher than the observations at several Himalayan sites because of excessive BC deposition. The BC concentrations in snow are biased low by a factor of 2 in the central plateau, which we attribute to the absence of snow aging in the CTM and strong local emissions unaccounted for in the emission inventories. Modeled BC AAOD is more than a factor of 2 lower than observations at most sites, particularly to the northwest of the plateau and along the southern slopes of the Himalayas in winter and spring, which is attributable in large part to underestimated emissions and the assumption of external mixing of BC aerosols in the model. We find that assuming a 50% increase of BC absorption associated with internal mixing reduces the bias in modeled BC AAOD by 57% in the Indo-Gangetic Plain and the northeastern plateau and to the northeast of the plateau, and by 16% along the southern slopes of the Himalayas and to the northwest of the plateau. Both surface BC concentration and AAOD are strongly sensitive to anthropogenic emissions (from China and India), while BC concentration in snow is especially responsive to the treatment of BC aerosol aging. We find that a finer model resolution (0.5° × 0.667° nested over Asia) reduces the bias in modeled surface-BC concentration from 15 to 2%. The large range and non-homogeneity of discrepancies between model results and observations of BC across the Tibetan Plateau undoubtedly undermine current assessments of the climatic and hydrological impact of BC in the region and thus warrant imperative needs for more extensive measurements of BC, including its concentration in surface air and snow, AAOD, vertical profile and deposition.

Influence of emission-factor uncertainty and farm-characteristic variability in LCA estimates of environmental impacts of French dairy farms

Life Cycle Assessment (LCA) is a useful framework for environmental assessment; however, the reliability of LCA results suffers from many sources of uncertainty and variability. Now that systematic uncertainty analysis in LCA is recommended, it can be useful to revisit past LCA studies to see whether inclusion of uncertainty (or additional types of it) changes interpretation of their results. In this study, we added uncertainty in 67 emission factors (EFs) to the variability in farm characteristics of 47 French dairy farms analyzed in a previous LCA study (van der Werf et al., 2009). We propagated uncertainty in EFs with Monte-Carlo simulation to estimate contributions of uncertainty and variability to uncertainty in potential climate change, acidification, and eutrophication impacts. For individual farms, uncertainty in emission factors added uncertainty to the farm's formerly deterministic impacts (coefficients of variation of 2–7% for climate change, 4–11% for acidification, and 2–46% for eutrophication). By farm type (conventional vs. organic), the addition of uncertainty in EFs increased uncertainty in impacts. Although uncertainty in emission factors contributed less to impact uncertainty than variability in farm characteristics did, it did add enough to potentially change decisions about whether differences in certain impacts between farm types were significant, depending upon the significance level and functional unit chosen. Variance-based sensitivity analysis identified emission source categories whose uncertainty contributed most to the uncertainty in impacts: manure deposited in pasture for climate change, cattle housing and manure storage for acidification, and leachate for eutrophication. Although larger uncertainties in potential impacts decrease apparent differences between the systems or scenarios studied, considering more than one type of uncertainty provides decision makers with a more complete and realistic assessment of the state of knowledge. Based on the degree of uncertainty in impacts, they can decide which location on impact intervals (e.g., mean, lower limit, upper limit) is best suited for decisions in a given system. Future studies should explore additional methods to combine multiple sources of uncertainty in LCA and express their relative influences on potential impacts.

Genomic evaluation of both purebred and crossbred performances

BackgroundFor a two-breed crossbreeding system, Wei and van der Werf presented a model for genetic evaluation using information from both purebred and crossbred animals. The model provides breeding values for both purebred and crossbred performances. Genomic evaluation incorporates marker genotypes into a genetic evaluation system. Among popular methods are the so-called single-step methods, in which marker genotypes are incorporated into a traditional animal model by using a combined relationship matrix that extends the marker-based relationship matrix to non-genotyped animals. However, a single-step method for genomic evaluation of both purebred and crossbred performances has not been developed yet.ResultsAn extension of the Wei and van der Werf model that incorporates genomic information is presented. The extension consists of four steps: (1) the Wei van der Werf model is reformulated using two partial relationship matrices for the two breeds; (2) marker-based partial relationship matrices are constructed; (3) marker-based partial relationship matrices are adjusted to be compatible to pedigree-based partial relationship matrices and (4) combined partial relationship matrices are constructed using information from both pedigree and marker genotypes. The extension of the Wei van der Werf model can be implemented using software that allows inverse covariance matrices in sparse format as input.ConclusionsA method for genomic evaluation of both purebred and crossbred performances was developed for a two-breed crossbreeding system. The method allows information from crossbred animals to be incorporated in a coherent manner for such crossbreeding systems.

Differential brain structural correlates of insomnia in depression vs. anxiety

Introduction Insomnia is common in many psychiatric disorders (1), especially so in affective disorders like major depressive disorder (MDD) (2) and anxiety disorder (2,3). Insomnia is moreover a cardinal risk factor for the development of MDD (4). Nevertheless, the neural correlates of insomnia complaints in psychiatric patients have hardly been investigated, hampering the development of rational treatment and prevention of these disabling symptoms. materials and methods Fifty-nine patients with MDD as well as 61 patients with anxiety disorder filled out the Women’s Health Initiative Insomnia Rating Scale (WHIIRS) (5) and underwent structural magnetic resonance imaging of the brain. The WHIIRS is a brief, five-item scale evaluating insomnia symptoms, which yields a summary score that reflects complaints on sleep quality. Whole-brain voxel-based morphometry was used to investigate the association of the WHIIRS summary score with gray matter density. Results In patients with MDD, the WHIIRS insomnia severity score showed a strong negative correlation with gray matter density in the pulvinar of the thalamus. Gray matter in this area showed no association at all with insomnia severity in patients with anxiety disorder. In contrast, anxiety disorder patients more severe insomnia showed lower frontopolar GM density, an association not found in MDD patients. Conclusion This is the first study to directly compare structural brain correlates of insomnia severity between MDD and anxiety disorder. Unlike previous voxel-based morphometry findings that indicated particularly orbitofrontal involvement in sleep complaints in both well-sleeping (6) and poorly-sleeping (7) people without psychiatric disorder, we here found differential involvement of the pulvinar and frontopolar cortex. These triple dissociations have strong implications for our understanding of insomnia; depending on the psychiatric phenotype, remarkably different cerebral mechanisms can underlie seemingly similar subjective sleep complaints.

Acid-suppressive drug use in pregnancy and the toddler's asthma risk: A crossover, case-control study

Acid-suppressive drug use in pregnancy and the toddler's asthma risk: A crossover, case-control study

Genomic Selection: Status in Different Species and Challenges for Breeding

Technical advances and development in the market for genomic tools have facilitated access to whole-genome data across species. Building-up on the acquired knowledge of the genome sequences, large-scale genotyping has been optimized for broad use, so genotype information can be routinely used to predict genetic merit. Genomic selection (GS) refers to the use of aggregates of estimated marker effects as predictors which allow improved individual differentiation at young age. Realizable benefits of GS are influenced by several factors and vary in quantity and quality between species. General characteristics and challenges of GS in implementation and routine application are described, followed by an overview over the current status of its use, prospects and challenges in important animal species. Genetic gain for a particular trait can be enhanced by shortening of the generation interval, increased selection accuracy and increased selection intensity, with species- and breed-specific relevance of the determinants. Reliable predictions based on genetic marker effects require assembly of a reference for linking of phenotype and genotype data to allow estimation and regular re-estimation. Experiences from dairy breeding have shown that international collaboration can set the course for fast and successful implementation of innovative selection tools, so genomics may significantly impact the structures of future breeding and breeding programmes. Traits of great and increasing importance, which were difficult to improve in the conventional systems, could be emphasized, if continuous availability of high-quality phenotype data can be assured. Equally elaborate strategies for genotyping and phenotyping will allow tailored approaches to balance efficient animal production, sustainability, animal health and welfare in future.

Motional sideband excitation using rotating electric fields

A form of motional sideband excitation is described in which a rotating dipole electric field is applied asymmetrically onto a Penning-type trap in the presence of a mechanism for cooling the axial motion of the trapped particles. In contrast to the traditional motional sideband excitation, which uses an oscillating electric field, the rotating field results in only one active sideband in each sense of rotation and so avoids accidental excitation of the other sideband making it applicable to Penning-type traps with a large degree of anharmonicity. Expressions are derived for the magnetron radius expansion and compression rates attainable, and approximations are made for the case of strong and weak drives. A comparison is made with data, taken using a two-stage positron accumulator presented by Isaac et al. [C. A. Isaac, C. J. Baker, T. Mortensen, D. P. van der Werf, and M. Charlton, Phys. Rev. Lett. 107, 033201 (2011)], showing good agreement between the model and experiment.

Structural and Functional Characterization of K339T Substitution Identified in the PB2 Subunit Cap-binding Pocket of Influenza A Virus

Influenza virus RNA-dependent RNA polymerase is a heterotrimer composed of PA, PB1, and PB2 subunits. RNA-dependent RNA polymerase is required for both transcription and replication of influenza viral RNA taking place in the nucleus of infected cells. A "cap-snatching" mechanism is used to generate a 5'-capped primer for transcription in which the cap-binding domain of PB2 (PB2cap) captures the 5' cap of the host pre-mRNA. Our statistical analysis of PB2 sequences showed that residue Lys(339) located in the cap-binding pocket of H5N1 PB2cap was gradually replaced by Thr(339) over the past decade. To understand the role of this amino acid polymorphism, we solved the crystal structures of PB2cap with or without a pre-mRNA cap analog, m(7)GTP, in the presence of Lys(339) or Thr(339). The structures showed that Lys(339) contributes to binding the γ-phosphate group of m(7)GTP, and the replacement of Lys(339) by Thr eliminates this interaction. Isothermal titration calorimetry analysis showed that Thr(339) attenuated the PB2cap cap binding activity in vitro compared with Lys(339). Further functional studies confirmed that Thr(339)-PB2-containing ribonucleoprotein complex has a reduced influenza polymerase activity and RNA synthesis activity, and a reconstituted H5N1 virus containing the Thr(339) substitution exhibited a lower virulence to mice but more active replication in Madin-Darby canine kidney cells. The K339T substitution in the cap-binding pocket of PB2 modulates the polymerase activity and virulence by regulating the cap binding activity. It is informative to track variations in the cap-binding pocket of PB2 in surveillance of the evolution and spread of influenza virus.

Uncertainties and REDD+: Implications of applying the conservativeness principle to carbon stock estimates

Relatively small periodic carbon (C) stock changes at national levels through forest loss and forest degradation contribute, in sum, a substantial 12–15 % to worldwide C emissions (van der Werf et al. 2009). However, a reliable quantification of C stock changes remains difficult. Existing C stocks are fortunately still large; this means that even small relative survey errors can lead to substantial absolute errors in C stock estimates, which may even exceed their periodic changes. This fact makes reporting achieved emission reductions on a credible basis difficult. In this issue, Plugge et al. draw our attention to this important problem through elaborating the effects which uncertainties may have on REDD+ C accounting. REDD+, a mechanism for reducing emissions from deforestation and forest degradation, which has now been extended to include conservation, management, and enhancement of forest carbon stocks (thus REDD+), is intended to reward developing countries for the mitigation of greenhouse gas emissions (UNFCC 2010). The implementation of effective REDD+ mechanisms requires credibility of the emission reductions achieved. To accomplish the necessary credibility Plugge et al. (this issue) propose using the principle of conservativeness to guarantee emission reductions. Inspired by their paper, I will develop some considerations of my own in an attempt to broaden the discussion on possible implications of an implementation of the conservativeness approach.

Recall deficits in stroke patients with thalamic lesions covary with damage to the parvocellular mediodorsal nucleus of the thalamus

The functional role of the mediodorsal thalamic nucleus (MD) and its cortical network in memory processes is discussed controversially. While Aggleton and Brown (1999) suggested a role for recognition and not recall, Van der Werf et al. (2003) suggested that this nucleus is functionally related to executive function and strategic retrieval, based on its connections to the prefrontal cortices (PFC). The present study used a lesion approach including patients with focal thalamic lesions to examine the functions of the MD, the intralaminar nuclei and the midline nuclei in memory processing. A newly designed pair association task was used, which allowed the assessment of recognition and cued recall performance.Volume loss in thalamic nuclei was estimated as a predictor for alterations in memory performance. Patients performed poorer than healthy controls on recognition accuracy and cued recall. Furthermore, patients responded slower than controls specifically on recognition trials followed by successful cued recall of the paired associate. Reduced recall of picture pairs and increased response times during recognition followed by cued recall covaried with the volume loss in the parvocellular MD. This pattern suggests a role of this thalamic region in recall and thus recollection, which does not fit the framework proposed by Aggleton and Brown (1999). The functional specialization of the parvocellular MD accords with its connectivity to the dorsolateral PFC, highlighting the role of this thalamocortical network in explicit memory (Van der Werf et al., 2003).

Integration of technology and science education: A collaborative workshop for instructors

This workshop focuses on the benefits and challenges of incorporating digital education technology into 21st century undergraduate science education. Students and faculty alike are adapting to a new, more technologically driven paradigm of pedagogy in the ‘classroom.’ In The College of 2020: Students (2009), Van Der Werf and Sabatier predict this shift will continue in a variety of manners: greater student access of online courses, improved access via portable computing devices, greater connectivity and creativity from colleges, personalization of education, exploring concepts through games and simulations, among other pedagogical changes. Scientific organizations, publishing companies, and technology companies are driving many of these technological innovations. Research is starting to emerge on the pedagogical effectiveness of digital education resources, although no clear, definitive relationship has been identified. The goals of this workshop are to discuss: 1) how digital education resources can be leveraged to complement and enhance traditional science education pedagogical approaches, and 2) preliminary results of studies identifying the resources anatomy and physiology students find most effective for studying and learning. Digital content from McGraw‐Hill Higher Education as utilized by two faculty members in their A&P courses will be discussed as part of the preliminary research.

Phosphatidylinositol 4-Kinase IIIβ Is Required for Severe Acute Respiratory Syndrome Coronavirus Spike-mediated Cell Entry

Phosphatidylinositol kinases (PI kinases) play an important role in the life cycle of several viruses after infection. Using gene knockdown technology, we demonstrate that phosphatidylinositol 4-kinase IIIβ (PI4KB) is required for cellular entry by pseudoviruses bearing the severe acute respiratory syndrome-coronavirus (SARS-CoV) spike protein and that the cell entry mediated by SARS-CoV spike protein is strongly inhibited by knockdown of PI4KB. Consistent with this observation, pharmacological inhibitors of PI4KB blocked entry of SARS pseudovirions. Further research suggested that PI4P plays an essential role in SARS-CoV spike-mediated entry, which is regulated by the PI4P lipid microenvironment. We further demonstrate that PI4KB does not affect virus entry at the SARS-CoV S-ACE2 binding interface or at the stage of virus internalization but rather at or before virus fusion. Taken together, these results indicate a new function for PI4KB and suggest a new drug target for preventing SARS-CoV infection.

National database for calculating fuel available to wildfires

In recent years, wildfires have emerged as an important part of the global environment. Carbon released from fires during combustion alters the global carbon balance. Smoke emissions are a health hazard to nearby communities [Wegesser et al., 2009], can impair air quality and visibility for hundreds of kilometers downwind (Interagency Modeling of Protected Visual Environments; http://vista.cira.colostate.edu/improve/Data/IMPROVE/improve_data.htm , 2004), and contribute substantially to the global aerosol budget [van der Werf et al., 2006]. As understanding about fire as a global ecosystem process improves [Bowman et al., 2009] and as more and more global fire databases are being built [Giglio et al., 2009], wildfires are increasingly emerging as an important component of Earth system models, particularly those that involve emissions from fires and their effects on climate.

Biomass Burning: Observations, Modeling, and Data Assimilation

wHat: Junior faculty with diverse backgrounds in the physical sciences met with senior scientists in the field of biomass burning to discuss current science and near-term research problems in the study of fire emissions. wHEn: 13–15 July 2010 wHErE: Boulder, Colorado F ires affect the Earth system in multiple ways. They are a major source of aerosol particles, greenhouse gases, and other trace constituents in the atmosphere (Crutzen and Andreae 1990; Seiler and Crutzen 1980). They alter the exchanges of matter and energy between the land surface and the atmosphere, with important implications for local, regional, and global environmental patterns. Moreover, fires play a significant role in affecting air quality, the ecosystem, land use, public health, and safety. To understand the role of fires in changing climate conditions and socioeconomic landscapes, recent scientific studies of biomass burning have focused on two goals: i) quantifying the emissions of aerosol particles and trace gases from fires and improving the description of spatial and temporal patterns at mesoscale or finer resolutions and ii) characterizing and understanding the effect of these emissions on atmospheric processes at various scales, ranging from human health and air quality impacts at a local scale to cloud properties and precipitation at a regional scale to interactions with Earth’s climate on a decadal scale. The last decade has seen significant progress toward both goals. Estimates of fire emissions have been greatly improved by better, more comprehensive satellite observations. Global emission inventories are now routinely updated, some in near–real time, with the spatial resolution on the order of kilometers to tens of kilometers and temporal sampling on the order of hourly to a few days (e.g., Reid et al. 2009; van der Werf et al. 2010). Equally dramatic advances have been made in the numerical simulation of the transport and evolution of smoke-related species, which feature both higher resolution and improved descriptions of relevant dynamic and chemical processes. These scientific advances have also benefited from rapid growth in computational power, extensive and detailed laboratory experiments, improved access to ground-based observation networks, and numerous intensive field campaigns. This richness of observations, combined with improvements in atmospheric simulations, has driven broad-based research programs at institutions around the globe aimed at understanding the role of fire in the Earth system. However, large uncertainties remain in our description of the magnitude, patterns, and drivers of AffiliAtions: HyEr—marine meteorology Division, naval research Laboratory, monterey, California; wang— Department of Earth and atmospheric sciences, university of nebraska, Lincoln, nebraska; arEllano—Department of atmospheric sciences, university of arizona, Tucson, arizona Corresponding Author: Edward J. Hyer, naval research Laboratory, 7 grace Hopper avenue, monterey, Ca 93943 E-mail: edward.hyer@nrlmry.navy.mil

Examination of the Suspended Sediment Concentration Formulae Using Full-Scale Rippled Bed and Sheet-Flow Data

A set of theoretical models is deduced for computing suspended sediment concentration in coastal waters under the influence of suspension on the bottom boundary layer due to turbulent motion over full-scale sand ripples and sheet-flow, following on from the work of Jayaratne and Shibayama [2007]. Dimensional analysis and best-fit technique are the main methods for the formulation of reference concentrations and vertical distribution of diffusion coefficients of the models. Model parameters (e.g. calibration coefficients) are calibrated with the help of full-scale measured data. Time-averaged concentration profiles are derived from the steady diffusion equation. Two distinct suspension layers (i.e., lower and upper) were identified within the suspension over rippled bed, therefore predictive models were given separately for each layer. In the case of sheet-flow regime, predictive models were given for suspension and upper-sheet-flow layers. Published experimental data from 4 different data sources in the SANTOSS database (75 and 80 full-scale experiments for rippled bed and sheet-flow regimes respectively) from 1994 to 2007 [Van der Werf et al., 2009] are better explained by the proposed formulae, however different sets of calibration coefficients were assigned in each data set primarily due to the flow type (regular or irregular flows) and nature of the laboratory experiments (wave flume and wave tunnel).

Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe

[1] Croplands cover 12% of the ice‐free land surface and play an important role in the global carbon cycle. Light use efficiency (LUE) models have often been employed to estimate the exchange of CO2 between croplands and the atmosphere. A key parameter in these models is the maximum light use efficiency (*), but estimates of * vary by at least a factor 2. Here we used 12 agricultural eddy‐ flux measurement sites in North America and Europe to constrain LUE models in general and *i n particular. We found that LUE models could explain on average about 70% of the variability in net ecosystem exchange (NEE) when we increased the * from 0.5 to 0.65–2.0g C per MJ Photosynthetic Active Radiation (PAR). Our results imply that croplands are more important in the global carbon budget than often thought. In addition, inverse modeling approaches that utilize LUE model outputs as a‐priori input may have to be revisited in areas where croplands are an important contributor to regional carbon fluxes. Citation: Chen, T., G. R. van der Werf, A. J. Dolman, and M. Groenendijk (2011), Evaluation of cropland maximum light use efficiency using eddy flux measurements in North America and Europe, Geophys. Res. Lett., 38, L14707,

Current Concepts in the Management of Tuberculosis

Tuberculosis (TB) poses a serious threat to public health throughout the world but disproportionately afflicts low-income nations. Persons in close contact with a patient with active pulmonary TB and those from endemic regions of the world are at highest risk of primary infection, whereas patients with compromised immune systems are at highest risk of reactivation of latent TB infection (LTBI). Tuberculosis can affect any organ system. Clinical manifestations vary accordingly but often include fever, night sweats, and weight loss. Positive results on either a tuberculin skin test or an interferon-γ release assay in the absence of active TB establish a diagnosis of LTBI. A combination of epidemiological, clinical, radiographic, microbiological, and histopathologic features is used to establish the diagnosis of active TB. Patients with suspected active pulmonary TB should submit 3 sputum specimens for acid-fast bacilli smears and culture, with nucleic acid amplification testing performed on at least 1 specimen. For patients with LTBI, treatment with isoniazid for 9 months is preferred. Patients with active TB should be treated with multiple agents to achieve bacterial clearance, to reduce the risk of transmission, and to prevent the emergence of drug resistance. Directly observed therapy is recommended for the treatment of active TB. Health care professionals should collaborate, when possible, with local and state public health departments to care for patients with TB. Patients with drug-resistant TB or coinfection with human immunodeficiency virus should be treated in collaboration with TB specialists. Public health measures to prevent the spread of TB include appropriate respiratory isolation of patients with active pulmonary TB, contact investigation, and reduction of the LTBI burden.

Is pre-commercial thinning compatible with carbon sequestration? A case study in a maritime pine stand in northwestern Spain

Fire is one of the greatest potential risks to loss of stored terrestrial C (Kashian et al., 2006; van der Werf et al., 2006; Wiedinmyer and Neff, 2007) and is a loss pathway that is difficult to quantify because of the high degree of spatial and temporal variation in fire emissions (Wiedinmyer and Neff, 2007). Pulsed emissions of CO2 during fires are assumed to be partly counterbalanced via the uptake of CO2 by regrowing vegetation in the decades following fire (Wiedinmyer and Neff, 2007). In forests of the Iberian Peninsula, where wildfire is a major and frequent perturbation, the post-fire recovery rate may be important in regional scale carbon storage because carbon lost in stand-replacing fires is often a significant component of regional carbon budgets (Kashian et al., 2006; Wiedinmyer and Neff, 2007). Short-term effects of fire will be important for the carbon balance in this century because the expected higher fire frequency (Ministerio de Medio Ambiente, 2005; Vega et al., 2009) will release large amounts of carbon through combustion, and increase the forested area with negative net ecosystem production (Litton et al., 2004; Kashian et al., 2006; van der Werf et al., 2006; Wiedinmyer and Neff, 2007). Moreover, depending on the forest type, the area burned by a stand-replacing fire may not recover its pre-fire C stock for decades (Wirth et al., 2002). In postfire regenerated stands, thinning and shrub removal may have a significant impact on the magnitude of net carbon fluxes, with conversion of the ecosystem from a sink to a source of CO2 in the short term (Misson et al., 2005; Hurteau et al., 2008; Hurteau and North, 2009). In this context, it is important to quantify the effects of thinning of heavily stocked fire-origin stands on carbon accumulation in trees. Available information on this topic is still Is pre-commercial thinning compatible with carbon sequestration? A case study in a maritime pine stand in northwestern Spain

APPLICABILITY OF THE PREDICTIVE FORMULAE FOR SUSPENDED SEDIMENT CONCENTRATION ON FULL-SCALE RIPPLED BED AND SHEET FLOW

A significant proportion of the sediment transported in coastal waters consists of sand, which moves in suspension. Transport of sediment suspension in and outside the surf zone occurs predominantly due to vortical motion over wave-generated sand ripples, from sheet flow layer and turbulence under breaking waves. A new set of explicit theoretical formulae was deduced to predict sediment concentration over full-scale rippled beds and sheet flows from the predictive models given in Jayaratne and Shibayama (2007). Previous predictive models were derived using 325 test cases from 1977-1996. The new formulae were also established using dimensional analysis and a best-fit technique. Parameterisation of formulae was carried out with the help of large-scale wave, sediment and concentration data appeared in SANTOSS database (see Van der Werf et al., 2009) which covered 298 test cases from 1987-2007. Reference level was taken where the concentration could be measured without affecting the bed.
 
 Formulae for predicting bed reference concentration (ca), diffusion coefficient (εs) and concentration profile [c(z)] on full-scale rippled bed and sheet flow from Jayaratne and Shibayama (2007) were initially assessed with the new datasets. It was identified that the measured and predicted concentration do not agree well in magnitudes and distribution profile since the measured field-scale wave tunnel data have stronger bed shear effect than in the wave flume data used for the previous formulation. Therefore, some variables in previous equations were replaced appropriately with suitable parameters such as Shields parameter with the mobility number (ψ) etc. Bed reference levels (z0) were adjusted based on the value of ca. Empirical constants and exponents in those equations were carefully modified in order to match the measured values using the regression analysis. The applicability of modified empirical formulae on full-scale rippled bed and sheet flow depends highly on z and ψ. Two different suspension regions were identified within the datasets over the rippled beds due to the enhanced mixing processes in the upper layer and the coherent vortex structure in the osillatory boundary layer, hence two types of equations were proposed. Conversely, four distinct suspension regimes were identified over full-scale sheet flow and predictive models were given for upper sheet flow (exponential) and suspension layers (power relationship). The cause for this different behaviour was identified as the presence of different mixing processes in the upper sheet flow and suspension layer. 
 
 REFERENCES
 Jayaratne, M.P.R. and Shibayama, T. (2007). Suspended sediment concentration on beaches under three different mechanisms, Coastal Engineering Journal, 49(4), 357-392.
 
 Van der Werf, J.J., Schretlen, J.J.L.M., Ribberink, J.S. and O'Donoghue, T. (2009). Database of full-scale laboratory experiments on wave-driven sand transport processes, Coastal Engineering, 56, 726-732.

Response to Letter Regarding Article, “Peripartum Cardiomyopathy as a Part of Familial Dilated Cardiomyopathy”

HomeCirculationVol. 123, No. 2Response to Letter Regarding Article, “Peripartum Cardiomyopathy as a Part of Familial Dilated Cardiomyopathy” Free AccessReplyPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReplyPDF/EPUBResponse to Letter Regarding Article, “Peripartum Cardiomyopathy as a Part of Familial Dilated Cardiomyopathy” Karin Y. van Spaendonck-Zwarts, J. Peter van Tintelen and Jan D.H. Jongbloed Dirk J. van Veldhuisen, Rik van der Werf and Maarten P. van den Berg Walter J. Paulus Dennis Dooijes Karin Y. van Spaendonck-ZwartsKarin Y. van Spaendonck-Zwarts Department of GeneticsUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Spaendonck-Zwarts, van Tintelen, Jongbloed) Search for more papers by this author , J. Peter van TintelenJ. Peter van Tintelen Department of GeneticsUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Spaendonck-Zwarts, van Tintelen, Jongbloed) Search for more papers by this author and Jan D.H. JongbloedJan D.H. Jongbloed Department of GeneticsUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Spaendonck-Zwarts, van Tintelen, Jongbloed) Search for more papers by this author Dirk J. van VeldhuisenDirk J. van Veldhuisen Department of CardiologyUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Veldhuisen, van der Werf, van den Berg) Search for more papers by this author , Rik van der WerfRik van der Werf Department of CardiologyUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Veldhuisen, van der Werf, van den Berg) Search for more papers by this author and Maarten P. van den BergMaarten P. van den Berg Department of CardiologyUniversity Medical Centre GroningenUniversity of GroningenGroningen, the Netherlands (van Veldhuisen, van der Werf, van den Berg) Search for more papers by this author Walter J. PaulusWalter J. Paulus Department of PhysiologyFree University Medical CentreAmsterdam, the Netherlands (Paulus) Search for more papers by this author Dennis DooijesDennis Dooijes Department of GeneticsErasmus Medical CentreRotterdam, the Netherlands (Dooijes) Search for more papers by this author Originally published18 Jan 2011https://doi.org/10.1161/CIRCULATIONAHA.110.984971Circulation. 2011;123:e9We thank Dr Baruteau et al for their comments. They raise an important issue, and recommend cardiological screening in all first-degree relatives of patients with peripartum cardiomyopathy (PPCM), not only when it concerns PPCM without recovery.Our findings strongly suggested that a subset of PPCM is part of the spectrum of familial dilated cardiomyopathy.1 The article by Morales et al2 in the same issue of Circulation underscores this. Taking these new data into account, we consider the genetic susceptibility of PPCM properly addressed in the recent statement from the Heart Failure Association of the European Society of Cardiology Working Group on PPCM.3In our article, we discussed a major limitation of our study: that we had not performed cardiological screening of family members of those PPCM patients who had recovered left ventricular function. We emphasized the importance of studying these cases in the future because they also can be part of familial cardiomyopathy. This is corroborated by the case report by Baruteau et al on the occurrence of PPCM in two sisters with full recovery.4 Besides, apparent recovery is not always true recovery, because it has been reported that patients have died during extended follow-up despite recovery of left ventricular function at 6 months' assessment.5 Thus, we fully agree with Baruteau et al that it is justifiable to offer cardiological screening to first-degree relatives of recovered PPCM patients.Karin Y. van Spaendonck-Zwarts, MDJ. Peter van Tintelen, MD, PhDJan D.H. Jongbloed, PhD Department of Genetics University Medical Centre Groningen University of Groningen Groningen, the NetherlandsDirk J. van Veldhuisen, MD, PhDRik van der Werf, MDMaarten P. van den Berg, MD, PhD Department of Cardiology University Medical Centre Groningen University of Groningen Groningen, the NetherlandsWalter J. Paulus, MD, PhD Department of Physiology Free University Medical Centre Amsterdam, the NetherlandsDennis Dooijes, PhD Department of Genetics Erasmus Medical Centre Rotterdam, the NetherlandsDisclosuresNone.