bluuebunny/crossref_metadata_2025 huggingface dataset:
Daily species checklist from whale-watching—studying the research potential with an Azorean case study
Authors: Gomes Pereira José Nuno D.S.
Published: September 2008

The present work uses daily checklist data from whale-watching to study basic aspects of cetacean ecology. Data in the Azores consists of a simple daily list of all species sighted by boats, with no additional information. The Azorean whale-watching activity is described and sources of variation related to data collection are debated. A data-set from one whale-watching company is analysed from 2001 to 2006, from April to October (tourism season). The first four years were used to describe frequencies in the area, and maximum and minimum regional sea surface temperatures for nineteen cetacean species, based on remote sensed data. Several species were present throughout the season, while for others, results indicate transient habits in the study area (Balaenopterids, Globicephala sp., Pseudorca crassidens, Orcinus orca and Hyperodoon ampullatus). Reservations were made relative to small size and evasive species. Sighting frequencies on temperature classes in 2005 and 2006 were used successfully in an experimental approach to study delphinid simpatry. The simplicity of data was overcome by the diversity of sighted species and the dimension of the time scale. Daily checklist is a low cost useful source of information mainly for large cetaceans that should keep being registered.
Redescription of the zooxanthellateEudendrium moulouyensis(Eudendriidae: Hydrozoa) from the Mediterranean Sea
Authors: De Vito D. , Boero F. , Di Camillo C.G. , Megina C. , Piraino S.
Published: September 2008

Eudendrium moulouyensisis a zooxanthellate hydroid originally described from the Chafarinas Islands (Alboran Sea, south-western Mediterranean) in summer 1991. According to the original description, this species can be identified due to the occurrence of symbiotic zooxanthellae in the entire endodermal layer of the colony (gastrodermis and tentacle endodermis), a unique feature among the MediterraneanEudendriumspecies. However, several aspects of its life cycle and the extent of its phenotypical variability are still unknown. Since winter 2004, colonies ofE. moulouyensiswere recorded throughout the year from 0.5 m to 30 m depth from the southern Adriatic Sea (Otranto Channel) and the Gibraltar Strait (Alboran Sea). Additional specimens were collected from the northern Adriatic (Vis, Croatia), Sicily Channel (Pantelleria and Lampedusa Islands), and western Sardinia (Costa Paradiso). These findings offered the opportunity to describe for the first time the full life cycle and to elucidate several biological aspects related to phenotypical variation of colony morphology, vertical zonation, seasonality, zooxanthellae–polyp relationship, and cnidome morphology and distribution. The number and morphology of male gonophores per reproductive polyp is described here for the first time, providing a useful taxonomic character to easily discriminateMyrionema amboinensefromE. moulouyensis. From the available information, the occurrence ofM. amboinensein the Mediterranean Sea should be regarded as doubtful, if they are not accompanied by observations of cnidome, male gonophores or distinctly separate tentacles whorls.
Sympagohydra tuuli gen. nov. and sp. nov. (Cnidaria: Hydrozoa) a cool hydroid from the Arctic sea ice
Authors: Piraino S. , Bluhm B.A. , Gradinger R. , Boero F.
Published: September 2008

A new interstitial hydroid, Sympagohydra tuuli, has been collected from the three-dimensional brine channel system of the coastal fast ice off Barrow, Alaska (71°N 156ºW) in 2003 to 2006. This is the first cnidarian species described from the sea ice interstitial habitat. A morphological and systematic account of the new species is provided here. The hydroid stage is represented by solitary naked polyps, which become almost spherical under contraction. Body length can vary from 200 µm to >1 mm according to the degree of relaxation. The aboral side is extensible into a tubular foot-like projection made by epidermal tissue only, a typical feature of representatives of Protohydridae, order Capitata. However, in contrast to the other two known Protohydridae species, S. tuuli is characterized by three to four solid filiform tentacles, armed with microbasic mastigophore and desmoneme cnidocysts, and located at the base of a short hypostome bearing stenoteles. A small number of mastigophores are also scattered along the body column. Due to its unique combination of features, this taxon is designated here as a new species, and the new genus Sympagohydra is established as a new member of the class Hydroidomedusa, subclass Anthomedusae, order Capitata, family Protohydridae, to accommodate S. tuuli.
Soil-transmitted helminthiasis among mothers and their pre-school children on Unguja Island, Zanzibar with emphasis upon ascariasis
Authors: STOTHARD J. R. , IMISON E. , FRENCH M. D. , SOUSA-FIGUEIREDO J. C. , KHAMIS I. S. , ROLLINSON D.
Published: September 2008

Soil-transmitted helminthiasis (STH) is a scourge to the health and well-being of infants and pre-schoolchildren throughout many parts of sub-Saharan Africa. To improve maternal and child health, regular de-worming is recommended and often delivered from mother and child health (MCH) clinics, yet there have been few studies monitoring the progress and impact of interventions on local levels of disease. A cross-sectional parasitological survey, supplemented with questionnaires, was therefore conducted across 10 Ungujan villages examining mothers (n=322) and their pre-school children (n=359). Within children, mean prevalence of ascariasis, trichuriasis and hookworm was 8·6% (95% CI 5·5–11·8), 18·9% (95% CI 14·5–23·4) and 1·7% (95% CI 0·2–3·5) while in mothers mean prevalence was 6·7% (95% CI 3·7–9·7), 11·9% (95% CI 8·0–15·8) and 1·9% (95% CI 0·2–3·5), respectively. There was, however, significant spatial heterogeneity of STH by village, 2 villages having much elevated levels of infection, although general access to anthelminthics and utilization of village MCH clinics was good. Levels of parasite aggregation (k) were determined and a multilevel logistic regression model identified access to a household latrine [OR=0·56 (95% CI 0·32–0·99)] and having an infected household member [OR=3·72 (95% CI 2·22–6·26)] as observed risk factors. To further investigate worm burdens of Ascaris lumbricoides, adult worms were expelled using Combantrin® and measured. A negative relationship between mean worm burden and mean worm mass was found. Villages in the north of Unguja represent locations where there is elevated prevalence of both ascariasis and trichuriasis and it appears that local factors are particularly favourable for transmission of these helminths. From a perspective of control, in such locations, intervention efforts should be stepped up and greater efforts placed upon improving household sanitation.
Brain morphometry volume in autistic spectrum disorder: a magnetic resonance imaging study of adults
Authors: Hallahan B. , Daly E. M. , McAlonan G. , Loth E. , Toal F. , O'Brien F. , Robertson D. , Hales S. , Murphy C. , Murphy K. C. , Murphy D. G. M.
Published: September 2008

Background

Several prior reports have found that some young children with autism spectrum disorder [ASD; including autism and Asperger's syndrome and pervasive developmental disorder – not otherwise specified (PDD-NOS)] have a significant increase in head size and brain weight. However, the findings from older children and adults with ASD are inconsistent. This may reflect the relatively small sample sizes that were studied, clinical heterogeneity, or age-related brain differences.

Method

Hence, we measured head size (intracranial volume), and the bulk volume of ventricular and peripheral cerebrospinal fluid (CSF), lobar brain, and cerebellum in 114 people with ASD and 60 controls aged between 18 and 58 years. The ASD sample included 80 people with Asperger's syndrome, 28 with autism and six with PDD-NOS.

Results

There was no significant between-group difference in head and/or lobar brain matter volume. However, compared with controls, each ASD subgroup had a significantly smaller cerebellar volume, and a significantly larger volume of peripheral CSF.

Conclusions

Within ASD adults, the bulk volume of cerebellum is reduced irrespective of diagnostic subcategory. Also the significant increase in peripheral CSF may reflect differences in cortical maturation and/or ageing.
Eighty-five per cent of what? Discrepancies in the weight cut-off for anorexia nervosa substantially affect the prevalence of underweight
Authors: Thomas J. J. , Roberto C. A. , Brownell K. D.
Published: September 2008

Background

DSM-IV cites <85% of expected body weight (EBW) as a guideline for the diagnosis of anorexia nervosa (AN) but does not require a specific method for calculating EBW. The purpose of the present study was to determine the degree to which weight cut-off calculations vary across studies, and to evaluate whether differential cut-offs lead to discrepancies in the prevalence of individuals who are eligible for the AN diagnosis.

Method

Two coders independently recorded the EBW calculation methods from 99 studies that either (a) compared individuals with AN to those with subclinical eating disorders or (b) conducted AN treatment trials. Each weight cut-off was applied to a nationally representative (n=12001) and treatment-seeking (n=189) sample to determine the impact of EBW calculation on the proportion who met the AN weight criterion.

Results

Coders identified 10 different EBW methods, each of which produced different weight cut-offs for the diagnosis of AN. Although only 0.23% of the national sample met the lowest cut-off, this number increased 43-fold to 10.10% under the highest cut-off. Similarly, only 48.1% of treatment seekers met the lowest cut-off, whereas 89.4% met the highest.

Conclusions

There is considerable variance across studies in the determination of the AN weight cut-off. Discrepancies substantially affect the proportion of individuals who are eligible for diagnosis, treatment and insurance reimbursement. However, differences may not be fully appreciated because the ubiquitous citation of the 85% criterion creates a sense of false consensus.
The responsibilities of victory: Jus Post Bellum and the Just War
Authors: BELLAMY ALEX J.
Published: September 2008

Recent years have seen a growing interest in questions about justice after war (jus post bellum), fuelled in large part by moral questions about coalition operations in Afghanistan and Iraq. As a result, it has become common to argue that jus post bellum is a third strand of Just War thinking. This article evaluates this position. It argues that that there are broadly two ways of understanding moral requirements after war: a minimalist position which holds that moral principles derived largely from jus ad bellum and jus in bello concerns should constrain what victors are entitled to do after war and a maximalist position which holds that victors acquire additional responsibilities that are grounded more in liberalism and international law than in Just War thinking. Finding problems with both approaches, the article argues that it is premature to include jus post bellum as a third element of Just War thinking and concludes by setting out six principles to guide future thinking in this area.
Legitimacy and the use of force: bridging the analytical – normative divide
Authors: BJOLA CORNELIU
Published: September 2008

By remaining epistemologically committed to an outdated distinction between facts and values, traditional definitions of legitimacy either divest the concept of an important critical component or fail to properly anchor it in the social reality. As an alternative, the article proposes a constitutive theory of legitimacy that reconciles the epistemological tension via the concepts of fairness and tractability and bridges the theoretical gap via the concept of deliberative legitimacy. By applying it to the issue of the use of force, the article argues that a normatively sound and politically relevant model of legitimacy must take into account both to the manner in which actors’ commitment to social norms is crafted and the type of conditions that facilitate or constrain the definition, contestation, and adjudication of what counts as legitimacy in a particular political context.
Justus Lipsius, political humanism and the disciplining of 17th century statecraft
Authors: LEIRA HALVARD
Published: September 2008

Justus Lipsius (1547–1606) was among the most influential thinkers of the late 16th/early 17th centuries. His guides for action were highly influential in the establishment of moderate absolutism and what has been called the fiscal-military state across Europe. In this article I explore Lipsian thought in an International Relations context. Special attention is paid to his ideals of discipline, which were meant to order both the ruler and those that he ruled. Dignity, self-restraint and discipline were the recipes for the foreign policy of the prince, while the individual was subordinated to the purposes of the state, and taught to control his own life by mastering his emotions. If not a seminal thinker in his own right, it is necessary to understand Lipsius’ thought and influence to be able to fully understand the 17th century theoretical approaches to peace and prosperity and the relative discipline of early-modern statecraft.
Periphery theorising for a truly internationalised discipline: spinning IR theory out of Anatolia
Authors: AYDINLI ERSEL , MATHEWS JULIE
Published: September 2008

Concerns over inequalities that have been located between the roles of the core and periphery within the development of the IR discipline have led to questions of whether it is possible to build up theoretical concepts in IR based on national differences. There have not yet been studies however providing an in-depth look at how IR theorising has been developing within a periphery country or region, and exploring both the local and core level factors inhibiting the development of original theoretical paradigms from within that context. By looking at the Turkish experience, the article postulates that homegrown theorising may be the only means for periphery IR to be respectfully acknowledged by the core IR discipline.
Metacommunity structure of tropical forest along an elevation gradient in Puerto Rico
Authors: Barone John A. , Thomlinson John , Cordero Pedro Anglada , Zimmerman Jess K.
Published: September 2008

The development of metacommunity theory, which suggests that the diversity and composition of communities is influenced by interactions with other communities, has produced new tools for evaluating patterns of community change along environmental gradients. These techniques were used to examine how plant communities changed along elevation gradients in montane tropical forests. Two transects of 0.1-ha vegetation plots were established every 50 m in elevation in the mountains of eastern Puerto Rico. The transects ranged from 300 m to 1000 m asl and 400 m to 900 m. In each plot, all free-standing woody stems greater than 1 cm in diameter at 130 cm in height were marked, measured and identified. Additional data on three similar transects were taken from the literature. The upper or lower boundaries of species ranges were significantly clumped along all five transects. Coherence, a measure of the number of gaps in species distributions, was also significant across all transects, and three transects showed significant, albeit low, nestedness. Four sites had significant species turnover. These results suggest that metacommunity techniques can be useful in searching for patterns of community change present in montane tropical forests.
The pollination ecology of the late-successional tree, Oroxylum indicum (Bignoniaceae) in Thailand
Authors: Srithongchuay Tuanjit , Bumrungsri Sara , Sripao-raya Ekapong
Published: September 2008

Although plant species that attract multiple species of pollinators predominate in tropical plant communities, pollination specialists appear to be at a greater advantage in tropical ecosystems in which pollinators are numerous and many plants flower synchronously. The present study determined the breeding system and legitimate pollinators ofOroxylum indicumVent. in Songkhla and Patthalung Provinces, Thailand.Oroxylum indicumexhibits steady-state flowering, with one or two flowers per inflorescence opening each night. Flowers open in the evening and drop off shortly after midnight, while its bilabiate stigma is highly sensitive, and quickly close upon being touched.Oroxylum indicumis self-incompatible. Hand-cross pollination and open pollination yielded the highest pollination success (47.7% and 31.2% respectively, n = 7 trees). About 900 pollen grains are needed for initiating fruit set. It is confirmed that a fruit bat,Eonycteris spelaea, is the legitimate pollinator. Bats are responsible for all pollen load and the pollen load from only one visit is generally sufficient to initiate fruit set. AlthoughEonycteris spelaeais effective, it is an inefficient pollinator. Compared with plant species pollinated by multiple animal species, the likelihood of pollination failure resulting from the decline in populations ofEonycteris spelaeawill be much more intense inOroxylum indicum.
Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia
Authors: Chen Ya-Jun , Bongers Frans , Cao Kun-Fang , Cai Zhi-quan
Published: September 2008

In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test the effect of light (4% and 35% full sun, using neutral-density screen) on the competitive interactions between seedlings of one liana (Byttneria grandifolia) and three tree species (two shade-tolerant trees,Litsea dilleniifoliaandPometia tomentosa, and one light-demanding tree,Bauhinia variegata) and to evaluate the contribution of both above- and below-ground competition. Trees were grown in four competition treatments with the liana: no competition, root competition, shoot competition and root and shoot competition. Light strongly affected leaf photosynthetic capacity (light-saturated photosynthetic rate,Pn), growth and most morphological traits of the tree species. Liana-induced competition resulted in reducedPn, total leaf areas and relative growth rates (RGR) of the three tree species. The relative importance of above- and below-ground competition differed between the two light levels. In low light, RGR of the three tree species was reduced more strongly by shoot competition (23.1–28.7% reduction) than by root competition (5.3–26.4%). In high light, in contrast, root competition rather than shoot competition greatly reduced RGR. Liana competition affected most morphological traits (except for specific leaf area and leaf area ratio ofLitseaandPometia), and differentially altered patterns of biomass allocation in the tree seedlings. These findings suggest that competition from liana seedlings can greatly suppress growth in tree seedlings of both light-demanding and shade-tolerant species and those effects differ with competition type (below- and above-ground) and with irradiance.
Introduction: Towards a Genetic Study of Performance – Take 2
Authors: FÉRAL JOSETTE
Published: September 2008

Analysing a performance from the viewpoint of what is presented to the public always overlooks the creative work which led to it, the preliminary work which leads up to the performance in question and is made up of explorations, trials and errors, forward and backward moves during which the basis for the final performance is laid down. These moments are witness to the life animating a performance's preparation and explain its development. This means that to study any representation of a performance with a view to analysing it will always remain a single moment in a process which constantly needs to be reaffirmed. This ‘genealogical’ work of preparation; the phases of the staging's constructive work; the research carried out by the actor on his or her text; and the hesitancies, erasures, choices and discoveries generated by a collective work are fundamental to comprehending the representation. They bring its meaning to light and allow us to observe creation at work: creation of the stage setting, of a part, of a character and so on. This procedure is not only indispensable for a better understanding of the performance under study, but also affords a better comprehension of the phases of the creative act itself. Therefore the following essay, an introduction to those that follow, attempts to lay down the basis for defining what should be the tools and corpus for such a field of study.
Written Documents of the Assistant Director: A Record of Remaking
Authors: PROUST SOPHIE
Published: September 2008

The aim of this article is to establish a classification for the various written documents produced by assistant directors (before and during the rehearsals, during the run-throughs, from the first performance onwards and so on). It also underlines theatrical work as an autonomous subject of interest. These written documents are useful, and even indispensable according to certain directors. The notes may differ in nature at different times in the production process. In their finality they preserve a record of what is to be redone, a record of the work whose existence the audience does not suspect. Contrary to what one might believe, it is not always the actors who retain the truest memory of their work. The following is based partly on my own experience as assistant director, or intern, to Yves Beaunesne, Denis Marleau, Matthias Langhoff and Robert Wilson.
Art in Dispute at the Beaverbrook Art Gallery
Authors: Cushing Deborah
Published: September 2008

A long-running dispute between the Beaverbrook Art Gallery and its benefactor foundations illustrates the need for documentation of gifts or loans of artwork. At issue in this dispute is ownership of over 200 of the paintings on display at the gallery valued at up to $200 million. None of the parties to the dispute has been able to produce records to establish that the paintings were either a gift or on loan to the Beaverbrook. Instead the parties have had to rely on newspaper and magazine articles, speeches, gallery catalogues, and export documents to substantiate their positions. Central to the dispute has been the role of the First Lord Beaverbrook and whether his actions amounted to a breach of his fiduciary duty to the gallery. This article examines the particulars of the parties' claims as well as the decisions that have been made to date. Final resolution of the dispute is not expected until all appeals have been decided.
A Māori Head: Public Domain?
Authors: Amiel Olivier
Published: September 2008

This case arose out of a controversy over the return of a Māori head from the collection of a city of Rouen museum to New Zealand. The case raised the issue of whether the head was a French public good that required declassification before it could be returned or a body part (and not a work of art) that could be immediately returned for appropriate treatment in its place of origin.
A Coordinated Legal and Policy Approach to Undiscovered Antiquities: Adapting the Cultural Heritage Policy of England and Wales to Other Nations of Origin
Authors: Fincham Derek
Published: September 2008

Blanket ownership laws, export restrictions, and the criminal law of market nations are the default legal strategies currently used by nations of origin to prevent the looting of archaeological sites. Although they have been remarkably successful at achieving the return of looted objects, they may not be the best strategies to maximize the recording and preservation of archaeological context. In England and Wales a more permissive legal regime broadly applied and adopted by the public at large has produced dramatically better results than the strong prescriptive regime of Scotland, which can be easily ignored.

This article attempts to clear up any misconceptions of the cultural policy framework in England and Wales. It accounts for the legal position accorded undiscovered portable antiquities, and describes how this legal framework is perfected by a voluntary program called the Portable Antiquities Scheme (PAS). This approach stands in stark contrast to Scotland, which has used a legal strategy adopted by most other nations of origin.

The domestic legal framework for portable antiquities in England and Wales is unique and differs from the typical approach. Coupled with the PAS, this legal structure has resulted in a better cultural policy, which leads to less looting of important archaeological sites, allows for a tailored cultural policy, and has produced more data and contextual information with which to conduct historical and archaeological research on an unprecedented scale. Compensating finders of antiquities may even preclude an illicit market in antiquities so long as this compensation is substantially similar to the market price of the object and effectively excludes looters from this reward system. Although the precise number of found versus looted objects that appear on the market is open to much speculation, an effective recording system is essential to ensure that individuals who find objects are encouraged to report them.
EDITORIAL
Authors: BUTT JOHN
Published: September 2008

I clearly remember that when this journal was first devised there lay some niggling doubt behind my tremendous enthusiasm for this timely initiative. Wasn’t there something problematic about viewing the eighteenth century as a whole? Did I intuit some sort of fundamental divide, perhaps somewhere between the deaths of J. S. Bach and Handel, one that somehow cast this century into two irreconcilable worlds? The seventeenth century was perhaps enough of a mess for its disunity to become a historiographical topic in its own right, its separate threads providing at least some narrative potential, even if these could never convincingly be drawn into a single whole. And the nineteenth century was perhaps sufficiently punctuated with various revolutions and restorations, together with an overriding story of industrial progress, to fall into a coherent (if divisive) family of narratives. Even the twentieth century – that which surely saw the largest number of changes in the human condition and the exponential pluralizing of ‘legitimate’ musical traditions – seems to have a clear enough trajectory, much of the music at its end having a discernible genealogical connection with that of its beginning. So what was it that was worrying me about the eighteenth century?
Electron density and electron neutral collision frequency in the ionosphere using plasma impedance probe measurements
Authors: Spencer E. , Patra S. , Andriyas T. , Swenson C. , Ward J. , Barjatya A.
Published: September 2008

Swept Impedance Probe measurements in a sporadic E layer observed during the Sudden Atomic Layer (SAL) sounding rocket mission are analyzed to obtain absolute electron densities and electron neutral collision frequencies accurately. Three sets of upleg and downleg impedance data are selected for the analysis. Initial estimates of the plasma parameters are obtained through a least mean square fit of the measured impedance data against the analytical impedance formula ZB(f) of Balmain (1969). These initial parameters are used as a starting point to drive a finite difference computational model of an antenna immersed in a plasma called PF‐FDTD. The parameters are then tuned until a close fit is obtained between the measured impedance data and the numerical impedance data calculated by the PF‐FDTD simulation. The electron densities obtained from the simulation were close to those obtained from the IRI 2001 model. The electron neutral collision frequencies obtained from the more accurate PF‐FDTD simulation were up to 20% lower than the values predicted by Balmain's formula. The obtained collision frequencies are also lower than the quiet time values predicted by Schunk and Nagy (2000) when used in conjunction with neutral densities and electron temperature from the Mass Spectrometer Incoherent Scatter Radar Extended‐90 model.
Micromechanical modeling of the viscoplastic behavior of olivine
Authors: Castelnau O. , Blackman D. K. , Lebensohn R. A. , Ponte Castañeda P.
Published: September 2008

Efforts to couple mantle flow models with rheological theories of mineral deformation typically ignore the effect of texture development on flow evolution. The fact that there are only three easy slip systems for dislocation glide in olivine crystals leads to strong mechanical interactions between the grains as the deformation proceeds, and subsequent development of large viscoplastic anisotropy in polycrystals exhibiting pronounced Lattice Preferred Orientations. Using full‐field simulations for creep in dry polycrystalline olivine at high temperature and low pressure, it is shown that very large stress and strain rate intragranular heterogeneities can build up with deformation, which increase dramatically with the strength of the hard slip system (included for the purpose of enabling general deformations). Compared with earlier nonlinear extensions of the Self‐Consistent mean‐field theory to simulate polycrystal deformation, the “Second‐Order” method is the only one capable of accurately describing the effect of intraphase stress heterogeneities on the macroscopic flow stress, as well as on the local stress‐ and strain rate fluctuations in the material. In particular, this approach correctly predicts that olivine polycrystals can deform with only four independent slip systems. The resistance of the fourth system (or accommodation mechanism), which is likely provided by dislocation climb or grain boundary processes as has been observed experimentally, may essentially determine the flow stress of olivine polycrystals. We further show that the “tangent” model, which had been used extensively in prior geophysical studies of the mantle, departs significantly from the full‐field reference solutions.
An elastic plate model for wave attenuation and ice floe breaking in the marginal ice zone
Authors: Kohout A. L. , Meylan M. H.
Published: September 2008

We present a model for wave attenuation in the marginal ice zone (MIZ) based on a two‐dimensional (one horizontal and one vertical dimension) multiple floating elastic plate solution in the frequency domain, which is solved exactly using a matched eigenfunction expansion. The only physical parameters that enter the model are length, mass, and elastic stiffness (of which, the latter two depend primarily on thickness) of the ice floes. The model neglects all nonlinear effects as well as floe collisions or ice creep and is therefore most applicable to floes which are large compared to the thickness and to wave conditions which are not extreme. The solution for a given arrangement of floes is fully coherent, and the results are therefore dependent on the exact geometry. We firstly show that this dependence can be removed by averaging over a distribution of floe lengths (we choose the Rayleigh distribution). We then show that after this averaging, the attenuation coefficient is a function of floe number and independent of floe length, provided the floe lengths are sufficiently large. The model predicts an exponential decay of energy, just as is shown experimentally. This enables us to provide explicit values for the attenuation coefficient, as a function of the average floe thickness and wave period. We compare our theoretical predictions of the wave attenuation with measured data and other scattering models. The limited data allows us to conclude that our model is applicable to large floes for short to medium wave periods (6 to 15 seconds). We also derive a floe breaking model, based on our wave attenuation model, which indicates that we are under‐predicting the attenuation coefficients at long periods.
Low‐ozone pockets observed by EOS‐MLS
Authors: Harvey V. Lynn , Randall Cora E. , Manney Gloria L. , Singleton Cynthia S.
Published: September 2008

Earth Observing System (EOS) Microwave Limb Sounder (MLS) observations of ozone are analyzed along with meteorological data from the Met Office using a new automated algorithm to detect low‐ozone pockets (LOPs) in stratospheric anticyclones. The algorithm is illustrated with a case study, and all LOPs identified in over 3 years of MLS data are shown. Daily averaged LOP ozone mixing ratios are 5–30% lower than ozone mixing ratios located directly outside a LOP. In the middle stratosphere, near 50° latitude and the Date Line, large LOPs are identified on over 60% of Northern Hemisphere (NH) winter and 50% of Southern Hemisphere (SH) spring days. This suggests that a LOP is present in the Aleutian and Australian anticyclones nearly all the time during these seasons. Ozone reductions in the heart of the LOPs are typically about 20% (10%) in the NH (SH). Thus the LOP contribution to seasonal ozone loss in the anticyclones is estimated at up to ∼12% in NH winter and ∼5% in SH spring. Average total column ozone loss from individual LOPs is estimated at ∼3–6%.
Seasonal CO2 rectifier effect and large‐scale extratropical atmospheric transport
Authors: Chan Douglas , Ishizawa Misa , Higuchi Kaz , Maksyutov Shamil , Chen Jing
Published: September 2008

In atmospheric transport models, the covariation of the atmospheric transport and annually neutral biospheric CO2 flux is usually evident as the annual zonal mean surface CO2 concentration gradient. Using the NIES transport model and CO2 flux from the Biome‐BGC model, the covariations of different transport mechanisms and CO2 flux were examined and quantified. Including the covariation of the total transport (processes included in the NIES model) and CO2 flux, the annual average pole to pole CO2 concentration gradient is 3.5 ppm and interhemispheric difference of the average extratropical surface concentration is 2.5 ppm. The conventional covariation mechanism of the seasonal variation of planetary boundary layer mixing height and CO2 flux accounts for approximately 45% of the CO2 concentration gradient. Another important contribution to the CO2 concentration gradient in this model is the covariation of the extratropical anomaly transport (mainly by cyclones and anticyclones) and the biospheric flux, which accounts for about 55%. This alternate physical mechanism is the association of stronger meridional (north–south) anomaly transport (under strong baroclinic instability condition) with higher CO2 concentration from soil respiration in the winter and weaker anomaly transport (weak baroclinic instability condition) with lower CO2 concentration from photosynthetic uptake in the summer. The net result of the meridional transport and flux covariation is a north–south annual zonal mean CO2 concentration gradient.
Seasonal variation of nitrogen oxides in the central North Atlantic lower free troposphere
Authors: Val Martin M. , Honrath R. E. , Owen R. C. , Li Q. B.
Published: September 2008

Measurements of NO, NO2, and NOy (total reactive nitrogen oxides) made at the Pico Mountain station, 38.47°N, 28.40°W, 2.2 km above sea level, from July 2002 to August 2005 are used to characterize the seasonal and diurnal variations of nitrogen oxides in the background lower free troposphere (FT) over the central North Atlantic Ocean. These observations reveal a well‐defined seasonal cycle of nitrogen oxides (NOx = NO + NO2 and NOy), with higher mixing ratios during the summertime. Observed NOx and NOy levels are consistent with long‐range transport of emissions, with significant removal en route to the measurement site. Larger summertime nitrogen oxides levels are attributed to boreal wildfire emissions and more efficient export and transport of NOy from eastern North America during that season. In addition, measurements of NOx and NOy obtained during in‐cloud and cloud‐free conditions are used to estimate PAN and HNO3 mixing ratios and examine the partitioning of the reactive nitrogen species. These estimates indicate that reactive nitrogen over the central North Atlantic lower FT largely exists in the form of PAN and HNO3 (∼80–90% of NOy) year‐round. The composition of NOy shifts from dominance of PAN in winter‐spring to dominance of HNO3 in summer‐fall, as a result of changes in temperature and photochemistry over the region. A further comparison of the nitrogen oxides measurements with results from the global chemical transport model GEOS‐Chem finds that simulated nitrogen oxides are significantly larger than the observations.
Large‐scale impacts of anthropogenic pollution and boreal wildfires on the nitrogen oxides over the central North Atlantic region
Authors: Val Martin M. , Honrath R. E. , Owen R. C. , Lapina K.
Published: September 2008

Transport of North American anthropogenic and boreal wildfire emissions is a large source of nitrogen oxides over the North Atlantic region. To characterize the influence of transport of these emissions on nitrogen oxides levels over the central North Atlantic lower free troposphere (FT) and their further implications for hemispheric O3, we analyze measurements of NOx (NO + NO2), total reactive nitrogen oxides (NOy), CO, and O3 made at the Pico Mountain station (38.47°N 28.40°W, 2.2 km above sea level) in the Azores archipelago from July 2002 to August 2005. Transport of pollution from North America causes significant enhancements of nitrogen oxides year‐round. An analysis of the export of United States NOx emissions to the FT based on observed ΔNOy/ΔCO in the anthropogenic plumes indicates that more than 94% of the NOx emitted over the United States is lost within the continent and/or during export out of the United States boundary layer and to the Azores, consistent with previous studies. However, our observations indicate that about 30% of the NOy initially exported out of the United States boundary layer reach the Azores lower FT. NOx was also significantly enhanced in these plumes. Since the lifetime of NOx is shorter than the transport timescale of most events, PAN decomposition and potentially photolysis of HNO3 provide a supply of NOx over the central North Atlantic lower FT. Observed ΔO3/ΔNOy ratios and significant NOy levels remaining in the North American plumes suggest a potential for O3 formation well downwind from North America. Summertime boreal wildfires in North America are responsible for important shifts in the nitrogen oxides distributions toward higher levels, with medians of NOy (117–175 pptv) and NOx (9–30 pptv) greater in boreal wildfire plumes. These findings demonstrate the potential hemispheric scale impact that boreal wildfire and North American anthropogenic events have on background NOx and NOy levels and on the tropospheric O3 budget.
Evaluation of satellite estimates of downward shortwave radiation over the Tibetan Plateau
Authors: Yang Kun , Pinker Rachel T. , Ma Yaoming , Koike Toshio , Wonsick Margaret M. , Cox Stephen J. , Zhang Yuanchong , Stackhouse Paul
Published: September 2008

The state‐of‐the‐art satellite products of downward shortwave radiation over the Tibetan Plateau against ground observations are evaluated in this study. The satellite products include the International Satellite Cloud Climatology Project‐Flux Data (ISCCP‐FD) as produced at the NASA Goddard Institute for Space Studies (GISS) from the ISCCP D1 data, the Global Energy and Water Cycle Experiment‐Surface Radiation Budget (GEWEX‐SRB) results as derived at the NASA Langley Research Center (LaRC) from the ISCCP DX data, and a University of Maryland product derived with a modified version of the University of Maryland Surface Radiation Budget (UMD‐SRB) model as implemented with METEOSAT‐5 observations. These products are at different spatial and temporal resolutions, and the evaluation is performed at their native resolutions. Comparisons indicate that, in this region of great variation in elevation, using hourly, spatially homogeneous, and high resolution satellite data (UMD‐SRB) compares more favorably with surface measurements than products that use three hourly, sparse subsamples at coarse resolutions (ISCCP‐FD and GEWEX‐SRB). Discrepancies among the satellite products are usually larger in highly variable terrain (such as in the Himalayas region) and smaller for nonvariable terrain (such as in the central Plateau). This suggests that errors of satellite products are spatially dependent over the Tibet. Therefore caution needs to be exercised when extending comparison results based on limited in situ data from accessible sites to the entire Plateau. Attention should be also given to the quality of input parameters besides cloud properties, as there are large discrepancies among the satellite products for clear‐sky radiation.
Role of convection in redistributing formaldehyde to the upper troposphere over North America and the North Atlantic during the summer 2004 INTEX campaign
Authors: Fried Alan , Olson Jennifer R. , Walega James G. , Crawford Jim H. , Chen Gao , Weibring Petter , Richter Dirk , Roller Chad , Tittel Frank , Porter Michael , Fuelberg Henry , Halland Jeremy , Bertram Timothy H. , Cohen Ronald C. , Pickering Kenneth , Heikes Brian G. , Snow Julie A. , Shen Haiwei , O'Sullivan Daniel W. , Brune William H. , Ren Xinrong , Blake Donald R. , Blake Nicola , Sachse Glen , Diskin Glenn S. , Podolske James , Vay Stephanie A. , Shetter Richard E. , Hall Samuel R. , Anderson Bruce E. , Thornhill Lee , Clarke Antony D. , McNaughton Cameron S. , Singh Hanwant B. , Avery Melody A. , Huey Gregory , Kim Saewung , Millet Dylan B.
Published: September 2008

Measurements of formaldehyde (CH2O) from a tunable diode laser absorption spectrometer (TDLAS) were acquired onboard the NASA DC‐8 aircraft during the summer 2004 INTEX‐NA campaign to test our understanding of convection and CH2O production mechanisms in the upper troposphere (UT, 6–12 km) over continental North America and the North Atlantic Ocean. The present study utilizes these TDLAS measurements and results from a box model to (1) establish sets of conditions by which to distinguish “background” UT CH2O levels from those perturbed by convection and other causes; (2) quantify the CH2O precursor budgets for both air mass types; (3) quantify the fraction of time that the UT CH2O measurements over North America and North Atlantic are perturbed during the summer of 2004; (4) provide estimates for the fraction of time that such perturbed CH2O levels are caused by direct convection of boundary layer CH2O and/or convection of CH2O precursors; (5) assess the ability of box models to reproduce the CH2O measurements; and (6) examine CH2O and HO2 relationships in the presence of enhanced NO. Multiple tracers were used to arrive at a set of UT CH2O background and perturbed air mass periods, and 46% of the TDLAS measurements fell within the latter category. In general, production of CH2O from CH4 was found to be the dominant source term, even in perturbed air masses. This was followed by production from methyl hydroperoxide, methanol, PAN‐type compounds, and ketones, in descending order of their contribution. At least 70% to 73% of the elevated UT observations were caused by enhanced production from CH2O precursors rather than direct transport of CH2O from the boundary layer. In the presence of elevated NO, there was a definite trend in the CH2O measurement–model discrepancy, and this was highly correlated with HO2 measurement–model discrepancies in the UT.
Combined Simple Biosphere/Carnegie‐Ames‐Stanford Approach terrestrial carbon cycle model
Authors: Schaefer Kevin , Collatz G. James , Tans Pieter , Denning A. Scott , Baker Ian , Berry Joe , Prihodko Lara , Suits Neil , Philpott Andrew
Published: September 2008

Biogeochemical models must include a broad variety of biological and physical processes to test our understanding of the terrestrial carbon cycle and to predict ecosystem biomass and carbon fluxes. We combine the photosynthesis and biophysical calculations in the Simple Biosphere model, Version 2.5 (SiB2.5) with the biogeochemistry from the Carnegie‐Ames‐Stanford Approach (CASA) model to create SiBCASA, a hybrid capable of estimating terrestrial carbon fluxes and biomass from diurnal to decadal timescales. We add dynamic allocation of Gross Primary Productivity to the growth and maintenance of leaves, roots, and wood and explicit calculation of autotrophic respiration. We prescribe leaf biomass using Leaf Area Index (LAI) derived from remotely sensed Normalized Difference Vegetation Index. Simulated carbon fluxes and biomass are consistent with observations at selected eddy covariance flux towers in the AmeriFlux network. Major sources of error include the steady state assumption for initial pool sizes, the input weather data, and biases in the LAI.
Twenty years apart: Comparisons of DOM uptake during leaf leachate releases to Hubbard Brook Valley streams in 1979 versus 2000
Authors: Bernhardt E. S. , McDowell W. H.
Published: September 2008

In seven experiments conducted in late summer 1979 and 2000 extracts of autumn‐shed sugar maple leaves and spruce needles were added to two stream reaches of the Hubbard Brook Experimental Forest at concentrations similar to those found during peak leaf fall. Uptake rates for dissolved organic carbon (DOC) ranged from 7 to 408 mg m−2 h−1. In Bear Brook uptake rates for spruce leachate were lower than for sugar maple leachate in both 1979 and 2000. Uptake velocities tended to be higher for more bioavailable DOC fractions: in 1979, monomeric carbohydrates in DOM were removed from the water column more rapidly than the bulk DOC pool in 4 of 4 cases; in 2000, uptake velocities for N‐containing DOC (DON) were higher than those measured for bulk DOC in 2 of 3 cases. Both results suggest that biological assimilation is an important component of DOM uptake, in contrast to earlier reports that DOM uptake in HBEF streams was primarily through abiotic sorption. In both years, uptake velocities for the same forms of DOM were lower in the high DOC stream Cascade Brook than for the low DOC stream Bear Brook. Experiments in 1979 found no change in inorganic nitrogen concentrations during leachate additions, while all leachate releases in 2000 led to reductions in stream NO3− concentrations.
Laplace equation and Faraday's lines of force
Authors: Narasimhan T. N.
Published: September 2008

Boundary‐value problems involve two dependent variables: a potential function and a stream function. They can be approached in two mutually independent ways. The first, introduced by Laplace, involves spatial gradients at a point. Inspired by Faraday, Maxwell introduced the other, visualizing the flow domain as a collection of flow tubes and isopotential surfaces. Boundary‐value problems intrinsically entail coupled treatment (or, equivalently, optimization) of potential and stream functions. Historically, potential theory avoided the cumbersome optimization task through ingenious techniques such as conformal mapping and Green's functions. Laplace's point‐based approach and Maxwell's global approach each provides its own unique insights into boundary‐value problems. Commonly, Laplace's equation is solved either algebraically or with approximate numerical methods. Maxwell's geometry‐based approach opens up novel possibilities of direct optimization, providing an independent logical basis for numerical models, rather than treating them as approximate solvers of the differential equation. Whereas points, gradients, and Darcy's law are central to posing problems on the basis of Laplace's approach, flow tubes, potential differences, and the mathematical form of Ohm's law are central to posing them in natural coordinates oriented along flow paths. Besides being of philosophical interest, optimization algorithms can provide advantages that complement the power of classical numerical models. In the spirit of Maxwell, who eloquently spoke for a balance between abstract mathematical symbolism and observable attributes of concrete objects, this paper is an examination of the central ideas of the two approaches, and a reflection on how Maxwell's integral visualization may be practically put to use in a world of digital computers.