bluuebunny/crossref_metadata_2025 huggingface dataset:
Rumination, distraction and mindful self-focus: effects on mood, dysfunctional attitudes and cortisol stress response
Authors: Kuehner C. , Huffziger S. , Liebsch K.
Published: May 2008

Background

Although aggravating effects of rumination on dysfunctional cognitions and endocrine stress responses have been proposed, experimental studies testing these assumptions are lacking. In parallel, mindfulness theory suggests beneficial effects of mindfulness on dysfunctional cognitions. This study aimed to investigate the effects of induced rumination, distraction and mindful self-focus on mood and dysfunctional attitudes and to assess the possible impact of induced rumination on participants' cortisol responses.

Method

Sixty university students were subjected to negative mood induction and subsequently randomly assigned to a rumination, distraction or mindful self-focus condition. The latter included statements focusing on self-acceptance and awareness of the breath. Four saliva cortisol samples were selected during the session.

Results

Compared to induced rumination, distraction showed a clear beneficial effect on the course of dysphoric mood, whereas a mindful self-focus did not. In contrast to distraction and mindful self-focus, participants induced to ruminate showed significant increases in dysfunctional attitudes from baseline to post-induction. Although rumination was not itself linked to higher cortisol responses, participants scoring high on the Beck Depression Inventory (BDI)-II who were induced to ruminate showed a smaller decrease in cortisol levels than those scoring low on the BDI-II.

Conclusions

This study indicates that rumination as a dysfunctional mode of cognitive processing is able to maintain depression-linked dysfunctional thought content. Furthermore, our study revealed preliminary indications for a link between induced rumination and the cortisol stress response in vulnerable individuals.
Deformations of asymptotically cylindricalG2-manifolds
Authors: NORDSTRÖM JOHANNES
Published: May 2008

We prove that for a 7-dimensional manifoldMwith cylindrical ends the moduli space of exponentially asymptotically cylindrical torsion-freeG2-structures is a smooth manifold (if non-empty), and study some of its local properties. We also show that the holonomy of the induced metric of an exponentially asymptotically cylindricalG2-manifold is exactlyG2if and only if the fundamental group π1(M) is finite and neitherMnor any double cover ofMis homeomorphic to a cylinder.
The classification of reversible-equivariant steady-state bifurcations on self-dual spaces
Authors: BAPTISTELLI P. H. , MANOEL M.
Published: May 2008

In this paper we apply singularity theory methods to the classification of reversible-equivariant steady-state bifurcations depending on one real parameter. We assume that the group of symmetries and reversing symmetries is a compact Lie group Γ, and the equivalence is defined in order to preserve these symmetries and reversing symmetries in the normal forms and their unfoldings. When the representation of Γ is self-dual, we show that the classification can be reduced to the standard equivariant context. In this case, we establish a one-to-one association between the classification of bifurcations in the reversible-equivariant context and the classification of purely equivariant bifurcations related to them. As an application of the results, we obtain the classification of self-dual representations ofZ2⊕Z2andD4on the plane.
Platforms and Partners: The Civil Rights Realignment Reconsidered
Authors: Feinstein Brian D. , Schickler Eric
Published: May 2008

Few transformations have been more significant in American politics in recent decades than the Democratic Party's embrace of racial liberalism and Republicans' adoption of a more conservative stance towards civil rights-related policies. We hypothesize that pressure to embrace a liberal position on civil rights was much stronger among northern Democrats and their coalitional partners than among northern Republicans and their affiliated groups by the mid-1940s, as the Democrats became firmly identified as the party of economic liberalism and labor unions. To test this hypothesis and develop a more fine-grained understanding of the dynamics of party positioning on civil rights, we collect and analyze a new data source: state political party platforms published between 1920 and 1968. These unique data suggest that Democrats had generally become the more liberal party on civil rights by the mid-to-late 1940s across a wide range of states. Our findings – which contradict Carmines and Stimson's prevailing issue evolution model of partisan change – suggest that there were strong coalitional and ideological pressures that led the Democrats to embrace racial liberalism. This finding not only leads to a revised perspective on the civil rights revolution, but also to new insights into the dynamics of partisan realignment more generally.
Legislative Shirking in the Pre-Twentieth Amendment Era: Presidential Influence, Party Power, and Lame-Duck Sessions of Congress, 1877–1933
Authors: Jenkins Jeffery A. , Nokken Timothy P.
Published: May 2008

In 1933, the Twentieth Amendment to the Constitution was adopted. Otherwise known as the Lame Duck Amendment, it reorganized the congressional terms of office and dates of annual convening, eliminating the short (or “lame-duck”) session that had existed up to that time. The amendment was the brainchild of Sen. George W. Norris (R-NE), who argued that lame-duck sessions posed a grave threat to democratic accountability and responsiveness, as they convenedafterthe elections to thenextCongress and thus were populated in part by members who were retiring or had lost their reelection bids. As a result, according to Norris, the potential for an agency problem in representation was great in lame-duck sessions. Using the literature on legislative shirking—especially the subliterature on last-term effects—as our theoretical backdrop, we investigate Norris's arguments in detail, examining whether his concerns regarding lame-duck sessions were justified. Using a variety of data and a number of tests, we find little systematic evidence to suggest that exiting members altered their behavior significantly (i.e., shirked) in their last terms in office. In short, the concerns that Norris expressed, such as excessive presidential influence in the legislative process and increased majority-party manipulation of the legislative agenda, were not in fact major problems in lame-duck sessions.
Managing the Periphery in the Gilded Age: Writing Constitutions for the Western States
Authors: Bridges Amy
Published: May 2008

In this essay I argue that in the Gilded Age (the last quarter of the nineteenth century), delegates to constitutional conventions in the western territories designed state governments to manage, as best they could, the development of their economies. They were, and understood themselves to be, citizens of the periphery of the United States. Delegates to the conventions hoped to shield their states from the worst possible outcomes of that peripheral relationship, and foster the best ones. My arguments contribute to our understanding of state constitutions and, more broadly, to central concerns of American political development—regionalism, labor law, and state building.
Racial Reorganization and the United States Census 1850–1930: Mulattoes, Half-Breeds, Mixed Parentage, Hindoos, and the Mexican Race
Authors: Hochschild Jennifer L. , Powell Brenna Marea
Published: May 2008

Between 1850 and 1930, demographic upheaval in the United States was connected to reorganization of the racial order. Socially and politically recognized boundaries between groups shifted, new groups emerged, others disappeared, and notions of who belonged in which category changed. All recognized racial groups—blacks, whites, Indians, Asians, Mexicans and others—were affected. This article investigates how and why census racial classification policies changed during this period, only to stabilize abruptly before World War II. In the context of demographic transformations and their political consequences, we find that census policy in any given year was driven by a combination of scientific, political, and ideological motivations.

Based on this analysis, we rethink existing theoretical approaches to censuses and racial classification, arguing that a nation's census is deeply implicated in and helps to construct its social and political order. Censuses provide the concepts, taxonomy, and substantive information by which a nation understands its component parts as well as the contours of the whole; censuses both create the image and provide the mirror of that image for a nation's self-reflection. We conclude by outlining the meaning of this period in American history for current and future debates over race and classification.
A benthic richness hotspot in the Southern Ocean: slope and shelf cryptic benthos of Shag Rocks
Authors: Barnes David K.A.
Published: May 2008

Shelf and slope cryptofauna were sampled at the most northerly shelf environments within the Southern Ocean, Shag Rocks. The area is remarkably rich, with seven phyla, 10 classes, 40 families and 81 species on 0.36 m2of shelf boulders. A large proportion of genera and species found had not been seen there before, some were new to science and species accumulation curves did not approach an asymptote. Current estimates of benthic diversity are clearly still too low if even well studied locations and depths reveal so much novelty with such little sample effort. Proportions of new species were higher in slope samples showing how little we know of this important depth. Significantly, life was just as rich and, surprisingly, abundant on boulders from continental slope depths. Clearly there are places where the continental slope around Antarctica harbours a wealth of species with potential to resupply the shelf if life was ‘bulldozed’ off it by past ice shelf expansions during glacial maxima. Some species on boulders from 1500 m also occur as shallow as the Antarctic intertidal zone. That this rich fauna was ‘Antarctic’ in character shows the extremes, e.g. sea temperature (> 4°C in summer), that they can adapt to given long enough time periods.
Marine richness and gradients at Deception Island, Antarctica
Authors: Barnes David K.A. , Linse Katrin , Enderlein Peter , Smale Dan , Fraser Keiron P.P. , Brown Matt
Published: May 2008

Studies of the recovery of the fauna following the 1967–70 eruptions at Deception Island, South Shetland Islands, have made it one of the best-studied marine sites of the Southern Ocean for biodiversity. Using SCUBA we surveyed the mega- and macro-epifauna of its subtidal zones in the entrance (Neptune's Bellows), immediately inside the caldera (Whaler's Bay) and well within the caldera (Fumarole Bay). Richness declined from 10 phyla, 13 classes and 35 species at Neptune's Bellows to three phyla, four classes and five species in Whaler's Bay and just two phyla, classes and species at Fumarole Bay. Amongst the 35 species we found at Neptune's Bellows, 14 were previously unrecorded from Deception Island. Despite many ship visits and amongst the warmest sea temperatures in the Southern Ocean, the Non Indigenous Species (NIS) algae were not found in our survey. Deception Island has been recolonized considerably since the recent eruptions, but many taxa are still very poorly represented and the colonizers present are mainly those with planktotrophic larvae. Examination of the literature revealed that to date 163 named marine species have been found within the caldera as well as at least 50 more morphospecies, which are yet to be identified. Species accumulation has consistently increased across eight recent samples reported and the number of species reported there is likely to reach 300 when taxa such as the nematodes are identified to species level. This represents a first meaningful total species estimate for an Antarctic marine area and, as the site is comparatively impoverished, indicates how rich the surrounding Antarctic shelf must be.
Epibenthic macrofauna associated with the shelf and slope of a young and isolated Southern Ocean island
Authors: Kaiser Stefanie , Barnes David K.A. , Linse Katrin , Brandt Angelika
Published: May 2008

The remote South Sandwich arc is an archipelago of small volcanic islands and seamounts entirely surrounded by deep water and about 600 km away from the closest island, South Georgia. As some of the youngest islands (< 5 m.y.) in the Southern Ocean they are ideal for studying colonization processes of the seabed by benthic fauna, but are rarely investigated because of remoteness and extreme weather. The current study attempted to quantify the richness and abundance of the epibenthic macrofauna around the Southern Thule group by taking five epibenthic sledge samples along a depth transect including three shelf (one at 300 m and two at 500 m) and two slope stations (1000 and 1500 m). Our aim was to investigate higher taxon richness and community composition in an isolated Antarctic locality, since recent volcanic eruptions between 1964 and 1997. We examined patterns across all epibenthic macrofauna at phylum and class levels, and investigated trends in some model groups of crustaceans to order and family level. We found that abundance was highest in the shallowest sample and decreased with depth. Shelf samples (300 and 500 m) were dominated by molluscs and malacostracans while at the deeper stations (1000 and 1500 m) nematodes were the most abundant taxon. Surprisingly, the shallow shelf was dominated by animals with restricted dispersal abilities, such as direct developing brooders (malacostracans) or those with lecithotrophic larvae (bivalves of the genusYoldiella, most bryozoan species). Despite Southern Thule's geological youth, recent eruptions, and its remoteness the shallow shelf was rich in higher taxa (phyla/classes) as well as orders and families of our model groups. Future work at higher taxonomic resolution (species level) should greatly increase understanding of how life has reached and established on these young and highly disturbed seabeds.
DNA barcodes of fish of the Scotia Sea, Antarctica indicate priority groups for taxonomic and systematics focus
Authors: Rock J. , Costa F.O. , Walker D.I. , North A.W. , Hutchinson W.F. , Carvalho G.R.
Published: May 2008

We analysed cytochrome oxidase I (COI) barcodes for 35 putative fish species collected in the Scotia Sea, and compared the resultant molecular data with field-based morphological identifications, and additional sequence data obtained from GenBank and the Barcode of Life Data System (BOLD). There was high congruence between morphological and molecular classification, and COI provided effective species-level discrimination for nearly all putative species. No effect of geographic sampling was observed for COI sequence variation. For two families, including the Liparidae and Zoarcidae, for which morphological field identification was unable to resolve taxonomy, DNA barcoding revealed significant species-level divergence. However, the dataset lacked sufficient sensitivity for resolving species within theBathydracoandArtedidracogenera. Analysis of cytochromebfor these two genera also failed to resolve taxonomic identity. The data are discussed in relation to emergent priorities for additional taxonomic studies. We emphasize the utility of DNA barcoding in providing a valuable taxonomic framework for fundamental population studies through assigning life history stages or other morphologically ambiguous samples to parental species.
Volcanic features and the hydrological setting of Southern Thule, South Sandwich Islands
Authors: Allen Claire S. , Smellie John L.
Published: May 2008

This paper provides new observations of volcanic features and hydrological characteristics in and around Southern Thule, the southernmost group of islands in the South Sandwich Islands, including the first high-resolution bathymetric image of the Douglas Strait caldera. The South Sandwich Islands are the summits of several very large subduction-related volcanoes constructed at the eastern boundary of the Scotia Sea. Observations of the islands are scarce owing to their remote location and they are only rarely visited, yet the area is an active volcanic arc that is rapidly changing as a result of eruptions, including one (on Montagu Island) that has been ongoing for six years and is creating new land. The three islands that make up Southern Thule are morphologically different, and they illustrate different stages in the construction and evolution of islands in the South Sandwich group. We present the results of an acoustic and hydrographic survey that resulted in the first high-resolution, multibeam ‘swath’ image of the submarine Douglas Strait caldera. The results confirm the presence of a large sediment mound (c. 1000 m3 in volume) on the floor of the Douglas Strait caldera related to a flank collapse of Thule Island. The image also shows an extensive arcuate fault structure, interpreted as evidence that the caldera is nested, and its geomorphological freshness suggests that it is a very young feature that formed conceivably in the last few decades or centuries. The bathymetric image also reveals at least three cone- or mound-like structures within the caldera that may relate to renewed post-caldera volcanism (as pyroclastic cones and/or pillow mounds). Recently formed cones and faults associated with caldera rims are often associated with hydrothermal activity. However, temperature and salinity data collected within the caldera do not yet show any evidence of hydrothermal venting. The ocean surrounding Southern Thule has a prominent surface layer of low salinity water that is probably caused by a high meltwater flux derived from ice caps on the islands. This flux may have been enhanced by the recent warming trend observed in the Antarctic Peninsula, although volcano-related geothermal melting in the ice-filled Thule Island caldera may also contribute to the meltwater flux.
Biodiversity of the bacterioplankton in the surface waters around Southern Thule in the Southern Ocean
Authors: Pearce David A.
Published: May 2008

Seven independent clone libraries were constructed to study the biodiversity of the bacterioplankton in the surface waters around Southern Thule, South Sandwich Islands, in order to identify the species present, to determine the sample effort required to estimate the total diversity, and to determine whether the surface waters around Southern Thule represented a highly specialized local anomaly or a subset of the marine meta-community. In total, 672 clones generated 629 useable sequences. These 629 clones matched 278 different sequences deposited in the 16S rDNA sequence databases. The majority of the clones were related to marine microorganisms, many of which had been previously detected in permanently cold Arctic and Antarctic marine environments. Each clone library generated an average of 35.8 new sequence matches. 346 clones covered two-thirds of the total estimated diversity, while 438 clones covered three-quarters of the total estimated diversity. Above this number, the coverage tended to stabilize and a relatively large number of additional clones were required to improve coverage significantly, increasing at the rate of about one new sequence match per 100 new clones. Comparing the different clone libraries, eight matches occurred in each of the seven libraries, whilst fifty-five occurred in only one, suggesting that there might be a relatively small number of common dominant ubiquitous species, with a much larger underlying diversity or ‘seed bank’ from which this dominant diversity is drawn. This study suggests that the dominant bacterioplankton in the surface waters around Southern Thule represent a subset of the marine meta-community, whilst sub-dominant diversity appears to be a highly specialized local anomaly.
Biodiversity of echinoids and their epibionts around the Scotia Arc, Antarctica
Authors: Linse Katrin , Walker Lisa J. , Barnes David K.A.
Published: May 2008

The Scotia Arc, linking the Magellan region with the Antarctic Peninsula, comprises young and old islands both near continents and isolated, and is the only semi-continuous link between cool temperate and Antarctic environments. It is an ideal region for studies on how marine biodiversity changes across an extended transition zone. Echinoids (sea urchins) and their associated epibionts were found across depths from 91–1045 m, with 19 species from shelf and four from slope depths. The 23 species from 38 trawls represent 31% of all echinoid species known from the Southern Ocean and 38% of the shelf/upper slope echinoids. The specimens collected comprise representatives of the five families Cidaridae, Echinidae, Temnopleuridae, Schizasteridae and Pourtalesiidae. Echinoids are probably a good model for how well we know Antarctic shelf and slope megabenthos; none of the species we report are new to science but we found nine (39%) of our study species present at new localities, some thousands of kilometres from previous findings. New biogeographic ranges are illustrated forCtenocidaris gigantea,C. nutrix,C. spinosa,Abatus curvidens,A. ingens,A. shackletoni,Amphineustes rostratus,Tripylaster philippiandPourtalesia aurorae. Southern Ocean echinoids show eurybathy as the mean depth range of our study species was 1241 m and only one was at less than 500 m. The current view of echinoid dominance of super-abundance in the shallows seems to be not transferable to shelf and slope depths as only one of 38 trawls was dominated by echinoids. Current knowledge on maximum sizes in Antarctic echinoids seems to be good as our morphometric measurements were mainly within known size ranges. Regular echinoids increased predictably in mass with increasing test length, apart fromCtenocidaris spinosa. Tissue mass of cidaroid species was ~17%, but across irregular species varied from 17.7–8.9%. No epibionts were found on irregular echinoids or Echinidae but 70 cidaroids examined carried 51 species representing ten classes. Many of these species are reported as cidaroid epibionts for the first time. Cidaroids and their epibionts constituted > 38% of the total macrofaunal richness in the trawls they were present in. Echinoids and their epibionts clearly contribute significantly to Southern Ocean biodiversity but are minor components of biomass except in the shallows.
Figured Lifeworlds and Depositional Practices at Çatalhöyük
Authors: Meskell Lynn , Nakamura Carolyn , King Rachel , Farid Shahina
Published: May 2008

The corpus of figurines from Çatalhöyük has attracted the attention of diverse audiences but there has been an overwhelming focus on a selection of female figurines, many of which lack exact provenience. Excavation from 1961 to 1965 yielded more mundane examples classifiable as anthropomorphic, zoomorphic and abbreviated forms. New work attempts to balance the picture through various methods and strategies. The research presented here collates the artefacts from these early seasons with those retrieved from 1993 to 2006 to gain a fuller understanding of figurine practice. The figurines almost exclusively represent secondary deposition. We can now assess the number and type of figurines deposited in buildings, middens, burials and elsewhere. Reassessment of the entire corpus has prompted interrogation of the category of ‘figurine’ and reconsideration of the taxonomies along with other artefacts and image production at Çatalhöyük. Depositional practices at the site suggest processes of mobility and circulation that have rarely been considered in studies of figurines. Typical ‘representational’ or aesthetic approaches imply that the figurines were a special category with particular values of religiosity and gender; but attention to the archaeological context can imply meaning from the material practices within which ‘figurines’ were enmeshed.
Rainbow Colour and Power among the Waanyi of Northwest Queensland
Authors: Taçon Paul S.C.
Published: May 2008

In 2002, an investigation into the rock art of Waanyi country was undertaken in conjunction with ongoing archaeological excavation. Various subjects, styles and techniques were documented, associated oral history from Waanyi elders was recorded and the relationship to archaeological deposits was assessed. A large number of rainbow-like designs, in red or red-and-yellow, were recorded, along with a magnificent and very large red-and-yellow Rainbow Serpent. These and other images are discussed in relation to the travels of Ancestral Beings, stories and uses of coloured pigment and the use of local stone for both tools and the situating of important spiritual sites. Links to a network of other communities across northern and central Australia are highlighted. It is concluded that colour played a fundamental role in both expressing and maintaining relationships to places, Ancestral Beings and other groups of people. Important local differences can be seen in comparison to the ways in which colour has been used by Aboriginal people elsewhere. The research highlights ways in which the study of colour can prove valuable to archaeology globally.
Catastrophe, Revitalization and Religious Change on the Prehispanic North Coast of Peru
Authors: Jennings Justin
Published: May 2008

Although archaeologists have become increasingly interested in disaster, collapse and regeneration, there has been insufficient attention paid to the social and psychological impact of disasters. Disasters can stimulate far-reaching religious changes. This article is a case study of the fall of the Middle Sicán polity of northern Peru (ad 900–1100) that draws on both archaeology and oral tradition. Middle Sicán cosmology was centred on the Sicán Deity, which did not survive the polity's collapse. The god's demise and the revitalization movement that followed the Middle Sicán can only be understood by considering both how many of the people of the region conceptualized their world and the disasters that occurred.
The Triadic Causeways of Ichmul: Virtual Highways Becoming Actual Roads
Authors: Normark Johan
Published: May 2008

Cosmological models are common in Mayanist settlement studies. In such models, causeways are often said to follow various cosmological principles that are more or less the same from the Middle Formative to the present time. The models have been created by merging disparate data from ethnography, ethnohistory, iconography, epigraphy and archaeology into a single form where all the parts are determined by a common principle. The Terminal Classic triadic causeways at Ichmul, Yucatan, Mexico, could potentially be interpreted with such cosmological models. The evidence, however, does not fit these models. It is proposed, instead, with reference to the philosophers Henri Bergson, Gilles Deleuze and Manuel DeLanda, that settlement studies should focus only on what is present at the site without reliance on transcendent concepts such as culture or cosmology. The triadic causeways at Ichmul are seen as virtual processes that have the potential to become actual forms at every present moment.
Rituals of Sanctification and the Development of Standardized Temples in Oaxaca, Mexico
Authors: Redmond Elsa M. , Spencer Charles S.
Published: May 2008

Archaeological investigations at three Formative period sites near San Martín Tilcajete in the Valley of Oaxaca, Mexico, have recovered a sequence of temples. The temples span the period when the Zapotec state emerged with its capital at Monte Albán during the Late Monte Albán I phase (300–100 bc), coinciding with Monte Albán's conquest of neighbouring regions. Zapotec rituals of sanctification practised in pre-state times may have been affected by Monte Albán's military expansionism. The historically documented case of military expansion and political unification of the Hawaiian islands by the paramount, Kamehameha, shows similarities in the adoption of ideology and religious institutions. Among them are the establishment of standardized temples and the ascendance of a militaristic ideology and ritual order attuned to the early state rulers' coercive authority.
Food consumption, eating behaviour and self-esteem among singlev. married and cohabiting mothers and their 12-year-old children
Authors: Elfhag Kristina , Rasmussen Finn
Published: May 2008

Objective

Being a single mother may have implications for health behaviours that can also affect the child. More information about the food intakes and body weights in singlev. married/cohabiting mothers and in their children is needed. Psychological dimensions of eating behaviour and self-esteem are also of relevance to explore for single mothers and their children.

Design

Food style patterns were assessed by self-reported consumption of fruits, vegetables, sweets and soft drinks. Eating behaviour was measured by the Dutch Eating Behaviour Questionnaire and self-esteem by the Harter self-perception scale. The participants were 1781 mothers and their 12-year-old children, of whom 278 mothers (16 %) were single.

Results

Single mothers had lower intake of fruits and vegetables and lower self-worth compared to the married and cohabiting mothers, controlling for age, education and BMI. Although single mothers did not have a higher BMI, their daughters were heavier than girls from complete families. Daughters to single mothers furthermore had a higher intake of soft drinks, higher levels of restrained eating and lower self-worth. No such difference was found for the boys.

Conclusions

A lower sense of self-worth and lower intake of fruit and vegetables in single mothers could be seen in the context of the social disadvantages and less social support. Girls may be more inclined to be affected by family status than the boys, seen in a more unfortunate psychological pattern and a higher body weight. Boy’s health behaviours may be more unaffected by living in single families.
The molecular and cellular defects underlying Pelizaeus–Merzbacher disease
Authors: Woodward Karen J.
Published: May 2008

Pelizaeus–Merzbacher disease (PMD) is a recessive X-linked dysmyelinating disorder of the central nervous system (CNS). The most frequent cause of PMD is a genomic duplication of chromosome Xq22 including the region encoding the dosage-sensitive proteolipid protein 1 (PLP1) gene. ThePLP1duplications are heterogeneous in size, unlike duplications causing many other genomic disorders, and arise by a distinct molecular mechanism. Other causes of PMD includePLP1deletions, triplications and point mutations. Mutations in thePLP1gene can also give rise to spastic paraplegia type 2 (SPG2), an allelic form of the disease. Thus, there is a spectrum of CNS disorder from mild SPG2 to severe connatal PMD.PLP1encodes a major protein in CNS myelin and is abundantly expressed in oligodendrocytes, the myelinating cells of the CNS. Significant advances in our understanding of PMD have been achieved by investigating mutantPLP1in PMD patients, animal models and in vitro studies. How the differentPLP1mutations and dosage effects give rise to PMD is being revealed. Interestingly, the underlying causes of pathogenesis are distinct for each of the different genetic abnormalities. This article reviews the genetics of PMD and summarises the current knowledge of causative molecular and cellular mechanisms.
Variability of butterfat content in cacao (Theobroma cacao L.): combination and correlation with other seed-derived traits at the International Cocoa Genebank, Trinidad
Authors: Khan N. , Motilal L. A. , Sukha D. A. , Bekele F. L. , Iwaro A. D. , Bidaisee G. G. , Umaharan P. , Grierson L. H. , Zhang D.
Published: May 2008

Cocoa butterfat and cocoa powder are key economic products from the seeds of the cacao tree (Theobroma cacao L.). In this study, 323 accessions (comprised mainly of Upper Amazon Forasteros and Refractarios) from the International Cocoa Genebank, Trinidad were characterized for one biochemical and five morphological seed-derived traits. The data were analysed using non-parametric statistics including correlation analysis to identify promising parental candidates for future cacao breeding programmes. The Upper Amazon Forastero group had the greatest proportion of accessions with high butterfat content in cotyledons, whereas Refractario and Trinitario groups tended to contain more accessions with high butterfat content per fruit. The correlation of butterfat content of cotyledons with the dry mass of cotyledons was inconsistent in significance and direction. However, consistent significant positive correlations between butterfat content per fruit, cotyledon size and dry mass of cotyledons were found. The results suggested that butterfat content is a likely trait for independent selection but that selection for increased cotyledon size could lead to the selection of genotypes for high butterfat yield. Several promising accessions exhibited favourable levels of multiple traits and MATINA 1/7, CRU 51, AM 2/91 [POU], CRU 133, EET 58 [ECU] and POUND 18/A [POU] could be recommended as good choices for parental stock in breeding programmes for improving cacao butterfat content.
Diversity of Ethiopian tetraploid wheat germplasm: breeding opportunities for improving grain yield potential and quality traits
Authors: Teklu Yifru , Hammer Karl
Published: May 2008

In this paper, Shannon–Weaver diversity indices were employed to examine the phenotypic diversity in 271 Ethiopian tetraploid wheat accessions in relation to characters, regions of origin and altitude. Moreover, review of genetic diversity studies in Ethiopian tetraploid wheat was made to explore breeding opportunities. The diversity index varied widely across regions. Among the four altitudinal classes, the highest (0.72) and lowest (0.61) mean diversity indices were observed in altitude classes II and IV, respectively. The diversity index (H′) showed that most traits are polymorphic. The partitioning of the total phenotypic diversity into within- and among-region diversity indicated that 71% of the total variation was attributed to the within-region diversity. Principal component analysis was computed to examine the regional and altitudinal patterns of variation. On regional bases, the first four axes, whose eigenvalues are greater than 1, explained about 82% of the observed phenotypic diversity in the 271 tetraploid wheat accessions. On altitudinal bases, however, only the first two principal components explained 89.7% of the total variation. In general, phenotypic diversity showed considerable differences for each trait in different geographical regions and altitudinal classes which could be utilized in wheat improvement programmes. Breeding opportunities and strategies are suggested.
Polymorphism in Gloriosa superba
Authors: Ghosh Seemanti , Ghosh Biswajit , Jha Sumita
Published: May 2008

Gloriosa superba L. is a highly valued indigenous medicinal plant. It is available throughout India with noticeable variations in morphology and colchicine content. In the present study, morphological, phytochemical, cytological and molecular data are employed to screen the polymorphism, if present, in five different populations of G. superba L. Based on gross morphological traits, the plants can be grouped into two clusters: Amtala (AM) and Baruipur (BR) plants belonging to one cluster, and Siliguri (SG), Darjeeling (DJ) and Sikkim (SK) plants belonging to the other. Colchicine content of the tubers ranged from 0.06% in AM plants to 0.37% in BR plants. Cytological analysis revealed that the SK plants showed 44 chromosomes, i.e. tetraploid status, whereas the other four were diploid. Assessment of the karyomorphology of the four diploid populations indicated a close similarity between AM and BR plants, whereas the SG plants exhibited slightly different karyomorphology and lacked sm-type chromosomes. Random Amplified Polymorphic DNA (RAPD) analysis revealed 76% polymorphism among the populations. Cluster analysis using RAPD resulted in three main cluster groups; BR and SG plants clustered together indicating that they are most closely related when compared with other populations.
A remote sensing approach for estimating distributed daily net carbon dioxide flux in semiarid grasslands
Authors: Holifield Collins C. D. , Emmerich W. E. , Moran M. S. , Hernandez M. , Scott R. L. , Bryant R. B. , King D. M. , Verdugo C. L.
Published: May 2008

Semiarid systems compose a significant portion of the world's terrestrial area and may play an important role in the global carbon cycle. A model was developed using the relation between surface reflectance and temperature obtained from satellite imagery to determine a Water Deficit Index (WDI) that estimated distributed plant transpiration, and by extension carbon dioxide (CO2) flux, for a point in time. Relationships were developed to scale these instantaneous flux measurements up to daytime estimates, which were then used to obtain measures of nighttime flux. Satellite images were acquired for a 5‐year period (1996–2000) during which transpiration and net CO2 flux were measured for a semiarid grassland site in southeastern Arizona. Manual and automatic chamber data were also collected at the same site during the monsoon growing seasons of 2005 and 2006 and used to develop the relationship between and daytime and nighttime CO2 flux. Strong linear relationships were found between WDI‐derived instantaneous and daytime net CO2 flux estimates (R2 = 0.97), and between daytime and nighttime fluxes (R2 = 0.88). These relations were used to generate maps of distributed total daily net CO2 flux. The error for the model was within the range of error inherent in the data sets used to create it and remained reasonable when used with WDI values less than 0.9. This study demonstrated that remote sensing can offer a physically based means of obtaining daily net CO2 flux in semiarid grasslands.
High energy photon and electron bursts associated with upward lightning strokes
Authors: Yoshida S. , Morimoto T. , Ushio T. , Kawasaki Z.‐I. , Torii T. , Wang D. , Takagi N. , Watanabe T.
Published: May 2008

We conducted a field campaign during the Japanese winter thunderstorm season to observe radiation bursts associated with lightning discharges using a NaI scintillator and a thin plastic scintillator (PS), which primarily detects high energy electrons. We successfully recorded the bursts of high energy electrons with energies in excess of 100 keV from lightning discharges. We speculate that these high energy electrons were produced by high energy photon interactions near the PS. Our observations suggest that not only negative leaders but also positive leaders, which involve positive breakdowns, can cause an increase in the NaI count rate.
Box model studies of the secondary organic aerosol formation under different HC/NOxconditions using the subset of the Master Chemical Mechanism forα‐pinene oxidation
Authors: Xia Adam G. , Michelangeli Diane V. , Makar Paul A.
Published: May 2008

A subset of a near‐explicit Master Chemical Mechanism (v3.1) describingα‐pinene oxidation (976 reactions and 331 compounds) coupled with a gas/particle absorptive partitioning model is used as a benchmark for the study of secondary organic aerosol (SOA) formation within a box model under atmospheric relevant conditions of averaged HC/NOxratios between 0.18 and 8.43 (ppbvC/ppbv). Results from the detailed mechanism forα‐pinene oxidation show that total SOA mass increases as the HC/NOxratio increases within the studied range. The mass of peroxynitrates and the nitrates in the aerosol phase increases with increasing HC/NOxratio, despite decreases in the total (gas plus aerosol) mass of these species, because of increases in mass of organic peroxides and acids in these conditions. The fractional composition of aerosol mass indicates organic peroxides and acids dominate at high HC/NOxratios and peroxynitrates and nitrates dominate at low HC/NOxratios. In addition, 28 out of 149 condensable products are identified as important compounds for SOA formation. Of the organic nitrates, only two contribute consistently to organic aerosol mass. Organic peroxide and acid mass in the aerosol phase is distributed over a larger number of species. The 28 species identified here are suitable targets for future laboratory and field analysis of organic aerosols and are recommended for use in future mechanism reduction work.
Comparison of Ozone Monitoring Instrument UV Aerosol Products with Aqua/Moderate Resolution Imaging Spectroradiometer and Multiangle Imaging Spectroradiometer observations in 2006
Authors: Ahn Changwoo , Torres Omar , Bhartia Pawan K.
Published: May 2008

An assessment of the consistency of the Ozone Monitoring Instrument (OMI) aerosol products with the results from other satellite aerosol sensors is performed in this paper. The OMI aerosol products include the UltraViolet Aerosol Index (UVAI), Aerosol Absorption Optical Depth (AAOD), and Aerosol Extinction Optical Depth (AOD). The OMI AOD is compared with that from Aqua/Moderate Resolution Imaging Spectroradiometer (MODIS) and Terra/Multiangle Imaging Spectroradiometer (MISR). OMI‐retrieved AOD values are generally biased high with respect to MODIS measurements, likely as a result of a calibration offset. Subpixel cloud contamination is the second most important source of error. Other sources of error may contribute to the noise in the retrieval but not necessarily to the systematic bias. In spite of the bias, OMI retrievals show a high degree of correlation with MODIS observations. The analyses of daily cloud‐free collocated AOD data between OMI and MODIS show about 0.15 root mean square error on average relative to the linear fit. OMI also shows a reasonable agreement with MODIS and MISR observations in seasonal annual cycles of aerosols over most of the major emission sources of carbonaceous aerosols from biomass burning and mineral dust from deserts. The AAOD is less sensitive to cloud contamination than the AOD. In addition, the information content in the UVAI is well expressed as AAOD with higher correlation than AOD. However, subpixel cloud contamination of OMI footprint (13 × 24 km2 at nadir) is unavoidable, and retrieved AOD values tend to be overestimated with varying degrees of sensitivity as a function of viewing geometry and aerosol types selected.
Influence of nocturnal low‐level jet on turbulence structure and CO2 flux measurements over a forest canopy
Authors: Karipot Anandakumar , Leclerc Monique Y. , Zhang Gengsheng , Lewin Keith F. , Nagy John , Hendrey George R. , Starr Gregory
Published: May 2008

The present study analyzes features of nocturnal low‐level jets observed at the Florida AmeriFlux site and their influence on CO2 flux measurements over a tall forest canopy. At that location, two categories of nocturnal flow are commonly observed, one with a strong low‐level jet throughout the night and the other without. Jets of diverse speed and height are observed during nearly 70% of the nocturnal periods over a 3‐month campaign, of which almost 50% are strong jets with speed higher than 10 m s−1 and height in the range 200–400 m. Strong jet activity contributes to weak atmospheric stabilities with gradient Richardson numbers lower than 0.2 and higher friction velocities (0.2 to 0.6 m s−1) attributed to enhanced canopy turbulence. The canopy shear length scale exhibits a linear relationship with jet shear. Jet periods also show dominant downward transport of turbulent kinetic energy and turbulent CO2 fluxes in the range 2 to 8 μmol m−2 s−1. The difference between the net ecosystem exchange (NEE) at two levels above the canopy adds on average, flux contribution of 1.25 μmol m−2 s−1 (18% of the average NEE at z = 1.4h, h is the canopy height) to CO2 exchange during periods characterized by strong jets. A comparison of CO2 and wind velocity Fourier spectra and cospectra between periods with dissimilar jet activity shows larger low‐frequency spectral contributions in the strong jet case, supporting the possibility of variance and flux contributions at scales comparable to the jet height.
Microgenetic algorithms and artificial neural networks to assess minimum data requirements for prediction of pesticide concentrations in shallow groundwater on a regional scale
Authors: Sahoo Goloka Behari , Ray Chittaranjan
Published: May 2008

Artificial neural networks (ANNs) have been extensively used for forecasting problems involving water quantity and quality. In most cases, the geometry and model parameters of the ANN are set using a trial‐and‐error approach to achieve better network generalization ability, whereby the available data are divided arbitrarily into training, testing, and validation subsets. It has been shown that using the arbitrary sample selection method to assign samples into the training subset commonly results in the inclusion of samples from densely clustered regions and omission of samples from sparsely represented regions. This paper presents a systematic approach using the self‐organizing map (SOM) clustering technique that identifies which samples and determines how many samples should be included in each of the three subsets required by ANN for optimum predictive performance efficiency. In addition, this paper presents the microgenetic algorithms (μGA) that optimize ANN's geometry and model parameters in terms of the correlation coefficient (R). In the sensitivity analysis, μGA model parameters are found to be least sensitive to the optimum R value, while ANN's predictive performance is significantly affected by (1) the poor selection of its geometry and model parameters and (2) the arbitrary selection of samples for the three subsets of data used. It is demonstrated that the μGA‐ANN model using the SOM technique for data division outperforms the μGA‐ANN model using arbitrary data division. For the training subset, the model using the SOM technique identifies samples that are representative of the region, requiring only 20% of the total samples, whereas the arbitrary sample selection method requires 50–90%. Because resampling on a regional scale is expensive and time consuming, substantial cost and time could be saved if resampling could be done only on the 20% representative drinking water wells.
A Markov chain Monte Carlo algorithm for upscaled soil‐vegetation‐atmosphere‐transfer modeling to evaluate satellite‐based soil moisture measurements
Authors: Das N. N. , Mohanty B. P. , Njoku E. G.
Published: May 2008

A Markov chain Monte Carlo (MCMC) based algorithm was developed to derive upscaled land surface parameters for a soil‐vegetation‐atmosphere‐transfer (SVAT) model using time series data of satellite‐measured atmospheric forcings (e.g., precipitation), and land surface states (e.g., soil moisture and vegetation). This study focuses especially on the evaluation of soil moisture measurements of the Aqua satellite based Advanced Microwave Scanning Radiometer (AMSR‐E) instrument using the new MCMC‐based scaling algorithm. Soil moisture evolution was modeled at a spatial scale comparable to the AMSR‐E soil moisture product, with the hypothesis that the characterization of soil microwave emissions and their variations with space and time on soil surface within the AMSR‐E footprint can be represented by an ensemble of upscaled soil hydraulic parameters. We demonstrated the features of the MCMC‐based parameter upscaling algorithm (from field to satellite footprint scale) within a SVAT model framework to evaluate the satellite‐based brightness temperature/soil moisture measurements for different hydroclimatic regions, and identified the temporal effects of vegetation (leaf area index) and other environmental factors on AMSR‐E based remotely sensed soil moisture data. The SVAT modeling applied for different hydroclimatic regions revealed the limitation of AMSR‐E measurements in high‐vegetation regions. The study also suggests that inclusion of soil moisture evolution from the proposed upscaled SVAT model with AMSR‐E measurements in data assimilation routine will improve the quality of soil moisture assessment in a footprint scale. The technique also has the potential to derive upscaled parameters of other geophysical properties used in remote sensing of land surface states. The developed MCMC algorithm with SVAT model can be very useful for land‐atmosphere interaction studies and further understanding of the physical controls responsible for soil moisture dynamics at different scales.