bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid recovery from the Late Ordovician mass extinction
Authors: Krug A. Z. , Patzkowsky M. E.
Published: December 2004

Understanding the evolutionary role of mass extinctions requires detailed knowledge of postextinction recoveries. However, most models of recovery hinge on a direct reading of the fossil record, and several recent studies have suggested that the fossil record is especially incomplete for recovery intervals immediately after mass extinctions. Here, we analyze a database of genus occurrences for the paleocontinent of Laurentia to determine the effects of regional processes on recovery and the effects of variations in preservation and sampling intensity on perceived diversity trends and taxonomic rates during the Late Ordovician mass extinction and Early Silurian recovery. After accounting for variation in sampling intensity, we find that marine benthic diversity in Laurentia recovered to preextinction levels within 5 million years, which is nearly 15 million years sooner than suggested by global compilations. The rapid turnover in Laurentia suggests that processes such as immigration may have been particularly important in the recovery of regional ecosystems from environmental perturbations. However, additional regional studies and a global analysis of the Late Ordovician mass extinction that accounts for variations in sampling intensity are necessary to confirm this pattern. Because the record of Phanerozoic mass extinctions and postextinction recoveries may be compromised by variations in preservation and sampling intensity, all should be reevaluated with sampling-standardized analyses if the evolutionary role of mass extinctions is to be fully understood.
Adaptation to fasting by glycerol transport through aquaporin 7 in adipose tissue
Authors: Maeda Norikazu , Funahashi Tohru , Hibuse Toshiyuki , Nagasawa Azumi , Kishida Ken , Kuriyama Hiroshi , Nakamura Tadashi , Kihara Shinji , Shimomura Iichiro , Matsuzawa Yuji
Published: December 2004

Adipocytes hydrolyze triglycerides and secrete free fatty acids and glycerol into the circulation. The molecular mechanism involved in glycerol transport from adipocytes has not been elucidated. Here, we investigated glycerol and glucose metabolism in mice lacking aquaporin 7 (
Aqp7
), a member of the aquaglyceroporins expressed in adipose tissue, and demonstrated that
Aqp7
functions as a glycerol gateway molecule
in vivo. Aqp7
-knockout (KO) mice had lower plasma glycerol levels compared with WT mice but had normal plasma free fatty acid levels. The increase in plasma glycerol level in response to β
3
-adrenergic agonist was severely impaired in KO mice. Epinephrine-stimulated glycerol secretion was also impaired in
Aqp7
knockdown adipocytes. During prolonged fasting, plasma glycerol was elevated and the plasma glucose level was maintained in WT mice. In contrast, KO mice showed a disrupted increase of plasma glycerol and rapid reduction of plasma glucose during prolonged fasting. Our findings indicate that the lack of effective glycerol transport from adipocytes by glycerol gateway molecule causes defective adaptation to prolonged fasting.
Fermented beverages of pre- and proto-historic China
Authors: McGovern Patrick E. , Zhang Juzhong , Tang Jigen , Zhang Zhiqing , Hall Gretchen R. , Moreau Robert A. , Nuñez Alberto , Butrym Eric D. , Richards Michael P. , Wang Chen-shan , Cheng Guangsheng , Zhao Zhijun , Wang Changsui
Published: December 2004

Chemical analyses of ancient organics absorbed into pottery jars from the early Neolithic village of Jiahu in Henan province in China have revealed that a mixed fermented beverage of rice, honey, and fruit (hawthorn fruit and/or grape) was being produced as early as the seventh millennium before Christ (B.C.). This prehistoric drink paved the way for unique cereal beverages of the proto-historic second millennium B.C., remarkably preserved as liquids inside sealed bronze vessels of the Shang and Western Zhou Dynasties. These findings provide direct evidence for fermented beverages in ancient Chinese culture, which were of considerable social, religious, and medical significance, and help elucidate their earliest descriptions in the Shang Dynasty oracle inscriptions.
Ezrin–radixin–moesin (ERM)-binding phosphoprotein 50 organizes ERM proteins at the apical membrane of polarized epithelia
Authors: Morales Fabiana C. , Takahashi Yoko , Kreimann Erica L. , Georgescu Maria-Magdalena
Published: December 2004

Ezrin–radixin–moesin (ERM) proteins regulate the organization and function of specific cortical structures in polarized epithelial cells by connecting filamentous (F)-actin to plasma membrane proteins. The contribution of ERM proteins to these structures depends on a conformational change to an active state in which the C-terminal region interacts with F-actin and the N-terminal domain interacts with membrane ligands. The specific ligands necessary for stabilizing ERM proteins at the membrane are not known. By generating mice deficient for ERM-binding phosphoprotein 50/Na
+
/H
+
exchanger regulatory factor 1 (EBP50/NHERF1), which binds the N-terminal domain of ERM proteins, we found that EBP50 is required for the maintenance of active ERM proteins at the cortical brush border membranes (BBM) of polarized epithelia. In EBP50(–/–) mice, ERM proteins were significantly decreased specifically in BBM from kidney and small intestine epithelial cells, whereas they remained unchanged in the cytoplasm. In wild-type animals, EBP50 was localized to the BBM compartment where it was processed by cleavage of the ERM-binding motif. In BBM, active ERM proteins formed distinct complexes with full-length EBP50 and with F-actin, suggesting a switch mechanism in which proteolytically processed EBP50 would release ERM proteins to complex with F-actin. The structural defects found in the EBP50(–/–) intestinal microvilli were reminiscent of those described in ezrin(–/–) mice, suggesting a role for EBP50 in organizing apical epithelial membranes.
Major reduction of atherosclerosis in fractalkine (CX3CL1)-deficient mice is at the brachiocephalic artery, not the aortic root
Authors: Teupser Daniel , Pavlides Stephanos , Tan Marietta , Gutierrez-Ramos Jose-Carlos , Kolbeck Roland , Breslow Jan L.
Published: December 2004

Fractalkine (CX3CL1) is of particular interest in atherogenesis because it can serve as an adhesion molecule and a chemokine. Fractalkine and its receptor CX3CR1 are expressed in atherosclerotic lesions of humans and mice. However, the effect of fractalkine deficiency on atherosclerosis susceptibility is unknown. Fractalkine-deficient mice on the C57BL/6 (B6) background were bred to the atherosclerosis-sensitizing B6.ApoE
-/-
and B6.LDLR
-/-
backgrounds. Compared with controls, aortic-root lesion area was unchanged in fractalkine-deficient male and female B6.ApoE
-/-
mice at 16 weeks of age and males at 12 weeks of age, but it was mildly reduced (30%,
P
= 0.005) in females at 12 weeks of age. In contrast, lesion area at the brachiocephalic artery (BCA) was reduced dramatically by ≈85% in fractalkine-deficient females [42,251 ± 26,136 μm
2
(
n
= 15) vs. 6,538 ± 11,320 μm
2
;(
n
= 24),
P
< 0.0001] and males [36,911 ± 32,504 μm
2
(
n
= 24) vs. 6,768 ± 8,595 μm
2
(
n
= 14);
P
= 0.001] at 16 weeks of age. Fractalkine-deficient B6.ApoE
-/-
mice were comparable with controls in body weight, plasma cholesterol, plasma high-density lipoprotein cholesterol and white blood cell counts. On the B6.LDLR
-/-
background, lesion areas were reduced by 35% at the aortic root (
P
< 0.01) and by 50% at the BCA (
P
< 0.05) in fractalkine-deficient females at 16 weeks of age. Lesions in fractalkine-deficient mice on the B6.ApoE
-/-
and B6.LDLR
-/-
backgrounds were less complex and contained significantly fewer macrophages than controls. In conclusion, the major reduction of atherosclerosis in fractalkine-deficient mice appears to be at the BCA rather than the aortic root.
A vesicle bioreactor as a step toward an artificial cell assembly
Authors: Noireaux Vincent , Libchaber Albert
Published: December 2004

An
Escherichia coli
cell-free expression system is encapsulated in a phospholipid vesicle to build a cell-like bioreactor. Large unilamellar vesicles containing extracts are produced in an oil–extract emulsion. To form a bilayer the vesicles are transferred into a feeding solution that contains ribonucleotides and amino acids. Transcription–translation of plasmid genes is isolated in the vesicles. Whereas in bulk solution expression of enhanced GFP stops after 2 h, inside the vesicle permeability of the membrane to the feeding solution prolongs the expression for up to 5 h. To solve the energy and material limitations and increase the capacity of the reactor, the α-hemolysin pore protein from
Staphylococcus aureus
is expressed inside the vesicle to create a selective permeability for nutrients. The reactor can then sustain expression for up to 4 days with a protein production of 30 μM after 4 days. Oxygen diffusion and osmotic pressure are critical parameters to maintain expression and avoid vesicle burst.
Postzygotic isolating factor in sympatric speciation in
Rhagoletis
flies: Reduced response of hybrids to parental host-fruit odors
Authors: Linn Charles E. , Dambroski Hattie R. , Feder Jeffrey L. , Berlocher Stewart H. , Nojima Satoshi , Roelofs Wendell L.
Published: December 2004

Rhagoletis pomonella
is a model for sympatric speciation (divergence without geographic isolation) by means of host-plant shifts. Many
Rhagoletis
species are known to use fruit odor as a key olfactory cue to distinguish among their respective host plants. Because
Rhagoletis
rendezvous on or near the unabscised fruit of their hosts to mate, behavioral preferences for fruit odor translate directly into premating reproductive isolation among flies. Here, we report that reciprocal F
1
hybrids between the apple and hawthorn host races of
R. pomonella
, as well as between the host races and an undescribed sibling species infesting
Cornus florida
(flowering dogwood) do not respond to host fruit volatiles in wind-tunnel assays at doses that elicit maximal directed flight in parental flies. The reduced ability of hybrids to orient to fruit volatiles could result from a conflict between neural pathways for preference and avoidance behaviors, and it suggests that hybrids might suffer a fitness disadvantage for finding fruit in nature. Therefore, host-specific mating may play a dual role as an important postzygotic as well as a premating reproductive barrier to isolate sympatric
Rhagoletis
flies.
Update on Prevention of Mother‐to‐Child HIV Transmission
Authors: Mofenson Lynne M.
Published: December 2004

The pediatric HIV epidemic in the US and other more developed countries changed dramatically after February 1994, when the results of PACTG 076 demonstrated that a triple regimen of ZDV reduced the risk of perinatal transmission by nearly 70%. Incorporation of ZDV prophylaxis into clinical practice, together with increased prenatal HIV counseling and testing, rapidly resulted in a significant decline in perinatal transmission and a concomitant decrease in the number of reported pediatric AIDS cases in the US. Transmission rates of 3–6% have been reported in various cohort studies with ZDV prophylaxis alone, and of 1–2% when ZDV is combined
with elective Cesarean delivery or when women are treated with highly active antiretroviral regimens that reduce maternal viral load to unquantifiable levels. Additionally, several short antiretroviral regimens, including those that require administration only during the intrapartum and early postpartum periods, have been shown to decrease perinatal transmission. These regimens provide effective intervention even for HIV‐infected pregnant
women who have not received antiretroviral therapy and are identified late in pregnancy or for the first time at delivery through rapid HIV testing.

However, this success has been partially offset by increasing HIV infection rates among young women, high adolescent pregnancy rates among at‐risk populations, continued failure to identify HIV infection during pregnancy and inadequate prenatal care among HIV‐infected women, particularly those using drugs. Additionally, the impact of evolving patterns of antiretroviral drug resistance on efficacy of prophylaxis is not known. As
combination antiretroviral therapy becomes the standard of care for pregnant women in developed countries, evaluation of their infants for short‐ or long‐term adverse consequences of intrauterine antiretroviral exposure is also a priority. Finally, clinical trials have identified short‐course antiretroviral prophylaxis regimens that are effective and safe in resource‐poor countries; however, transmission of HIV via breast milk remains a concern.
Improving Universal Prenatal Screening for Human Immunodeﬁciency Virus
Authors: Anderson Brenna L. , Simhan Hyagriv N. , Landers Daniel V.
Published: December 2004

Objective: To evaluate the effect of implementation of a human immunodeficiency virus (HIV) educational intervention on universal screening for HIV in a prenatal clinic setting.

Methods: In this retrospective cohort study, frequencies of offering and acceptance of HIV testing were compared before and after an educational intervention performed by an HIV‐focused nurse. The records of 293 women seeking prenatal care before the intervention and 206 women seeking prenatal care after the intervention were reviewed for offering and acceptance of HIV testing. Fisher′s exact test and logistic regression were used to evaluate the relationship between the educational intervention and the offering and acceptance of HIV testing.

Results: The frequency of HIV test offering at first visit and test acceptance before the educational intervention were 96.5% and 74.8%, respectively, and after the intervention were 99.5% and 84.3%, respectively. This
improvement in offering (3% change) and acceptance (9.5% change) was statistically significant (offering at first visit: OR = 7.27, 95% CI = 1.02 to 316.9; test acceptance: OR = 1.82, 95% CI = 1.14 to 2.88). Test acceptance was statistically significantly improved in the post‐intervention group after controlling for confounding variables (OR = 2.02, 95% CI = 1.2 to 3.39).

Conclusion: The addition of an HIV‐focused nurse to a clinic setting improved the frequency of test offering at first visit and of acceptance of HIV testing by pregnant women.
Vaginal Flora Morphotypic Profiles and Assessment of BacterialVaginosis in Women at Risk for HIV Infection
Authors: Tohill Beth C. , Heilig Charles M. , Klein Robert S. , Rompalo Anne , Cu-Uvin Susan , Brown William , Duerr Ann
Published: December 2004

Specific morphotypic profiles of normal and abnormal vaginal flora, including bacterial vaginosis (BV), were characterized. A prospective study of 350 women yielded concurrent Gram‐stain data and clinical assessment (n = 3455 visits). Microbiological profiles were constructed by Gram stain. Eight profile definitions were based
on dichotomizing the levels of Lactobacillus, Gardnerella, and curved, Gram‐negative bacillus (Mobiluncus) morphotypes. Of these, two were rare, and the other six demonstrated a graded association with the clinical
components of BV. The proposed profiles from the Gram stain reflect the morphotypic categories describing vaginal flora that may enable clearer elucidation of gynecologic and obstetric outcomes in various populations.
Reframing Sovereignty? Sub-State National Societies and Contemporary Challenges to the Nation-State
Authors: Tierney Stephen
Published: December 2004

Over the past 30 years, sub-state national societies in a number of developed liberal democracies—particularly Quebec, Catalonia, and Scotland within Canada, Spain, and the United Kingdom respectively—have both reasserted their national distinctiveness and demanded recognition of it in constitutional terms.1This re-emergence of sub-state national sentiment within industrially advanced States, and the struggle for constitutional change which has accompanied it, are considered by many observers to be strangely incongruous at a time of economic and cultural ‘globalization’ where the power of the nation- State itself seems to be waning.2Why do sub-state nations, the common refrain asks, seek statehood when the very concept of State sovereignty is losing its meaning? This article will argue, however, that the rise of sub-state nationalism even at a time when the resilience of State sovereignty is itself coming into question, is in fact not as paradoxical as it might at first appear, at least insofar as this process is taking place within developed democracies.3It will be contended that the elaborate constitutional programmes which are now beingadvanced by sub-state nationalist movements for the reform of their respective host States are inmany respects informed by, and reflective of, wider transformations in the patterns of State sovereignty.
Shorter Articles, Comments, and Notes: ‘Clear and Present Danger’: Responses to Terrorism
Authors: Lowe Vaughan
Published: December 2004

It was Oliver Wendell Holmes who used the words ‘clear and present danger’ in the judgment of the US Supreme Court in the Schenk case in 1919.1 The Court upheld the conviction of Charles Schenk, general secretary of the American Socialist Party, under the 1917 Espionage Act, which prohibited attempts to obstruct military recruitment. Schenk had distributed leaflets allegedly calculated to cause insubordination and obstruction among recruits. He argued that his conviction was incompatible with the freedom of speech guaranteed by the First Amendment.
The End of Occupation: Iraq 2004
Authors: Roberts Adam
Published: December 2004

Can a military occupation-and all the responsibilities of an occupying power as laid down in the laws of war—end at a single moment in time, and without the actual departure of the foreign military forces involved? This is the core question posed by the planned twin events of 28 June 2004 in Iraq: (1) the assumption of full authority by the sovereign Interim Government of Iraq, and(2) the proclaimed end of the US-led occupation of Iraq that had begun during the war of March-April 2003.
Book reviews
Authors: authors Various
Published: December 2004

Four book reviews in the January 2005 issue of
Notes and Records:
Review Paper. Ancient DNA
Authors: Willerslev Eske , Cooper Alan
Published: December 2004

In the past two decades, ancient DNA research has progressed from the retrieval of small fragments of mitochondrial DNA from a few late Holocene specimens, to large-scale studies of ancient populations, phenotypically important nuclear loci, and even whole mitochondrial genome sequences of extinct species. However, the field is still regularly marred by erroneous reports, which underestimate the extent of contamination within laboratories and samples themselves. An improved understanding of these processes and the effects of damage on ancient DNA templates has started to provide a more robust basis for research. Recent methodological advances have included the characterization of Pleistocene mammal populations and discoveries of DNA preserved in ancient sediments. Increasingly, ancient genetic information is providing a unique means to test assumptions used in evolutionary and population genetics studies to reconstruct the past. Initial results have revealed surprisingly complex population histories, and indicate that modern phylogeographic studies may give misleading impressions about even the recent evolutionary past. With the advent and uptake of appropriate methodologies, ancient DNA is now positioned to become a powerful tool in biological research and is also evolving new and unexpected uses, such as in the search for extinct or extant life in the deep biosphere and on other planets.
The Political Economy of Supranational Institutions: Two Recent Contrary Standpoints
Authors: Bergs Rolf
Published: December 2004

Book reviewed in this article:

Inge Kaul, Isabelle Grunberg and Marc A. Stern, Global Public Goods: International Cooperation in the 21st Century

Lloyd Gruber, Ruling the World: Power Politics and the Rise of Supranational Institutions
Is There a Place for Virtual Poverty Funds in Pro‐Poor Public Spending Reform? Lessons from Uganda's PAF
Authors: Williamson Tim , Canagarajah Sudharshan
Published: December 2004

Various developing countries with weak public expenditure management systems are establishing virtual poverty funds (VPFs), drawing on the experience of Uganda's Poverty Action Fund. As a mechanism for tagging and tracking the performance of specific poverty‐reducing expenditures in the budget, a VPF can be useful. However, this article argues that such devices should be treated from the outset as transitional, and as part of wider processes of strengthening public expenditure management; otherwise, they can seriously distort public expenditure allocations and management systems, potentially undermining growth. Emphasis needs to be placed on identifying the right balance of expenditures in the entire budget; improving the effectiveness and efficiency of existing allocations; and developing better public‐sector policies for promoting pro‐poor private sector growth.
Linguistic and conceptual development from one to six years: an introduction
Authors: Floccia Caroline , Goslin Jeremy , Schneider Roland , Thommen Evelyne
Published: December 2004

In this section nine experimental papers are presented, a selection chosen by both developmental psycholinguists and psychologists as being of special interest to the area of concept acquisition. Although many points (both theoretical and methodological) put the two fields of research in opposition, these papers show the possibilities of a coherent overview of development, covering both language and conceptual development. This is especially important in the overlapping areas of research concerning the sound‐to‐meaning mapping processes of lexical acquisition, and the appearance of words referring to mental verbs in the child's vocabulary.
Aspects of grammatical development in young French children with SLI
Authors: Hamann Cornelia , Ohayon Stéphanie , Dubé Sébastien , Frauenfelder Ulrich H. , Rizzi Luigi , Starke Michal , Zesiger Pascal
Published: December 2004

This paper presents an exploratory study of the spontaneous production of 11 French children clinically diagnosed as specific language impaired (SLI). In a cross‐sectional study of the children under and over 5 years of age, we investigate the production of finite and non‐finite verbal forms, of sentences with overt and null subjects, and of pronominal clitics. A comparison between younger and older children with SLI highlights developmental patterns which parallel normal syntactic development in important respects, though at a slower pace. An area of difficulty which clearly persists for the older group involves the domain of pronominal complement clitics.
Self–other and third‐person categorization in normal and autistic children
Authors: Peeters Guido , Grobben Goele , Hendrickx Ann , Van den Eede Steven , Verlinden Karen
Published: December 2004

Social information processing has been found to vary as a function of whether perceivers categorize individuals in terms of self and other (SO‐categorization) or using categories associated with the third pronominal person (3P‐categorization). Normal children aged 3–8, autistic children aged 5–9 and adult students were presented with decision tasks that enabled us to assess the use of SO‐ and 3P‐categorizations. A breakthrough of the SO‐categorization was observed at age 5. The hypothesis that 3P‐categorization precedes SO‐categorization was strongly disconfirmed, only adults showing consistent 3P‐categorization. Although previous research suggested a strong association between SO‐categorization and ‘I–Thou’ related social understanding, performances of autistic children suggested that impaired understanding of mental life does not detract from the ability to use SO‐categorization.
Prosodic structure and syntactic acquisition: the case of the head‐direction parameter
Authors: Christophe Anne , Nespor Marina , Teresa Guasti Maria , Van Ooyen Brit
Published: December 2004

We propose that infants may learn about the relative order of heads and complements in their language before they know many words, on the basis of prosodic information (relative prominence within phonological phrases). We present experimental evidence that 6–12‐week‐old infants can discriminate two languages that differ in their head direction and its prosodic correlate, but have otherwise similar phonological properties (i.e. French and Turkish). This result supports the hypothesis that infants may use this kind of prosodic information to bootstrap their acquisition of word order.
STRATEGIC NEGOTIATION FOR SHARING A RESOURCE   BETWEEN TWO AGENTS*
Authors: Kraus Sarit , Schechter Orna
Published: December 2004

In this article, we propose a strategic negotiation model that enables self‐motivated rational agents to share resources. The strategic negotiation model takes the passage of time during the negotiation process itself into account. The model considers bilateral negotiations in situations characterized by complete information, in which one agent loses over time whereas the other gains over time. Using this negotiation mechanism, autonomous agents apply simple and stable negotiation strategies that result in efficient agreements without delay, even when there are dynamic changes in the environment. Simulation results show that our mechanism performs as well as a centralized scheduler and also has the property of balancing the resources' usage.
HIGH‐DIMENSIONAL LEARNING FRAMEWORK   FOR ADAPTIVE DOCUMENT FILTERING*
Authors: Lam Wai , Leung Yu Kwok
Published: December 2004

We investigate the unique requirements of the adaptive textual document filtering problem and propose a new high‐dimensional on‐line learning framework, known as the REPGER (relevant feature pool with good training example retrieval rule) algorithm to tackle this problem. Our algorithm possesses three characteristics. First, it maintains a pool of selective features with potentially high predictive power to predict document relevance. Second, besides retrieving documents according to their predicted relevance, it also retrieves incoming documents that are considered good training examples. Third, it can dynamically adjust the dissemination threshold throughout the filtering process so as to maintain a good filtering performance in a fully interactive environment. We have conducted experiments on three document corpora, namely, Associated Press, Foreign Broadcast Information Service, andWall Street Journalto compare the performance of our REPGER algorithm with two existing on‐line learning algorithms. The results demonstrate that our REPGER algorithm gives better performance most of the time. Comparison with the TREC (Text Retrieval Conference) adaptive text filtering track participants was also made. The result shows that our REPGER algorithm is comparable to them.
THE DESIGN OF A STATISTICAL ALGORITHM FOR RESOLVING STRUCTURAL AMBIGUITY IN “V NP1 usde NP0”
Authors: Li Wenjie , Wong Kam‐Fai
Published: December 2004

The existence of structural ambiguity in modifying clauses renders noun phrase (NP) extraction from running Chinese texts complicated. It is shown from previous experiments that nearly 33% of the errors in an NP extractor were actually caused by the use of clause modifiers. For example, consider the sequence “V + NP1+ (of) + NP0.” It can be interpreted as two alternatives, a verb phrase (i.e., [V[NP1++ NP0]NP]VP) or a noun phrase (i.e., [[V NP1]VP++ NP0]NP). To resolve this ambiguity, syntactical, contextual, and semantics‐based approaches are investigated in this article. The conclusion is that the problem can be overcome only when the semantic knowledge about words is adopted. Therefore, a structural disambiguation algorithm based on lexical association is proposed. The algorithm uses the semantic class relation between a word pair derived from a standard Chinese thesaurus, , to work out whether a noun phrase or a verb phrase has a stronger lexical association within the collocation. This can, in turn, determine the intended phrase structure. With the proposed algorithm, the best accuracy and coverage are 79% and 100%, respectively. The experiment also shows that the backed‐off model is more effective for this purpose. With this disambiguation algorithm, parsing performance can be significantly improved.
Vortex Tracking and Visualisation in a Flow Past a Tapered Cylinder
Authors: Reinders Freek , Sadarjoen I. Ari , Vrolijk Benjamin , Post Frits H.
Published: December 2004

In this paper we explore a novel combined application of two of our existing visualisation techniques to thetracking of 3D vortex tubes in an unsteady flow. The applied techniques are the winding‐angle vortex extractiontechnique based on streamline geometry, and the attribute‐based feature tracking technique. We have applied theseto the well‐known case of an unsteady 3D flow past a tapered cylinder.

First, 2D vortices are detected in a number of horizontal slices for each time step, by means of the winding‐anglevortex extraction method. For each 2D vortex a number of attributes are calculated and stored. These vorticesare visualised by a special type of ellipse icons, showing the position, shape and rotational direction and speed ineach slice.

Next, for each time step, 3D vortex tubes are constructed from the 2D vortices by applying the feature trackingprocedure in a spatial dimension to connect the corresponding vortices in adjacent slices. The result is a graphattribute set with the 2D vortex attributes in the nodes and the spatial correspondences as edges.

Finally, the 3D vortex tubes are tracked in time using the same tracking procedure, for finding the correspondingtubes in successive time steps. The result is a description of the evolution of the 3D vortices. An interactive, time‐dependentvisualisation is generated using the temporal correspondences of each vortex tube. This analysis revealsa number of interesting patterns.

ACM CSS: I.3.8 Computer Graphics—Applications
SVG Linearization and Accessibility
Authors: Herman Ivan , Dardailler Daniel
Published: December 2004

The usage of SVG (Scaleable Vector Graphics) creates new possibilities as well as new challenges for theaccessibility of Web sites. This paper presents a metadata vocabulary to describe the information content ofan SVG file geared towards accessibility. When used with a suitable tool, this metadata description can helpin generating a textual (``linear'') version of the content, which can be used for users with disabilities or withnon‐visual devices.

Although this paper concentrates on SVG, i.e. on graphics on the Web, the metadata approach and vocabularypresented below can be applied in relation to other technologies, too. Indeed, accessibility issues have a muchwider significance, and have an effect on areas like CAD, cartography, or information visualization. Hence, theexperiences of the work presented below may also be useful for practitioners in other areas.

ACM CSS: I.3.4 Graphics Utilities—Graphics Packages, I.3.6 Methodology and Techniques—Graphics datastructures and data types, Standards, K.4.2 Social Issues—Assistive technologies for persons with disabilities
Adaptive Zooming in Web Cartography
Authors: Cecconi Alesandro , Galanda Martin
Published: December 2004

Beyond any doubt much of the current web mapping and web GIS applications lack cartographic quality. Thereasons aren't only the technical limitations related to Internet delivery, but also the neglect of one of the maincartographic principles of digital mapping, namely adaptive zooming. Adaptive zooming describes the adjustmentof a map, its contents and the symbolization to target scale in consequence of a zooming operation. The approachdescribed in this paper proposes the combination of two commonly known concepts: on the one hand levelsof detail (LoD) for those object classes, that require high computational cost for the automated generalizationprocess (e.g. buildings, road network); on the other hand an on‐the‐fly generalization for those object classeswhich can be generalized by less complex methods and algorithms (e.g. rivers, lakes). Realizing such interactiveand dynamic concept for web mapping requires the use of vector based visualization tools. The data format bestmeeting the criteria is the W3C standard Scalable Vector Graphics (SVG). Thus, it has been used to implementthe presented ideas in a prototype application for topographic web mapping based on the landscape modelVECTOR25 of the Swiss Federal Office of Topography.
The Perspective Silhouette of a Canal Surface
Authors: Kim Ku‐Jin , Lee In‐Kwon
Published: December 2004

We present an efficient and robust algorithm for parameterizing the perspective silhouette of a canal surface and detecting each connected component of the silhouette. A canal surface is the envelope of a moving sphere with varying radius, defined by the trajectory

C(t)
of its center and a radius function

r(t)
. This moving sphere,

S(t)
, touches the canal surface at a characteristic circle

K(t)
. We decompose the canal surface into a set of characteristic circles, compute the silhouette points on each characteristic circle, and then parameterize the silhouette curve. The perspective silhouette of the sphere

S(t)
from a given viewpoint consists of a circle

Q(t)
; by identifying the values of

t

at which

K(t)
and

Q(t)
touch, we can find all the connected components of the silhouette curve of the canal surface.

ACM CSS: I.3.7 Computer Graphics–Three Dimensional Graphics and Realism
Two‐dimensional Potential Fields for Advanced Implicit Modeling Operators
Authors: Barthe L. , Dodgson N. A. , Sabin M. A. , Wyvill B. , Gaildrat V.
Published: December 2004

Current methods for building models using implicit volume techniques present problems defining accurate and controllable blend shapes between implicit primitives. We present new methods to extend the freedom and controllability of implicit volume modeling. The main idea is to use a free‐form curve to define the profile of the blend region between implicit primitives.

The use of a free‐form implicit curve, controlled point‐by‐point in the Euclidean user space, allows us to group boolean composition operators with sharp transitions or smooth free‐form transitions in a single modeling metaphor. This idea is generalized for the creation, sculpting and manipulation of volume objects, while providing the user with simplicity, controllability and freedom in implicit modeling.

ACM CSS: I.3.5 Computational Gemoetry and Object Modeling—Curve, surface, solid, and object representations
State of the Art in Global Illumination for Interactive Applications and High‐quality Animations
Authors: Damez Cyrille , Dmitriev Kirill , Myszkowski Karol
Published: December 2004

Global illumination algorithms are regarded as computationally intensive. This cost is a practical problem when producing animations or when interactions with complex models are required. Several algorithms have been proposed to address this issue. Roughly, two families of methods can be distinguished. The first one aims at providing interactive feedback for lighting design applications. The second one gives higher priority to the quality of results, and therefore relies on offline computations. Recently, impressive advances have been made in both categories. In this report, we present a survey and classification of the most up‐to‐date of these methods.

ACM CSS: I.3.7 Computer Graphics—Three‐Dimensional Graphics and Realism
The UK and EMU: Lessons from Europe
Authors: Muellbauer John
Published: December 2004

Her Majesty's Treasury is due to report in June 2003 on the economic case for the UK adopting the Euro. One criterion concerns the extent of economic convergence between the UK and the European Union countries. Differences in financial, credit and housing institutions between countries present one important subset of constraints to sustained convergence (Maclennan et al, 1998) ‐ largely neglected in the economic literature on common currency areas. These types of differences create tension within the Eurozone. Empirical evidence supporting these concerns has emerged in signs of overheating in the Netherlands, UK and some of the fringe economies, and in the relative stagnation of Germany and Italy. The UK's buoyancy, however, is accompanied by serious economic imbalances, with consequent risks of instability. These would be exacerbated should the UK be prematurely locked into an exchange rate and interest rate regime unresponsive to domestic conditions. There is much to learn from European experience: from Germany and Italy, on the consequences of illiberal economic structures; from The Netherlands, on some of the risks of liberal credit markets; and from Denmark, with a liberal credit market but rational property taxation. In this paper, John Muellbauer argues that convergence does not have to be fully achieved, if there is a counterbalancing policy instrument to mitigate some of the effects of these slow‐to‐dissipate differences. Specifically in the UK, a reformed system of property taxation would contribute greatly to long‐term stability and the preservation of economic balance.
Retests on the Theory of Collective Action: The Olson and Zeckhauser Model and its Elaboration
Authors: Kwon Gi‐Heon
Published: December 2004

The Olson‐Zeckhauser model explaining contributions to international organizations, which used economic size as the dominant indicator, lost its predictive power by the 1970s. I suggest a broad explanatory factor: contribution incentives experienced by an organization's members. International relations theory enables us to identify systemic reasons why the large industrialized nations might feel less incentive to contribute to international governmental organizations regardless of their policy area. The reasons, changing characteristics of the international system including multipolarity and international economic competition, have intensified since the early 1970s in step with changing contribution patterns. I propose an empirical model, a specific incarnation of the collective‐action framework. This proposed model argues that a state's burden‐sharing reflects the nature of its international preferences, themselves a function of a country's domestic conditions and international incentives. A variety set of tests supports my hypothesis that the decreasing interest of large nations in bankrolling international institutions arises from the increasingly decentralized nature of international influence.
Political Control of Administrative Spending: The Case of Local Governments in Norway
Authors: Kalseth Jorid , Rattsø Jørn
Published: December 2004

Excessive administrative spending in local governments has been a concern in the public debate in Norway. Administration takes resources away from welfare services such as primary education and care for the elderly. Since administrative spending varies considerably between local governments, a study of the political and economic factors involved is warranted. The central hypothesis is that the administrators will have more power relative to the politicians when political control is divided between parties. Estimation of a demand model of administration added political structure shows strong empirical correlations between types of coalition governments and socialist controlled governments and the level of administrative spending. Divided political control strengthens the hands of the agenda setting bureaucrats.
The Institutional Environment for Economic Growth
Authors: Henisz W. J.
Published: December 2004

This article forges an explicit link between an objective measure of political constraints and variation in cross‐national growth rates. It derives a new measure of political constraints from a simple spatial model of political interaction that incorporates information on the number of independent branches of government with veto power and the distribution of preferences across and within those branches. The derived variable is found to have a statistically and economically significant impact on growth rates using simple ordinary least squares, three‐stage least squares and generalized method of moments estimation techniques.
On the Endogenous Choice between Protection and Promotion
Authors: Mitra D.
Published: December 2004

In a model of strategic interaction between firms in lobbying activity, I show that capitalists might prefer tariffs (protection) to production subsidies (promotion). This is due to the congestion problem arising from the government's convex welfare costs of providing subsidies as opposed to both the free‐rider problem and the congestion problem acting in opposite directions in the case of tariffs. If an industry association exists, coordination can be achieved when lobbying for tariffs, but not in the case of production subsidies.
Macroeconomics and Politics Revisited: Do central banks Matter?
Authors: Lossani M. , Natale P. , Tirelli P.
Published: December 2004

This paper provides a model encompassing both partisan influences on monetary policy and the issue of central bank independence. In a regime of partial independence, central bank's policy responses are not immune from partisan influences. Still, the latter fail to affect systematically the expected output level in election years. The predictions of the model are consistent with the empirical literature on partisan cycles and account for some of its controversial findings.
Causality and Feedback Between Institutional Measures and Economic Growth
Authors: Chong A. , Calderón C.
Published: December 2004

Recent cross‐section studies have demonstrated a strong link between measures of corruption, bureaucratic quality, property rights, and other institutional variables, and economic growth. In this paper we build on previous research and present some empirical evidence on the direction of causality between institutional measures and growth. It appears that the poorer the country, and the longer the wait, the higher the influence of institutional quality on economic growth. However, we also show the existence of reverse causality. Indeed, it appears that economic growth also causes institutional quality.
What is Vulnerable During Fiscal Retrenchment?
Authors: Fardmanesh M. , Habibi N.
Published: December 2004

Using data for 70 countries in the 1980s, this study investigates the impact of socioeconomic and political characteristics of a country on the vulnerability of expenditure categories during budget cuts. Greater democracy is associated with less vulnerability of the social and productive sectors and with more vulnerability of the administrative/defense, infrastructure, and miscellaneous sectors. Political instability reduces the vulnerability of the social, administrative/defense, and miscellaneous sectors and increases that of the productive sector. Fiscal federalism increases the vulnerability of the infrastructure and administrative/defense sectors and reduces that of the productive sector. The relative size of the budget cuts is also a determining factor.
Sequencing of Economic Reforms in the Presence of Political Constraints
Authors: Martinelli C. , Tommasi M.
Published: December 2004

This paper presents a model portraying a country in a political deadlock about economic reform proposals in which certain measures hurt strongly‐organized interests. We show that when governments are unable to precommit and interest groups have veto power, only far‐reaching reforms (even if quite costly) have hope of success. The model intends to explain why in recent years several Latin American countries have opted for radical reform.
Employees and second‐job holding in the Federal Republic of Yugoslavia
Authors: Reilly Barry , Krstić Gorana
Published: December 2004

This paper explores the second‐job holding (or ‘moonlighting’) behaviour of a sample of employees using data from a unique survey conducted for the Federal Republic of Yugoslavia (FRY) in January 1998. Both participation in ‘moonlighting’ and the number of hours worked are examined. The participation model performs better in an econometric sense and provides the focus for our discussion. We note a strong regional dimension to ‘moonlighting’ in the FRY with employees in Central Serbia disproportionately represented in this activity. In addition, blue‐collar workers are found to be more likely to engage in ‘moonlighting’ than white‐collar workers. The set of labour supply variables implied by neo‐classical theory exerts a strong influence and explains a significant amount of the phenomenon of interest. Our calculations suggest that if main (or regular) job earnings are restored to levels that prevailed at the time of the ‘break‐up’ of the federation, employee second‐job holding in the FRY would only fall by about one‐seventh.

JEL classification: J21, J22, P2, P3.
Worker flows, job flows and firm wage policies
Authors: Haltiwanger John , Vodopivec Milan
Published: December 2004

Like many transition economies, Slovenia is undergoing profound changes in the workings of the labour market with potentially greater flexibility in terms of both wage and employment adjustment. To investigate the impact of these changes, we use unique longitudinal matched employer‐employee data that permits measurement of employment transitions and wages for workers and enables links of the workers to the firms in which they are employed. We can thus measure worker flows and job flows in a comprehensive and integrated manner. We find a high pace of job flows in Slovenia especially for young, small, private and foreign‐owned firms and for young, less educated workers. While job flows have approached the rates observed in developed market economies, the excess of worker flows above job flows is lower than that observed in market economies. A key factor in the patterns of the worker and job flows is the determination of wages in Slovenia. A base wage schedule provides strict guidelines for minimum wages for different skill categories. However, firms are permitted to offer higher wages to an individual based upon the success of the worker and/or the firm. Our analysis shows that firms deviate from the base wage schedule significantly and that the idiosyncratic wage policies of firms are closely related to the observed pattern of worker and job flows at the firm. Firms with more flexible wages (measured as less compression of wages within the firm) have less employment instability and are also able to improve the match quality of their workers.

JEL Classifications: J23, J31, J41, J61, P23, P31.
Job growth in early transition: Comparing two paths*
Authors: Jurajda Štěpán , Terrell Katherine
Published: December 2004

Small start‐up firms are the engine of job creation in early transition. We ask about differences in their growth across two different transition economies: Estonia, which experienced rapid destruction of pre‐existing firms, and the Czech Republic, which reduced the old sector gradually. We find that the majority of job growth corresponds to within‐industry reallocation. The within‐industry growth of small start‐up firms is similar in the two countries, in line with the convergence to Western industry firm‐size distributions. We also find similar patterns in the evolution of wage differentials between start‐ups and old firms and small differences in the extent of low‐wage employment in start‐ups across the two transition paths.

JEL Classifications: J2, J3, J4, L1, O1, P2.