bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing the Endogenous Ca2+Buffers at the Presynaptic Terminals of the Crayfish Neuromuscular Junction
Authors: Lin Jen-Wei , Fu Qinghao , Allana Tariq
Published: June 2005

Ca2+indicators of varying affinity and mobility were pressure injected into the presynaptic axon of the inhibitor of the crayfish neuromuscular junction (NMJ). Fluorescence transients recorded at a 2-kHz resolution were used to probe physiological parameters governing the decay of fluorescence transients within 100 ms after an action potential (early decay). Blocking Ca2+extrusion or Ca2+sequestration processes did not significantly alter early decay, arguing against a role for either mechanism. Fluorescence transients recorded with low mobility or fixed indicators exhibited early decay similar to that recorded with indicators of comparable affinity but high mobility, suggesting that early decay was not due to the rate of Ca2+-indicator diffusion. The extent of early decay correlated closely with the affinity, but not mobility, of the Ca2+sensitive dyes tested. These results implicate intrinsic buffers with slow Ca2+binding kinetics as the most likely determinants of early decay. However, computer simulations showed that intrinsic buffers with a slow binding rate are unlikely to be the only ones present in the system because the slow kinetics would be unable to buffer incoming Ca2+during an action potential and would result in momentary indicator saturation. In fact, experimental data show that the peak amplitude of an action potential activated Ca2+transient is about 20% of the maximal fluorescence intensity activated by prolonged Ca2+influx. We conclude that endogenous buffering at the crayfish NMJ includes both fast and slow components, the former being fast enough to compete with fast Ca2+indicators, and the latter dictating the early decay.
Elderly Breast Cancer Patients: Adjuvant Chemotherapy and Adjuvant Endocrine Therapy
Authors: Biganzoli Laura , Aapro Matti
Published: June 2005

Older women have unfortunately been underrepresented in breast cancer clinical trials, with the majority of studies being restricted to patients younger than 70 years. Elderly patients are an inhomogeneous group and frequently suffer from comorbidities and/or impaired organ functions. These facts may often lead to death from causes other than cancer, thus nullifying any possible benefit of adjuvant treatment; furthermore, they render extrapolation of standard treatment recommendations to the elderly potentially hazardous, particularly with respect to chemotherapy. Specific clinical trials are therefore needed to investigate adjuvant treatments tailored for the heterogeneous older population.
Substance-P-Mediated Immunomodulation of Tumor Growth in a Murine Model
Authors: Manske Jill M. , Hanson Summer E.
Published: June 2005

Background/Objective: Substance P (SP) has been reported to have immunoregulatory properties including effects on many of the mediators involved in anti-tumor immunity. In this study, we investigated the effect of SP on tumor development in a murine model of melanoma. In addition, we examined the role of natural killer (NK) and T cells in SP-mediated modulation of tumor growth. Materials and Methods: Mice were implanted with mini-osmotic pumps that delivered a continuous infusion of either SP or PBS over a 14-day period. Five days following implantation, animals received K1735 melanoma cells and tumor growth was monitored. The role of NK and T cells in SP-mediated protection was examined by antibody depletion studies. To determine if cells from SP-treated animals could delay tumor growth in animals in the absence of exogenous SP infusion, splenocytes from mice treated with SP were adoptively transferred into SCID mice. Results: In vivoSP treatment led to a significant delay in tumor growth. When animals were depleted of NK or T cells, this protective effect was lost. Adoptive transfer of cells from SP-treated animals led to a significant protective effect on tumor growth in SCID mice. Conclusion: Pretreatment of mice with SP provides protection against K1735 tumor growth, and this protection requires both T cells and NK cells. SP-mediated tumor protection can be transferred by the adoptive transfer of cells from SP-treated animals into animals that do not receive exogenous SP. These studies suggest a model in which in vivo SP treatment prior to tumor challenge primes immune mediators to prevent or delay tumor establishment.
Interleukin-6 and Interleukin-8 Are Elevated in the Cerebrospinal Fluid of Infants Exposed to Chorioamnionitis
Authors: Laborada Gary , Nesin Mirjana
Published: June 2005

Background: The clinical or histologic diagnosis of chorioamnionitis has been associated with an increased risk of neuropathology and adverse neurologic outcomes in premature and term infants. Inflammatory cytokines have been implicated in the pathogenesis of these processes. The objective of this study was to determine whether exposure to chorioamnionitis and fetal inflammatory syndrome is associated with elevated concentrations of inflammatory cytokines (TNF-α, IL-6, and IL-8) in the CSF of term and preterm infants. Methods: Eighty-four mother/infant pairs were studied, 54 infants were premature. Twenty-eight showed signs of maternal (n = 14), or fetal (n = 14) inflammation based on placental pathology; mothers of 24 infants showed signs of clinical chorioamnionitis not confirmed by placental pathology and 32 infants were considered as ‘controls’ since they had only transient difficulty adjusting to extra-uterine life warranting evaluation for sepsis. The cytokine concentrations in the CSF were measured within 24 h of birth. Results: When compared to the control group (IL-8 = 341 ± 170 pg/ml and IL-6 = 7.4 ± 1.8 pg/ml) significantly higher concentrations of IL-8 were detected in the CSF of infants exposed to clinical chorioamnionitis (1,854 ± 878 pg/ml; p = 0.001) and maternal/fetal inflammation (1,754 ± 787 pg/ml; p = 0.001) and of IL-6 in infants with maternal/fetal inflammation (47.6 ± 45.1 pg/ml; p = 0.01). Conclusions: These results indicate that infants exposed to clinical chorioamnionitis, or inflammation in utero, experience at least a transient elevation in inflammatory cytokines in CSF.
Note on New International Case-law Concerning the Binding Character of Provisional Measures
Authors: Kolb Robert
Published: June 2005

Three recent judicial or quasi-judicial cases deal with the question as to if provisional measures indicated by the respective body are binding on the parties to the dispute or not. In all three cases, the constitutive instruments under which the body acted were silent on the question of the binding nature of the measures at stake. Traditionally, the point as to the bindingness of such measures, in the absence of any special provision granting them a binding force, was extremely controversial. Now, through these three recent cases, the jurisprudence forcefully affirmed such bindingness. The reasoning on which the three cases are based is similar: according to the caselaw, teleological reasons compel to consider that the provisional measures indicated are binding, since to hold otherwise would allow one party to frustrate the object and purpose of the whole proceeding while the matter is pending. It may thus well be that these three recent precedents established a new (procedural) customary presumption, by a sort of quick speed customary law. Thus, in the absence of special provision to the contrary, provisional measures indicated by an international judicial or quasi-judicial body would be binding, at least when such measures are taken in order to safeguard the respective rights of the parties.
The Nationality of Denationalized Palestinians
Authors: Kattan Victor
Published: June 2005

One in three refugees in the world today is Palestinian. The majority of these refugees have no nationality because they were denationalised by Israel's Nationality Law in 1952 after they had fled or been expelled from their homeland in 1948. Israel has refused to allow the majority Palestinian refugees, being displaced in 1948, the right to return to their homes in contravention of U.N. General Assembly Resolution 194 (III). Israel has also refused to allow the majority of Palestinians displaced in 1967 the right to return to their homes despite appeals from the International Committee of the Red Cross and despite calls from the UN Security Council. Since then Israel has manipulated the laws of occupation by transferring its civilian population into the territory it occupies whilst subjecting the indigenous Palestinian population to military law. In 2003, Israel enacted racially discriminatory legislation in the form of the Nationality and Entrance into Israel Law which the U.N. Human Rights Committee has specifically requested Israel revoke. This legislation restricts nationality and residency rights for Arabs resident in the Occupied Palestinian Territories whilst specifically excluding Jewish settlers from its application. These are some examples of the lengths to which the State of Israel is prepared to go – in order to maintain a Jewish majority in the country – even if they violate international law. This paper will examine whether the forced displacement and denationalization of Palestine's original non-Jewish inhabitants – including an examination of Israel's Nationality and Entrance into Israel Law (2003) – are compatible with the basic principles of international law today.
Addressing Norm Conflicts in a Fragmented Legal System: The Doctrine of Lex Specialis
Authors: Lindroos Anja
Published: June 2005

The increased fragmentation of international law has been accompanied by a more problematic phenomenon: institutional fragmentation that has strengthened the role of specialised regimes (e. g., WTO, EU, human rights and environmental regimes) within the international legal system. "The emergence of seemingly independent subregimes has given rise to a number of legal concerns – among these is the existence of normative conflicts between regimes." In a recent report by the Chairman of the ILC Study Group on Fragmentation of International Law, Martti Koskenniemi, dealt with the role of the lex specialis maxim as a means of addressing the relation between selfcontained regimes and general international law. This article argues that an application of lex specialis, although widely accepted, is impeded by its conceptual vagueness. Lex specialis may be well-suited to resolve certain types of normative conflicts, such as conflicts within sub-regimes, which may be viewed as a more traditional manifestation of normative conflicts. The fragmentation of international law, however, has also created new types of conflicts, namely those between different, seemingly independent normative orders. The article suggests that the lex specialis maxim is a less-suitable approach to normative conflicts between such unrelated normative orders. In a fragmented legal system such as that of international law, these types of conflicts may, accordingly, prove a particular challenge.
Melodies on Comparative Law: A Review Essay
Authors: Husa Jaakko
Published: June 2005

The volume under review contains theoretical reflections on comparative law dealing with diverse topics ranging from the basis of the discipline to globalization, Europeanization and transposition of law. According to the author of the book, comparative law is a subject that can be approached solely as an enigma and the book aims to do this with the help of metaphors taken from the theory of music. This volume expresses a complex understanding of comparative law and shakes off the old images of comparative law as being either a purely academic or a hopelessly non-theoretical practical exercise. The Enigma of Comparative Law is different in orientation both to the scholarship of conventional comparative law and to post-modern/critical comparative law which have argued for extreme all-or-nothing positions. The political nature of comparative law venture is openly acknowledged but it is not seen as overwhelming. Esin Örücu's book also argues for legal pluralism and a comprehensive view of law. The book applauds methodological pluralism. Diversity of methods is seen not as being counterproductive but instead as a virtue that will enhance the future prospects of comparative law in internationalized world. The review essay concludes by arguing for an idea according to which there is no one legitimate tradition of comparative law/comparative legal studies but many.
Ecosystem Structure throughout the Brazilian Amazon from Landsat Observations and Automated Spectral Unmixing
Authors: Asner Gregory P. , Knapp David E. , Cooper Amanda N. , Bustamante Mercedes M. C. , Olander Lydia P.
Published: June 2005

The Brazilian Amazon forest and cerrado savanna encompasses a region of enormous ecological, climatic, and land-use variation. Satellite remote sensing is the only tractable means to measure the biophysical attributes of vegetation throughout this region, but coarse-resolution sensors cannot resolve the details of forest structure and land-cover change deemed critical to many land-use, ecological, and conservation-oriented studies. The Carnegie Landsat Analysis System (CLAS) was developed for studies of forest and savanna structural attributes using widely available Landsat Enhanced Thematic Mapper Plus (ETM+) satellite data and advanced methods in automated spectral mixture analysis. The methodology of the CLAS approach is presented along with a study of its sensitivity to atmospheric correction errors. CLAS is then applied to a mosaic of Landsat images spanning the years 1999–2001 as a proof of concept and capability for large-scale, very high resolution mapping of the Amazon and bordering cerrado savanna. A total of 197 images were analyzed for fractional photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and bare substrate covers using a probabilistic spectral mixture model. Results from areas without significant land use, clouds, cloud shadows, and water bodies were compiled by the Brazilian state and vegetation class to understand the baseline structural typology of forests and savannas using this new system. Conversion of the satellite-derived PV data to woody canopy gap fraction was made to highlight major differences by vegetation and ecosystem classes. The results indicate important differences in fractional photosynthetic cover and canopy gap fraction that can now be accounted for in future studies of land-cover change, ecological variability, and biogeochemical processes across the Amazon and bordering cerrado regions of Brazil.
Veto Points, Veto Players, and International Trade Policy
Authors: O’Reilly Robert F.
Published: June 2005

Much of the literature on foreign economic policy focuses on the preferences of societal groups to explain policy decisions. Here, however, the author emphasizes the effects of domestic political institutions that intervene between policy demands and policy decisions. The comparative politics literature on social welfare policy argues that states with more veto points and/or veto players are less able to alter preexisting policies. The author applies this argument to trade policy and tests whether veto points and players affect the ability of states to change tariffs and nontariff barriers in response to changing economic conditions. The sample is a cross-national time-series collection of 23 countries. The results offer support for the argument. Large numbers of institutional veto points are associated with smaller percentage changes in both tariffs and nontariff barriers. These relationships hold even after controlling for the effects of international institutions and for domestic pressures to change tariff and nontariff-barrier levels.
Social Protection Around the World
Authors: Mares Isabela
Published: June 2005

This article develops and tests a political model specifying the conditions under which external risk leads to the introduction of redistributive social policies and argues that external risk sharpens a domestic political cleavage over the design of institutions of social insurance. Workers in sectors facing high volatility of income will support the introduction of social policies characterized by broad levels of insurance coverage and high redistribution of costs across occupations, whereas workers in low-risk sectors will oppose redistributive social policies. The strength of preexisting state institutions also affects policy preferences of various sectors. In the presence of weak, ineffective states that are unable to collect social insurance contributions from sectors that are net contributors to the system, high-risk sectors will find redistributive social policies unattractive. The article tests predictions of the model using new measures of the level of social insurance coverage in more than 100 countries.
Buying Out the State
Authors: Schneider Volker , Fink Simon , Tenbücken Marc
Published: June 2005

The article describes the retreat of the state from public infrastructures in advanced industrial countries and tests the power of theoretical approaches to explain this reform process. The authors’ data show changes in state ownership in formerly public monopoly enterprises in telecommunications, electricity, and aviation sectors of 26 countries between 1970 and 2000. Combining various analytical techniques, the authors use partial-order scalogram analysis to visualize the similarity of institutional structures and country-specific development trajectories. By pooled time-series regression they show that only the liberalization of capital markets has a significant effect on infrastructure privatization. The effects of party ideology, veto players, or corporatist interest group systems are rather insignificant over the whole period. However, by an innovative use of yearly ordinary least squares regressions, they show that governmental ideology holds great predictive power for privatization in the 1980s but not for the 1990s, when almost all countries had privatized.
The Politics of Territorial Solidarity
Authors: Béland Daniel , Lecours André
Published: June 2005

Despite the recent proliferation of literature on nationalism and on social policy, little has been written to explore the possible interaction between the two. This article explores two essential aspects of the relationship between substate nationalism and welfare-state development in Canada (Québec), the United Kingdom (Scotland), and Belgium (Flanders). First, the article shows how the processes of identity formation/consolidation and territorial mobilization inherent to substate nationalism often involve a social policy dimension. Second, it analyzes the ways in which substate nationalism has affected welfare-state development in recent decades. Substate nationalism can impact social policy making in at least two ways: by reshaping the policy agenda at both the state and the substate levels and by reinforcing regional policy autonomy, which is depicted as an alternative to centralist schemes. To explain significant variations between the three empirical cases, the article underlines specific institutional, ideological, and socioeconomic factors.
Resurgence and Remaking of Identity
Authors: Somer Murat
Published: June 2005

This article analyzes the case of Turkey and theorizes about the causal mechanisms that can explain discursive transformations through which dominant perceptions of ethnic identities are suppressed, revived, and remade. Systematic content analysis of a major Turkish newspaper from 1984 through 1998, comparisons across subperiods, in-depth interviews with prominent journalists, and detailed examination of the historical events constitute the empirical analysis. Arguing that the state elites did not form a monolithic group, it is shown that the transformation of the mainstream discourse during the 1990s occurred after several reversals, relatively swiftly, and at least partly despite resistance from with in the state. The Kurdistan Worker’s Party conflict; shifting instrumental elite beliefs; breakdown of cooperation among moderates; external developments, including those in Iraq; and cascade mechanisms played causal roles. The explanation contributes to a multidisciplinary body of literatures on public-political discourse, cascade theories of social-political change, ethnic conflict, democratization, Turkey, and Kurds and derives policy implications.
The Intragroup Stigmatization of Skin Tone Among Black Americans
Authors: Harvey Richard D. , LaBeach Nicole , Pridgen Ellie , Gocial Tammy M.
Published: June 2005

The purpose of this study was to examine the extent to which racial contexts moderate the importance and function of intragroup skin-tone stigma among Black Americans. One hundred and thirty-two Black students were recruited from both a predominantly Black university and a predominantly White university and completed measures on skin tone, skin-tone importance, peer-group acceptance, self-esteem, and racial identification. The authors found that Black students in the predominantly Black university placed significantly higher importance on skin tone than Black students in the predominantly White university. Furthermore, both higher perceived peer acceptance and higher self-esteem were correlated with darker skin tone at the Black university but not at the White university. However, stronger racial identity was equally correlated with darker skin tone in both contexts. The results of this study suggest that the importance of skin tone is moderated by racial context.
Examining Mainstream and Afro-Cultural Value Socialization in African American Households
Authors: Tyler Kenneth M. , Boykin A. Wade , Boelter Christina M. , Dillihunt Monica L.
Published: June 2005

This article examines the role of culture in the socialization patterns found in the households of low-income African Americans. Using the Triple Quandary theoretical framework, the authors hypothesized that cultural themes consistent with an Afro-cultural ethos would be reported significantly more than those associated with a mainstream cultural ethos. Scenarios depicting socialization activities reflecting the four distinct cultural themes were constructed. Seventy-one low-income African American parents reported how often they perform the activities reflecting the cultural themes in question. Findings revealed that parents reported communal practices significantly more than those activities linked to the remaining three cultural themes. Implications and future research directions are discussed.
Relationship of Distress and Perceived Control to Coping With Perceived Racial Discrimination Among Black Youth
Authors: Scott Lionel D. , House Laura E.
Published: June 2005

This study examines the use of approach (e.g., seeking social support, problem solving) and avoidance (e.g., distancing, internalizing, externalizing) strategies for coping with perceived racial discrimination and their relationship to the subjective feelings of distress evoked by perceived experiences of discrimination and perceived control over discriminatory experiences among a small, relatively homogeneous sample of Black youth (N = 71). Results of hierarchical regression analyses support evidence from the general adolescent stress and coping literature that links avoidance coping to greater feelings of distress and approach coping to a greater sense of personal control. Greater self-reports of distress are related to greater use of internalizing and externalizing coping strategies. Greater self-reports of perceived control over discriminatory experiences are related to greater use of seeking social support and problem-solving coping strategies. Implications for promoting the successful coping of Black youth with perceived racial discrimination are discussed.
Studies on Poly(Styrene-co-Butyl Acrylate) Latex-reinforced Polyester Nonwoven Fabric Thermoplastic Composites
Authors: Kumar M. N. Satheesh , Siddaramaiah
Published: June 2005

A series of thermoplastic composites have been fabricated by impregnating polyester nonwoven fabric in poly(styrene-co-butyl acrylate) latex having different monomer ratios of styreneto-butyl acrylate viz., 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 weight by weight. The latex-based matrix of poly(styrene-co-butyl acrylate) has been prepared using the conventional emulsion polymerization technique. The fabricated composites have been studied for physicomechanical properties, chemical resistance, percentage of water absorption, and percentage of thickness swelling. The prepared composites have been investigated for their ability to retain their shape after molding to the desired shape by measuring the percentage area shape retention, hardness, and resilience.
Compression Strength of Saline Water-exposed Epoxy System Containing Fly Ash Particles
Authors: Kishore  , Barpanda P. , Kulkarni S. M.
Published: June 2005

Epoxy systems with and without different volume fractions of fly ash particulate fillers are made and their absorption due to immersion in saline water maintained at room temperature are established through weight measurements recorded up to 100 h. The 100-h exposed samples are additionally subjected to compression tests to evaluate the strength. The results show that both neat epoxy and fly ash-bearing composites exhibit differing levels of aqueous medium absorption – it being less in ash-free samples. When the ash content in the system is large, the absorption levels are high. The data further revealed that the unexposed samples generally record an increasing strength value with ash content. However, for the exposed cases, a reversal in trend with the ash content is noticed. Attempts to explain these differing trends are made in this work by analyzing the features observed on the surface of compression-failed samples using fractography employing scanning electron microscopy (SEM).
The Emerging Roles of County Governments in Metropolitan and Nonmetropolitan Areas: Findings From a National Survey
Authors: Lobao Linda , Kraybill David S.
Published: June 2005

During the past few decades, local governments have extended the scope of their activities in response to changing economic and political conditions. By and large, research on local governments neglects counties, now the fastest growing general-purpose governments. This article examines counties’roles in economic development and public service activities and reports on findings from a national survey of county governments with broad generalizability and a relatively high response rate across metropolitan and nonmetropolitan areas. Counties provide important services that promote local economic development, enhance human capital, and serve social safety net functions. In accordance with literature on decentralization, the scope of these activities is reported to have grown with the passage of time. Relative to other counties, however, nonmetro counties provide fewer economic development and other public services and are less likely to have increased their role in these activities over time. The article examines reasons for these metro-nonmetro differences.
Discourse and Resistance
Authors: Putnam Linda L. , Grant David , Michelson Grant , Cutcher Leanne
Published: June 2005

This article highlights the contributions that discourse analysis can make to the study of organizational resistance. Specifically, it demonstrates how using a discursive lens can provide insights into the targets, practices, and consequences of resistance. First, discourse analytic approaches can reveal how acts of resistance target multiple organizational audiences simultaneously, often developed through diverse texts directed to internal and external stakeholders. Second, discourse analysis enables researchers to examine the complex, dynamic, and interconnected nature of resistance practices and to avoid constructing simple dichotomies between such features as covert and overt forms of resistance or individual and collective resistance. Third, discourse analysis highlights the intended and unintended consequences of resistance by examining how organizational members engage with, adapt to, and transform organizational practices. Future directions are proposed for research on discourse analysis and organizational resistance.
Theorizing Resistance in Organization Studies
Authors: Mumby Dennis K.
Published: June 2005

This article provides an overview and critique of the extant research on work-place resistance. It argues that much of this research has developed around an implicit duality of resistance and control. In other words, critical studies have highlighted either the growing ubiquity and subtlety of managerial control or have privileged workers’ abilities to carve out spheres of autonomy within these control mechanisms. It suggests that, in contrast to this implicit dualism of control and resistance, a dialectical approach better captures the notion of resistance and control as mutually constitutive, and as a routine social production of daily organizational life.
Metaphors of Resistance
Authors: Fleming Peter
Published: June 2005

Research exploring corporate culture management has identified cynicism as a significant way some workers resist attempts to control their identities. The metaphors of defense and distancing are popular ways of explaining this cynicism. The article argues that these metaphors posit an already-present self as the object of protection. Drawing on empirical research of a communications firm, it is suggested cynicism might also be understood as the on going production of subjectivity rather than its defense or distancing from cultural controls.
Resistance Through Consent?
Authors: Ashcraft Karen Lee
Published: June 2005

Recent theories underscore the indefinite, conflicted, and discursive character of labor identity and resistance, highlighting local practices and meanings. This article examines an empirical and political dilemma provoked by such models: what to do when once-dominant voices resist a loss of control. Drawing on interviews conducted with commercial airline pilots, the author examines how privileged professional men engage gendered threats. The analysis demonstrates how organizational efforts to induce crew empowerment threaten pilot identity, as well as how pilots resist emasculation by embracing mandatory changes. The study illustrates ways to grapple more fully with the implications of discursive, dialectical models of resistance. In particular, the author urges attention to tales of declining control as discursive realities that engender emotional resistance to social change.
Ironies in the Discursive Struggle of Pilots Defending the Profession
Authors: Real Kevin , Putnam Linda L.
Published: June 2005

This article examines discursive forms of resistance used by a splinter group of a U.S. airline pilots’ union in its campaign against a contract settlement supported by union leaders. Forms of resistance included oppositional tensions, military metaphors, and dualities that surfaced in central themes of the campaign. These discursive strategies revealed ironies of advocating unity while promoting division and arguing to eliminate a two-tiered pay scale while supporting class distinctions between pilots. These tactics were similar to and different from approaches that oppositional groups within conventional unions typically used. Overall, these strategies pitted pilots against pilots, professionals against professionals, union against union and suggested that organized resistance is constructed discursively, ironically and in tandem with routine resistance practices.
Online Consultation
Authors: Ainsworth Susan , Hardy Cynthia , Harley Bill
Published: June 2005

To explore the implications of the Internet for the relationship between organizational communication and power, this article compares two online forums established in response to the introduction of a new e-organization: the Development Gateway. The article analyzes postings to the forums to explore the capacity of the Internet to foster democracy, and to investigate how power and resistance are exercised through this medium. Findings show that, rather than equate resistance with participation, as some models of democracy do, the dynamics of power and resistance are more complex, and resistance and power can take participative and nonparticipative forms.!
The hydroxyurea-induced small GTP-binding protein SAR modulates γ-globin gene expression in human erythroid cells
Authors: Tang Delia C. , Zhu Jianqiong , Liu Wenli , Chin Kyung , Sun Jun , Chen Ling , Hanover John A. , Rodgers Griffin P.
Published: June 2005

Hydroxyurea (HU), a drug effective in the treatment of sickle cell disease, is thought to indirectly promote fetal hemoglobin (Hb F) production by perturbing the maturation of erythroid precursors. The molecular mechanisms involved in HU-mediated regulation of γ-globin expression are currently unclear. We identified an HU-induced small guanosine triphosphate (GTP)–binding protein, secretion-associated and RAS-related (SAR) protein, in adult erythroid cells using differential display. Stable SAR expression in K562 cells increased γ-globin mRNA expression and resulted in macrocytosis. The cells appeared immature. SAR-mediated induction of γ-globin also inhibited K562 cell growth by causing arrest in G1/S, apoptosis, and delay of maturation, cellular changes consistent with the previously known effects of HU on erythroid cells. SAR also enhanced both γ- and β-globin transcription in primary bone marrow CD34+ cells, with a greater effect on γ-globin than on β-globin. Although up-regulation of GATA-2 and p21 was observed both in SAR-expressing cells and HU-treated K562 cells, phosphatidylinositol 3 (PI3) kinase and phosphorylated ERK were inhibited specifically in SAR-expressing cells. These data reveal a novel role of SAR distinct from its previously known protein-trafficking function. We suggest that SAR may participate in both erythroid cell growth and γ-globin production by regulating PI3 kinase/extracellular protein–related kinase (ERK) and GATA-2/p21-dependent signal transduction pathways.
Theme discovery from gene lists for identification and viewing of multiple functional groups
Authors: Pehkonen Petri , Wong Garry , Törönen Petri
Published: June 2005

Background

High throughput methods of the genome era produce vast amounts of data in the form of gene lists. These lists are large and difficult to interpret without advanced computational or bioinformatic tools. Most existing methods analyse a gene list as a single entity although it is comprised of multiple gene groups associated with separate biological functions. Therefore it is imperative to define and visualize gene groups with unique functionality within gene lists.

Results

In order to analyse the functional heterogeneity within a gene list, we have developed a method that clusters genes to groups with homogenous functionalities. The method uses Non-negative Matrix Factorization (NMF) to create several clustering results with varying numbers of clusters. The obtained clustering results are combined into a simple graphical presentation showing the functional groups over-represented in the analyzed gene list. We demonstrate its performance on two data sets and show results that improve upon existing methods. The comparison also shows that our method creates a more simplified view that aids in discovery of biological themes within the list and discards less informative classes from the results.

Conclusion

The presented method and associated software are useful for the identification and interpretation of biological functions associated with gene lists and are especially useful for the analysis of large lists.
Genetic structure in four West African population groups
Authors: Adeyemo Adebowale A , Chen Guanjie , Chen Yuanxiu , Rotimi Charles
Published: June 2005

Background

Africa contains the most genetically divergent group of continental populations and several studies have reported that African populations show a high degree of population stratification. In this regard, it is important to investigate the potential for population genetic structure or stratification in genetic epidemiology studies involving multiple African populations. The presences of genetic sub-structure, if not properly accounted for, have been reported to lead to spurious association between a putative risk allele and a disease. Within the context of the Africa America Diabetes Mellitus (AADM) Study (a genetic epidemiologic study of type 2 diabetes mellitus in West Africa), we have investigated population structure or stratification in four ethnic groups in two countries (Akan and Gaa-Adangbe from Ghana, Yoruba and Igbo from Nigeria) using data from 372 autosomal microsatellite loci typed in 493 unrelated persons (986 chromosomes).

Results

There was no significant population genetic structure in the overall sample. The smallest probability is associated with an inferred cluster of 1 and little of the posterior probability is associated with a higher number of inferred clusters. The distribution of members of the sample to inferred clusters is consistent with this finding; roughly the same proportion of individuals from each group is assigned to each cluster with little variation between the ethnic groups. Analysis of molecular variance (AMOVA) showed that the between-population component of genetic variance is less than 0.1% in contrast to 99.91% for the within population component. Pair-wise genetic distances between the four ethnic groups were also very similar. Nonetheless, the small between-population genetic variance was sufficient to distinguish the two Ghanaian groups from the two Nigerian groups.

Conclusion

There was little evidence for significant population substructure in the four major West African ethnic groups represented in the AADM study sample. Ethnicity apparently did not introduce differential allele frequencies that may affect analysis and interpretation of linkage and association studies. These findings, although not entirely surprising given the geographical proximity of these groups, provide important insights into the genetic relationships between the ethnic groups studied and confirm previous results that showed close genetic relationship between most studied West African groups.
Linking changes in atmospheric dust deposition, vegetation change and human activities in northwest Spain during the last 5300 years
Authors: Cortizas A. Martinez , Mighall T. , Pombal X. Pontevedra , Munfoz J. C. Novoa , Varelal E. Peiteado , Rebolol R. Pifneiro
Published: June 2005

A high-resolution, 5300-yr record of pollen and lithogenic elements (K, Ca, Ti, Rb, Sr, Y, Zr) from an ombrotrophic peat bog located in northwest Spain, reveals that the variations in the fluxes of lithogenic elements supplied to the bog by atmospheric deposition were coupled to the evolution of the vegetation of the area. A strong negative correlation exists between the percentage of tree pollen and the concentration of lithogenic elements. For example, the correlation between total tree pollen and Sr concentrations is - 0.94. The main phases of decline of the deciduous forest occurred during known cultural periods (late Neolithic, the Metal Ages, the Roman Period, the Middle Ages and the Industrial period) suggesting a close link between human activities (fires and forest clearances), changes in the vegetation and soil erosion. The flux of lithogenic elements seems to have increased before a significant variation in pollen is detected, which may indicate that changes in soil erosion are reflected earlier than the changes in vegetation in the bog record. Variations in the composition of the deposited dust reflect impacts that occurred at different spatial scales, with local sources dominant in the late Neolithic, the Metal Ages and the Middle Ages, whilst regional sources are more important in the Roman period and the Industrial Revolution. During the prehistoric period, arboreal pollen percentages recovered to their former levels, suggesting that woodland regenerated following a disturbance phase, but for the last 1400 years no significant recovery took place until afforestation with pines was introduced 200 years ago. While this must be the result of continuous clearances to convert forest into arable land, a cumulative effect on soil degradation must also be implied.
Climate change and human settlement as drivers of late-Holocene vegetational change in the Faroe Islands
Authors: Hannon Gina E. , Bradshaw Richard H. W. , Bradshaw Emily G. , Snowball Ian , Wastegård Stefan
Published: June 2005

Changes in Faroese land surfaces during the late Holocene reflect intimate interactions between cultural and environmental development. Analyses of fossil wood, pollen and plant macrofossils indicate that the present open landscape replaced shrubby vegetation that was present from c. 6000 BC Up to C. AD 660. Conditions altered during the late Holocene, with loss of woody vegetation and increasing erosion: trends that were initiated prior to human settlement. AMS dating of sub-fossil Betula, Salix and Juniperus found buried in peat profiles from the islands of Su8uroy, Sandoy, Eysturoy, Vagar and Streymoy, revealed that the islands had at least partial woody vegetation cover up to the time of continuous settlement. The settlement horizon, identified in a lacustrine sequence on the island of Eysturoy, dated to c. AD 570. It comprised pollen evidence for the cultivation of Hordeum, cultural macrofossil assemblages, charcoal fragments, diatom assemblage changes indicating lake nutrient enrichment and physical measurements showing increased sedimentation rates. The pollen record showed that heathland development was initiated prior to anthropogenic impact. The ecosystem impacts of settlement were therefore superimposed on landscape changes that began around AD 250. The earlier changes were most likely forced by increased storminess and declining atmospheric temperatures.
Correspondence of pollen assemblages with forest zones across steep environmental gradients, Olympic Peninsula, Washington, USA
Authors: Gavin Daniel G. , Brubaker Linda B. , McLachlan Jason S. , Oswald W. Wyatt
Published: June 2005

The use of pollen records to document vegetation responses to climatic change in mountains relies on the ability of pollen assemblages to differentiate among elevationally stratified vegetation zones. Comparisons among modem pollen assemblages within mountainous areas provide a basis for assessing this potential. We examined relationships between pollen assemblages, forest vegetation and climate at 65 small lake sites distributed across five forest zones on the Olympic Peninsula, Washington. Sample sites spanned nearly the full range of climatic gradients on the Peninsula, c. 900-6000 mm annual precipitation and c. 17-8C July mean temperature (from 9 to 1981 m a.s.l.). The pollen percentages of most arboreal taxa showed a strong relationship with elevation, especially for taxa with poor dispersal potential (Abies and Picea) or high elevation ranges (Tsuga mertensiana and Alnus sinuata). Tsuga heterophylla was the only pollen taxon abundant across all forest zones. Both detrended correspondence analysis (DCA) and linear discriminant analysis (DA) arranged pollen assemblages along temperature and precipitation gradients approximating the actual distribution of vegetation along these gradients. DA classified 90% of the sites into their correct forest zones, but was very sensitive to sample size, suggesting that caution should be exercised when using DA for classifying fossil pollen assemblages. Pairwise comparisons using the squared-chord-distance metric (SCD) showed that the SCD threshold that best distinguishes neighbouring forest zones is affected by the number of samples in each forest zone and by the patchiness of species distributions within each zone, suggesting that SCD is also sensitive to sample size and that thresholds used with the modem analogue technique must be calibrated for each vegetation zone. This study indicates that pollen assemblages on the Olympic Peninsula record local forest zones despite steep environmental gradients and the close proximity of neighbouring forest zones.
Pollen and plant macrofossil analyses of radiocarbon dated mid-Holocene profiles from two subalpine lakes in the Rila Mountains, Bulgaria
Authors: Tonkov Spassimir , Marinova Elena
Published: June 2005

Pollen analysis, plant macrofossil determination and radiocarbon dating were performed on profiles of Holocene age obtained from two subalpine lakes (2320-2340 m a.s.l.) in the Central Rila Mountains, Bulgaria. The palaeovegetational reconstruction dates back to the mid-Atlantic (6500-6700 cal. BP). The plant macrofossil record revealed that groups of Pinus mugo and Juniperus sibirica were distributed in the subalpine zone. The treeline was shaped by Pinus sylvestris and Pinus peuce and was higher (up to 2200-2300 m a.s.l.) compared with the present-day. A change to cooler summers and warmer winters after 6700 cal. BP, characterized by a rise in humidity and precipitation, stimulated the formation of a coniferous vegetation belt dominated by Pinus sylvestris, Pinus peuce and Abies alba. The pollen assemblages also indicated a dominance of deciduous trees (Quercetum mixtum-Corylus phase) at low altitudes until c. 6000 cal. BP. The sub-Boreal was characterized by a wider distribution of Abies alba in the lower part of the coniferous belt and a gradual enlargement of the areas occupied by Fagus sylvatica and Picea abies after 3800-3500 cal. BP. The macrofossil finds of Picea abies testify to its expansion after 2800 cal. BP when average temperatures dropped and precipitation increased. Traces of human disturbance in the subalpine area are continuously registered in the pollen and plant macrofossil records since 3770 cal. BP, indicating livestock-grazing, burning of dwarf-pine (Pinus mugo) for new pasture land and lowering of the treeline.
Early-Holocene afforestation processes in the lower subalpine belt of the Central Swiss Alps as inferred from macrofossil and pollen records
Authors: Gobet Erika , Tinner Willy , Bigler Christian , Hochuli Peter A. , Ammann Brigitta
Published: June 2005

To reconstruct the vegetation history of the Upper Engadine, continuous sediment cores covering the past 11 800 years from Lej da Champfer and Lej da San Murezzan (Upper Engadine Valley, c. 1800 m a.s.l., southeastern Switzerland) have been analysed for pollen and plant macrofossils. The chronologies of the cores are based on 16 and 22 radiocarbon dates, respectively. The palaeobotanical records of both lakes are in agreement for the Holocene, but remarkable differences exist between the sites during the period 11 100 to 10 500 cal. BP, when Lej da Champfer was affected by re-sedimentation processes. Macrofossil data suggest that Holocene afforestation began at around 11400 cal. BP. A climatic deterioration, the Preboreal Oscillation, stopped and subsequently delayed the establishment of trees until c. 11000 cal. BP, when first Betula, then Pinus sylvestrislmugo, then Larix 300 years later, and finally Pinus cembra expanded within the lake catchment. Treeline was at c. 1500 m during the Younger Dryas (12 542- 11 550 cal. BP) in the Central Alps. Our results, along with other macrofossil studies from the Alps, suggest a nearly simultaneous afforestation (e.g., by Pinus sylvestris in the lower subalpine belt) between 1500 and 2340 m a.s.l. at around 11 400 to 11 300 cal. BP. We suggest that forest-limit species (e.g., Pinus cembra, Larix decidua) could expand faster at today's treeline (c. 2350 m a.s.l.), than 550 m lower. Earlier expansions at higher altitudes probably resulted from reduced competition with low-altitude trees (e.g. Pinus sylvestris) and herbaceous species. Comparison with other proxies such as oxygen isotopes, residual A14C, glacier fluctuations, and alpine climatic cooling phases suggests climatic sensitivity of vegetation during the early Holocene.