bluuebunny/crossref_metadata_2025 huggingface dataset:
The modulation of endothelial cell gene expression by green tea polyphenol‐EGCG
Authors: Liu Liping , Lai Chao‐Qiang , Nie Lin , Ordovas Jose , Band Michael , Moser Leta , Meydani Mohsen
Published: May 2008

Human and animal studies have shown that green tea consumption is associated with a reduced risk of some cancers. This has been attributed to its polyphenol components, in particular (–)‐epigallocatechin gallate (EGCG). In addition to be a cancer chemopreventive agent, EGCG inhibits angiogenesis, thus reducing tumor growth and metastasis. We tested EGCG modulation on the gene expression profile of endothelial cells stimulated by VEGF using Affymetrix microarrays. A total of 421 genes were up‐regulated and 72 genes were down‐regulated at the false discovery rate of 5% by VEGF, EGCG, and EGCG pretreatment followed by VEGF stimulation. The changes in the expression of several pivotal genes were validated by real‐time PCR. Furthermore, we have identified two signaling pathways (Wnt and Id) involved in cell proliferation were inhibited by EGCG treatment, suggesting the negative regulation of EGCG on cell proliferation. Our results also indicate that the antiangiogenesis effect of EGCG is partially mediated through its broad inhibition on endothelial cell proliferation. Our data further support earlier observations that the anticancer effect of EGCG is mediated through changes in the expression of genes that are associated with cell proliferation.
A pilot study of a pulmonary rehabilitation programme evaluated by four adults with chronic obstructive pulmonary disease
Authors: Norweg Anna , Bose Pia , Snow Gloria , Berkowitz Monique E.
Published: May 2008

The purpose of this qualitative study was to analyse participants' perceptions of a pulmonary rehabilitation programme, which combined occupational therapy with physical therapy. Semi‐structured interviews were used to collect data from four adults with chronic obstructive pulmonary disease (COPD) who attended an outpatient pulmonary rehabilitation programme in New York City. Features of the occupational therapy programme reported to be valuable were biofeedback and clinician support. Participants reported more control of dyspnoea, improved mental health and confidence in performing daily activities, less fatigue, more physically active lifestyles and hope for the future. Limitations of the study were that participants were interviewed only once and themes were not verified with participants. The study results also cannot be generalized. Further research is needed to evaluate the effectiveness of occupational therapy in promoting self‐management and coping skills and restoring occupational performance in adults with COPD. Participants' responses provide additional support for developing cognitive‐behavioural protocols in occupational therapy and measuring their effectiveness in relieving anxiety symptoms and promoting dyspnoea management. Copyright © 2008 John Wiley & Sons, Ltd.
Continuity and change in Argentine interest group activity and lobbying practices
Authors: Johnson Diane E.
Published: May 2008

For much of Argentina's history, key groups representing labour, big business and agriculture went directly to the executive branch rather than working through the relatively weak national Congress or political parties. Political instability both contributed to, and resulted from, this tendency. Since the return to democracy in 1983, the process of interest articulation has manifested both continuity and change. Although the system remains distinct from the traditional models of pluralism and corporatism in the U.S. and Western Europe, the adoption of ‘neoliberal’ economic policies and the gradual institutionalization of democracy have led to an incremental but, as yet, incomplete shift from a form of corporatism to one that is more pluralistic. While neither globalization nor pluralism guarantee democratic stability, the resultant changes in these contexts are likely to be more conducive to democratic stability and government accountability in Argentina than the old system of interest articulation. However, Argentina has no general law regulating lobbying practices, despite efforts to pass one in the recent years.

Copyright © 2008 John Wiley & Sons, Ltd.
Wnt10b induces chemotaxis of osteosarcoma and correlates with reduced survival
Authors: Chen Kevin , Fallen Shannon , Abaan Hatice Özel , Hayran Mutlu , Gonzalez Corina , Wodajo Felasfa , MacDonald Tobey , Toretsky Jeffrey A. , Üren Aykut
Published: May 2008

Background

Osteosarcoma (OS) is a primary malignant tumor of the bone that typically presents in the second decade of life and has a poor prognosis, especially in metastatic cases. Wnt signaling contributes to the pathogenesis of tumors such as colon cancer and malignant melanoma. Wnt signaling controls normal bone formation during embryogenesis and homeostasis in adult organisms, thus we evaluated Wnt signaling in OS.

Procedure

We surveyed the expression of Wnts, their receptors, Frizzleds and LRPs, and soluble Wnt inhibitors (sFRPs) in four OS cell lines by RT‐PCR. We also tested biological response of OS cell lines to exogenous Wnts by measuring β‐catenin stabilization, Dvl phosphorylation, TOPFLASH activity and chemotaxis. Human OS tumor microarrays were evaluated for expression of Wnt10b by immunohistochemistry.

Results

All cell lines tested showed expression of at least three Wnts and one Frizzled. Exogenous Wnt3a and Wnt10b treatment induced Dvl phosphorylation, β‐catenin stabilization and TCF4 transcriptional activity in both metastatic and non‐metastatic murine OS cell lines. Metastatic OS cell lines showed better chemotaxis response to Wnts than the non‐metastatic OS cell lines. Immunohistochemistry studies of 44 human OS samples demonstrated that Wnt10b expression correlated with decreased overall survival.

Conclusions

These results further supports a possible autocrine or paracrine Wnt pathway in metastatic potential of OS. Pediatr Blood Cancer 2008;51:349–355. © 2008 Wiley‐Liss, Inc.
Two‐dimensional Fourier transform infrared correlation spectroscopy and evolving factor analysis in the study of cationic curing of DGEBA and γ‐valerolactone mixtures
Authors: Spegazzini Nicolás , Ruisánchez Itziar , Larrechi M. Soledad , Serra Angels , Mantecón Ana
Published: May 2008

Generalized two‐dimensional (2D) correlation spectroscopy and evolving factor analysis (EFA) have been applied to the study of cationic curing reaction of mixtures of diglycidyl ether of bisphenol A (DGEBA) and γ‐valerolactone (γ‐VL). The reaction has been monitored by Fourier transform infrared spectroscopy. The reaction periods in which a chemical change takes place are identified using EFA and then the sequence of changes are established by means of the interpretation of the synchronous and asynchronous spectra obtained with 2D correlation spectroscopy. By combining this information, in the curing process, four reactions have been detected: (1) DGEBA and γ‐VL reaction to obtain a spiroorthoester intermediate, (2) homopolymerization of DGEBA, (3) copolymerization of DGEBA with the spiroorthoester intermediate, and (4) homopolymerization of the spiroorthoester. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3886–3899, 2008
Self‐assembly and morphology of polydimethylsiloxane supramolecular thermoplastic elastomers
Authors: Botterhuis Nicole E. , van Beek D. J. M. , van Gemert Gaby M. L. , Bosman Anton W. , Sijbesma Rint P.
Published: May 2008

Functionalization of polydimethylsiloxanes (PDMS) polymers with hydrogen‐bonding ureidopyrimidinone (UPy) groups leads to supramolecular thermoplastic elastomers. In previous studies, no lateral stacking of UPy dimers was observed in UPy‐functionalized polymers, unless additional urethane or urea groups were built into the hard block. However, we have shown that when PDMS is used as the soft block, this lateral aggregation of UPy dimers does take place, since long fibers could be observed in the atomic force microscopy (AFM) phase image. Also in bulk, the presence of these interactions was proven by oscillatory shear experiments. We attribute this aggregation to the incompatibility of soft block and hard block, leading to phase separation. Moreover, we have shown that additional urethane or urea groups in the hard block do lead to materials with more fibers and higher melting points. For the UPy‐urea functionalized PDMS even single fibers are observed with AFM when dropcasted from a very diluted solution. When the length of the soft block is increased, the morphology changes from fibrous to spherical. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3877–3885, 2008
Synthesis of amphiphilic graft copolymer brush and its use as template film for the preparation of silver nanoparticles
Authors: Lee Kyung Ju , Park Jung Tae , Goh Joo Hwan , Kim Jong Hak
Published: May 2008

A microphase‐separated, amphiphilic graft copolymer consisting of a poly (vinyl chloride) (PVC) backbone and poly(oxyethylene methacrylate) (POEM) side chains, (PVC‐g‐POEM at 62:38 wt %) was synthesized via atom transfer radical polymerization (ATRP). Nuclear magnetic resonance (1H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM) clearly revealed that the “grafting from” method using ATRP was successful and that the graft copolymer molecularly self‐assembled into discrete nanophase domains of continuous PVC and isolated POEM regions. The self‐assembled graft copolymer film was used to template the growth of silver nanoparticles in solid state by introducing a AgCF3SO3 precursor and a UV irradiation process. The in situ formation of silver nanoparticles in the graft copolymer template film was confirmed by TEM, UV–visible spectroscopy, and wide angle X‐ray scattering. FTIR spectroscopy and X‐ray photoelectron spectroscopy also demonstrated the selective incorporation and in situ formation of silver nanoparticles within the hydrophilic POEM domains, presumably due to strong interactions between the silver and the ether oxygen in POEM. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3911–3918, 2008
Dichloroacetate (DCA) sensitizes both wild‐type and over expressing Bcl‐2 prostate cancer cells in vitro to radiation
Authors: Cao Wengang , Yacoub Saif , Shiverick Kathleen T. , Namiki Kazunori , Sakai Yoshihisa , Porvasnik Stacy , Urbanek Cydney , Rosser Charles J.
Published: May 2008

Background

Bcl‐2 protects cells from apoptosis and provides a survival advantage to cells over‐expressing this oncogene. In addition, over expression of Bcl‐2 renders cell resistant to radiation therapy. Recently, dichloroacetate (DCA) was proven to potentiate the apoptotic machinery by interacting with Bcl‐2. In this study, we investigated whether treating human prostate cancer cells with DCA could modulate Bcl‐2 expression and if the modulation in Bcl‐2 expression could render the Bcl‐2 over expressing cells more susceptible to cytotoxicity effects of radiation.

Methods

PC‐3‐Bcl‐2 and PC‐3‐Neo human prostate cancer cells treated with DCA in addition to irradiation were analyzed in vitro for changes in proliferation, clonogenic survival, apoptosis, cell cycle phase distribution, mitochondrial membrane potential, and expression of Bcl‐2, Bcl‐xL, Bax, or Bak proteins.

Results

DCA alone produced significant cytotoxic effects and was associated with G1 cell cycle arrest. Furthermore, DCA was associated with an increased rate of apoptosis. The combination of DCA with irradiation sensitized both cell lines to radiation's killing effects. Treatment of PC‐3‐Bcl‐2 or PC‐3‐Neo with DCA and irradiation resulted in marked changes in various members of the Bcl‐2 family. In addition, DCA therapy resulted in a significant change in mitochondria membrane potential, thus supporting the notion that DCAs effect is on the mitochondria.

Conclusions

This is the first study to demonstrate DCA can effectively sensitize wild‐type and over expressing Bcl‐2 human prostate cancer cells to radiation by modulating the expression of key members of the Bcl‐2 family. Together, these findings warrant further evaluation of the combination of DCA and irradiation. Prostate 68: 1223–1231, 2008. © 2008 Wiley‐Liss, Inc.
Fast near‐infra‐red spectroscopic Mueller matrix ellipsometer based on ferroelectric liquid crystal retarders
Authors: Ladstein J. , Stabo‐Eeg F. , Garcia‐Caurel E. , Kildemo M.
Published: May 2008

The cover picture of this issue of physica status solidi (c) has been taken from the article [1]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the binding mode of urease active site inhibitors: A density functional study
Authors: Leopoldini M. , Marino T. , Russo N. , Toscano M.
Published: May 2008

The way with which boric acid, a rapid reversible competitive inhibitor, binds the urease active site was explored at density functional B3LYP level of theory. The catalytic core of the enzyme was simulated by two models of different size. In both cases, amino acid residues belonging to the inner and to the outer coordination spheres of nickel ions were replaced by smaller molecular species. Contrary to the experimental indication that attributes the inhibitory ability of this acid to the lack of a nucleophilic attack by the enzyme to the boron atom, we instead found that another possibility exists based on the presence of a strong covalent σ bond between boron and urease that we think can be hardly broken to allow any course of the reaction. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Risk and the strategy of foreign location choice in regulated industries
Authors: García‐Canal Esteban , Guillén Mauro F.
Published: May 2008

We argue that firms in regulated industries react to macroeconomic and policy risks in sharply different ways. While they seek to avoid countries with high levels of macroeconomic uncertainty, we predict that they find it more attractive to expand into countries characterized by governments with discretionary policymaking capacities so as to be able to negotiate favorable conditions of entry. We also argue that firms are heterogeneous in their attitudes toward risk. We predict that firms in which the state holds a partial equity stake exhibit a more tolerant attitude. We also expect that as firms accumulate foreign experience, they develop an aversion toward further foreign entries into politically unstable markets. Support for these predictions is provided by an analysis of the Latin American market entries of all listed Spanish firms in regulated industries between 1987 and 2000. Copyright © 2008 John Wiley & Sons, Ltd.
Systems engineering perspectives on the 2500‐year‐old Art of War by Sun Tzu
Authors: Foo Check Teck
Published: May 2008

Just how old are the ideas underpinning the interdisciplinary, holistic systems engineering? (See J.G. Landels, Engineering in the Ancient World, University of California Press, Berkeley, 2000.) In this paper, the author illustrates how some of the fundamental thinking, philosophy and approaches of systems engineering are deeply embedded in the classical, 2500‐year‐old Chinese Art of War by Sun Tzu. To do this, the author draws upon the definitions and conceptualizations of systems engineering by INCOSE or endorsed by INCOSE Fellows. For the citations of Art of War in English, he draws upon an almost century old translation in 1910 by Lionel Giles [http://www.chinapage.com/sunzi‐e.html]. Specifically, an illustration is provided on how Sun Tzu emphasized critically the importance of subsystems within a system. Also 2.5 millennia ago Sun Tzu had already predicated that performance outcomes were dependent upon a ‘‘quantifying’’ information. Finally, corporate strategy processes in the ASEAN region as inspired by the Art of War of Sun Tzu are contrasted by the author with the conceptualization of seven facets of systems engineering by Bahill and Gissing [IEEE Trans Syst Man Cybernet Part C Appl Rev 28(4) (1998), 516– 527]. © 2008 Wiley Periodicals, Inc. Syst Eng
Effect of Dietary Fiber and Growth Hormone on Colonic Adaptation in Short Bowel Syndrome Treated by Enteral Nutrition
Authors: Xu Jianmin , Zhong Yunshi , Jin Dayong , Zhang Hongwei , Wu Zhaohan
Published: May 2008

Background

Colon adaptation can partially compensate for the reduced capacity of nutrient absorption in patients with short bowel syndrome (SBS).

Objective

The aim of this study was to assess the effect of combined treatment with enteral nutrition (EN), dietary fiber, and recombinant human growth hormone (rhGH) on promoting colonic adaptation.

Methods

A group of 40 male Sprague‐Dawley rats undergoing up to 80% to 85% small intestine resection were randomly assigned to four groups of 10 rats each: enteral nutrition (EN, the control); enteral nutrition/dietary fiber (EF); enteral nutrition/rhGH (EG); and enteral nutrition/dietary fiber/rhGH (EFG). All groups received isonitrogenous, isocaloric enteral feeding for 21 days. Body weight, daily nitrogen balance, colonic morphology, DNA, insulin‐like growth factor‐1/IGF‐1 receptor (IGF‐1)/IGF‐1R) expression were determined.

Conclusion

Morphologic adaptation of the colon (including increased mucosal thickness and plica height, enlarged surface area, increased hyditloid cells) was observed on postoperative day 21. GH is superior to fiber in several aspects: increasing colon diameters (0.46 ± 0.03 vs. 0.38 ± 0.02 cm, P < 0.05), villous height (356 ± 23 vs. 307 ± 21 μm, P < 0.05) and total surface area (15,222 ± 1344 vs. 13,178 ± 1727 μm2, P < 0.05). Increased DNA content—1.66 ± 0.13 (EG) and 1.71 ± 0.13 (EGF) vs. 1.28 ± 0.11(EF), P < 0.05—in the colon was also found in the EG and EGF groups. GH administration led to a significant increase in plasma IGF‐1 (439.6 ± 88.3 ng/ml in the EG group, 455.4 ± 107.4 ng/ml in the EGF group) and growth hormone (9.29 ± 6.49 ng/ml in the EG group, 9.68 ± 3.26 ng/ml in the EGF group) as compared to the EN group (IGF‐1, 328.7 ± 68.1 ng/ml; GH, 5.81 ± 2.41 ng/ml) and the EF group (IGF‐1, 356.4 ± 52.1 ng/ml; GH, 6.51 ± 4.66 ng/ml). Analysis of IGF‐1 and IGF‐1 receptor mRNA also demonstrated a significantly higher IGF‐1 mRNA in the EG and EFG groups than in the EN and EF groups. Colon functional adaptation was also associated with accelerated absorptive function of water in the EF, EG, and EGF groups. Improved nutritional status (body weight, nitrogen retention, plasma protein) were seen in the EG and EGF groups. Dietary fiber, in combination with growth factor, synergistically promoted colon adaptation in the SBS animal model and facilitated maintenance of daily nutritional needs in rodents.
Influence of Fatty Acid Profile of Total Parenteral Nutrition Emulsions on the Fatty Acid Composition of Different Tissues of Piglets
Authors: Amusquivar E. , Sánchez M. , Hyde M. J. , Laws J. , Clarke L. , Herrera E.
Published: May 2008

Total parenteral nutrition (TPN) studies in human babies of very‐low‐birth‐weight suggest that the lipid emulsions currently available are not optimum for neonatal nutrition. Since fatty acid metabolism in human and pigs is very similar, the present study examines how lipid emulsions used in clinical TPN (i.e. ClinOleic, Intralipid, Lipofundin or Omegaven), with different fatty acid compositions, administered to neonatal piglets for 7 days, influenced their tissue fatty acid composition as compared to those enterally fed with a sow milk replacer. A positive linear relationship was found between the proportion of all individual fatty acids in the lipid emulsions or in the milk replacer versus those in plasma, skeletal muscle, subcutaneous fat, liver, heart, pancreas, stomach or intestine total lipids or in brain phospholipids, the latter showing the lowest correlation coefficient. With the exception of brain, the proportion of either oleic acid or α‐linolenic acid in the individual tissues was correlated with those present in the corresponding lipid emulsion or milk replacer, whereas the proportion of linoleic acid correlated significantly with all the tissues studied. With the exception of brain phospholipids, both eicosapentaenoic and docosahexaenoic acids were higher in the tissues of piglets receiving Omegaven than in all other groups. In conclusion, with the exception of the brain, fatty acid composition of plasma and different tissues in piglets are strongly influenced by the fatty acid profile of TPN emulsions. Fatty acid composition of brain phospholipids are, however, much less influenced by dietary composition, indicating an active and efficient metabolism that ensures its appropriate composition at this key stage of development.
Phase Transition of Sunflower Oil as Affected by the Oxidation Level
Authors: Calligaris Sonia , Arrighetti Gianmichele , Barba Luisa , Nicoli Maria Cristina
Published: May 2008

The influence of the oxidation level on the phase transition behavior of sunflower oil was evaluated by differential scanning calorimetry (DSC) and synchrotron X‐ray diffraction (XRD) at both small and wide angles. The crystallization was monitored at a cooling/heating rate of 2 °C/min from 20 to −80 °C and vice versa applying both techniques. The triacylglycerols organize in two double‐chain length structures: α 2L (61.87 Å) and β′ 2L (82.89 Å). The crystalline structure changes upon oxidation. In particular, the intensity of the XRD peak associated with the double‐chain structure of β′, as well as its crystallization and melting enthalpy, significantly decreases as the oxidation level increases.
Standing waves for nonlinear Schrödinger equations with singular potentials
Authors: Byeon Jaeyoung , Wang Zhi-Qiang
Published: May 2008

We study semiclassical states of nonlinear Schrödinger equations with anisotropic type potentials which may exhibit a combination of vanishing and singularity while allowing decays and unboundedness at infinity. We give existence of spike type standing waves concentrating at the singularities of the potentials.

Nous étudions les états semi-classiques des équations de Schrödinger non linéaires avec potentiels de type anisotropiques qui peuvent tendre vers zéro à l'infini, pour lesquels des phénomènes d'évanescence et de singularité sont possibles. Nous donnons l'existence d'ondes stationnaires se concentrant aux singularités des potentiels.
Medication adherence in patients with chronic non‐malignant pain: Is there a problem?
Authors: Broekmans Susan , Dobbels Fabienne , Milisen Koen , Morlion Bart , Vanderschueren Steven
Published: May 2008

Health care providers, treating patients with chronic non‐malignant pain, often experience that medication is not as effective as expected. It is important to realize that the effectiveness of a pharmacological treatment can be influenced by the way the medication is taken. Medication adherence is a topic that gains more attention, especially in chronic conditions, because it affects treatment outcome. A systematic review of studies on medication adherence in patients with chronic non‐malignant pain was performed to gain insight in the prevalence of the problem, the impact on treatment outcome, influencing variables and interventions. Searching several electronic databases (Medline, CINAHL, Psychinfo and Cochrane), 14 relevant articles were found. The results indicate that medication non‐adherence is common in patients with chronic non‐malignant pain. Both overuse and underuse of medication occurs. However, due to the scarce literature and important methodological limitations, it is not possible to make firm conclusions concerning the impact on outcome, influencing variables and optimal intervention strategies. This review highlights some important gaps in the adherence literature in a chronic non‐malignant pain population and sets the stage for future research.
A Novel Automated Approach to Enabling High-Throughput Cell Line Development, Selection, and other Cell Culture Tasks Performed in Erlenmeyer (Shake) Flasks
Authors: Thomas Dave , Ward Tim , Drake Rosemary , Hollway Rick , Savage David , Owen Steve
Published: May 2008

Selection of the optimum cell line from large populations can be time consuming and laborious. Compromises are often necessary to meet challenging timelines, but can limit the parameters or cell line construction strategies that can be evaluated. This article describes a new automated cell culture system for cell line selection and characterization. The technologies enable data to be obtained from large numbers of cells lines allowing users to evaluate, in parallel, a wider range of molecular approaches and cell culture processes. This facilitates more rapid and efficient cell line development. Also, presented are initial biological testing data for the new system and descriptions of how highly parallel processing can contribute to significantly reduced cycle times and better decision making through the rapid identification of optimum cell lines and culture conditions.
An analysis of the impact of timberland, farmland and commercial real estate in the asset allocation decisions of institutional investors
Authors: Waggle Doug , Johnson Don T.
Published: May 2008

We examine the effects of including timberland, farmland and commercial real estate in a mixed asset portfolio with stocks, government bonds and T‐Bills. Using both smoothed and unsmoothed returns (as per Geltner [Geltner, D. (1993). Estimating market values from appraised values without assuming an efficient market. Journal of Real Estate Research, 8, 25–345.]) and both constrained and unconstrained allocation assumptions (as per Eichhorn, Gupta and Stubbs [Eichhorn, D., Gupta, F., & Stubbs, E. (1998). Using constraints to improve the robustness of asset allocation. Journal of Portfolio Management, Spring, 41–48.]), we employ Markowitz portfolio optimization and find widely varying allocation outcomes. However, timberland entered nearly all portfolios, accounting for large percentages in several scenarios, while farmland entered only low‐risk portfolios. At lower risk levels, commercial real estate dominates the real estate allocation but as acceptable risk levels rise, timberland supplants commercial real estate as the primary component of the portfolio's real estate allocation.
Partition as a Solution to Wars of Nationalism: The Importance of Institutions
Authors: CHAPMAN THOMAS , ROEDER PHILIP G.
Published: May 2008

Civil war settlements create institutional arrangements that in turn shape postsettlement politics among the parties to the previous conflict. Following civil wars that involve competing nation-state projects, partition is more likely than alternative institutional arrangements—specifically, unitarism, de facto separation, and autonomy arrangements—to preserve the peace and facilitate democratization. A theory of domestic political institutions as a constraint on reescalation of conflict explains this unexpected relationship through four intermediate effects—specifically, the likelihood that each institutional arrangement will reinforce incompatible national identities, focus the pursuit of greed and grievance on a single zero-sum conflict over the allocation of decision rights, empower the parties to the previous conflict with multiple escalatory options, and foster incompatible expectations of victory. The theory's predictions stand up under statistical tests that use four alternative datasets.
Effects of “In-Your-Face” Television Discourse on Perceptions of a Legitimate Opposition
Authors: MUTZ DIANA C.
Published: May 2008

How do Americans acquire the impression that their political foes have some understandable basis for their views, and thus represent a legitimate opposition? How do they come to believe that reasonable people may disagree on any given political controversy? Given that few people talk regularly to those of opposing perspectives, some theorize that mass media, and television in particular, serve as an important source of exposure to the rationales for oppositional views. A series of experimental studies suggests that television does, indeed, have the capacity to encourage greater awareness of oppositional perspectives. However, common characteristics of televised political discourse—incivility and close-up camera perspectives—cause audiences to view oppositional perspectives as less legitimate than they would have otherwise. I discuss the broader implications of these findings for assessments of the impact of television on the political process, and for the perspective that televised political discourse provides on oppositional political views.
Leading the Party: Coordination, Direction, and Communication
Authors: DEWAN TORUN , MYATT DAVID P.
Published: May 2008

Party activists face a coordination problem: a critical mass—a barrier to coordination—must advocate a single policy alternative if the party is to succeed. The need for direction is the degree to which the merits of the alternatives respond to the underlying fundamentals of the party's environment. An individual's ability to assess the fundamentals is his sense of direction. These three factors—the barriers to coordination, the need for direction, and an individual's sense of direction—combine to form an index of both the desirability and the feasibility of leadership. We offer insights into Michels' Iron Law: a sovereign party conference gives way to leadership by an individual or oligarchy if and only if the leadership index is sufficiently high. Leadership enhances the clarity of intraparty communication, but weakens the response of policy choices to the party's environment. Our model can also be applied to the coordination problems faced by instrumental voters in plurality-rule elections, and so relates to the psychological effect of Duverger's Law.
Why Does Ethnic Diversity Undermine Public Goods Provision?
Authors: HABYARIMANA JAMES , HUMPHREYS MACARTAN , POSNER DANIEL N. , WEINSTEIN JEREMY M.
Published: May 2008

A large and growing literature links high levels of ethnic diversity to low levels of public goods provision. Yet although the empirical connection between ethnic heterogeneity and the underprovision of public goods is widely accepted, there is little consensus on the specific mechanisms through which this relationship operates. We identify three families of mechanisms that link diversity to public goods provision—what we term “preferences,” “technology,” and “strategy selection” mechanisms—and run a series of experimental games that permit us to compare the explanatory power of distinct mechanisms within each of these three families. Results from games conducted with a random sample of 300 subjects from a slum neighborhood of Kampala, Uganda, suggest that successful public goods provision in homogenous ethnic communities can be attributed to a strategy selection mechanism: in similar settings, co-ethnics play cooperative equilibria, whereas non-co-ethnics do not. In addition, we find evidence for a technology mechanism: co-ethnics are more closely linked on social networks and thus plausibly better able to support cooperation through the threat of social sanction. We find no evidence for prominent preference mechanisms that emphasize the commonality of tastes within ethnic groups or a greater degree of altruism toward co-ethnics, and only weak evidence for technology mechanisms that focus on the impact of shared ethnicity on the productivity of teams.
Demand Commitment and Legislative Bargaining: A Response
Authors: MORELLI MASSIMO
Published: May 2008

In this reply, I will focus on the implications of Montero and Vidal-Puga's finding, acknowledging that their result is correct. Thus, what follows should not be interpreted as a defense of the Proposition 2 of Morelli 1999, but as a clarification of the impact of this correction for the demand bargaining research agenda as a whole.
Framing Public Opinion in Competitive Democracies
Authors: CHONG DENNIS , DRUCKMAN JAMES N.
Published: May 2008

What is the effect of democratic competition on the power of elites to frame public opinion? We address this issue first by defining the range of competitive contexts that might surround any debate over a policy issue. We then offer a theory that predicts how audiences, messages, and competitive environments interact to influence the magnitude of framing effects. These hypotheses are tested using experimental data gathered on the opinions of adults and college students toward two policy issues—the management of urban growth and the right of an extremist group to conduct a rally. Our results indicate that framing effects depend more heavily on the qualities of frames than on their frequency of dissemination and that competition alters but does not eliminate the influence of framing. We conclude by discussing the implications of these results for the study of public opinion and democratic political debate.
The Law of k/n: The Effect of Chamber Size on Government Spending in Bicameral Legislatures
Authors: CHEN JOWEI , MALHOTRA NEIL
Published: May 2008

Recent work in political economics has examined the positive relationship between legislative size and spending, which Weingast et al. (1981) formalized as the law of 1/n. However, empirical tests of this theory have produced a pattern of divergent findings. The positive relationship between seats and spending appears to hold consistently for unicameral legislatures and for upper chambers in bicameral legislatures but not for lower chambers. We bridge this gap between theory and empirics by extending Weingast et al.'s model to account for bicameralism in the context of a Baron–Ferejohn bargaining game. Our comparative statics predict, and empirical data from U.S. state legislatures corroborate, that the size of the upper chamber (n) is a positive predictor of expenditure, whereas the ratio of lower-to-upper chamber seats (k) exhibits a negative effect. We refer to these relationships as the law of k/n, as the two variables influence spending in opposite directions.
Genetic causes and consequences of the breakdown of self-incompatibility: case studies in the Brassicaceae
Authors: MABLE BARBARA K.
Published: May 2008

The genetic consequences of inbreeding is a subject that has received thorough theoretical attention and has been of interest to empirical biologists since the time of Darwin. Particularly for species with genetically controlled mechanisms to promote outcrossing (self-incompatibility or SI systems), it is expected that high levels of genetic load should accumulate through sheltering of deleterious recessive mutations. Nevertheless, transitions to selfing are common across angiosperms, which suggests that the potentially negative consequences of reduced heterozygosity and genetic diversity are balanced by other factors, such as reproductive assurance. This mini-review focuses on empirical research in the Brassicaceae to emphasize some of the genetic consequences of shifts to inbreeding in terms of mechanisms for loss of SI, changes in genetic diversity following loss of SI, and inbreeding depression in relation to outcrossing history. Despite the long history of theoretical attention, there are still some surprisingly large gaps in our understanding in each of these areas. Rather than providing a complete overview, examples are drawn predominantly from published and emerging data fromArabidopsis thalianaand its relatives to highlight recent progress and remaining questions. We are currently on the brink of major breakthroughs in understanding due both to advances in sequencing technology and a shift in focus from crop plants to natural populations, where critical factors such as population structure, phylogeography, demographic history, partial compatibility and individual variation can be taken into account when investigating the nature of the selective forces regulating mating system evolution.
Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snailBiomphalaria pfeifferi
Authors: TIAN-BI YVES-NATHAN T. , N'GORAN ELIEZER K. , N'GUETTA SIMON-PIERRE , MATTHYS BARBARA , SANGARE ABDOURAHAMANE , JARNE PHILIPPE
Published: May 2008

Inbreeding species of hermaphroditic animals practising copulation have been characterized by few copulations, no waiting time (the time that an isolated individual waits for a partner before initiating reproduction compared with paired individuals) and limited inbreeding (self-fertilization) depression. This syndrome, which has never been fully studied before in any species, is analysed here in the highly selfing freshwater snailBiomphalaria pfeifferi. We conducted an experiment under laboratory conditions over two generations (G1and G2) using snails sampled from two populations (100 individuals per population). G1individuals were either isolated or paired once a week (potentially allowing for crosses), and monitored during 29 weeks for growth, fecundity and survival. Very few copulations were observed in paired snails, and there was a positive correlation in copulatory activity (e.g. number of copulations) between the male and female sexual roles. The waiting time was either null or negative, meaning that isolated individuals initiated reproduction before paired ones. G2offspring did not differ in hatching rate and survival (to 28 days) between treatments, but offspring from paired individuals grew faster than those from isolated individuals. On the whole, the self-fertilization depression was extremely low in both populations. Another important result is that paired G1individuals began laying (selfed) eggs several weeks prior to initiating copulation: this is the first characterization of prior selfing (selfing initiated prior to any outcrossing) in a hermaphroditic animal. A significant population effect was observed on most traits studied. Our results are discussed with regard to the maintenance of low outcrossing rates in highly inbreeding species.
Effective population size and tests of neutrality at cytoplasmic genes inArabidopsis
Authors: WRIGHT STEPHEN I. , NANO NARDIN , FOXE JOHN PAUL , DAR VAQAAR-UN NISA
Published: May 2008

Cytoplasmic genomes typically lack recombination, implying that genetic hitch-hiking could be a predominant force structuring nucleotide polymorphism in the chloroplast and mitochondria. We test this hypothesis by analysing nucleotide polymorphism data at 28 loci across the chloroplast and mitochondria of the outcrossing plantArabidopsis lyrata, and compare patterns with multiple nuclear loci, and the highly selfingArabidopsis thaliana. The maximum likelihood estimate of the ratio of effective population size at cytoplasmic relative to nuclear genes inA. lyratadoes not depart from the neutral expectation of 0·5. Similarly, the ratio of effective size inA. thalianais close to unity, the neutral expectation for a highly selfing species. The results are thus consistent with neutral organelle polymorphism in these species or with comparable effects of hitch-hiking in both cytoplasmic and nuclear genes, in contrast to the results of recent studies on gynodioecious taxa. The four-gamete test and composite likelihood estimation provide evidence for very low levels of recombination in the organelles ofA. lyrata, although permutation tests do not suggest that adjacent polymorphic sites are more closely linked than more distant sites across the two genomes, suggesting that mutation hotspots or very low rates of gene conversion could explain the data.
When gametophytic self-incompatibility meets gynodioecy
Authors: EHLERS BODIL K. , SCHIERUP MIKKEL H.
Published: May 2008

The occurrence of gynodioecy among angiosperms appears to be associated with self-compatibility. We use individual-based simulations to investigate the conditions for breakdown of a gametophytic self-incompatibility system in gynodioecious populations and make a comparison with hermaphroditic populations where the conditions are well known. We study three types of mutations causing self-compatibility. We track the fate of these mutations in both gynodioecious and hermaphroditic populations, where we vary the number of S-alleles, inbreeding depression and selfing rate. We find that the conditions for breakdown are less stringent if the population is gynodioecious and that the breakdown of self-incompatibility tends to promote stability of gynodioecious populations since it results in a higher frequency of females. We also find that fecundity selection has a large effect on the probability of breakdown of self-incompatibility, in particular if caused by a mutation destroying the female function of the S-locus.
Mating system and recombination affect molecular evolution in fourTriticeaespecies
Authors: HAUDRY A. , CENCI A. , GUILHAUMON C. , PAUX E. , POIRIER S. , SANTONI S. , DAVID J. , GLÉMIN S.
Published: May 2008

Mating systems and recombination are thought to have a deep impact on the organization and evolution of genomes. Because of the decline in effective population size and the interference between linked loci, the efficacy of selection is expected to be reduced in regions with low recombination rates and in the whole genome of self-fertilizing species. At the molecular level, relaxed selection is expected to result in changes in the rate of protein evolution and the pattern of codon bias. It is increasingly recognized that recombination also affects non-selective processes such as the biased gene conversion towards GC alleles (bGC). Like selection, this kind of meiotic drive in favour of GC over AT alleles is expected to be reduced in weakly recombining regions and genomes. Here, we investigated the effect of mating system and recombination on molecular evolution in fourTriticeaespecies: two outcrossers (Secale cerealeandAegilops speltoides) and two selfers (Triticum urartuandTriticum monococcum). We found that GC content, possibly driven by bGC, is affected by mating system and recombination as theoretically predicted. Selection efficacy, however, is only weakly affected by mating system and recombination. We investigated the possible reasons for this discrepancy. A surprising one is that, in outcrossing lineages, selection efficacy could be reduced because of high substitution rates in favour of GC alleles. Outcrossers, but not selfers, would thus suffer from a ‘GC-induced’ genetic load. This result sheds new light on the evolution of mating systems.
The number, age, sharing and relatedness ofS-locus specificities inPrunus
Authors: VIEIRA JORGE , FONSECA NUNO A. , SANTOS RAQUEL A. M. , HABU TSUYOSHI , TAO RYUTARO , VIEIRA CRISTINA P.
Published: May 2008

In gametophytic self-incompatibility systems, many specificities (different ‘lock-and-key’ combinations) are maintained by frequency-dependent selection for very long evolutionary times. In Solanaceae, trans-specific evolution (the observation that an allele from one species may be more closely related to an allele from another species than to others from the same species) has been taken as an argument for the very old age of specificities. In this work, by determining, for the first time, the age of extantPrunusspecies, we show that this reasoning cannot be applied to Prunoideae. Furthermore, since our sample size is large (allS-RNaseencoding the female component andSFBencoding the male component GenBank sequences), we were able to estimate the age of the oldestPrunusspecificities. By doing so, we show that the lower variability levels at thePrunus S-locus, in comparison with Solanaceae, is due to the younger age ofPrunusalleles, and not to a difference in silent mutation rates. We show that the ancestor to extantPrunusspecies harboured at least 102 specificities, in contrast to the maximum of 33 observed in extantPrunusspecies. Since the number of specificities that can be maintained in a population depends on the effective population size, this observation suggests a bottleneck inPrunusevolutionary history. Loss of specificities may have occurred during this event. Using only information on amino acid sites that determine specificity differences, and a simulation approach, we show that a model that assumes closely related specificities are not preferentially lost during evolution, fails to predict the observed degree of specificity relatedness.
A selective sweep in or near theSilene latifoliaX-linked geneSlssX
Authors: FILATOV D. A.
Published: May 2008

The most prominent feature of Y chromosomes is that they do not recombine and are usually genetically degenerate, containing only a few genes. White campionSilene latifoliahas evolved sex chromosomes relatively recently, probably within the last 10–15 million years. Perhaps due to its recent origin, the Y chromosome in this species has not completely degenerated and most isolated X-linked genes have intact Y-linked homologues. A gene encoding a protein with strong homology to spermidine synthases,Slss, is the exception to this rule, as the Y-linked copy of this gene has apparently lost its function. Here I report evidence for a recent selective sweep in the X-linked copy of this gene (SlssX) that could reflect compensatory evolution in an X-linked gene that has lost a functional Y-linked homologue. The spread and fixation of an advantageous mutation inSlssXhas resulted in a dramatic loss of genetic diversity and an excess of high-frequency derived polymorphisms in this gene. As the sweep has not affected the closely linkedDD44Xgene, the selective advantage of the mutation that has driven the sweep in theSlssXgene might have been less than 1%.
The effect of a barrier to gene flow on patterns of geographic variation
Authors: BARTON N. H.
Published: May 2008

Explicit formulae are given for the effects of a barrier to gene flow on random fluctuations in allele frequency; these formulae can also be seen as generating functions for the distribution of coalescence times. The formulae are derived using a continuous diffusion approximation, which is accurate over all but very small spatial scales. The continuous approximation is confirmed by comparison with the exact solution to the stepping stone model. In both one and two spatial dimensions, the variance of fluctuations in allele frequencies increases near the barrier; when the barrier is very strong, the variance doubles. However, the effect on fluctuations close to the barrier is much greater when the population is spread over two spatial dimensions than when it occupies a linear, one-dimensional habitat: barriers of strength comparable with the dispersal range (B≈σ) can have an appreciable effect in two dimensions, whereas only barriers with strength comparable with the characteristic scale (B\! \approx\! L \equals \sigma \sol \sqrt {2 \mu}\hskip2) are significant in one dimension (μ is the rate of mutation or long-range dispersal). Thus, in a two-dimensional population, barriers to gene flow can be detected through their effect on the spatial pattern of genetic marker alleles.
Women under Italian Fascism
Authors: Grand Alexander De
Published: May 2008

Perhaps because the subject seemed so obvious, there has been little work done on women under fascism. This omission is unfortunate not only because Fascist policy was more complicated than the general impression of it but also because it offered an interesting example of the interaction between propaganda and reality in an authoritarian society. Women played an important role in several major propaganda campaigns of fascism, such as the ruralization policy and the battle to increase the birth rate. Concern for the role of women was at the heart of the conservative and stabilizing nature of fascism and, in so far as it meant the subjugation of the private lives of citizens to the demands of the State, policy towards women reflected the totalitarian and imperialistic side of fascism as well.