bluuebunny/crossref_metadata_2025 huggingface dataset:
A Feasible and Objective Concept of Optimal Monetary Policy: The Quadratic Loss Function in the Postwar Period
Authors: Duarte Pedro Garcia
Published: February 2009

Monetary economists argue that they adopted quadratic loss functions because the latter delivered easy solutions to complex stochastic models. In that narrative, Simon (1956) and Theil (1957) are mentioned by their proofs that models with quadratic objective functions have the certainty equivalence property, which made their solutions feasible for the computers available at that time. Appearing in that narrative are Poole (1970) and Sargent and Wallace (1975), who were among the first to apply the tool to monetary economics. In this article I argue that in addition to offering “solutions feasibility,” the use of a quadratic loss function to characterize the behavior of central banks also inaugurated an objective way of talking about optimality. In this respect, the tool stabilized the discourse on optimal monetary policy.
F. Y. Edgeworth'sTreatise on Probabilities
Authors: Baccini Alberto
Published: February 2009

Probability theory has a central role in Edgeworth's thought; this article examines the philosophical foundation of the theory. Starting from a frequentist position, Edgeworth introduced some innovations to the definition of primitive probabilities. He distinguished between primitive probabilities based on experience of statistical evidence, and primitive a priori probabilities based on a more general and less precise kind of experience, inherited by the human race through evolution. Given primitive probabilities, no other devices than the rules of calculus of probabilities are necessary for inferring complex probabilities, as the ones defined by Bayes's theorem—an enlargement of the frequentist tradition as defined by Venn. The notion of probability is objective; the passage from the objective sphere to the epistemic one requires rules external to the theory of probability. Edgeworth distinguishes between two notions: credibility, which is the direct translation of probability into the epistemic sphere and which obeys the same rules of the latter; and belief, which has a weak relation with probability, based as it is not only on experiential knowledge, but also on “instinct and sentiment.” According to a nineteenth-century tradition, belief is the base of human action; Edgeworth concludes therefore that probability is not useful for the theory of decision. We propose to classify Edgeworth's theory of probability as precursor of modern eclectic or pluralistic tradition on probability, and according to which probability has an irreducible dualistic nature.
One Analogy Can Hide Another: Physics and Biology in Alchian's “Economic Natural Selection”
Authors: Levallois Clément
Published: February 2009

Today, Alchian's “Uncertainty, Evolution, and Economic Theory” (1950) is hailed by evolutionary economists as a most important piece that resumed an evolutionary brand of theorizing in economics after the eclipse of the interwar period. On the other hand, Alchian's article is also cherished by mainstream economists who consider it to be a powerful defense of the maximization principle in the theory of the firm. Our examination of the early intellectual life of Alchian shows that it was his involvement in military systems analysis at the RAND Corporation that led him to reckon that uncertainty was a fundamental obstacle to marginal analysis. We then demonstrate that Alchian's economic natural selection is a statistical argument that, if phrased in biological parlance, owes its logic to statistical mechanics. This invites us to reconsider the strong opposition usually made between evolutionist and mechanist modes of thinking.
March 1968 in Poland
Authors: Godzich Wlad
Published: February 2009

Since the three partitions it suffered in the eighteenth century, Poland has been eccentric to the main currents of European history, sometimes lagging behind them, sometimes anticipating them. In March 1968, Polish students and intellectuals anticipated their European and American counterparts by challenging the regime in power. This essay traces the intellectual genealogy of the March 1968 movement, focusing on the importance of nihilism and on the coming to grips with evil in human history. A summary account of the events of 1968 in Poland is provided.
The Philosophy of Restoration: Alain Badiou and the Enemies of May
Authors: Power Nina , Toscano Alberto
Published: February 2009

Alain Badiou has defined his philosophical project in terms of the attempt to account for the abandonment and betrayal of the revolutionary impetus in the 1970s. This article examines this contention by tracking the way in which the definition of different antipolitical or anti-emancipatory figures plays a crucial role in the development of Badiou's theory of political subjectivity. How are we to think subjects which oppose, betray, or neutralize egalitarian militancy, or what Badiou would call fidelity to a truth-procedure? The article combines an account of this little-explored aspect of Badiou's theory of the subject with a historical contextualization and periodization, touching on the importance of the theory of “revisionism,” the development of an account of reactive subjectivity, the humanism and antihumanism debate, and Badiou's cartography of a “philosophical front” in terms of “deviations” from a militant line. These various elements will converge in Badiou's portrait of the subjectivity proper to the moment that followed les années rouges of the sixties and seventies—the period which he calls the Restoration, and whose latest incarnation he has identified in the “transcendental Pétainism” of French President Nicolas Sarkozy.
Rethinking the Armed Struggle in Latin America
Authors: Beverley John
Published: February 2009

Representation of the period of armed struggle in Latin America, which extends from the early 1960s to the mid-1980s, has been dominated by a paradigm of disillusion that equates the armed struggle as a political strategy with an excess of youthful idealism or voluntarism. Waning of neoliberal hegemony and the resurgence of the Latin America Left in recent years has brought a need to revise this paradigm. The eventual defeat of the armed struggle, and the problems experienced in countries where it triumphed, such as Cuba or Nicaragua, does not mean that it was an error from the start. There were good reasons in many Latin American countries to suppose that armed struggle might be a viable, or in some cases even a necessary, strategy. For awhile, the international conjuncture of forces in fact favored armed struggle. Much has been made of the limitations of the cultural politics of the revolutionary movements, particularly around questions of race, gender, and ethnicity, and sexual preference. But the very fact that these questions can be raised is due in part to the fact that the revolutionary movements put them centrally on the agenda of modern Latin American life. Rather than seeing, as is fashionable, the new social movements as clearly separate from the armed struggle's goal of capturing state power in the name of the people, it would be more appropriate to see them as outgrowths of the same force that fed the armed struggle.
Martí in His (Third) World
Authors: Retamar Roberto Fernández
Published: February 2009

This essay on Cuba's national poet, José Martí, written originally in the early 1960s for a non-Cuban audience in the wake of the victory of the Cuban Revolution, acquires a new context with the neo-imperialism of the Bush regime and the recent resurgence of the Latin American Left. Martí was one of the first thinkers of revolutionary anticolonial struggle, and in that sense it is legitimate to see him as the main ideological inspiration of the Cuban Revolution itself some sixty years after his death. Yet Martí's own relation to Marx—his near contemporary—and socialism was ambiguous. Martí's work cannot be contained within the formula of bourgeois-democratic nationalism. Rather, as in the case of other thinker/poet/activists of the periphery, who form his legitimate “family,” he represents the case of a maximum possible radicalism, at once aesthetic and political, which responds directly to the concrete character of Cuban society in his time, the struggle against Spanish imperialism, then in decline, and a U.S. imperialism in ascendancy, and the concrete evolution of the Cuban independence movement, more and more obliged to rely on the popular classes. Martí developed the key concept of a multiracial and multicultural “our America” as a counterweight to the menace of U.S. hegemony in the region, on the one hand, and Latin American development schemes based on the imposition of European or North American models, on the other. While he did not himself embrace socialism, the character of both his thought and political goals suggests an affinity with the socialist character assumed by the Cuban Revolution.
1960s East and West: The Nature of the Shestidesiatniki and the New Left
Authors: Kagarlitsky Boris
Published: February 2009

Boris Kagarlitsky examines the rise of political dissent in the East and West during the 1960s. The shestidesiatniki (sixties' generation) in the Soviet Union, he argues, have much more in common with the New Left than was realized at the time, or has been acknowledged since. They shared common sources, ideals, and objectives, drawing on Marxist tradition and striving for “socialism with a human face.” Both movements took shape in the relative prosperity of the postwar period, when frustration grew over the betrayal of democratic and socialist ideals. The mutual unintelligibility of the two movements is ascribed to certain key differences in their demographics and strategies. While the New Left took shape as a youth movement, the shestidesiatniki represented a generation that had been through World War II and identified with the reforms undertaken from within the Soviet government in the 1950s. Where the former aspired to subvert established power, the latter still believed that the system might continue to be changed from within. Thus the two movements looked quite different, even as they espoused similar ideas and shared many common experiences. Both groups took the “long path through the institutions” to finally attain power, though not in the form that they had originally sought, and, for the most part, without the anticipated results. William Nickell's introduction comments on the historiographical aspect of the work, emphasizing its interest as a “cultural tectonic” description of common ground that was obscured by the antagonism of the cold war years.
“Long Time”: Last Daughters and the New “New South”
Authors: Spillers Hortense J.
Published: February 2009

This essay looks at aspects of new southern culture against the backdrop of the 2007 Supreme Court ruling on school desegregation and its impact on our understanding of the sixties. Incorporating two book reviews, the essay argues that the “long” perspective on the period of radical change would suggest that the sixties were not only not a “failure” but in certain respects loom ahead of us.
The End of the Sixties
Authors: Connery Christopher
Published: February 2009

The essay considers the sixties as a global irruption of political and cultural revolution, of world-making of various kinds: decolonization, new subjectivities, new forms of daily life and politics, and new scenes of the political. It holds the sixties to be a global phenomenon, whereby events as disparate as the Chinese Cultural Revolution and the rise of the U.S. counterculture were linked through their contemporaneity, through the shared global situation to which all uprisings were responses, and through the extraparty character of radical politics in the realm of the every day. The essay's central focus is on the Sino-Soviet split, on how one of the most radical elements of sixties' ideology became the impetus for rapprochement with the U.S. and attendant deradicalization. In considering the sixties' end, the essay rejects a discourse of failure or unintended consequences, and seeks to consider, through an examination of ways in which the energies of the period were transformed, a new way of approaching the temporal politics of the period.
The rule of rescue in clinical practice
Authors: Hughes Jonathan , Walker Tom
Published: February 2009

People often have a strong intuitive sense that we ought to rescue those in serious need, even in cases where we could produce better outcomes by acting in other ways. It has become common in such cases to refer to this as the Rule of Rescue. Within the medical field this rule has predominantly been discussed in relation to decisions about whether to fund particular treatments. While, in this setting, the arguments in favour of the Rule of Rescue have generally been found to be unconvincing, there are some reasons for thinking that it may have more of a role to play at the clinical level. In this article, we examine three lines that such reasoning might take. In each case, we argue that the reasons given do not support the adoption of a Rule of Rescue in clinical practice.
Facial emotion recognition in patients with bipolar I and bipolar II disorder
Authors: Derntl Birgit , Seidel Eva‐Maria , Kryspin‐Exner Ilse , Hasmann Alexander , Dobmeier Matthias
Published: February 2009

Objectives. The ability to recognize facial emotional expressions is a fundamental skill that is necessary for successful social interaction. Previous studies examining this competency in patients with bipolar disorder have generated mixed results. Since bipolar patients show multiple psychosocial difficulties even after remission, this study was aimed at further elucidating emotion recognition deficits in bipolar patients.

Methods and design. Sixty‐two stable bipolar out‐patients (37 females; 25 males) and 62 matched healthy controls participated in the study. Explicit facial emotion recognition accuracy was measured with a computerized task.

Results. Analysis of emotion recognition performance revealed no gender effect but a significant group effect, indicating significantly worse accuracy in patients with bipolar I. Patients with bipolar II disorder did not differ significantly from healthy controls. These results were not correlated with either residual symptoms or intellectual impairments.

Conclusions. Based on our results, patients with bipolar disorder vary not only in diagnosis, but also in social cognitive functions, all of which should be addressed in clinical treatment. Future studies should clarify whether emotion recognition deficits are involved in the development and maintenance of bipolar disorder.
Hall effect in Taylor-phase and decagonal Al3(Mn,Fe) complex intermetallics
Authors: Stanic Denis , Ivkov Jovica , Smontara Ana , Jaglicic Zvonko , Dolinsek Janez , Heggen Marc , Feuerbacher Michael
Published: February 2009

The Hall coefficient (R
H) of Al73Mn27–xFex (x = 0, 2, 4 and 6) complex metallic alloys has been measured in the temperature interval from 90 to 400 K. All the alloys are T (Taylor) phase except Al73Mn21Fe6 that is a decagonal (d) quasicrystal. The Hall coefficients of all the samples are positive and they decrease strongly with the increase of temperature according to the Curie-Weiss [C/(Tθ)] law. Therefore, for the separation of the normal (R
0) and anomalous (RS
) Hall coefficients, the results for the paramagnetic susceptibility (χ) in the corresponding temperature interval have been used. The values deduced from R
H(χ) plots are about –2 × 10–10 m3 C–1 for R
0, and about 5 × 10–7 m3 C–1 for RS
. When the possible dependence of RS
on temperature, that is due to the temperature dependence of the electrical resistivity ρ(T), is taken into account the values are about zero for R
0, and about 3 × 10–7 m3 C–1 for RS
(295 K). No significant composition dependence of R
0 has been detected.
Antiferromagnetism in two-dimensional quasicrystals
Authors: Jagannathan Anuradha , Szallas Attila
Published: February 2009

Quasiperiodic structures possess long range positional order, but are freed of constraints imposed by translational invariance. For spins interacting via Heisenberg couplings, one may expect therefore to find novel magnetic configurations in such structures. We have studied magnetic properties for simple two dimensional models, as a first step towards understanding experimentally studied magnetic quasicrystals such as the Zn–Mg–R(rare earth) compounds. We analyse properties of the antiferromagnetic groundstate and magnon excitation modes for bipartite tilings such as the octagonal and Penrose tilings. In the absence of frustration, one has an inhomogeneous Neel-ordered ground state, with local quantum fluctuations of the local staggered magnetic order parameter. We study the spin wave spectrum and wavefunctions of such antiferromagnets within the linear spin wave approximation. Some results for spin-spin correlations in these systems are discussed.
Nanocrystallization and structural correlation in quasicrystalline and crystalline phases during mechanical milling
Authors: Tiwari Radhey Shyam , Yadav Thakur Prasad , Mukhopadhyay Nilay K. , Shaz Mohammad Abu , Srivastava Onkar Nath
Published: February 2009

The main objective of the proposed work is to investigate the formation of nanoquasicrystalline and related nanocrystalline phases in Al—Cu—Fe system during mechanical milling at the initial stage of milling. The mechanical milling of a quasicrystalline Al65Cu20Fe15 alloy was performed in a high-energy ball mill (Szegvari attritor) by varying milling time from 2.5 min to 60 min under liquid hexane medium at the speed of 400 rpm with a ball to powder ratio of 40 : 1. X-ray diffraction was carried out for evaluating the lattice strain, lattice parameters and crystallite sizes of the milled sample. It was found that the evolution of monoclinic Al13Fe4 phase from Al65Cu20Fe15 quasicrystalline phase occurred after 2.5 min of milling, which was further confirmed by transmission electron microscopy. After 5 min of ball milling nano size disordered B2 phase (bcc, a = 0.29 nm) was also found. The systematic analysis of the XRD patterns for evolving lattice parameter, sequential strain suggests that the lattice strain during milling has been quite considerable.
Chirality-selective synthesis of carbon nanotubes by catalytic-chemical vapor deposition using quasicrystal alloys as catalysts
Authors: Kajiwara Kazuo , Suzuki Shogo , Sato Hideki , Hata Koicho
Published: February 2009

We study ultrathin quasicrystalline (QC) films as catalysts for the synthesis of carbon nanotubes (CNTs). To optimize the conditions for the synthesis of CNTs with single chirality, it is important to understand the effects of the catalyst on the chirality-selectivity. Among QC alloys found so far, an icosahedral Al–Cu–Fe alloy system with fivefold symmetry was tested for a catalyst in the synthesis of CNTs by alcohol catalytic-chemical vapor deposition (CCVD). Cross-sectional scanning electron microscopic images of the samples revealed that vertically-aligned CNTs were synthesized reproducibly. It implies that QC films have a significant catalytic activity for the synthesis of CNTs. Moreover, preliminary results of chirality-selectivity are obtained by means of resonance Raman scattering. It is suggested that Al–Cu–Fe ultrathin films are useful for the preferential synthesis of armchair-type CNTs, that is, QC nanoclusters play an important role as catalyst in alcohol CCVD.
e/a Determination for the transition metal element TM in Al–Cu–TM–Si (TM = Fe and Ru) approximants and B2-compounds by means of the FLAPW-Fourier method
Authors: Mizutani Uichiro , Asahi Ryoji , Takeuchi Tsunehiro , Sato Hirokazu , Kontsevoi Oleg , Freeman A. J.
Published: February 2009

By using the FLAPW-Fourier method, we could determine the e/a value for Al–Cu–TM–Si (TM = Fe and Ru) 1/1 – 1/1 – 1/1 approximants and several B2 compounds including CuZn, NiZn, NiAl, MnZn, and AlMg. The NiAl, NiZn and MnZn B2-compounds involving the transition metal element as a partner element are found to be no longer regarded as the 3/2 electron compounds. Moreover, we found that the e/a value is not uniquely assigned to a given transition metal element but depends on its surrounding environments. Hence, it is difficult to use it as a universal parameter in an alloy design.
Thermoelectric properties of Al–Pd–Re quasicrystal sintered by Spark Plasma Sintering (SPS): effect of improvement of microstructure
Authors: Takagiwa Yoshiki , Kamimura Takahiko , Hosoi Sizuka , Okada Junpei Tamura , Kimura Kaoru
Published: February 2009

We report the thermoelectric properties of poly-grain Al–Pd–Re icosahedral quasicrystals and discuss an effect of improvement of their microstructure. The improvement of microstructure by using Spark Plasma Sintering (SPS) method resulted into a large increase of the electrical conductivity but less increase of the thermal conductivity. The relative density dramatically increased up to more than 90% by SPS. On the other hand, the microstructure itself does not have critical influence on the Seebeck coefficient, which is found to be strongly correlated with e/a (sample’s compositions). Consequently, the dimensionless figure of merit (ZT) increased three times from 0.05 to 0.15.
Vibrational properties of MgZn2
Authors: Brommer Peter , Boissieu Marc de , Euchner Holger , Francoual Sonia , Gähler Franz , Johnson Mark , Parlinski Krzysztof , Schmalzl Karin
Published: February 2009

We present here simulation results on the dynamical structure factor of the C14 Laves Phase of MgZn2, the simplest of the Mg–(Al,Zn) Frank-Kasper alloy phases. The dynamical structure factor was determined in two ways. Firstly, the dynamical matrix was obtained in harmonic approximation from ab-initio forces. The dynamical structure factor can then be computed from the eigenvalues of the dynamical matrix. Alternatively, Molecular Dynamics simulations of a larger sample were used to measure the correlation function corresponding to the dynamical structure factor. Both results are compared to data from neutron scattering experiments. This comparison also includes the intensity distribution, which is a very sensitive test. We find that the dynamical structure factor determined with either method agrees reasonably well with the experiment. In particular, the intensity transfer from acoustic to optic phonon modes can be reproduced correctly. This shows that simulation studies can complement phonon dispersion measurements.
Spiky density of states in large complex Al–Mn phases
Authors: Trambly de Laissardiere Guy
Published: February 2009

First-principle electronic structure calculations have been performed in crystalline complex phases μ-Al4.12Mn and λ-Al4.6Mn using the TB-LMTO method. The atomic structures contain about 560 atoms in a large hexagonal unit cell. One of the main characteristic of their density of states is the presence of fine peaks the so-called “spiky structure”. From multiple-scattering calculations in real space, we show that these fine peaks are not artifacts in ab-initio calculations, since they result from a specific localization of electrons by atomic clusters of different length scales.
Thermal conductivity of the Al-based quasicrystals and approximants
Authors: Takeuchi Tsunehiro
Published: February 2009

At high temperatures above 200 K, significant increase in thermal conductivity (κ) was observed for the Al-based icosahedral quasicrystals and their corresponding approximants. By comparing the measured κ of the Al—Re—Si 1/1-cubic approximants with their electronic density of states at the Fermi level (ε
F) determined by the low temperature specific heat measurements, we found that the increase in κ at high temperature was most pronounced when ε
F is located at the bottom of the pseudogap. This fact indicates that the large increase in κ is not brought about by the lattice but by the conduction electrons in associated with the narrow pseudogap at ε
F. It is also found that the behavior of κ at high temperature is well accounted for in terms of the bipolar diffusion effect of conduction electrons that is generally employed to analyze κ of the narrow-gap semiconductors and semimetals.
Compressibility of Al64Pd30.4Fe5.6
Authors: Krauss Günter , Gu Qinfen , Feuerbacher Michael , Steurer Walter
Published: February 2009

The stability of C2-Al64Pd30.4Fe5.6, an approximant phase to the icosahdral Al–Fe–Pd quasicrystal, has been investigated by high-pressure X-ray diffraction using a diamond-anvil cell and synchrotron radiation up to 24.30(1) GPa. The material is structurally stable within the framework of the experiment. The unit cell volume as a function of pressure follows a second-order Birch-Murnaghan equation of state with K
0 = 169.5(2.5) GPa. This value is comparable to that of other quasicrystals and approximant phases containing Al and heavy transition metals.
Structure and properties of quasicrystalline and approximant EBPVD coatings of Al-based systems
Authors: Ustinov Anatolii , Polishchuk Sergey , Scorodzievskii Valerii , Telychko Volodymir
Published: February 2009

This paper considers main features of the formation of Al–Cu–Fe and Al–Cr–Fe coatings with complex crystalline structures using high-rate electron beam physical vapour deposition (EBPVD). It is shown that the deposition of the coatings at substrate temperatures below approximately 570 K leads to the formation of nanostructured quasicrystalline or approximant phases. Mechanical behaviour at static and dynamic loadings of the coatings was investigated. It is established that the decreasing of the grain size in the materials to nanoscale values results in significant enhancement of their damping capacity (a mechanical energy dissipation in the materials) at alternate strains. Possibilities of the use of materials based on quasicrystalline and/or approximant phases as hard and high damping coatings for the prevention of early destruction of gas turbine blades are discussed.
Charge transfer in DNA: effective Hamiltonian approaches
Authors: Macia Enrique
Published: February 2009

Aperiodic order plays a very significant role in biology, as it determines most informative content of genomes. Amongst the various physical, chemical or biological phenomena that might be inferred from sequence correlations, charge transfer properties deserve particular attention. Indeed, the nature of DNA-mediated charge migration has been related to the understanding of damage recognition process, protein binding, or with the task of engineering biological processes (e.g. designing nanoscale sensing of genomic mutations), opening new challenges for emerging nanobiotechnologies. Nevertheless, the solution of Schrödinger´s equation with a potential that is given by a one-dimensional array of the double-stranded DNA remains as a main open theme in solid state physics of biological macromolecules. In this contribution, I will shortly review several approaches introduced during the last few years in order to describe charge transfer migration in DNA in terms of tight-binding effective Hamiltonians.
The relationship of thyroid hormone status with myocardial function in stress cardiomyopathy
Authors: Lee Seong Jin , Kang Jun Goo , Ryu Ohk Hyun , Kim Chul Sik , Ihm Sung-Hee , Choi Moon Gi , Yoo Hyung Joon , Hong Kyung Soon
Published: February 2009

Objective

This study aimed to investigate thyroid hormone (TH) status and its relationship with myocardial function as well as clinical and biochemical parameters in stress cardiomyopathy (CMP).

Methods

Forty-five patients with stress CMP (the patient group), 31 patients without stress CMP (the control II group), and 58 healthy subjects (the control I group) were included. Sick euthyroid syndrome (SES) was defined as low total triiodothyronine (T3) with normal TSH levels.

Results

In the patient group at admission, prevalence of SES was 62.2%. Compared with the control I group, the patient group had a decrease in left ventricular ejection fraction (LVEF) and systolic blood pressure (BP) and an increase in troponin-I, CK-MB, and B-type natriuretic peptide (BNP) levels. Total T3 levels were reduced, and anti-thyroid peroxidase antibody (anti-TPO Ab) positivity, C-reactive protein (CRP) and cortisol levels were elevated. Total T3 levels were associated with acute physiology and chronic health evaluation II (APACHE II) score, LVEF, systolic BP, and cortisol levels in multivariate analysis. In the control II group, total T3 levels were not associated with any variables. In the SES (n=28) and myocardial dysfunction (MDys, n=27) subgroups, increased APACHE II score and BNP levels as well as decreased LVEF and systolic BP were significant. Total T3 levels were reduced, and CRP, cortisol and catecholamines levels were elevated. In the MDys subgroup, anti-TPO Ab positivity and titer were increased.

Conclusion

These results suggest that total T3 levels may be associated with myocardial contractility, clinical severity, and cortisol levels. Thyroid autoimmunity may influence myocardial contractility in stress CMP.
Sexual dimorphism of body composition and insulin sensitivity across pubertal development in obese Caucasian subjects
Authors: Brufani Claudia , Tozzi Alberto , Fintini Danilo , Ciampalini Paolo , Grossi Armando , Fiori Rossana , Kiepe Daniela , Manco Melania , Schiaffini Riccardo , Porzio Ottavia , Cappa Marco , Barbetti Fabrizio
Published: February 2009

Background

Puberty is a period of rapid growth associated with metabolic, hormonal, and body composition changes that can influence risk factors for chronic diseases such as type 2 diabetes.

Objective

To evaluate body composition and insulin sensitivity (IS) modifications throughout puberty in a large group of obese Caucasian subjects.

Methods

Five hundred and nineteen obese subjects (4–19 years), grouped according to gender and Tanner stage (T), underwent oral glucose tolerance test. Quantitative insulin check index (QUICKI) and ISI were calculated as indexes of IS. In 309 subjects, body composition by dual-energy X-ray absorptiometry, IGF1, adiponectin, and leptin were also evaluated.

Results

Body composition modifications were sexually dimorphic, with girls not modifying fat and lean percentage and fat distribution (P>0.15), and boys decreasing fat percentage and increasing lean percentage and central fat depot (P<0.001) across Ts. IS decreased during mid-puberty and returned to prepubertal levels by the end of puberty. Girls showed lower IS than boys (P<0.01 and =0.03 for QUICKI and ISI respectively). In multivariate analysis factors that negatively influenced IS, independently from T or age, were total fat mass and central fat depot in girls (P<0.05 and <0.01, respectively), total fat and lean mass in boys (P<0.01). IGF1, adiponectin, and leptin were not related to pubertal IS.

Conclusions

In obese Caucasian subjects, further decrease of IS observed during puberty is a transient phenomenon. Factors that independently from T or age influence IS are central fat depot in girls, lean amount in boys, and total fat mass in both sexes.
FBF and Its Dual Control of gld-1 Expression in the Caenorhabditis elegans Germline
Authors: Suh Nayoung , Crittenden Sarah L , Goldstrohm Aaron , Hook Brad , Thompson Beth , Wickens Marvin , Kimble Judith
Published: February 2009

FBF, a PUF RNA-binding protein, is a key regulator of the mitosis/meiosis decision in the Caenorhabditis elegans germline. Genetically, FBF has a dual role in this decision: it maintains germ cells in mitosis, but it also facilitates entry into meiosis. In this article, we explore the molecular basis of that dual role. Previous work showed that FBF downregulates gld-1 expression to promote mitosis and that the GLD-2 poly(A) polymerase upregulates gld-1 expression to reinforce the decision to enter meiosis. Here we ask whether FBF can act as both a negative regulator and a positive regulator of gld-1 expression and also investigate its molecular mechanisms of control. We first show that FBF co-immunoprecipitates with gld-1 mRNA, a result that complements previous evidence that FBF directly controls gld-1 mRNA. Then we show that FBF represses gld-1 expression, that FBF physically interacts with the CCF-1/Pop2p deadenylase and can stimulate deadenylation in vitro, and that CCF-1 is partially responsible for maintaining low GLD-1 in the mitotic region. Finally, we show that FBF can elevate gld-1 expression, that FBF physically interacts with the GLD-2 poly(A) polymerase, and that FBF can enhance GLD-2 poly(A) polymerase activity in vitro. We propose that FBF can affect polyadenylation either negatively by its CCF-1 interaction or positively by its GLD-2 interaction.
Parentage and Sibship Inference From Multilocus Genotype Data Under Polygamy
Authors: Wang J , Santure A W
Published: February 2009

Likelihood methods have been developed to partition individuals in a sample into sibling clusters using genetic marker data without parental information. Most of these methods assume either both sexes are monogamous to infer full sibships only or only one sex is polygamous to infer full sibships and paternal or maternal (but not both) half sibships. We extend our previous method to the more general case of both sexes being polygamous to infer full sibships, paternal half sibships, and maternal half sibships and to the case of a two-generation sample of individuals to infer parentage jointly with sibships. The extension not only expands enormously the scope of application of the method, but also increases its statistical power. The method is implemented for both diploid and haplodiploid species and for codominant and dominant markers, with mutations and genotyping errors accommodated. The performance and robustness of the method are evaluated by analyzing both simulated and empirical data sets. Our method is shown to be much more powerful than pairwise methods in both parentage and sibship assignments because of the more efficient use of marker information. It is little affected by inbreeding in parents and is moderately robust to nonrandom mating and linkage of markers. We also show that individually much less informative markers, such as SNPs or AFLPs, can reach the same power for parentage and sibship inferences as the highly informative marker simple sequence repeats (SSRs), as long as a sufficient number of loci are employed in the analysis.
Apologia Alexandru (Arrianos: Anabasis 1, 7-9)
Authors: Tóth Iván
Published: February 2009

Kr. e.
335-ben az ifjú makedón uralkodó, III. Alexandros görög szövetségeseivel
megostromolta, majd porig rombolta Thébai városát. A nikomédiai Arrianos
részletesen beszámol a görög világot meg_
Putting watershed restoration in context: Alternative future scenarios influence management outcomes
Authors: Fullerton A. H. , Steel E. A. , Caras Y. , Sheer M. , Olson P. , Kaje J.
Published: February 2009

Predicting effects of habitat restoration is an important step for recovery of imperiled anadromous salmonid populations. Habitat above three major hydropower dams in the Lewis River watershed, southwestern Washington, USA, will soon become accessible to anadromous fish. We used multiple models to estimate habitat conditions above dams and fish population responses. Additionally, we used scenario planning to predict how habitat and fish will respond to potential future trends in land use due to human population growth and riparian conservation policies. Finally, we developed a hypothetical management strategy (i.e., a set of prioritized restoration projects in specific locations within the watershed) as an example of how a fixed amount of restoration funds might be spent to enhance the success of reintroducing fish above dams. We then compared predicted outcomes from this new strategy to those of six previously modeled strategies. We estimated how the choice of the best management strategy might differ among alternative future scenarios. Results suggest that dam passage will provide access to large amounts of high‐quality habitat that will benefit fish populations. Moreover, conservation of existing riparian areas, if implemented, has the potential to improve conditions to a much greater extent than restoration strategies examined, despite expected urban growth. We found that the relative performance of management strategies shifted when fish were allowed to migrate above dams, but less so among alternative futures examined. We discuss how predicted outcomes from these seven hypothetical management strategies could be used for developing an on‐the‐ground strategy to address a real management situation.
Sampling design considerations for demographic studies: a case of colonial seabirds
Authors: Kendall William L. , Converse Sarah J. , Doherty Paul F. , Naughton Maura B. , Anders Angela , Hines James E. , Flint Elizabeth
Published: February 2009

For the purposes of making many informed conservation decisions, the main goal for data collection is to assess population status and allow prediction of the consequences of candidate management actions. Reducing the bias and variance of estimates of population parameters reduces uncertainty in population status and projections, thereby reducing the overall uncertainty under which a population manager must make a decision. In capture–recapture studies, imperfect detection of individuals, unobservable life‐history states, local movement outside study areas, and tag loss can cause bias or precision problems with estimates of population parameters. Furthermore, excessive disturbance to individuals during capture–recapture sampling may be of concern because disturbance may have demographic consequences. We address these problems using as an example a monitoring program for Black‐footed Albatross (Phoebastria nigripes) and Laysan Albatross (Phoebastria immutabilis) nesting populations in the northwestern Hawaiian Islands. To mitigate these estimation problems, we describe a synergistic combination of sampling design and modeling approaches. Solutions include multiple capture periods per season and multistate, robust design statistical models, dead recoveries and incidental observations, telemetry and data loggers, buffer areas around study plots to neutralize the effect of local movements outside study plots, and double banding and statistical models that account for band loss. We also present a variation on the robust capture–recapture design and a corresponding statistical model that minimizes disturbance to individuals. For the albatross case study, this less invasive robust design was more time efficient and, when used in combination with a traditional robust design, reduced the standard error of detection probability by 14% with only two hours of additional effort in the field. These field techniques and associated modeling approaches are applicable to studies of most taxa being marked and in some cases have individually been applied to studies of birds, fish, herpetofauna, and mammals.
Ecologically relevant dispersal of corals on isolated reefs: implications for managing resilience
Authors: Underwood Jim N. , Smith Luke D. , Oppen Madeleine J. H. van , Gilmour James P.
Published: February 2009

Coral reefs are in decline worldwide, and marine reserve networks have been advocated as a powerful management tool for maximizing the resilience of coral communities to an increasing variety, number, and severity of disturbances. However, the effective design of reserves must account for the spatial scales of larval dispersal that affect the demography of communities over ecological time frames. Ecologically relevant distances of dispersal were inferred from DNA microsatellite data in a broadcast‐spawning (Acropora tenuis) and a brooding (Seriatopora hystrix) coral at isolated reef systems off northwest Australia. Congruent with expectations based on life histories, levels of genetic subdivision among populations were markedly higher in the brooder than in the broadcast spawner. Additionally, significant subdivision for both species between systems (>100 km), and between (>10 km) or within reefs (<10 km) within systems, indicated that many reefs or reef patches are demographically independent. There was also a clear distinction in the scale of genetic structure between the different systems; at the more geographically complex of the systems, a much finer scale structure was detected in both species. This suggested that the hydrodynamics associated with these complex reefs restrict distances regularly traveled by larvae. The primary implication is that short‐term recovery of these coral communities after severe disturbance requires the input of larvae from viable communities kilometers to a few tens of kilometers away. Therefore, to be self‐sustaining, we suggest that coral reef protected areas need to be large enough to encompass these routine dispersal distances. Further, to facilitate recovery from severe disturbances, protected areas need to be replicated over these spatial scales. However, specific designs also need to account for size, complexity, and isolation of reefs, which will either restrict or enhance dispersal within this range.
Drawbacks of complex models in frequentist and Bayesian approaches to natural‐resource management
Authors: Adkison Milo D.
Published: February 2009

Previous studies have shown that, for managing harvest of natural resources, overly complex models perform poorly. Decision‐analytic approaches treat uncertainly differently from the maximum‐likelihood approaches these studies employed. By simulation using a simple fisheries model, I show that decision‐analytic approaches to managing harvest also can suffer from using overly complex models. Managers using simpler models can outperform managers using more complex models, even if the more complex models are correct and even if their use allows the incorporation of additional relevant information. Decision‐analytic approaches outperformed maximum‐likelihood approaches in my simulations, even when Bayesian priors were uninformative.
Indigenous ancestral sayings contribute to modern conservation partnerships: examples using Phormium tenax
Authors: Wehi Priscilla M.
Published: February 2009

Traditional ecological knowledge (TEK) is central to indigenous worldviews and practices and is one of the most important contributions that indigenous people can bring to conservation management partnerships. However, researchers and managers may have difficulty accessing such knowledge, particularly where knowledge transmission has been damaged. A new methodological approach analyzes ancestral sayings from Maori oral traditions for ecological information about Phormium tenax, a plant with high cultural value that is a dominant component in many threatened wetland systems, and frequently used in restoration plantings in New Zealand. Maori ancestral sayings record an association with nectar‐feeding native parrots that has only rarely been reported, as well as indications of important environmental parameters (rainfall and drought) for this species. These sayings provide evidence of indigenous management that has not been reported from interviews with elders, including evidence of fire use to create Phormium cultivations. TEK in Maori ancestral sayings imply landscape‐scale processes in comparison to intensive, small‐scale management methods often reported in interviews. TEK in ancestral sayings can be used to generate new scientific hypotheses, negotiate collaborative pathways, and identify ecological management strategies that support biodiversity retention. TEK can inform restoration ecology, historical ecology, and conservation management of species and ecosystems, especially where data from pollen records and archaeological artifacts are incomplete.
Carbon dynamics of Oregon and Northern California forests and potential land‐based carbon storage
Authors: Hudiburg Tara , Law Beverly , Turner David P. , Campbell John , Donato Dan , Duane Maureen
Published: February 2009

Net uptake of carbon from the atmosphere (net ecosystem production, NEP) is dependent on climate, disturbance history, management practices, forest age, and forest type. To improve understanding of the influence of these factors on forest carbon stocks and flux in the western United States, federal inventory data and supplemental field measurements at additional plots were used to estimate several important components of the carbon balance in forests in Oregon and Northern California during the 1990s. Species‐ and ecoregion‐specific allometric equations were used to estimate live and dead biomass stores, net primary productivity (NPP), and mortality. In the semiarid East Cascades and mesic Coast Range, mean total biomass was 8 and 24 kg C/m2, and mean NPP was 0.30 and 0.78 kg C·m−2·yr−1, respectively. Maximum NPP and dead biomass stores were most influenced by climate, whereas maximum live biomass stores and mortality were most influenced by forest type. Within ecoregions, mean live and dead biomass were usually higher on public lands, primarily because of the younger age class distribution on private lands. Decrease in NPP with age was not general across ecoregions, with no marked decline in old stands (>200 years old) in some ecoregions. In the absence of stand‐replacing disturbance, total landscape carbon stocks could theoretically increase from 3.2 ± 0.34 Pg C to 5.9 ± 1.34 Pg C (a 46% increase) if forests were managed for maximum carbon storage. Although the theoretical limit is probably unattainable, given the timber‐based economy and fire regimes in some ecoregions, there is still potential to significantly increase the land‐based carbon storage by increasing rotation age and reducing harvest rates.
Sample selection bias and presence‐only distribution models: implications for background and pseudo‐absence data
Authors: Phillips Steven J. , Dudík Miroslav , Elith Jane , Graham Catherine H. , Lehmann Anthony , Leathwick John , Ferrier Simon
Published: February 2009

Most methods for modeling species distributions from occurrence records require additional data representing the range of environmental conditions in the modeled region. These data, called background or pseudo‐absence data, are usually drawn at random from the entire region, whereas occurrence collection is often spatially biased toward easily accessed areas. Since the spatial bias generally results in environmental bias, the difference between occurrence collection and background sampling may lead to inaccurate models. To correct the estimation, we propose choosing background data with the same bias as occurrence data. We investigate theoretical and practical implications of this approach. Accurate information about spatial bias is usually lacking, so explicit biased sampling of background sites may not be possible. However, it is likely that an entire target group of species observed by similar methods will share similar bias. We therefore explore the use of all occurrences within a target group as biased background data. We compare model performance using target‐group background and randomly sampled background on a comprehensive collection of data for 226 species from diverse regions of the world. We find that target‐group background improves average performance for all the modeling methods we consider, with the choice of background data having as large an effect on predictive performance as the choice of modeling method. The performance improvement due to target‐group background is greatest when there is strong bias in the target‐group presence records. Our approach applies to regression‐based modeling methods that have been adapted for use with occurrence data, such as generalized linear or additive models and boosted regression trees, and to Maxent, a probability density estimation method. We argue that increased awareness of the implications of spatial bias in surveys, and possible modeling remedies, will substantially improve predictions of species distributions.