bluuebunny/crossref_metadata_2025 huggingface dataset:
A Top-Down Approach to Identification and Documentation of Critical Accounting Application Controls
Authors: Turner Jerry L.
Published: February 2008

SUMMARY: PCAOB Auditing Standard No. 5 prescribes assessing internal controls over financial reporting using a “top-down” approach. This paper describes a method for documenting internal controls that aligns the documentation for application controls to the overall top-down audit approach. This method identifies critical data flow paths by beginning with the general ledger and tracing data backward (down) through the system to its origin, effectively focusing on the critical data repositories in the financial reporting process. It also directs attention to the processes that affect critical financial data and to where controls related to those processes should exist based on management assertions about financial statement account balances. The approach is both more efficient and effective than traditional bottom-up documentation approaches.
SOX Doomsday Predictions in Hindsight: Evidence from Delistings
Authors: Austen Lizabeth A. , Dickins Denise
Published: February 2008

Once the enactment of the Sarbanes-Oxley Act of 2002 (SOX) became imminent, many companies protested that complying with SOX provisions was too onerous and costly and would result in many companies choosing to withdraw from public trading. We investigate whether these doomsday predictions were well-founded based on a review of SEC Form 15 requests to delist and related news releases during the period 2002 to 2004. Our findings suggest that there has not been a significant increase in the number of requests to delist since the enactment of SOX. Furthermore, we find that of companies that delist, relatively few (4.7 percent) attribute their delisting to SOX. Companies that did attribute their delisting to SOX were smaller and less likely to be audited by Big 4 auditors, characteristics that have been previously found to be associated with poorer financial reporting quality.
Audit Partner Rotation: Evidence of Changes in Audit Partner Tenure as the Result of Mandatory Regulation in Australia
Authors: Ryken Kirsty , Radich Renee , Fargher Neil L.
Published: February 2008

SYNOPSIS: This study examines rotation practices before and after the implementation of mandatory audit partner rotation policies in Australia. We focus on the incidence of long partner tenure. Despite prior voluntary rotation practices, the results suggest that: the introduction of mandatory rules in 2003 significantly reduced the incidence of long partner tenure; auditors in locations outside Australia’s three major cities are likely to have longer audit partner tenure than those located in the major cities; and there is evidence of the differential impact of mandatory audit partner rotation on smaller audit firms. Future research could examine the need for reasonable exemptions to mandatory rotation requirements given the higher costs of partner rotation to smaller audit firms and to firms in remote locations.
XBRL: Opportunities and Challenges in Enhancing Financial Reporting and Assurance Processes
Authors: Gunn James
Published: February 2008

This paper describes some of the benefits and opportunities in relation to the use of XBRL, as it exists today, from a domestic (U.S.) and international perspective, as well as some possible challenges to its widespread adoption and acceptance. Additionally, this paper discusses what specifically XBRL means for accountants in business (e.g., business management), public practice, or academia, those involved in the development of assurance services, and users of financial information.
Asian Indians Have Enhanced Skeletal Muscle Mitochondrial Capacity to Produce ATP in Association With Severe Insulin Resistance
Authors: Nair K. Sreekumaran , Bigelow Maureen L. , Asmann Yan W. , Chow Lisa S. , Coenen-Schimke Jill M. , Klaus Katherine A. , Guo Zeng-Kui , Sreekumar Raghavakaimal , Irving Brian A.
Published: February 2008

OBJECTIVE— Type 2 diabetes has become a global epidemic, and Asian Indians have a higher susceptibility to diabetes than Europeans. We investigated whether Indians had any metabolic differences compared with Northern European Americans that may render them more susceptible to diabetes.

RESEARCH DESIGN AND METHODS— We studied 13 diabetic Indians, 13 nondiabetic Indians, and 13 nondiabetic Northern European Americans who were matched for age, BMI, and sex. The primary comparisons were insulin sensitivity by hyperinsulinemic-euglycemic clamp and skeletal muscle mitochondrial capacity for oxidative phosphorylation (OXPHOS) by measuring mitochondrial DNA copy number (mtDNA), OXPHOS gene transcripts, citrate synthase activity, and maximal mitochondrial ATP production rate (MAPR). Other factors that may cause insulin resistance were also measured.

RESULTS— The glucose infusion rates required to maintain identical glucose levels during the similar insulin infusion rates were substantially lower in diabetic Indians than in the nondiabetic participants (P < 0.001), and they were lower in nondiabetic Indians than in nondiabetic Northern European Americans (P < 0.002). mtDNA (P < 0.02), OXPHOS gene transcripts (P < 0.01), citrate synthase, and MAPR (P < 0.03) were higher in Indians irrespective of their diabetic status. Intramuscular triglyceride, C-reactive protein, interleukin-6, and tumor necrosis factor-α concentrations were higher, whereas adiponectin concentrations were lower in diabetic Indians.

CONCLUSIONS— Despite being more insulin resistant, diabetic Indians had similar muscle OXPHOS capacity as nondiabetic Indians, demonstrating that diabetes per se does not cause mitochondrial dysfunction. Indians irrespective of their diabetic status had higher OXPHOS capacity than Northern European Americans, although Indians were substantially more insulin resistant, indicating a dissociation between mitochondrial dysfunction and insulin resistance.
Peroxynitrite Mediates Retinal Neurodegeneration by Inhibiting Nerve Growth Factor Survival Signaling in Experimental and Human Diabetes
Authors: Ali Tayyeba K. , Matragoon Suraporn , Pillai Bindu A. , Liou Gregory I. , El-Remessy Azza B.
Published: February 2008

OBJECTIVE—Recently we have shown that diabetes-induced retinal neurodegeneration positively correlates with oxidative stress and peroxynitrite. Studies also show that peroxynitrite impairs nerve growth factor (NGF) survival signaling in sensory neurons. However, the causal role of peroxynitrite and the impact of tyrosine nitration on diabetes-induced retinal neurodegeneration and NGF survival signaling have not been elucidated.

RESEARCH DESIGN AND METHODS—Expression of NGF and its receptors was examined in retinas from human and streptozotocin-induced diabetic rats and retinal ganglion cells (RGCs). Diabetic animals were treated with FeTPPS (15 mg · kg−1 · day−1 ip), which catalytically decomposes peroxynitrite to nitrate. After 4 weeks of diabetes, retinal cell death was determined by TUNEL assay. Lipid peroxidation and nitrotyrosine were determined using MDA assay, immunofluorescence, and Slot-Blot analysis. Expression of NGF and its receptors was determined by enzyme-linked immunosorbent assay (ELISA), real-time PCR, immunoprecipitation, and Western blot analyses.

RESULTS—Analyses of retinal neuronal death and NGF showed ninefold and twofold increases, respectively, in diabetic retinas compared with controls. Diabetes also induced increases in lipid peroxidation, nitrotyrosine, and the pro-apoptotic p75NTR receptor in human and rat retinas. These effects were associated with tyrosine nitration of the pro-survival TrkA receptor, resulting in diminished phosphorylation of TrkA and its downstream target, Akt. Furthermore, peroxynitrite induced neuronal death, TrkA nitration, and activation of p38 mitogen-activated protein kinase (MAPK) in RGCs, even in the presence of exogenous NGF. FeTPPS prevented tyrosine nitration, restored NGF survival signal, and prevented neuronal death in vitro and in vivo.

CONCLUSIONS—Together, these data suggest that diabetes-induced peroxynitrite impairs NGF neuronal survival by nitrating TrkA receptor and enhancing p75NTR expression.
Raising the Bar: Curricular Intensity and Academic Performance
Authors: Attewell Paul , Domina Thurston
Published: February 2008

Using national transcript data, the authors examine inequality in access to an advanced curriculum in high school and assess the consequences of curricular intensity on test scores and college entry. Inequalities in curricular intensity are primarily explained by student socioeconomic status effects that operate within schools rather than between schools. They find significant positive effects of taking a more intense curriculum on 12th-grade test scores and in probabilities of entry to and completion of college. However, the effect sizes of curricular intensity are generally modest, smaller than advocates of curricular upgrading policies have implied.
X‐LRT: a likelihood approach to estimate genetic risks and test association with X‐linked markers using a case‐parents design
Authors: Zhang Li , Martin Eden R. , Chung Ren‐Hua , Li Yi‐Ju , Morris Richard W.
Published: February 2008

Recently, there has been interest in family‐based tests of association to identify X‐chromosome genes. However, none of the approaches allow for estimation of genetic risks. We propose a likelihood approach to estimate disease‐related marker relative risks and test genotype association using a case‐parents design. The test uses nuclear families with a single affected proband and allows additional siblings and missing parental genotypes. Extension to a haplotype test is based on assumptions of random mating and multiplicative penetrance. We investigate power and type I error rate of the likelihood‐based test, using simulated data and apply our method to marker data from the monoamine oxidase A&B genes in families with Parkinson disease. We show how efficiency with missing parental information can be improved with additional sibling genotype information. Our likelihood approach offers great flexibility for testing different penetrance relationships within and between sexes. In addition, estimation of disease‐related marker relative risks provides a measure of the magnitude of X‐linked genetic effects on complex disorders.Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
Power of transmission/disequilibrium tests in admixed populations
Authors: Li Miao‐Xin , Jiang Lin , Song You‐Qiang , Sham Pak C.
Published: February 2008

The power of transmission/disequilibrium tests (TDTs) for detecting disease susceptibility loci is expected to be influenced by population admixture through its impact on the degree of linkage disequilibrium (LD) between the genetic marker and the DSL. However, few studies have been done to systematically examine this behavior of the TDTs in admixed populations. In the present study, extensive computer simulations were conducted to explore how population admixture affects the power of TDTs. It was found that (1) in newly admixed populations, the LD due to admixture makes no contribution to the power of TDTs, and it is the averaged background LD in the parental populations that determines the power of TDTs; but (2) after random mating between the admixed populations, the LD due to admixture becomes effective in increasing or decreasing the power of the tests, and (3) incomplete random mating can prolong the time for the LD due to admixture to become effective. This study clarifies the potential influence of population admixture on the performance of TDTs. Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
In situ high-pressure x-ray diffraction study of H2O ice VII
Authors: Somayazulu Maddury , Shu Jinfu , Zha Chang-sheng , Goncharov Alexander F. , Tschauner Oliver , Mao Ho-kwang , Hemley Russell J.
Published: February 2008

Ice VII was examined over the entire range of its pressure stability by a suite of x-ray diffraction techniques in order to understand a number of unexplained characteristics of its high-pressure behavior. Axial and radial polycrystalline (diamond anvil cell) x-ray diffraction measurements reveal a splitting of diffraction lines accompanied by changes in sample texture and elastic anisotropy. In situ laser heating of polycrystalline samples resulted in the sharpening of diffraction peaks due to release of nonhydrostatic stresses but did not remove the splitting. Radial diffraction measurements indicate changes in strength of the material at this pressure. Taken together, these observations provide evidence for a transition in ice VII near 14GPa involving changes in the character of the proton order/disorder. The results are consistent with previous reports of changes in phase boundaries and equation of state at this pressure. The transition can be interpreted as ferroelastic with the appearance of spontaneous strain that vanishes at the hydrogen bond symmetrization transition near 60GPa.
The state averaged multiconfigurational time-dependent Hartree approach: Vibrational state and reaction rate calculations
Authors: Manthe Uwe
Published: February 2008

The multiconfigurational time-dependent Hartree (MCTDH) approach uses optimized sets of time-dependent basis functions, called single-particle functions, to represent multidimensional wavefunctions and thereby facilitates efficient multidimensional quantum dynamics studies. The single-particle function bases are usually optimized for a single wavefunction. Here, an approach is studied which utilizes a common single-particle function basis to represent several wavefunctions simultaneously, i.e., the single-particle function basis is constructed to result in an optimized averaged description of a number of wavefunctions. The approach can favorably be used to obtain eigenstates of Hamiltonians or to represent thermal ensembles. Test calculations studying the vibrational states of CH3 and the thermal rate constant of the H+CH4→H2+CH3 reaction are presented. It is found that the required size of the single-particle functions basis does not increase when the number of wavefunctions described simultaneously is increased. As a consequence, the new approach offers an increased efficiency, e.g., for MCTDH rate constant calculations.
Depolarization effect in reflection-mode tip-enhanced Raman scattering for Raman active crystals
Authors: Motohashi Masashi , Hayazawa Norihiko , Tarun Alvarado , Kawata Satoshi
Published: February 2008

Reflection-mode tip-enhanced Raman scattering (TERS) has the advantage to characterize any sample, particularly opaque, bulk, and multilayered samples. However, the background signal in reflection-mode TERS is huge due to large focus spots associated with an objective lens that has a long working distance. Moreover, for a multilayered and bulk sample, the Raman signal from the bulk layer interferes with the Raman signal on a thin surface layer. This unwanted bulk background signal reduces the sensitivity of the measurement and makes it difficult to get a high-contrast TERS image in the reflection mode. Here, we demonstrate two techniques to suppress the far-field Raman signals coming from the focus area and bulk silicon germanium substrate. First, we reduce the far-field signal by controlling the polarization state of the incident and scattered Raman as well as manipulating the well-defined polarization of a crystalline sample, which strongly depends on the polarization and propagation of the incident light. We used Raman tensor analysis to quantify the far-field Raman intensity at different polarization states of the polarizer and analyzer at varying sample azimuth. The results of the surface-enhanced Raman spectroscopy experiments were in good agreement with the far-field Raman tensor calculation. The polarizer, analyzer, and sample azimuth combination that gives minimum far-field background signals with high contrast in SERS was utilized in the TERS experiment to obtain a high-contrast near-field Raman signal. Both the field enhancement effect and depolarized detection were considered to obtain a high signal-to-noise TERS signal. We found that, for Raman active and thin crystalline samples assembled in bulk materials, the depolarization effect outweighs the field enhancement effect in getting a high-contrast Raman signal.
Film thickness dependence of electrocaloric effect in epitaxial Ba0.6Sr0.4TiO3 thin films
Authors: Qiu J. H. , Jiang Q.
Published: February 2008

Based on the phenomenological Landau–Devonshire thermodynamic theory, the film thickness dependence of electrocaloric effect in epitaxial Ba0.6Sr0.4TiO3 thin films is investigated. Theoretical analysis shows that the Ba0.6Sr0.4TiO3 thin films grown on LaAlO3 and MgO substrates have the giant electrocaloric effect at room temperature. Our theoretical calculations also indicate that the entropy and electrocaloric effect strongly depend on film thickness.
Terahertz air-core microstructure fiber
Authors: Lu Ja-Yu , Yu Chin-Ping , Chang Hung-Chung , Chen Hung-Wen , Li Yu-Tai , Pan Ci-Ling , Sun Chi-Kuang
Published: February 2008

A low-loss terahertz air-core microstructure fiber is demonstrated for terahertz waveguiding. Substantially low attenuation constant less than 0.01cm−1 has been achieved and the guiding wavelength is found to be tunable by linear scaling the fiber size. The experimental results well agree with the simulation based on the finite-difference frequency-domain method, which interprets the guiding mechanism as the antiresonant reflecting waveguiding. The simulated modal pattern shows that most terahertz field is concentrated inside the central hollow air core and is guided without outside interference, which has high potential for guiding intense terahertz waves with minimized loss.
Nonvolatile memory characteristics influenced by the different crystallization of Ni–Si and Ni–N nanocrystals
Authors: Chen Wei-Ren , Chang Ting-Chang , Yeh Jui-Lung , Chang Chun-Yen , Chen Shih-Ching
Published: February 2008

The formation of Ni–Si and Ni–N nanocrystals by sputtering a Ni0.3Si0.7 target in argon and nitrogen environment were proposed in this paper. A transmission electron microscope analysis shows the nanocrystals embedded in the nitride layer. X-ray photoelectron spectroscopy and x-ray diffraction also offer the chemical material analysis of nanocrystals with surrounding dielectric and the crystallization of nanocrystals for different thermal annealing treatments. Nonvolatile Ni–Si nanocrystal memories reveal superior electrical characteristics for charge storage capacity and reliability due to the improvement of thermal annealing treatment. In addition, we used energy band diagrams to explain the significance of surrounding dielectric for reliability.
Lateral length scales of latent image roughness as determined by off-specular neutron reflectivity
Authors: Lavery Kristopher A. , Prabhu Vivek M. , Lin Eric K. , Wu Wen-li , Satija Sushil K. , Choi Kwang-Woo , Wormington Matthew
Published: February 2008

A combination of specular and off-specular neutron reflectometries was used to measure the buried lateral roughness of the reaction-diffusion front in a model extreme ultraviolet lithography photoresist. Compositional heterogeneities at the latent reaction-diffusion front has been proposed as a major cause of line edge roughness in photolithographic features. This work describes the experimental observation of the longitudinal and lateral compositional heterogeneities of a latent image, revealing the buried lateral length scale as well as the amplitude of inhomogeneity at the reaction-diffusion front. These measurements aid in determining the origins of line edge roughness formation, while exploring the material limits of the current chemically amplified photoresists.
Time resolved magneto-optical studies of ferromagnetic InMnSb films
Authors: Frazier M. , Kini R. N. , Nontapot K. , Khodaparast G. A. , Wojtowicz T. , Liu X. , Furdyna J. K.
Published: February 2008

We report time resolved magneto-optical measurements in InMnSb ferromagnetic films with 2% and 2.8% Mn contents grown by low temperature molecular beam epitaxy. In order to probe a possible interaction between the spins of photoexcited carriers and the Mn ions, we measured spin dynamics before and after aligning the Mn ions by applying an external magnetic field at temperatures above and below the samples’ Curie temperatures. We observed no significant temperature or magnetic field dependence in the relaxation times and attribute the observed dynamics entirely to the relaxation of photoexcited electrons in the conduction band where the s-d coupling with the localized Mn ions is significantly weaker compared to the p-d exchange coupling. We observed several differences in the optical response of our InMnSb samples which could have been influenced mainly by the samples’ growth conditions.
High-performance carbon nanotube network transistors for logic applications
Authors: Chiu Po-Wen , Chen Chien-Hua
Published: February 2008

We report on the fabrication of carbon nanotube network field effect transistors, in which a submonolayer network is selectively and uniformly dispersed in the active region with individually addressable back gate. The high current on/off ratio (104) and good device-to-device uniformity were achieved by selective burnout of metallic pathways. The enhanced capacitive coupling between the gate and nanotube network reduces the subthreshold slope down to 180mV∕dec. The effective local gating allows us to implement logic circuits, such as an inverter and the two most important universal NOR and NAND gates.
Optical magnetoelectric effect at CaRuO3–CaMnO3 interfaces as a polar ferromagnet
Authors: Yamada Hiroyuki , Sato H. , Akoh H. , Kida N. , Arima T. , Kawasaki M. , Tokura Y.
Published: February 2008

A correlated electron interface between paramagnetic CaRuO3 and antiferromagnetic CaMnO3 has been characterized with optical magnetoelectric (OME) effect as an interface-selective probe for spin and charge states. To detect the OME effect, i.e., nonreciprocal directional dichroism for visible or near-infrared light, we have constructed a “tricolor” superlattice with artificially broken inversion symmetry by stacking CaRuO3, CaMnO3, and CaTiO3, and patterned a grating structure with 4μm period on the superlattice. The observed intensity modulation (0.3% at 50K) in the Bragg diffraction verifies a charge transfer and concomitant ferromagnetism at the CaRuO3–CaMnO3 interface.
Spin reorientation transition of ferromagnetic nanowires with perpendicular magnetic anisotropy
Authors: Choe Sug-Bong
Published: February 2008

We present an analytic theory of the magnetization phase in ferromagnetic nanowires with perpendicular magnetic anisotropy. In nanowire geometry, the shape anisotropy is reduced considerably in contrast to continuous films. Consequently, the spin reorientation transition occurs from in plane to out of plane with respect to the wire width. The stable domain size in the out-of-plane phase is sensitive to the wire width and approaches the single domain state on narrowing the width further. A phase diagram of the three phases is proposed with respect to the wire width and the saturation magnetization.
Noise suppression by active optics in low-dose electron microscopy
Authors: Okamoto Hiroshi
Published: February 2008

Low-dose electron microscopy of radiation sensitive biological specimens achieves only limited resolution because of the inherently weak signal buried in noise. Here, we propose to reduce the noise by using a deformable mirror similar to the Castaing–Henry device to manipulate phase of the electron waves. The method takes advantage of quantum nature of the measurement and nonrandomness of any specimen structure of interest. The simulation revealed 9.7% reduction of noise for the representative case of the ribosome. Increasingly better figures are expected as knowledge about a specimen improves.
Electrical tuning of birefringence in silicon waveguides
Authors: Tsia K. K. , Fathpour S. , Jalali B.
Published: February 2008

We demonstrate dynamic control of the birefringence in a silicon waveguide. Electrically tunable stress on the waveguide core is induced using an integrated piezoelectric film. We show that the induced birefringence can be used to fine tune the phase mismatch among interacting waves present in parametric nonlinear optical effects.
Aligned three-dimensional prismlike magnesium nanostructures realized onto silicon substrate
Authors: Zhang Kaili , Rossi Carole , Tenailleau Christophe , Alphonse Pierre
Published: February 2008

A simple approach is proposed to realize three-dimensional (3D) prismlike Mg nanostructures, which has several advantages over previous investigations such as suitable for mass production, reduced impurities, tailored dimensions, and easier integration into microsystem. 3D Mg nanostructures are realized onto silicon substrate using a conventional thermal evaporator, where the incident angle of Mg vapor flux with respect to the substrate surface normal is fixed at 88°. The as-prepared 3D Mg nanostructures are characterized by scanning electron microscopy, x-ray diffraction, energy dispersive x-ray analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and surface area measurement.
Platinum thin film–antimony doped barium strontium titanate Schottky barrier diode
Authors: Sirikulrat N.
Published: February 2008

The Schottky barrier diode of the platinum thin film on the antimony doped barium strontium titanate polycrystalline ceramics was prepared and its electrical conduction was investigated. At the low field forward biasing, the current voltage relationship was Ohmic as expected from the space charge limited conduction (SCLC). Results from the high field biasing indicated that the exponential conduction occurred due to the Schottky emission rather than the trap free square law arising from the SCLC. The barrier height and the ideality factor of 0.87eV and 1.5 were obtained in the diode with the Pt film thickness of 84nm.
Evidence of female cryptic choice in crayfish
Authors: Aquiloni Laura , Gherardi Francesca
Published: February 2008

To test whether male body size affects female reproductive investment in the polygamous crayfishProcambarus clarkii, we described mating behaviour of virgin females paired with either small or large males, and analysed the number, size and weight of both eggs and juveniles sired by either types of male. Along with confirming the overt selection by females of larger mates, we found that the size and weight of both the eggs and the juveniles were higher when sired by larger fathers. This suggests thatP. clarkiifemales exert a form of cryptic choice for large males, seemingly adjusting the quantity of egg deutoplasm in function of the mate body size. The question of why females spend time and energy to brood low-fitness offspring is finally raised.
Introduced delicacy or native species? A natural origin of Bermudian terrapins supported by fossil and genetic data
Authors: Parham James F , Outerbridge Mark E , Stuart Bryan L , Wingate David B , Erlenkeuser Helmut , Papenfuss Theodore J
Published: February 2008

Humans have greatly altered the natural distribution of species, making it difficult to distinguish between natural and introduced populations. This is a problem for conservation efforts because native or introduced status can determine whether a species is afforded protection or persecuted as an invasive pest. Holocene colonization events are especially difficult to discern, particularly when the species in question is a naturally good disperser and widely transported by people. In this study, we test the origin of such a species, the diamondback terrapin (
Malaclemys terrapin
), on Bermuda using a combination of palaeontologic (fossil, radiometric and palaeoenvironmental) and genetic data. These lines of evidence support the hypothesis that terrapins are relatively recent (between 3000 and 400 years ago) natural colonizers of Bermuda. The tiny population of Bermudian terrapins represents the second naturally occurring non-marine reptile that still survives on one of the most densely populated and heavily developed oceanic islands in the world. We recommend that they should be given protection as a native species.
Candidate gene microsatellite variation is associated with parasitism in wild bighorn sheep
Authors: Luikart Gordon , Pilgrim Kristy , Visty Judy , Ezenwa Vanessa O , Schwartz Michael K
Published: February 2008

The loss of genetic variation in host populations is thought to increase host susceptibility to parasites. However, few data exist to test this hypothesis in natural populations. Bighorn sheep (
Ovis canadensis
) populations occasionally suffer disease-induced population declines, allowing us to test for the associations between reduced genetic variation and parasitism in this species. Here, we show that individual mean heterozygosity for 15 microsatellite loci is associated with lungworm abundance (
Protostrongylus
spp.) in a small, recently bottlenecked population of bighorn sheep (linear regression,
r
2
=0.339,
p
=0.007). This association remains significant for seven microsatellites located in genes (
p
=0.010), but not for eight neutral microsatellites (
p
=0.306). Furthermore, heterozygotes at three of four microsatellites located within disease-related genes had lower lungworm burdens. This study corroborates theoretical findings that increased parasitism and disease may be a consequence of reduced heterozygosity in wild populations, and that certain individual loci influence parasite resistance. The results illustrate the usefulness of using genomic information, strong candidate genes and non-invasive sampling for monitoring both genetic variation and fitness-related traits, such as parasite resistance, in natural populations.
Higher order asymptotic homogenization and wave propagation in periodic composite materials
Authors: Andrianov Igor V , Bolshakov Vladimir I , Danishevs'kyy Vladyslav V , Weichert Dieter
Published: February 2008

We present an application of the higher order asymptotic homogenization method (AHM) to the study of wave dispersion in periodic composite materials. When the wavelength of a travelling signal becomes comparable with the size of heterogeneities, successive reflections and refractions of the waves at the component interfaces lead to the formation of a complicated sequence of the pass and stop frequency bands. Application of the AHM provides a long-wave approximation valid in the low-frequency range. Solution for the high frequencies is obtained on the basis of the Floquet–Bloch approach by expanding spatially varying properties of a composite medium in a Fourier series and representing unknown displacement fields by infinite plane-wave expansions. Steady-state elastic longitudinal waves in a composite rod (one-dimensional problem allowing the exact analytical solution) and transverse anti-plane shear waves in a fibre-reinforced composite with a square lattice of cylindrical inclusions (two-dimensional problem) are considered. The dispersion curves are obtained, the pass and stop frequency bands are identified.
Management of drug resistance in the population: influenza as a case study
Authors: Moghadas Seyed M
Published: February 2008

The rise of drug resistance remains a major impediment to the treatment of some diseases caused by fast-evolving pathogens that undergo genetic mutations. Models describing the within-host infectious dynamics suggest that the resistance is unlikely to emerge if the pathogen-specific immune responses are maintained above a certain threshold during therapy. However, emergence of resistance in the population involves both within-host and between-host infection mechanisms. Here, we employ a mathematical model to identify an effective treatment strategy for the management of drug resistance in the population. We show that, in the absence of pre-existing immunity, the population-wide spread of drug-resistant pathogen strains can be averted if a sizable portion of susceptible hosts is depleted before drugs are used on a large scale. The findings, based on simulations for influenza infection as a case study, suggest that the initial prevalence of the drug-sensitive strain under low pressure of drugs, followed by atimelyimplementation of intensive treatment, can minimize the total number of infections while preventing outbreaks of drug-resistant infections.
Genetic variation and covariation of susceptibility to parasitoids in the aphid
Myzus persicae
: no evidence for trade-offs
Authors: von Burg Simone , Ferrari Julia , Müller Christine B , Vorburger Christoph
Published: February 2008

Parasitoids are an important mortality factor for insects. Susceptibility to parasitoids should thus be under strong negative selection. Nevertheless, ample genetic variation for susceptibility to parasitoids is commonly observed in natural populations, suggesting that trade-offs may constrain the evolution of reduced susceptibility. This can be studied by assessing genetic variation for susceptibility and its covariation with other components of fitness. In a set of 17 clones of the peach potato aphid,
Myzus persicae
, for which good estimates of heritable variation for life-history traits were available, we found significant clonal variation for susceptibility to two of their common parasitoids:
Aphidius colemani
and
Diaeretiella rapae
. One clone, the only one harbouring a facultative endosymbiotic bacterium,
Regiella insecticola
, was entirely resistant to both parasitoids. Susceptibilities to the two parasitoids exhibited a positive genetic correlation close to unity, implying a general mechanism of defence. However, the susceptibility to parasitoids was uncorrelated to the clones' fecundity or rate of increase, providing no evidence for costs of the ability to resist parasitoids.
Fire, climate change and biodiversity in Amazonia: a Late-Holocene perspective
Authors: Bush M.B , Silman M.R , McMichael C , Saatchi S
Published: February 2008

Fire is an important and arguably unnatural component of many wet Amazonian and Andean forest systems. Soil charcoal has been used to infer widespread human use of landscapes prior to European Conquest. An analysis of Amazonian soil carbon records reveals that the records have distinct spatial and temporal patterns, suggesting that either fires were only set in moderately seasonal areas of Amazonia or that strongly seasonal and aseasonal areas are undersampled. Synthesizing data from 300 charcoal records, an age–frequency diagram reveals peaks of fire apparently coinciding with some periods of very strong El Niño activity. However, the El Niño record does not always provide an accurate prediction of fire timing, and a better match is found in the record of insolation minima. After the time of European contact, fires became much scarcer within Amazonia. In both the Amazonia and the Andes, modern fire pattern is strongly allied to human activity. On the flank of the Andes, forests that have never burned are being eroded by fire spreading downslope from grasslands. Species of these same forests are being forced to migrate upslope due to warming and will encounter a firm artificial fire boundary of human activity.
Conservation strategies to mitigate impacts from climate change in Amazonia
Authors: Killeen Timothy J , Solórzano Luis A
Published: February 2008

Protected area systems and conservation corridors can help mitigate the impacts of climate change on Amazonian biodiversity. We propose conservation design criteria that will help species survivein situor adjust range distributions in response to increased drought. The first priority is to protect the western Amazon, identified as the ‘Core Amazon’, due to stable rainfall regimes and macro-ecological phenomena that have led to the evolution of high levels of biodiversity. Ecotones can buffer the impact from climate change because populations are genetically adapted to climate extremes, particularly seasonality, because high levels of habitat diversity are associated with edaphic variability. Future climatic tension zones should be surveyed for geomorphological features that capture rain or conserve soil moisture to identify potential refugia for humid forest species. Conservation corridors should span environmental gradients to ensure that species can shift range distributions. Riparian corridors provide protection to both terrestrial and aquatic ecosystems. Multiple potential altitudinal corridors exist in the Andes, but natural and anthropogenic bottlenecks will constrain the ability of species to shift their ranges and adapt to climate change. Planned infrastructure investments are a serious threat to the potential to consolidate corridors over the short and medium term.
Impact of a drier Early–Mid-Holocene climate upon Amazonian forests
Authors: Mayle Francis E , Power Mitchell J
Published: February 2008

This paper uses a palaeoecological approach to examine the impact of drier climatic conditions of the Early–Mid-Holocene (
ca
8000–4000 years ago) upon Amazonia's forests and their fire regimes. Palaeovegetation (pollen data) and palaeofire (charcoal) records are synthesized from 20 sites within the present tropical forest biome, and the underlying causes of any emergent patterns or changes are explored by reference to independent palaeoclimate data and present-day patterns of precipitation, forest cover and fire activity across Amazonia. During the Early–Mid-Holocene, Andean cloud forest taxa were replaced by lowland tree taxa as the cloud base rose while lowland ecotonal areas, which are presently covered by evergreen rainforest, were instead dominated by savannahs and/or semi-deciduous dry forests. Elsewhere in the Amazon Basin there is considerable spatial and temporal variation in patterns of vegetation disturbance and fire, which probably reflects the complex heterogeneous patterns in precipitation and seasonality across the basin, and the interactions between climate change, drought- and fire susceptibility of the forests, and Palaeo-Indian land use. Our analysis shows that the forest biome in most parts of Amazonia appears to have been remarkably resilient to climatic conditions significantly drier than those of today, despite widespread evidence of forest burning. Only in ecotonal areas is there evidence of biome replacement in the Holocene. From this palaeoecological perspective, we argue against the Amazon forest ‘dieback’ scenario simulated for the future.
Taking things public: a contribution to address human dimensions of environmental change
Authors: Alves Diógenes S
Published: February 2008

This paper addresses the question of environmental change in Amazônia, by looking at the experiences of the large-scale biosphere–atmosphere (LBA) experiment in the Amazon, and three other enterprises—the extractive reserves, the Pilot Programme to Conserve the Brazilian Rain Forest (PPG7) and ecological-economic zoning—that address questions of sustainable development in the region. The LBA experience shows how the integration with the social sciences can be critical for science to explore its own outcomes for society, while the other programmes expose environmental change as a problem with too many intersections within society, so the outcomes of any initiative depends on placing it before a complex, tense and wide arena.
Generating carbon finance through avoided deforestation and its potential to create climatic, conservation and human development benefits
Authors: Ebeling Johannes , Yasué Maï
Published: February 2008

Recent proposals to compensate developing countries for reducing emissions from deforestation (RED) under forthcoming climate change mitigation regimes are receiving increasing attention. Here we demonstrate that if RED credits were traded on international carbon markets, even moderate decreases in deforestation rates could generate billions of Euros annually for tropical forest conservation. We also discuss the main challenges for a RED mechanism that delivers real climatic benefits. These include providing sufficient incentives while only rewarding deforestation reductions beyond business-as-usual scenarios, addressing risks arising from forest degradation and international leakage, and ensuring permanence of emission reductions. Governance may become a formidable challenge for RED because some countries with the highest RED potentials score poorly on governance indices. In addition to climate mitigation, RED funds could help achieve substantial co-benefits for biodiversity conservation and human development. However, this will probably require targeted additional support because the highest biodiversity threats and human development needs may exist in countries that have limited income potentials from RED. In conclusion, how successfully a market-based RED mechanism can contribute to climate change mitigation, conservation and development will strongly depend on accompanying measures and carefully designed incentive structures involving governments, business, as well as the conservation and development communities.
Drought effects on litterfall, wood production and belowground carbon cycling in an Amazon forest: results of a throughfall reduction experiment
Authors: Brando Paulo M , Nepstad Daniel C , Davidson Eric A , Trumbore Susan E , Ray David , Camargo Plínio
Published: February 2008

The Amazon Basin experiences severe droughts that may become more common in the future. Little is known of the effects of such droughts on Amazon forest productivity and carbon allocation. We tested the prediction that severe drought decreases litterfall and wood production but potentially has multiple cancelling effects on belowground production within a 7-year partial throughfall exclusion experiment. We simulated an approximately 35–41% reduction in effective rainfall from 2000 through 2004 in a 1 ha plot and compared forest response with a similar control plot. Wood production was the most sensitive component of above-ground net primary productivity (ANPP) to drought, declining by 13% the first year and up to 62% thereafter. Litterfall declined only in the third year of drought, with a maximum difference of 23% below the control plot. Soil CO
2
efflux and its
14
C signature showed no significant treatment response, suggesting similar amounts and sources of belowground production. ANPP was similar between plots in 2000 and declined to a low of 41% below the control plot during the subsequent treatment years, rebounding to only a 10% difference during the first post-treatment year. Live aboveground carbon declined by 32.5 Mg ha
−1
through the effects of drought on ANPP and tree mortality. Results of this unreplicated, long-term, large-scale ecosystem manipulation experiment demonstrate that multi-year severe drought can substantially reduce Amazon forest carbon stocks.
The changing Amazon forest
Authors: Phillips Oliver L , Lewis Simon L , Baker Timothy R , Chao Kuo-Jung , Higuchi Niro
Published: February 2008

Long-term monitoring of distributed, multiple plots is the key to quantify macroecological patterns and changes. Here we examine the evidence for concerted changes in the structure, dynamics and composition of old-growth Amazonian forests in the late twentieth century. In the 1980s and 1990s, mature forests gained biomass and underwent accelerated growth and dynamics, all consistent with a widespread, long-acting stimulation of growth. Because growth on average exceeded mortality, intact Amazonian forests have been a carbon sink. In the late twentieth century, biomass of trees of more than 10 cm diameter increased by 0.62±0.23 t C ha
−1
 yr
−1
averaged across the basin. This implies a carbon sink in Neotropical old-growth forest of at least 0.49±0.18 Pg C yr
−1
. If other biomass and necromass components are also increased proportionally, then the old-growth forest sink here has been 0.79±0.29 Pg C yr
−1
, even before allowing for any gains in soil carbon stocks. This is approximately equal to the carbon emissions to the atmosphere by Amazon deforestation. There is also evidence for recent changes in Amazon biodiversity. In the future, the growth response of remaining old-growth mature Amazon forests will saturate, and these ecosystems may switch from sink to source driven by higher respiration (temperature), higher mortality (as outputs equilibrate to the growth inputs and periodic drought) or compositional change (disturbances). Any switch from carbon sink to source would have profound implications for global climate, biodiversity and human welfare, while the documented acceleration of tree growth and mortality may already be affecting the interactions among millions of species.
Better RED than dead: paying the people for environmental services in Amazonia
Authors: Hall Anthony
Published: February 2008

The introduction of payments for environmental services (PES) offers an opportunity for traditional and indigenous populations to be compensated for contributing to carbon sequestration in meeting the challenge of ameliorating global warming. As one mechanism among several for promoting biodiversity conservation and sustainable development, pro-poor PES initiatives could eventually be incorporated into an international post-Koyoto framework to encourage reduced emissions from deforestation. Brazil's
Proambiente
PES scheme for small farmers in Amazonia has enjoyed some limited success, but it has fallen short of expectations. Its performance has been undermined by the lack of a national legal framework, limited funding, reduced implementation capacity, poor cross-sector collaboration and incompatibility with existing regional development policies. These challenges are being addressed by the federal government in cooperation with civil society with a view to scaling up
Proambiente
into a national programme.
Environmental policy-making networks and the future of the Amazon
Authors: Lemos Maria Carmen , Roberts J. Timmons
Published: February 2008

This article examines four periods of environmental policy-making in the Amazon region of Brazil. It specifically analyses the role of pro-environment and pro-development policy networks in affecting policy design and implementation. It argues that the efforts of environmentalist networks trying to advocate or block relative developmentalist policies in the Amazon depend on three critical factors—whether they are able to attract the support of elites (or at least block their developmentalist policy initiatives); the type and level of international support they have; and the organizational and financial resources that they are able to mobilize. In analysing the four periods, this article finds that while international influences and resources have been substantial in enabling environmentalist networks to flourish and influence the policy, their effectiveness has been nearly always outweighed by Brazilian developmentalist interests. The outcome in each phase has been a different form of
stalemate
on environmental protection, and the deforestation continued each time, albeit at slower rates. These findings suggest that the key for significantly lower rates of deforestation on the Amazon may be in the ability of pro-environment networks to neutralize opposition by creating an incentive structure that ‘compensates’ potential losers of policies that promote conservation.