bluuebunny/crossref_metadata_2025 huggingface dataset:
ISOLATING A MEASURE OF INFLATION EXPECTATIONS FOR THE SOUTH AFRICAN FINANCIAL MARKET USING FORWARD INTEREST RATES
Authors: Reid Monique
Published: September 2009

The inflation expectations channel of the transmission mechanism is generally recognised as crucial for the implementation of modern monetary policy. This paper briefly reviews the practices commonly employed for measuring inflation expectations in South Africa, and offers an additional method, which is market based. The methodologies of Nelson and Siegel and Svensson are applied to determine implied nominal and real forward interest rates. The difference between the nominal and real forward rates (called inflation compensation) on a particular day is then used as a proxy for the market's inflation expectations. This measure should not be viewed as a substitute for other measures of inflation expectations, but should rather supplement these in order to offer an additional insight.
TESTING FOR PPP USING SADC REAL EXCHANGE RATES
Authors: Mokoena Thabo M. , Gupta Rangan , Van Eyden Reneé
Published: September 2009

This paper attempts to provide evidence indicating that the purchasing power parity (PPP) puzzle is becoming less of a puzzle. It present the results of Augmented Dickey–Fuller test, non‐linear tests of non‐stationarity and Bayesian unit root tests, applied to 10 Southern African Development Community countries. The Bayesian tests were found to be biased in favour of a trend stationary model in all cases. It is argued that non‐linear approaches to exchange rate adjustments are likely to provide a firmer basis for inference and stronger support for the PPP in the long‐term. This is more so at 1 and 5% levels of significance.
Experimental Investigation of a Large-Scale Composite Riser Tube Under External Pressure
Authors: Ramirez Guillermo , Engelhardt Michael D.
Published: September 2009

A collapse pressure test was conducted on a full-scale diameter prototype composite offshore drilling riser. The test specimen was a carbon fiber-epoxy filament-wound tube, approximately 56.4 cm outside diameter and 3.05 cm wall thickness. The tube was subjected to external water pressure up to collapse. The purpose of the test was to confirm the external pressure capacity of the specimen and to provide a basis for verification and calibration of analytical estimates of the collapse pressure of large scale carbon fiber tubes. The specimen was instrumented with strain gauges on both the outside and inside walls of the tube. This paper describes the test specimen and presents key results of the test.
Detection and Sizing of Defects in Complex Geometry Weld by Manual Ultrasonic Time of Flight Diffraction Inspection
Authors: Nath S. K. , Balasubramaniam Krishnan , Krishnamurthy C. V. , Narayana B. H.
Published: September 2009

The basic aim of this current research is to reliably detect and size defects in complex geometry welds using the well-known ultrasonic time of flight diffraction (TOFD) technique. A complex geometry weld specimen with various artificial defects was designed and fabricated. Different combinations of probe angles and probe center spacings were used in experiments for determining the optimum one. TOFD models were also developed for sizing the defects and experimentally verified.
Developing New Cast Austenitic Stainless Steels With Improved High-Temperature Creep Resistance
Authors: Maziasz Philip J. , Shingledecker John P. , Evans Neal D. , Pollard Michael J.
Published: September 2009

Oak Ridge National Laboratory and Caterpillar (CAT) have recently developed a new cast austenitic stainless steel, CF8C-Plus, for a wide range of high-temperature applications, including diesel exhaust components and turbine casings. The creep-rupture life of the new CF8C-Plus is over ten times greater than that of the standard cast CF8C stainless steel, and the creep-rupture strength is about 50–70% greater. Another variant, CF8C-Plus Cu/W, has been developed with even more creep strength at 750–850°C. The creep strength of these new cast austenitic stainless steels is close to that of wrought Ni-based superalloys such as 617. CF8C-Plus steel was developed in about 1.5 years using an “engineered microstructure” alloy development approach, which produces creep resistance based on the formation of stable nanocarbides (NbC), and resistance to the formation of deleterious intermetallics (sigma, Laves) during aging or service. The first commercial trial heats (227.5 kg or 500 lb) of CF8C-Plus steel were produced in 2002, and to date, over 27,215 kg (300 tons) have been produced, including various commercial component trials, but mainly for the commercial production of the Caterpillar regeneration system (CRS). The CRS application is a burner housing for the on-highway heavy-duty diesel engines that begins the process to burn-off particulates trapped in the ceramic diesel particulate filter (DPF). The CRS/DPF technology was required to meet the new more stringent emissions regulations in January, 2007, and subjects the CRS to frequent and severe thermal cycling. To date, all CF8C-Plus steel CRS units have performed successfully. The status of testing for other commercial applications of CF8C-Plus steel is also summarized.
Combined Effects of Tube Projection, Initial Tube-Tubesheet Clearance, and Tube Material Strain Hardening on Rolled Joint Strength
Authors: Merah N. , Al-Aboodi A. , Shuaib A. N. , Al-Nassar Y. , Al-Anizi S. S.
Published: September 2009

The tube-to-tubesheet joint strength is measured in terms of interfacial pressure between the tube’s outer surface and tubesheet bore. The strength of a rolled joint is influenced by several design parameters, including the type of tube and tubesheet materials, initial tube projection, and the initial radial clearance between the tube and tubesheet, among other factors. This paper uses finite element analysis (FEA) to evaluate the effect of several parameters on the strength of rolled joints having large overtolerances, a situation that applies to used equipment. An axisymmetric finite element model based on the sleeve diameter and rigid tube expanding roller concepts was used to analyze the effects of tube projection, initial tube-tubesheet clearance, and tube material strain-hardening property on the deformation behavior of the rolled tube and on the strength of the tube-tubesheet joint. The FEA results show that for zero tube projection (flush) the initial clearance effect is dependent on the strain-hardening capability of the tube material. For low strain-hardening tube material the interfacial pressure remains constant well above the Tubular Exchanger Manufacturer’s Association maximum overtolerance. A drastic reduction in joint strength is observed at high values of radial clearances. The cut-off clearance (clearance at which the interfacial pressure starts to drop) is found to vary linearly with the tube material hardening level, and the contact stress increases slightly for moderate strain-hardening tube materials but shows lower cut-off clearance levels. Furthermore, with flush tubes the maximum contact pressure occurs close to the secondary face (at the end of rolling) while for joints with initial tube projection the contact pressure shows two maxima occurring near the primary and the secondary faces. This is attributed to the presence of two elbows in tube deformation near the primary and secondary faces. The average interfacial pressure increased with increasing projection length for all clearances. Tube material strain hardening enhances the interfacial pressure in a similar fashion for all initial tube projection lengths considered in the analysis.
Estimation of Leak Flow Rates Through Narrow Cracks
Authors: Hong Chungpyo , Asako Yutaka , Lee Jae-Heon
Published: September 2009

The estimation of the gaseous leak flow rates through a narrow crack is important for a leak-before-break analysis as a method of nondestructive testing. Therefore, the methodology to estimate the gaseous leak flow rates in a narrow crack for a wide range of flow conditions, from no-slip to slip flow and from unchoked to choked flow, by using f⋅Re (the product of friction factor and Reynolds number) correlations obtained for a microchannel, was developed and presented. The correlations applied here were proposed by the previous study (Hong, et al., 2007, “Friction Factor Correlations for Gas Flow in Slip Flow Regime,” ASME J. Fluids Eng., 129, pp. 1268–1276). The detail of the calculation procedure was appropriately documented. The fourth-order Runge–Kutta method was employed to integrate the nonlinear ordinary differential equation for the pressure, and the regular-Falsi method was employed to find the inlet Mach number. An idealized crack, whose opening displacement ranges from 2 μm to 50 μm, with the crack aspect ratio of 200, 1000, and 2000, was chosen for sample estimation. The present results were compared with both numerical simulations and available experimental measurements. The results were in excellent agreement. Therefore, the gaseous leak flow rates can be correctly predicted by using the proposed methodology.
On the Material Modeling of the Autofrettaged Pressure Vessel Steels
Authors: Farrahi G. H. , Hosseinian E. , Assempour A.
Published: September 2009

Material modeling of high strength steels plays an important role in the accurate analysis of autofrettaged tubes. Although, the loading behavior of such materials is nearly elastic-perfectly plastic, their unloading behavior due to Bauschinger effect is very complicated. DIN1.6959 steel is frequently used for construction of autofrettaged tubes in some countries such as Germany and Switzerland. In spite of similarity between chemical compositions of this steel with that of A723 steel, due to different material processing, these two steels have an unlikely behavior. In this paper the material behavior of DIN1.6959 was accurately modeled by uniaxial tension-compression test results. Both 6 mm and 12.5 mm diameter specimens were used and compared. Also various relations for modeling of autofrettaged steels were investigated, and a new relation was introduced for accurate modeling. Moreover, two test methods, i.e., uniaxial tension-compression and torsion tests, used for modeling of autofrettage steels, were analyzed. Also, material models of three important autofrettage steels, i.e., A723, HB7, and DIN1.6959, were compared.
Modeling the Temperature Dependence of Tertiary Creep Damage of a Ni-Based Alloy
Authors: Stewart Calvin M. , Gordon Ali P.
Published: September 2009

To capture the mechanical response of Ni-based materials, creep deformation and rupture experiments are typically performed. Long term tests, mimicking service conditions at 10,000 h or more, are generally avoided due to expense. Phenomenological models such as the classical Kachanov–Rabotnov (Rabotnov, 1969, Creep Problems in Structural Members, North-Holland, Amsterdam; Kachanov, 1958, “Time to Rupture Process Under Creep Conditions,” Izv. Akad. Nauk SSSR, Otd. Tekh. Nauk, Mekh. Mashin., 8, pp. 26–31) model can accurately estimate tertiary creep damage over extended histories. Creep deformation and rupture experiments are conducted on IN617 a polycrystalline Ni-based alloy over a range of temperatures and applied stresses. The continuum damage model is extended to account for temperature dependence. This allows the modeling of creep deformation at temperatures between available creep rupture data and the design of full-scale parts containing temperature distributions. Implementation of the Hayhurst (1983, “On the Role of Continuum Damage on Structural Mechanics,” in Engineering Approaches to High Temperature Design, Pineridge, Swansea, pp. 85–176) (tri-axial) stress formulation introduces tensile/compressive asymmetry to the model. This allows compressive loading to be considered for compression loaded gas turbine components such as transition pieces. A new dominant deformation approach is provided to predict the dominant creep mode over time. This leads to development of a new methodology for determining the creep stage and strain of parametric stress and temperature simulations over time.
Fitness-for-Service Evaluation of Thermal Hot Spots and Corrosion Damage in Cylindrical Pressure Components
Authors: Tantichattanont P. , Adluri S. M. R. , Seshadri R.
Published: September 2009

Thermal hot spots and corrosion damage are typical of damages occurring in pressure vessels and piping. Structural integrity of such components needs to be evaluated periodically to determine “fitness-for-service” (FFS) of the components. In the present paper, three alternative methods for level 2 FFS assessments (as described in API 579) are proposed. They are based on variational principles in plasticity, the m-alpha method, the idea of reference volume, and the concept of decay lengths in shells. Decay lengths in the axial and circumferential directions for cylindrical shells are derived based on elastic shell theories. They are used to specify the reference volume participating in plastic action and the extent of what can be called “local” damage. Interaction between longitudinal and circumferential effects is investigated. A linear interaction curve is shown to give good estimation of the “remaining strength factor” for damage of practical aspect ratios. The stretching and bulging effects due to the damage are also studied. The limit defining the threshold to dominance of stretching action is proposed by using an approximate equilibrium calculation based on yield-line analysis. The effectiveness of the proposed assessments is demonstrated through an example and verified by level 3 inelastic finite element analysis.
Elastic Behavior of Cylindrical Vessels With Lateral Nozzle Under Internal Pressure
Authors: Gao P. , Li N. , Sang Z. F. , Widera G. E. O.
Published: September 2009

The objective of this work is to study the elastic stress distribution, deformation characteristic, and stress concentration factor (SCF) of a cylindrical vessel with lateral nozzle. Three full scale vessels under internal pressure with different geometric dimensions and lateral angle θ(θ=30 deg,45 deg,60 deg) are investigated by both experimental and three-dimensional finite element methods under internal pressure. A detailed stress distribution and the SCFs of the model vessels are provided. The results indicate that the maximum stress of cylindrical vessels with a lateral nozzle occurs at the acute side of the cylinder-lateral intersection and drifts off the longitudinal section of the cylinder for about 20 deg. When the geometric parameters of the vessels (d/D,D/T,t/T) are fixed, the SCF of the structure will increase with a decrease in the lateral angle θ.
Buckling of Imperfect, Axisymmetric, Homogeneous Shells of Variable Thickness: Perturbation Solution
Authors: Williams Dennis K. , Williams James R. , Hari Yogeshwar
Published: September 2009

This paper presents the first of a series of solutions to the buckling of imperfect cylindrical shells subjected to an axial compressive load. The initial problem is the case of a homogeneous cylindrical shell of variable thickness that is of an axisymmetric nature. The equilibrium equations as first introduced by Donnell over 70 years ago are thoroughly presented as basis for a solution employing perturbation methods. The ultimate objective of these calculations is to achieve a quantitative assessment of the critical buckling load considering the small axisymmetric deviations from the nominal shell wall thickness. Clearly in practice, large diameter thin wall shells of revolution that form stacks (as found in flue gas desulphurization absorber assemblies) are never fabricated with constant diameters and thicknesses over the entire length of the assembly. As such, ASME Boiler and Pressure Vessel Code Section VIII shell thickness tolerances as supplemented by ASME Code Case 2286-1 are reviewed and addressed in comparison to the resulting solutions with respect to the critical buckling loads. The method and results described herein are in stark contrast to the “knockdown factor” approach currently utilized in ASME Code Case 2286-1. Recommendations for further study of the imperfect cylindrical shell are also outlined in an effort to improve on the current rules regarding column buckling of large diameter shells designed in accordance with ASME Section VIII, Divisions 1 and 2 and ASME STS-1 in combination with the suggestions contained within Code Case 2286-1.
Plastic Instability Pressure of Toroidal Shells
Authors: Vu Vu Truong , Blachut J.
Published: September 2009

This paper considers the determination of plastic instability pressure in toroidal shells under internal uniform pressure. Analytical and numerical approaches, as well as verification by experiments, are presented. This work is inspired by Mellor’s treatment (1983, Engineering Plasticity, Ellis Horwood Ltd., Chichester; 1960, “The Ultimate Strength of Thin-Walled Shells and Circular Diaphragms Subjected to Hydrostatic Pressure,” Int. J. Mech. Sci., 1, pp. 216–228; 1962, “Tensile Instability in Thin-Walled Tubes,” J. Mech. Eng. Sci., 4(3), pp. 251–256), which assumed that plastic instability occurs at the maximum load. A closed-form formula of plastic instability condition is derived analytically. This expression for toroidal shells turns out to be the general case of spherical and cylindrical shells given by Mellor. Then the corresponding pressure is obtained by semi-analytical analysis for a material with the strain hardening characteristic, σ=A(B+ε)n. For the numerical approach, plastic instability pressure is the maximum pressure at which a small pressure increment causes a very large deformation. This is identified by the slope of pressure—change of volume curve approaching zero. Both approaches predict the onset of instability at the inner equator point. Experimental results of two nominally identical stainless steel toroidal shells correlated well to both approaches in terms of the magnitude of pressure and failure location.
Validation of a Feedback-Controlled Elbow Simulator Design: Elbow Muscle Moment Arm Measurement
Authors: Kuxhaus Laurel , Schimoler Patrick J. , Vipperman Jeffrey S. , Miller Mark Carl
Published: September 2009

The Allegheny General Hospital (AGH) elbow simulator was designed to be a closed-loop physiologic simulator actuating movement in cadaveric elbow specimens via servoelectric motors that attach to the tendons of the biceps, brachialis, triceps, and pronator teres muscles. A physiologic elbow simulator should recreate the appropriate moment arms throughout the elbow’s range of motion. To validate this design goal, muscle moment arms were measured in three cadaver elbow specimens using the simulator. Flexion-extension moment arms of four muscles were measured at three different pronation/supination angles: fully pronated, fully supinated, and neutral; pronation-supination moment arms were measured at three different flexion-extension angles: 30 deg, 60 deg, and 90 deg. The tendon-displacement method was used in these measurements, in which the ratio of the change in musculotendon length to the change in joint angle was computed. The numeric results compared well with those previously reported; the biceps and pronator teres flexion-extension moment arms varied with pronation-supination position, and vice versa. This is one of the few reports of both flexion-extension and pronation-supination moment arms in the same specimens, and represents the first use of closed-loop feedback control in the AGH elbow simulator. The simulator is now ready for use in clinical studies such as in analyses of radial head replacement and medial ulnar collateral ligament repair.
Computer Aided Biomodeling and Analysis of Patient Specific Porous Titanium Mandibular Implants
Authors: Parthasarathy Jayanthi , Starly Binil , Raman Shivakumar
Published: September 2009

Custom implants for the reconstruction of mandibular defects have recently gained importance due to their better performance over their generic counterparts. This is attributed to their precise adaptation to the region of implantation, reduced surgical times, and better cosmesis. Recent introduction of direct digital manufacturing technologies, which enable the fabrication of implants from patient specific data, has opened up a new horizon for the next generation of customized maxillofacial implants. In this article, we discuss a representative volume element based technique in which precisely defined porous implants with customized stiffness values are designed to match the stiffness and weight characteristics of surrounding healthy bone tissue. Dental abutment structures have been incorporated into the mandibular implant. Finite element analysis is used to assess the performance of the implant under masticatory loads. This design strategy lends itself very well to rapid manufacturing technologies based on metal sintering processes.
An Automated Drug Delivery Tracking Device Utilizing RFID Technology
Authors: Petro Julie A. , Pawluk Dianne T. V. , Burch David S. , Owen Justin M.
Published: September 2009

Medication errors are one of the most common types of medical errors involving a substantial number of individuals and accounting for a sizable increase in healthcare costs (Institute of Medicine, 2000, To Err Is Human: Building a Safer Health System, National Academies, Washington, DC). These errors are also potentially injurious or fatal (2008, “National Study on the Frequency, Types, Causes and Consequences of Voluntarily Reported Emergency Department Medication Errors,” J. Emerg. Med., in press). Currently, particularly in time critical tasks, such as during the treatment of a cardiac arrest, drugs may not be properly documented. This leads to an increased likelihood of subsequent medication errors with the patient. In order to efficiently and accurately record the time a drug is delivered, a device is needed that (1) records information with little or no intervention by the healthcare professional, so that they are free to focus on their primary task (of particular relevance in time critical tasks), (2) provides a precise time mark, and (3) is reliable for proper documentation. The prototype device proposed here for marking the time of drug delivery involves the use of radio frequency identification (RFID) technology. Each drug dose (i.e., the typically used preloaded syringes or packages) is labeled by a RFID tag mounted on it in terms of the type of drug and its dosage. Both the drug and the tag are enclosed in a radio frequency shielded sleeve to prevent the tag from being read prematurely by the time marking system. The time marking system itself consists of a RFID reader and a software or hardware based internal clock. When a drug is administered to a patient, the sleeve is opened, the drug is removed, and the RFID tag transmits encoded information to the reader, which then records the time of an internal clock. This setup results in the proposed time marking system providing a hands-free documentation of the time at which a specific drug is administered. The device requires little or no training on its use, is fast and efficient, can be easily integrated with current medical technology, and can be adapted to the various constraints of a healthcare setting. Requiring no time from healthcare professionals to mark the time of drug administration, the proposed time marking system will help alleviate error in documenting drug delivery.
Measurement of Soft Tissue Deformation to Improve the Accuracy of a Body-Mounted Motion Sensor
Authors: Liu Tao , Inoue Yoshio , Shibata Kyoko
Published: September 2009

Skin deformation caused by muscle motion is a common source of error for body-mounted sensors. A new method of measuring joint angles using a combination of two-axial accelerometers and reaction force sensors is presented. In this study, the effect of soft tissue deformation was minimized using a new reaction force sensor that is bound onto the body segment. The force sensor was designed using a pressure-sensitive electric conductive rubber. A Fourier transform of the total pressure forces induced by the body-mounted motion sensor modules was implemented to analyze the frequency property of soft tissue deformation on the human body surface. We processed the data of two-axial accelerations measured by the accelerometers using the measurements of soft tissue deformation including the total pressure force and two-directional coordinates of the center of pressure. An experimental study with ten subjects was implemented to verify the new sensor system proposed for estimating the joint angle of the knee. The effectiveness of this system is illustrated by the experimental results using an optical motion analysis system as a reference. If we use the accelerometers alone, the root mean square (RMS) difference and the coefficient of multiple correlation (CMC) over all the subjects walking at each of the three speeds (slow, average, and fast) are 6.3±1.4 deg and 0.93±0.05, 6.9±1.7 deg and 0.92±0.03, and 8.3±2.0 deg and 0.89±0.03, respectively. If we compensate for soft tissue deformation using the surface pressure measurements, the RMS difference and the CMC in each of the three conditions are 4.7±1.1 deg and 0.96±0.04, 5.0±1.5 deg and 0.96±0.04, and 6.6±1.9 deg and 0.93±0.03, respectively. Measurement results of the developed sensor system showed high correlation with results from two alternative methods including an optical motion analysis system and the goniometer system in walking analysis experiments. The results support the effectiveness of the proposed method in the measurement of the flexion and extension angle of the knee. The compensation for soft tissue deformation using the surface pressure measurements improved the accuracy of the body-mounted sensor in the experiments.
Agricultural Research, Productivity, and Food Prices in the Long Run
Authors: Alston Julian M. , Beddow Jason M. , Pardey Philip G.
Published: September 2009

A reinvestment in agricultural R&D is critical to ensuring sufficient food for the world in the coming decades.
Conserved Functions of Membrane Active GTPases in Coated Vesicle Formation
Authors: Pucadyil Thomas J. , Schmid Sandra L.
Published: September 2009

Coats, COPS, and GTPases

Within cells, vesicles coated with specific proteins, such as clathrin and adaptor complexes, concentrate and package cargo molecules to mediate transport between compartments.
Pucadyil and Schmid
(p.
1217
) review the role of membrane-active GTPases in coated vesicle formation and propose that, although structurally diverse, the Arf-family GTPases and dynamin may play mechanistically similar roles in quality control of cargo packaging and coated-vesicle maturation—and also as components of the machinery that mediates vesicle release into a cellular compartment.
Response to Comments on “Energy Uptake and Allocation During Ontogeny”
Authors: Zuo Wenyun , Moses Melanie E. , Hou Chen , Woodruff William H. , West Geoffrey B. , Brown James H.
Published: September 2009

Our extended ontogenetic growth model is a theoretical model based on conservation of energy and general biological mechanisms underlying ontogenetic growth. We do not believe that the comments of Makarieva
et al
. and Sousa
et al
. expose substantive problems with our model. Nevertheless, they raise interesting, still unresolved questions and point to philosophical differences about the role of theory and of simple, general models as opposed to complicated, specific models.
Recent Warming Reverses Long-Term Arctic Cooling
Authors: Kaufman Darrell S. , Schneider David P. , McKay Nicholas P. , Ammann Caspar M. , Bradley Raymond S. , Briffa Keith R. , Miller Gifford H. , Otto-Bliesner Bette L. , Overpeck Jonathan T. , Vinther Bo M. ,   Arctic Lakes 2k Project Members, Abbott M. , Axford Y. , Bird B. , Birks H. J. B. , Bjune A. E. , Briner J. , Cook T. , Chipman M. , Francus P. , Gajewski K. , Geirsdóttir Á. , Hu F. S. , Kutchko B. , Lamoureux S. , Loso M. , MacDonald G. , Peros M. , Porinchu D. , Schiff C. , Seppä H. , Thomas E.
Published: September 2009

Climate Reversal

The climate and environment of the Arctic have changed drastically over the short course of modern observation.

Kaufman
et al.

(p.
1236
) synthesized 2000 years of proxy data from lakes above 60° N latitude with complementary ice core and tree ring records, to create a paleoclimate reconstruction for the Arctic with a 10-year resolution. A gradual cooling trend at the start of the record had reversed by the beginning of the 20th century, when temperatures began to increase rapidly. The long-term cooling of the Arctic is consistent with a reduction in summer solar insolation caused by changes in Earth's orbit, while the rapid and large warming of the past century is consistent with the human-caused warming.
More Than Just Talking
Weather Matters
An American Cultural History Since 1900

by Bernard Mergen

University Press of Kansas, Lawrence, 2008. 408 pp. $34.95. ISBN 9780700616114.
Authors: Turner Roger
Published: September 2009

Mergen offers a wide-ranging consideration of Americans' experiences with and reactions to their weather
Rab35 Controls Actin Bundling by Recruiting Fascin as an Effector Protein
Authors: Zhang Jun , Fonovic Marko , Suyama Kaye , Bogyo Matthew , Scott Matthew P.
Published: September 2009

Fascin-Actin Rab Bristles

Rab proteins have diverse functions in directing intracellular traffic and may also affect development.

Zhang
et al.

(p.
1250
) show that during
Drosophila
development Rab35 influences the development of bristles, neurosensory structures built upon bundled actin. Rab35 also caused massive actin-rich filopodia protrusions from cultured cells. Activated Rab35 interacted directly with fascin, an actin filament bundling protein, to colocalize near the plasma membrane. When Rab35 was engineered to interact with the surface of mitochondria, it stimulated localized actin assembly in a fascin-dependent manner. Thus, fascin is a Rab35 effector protein that links membrane trafficking regulation to cytoskeleton assembly during development.
Fundamental Evolutionary Limits in Ecological Traits Drive
Drosophila
Species Distributions
Authors: Kellermann Vanessa , van Heerwaarden Belinda , Sgrò Carla M. , Hoffmann Ary A.
Published: September 2009

Adaptive Limits

Species adapt to a changing environment as a result of selection acting on current genetic variation. However, the degree of variation underlying traits that can respond to selection is unclear.

Kellermann
et al.

(p.
1244
; see the Perspective by
Merilä
) investigated the degree of genetic variation available to fruit flies for cold and desiccation tolerance. Species from the tropics tended to have low variability for these traits, while flies from more temperate climates showed higher levels of variation. However, overall genetic variability did not differ, suggesting that the tropical species lacked the alleles that confer tolerance to these environmental extremes and restrict their potential range.
Recruitment of Antigen-Specific CD8
+
T Cells in Response to Infection Is Markedly Efficient
Authors: van Heijst Jeroen W. J. , Gerlach Carmen , Swart Erwin , Sie Daoud , Nunes-Alves Cláudio , Kerkhoven Ron M. , Arens Ramon , Correia-Neves Margarida , Schepers Koen , Schumacher Ton N. M.
Published: September 2009

Preparation for Cell Wars

When T cells encounter an infection, they proliferate to create a larger army to fight the invader. The overall magnitude of the T cell response depends on the severity of infection and is determined by the number of T cells of a particular antigen specificity that are initially recruited, as well as the magnitude of the proliferative response. The extent to which these two components contribute to the response is unknown. By using DNA barcoding to track the responses of individual T cells,

van Heijst
et al.

(p.
1265
) showed that the recruitment of T cells of a particular antigen specificity is similar and nearly complete, but that the extent of the proliferative response differed, and this determined the overall magnitude of the T cell response.
An Ultramassive, Fast-Spinning White Dwarf in a Peculiar Binary System
Authors: Mereghetti S. , Tiengo A. , Esposito P. , La Palombara N. , Israel G. L. , Stella L.
Published: September 2009

X-ray observations show that a white dwarf has a mass near the limit above which these stars become gravitationally unstable.
A Sulfilimine Bond Identified in Collagen IV
Authors: Vanacore Roberto , Ham Amy-Joan L. , Voehler Markus , Sanders Charles R. , Conrads Thomas P. , Veenstra Timothy D. , Sharpless K. Barry , Dawson Philip E. , Hudson Billy G.
Published: September 2009

Toughing It Out in Membranes

The formation of crosslinks in the triple-helical structure of collagen is crucial to its function. In the case of collagen IV, which provides structural integrity to the basement membrane of animal tissues, the chemical nature of the crosslinks has been difficult to pin down.

Vanacore
et al.

(p.
1230
) report a combination of high-resolution mass spectrometric and nuclear magnetic resonance studies that establish the crosslink between hydroxylysine-211 and methionine-93 is a sulfimine group (-S=N-). This type of bond appears to have evolved to withstand mechanical stress as animals evolved into more structurally complex organisms.
Differential Sensitivity to Human Communication in Dogs, Wolves, and Human Infants
Authors: Topál József , Gergely György , Erdőhegyi Ágnes , Csibra Gergely , Miklósi Ádám
Published: September 2009

Boxing Clever?

Piaget showed that 10-month-old infants will persist in looking for a toy in box A, where it has been placed several times, even after having been shown that it has been moved to box B, whereas 12-month-old infants do not. This phenomenon marks a developmental milestone in human infant cognition that

Topál
et al.

(p.
1269
; see the Perspective by

Tomasello and Kaminski

and the news story by

Pennisi

) explored in a remarkable series of comparative tests. The results support the view that infants and adult dogs will both persevere in searching erroneously in box A because they regard the placement of the toy by a human experimenter as a social teaching event. By contrast, wolves rapidly learn correctly to search box B. They also observed that infants are able to generalize and thus still persevere when one experimenter places the toy in box A and a second then places the toy in box B. Dogs, however, display episodic learning, and a second experimenter reduces their searching choice to chance.
Evolutionary Biology for Doctors
Principles of Evolutionary Medicine

by Peter Gluckman, Alan Beedle, and Mark Hanson

Oxford University Press, Oxford, 2009. 312 pp. $130, £65. ISBN 9780199236381. Paper, $65, £32.50. ISBN 9780199236398. www.evomedicine.org
Authors: Ellison Peter T.
Published: September 2009

Gluckman, Beedle, and Hanson provide medical students and physicians with an introduction to evolutionary biology focused on topics important to human and public health.
Smoothened
Mutation Confers Resistance to a Hedgehog Pathway Inhibitor in Medulloblastoma
Authors: Yauch Robert L. , Dijkgraaf Gerrit J. P. , Alicke Bruno , Januario Thomas , Ahn Christina P. , Holcomb Thomas , Pujara Kanan , Stinson Jeremy , Callahan Christopher A. , Tang Tracy , Bazan J. Fernando , Kan Zhengyan , Seshagiri Somasekar , Hann Christine L. , Gould Stephen E. , Low Jennifer A. , Rudin Charles M. , de Sauvage Frederic J.
Published: September 2009

A Smooth(ened) Path to Drug Resistance

The Hedgehog (Hh) signaling pathway has emerged as a key contributor to the growth of medulloblastoma, an aggressive brain tumor. GDC-0449, a drug that ramps down this signaling pathway by binding to the Hh pathway component Smoothened, was recently shown to induce rapid and dramatic tumor regression in a patient with metastatic medulloblastoma, but the tumor eventually developed resistance to the drug.

Yauch
et al.

(p.
572
, published online 3 September) show that resistance arose because the tumor acquired a mutation in Smoothened that disrupts binding of the drug. Identification of this resistance mechanism may facilitate the design of next-generation drugs for this type of cancer.
Erasing Fear Memories
Authors: Pizzorusso Tommaso
Published: September 2009

Why are memories of traumatic events nearly impossible to eliminate?
Disrupting Hedgehog May Reverse Advanced Cancer, If Only Temporarily
Authors: Kean Sam
Published: September 2009

A drug has dramatically shrunk cancerous tumors by disrupting a key genetic pathway, although one deadly brain cancer quickly developed resistance. A
study
published online this week in
Science
describes the mechanism by which this resistance developed.
Ancient DNA Says Europe's First Farmers Came From Afar
Authors: Balter Michael
Published: September 2009

In a
paper
published online this week in
Science
, European researchers for the first time directly compare ancient DNA from European hunter-gatherers and early farmers. They conclude that outside colonizers brought farming to central Europe in a major migration event about 7500 years ago.
Dismissal of Senior Scientist for ‘Nonattendance’ Shakes Community
Authors: Gunson Phil
Published: September 2009

The dismissal of a top Venezuelan scientist from a government research institute and threats to dismantle one of its most successful programs have revived accusations that the government of President Hugo Chávez is engaging in political persecution.
Science Needs Kids With Vision
Authors: Holden Constance
Published: September 2009

Many of those with exceptional spatial abilities are being missed in most science talent searches, claimed a psychologist at a workshop last week on innovation by the National Science Foundation's National Science Board.
Dam Project Reveals Secret Sanctuary of Vanishing Deer
Authors: Stone Richard
Published: September 2009

In just 4 months, a research team in northern Laos captured an astounding 38 large-antlered muntjacs—a rare deer that was discovered only in 1994 and was photographed for the first time by a camera trap in 2007.
How Will Science Fare?
Authors: Normile Dennis
Published: September 2009

This year, the newly elected Democratic Party has responsibility for finalizing the budget of the Japanese education ministry—and no one knows how R&D will fare.
The Case of the Midwife Toad: Fraud or Epigenetics?
Authors: Pennisi Elizabeth
Published: September 2009

A new analysis published this week suggests that Paul Kammerer's long-discredited experiments may have been the first demonstrations of a recently recognized phenomenon: epigenetics.
Potent HIV Antibodies Spark Vaccine Hopes
Authors: Cohen Jon
Published: September 2009

A large team of researchers
reports
online in
Science
this week that it has identified the most powerful, broad-acting antibodies yet against multiple strains of HIV.
Sugary Achilles' Heel Raises Hope For Broad-Acting Antiviral Drugs
Authors: Service Robert F.
Published: September 2009

At the fall meeting of the American Chemical Society, researchers reported that a protein that binds sugar groups on the outermost proteins of HIV, gumming up the virus's machinery for entering cells, does nearly as well against the SARS and Ebola viruses, showing promise as a broad-spectrum antiviral.
New Trick for Splitting Water With Sunlight
Authors: Service Robert F.
Published: September 2009

At the American Chemical Society fall meeting, a team reported incorporating a mimic of the natural catalyst of photosynthesis into a solar cell to create what amounts to artificial photosynthesis: a device that turns sunlight into fuel.
Altered Microbes Make Dark-Horse Biofuels
Authors: Service Robert F.
Published: September 2009

At the American Chemical Society fall meeting, bioengineers reported equipping photosynthetic algae with the metabolic machinery needed to make isobutanol, a potential alcohol biofuel, and tweaking a reluctant microbe to make large quantities of
n
-butanol, another commercially important chemical.
Borrelia burgdorferi
Sensu Lato Species in Europe Induce Diverse Immune Responses against C
6
Peptides in Infected Mice
Authors: Krupka Inke , Knauer Jens , Lorentzen Leif , O'Connor Thomas P. , Saucier Jill , Straubinger Reinhard K.
Published: September 2009

The diversity of Lyme-borreliosis-inducing
Borrelia
species in Europe set high standards for the use of serodiagnostic test systems in terms of specificity and sensitivity. In the United States, the one-step C
6
antibody test system based on the invariable domain IR6 of the VlsE molecule has been established as a successful diagnostic tool for testing canine samples. However, only a limited set of data are available regarding the antigenicity of the C
6
peptides in an experimental murine model and sensitivity of the test regarding European
Borrelia
species. In order to investigate antibody reactions induced by these spirochetes, a total of 142 C3H/HeN mice were inoculated with
Borrelia burgdorferi
sensu stricto N40,
B. garinii
PBi, two isolates of
B. afzelii
,
B. spielmanii
A14S,
B. valaisiana
Rio6,
B. valaisiana
VS116, or
B. lusitaniae
. Infection of the mice was documented utilizing tissue culture and PCR. The IR6 sequences of
B. burgdorferi
sensu stricto B31,
B. garinii
IP90, and two
B. afzelii
ACAI strains have been used to synthesize and test additional C
6
peptides. Compared to the well-established two-tiered test system, the results indicate that single C
6
peptides derived from
B. burgdorferi
sensu stricto and
B. garinii
can be used in an enzyme-linked immunosorbent assay-based technique to detect murine antibodies induced by either agent. Little is known about the prevalence or pathogenicity of the
B. afzelii
strains in mammalian hosts, but our experimental data indicate differences in the C
6
peptide test sensitivity for the detection of antibodies induced by different strains or isolates of
B. afzelii
.
Simple and Rapid Lateral-Flow Assay for the Detection of Foot-and-Mouth Disease Virus
Authors: Oem Jae Ku , Ferris Nigel P. , Lee Kwang-Nyeong , Joo Yi-Seok , Hyun Bang-Hun , Park Jong-Hyeon
Published: September 2009

A simple lateral-flow assay (LFA) based on a monoclonal antibody (MAb 70-17) was developed for the detection of foot-and-mouth disease virus (FMDV) under nonlaboratory conditions. The LFA was evaluated with epithelial suspensions (
n
= 704) prepared from current and historical field samples which had been submitted to the Pirbright Laboratory (United Kingdom) and from negative samples (
n
= 100) collected from naïve animals in Korea. Four FMDV serotypes (type O, A, Asia 1, and C) were detected in the LFA, but not the remaining three FMDV serotypes (SAT 1, SAT 2, and SAT 3). The diagnostic sensitivity of the LFA for FMDV types O, A, C, and Asia 1 was similar, at approximately 87.3%, to that of 87.7% obtained with antigen enzyme-linked immunosorbent assay (Ag-ELISA). The diagnostic specificity of the LFA was 98.8%, compared to 100% for the Ag-ELISA. These results demonstrate that the LFA using the FMDV MAb 70-17 to detect FMDV is a supportive method for taking rapid measurements at the site of a suspected foot-and-mouth disease outbreak in Asia before diagnosing the disease in the laboratory, thereby offering the possibility of implementing control procedures more rapidly.
Perinatal Tuberculosis in a 73-Day-Old Infant
Authors: Huang Hsin-Chung , Huang Li-Min , Lu Chun-Yi , Lee Ping-Ing , Chang Luan-Yin
Published: September 2009

A 73-day-old female infant presented with cough and fever. A chest roentgenogram showed a pneumonic patch, but empirical antibiotic treatment failed. The pathology of an excisional biopsy specimen confirmed pulmonary tuberculosis. We emphasize that tuberculosis should be considered for neonates or infants with unresponsive pneumonia because delayed diagnosis is associated with a fatal outcome.
Refractory Bacteremia and Osteomyelitis Resulting in Fatal Bacteremic Pneumonia with Multiorgan Failure Caused by
Mycobacterium simiae
in a Non-Human Immunodeficiency Virus-Infected Adult
Authors: Chung Kuei-Pin , Tsai Tzu-Hsiu , Huang Yu-Tsung , Hsueh Po-Ren
Published: September 2009

Bacteremic pneumonia caused by
Mycobacterium simiae
in non-human immunodeficiency virus (HIV)-infected patients has rarely been reported. We describe a non-HIV-infected adult with refractory bacteremia, osteomyelitis, and colonization of
M. simiae
in the respiratory tract who subsequently developed fatal bacteremic pneumonia. The isolate was confirmed as
M. simiae
by 16S rRNA gene analysis.
Multisite Comparison of Anti-Human Immunodeficiency Virus Microbicide Activity in Explant Assays Using a Novel Endpoint Analysis
Authors: Richardson-Harman Nicola , Lackman-Smith Carol , Fletcher Patricia S. , Anton Peter A. , Bremer James W. , Dezzutti Charlene S. , Elliott Julie , Grivel Jean-Charles , Guenthner Patricia , Gupta Phalguni , Jones Maureen , Lurain Nell S. , Margolis Leonid B. , Mohan Swarna , Ratner Deena , Reichelderfer Patricia , Roberts Paula , Shattock Robin J. , Cummins James E.
Published: September 2009

Microbicide candidates with promising in vitro activity are often advanced for evaluations using human primary tissue explants relevant to the in vivo mucosal transmission of human immunodeficiency virus type 1 (HIV-1), such as tonsil, cervical, or rectal tissue. To compare virus growth or the anti-HIV-1 efficacies of candidate microbicides in tissue explants, a novel soft-endpoint method was evaluated to provide a single, objective measurement of virus growth. The applicability of the soft endpoint is shown across several different ex vivo tissue types, with the method performed in different laboratories, and for a candidate microbicide (PRO 2000). The soft-endpoint method was compared to several other endpoint methods, including (i) the growth of virus on specific days after infection, (ii) the area under the virus growth curve, and (iii) the slope of the virus growth curve. Virus growth at the assay soft endpoint was compared between laboratories, methods, and experimental conditions, using nonparametric statistical analyses. Intra-assay variability determinations using the coefficient of variation demonstrated higher variability for virus growth in rectal explants. Significant virus inhibition by PRO 2000 and significant differences in the growth of certain primary HIV-1 isolates were observed by the majority of laboratories. These studies indicate that different laboratories can provide consistent measurements of anti-HIV-1 microbicide efficacy when (i) the soft endpoint or another standardized endpoint is used, (ii) drugs and/or virus reagents are centrally sourced, and (iii) the same explant tissue type and method are used. Application of the soft-endpoint method reduces the inherent variability in comparisons of preclinical assays used for microbicide development.