bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromotive Force Stability of Nicrosil-Nisil®
Authors: Wang TP , Starr CD
Published: February 2009

Early data on the aging characteristics of experimental heats of Nicrosil (Ni-14.2Cr-1.4Si-0.1Mg) and Nisil® (Ni-4.2Si-0.1Mg) versus Type K thermoelements are reviewed. The electromotive force stability of Nicrosil-Nisil in 1.6-mm (0.064-in.), 0.8-mm (0.032-in.), and 0.3-mm (0.0126-in.) diameter wire at 500°C in air up to 200 h is obtained in situ and is compared with that of Type K thermoelements of the same size. The mechanism of EMF changes is discussed.
Generalized Application of Neuber's Rule
Authors: Seeger T , Heuler P
Published: February 2009

An analysis is presented concerning problems of correct application of approximation formulas such as Neuber's rule for the case of inelastic net section behavior of notched members. The rules developed allow a generalized consideration of elastic-plastic net section behavior for any type of loading and notch geometry. The analysis is illustrated by discussion of experimental and calculated load-notch strain curves of different specimens.
An Acceptance Plan for Feather and Down Products
Authors: Landes W
Published: February 2009

A method of deciding whether an article filled with a feather and down mixture is properly labeled was published in 1971. It required the calculation of three factors: the mean, the standard deviation, and the t statistic. The present paper presents tables of acceptance values for various combinations of producer risk and consumer risk, eliminating the need for the calculation of the t statistic. The previous paper required a minimum sample of four specimens, while the present paper provides an opportunity for reduced sampling and testing by presenting acceptance values for n = 2 and n = 3, which can be used in routine quality control work. Finally, operating characteristic curves, showing how the probability of acceptance varies with the percentage of down in the finished product, are given for several different plans.
Creep Rupture Testing of Aluminum Alloys: Metallographic Studies of Fractured Test Specimens
Authors: Agrawal SP , Byrnes LE , Yaker JA , Leslie WC
Published: February 2009

Specimens of 1100, 5454, and 6061 aluminum alloys were examined after failure in creep rupture tests of up to 20 000 h duration. No microstructural changes occurred in 1100-O and 5454-O alloys during testing other than slight grain growth at the highest test temperatures. Such growth had only a small effect on creep-rupture properties. Cold-worked alloys 1100-H14 and 5454-H34 were unstable during creep, passing through stages of recovery, recrystallization, and grain growth. These changes invalidate extrapolation of short-time data. The precipitation-hardened 6061 alloy underwent drastic changes in microstructure during testing, from thin needle-shaped precipitates to larger β′ rods to coarse β-Mg2Si plates. These changes produced several different slopes in the log stress-log rupture time plots and long-time rupture stresses considerably below those predicted by extrapolation.
Estimating Plane Strain Fracture Toughness of High Strength Aluminum Alloys from Crack Arrest Toughness
Authors: Dorward RC , Hasse KR
Published: February 2009

A comparison is made between fracture toughness KIc as measured by recommended ASTM procedures and crack arrest toughness KIa as measured on more than 100 bolt-loaded double-cantilever beam (DCB) specimens from 7075, 7050, and 7049 alloy plates. Close agreement was found between the two values, KIa being on the average about 0.75 ksiin. (0.82 MPa√m) lower than than KIc over the range 18 to 29 ksiin. (20 to 32 MPa√m). This indicates that a simplified test based on a bolt-loaded DCB specimen could be used for quality control, lot release, and screening purposes. Measurements of crack length and specimen deflection are all that are required; the specimens do not have to be fatigue precracked, nor is a tensile machine needed.
Problems in Standardization of Implantable Stimulation Electrodes
Authors: Maurer DD
Published: February 2009

The emphasis for standardization of implantable stimulating electrodes should be on performance. Among the functional characteristics of the stimulating electrode, only the physical properties may be amenable to some immediate performance standardization. Electrical properties of the stimulating electrode relating to safety may be defined in terms of performance standards in the near future, while those relating to efficacy may evolve later. Standardization of impedance or other electrical design characteristics should not be considered apart from their direct, verified relationship to safety and efficacy of the implant.
Static and Impact Properties of Laminated Hybrid Composites
Authors: Mallick PK , Broutman LJ
Published: February 2009

The static and impact properties of hybrid composite systems containing various high performance fibers in an epoxy matrix have been studied as a function of lamination configuration. From instrumented impact test data, fracture initiation and propagation energies were calculated and reported in terms of a measurement called “ductility index.” It was shown that with a proper choice of lamination configuration, a large increase in impact energy as well as ductility index can be achieved in hybrid systems. Among other factors, the impact properties also depend on the type of fiber and interlaminar shear strength.
Shear Strength of Sand at Constant Volume
Authors: Sadasivan SK , Raju VS
Published: February 2009

To verify the expressions developed by other researchers for separating the strength component resulting from volume change in shear (dilatancy), shear tests at constant volume as well as drained tests are necessary. In conventional undrained triaxial tests on granular materials, volume change of the soil skeleton occurs as a result of rubber membrane penetration. In the present investigation, conventional tests were modified to ensure a constant volume condition by compensating for the rubber membrane penetration.

Drained tests, conventional undrained tests, and modified undrained tests were conducted on a uniform medium sand, uniform coarse sand, and a gap-graded sand; the results are compared. Conventional undrained tests gave somewhat higher values of shear strength than those of modified undrained tests. The results of drained tests corrected for volume change compare well with those of modified undrained tests.
Scale and Corrosion Parameters at a Geothermal Loop Experimental Facility
Authors: Jacobson WO , Rogers AN , Schoepflin F , Henry PM
Published: February 2009

Metallic alloys and nonmetallic materials, including coatings and plastic liners, were exposed to high-temperature (232.2°C [450°F]), highly saline (20%) brines in a 10-MW geothermal loop experimental facility at the Salton Sea Known Geothermal Resource Area in the Imperial Valley, Calif. Mild carbon steel corrodes rapidly, especially in presence of air, while nickel alloys are very resistant to the Salton Sea geothermal brines. The Teflon® coatings and the vinyl esters exhibited the greatest resistance among the nonmetallic materials tested. Twenty-seven proprietary scale inhibitors were tested to determine the ones most promising for use in the Salton Sea brines. Several scale control additives were effective in retarding silica precipitation at 90°C, the temperature limit of these laboratory tests.
Comparison of Methods for Fracture Toughness Determination in Steels
Authors: Cobanoglu MM , Kardos G
Published: February 2009

This study compares various test methods and estimation procedures that are available for determining the fracture toughness of steels. The ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399), the energy rate test, and the multiple identical specimen crack growth resistance R curve test for elastic-plastic fracture toughness JIc determination are compared. Various formulations for plane-strain fracture toughness KIc and JIc estimation are also compared. Comparison of the test methods indicates that, for ductile steels, the multiple identical specimen R curve test is the most promising. It is suggested that the total areas be used for calculation of J from Rice's approximate formulation for three-point bend specimens of ductile steels and crack-contributed areas for brittle steel three-point bend specimens.
On the Relationship of Toughness, Fracture Initiation Energy, and Specimen Deflection in Charpy Tests of 4340 Steel
Authors: Datta KP , Wood WE
Published: February 2009

The toughness of quenched 4340 steel (American Iron and Steel Institute designation) has been studied as a function of notch root radius and tempering temperature for several testing conditions (such as room temperature slow-bend Charpy, room temperature instrumented Charpy). The toughness, the square root of the fracture initiation energy, and the specimen deflection at fracture initiation follow similar trends under identical conditions in each type of testing. Thus fracture initiation energy and the specimen deflection in Charpy testing can be measures of toughness. These three macroscopic relationships are independent of fracture morphology, grain size, or plastic zone size. Theoretical relationships among the three are proposed.
Simplified Equations for Peak Position and for Its Standard Deviation in X-Ray Stress Measurement
Authors: Kurita M
Published: February 2009

Simplified equations for peak position and for its standard deviation resulting from counting statistics are derived in the n points parabola method. These equations are applicable to an even as well as an odd n and can be rapidly calculated even with an inexpensive on-line computer such as a microcomputer. Thus a rapid and precise peak determination can be made by use of these equations with an inexpensive X-ray stress measurement system. Various peak positions calculated by the n points and the three points parabola methods were compared. Two heat-treated steels were used. The n points method, using all the data points that fall above approximately 85% of the maximum intensity, gave the most satisfactory result. On the other hand, the three points method produced a large standard deviation of the peak position unless the three points were taken symmetrically about the diffraction peak.
Some Aspects of Biaxial Creep Testing of Thin-Walled Cylindrical and Spherical Pressure Vessels
Authors: Arbel A , Eliezer D
Published: February 2009

Expressions are derived for the expansion of cylindrical and spherical pressure vessels that creep at a constant temperature while being internally pressurized by a constant amount of an ideally behaving gas. The main portion of the initial volume of the pressure vessels is occupied by a rod or a ball-type insert to reduce the energy released or containment requirement if a rupture should occur.
Task Group Report: Results of Interlaboratory Test Programs to Evaluate the Dynamic Tear Test Method
Authors: Lazaridis NA , Heberling TG , Harris ES , Lange EA
Published: February 2009

An ASTM Task Group evaluated the revised Standard Test Method for Dynamic Tear Energy of Metallic Materials (E 604). The revised method expanded the range of specimen thickness from the 16 mm (⅝ in.) specified in E 604-77 to include specimens ranging from 4.8 to 16 mm (3/16 to ⅝ in.) in thickness. The minimum impact velocity was also changed from 4.9 to 4 m/s (16 to 13 ft/s). Three series of tests were conducted by 16 laboratories on steels of low, intermediate, and high yield strength. A total of 1300 specimens were involved over a two-year period, and the results were analyzed statistically to support the modifications in the dynamic tear test method. No variations of engineering significance in dynamic tear energy were found with respect to between-laboratory variation in procedures, testing machine type, impact velocity, and specimen preparation within the tolerances set for the dimensions of the test specimens and the critical parameters of the testing procedure.
A Torsion Pendulum for Measurement of Damping Capacity and Related Phenomena
Authors: James DW , Stott JD , Emery B
Published: February 2009

Investigation of the damping mechanisms of metals and alloys requires that damping capacity measurements be made over wide stress, frequency, and temperature ranges. The torsion pendulum described herein fulfills these requirements in all respects except that it has a limited (low) frequency range. This versatile apparatus also allows creep, fatigue, stress relaxation, elastic after-effect, static and dynamic moduli and hysteresis curves to be made at temperature and in vacuo. It is possible to superimpose a magnetic field on the specimen during these measurements. The specimen may also be heat treated or plastically deformed in situ. An electronic data processing system has been designed to calculate and plot material damping characteristics during a free decay test. The damping characteristics are thus obtained more quickly and with greater accuracy than was previously possible.
A Concept for Fatigue Analysis of Complex Components
Authors: Leis BN
Published: February 2009

Recently, a two-step procedure that determines local stresses and strains as functions of loading and that assesses the fatigue damage they cause in terms of smooth specimen laboratory test data has shown promise in making consistently accurate life to crack initiation predictions of notched specimens. However, this procedure, which accounts for notch effects by using a single parameter, is less accurate in predicting the fatigue life for complex components than that for simple notched specimens. The present paper examines the problems of predicting the fatigue life of complex components and structures. It is shown that fatigue life in such structures is governed by the multiplicity of initiation locations and crack initiation mechanisms. An approach is outlined whereby the role of each potential initiation location and mechanism is accounted for in fatigue analysis of the structures by using the two-step procedure. Fatigue life predictions are made for a hypothetical complex component to illustrate the approach and its application. The accuracy of the approach is then assessed by comparing the results of actual test data for a built-up box beam with those simulated by using the approach outlined in this paper.
Structural Materials for Nuclear Power Plants
Authors: Bush SH
Published: February 2009

Commercial ferritic and austenitic steels are the predominant materials used in both fossil and nuclear power plants; the significant difference in nuclear plants is the exposure to neutron fluence. Three aspects of material behavior are reviewed: (1) the role of residual elements on radiation damage of steels used for water reactor pressure vessels, (2) influence of neutron-gamma flux and water reactor coolant on stress corrosion, and (3) neutron-induced swelling and void formation in austenitic stainless steels in fast reactors.
Laser-Heating-Induced Failure of Metal Alloys Under Constant Stress
Authors: McLellan DL
Published: February 2009

The failure conditions of three structural materials have been investigated under a number of constant axial tensile stresses and rapid heating rates. Laser heating was used to produce failure by fracture for selected times between nominally 0.10 and 100 s. The three sheet gage materials tested were 2024-T81 (alclad), Ti-6Al-4V (mill annealed), and 301 stainless steel (hard). Properties determined in this manner are applicable to vulnerability analyses of aircraft and missile structures. Temperatures for 1-s failure times of constantly stressed parts are significantly higher than those which accompany both the static ultimate tensile strength and long-duration creep rupture behaviors.
Magnetomechanical Damping Properties of AISI 403 Stainless Steel with Applied Static Torsional and Axial Stresses
Authors: Willertz LE
Published: February 2009

The magnetomechanical damping properties of an AISI 403 stainless steel, tested in torsion, were found to behave differently under the action of applied static axial and torsional stresses. A constant torsional stress decreased the damping peak, broadened it, and shifted it to higher stresses. In contrast, a static axial load shifted the peak to lower log decrement values but did not change the peak damping stress. These observations are explained in terms of the effect of the static stresses on the shape of the stress-strain hysteresis loop.
Comparison of Static and Dynamic Mechanical Properties of Some Epoxy-Matrix Composites
Authors: Jenness JR , Kline DE
Published: February 2009

Static and dynamic elastic moduli in flexure were measured for a diglycidyl ether of bisphenol A cured with metaphenylenediamine and some particulate composites with this polymer as the matrix. If it is assumed that these materials have tensile moduli which are about 0.925 of their compressive moduli, as has been noted for another epoxy system, dynamic moduli determined at very low strain values by a free-free flexural resonance technique appear to be very nearly equal to the tensile moduli in static flexure. However, little correlation was observed between the dynamic mechanical properties and other static properties such as flexural strength. This is partially attributed to the difference in stress patterns in the static and dynamic tests.
Procedures Used to Evaluate the Thermal Properties of Soils Adjacent to Buried Extra High Voltage Lines
Authors: Salomone LA , Fischer JA , Watson I
Published: February 2009

Because of the high voltages and operating temperatures now being considered for transmission lines from offshore generating stations, assessment of the thermal characteristics of the soils surrounding these cables is critical—both to avoid failure of the cables by overheating and to establish a practical engineering procedure to facilitate sound and economic cable designs in the future.

A tridirectional approach used in a case history study to establish values of thermal resistivity along proposed offshore and onshore cable alignments is described. The procedural format developed is considered to have useful general application to this type of problem. Soils studied included clean sands and silty sands, silts, clays, and organic material (peat).
The Application of the Single-Edge Notched Beam to Fracture Toughness Testing of Ceramics
Authors: Simpson LA , Hsu TR , Merrett G
Published: February 2009

There is a need for easy-to-fabricate fracture toughness specimens for ceramics. The single-edge notched beam satisfies this need, except that the American Society for Testing and Materials (ASTM) specification for notch root crack depth is difficult to achieve in ceramics using standard metallurgical methods. Finite element techniques are used to demonstrate that a minimum ratio of crack depth to notch root radius of 0.5 is sufficient for a valid test in a ceramic. These calculations are confirmed by experiments on soda-lime glass specimens.
A New Test for Sulfate Resistance of Cements
Authors: Mehta PK , Gjørv OE
Published: February 2009

Sulfate attack on concrete can either be of expansion-cracking type due to ettringite formation or of surface deterioration type due to acidic nature of sulfate solutions. The present test methods for determining sulfate resistance generally evaluate the expansive attack phenomenon. Since low C3A portland cements are not susceptible to this type of attack, new methods need to be developed to test the long-time resistance of these cements to the acidic type of sulfate attack. An attempt to develop a laboratory method involving immersion of small specimens of cement paste in a sulfate solution held at constant pH is described. Preliminary results are given for five different types of cements tested in accordance with the new method.
An Investigation of the Fluid Characteristics of Cement Grouts
Authors: Huang WH
Published: February 2009

A method for viscosity measurement of cement grouts is discussed in this paper and the results are presented in the form of formulas and curves.

The cement used in the tests was Type II portland cement. It was found that the cement grouts with water/cement ratios of 0.42 to 0.44 have fluid characteristics of Bingham plastic type.

The hydraulic grade line of grout in a tendon duct was estimated using laboratory viscosity data and was compared with a field test.
Computational Aids for Kinematic Viscosity Conversions from 100 to 210°F to 40 and 100°C
Authors: Manning RE
Published: February 2009

In the petroleum industry the standard temperatures of test are being changed from the traditional 100 and 210°F to 40 and 100°C. Graphs and tables are given which allow for easy, accurate calculation of kinematic viscosity at the new test temperatures from data at the former test temperatures.
The Calculation of Gas Transmission Rates Measured by Manometric Methods
Authors: Evans RE
Published: February 2009

It is shown that an error in the calculated gas transmission rate of greater than 20 percent can result when using the standard equation presented in Method M of the American Society for Testing and Materials Test for Gas Transmission Rate of Plastic Film and Sheeting [D 1434–66 (1972)]. The magnitude of this error is shown to be a function of both cell void volume and pressure. Therefore, disagreements in results calculated using different cells and operating conditions can be explained. The exact solution of the equation is presented together with an approximation; the latter facilitates calculations and results in an error of less than one percent.
Evaluation of Large Strains in Industrial Applications
Authors: Wolak J , Parks VJ
Published: February 2009

For the case of a two-dimensional strain field the usual concepts of direct and of shear strains are developed in terms of the principal strains and of the orientations of the elements in question. These expressions are used to form a Mohr's circle, which permits the transformation of strain from one axis of reference to another, irrespective of the magnitude of the strain, and leads to the evaluation of the principal strain components from the measurement of direct strain in three directions. A numerical example of application to the mechanics of metal cutting is given.

The paper may be of interest to metal-forming engineers and to specialists working in areas involving the analysis of large plastic strains.
Distinction Between Coaxial and Noncoaxial Strains in Sheet Metal and Its Implications on the Assessment of Material Formability
Authors: Hsü TC
Published: February 2009

The distinction between coaxial and noncoaxial strains is explained. It is shown that with noncoaxial strains deformation does not necessarily produce a change of shape, if circles and ellipses are used for strain measurements. If materials are tested in exisymmetrical processes, in which the strains are coaxial, and used in unsymmetrical ones, in which the strains are noncoaxial, then the formability will appear to be overestimated. A test for coaxiality, based on the use of squares and parallelograms for the strain measurements, is presented in the text and the formula used is derived in the Appendix.
Characterization of Galvanized Sheet Steel for Automotive Vehicle Bodies
Authors: Pearlstein F , Gallaccio A
Published: February 2009

Commercially available galvanised steel sheet materials, obtained from several sources and representing sinc coatings of conventional spangles (sinc crystal faces), minimized spangles, and diffusion alloy (galvanneal), were characterized for quality and performance. Thicknesses of the galvanised coatings were determined by chemical stripping (procedures for which are offered), by microscopic examination of cross-sectioned specimen, and by magnetic and eddy-current measuring devices. These methods were compared for reproducibility and suitability for general use. Corrosion resistances of the galvanised steels were determined following specific periods of exposure of specimens in 5% salt-fog environment.

Bare galvanized steel sheets having a minimum coating thickness of 14 µm and averaging about 22 µm completely resisted rusting for 72 h in salt-fog. Since longer exposure (96 h) in some cases resulted in rusting of the steel substrate, the 72-h exposure period was recommended for quality control purposes. The adhesive and protective value of a conventional paint system applied to the galvanized materials are discussed. Bead and spot weldings of the galvanized sheets were performed successfully; typical and feasible welding procedures are described. The amenability of the various galvanized materials to forming or shaping without flaking of or damage to the coatings was demonstrated.

Conclusions regarding the suitability of the test methods and their adoption are offered. Recommendations for use of the materials, application of preferred thickness measuring methods, and acceptance of corrosion resistance qualifying criteria are presented.
A Comparison of the Elevated Temperature Strength Loss in High Tensile Strength Graphite/Epoxy Composite Laminates Due to Ambient and Accelerated Aging
Authors: Hofer KE , Stander M , Rao PN
Published: February 2009

A comparison is made between ambient and accelerated aged panels and panels tested immediately after curing. Strength reductions as a function of time of aging and temperature for several orientations of laminates were determined. The effect of adding interlayers of glass scrim cloth between graphite plies was investigated. The high tensile strength graphite-epoxy material studied was Modmor® II graphite/Narmco® 5206 epoxy.
History Dependence in the Cyclic Stress-Strain Response of Wavy Slip Materials
Authors: Laird C , Finney JM , Schwartzman A , de la Veaux R
Published: February 2009

A conflict exists as to whether the saturated flow stress of a wavy slip metal cycled at high plastic strain amplitudes depends on history or not. To resolve this, mechanical tests have been carried out on heavily cold-worked copper and the structures studied by transmission electron microscopy. It has been found that, for any material, there exists a prestrain (dependent on many testing and material factors) below which cyclic stress-strain response is history independent and above which it is dependent. For severe prestrains, the cycling is insufficient to balance the dislocation structures in the cell walls, and the cells are more angular and misoriented than those which occur in annealed metal subjected to strain cycling.
Left-Hand Path Magic and Animal Rights
Authors: Granholm Kennet
Published: February 2009

The Left-Hand Path is a controversial form of new Esoteric spirituality, often labeled Satanic, and often perceived as entertaining right-wing political sympathies. It is therefore important to note that two of the most prominent Left-Hand Path groups—the Temple of Set and Dragon Rouge—foster animal rights ideologies, something which is generally considered leftist. Animal rights ideology would seem to be a less than perfect fit with the epistemological individualism, goals of self-deification, and antinomian approaches to predominant religious culture—fundamental elements in Left-Hand Path philosophies. It has nonetheless become an integral part of both the Temple of Set and Dragon Rouge. In this article I examine the manifestations and possible reasons for the rise of the apparent paradox of animal rights ideologies in the Left-Hand Path.
Reframing Religious Violence after 9/11: Analysis of the ACM Campaign to Exploit the Threat of Terrorism
Authors: Wright Stuart A.
Published: February 2009

This study examines the concerted efforts of anticult movement (ACM) actors to weave narratives of cult brainwashing and mind control into the tragic events of 9/11. Key ACM leaders launched a national media campaign capitalizing on widespread fears and apprehensions surrounding the 9/11 terrorist attacks in an effort to control the framing of the incident as just another form of cult violence and al-Qaeda operatives as brainwashed cultists. By analyzing ACM websites, press releases, media interviews with ACM actors and news stories citing anticult figures as experts, it can be shown how specific framing tasks were employed, targets identified, motives imputed and strategic policy solutions proposed. Indeed, movement activists lobbied to promote the ACM interpretive framework as a master frame and universal strategy to combat radical Islamic terrorism. However, the ACM media campaign was severely hampered by critical social and political obstacles and in the end fell short of movement expectations. The factors impeding movement success are examined and overlapping conceptual issues involving religious movements and terrorism are discussed.
Prophecy and Dissonance: A Reassessment of Research Testing the Festinger Theory
Authors: Stone Jon R.
Published: February 2009

In the fifty years since publication of Festinger's When Prophecy Fails (1956), scholars have reduced the reliability of this study to one statement, namely, that Festinger holds true if, and only if, failed prophecy results in believers actively proselytizing others. This essay takes a different tack. Rather than offer yet another modification to the Festinger thesis, it is the purpose of this essay to suggest additional lines of inquiry that have heretofore been overlooked. After an assessment of a small but representative sample of the research that Festinger has inspired, this essay will outline three alternative research trajectories that interested scholars might fruitfully follow, each related to the original focus of Festinger on prophecy and dissonance. First, dissonance seeking consonance might account for why people join prophetic movements. Second, the resolution of cognitive dissonance might be the occasion for a prophetic utterance rather than the result of a failed prophecy. Third, the existence of multiple prophets within a movement and the rivalries that result appear to heighten dissonance, sometimes undermining the confidence of committed followers.
A Close Look into an Immigrant Workers' Church in Beijing
Authors: Liu Qi
Published: February 2009

Christianity, although a worldwide religious tradition, is counted as a minority in the People's Republic of China (PRC), both by the Christians themselves and by non-believers. "House churches" in the PRC, being illegal and thus underground, are the "minority in a minority." Based on two years of participant-observation, I give a description of the beliefs and rituals of an immigrant workers' Protestant house church system in Beijing. Belief in the Christian God's ability to provide relief from suffering by performing earthly miracles and by bringing the faithful to eternal life in heaven are the main attractions drawing people to the house churches. I argue that the way the believers value and emphasize miracles performed by the Christian God is derived primarily from an orientation found in the Chinese popular religious tradition. Additionally, glorification of suffering in Christianity gives the believers inner strength to face the trials of the world.
Competitive binding of musclin to natriuretic peptide receptor 3 with atrial natriuretic peptide
Authors: Kita Shunbun , Nishizawa Hitoshi , Okuno Yosuke , Tanaka Masaki , Yasui Atsutaka , Matsuda Morihiro , Yamada Yukio , Shimomura Iichiro
Published: February 2009

Musclin is a novel skeletal muscle-derived secretory factor that was isolated by our group. Musclin contains a region homologous to natriuretic peptides (NPs). This study investigated the interaction between musclin and NP receptors (NPRs). Musclin specifically bound to NPR3, but not to NPR1 or NPR2. Musclin and atrial natriuretic peptide (ANP) competed for binding to NPR3. We conducted binding assays using various synthetic musclin peptides and mutant musclin proteins. The first NP-homologous region in musclin (88LDRL91) and the second homologous region (117MDRI120) were responsible cooperatively for high-affinity binding to NPR3. The first NP-homologous region was more importantly associated with binding to NPR3, than the second homologous region. The competitive nature of musclin with ANP for the natriuretic clearance receptor NPR3 was also confirmed in vivo. We conclude that musclin binds to NPR3 competitively with ANP and may affect ANP concentrations in a local or systemic manner.
Forest rodents provide directed dispersal of Jeffrey pine seeds
Authors: Briggs Jennifer S. , Wall Stephen B. Vander , Jenkins Stephen H.
Published: February 2009

Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow‐pine and long‐eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden‐mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio‐labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight‐year period.

Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5–25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a dominant tree species in the eastern Sierra Nevada. Quantifying the occurrence and dynamics of directed dispersal in this and other cases will contribute to better understanding of mutualistic coevolution of plants and animals and to more effective management of ecosystems in which directed dispersal is a keystone process.
Topographic position modulates the mycorrhizal response of oak trees to interannual rainfall variability
Authors: Querejeta JoséI. , Egerton-Warburton Louise M. , Allen Michael F.
Published: February 2009

California coast live oak (Quercus agrifolia) forms tripartite symbiotic associations with arbuscular (AMF) and ectomycorrhizal (EMF) fungi. We selected oak individuals differing in topographic position and depth to groundwater (mesic valley vs. xeric hill sites) to investigate changes of tree mycorrhizal status in response to interannual rainfall variability. EMF root colonization, as well as hyphal abundance and viability in upper rhizosphere soil (0–30 cm), were negatively affected by severe multi‐year drought, although not to the same extent in each topographic location. Oak trees growing in hill sites showed EMF colonization levels <1% in upper roots during drought. By contrast, oaks in valley sites maintained much higher EMF colonization (>19%) in upper roots during drought. EMF root colonization increased sharply at both topographic positions during the ensuing wet year (78% in valley, 49% in hill), which indicates that the mycorrhizal status of roots in upper rhizosphere soil is highly responsive to interannual rainfall variability. Across sites and years, percentage EMF colonization and soil hyphal density and viability were strongly positively correlated with soil moisture potential, but percentage AMF root colonization was not. Interestingly, changes in percentage EMF root colonization and density of viable hyphae between a wet and a dry year were proportionally much greater in xeric hill sites than in mesic valley sites. The mycorrhizal status of oak trees was particularly responsive to changes in soil moisture at the hill sites, where roots in upper rhizosphere soil shifted from almost exclusively AMF during severe drought to predominantly EMF during the ensuing wet year. By contrast, the mycorrhizal status of oaks in the valley sites was less strongly coupled to current meteorological conditions, as roots in upper soil layers remained predominantly EMF during both a dry and a wet year. Canopy shading and hydraulic lift by oaks in valley sites likely contributed to maintain the integrity and viability of EMF roots and extraradical hyphae in upper rhizosphere soil during extended drought. Our results suggest that oak woodlands in water‐limited ecosystems may become increasingly reliant on the AMF symbiosis under future climate change scenarios for the U.S. southwest and other world regions.
Partitioning beta diversity in a subtropical broad‐leaved forest of China
Authors: Legendre Pierre , Mi Xiangcheng , Ren Haibao , Ma Keping , Yu Mingjian , Sun I-Fang , He Fangliang
Published: February 2009

The classical environmental control model assumes that species distribution is determined by the spatial variation of underlying habitat conditions. This niche‐based model has recently been challenged by the neutral theory of biodiversity which assumes that ecological drift is a key process regulating species coexistence. Understanding the mechanisms that maintain biodiversity in communities critically depends on our ability to decompose the variation of diversity into the contributions of different processes affecting it. Here we investigated the effects of pure habitat, pure spatial, and spatially structured habitat processes on the distributions of species richness and species composition in a recently established 24‐ha stem‐mapping plot in the subtropical evergreen broad‐leaved forest of Gutianshan National Nature Reserve in East China. We used the new spatial analysis method of principal coordinates of neighbor matrices (PCNM) to disentangle the contributions of these processes. The results showed that (1) habitat and space jointly explained ∼53% of the variation in richness and ∼65% of the variation in species composition, depending on the scale (sampling unit size); (2) tree diversity (richness and composition) in the Gutianshan forest was dominantly controlled by spatially structured habitat (24%) and habitat‐independent spatial component (29%); the spatially independent habitat contributed a negligible effect (6%); (3) distributions of richness and species composition were strongly affected by altitude and terrain convexity, while the effects of slope and aspect were weak; (4) the spatial distribution of diversity in the forest was dominated by broad‐scaled spatial variation; (5) environmental control on the one hand and unexplained spatial variation on the other (unmeasured environmental variables and neutral processes) corresponded to spatial structures with different scales in the Gutianshan forest plot; and (6) five habitat types were recognized; a few species were statistically significant indicators of three of these habitats, whereas two habitats had no significant indicator species. The results suggest that the diversity of the forest is equally governed by environmental control (30%) and neutral processes (29%). In the fine‐scale analysis (10 × 10 m cells), neutral processes dominated (43%) over environmental control (20%).
Diversity effects in early‐ and mid‐successional species pools along a nitrogen gradient
Authors: Wacker Luca , Baudois Oksana , Eichenberger-Glinz Susann , Schmid Bernhard
Published: February 2009

Biodiversity experiments with grassland species have shown that plant productivity commonly increases with species richness and that this increase can be stronger in nutrient‐rich than in nutrient‐poor environments. It has been suggested that these effects are due to functional diversity among species. To investigate this, we established five early‐ and five mid‐successional pools of six species each, expecting stronger effects in the latter. The 10 six‐species mixtures and the 60 corresponding species monocultures were grown at four levels of soil nitrogen. We used five species traits (plant length, leaf length, leaf tissue density, specific leaf area, leaf nitrogen concentration) to calculate a functional diversity index weighted by relative species densities in mixture (Qd/m). This functional diversity index and aboveground biomass production (standing crop at end of experiment) in mixture were similar between early‐ and mid‐successional communities but varied among communities within successional status. Mixture biomass was between the mean and maximum monoculture biomass, indicating that the latter species did not dominate mixtures and complementarity was not strong enough to cause transgressive overyielding. As expected, high mixture biomass was positively correlated withQd/m. Also as expected, net biodiversity effects (mixture–mean monoculture biomass) were stronger in mid‐ than in early‐successional pools. Net biodiversity effects increased with nitrogen level in some pools but decreased in others. The increase was consistent with a marginally positive effect of nitrogen level on functional diversity and a positive relation between functional diversity and net biodiversity effect.
Coexistence and limiting similarity of consumer species competing for a linear array of resources
Authors: Abrams Peter A. , Rueffler Claus
Published: February 2009

Consumer–resource systems with linear arrays of substitutable resources form the conceptual basis of much of present‐day competition theory. However, most analyses of the limiting similarity of competitors have only employed consumer–resource models as a justification for using the Lotka‐Volterra competition equations to represent the interaction. Unfortunately, Lotka‐Volterra models cannot reflect resource exclusion via apparent competition and are poor approximations of systems with nonlogistic resource growth. We use consumer–resource models to examine the impact of exclusion of biotic resources or depletion of abiotic resources on the ability of three consumer species to coexist along a one‐dimensional resource axis. For a wide range of consumer–resource models, coexistence conditions can become more restrictive with increasing niche separation of the two outer species. This occurs when the outer species are highly efficient; in this case they cause extinction or severe depletion of intermediate resources when their own niches have an intermediate level of separation. In many cases coexistence of an intermediate consumer species is prohibited when niche separation of the two outer species is moderately large, but not when it is small. Coexistence may be most likely when the intermediate species is closer to one of the two outer species, contrary to previous theory. These results suggest that competition may lead to uneven spacing of utilization curves. The implications and range of applicability of the models are discussed.
Temporal scales, trade‐offs, and functional responses in red deer habitat selection
Authors: Godvik Inger Maren Rivrud , Loe Leif Egil , Vik Jon Olav , Veiberg VebjØrn , Langvatn Rolf , Mysterud Atle
Published: February 2009

Animals selecting habitats often have to consider many factors, e.g., food and cover for safety. However, each habitat type often lacks an adequate mixture of these factors. Analyses of habitat selection using resource selection functions (RSFs) for animal radiotelemetry data typically ignore trade‐offs, and the fact that these may change during an animal's daily foraging and resting rhythm on a short‐term basis. This may lead to changes in the relative use of habitat types if availability differs among individual home ranges, called functional responses in habitat selection. Here, we identify such functional responses and their underlying behavioral mechanisms by estimating RSFs through mixed‐effects logistic regression of telemetry data on 62 female red deer (Cervus elaphus) in Norway. Habitat selection changed with time of day and activity, suggesting a trade‐off in habitat selection related to forage quantity or quality vs. shelter. Red deer frequently used pastures offering abundant forage and little canopy cover during nighttime when actively foraging, while spending much of their time in forested habitats with less forage but more cover during daytime when they are more often inactive. Selection for pastures was higher when availability was low and decreased with increasing availability. Moreover, we show for the first time that in the real world with forest habitats also containing some forage, there was both increasing selection of pastures (i.e., not proportional use) and reduced time spent in pastures (i.e., not constant time use) with lowered availability of pastures within the home range. Our study demonstrates that landscape‐level habitat composition modifies the trade‐off between food and cover for large herbivorous mammals. Consequently, landscapes are likely to differ in their vulnerability to crop damage and threat to biodiversity from grazing.
Species richness and temperature influence mussel biomass: a partitioning approach applied to natural communities
Authors: Spooner Daniel E. , Vaughn Caryn C.
Published: February 2009

To increase the generality of biodiversity–ecosystem function theory, studies must be expanded to include real communities in a variety of systems. We modified J. W. Fox's approach to partition the influence of species richness on standing crop biomass (net biodiversity effect) of 21 freshwater mussel communities into trait‐independent complementarity, trait‐dependent complementarity (species with particular traits dominate without impacting other species), and dominance effects (species with particular traits dominate at the expense of others). Overall, species‐rich mussel communities have greater biomass than predicted based on average biomass across the region. This effect is largely due to trait‐independent complementarity with less abundant species having higher body condition and reduced metabolic rates in species‐rich communities. These measures are positively correlated with spatial and temporal thermal variation, suggesting that use of thermal niches as habitat may be important to species coexistence and performance, and emphasizing that knowledge of species traits and environmental context are important to understanding biodiversity–ecosystem function dynamics.