bluuebunny/crossref_metadata_2025 huggingface dataset:
An Automated Apparatus for Three-Dimensional Monotonic and Cyclic Testing of Interfaces
Authors: Fakharian K , Evgin E
Published: February 2009

A new computer-controlled apparatus has been developed to study the behavior of interfaces between two materials under three-dimensional monotonic and cyclic loading conditions. The interface can be subjected to a normal stress, σn, and two shear stresses, τx, and τy, acting simultaneously on the interface plane. The normal stress is applied by a pneumatic actuator that is operated by a motorized regulator. Shear stresses, which are perpendicular to each other, are applied by two stepper motors. Tests can be either displacement or load controlled.

The results of an experimental program that includes two series of tests to study the behavior of an interface between a dry coarse sand and a rough surface are presented. In the first series, two-dimensional monotonic and cyclic tests were carried out to verify the performance of the apparatus. The effects of surface roughness, initial relative density of sand, and the magnitude of normal stress on the shear stress-shear displacement and volume change behavior of the interface are presented. In the second series, the loading was three-dimensional and monotonic. First, the interface was sheared in one tangential direction up to a shear stress level less than the peak value. Then, the interface was sheared in a perpendicular direction, while the shear stress in the previous direction was maintained at a constant level. Shear stress and shear displacement increments experienced different paths, while the resultant shear stress-shear displacement curves remained the same irrespective of stress paths.
Determining Bentonite Content in Soil-Bentonite Mixtures Using Electrical Conductivity
Authors: Abu-Hassanein ZS , Benson CH , Wang X , Blotz LR
Published: February 2009

A procedure based on electrical conductivity is described for measuring bentonite content in soil-bentonite mixtures having a wide range of bentonite contents. Standard equipment used for sedimentation analysis and an electrical conductivity meter are required. The procedure employs calibration curves relating electrical conductivity and bentonite concentration for soil-bentonite-water slurries. Calibration curves are presented for two sand-bentonite mixtures, a mixture of bentonite and waste mine rock, and two fine-grained soils mixed with bentonite.
Water Pressure Measurement with Time Domain Reflectometry Cables
Authors: Dowding CH , Huang F , McComb PS
Published: February 2009

Attributes of the remote measurement of piezometric water pressure and water level with time domain reflectometry (TDR) techniques are investigated. The evaluation includes a two-wire system for unusually small riser tubes as well as parallel wire and air-filled or hollow coaxial cable for typical installations. Comparison of TDR cable and commercial pressure transducer technology shows coaxial cable TDR systems with distance crimps capable of equaling and exceeding the resolution of pressure transducers. Crimps provide permanent distance markers that allow the TDR system to be self-calibrating.
Pressuremeter Testing in Arid Collapsible Soils
Authors: Smith TD , Rollins KM
Published: February 2009

An introduction to soil mechanics limitations, testing concerns, and deposition of collapsible soil from the arid western states in the U.S. is presented. Laboratory evaluation of their properties for routine foundation engineering bearing capacity and settlement is of limited use. In situ testing is shown to be practical and successful in a wide range of soil types from uniform fine-grained soils to silty-sandy gravels. The hydraulic, monocell, prebored pressuremeter is proposed as an in situ test to establish dry, wet, and dry-wet geotechnical parameters for design by three testing procedures. Each procedure is given a detailed description, typical results are presented for collapsible debris fan deposits, and application of the procedures to routine foundation design is discussed. Simple collapse categories are introduced based on the pressurementer stiffness change from dry to wet conditions. Two minor modifications to the commercial pressuremeter probe end shoe and top support collar are recommended to ensure uniform radial water migration. Estimates of the depth of collapse from subsurface soil beneath existing foundations undergoing excessive settlement are also possible.
Comparison of Laboratory-Measured GCL Hydraulic Conductivity Based on Three Permeameter Types
Authors: Petrov RJ , Kerry Rowe R , Quigley RM
Published: February 2009

Specimen preparation, installation, and testing procedures are presented for testing a needle-punched geosynthetic clay liner (GCL) in a consolidation-type, fixed-ring constant-flow-rate hydraulic conductivity apparatus. The proposed approach is illustrated by reporting the results obtained for a GCL statically confined to effective stresses of ∼3 and ∼35 kPa, hydrated and permeated with distilled water and concentrated aqueous salt solutions (0.6 and 2.0 N NaCl), and sequentially permeated with concentrated aqueous salt solutions (0.6 and 2.0 N NaCl) after initial permeation with distilled water. The issue of potential preferential sidewall flow in the fixed-ring permeameter tests was then addressed by comparing results with those conducted under otherwise similar testing conditions in a double-ring and flexible-wall permeameter. Reasonable reproducibility of the test results was obtained between the different types of permeameters, suggesting that, if present, preferential sidewall flow was negligibly small and was not significant on the calculated hydraulic conductivity values. This conclusion was found to be valid for the range of permeant types (distilled water and 0.6 and 2.0 N NaCl), static-confining stresses, and hydrating mediums considered. Premature arrival of the salt solution front in the effluent (i.e., solute breakthrough) during fixed-ring hydraulic conductivity testing was explained as a probable diffusion-dominated transport mechanism through the relatively thin GCL specimens.
Particle-Size Analysis of Soils Using Laser Light Scattering and X-Ray Absorption Technology
Authors: Vitton SJ , Sadler LY
Published: February 2009

The particle-size distribution for the fine-grained fraction of eleven soil samples was determined using four commercially available, state-of-the-art automated particle-size distribution analysis instruments. Two of the instruments operate on the principle of interaction of laser light with soil particles suspended in water in a highly agitated state, and two operate on the principle of the absorption of an X-ray beam by a suspension of soil particles settling in a quiescent column of water. The results from each instrument for each soil sample were compared to size analysis data determined by the hydrometer technique. The X-ray absorption instruments produced particle-size distributions very close to those of the hydrometer method, with the exception of soils with high mica concentrations. The laser-based instrument data did not agree as well with the hydrometer data, although for soils with significant mica contents the results were closer than the results from the X-ray absorption instruments. Based on these results, however, it appears that the automated X-ray absorption/sedimentation-based instruments show promise as alternatives or as a possible supplement for the manual hydrometer method of size analysis for soils without significant mica particle concentrations.
Experimental Nailed Soil Walls
Authors: Ramalinga Raju GV , Wong IH , Low BK
Published: February 2009

Normal gravity model tests were carried out in a trench to study the influence of several design parameters on the behavior of nailed soil-retaining walls. Six nailed walls were built by varying the nail length, nail inclination, and the method of nail installation. The construction of each wall involved gradual placement of 36 m3 of sand using a clamshell attached to an overhead traveling crane, followed by excavation (in front of the facing) and installation of model soil nails. Each completed nailed soil wall and its retained sand measured 3.0 by 3.0 m in plan and was 2.4 m high before placement of surcharge fill. This paper describes the method adopted for reducing side wall friction, the sand placement procedure, the checks on uniformity and reproducibility of the relative density of the sand, the instrumentation, and the stage-by-stage excavation and nailing process. A summary of monitored results of all the tests is presented, and the results of Test 1 are discussed in detail.
Influence of Intersection Angle at Single-Well Flow Tests in Fracture-Wellbore Systems
Authors: Aydin A
Published: February 2009

The intersection angle between a hydraulically effective fracture and an active wellbore influences the response observed in single-well tests. An experimental study was launched to investigate the ability of a semi-analytical model proposed to account for this influence. The setup designed for this purpose includes three distinct fracture-wellbore system models with 90°, 20°, and 10° intersection angles, each assembled into a steel box frame to provide a constant fracture aperture during testing. The laboratory program involved testing each of these models for three different fracture apertures under steady, constant-flux, injection, and pumping conditions. The overall experimental setup successfully simulated the conceptual testing environment in which the mathematical model is expected to reproduce. Analysis of the test results confirmed the effectiveness of the conceptual model in refining the predictions of single-well tests. Important applications include the determination of anisotropic rock-mass permeability in a single, arbitrarily oriented wellbore by isolating fractures of different sets and of optimum wellbore orientation and spacing for maximum efficiency of producing wells.
Improved √t Method to Evaluate Consolidation Test Results
Authors: Tewatia SK , Venkatachalam K
Published: February 2009

Taylor (1948) suggested the method for determination of the settlement, δ, corresponding to 90% consolidation utilizing the characteristics of the degree of consolidation, U, versus the square root of the time factor, √T, plot. Based on the properties of the slope of U versus √T curve, a new method is proposed to determine δ corresponding to any U above 70% consolidation for evaluation of the coefficient of consolidation, Cv. The effects of the secondary consolidation on the Cv value at different percentages of consolidation can be studied. Cv, closer to the field values, can be determined in less time as compared to Taylor's method. At any U in between 75 and 95% consolidation, Cv(U) due to the new method lies in between Taylor's Cv and Casagrande's Cv.
Book Review
Authors: Fourney WL
Published: February 2009

The purpose of this book is to demonstrate the use of fracture mechanics in describing structural behavior leading to failure of quasi-brittle materials. It is intended as a textbook for a graduate course in civil engineering, engineering mechanics, or allied disciplines. It could be used as a supplementary text for courses in advanced concrete theory and as a reference text for the practicing engineer. It draws upon the research findings of the authors and others over the last two decades in the applications of fracture mechanics as applied to cracking, damage, and fracture of plain and reinforced concrete structures and rock masses.
Revised Incremental J-Integral Equations for ASTM E1820 Using the Crack Mouth Opening Displacement
Authors: Zhu Xian-Kui , Joyce James A.
Published: February 2009

The incremental J-integral equations used in ASTM E1820 were developed utilizing the work input to the test specimen, and utilize the load versus load-point/line displacement (LLD) data obtained from the fracture test. The analysis of Ernst et al. [Fracture Machanics: Thirteenth Conference, ASTM STP 743] was then used to obtain crack growth corrected estimates of the J-integral as needed for an accurate J-R curve evaluation. For the compact type specimens, the crack mouth opening displacement (CMOD) gage was moved to the load line so that an adequate estimate of LLD could be obtained from the clip gage and utilized for compliance-based crack extension and incremental J-integral estimates. For the single edge-notched bend [SE(B)] specimens, however, it has been necessary to measure both CMOD for compliance-based crack length estimates and LLD for the crack growth corrected J-integral calculations. Additional experimental complexity and expense are thus added. ASTM E1820 includes a “basic” procedure which allows evaluating the J-integral using CMOD without crack growth corrections if the result is used only for evaluation of initiation toughness. Recently, Annex A16 based on work of Wallin and Laukkanen [Engineering Fracture Mechanics, Vol. 71, 2004, pp. 1601–1614] has been added to ASTM E1820 that presents a multiple-step procedure to obtain a crack growth corrected J-R curve from the basic method data. A more direct approach was proposed recently by Zhu et al. [Journal of ASTM International, Vol. 5, No. 5, 2008, paper ID: JAI 101532] using an incremental procedure to obtain the desired, crack growth corrected J-R curve from the CMOD data of SE(B) specimens with two geometry factors ηCMOD and γCMOD similar to the parameters presently used in the existing LLD-based J-integral analysis. Using fracture toughness test data for SE(B) specimens, detailed comparisons and discussions are made between the proposed method and the ASTM E1820 CMOD methods in determination of J-R curves for HY80 steels. As the basis of comparison, the “accurate” solutions obtained from the standard LLD-based incremental J-integral method are provided for all specimens considered. The difference between the CMOD and LLD methods are then quantified. The results show that the proposed CMOD incremental J-integral equations are simple and effective, and thus are recommended here for use in ASTM E1820 for testing J-R curves and for reducing test costs and complexity.
Timescale-Invariant Representation of Acoustic Communication Signals by a Bursting Neuron
Authors: Creutzig Felix , Wohlgemuth Sandra , Stumpner Andreas , Benda Jan , Ronacher Bernhard , Herz Andreas V. M.
Published: February 2009

Acoustic communication often involves complex sound motifs in which the relative durations of individual elements, but not their absolute durations, convey meaning. Decoding such signals requires an explicit or implicit calculation of the ratios between time intervals. Using grasshopper communication as a model, we demonstrate how this seemingly difficult computation can be solved in real time by a small set of auditory neurons. One of these cells, an ascending interneuron, generates bursts of action potentials in response to the rhythmic syllable–pause structure of grasshopper calls. Our data show that these bursts are preferentially triggered at syllable onset; the number of spikes within the burst is linearly correlated with the duration of the preceding pause. Integrating the number of spikes over a fixed time window therefore leads to a total spike count that reflects the characteristic syllable-to-pause ratio of the species while being invariant to playing back the call faster or slower. Such a timescale-invariant recognition is essential under natural conditions, because grasshoppers do not thermoregulate; the call of a sender sitting in the shade will be slower than that of a grasshopper in the sun. Our results show that timescale-invariant stimulus recognition can be implemented at the single-cell level without directly calculating the ratio between pulse and interpulse durations.
Glycine Inhibitory Dysfunction Induces a Selectively Dynamic, Morphine-Resistant, and Neurokinin 1 Receptor- Independent Mechanical Allodynia
Authors: Miraucourt Loïs S. , Moisset Xavier , Dallel Radhouane , Voisin Daniel L.
Published: February 2009

Dynamic mechanical allodynia is a widespread and intractable symptom of neuropathic pain for which there is a lack of effective therapy. We recently provided a novel perspective on the mechanisms of this symptom by showing that a simple switch in trigeminal glycine synaptic inhibition can turn touch into pain by unmasking innocuous input to superficial dorsal horn nociceptive specific neurons through a local excitatory, NMDA-dependent neural circuit involving neurons expressing the gamma isoform of protein kinase C. Here, we further investigated the clinical relevance and processing of glycine disinhibition. First, we showed that glycine disinhibition with strychnine selectively induced dynamic but not static mechanical allodynia. The induced allodynia was resistant to morphine. Second, morphine did not prevent the activation of the neural circuit underlying allodynia as shown by study of Fos expression and extracellular-signal regulated kinase phosphorylation in dorsal horn neurons. Third, in contrast to intradermal capsaicin injections, light, dynamic mechanical stimuli applied under disinhibition did not produce neurokinin 1 (NK1) receptor internalization in dorsal horn neurons. Finally, light, dynamic mechanical stimuli applied under disinhibition induced Fos expression only in neurons that did not express NK1 receptor. To summarize, the selectivity and morphine resistance of the glycine-disinhibition paradigm adequately reflect the clinical characteristics of dynamic mechanical allodynia. The present findings thus reveal the involvement of a selective dorsal horn circuit in dynamic mechanical allodynia, which operates through superficial lamina nociceptive-specific neurons that do not bear NK1 receptor and provide an explanation for the differences in the pharmacological sensitivity of neuropathic pain symptoms.
Membrane Lipid Modulations Remove Divalent Open Channel Block from TRP-Like and NMDA Channels
Authors: Parnas Moshe , Katz Ben , Lev Shaya , Tzarfaty Vered , Dadon Daniela , Gordon-Shaag Ariela , Metzner Henry , Yaka Rami , Minke Baruch
Published: February 2009

Open channel block is a process in which ions bound to the inside of a channel pore block the flow of ions through that channel. Repulsion of the blocking ions by depolarization is a known mechanism of open channel block removal. For the NMDA channel, this mechanism is necessary for channel activation and is involved in neuronal plasticity. Several types of transient receptor potential (TRP) channels, including theDrosophilaTRP and TRP-like (TRPL) channels, also exhibit open channel block. Therefore, removal of open channel block is necessary for the production of the physiological response to light. Because there is no membrane depolarization before the light response develops, it is not clear how the open channel block is removed, an essential step for the production of a robust light response under physiological conditions. Here we present a novel mechanism to alleviate open channel block in the absence of depolarization by membrane lipid modulations. The results of this study show open channel block removal by membrane lipid modulations in both TRPL and NMDA channels of the photoreceptor cells and CA1 hippocampal neurons, respectively. Removal of open channel block is characterized by an increase in the passage-rate of the blocking cations through the channel pore. We propose that the profound effect of membrane lipid modulations on open channel block alleviation, allows the productions of a robust current in response to light in the absence of depolarization.
Neuregulin Signaling Is Dispensable for NMDA- and GABAA-Receptor Expression in the CerebellumIn Vivo
Authors: Gajendran N. , Kapfhammer J. P. , Lain E. , Canepari M. , Vogt K. , Wisden W. , Brenner H. R.
Published: February 2009

Neuregulin-1s (NRG-1s) are a family of growth and differentiation factors with multiple roles in the development and function in different organs including the nervous system. Among the proposed functions of NRG-1s in the nervous system is the regulation of genes encoding certain neurotransmitter receptors during synapse formation as well as of other aspects of synaptic function. Here, we have examined, in granule cells of the cerebellumin vivo, the role of NRGs in the induction of NMDA receptor (NMDA-R) and GABAAreceptor (GABAA-R), which are thought to be induced by NRG-1 secreted by the synaptic inputs. To this end, we used the Cre/loxP system to genetically ablate the NRG receptors ErbB2 and ErbB4 selectively in these cells, thus eliminating all NRG-mediated signaling to them. Unlike previous reports using cultured granule cells to address the same question, we found that the developmental expression patterns of the mRNAs encoding the NR2C subunit of the NMDA-R and the β2-subunit of the GABAA-R is normal in mice lacking the NRG receptors ErbB2 and ErbB4. Likewise, no alterations in cerebellar morphology nor in certain aspects of cerebellar wiring were resolved in these mutants. We conclude that NRG/ErbB signaling to the granule cells is dispensable for the normal development of their synaptic inputs.
A Role for Calmodulin-Stimulated Adenylyl Cyclases in Cocaine Sensitization
Authors: DiRocco Derek P. , Scheiner Zachary S. , Sindreu Carlos Balet , Chan Guy C.-K. , Storm Daniel R.
Published: February 2009

Cocaine sensitization is produced by repeated exposure to the drug and is thought to reflect neuroadaptations that contribute to addiction. Here, we identify the Ca2+/calmodulin-stimulated adenylyl cyclases, type 1 (AC1) and type 8 (AC8), as novel regulators of this behavioral plasticity. We show that, whereas AC1 and AC8 single knock-out mice (AC1−/−andAC8−/−) exhibit Ca2+-stimulated adenylyl cyclase activity in striatal membrane fractions, AC1/8 double-knock-out (DKO) mice do not. Furthermore, DKO mice are acutely supersensitive to low doses of cocaine and fail to display locomotor sensitization after chronic cocaine treatment. Because of the known role for the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase signaling pathway in cocaine-induced behavioral plasticity and its coupling to calcium-stimulated cAMP signaling in the hippocampus, we measured phosphorylated ERK (pERK) levels in the striatum. Under basal conditions, pERK is upregulated in choline acetyltransferase-positive interneurons in DKO mice relative to wild-type (WT) controls. After acute cocaine treatment, pERK signaling is significantly suppressed in medium spiny neurons (MSNs) of DKO mice relative to WT mice. In addition to the lack of striatal ERK activation by acute cocaine, signaling machinery downstream of ERK is uncoupled in DKO mice. We demonstrate that AC1 and AC8 are necessary for the phosphorylation of mitogen and stress-activated kinase-1 (pMSK1) at Ser376 and Thr581 and cAMP response element-binding protein (pCREB) at Ser133 after acute cocaine treatment. Our results demonstrate that the Ca2+-stimulated adenylyl cyclases regulate long-lasting cocaine-induced behavioral plasticity via activation of the ERK/MSK1/CREB signaling pathway in striatonigral MSNs.
Early Bilateral Sensory Deprivation Blocks the Development of Coincident Discharge in Rat Barrel Cortex
Authors: Ghoshal Ayan , Pouget Pierre , Popescu Maria , Ebner Ford
Published: February 2009

Several theories have proposed a functional role for synchronous neuronal firing in generating the neural code of a sensory perception. Synchronous neural activity develops during a critical postnatal period of cortical maturation, and severely reducing neural activity in a sensory pathway during this period could interfere with the development of coincident discharge among cortical neurons. Loss of such synchrony could provide a fundamental mechanism for the degradation of acuity shown in behavioral studies. We tested the hypothesis that synchronous discharge of barrel cortex neurons would fail to develop after sensory deprivation produced by bilateral whisker trimming from birth to postnatal day 60. By studying the correlated discharge of cortical neuron pairs, we found evidence for strong correlated firing in control animals, and this synchrony was almost absent among pairs of cortical barrel neurons in deprived animals. The degree of synchrony impairment was different in subregions of rat barrel cortex. The model that best fits the data is that cortical neurons receiving direct inputs from the primary sensory (lemniscal) pathway show the greatest decrement in synchrony following sensory deprivation, while neurons with diverse inputs from other areas of thalamus and cortex are relatively less affected in this dimension of cortical function.
L-Type Calcium Channels Govern Calcium Signaling in Migrating Newborn Neurons in the Postnatal Olfactory Bulb
Authors: Darcy Daniel P. , Isaacson Jeffry S.
Published: February 2009

Newborn inhibitory neurons migrate into existing neural circuitry in the olfactory bulb throughout the lifetime of adult mammals. While many factors contribute to the maturation of neural circuits, intracellular calcium is believed to play an important role in regulating cell migration and the development of neural systems. However, the factors underlying calcium signaling within newborn neurons in the postnatal olfactory bulb are not well understood. Here, we show that migrating, immature neurons in the olfactory bulb subependymal layer (SEL) undergo spontaneous and depolarization-evoked intracellular calcium transients mediated by high-voltage-activated L-type calcium channels. In contrast to migrating immature neurons in other brain regions, modulation of calcium transients in SEL cells does not alter their rate of migration.
Glucose Inhibition Persists in Hypothalamic Neurons Lacking Tandem-Pore K+Channels
Authors: Guyon Alice , Tardy Magalie P. , Rovère Carole , Nahon Jean-Louis , Barhanin Jacques , Lesage Florian
Published: February 2009

Glucose sensing by hypothalamic neurons triggers adaptive metabolic and behavioral responses. In orexin neurons, extracellular glucose activates a leak K+current promoting electrical activity inhibition. Sensitivity to external acidification and halothane, and resistance to ruthenium red designated the tandem-pore K+(K2P) channel subunit TASK3 as part of the glucose-induced channel. Here, we show that glucose inhibition and its pH sensitivity persist in mice lacking TASK3 or TASK1, or both subunits. We also tested the implication of another class of K2Pchannels activated by halothane. In the corresponding TREK1/2/TRAAK triple knock-out mice, glucose inhibition persisted in hypothalamic neurons ruling out a major contribution of these subunits to the glucose-activated K+conductance. Finally, block of this glucose-induced hyperpolarizing current by low Ba2+concentrations was consistent with the conclusion that K2Pchannels are not required for glucosensing in hypothalamic neurons.
Developmental Shift of Cyclophilin D Contribution to Hypoxic-Ischemic Brain Injury
Authors: Wang Xiaoyang , Carlsson Ylva , Basso Emy , Zhu Changlian , Rousset Catherine I. , Rasola Andrea , Johansson Bengt R. , Blomgren Klas , Mallard Carina , Bernardi Paolo , Forte Michael A. , Hagberg Henrik
Published: February 2009

Cyclophilin D (CypD), a regulator of the mitochondrial membrane permeability transition pore (PTP), enhances Ca2+-induced mitochondrial permeabilization and cell death in the brain. However, the role of CypD in hypoxic-ischemic (HI) brain injury at different developmental ages is unknown. At postnatal day (P) 9 or P60, littermates of CypD-deficient [knock-out (KO)], wild-type (WT), and heterozygous mice were subjected to HI, and brain injury was evaluated 7 d after HI. CypD deficiency resulted in a significant reduction of HI brain injury at P60 but worsened injury at P9. After HI, caspase-dependent and -independent cell death pathways were more induced in P9 CypD KO mice than in WT controls, and apoptotic activation was minimal at P60. The PTP had a considerably higher induction threshold and lower sensitivity to cyclosporin A in neonatal versus adult mice. On the contrary, Bax inhibition markedly reduced caspase activation and brain injury in immature mice but was ineffective in the adult brain. Our findings suggest that CypD/PTP is critical for the development of brain injury in the adult, whereas Bax-dependent mechanisms prevail in the immature brain. The role of CypD in HI shifts from a predominantly prosurvival protein in the immature to a cell death mediator in the adult brain.
Evidence of a Housing Decision Chain in Rural Community Vitality*
Authors: Cook Christine C. , Crull Sue R. , Bruin Marilyn J. , Yust Becky L. , Shelley Mack C. , Laux Sharon , Memken Jean , Niemeyer Shirley , White B. J.
Published: February 2009

Abstract  The purpose of this research was to explore and explain the role housing plays in rural community vitality. Community vitality refers to economic strength and social well‐being. In spring 2002 we collected primary interview data from informants in 134 small rural communities in nine north‐central states and identified related secondary data from the U.S. census. We developed a structural‐equation‐path model, which supported a “housing decision chain” that influenced community vitality. Based on this research, local housing decisions do play an important role in community vitality. Strong local leaders use housing planning to secure funding to produce a change in the quantity of housing, which in turn positively influences community vitality. Housing inventory also mediated the effects of total population and percentage population change on community vitality, indicating that housing supply is a fundamental ingredient in community growth strategies. These findings support the conclusion that a combination of housing plans and strategies orchestrated by skilled, committed leadership strengthens rural communities. Heretofore the ling between housing and community vitality has not been investigated; evidence‐based data has been missing from the debate on viable rural community‐development strategies.
Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B
Authors: Zenaty D , Aigrain Y , Peuchmaur M , Philippe-Chomette P , Baumann C , Cornelis F , Hugot J P , Chevenne D , Barbu V , Guillausseau P J , Schlumberger M , Carel J C , Travagli J P , Léger J
Published: February 2009

Context

Early prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy.

Objective

To analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome.

Design and setting

A university hospital-based prospective study from 2001 to 2008.

Subjects and methods

Six family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening.

Results

Total thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC.

Conclusion

Bilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.
New ways of higher education in nursing: globalisation of nursing leadership and its teaching – Dual degree in nursing
Authors: Pop Marcel , Hollós Sándor , Vingender István , Mészáros Judit
Published: February 2009

Our paper is presenting a new initiative regarding an international cooperation willing to develop a dual degree program in nursing, the so-called Transatlantic Curriculum in Nursing. The candidates – after successful completion of their studies – will get a European and an American partner diploma in nursing. The objective is to prepare an internationally and culturally competent workforce; develop the practice of nursing students’ exchange programs; process the model of dual degree independent of geographical, political or cultural borders; spread the evidence-based nursing standards in the daily practice. The partners in this initiative are Semmelweis University in Budapest, Hungary, Nazareth College of Rochester, NY, USA and Laurea University in Tikkurila, Finland. The planned activities in the framework of the program: mutual student and staff mobility, joint curriculum development and teaching process, determining joint standards. The expected outcomes are: to develop a standardised model for the enhancement and implementation of international educational programs in nursing; to improve institutional work culture; to improve professional terminology and cultural abilities; to create the model of a new type of nursing professional having a high level of cultural and language competence which are indispensable for participating in global programs.
Movement and Recolonization of Potomac Sculpin in a Virginia Stream
Authors: Hudy Mark , Shiflet Jeremy
Published: February 2009

Movement patterns of benthic fishes have not been widely studied, but an understanding of those movement patterns may be necessary in assessing the full effects of habitat fragmentation and the need to restore connectivity in fragmented watersheds. We evaluated nonspawning movement of 3,353 marked Potomac sculpin Cottus girardi over a 1-year period on a 3.14-km segment of a third-order stream. In addition, we conducted a fish removal experiment at the pool–riffle sequence scale (90 m) to evaluate the effects of fish density on movement and recolonization rates. The majority of recaptured Potomac sculpin stayed within 30 m of their original capture location throughout the study (81% at 30 d; 64% at 75 d; 53% at 363 d). Upstream (US) movement was greater than downstream (DS) movement at 30 d (US 17%; DS 3%), 75 d (US 30%, DS 6%) and 363 d (US 32%, DS 15%). After 75 d, 10% of the fish that moved upstream moved more than 250 m (21% after 363 d). The maximum distance moved was 1,711 m in 75 d. There were no significant differences in mean total length between recaptured Potomac sculpin that either moved or did not move or between upstream and downstream movers. The presence or absence of fishes in adjacent 30-m habitat sections influenced upstream, but not downstream, movement of Potomac sculpin. After 30 d, Potomac sculpin population densities and size structure were similar between fish removal and reference sections. We found our results to be similar to those of other studies, which found that, on average, freshwater sculpin are sedentary. However, we identified great dispersal capabilities (>250 m) for a small percentage of Potomac sculpin. The long dispersal distances suggest that this typically sedentary species may need greater habitat connectivity than previously assumed.
Will It Float? Testing a New Technique for Reducing Loggerhead Sea Turtle Damage to Crab Pots
Authors: Avissar Naomi , Hazen Elliott , Young Nancy , Crowder Larry
Published: February 2009

Loggerhead sea turtles Caretta caretta have been found to damage crab pots and reduce catch of blue crabs Callinectes sapidus in North Carolina sounds. In response, crabbers have avoided fishing at locations and times of peak loggerhead sea turtle activity and have experimented with modifications to make their gear more robust. We field tested a new, lightweight, and inexpensive modification: self-righting floats tethered to the inside of the crab pots. Thirty pairs of regular and modified pots were fished between 16 June and 31 July 2006. Damage by loggerhead sea turtles was found in 38% of all replicates, and blue crab catch was 57% lower in crab pots that had been discovered by loggerhead sea turtles. The float modification effectively reduced damage, but stronger effects were found when using plastic bait-well covers that the crabbers had introduced. The modified pots were significantly less damaged (average damage index [ADI] = 1.38 with plastic covers and 2.01 with cardboard covers) than regular pots (ADI = 1.78 with plastic covers and 2.38 with cardboard covers). Average blue crab catch was significantly higher in pots with plastic bait-well covers (15 crabs/modified pot, 18 crabs/regular pot) than in pots with cardboard covers (13 crabs/modified pot, 11 crabs/regular pot). However, there was a significant interaction of pot type with bait-well cover type. When plastic covers were used, average blue crab catch was higher in regular pots (18 crabs/pot) than in modified pots (15 crabs/pot). The opposite case was observed when cardboard covers were used: catch was higher in modified pots (13 crabs/pot) than in regular pots (11 crabs/pot). A drawback to the float modification was a qualitative increase in pot drift and loss in high winds, resulting in the need for costly retrieval measures; crab pot loss may also jeopardize estuarine species that become trapped in derelict gear. Adopting these techniques, however, may help crabbers reduce gear damage, catch loss, and negative interactions with loggerhead sea turtles in this fishery.
Effectiveness of Salmon Carcass Tissue for Use in DNA Extraction and Amplification in Conservation Genetic Studies
Authors: Baumsteiger Jason , Kerby Jacob L.
Published: February 2009

A key concern in conservation genetic studies is obtaining viable DNA for analysis. In Pacific salmon Oncorhynchus spp., carcasses represent a feasible alternative for obtaining this tissue. However, the relative speed with which a salmon carcass decomposes can affect the quality of the extracted DNA. We extracted DNA from three different tissues (anal fin, operculum, and scales) obtained from carcasses of Chinook salmon O. tshawytscha at three different levels of decomposition (slight, moderate, and extensive). Freshly euthanized fish were included as a control. Extraction of DNA was accomplished using two common methods: the Chelex method and the Qiagen DNeasy spin column method. For each extracted sample, polymerase chain reaction (PCR) was used to amplify one small microsatellite locus (170–375 base pairs [bp]), one large nuclear locus (971 bp), and one large mitochondrial locus (1,300 bp). Results suggest that DNA suitable for PCR amplification at all three loci can be readily obtained from carcasses with slight decay. Qiagen spin columns appeared to provide the best extraction method, and fin clips were the optimal tissue type. Qiagen spin columns were the only extraction method that yielded DNA suitable for PCR from carcasses with moderate to extreme decay, although positive results were less reliable. Chelex extractions proved effective for amplifying small microsatellite loci from fin and scale samples but only those from carcasses with slight decay. With further optimization of techniques, we believe salmon carcasses can be used as a suitable source of tissue for DNA extraction and subsequent study in a conservation genetics framework.
The Effects of Violating Hardy–Weinberg Equilibrium Assumptions on a Cluster-based Population Mixture Analysis of Steelhead Populations in Southeast Alaska
Authors: Masuda Michele , Thrower Frank , Nichols Krista M.
Published: February 2009

Clustering methods for population mixture analysis assign individuals probabilistically to populations based on their multilocus genotype data. An assumption of the methods is that loci satisfy Hardy–Weinberg equilibrium (HWE) conditions within populations. We observed that violating this assumption by including loci measured as deviating from HWE in baseline samples for the mixture analysis at times introduced extra structure into the mixture sample, leading to biased composition estimates and overestimation of the number of populations. Provided that samples from at least some contributing populations are available and that baseline samples can safely be assumed to come from single populations, then a conservative approach to mixture analysis would be to include only those characters that conform to HWE in the baseline samples, but this approach could result in a loss of resolving power. To address this problem, we outlined an ad hoc method of selecting loci for their use in mixture analysis based on individual analyses of baseline samples. A subset of loci is selected for mixture analysis based on whether the loci contribute additional structure in the baseline populations, assuming that (1) baseline samples come from single populations and (2) any subpopulation structure resulting from the inclusion of loci measured as deviating from HWE is artifactual. Given that the final set may include only a few loci, the method would be most useful for small problems. We demonstrated the method on two sets of microsatellite loci (10 and 17 loci) genotyped in steelhead Oncorhynchus mykiss sampled at Sashin Creek in southeast Alaska. The method for selecting loci for mixture analysis generally reduced bias in and improved the precision of composition estimates and reduced the overestimation of the number of populations.
Contractor perspective of the new Irish public works contracts
Authors: Fogarty H.
Published: February 2009

Traditionally in Ireland the forms of contract used for government-funded projects were those published by either the Institution of Engineers of Ireland or the Royal Institute of the Architects of Ireland. They were based on the Institution of Civil Engineers and Joint Contracts Tribunal standard forms with minor changes to reflect local conditions. In 2007 the Irish government introduced a suite of bespoke contract forms for both employer-designed and contractor-designed projects. Although officially entitled ‘public works contracts’ they are colloquially known as the GCCC contracts after the Government Construction Contracts Committee, the body within the Irish Department of Finance responsible for drafting and introducing them. The new forms are fixed-price lump-sum contracts with considerably more construction risk transferred to contractors than under the previous forms. The forms are now mandatory for all new building and civil engineering infrastructural projects and many contractors have complained that some of the risks transferred are not only inappropriate but are incapable of assessment at tender stage. The paper sets out the history of the development of the new forms and provides an overview of the more contentious provisions.
Dispute boards on major infrastructure projects
Authors: Chapman P. H. J.
Published: February 2009

Prevention is better than cure. Using dispute boards on major infrastructure projects has been shown to reduce significantly the number of issues that become full-blown disputes and thereby involve the parties in time-consuming and costly arbitration and/or litigation. In this paper the author, a past-president of the Dispute Resolution Board Foundation and a leading exponent of dispute boards, reviews the history, purpose and proven benefits of dispute boards in the avoidance and early evaluation (adjudication) of disputes within the construction industry. The paper emphasises the importance of good job–site communication and how a proactive dispute board, particularly on international contracts, can positively influence on-site relationships and bring major project management benefits to the construction process. The appointment of dispute boards, the terms of engagement and best-practice procedures are discussed. The article reveals the remarkably successful dispute resolution figures of 98‥ when dispute boards are used in addition to the hidden benefits of dispute avoidance.
Landscape heterogeneity, soil climate, and carbon exchange in a boreal black spruce forest
Authors: Dunn Allison L. , Wofsy Steven C. , Bright Alframv H.
Published: February 2009

We measured soil climate and the turbulent fluxes of CO2, H2O, heat, and momentum on short towers (2 m) in a 160‐yr‐old boreal black spruce forest in Manitoba, Canada. Two distinct land cover types were studied: a Sphagnum‐dominated wetland, and a feathermoss (Pleurozium and Hylocomium)‐dominated upland, both lying within the footprint of a 30‐m tower, which has measured whole‐forest carbon exchange since 1994. Peak summertime uptake of CO2 was higher in the wetland than for the forest as a whole due to the influence of deciduous shrubs. Soil respiration rates in the wetland were approximately three times larger than in upland soils, and 30% greater than the mean of the whole forest, reflecting decomposition of soil organic matter. Soil respiration rates in the wetland were regulated by soil temperature, which was in turn influenced by water table depth through effects on soil heat capacity and conductivity. Warmer soil temperatures and deeper water tables favored increased heterotrophic respiration. Wetland drainage was limited by frost during the first half of the growing season, leading to high, perched water tables, cool soil temperatures, and much lower respiration rates than observed later in the growing season. Whole‐forest evapotranspiration increased as water tables dropped, suggesting that photosynthesis in this forest was rarely subject to water stress. Our data indicate positive feedback between soil temperature, seasonal thawing, heterotrophic respiration, and evapotranspiration. As a result, climate warming could cause covariant changes in soil temperature and water table depths that may stimulate photosynthesis and strongly promote efflux of CO2 from peat soils in boreal wetlands.
Can conservation biologists rely on established community structure rules to manage novel systems? … Not in salt marshes
Authors: Fariña JoséM. , Silliman Brian R. , Bertness Mark D.
Published: February 2009

We experimentally examined plant zonation in a previously unstudied Chilean salt marsh system to test the generality of mechanisms generating zonation of plants across intertidal stress gradients. Vertical zonation in this system is striking. The low‐lying clonal succulent, Sarcocornia fruticosa, dominates the daily flooded low marsh, while intermediate elevations are dominated by the much taller Spartina densiflora. Irregularly flooded higher elevations are dominated by Schoenoplectus californicus, with the small forb, Selliera radicans, found associated with Schoenoplectus at its base. Transplant studies of all four species into each zone both with and without competition revealed the mechanisms driving these striking patterns in plant segregation.

In the regularly flooded low marsh, Sarcocornia and Spartina grow in the zone that they normally dominate and are displaced when reciprocally transplanted between zones with neighbors, but without neighbors they grow well in each other's zone. Thus, interspecific competition alone generates low marsh zonation as in some mediterranean marshes, but differently than most of the Californian marshes where physical stress is the dominant factor. In contrast, mechanisms generating high marsh patterns are similar to New England marshes. Schoenoplectus dies when transplanted to lower elevations with or without neighbors and thus is limited from the low marsh by physical stress, while Selliera grows best associated with Schoenoplectus, which shades and ameliorates potentially limiting desiccation stress.

These results reveal that mechanisms driving community organization across environmental stress gradients, while generally similar among systems, cannot be directly extrapolated to unstudied systems. This finding has important implications for ecosystem conservation because it suggests that the mechanistic understanding of pattern generation necessary to manage and restore specific communities in novel habitats cannot rely exclusively on results from similar systems, and it identifies a critical role for experimental ecology in the management and conservation of natural systems and the services they provide.