bluuebunny/crossref_metadata_2025 huggingface dataset:
Migrants in Neotropical bird communities: an assessment of the breeding currency hypothesis
Authors: JOHNSON MATTHEW D. , SHERRY THOMAS W. , STRONG ALLAN M. , MEDORI AMANDA
Published: March 2005

Explanations for the integration of migratory and non‐migratory (resident) birds in the Neotropics have been complicated by the paradox that arthropod abundances are low when bird abundances reach their annual peak. The breeding currency hypothesis offers an explanation for this paradox by postulating that resident birds are limited in the breeding season by the availability of large arthropods suitable for reproduction, whereas the carrying capacity of all birds in the non‐breeding season is limited by the availability of arthropods suitable for self‐maintenance of adults.

Field data from Jamaica supported this hypothesis. Among 19 sites, the ratio of migrant to resident bird abundance was correlated negatively with the ratio of large arthropod biomass in the breeding season to total arthropod biomass in the non‐breeding season.

However, after controlling for effects of arthropod seasonality, migrant to resident bird abundance ratios were higher in human‐disturbed than undisturbed sites.

Other factors may interact with the availability of food for nestlings to limit the populations of resident birds below carrying capacities set by non‐breeding season arthropod abundance, thereby creating a set of resources available to non‐breeding migrants.
A new method to measure the polymerization shrinkage kinetics of light cured composites
Authors: LEE I.B. , CHO B.H. , SON H.H. , UM C.M.
Published: March 2005

summary  This study was undertaken to develop a new measurement method to determine the initial dynamic volumetric shrinkage of composite resins during polymerization, and to investigate the effect of curing light intensity on the polymerization shrinkage kinetics. The instrument was basically an electromagnetic balance that was constructed with a force transducer using a position sensitive photo detector (PSPD) and a negative feedback servo amplifier. The volumetric change of composites during polymerization was detected continuously as a buoyancy change in distilled water by means of the Archimedes’ principle. Using this new instrument, the dynamic patterns of the polymerization shrinkage of seven commercial composite resins were measured. The polymerization shrinkage of the composites was 1·92∼4·05 volume %. The shrinkage of a packable composite was the lowest, and that of a flowable composite was the highest. The maximum rate of polymerization shrinkage increased with increasing light intensity but the peak shrinkage rate time decreased with increasing light intensity. A strong positive relationship was observed between the square root of the light intensity and the maximum shrinkage rate. The shrinkage rate per unit time, dVol%/dt, showed that the instrument can be a valuable research method for investigating the polymerization reaction kinetics. This new shrinkage‐measuring instrument has some advantages that it was insensitive to temperature changes and could measure the dynamic volumetric shrinkage in real time without complicated processes. Therefore, it can be used to characterize the shrinkage kinetics in a wide range of commercial and experimental visible‐light‐cure materials in relation to their composition and chemistry.
Use of mental health and primary care services by caregivers of patients with bipolar disorder: a preliminary study
Authors: Perlick Deborah A , Hohenstein Jill M , Clarkin John F , Kaczynski Richard , Rosenheck Robert A
Published: March 2005

Objectives:  Caring for a relative with schizophrenia or dementia has been associated with reports of caregiver burden, symptoms of anxiety, depression, poor self‐rated health, and elevated health service use; however, comparable data for caregivers of relatives with bipolar disorder are lacking. This study reports preliminary data on the health, psychological distress and health service use of caregivers of patients with bipolar disorder. It additionally evaluates the relationship of the level of burden caregivers report experiencing to their use of health services, controlling for level of psychological distress and health status.

Methods:  Subjects were primary caregivers of 264 patients with Research Diagnostic Criteria‐diagnosed bipolar disorder and their bipolar relatives. Caregiver mental health and primary care service use were assessed retrospectively for the 7‐month period prior to inpatient or outpatient admission of the bipolar patient. Caregiver depression, anxiety, medical conditions and patient symptomatology were assessed as well.

Results:  Hierarchical logistic regression analysis demonstrated that caregiver burden significantly increased the likelihood of mental health service use (OR = 13.53, p < 0.001) even after controlling for caregiver psychological distress and medical conditions, while anxiety and depression level, but not burden, significantly increased the likelihood of primary care service use, controlling for other variables (OR = 1.72, p = 0.02).

Conclusions:  Burdens experienced by family caregivers appear to increase use of health services, and presumably cost, and may be reduced by psychosocial intervention.
Quality of life and its correlates in patients with dual diagnosis of bipolar affective disorder and substance dependence
Authors: Singh Jaspreet , Mattoo Surendra K , Sharan Pratap , Basu Debasish
Published: March 2005

Objectives:  To compare the quality of life (QOL) of patients having dual diagnosis of bipolar affective disorder and substance dependence with those having either diagnosis alone and with healthy controls.

Methods:  Cross‐sectional assessment of the four groups of subjects was made. Euthymic bipolar patients and those substance dependent patients not in active withdrawal or intoxication were included. QOL assessment was made with the World Health Organization (WHO)‐QOL – Bref Hindi version.

Results:  Total QOL score and scores on all the four domains of WHO‐QOL‐Bref were significantly lower for the dual‐diagnosis (DD) patients when compared with all the other groups. Significant negative correlations were found between (i) the number of days the drug was consumed and the score on the ‘general well‐being’ items of WHO‐QOL‐Bref (r = −0.31, p < 0.05); and (ii) between severity of alcohol dependence and WHO‐QOL total score (r = −0.44, p < 0.01) as well as its ‘psychological’ domain (r = −0.52, p < 0.05).

Conclusions:  The study indicates that bipolar DD patients experience a lower QOL when compared with the other groups studied. Their QOL is affected by the severity of alcohol dependence.
Women are not the same as men: specific clinical issues for female patients with bipolar disorder
Authors: Curtis Vivienne
Published: March 2005

Abstract:  Women are not the same as men. While this observation can be considered to subjectively manifest in many different ways, objectively a greater tendency for bipolar II disorder, depressive symptoms, a rapid cycling course, and the consequences of being of child‐rearing age can all represent additional challenges for female patients. Despite much recent interest in improving the management of patients with bipolar disorder, relatively little guidance exists relating to female‐biased gender‐specific issues. This review article will explore how female gender can influence bipolar disorder and its treatment and will focus on epidemiologic differences, the relevance to clinical presentation of events unique to women (particularly contraception, pregnancy, and lactation), and the importance of considering gender when making decisions about the pharmacological management of mood. All female patients should receive counseling regarding family planning and sexually transmitted diseases, as well as the risks of and treatment options during pregnancy and postpartum. Wherever possible, treatment choices should be made in a partnership between patient and clinician.
Number‐word sequence skill and arithmetic performance
Authors: JOHANSSON BO S.
Published: March 2005

In two studies, the role of the number‐word sequence skill for arithmetic performance was investigated. In the first, children between 4 and 8 years of age were asked to count forward and backward on the number‐word sequence and to solve arithmetic problems followed by post‐solution interviews about solution procedures. The results demonstrated that the number‐word sequence skill predicted both number of problems solved and strategy to solve the problems. In Study 2 it was found that solving doubles (e.g., 2 + 2 = ?) problems served as a link between the number‐word sequence skill and the number of arithmetic problems solved. The findings suggest that counting on the number‐word sequence may be an early solution procedure and that, with increasing counting skill, the child may detect regularities in the number‐word sequence that can be used to form new and more accurate strategies for solving arithmetic problems.
A GIS‐Based Approach for Delineating Market Areas for Park and Ride Facilities
Authors: Farhan Bilal , Murray Alan T.
Published: March 2005

Park‐and‐ride services are an integral component of many public transit systems in the United States. A necessary step when analyzing and planning for such services is to delineate catchment areas for park‐and‐ride facilities. Previous approaches for delineating catchment/market areas are either problematic or have unrealistic data requirements. This paper develops a Geographic Information System (GIS)‐based approach for delineating market areas. The detailed approach simultaneously accounts for park‐and‐ride facility accessibility and user travel direction. It is shown that the developed approach performs better than existing approaches. Further, this paper provides a detailed and formal description of these approaches, which should facilitate interpretation and implementation in a GIS environment.
How Far Is Too Far? – A Statistical Approach to Context‐contingent Proximity Modeling
Authors: Yao Xiaobai , Thill Jean‐Claude
Published: March 2005

Proximity is a fundamental concept in any comprehensive ontology of space (Worboys 2001). The provision of a context‐contingent translation mechanism between linguistic proximity measures (e.g. “near”, “far”) and metric distance measures is an important topic in current GIS research. After a discussion of context factors that mediate the relationship between linguistic and metric distance measures, we present a statistical approach, Ordered Logit Regression, to the context‐contingent proximity modeling. The approach can predict proximity given the corresponding metric distance and context variables. An empirical case study with human subjects is carried out using this statistical approach. Interpretation and predictive accuracy of the empirical case study are discussed.
GIS Tools for Freshwater Biodiversity Conservation Planning
Authors: FitzHugh Thomas W.
Published: March 2005

The Nature Conservancy (TNC) has developed a set of customized GIS tools to help ensure that freshwater biodiversity is adequately incorporated into its regional conservation planning efforts. The tools generate GIS data and attributes that support a regional‐scale classification of freshwater systems and analysis of the potential integrity of these same systems. They have been implemented by TNC in more than 30 ecoregions across the U.S., and work is expanding to include other parts of the Americas. The tools are now in their second iteration. While the first version of the tools worked only with the RF3 hydrography dataset available in the U.S., the second version is more flexible and will function with a variety of datasets. Future improvements in the tools could include an improved interface and improved algorithms to reduce data pre‐processing needs. The GIS tools, documentation, and data from completed ecoregions are now publicly available on the Internet.
Book Reviews
Authors: Dennis Samuel F. , Albrecht Jochen
Published: March 2005

Books reviewed:

MARSHA ALIBRANDI, GIS in the Classroom: Using Geographic Information Systems in Social Studies and Environmental Science

JO WOOD, Java Programming for Spatial Sciences
American Society of Diagnostic and Interventional Nephrology Section Editor: Stephen Ash: Does Catheter Insertion by Nephrologists Improve Peritoneal Dialysis Utilization? A Multicenter Analysis
Authors: Asif Arif , Pflederer Timothy A. , Vieira Cristovao F. , Diego Jorge , Roth David , Agarwal Anil
Published: March 2005

In contrast to hemodialysis (HD), peritoneal dialysis (PD) remains an underutilized form of renal replacement therapy in the United States. Although a variety of factors have been deemed responsible, timely insertion of a PD catheter may also be a contributory factor. We conducted a multicenter analysis to examine whether the establishment of a program for PD catheter insertion by nephrologists has a positive impact on the growth in the number of patients using PD. Data for catheter insertion performed by nephrologists were collected from three centers. Any change in the prevalent PD population at each respective center was compared to the number of PD patients during the period having the traditional surgical approach. Nephrologists at the three centers used the peritoneoscopic technique and performed catheter insertion under local anesthesia. In center 1, the PD population remained stable at between 38 and 45 patients (approximately 16% of the total end‐stage renal disease [ESRD] population) from 1993 to 2001. Nephrologists initiated a program for PD catheter insertion in 2001. The number of PD patients has increased to 101 (32% of the ESRD population). In center 2, the PD population remained stable at between 70 and 78 patients (approximately 17%) between 1988 and 1990. Catheter insertion by interventional nephrologists began in 1991. The number of PD patients has increased to 125 (22%). In center 3, the PD population remained at 20–30 patients (approximately 18%) between 1988 and 1991. Catheter placement by nephrologists was initiated in 1991. The number of PD patients increased to 97 (27%). Catheter insertion by interventional nephrologists was suspended in 2001. The number of PD patients has gradually declined to 25 (6%). This study suggests that catheter insertion by the nephrologist can have a positive impact on the utilization of PD.
PSYCHOSOCIAL FACTORS IN PATIENTS WITH CHRONIC KIDNEY DISEASE: Palliative Care in End‐Stage Renal Disease: Focus on Advance Care Planning, Hospice Referral, and Bereavement
Authors: Holley Jean L.
Published: March 2005

The components of palliative care in end‐stage renal disease (ESRD) include pain and symptom management, advance care planning, psychosocial and spiritual support, and ethical issues in dialysis. End‐of‐life care is not synonymous with, but rather a subset of palliative care. Advance care planning occurs within the patient‐family relationship and is a dynamic process that prepares for death, strengthens interpersonal relationships, and allows a patient to achieve control over his or her life. It is incumbent upon dialysis care providers to include advance care planning in overall care plans for their patients. Factors contributing to the failure of advance care planning in ESRD patients will be discussed, as will hospice and ESRD, and opportunities for bereavement programs.
PSYCHOSOCIAL FACTORS IN PATIENTS WITH CHRONIC KIDNEY DISEASE: The Identification and Treatment of Depression in Patients Maintained on Dialysis
Authors: Wuerth Diane , Finkelstein Susan H. , Finkelstein Fredric O.
Published: March 2005

The high incidence of depression in end‐stage renal disease (ESRD) patients is well documented. Our group and others have estimated that 20–30% of ESRD patients experience major depression. Several recent studies have emphasized the relationship between depressive symptoms and mortality and morbidity in both hemodialysis (HD) and peritoneal dialysis (PD) patients. We screened 380 PD patients for depression using the Beck Depression Inventory (BDI). The mean patient age was 59.9 ± 14.1 (SD) years, 55% were Caucasian, 51% were male, and 39% had diabetes. The mean BDI score was 12.1 ± 7.7; 49% had a score of 11 or greater. Fifty‐five percent refused further assessment to confirm the diagnosis of major depression, while 45% of patients eligible for treatment agreed to further assessment. Their mean BDI was 18.8 ± 6.2. Eighty‐four percent were diagnosed with major depression on direct interviews and offered pharmacologic treatment, 16% did not meet the criteria for a diagnosis of depression, and 50% successfully completed 12 weeks of pharmacologic treatment. The BDI score of these patients at the start of treatment was 17.4 ± 6.6, and at completion of treatment it was 8.4 ± 3.0. Thirty‐eight percent of treatment failures were in those who were also diagnosed with a DSM‐IV personality disorder. Major depression is common in PD patients, and is potentially treatable with pharmacologic therapy. However, there are major problems providing a depression assessment and treatment program to such patients. Problems include refusal to complete depression assessment and patients with axis 2 personality disorders who have difficulty complying with treatment. Although depression treatment can improve depressive symptoms, it is unclear whether such therapy will improve medical outcomes.
PSYCHOSOCIAL FACTORS IN PATIENTS WITH CHRONIC KIDNEY DISEASE: Life After Transplantation: New Transitions in Quality of Life and Psychological Distress
Authors: Muehrer Rebecca J. , Becker Bryan N.
Published: March 2005

Individuals with kidney failure often elect to undergo kidney transplantation because they believe that they will be more active and return a sense of normality to their lives with a functioning transplant. Therefore it is important to assess whether these objectives are being met. To do so, we can examine health‐related quality of life (HRQOL) in transplant recipients. A number of tools have been used for this purpose, including general HRQOL instruments such as the 36‐item short‐form health survey (SF‐36) and transplant‐specific surveys such as the Kidney Transplant Questionnaire. In general, HRQOL assessments improve with transplantation in functional and physical domains. However, many factors actually influence HRQOL in a negative way, including comorbid conditions, kidney function per se, rejection episodes and hospitalizations, employment status, and adverse effects of medications. Perceived physical appearance, issues related to sexuality, stress, anxiety, and even guilt complicate the emotional and psychological landscape after transplantation. This constellation of factors may be predictive of posttransplant life events, such as resumption of employment. Posttransplant HRQOL may be exceedingly important in understanding the issues related to adherence with treatment regimens, especially in the pediatric and adolescent transplant populations. HRQOL is now established as an important issue after transplantation. Nonetheless, shortcomings still exist in our ability to address HRQOL after transplantation. In particular, more study of patient‐centered interventions is needed. The use of standardized methodologies for patient assessment could improve our ability to identify if such patient‐centered interventions actually succeed across populations, and help us further address the panoply of factors encompassed within posttransplant HRQOL.
Sonochemical Preparation and Properties of Pt–3Y‐TZP Nano‐Composites
Authors: Vasylkiv Oleg , Sakka Yoshio , Maeda Yasuaki , Skorokhod Valeriy V.
Published: March 2005

A uniformly aggregated 3 mol% yttria‐stabilized tetragonal zirconia nano‐powder (3Y‐TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano‐engineering of Pt–3Y‐TZP composite aggregates was studied. The as‐synthesized Pt nano‐particles (∼2 nm) were impregnated into zirconia nano‐aggregates (20–45 nm). The morphology manipulation technique allowed production of the composite zirconia‐based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low‐temperature (1150°C) sintering, we prepared the Pt‐zirconia (0.5–1.5 wt% of platinum) nano‐composites with average 3Y‐TZP grain sizes of 120 nm, and with the platinum grains size in the range of 20–60 nm. The catalytic properties of composite Pt–3Y‐TZP nano‐composites were studied and described.
The Influence of Water on the Fracture of Magnesium Aluminate (MgAl2O4) Spinel
Authors: Van Der Laag N. J. , Van Dijk A. J. M. , Lousberg N. , De With G. , Dortmans L. J. M. G.
Published: March 2005

The influence of water on the fracture of magnesium aluminate (MgAl2O4) ceramics and spinel single crystals is investigated in order to determine whether adsorption plays an important role during subcritical crack growth as it does for MnZn ferrites, a compound with the same spinel structure. The fracture toughness of porous and dense polycrystalline ceramic and single crystal specimens are determined using a single edge notched beam setup at different crosshead velocities and humidities. Furthermore, in order to investigate whether a preferred plane of fracture is present, electron backscattered diffraction (EBSD) has been performed. It is found that the fracture toughness decreases with increasing humidity for dense ceramics, indicating that adsorption plays an important role as it does for MnZn ferrites. However, porous ceramics only show a sharp decrease between 0% and 2–10% relative humidity (RH) and hardly decreases onwards. This implies that the pores inhibit in some way the effect of adsorption during fracture. The exact mechanism remains unclear. EBSD measurements indicated that a preferred plane is absent. Therefore, the fracture of spinel single crystal along the (100) and (111) planes was chosen for further detailed investigation. It is revealed that between 2% and 40% RH both planes show a reduction in fracture surface energy of ∼46%. Using reported computer simulations results, it can be concluded that the surfaces are partially hydrated when being fractured.
Microwave Dielectric Properties of (1−x)(Na1/2Nd1/2)TiO3−xLa(Mg1/2Ti1/2)O3 via Ordering and Far IR Reflectivity Spectra
Authors: Kim Jae Beom , Yoon Ki Hyun , Cho Yong S. , Kim Woo Sup , Kim Eung Soo
Published: March 2005

Microwave dielectric properties of (1−x)(Na1/2Nd1/2)TiO3(NNT)−xLa(Mg1/2Ti1/2)O3(LMT) system have been investigated with focus on structural ordering and far IR reflectivity spectra. A single perovskite phase was found to exist with various superlattice reflections over the entire compositional range. 1:1 ordering observed in the (111) reflection of X‐ray diffraction patterns was found to progress significantly in the specimens above x=0.8. The ordering characteristics that presumably related to B‐site Mg/Ti ordering were assumed to affect favorably the quality factor at microwave frequencies. The increase of the quality factor also could be explained in terms of the decrease of lattice anharmonicity with LMT by analysis of far IR reflectivity spectra. As expected from the values of pure NNT and LMT, the dielectric constant and the temperature coefficient of frequency tended to gradually decrease with increasing LMT content.
Hydroxylated Carboxylic Acid Monomers as Stabilizing Agents for Yttria–Alumina Aqueous Suspensions
Authors: Yasrebi Mehrdad , Van Ginhoven Renee , Kemp William W. , Schmidt Brenda J. , Sturgis David H.
Published: March 2005

The effect of hydroxylated benzoic acid monomers on the colloidal stability of yttria–alumina binary aqueous suspensions is examined. The above property is also compared with those of citric acid, and polymethacrylic acid. It is observed that among the acids examined, only 2, 3‐dihydroxybenzoic acid effectively prevents a change in the viscosity of yttria–alumina binary aqueous suspensions versus time. This phenomenon is attributed to the lower tendency of 2, 3‐dihydroxybenzoic acid to adsorb dissolving yttrium ions from solution.
Domain Structures in Perovskite‐Type Lanthanum Magnesium Titanate Ceramics
Authors: Kipkoech Erick Rop , Azough Feridoon , Freer Robert
Published: March 2005

La(Mg1/2Ti1/2)O3 ceramics were prepared using a conventional solid‐state reaction route. X‐ray diffraction analysis revealed that La(Mg1/2Ti1/2)O3 possesses a distorted perovskite structure consisting of both in‐phase and anti‐phase tilting accompanied by anti‐parallel shifting of La3+ cation. Superlattice reflections, indicative of 1:1‐type ordering of Mg2+ and Ti4+ cations in the octahedral sites, were observed. The crystal symmetry was deduced to be monoclinic with P21/n space group (No. 14). Transmission electron microscopy analysis revealed two types of twin domains, classified according to the symmetry elements relating adjacent domains. Twin domains with specific orientations, related by mirror operations along {112} and (110) planes, were identified. La(Mg1/2Ti1/2)O3 exhibited a high density of dislocations that interact with the twin boundaries resulting in incoherent twin interfaces. In addition, two morphologically distinct anti‐phase domains were observed resulting from (i) off‐center displacement of the La3+ cations, and (ii) 1:1 ordering of the B‐site sublattice.
α‐Latrotoxin increases spontaneous and depolarization‐evoked exocytosis from pancreatic islet β‐cells
Authors: Silva Amelia M. , Liu‐Gentry June , Dickey Adam S. , Barnett David W. , Misler Stanley
Published: March 2005

α‐Latrotoxin (α‐LT), a potent excitatory neurotoxin, increases spontaneous, as well as action potential‐evoked, quantal release at nerve terminals and increases hormone release from excitable endocrine cells. We have investigated the effects of α‐LT on single human, mouse and canine β‐cells. In isolated and combined measurements, α‐LT, at nanomolar concentrations, induces: (i) rises in cytosolic Ca2+, into the micromolar range, that are dependent on extracellular Ca2+; (ii) large conductance non‐selective cation channels; and (iii) Ca2+‐dependent insulin granule exocytosis, measured as increases in membrane capacitance and quantal release of preloaded serotonin. Furthermore, at picomolar concentrations, α‐LT potentiates depolarization‐induced exocytosis often without evidence of inducing channel activity or increasing cytosolic Ca2+. These results strongly support the hypothesis that α‐LT, after binding to specific receptors, has at least two complementary modes of action on excitable cells. (i) α‐LT inserts into the plasma membrane to form Ca2+ permeable channels and promote Ca2+ entry thereby triggering Ca2+‐dependent exocytosis in unstimulated cells. (ii) At lower concentrations, where its channel forming activity is hardly evident, α‐LT augments depolarization‐evoked exocytosis probably by second messenger‐induced enhancement of the efficiency of the vesicle recruitment or vesicle fusion machinery. We suggest that both modes of action enhance exocytosis from a newly described highly Ca2+‐sensitive pool of insulin granules activated by global cytosolic Ca2+ concentrations in the range of ∼1 μm.
Autoregulation of the cerebral circulation during sleep in newborn lambs
Authors: Grant Daniel A. , Franzini Carlo , Wild Jennene , Eede Kellie J. , Walker Adrian M.
Published: March 2005

Autoregulation is a vital protective mechanism that maintains stable cerebral blood flow as cerebral perfusion pressure changes. We contrasted cerebral autoregulation across sleep–wake states, as little is known about its effectiveness during sleep. Newborn lambs (n= 9) were instrumented to measure cerebral blood flow (flow probe on the superior sagittal sinus) and cerebral perfusion pressure, then studied during active sleep (AS), quiet sleep (QS) and quiet wakefulness (QW). We generated cerebral autoregulation curves by inflating an occluder cuff around the brachiocephalic artery thereby lowering cerebral perfusion pressure. Baseline cerebral blood flow was higher (P < 0.05) and cerebral vascular resistance lower (P < 0.05) in AS than in QW (76 ± 8% and 133 ± 15%, respectively, of the AS value, mean ±s.d.) and in QS (66 ± 11% and 158 ± 30%). The autoregulation curve in AS differed from that in QS and QW in three key respects: firstly, the plateau was elevated relative to QS and QW (P < 0.05); secondly, the lower limit of the curve (breakpoint) was higher (P < 0.05) in AS (50 mmHg) than QS (45 mmHg); and thirdly, the slope of the descending limb below the breakpoint was greater (P < 0.05) in AS than QS (56% of AS) or QW (56% of AS). Although autoregulation functions in AS, the higher breakpoint and greater slope of the descending limb may place the brain at risk for vascular compromise should hypotension occur.
Hyperthermia increases sensitivity of pulmonary C‐fibre afferents in rats
Authors: Ruan Ting , Gu Qihai , Kou Yu Ru , Lee Lu‐Yuan
Published: March 2005

This study was carried out to investigate whether an increase in tissue temperature alters the excitability of vagal pulmonary C‐fibres. Single‐unit afferent activities of 88 C‐fibres were recorded in anaesthetized and artificially ventilated rats when the intrathoracic temperature (Tit) was maintained at three different levels by isolated perfusion of the thoracic chamber with saline: control (C: ∼36°C), medium (M: ∼38.5°C) and high (H: ∼41°C), each for 3 min with 30 min recovery. Our results showed: (1) The baseline fibre activity (FA) of pulmonary C‐fibres did not change significantly at M, but increased drastically (>5‐fold) at H. (2) The C‐fibre response to right‐atrial injection of capsaicin (0.5 μg kg−1) was markedly elevated at H (ΔFA = 5.94 ± 1.65 impulses s−1 at C and 13.13 ± 2.98 impulses s−1 at H; P < 0.05), but not at M. Similar increases in the C‐fibre responses to other chemical stimulants (e.g. adenosine, etc.) were found at H; all the enhanced responses returned to control in 30 min. (3) The C‐fibre response to lung inflation was also significantly potentiated at H. In sharp contrast, there was no detectable change in either the baseline activity or the responses to lung inflation and deflation in 10 rapidly adapting pulmonary receptors and 10 slowly adapting pulmonary receptors at either M or H. (4) The enhanced C‐fibre sensitivity was not altered by pretreatment with indomethacin or capsazepine, a selective antagonist of the transient receptor potential vanilloid type 1 (TRPV1) receptor, but was significantly attenuated by ruthenium red that is known to be an effective blocker of all TRPV channels. (5) The response of pulmonary C‐fibres to a progressive increase in Tit in a ramp pattern further showed that baseline FA started to increase when Tit exceeded 39.2°C. In conclusion, a pronounced increase in the baseline activity and excitability of pulmonary C‐fibres is induced by intrathoracic hyperthermia, and this enhanced sensitivity probably involves activation of temperature‐sensitive ion channel(s), presumably one or more of the TRPV receptors, expressed on the C‐fibre endings.
Molecular Mechanisms for the Functionality of Lubricant Additives
Authors: Mosey Nicholas J. , Müser Martin H. , Woo Tom K.
Published: March 2005

Wear limits the life-span of many mechanical devices with moving parts. To reduce wear, lubricants are frequently enriched with additives, such as zinc phosphates, that form protective films on rubbing surfaces. Using first-principles molecular dynamics simulations of films derived from commercial additives, we unraveled the molecular origin of how antiwear films can form, function, and dissipate energy. These effects originate from pressure-induced changes in the coordination number of atoms acting as cross-linking agents to form chemically connected networks. The proposed mechanism explains a diverse body of experiments and promises to prove useful in the rational design of antiwear additives that operate on a wider range of surface materials, with reduced environmental side effects.
Sonogashira Cross-Coupling in the Synthesis of Acyclic Nucleoside Phosphonates: Preparation of 6-[(Phosphonomethoxy)alkynyl]- and 6-[(Phosphonomethoxy)alkyl]pyrimidines
Authors: Hocková Dana , Masojídková Milena , Holý Antonín
Published: March 2005

Several 6-[(phosphonomethoxy)alkyl]pyrimidines and 6-[(phosphonomethoxy)alkynyl]pyrimidines were prepared as saturated and unsaturated carba-analogues of antivirally active 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidine. As the key step of their synthesis the Sonogashira cross-coupling reaction was successfully applied. The replacement of the C-O moiety by the C-C bond resulted in the loss of biological activity.
Generalized instream habitat models
Authors: Lamouroux Nicolas , Jowett Ian G
Published: March 2005

Conventional instream habitat models (e.g., the physical habitat simulation system) predict the impact of regulation on the habitats of freshwater taxa. They link a hydraulic model with microhabitat-suitability models for taxa to predict habitat values at various discharge rates. Their use requires considerable field effort and experience. Recent analyses performed in France suggested that comparable results could be achieved using simplified hydraulic data. We tested this approach for 99 stream reaches and nine aquatic taxa in New Zealand. The resulting generalized habitat models predict habitat values similar to those predicted by conventional models from simplified hydraulic data (depthdischarge and widthdischarge relationships, average particle size, and mean annual discharge). As in France, within-reach changes in habitat values were linked to the specific discharge of reaches, while between-reach changes depended mainly on the Froude number at mean annual discharge. The generalized models perform well outside their calibration range. Models previously developed in France perform well in New Zealand. Such generalized models contribute to identifying the key hydraulic variables for freshwater taxa and should facilitate habitat studies worldwide.
Evidence for cumulative temperature as an initiating and terminating factor in downstream migratory behavior of Atlantic salmon (Salmo salar) smolts
Authors: Zydlewski Gayle Barbin , Haro Alex , McCormick Stephen D
Published: March 2005

Temperature control of Atlantic salmon (Salmo salar) smolt migration was tested using a novel technique allowing nearly continuous monitoring of behavior with complete control over environmental conditions. Parr and presmolts were implanted with passive integrated transponder tags, placed in simulated streams, and monitored for upstream and downstream movements. Beginning 18 April, temperature was increased 1 °C every third day (advanced), fourth day (ambient), and tenth day (delayed). Smolt downstream movements were initially low, peaked in mid-May, and subsequently declined under all conditions. Parr downstream movements were significantly lower than those of smolts in all treatments (0.8 ± 0.5 movement·day1 versus 26.5 ± 4.5 movements·day1, mean ± SE) and showed no increase. At delayed temperatures, smolts sustained downstream movements through July; those under ambient and advanced conditions ceased activity by mid-June. Initiation and termination of downstream movements occurred at significantly different temperatures but at the same number of degree-days in all treatments. Physiological changes associated with smolting (gill Na+,K+-ATPase activity and plasma thyroxine) were coincident with behavioral changes. This is the first evidence of a behavioral component to the smolt window. We found that temperature experience over time is more relevant to initiation and termination of downstream movement than a temperature threshold.
Stable carbon and nitrogen isotope analysis of Nephrops norvegicus / Merluccius merluccius fishing grounds in the Bay of Biscay (Northeast Atlantic)
Authors: Loc'h François Le , Hily Christian
Published: March 2005

The trophic structure of the benthic ecosystem of the Grande Vasière (Great Mud Bank), a heavily trawled area in the Bay of Biscay, is largely unknown. To better understand the biotic interactions between exploited species (mainly Norway lobster, Nephrops norvegicus, and European hake, Merluccius merluccius) and their competitors and prey, we applied a dual stable carbon (13C/12C) and nitrogen (15N/14N) isotope analysis to determine trophic levels and differences in the potential food sources of species in the benthic and demersal communities. Five main groups of species constitute the basis of the trophic structure. They are distributed in three main trophic levels: primary consumers; secondary consumers including N. norvegicus and juvenile M. merluccius; and top predators including adult M. merluccius (δ15N = 14.5). The large differences in δ13C values within the primary consumers attest to two different food components: a pelagic component composed of fresh sedimenting particulate organic matter, which mainly supplies supra- and epi-benthic suspension feeders, and zooplankton, and a benthic component, which mainly supplies deposit feeders. For the predators, the target species, and their competitors, diet changes during the life-span are reflected by differences in isotope values for the size classes.
A laboratory study of normally consolidated kaolin clay
Authors: Prashant Amit , Penumadu Dayakar
Published: March 2005

In recent years many researchers have attempted to address the need for a comprehensive understanding of the three-dimensional mechanical behavior of frictional materials. Advances in testing methods have added the capability of studying various aspects of generalized stressstrain behavior in a controlled environment. Strain-controlled true triaxial undrained tests on normally consolidated kaolin clay are performed in this study using a fully automated flexible boundary experimental setup with a real-time feedback control system. The influence of the intermediate principal stress and principal stress rotation on the stressstrainstrength and pore pressure behavior is investigated considering the occurrence of strain localization within the specimen. The strength behavior observed in this study of kaolin clay is used to evaluate existing failure criteria for cohesive soil. Comparative laboratory tests, such as the lubricated end triaxial test on a solid cylindrical kaolin specimen and combined axialtorsional tests on a hollow cylindrical kaolin specimen, were also performed to evaluate the corresponding mechanical behavior in different loading systems. Despite using identical techniques for specimen preparation and a similar consolidation stress state, the soil behavior obtained from the three types of tests showed observable variations, demonstrating the importance of specimen shape and loadingboundary conditions.Key words: normally consolidated clay, stress-strain behavior, pore pressure, anisotropy, testing methods.
Analysis of tunnels in shaly rock considering three-dimensional stress effects on swelling
Authors: Hawlader B C , Lo K Y , Moore I D
Published: March 2005

Underground structures in shales or shaly rocks endure time-dependent swelling effects. Laboratory test results show that the swelling of these shales is dependent on three-dimensional stresses; an external stress on a specimen in one principal direction reduces the swelling not only in that direction but also perpendicularly. The effectiveness of a time-dependent swelling model that considers the three-dimensional stress effect is presented in this paper. A finite element algorithm incorporating the new constitutive model is used for a numerical analysis. The finite element program is used to analyze two tunnels in southern Ontario: the Heart Lake storm sewer tunnel, and the Darlington cold-water intake tunnel. The predicted results agree well with the records of field performance of these tunnels. The comparison between present analyses and the existing closed-form solution shows that the existing solution overestimates the time-dependent swelling effects. The three-dimensional stress effects on swelling are not considered in the closed-form solutions and are the cause of this discrepancy. The pseudo-Poisson's effect is a key parameter for modelling the observed time-dependent swelling. The use of these solutions in design is discussed.Key words: time-dependent swelling, shale, modelling, three-dimensional stress effect, finite element method, tunnel.
Neural network based stochastic design charts for settlement prediction
Authors: Shahin M A , Jaksa M B , Maier H R
Published: March 2005

Traditional methods of settlement prediction of shallow foundations on granular soils are far from accurate and consistent. This can be attributed to the fact that the problem of estimating the settlement of shallow foundations on granular soils is very complex and not yet entirely understood. Recently, artificial neural networks (ANNs) have been shown to outperform the most commonly used traditional methods for predicting the settlement of shallow foundations on granular soils. However, despite the relative advantage of the ANN based approach, it does not take into account the uncertainty that may affect the magnitude of the predicted settlement. Artificial neural networks, like more traditional methods of settlement prediction, are based on deterministic approaches that ignore this uncertainty and thus provide single values of settlement with no indication of the level of risk associated with these values. An alternative stochastic approach is essential to provide more rational estimation of settlement. In this paper, the likely distribution of predicted settlements, given the uncertainties associated with settlement prediction, is obtained by combining Monte Carlo simulation with a deterministic ANN model. A set of stochastic design charts, which incorporate the uncertainty associated with the ANN method, is developed. The charts are considered to be useful in the sense that they enable the designer to make informed decisions regarding the level of risk associated with predicted settlements and consequently provide a more realistic indication of what the actual settlement might be.Key words: settlement prediction, shallow foundations, neural networks, Monte Carlo, stochastic simulation.
Genetic variation at early ages for several traits of interest for timber-production breeding ofJuglans regia
Authors: Díaz R , Fernández-López J
Published: March 2005

Several traits of common walnut (Juglans regia L.) were assessed during the first three growing seasons in a progeny test of 43 open-pollinated families at two sites in northwestern Spain. Variance components, heritabilities and correlations between traits were calculated for all characteristics measured. Significant differences were found among families with regard to growth, phenology, frost damage, number of apical branches, and Phytophthora cinnamomi Rands damage, but not for growth-habit traits (number of branches, stem form, and apical dominance). Heritabilities were moderate for total height (h2i≥ 0.32; h2f≥ 0.63) and late-spring frost damage (h2i = 0.29; h2f = 0.57), high for resistance to P. cinnamomi (h2i = 0.76; h2f = 0.85), and low for phenology (h2i = 0.15; h2f = 0.39 for bud burst, and h2i = 0.140.36; h2f= 0.440.70 for leaf fall) and root-collar diameter (h2i = 0.180.29; h2f = 0.410.58). High ageage correlations were found for growth and phenology traits during the first three growing seasons. Some interesting correlations were also found between several of the traits studied. The families whose buds burst the earliest had more late-spring frost damage and, consequently, more apical branches (i.e., branches near the apical bud). Furthermore, the greater the resistance to P. cinnamomi and frost damage, the taller the families.
Fire regime in a conservation reserve in Chihuahua, Mexico
Authors: Fulé Peter Z , Villanueva-Díaz José , Ramos-Gómez Mauro
Published: March 2005

Fire regime characteristics were reconstructed from fire-scarred trees in the Tutuaca reserve, a newly designated protected area in the Sierra Madre Occidental of western Chihuahua. The reserve was created to protect thick-billed parrot nesting habitat (large snags) and a relict forest of Chihuahua spruce (Picea chihuahuana Martínez). We collected fire-scarred samples from conifers (Pinus ayacahuite Ehrenb., Pinus durangensis Martínez, and Pseudotsuga menziesii (Mirb.) Franco) in three 25-ha sites arrayed at different watershed positions, from a low site adjacent to the spruce trees up to the watershed divide. Fire analysis periods began in 1702, 1704, or 1761 and continued through the final fire in 1955 (two sites) or 1995. All sites had frequent fire regimes (mean fire interval (MFI) 3.95.2 years; MFI for years in which 25% or more of the samples were scarred: 6.98.4 years). Almost all fires occurred before cambial growth began or early during the season of cambial growth. Fire years were significantly dry, and the years immediately preceding fire were significantly wet. After 1955, no further fires occurred at two of the three study sites, a pattern similar to that observed elsewhere in northern Mexico. The third site had fires in 1987 and 1995. The extended fire-free period in portions of the Tutuaca landscape may result in fuel accumulation and eventually in severe wildfire. For effective conservation of fire-susceptible habitat features, managers should seek to incorporate surface fire as a management tool.
Ophiostomatoid and basidiomycetous fungi associated with green, red, and grey lodgepole pines after mountain pine beetle (Dendroctonus ponderosae) infestation
Authors: Kim Jae-Jin , Allen Eric A , Humble Leland M , Breuil Colette
Published: March 2005

The mountain pine beetle (MPB) is a major concern for lodgepole pine (Pinus contorta var. latifolia Engelm.) forests in British Columbia, Canada. MPB and the ophiostomatoid staining fungi for which they serve as vector have a close, mutualistic relationship. In this work, we determined which fungi colonized MPB-killed standing trees with green, red, and grey crowns and quantified how rapidly the fungi stained and reduced the moisture content of sapwood. Green trees were mainly colonized by Ophiostoma clavigerum (Robinson-Jeffrey & Davidson) Harrington, Ophiostoma montium (Rumbold) von Arx, Ophiostoma nigrocarpum (Davidson) De Hoog, Ophiostoma minutum (Olchow. & Reid) Hausner, and unknown Leptographium species. In red and grey pines (2 and 3 years after the original MPB attack, respectively), the frequency of the original fungal colonizers decreased, and other sapstaining fungal species were encountered. Among basidiomycetous fungi, decay fungi were rarely present in green trees but were isolated more frequently in red and grey trees. The frequency and the type of decay fungi isolated varied between harvesting sites.
Fungal flora associated withIps typographus: frequency, virulence, and ability to stimulate the host defence reaction in relation to insect population levels
Authors: Sallé Aurélien , Monclus Romain , Yart Annie , Garcia Jacques , Romary Paul , Lieutier François
Published: March 2005

This study was aimed at determining the composition of Ips typographus L. (Coleoptera: Scolytidae) associated fungal flora in France, its virulence, and its ability to stimulate host defence reactions. The relationship between these parameters and the beetle population levels was also considered. The study was conducted in 2001, 2002, and 2003 in Norway spruce (Picea abies (L.) Karst.) stands, with different bark beetle damage levels. In each stand, the frequency of association between fungi and I. typographus was determined. The virulence of the most frequent species was assessed through mass inoculations on living spruce trees. The ability to stimulate the host defence reactions was estimated with low-density inoculations. The most frequent species, Ophiostoma bicolor Davids. & Wells, Ophiostoma piceaperdum Rumbold, and Ophiostoma tetropii Mathiesen, were all pathogenic. Ophiostoma piceaperdum also induced intense defence reaction zones, suggesting that it could play a role in I. typographus population establishment on living trees. However, significant correlations between fungal frequencies and damage of the current year were observed only with O. tetropii or O. bicolor, and no relationships between damage of the previous year and fungal frequencies were found. The effects of some fungal species on beetle population dynamics was suggested, but selection of species during epidemic condition was not confirmed.