bluuebunny/crossref_metadata_2025 huggingface dataset:
Argatroban for anticoagulation during cardiac surgery
Authors: Martin Monte E. , Kloecker Goetz H. , Laber Damian A.
Published: December 2006

Background: The aim of this study was to report our experience and review the published data on argatroban administration during adult cardiac surgery. Methods: The information on all reported cases of argatroban use in adults, during cardiac surgery was reviewed, including that of the patient described here. This analysis focused on patient characteristics, type of surgery, argatroban dosing schedule, monitoring of anticoagulation and outcomes. Results: Twenty‐one cases have been reported. Fifteen patients underwent off‐pump surgical procedures with the argatroban dose adjusted to maintain an activated clotting time (ACT) range between 200 and 300 s. Three intraoperative thrombi occurred in two patients when the ACT was <280 s. None had coagulopathy. Six cases reported the use of argatroban during on‐pump cardiac surgery dosed to keep the ACT >400 s. Intraoperative thrombotic complications were not reported in this group; however, one clot in the pump was noted after the procedure when the ACT was between 300 and 350 s. All six cases required larger volumes of perioperative blood products and three had severe coagulopathy. Of the 21 cases, seven had an indication for continued anticoagulation following surgery. Four cases did not report further use of argatroban after surgery. Three patients received argatroban after surgery without complications. Recommendations for how to use argatroban during cardiac surgery are proposed. Conclusions: Argatroban, with ACT monitoring, might be safely used for anticoagulation during cardiac surgery.
The timed‐pregnant baboon animal model can be used for determining the role of soluble vascular endothelial growth factor receptors 1 and 2 during development
Authors: Santolaya‐Forgas Joaquin , Edwin Samuel , Zeiter Katie , Pitt Adam , Pineles Beth , Tarca Adi L. , Espinoza Jimmy , Kusanovic Juan Pedro , Erez Offer , Wolf Roman , Romero Roberto
Published: December 2006

Background  During pregnancy, mechanisms that allow for regulation of continuous fetal and placental vasculogenesis with prevention of maternal neo‐vascularization remain elusive. The vascular endothelial growth factor (VEGF) biological system has a key role during vasculogenesis. The aims of this study were to validate a bioassay for soluble vascular endothelial growth factor receptors 1 and 2 (sVEGFR‐1 and sVEGFR‐2) in baboon plasma and to determine the maternal and fetal plasma concentration of these receptors at the end of the baboon pregnancy.

Methods  Maternal peripheral blood samples were obtained from eight baboons (Papio anubis) prior to elective cesarean section and from the umbilical cord after the fetuses were delivered. Spike and recovery experiments at various concentrations in pooled baboon maternal plasma were used to validate a human quantitative sandwich immunoassay for sVEGFR‐1 and ‐2. Concentrations of sVEGFR‐1 and ‐2 were then determined in maternal and fetal plasma samples.

Results  No significant correlations were observed between sVEGFR‐1 or ‐2 concentrations in maternal and fetal circulations. The concentration of sVEGFR‐1 was at least 30 times greater and that of sVEGFR‐2 approximately two times greater, in maternal than in cord plasma (both P < 0.01).

Conclusions  These findings suggest that baboons can be used to study the regulation of vasculogenesis during pregnancy.
Antiproliferative effects of melatonin on the growth of rat pituitary prolactin‐secreting tumor cells in vitro
Authors: Yang Quan‐Hui , Xu Jian‐Ning , Xu Rong‐Kun , Pang Shiu‐Fun
Published: December 2006

Abstract:  Earlier studies showed that melatonin reduced the growth of 17‐β‐estradiol (E2)‐induced rat pituitary prolactin‐secreting tumor (prolactinoma) in vivo. The mechanisms of melatonin's inhibitory action on the prolactin‐secreting tumor were further explored by investigating the in vitro effects of melatonin on the growth of pituitary prolactin‐secreting tumor cells. Primary cultured prolactinoma cells from E2‐induced rat pituitary prolactin‐secreting tumor were treated with 10−5, 10−4 or 10−3 m melatonin for 5 days. Apoptosis was evaluated using flow cytometry and the TdT‐mediated dUTP nick‐end labeling (TUNEL) method. In addition, cell viability was analyzed by (3,4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. It was found that incubation of prolactinoma cells with 10−5, 10−4 or 10−3 m melatonin for 5 days inhibited cell growth and increased cell apoptosis. Furthermore, melatonin increased caspase‐3 activity, Bax mRNA expression, and cytochrome c protein expression. Conversely, Bcl‐2 mRNA expression and mitochondrial membrane potential were inhibited by melatonin treatment. Our results further suggest that melatonin inhibits tumor growth by inducing apoptosis of rat pituitary prolactin‐secreting tumor directly via the damage of mitochondria.
The effect of myocardial infarction on the synthesis, concentration and receptor expression of endogenous melatonin
Authors: Sallinen Pirkko , Mänttäri Satu , Leskinen Hanna , Ilves Mika , Vakkuri Olli , Ruskoaho Heikki , Saarela Seppo
Published: December 2006

Abstract:  We examined the time course of changes in the synthesis and levels of endogenous melatonin and in the expression of MT1 and MT2 melatonin receptors 1 day, 2 and 4  wk after myocardial infarction (MI) in rats. MI was produced by ligation of the left anterior descending coronary artery. Transthoracic echocardiography was performed to characterize structural and functional changes after MI. mRNA levels were measured by real‐time quantitative reverse transcription‐polymerase chain reaction and proteins by Western blotting. One day after infarction, MI rats had 4.3 times (P < 0.001) higher pineal melatonin synthesis, than sham‐operated animals, which was associated with the increased concentration of melatonin in plasma (P < 0.001) and left ventricle (LV) (P = 0.01). The amount of MT1 receptor protein decreased significantly in MI LVs compared with control LVs 1 day after infarction (P < 0.01), followed by recovery during the next 2 wk. Furthermore, the expression of MT1 receptor mRNA of the MI LVs was elevated 2 wk after infarction (P < 0.01) compared with control LVs. The amount of MT2 receptor proteins in MI LVs was higher than in sham‐operated LVs 1 day (P < 0.05) and 4 wk (P < 0.01) after MI. In conclusion, melatonin synthesis in the pineal gland increased rapidly in response to the MI, supporting an important role for endogenous melatonin in protecting the heart after MI. The observed changes in the expression of MT1 and MT2 receptors suggest that melatonin receptors may be involved in mediating, at least, in part, the protective effects of melatonin in the heart after infarction.
Skin capacitance imaging of acne lesions
Authors: Xhauflaire‐Uhoda Emmanuelle , Piérard Gérald E.
Published: December 2006

Background: Little information is available about specific functional characteristics of skin in acneic patients.

Objective: To determine a capacitance mapping of lesional skin in acne in order to predict drug affinity according to the hydrophilic–lipophilic characteristics.

Method: Skin capacitance imaging based on silicon image sensor technology was used with the SkinChip® device.

Results: The non‐optical images obtained by this means clearly identified low capacitance comedones contrasting with a perifollicular rim of high capacitance in inflammatory papules. This method also showed sweating and the follicular pores distributed in a pinpoint pattern.

Conclusion: The objective mapping of skin surface capacitance showed large differences between acne lesions and the surrounding skin. The low capacitance of comedones contrasted with the high capacitance of the perifollicular area in inflammatory papules. These electrometric characteristics reflecting the corneocyte hydration may influence drug affinity to acne lesions.
Estimation of water content distribution in the skin using dualband polarization imaging
Authors: Arimoto Hidenobu
Published: December 2006

Background/purpose: A new enhancement imaging technique for visualizing two‐dimensional distribution of water content in human tissue is proposed based on optical properties such as reflectance spectra and the scattering from the skin surface.

Methods: The method consists of two fundamental functions: spectral filtering for estimating skin hydration and polarization control for the appropriate measurement depth. Spectral filtering is simply achieved by utilizing the bandpass filters, whereas the measurement depth control is performed by changing the polarization directions in front of a light source and a detector.

Results: The combined method of spectral filtering and polarization imaging effectively visualized the water content distribution in skin as a shading on a composed black and white image. The result was compared with the measured value of the capacitance method, and the result of the proposed method was validated.

Conclusion: Our results suggest that the proposed method enhances the scattering property in the skin according to the water content. Detailed discussions are given.
Reliability of measurement of skin ultrasonic properties in vivo: a potential technique for assessing irradiated skin
Authors: Huang Y. P. , Zheng Y. P. , Leung S. F. , Mak A. F. T.
Published: December 2006

Background/aims: Quantitative and objective technique to assess radiation‐induced tissue fibrosis is important for clinicians to estimate the efficiency of radiotherapeutic schemes. It has been widely reported that ultrasonic properties are sensitive to changes of acoustic scatterers in biological tissues. Therefore, measurement of ultrasonic properties may serve as a potential assessment technique for irradiated skins. The aim of the present study is to investigate the reliability of such measurement so as to evaluate its potentials for future clinical applications.

Methods: Ultrasonic parameters including attenuation slope (β), integrated attenuation (IA) and integrated backscatter (IBS) were measured for the frequency range of 10–25 MHz from echographic signals of the forearm and neck dermis of 20 normal subjects in vivo. The intra‐ and inter‐rater reliability of measurement was assessed in 10 normal subjects using intra‐class correlation coefficients (ICC) and Bland–Altman test.

Results: The intra‐ and inter‐rater measurement was demonstrated to be reliable as indicated by high ICC values generally larger than 0.80. In addition, the ultrasonic parameters could successfully differentiate the skins in the neck and forearm regions.

Conclusion: The measurement provided reliable information on the ultrasonic properties of the skins and could be potentially applied to comparative clinical trials to assess the late effects of radiotherapy on skins.
Evaluation of the effects of topical clobetasol propionate by visual score, electrical impedance and laser Doppler flowmetry
Authors: Emtestam L. , Kuzmina N. , Talme T.
Published: December 2006

Background/purpose: The intensity of steroid‐induced skin blanching is usually evaluated subjectively by a trained observer using a visual score although a few methods have been described for doing this objectively. In this study we wished to establish whether the effects of topical steroids can be detected by measuring the electrical impedance of the skin.

Methods: Ten healthy volunteers were treated with three concentrations of clobetasol propionate (0.005, 0.05, and 0.5 mg/mL) on the forearm covered by a dressing overnight. On the following morning, we assessed dermal blanching using a visual score, laser Doppler flowmetry and electrical impedance.

Results: Using the visual score, we found dose–response blanching at all concentrations of clobetasol propionate. The laser Doppler flow values declined significantly after the application of clobetasol propionate (0.005 mg/mL (P<0.01) and 0.5 mg/mL (P<0.05)), as compared with the test site treated with the vehicle alone. Electrical impedance showed a significant increase in phase index after the application of 0.05 mg (P<0.01) and 0.5 mg (P<0.01) of clobetasol propionate, and a significant reduction in real part index after of 0.05 mg/mL (P<0.05) and 0.5 mg/mL (P<0.05) compared with the test site treated with the vehicle alone. The magnitude index and imaginary part index were not affected by this steroid.

Conclusion: Our findings indicate that the dermal blanching induced by topical corticosteroids can be evaluated with a skin impedance spectrometer.
The Costs of Getting Ahead: Mexican Family System Changes After Immigration*
Authors: Bacallao Martica L. , Smokowski Paul R.
Published: December 2006

Abstract: This study explored how immigration influenced Mexican family relationships. Qualitative interviews were conducted with 12 adolescents and 14 parents from 10 undocumented Mexican families. Participants immigrated to North Carolina within the past 7 years. A conceptual model derived from the data using grounded theory methods suggested that, after immigration, parents had less time to spend with children because of demanding new jobs and mothers entering the work force. Decreased time as a family was associated with adolescents’ loneliness, isolation, and risk‐taking behavior. In response to perceived environmental threats, Mexican parents became authoritarian, precipitating parent‐adolescent conflict. Parent‐adolescent acculturation gaps were viewed as an asset as adolescents helped parents navigate within the new cultural system. Families coped with postimmigration changes by maintaining high levels of familism and enacting cultural traditions.
In the Context of Risk: Supportive Adults and the School Engagement of Middle School Students*
Authors: Woolley Michael E. , Bowen Gary L.
Published: December 2006

Abstract: Many students in the United States, particularly those from lower income or racially/ethnically diverse families, are exposed to clusters of risk factors that have a negative impact on school success. This study examined the association between the number of supportive and caring adults in the home, school, and neighborhood and the school engagement of students in early adolescence. Results revealed that students who reported such supportive adults in their lives also reported higher levels of psychological and behavioral engagement with their schooling. Additionally, including measures of environmental risk factors in analytical models of the school engagement of middle school students reduced otherwise statistically significant race/ethnicity differences to nonsignificance. Implications for practice and policy are discussed.
Distribution of the endophytic fungus, Neotyphodium occultans in naturalized Italian ryegrass in western Japan and its production of bioactive alkaloids known to repel insect pests
Authors: Sugawara K. , Inoue T. , Yamashita M. , Ohkubo H.
Published: December 2006

Endophytic fungi belonging to the genus Neotyphodium that form mutualistic associations with grasses of the subfamily Pooideae are ecologically and agriculturally important, producing mycotoxins that affect grazing animals and some insect pests. After our first report of naturalized Italian ryegrasses (Lolium multiflorum, annual ryegrass) infected with a Neotyphodium endophyte in Japan, the identity of this endophyte, the nature of its association with host grasses and its distribution, as well as the possible presence of toxic alkaloids have been of interest. To answer these questions we conducted surveys covering the western part of Japan to determine the distribution of infected Italian ryegrasses. Further, to identify the endophyte we used microscopy to determine its distribution in infected grasses and we applied DNA analysis using the ribosomal RNA gene (rDNA) to compare strains of this endophyte obtained from different geographic locations. Finally, we examined seed obtained from endophyte‐infected Italian ryegrasses using high‐performance liquid chromatograph (HPLC) and gas chromatograph. These studies indicated that naturalized Italian ryegrass in all three islands surveyed; Honshu, Kyushu and Shikoku, was frequently infected with N. occultans. N‐formyl loline, an insect toxin, and peramine, a feeding deterrent were detected in the infected seed samples, but neither ergovaline nor lolitrem B (causal agents of grazing animal toxicity) were detected. These chemical analyses indicated that N. occultans infection of Italian ryegrasses may provide some influence on the insect fauna of the area through the chemicals active against insects, but was unlikely to be toxic to grazing animals.
Effects of season, variety and botanical fractions on oxalate content of napiergrass (Pennisetum purpureum Schumach)
Authors: Rahman M. M. , Niimi M. , Ishii Y. , Kawamura O.
Published: December 2006

Various tropical grasses sometimes contain oxalate in sufficient concentration as to induce calcium deficiency in grazing animals. Napiergrass (Pennisetum purpureum), a useful tropical grass for ruminants was examined for oxalate levels with regard to season, variety and botanical fractions. It was observed that oxalate content was significantly (P < 0.001) affected by the season with the highest value (3.77%) being associated with early summer samples and the lowest value (1.76%) with late autumn samples. Compared to a normal, non‐dwarf variety, a dwarf variety exhibited a higher oxalate content but the difference was not statistically significant. With regard to the botanical fractions, oxalate content was significantly (P < 0.05) higher (2.78%) in leaf tissues compared to stem with leaf sheath (2.05%). In another experiment, a late, dwarf variety was re‐grown four times to evaluate re‐growth period effects on oxalate content during the early summer. Oxalate content increased gradually from the re‐growth period 1 (6 June to 28 June) to re‐growth period 3 (21 June to 12 July), and declined in re‐growth period 4 (28 June to 19 July). Results suggest that when napiergrass is grown in early summer, it could achieve oxalate levels that are toxic to ruminants.
Distribution model and spatial variation of cover in grassland vegetation
Authors: Chen Jun , Shiyomi Masae , Yamamura Yasuo , Hori Yoshimichi
Published: December 2006

In addition to biomass and frequency of occurrence, cover is often used as a measure in vegetation surveys. However, the theoretical and statistical bases underlying cover measures are not fully understood. Here, based on actual survey data, we showed that the frequency distributions of cover in grassland vegetation measured using the point‐grid plate method were well described by the beta distribution. The beta distribution expresses various types of cover frequency distributions, such as the ‘J’, ‘L’, ‘one‐peak’, ‘U’, and ‘rectangular’ types. We defined an index that expresses the spatial heterogeneity of cover based on the beta distribution. Further, we derived a simple method to estimate cover and the spatial heterogeneity index based on the beta distribution using a point‐grid plate. In this simple method, we classified the plant cover observed in each quadrat into the following three categories: cover c2(0 < c1 < c2 < 1). We counted the number of grid points only up toc2; when the cover exceededc2, counts were halted and the plant cover was assigned to cover >c2. This method saves time and labor. We showed that the parameter values (cover and spatial heterogeneity index) estimated from the data obtained for plant species in a grassland using the simple method agreed well with those obtained by counting all grid points covered by the plant species.
Versions of Monotone Paracompactness
Authors: STARES IAN S.
Published: December 2006

We consider the notion of monotone paracompactness introduced by Gartside and Moody. We show, in particular, that not all “possible” definitions for monotone paracompactness coincide, and we provide a new characterization of proto‐metrizability.
Comet Shoemaker‐Levy 9 Fragment Size Estimates: How Big Was the Parent Body?a
Authors: CRAWFORD DAVID A.
Published: December 2006

ABSTRACT: The impact of Comet Shoemaker‐Levy 9 on Jupiter in July, 1994 was the largest, most energetic impact event on a planet ever witnessed. Because it broke up during a close encounter with Jupiter in 1992, it was bright enough to be discovered more than a year prior to impact, allowing the scientific community an unprecedented opportunity to assess the effects such an event would have. Many excellent observations were made from Earth‐based telescopes, the Hubble Space Telescope (HST), and the Galileo spacecraft en route to Jupiter. In this paper, these observations are used in conjunction with computational simulations performed with the CTH shock‐physics hydrocode to determine the sizes of the fifteen fragments that made discernible impact features on the planet. To do this, CTH was equipped with a radiative ablation model and a postprocessing radiative ray‐trace capability that enabled light‐flux predictions (often called the impact flash) for the viewing geometries of Galileo and ground‐based observers. The five events recorded by Galileo were calibrated to give fragment size estimates. Compared against ground‐based and HST observations, these estimates were extended using a least‐squares analysis to assess the impacts of the remaining ten fragments. Some of the largest impacts (L, G, and K) were greater that 1 km in diameter, but the density of the fragments was low, about 0.25 g/cm3. The volume of the combined fifteen fragments would make a sphere 1.8 km in diameter. Assuming a prebreakup density of 0.5 g/cm3, the parent body of Shoemaker‐Levy 9 had a probable diameter of 1.4 km. The total kinetic energy of all the impacts was equivalent to the explosive yield of 300 Gigatons of TNT.
Cerebral Microvascular Alterations in Aging, Leukoaraiosis, and Alzheimer's Diseasea
Authors: MOODY DIXON M. , BROWN WILLIAM R. , CHALLA VENKATA R. , GHAZI‐BIRRY HANI S. , REBOUSSIN DAVID M.
Published: December 2006

ABSTRACT: We have been using alkaline phosphatase (AP) histochemical staining, formerly a research tool for the study of cerebral cortical vascular morphology, to examine pathological changes in the cortex and deep cerebral structures. Deep structures stain similarly to the cortex. The AP stain is found in the afferent vessels (small arteries, arterioles, and capillaries), but not in venules and veins. The stain is also present in leaky vessels, such as those in the area postrema. The vascular supply to the cerebrum is not homogeneous. Supply to the deep white matter, for instance, derives from the leptomeningeal border zone, and then medullary arterioles must wind their way for up to 4 cm before arriving at their ultimate destination. Adding to the difficulties, tortuosities develop in some of these vessels with aging. According to some calculations, hypertensive levels of blood pressure would be required to maintain irrigation through some of these vessels. We have identified a venous alteration that attends aging: periventricular venous collagenosis (PVC). PVC is a previously unrecognized, noninflammatory, mural disease of the periventricular veins. In severe cases, examples can be found of veins that are completely occluded by this process. PVC is found in 65% of subjects over 60 years old, and it strongly correlates with leukoaraiosis. In addition to previously mentioned aging‐related changes, we have found extreme tortuosity, multiplications, and aneurysms of the smallest arterioles and lumpy‐bumpy capillaries in the deep structures of patients with Alzheimer's disease.
Decreased Brain Glucose Metabolism in Microvessels from Patients with Alzheimer's Diseasea
Authors: MARCUS DAVID L. , FREEDMAN MICHAEL L.
Published: December 2006

ABSTRACT: We studied brain glucose metabolism in patients with Alzheimer's disease and age‐matched controls in vivo by PET and assessed brain glucose utilization and the phosphorylation constant K3 for hexokinase. In addition we determined in vitro the binding of 2DG and measured its phosphorylation to 2DG‐phosphate in cerebral microvessels obtained at autopsy from subjects with Alzheimer's disease and age‐matched controls. In patients with Alzheimer's disease we found a marked decrease in the kinetic constant K3 for the hexokinase, and a marked decrease in the overall metabolism of glucose in our PET studies; in microvessels there was a marked decrease in the affinity of 2DG and a decrease in hexokinase activity. Alzheimer's disease may be related to a complex alteration in brain glucose metabolism.
Hereditary Predisposition to Cancer
Authors: KNUDSON ALFRED G.
Published: December 2006

ABSTRACT: Both hereditary and environmental factors influence the risk of cancer. Four risk categories, or oncodemes, can exist for a particular kind of cancer, depending upon the presence of neither, one, or both factors: (1) spontaneous, or background; (2) hereditary; (3) environmental; (4) interactive. In the second, mutation imparts a high relative risk, but a generally low attributable risk; in the fourth, the opposite obtains. The second oncodeme contains genes that are also important for the non‐hereditary forms of the same cancer. Probably all forms of cancer exist in a dominantly heritable form. Most of the genes are tumor suppressors, although a few are oncogenes or DNA repair genes. The mutations are in most, if not all cases, maintained in a population by an equilibrium between mutation and selection.

Most of the cloned genes are expressed widely among tissues, yet there is typically some tumor specificity. Somatic mutations in second alleles at the relevant loci are necessary, but generally not sufficient for carcinogenesis, although they, in some instances, lead to the formation of benign precursor lesions. Further events are necessary for carcinogenesis. This is particularly true for carcinomas. The benign lesions appear to involve an increase in number of long‐lived cells that can accumulate other mutations. For some tumors, physiologic events, such as tissue growth at puberty or proliferation of embryonic stem cells, may produce this effect. Mutations of DNA mismatch repair genes underscore the effect that changes in somatic mutation rates can have, especially in the risk for multi‐event carcinomas. Conversely, these are the tumors that offer the greatest opportunity for prevention.
Neurotransmitters and Suicidal Behavior
Authors: ÅSBERG MARIE
Published: December 2006

ABSTRACT:Studies of neurotransmitter metabolites in cerebrospinal fluid (CSF) were initially focused on depressive illness. Although several studies have demonstrated low concentrations of the serotonin metabolite, 5‐hydroxyindoleacetic acid (5‐HIAA), and the dopamine metabolite, homovanillic acid (HVA), in depressed patients, these early studies may have been biased by concomitant administration of antidepressant drugs (which tend to lower CSF 5‐HIAA), amount of CSF drawn (there is a concentration gradient for both metabolites), and selection of control subjects. Once these methodological details are controlled for, the differences between depressed patients and controls are unimpressive.

However, there is a remarkably consistent association between low concentrations of CSF 5‐HIAA and suicidal behavior, as evidenced by over 20 studies. The association is not confined to depressive illness but has also been found in schizophrenia, personality disorder, and certain impulse control disorders (but, interstingly, not in bipolar disorder). A low concentration of CSF 5‐HIAA in a suicide attempter is associated with a substantial increase in short‐term suicide risk. CSF studies in violent criminals, and in nonhuman primates, suggest that aggression dyscontrol may partly explain the association between suicide and serotonin, which is of considerable theoretical interest. CSF 5‐HIAA determinations may also be helpful in the clinical assessment of suicide risk.
Suicide: A Four‐pathway Clinical‐Biochemical Model
Authors: FAWCETT JAN , BUSCH KATIE A. , JACOBS DOUGLAS , KRAVITZ HOWARD M. , FOGG LOUIS
Published: December 2006

Abstract This chapter, based on a review of recent research as well as data presented in this report, proposes four hypothetical pathways leading to suicide in clinical depression: (1) an acute pathway involving severe anxiety/agitation associated with high brain corticotrophin‐releasing factor (CRF or CRH) levels, (2) trait baseline and reactivity hopelessness, (3) severe anhedonia, and (4) trait impulsiveness associated with low brain serotonin turnover and low total cholesterol as a possible peripheral correlate.

Clinical research showing evidence for acute versus chronic high‐risk suicide factors and other studies linking severe anxiety/agitation to high CRF levels will be presented as associated with acute suicidal risk, which is potentially reversible with recognition and treatment. Evidence for anhedonia severity as a risk factor and trait, as well as evidence that baseline hopelessness and sensitivity are traits related to chronic suicide risk, will be presented. Finally, evidence relating low serum cholesterol to suicide in depressed inpatients will be presented in the context of literature suggesting a relationship between low serum cholesterol and violent death and suicide in population studies. Data suggesting a relationship between low serum cholesterol and decreased CSF 5‐HIAA, suggesting reduced serotonin turnover, will be presented, in light of prior studies relating low CSF 5‐HIAA and violent suicide. These data taken together suggest four pathways to suicide that are worth investigating in order to better understand the mechanisms leading to this behavior. Future possibilities and applications of these findings are discussed.
Nearest‐neighbor tree species combinations in tropical forest: the role of chance, and some consequences of high diversity
Authors: Lieberman Milton , Lieberman Diana
Published: December 2006

In three permanent inventory plots comprising 12.4 ha of undisturbed forest at La Selva, Costa Rica, all stems ≥10 cm dbh were mapped and identified to species. There were 1628, 1478 and 1954 trees in the plots, representing 168, 166 and 171 species respectively. We determined the species of each nearest‐neighbor pair of trees, and asked whether the occurrence of species pairs conforms to a simple random mixing model. If trees are randomly mixed in terms of species, the expected frequency of any nearest neighbor species combination is a function of the relative abundance of the two species. Departures from random mixing could arise from species interactions, differential responses to habitat, or both. The number of possible ij species combinations increases approximately as the square of the number of species. For the 168 species in plot 1, for example, there are 14 196 possible combinations. We compared the expected frequency of each species combination in the three plots (42 736 combinations in all) with observed frequencies. Over 98% of the combinations had observed frequencies of zero and expected frequencies close to zero. A consequence of high diversity is low density of most individual species, and exceedingly low frequencies of the vast majority of species combinations. For each of the 805 combinations with observed frequencies >0, we used simulation to generate a distribution of expected frequencies. We used a t‐test to compare the observed frequency with the mean of the simulated distribution for each combination. Only 40 combinations (0.09% of the possible species combinations in the plots) departed from expected frequencies; 39 combinations were more common, and one less common than expected. The overwhelming majority of nearest neighbor species combinations occur at frequencies predictable from their individual abundances.
Predation and priority effects in experimental zooplankton communities
Authors: Louette Gerald , De Meester Luc
Published: December 2006

During colonization of new habitats, the sequence of arrival among species is in many cases determined by chance. Priority effects imply that differences in arrival time may lead to long‐lasting differences in species dominance. To evaluate the importance of priority effects, we performed a community assembly experiment, manipulating the inoculation order of three large cladoceran zooplankton species. The inoculation treatments were crossed with a predation treatment to test whether the presence of a predator (larvae of the phantom midge Chaoborus) results in changes in the strength of species sorting and priority effects. Our results clearly demonstrate priority effects, but also that the presence of a predator impacts both community assembly and the strength of priority effects. In the predation‐free treatments, communities were dominated by either Daphnia magna or Daphnia obtusa, depending on the species arrival sequence. Whenever D. obtusa was inoculated after D. magna, the species displayed negative growth. In the presence of Chaoborus predation, the communities were generally dominated by the third species, Simocephalus vetulus. Here, the growth of D. magna was negative when the species was inoculated as second or third. Overall, our results underscore the importance of both priority effects and species sorting during community assembly.
Identifying recorder‐induced geographic bias in an Iberian butterfly database
Authors: Romo Helena , García‐Barros Enrique , Lobo Jorge M.
Published: December 2006

A database with comprehensive butterfly faunistic information from the Iberian Peninsula and the Balearic Islands was used to estimate inventory completeness as well as the environmental, spatial, and land‐use effects on sampling intensities, on a 50×50 km UTM grid. The degree of sampling effort was assessed by means of accumulation curves based on the Clench function. Using the General Linear Model regression procedure, the effects of 22 variables on the estimated sampling efforts were assessed. This combination of methods is proposed as a preliminary step in biodiversity studies, in order to evaluate not only the degree of geographic coverage of existing faunistic data, but also the amount and nature of the bias on the faunistic work done throughout the last two centuries. The degree of spatial effects on the data was greater than the effects of environmental or land‐use variables, although the latter two proved to be locally relevant. The results confirm previous findings that collecting is often skewed by relatively simple factors that affect collector activity, such as accessibility and attractiveness of sampling sites. With regard to Iberian and Balearic butterflies, adequate inventories on the scale investigated may probably suffice for further studies of the diversity of this insect group. Additionally, the results enabled us to develop general guide lines for the design of further faunistic work in the area.
How local extinction changes rarity: an example with Sonoran Desert fishes
Authors: Fagan William F. , Stephens Alisa J.
Published: December 2006

That spatially rare species may be predisposed to extinction is a common tenet of ecology. However, the opposite side of the relationship – how extinction alters spatial rarity – remains little explored. We used an extensive biodiversity database to contrast patterns of spatial rarity of a biogeographic assemblage of native Sonoran fishes before and after an extensive, decades‐long wave of extirpations. Focusing on 25 fish species native to the Lower Basin of the Colorado River, we analyzed two key aspects of spatial rarity: 1) species range sizes (expressed as kilometers of stream reach occupied) and 2) species’ co‐occurrence patterns. Native fish species that were spatially rare historically suffered disproportionate losses in occurrences. However, endemic species did not suffer increased losses relative to non‐endemic (but still native) species of comparable rarity. Species’ geographic range sizes were concordant through time, with spatially rare species remaining rare after extensive extirpations relative to species that were historically more widespread. In contrast, extirpations greatly disrupted patterns of species co‐occurrence on both local and regional scales. Over 50% of the species pairs that historically co‐occurred (in the same 5 km reach) no longer co‐occur anywhere in the Lower Basin, and species pairs that infrequently co‐occurred in historic times suffered greater proportional losses than did more widely co‐occurring pairs. Such changes in the relationship between spatial rarity and species richness deserve attention because they inhibit conservation planning (decreasing the efficiency of reserve design) and reduce interaction diversity altering opportunities for long‐term co‐evolutionary change.
Elevational patterns of frog species richness and endemic richness in the Hengduan Mountains, China: geometric constraints, area and climate effects
Authors: Fu Cuizhang , Hua Xia , Li Jun , Chang Zheng , Pu Zhichao , Chen Jiakuan
Published: December 2006

We studied frog biodiversity along an elevational gradient in the Hengduan Mountains, China. Endemic and non‐endemic elevational diversity patterns were examined individually. Competing hypotheses were also tested for these patterns. Species richness of total frogs, endemics and non‐endemics peaked at mid‐elevations. The peak in endemic species richness was at higher elevations than the maxima of total species richness. Endemic species richness followed the mid‐domain model predictions, and showed a nonlinear relationship with temperature. Water and energy were the most important variables in explaining elevational patterns of non‐endemic species richness. A suite of interacting climatic and geometric factors best explained total species richness patterns along the elevational gradient. We suggest that the mid‐domain effect was an important factor to explain elevational richness patterns, especially in regions with high endemism.
How do birds search for breeding areas at the landscape level? Interpatch movements of male ortolan buntings
Authors: Dale Svein , Steifetten Øyvind , S. Osiejuk Tomasz , Losak Katarzyna , P. Cygan Jakub
Published: December 2006

Animal movements at large spatial scales are of great importance in population ecology, yet little is known due to practical problems following individuals across landscapes. We studied the whole Norwegian population of a small songbird (ortolan bunting, Emberiza hortulana) occupying habitat patches dispersed over nearly 500 km2. Movements of colour‐ringed males were monitored during ten years, and extensive long‐distance dispersal was recorded. More than half of all cases of breeding dispersal took place within one breeding season, and males moved up to 43 km between singing territories, using 1–22 d. Natal dispersal was usually to a habitat patch close to the natal patch, or within the natal patch if it was large. Breeding dispersal movements were often long‐distance, beyond neighbouring patches, and up to 11–19 patches were overflown. Movements of at least 6–9 km across areas of unsuitable habitat occurred regularly. The number of patches visited was low (1–4) even though search costs in terms of time spent moving from one site to another were relatively low (often only a few days even for distances >10 km). Most males seemed to use a threshold tactic when choosing a patch, but returns to previously visited patches were recorded, including some cases of commuting. In conclusion, male ortolan buntings have a surprising ability to move quickly at the landscape level, and this resulted in a high connectivity of patches. We discuss our results in relation to optimal searching strategies, in particular the use of within‐breeding season versus post‐breeding season search, conspecific attraction and adaptive late arrival of young birds.
Reversing habitat loss: deciduous habitat fragmentation matters to birds in a larch plantation matrix
Authors: Yamaura Yuichi , Katoh Kazuhiro , Takahashi Toshimori
Published: December 2006

Whereas matrix management has recently been suggested as a useful tool in biodiversity conservation, patterns and processes within matrices remain unknown. We examined the effects of the loss and fragmentation (configuration) of original deciduous habitats on birds in larch plantation matrix in the winter and during the breeding season in a montane region in Nagano Prefecture, central Japan. Birds were counted using a plot‐count method from 32 (winter) and 46 (breeding) matrix (plantation) sites with a range of surrounding habitat loss and fragmentation at a 1600‐m scale. Birds were assigned to species groups based on ecological traits, and three groups for which larch plantation would function as low‐quality matrix were analyzed. Bird occurrences were explained primarily by habitat structure. Although the effects of landscape structure were less than those of habitat structure, three of five groups across the two seasons experienced significant landscape effects. All effects were of habitat fragmentation (scatteredness of deciduous habitats), i.e. two groups (flycatchers in the breeding season and tree nesters in both seasons) frequently occurred in matrix surrounded by highly scattered deciduous habitats. However, most of these effects were confounded by local habitat structure. That is, the variation in bird occurrences explained purely by fragmentation variables was <6%. Nonetheless, because these effects were marginally significant at p<0.10, there was some support for fragmentation effects after covariation with habitat structure was considered. Based on these results and associated theoretical studies, we hypothesized that habitat fragmentation leads to loss of individuals and is more important than habitat loss in landscapes with a structurally similar matrix. We also hypothesized that matrix within landscapes with highly scattered habitats should be managed with high priority.
Genetic and phenotypic associations in morphological traits: a long term study of great reed warblersAcrocephalus arundinaceus
Authors: Åkesson Mikael , Bensch Staffan , Hasselquist Dennis
Published: December 2006

We present estimates of standardized selection (directional and quadratic) differentials via reproductive success on eight morphological traits in a newly founded long‐term study population of great reed warblersAcrocephalus arundinaceusin Sweden. In order to predict the evolutionary response to selection in these traits we present estimates of heritabilities (h2), phenotypic (rP) and genetic (rA) correlations among the same traits. We also examined the extent of parental effects in the expression of the phenotypic traits. Overall, the population is subject to low levels of directional selection and higher levels of stabilizing selection. This makes us predict that the population is changing very little if anything, even though h2in many cases are considerable. Midparent‐midoffspring h2ranged from 0.14 and 0.94 (mean 0.58) and were significant for seven of eight traits. We found indications of positive maternal effects in tarsus length. Phenotypic correlations between traits ranged from 0.02 to 0.43 (mean 0.15) and showed generally much lower values than the corresponding genetic correlations that ranged between 0.08 and 1.04 (mean 0.46). Overall, the correlation between rPand rAwas significant, although moderate, but they tended to differ in magnitude, possibly due to overestimation of additive covariance between traits.
Ranging behaviour of male capercaillie Tetrao urogallus outside the lekking ground in spring
Authors: Eliassen Sigrunn , Wegge Per
Published: December 2006

During the breeding season, adult male capercaillies Tetrao urogallus display on leks in the early morning. During the day, they occupy more or less exclusive home ranges within 1 km of the lekking ground, but little is known about their movements and range use patterns during this period. In three spring seasons we monitored the daily movement of 15 radio‐tagged adult males, associated with six different leks, in a coniferous forest of southeast Norway. The objective was to relate dynamics of male movement and spatial distribution to changes in food resource availability and mating‐related activities. In late winter, males exhibited a pattern of short daily relocations (distance between bird locations in successive days) within small ranges. Relocation distances and home ranges then increased markedly during two weeks preceeding the main mating period. During the mating and post‐mating periods, movements again decreased, followed by another short peak at the time when females with depredated nests return to the lek for remating. These temporal changes in range use were not related to changes in food resources and probably not to shifts in anti‐predator behaviour, and they differed between age groups: The increase in relocation distance during the pre‐mating period was most pronounced among young resident males (3 and 4 year‐olds), and range area of older males were smaller and did not increase as much during this period. The observed age‐related changes in space use may reflect an alternative mating strategy by young and subdominant males; they seek out females outside the lekking ground where competition from more dominant males is less intense.
Red‐winged blackbirds Ageliaus phoeniceus respond differently to song types with different performance levels
Authors: Cramer Emily R. A. , Jordan Price J.
Published: December 2006

Physical constraints on animal signals can have important consequences for communication. For bird songs that include a trill, performance is physically constrained by a trade‐off between the rate at which notes are repeated in the trill and the sound frequency range covered, such that a trill cannot exceed a certain frequency range for a given note repetition rate. Producing trills that are closer to this performance limit is presumably more challenging for birds than producing trills that are farther from it. Male red‐winged blackbirds Ageliaus phoeniceus have repertoires of two to eight song types containing trills that span a range of performance levels. We determined the approximate trill performance maximum for a population of red‐winged blackbirds, then conducted playback experiments to measure the responses of territorial males to song types with either high or low performance levels relative to this limit. Males responded significantly more strongly to songs containing low performance trills. Our results show that male red‐winged blackbirds can discriminate between different song performance levels, suggesting that vocal proficiency plays a role in male‐male interactions.
Functional richness of local hoverfly communities (Diptera, Syrphidae) in response to land use across temperate Europe
Authors: Schweiger Oliver , Musche Martin , Bailey Debra , Billeter Regula , Diekötter Tim , Hendrickx Frederik , Herzog Felix , Liira Jaan , Maelfait Jean‐Pierre , Speelmans Marjan , Dziock Frank
Published: December 2006

Environmental change is not likely to act on biodiversity in a random manner, but rather according to species traits that affect assembly processes, thus, having potentially serious consequences on ecological functions. We investigated the effects of anthropogenic land use on functional richness of local hoverfly communities of 24 agricultural landscapes across temperate Europe. A multivariate ordination separated seven functional groups based on resource use, niche characteristics and response type. Intensive land use reduced functional richness, but each functional group responded in a unique way. Species richness of generalist groups was nearly unaffected. Local habitat quality mainly affected specialist groups, while land use affected intermediate groups of rather common species. We infer that high species richness within functional groups alone is no guarantee for maintaining functional richness. Thus, it is not species richness per se that improves insurance of functional diversity against environmental pressures but the degree of dissimilarity within each functional group.