bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophysiological Deficiency in Peripheral Nerve Induced by Treatment for 12 Weeks with 2‐Butenenitrile, 3‐Butenenitrile, cis‐2‐Pentenenitrile and 3, 3′‐Iminodipropionitrile in Rats
Authors: Gagnaire François , Marignac Brigitte
Published: March 2009

Abstract: Motor and sensory conduction velocities and amplitudes of the sensory and motor action potentials of the tail nerve were studied in male Sprague‐Dawley rats during subchronic oral treatment with three unsaturated aliphatic nitriles. The rats were given, by gastric intubation, doses of 10, 20 and 40 mg × kg–1 3‐butenenitrile (allyl cyanide) and 25, 50 and 100 mg × kg–1 of either cis/trans‐2‐butenenitrile (crotononitrile) or cis‐2‐pentenenitrile once a day, 5 days per week for 12 weeks. Moreover, 3, 3′‐iminodipropionitrile was administered likewise at doses of 25, 50 and 100 mg × kg–1 as reference neurotoxicant. Oral administration of the three unsaturated nitriles produced deafness and absence of reaction when the animals were subject to droptest. Moreover, rats exhibited both time‐ and concentration‐dependent decreases in motor and sensory conduction velocities and amplitudes of the sensory action potentials. Nerve conduction velocities were partially reversible after 8 weeks of recovery. Rats receiving 3, 3′‐iminodipropionitrile developed deafness, head weaving and significant irreversive deficiencies in all the electrophysiological parameters studied. Further toxicological studies with related unsaturated nitriles should be carried out to determine the potential importance of the cis/trans isomerism in the observed neurotoxicity.
The Influence of Humic Substances on the Absorption and Distribution of Cadmium in Mice
Authors: Lind Ylva , Glynn Anders Wicklund
Published: March 2009

Abstract: The complex binding of cadmium ions to humic and fulvic acids in water may influence the absorption and distribution of drinking‐water Cd in humans. Thus, in the present study mice were given a single oral dose of Cd (109CdCl2, 25 μg/l) in 100 μl Millipore® water containing different concentrations of humic compounds (0, 1, 10 and 100 mg dissolved organic carbon/l). The complex binding of Cd was studied by dialysis. At neutral pH, 1 mg dissolved organic carbon/l caused complex binding of more than 50% of the Cd, whereas more than 90% of Cd was bound at 10 and 100 mg dissolved organic carbon/l. At pH 3 the complex binding of Cd decreased somewhat, but over 90%) of the Cd was bound at 100 mg dissolved organic carbon/l. Complex binding of Cd increased the lipid solubility of Cd, expressed as an octanol/water partition coefficient, Nevertheless, more than 99% of the bound Cd was present as hydrophilic binding forms. Irrespective of the bound of Cd, the intestinal uptake and intracellular distribution (gel filtration on Sephadex G‐75 column) were not affected by the humic substances 6 hr after dosage. Moreover, complex binding did not influence the intestinal absorption of Cd 24 hr after exposure. The median Cd retention in the kidneys of the 100 mg dissolved organic carbon/1 group was 23%> and 46% lower than that of the control group 6 and 24 hr after administration, respectively, indicating alterations in the distribution of Cd after absorption. Thus humic substances may affect the metabolism of toxic heavy metals, such as Cd, in vivo in mice, indicating that the presence of humic and fulvic acids in drinking water should be considered in future risk assessments of metals in drinking water.
Nicotinic Acid and Pyridoxine Modulate Arachidonic Acid Metabolism in vitro and ex vivo in Man
Authors: Saareks Virpi , Mucha Istvàn , Sievi Eeva , Riutta Asko
Published: March 2009

Abstract: The in vitro effects of nicotinic acid (10–1000 μM), pyridoxine (0.1–500 μM) and pyridoxal‐5′‐phosphate (0.1–500 μM) and the ex vivo effects of nicotinic acid (2500 mg orally during 12 h) and pyridoxine (600 mg orally daily for seven days) on arachidonic acid metabolism were investigated in calcium ionophore A23187 (calcimycin)‐stimulated human whole blood. In vitro nicotinic acid stimulated prostaglandin E2, thromboxane B2 and leukotriene E4 synthesis. Pyridoxine at all concentrations and pyridoxal‐5′‐phosphate at the highest concentration stimulated prostaglandin E2 and thromboxane B2 production, but had no effect on leukotriene E4 synthesis. Nicotinic acid treatment increased ex vivo prostaglandin E2, thromboxane B2 and leukotriene E4 synthesis to 185%, 165% and 175% of the initial values, respectively. In the pyridoxine‐treated subjects, ex vivo prostaglandin E2, thromboxane B2 and leukotriene E4 synthesis was decreased after seven days to 75%, 65% and 45% of the initial values, respectively. In the present study the effects of nicotinic acid on the 5‐lipoxygenase pathway in arachidonic acid metabolism were studied for the first time and the drug was found to stimulate this pathway in vitro and ex vivo. In vitro pyridoxine and pyridoxal‐5′‐phosphate had no effect on the 5‐lipoxygenase pathway. The inhibition of leukotriene synthesis by pyridoxine ex vivo might be of therapeutic importance.
Airway Hyperresponsiveness in Anaesthetised Guinea‐Pigs 18–24 Hours after Antigen Inhalation Does Not Occur with All Intravenously Administered Spasmogens
Authors: Johnson Alexia , Broadley Kenneth J.
Published: March 2009

Abstract:Actively sensitised guinea‐pigs were exposed to inhalation challenges with ovalbumin aerosol (macro‐ and microshock) and airway responsiveness to six intravenously administered spasmogens was evaluated 18 to 24 hr later in the anaesthetised animal. An increase in airway sensitivity was defined as a significant leftward shift of the dose‐response curve when compared with saline‐challenged control sensitized animals. After ovalbumin‐macroshock (1% ovalbumin for 2 min. with mepyramine cover against fatal anaphylaxis), airway hyperresponsiveness was seen to 5‐HT, the thromboxane A2‐mimetic, U‐46619, and bradykinin but not to methacholine, histamine or substance P. A similar pattern was seen after ovalbumin‐microshock (0.01% ovalbumin for 60 min.), with induction of airway hyperreactivity to 5‐HT and U‐46619 but not methacholine or histamine. When the U‐46619 dose‐response curve was constructed following treatment of the animals with atropine (1 mg/kg, intravenously), airway hyperresponsiveness was no longer significant. As an index of airway inflammation, lung weights were significantly heavier in ovalbumin‐challenged animals, than in saline‐challenged controls. The results of this study with intravenously administered spasmogens does not support claims that ovalbumin‐induced airway hyperreactivity in the guinea‐pig is a ‘non‐specific’phenomenon.
Effects of Repeated Low Dose Administration and Withdrawal of Haloperidol on Sexual Behaviour of Male Rats
Authors: Tupala Erkki , Haapalinna Antti , Viitamaa Timo , Männistö Pekka T. , Saano Veijo
Published: March 2009

Abstract:Neuroleptics are known to cause anhedonia and attenuate sexual behaviour at therapeutic doses in humans. These effects are assumed to result from the dopamine antagonism of the drugs. It has been observed that a mixed dopamine D1/D2antagonist, haloperidol, may cause a reduction in the number of intromissions required to achieve ejaculation. On the other hand, dopamine antagonists are considered unable to modify sexual behaviour once the copulatory sequence is initiated. In this study, male rats received low doses of haloperidol (30 or 60 μg/kg) before the investigation of sexual behaviour in five consecutive days and the mating test was repeated after withdrawal periods of four and five days. Haloperidol dose‐dependently reduced intromission frequency, and this effect was maintained for four days after withdrawal. Ejaculation latency was reduced in all groups, including controls. The results indicate that at low doses haloperidol dose‐dependently reduces intromission frequency, and the effect of a repeated dosage may persist several days after cessation of medication.
Fluvoxamine is a More Potent Inhibitor of Lidocaine Metabolism than Ketoconazole and Erythromycinin vitro
Authors: Wang Jun‐Sheng , Backman Janne T. , Wen Xia , Taavitsainen Päivi , Neuvonen Pertti J. , Kivistö Kari T.
Published: March 2009

AbstractCYP3A4 is generally believed to be the major CYP enzyme involved in the biotransformation of lidocaine in man; however, recentin vivostudies suggest that this may not be the case. We have examined the effects of the CYP3A4 inhibitors erythromycin and ketoconazole and the CYP1A2 inhibitor fluvoxamine on theN‐deethylation, i.e. formation of monoethylglycinexylidide (MEGX), and 3‐hydroxylation of lidocaine by human liver microsomes. The experiments were carried out at lidocaine concentrations of 5 μM (clinically relevant concentration) and 800 μM. The formation of both MEGX and 3‐hydroxylidocaine was best described by a two‐enzyme model. At 5 μM of lidocaine, fluvoxamine was a potent inhibitor of the formation of MEGX (IC501.2 μM). Ketoconazole and erythromycin also showed an inhibitory effect on MEGX formation, but ketoconazole (IC508.5 μM) was a much more potent inhibitor than erythromycin (IC50200 μM). At 800 μM of lidocaine, fluvoxamine (IC5020.7 μM) and ketoconazole (IC5020.4 μM) displayed a modest inhibitory effect on MEGX formation, whereas erythromycin was a weak inhibitor (IC50>250 μM). The 3‐hydroxylation of lidocaine was potently inhibited by fluvoxamine at both lidocaine concentrations (IC500.16 μM at 5 μM and 1.8 μM at 800 μM). Erythromycin and ketoconazole showed a clear inhibitory effect on the 3‐hydroxylation of lidocaine at 5 μM of lidocaine (IC509.9 μM and 13.9 μM, respectively), but did not show a consistent effect at 800 μM of lidocaine (IC50>250 μM and 75.0 μM, respectively). Although further studies are needed to elucidate the role of distinct CYP enzymes in the biotransformation of lidocaine in humans, the findings of this study suggest that while both CYP1A2 and CYP3A4 are involved in the metabolism of lidocaine by human liver microsomes, CYP1A2 is the more important isoform at clinically relevant lidocaine concentrations.
Microdialysis Studies on the Action of Tolcapone on Pharmacologically‐Elevated Extracellular Dopamine Levels in Conscious Rats
Authors: Huotari Marko , Gainetdinov Raul , Männistö Pekka T.
Published: March 2009

AbstractTo elucidate the importance of catechol‐O‐methyltransferase, we performed striatal microdialysis studies in conscious rats given tolcapone, an inhibitor of catechol‐O‐methyltransferase, together with four compounds each of which elevates the extracellular dopamine content through a different mechanism. Tolcapone itself did not alter dopamine levels in the striatal microdialysis fluid but increased DOPAC and decreased homovanillic acid levels. However, tolcapone pretreatment (30 mg/kg) multiplied the already high dopamine levels after levodopa, and less so the moderately elevated dopamine levels after GBR‐12909 (at 20 mg/kg) alone, but the minor (insignificant) dopamine‐elevating effects of haloperidol and (+)‐U232 were not altered. In all cases, a tolcapone pretreatment decreased homovanillic acid levels and elevated DOPAC levels. In further combination studies, GBR‐12909 did not alter significantly the effects of levodopa/carbidopa on dopamine, DOPAC and homovanillic acid levels. In these rats, tolcapone enhanced the effect of GBR‐12909 on extracellular dopamine but not on DOPAC. In conclusion, when levodopa and carbidopa are given together, COMT inhibition becomes extremely meaningful, and dopamine levels are multiplied by tolcapone. Otherwise, tolcapone is able to further elevate extracellular dopamine levels only when dopamine turnover is normal or low but not when it is high. Overall, the role of COMT in the elimination of synaptic dopamine remains minor compared to the dominance of the reuptake process.
Human Islets in Mixed Islet Grafts Protect Mouse Pancreatic β‐Cells from Alloxan Toxicity
Authors: Tyrberg Björn , Eizirik Décio L. , Marklund Stefan L. , Olejnicka Beata , Madsen Ole D. , Andersson Arne
Published: March 2009

Abstract We have previously shown that human β‐cells are resistant to the toxic effects of alloxan. In order to further clarify this characteristic of human islets, we investigated whether these cells might transfer their alloxan resistance to alloxan‐sensitive rat or mouse islets. Islets from two species (human‐mouse or rat‐mouse) were mixed into one graft, which was implanted into the subcapsular kidney space of nude mice. Alloxan or saline was injected intravenously two weeks after implantation and one week thereafter the mice were killed. The number of grafted and endogenous β‐cells were evaluated by a semi‐quantitative method after immunohistochemistry. Human islet production of the scavenging enzymes extracellular superoxide dismutase and plasma glutathione peroxidase were analyzed with ELISA‐techniques, and mouse and human islet hydrogen peroxide breakdown activity were monitored with a horseradish peroxidase‐dependent assay. Mouse β‐cells transplanted together with human islets were protected against alloxan cytotoxicity. Rat islets did not protect mouse β‐cells against alloxan, suggesting that the mixing procedure as such did not impose the protection. Production of extracellular superoxide dismutase and plasma glutathione peroxidase by human islets was very low. Moreover, H2O2 breakdown in vitro, did not differ between human and mouse islets. Alloxan‐insensitive human islets protect mouse β‐cells against alloxan‐induced lesions, suggesting that yet to be identified extracellular factors are involved in human islet resistance to alloxan toxicity.
Acute Toxicity Profile of Maprotiline in the Rat
Authors: Darcy Philip , Dredge Keith , Kellehir Padraig , Kelly John P. , Leonard Brian E. , Chambers Philip L.
Published: March 2009

Abstract The aim of the present study was to examine the toxic effects of single oral administrations of the antidepressant maprotiline at 150 mg/kg or 300 mg/kg using female Sprague‐Dawley rats. Body‐weight gain was significantly reduced in the group receiving 300 mg/kg on days 1–5 of the study (P<0.01). A significant reduction in food and water intake was observed on days 1 and 2 of the study (P<0.01) in the 300 mg/kg group and on day 1 in the 150 mg/kg group (P<0.05). There was a significant decrease in nocturnal home cage activity over the first five days of the study in the 300 mg/kg group (P<0.01). A significant hypothermic response was observed in both 150 and 300 mg/kg groups at 1, 2 and 4 hr after dosing (P<0.01), that had returned to control values within 8 hr following administration. This study demonstrates that a multi‐parameter approach is appropriate for the investigation of high doses of antidepressants in rodents.
Effect of Acute and Chronic Administration of Sodium Valproate on Lipid Peroxidation and Antioxidant System in Rat Liver
Authors: Seçkin Şule , Başaran‐Küçükgergin Canan , Uysal Müjdat
Published: March 2009

AbstractChanges in glutathione and lipid peroxide levels as well as in the activities of superoxide dismutase, glutathione peroxidase, catalase and glutathione‐S‐transferase have been studied in rats after acute and chronic sodium valproate treatments. Glutathione levels were decreased only after acute sodium valproate treatment. Neither acute nor chronic treatment influenced lipid peroxidation but induced glutathione‐S‐transferase activity significantly. On the other hand, no alterations in glutathione peroxidase and superoxide dismutase activities were found, except slight induction of catalase activity after acute administration of sodium valproate. These results indicate that sodium valproate treatment did not induce oxidative stress in the liver.
Understorey plant and soil responses to disturbance and increased nitrogen in boreal forests
Authors: Manninen O.H. , Stark S. , Kytöviita M.‐M. , Lampinen L. , Tolvanen A.
Published: March 2009

Question: How do N fertilization and disturbance affect the understorey vegetation, microbial properties and soil nutrient concentration in boreal forests?

Location: Kuusamo (66°22′N; 29°18′E) and Oulu (65°02′N; 25°47′E) in northern Finland.

Methods: We conducted a fully factorial experiment with three factors: site (two levels), N fertilization (four levels) and disturbance (two levels). We measured treatment effects on understorey biomass, vegetation structure, and plant, soil and microbial N and C concentrations.

Results: The understorey biomass was not affected by fertilization either in the control or in the disturbance treatment. Fertilization reduced the biomass of deciduous Vaccinium myrtillus. Disturbance had a negative effect on the biomass of V. myrtillus and evergreen Vaccinium vitis‐idaea and decreased the relative proportion of evergreen species. Fertilization and disturbance increased the biomass of grass Deschampsia flexuosa and the relative proportion of graminoids. The amount of NH4+ increased in soil after fertilization, and microbial C decreased after disturbance.

Conclusions: Our results suggest that the growth of slow‐growing Vaccinium species and soil microbes in boreal forests are not limited by N availability. However, significant changes in the proportion of dwarf shrubs to graminoids and a decrease in the biomass of V. myrtillus demonstrate the susceptibility of understorey vegetation to N enrichment. N enrichment and disturbance seem to have similar effects on understorey vegetation. Consequently, increasing N does not affect the rate or the direction of recovery after disturbance. Moreover, our study demonstrates the importance of understorey vegetation as a C source for soil microbes in boreal forests.
The effects of leaf size, leaf habit, and leaf form on leaf/stem relationships in plant twigs of temperate woody species
Authors: Yang Dongmei , Li Guoyong , Sun Shucun
Published: March 2009

Question: Do thick‐twigged/large‐leaf species have an advantage in leaf display over their counterparts, and what are the effects of leaf habit and leaf form on the leaf‐stem relationship in plant twigs of temperature broadleaf woody species?

Location: Gongga Mountain, southwest China.

Methods: (1) We investigated stem cross‐sectional area and stem mass, leaf area and leaf/lamina mass of plant twigs (terminal branches of current‐year shoots) of 89 species belonging to 55 genera in 31 families. (2) Data were analyzed to determine leaf‐stem scaling relationships using both the Model type II regression method and the phylogenetically independent comparative (PIC) method.

Results: (1) Significant, positive allometric relationships were found between twig cross‐sectional area and total leaf area supported by the twig, and between the cross‐sectional area and individual leaf area, suggesting that species with large leaves and thick twigs could support a disproportionately greater leaf area for a given twig cross‐sectional area. (2) However, the scaling relationships between twig stem mass and total leaf area and between stem mass and total lamina mass were approximately isometric, which indicates that the efficiency of deploying leaf area and lamina mass was independent of leaf size and twig size. The results of PIC were consistent with these correlations. (3) The evergreen species were usually smaller in total leaf area for a given twig stem investment in terms of both cross‐sectional area and stem mass, compared to deciduous species. Leaf mass per area (LMA) was negatively associated with the stem efficiency in deploying leaf area. (4) Compound leaf species could usually support a larger leaf area for a given twig stem mass and were usually larger in both leaf size and twig size than simple leaf species.

Conclusions: Generally, thick‐twigged/large‐leaf species do not have an advantage over their counterparts in deploying photosynthetic compartments for a given twig stem investment. Leaf habit and leaf form types can modify leaf‐stem scaling relationships, possibly because of contrasting leaf properties. The leaf size‐twig size spectrum is related to the LMA‐leaf life span dimension of plant life history strategies.
Biting the hand that feeds: the invasive grass Schismus barbatus (Poaceae) is facilitated by, but reduces establishment of, the native shrub Ambrosia dumosa (Asteraceae)
Authors: Rodríguez‐Buriticá Susana , Miriti Maria N.
Published: March 2009

Question: We present a study of positive and negative interactions between the invasive grass Schismus barbatus (Poaceae) and Ambrosia dumosa (Asteraceae). Ambrosia facilitates seedling establishment, and such facilitation may accelerate invasion of exotic species, which, in turn, may reduce establishment of native plants.

Location: Joshua Tree National Park, California, USA.

Methods: During 2003‐2004, we used field surveys to characterize the natural spatial distribution of Schismus in relation to native shrubs, and experimentally manipulated seed rain of Ambrosia and Schismus at three distances from adult Ambrosia canopies. We measured percentage germination and individual performance of both species. Field data were complemented by a greenhouse experiment that measured competition between Ambrosia seedlings and Schismus planted at three densities and five relative abundances under controlled conditions.

Results: Field surveys showed that the density of Schismus is independent of Ambrosia shrubs, but growth is enhanced near shrub canopies. In our field experiment Schismus is facilitated by adult Ambrosia. Under controlled conditions, Schismus does not respond to the density of Ambrosia seedlings, but changes in density of Schismus decreased performance of Ambrosia seedlings.

Conclusion: Schismus invasion may be detrimental to native perennial plant populations. Although a reduction of seedling establishment is not usually expected to slow population growth of long‐lived perennials, recent unprecedented adult mortality in this community, and the well‐documented facilitative role of Ambrosia, suggest that Schismus invasion may be of high ecological significance.
Air humidity, soil moisture and soil chemistry as determinants of the herb layer composition in European beech forests
Authors: Leuschner Christoph , Lendzion Jasmin
Published: March 2009

Question: What role does air humidity play as an environmental factor for the abundance and distribution of temperate woodland herbs?

Location: Beech forests on calcareous soils in southern lower Saxony, central Germany.

Methods: The abundance of woodland herb species and total herb cover were investigated in 60 plots with contrasting exposure, slope angle and relief type. On all plots, air humidity, air temperature, soil moisture, photosynthetically active radiation, pH (H2O) and concentration of salt‐exchangeable Ca, Mg and K were measured. Species‐environment relationships were analysed with multiple regression analysis and CCA.

Results: Air humidity (RH), soil moisture and the concentration of exchangeable Ca and K, but not light, C/N ratio and the concentration of exchangeable Mg were identified as the most important abiotic factors influencing the cover of the most abundant plant species and total herb cover. RH varied substantially across the different forest floor site types and influenced species abundance independent of soil moisture. In several species (including Mercurialis perennis and Impatiens noli‐tangere), RH was found to be a key environmental factor. Other species such as Aegopodium podagraria and Lamiastrum galeobdolon depended more on elevated soil moisture, while RH was less important.

Conclusions: This study showed that the distribution of widespread temperate woodland herb species depends on high air humidity, and that certain sensitive species do not occur at sites with reduced air humidity even though soil moisture is high. Thus, high air humidity and ample soil moisture are key abiotic factors in beech forests on calcareous soils. Shade level (PAR) was found to be of secondary importance.
Discriminating trait‐convergence and trait‐divergence assembly patterns in ecological community gradients
Authors: Pillar Valério D. , Duarte Leandro da S. , Sosinski Enio E. , Joner Fernando
Published: March 2009

Question: Whereas similar ecological requirements lead to trait‐convergence assembly patterns (TCAP) of species in communities, the interactions controlling how species associate produce trait‐divergence assembly patterns (TDAP). Yet, the linking of the latter to community processes has so far only been suggested. We offer a method to elucidate TCAP and TDAP in ecological community gradients that will help fill this gap.

Method: We evaluated the correlation between trait‐based described communities and ecological gradients, and using partial correlation, we separated the fractions reflecting TCAP and TDAP. The required input data matrices describe operational taxonomic units (OTUs) by traits, communities by the quantities or presence‐absence of these OTUs, and community sites by ecological variables. We defined plant functional types (PFTs) or species as community components after fuzzy weighting by the traits. The measured correlations for TCAP and TDAP were tested by permutation. The null model for TDAP preserves the trait convergence, the structure intrinsic in the fuzzy types, and community total abundances and autocorrelation.

Results: We applied the method to trait‐based data from plant communities in south Brazil, one set in natural grassland experimental plots under different nitrogen and grazing levels, and another in sapling communities colonizing Araucaria forest patches of increasing size in a forest‐grassland mosaic. In these cases, depending on the traits considered, we found strong evidence of either TCAP or TDAP, or both, that was related to the environmental gradients.

Conclusions: The method developed is able to reveal TCAP and TDAP that are more likely to be functional for specified ecological gradients, allowing establishment of objective hypotheses on their links to community processes.
Do changes in rainfall patterns affect semiarid annual plant communities?
Authors: Miranda Juan de Dios , Padilla F.M. , Lázaro R. , Pugnaire F.I.
Published: March 2009

Question: Climate change models forecast a reduction in annual precipitation and more extreme events (less rainy days and longer drought periods between rainfall events), which may have profound effects on terrestrial ecosystems. Plant growth, population and community dynamics in dry environments are likely to be affected by these changes since productivity is already limited by water availability. We tested the effects of reduced precipitation and fewer rain events on three semiarid plant communities dominated by annual species.

Location: Three semiarid plant communities from Almería province (SE Spain).

Methods: Rain‐out shelters were set up in each community and watering quantity and frequency were manipulated from autumn to early summer. Plant productivity, cover and diversity were measured at the end of the experimental period.

Results: We found that a 50% reduction in watering reduced productivity, plant cover and diversity in all three communities. However, neither the 25% reduction in watering nor changes in the frequency of watering events affected these parameters.

Conclusions: The lack of response to small reductions in water could be due to the identity and resistance of the plant communities involved, which are adapted to rainfall variability characteristic of arid environments. Therefore, a rainfall reduction of 25% or less may not affect these plant communities in the short term, although higher reductions or long‐term changes in water availability would probably reduce productivity and diversity in these communities.
Recruitment limitation of forest communities in a degraded Mediterranean landscape
Authors: Mendoza Irene , Gómez‐Aparicio Lorena , Zamora Regino , Matías Luis
Published: March 2009

Question: How does habitat degradation affect recruitment limitation and its components (seed limitation versus establishment limitation) of woody plant communities in a Mediterranean landscape?

Location: 1600‐1900 m a.s.l. in the Sierra Nevada National Park, southern Spain. The landscape is a mosaic composed of native forest and two degraded landscape units: reforestation stands and shrubland.

Methods: We evaluated fruit production, seed rain, seedling emergence and seedling survival in two consecutive years with contrasting rainfall patterns. Seed and seedling data were used to calculate values of seed and establishment limitation.

Results: In general, the woody community was both severely seed‐ and establishment‐limited. Species were less seed‐limited in the landscape units with higher adult density (i.e. shrub species in shrubland, Pinus spp. in reforestation stands). In contrast, degradation did not exacerbate establishment limitation, which was severe in all landscape units. This general pattern was modulated by the biogeographical distribution, dispersal type, and life form of the species. Boreo‐alpine species were more limited in establishment than species with a typical Mediterranean distribution. Zoochorous species were less seed‐limited in the landscape units preferred by dispersers (i.e. native forest). Tree species were more establishment‐limited than shrub species, irrespective of the landscape unit. Seed limitation, and especially establishment limitation, varied among years, with establishment being almost nil in the very dry year.

Conclusion: In the case of Mediterranean landscapes, when degradation from human impact involves a reduction in the adult abundance of the woody plant community (trees and shrubs), seed limitation increases, although establishment limitation is generally high in all landscape units, especially for boreo‐alpine species. Conservation and restoration strategies should take into account our results showing that tree species were unable to recruit in an extremely dry year, because more aridity is expected under a climatic change scenario in Mediterranean ecosystems.
Post‐fire shrub recruitment in a semi‐arid grassland: the role of microsites
Authors: Franzese Jorgelina , Ghermandi Luciana , Donaldo Bran
Published: March 2009

Question: (1) Which factors regulate post‐fire recruitment and spread of the shrub Senecio bracteolatus in Patagonian grasslands? (2) What is the role of the grass Stipa speciosa on S. bracteolatus establishment in the post‐fire succession?

Location: Northwest Patagonia, Argentina.

Methods: We studied the effect of fire on S. bracteolatus recruitment and density by comparing these variables between burned and unburned grasslands. In burned areas, we compared abiotic characteristics and seedling establishment under the canopy of grasses (S. speciosa) and in gaps (inter‐tussock areas). Post‐fire interactions between S. bracteolatus seedlings and S. speciosa were studied using field and greenhouse experiments.

Results: Density of S. bracteolatus was higher in burned than in unburned areas. In burned sites, seedlings were more abundant under tussock grasses, whereas juveniles were more abundant in gaps. Tussocks generated more attenuated micro‐environmental conditions than gaps during stressful summers. Gaps were more abundant in burned sites, while “under tussock” microsites were more frequent in unburned sites. In burned areas, tussocks allowed higher establishment of seedlings (facilitation), but gaps allowed more seedling growth and higher persistence of juveniles.

Conclusions: Fire promoted S. bracteolatus recruitment in Patagonian grasslands by increasing the availability of favourable gap microsites. Grass protection for shrub seedlings became negative with time, probably due to competition with grasses. Gaps led to better performance and persistence of shrub plants. Six years after fire, higher shrub recruitment and adult density (observed as a trend) in burned grassland provides an opportunity for potential S. bracteolatus invasion.
How do trees die? Mode of death in northern Amazonia
Authors: Chao Kuo‐Jung , Phillips Oliver L. , Monteagudo Abel , Torres‐Lezama Armando , Vásquez Martínez Rodolfo
Published: March 2009

Question: How do trees die in high‐mortality and low‐mortality Amazonian forest regions? Why do trees die in different ways?

Location: Humid, lowland forests in Amazonian Peru and Venezuela.

Methods: Patterns of multiple treefall and mode of death (standing, broken or uprooted) were recorded for trees ≥10 cm in diameter in permanent plots. Logistic regression was used to relate mode of death to tree diameter, relative growth rate and wood density.

Results: Frequency of multiple death events was higher in high‐mortality northwestern (NW) than in low‐mortality northeastern (NE) Amazonia, but these events were small, averaging two trees killed per multiple death event. Breakage was the dominant known mode of death (51±8%) in the NW, with half of fatal breakages caused by other treefalls or breakages. Small and slow‐growing trees were more prone to breaking than uprooting. In NE Amazonia, the dominant known mode of death was standing (48±10%); these trees tended to be relatively large and slow growing. Broken trees in NE forests have a lower wood density than uprooted trees.

Conclusions: The major mortality mechanisms differ in the two regions. In the NW it involves an interaction between physiological failure and mechanical failure (small size, slow growth and broken mode). In the NE it is mainly driven by physiological failure (large size, slow growth and standing mode). We propose that by creating different‐sized gaps the different dominant modes of death would favour species from different functional groups and so help to maintain the contrasting functional composition and mortality rates of the two regions.
Building a program of research
Authors: HOLZEMER William L.
Published: March 2009

This article provides highlights of a talk titled, “Building a Program of Research,” given at the Japan Academy of Nursing Science's 28th annual meeting, Fukuoka, Japan, on 13 December 2008. A program of research is defined as a coherent expression of a researcher's area of interest that has public health significance, builds from the published research literature in the field, has relevance for clinical nursing practice, and captures the passion and commitment of the researcher. The Outcomes Model for Health Care Research is proposed as a framework for how to develop and articulate a program of research. Eight steps are proposed to help a new researcher to think about how to build a program of research.
Schizophrenia Modifying the Expression of Gender Identity Disorder
Authors: Baltieri Danilo Antonio , De Andrade Arthur Guerra
Published: March 2009

Introduction

According to the Brazilian Federal Medical Association, transsexualism is recognized as a gender identity disorder if a long-term diagnostic therapeutic process has demonstrated that the transposition of gender roles is irreversible, and if only hormonal and surgical procedures are appropriate to relieve the stress associated with the gender identity. Although such treatment will only be initiated with caution and after a long phase of intense diagnostic screening, the differentiation between pure identity disorders and transsexual feelings secondary to an ongoing psychopathologic process, such as schizophrenia, can be arduous for many health professionals.

Aim

To report a case of a female patient with schizophrenia and transsexualism and the risks of a potential diagnostic confusion.

Method

A 19-year-old black woman, with an 8-year history of undifferentiated schizophrenia and intense gender dysphoria, was referred for sex reassignment surgery evaluation in the Ambulatory for the Treatment of Sexual Disorders of the ABC Medical School.

Result

After a more adequate antipsychotic treatment, her masculine behavior has persisted, but her desire to change her own genital organs has decreased.

Conclusion

A better acceptance of the multiplicity of possible genders should neither contribute to inadequate interpretations of the signs and symptoms of our patients nor facilitate dangerous clinical or surgical recommendations.
The Social Context for Psychological Distress from Iatrogenic Gynecomastia with Suggestions for its Management
Authors: Wassersug Richard J. , Oliffe John L.
Published: March 2009

Introduction

Gynecomastia (breast development in males) is a side effect of androgen deprivation therapy (ADT) for prostate cancer (PCa). Medical interventions to prevent or treat gynecomastia carry risk of additional detrimental side effects. However, untreated gynecomastia can be physically uncomfortable and psychologically distressing. Shame from gynecomastia can lead patients to stop otherwise beneficial exercise.

Aims

Our first aim is to explore the social context for gynecomastia and how it is interpreted by men with the condition, as well as by others, both male and female. Subsequently, we use our understanding of why gynecomastia is psychologically distressing to propose psychosocial interventions that could help men accept this side effect of ADT.

Methods

We draw on academic literature, media accounts, and web-based testimonials from men with gynecomastia, to understand how gynecomastia is perceived by both patients and the medical community. We examine these resources in light of gynecomastia’s impact on sex roles, sexuality, and gender identity issues.

Main Outcome Measures

By exploring what breasts in a male mean to the individual, we produce an understanding of the social context for distress from gynecomastia. From this understanding, we derive hypotheses about who might be most distressed from gynecomastia and strategies for alleviating this distress.

Results

The shame and stigma of gynecomastia is linked to the objectification of women. We suggest that men fear that their breasts will marginalize and subordinate them within gender hierarchies. There is little evidence that breasts on a male erotically attract either men or women. Novel options for living with gynecomastia are contrasted with medicalized strategies including mastectomy.

Conclusion

Assessment instruments need to be developed to identify patients most likely to experience distress from gynecomastia and seek out medical interventions. Surgical, radiological, or pharmacological interventions may not be universally necessary if greater acceptance of gynecomastia is made available through psychosocial support programs. For example, PCa patients may learn to accept gynecomastia through reconceptualizing their breasts as autoerotic. Support programs modeled on those of the breast cancer community, including Encore and dragon boat racing, may also help to build communities to serve patients with gynecomastia while defending individuals against shame, isolation, and loss of self-esteem.
Climate Change Enhances the Potential Impact of Infectious Disease and Harvest on Tropical Waterfowl
Authors: Traill Lochran W. , Bradshaw Corey J. A. , Field Hume E. , Brook Barry W.
Published: March 2009

Global warming exacerbates threats to biodiversity as ecological systems shift in response to altered climatic conditions. Yet the long‐term survival of populations at direct risk from climate change may also be undermined by local factors such as infectious disease or anthropogenic harvest, which leave smaller and more isolated populations increasingly vulnerable to the rapid pace of global change. We review current and future threats to an exemplar tropical waterfowl species, magpie geeseAnseranas semipalmata, and focus on the potential synergies between infectious diseases, harvest, and climate change. We outline viral, bacterial, and fungal pathogens likely to cause disease in geese, and give mention to parasites. Further, we elaborate on a previously developed, spatially explicit population viability model to simulate demographic responses to hunting and novel or enhanced disease outbreaks due to climate change. With no harvest, the simulated disease epizootics only threatened metapopulation viability when both mortality rate was high and outbreaks were regular (a threshold response). However, when contemporary site‐specific harvest is included as an additive impact, the response to disease severity and probability was linear. We recommend field research to test these hypotheses linking drivers of waterfowl population decline to disease–climate change interactions.
Forest Elephants: Tree Planters of the Congo
Authors: Blake Stephen , Deem Sharon Lynn , Mossimbo Eric , Maisels Fiona , Walsh Peter
Published: March 2009

The abundance of large vertebrates is rapidly declining, particularly in the tropics where over‐hunting has left many forests structurally intact but devoid of large animals. An urgent question then, is whether these ‘empty’ forests can sustain their biodiversity without large vertebrates. Here we examine the role of forest elephant (Loxodonta africana cyclotis) seed dispersal in maintaining the community structure of trees in the Ndoki Forest, northern Congo. Analysis of 855 elephant dung piles suggested that forest elephants disperse more intact seeds than any other species or genus of large vertebrate in African forests, while GPS telemetry data showed that forest elephants regularly disperse seeds over unprecedented distances compared to other dispersers. Our analysis of the spatial distribution of trees from a sample of 5667 individuals showed that dispersal mechanism was tightly correlated with the scale of spatial aggregation. Increasing amounts of elephant seed dispersal was associated with decreasing aggregation. At distances of<200 m, trees whose seeds are dispersed only by elephants were less aggregated than the random expectation, suggesting Janzen–Connell effects on seed/seedling mortality. At the landscape scale, seed dispersal mode predicted the rate at which local tree community similarity decayed in space. Our results suggest that the loss of forest elephants (and other large‐bodied dispersers) may lead to a wave of recruitment failure among animal‐dispersed tree species, and favor regeneration of the species‐poor abiotically dispersed guild of trees.
INNOVATION IN LOGISTICS OUTSOURCING RELATIONSHIPS: PROACTIVE IMPROVEMENT BY LOGISTICS SERVICE PROVIDERS AS A DRIVER OF CUSTOMER LOYALTY
Authors: WALLENBURG CARL MARCUS
Published: March 2009

Flint, Larsson, Gammelgaard and Mentzer (2005) and Wagner (2008) emphasize that innovativeness may help logistics service providers (LSPs) differentiate themselves from their competitors. Within the domain of innovation, relationship‐specific proactive improvement by LSPs may play a vital role because in logistics outsourcing relationships, the problem of ex post adaptation exists (Rindfleisch and Heide 1997). So far, however, it remains unclear to what extent LSPs may utilize their proactive improvement to create customer loyalty and whether a focus on either cost or performance improvements is preferable. The present study analyzes 298 logistics outsourcing relationships using a survey method and structural equation modeling to assess the effect that proactive cost improvement and proactive performance improvement have on customer loyalty. Additionally, the moderating effects of “service complexity” and “length of contracting period” on the base effects are analyzed. The results reveal that proactive cost improvement and proactive performance improvement are both strong drivers of all core dimensions of loyalty (retention, extension, and referrals). However, this finding is a composition of two different patterns. Cost improvement, and thus efficiency is the main driver of customer loyalty when the outsourced services are simple and the contracting period relatively short. A clear shift of importance is observable when services increase in complexity and the contracting period lengthens. In such settings, customer loyalty is primarily driven by proactive performance improvement and thus, effectiveness, while cost improvement plays a subordinate role.
ON SOCIAL NETWORK ANALYSIS IN A SUPPLY CHAIN CONTEXT*
Authors: BORGATTI STEPHEN P. , LI XUN
Published: March 2009

The network perspective is rapidly becoming a lingua franca across virtually all of the sciences from anthropology to physics. In this paper, we provide supply chain researchers with an overview of social network analysis, covering both specific concepts (such as structural holes or betweenness centrality) and the generic explanatory mechanisms that network theorists often invoke to relate network variables to outcomes of interest. One reason for discussing mechanisms is to facilitate appropriate translation and context‐specific modification of concepts rather than blind copying. We have also taken care to apply network concepts to both “hard” types of ties (e.g., materials and money flows) and “soft” types of ties (e.g., friendships and sharing‐of‐information), as both are crucial (and mutually embedded) in the supply chain context. Another aim of the review is to point to areas in other fields that we think are particularly suitable for supply chain management (SCM) to draw network concepts from, such as sociology, ecology, input–output research and even the study of romantic networks. We believe the portability of many network concepts provides a potential for unifying many fields, and a consequence of this for SCM may be to decrease the distance between SCM and other branches of management science.
Current Advances in the Cognitive Neuroscience of Music
Authors: Levitin Daniel J. , Tirovolas Anna K.
Published: March 2009

The study of music perception and cognition is one of the oldest topics in experimental psychology. The last 20 years have seen an increased interest in understanding the functional neuroanatomy of music processing in humans, using a variety of technologies including fMRI, PET, ERP, MEG, and lesion studies. We review current findings in the context of a rich intellectual history of research, organized by the cognitive systems underlying different aspects of human musical behavior. We pay special attention to the perception of components of musical processing, musical structure, laterality effects, cultural issues, links between music and movement, emotional processing, expertise, and the amusias. Current trends are noted, such as the increased interest in evolutionary origins of music and comparisons of music and language. The review serves to demonstrate the important role that music can play in informing broad theories of higher order cognitive processes such as music in humans.
The Social Neuroscience of Empathy
Authors: Singer Tania , Lamm Claus
Published: March 2009

The phenomenon of empathy entails the ability to share the affective experiences of others. In recent years social neuroscience made considerable progress in revealing the mechanisms that enable a person to feel what another is feeling. The present review provides an in‐depth and critical discussion of these findings. Consistent evidence shows that sharing the emotions of others is associated with activation in neural structures that are also active during the first‐hand experience of that emotion. Part of the neural activation shared between self‐ and other‐related experiences seems to be rather automatically activated. However, recent studies also show that empathy is a highly flexible phenomenon, and that vicarious responses are malleable with respect to a number of factors—such as contextual appraisal, the interpersonal relationship between empathizer and other, or the perspective adopted during observation of the other. Future investigations are needed to provide more detailed insights into these factors and their neural underpinnings. Questions such as whether individual differences in empathy can be explained by stable personality traits, whether we can train ourselves to be more empathic, and how empathy relates to prosocial behavior are of utmost relevance for both science and society.