bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of body size, temperature, and salinity on the routine metabolism of larval and juvenile spotted seatrout
Authors: Wuenschel M. J. , Werner R. G. , Hoss D. E.
Published: March 2004

Routine oxygen consumption rates of young spotted seatrout Cynoscion nebulosus(Sciaenidae) were measured over a range of temperatures (24, 28, 30 and 32° C) and salinities (5, 10, 20, 35 and 45). Larvae and juveniles, 4·1–39·5 mm standard length (LS), ranging several orders of magnitude in dry body mass were used to estimate the mass–metabolism relationship. Oxygen consumption (μl O2 larva−1 h−1) scaled isometrically with body mass for larvae <5·8 mm LS(phase I, slope = 1·04) and allometrically thereafter (phase II, slope = 0·78). The inflection in the mass–metabolism relationship coincided with the formation of the hypural plate and an increase in the relative tail size of larvae. Salinity did not have a significant effect on routine metabolism during phase I. Temperature and salinity significantly affected routine metabolism during phase II of the mass–metabolism relationship. The effect of salinity was temperature dependent, and was significant only at 30° C. Response surfaces describing the environmental influences on routine metabolism were developed to provide a bioenergetic basis for modelling environmental constraints on growth.
Phenotypic variation among populations of Atherinops affinis(Atherinopsidae) with insights from a geometric morphometric analysis
Authors: O'Reilly K. M. , Horn M. H.
Published: March 2004

Morphological character variation was examined in Atherinops affinis, a temperate marine silverside with a broad geographic range and presumed limited powers of dispersal. Populations of this species were sampled from three California mainland sites, one Channel Island site and one site in the upper Gulf of California. A geometric morphometric analysis yielded higher resolution in the assessment of phenotypic divergence among the four Pacific coast populations than either body measurement or meristic analysis, and it showed that most of the shape variation among these populations occurs in the head region and body depth of the fish. All three analyses supported the hypothesis that populations of A. affinis from central and southern California coastal waters and from Santa Catalina Island are morphologically distinct from each other; the Santa Catalina Island population was found to be the most divergent. On the basis of meristic characters alone, the population of A. affinis from the upper Gulf of California was different from A. affinis populations along the Pacific coast of California. The analyses revealed variation in several morphological characters, e.g. body depth and meristics, known to vary in association with environmental conditions. Given that A. affinis appears to have low among‐population genetic variation, this species may be phenotypically plastic in response to the environmental conditions of the habitat of each population.
Influence of salinity, competition and food supply on the growth of Gobiosoma robustum and Microgobius gulosus from Florida Bay, U. S. A.
Authors: Schofield P. J.
Published: March 2004

The code Gobiosoma robustum and clown Microgobius gulosus gobies were grown in the laboratory over 27 days at two salinities (5 and 35), two food levels [low (a fixed proportion of initial mass) and high (saturation)] and both with and without the presence of the other species. Both species exhibited greatest growth at the high food level and the low (5) salinity. Neither species was affected by the presence of the other species, and there were no overall differences in growth between the two species. Thus, the observed competitive superiority of G. robustum over M. gulosus does not seem to confer an advantage relative to feeding success. Furthermore, as growth of G. robustum was greater at the lower salinity, it is clear that some factor other than salinity is restricting this species from north‐eastern Florida Bay. Additional work on the importance of predation and food resources in various regions of Florida Bay is needed to further evaluate the underlying mechanisms responsible for the bay‐wide distribution of these species.
Biochemical, histological and behavioural aspects of visual function during early development of rainbow trout
Authors: Carvalho P. S. M. , Noltie D. B. , Tillitt D. E.
Published: March 2004

Retinal structure and concentration of retinoids involved in phototransduction changed during early development of rainbow trout Oncorhynchus mykiss, correlating with improvements in visual function. A test chamber was used to evaluate the presence of optokinetic or optomotor responses and to assess the functionality of the integrated cellular, physiological and biochemical components of the visual system. The results indicated that in rainbow trout optomotor responses start at 10 days post‐hatch, and demonstrated for the first time that increases in acuity, sensitivity to low light as well as in motion detection abilities occur from this stage until exogenous feeding starts. The structure of retinal cells such as cone ellipsoids increased in length as photopic visual acuity improved, and rod densities increased concurrently with improvements in scotopic thresholds (2·2 log10 units). An increase in the concentrations of the chromophore all‐trans‐retinal correlated with improvements of all behavioural measures of visual function during the same developmental phase.
Insectivore to frugivore: ontogenetic changes in gut morphology and digestive enzyme activity in the characid fishBrycon guatemalensisfrom Costa Rican rain forest streams
Authors: Drewe K. E. , Horn M. H. , Dickson K. A. , Gawlicka A.
Published: March 2004

Brycon guatemalensis, a Neotropical characid fish, consumes an entirely terrestrial diet, shifting from eating insects as juveniles to fruits and leaves as adults. Juvenile and larger‐sized fish collected in the Rio Puerto Viejo at the La Selva Biological Station in Costa Rica were studied to test the hypotheses that, with ontogeny, (1) relative gut length increases, (2) pyloric caeca arrangement and number remain unchanged and (3) pepsin, trypsin and lipase activities decrease, while α‐amylase activity increases. These hypotheses were mainly supported in that larger fish had longer guts, unchanged pyloric caeca arrangement but fewer caeca, and, at both environmental and standard temperatures for the enzyme assays, lower pepsin and trypsin activities but higher α‐amylase activities than the juveniles. Only lipase, among the digestive enzymes, exhibited the unexpected outcome of either not differing significantly in activity (per g of tissue) between juveniles and larger fish or being significantly higher (per mg of protein) in larger fish. The overall results support the view thatB. guatemalensisis specialized morphologically and biochemically to function first as a carnivore and then as a herbivore during its life history.
The effect of exercise and captivity on energy partitioning, reproductive maturation and fertilization success in adult sockeye salmon
Authors: Patterson D. A. , Macdonald J. S. , Hinch S. G. , Healey M. C. , Farrell A. P.
Published: March 2004

Releasing a population of adult Fraser River sockeye salmon Oncorhynchus nerka from an energetically more expensive non‐feeding natural migration (1089 km, natal groups) and allowing them to sexually mature in either a moderate flow (captive exercise group) or a no flow (captive non‐exercise group) environment resulted in significant differences in body energy densities (MJ kg−1) among groups (ranked: initial natural migrator > non‐exercise > exercise > natal arrivals). Similarly, per cent body lipids were significantly lower in exercise females compared with non‐exercise females, experimentally confirming the central role lipid catabolism has in powering swimming. Although restricting exercise did result in greater body energy reserves at spawning, this did not result in a reallocation of energy to reproduction, as fecundity, egg size and gonad composition were unchanged among the groups. Furthermore, non‐exercise females had delayed maturity, lower egg deposition rates, and were more likely to die prior to egg ovulation than exercise females and natal spawners. Eggs from captive exercise adult females were more likely to survive to the eyed stage than eggs from captive non‐exercise females, but both captive groups had significantly lower egg fertilization success than natal spawners suggesting that confinement stress played a role in some of results presented. There were no significant differences in plasma levels of glucose, lactate, cortisol and reproductive hormones among the groups, but correlations among acute and chronic indicators of stress were significant among individuals. These results indicate that exercise during the late stages of maturation, as might occur normally, may be required for optimizing reproductive maturation and maximizing reproductive success.
Characterization of a novel fibroblast‐like cell line from rainbow trout and responses to sublethal anoxia
Authors: Ossum C. G. , Hoffmann E. K. , Vijayan M. M. , Holt S. E. , Bols N. C.
Published: March 2004

A novel fibroblast‐like cell line RTHDF was established from hypodermal connective tissue of rainbow trout Oncorhynchus mykiss and telomerase activity was demonstrated early and late in cell line development. When RTHDF cells were exposed to bioenergetic stress, i.e. anoxia, activation of the stress activated member of the mitogen‐activated protein kinase family, p38MAPK and induction of heat shock protein (Hsp70) were evident. The time‐course of the p38MAPK activation and the induction of Hsp70 expression in RTHDF were studied in response to chemically induced anoxia. p38MAPK was activated rapidly, with maximal activity after 10 min of anoxia. Hsp70 was induced after 30 min of anoxia, followed by overnight recovery in growth medium at 21° C. Using the p38MAPK‐specific inhibitor SB203580, the enhanced expression of Hsp70 occurred independently of p38MAPK activation in RTHDF. These data suggests that RTHDF can be useful in studying biochemical responses of teleost cells to environmental stress.
CARDIOVASCULAR EFFECTS OF THE ESSENTIAL OIL OF OCIMUM GRATISSIMUM LEAVES IN RATS: ROLE OF THE AUTONOMIC NERVOUS SYSTEM
Authors: Lahlou Saad , Interaminense Leylliane de Fátima Leal , Leal‐Cardoso José Henrique , Morais Selene Maia , Duarte Gloria Pinto
Published: March 2004

1. The cardiovascular effects of intravenous (i.v.) administration of the essential oil of Ocimum gratissimum (EOOG) were investigated in rats. In addition, the present study examined: (i) whether the autonomic nervous system is involved in the mediation of EOOG‐induced changes in mean aortic pressure (MAP) and heart rate (HR); and (ii) whether these changes could be attributed, at least in part, to the actions of eugenol, the major constituent of EOOG.

2. In both pentobarbitone‐anaesthetized and conscious rats, i.v. bolus injections of EOOG (1–20 mg/kg) elicited immediate and dose‐dependent decreases in MAP and HR. These responses to EOOG were of the same order of magnitude irrespective of whether the animal was under general anaesthesia.

3. Pretreatment of anaesthetized rats with bilateral vagotomy did not significantly modify the EOOG‐induced dose‐dependent hypotension, whereas it significantly reduced the bradycardia at the highest dose used.

4. In conscious rats, i.v. injections of bolus doses (1–10 mg/kg) of eugenol also elicited immediate and dose‐dependent decreases in MAP and HR. Intravenous pretreatment of conscious rats with either methylatropine (1 mg/kg) or hexamethonium (30 mg/kg) significantly reduced the EOOG‐induced dose‐dependent bradycardia without affecting the hypotension.

5. These data show, for the first time, that i.v. administration of EOOG to either anaesthetized or conscious rats induces an immediate and significant hypotension and bradycardia, which appear to be due, at least in part, to the actions of the major constituent of EOOG, eugenol. These cardiovascular effects appear to be mediated by different pathways because only EOOG‐induced hypotension appears to be independent of the presence of an operational autonomic nervous system. This may suggest that the hypotensive activity of EOOG results from its vasodilatory effects directly upon vascular smooth muscle.
NITRIC OXIDE INHIBITION ACCELERATES HYPERTENSION AND INDUCES PERIVASCULAR INFLAMMATION IN RATS
Authors: Hsieh Nan‐Kuang , Wang Jia‐Yi , Liu Jiang‐Chuan , Wang Shwun‐De , Chen Hsing I
Published: March 2004

1. Inflammatory changes in peripheral arteries have been reported in animal models of hypertension. Whether they occur in cerebral arteries (CA) with hypertension induced by deprivation of endogenous nitric oxide (NO) remains unknown.

2. In the present study, we compared the arteriolar injury score (AIS) and perivascular inflammation in CA between hypertensive and normotensive rats following NO deprivation with the NO synthase inhibitor Nω‐nitro‐l‐arginine methyl ester (l‐NAME). Five‐week‐old male spontaneously hypertensive rats (SHR) and Wistar ‐Kyoto (WKY) rats were fed with l‐NAME (1 mg/mL) for 4 weeks.

3. Nitric oxide deprivation resulted in time‐dependent elevations in tail‐cuff pressure (representing systolic blood pressure (SBP)) in both SHR and WKY rats. The magnitude of increase in SBP was larger in SHR (+81.0 ± 3.2 vs+25.0 ± 2.2 mmHg; P < 0.01). Arteriolar hyalinosis and AIS in various segments of the CA were assessed with periodic acid‐Schiff staining and inflammatory cells were immunostained with the antibody against macrophage/monocyte marker (ED1). The ED1+ cells appeared in the middle CA of l‐NAME‐treated SHR as early as 2 weeks after treatment. These cells were not observed in l‐NAME‐treated WKY rats and untreated SHR. More ED1+ cells were found in l‐NAME‐treated SHR than l‐NAME‐treated WKY rats after 4 weeks treatment.

4. The AIS and number of ED1+ cells around the perivascular area of the internal carotid artery were significantly higher in l‐NAME‐treated compared with untreated rats (AIS: 137 ± 28 vs 46 ± 10 for WKY rats, respectively; 169 ± 18 vs 53 ± 6 for SHR, respectively (P < 0.01); ED1+ cells: 7.9 ± 0.6 vs 1.3 ± 0.9 for WKY rats, respectively; 13.6 ± 2.7 vs 2.1 ± 0.9 for SHR, respectively (P < 0.01)), although SBP was higher in untreated SHR than in l‐NAME‐treated WKY rats (170 ± 4 vs 137 ± 4 mmHg, respectively; P < 0.05).

5. These findings suggest that ED1+ cells appeared in the middle CA of l‐NAME‐SHR as early as 2 weeks after treatment. Chronic inhibition of NO accelerates hypertension and induces perivascular inflammation.
Indomethacin decreases particulate guanylyl cyclase activity in rat kidney
Authors: Lee JongUn , Kim Soo Wan , Jung Tack‐Kyoon , Oh YoonWha , Park Choon Soon , Ma Seong Kwon , Kim Nam Ho , Choi Ki Chul
Published: March 2004

1. Effects of non‐steroidal anti‐inflammatory drugs on the local atrial natriuretic peptide (ANP) and nitric oxide (NO) systems in the kidney were investigated.

2. Male Sprague‐Dawley rats were treated with indomethacin (5 mg/kg, every 12 h, i.p.) for 2 days. The expression of ANP and natriuretic peptide receptor‐A (NPR‐A) mRNA was determined in the kidney, as was that of endothelial NO synthase (NOS) proteins. Particulate and soluble guanylyl cyclase activities were determined separately.

3. Following treatment with indomethacin, urinary sodium excretion decreased significantly. Although the renal expression of ANP was not changed significantly, that of NPR‐A decreased significantly. The expression of NOS increased significantly. Particulate guanylyl cyclase activity was decreased, whereas the activity of soluble guanylyl cyclase was increased. The catalytic activity of Na+/K+‐ATPase was increased, with no significant changes in its expression. The expression of the type 3 Na/H exchanger and Na–K−2CL cotransporters increased significantly.

4. The indomethacin‐induced decrease in urinary sodium excretion may be attributed, at least in part, to decreased activity of the local ANP/cGMP system. The increased activity of the NO/cGMP system may be a compensatory response to the diminished activity of the prostaglandin system.
RESTING METABOLIC RATE AND POST‐PRANDIAL THERMOGENESIS BY LEVEL OF AEROBIC POWER IN OLDER ATHLETES
Authors: Sullo Alessio , Cardinale Pasquale , Brizzi Guglielmo , Fabbri Bruno , Maffulli Nicola
Published: March 2004

1. The aim of the present study was to evaluate the resting metabolic rate (RMR) and thermogenic effect of a meal (TEM) in older athletes.

2. Eighteen older male volunteers were divided into three groups according to their aerobic power related to fat‐free mass (FFM) as follows: (i) group I, high aerobic power (Vo2max > 70 mL/kg FFM per min); (ii) group II, moderate aerobic power (Vo2max = 55–70 mL/kg FFM per min); and (iii) group III, low aerobic power (Vo2max < 55 mL/kg FFM per min).

3. The RMR values, covariated for FFM using analysis of covariance (ancova), were higher in group I (mean (±SEM) 1.09 ± 0.04 kcal/min) than in groups II and III (0.99 ± 0.05 and 0.91 ± 0.03 kcal/min, respectively). Group I had a tendency for higher mean TEM values compared with the other groups, but the differences were not statistically significant for absolute or percentage values.

4. Master endurance athletes with high aerobic power exhibit a higher RMR than master endurance athletes of similar age and body composition but with lower aerobic power.
EFFECT OF HIGH‐SALT DIET OR CHRONIC CAPTOPRIL TREATMENT ON EXERCISE CAPACITY IN NORMOTENSIVE RATS
Authors: Minami Naoyoshi , Mori Nobuyoshi , Nagasaka Makoto , Harada Taku , Kurosawa Hajime , Kanazawa Masayuki , Kohzuki Masahiro
Published: March 2004

1. We investigated whether chronic suppression of the renin–angiotensin system, which is known to be associated with reductions in microvascular density and vasodilator responsiveness of skeletal muscle, could affect exercise capacity in normotensive rats.

2. Rats were placed on normal rat chow, normal rat chow with captopril (100 mg/kg per day) or a high‐salt diet (HS; 4%) for 4 weeks. Following these interventions, rats with indwelling carotid artery catheters were submitted to stepwise increasing exercise on a motor treadmill at a speed of 10, 20 and 30 m/min for 4 min while blood lactate was measured.

3. Blood lactate after exercise at a speed of 20 m/min was significantly higher and the duration during which rats were able to run at a speed of 30 m/min was significantly shorter in captopril‐treated rats and rats fed an HS diet compared with control rats.

4. We conclude that chronic treatment with captopril or HS diet could reduce the exercise capacity in inactive normotensive rats, probably through chronic inhibition of the renin–angiotensin system.
A NOVEL WATER‐SOLUBLE VITAMIN E DERIVATIVE PREVENTS ACUTE LUNG INJURY BY BACTERIAL ENDOTOXIN
Authors: Uchiyama Kazuhiko , Takano Hirohisa , Yanagisawa Rie , Inoue Ken‐ichiro , Naito Yuji , Yoshida Norimasa , Yoshino Shin , Murase Hironobu , Ichinose Takamichi , Yoshikawa Toshikazu
Published: March 2004

1. Various chemokines, such as keratinocyte chemoattractant (KC), macrophage inflammatory protein (MIP)‐1α and macrophage chemoattractant protein (MCP)‐1, are involved in the pathogenesis of acute lung injury induced by bacterial endotoxin (lipopolysaccharide; LPS). Oxidative stress is an important regulator of the expression of these chemokines, whereas vitamin E protects against LPS‐induced insults. In the present study, we determined the effects of 2‐(α‐d‐glucopyranosyl) methyl‐2,5,7,8‐tetramethylchroman‐6‐ol (TMG), a novel water‐soluble vitamin E derivative with excellent anti‐oxidant activity, on acute lung injury induced by intratracheal instillation of LPS (125 µg/kg) in mice.

2. When TMG was administered intratracheally and intravenously (0.1, 1.0 or 10 mg/kg), it dose‐dependently decreased the infiltration of neutrophils into bronchoalveolar lavage fluid after LPS challenge.

3. Histological examination showed that treatment with TMG ameliorated the LPS‐induced infiltration of neutrophils into the lungs. Furthermore, TMG attenuated the LPS‐induced increase in pulmonary expression of KC, MIP‐1α and MCP‐1 at both the transcriptional and translational levels.

4. These results indicate that TMG is a possible treatment for acute lung injury, especially that caused by Gram‐negative bacteria. The therapeutic effect of TMG may be mediated, at least in part, by suppression of the local expression of chemokines, possibly through its strong anti‐oxidant activity.
EFFECTS OF TAURINE AND HOMOCYSTEINE ON CALCIUM HOMEOSTASIS AND HYDROGEN PEROXIDE AND SUPEROXIDE ANIONS IN RAT MYOCARDIAL MITOCHONDRIA
Authors: Chang Lin , Zhao Jing , Xu Jianxin , Jiang Wei , Tang Chao Shu , Qi Yong Fen
Published: March 2004

1. Taurine and homocysteine are metabolites of methionine. Hyperhomocysteinaemia is one of the risk factors for cardiovascular disease. Although taurine may be a cardiovascular cytoprotective substance, we hypothesized that it may antagonize the effects of homocysteine on myocardial mitochondrial function.

2. We studied the effects of taurine and homocysteine on [45Ca] uptake, Ca2+‐ATPase activity and generation of hydrogen peroxide and superoxide anions in vitro in rat isolated myocardial mitochondria.

3. Results showed that the inhibition of mitochondrial [45Ca] uptake by homocysteine (0.1, 0.5 and 1.0 mmol/L) was concentration dependent. Taurine (5, 10 and 20 mmol/L) promoted [45Ca] uptake in a concentration‐dependent manner, as well as concentration dependently reducing the homocysteine (0.5 mmol/L)‐induced inhibition of mitochondrial [45Ca] uptake.

4. Homocysteine significantly inhibited mitochondrial Ca2+‐ATPase activity, whereas taurine had a diphasic action on this activity. Taurine, at 5 and 10 mmol/L, increased Ca2+‐ATPase activity (P < 0.01), but 20 mmol/L taurine inhibited Ca2+‐ATPase activity (P < 0.05). Taurine attenuated the inhibitory effect of homocysteine on Ca2+‐ATPase activity.

5. Homocysteine stimulated the generation of hydrogen peroxide and superoxide anions. Taurine had no effect on the generation of the anions, but inhibited their homocysteine‐stimulated generation.

6. These results indicate that taurine and homocysteine have opposite effects in myocardial mitochondria with regard to [45Ca] uptake, Ca2+‐ATPase activity and the generation of hydrogen peroxide and superoxide anions. Our results may show an important mechanism for the cardiovascular protective effects of taurine.
HAEMODYNAMIC AND TUBULAR RENAL DYSFUNCTION IN RATS WITH SUSTAINED ARTERIAL CALCINOSIS
Authors: Quaglia Nora B , Brandoni Anabel , Villar Silvina R , Torres Adriana M
Published: March 2004

1. In humans, two of the principal characteristics of vascular ageing are arterial wall calcification and decreased arterial distensibility, which induce organ damage. To amplify arterial calcium accumulation in laboratory animals, it is necessary to use an overdose of vitamin D3.

2. The aim of the present study was to assess the impact of arterial calcium overload on renal function.

3. Adult male Wistar rats were randomly divided into two groups: control and treated rats. Treated rats were injected 10 days before the experiment with a single dose of vitamin D3 (300 000 IU/kg, i.m.).

4. Treated rats showed a decrease in renal blood flow and glomerular filtration rate. Tubular parameters were not modified under basal conditions. In contrast, a statistically significant increase in the fractional excretion of Na, K, Ca and H2O were observed in treated rats after the acute increment of sodium distal delivery, suggesting that the reabsorptive capacity of the thick ascending limb may be altered in treated rats.

5. Thus, Na+/K+‐ATPase activity was evaluated in homogenates from renal cortex and medulla. Rats with arterial calcinosis presented a diminished activity of Na+/K+‐ATPase in medulla homogenates.

6. An increment in the abundance of the Na–K–2Cl cotransporter (NKCC2) was observed in renal medulla homogenates from treated rats. It is suggested that this may compensate for the inefficiency of Na+/K+‐ATPase under basal conditions but, in the presence of acute distal sodium overload, the increment in NKCC2 abundance may not be sufficient to compensate for the decrease in Na+/K+‐ATPase activity.

7. In summary, in our experimental model of arterial calcinosis, renal function is impaired, presenting a vascular compromise and altered function of the medullar thick ascending limb that becomes evident in the presence of acute high distal sodium delivery.
PARTICIPATION OF VASOPRESSIN IN THE DEVELOPMENT OF CEREBRAL VASOSPASM IN A RAT MODEL OF SUBARACHNOID HAEMORRHAGE
Authors: Trandafir Cristina C , Nishihashi Tsuyoshi , Wang Aimin , Murakami Shizuka , Ji Xu , Kurahashi Kazuyoshi
Published: March 2004

1. Previous studies have suggested the involvement of arginine vasopressin (AVP) and inflammation in the development of cerebral vasospasm after subarachnoid haemorrhage (SAH). The aim of the present study was to clarify the role of AVP in the arterial narrowing following cerebral haemorrhage by examining the effect of SR 49059 (a V1 receptor antagonist) on the diameter of rat basilar artery exposed to SAH. The effect of the 5‐lipoxygenase inhibitor ZM 230487 on AVP‐induced contraction of rat basilar arteries was also investigated.

2. After 1 h and 2 days from SAH induction, brains were removed and pictures of the basilar arteries were taken. The external diameter of the basilar artery was measured in the presence and absence of SR 49059 (1 mg/kg, i.v.). For in vitro experiments, the basilar arteries isolated from control and SAH rats (at 1 h and at 2 days from SAH induction) were cut into spiral preparations and the AVP (0.3 nmol/L)‐induced contraction in the presence of ZM 230487 was investigated. Each group analysed (i.e. control, SAH 1 h and SAH 2 days) consisted of eight rats.

3. The diameter of rat basilar arteries decreased by 43 and 25% at 1 h and 2 days from SAH induction, respectively, compared with control. The administration of SR 49059 significantly reduced cerebral vasospasm. After SAH induction, the diameter of the basilar artery in SR 49059‐treated groups decreased by only 22% (at 1 h) and by 3% (at 2 days) compared with the control group (P < 0.01). In basilar arterial strips, ZM 230487 attenuated the vasopressin‐induced contraction in both control and SAH groups. However, SAH groups showed a significant resistance of the AVP‐induced contraction in the presence of ZM 230487 compared with control (P < 0.05).

4. The results suggest that the cerebral vasospasm in SAH rats is due, at least in part, to endogenous AVP and may involve an increase in the activity of 5‐lipoxygenase. SR 49059 may represent a potential therapeutic strategy for the treatment of cerebral vasospasm.
ISCHAEMIA ENHANCES THE ROLE OF CA2+‐ACTIVATED K+ CHANNELS IN ENDOTHELIUM‐DEPENDENT AND NITRIC OXIDE‐MEDIATED DILATATION OF THE RAT HINDQUARTERS VASCULATURE
Authors: Woodman Owen L , Wongsawatkul Orapin
Published: March 2004

1. We compared the effects of the nitric oxide synthase inhibitor NG‐nitro‐l‐arginine (l‐NOARG) and tetraethylammonium (TEA), a blocker of large conductance Ca2+‐activated K+ (BKCa) channels, on vasodilator responses to endothelium‐dependent (acetylcholine; ACh) and ‐independent (sodium nitroprusside; SNP) vasodilators. The mechanism of the vasodilator responses was determined in rat hindquarters under normal conditions (sham ischaemia) and after 2 h ischaemia followed by reperfusion with physiological saline.

2. In sham ischaemia, the responses to ACh were significantly reduced by l‐NOARG (1 mmol/L) and TEA (1 mmol/L) and there was a further reduction in response the presence of both agents. Dilator responses to SNP were significantly enhanced by l‐NOARG, whereas TEA did not alter the SNP‐induced vasodilatation when given either alone or in the presence of l‐NOARG.

3. After ischaemia, l‐NOARG caused a similar inhibition of ACh‐induced dilatation to that observed in sham ischaemia. However, TEA alone or combined with l‐NOARG caused a significantly greater inhibition of the ACh‐induced vasodilatation after ischaemia than observed in the sham ischaemia group. Tetraethylammonium alone did not affect the responses to SNP, but it did attenuate the enhanced dilatation observed in the presence of l‐NOARG.

4. In the rat hindquarters vasculature, both nitric oxide and the opening of TEA‐sensitive K+ channels contribute to ACh‐induced endothelium‐dependent dilatation. In addition, a TEA‐sensitive mechanism was not involved in the SNP‐induced dilatation under normal conditions but, after ischaemia, if there is a further inhibition of endogenous nitric oxide by l‐NOARG, exogenous nitric oxide causes dilatation that is sensitive, in part, to TEA. Thus, the contribution of the opening of BKCa channels to endothelium‐dependent vasodilatation assumes greater importance after ischaemia and reperfusion. This may reflect an increased ability of nitric oxide or cGMP to open BKCa channels after ischaemia.
Confirmation of the presence of Scutigerella immaculata (Newport) in Australia (Symphyla: Scutigerellidae)
Authors: Halliday RB
Published: March 2004

Abstract  The presence of the garden symphylan Scutigerella immaculata in Australia is confirmed on the basis of specimens attacking an asparagus crop in Victoria. This species feeds on the roots of a wide variety of crop plants overseas, and has the potential to become a serious pest in Australia.
Natural incidence of fruit flies with character states intermediate to those of the sibling species Bactrocera tryoni (Froggatt) and B. neohumeralis (Hardy) (Diptera: Tephritidae)
Authors: Pike Nathan
Published: March 2004

Abstract  Naturally occurring flies of intermediate form between Bactrocera tryoni and B. neohumeralis have been known since the 1950s, and their resemblance to laboratory hybrids has been repeatedly noted. It has been demonstrated that although intermediates may be hybrids, these may equally be the consequence of intraspecific variation within either parent species. This paper aims to provide insight into the true nature of field‐collected intermediate flies by assessing their appearance, their mating behaviour and their incidence relative to the abundance of the parent species. Flies were reared from a variety of infested fruit that was collected over an 8 day period from coastal regions of south‐eastern and central Queensland. The vast majority (93%) of the >4000 flies collected were B. tryoni. B. neohumeralis and intermediates, respectively, comprised only 5% and 2% of the population. The callus colour and patterning of intermediates did not change as flies matured. The majority of intermediates tended to have brownish calli and exhibited courtship behaviour during the day. Intercrossing of these intermediates led to a large number of flies that were morphologically identical to B. neohumeralis, although intermediate types did persist throughout the two subsequent generations studied. These data provide circumstantial evidence for the occurrence of interspecific gene flow, particularly in the direction of B. neohumeralis, but do not discount the possibility of a non‐hybrid origin of intermediate flies.
Spider fauna of soybean crops in south‐east Queensland and their potential as predators of Helicoverpa spp. (Lepidoptera: Noctuidae)
Authors: Pearce Sarina , Hebron Wendy M , Raven Robert J , Zalucki Myron P , Hassan Errol
Published: March 2004

Abstract  Spiders are among the most abundant predators recorded in grain crops in Australia. They are voracious predators, and combined with their high abundance, may play an important role in the reduction of pest populations. The significance of spider assemblages as biological control agents of key pests such as Helicoverpa spp. in Australian agroecosystems is largely unknown. A thorough inventory was made of the spider fauna inhabiting unsprayed soybean fields at Gatton, south‐east Queensland. One‐hundred‐and‐two morphospecies from 28 families were collected using vacuum sampling and pitfall traps across two summer seasons (2000–01, 2001–02). No‐choice feeding tests in the laboratory, using eggs and larvae of Helicoverpa armigera (Hübner) as prey, were used to ascertain the predatory potential of each spider group. The field‐collected spider assemblage ate on average 2.4 (±0.7 standard error) to 5.0 (±0.8) eggs per 24 h per spider (10–25% of those available), depending on level of starvation. Clubionidae were the only spiders to readily consume eggs in the laboratory (mean of 18.4 ± 1.5 eggs per starved spider and 8.2 ± 3.9 per non‐starved spider after 24 h). Starved spiders consumed 9.4 (± 0.1) first‐instar larvae per 24 h per spider (90% of those available). This information was combined with field observations and literature from Australian and overseas studies to assess the potential of spider groups as predators of Helicoverpa spp. Lycosidae, Clubionidae, Oxyopidae, Salticidae and Thomisidae have the capacity to contribute to control of Helicoverpa spp.
Parasitism and seasonal phenology of leafblister sawfly, Phylacteophaga froggatti (Hymenoptera: Pergidae), in Eucalyptus globulus plantations in south‐western Australia
Authors: Loch Andrew D , Matthiessen John N , Floyd Rob B
Published: March 2004

Abstract  Parasitism levels and seasonal phenology of the introduced species leafblister sawfly, Phylacteophaga froggatti, in south‐western Australian blue gum (Eucalyptus globulus globulus) plantations were investigated. Leafblister sawfly was found at all times of the year, with overlapping generations. However, it became locally rare or extinct on a frequent but temporary basis at all sampled plantations for unknown reasons. Cirrospilus margiscutellum and Bracon confusus were the only parasitic wasps reared from leafblister sawfly larvae and pupae, with both species occurring at such low levels that they did not have a significant impact on leafblister sawfly populations. The parasitic wasp B. phylacteophagus, successfully used in the biological control of leafblister sawfly elsewhere, was not found. Its absence indicates that the elevated pest status of leafblister sawfly in south‐western Australia may be a result of inadequate biological control, and a ‘classical’ biological control program using B. phylacteophagus is recommended for the pest.
Nesting biology of an Australian resin bee (Megachile sp.; Hymenoptera: Megachilidae): a study using trap nests
Authors: Paini Dean R
Published: March 2004

Abstract  Nesting biology data of an undescribed Megachile sp. (Western Australian Museum number M323/F367) was collected using trap nests placed in the Northern Beekeepers Nature Reserve, Western Australia. Nest construction occurred from October to April with a peak in February, which corresponded to a peak in the number of eggs per nest. Many progeny entered diapause and did not emerge until the beginning of the following season. Four parasitoid species also emerged from nests, three hymenopterans and one dipteran. Nests were clumped at locations within sites and this may have increased progeny survival by the encounter‐dilution effect. Female progeny were heavier and more numerous than males with male progeny always emerging first (protandry). This female‐biased sex ratio may be an example of local resource enhancement as a consequence of nest clustering.
Can economic injury levels be derived for sugarcane weevil borer, Rhabdoscelus obscurus (Boisduval) (Coleoptera: Curculionidae), in far‐northern Queensland?
Authors: Sallam Mohamed N , McAvoy Catherine A , Puglisi Garrad D , Hopkins Alan M
Published: March 2004

Abstract  Split‐cane traps were used to monitor trends in sugarcane weevil borer populations in eight commercial sugarcane fields of far‐northern Queensland during the 2000–02 cane‐growing seasons. Adult borers first appeared in all fields in December–January and numbers increased gradually. Populations declined in most fields in February, followed by another increase during March–April. Trap catches started to decline steadily in early June and were the lowest by harvest time (August–October). Similar population trends were seen in the 2 years. Multiple‐regression analysis showed that borer activity is highly dependent on minimum temperature, with rainfall having no clear impact on borer dynamics. Damaged stalks per hectare and damaged internodes per stalk ranged between 6.3 and 28.6% and 0.15–0.83, respectively, and infestations were associated with losses of commercial cane sugar (CCS) of up to 1.96 units. Numbers of adult borers caught in split‐cane traps during the season were not correlated with the number of damaged stalks or internodes at the end of the season in all cases, and similar borer densities resulted in different damage rates. Hence, calculation of a precise economic injury level is not feasible. Treatment with Regent® (Rhône‐Poulenc Rural, NSW, Australia) (200 g L−1 fipronil at 75 g active ingredient per hectare) would be economical when borer damage exceeded 0.3–0.4 internodes per stalk. This level of damage is not uncommon in many areas of far‐northern Queensland, so insecticidal treatment may be cost effective in areas of high weevil borer infestation.
Introduction: Environmental conflict in the Asia‐Pacific
Authors: Jackson Laurie Skuba , Pradubraj Piyachatr
Published: March 2004

Abstract:  The literature on environmental conflict has expanded greatly over the past 10 years, yet most of the cases and theory have been from a Western, Northern, and developed world context. This volume concentrates on cases of current conflict and its management from Asian and Pacific nations. This paper presents a brief literature review of the nature of environmental conflict and highlights some of the key authors who have featured. Their conclusions are summarised into four key suppositions; a) Environmental conflict is a result of scarcity and represents social struggles against uneven usage and allocation of resources; b) Environmental conflict reflects poor performance by governments in developing complex public policy; c) Environmental conflict involves the issues of power and rights; d) Environmental conflict is an inevitable consequence of development and can be constructive.
On the colonial margins and in the global hotspot: Park–people conflicts in highland Thailand
Authors: Roth Robin
Published: March 2004

Abstract:  Forest resource management in Thailand bears the mark of its historical position on the margins of colonial power and its present position in a biodiversity hotspot. During the colonial era, British forestry in Burma and India had a fundamental influence on the knowledge and techniques used in Thai forest management. More recently, international conservation agendas and organisations have influenced the ways in which the Thai government regulates the forest within its boundaries. The treatment of forests as a national and international resource, defined in interaction with colonial neighbours and global partners, has resulted in legal constructs, spatially simplistic conservation mechanisms and a conception of nature ill‐suited to managing forests as a local resource. This paper investigates the manifestation of Thailand's historical legacy in local park‐people conflicts by drawing on research conducted in a region where the government is establishing a national park. It finds that the continued use of laws, tools and concepts derived from colonial and global influences undermines the forestry department's ability to address the contemporary challenge of managing forests as a local, as well as a national/global, commons.
China's compliance in global environmental affairs
Authors: Chan Gerald
Published: March 2004

Abstract:  As the most populous country on earth with 10 per cent of its rare species of flora and fauna, China's environmental practice is of great importance. Already the country is one of the most polluted places in the world. At least seven out of the ten of the world's most polluted cities are located in China. It is the second largest producer of greenhouse gases after the United States, inflicting heavy, long‐term casualties on its own public health and economic development as well as on those of its close neighbours in the Asia‐Pacific region. How to strike a proper balance between environmental protection and fast economic growth will have an important impact on China's modernisation outcome and its international standing. The country began to pay serious attention to environment problems in the 1970s. Since the adoption of the reform and opening‐up policy in the late 1970s, it has signed or ratified many international treaties dealing with environmental issues. By now, it has entered into most international environmental regimes. But how compliant is China with respect to commitments made to these regimes? How willing and capable is it in complying with international environmental norms and rules? What does sustainable development mean to China? How do red tape, fear, inexperience, and ignorance affect China's efforts to protect its environment? And how do inter‐ministerial wrangling and the growth of green NGOs within China affect its compliance? This paper tries to answer these questions.
An appraisal of environmental conflict management provisions in New Zealand's Resource Management Act 1991
Authors: Montgomery Roy L. , Kidd Jonathan A.H.
Published: March 2004

Abstract:  Since the 1970s a body of literature has developed internationally which can be termed loosely as ‘environmental conflict management’ (ECM) theory and practice. When New Zealand's disparate environmental management framework was reformed during the 1980s a ‘superstatute’ known as the Resource Management Act (RMA), passed in 1991, was the major outcome. During the RMA policy formulation process in the late 1980s, known as Resource Management Law Reform (RMLR), calls were made for better integration of mediation and other alternative dispute resolution (ADR) approaches into the statutory framework. The final wording of the RMA includes specific clauses on mediation and the option of ‘pre‐hearing meetings’, suggesting that ECM and environmental dispute resolution (EDR) approaches have become part of the new decision‐making framework in New Zealand. Given such provisions, and the fact that it is now more than ten years since the RMA was passed, an appraisal of ECM/EDR progress to date within this statute seems justified. It is argued that to date very little emphasis has been placed upon early EDR intervention. This lack of emphasis, it is concluded, is due primarily to low levels of awareness and inadequate training and despite limitations on its usefulness in certain resource conflict settings we suggest that there is scope for greater promotion and implementation of EDR approaches in the local government context.
The Significance of Students: Can Increasing “Student Voice” in Schools Lead to Gains in Youth Development?
Authors: Mitra Dana L.
Published: March 2004

The notion of “student voice,” or a student role in the decision making and change efforts of schools, has emerged in the new millennium as a potential strategy for improving the success of school reform efforts. Yet few studies have examined this construct either theoretically or empirically. Grounded in a sociocultural perspective, this article provides some of the first empirical data on youth participation in student voice efforts by identifying how student voice opportunities appear to contribute to “youth development” outcomes in young people. The article finds that student voice activities can create meaningful experiences for youth that help to meet fundamental developmental needs—especially for students who otherwise do not find meaning in their school experiences. Specifically, this research finds a marked consistency in the growth of agency, belonging and competence—three assets that are central to youth development. While these outcomes were consistent across the students in this study, the data demonstrate how the structure of student voice efforts and nature of adult/student relations fundamentally influence the forms of youth development outcomes that emerge.
The Communication Requirements of Democratic Schools: Parent-Teacher Perspectives on Their Relationships
Authors: Miretzky Debra
Published: March 2004

Research on parent-teacher relationships tends to relegate parents to visitor roles in schools and to reinforce student achievement as the primary goal of parent-teacher relationships. This article argues for the recognition of the importance of talk among parents and teachers—both as a research methodology and as a desirable outcome—in creating and sustaining democratic communities that support school improvement. The study described used a qualitative approach that incorporated interviews and focus groups in a participative inquiry. Individual interviews with fourth through eighth grade teachers and parents determined the issues to be explored first in separate and then joint focus groups. Teachers and parents together discussed issues such as defensiveness, communication, and alliances. While parents and teachers did not espouse “democratic communities” per se, the values they expressed as important—investment in the school community, direct and honest communication, trust, mutual respect and mutual goals—all reflect the “communication requirements” of such communities. Parents and teachers may routinely frame the meanings of their encounters in terms of the children they have in common, but it appears that what they look for from each other is clearly connected to what they need for themselves as people who share a community that reflects democratic values.
Short- and Long-Term Differences in Instructional Effectiveness between Intensive and Semester-Length Courses
Authors: Seamon Marc
Published: March 2004

A broad literature base on the instructional effectiveness of intensive and semester-length courses often fails to find significant differences between the formats. Of those studies that do find differences, most suggest that intensive courses are superior. However, many of the studies are theoretically or methodologically flawed, and none examined crucial, long-term differences. This examination of student characteristics and instructional effectiveness in one matched pair of educational psychology classes found that, initially, students in the intensive version of the course performed significantly better than students in the semester-length course on posttests of content and questions tapping higher-order learning. The two groups of students did not differ significantly in their affinity for learning (need for cognition), age or GPA, suggesting the superior performance was the result of the intensive course format and not any pre-existing student characteristics. However, follow-up research duplicating the original study with the same participants three years later failed to find any significant difference between the two formats, suggesting that the initial superiority of the intensive format will fade if not maintained.
TollSim: Simulation and evaluation of toll stations
Authors: Correa E. , Metzner C. , Niño N.
Published: March 2004

This work presents a stochastic simulation model and experimentation for a toll system developed for a highly concurred highway toll in Venezuela, followed by a discussion of performance and economic indicators. Although mathematical models for resource problems have been developed, their use is not widespread, particularly in developing countries were toll systems are manually operated. The main objective of TollSim is to start building an infrastructure and infostructure to be used in a decision support system for management of traffic related issues in a technologically excluded region. The model was developed using an object‐oriented approach and implemented in MODSIM‐III, SIMGRAPHICSII and SIMDRAW.