Being in a crowd bonds people via physiological synchrony.

Collective events can generate intense emotions, shape group identities, and forge strong bonds. Do these effects extend to remote participation, and what are the psychological mechanisms underpinning their social power? We monitored psycho-physiological activity among groups of basketball fans who either attended games in-person (in a stadium) or watched games live on television in small groups. In-person attendance was associated with greater synchronicity in autonomic nervous system activation at the group level, which resulted in more transformative experiences and contributed to stronger identity fusion. Our findings suggest that the social effects of sports depend substantially on the inter-personal dynamics unfolding among fans, rather than being prompted simply by watching the game itself. Given the increasing prevalence of virtual experiences, this has potentially wide-reaching implications for many domains of collective human interaction.

Investigation of combined kV/MV CBCT imaging with a high-DQE MV detector.

PURPOSE: Combined kV-MV cone-beam tomography (CBCT) imaging has been proposed for two potentially important image-guided radiotherapy applications: (a) scan time reduction (STR) and (b) metal artifact reduction (MAR). However, the feasibility of these techniques has been in question due to the low detective quantum efficiencies (DQEs) of commercially available electronic portal imagers (EPIDs). The goal of the work was to test whether a prototype high DQE MV detector can be used to generate acceptable quality pretreatment CBCT images at acceptable dose levels. METHODS: 6MV and 100 kVp projection data were acquired on a Truebeam system (Varian, Palo Alto, CA). The MV data were acquired using a prototype EPID containing two scintillators (a) a standard copper-gadolinium oxysulfide (Cu-GOS) screen having a zero-frequency DQE (DQE(0)) value of 1.4%, and (b) a prototype-focused cadmium tungstate (CWO) pixelated "strip" with a DQE(0) = 22%. The kV data were acquired using the standard onboard imager (DQE(0) = 70%). The angular spacing of the MV projections was 0.81° and the source output was 0.03 MU/projection while the kV projections were acquired with an angular spacing of 0.4° at 0.3 mAs/projection. Image quality was evaluated using (a) an 18-cm diameter electron density phantom (CIRS, Norfolk, VA) with nine contrast inserts and (b) the resolution section of the 20-cm diameter Catphan phantom (The Phantom Laboratory, Greenwich, NY). For the MAR studies, two opposing CIRS phantom inserts were replaced by steel rods. The reconstruction methods were based on combining MV and kV data into one sinogram. The MAR reconstruction utilized mostly kV raw data with only those rays corrupted by metal requiring replacement with MV data (total absorbed dose = 0.7 cGy). For the STR study, projections from partially overlapping 105°kV and MV acquisitions were combined to create a complete dataset that could have been acquired in 18 sec (absorbed dose = 2.5 cGy). MV-only (4.3 cGy) and kV-only (0.3 cGy) images were also reconstructed. RESULTS: The average signal-to-noise ratio (SNR) of the inserts in the MV-only CWO and GOS CIRS phantom images were 0.62× and 0.12× the SNR of the inserts in kV-only image, respectively. The limiting spatial resolutions in the MV-only GOS, MV-only CWO, and kV-only Catphan images were 3, 6, and 8 lp/cm, respectively. In the combined kV/CWO STR reconstruction, all contrast inserts were visible while only two were detectable in the kV/Cu-GOS image due to high levels of noise (average SNRs of kV/CWO and kV/GOS inserts were 0.97× and 0.18× the SNR of the kV-only inserts, respectively). In the kV-MV MAR reconstructions, streaking artifacts were substantially reduced with all inserts becoming clearly visible in the kV/CWO image while only two were visible in the kV/Cu-GOS image (average SNRs of the kV/CWO and kV/Cu-GOS CIRS with metal inserts were 0.94× and 0.35× the SNRs of the kV-only CIRS without metal inserts). CONCLUSIONS: We have demonstrated that a high-DQE MV detector can be applied to generating high-quality combined kV-MV images for SRT and MAR. Clinically acceptable doses were utilized.

Stress-dependent and gender-specific neuroregulatory roles of the apelin receptor in the hypothalamic-pituitary-adrenal axis response to acute stress.

The neuropeptide apelin is expressed in hypothalamic paraventricular and supraoptic nuclei and mediates its effects via activation of the apelin receptor (APJ). Evidence suggests a role for apelin and APJ in mediating the neuroendocrine response to stress. To understand the physiological role of APJ in regulation of the hypothalamic-pituitary-adrenal (HPA) axis, we measured ACTH and corticosterone (CORT) plasma levels in male and female mice lacking APJ (APJ knockout, APJ KO) and in wild-type controls, in response to a variety of acute stressors. Exposure to mild restraint, systemic injection of lipopolysaccharide (LPS), insulin-induced hypoglycaemia and forced swim (FS) stressors, elevated plasma ACTH and CORT levels in wild-type mice. Acute mild restraint significantly increased plasma ACTH and CORT to a similar level in APJ KO mice as in wild-type mice. However, an intact APJ was required for a conventional ACTH, but not CORT, response to LPS administration in male mice and to insulin-induced hypoglycaemia in male and female mice. In contrast, APJ KO mice displayed an impaired CORT response to acute FS stress, regardless of gender. These data indicate that APJ has a role in regulation of the HPA axis response to some acute stressors and has a gender-specific function in peripheral immune activation of the HPA axis.

The vasopressin V1b receptor modulates plasma corticosterone responses to dehydration-induced stress.

Vasopressin V1b receptor knockout (V1b⁻/⁻) mice were used to investigate a putative role for the V1b receptor (V1bR) in fluid regulation and in the hypothalamic-neurohypophysial system (HNS) and hypothalamic-pituitary-adrenal (HPA) axis responses to osmotic stress induced by water deprivation (WD). Male wild-type and V1b⁻/⁻ mice were housed in metabolic cages to allow determination of water intake and urine volume and osmolality. When provided with food and water ad lib., spontaneous urine volume and urine osmolality did not differ between genotypes. Similarly, WD for 24 h caused comparable decreases in urine volume and increases in urine osmolality irrespective of genotype. WD resulted in an increase in plasma corticosterone concentration in wild-type animals; however, this WD-induced increase in plasma corticosterone was significantly attenuated in V1b⁻/⁻ mice. Comparable increases in neuronal activation, indicated by increased c-fos mRNA expression, and in vasopressin mRNA expression occurred in both the supraoptic nucleus and paraventricular nucleus (PVN) of wild-type and V1b⁻/⁻ mice following WD; however, the WD-induced decrease in corticotrophin-releasing hormone mRNA expression seen in the PVN of wild-type mice was not observed in the PVN of V1b⁻/⁻ mice. These data suggest that, although the vasopressin V1bR is not required for normal HNS function, it is necessary for a full HPA-axis response to the osmotic stress of WD.

Stimulus-specific neuroendocrine responses to osmotic challenges in apelin receptor knockout mice.

The expression of the novel peptide apelin and its receptor APJ within specific regions of the brain, in particular the magnocellular neurones of the hypothalamus and the circumventricular organs, has implicated the apelinergic system in mechanisms controlling fluid homeostasis. In addition, apelin and APJ are considered to be involved in controlling arginine vasopressin (AVP) secretion into the circulation and release within the hypothalamic-neurohypophysial system. To clarify the role of APJ during regulation of fluid homeostasis, we compared the effects of osmotic stimulation on the urinary concentrating capacities and central nervous system responses of salt-loaded (SL) and water-deprived (WD) female APJ knockout (APJ(-/-)) mice and wild-type controls. SL resulted in a significantly increased urine volume in APJ(-/-) mice compared to wild-type controls, whereas WD in APJ(-/-) mice failed to reduce urine volume as seen in wild-type controls. AVP transcripts in the supraoptic and paraventricular nuclei and plasma AVP concentrations were significantly attenuated in SL APJ(-/-) mice compared to SL wild-type, but increased comparably in wild-type and APJ(-/-) mice after WD. Analysis of c-fos mRNA expression in the median preoptic nucleus and subfornical organ in response to either WD or SL showed attenuated expression in APJ(-/-) compared to wild-type mice. These findings further implicate the apelinergic system in mechanisms controlling fluid homeostasis, particularly at a neuroendocrine level, and suggest stimulus-specific involvement in vasopressinergic activity.

Environmental change in river channels: a neglected element. Towards geomorphological typologies, standards and monitoring.

Rivers integrate the impacts of change in atmospheric and terrestrial systems; they then deliver these to the coast. En route geomorphological processes create dynamic and diverse habitats, both in-stream and in riparian/floodplain ecotones. The dynamics of channel change conflict with human resource development, the outcome is that many river and riparian environments have been significantly modified, complicating the interpretation of change. Collection of geomorphological data on both form and process has to date been overwhelmingly an academic pursuit; standard measurement networks and long-term monitoring have, as a result been largely absent-as in the Environmental Change Network (ECN), despite the emerging requirements of legislation such as the EU Water Framework Directive. In this paper, we utilise a unique set of repeat channel surveys and long-term bed-load sediment yields to provide guidance on both definitions of change and those variables and survey techniques which might form the basis, in future, of improved national-scale monitoring. The Environment Agency's River Habitat Surveys suggest the basis for channel typologies that could structure a sampling framework and rationalise the variables to be monitored. We also point to the value of more detailed geomorphological procedures in use at the catchment/project scale-Catchment Baseline Surveys and Fluvial Audits-as a standardised basis for monitoring the detail of change in the fluvial sediment system. A perfect opportunity to lay foundations for such monitoring activity has been provided in England and Wales by the winter floods of 2000/2001.

Effect of different 5-HT1A receptor antagonists in combination with paroxetine on expression of the immediate-early gene Arc in rat brain.

Selective 5-HT(1A) receptor antagonists enhance the effect of selective serotonin reuptake inhibitors (SSRIs) on presynaptic 5-HT function, and have potential as antidepressant augmentation therapies. The present study tested the effect of different selective 5-HT(1A) receptor antagonists (WAY 100635, NAD-299, p-MPPI and LY 426965) in combination with a SSRI (paroxetine), on postsynaptic 5-HT function measured by increased expression of the immediate early gene, Arc. Paroxetine (5 mg/kg s.c.) combined with WAY 100635 (0.3 mg/kg s.c.) increased Arc mRNA in frontal, parietal and piriform cortices, and caudate putamen. Paroxetine (5 mg/kg s.c.) plus NAD-299 (1 or 5 mg/kg s.c.) had a similar effect. None of these drugs increased Arc mRNA when administered alone. Paroxetine (5 mg/kg s.c.) plus p-MPPI (8.5 mg/kg s.c.) also increased Arc mRNA but p-MPPI itself elevated Arc mRNA in many regions. Whilst LY 426965 (3 or 10 mg/kg s.c.) had no effect alone, when combined with paroxetine (5 mg/kg s.c.), the drug increased Arc mRNA in caudate putamen but not cortical regions.In conclusion, this study demonstrates that four 5-HT(1A) receptor antagonists augment the effect of an SSRI on Arc mRNA expression, which is suggestive of increased postsynaptic 5-HT function. However, the data reveal certain differences in the 5-HT(1A) receptor antagonists not recognised in models of presynaptic 5-HT function.