On hadron deformation: a model independent extraction of EMR from pion photoproduction data

The multipole content of pion photoproduction at the $\Delta^+ (1232)$ resonance has been extracted from a data set dominated by recent Mainz Microtron (MAMI) precision measurements. The analysis has been carried out in the Athens Model Independent Analysis Scheme (AMIAS), thus eliminating any model bias. The benchmark quantity for nucleon deformation, $EMR = E2/M1 = E_{1+}^{3/2}/M_{1+}^{3/2}$, was determined to be $-2.5 \pm 0.4_{stat+syst}$, thus reconfirming in a model independent way that the conjecture of baryon deformation is valid. The derived multipole amplitudes provide stringent constraints on QCD simulations and QCD inspired models striving to describe hadronic structure. They are in good agreement with phenomenological models which explicitly incorporate pionic degrees of freedom and with lattice QCD calculations.Comment: 14 pages, 9 figures, 2 table

Individual and area-level risk factors for suicidal ideation and attempt in people with severe depression

INTRODUCTION: Previous research has identified several risk factors that are strongly associated with suicidal behavior in patients with severe depression. However, the effects of area-level characteristics on suicidal ideation and attempt in this population remain unclear. METHODS: The Clinical Record Interactive Search (CRIS) database was used to identify 2587 patients with severe depression who received secondary mental health services from the Camden & Islington NHS Foundation Trust. Stepwise multivariable logistic regression models were used to examine associations between socio-demographic characteristics, clinical variables, area-level measures, and suicidal ideation and attempt as separate outcomes. RESULTS: Both suicidal ideation and attempts were common among this cohort of severely depressed individuals (70.5% and 37.7%, respectively). While several individual socio-demographic and clinical characteristics were associated with both outcomes, particularly past psychiatric admission (suicidal ideation: adjusted OR=2.86, 95% CI: 2.26-3.62; suicide attempt: adjusted OR=4.00, 95% CI: 3.30-4.89), neither social deprivation nor ethnic density (measured at the area-level) was associated with risk for either outcome. LIMITATIONS: Data were not collected specifically for research purposes and hence information on some potential confounders was not available. Additionally, information was restricted to individuals who accessed secondary mental health services in a defined catchment area and period. The study therefore does not take into account individuals who did not access mental health services. CONCLUSIONS: The variation in risk for suicidal ideation and attempt among severely depressed individuals is explained by differences in individual socio-demographic and clinical characteristics, most notably past psychiatric admission and substance misuse, and not by area-level measures

Patterns of responding differentiate intravenous nicotine self-administration from responding for a visual stimulus in C57BL/6J mice

Testing genetically engineered mice in a reliable nicotine self-administration procedure could provide important insights into the molecular mechanisms underlying nicotine reinforcement. We assessed operant responding for intravenous nicotine infusions in C57BL/6J male mice under a fixed-ratio 3 schedule of reinforcement in which a visual cue was contingently associated with drug delivery. Acquisition, dose-response function, extinction, and cue-induced reinstatement of operant behavior were characterized. Low nicotine doses (0.001-0.06 mg/kg/infusion) elicited response rates similar to those supported by saline, whereas a higher dose (0.1 mg/kg/infusion) decreased responding. Using an identical procedure to assess cocaine self-administration in an independent group of mice yielded an inverted U-shaped dose-response curve. Other mice trained to respond exclusively for the visual stimulus earned a similar number of reinforcers as mice self-administering saline or low nicotine doses, although with a lower selectivity for the active lever and their response rates were sensitive to the discontinuation and resumption of cue light presentation. Finally, patterns of responding for nicotine, cocaine, or the visual stimulus alone were analyzed using frequency distributions of inter-response intervals and extended return maps. These analyses revealed unique properties of nicotine, which dose-dependently delayed the first response post-timeout and increased the regularity of lever pressing activity. Nicotine did not enhance the reinforcing properties of the visual cue paired with drug delivery. Interestingly, however, patterns of responding could differentiate nicotine self-administration from responding for a visual stimulus or saline and indicated that nicotine functioned as a salient stimulus driving highly regular operant behavior

The Effects of Cariprazine and Aripiprazole on PCP-Induced Deficits on Attention Assessed in the 5-Choice Serial Reaction Time Task

Attentional processing deficits are a core feature of schizophrenia, likely contributing to the persistent functional and occupational disability observed in patients with schizophrenia. The pathophysiology of schizophrenia is hypothesized to involve dysregulation of NMDA receptor-mediated glutamate transmission, contributing to disruptions in normal dopamine transmission. Preclinical investigations often use NMDA receptor antagonists, such as phencyclidine (PCP), to induce cognitive disruptions relevant to schizophrenia. We sought to test the ability of partial dopamine D-2/D-3 agonists, cariprazine and aripiprazole, to attenuate PCP-induced deficits in attentional performance. The objective of this study is to determine whether systemic administration of cariprazine or aripiprazole attenuated 5-choice serial reaction time task (5-CSRTT) deficits induced by repeated exposure to PCP. We utilized a repeated PCP-treatment regimen (2 mg/kg, subcutaneous [s.c.], once daily for 5 days) in rats to induce deficits in the 5-CSRTT. Rats were pre-treated with cariprazine (0.03, 0.1, or 0.3 mg/kg, oral [p.o.]) or aripiprazole (1, 3, or 10 mg/kg, p.o.) to determine whether they prevented PCP-induced deficits in the 5-CSRTT performance. PCP treatment increased inappropriate responding in the 5-CSRTT, elevating incorrect, premature, and timeout responses. Cariprazine treatment reduced PCP-induced increases in inappropriate responding. However, at higher doses, cariprazine produced non-specific response suppression, confounding interpretation of the attenuated PCP-induced deficits. Aripiprazole treatment also attenuated PCP-induced deficits; however, unlike cariprazine treatment, aripiprazole reduced correct responding and increased omissions. Cariprazine and aripiprazole both demonstrated potential in attenuating PCP-induced deficits in the 5-CSRTT performance. While both compounds produced non-specific response suppression, these effects were absent when 0.03 mg/kg cariprazine was administered