Projective Geometry and PT\cal PT-Symmetric Dirac Hamiltonian

The $(3 + 1)$-dimensional (generalized) Dirac equation is shown to have the same form as the equation expressing the condition that a given point lies on a given line in 3-dimensional projective space. The resulting Hamiltonian with a $\gamma_5$ mass term is not Hermitian, but is invariant under the combined transformation of parity reflection $\cal P$ and time reversal $\cal T$. When the $\cal PT$ symmetry is unbroken, the energy spectrum of the free spin-$\frac {1}{2}$ theory is real, with an appropriately shifted mass.Comment: 7 pages, LaTeX; version accepted for publication in Phys. Lett. B; revised version incorporates useful suggestions from an anonymous refere

The association of cannabis use with quality of life and psychosocial functioning in psychosis

BACKGROUND: Cannabis use is highly prevalent among people with a psychotic disorder. They often report sociality, coping with unpleasant affect and having positive experiences as important reasons for cannabis use, suggesting that cannabis improves their quality of life (QoL) and psychosocial functioning. However, based on previous studies we hypothesize that cannabis use is negatively associated with long-term subjective QoL and psychosocial functioning in people with a psychotic disorder. METHODS: We included 2994 people with a psychotic disorder (36.4% female), mean age 44.4 (SD 11.9), mean illness duration 17.2 years (SD 11.1), who participated in two yearly routine outcome assessments between 2014 and 2018 (interval 9-15 months) from the naturalistic PHAMOUS cohort study. Linear regression analyses were used to examine whether first assessment cannabis use was associated with QoL (ManSA) and psychosocial functioning (HoNOS). Changes in outcomes between assessments were analyzed with AN(C)OVA, to examine differences between continuers (n = 255), discontinuers (n = 85), starters (n = 83) and non-users (n = 2571). RESULTS: At first assessment, 11.4% was using cannabis. They had lower QoL (B = -2.93, p < 0.001) and worse psychosocial functioning (B = 1.03, p = 0.002) than non-users. After one year, changes in QoL and psychosocial functioning were not significantly different between continuers, starters, discontinuers and non-users. CONCLUSIONS: Cannabis users were less satisfied with their family relations and financial situation and showed more aggressive and disruptive behavior and self-harm than non-users. These differences are likely the result of patients having used cannabis for many years. Starting or discontinuing cannabis did not lead to changes in QoL and psychosocial functioning within one year

The Anesthetic Effects on Vasopressor Modulation of Cerebral Blood Flow in an Immature Swine Model

BACKGROUND: The effect of various sedatives and anesthetics on vasopressor modulation of cerebral blood flow (CBF) in children is unclear. In adults, isoflurane has been described to decrease CBF to a lesser extent than fentanyl and midazolam. Most large-animal models of neurocritical care use inhaled anesthetics for anesthesia. Investigations involving modulations of CBF would have improved translatability within a model that more closely approximates the current practice in the pediatric intensive care unit. METHODS: Fifteen 4-week-old piglets were given 1 of 2 anesthetic protocols: total IV anesthesia (TIVA) (midazolam 1 mg/kg/h and fentanyl 100 μg/kg/h, n = 8) or ISO (isoflurane 1.5%–2% and fentanyl 100 μg/kg/h, n = 7). Mean arterial blood pressure, intracranial pressure (ICP), CBF, and brain tissue oxygen tension were measured continuously as piglets were exposed to escalating doses of arginine vasopressin, norepinephrine (NE), and phenylephrine (PE). RESULTS: Baseline CBF was similar in the 2 groups (ISO 38 ± 10 vs TIVA 35 ± 26 mL/100 g/min) despite lower baseline cerebral perfusion pressure in the ISO group (45 ± 11 vs 71 ± 11 mm Hg; P \u3c 0.0005). Piglets in the ISO group displayed increases in ICP with PE and NE (11 ± 4 vs 16 ± 4 mm Hg and 11 ± 8 vs 18 ± 5 mm Hg; P \u3c 0.05), but in the TIVA group, only exposure to PE resulted in increases in ICP when comparing maximal dose values with baseline data (11 ± 4 vs 15 ± 5 mm Hg; P \u3c 0.05). Normalized CBF displayed statistically significant increases regarding anesthetic group and vasopressor dose when piglets were exposed to NE and PE (P \u3c 0.05), suggesting an impairment of autoregulation within ISO, but not TIVA. CONCLUSION: The vasopressor effect on CBF was limited when using a narcotic-benzodiazepine–based anesthetic protocol compared with volatile anesthetics, consistent with a preservation of autoregulation. Selection of anesthetic drugs is critical to investigate mechanisms of cerebrovascular hemodynamics, and in translating critical care investigations between the laboratory and bedside

Dispersion-theoretical analysis of the nucleon electromagnetic form factors: Inclusion of time-like data

We update a recent dispersion--theoretical fit to the nucleon electromagnetic form factors by including the existing data in the time--like region. We show that while the time--like data for the proton can be described consistently with the existing world space--like data, this is not the case for the neutron. Another measurement of the process $e^+ e^- \to \bar n n$ is called for. We furthermore sharpen the previous estimate of the separation between the perturbative and the non--perturbative regime, which is characterized by a scale parameter $\Lambda^2 \simeq 10\,$GeV$^2$.Comment: 7 pp, LaTeX, uses epsf, 2 figures in separate file, four data points changed, slight changes in the fits, conclusions unchange

Extraction of electromagnetic neutron form factors through inclusive and exclusive polarized electron scattering on polarized 3He target

Inclusive 3He(e,e') and exclusive 3He(e,e'n) processes with polarized electrons and 3He have been theoretically analyzed and values for the magnetic and electric neutron form factors have been extracted. In both cases the form factor values agree well with the ones extracted from processes on the deuteron. Our results are based on Faddeev solutions, modern NN forces and partially on the incorporation of mesonic exchange currents.Comment: 28 pages, 29 Postscript figure

Progress in drug metabolism, volume 1 Edited by J. W. Bridges and L. F. Chasseaud John Wiley and Sons; London, New York, Sydney, Toronto, 1976 xiii + 286 pages. $ 19.75, £ 9.80

Objective: People with psychotic disorders have an increased metabolic risk and a shortened life expectancy compared to the general population. Two large studies showed that metabolic disorders were untreated in a majority of the patients. Since then, guidelines have urged monitoring of metabolic health. This study examined the course of metabolic disorders over time in people with psychotic disorders and investigated current treatment rates. Methods: A total of 1,259 patients with psychotic disorders, as defined by the DSM-IV, from 4 Dutch mental health institutions participated in 3 yearly assessments of the Pharmacotherapy Monitoring and Outcome Survey (PHAMOUS) between 2006 and 2014. Patients' metabolic parameters were measured, and the use of pharmacologic treatment for hypertension (systolic blood pressure >= 140 mm Hg and/or diastolic blood pressure >= 90 mm Hg), dyslipidemia (5% = 2.5 mmol/L or SCORE risk >= 10% and LDL cholesterol level >= 1.8 mmol/L and/or triglycerides >= 2.3 mmol/L), and hyperglycemia (hemoglobin A(1c) concentration > 7% and/or fasting glucose concentration >= 7.2 mmol/L) was recorded. Results: Prevalence of the metabolic syndrome, as defined by the National Cholesterol Education Program criteria, was > 50% at each assessment. On the basis of the European Society of Cardiology guidelines, pharmacotherapy for metabolic disorders was recommended for 52%-59% of the patients at each assessment. Treatment rates with antihypertensive (from 31% to 38%, P <.001) pharmacotherapy increased throughout the assessments. However, half of the patients were not treated for their metabolic risk factors while being monitored for 3 years or longer. Older patients were more likely to receive treatment, and patients who received treatment had lower blood pressure and lower cholesterol and triglyceride concentrations than patients not receiving the recommended treatment. Conclusions: Metabolic risk factors are still seriously undertreated in people with psychotic disorders. Better adherence to and better implementation of guidelines about monitoring and treating metabolic disorders in psychiatry are crucial. (C) Copyright 2017 Physicians Postgraduate Press, Inc

Effect of recent R_p and R_n measurements on extended Gari-Krumpelmann model fits to nucleon electromagnetic form factors

The Gari-Krumpelmann (GK) models of nucleon electromagnetic form factors, in which the rho, omega, and phi vector meson pole contributions evolve at high momentum transfer to conform to the predictions of perturbative QCD (pQCD), was recently extended to include the width of the rho meson by substituting the result of dispersion relations for the pole and the addition of rho' (1450) isovector vector meson pole. This extended model was shown to produce a good overall fit to all the available nucleon electromagnetic form factor (emff) data. Since then new polarization data shows that the electric to magnetic ratios R_p and R_n obtained are not consistent with the older G_{Ep} and G_{En} data in their range of momentum transfer. The model is further extended to include the omega' (1419) isoscalar vector meson pole. It is found that while this GKex cannot simultaneously fit the new R_p and the old G_{En} data, it can fit the new R_p and R_n well simultaneously. An excellent fit to all the remaining data is obtained when the inconsistent G_{Ep} and G_{En} is omitted. The model predictions are shown up to momentum transfer squared, Q^2, of 8 GeV^2/c^2.Comment: 14 pages, 8 figures, using RevTeX4; email correspondence to [email protected] ; minor typos corrected, figures added, conclusions extende