Spin Correlations in e+e−e^{+}e^{-} Pair Creation by Two-Photons and Entanglement in QED

Spin correlations of $e^{+}e^{-}$ pair productions of two colliding photons are investigated and explicit expressions for their corresponding probabilities are derived and found to be \textit{energy} (speed) dependent, for initially \textit{linearly} and \textit{circularly polarized} photons, different from those obtained by simply combining the spins of the relevant particles, for initially \textit{polarized} photons. These expressions also depend on the angles of spin of $e^{+}$ (and/or of $e^{-}$), for initially {\it linearly polarized} photons, but not for {\it circularly polarized} photons, as a function of the energy. It is remarkable that these explicit results obtained from quantum field theory show a clear violation of Bell's inequality of Local Hidden Variables theories at all {\it energies} beyond that of the threshold one for particle production, in support of quantum field theory in the relativistic regime. We hope that our explicit expression will lead to experiments, of the type described in the bulk of this paper, which can monitor energy (and speed) in polarization correlation experiments.Comment: 12 pages, 4 figure

Health Impairments in Children and Adolescents After Hospitalization for Acute COVID-19 or MIS-C

OBJECTIVES: To evaluate risk factors for postdischarge sequelae in children and adolescents hospitalized for acute coronavirus disease 2019 (COVID-19) or multisystem inflammatory syndrome in children (MIS-C). METHODS: Multicenter prospective cohort study conducted in 25 United States pediatric hospitals. Patients <21-years-old, hospitalized May 2020 to May 2021 for acute COVID-19 or MIS-C with follow-up 2 to 4 months after admission. We assessed readmissions, persistent symptoms or activity impairment, and new morbidities. Multivariable regression was used to calculate adjusted risk ratios (aRR) and 95% confidence intervals (CI). RESULTS: Of 358 eligible patients, 2 to 4 month survey data were available for 119 of 155 (76.8%) with acute COVID-19 and 160 of 203 (78.8%) with MIS-C. Thirteen (11%) patients with acute COVID-19 and 12 (8%) with MIS-C had a readmission. Thirty-two (26.9%) patients with acute COVID-19 had persistent symptoms (22.7%) or activity impairment (14.3%) and 48 (30.0%) with MIS-C had persistent symptoms (20.0%) or activity impairment (21.3%). For patients with acute COVID-19, persistent symptoms (aRR, 1.29 [95% CI, 1.04-1.59]) and activity impairment (aRR, 1.37 [95% CI, 1.06-1.78]) were associated with more organ systems involved. Patients with MIS-C and pre-existing respiratory conditions more frequently had persistent symptoms (aRR, 3.09 [95% CI, 1.55-6.14]) and those with obesity more frequently had activity impairment (aRR, 2.52 [95% CI, 1.35-4.69]). New morbidities were infrequent (9% COVID-19, 1% MIS-C). CONCLUSIONS: Over 1 in 4 children hospitalized with acute COVID-19 or MIS-C experienced persistent symptoms or activity impairment for at least 2 months. Patients with MIS-C and respiratory conditions or obesity are at higher risk of prolonged recovery

Meat production of mountain reedbuck

Thirty-nine adult mountain reedbuck (Redunco fulvorufula) were collected on the Loskop Dam Nature Reserve during 1971-72. Dressing percentages ranged from 44,0-62,4 % Seasonal variation in carcass masses and dressing percentages was pronounced with carcasses collected during July-October averaging 41 % lighter for males and 24% lighter for females than those collected during March-June. These differences may have been accentuated to some extent through age bias in the small sample taken, but tests on age indices based on tooth wear and horn ring counts indicate that age bias contributed little to the observed differences

Climatic influences on the behavioural ecology of Chanter's mountain reedbuck in Kenya

The effects of rainfall and temperature on the behavioural ecology of Chanler's mountain reedbuck (Redunca fulvorufula fulvorufula Rothschild) were examined on ranchland near Gilgil, Kenya. Ambient temperature was shown to be the proximate determinant of diurnal activity and rumination patterns. Mountain reedbuck were active during early morning and late afternoon, but rested and abandoned rumination when temperatures peaked at midday. There was close synchrony in levels of activity, rumination and use of cover and shade between males and females. Seasonal variations in time budgets were strongly influenced by rainfall patterns. Analyses revealed a one-month lag between rainfall and both peak grass growth and a decrease in rumination frequency. The proportion of time allocated to feeding decreased one month later, and was coincident with an increase in the proportion of grass in the diet. Reedbuck may therefore be prevented from exploiting high-quality new grass, possibly by gut-fill or induced imbalances in rumen pH. It is suggested that the unexpectedly high levels of browse in the diet is an adaptive response to low rainfall during the preceding two months