We analyze the effect of atmospheric Kolmogorov turbulence on entangled orbital angular momentum states generated by parametric down-conversion. We calculate joint and signal photon detection probabilities and obtain numerically their dependence on the mode-width-to-Fried-parameter ratio. We demonstrate that entangled photons are less robust to the effects of Kolmogorov turbulence compared to single photons. In contrast, signal photons are more robust than single photons in the lowest-order mode.We also obtain numerically a scaling relation between the value of the mode-width-to-Fried-parameter ratio for which the joint detection probabilities is a maximum and the momentum mismatch between signal and idler photons after propagation through the medium. PACS codes: 42.50.Dv; 42.68.Bz IntroductionQuantum communication utilizing the phenomenon of entanglement has many applications such as quantum teleportation [1], quantum cryptography [2, 3] and superdense coding [4]. Multidimensional entangled orbital angular momentum (OAM) states can be utilized to generate arbitrary base-N quantum digits thereby allowing the implementation of higher capacity optical communication systems. This feature has generated considerable interest with respect to encoding quantum and classical information [2,5]. In addition it has been shown that the (OAM) of photons can be used to encode data onto a laser beam for transmitting information in free-space optical systems [6]. The performance of free-space optical communication systems is however severely degraded by decoherence caused by atmospheric turbulence in the optical channel, resulting in fluctuations in both the intensity and phase of the received signal. Recently, C. Paterson [7] estimated the theoretical performance limits for communication links based on the OAM of single photons with no entanglement. It was demonstrated that for Kolmogorov atmospheric statistics this system is significantly affected, even in the weak turbulence regime, with narrower and lower-order modes being more robust. Spontaneous parametric downconversion generates pairs of down-converted photons entangled in OAM [5]. It has been demonstrated that Laguerre-Gaussian (LG) modes possess well defined orbital angular momemta [8]. In the paraxial approximation, these modes are the eigenstates of the orbital angular momentum operator with eigenvalue equal to h l per photon. Xi-Fen Ren et al [9] calculated the superposition coefficients of down converted correlated LG modes and showed that this probability amplitude decreases almost exponentially with increasing OAM. In this paper we investigate the effects of Kolmogorov turbulence on entangled OAM photon states by calculating the joint detection probability of entangled LG modes. We compare the effects of Kolmogorov turbulence on entangled photon pairs and single photons.

Few studies have been conducted on the incidence and factors which contribute to road traffic collisions in Trinidad. In order to fill this gap in knowledge, we conducted knowledge, attitudes and practice (KAP) study among drivers to determine which factors contributed to these accidents. A questionnaire was developed and administered using a cross-sectional approach among 3000 persons living in 5 different areas of Trinidad. The collected data were analysed using SPSS version 22, t-test and multivariate analysis. Of the 2998 respondents, at least 572 (19.1%) had been involved in one or more road collisions. While only 46.7% of respondents always wore seat belts, approximately 93% believed strongly that their use was essential for safety-a 3-fold increase in that found in a previous study. The multiple regression analysis indicated that attitude and age were significantly associated with accidents and increased risk for accidents. The results showed that alcohol consumption, use of mobile phones while driving, speed, and age were significantly (p > 0.001) associated with accidents. In conclusion, most respondents were aware of traffic laws and regulations, but their knowledge and practice often diverged. However the improvement in attitude to seat-belt wearing suggests that a holistic driver education program may improve driver practice and adherence to the road traffic regulations in Trinidad.

Summary of what was known• Few studies on road traffic collisions conducted in Latin American and the Caribbean region• Increasing car ownership within the region• Lack of seatbelt usage in Trinidad• Most accidents are associated with alcohol usage• High mortality among pedestriansSummary of what this study adds• Most collisions occur at night• Most collisions occur at weekends• Collisions are evenly distributed throughout the year• More males than females die in fatal collisions• The most productive age group (15–44) is affected the most• More drivers than pedestrians are affected• Reflects the pattern of developed rather than developing countries with respect to time of day for RTCsBackgroundThe purpose of the study is to determine the epidemiology of road traffic collisions (RTCs) in Trinidad and Tobago by characterizing RTCs in terms of number of collisions, fatalities, victim profiles, and locations for the purpose of informing accident prevention programs. Previous studies of RTCs in Trinidad and Tobago were primarily concerned with patterns of drivers use of seat belts, road collisions as a cause of mortality in young men, and the economic burden of road collisions. Attempts were made to model road fatalities, but limited epidemiological data meant that it was difficult to determine trends or develop models.MethodsThis study determined the epidemiology of RTCs in Trinidad and Tobago over the period 2000–2011 using data collected by the Trinidad and Tobago Road Traffic Branch of the Police Service and secondary data from the Central Statistical Office. Data were analyzed using Excel, SPSS, and R statistical packages.ResultsFatalities were greater among men (80%) than among women (20%) and were highest on two major freeways in Trinidad [the Churchill–Roosevelt Highway and the Sir Solomon Hochoy Highway]. Most collisions occurred during the night among individuals between the ages of 15 and 44 years. Fatalities among drivers steadily increased over the study period and overtook fatalities among pedestrians, who were the group most affected in 2000. Most fatalities occurred at weekends.ConclusionsThese patterns can inform (i) education programs and (ii) road and traffic control measures.

Introduction. Understanding the symptoms associated with COVID-19 cases that require intensive care unit (ICU) attention is important in management of the life threatening case of the disease. Method : This study was carried out with the aim of determining the laboratory indicators of ICU admission. Data from 126 COVID-19 patients (ICU patients, n = 18, Non-ICU, n = 98) were analyzed from a Caribbean Territory.Results: The median age for the non-ICU patients was 59.0 (IQR = 23.5) years while the ICU patients had a median age of 62.5 (IQR = 17.5). The univariate analysis indicted that laboratory indicators that were significantly associated with ICU admission included WBC (P = 0.037), lymphocyte (P = 0.016), LDH (P = 0.002), AST (P = 0.005) and CRP (P = 0.0001). However, multivariate analysis that included WBC, neutrophil, lymphocyte, PLT, AST, LDH, ALT, and CRP indicated that only AST was associated with high odds of patients being admitted to ICU (OR .002, 95% CI 0.000-.004, P = 0.017). Statistically significant area under the curve (AUC) were obtained for Neutrophil (AUC = 0.704, P = 0.007), CRP (AUC = 0.81, p= 0.00) and LDH (AUC=0.766, P= 0.00) and AST (AUC= 0.729, P= 0.003). Conclusion: The findings indicate that neutrophils, AST and LDH’s ROC curves are good tests while CRP curve is a very good test. However, lymphocyte curve is a poor test for determining COVID-19 patient for ICU admission. Neutrophil, AST, LDH and CRP are suitable predictors of COVID-19 patients that should receive ICU care

Background. COVID-19 vaccine acceptance is important in ensuring the widespread vaccination of the population to achieve herd immunity. Establishing the acceptance of vaccines among healthcare workers, who play a vital role in an immunization program’s success, is important. The aim of this study was to assess the influence of social trust and demographic factors on COVID-19 vaccine acceptance among healthcare workers. Methods. A cross-sectional survey utilizing an electronic questionnaire inquiring about COVID-19 vaccine uptake, preferences, and concerns was distributed via e-mail to 1,351 North Central Regional Health Authority (NCRHA) healthcare workers of the following categories: medical practitioners, nursing personnel, veterinary surgeons, medical interns, dental interns, paramedics, and pharmacists. These professions were selected as they were granted power to administer COVID-19 vaccines during the period of public emergency by the President of Trinidad and Tobago and were therefore likely to be NCRHA healthcare workers directly involved in vaccine administration services. Bivariate analysis using Chi-squared analysis of association was used to determine the association between the respondents’ characteristics and the acceptance of the vaccine and the association between vaccine acceptance among healthcare workers and trust. The association between the acceptance of the COVID-19 vaccines and healthcare workers’ characteristics and trust was established using multinomial logistic regression. Results. A total of 584 healthcare workers took part in the study, and 1.4% showed unwillingness to receive the COVID-19 vaccine. The study indicates that age, profession, trust in international public health organizations, and trust in other healthcare providers predict the uptake of COVID-19 vaccines among healthcare workers, with younger age groups and the nursing profession associated with an unwillingness to accept the vaccine. Gender of the healthcare workers does not predict vaccine acceptance. Conclusions and relevance: efforts towards enhanced vaccine acceptance among healthcare workers should take into consideration age, profession, and the trust in international organizations and other healthcare providers. Sensitization programs aimed at informing and creating awareness among healthcare workers about the COVID-19 vaccines should be age-specific as well as occupation-based.