ABSTRACT
Water-rock interactions in aquifer systems are a key control on water quality but remain poorly understood. Lithium (Li) isotopes are useful for understanding water-rock interactions, but there are few data available for groundwater aquifers. Here we present a Li isotope dataset for rainfall and groundwater samples from a carbonate island aquifer system: Rottnest Island, Western Australia. This dataset was complemented by strontium (Sr) isotope and major and trace element data for groundwaters, and leaching experiments on bedrock samples. The δ7Li values and 87Sr/86Sr ratios of fresh groundwaters ranged from +23 to +36 and 0.709167 to 0.709198, respectively. Mass balance calculations indicated that silicate weathering supplied ~60 and 70% of dissolved Li and Sr in fresh groundwaters, respectively, with the remainder provided by atmospheric input, and carbonate weathering; for major cations, the majority of calcium and sodium (Na) are supplied by carbonate weathering and atmospheric input, respectively. The estimated low proportion of Sr produced by carbonate weathering was surprising in a carbonate aquifer, and the 87Sr/86Sr data indicated that the silicate Sr source had low Rb/Sr and 87Sr/86Sr ratios. There was an increase in the maximum δ7Li values in fresh groundwaters (+36) relative to the maximum value in rainfall and seawater (ca. +31). As clay minerals are undersaturated in fresh groundwaters, this increase may be explained by Li isotope fractionation associated with ion-exchange reactions on clays and iron(oxy)hydroxides. In the more saline groundwaters, the minimum δ7Li values decreased with depth to +14.5, suggesting increased silicate mineral dissolution in the deeper aquifer. These results reveal the importance of water-rock interactions in a coastal carbonate aquifer, and demonstrate the usefulness of Li isotopes for tracing weathering reactions in an environmental setting where traditional weathering tracers, such as sodium and Sr isotopes, are less appropriate.
ABSTRACT
BACKGROUND: Child survival initiatives historically prioritized efforts to reduce child morbidity and mortality from infectious diseases and maternal conditions. Little attention has been devoted to paediatric injuries in resource-limited settings. This study aimed to evaluate the demographics and outcomes of paediatric injury in a sub-Saharan African country in an effort to improve prevention and treatment. METHODS: A prospective trauma registry was established at the two university teaching campuses of the University of Rwanda to record systematically patient demographics, prehospital care, initial physiology and patient outcomes from May 2011 to July 2015. Univariable analysis was performed for demographic characteristics, injury mechanisms, geographical location and outcomes. Multivariable analysis was performed for mortality estimates. RESULTS: Of 11 036 patients in the registry, 3010 (27·3 per cent) were under 18 years of age. Paediatric patients were predominantly boys (69·9 per cent) and the median age was 8 years. The mortality rate was 4·8 per cent. Falls were the most common injury (45·3 per cent), followed by road traffic accidents (30·9 per cent), burns (10·7 per cent) and blunt force/assault (7·5 per cent). Patients treated in the capital city, Kigali, had a higher incidence of head injury (7·6 per cent versus 2·0 per cent in a rural town, P < 0·001; odds ratio (OR) 4·08, 95 per cent c.i. 2·61 to 6·38) and a higher overall injury-related mortality rate (adjusted OR 3·00, 1·50 to 6·01; P = 0·019). Pedestrians had higher overall injury-related mortality compared with other road users (adjusted OR 3·26, 1·37 to 7·73; P = 0·007). CONCLUSION: Paediatric injury is a significant contributor to morbidity and mortality. Delineating trauma demographics is important when planning resource utilization and capacity-building efforts to address paediatric injury in low-resource settings and identify vulnerable populations.
ANTECEDENTES: Históricamente, las iniciativas relativas a la supervivencia pediátrica han priorizado los esfuerzos para reducir la morbilidad y la mortalidad debida a enfermedades infecciosas y patología materna. Se ha prestado escasa atención a los traumatismos en pediatría en entornos de recursos limitados. El objetivo de este estudio ha sido evaluar la demografía y los resultados de los traumatismos pediátricos en un país del África subsahariana en un intento para mejorar la prevención y el tratamiento. MÉTODOS: Se estableció un registro prospectivo de traumatismos en dos campus universitarios de Ruanda para recoger sistemáticamente las características demográficas, atención pre-hospitalaria, fisiología inicial y resultados, de mayo de 2011 a julio de 2015. Se efectuó un análisis univariado para los datos demográficos, mecanismos del traumatismo, localización geográfica y resultados. Para las estimaciones de mortalidad se llevó a cabo un análisis multivariable. RESULTADOS: De un total de 11.036 pacientes incluidos en el registro, 3.010 (27,3%) tenían menos de 18 años. Los pacientes pediátricos eran predominantemente varones (69,9%) con una edad media de 8,3 años. Las caídas fueron la causa más frecuente del traumatismo (45,3%) seguidas de los accidentes de tráfico (30,9%), quemaduras (10,7%) y traumatismo cerrado/asalto (7,5%). Los pacientes tratados en la capital presentaban una incidencia más elevada de traumatismos craneales (7,5% versus 2,0%, P < 0,0001, razón de oportunidades, odds ratio, OR 4,08, i.c. del 95% 2,6-6,4) y una mayor mortalidad global relacionada con el traumatismo (P = 0,019, OR ajustado 3,00, i.c. del 95% 1,5-6,0). Los peatones presentaron una mortalidad global relacionada con el traumatismo más alta en comparación con otros usuarios de la carretera (P = 0,0074, OR ajustado 3,26, i.c. del 95% 1,37-7,73). CONCLUSIÓN: Los traumatismos pediátricos contribuyen significativamente a la morbilidad y mortalidad. Delinear la demografía de los traumatismos es importante a la hora de planificar el uso de recursos y el desarrollo de capacidades dirigidas al esfuerzo para abordar los traumatismos pediátricos en entornos de bajos recursos e identificar poblaciones vulnerables.
Subject(s)
Emergency Medical Services/statistics & numerical data , Wounds and Injuries/diagnosis , Wounds and Injuries/epidemiology , Adolescent , Child , Child, Preschool , Emergency Medical Services/methods , Female , Humans , Incidence , Infant , Infant, Newborn , Logistic Models , Male , Multivariate Analysis , Prospective Studies , Registries/statistics & numerical data , Rwanda/epidemiology , Wounds and Injuries/mortalityABSTRACT
RATIONALE: The structurally related neuropeptides, substance P, neurokinin A, and neurokinin B, belong to a family of molecules termed tachykinins and are widely distributed in the central and peripheral nervous systems. These peptides mediate their effects through three G protein coupled receptor subtypes, the neurokinin-1, neurokinin-2 and neurokinin-3 receptors, respectively. OBJECTIVE: To study the physiological functions of NK3, a line of NK3 knockout mice were generated and characterized in a broad spectrum of well-established behavioral tests. RESULTS: In several tests, including spontaneous locomotor activity, elevated plus maze, forced swim, and hot plate, wild-type and knockout mice performed similarly. However, in several cognition tests, including passive avoidance, acquisition of conditioned avoidance responding (CAR), and the Morris water maze, NK3 knockout mice displayed deficits compared to wild-type mice. Although NK3 wild-type and knockout mice performed similarly in the training phase of the passive avoidance test, knockout mice had shorter latencies to enter the dark compartment on days 3 and 4, suggesting impaired retention. In the acquisition phase of the conditioned avoidance responding assay, NK3 knockout mice acquired the CAR task at a slower rate than wild-type mice. Once the CAR test was acquired, both NK3 wild-type and knockout mice responded similarly to clozapine and risperidone, drugs which suppress responding in this test. In the Morris water maze, NK3 knockout mice showed increased latencies to find the escape platform on day 3 of training, suggesting a modest, but significant delay in acquisition compared to wild-type mice. CONCLUSION: These studies suggest a role for NK3 in learning and memory in mice.
