Gas exchange and chlorophyll a fluorescence measurements as proxies of X-ray resistance in Phaseolus vulgaris L.

Phaseolus vulgaris L. plants were irradiated with different doses (0.3, 10, 50 and 100 Gy) of X-rays in order to obtain a reference curve of response to ionizing radiations for this species. Growth analysis, gas exchange and chlorophyll a fluorescence measurements were performed to estimate the radio-resistance of bean plants. Specifically, there was a negative influence of X-rays on the net photosynthesis rate at 50 and 100 Gy, already on the day of irradiation. Experimental data showed a recovery over time in the gas exchange while the theoretical maximum photochemical efficiency of the photosystem II (Fv/Fm) was fairly constant throughout the period of measurements (20 days) and for all the experimental conditions. On the other hand, the quantum yield of PSII linear electron transport (ΦPSII) and non-photochemical quenching (NPQ) were deeply influenced over time by X-ray dose, suggesting a decrease in the functionality of the photosynthetic apparatus at the highest radiation doses. The growth was affected only at the highest doses of radiation with a significant and severe reduction of leaf expansion and number of leaves per plant. Despite the arrest in growth, X-ray exposure seems to trigger an increased photochemical activity probably signifying that P. vulgaris plants have a fairly elevated resistance to this kind of ionizing radiation. Our current results will provide a complete analysis of the photosystem II (PSII) response of P. vulgaris to different doses (0.3, 10, 50 and 100 Gy) of X-rays, providing sound references for both space-oriented and radioecology questions.

Child Abuse and Neglect and its Psycho-Physical and Social Consequences: A Review of the Literature.

Child maltreatment is a complex life experience occurs when a parent or caregiver does an intentional or potential damage to a child, including acts of commission and omission. Child abuse is not an uncommon event, but it is not always recognized. Identifying the real number of maltreated children is a challenge because of the large variability in reported prevalence data across studies. Unfortunately, in the United States, it affects 1 in 8 children, by the age of 18 years, annually. Paediatricians may encounter a variety of forms of maltreatment such as neglect, emotional, physical and sexual abuse. These aspects should be recognised, examined and evaluated by employing a systematic approach and focusing on basic needs of children that may not be met. Child maltreatment is a global problem with serious life-long physical and psychological or psychiatric outcomes. It is associated with important economic and social costs (such as physical and mental health, productivity losses, child welfare, criminal justice and special education costs) due to its high prevalence and its long-term and short-term consequences. In the United States, the average cost of nonfatal maltreatment is $210,012 per children and the cost of fatal maltreatment is $1,272,900. General Practitioners are quite prepared to face the problem of child maltreatment: since they have the opportunity to meet several members of the same family, they can detect stressors that put children at risk of maltreatment. All health professionals have the responsibility to protect children from abuse and neglect.

A revised energy partitioning approach to assess the yields of non-photochemical quenching components.

Non-photochemical quenching (NPQ) is a complex and still unclear mechanism essential for higher plants. The intensive research on this subject has highlighted three main components of NPQ: energy-dependent process (qE); state transitions to balance the excitation of PSII and PSI (qT); and photoinhibitory processes (qI). Recently, these components have been resolved as quantum yields according to the energy partitioning approach that takes into account the rate constants of every process involved in the quenching mechanisms of excited chlorophylls. In this study a fully extended quantum yield approach and the introduction of novel equations to assess the yields of each NPQ component are presented. Furthermore, a complete analysis of the yield of NPQ in Beta vulgaris exposed to different irradiances has been carried out. In agreement with experimental results here it is shown that the previous approach may amplify the yield of qE component and flatten the quantitative results of fluorescence analysis. Moreover, the significance of taking into account the physiological variability of NPQ for a correct assessment of energy partitioning is demonstrated.