A Developmental Perspective on Community Service in Adolescence

A substantial number of U.S. adolescents currently participate in community service and there is increased national interest in service programs. This article assesses the assumption of developmental benefits to service participants by critically reviewing 44 empirical studies. It offers a theoretical framework for understanding the findings by connecting them to identity development and delineating three pertinent concepts: agency, social relatedness, and moral-political awareness. These concepts are applied to studies that investigate: ( 1) the characteristics and motivations of participants, ( 2) the effects of service, and ( 3) the process of service. The findings support the conclusion that service activities which provide opportunities for intense experiences and social interactions are often associated with prosocial development. The findings also point to the need for more studies focused on particular service programs and on relationships between service providers and those served

Folic Acid Exposure Rescues Spina Bifida Aperta Phenotypes in Human Induced Pluripotent Stem Cell Model

Neural tube defects (NTDs) are severe congenital abnormalities, caused by failed closure of neural tube during early embryonic development. Periconceptional folic acid (FA) supplementation greatly reduces the risk of NTDs. However, the molecular mechanisms behind NTDs and the preventive role of FA remain unclear. Here, we use human induced pluripotent stem cells (iPSCs) derived from fetuses with spina bifida aperta (SBA) to study the pathophysiology of NTDs and explore the effects of FA exposure. We report that FA exposure in SBA model is necessary for the proper formation and maturation of neural tube structures and robust differentiation of mesodermal derivatives. Additionally, we show that the folate antagonist methotrexate dramatically affects the formation of neural tube structures and FA partially reverts this aberrant phenotype. In conclusion, we present a novel model for human NTDs and provide evidence that it is a powerful tool to investigate the molecular mechanisms underlying NTDs, test drugs for therapeutic approaches

Targeting ASIC1 in primary progressive multiple sclerosis: Evidence of neuroprotection with amiloride

Neurodegeneration is the main cause for permanent disability in multiple sclerosis. The effect of current immunomodulatory treatments on neurodegeneration is insufficient. Therefore, direct neuroprotection and myeloprotection remain an important therapeutic goal. Targeting acid-sensing ion channel 1 (encoded by the ASIC1 gene), which contributes to the excessive intracellular accumulation of injurious Na+ and Ca2+ and is over-expressed in acute multiple sclerosis lesions, appears to be a viable strategy to limit cellular injury that is the substrate of neurodegeneration. While blockade of ASIC1 through amiloride, a potassium sparing diuretic that is currently licensed for hypertension and congestive cardiac failure, showed neuroprotective and myeloprotective effects in experimental models of multiple sclerosis, this strategy remains untested in patients with multiple sclerosis. In this translational study, we tested the neuroprotective effects of amiloride in patients with primary progressive multiple sclerosis. First, we assessed ASIC1 expression in chronic brain lesions from post-mortem of patients with progressive multiple sclerosis to identify the target process for neuroprotection. Second, we tested the neuroprotective effect of amiloride in a cohort of 14 patients with primary progressive multiple sclerosis using magnetic resonance imaging markers of neurodegeneration as outcome measures of neuroprotection. Patients with primary progressive multiple sclerosis underwent serial magnetic resonance imaging scans before (pretreatment phase) and during (treatment phase) amiloride treatment for a period of 3 years. Whole-brain volume and tissue integrity were measured with high-resolution T 1-weighted and diffusion tensor imaging. In chronic brain lesions of patients with progressive multiple sclerosis, we demonstrate an increased expression of ASIC1 in axons and an association with injury markers within chronic inactive lesions. In patients with primary progressive multiple sclerosis, we observed a significant reduction in normalized annual rate of whole-brain volume during the treatment phase, compared with the pretreatment phase (P = 0.018, corrected). Consistent with this reduction, we showed that changes in diffusion indices of tissue damage within major clinically relevant white matter (corpus callosum and corticospinal tract) and deep grey matter (thalamus) structures were significantly reduced during the treatment phase (P = 0.02, corrected). Our results extend evidence of the contribution of ASIC1 to neurodegeneration in multiple sclerosis and suggest that amiloride may exert neuroprotective effects in patients with progressive multiple sclerosis. This pilot study is the first translational study on neuroprotection targeting ASIC1 and supports future randomized controlled trials measuring neuroprotection with amiloride in patients with multiple sclerosis. © (2012) The Author

Influência do período de alimentação no consumo e ganho de peso do pirarucu Influence of feeding period on consumption and weight gain of pirarucu

O objetivo deste trabalho foi verificar o período preferencial de consumo alimentar do pirarucu, Arapaima gigas, e a influência de diferentes turnos de alimentação no consumo e ganho de peso dessa espécie. Foram testados três tratamentos: alimentação diurna (peixes alimentados às 9h e 15h), alimentação noturna (peixes alimentados às 21h e 3h) e alimentação contínua (peixes alimentados às 9h, 15h, 21h e 3h). Cada tratamento foi avaliado em triplicata, com cada unidade experimental formada por oito peixes, com peso médio de 313 g, estocados em tanques-redes de 1 m³ (1x1x1 m). Os nove tanques-redes foram alocados em um viveiro escavado de 120 m². O experimento durou 60 dias. A alimentação contínua promoveu maiores ganhos de peso e biomassa, taxa de crescimento específico e consumo total. Os tratamentos alimentação diurna e alimentação noturna apresentaram ganho de peso semelhante, porém, a alimentação diurna apresentou a melhor conversão alimentar. O período preferencial de alimentação do pirarucu foi o noturno, principalmente no começo da noite. Os dados deste estudo indicam que o horário de preferência alimentar não é o melhor horário de alimentação do pirarucu, em uma criação comercial. O período de alimentação mais indicado para a espécie, baseado na capacidade de conversão alimentar, é o diurno.<br>The objective of this study was to verify pirarucu Arapaima gigas preferential time of feeding, and the influence of different feeding periods on consumption and weight gain of this species. Three treatments were tested: diurnal feeding (fish fed at 9h and 15h), nocturnal feeding (fish fed at 21h and 3h), and continuous feeding (fish fed at 9h, 15h, 21h and 3h). Each treatment was evaluated in triplicate, and each trial unit had eight fishes with 313 g average weight, stoked into a 1 m³ (1x1x1 m) net cage. The nine net cages were located on a 120 m² earth pond. The trial lasted for 60 days. Continuous feeding promoted the highest weight and biomass gain, specific growth rate and feed consumption. Nocturnal and diurnal feeding treatments showed similar weight gain; however, diurnal feeding had the best feed conversion ratio. The preferred feeding time for pirarucu was the nocturnal period, mainly at the beginning of night. Data from this study indicated that the preferred feeding time is not the best one for feeding pirarucu on a commercial husbandry. The most indicated feeding period for this species, based on its feed conversion capacity, is diurnal period

Fish Diets in Aquaponics

Fish and feed waste provide most of the nutrients required by the plants in aquaponics if the optimum ratio between daily fish feed inputs and the plant growing area is sustained. Thus, the fish feed needs to fulfil both the fish’s and plant’s nutritional requirements in an aquaponic system. A controlled fish waste production strategy where the nitrogen, phosphorus and mineral contents of fish diets are manipulated and used provides a way of influencing the rates of accumulation of nutrients, thereby reducing the need for the additional supplementation of nutrients. To optimize the performance and cost-effectiveness of aquaponic production, fish diets and feeding schedules should be designed carefully to provide nutrients at the right level and time to complement fish, bacteria and plants. To achieve this, a species-specific tailor-made aquaponic feed may be optimized to suit the aquaponic system as a whole. The optimal point would be determined based on overall system performance parameters, including economic and environmental sustainability measures. This chapter thus focuses on fish diets and feed and reviews the state of the art in fish diets, ingredients and additives, as well as the nutritional/sustainable challenges that need to be considered when producing specific aquaponic feeds.peerReviewe