No abstract

The 450 Scenario, which limits the increase in global average temperature to 2 ºC, makes it necessary to take steps towards a low-carbon economy. Since the energy sector is a major contribution to anthropogenic greenhouse gas (GHG) emissions, the production of biofuels can play a key role in strategies aimed at climate change mitigation. In this regard, the oil derived from macauba palm (Acrocomia aculeata), mainly constituted of saturated organic chains, has been claimed to hold promise for the production of liquid fuels. The high potential yield, diversity of co-products and various positive features of this emerging energy crop make it an interesting option both from a social and an environmental point of view. Nonetheless, a full environmental evaluation is still missing. In the study presented herein, the impacts produced in its plantation, cultivation and harvesting phases and the associated cumulative energy demand P r e p r i n t 2 have been determined using a life cycle analysis methodology, in addition to shedding some light on its GHG intensity relative to the other energy crops it can displace. Excluding land use changes and biogenic CO 2 fixed by the crop, it was concluded that to produce one ton of macauba fruit in Brazil, the system would absorb 1810.21 MJ, with GHG emissions of 158.69 kg CO 2 eq in the 20-year timeframe, and of 140.04 kg CO 2 eq in the 100-year timeframe (comparable to those of African oil palm). Damage to human health, ecosystem quality, and resources would add up to 16 Pt•t-1 according to Eco-indicator 99 methodology. In order to account for the uncertainty derived from improvement and domestication programs, which should affect current production levels, a sensitivity analysis for different productivities was performed. In all analyses, fertilization was found to be responsible for ca. 90% of the impacts, and hence special attention should be paid to the development of alternative fertilizer management schemes.

Simulation of macauba palm cultivation: an energy-balance and greenhouse gas emissions analysis The expansion of the production and use of bioenergy is deemed as one of the most efficient mechanisms to reduce greenhouse gas (GHG) emissions. Nevertheless, the environmental impact of the production processes for many raw materials remains unexplored. Several studies have pointed to macauba palm (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) as a promising species for biofuel production in the tropics, but investigations on the environmental benefits of the cultivation of this palm as a source of raw material for biofuel production have not been reported so far. The aim of this work has been to conduct an analysis of macauba production system in terms of GHG emissions and CO 2 uptake for a productive cycle, considering a 30-year horizon. The energy conversion efficiency (energy outputs/inputs ratio) per unit area of land has been put in relationship with crop productivity and related to the dilution effect of production inputs. Results of the simulation estimate that GHG emissions from macauba crop would be around 180 Mg CO 2 eq•ha-1 , whereas CO 2 fixation during cultivation would range from 796 to 1137 Mg CO 2 eq•ha-1. The energy assessment shows that the net energy balance for macauba crop would reach 512.3 GJ•ha-1 and that the energy efficiency would be ca. 24.2 GJ•GJ-1. These results, compared with those of traditional energy crops such as sugarcane, oil palm, sunflower, corn or jatropha, suggest that macauba crop may have the potential to outperform them in terms of efficiency. The domestication and exploitation in extensive farming of this species as an agroforestry crop, although still at an early stage, has a bright future.

Transition metal oxides and chalcogenides have recently attracted great attention as the next generation of 2-D materials due to their unique electronic and optical properties. In this study, a new procedure for the obtaining of highly crystalline α-MoO3 is proposed as an alternative to vapor-phase synthesis. In this approach, a first reaction between molybdate, citrate and thiourea allowed to obtain MoS2, which—upon calcination at a temperature of 650 °C in the presence of g-C3N4—resulted in MoO3 with a definite plate-like shape. The colorless (or greenish) α-MoO3 nanoplates obtained with this procedure featured a multilayer stack structure, with a side-length of 1–2 μm and a thickness of several nanometers viewed along the [010] direction. The nucleation-growth of the crystal can be explained by a two-dimensional layer-by-layer mechanism favored by g-C3N4 lamellar template.

Serum steroid profiles were investigated in order to evaluate the potential use of circulating sex steroid levels as a tool for sex identification in brown trout. Changes in the serum concentrations of testosterone (T), progesterone (P), 17-β-estradiol (E2), and cortisol (F) in wild and farmed mature female and male brown trout, Salmo trutta L., were measured in each season (January, May, July, and October) in six rivers and four hatcheries located in the north-west of Spain. Serum cortisol levels in farmed brown trout were significantly higher and showed a seasonal pattern opposite to that found in wild trout. Because levels of the hormones under study can be affected by disruptive factors such as exposure to phytoestrogens (which alters the hypothalamic-pituitary-gonadal axis) and infection with Saprolegnia parasitica (which alters the hypothalamic-pituitary-adrenal axis), both factors are taken into account.