Whole-body protein metabolism in lactating and nonlactating women

The adaptive responses of body protein metabolism to lactation were characterized in women at 1, 5, and 12 mo postpartum and in nulliparous controls during a controlled diet of measured protein and energy intakes by nitrogen balance, a constant infusion of [13C]bicarbonate, and a primed constant infusion of [1-13C]leucine and [alpha-15N]-lysine. Dietary energy intakes in the lactating women were 27% greater than those in the nulliparous controls. Despite these differences, lactating women had significantly lower nitrogen balances compared with the nonlactating women (-4.0 +/- 37.8 vs. +44.7 +/- 30.8 mg.kg-1.day-1). No significant differences in amino acid flux, oxidation, or incorporation into protein were detected during fasting conditions in the two groups of women. However, significantly positive associations were noted between dietary intakes and the variables of protein metabolism in the lactating women. A more complete understanding of the mechanisms that regulate the disposition of dietary nutrients into maternal body stores or milk production will enhance the determination of nutrient requirements in lactating women.     

Influence of Nitrate and Sulfate on the Anaerobic Treatment of Pharmaceutical Wastewater

Anaerobic treatment of wastewater from the pharmaceutical industry, which contained about 3.2 g/L of sulfate, was carried out in an Upflow Anaerobic Sludge Blanket (UASB) reactor. After a startup period of 120 days, a chemical oxygen demand (COD) removal efficiency of more than 90 % was obtained along with an organic loading rate (OLR) of 1.5 g COD/(L day). During the same period, the sulfate removal was about 90 %. However, the performance of the reactor was affected when the loading rate was increased to 2.09 g COD/(L day). It was found that the accumulation of sulfides, combined with a decrease in the pH, affected the reactor performance. In batch reactor studies with pharmaceutical wastewater it was observed that methane production began only after the initiation of nitrate consumption. The denitrification process can inhibit sulfate reduction at high nitrate concentrations, but compared to reactors without nitrate, the sulfate reduction process and sulfide formation were quickly initiated at low nitrate concentrations. The methanogenic activity was however affected by the presence of more than 2 g/L of sulfate.     

Simulating the Distribution of Individual Livestock Farms and Their Populations in the United States: An Example Using Domestic Swine (Sus scrofa domesticus) Farms

Livestock distribution in the United States (U.S.) can only be mapped at a county-level or worse resolution. We developed a spatial microsimulation model called the Farm Location and Agricultural Production Simulator (FLAPS) that simulated the distribution and populations of individual livestock farms throughout the conterminous U.S. Using domestic pigs (Sus scrofa domesticus) as an example species, we customized iterative proportional-fitting algorithms for the hierarchical structure of the U.S. Census of Agriculture and imputed unpublished state- or county-level livestock population totals that were redacted to ensure confidentiality. We used a weighted sampling design to collect data on the presence and absence of farms and used them to develop a national-scale distribution model that predicted the distribution of individual farms at a 100 m resolution. We implemented microsimulation algorithms that simulated the populations and locations of individual farms using output from our imputed Census of Agriculture dataset and distribution model. Approximately 19% of county-level pig population totals were unpublished in the 2012 Census of Agriculture and needed to be imputed. Using aerial photography, we confirmed the presence or absence of livestock farms at 10,238 locations and found livestock farms were correlated with open areas, cropland, and roads, and also areas with cooler temperatures and gentler topography. The distribution of swine farms was highly variable, but cross-validation of our distribution model produced an area under the receiver-operating characteristics curve value of 0.78, which indicated good predictive performance. Verification analyses showed FLAPS accurately imputed and simulated Census of Agriculture data based on absolute percent difference values of < 0.01% at the state-to-national scale, 3.26% for the county-to-state scale, and 0.03% for the individual farm-to-county scale. Our output data have many applications for risk management of agricultural systems including epidemiological studies, food safety, biosecurity issues, emergency-response planning, and conflicts between livestock and other natural resources.     

Detection of a novel stem cell probably involved in normal turnover of the lung airway epithelium

Regeneration of the lung airway epithelium after injury has been extensively studied. In contrast, analysis of its turnover in healthy adulthood has received little attention. In the classical view, this epithelium is maintained in the steady‐state by the infrequent proliferation of basal or Clara cells. The intermediate filament protein nestin was initially identified as a marker for neural stem cells, but its expression has also been detected in other stem cells. Lungs from CD1 mice at the age of 2, 6, 12, 18 or 24 months were fixed in neutral‐buffered formalin and paraffin‐embedded. Nestin expression was examined by an immunohistochemical peroxidase‐based method. Nestin‐positive cells were detected in perivascular areas and in connective tissue that were in close proximity of the airway epithelium. Also, nestin‐positive cells were found among the cells lining the airway epithelium. These findings suggest that nestin‐positive stem cells circulate in the bloodstream, transmigrate through blood vessels and localize in the lung airway epithelium to participate in its turnover. We previously reported the existence of similar cells able to differentiate into lung chondrocytes. Thus, the stem cell reported here might be a bone marrow‐derived mesenchymal stem cell (BMDMSC) able to generate several types of lung tissues. In conclusion, our findings indicate that there exist a BMDMSC in healthy adulthood that participates in the turnover of the lung airway epithelium. These findings may improve our knowledge about the lung stem cell biology and also provide novel approaches to therapy for devastating pulmonary diseases.     

The socioecological complexity of ecological restoration in Mexico

Almost half of Mexican territory has been classified as environmentally degraded. The main response for the last 60 years has been reforestation to combat soil erosion and loss of forest cover, mostly carried out on private lands where negotiations with local stakeholders were critical. Despite four legal instruments referring to ecological restoration, no specific instrument that defines basic concepts, criteria and standards, required actions, or regulations to implement and evaluate ecological restoration exists. The Ministry of the Environment and Natural Resources is now solely in charge of restoration and only recently have external scientists been invited to be part of the process. Following important national and international events in Latin America and the Caribbean region, the First Mexican Symposium on Ecological Restoration was held in November, 2014. This historic event was the first action undertaken in Mexico to meet Objective 3 of the Global Strategy of Plant Conservation, coordinated in Mexico by the National Council for the Use and Knowledge of Biodiversity. Although mangrove ecosystems are the most endangered ecosystem type in Mexico, they were not well represented at the symposium. In contrast, several other ecosystem types, such as tropical dry forest and islands, have received increased attention. Overall, while the Symposium and above‐cited policy initiatives are important steps, Mexico needs to increase its institutional capacities and social organization of the rural sector with regard to ecological restoration. Better integration of social and natural scientists and increased participation of Mexico internationally is also needed.