72 research outputs found

    Long-line culture of red seaweed in the Pacific Northwest

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    The goal of this study was to adapt open-water rope culture techniques to the native red seaweed Devaleraea mollis to support a new seaweed aquaculture industry in Humboldt Bay, California. The specific objectives for this study were to: 1) evaluate the growth of D. mollis cultivated at different depths and seasons (fall/winter, spring/summer), 2) estimate nutrients removed by D. mollis from the water, and 3) measure heavy metals and pesticides to determine potential health risk upon ingestion. Bundles of seaweed were inserted into 3 m long weighted vertical lines attached to two horizontal long-lines suspended by floats. Two four-month trials (September to December 2020 and April to July 2021) were compared. Long-lines in Trial 1 were seeded on the same date, and data was pooled from both long-lines. Data was analyzed separately for each long line in Trial 2 as the lines were seeded on different dates. Both depth (p\u3c0.001) and month (p\u3c0.002, two-way ANOVA, Tukey HSD test) had significant effects on wet weight for the first trial with depths 0 m and 1 m and months November and December producing the best growth. For Trial 2 only depth was significant (p=0.006) for long-line 1 with the 0 m depth producing the best growth while both depth (p\u3c0.001) and month (p=0.006) significantly affected wet weight for long-line 2 with 0 m and the month of May producing the best growth. Maximum growth rate from Trial 1 was 0.21 g/day, and 0.19 g/day from Trial 2. A total of 1.20 kg of carbon, 0.12 kg of nitrogen, and 0.02 kg of phosphorus were removed from the water by the seaweed produced in this study. All pesticides were found to be undetectable, and all heavy metals were either undetectable or below action levels with the exception of manganese for 3 m in Trial 1 and 2 m and 3 m in Trial 2 (21.0 mg/kg, 77.6 mg/kg, 93.3 mg/kg respectively). Results from this study suggest optimal growth occurs in the winter and early spring at no more than 1 m in depth, D. mollis’s potential for nutrient bioextraction, and that D. mollis grown in Humboldt Bay poses low risk to consumers for heavy metals and pesticides

    Feeding and Care of Calves

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    It is not infrequent that considerable difficulty is encountered in raising calves with limited amounts of milk or none at all. Requests for information on calf gruels, mixed grain feeds, and commercial supplements are frequent enough to make a short circular upon this subject seem desirable. Furthermore, as the more diversified agricultural program gets under way these requests are increasmg

    CCN activity and organic hygroscopicity of aerosols downwind of an urban region in central Amazonia: Seasonal and diel variations and impact of anthropogenic emissions

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    During the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign, size-resolved cloud condensation nuclei (CCN) spectra were characterized at a research site (T3) 60 km downwind of the city of Manaus, Brazil, in central Amazonia for 1 year (12 March 2014 to 3 March 2015). Particle hygroscopicity (ÎșCCN) and mixing state were derived from the size-resolved CCN spectra, and the hygroscopicity of the organic component of the aerosol (Îșorg) was then calculated from ÎșCCN and concurrent chemical composition measurements. The annual average ÎșCCN increased from 0.13 at 75 nm to 0.17 at 171 nm, and the increase was largely due to an increase in sulfate volume fraction. During both wet and dry seasons, ÎșCCN, Îșorg, and particle composition under background conditions exhibited essentially no diel variations. The constant Îșorg of -1/4 0. 15 is consistent with the largely uniform and high O : C value (-1/4 0. 8), indicating that the aerosols under background conditions are dominated by the aged regional aerosol particles consisting of highly oxygenated organic compounds. For air masses strongly influenced by urban pollution and/or local biomass burning, lower values of Îșorg and organic O : C atomic ratio were observed during night, due to accumulation of freshly emitted particles, dominated by primary organic aerosol (POA) with low hygroscopicity, within a shallow nocturnal boundary layer. The O : C, Îșorg, and ÎșCCN increased from the early morning hours and peaked around noon, driven by the formation and aging of secondary organic aerosol (SOA) and dilution of POA emissions into a deeper boundary layer, while the development of the boundary layer, which leads to mixing with aged particles from the residual layer aloft, likely also contributed to the increases. The hygroscopicities associated with individual organic factors, derived from PMF (positive matrix factorization) analysis of AMS (aerosol mass spectrometry) spectra, were estimated through multivariable linear regression. For the SOA factors, the variation of the Îș value with O : C agrees well with the linear relationship reported from earlier laboratory studies of SOA hygroscopicity. On the other hand, the variation in O : C of ambient aerosol organics is largely driven by the variation in the volume fractions of POA and SOA factors, which have very different O : C values. As POA factors have hygroscopicity values well below the linear relationship between SOA hygroscopicity and O : C, mixtures with different POA and SOA fractions exhibit a steeper slope for the increase in Îșorg with O : C, as observed during this and earlier field studies. This finding helps better understand and reconcile the differences in the relationships between Îșorg and O : C observed in laboratory and field studies, therefore providing a basis for improved parameterization in global models, especially in a tropical context

    Influence of urban pollution on the production of organic particulate matter from isoprene epoxydiols in central Amazonia

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    The atmospheric chemistry of isoprene contributes to the production of a substantial mass fraction of the particulate matter (PM) over tropical forests. Isoprene epoxydiols (IEPOX) produced in the gas phase by the oxidation of isoprene under HO2-dominant conditions are subsequently taken up by particles, thereby leading to production of secondary organic PM. The present study investigates possible perturbations to this pathway by urban pollution. The measurement site in central Amazonia was located 4 to 6 h downwind of Manaus, Brazil. Measurements took place from February through March 2014 of the wet season, as part of the GoAmazon2014/5 experiment. Mass spectra of organic PM collected with an Aerodyne Aerosol Mass Spectrometer were analyzed by positive-matrix factorization. One resolved statistical factor (IEPOX-SOA factor) was associated with PM production by the IEPOX pathway. The IEPOX-SOA factor loadings correlated with independently measured mass concentrations of tracers of IEPOX-derived PM, namely C5-alkene triols and 2-methyltetrols (R = 0. 96 and 0.78, respectively). The factor loading, as well as the ratio f of the loading to organic PM mass concentration, decreased under polluted compared to background conditions. For an increase in NOy concentration from 0.5 to 2 ppb, the factor loading and f decreased by two to three fold. Overall, sulfate concentration explained 37 % of the variability in the factor loading. After segregation of factor loading into subsets based on NOy concentration, the sulfate concentration explained up to 75 % of the variability. Considering both factors, the data sets show that the suppressing effects of increased NO concentrations dominated over the enhancing effects of higher sulfate concentrations. The pollution from Manaus elevated NOy concentrations more significantly than sulfate concentrations relative to background conditions. In this light, increased emissions of nitrogen oxides, as anticipated for some scenarios of Amazonian economic development, could significantly alter pathways of PM production that presently prevail over the tropical forest, implying changes to air quality and regional climate.</html

    Molecular Cause and Functional Impact of Altered Synaptic Lipid Signaling Due to a \u3cem\u3eprg-1\u3c/em\u3e Gene SNP

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    Loss of plasticity‐related gene 1 (PRG‐1), which regulates synaptic phospholipid signaling, leads to hyperexcitability via increased glutamate release altering excitation/inhibition (E/I) balance in cortical networks. A recently reported SNP in prg‐1 (R345T/mutPRG‐1) affects ~5 million European and US citizens in a monoallelic variant. Our studies show that this mutation leads to a loss‐of‐PRG‐1 function at the synapse due to its inability to control lysophosphatidic acid (LPA) levels via a cellular uptake mechanism which appears to depend on proper glycosylation altered by this SNP. PRG‐1+/− mice, which are animal correlates of human PRG‐1+/mut carriers, showed an altered cortical network function and stress‐related behavioral changes indicating altered resilience against psychiatric disorders. These could be reversed by modulation of phospholipid signaling via pharmacological inhibition of the LPA‐synthesizing molecule autotaxin. In line, EEG recordings in a human population‐based cohort revealed an E/I balance shift in monoallelic mutPRG‐1 carriers and an impaired sensory gating, which is regarded as an endophenotype of stress‐related mental disorders. Intervention into bioactive lipid signaling is thus a promising strategy to interfere with glutamate‐dependent symptoms in psychiatric diseases

    The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges

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    Feeding and Care of Calves

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    It is not infrequent that considerable difficulty is encountered in raising calves with limited amounts of milk or none at all. Requests for information on calf gruels, mixed grain feeds, and commercial supplements are frequent enough to make a short circular upon this subject seem desirable. Furthermore, as the more diversified agricultural program gets under way these requests are increasmg

    Studies of Rickets in Swine

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    During the years 1925 to 1929 inclusive, the Nebraska Agricultural Experiment Station carried on a series of four experiments to study the importance of the antirachitic factors in the nutrition of swine. Vitamin D as obtained from cod-liver oil and the radiant-energy factor of sunlight were the sources of the antirachitic factors that received primary consideration. Emphasis was placed upon the study of the symptoms and lesions produced in pigs fed a rickets-producing ration
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