The significance of nitrogen fixation to new production during early summer in the Baltic Sea.

Rates of dinitrogen (N2) fixation and primary production were measured during two 9 day transect cruises in the Baltic proper in June–July of 1998 and 1999. Assuming that the early phase of the bloom of cyanobacteria lasted a month, total rates of N2 fixation contributed 15 mmol N m−2 (1998) and 33 mmol N m−2 (1999) to new production (sensu Dugdale and Goering, 1967). This constitutes 12–26% more new N than other annual estimates (mid July–mid October) from the same region. The between-station variability observed in both total N2 fixation and primary productivity greatly emphasizes the need for multiple stations and seasonal sampling strategies in biogeochemical studies of the Baltic Sea. The majority of new N from N2 fixation was contributed by filamentous cyanobacteria. On average, cyanobacterial cells >20 µm were able to supply a major part of their N requirements for growth by N2 fixation in both 1998 (73%) and 1999 (81%). The between-station variability was high however, and ranged from 28–150% of N needed to meet the rate of C incorporation by primary production. The molar C:N rate incorporation ratio (C:NRATE) in filamentous cyanobacterial cells was variable (range 7–28) and the average almost twice as high as the Redfield ratio (6.6) in both years. Since the molar C:N mass ratio (C:NMASS) in filamentous cyanobacterial cells was generally lower than C:NRATE at a number of stations, we suggest that the diazotrophs incorporated excess C on a short term basis (carbohydrate ballasting and buoyancy regulation), released nitrogen or utilized other regenerated sources of N nutrients. Measured rates of total N2 fixation contributed only a minor fraction of 13% (range 4–24) in 1998 and 18% (range 2–45) in 1999 to the amount of N needed for the community primary production. An average of 9 and 15% of total N2 fixation was found in cells <5 µm. Since cells <5 µm did not show any detectable rates of N2 fixation, the 15N-enrichment could be attributed to regenerated incorporation of dissolved organic N (DON) and ammonium generated from larger diazotroph cyanobacteria. Therefore, N excretion from filamentous cyanobacteria may significantly contribute to the pool of regenerated nutrients used by the non-diazotroph community in summer. Higher average concentrations of regenerated N (ammonium) coincided with higher rates of N2 fixation found during the 1999 transect and a higher level of 15N-enrichment in cells <5 µm. A variable but significant fraction of total N2 fixation (1–10%) could be attributed to diazotrophy in cells between 5–20 µm

Effects of transcranial direct current stimulation on neural networks in young and older adults

Transcranial direct current stimulation (tDCS) may be a viable tool to improve motor and cognitive function in advanced age. However, although a number of studies have demonstrated improved cognitive performance in older adults, other studies have failed to show restorative effects. The neural effects of beneficial stimulation response in both age groups is lacking. In the current study, tDCS was administered during simultaneous fMRI in 42 healthy young and older participants. Semantic word generation and motor speech baseline tasks were used to investigate behavioral and neural effects of uni-and bihemispheric motor cortex tDCS in a three-way, crossover, sham tDCS controlled design. Independent components analysis assessed differences in task-related activity between the two age groups and tDCS effects. at the network level. We also explored whether laterality of language network organization was effected by tDCS. Behaviorally, both active tDCS conditions significantly improved semantic word retrieval performance in young and older adults and were comparable between groups and stimulation conditions. Network-level tDCS effects were identified in the ventral and dorsal anterior cingulate networks in the combined sample during semantic fluency and motor speech tasks. In addition, a shift toward enhanced left laterality was identified in the older adults for both active stimulation conditions. Thus, tDCS results in common network-level modulations and behavioral improvements for both age groups, with an additional effect of increasing left laterality in older adults

Online monitoring the isomerization of an azobenzene-based dendritic bolaamphiphile using ion mobility-mass spectrometry

Ion mobility-mass spectrometry was used to obtain detailed information about the kinetics of the light-induced cis/trans isomerization process of a new supramolecular azobenzene-based bolaamphiphile. Further experiments revealed that the investigated light-induced structural transition dramatically influences the aggregation behaviour of the molecule

Produção de morangos em sistema semi-hidropônico sob diferentes substratos.

O morango (Fragaria ananassa Duch) é uma fruta de grande aceitação no mercado nacional. As principais regiões produtoras desta fruta encontram-se nos Estados do Rio Grande do Sul, São Paulo e Minas Gerais. No Rio Grande do Sul o cultivo concentra-se na região do Vale do Cai e Pelotas, porém encontra-se em ascensão a produção na região dos Campos de Cima da Serra. O morangueiro é uma planta que se adapta bem a diferentes regiões e sistemas de cultivo, Pode ser cultivado no solo, com ou sem cobertura plástica, em túneis baixos ou em estufas, ou no sistema hidropônico, com ou sem substrato. O sistema hidropônico pode ser conduzido com e sem substrato, este último conhecido como sistema semi-hidropônico. A fertirrigação proporciona a oferta de nutrientes diretamente ao sistema radicular das plantas, conforme as necessidades das mesmas. A casca de arroz é o substrato mais utilizado no sistema de produção de morangos semi-hidropônicos, pois apresenta características físicas e químicas estáveis tornando-se assim mais resistente à decomposição, porém apresenta alta porosidade, o que exige uma mistura com outros substratos que neutralizem esse efeito. O presente trabalho teve como objetivo avaliar diferentes tipos de substratos, compostos por casca de arroz, em duas cultivares de morangueiro

Composição mineral de maçãs 'Gala' produzidas em Vacaria-RS e São Joaquim-SC na safra 2012/13.

Este trabalho teve por objetivo determinar a composição mineral de frutos de macieira da cultivar Gala, produzidos em Vacaria-RS e São Joaquim-SC, na safra 2012-2013

Efeito da irrigação e fertirrigação no volume de poda de inverno das cultivares Galaxy e Fuji Suprema na safra 2021/2022.

A poda de inverno é uma técnica de manejo essencial na cultura da macieira para garantir a eficiência produtiva. O objetivo deste trabalho foi avaliar os efeitos da irrigação e fertirrigação no volume de poda das cultivares Galaxy e Fuji Suprema

Passenger car data – a new source of real-time weather information for nowcasting, forecasting, and road safety

Presentación realizada en la 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

Eficiência da irrigação e fertirrigação na produção de frutos das cultivares Galaxy e Fuji Suprema na safra 2021/2022.

A evolução do setor da maçã requer práticas para aumentar a produtividade e qualidade do produto, sendo a fertirrigação uma alternativa de manejo para promover esta evolução produtiva. Essa prática consiste no fornecimento de nutrientes que a planta necessita por meio de fertilizantes postos na água utilizada para irrigação.O objetivo deste trabalho foi avaliar a eficiência da irrigação e da fertirrigação na produção de frutos das cultivares Galaxy e Fuji Suprema