The structure and dynamics of young star clusters: King 16, NGC 1931, NGC 637 and NGC 189

In this paper, using 2MASS photometry, we study the structural and dynamical properties of four young star clusters viz. King 16, NGC 1931, NGC 637 and NGC 189. For the clusters King 16, NGC 1931, NGC 637 and NGC 189, we obtain the limiting radii of 7', 12', 6' and 5' which correspond to linear radii of 3.6 pc, 8.85 pc, 3.96 pc and 2.8 pc respectively. The reddening values $E(B-V)$ obtained for the clusters are 0.85, 0.65--0.85, 0.6 and 0.53 and their true distances are 1786 pc, 3062 pc, 2270 pc and 912 pc respectively. Ages of the clusters are 6 Myr, 4 Myr, 4 Myr and 10 Myr respectively. We compare their structures, luminosity functions and mass functions ($\phi(M) = dN/dM \propto M^{-(1+\chi)}$) to the parameter $\tau = t_{age}/t_{relax}$ to study the star formation process and the dynamical evolution of these clusters. We find that, for our sample, mass seggregation is observed in clusters or their cores only when the ages of the clusters are comparable to their relaxation times ($\tau \geq 1$). These results suggest mass seggregation due to dynamical effects. The values of $\chi$, which characterise the overall mass functions for the clusters are 0.96 $\pm$ 0.11, 1.16 $\pm$ 0.18, 0.55 $\pm$ 0.14 and 0.66 $\pm$ 0.31 respectively. The change in $\chi$ as a function of radius is a good indicator of the dynamical state of clusters.Comment: Accepted for publication in Astrophysics & Space Scienc

Chemometric characterization of gamma irradiated chestnuts from Turkey

Chestnut (Castanea sativa Miller) is a valuable natural resource, with high exportation levels. Due to their water content, chestnuts are susceptible to storage problems like dehydration or development of insects and microorganisms. Irradiation has been revealing interesting features to be considered as an alternative conservation technology, increasing food products shelf-life. Any conservation methodology should have a wide application range. Hence, and after evaluating Portuguese cultivars, the assessment of irradiation effects in foreign cultivars might act as an important indicator of the versatility of this technology. In this work, the effects of gamma irradiation (0.0, 0.5 and 3.0 kGy) on proximate composition, sugars, fatty acids (FA) and tocopherols composition of Turkish chestnuts stored at 4 ºC for different periods (0, 15 and 30 days) were evaluated. Regarding proximate composition, the storage time (ST) had higher influence than irradiation dose (ID), especially on fat, ash, carbohydrates and energetic value. Sucrose exhibited similar behavior in response to the assayed ST and ID. The prevalence of ST influence was also verified for FA, tocopherols and sucrose. Lauric, palmitoleic and linolenic acids, were the only FA that undergone some differences with ID. Saturated, monounsaturated and polyunsaturated fatty acids levels were not affected neither by storage nor irradiation. α-Tocopherol was the only vitamer with significant differences among the assayed ST and ID. Overall, Turkish cultivars showed a compositional profile closely related with Portuguese cultivars, and seemed to confirm that gamma irradiation in the applied doses did not change chestnut chemical and nutritional composition

Gamma irradiation improves the nutritional profile of dried and sliced wild Boletus edulis Bull.

Boletus edulis Bull. is a seasonal mushroom with high perishability (shelf-life: 1-3 days at room temperature) [1]. Drying is a widely used postharvest technology, which overcomes those problems. Nevertheless, after slicing, mushrooms need special care to keep their quality [2]. A possible treatment is applying ionizing radiation. Herein, the effects of gamma irradiation (2, 6 and 10 kGy) on nutritional parameters were analyzed in wild B. edulis dried and sliced samples (Bragança, Northeast of Portugal, 2013). Irradiation was performed at Gamma-Pak Sterilizasyon (Çerkezköy, Turkey). The nutritional parameters were determined throughout the storage time (0, 6 and 12 months) according to official procedures. The results were compared considering the mean value of each storage time (ST), including all gamma irradiation (GI) doses, and also the mean value of each dose, with all ST included, allowing verifying the effect of each factor independently. Despite the detected significance in the interaction among ST and GI for all assayed factors, some defined conclusions were obtained: fat, protein and ash contents gave maximal contents in samples irradiated with 10 kGy, while the lowest values were detected in non-irradiated samples. Regarding the effect of ST, these same parameters presented minimal values in samples stored during 12 months. The variation in carbohydrates, which was calculated by difference, was precisely the opposite of the previously described. The variation in energy was less pronounced for both effects. Overall, irradiation treatment, particularly the 10 kGy dose, tended to improve the nutritional profile of sliced-dried B. edulis samples. References [1] Jaworska, G., Bernaś, E. (2009). Food Chemistry, 113, 936-943. [2] Oliveira, F., Sousa-Gallagher, M. J., Mahajan, P. V., & Teixeira, J. A. (2012). Journal of Food Engineering, 108, 507–514.FCT and COMPETE/QREN/UE- strategic projects PEst-OE/AGR/UI0690/2014 (CIMO) and PEst-C/EQB/LA0006/2014 (REQUIMTE); grants SFRH/BD/76019/2011 and SFRH/BPD/72802/2010 to A. Fernandes and J.C.M. Barreira, respectively

Effect of gamma irradiation and extended storage on selected chemical constituents and antioxidant activities of sliced mushroom

Due to its exquisite odor and taste, Boletus edulis Bull.: Fr. mushroom is being increasingly used throughout the world. However, the availability of this product is highly restrained by its seasonality and perishability, demanding special care to keep its quality. Furthermore, mushrooms are often distributed in sliced form, and the slicing operation requires special treatments, besides augmenting the possibility of microbial contamination. Some techniques are currently applied to sliced mushrooms, but these processes had adverse effects on nutrients, odor, texture and taste, besides requiring expensive equipment. Food irradiation is being studied as an alternative technology to improve the quality and durability of determined products, having been previously applied in several mushroom species. Herein, gamma irradiation was applied to dried and sliced samples of B. edulis, at high doses (2, 6 and 10 kGy), and the effects on nutritional, chemical and antioxidant parameters were evaluated throughout storage (6 and 12 months). The results obtained for the chemical parameters do not advised storing B. edulis for such extended periods, since some relevant changes were detected, especially in samples stored for 12 months. In general, the gamma irradiation treatment did not cause further changes in the chemical composition, besides having a slightly positive effect in keeping the antioxidant activity and most of the bioactive compounds profiled in this work, contributing to maintain the potential health effects of this exquisite food, even after extended storage periods.The authors are grateful to the Foundation for Science and Technology, COMPETE/QREN/EU - strategic projects PEst-OE/AGR/UI0690/2014 (CIMO) and PEst-C/EQB/LA0006/2014 (REQUIMTE), FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement (PT2020UID/QUI/50006/2013 - POCI/01/0145/FERDER/007265). A. Fernandes and J.C.M. Barreira thank FCT for their grants SFRH/BD/76019/2011 and SFRH/BPD/72802/2010, respectively.info:eu-repo/semantics/publishedVersio

Long-term experimental evolution decouples size and production costs in Escherichia coli

Body size covaries with population dynamics across life’s domains. Metabolism may impose fundamental constraints on the coevolution of size and demography, but experimental tests of the causal links remain elusive. We leverage a 60,000-generation experiment in which Escherichia coli populations evolved larger cells to examine intraspecific metabolic scaling and correlations with demographic parameters. Over the course of their evolution, the cells have roughly doubled in size relative to their ancestors. These larger cells have metabolic rates that are absolutely higher, but relative to their size, they are lower. Metabolic theory successfully predicted the relations between size, metabolism, and maximum population density, including support for Damuth’s law of energy equivalence, such that populations of larger cells achieved lower maximum densities but higher maximum biomasses than populations of smaller cells. The scaling of metabolism with cell size thus predicted the scaling of size with maximum population density. In stark contrast to standard theory, however, populations of larger cells grew faster than those of smaller cells, contradicting the fundamental and intuitive assumption that the costs of building new individuals should scale directly with their size. The finding that the costs of production can be decoupled from size necessitates a reevaluation of the evolutionary drivers and ecological consequences of biological size more generally.Dustin J. Marshall, Martino Malerba, Thomas Lines, Aysha L. Sezmis, Chowdhury M. Hasan, Richard E. Lenski, and Michael J. McDonal

Chemometric characterization of gamma irradiated chestnuts from Turkey

Chestnuts (Castanea sativa Miller) is a valuable natural resource, with high exportation levels. Due to their water content, chestnuts are susceptible to storage problems like dehydration or development of insects and microorganisms. Irradiation has been revealing promising features to be considered as an alternative conservation technology, for Portugese cultivars. Hence, the assessment of irradiation effects in foreign cultivars might act as an important indicator of the versatility of this technology. In this work, the effects of gamma irradiation (0.0, 0.5 and 3.0 kGy) on proximate composition, sugars, fatty acids and tocopherols composition of Turkish chestnuts stored at 4 ºC for different periods (0, 15 and 30 days) was evaluated. Regarding proximate composition, the storage time (ST) had higher influence than irradiation dose (ID), especially on fat, ash, carbohydrates and energetic value. Sucrose exhibited similar behavior in response to the assayed ST and ID. The prevalence of ST influence was also verified for fatty acids (FA), tocopherols and sucrose. Lauric, palmitoleic and linolenic acids, were the only FA that undergone some differences with ID. Saturated, monounsaturated and polyunsaturated fatty acids levels were not affected neither by storage nor irradiation. α-Tocopherol was the only vitamer with significant differences among the assayed ST and ID. Overall, our results confirm that gamma-irradiation is a promising conservation methodology, without inducing changes in chestnut chemical and nutritional composition

Influência da dose de radiação gama na cor de castanhas de origem Portuguesa e Turca (Castanea sativa Mill.)

A produção mundial de castanha está estimada em 1,1 milhões de toneladas, distribuídas por uma superfície de aproximadamente 340 000 ha, contribuindo a Europa em cerca de 12% dessa produção. Portugal assume um papel importante, contribuindo com aproximadamente 3%. Contudo, só cerca de 15% da produção Portuguesa é absorvida pelo mercado nacional, sendo os restantes 85% exportados. Estes valores demonstram a importância que este fruto tem para o equilíbrio da balança comercial Portuguesa. Durante a conservação da castanha, os produtores e industriais do sector enfrentam diversos problemas, tais como: I) Perda de peso, resultado da elevada taxa de transpiração que este fruto apresenta, a qual acarreta importantes perdas económicas e de qualidade; II) Infestação por insectos, tais como o bichado e o gorgulho; e III) Desenvolvimento de fungos, alguns dos quais produtores de micotoxinas. Até há pouco tempo, a fumigação com brometo de metilo era uma das técnicas mais utilizadas para eliminar pragas, sendo utilizada em castanha para exportação. Contudo, este composto, por ser um agente tóxico de largo espectro, pode causar efeitos nocivos na saúde humana. Por outro lado, o Protocolo de Montreal, o qual Portugal subscreveu, declarou este produto como nocivo para a camada de ozono, tendo dado início a um procedimento para a sua eliminação. Por tal, a implementação de métodos alternativos assume assim particular importância. Neste contexto, o tratamento por irradiação surge como uma técnica possível a aplicar no futuro próximo, estando autorizado por entidades oficiais o uso de radiação gama (60Co e 137Cs), feixes de electrões e raios-X. A irradiação como técnica de conservação tem sido testada com sucesso em diversos produtos alimentares, tais como mangas, morangos, etc., e encontra-se regulamentada pela União Europeia (UE) através da Directiva (CE) nº 1999/2/EC. Contudo, elevadas doses de radiação gama podem afectar a integridade funcional de algumas biomoléculas, originando alterações nos produtos, o que obriga a um estudo de adequabilidade para cada alimento em particular. De forma a obter mais informação sobre o efeito do uso da radiação gama, como técnica de conservação em castanhas (Castanea sativa), no presente trabalho pretendeu-se estudar a influência da dose de radiação sobre a cor de frutos sujeitos a esse tratamento, tanto a nível exterior (fruto com casca) como interior (fruto sem película e fruto cortado), por se tratar de um parâmetro de grande importância para a futura aceitabilidade do produto por parte do consumidor. Adicionalmente, pretendeu-se verificar se os resultados obtidos eram ou não semelhantes ao utilizar castanha, Castanea sativa, proveniente da Turquia, a qual é um dos principais produtores mundiais deste fruto. De forma a atingir os objectivos propostos, castanhas (Castanea sativa) de origem Portuguesa foram irradiadas com doses de 0,25; 0,50; 1,0 e 3,0 kGy a um débito de dose de 0,8 kGy.h-1, usando uma câmara de radiação gama com quatro fontes de 60Co. As irradiações foram realizadas em triplicado. Após tratamento, as amostras foram armazenadas sob refrigeração (5 a 6ºC) e analisadas aos 0, 15 e 30 dias de armazenamento. Em simultâneo, foram processadas castanhas não sujeitas a qualquer tratamento (controlo). Para cada dose e tempo de armazenamento, a cor foi avaliada através de um colorímetro, tendo sido determinados os parâmetros de cor de Hunter (L, a, b). Estes parâmetros foram também determinados em castanhas tratadas com o mesmo tipo de radiação numa unidade industrial (Gamma-Pak Sterilizasyon) da Turquia, onde foram aplicadas as doses de 0,50 e 3,0 kGy. Em paralelo, algumas propriedades físicas das castanhas Portuguesas e Turcas foram avaliadas, designadamente: I) Dimensões axiais, correspondentes ao comprimento, largura e espessura; II) Diâmetro médio aritmético; III) Diâmetro médio geométrico; e IV) Esfericidade. Ao avaliar a cor de castanhas Portuguesas, Castanea sativa, com casca exterior sujeitas a várias doses de radiação gama, verificou-se que os parâmetros L (29,4+1,6 a 32,6+1,6), a (13,4+3,2 a 16,7+2,5) e b (8,4+2,4 a 13,4+2,4) não apresentaram qualquer relação com a dose aplicada e tempo de armazenamento. Em termos do interior do fruto, foram já observadas algumas diferenças. Em relação ao parâmetro L (82,1+2,6 a 87,2+0,5), este diminuiu ligeiramente após 30 dias de armazenamento, tendo sido esse decréscimo maior para as doses maiores (> 0,5 kGy). O parâmetro b variou pouco ao longo do tempo de armazenamento e com a dose, tendo sido, contudo, obtido o maior valor para a dose de 3,0 kGy e tempo de armazenamento de 30 dias (27,3+4,3). No entanto, este valor foi semelhante ao medido para a dose 0,25 kGy e igual tempo de armazenamento (27,2+4,9), o que sugere que doses maiores de radiação gama (até 3,0 kGy) parecem não provocar um maior amarelecimento do interior dos frutos. Em termos do parâmetro a, este pouco variou com a dose e tempo de armazenamento. Ao comparar as dimensões das castanhas Portuguesas e Turcas entre si, constatou-se que, em termos médios, a castanha Portuguesa apresentou um comprimento e esfericidade maiores em relação à castanha Turca. Pelo contrário, esta apresentou uma largura e espessura maiores, o que se traduziu em maiores diâmetros médios aritmético e geométrico. Em relação à cor da castanha Turca com casca, submetida aos vários ensaios - controlo e a diferentes doses da radiação gama -, constatou-se que os valores do parâmetro L medidos (29,3+2,20 a 33,0+2,07) foram semelhantes aos anteriormente referidos para a castanha Portuguesa, indicando que as duas castanhas são semelhantes em termos de brilho. Também para a castanha Turca não se observou qualquer relação entre este parâmetro e a dose aplicada ou tempo de armazenamento. Pelo contrário, no parâmetro a detectaram-se já algumas diferenças entre as duas castanhas. De facto, a castanha Turca apresentou menores valores, 9,3+2,6 a 11,9+1,6, quando comparada com a Portuguesa. Contudo, também para a castanha Turca não se observou qualquer relação entre este parâmetro e a dose ou tempo de armazenamento. Considerando os valores médios do parâmetro b para a castanha Turca, 6,8+2,8 a 12,2+2,8, verificou-se que esta apresentou sempre valores inferiores quando comparada com a Portuguesa, com excepção do valor obtido com a dose de 0,50 kGy no início do armazenamento (0 dias). Para ambas as castanhas verificou-se um ligeiro aumento do parâmetro b ao longo do tempo de armazenamento, tanto para o controlo como para as amostras sujeitas à dose 0,50 kGy. Contudo, para a radiação de 3,0 kGy, os valores obtidos foram semelhantes ao longo do tempo para ambas as castanhas. Em relação ao interior da castanha Turca, os valores para o parâmetro L (83,4+5,3 a 86,0+1,9) foram semelhantes aos determinados para a castanha Portuguesa, apresentando uma menor variação. Também não se detectaram diferenças entre doses aplicadas e tempo de armazenamento. Comportamento idêntico foi também observado para o parâmetro a. Ao contrário do observado com a castanha Portuguesa, com a castanha Turca observou-se um aumento no valor médio do parâmetro b ao longo do tempo de armazenamento: controlo 19,7+2,5 a 26,0+3,8 (0 e 30 dias), Dose = 0,50 kGy 20,5+3,2 a 26,0+6,1 (0 e 30 dias), Dose = 3,0 kGy 20,9+2,5 a 25,0+3,7 (0 e 30 dias). Ao comparar os valores obtidos no ensaio controlo e nos referentes às doses de 0,50 e 3,0 kGy no início e após 30 dias de armazenamento, os valores são semelhantes, indicando novamente que doses maiores de radiação gama (até 3,0 kGy) parecem não provocar um maior amarelecimento no interior dos frutos.Agroaguiar Lda. pela disponibilização das amostras; ON.2-QREN Project nº 13198/2010; A. L. Antonio agradece à Fundação para a Ciência e Tecnologia pela bolsa SFRH/PROTEC/67398/2010

The Fueling and Evolution of AGN: Internal and External Triggers

In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte

COVAD survey 2 long-term outcomes: unmet need and protocol

Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups