863 research outputs found
Evolution of physicochemical, morphological and aromatic characteristics of Italian PDO dry-cured hams during processing
The aim of this work was to follow the evolution of physicochemical (dry matter, NaCl concentration, pH, water activity), morphological (image analysis) and aromatic (e-nose) characteristics of the three main Italian PDOs during processing, from slaughtering to end of ripening. Main phenomena distinguishing the PDOs are NaCl concentration increase, which is higher in Toscano than in Parma and San Daniele hams, starting from the salting phase. Water activity values decrease during processing, and the lowest values are detected in Toscano ham. Changes in morphological parameters (area, shape) and in color progressively occur during processing and are more pronounced in Toscano ham. A clear evolution of aroma of the three PDOs has been observed by e-nose, and the complexity of the aromatic profile of the ripened hams is clearly highlighted
Heat transfer delay method for the fluid velocity evaluation in a multi-turn pulsating heat pipe
A multi-turn closed loop pulsating heat pipe made of aluminium is tested in vertical bottom heated mode and
different condenser temperatures with the aim of providing quantitative information regarding its flow dynamics
through a novel post-processing technique on the local wall-to-fluid heat flux, evaluated within the adiabatic
section. The studied device is made of an annealed aluminium tube (inner/outer diameter: 3/5 mm), folded in 14
turns and partially filled with methanol (volumetric filling ratio: 50%). The aluminium channels are coated with
a high-emissivity opaque paint, thus allowing thermographic measurements on the outer wall by means of a
high-resolution medium wave infrared camera. The proposed method, named Heat Transfer Delay Method, is
validated by means of a dedicated experimental approach. Then, the acquired time-space temperature maps are
used as input data for the inverse heat conduction problem resolution approach to estimate the local convective
heat flux locally exchanged at the inner wall-fluid interface. The resulting wall-to-fluid heat fluxes are then post-
processed by applying the Heat Transfer Delay Method to the oscillatory and circulatory flow modes. The average
fluid velocity is assessed at varying working conditions during the circulatory flow, finding values up to 0.77 m/s
and 0.3 m/s for condenser temperature equal to 20 â—¦C and 10 â—¦ C, respectivel
Determinants of obesity in Italian adults : the role of taste sensitivity, food liking, and food neophobia
Recent evidence has suggested that factors related to sensory perception may explain excess weight. The objective of this study was to consider multiple aspects while investigating the phenomenon of obesity. One goal was to compare taste acuity (taste threshold and density of fungiform papillae) in both normal weight and obese subjects. Thresholds for 4 basic tastes and the fat stimulus were investigated. A second research goal was to study the relationship between food neophobia and food liking according to the body mass index and taste sensitivity. The results showed that obese subjects seem to have higher threshold values and a reduced number of fungiform papillae than do normal weight subjects. Food neophobia did not vary with nutritional status, whereas differences were found for food liking, with obese subjects showing significantly higher liking ratings for high energy dense products compared with normal weight subjects
Meiotic behavior of a nonaploid accession endorses x = 6 for Brachiaria humidicola (Poaceae).
Brachiaria humidicola (Poaceae), originally from Africa, is an economically important pasture plant in tropical South America. An accession of B. humidicola (H038) collected from the wild African savanna (Mbeya, Tanzania) showed irregular microsporogenesis. This meiotic behavior was consistent with an allopolyploid origin. Multivalent chromosome association at diakinesis gave tri- to octavalents, associated with two nucleoli in some cells. Six non-congregated univalents in metaphase I and anaphase I, along with previous lines of evidence for x = 6 in B. humidicola, confirm H038 as a nonaploid accession, 2n = 9x = 54. Asynchrony in the genome during microsporogenesis also corroborated this assumption. Its putative origin could be a cross between two related species with different rhythms in meiosis. The meiotic behavior of this accession reinforces the hypothesis of the existence of a new basic chromosome number (x = 6) for Brachiaria. The use of this accession in the breeding of this important forage grass for the tropics is discussed
Impact of ambient odors on food intake, saliva production and appetite ratings
The aim of this study was to investigate the effect of ambient odor exposure on appetite, salivation and food intake. 32 normal-weight young women (age: 21.4\ua0\ub1\ua05.3\ua0year; BMI: 21.7\ua0\ub1\ua01.9\ua0kg/m2) attended five test sessions in a non-satiated state. Each participant was exposed to ambient odors (chocolate, beef, melon and cucumber), in a detectable but mild concentration, and to a control condition (no-odor exposure). During each condition, at different time points, participants rated appetite for 15 food products, and saliva was collected. After approximately 30\ua0min, ad libitum intake was measured providing a food (chocolate rice, high-energy dense product) that was congruent with one of the odors they were exposed to. A significant odor effect on food intake (p\ua0=\ua00.034) and salivation (p\ua0=\ua00.017) was found. Exposure to odors signaling high-energy dense products increased food intake (243.97\ua0\ub1\ua022.84\ua0g) compared to control condition (206.94\ua0\ub1\ua024.93\ua0g; p\ua0=\ua00.03). Consistently, salivation was increased significantly during chocolate and beef exposure (mean: 0.494\ua0\ub1\ua00.050\ua0g) compared to control condition (0.417\ua0\ub1\ua00.05\ua0g; p\ua0=\ua00.006). Even though odor exposure did not induce specific appetite for congruent products (p\ua0=\ua00.634), appetite scores were significantly higher during odor exposure (p\ua0<\ua00.0001) compared to the no-odor control condition and increased significantly over time (p\ua0=\ua00.010). Exposure to food odors seems to drive behavioral and physiological responses involved in eating behavior, specifically for odors and foods that are high in energy density. This could have implications for steering food intake and ultimately influencing the nutritional status of people
Recurrence of multiple meiotic abnormalities in maize genotypes from the same origin and their influence on productivity.
The frequency of meiotic abnormalities among single-, double- and three-way cross experimental hybrids and their parental inbred lines is studied. Among the sixteen inbred lines examined, fifteen originated from populations developed at the National Center of Research in Maize and Sorghum (CNPMS/Embrapa) and one from a population developed at ESALQ (Faculty of Agriculture Luiz de Queiroz of the University of SĂŁo Paulo). Previous analyses of homozygous and heterozygous maize genotypes from CNPMS populations demonstrated high meiotic instability. The present investigation aims at analyzing the meiotic behavior of different inbred lines obtained from CNPMS populations by another breeding enterprise to verify the presence of the same abnormalities and determine whether the abnormalities might compromise productivity. Analyses showed the presence of some abnormalities described previously, albeit at a lower frequency. The most common abnormalities in homozygous and heterozygous genotypes from CNPMS populations were related to irregular chromosome segregation and to chromosome stickiness. An inbred line from the ESALQ population showed only abnormalities related to irregular chromosome segregation caused by the presence of univalent chromosomes. The Pearson correlation procedure indicated high negative correlation between meiotic abnormalities and productivity
Genome elimination during microsporogenesis in two pentaploid accessions of Brachiaria decumbens (Poaceae)
Polyploidy is a prominent and significant force in plant evolution, taking place since ancient times and continuing until today. Recent cytogenetic studies in the genus Brachiaria using germplasm collected from wild African savannas in the 1980s revealed that most species and accessions within species are polyploid. Diploid, tetraploid, and pentaploid accessions have been found. We found asynchronous meiosis during microsporogenesis, followed by genome elimination, in two pentaploid (2n = 5x = 45) accessions (D53 and D71) of a hardy, invasive pasture grass, introduced from Africa to Brazil, Brachiaria decumbens. In these accessions, chromosomes paired as 18 bivalents and nine univalents during diakinesis, suggesting that these accessions resulted from a recent event of natural hybridization. The lack of chromosome associations in the genomes suggests that these accessions resulted from hybridization between two genotypes that are not closely related, with low genome affinity and with different meiotic rhythms. This supposition is reinforced by the meiotic behavior of the nine univalents, which were always laggard in relation to the other chromosomes and eliminated as micronucleiin microspores. The behavior of these accessions, which have an odd level of ploidy and confirmed genome elimination, supports the general assumption that a polyploid accession can undergo a new event of polyploidization by natural hybridization (neopolyploidyzation). This evidence for natural hybridization in Brachiaria shows that this is a wild genus in an ongoing evolutionary process
A new and distinctive male-sterile, female-fertile desynaptic mutant in soybean (Glycine max).
A spontaneous desynaptic mutation, affecting only microsporogenesis and causing pollen sterility, has been detected in BR97-12986H, a line of the official Brazilian soybean breeding program. In this male-sterile, female-fertile mutant, up to metaphase II, the meiotic behavior was similar to that described for the st series of synaptic mutants previously reported in soybean. Besides many univalents, few or total absence of bivalents were recorded in diakinesis. Bivalents presented one or two terminal chiasmata, while univalents retained the sister chromatid cohesion. Bivalents and most univalents congregated at the equatorial metaphase plate, although univalents frequently migrated to the poles prematurely. Laggards resulting from delay in chiasmata terminalization were also recorded. Distinctly different in their behavior from st series soybean mutants, telophase I-originated micronuclei of different sizes organized their own spindle in the second division. This behavior contributed towards an increase in genome fractionation. Several microspores and microcytes of different sizes were recorded at the end of meiosis. Pollen sterility was estimated at 91.2 %. Segregation ratio for sterility in this line and its progenies reached 3:1. Allelism tests with st series of synaptic mutants are in progress. The importance of male-sterile, female-fertile mutations for soybean breeding programs is discussed
Stigma receptivity, mode of reproduction, and mating system in Mesosetum chaseae luces (Poaceae), a native grass of the Brazilian Pantanal.
Mesosetum chaseae Luces, known regionally as "grama-do-cerrado", is abundant in the Pantanal region in Brazil and contributes significantly to livestock and environmental conservation. This species is under basic studies at Embrapa Pantanal (Nhecolândia subregion, Pantanal, Corumbá, MS, Brazil). In this study, we present data about stigma receptivity, mode of reproduction, and mating system for 10 accessions collected in Nhecolândia subregion (Pantanal). Stigma receptivity was optimal, producing innumerous oxygen bubbles upon testing with hydrogen peroxidase. Clarified ovaries analyzed under interference microscopy showed an embryo sac of the Polygonum type, typical of sexual species. The mating system, tested in protected flowers, indicated allogamy. These data are important for subsidizing future breeding programs for this species
Uso de testes colorimétricos na determinação da viabilidade do grão de pólen de acessos da grama-do-cerrado, Pantanal.
A principal economia do Pantanal é a bovinocultura de corte, criada em sistemas extensivos, com uso dos recursos forrageiros nativos. No entanto, há carência de estudos básicos da reprodução indicativos do potencial de acessos para futuros programas de seleção e melhoramento. Nesse contexto, objetivou-se avaliar a viabilidade do pólen de 10 acessos, presentes do Banco Ativo de Germoplasma, implantado pela Embrapa Pantanal na fazenda Nhumirim, sub-região da Nhecolândia, Pantanal, Corumbá, MS
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