186,326 research outputs found
OBSERVATIONAL CONSTRAINTS OF THE INTERACTION BETWEEN PLANETS AND PROTOPLANETARY DISKS
No full textOver the course of almost three decades, exoplanet research has unveiled thousands of planets orbiting stars beyond our Sun. Surprisingly, the majority of these exoplanetary systems exhibit significant differences from our own Solar System. To comprehend the reasons behind these distinctions, it is imperative to study how planets form. Planets take shape during the star formation process, emerging from the material within the protoplanetary disk surrounding the young protostar. Interactions between these newly formed planets and the disk create observable effects on the disk itself, which can be detected in the sub-millimeter to centimeter wavelength range through advanced interferometers like ALMA and VLA.
In this Thesis, I explore various protoplanetary disks, each possessing unique characteristics. They range from extended disks with noticeable substructures in dust emission to a disk surrounding a very low-mass star that may have undergone giant planet formation, as well as a compact, structureless disk exhibiting a peculiar behavior whose origin remains uncertain. The methodologies employed in these investigations are diverse, encompassing high-resolution ALMA observations, comprehensive numerical modeling involving hydrodynamical and radiative transfer simulations, and a multiwavelength analysis spanning from centimeter to sub-millimeter wavelengths, incorporating data from VLA, ALMA, and other interferometers. In all the systems under examination, the presence of planets could potentially play a role, whether giant planets shaping observed dust substructures at tens or hundreds of astronomical units or inner planets generating unresolved substructures, preventing radial drift and leading to the formation of a compact disk
PHYSIOLOGICAL APPROACH TO THE STUDY OF AUTOCHTHONOUS CATTLE BREEDS OF NORTHERN ITALY
No full textThis PhD project is focused on the physiological characterization of some autochthonous bovine breeds of Northern Italy, using many biological parameters in order to make a comparison with the cosmopolitan breeds. Despite the lower milk production, these breeds present other interesting and peculiar features, such as rusticity, frugality, good food conversion, high product quality (milk and meat), good fertility and good resistance and resilience against the diseases. We applied a multidisciplinary approach to study the physiological bases of the interesting traits present in the local breeds, studying three main issues: the metabolism of the transition period, the milk composition and technological properties and the ethological traits.
a) Biodiversity of the transition period
i) Study of the milk ketone bodies assessment in Modenese breed and Holstein with a characterization of physiological, reproductive and productive performances.
The objective of this study was to characterize some productive, reproductive and metabolic parameters (ketone bodies) in the Italian autochthonous cattle breed Modenese, comparing them with those of Holstein and their crossbred (F1=Modenese x Holstein; F2=Modenese x F1) breed in the same farm, in order to understand if there is a different metabolic picture that can influence the reproductive performances. Milk samples have been collected at different times of lactation (20, 40, and 90 days in milk (DIM)) and analyzed by gas chromatography-mass spectrometry to obtain the the concentration of ketone bodies. In all time points, the Modenese breed showed a significant (p<0,05) lower concentration of ketone bodies. The F1, F2 and Modenese showed also better reproductive performances when compared to Holstein, with a significant lower (p<0,05) length of days open period.
ii) Comparative evaluation of the transition period: Italian autochthonous breed vs. Holstein
We evaluated the metabolic indicators, milk protein profiles and the milk microbiota in 6 Holstein Friesian and 4 Rendena cows reared on the same farm and under the same management conditions. Quarter milk samples and blood were collected from all cows at dry-off (T1), 1 day after calving (T2), 7-10 days after calving (T3) and 30 days after calving (T4). Blood samples were used for the analysis of plasma metabolites such as: glucose, total cholesterol, urea, inorganic phosphorus, total protein, albumin, total bilirubin, aspartate aminotransferase (GOT), γ-glutamyltransferase (GGT), creatinine, NEFA, β-OH-butyric acid (BHBA), thiol groups (SHp) and ferric reducing antioxidant power (FRAP). Quarter milk samples were subjected to bacteriological culture, protein profiles and characterization of the milk microbiota. Holstein cows showed a more severe fat mobilization, lower muscle mobilizationand systemic inflammatory response at T2 and T3 in comparison with Rendena cows. Significant differences were seen in the general composition of the milk microbiota of the two breeds. Concerning the milk protein abundance profile, pronounced differences were seen in the colostrum (T2), with significantly higher amounts of protective molecules (immunoglobulins and other immune-related proteins) in Rendena.
b) “Milks” biodiversity
i. Fatty acid profile, desaturase and atherogenic indices in milk of Holstein Friesian and Italian autochthonous cattle breeds
In this study the characteristics of the fatty acid profile in local Italian bovine breeds (Cabannina, Varzese, and Valdostana) are compared with those of Friesian, , a conventional breed, during the first period of lactation. The local breeds show a general trend to have higher unsaturated fatty acid percentages, as well as lower desaturase indices (related to C14, C16 and C18) and atherogenic index, with respect to Friesian cows.
ii. NMR-based metabolomics as a tool to characterize the milk biodiversity
In the present study we investigated the variations of the metabolic profiles during lactation in milks obtained from Friesian and autochthonous breeds from Northern Italy by 1H-NMR metabolomics. Furthermore, the external factors influencing the milk composition were minimized: the cows were bred on the same farm, were fed with the same diet, and were matched by for the lactation interval and lactation stage. Our results showed a difference in milk composition between breeds and in relation to stage of lactation.
iii. Milk microbiome characterization between healthy Holstein Friesian and Rendena cows
The aim of this study was to compare the milk microbiota in 6 Holstein and 3 Rendena cows reared on the same farm under the same management conditions, with a special focus on the transition period. Four time points (dry-off, 1 day after calving, 7-10 days after calving and 30 days after calving) were considered. The taxonomic profiles of cosmopolitan and local breeds were dominated by Firmicutes, mostly represented by the Streptococcus genus, followed by Proteobacteria, Bacteriodetes, and Actinobacteria. In both Rendena and Holstein the most abundant species was represented by Str. thermophilus, a lactic acid bacterium widely used in the fermentation of dairy products. However, the microbial populations were profoundly different in the two breeds along all the time points: the Rendena milk samples showed lower biodiversity and more stable microbial ecosystem.
c) Ethological biodiversity
i. Cattle Personality biodiversity in autochthonous Italian breeds: a pilot survey
This study assessed personality in five different cattle breeds (Bos taurus), two cosmopolitan (Holstein and Brown) and three Italian autochthonous, through a personality questionnaire completed by handlers (milkers). The objective was to determine whether this method could detect differences in personality, including breed, age and sex differences. Milkers’ assessments found breed and individual differences in the animals studied. Differences in personality traits resulted to be quite evident between individuals but consistent within each breed.
With these results, we have shed some light on the physiological mechanism at the base of the interesting features showed by the autochthonous Italian cattle breeds. This can contribute to the re-evaluation of bovine local breeds and their products, in order to recover the continuously reducing numbers, and enhance the quality of derived products, with positive effects on farm economy and biodiversity
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Role of PTX3 in the immune response to S. Aureus intra-mammary infection
No full textMastitis is an inflammation of the mammary gland commonly caused by bacterial infection. Regardless of the extensive management practices, it represents one of the most economically important health traits for milk production.
Pentraxins are a superfamily of conserved molecules with immune functions such as complement activation and opsonization. PTX3 is the prototypic long pentraxin and is produced by different cell populations after pro-inflammatory stimuli (TLR ligands, IL-1β, TNFα). Some studies have demonstrated the up-regulation of PTX3 mRNA during ruminant mastitis, but its role is still unknown (ref). To better understand the role of PTX3 we investigated its pattern of expression in a model of S. aureus intra-mammary infection in goat.
Because no data on goat PTX3 are available, we first studied PTX3 pattern of expression in a wide panel of goat healthy tissues. PTX3 mRNA was expressed at high level in bone marrow, mammary gland, aorta, pancreas, skin and lungs. Than we focus our attention to the mammary gland; six healthy goats were infused with PBS in the right udder and with S. aureus in the left udder and mammary biopsies for immunohistochemistry and RNA extraction were collected 30 h post infection. Immunohistochemistry reveled that in non infected udders PTX3 was mainly expressed in the apical cytoplasmic portion of mammary epithelial cells (MEC) and in macrophages; wheras during S. aureus infection PTX3 was up-regulated in MEC and in the secretum. Moreover, PMNs recruited during infection were variably intensely positive. PTX3 mRNA expression was low in healthy udders compared to the infected ones, indeed this molecule is commonly induced after pro-inflammatory stimulation.
Finally, we investigated the modulation of PTX3 during field mammary infection, comparing its expression in healthy and S. aureus infected goats (blood leukocytes, milk somatic cells, milk fat globules). PTX3 mRNA was significantly up-regulated in circulating PMN and milk somatic cells. In circulating monocytes and in milk fat globules we observed a statistically non significant tendency of increase expression in S. aureus infected animals.
These observations could reveal a role of PTX3 as a key player in the immune response of mammary gland to S. aureus infection and it could represent a marker of mastitis in goat, that can be used for a fast and early diagnosis of intra-mammary infection in the field
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Heat treatment of bovine colostrum : I. Effects on bacterial and somatic cell counts, immunoglobulin, insulin, and IGF-I concentrations, as well as the colostrum proteome
No full textThe objective of this study was to investigate the effects of heat treatment on colostral low-abundant proteins, IgG and IgA, insulin, and insulin-like growth factor I (IGF-I), as well as bacteria and somatic cells. First-milking colostrum samples >8 L and Brix % > 22.0 were harvested from 11 Holstein cows on a commercial dairy in New York State and split into 2 aliquots using single-use colostrum bags. One aliquot of each pair was cooled on ice immediately after harvest (raw, R; n = 11), and the other was heat-treated for 60 min at 60°C (heat, H; n = 11). All samples were analyzed for IgG and IgA via radial immunodiffusion assay and insulin and IGF-I concentrations by radioimmunoassay. Total bacterial counts and somatic cell counts (SCC) were determined using standard plate culture techniques and flow cytometry, respectively. Samples from a subset of 5 pairs (n = 10) were further analyzed by nano liquid chromatography-tandem mass spectroscopy, after ultracentrifugation at 100,000 × g for 60 min at 4°C to enrich the low-abundant protein whey fraction. Data were analyzed using either paired t-test or Wilcoxon signed-rank test or using an online software package to analyze proteomics data. Outcomes of proteomics analysis were fold change ≥1.5 between pairs, and paired t-tests with false discovery rate–adjusted P-value < 0.05. The median reduction of IgA concentrations was 8.5% (range: 0–38.0%) due to heat treatment, whereas IgG concentrations did not change due to treatment. Insulin concentrations decreased by a median of 22% (7–45%), and IGF-I decreased by 10% (0–18%) in H samples. Heat treatment was associated with a median reduction of SCC of 36% (0–90%) in paired samples, as well as a median reduction in total bacterial count of 93% (45–100%) in H versus R samples. Proteomics analysis identified a total of 328 unique proteins that were present in all 10 samples. Nine of the 25 proteins that decreased by at least 1.5-fold in H compared with R were identified as complement proteins. We conclude that heat treatment of colostrum is associated with a reduction in the concentration of bacterial counts and SCC, IgA, insulin, and IGF-I. In addition, proteomics analysis of colostral whey identified several complement components and other proteins that decreased in abundance due to heat treatment. Although IgG concentrations were unaffected and a reduction in bacterial counts was achieved, the change in several immunologically active proteins and growth factors may have biologically important effects on the developing immune system of the neonate fed heat-treated colostrum
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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