225 research outputs found

    An Adaptive Algorithm for Multipath Mitigation in GNSS Positioning with Android Smartphones

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    We present a solution for improving the robustness of GNSS positioning with Android devices. The proposed method combines an acquisition phase performed in a dedicated Android app (thus working on the edge) and a processing phase, based on a modified version of the open source library RTKLIB, performed on a dedicated server. The processing phase applies an improved version of the RTK library based on an adaptive algorithm for mitigating the multipath effect on satellite radio signals received by smartphone’s antennas. The algorithm is built on top of an extended version of the sigma-epsilon model in which weights associated to observables potentially affected by multipath errors are computed using logged data. In the paper, we will focus our attention on the architecture of the proposed solution and discuss preliminary experimental results obtained with the resulting system

    Stability Analysis of Open-Loop V/Hz Controlled Asynchronous Machines and Two Novel Mitigation Strategies for Oscillations Suppression

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    Asynchronous machines are always widely used in most industrial applications due to their reliability, flexibility, and manoeuvrability. To achieve variable speed operations, the quite simple open-loop V/Hz control is largely utilized. Under open-loop V/Hz control, the nonlinear interaction is well known to cause current and torque oscillations while operating at low to medium speeds under light loads. This article presents the stability analysis of induction motors at low\u2013medium frequencies under no-load conditions with the V/Hz control. A system representation in the form of state space is discussed, and the region of instability is plotted against the V/f plane. Two novel and refined methods for the mitigation of oscillations in the region of instability are presented. The two proposed algorithms are finally tested and validated through simulation on an inverter-fed induction motor drive system

    Reproductive performance in three Slovenian sheep breeds with different alleles for the MTNR1A gene

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    The aim of the research was to describe the polymorphisms of the MTNR1A gene in three Slovenian sheep breeds, and determine whether these polymorphisms affect reproductive performance. A total of 100 Bovška, 110 Istrian Pramenka, and 108 Jezersko-Solčavska ewes, were used. The rams were placed with the ewes on 10 October (Bovška), and 20 September (Istrian Pramenka). At each farm, the lambing date and number of newborn lambs were recorded to evaluate the fertility rate, number of days from ram placement with ewes to lambing (DRIL), and litter size. The Jezersko-Solčavska rams were maintained with the ewes of the flock throughout the year and data related to lambing during the entire year were recorded. The DNA sequences indicated there were eight nucleotide variations and that in the position g.17355358 was always associated with that in the position g.17355452. For the Bovška breed, there was an association between the G/G genotype in the position g.17355452, and relatively greater fertility (P < 0.05) and a shorter DIRL (P < 0.05). For the Istrian Pramenka breed, the T/T genotype in the position g.17355458 was positively associated with a greater fertility (P < 0.05) and shorter DRIL (P < 0.05). For the Jezersko-Solčavska breed, ewes with the G/G genotype in the position g.17355452 lambed more when there was a decreasing photoperiod whereas the ewes with the A/A genotype lambed more (P < 0.05) during the period when there were increasing photoperiods. The different polymorphisms studied were associated with reproductive performance in the three Slovenian breeds

    MTNR1A gene polymorphisms and reproductive recovery after seasonal anoestrus in different Mediterranean sheep breeds

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    The aims of this study were 1) to investigate the effect of MTNR1A gene polymorphisms on reproductive performance in ewes of one Italian and two Slovenian dairy sheep breeds (Sarda, Istrian Premenka and Boska, respectively) which were located at different latitudes, and 2) to highlight if the different season of the male placement with females that was utilized in the different breeding systems in Sardinia (Italy) and Slovenia resulted in different effects of these polymorphisms on reproductive functions. Reproductively mature ewes (n = 100) from each breed were utilized to conduct the study. To evaluate the reproductive efficiency, lambing dates and number of lambs born were recorded per ewe; additionally, the duration in days from ram placement with ewes to lambing (DRPEL), litter size and the fertility rate were determined based on lambing dates. In each breed, there were eight nucleotide variations within the MTNR1A gene exon II, two of which (g.17355358 and g.17355171), respectively, resulted in a valine to isoleucine, and alanine to aspartic acid substitution, in amino acid sequence. The SNPs at position g.17355452 and g.17355458 were determined to have effects on reproductive performance. Genotypes C/C and C/T at g.17355452 in Bovska and Sarda and genotype A/A at g.17355458 in Istrian Pramenka were associated with a greater fertility and a lesser duration in days from ram placement with ewes to lambing. These findings confirmed that the nucleotide sequences of the MTNR1A gene could affect reproductive functions of Mediterranean sheep

    Melatonin treatment in rams and their replacement with novel treated rams advance first lambing and increase fertility in sarda ewe lambs

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    This study aims to find reliable strategies for advancing first mating and shortening the period from weaning to first lambing in ewe lambs. Sarda ewe lambs (n = 400) were selected from two farms and allocated into four separated groups of 100, all of which were exposed to fertile, adult rams over the course of a 50‐day breeding period. The first treatment group (RMR) was exposed to four melatonin‐treated rams which were replaced every ten days, whilst the second treatment group (RM) was exposed to four melatonin‐treated rams which were not replaced. Alternatively, the first control group (RCR) was exposed to four untreated rams which were replaced every ten days, whilst the second control group (RC) was exposed to four untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The highest fertility rate was recorded in the RMR group (p ≤ 0.05). Shorter DRIL (p ≤ 0.01) and higher lambing concentrations were recorded in the RM and RMR groups as compared to the controls. The findings indicate that melatonin treatment of rams and their replacement at 10‐day intervals results in earlier onset of first mating, increased fertility rate in ewe lambs, and a higher number of ewes that lambs in a shorter time frame

    Energy metabolism and ketogenic diets: What about the skeletal health? a narrative review and a prospective vision for planning clinical trials on this issue

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    The existence of a common mesenchymal cell progenitor shared by bone, skeletal muscle, and adipocytes cell progenitors, makes the role of the skeleton in energy metabolism no longer surprising. Thus, bone fragility could also be seen as a consequence of a “poor” quality in nutrition. Ketogenic diet was originally proven to be effective in epilepsy, and long-term follow-up studies on epileptic children undergoing a ketogenic diet reported an increased incidence of bone fractures and decreased bone mineral density. However, the causes of such negative impacts on bone health have to be better defined. In these subjects, the concomitant use of antiepileptic drugs and the reduced mobilization may partly explain the negative effects on bone health, but little is known about the effects of diet itself, and/or generic alterations in vitamin D and/or impaired growth factor production. Despite these remarks, clinical studies were adequately designed to investigate bone health are scarce and bone health related aspects are not included among the various metabolic pathologies positively influenced by ketogenic diets. Here, we provide not only a narrative review on this issue, but also practical advice to design and implement clinical studies on ketogenic nutritional regimens and bone health outcomes. Perspectives on ketogenic regimens, microbiota, microRNAs, and bone health are also included

    The effects of vegetarian diets on bone health: a literature review

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    In these recent years many people are adopting a vegetarian type diet due to the numerous positive health effects of this regimen such as the reduction of the incidence of many chronic disorders like diabetes, hypertension, obesity and cancer. However this diet is quite restrictive and so it could be possible to have a deficiency in some specific nutrients, increasing the risk of osteoporosis and fractures. Although there are conflicting results on the effects of the vegetarian diet on bone health and fracture incidence, it is always recommendable in vegetarian people to have an adequate intake of calcium and vitamin D, through an increased intake of supplements, natural and fortified foods, an adequate intake of protein, fruit, vegetables, as well as vitamin B12. The aim of this literature review is to revise the actual knowledge of the effect of some nutrients and vegetarian diets on bone health. Copyright © 2022 Falchetti, Cavati, Valenti, Mingiano, Cosso, Gennari, Chiodini and Merlotti

    Detection of polymorphisms in the mtnr1a gene and their association with reproductive performance in awassi ewes

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    The economy in Mediterranean areas is tightly linked to the evolution of the sheep-farming system; therefore, improvement in ewe’s reproductive performance is essential in the developing countries of this area. MTNR1A is the gene coding for Melatonin receptor 1 (MT1), and it is considered to be involved in the reproductive activity in sheep. The aims of this study were: (1) identifying the polymorphisms from the entire MTNR1A coding region and promoter in Lebanese Awassi sheep flocks, and (2) investigating the association between the found polymorphisms and the reproductive performance, assessed as lambing rate, litter size, and days to lambing (DTL). The study was conducted in two districts of Lebanon, where 165 lactating ewes, aged 5.2 ± 1.5 years, with body condition score (BCS) 3.3 ± 0.4, were chosen and exposed to adult and fertile rams. From 150 to 220 days after ram introduction, lambing dates and litter sizes were registered. This study provided the entire coding region of the MTNR1A receptor gene in the Awassi sheep breed. Thirty-one single nucleotide polymorphisms (SNPs) were detected, five of which were missense mutations. The H2, H3, and H4 haplotypes were associated with lower DTL (p < 0.05), as well as the SNPs rs430181568 and rs40738822721, named from now on SNP20 and SNP21, respectively. These SNPs were totally linked and can be considered as a single marker. The ewes carrying the C allele at both these polymorphic sites advanced their reproductive recovery (p < 0.05). These results are essential for improving reproductive management and obtaining advanced lambing in Awassi ewes

    New polymorphisms at MTNR1A gene and their association with reproductive resumption in sarda breed sheep

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    The aim of this study was to characterize the MTNR1A locus in Sarda sheep breed, in order to identify potential single nucleotide polymorphisms (SNPs) associated with reproductive resumption. The reproductive performance of 200 lactating ewes, aged 3–5 years, with body condition score (BCS) 2.5–4.0, at least at their third lambing were monitored for two consecutive years. In both year the enrolled ewes were exposed for 100 days to 10 adult, fertile rams. Mating, pregnancy and lambing for each ewe were recorded in order to evaluate differences in reproductive performance according to the analysed genotypes. From individual blood samples, DNA was extracted to amplify and to sequence promotor, the coding region, a part of intron and of 3′ Untranslated region (3′ UTR) of the MTNR1A gene. A total number of 29 SNPs were found (named SNP1 to SNP29), five of which caused also amino acid changes. The polymorphic sites found at positions g.17355452C > T (SNP16, rs430181568) and g.17355358C > T (SNP17, rs407388227) were linked (D’ = 1 and r2 = 1) and showed a significant association to DRIL trait (distance in days from ram introduction to lambing). In both years, the ewes carrying C/C genotype in both these polymorphic sites showed the lowest DRIL compared to the other genotypes (P < 0.05). The ewes carrying C/C and T/C genotype exhibited the lambing peak at 170 days, and approximately 60% of the total lambing at 180 days from the ram introduction. Instead, ewes carrying T/T genotype showed the lambing peak around 200 days after ram introduction. Six haplotypes have been identified and the most frequent haplotype was also associated with lower DRIL (P < 0.05). Litter size displayed no statistical significance either among genotypes or among haplotypes. This study provided the major part of the MTNR1A gene in Sarda sheep breed and evidenced that SNP17 is associated with a shorter DRIL. The obtained results underlined the role of this polymorphism in improving reproductive efficiency in Sarda sheep and provides a suitable information for improving genetic selection

    Effect of body condition score, treatment period and month of the previous lambing on the reproductive resumption of melatonin-treated sarda breed sheep during spring

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    Stakeholders place great emphasis upon rationalizing the management and rearing techniques which are utilized within sheep farms. The present study aimed to investigate factors which may improve the reproductive performance of melatonin-treated Sardinian sheep via a series of three trials. The first trial (n = 100) investigated the effect of melatonin treatment alongside body condition score (BCS), the second trial (n = 150) investigated the effect of treatment alongside the date of treatment (treatment period) and the third trial (n = 150) investigated the effect of treatment alongside the previous lambing of the ewes. The findings indicated that melatonin is an effective tool for anticipating and improving the reproductive activity of in Sarda breed sheep during the springtime. Furthermore, to obtain optional results, melatonin implantation should be conducted in April, in ewes that have a BCS of >2.5 and that have passed their third month of lactation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
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