1,722,194 research outputs found
Genetic analysis of production, immunity and behaviour in laying hens
No full textThe new regulations about the husbandry of laying hens and the so-called genomic revolution offer both opportunities and challenges for the breeding of layers. Hens are currently housed mainly in battery cages of 4 individuals each. Following recent developments of the communitarian legislation, many countries will soon adopt furnished cages or non-cage systems, which will lead to larger groups of hens. Also, beak-trimming will be prohibited in EU countries in the near future. Advancements in sequencing technology are making an always greater number of genetic markers available at increasingly cheaper prices, making genome-wide studies possible and helping geneticists to start unraveling the mystery of the genetic make-up of animals, which until a few years ago was considered a black-box. This thesis touches upon the impact of such innovations on the breeding of laying hens. Use of pooled data in the genetic evaluation of laying hens Hens are usually housed in cages and therefore pooled instead of individual egg records are often available: a pooled egg record is the total production of a cage, when the egg production of the individual hens is unknown. Current selection schemes are carried out in nucleus herds where hens are housed individually, so that egg production of individual birds can be recorded and used for genetic evaluations. Based on this information sires and dams are selected. Such a selection scheme based on individually housed hens introduces a discrepancy between the environment where hens are selected and the environment in which hens are kept for commercial egg production (group housing). Selecting animals in one environment and using them in a different environment might lead to genotype x environment interaction (Besbes and Ducroq, 2003), thereby reducing the realized response to selection. Future husbandry conditions, with larger groups of hens or hens housed in furnished cages might make this problem even worse. A method to use pooled data in the genetic evaluation of laying hens would therefore be of interest. In Chapters 2 and 3 of this thesis it is described how to use pooled records for the estimation of heritability and breeding values. In chapter 2 the use of individual and pooled observations is compared. Individual body weights of hens at different ages were available: these were then pooled by cage in order to create pooled records. Heritabilities estimated from pooled and individual data correlated well: the standard error of estimates based on pooled records was however about twice that of estimates based on individual records. The accuracy of EBVs from pooled data is lower than the accuracy of EBVs from individual data; in the case of sires with at least 10 offspring the reduction in accuracy was about 23%. This loss of precision in estimating genetic parameters and breeding values is understandable considering that pooled records are a less detailed of information. However, this lower accuracy should be interpreted in the context of direct vs indirect selection. The breeding goal is the trait under commercial conditions (group housing), and if testing is under individual housing, the genetic correlation between group and individual housing is relevant. The ratio of the selection response for direct and indirect selection is a function of the accuracies for both situations, the standard deviations of the traits and the genetic correlation between the traits (Falconer, 1989). Similarly, the ratio between accuracies based on pooled and individual data provides a threshold for the genetic correlation between individual and group housing below which pooled data would result in a greater selection response. In practical breeding also the costs of individual housing relative to the costs of group housing are relevant. Since group housing is cheaper than individual housing, more selection candidates could be tested for the same level of costs. This would in turn result in higher selection intensity and larger response to selection. In chapter 3 the method of analyzing pooled data developed in chapter 2 was compared with an approximation consisting in assigning cage means to each hen in a cage, then treating them as individual observations. Cross-validation was used to compare the two methods: the method developed in Chapter 2 performed consistently better than the approximate method in terms of predicting ability. In the general discussion, finally, it was described how to estimate genetic and phenotypic correlations from pooled data. Across-line association studies for immune response and feather pecking behaviour The great number of genetic markers available at increasingly lower prices has been fostering developments in genomic research. Association studies between genetic markers and phenotypes are typically conducted within populations (breeds, or lines): the amount of LD conserved in a population is exploited using high marker density, such as SNP chips, and markers relatively close to QTLs are expected to show significant effects in association studies. In this thesis we propose to take it one step further and perform association studies across lines. This requires higher marker density but increases the resolution. The amount of LD conserved across lines is expected to be lower than within lines and the phase of the marker-phenotype association might be different in the different lines. On the other hand markers that happen to show significant effects in an across-line association study are likely to be close to the QTL. These issues in conducting marker-phenotype association studies across populations were addressed in Chapters 4 and 5 of this thesis, where it was shown how to deal with multiple populations when analyzing hens from 9 different genetic lines of White Leghorn and Rhode Island Red origin genotyped for a panel of 1536 SNP (Single Nucleotide Polymorphism) markers. The traits analysed were immunological parameters and plumage damage due to feather pecking behaviour, two classes of traits for which, given that they have relatively low heritability and are difficult and expensive to measure, genomic information may be particularly valuable. Immunological parameters might be used in selection programmes aimed at improving disease resistance of laying hens, while information on the genetic background of feather pecking behaviour can be useful in reducing problems due to this behavioural disorder of layers. Under future husbandry conditions susceptibility to infectious diseases and feather pecking are expected to become more serious problems: both aspects of layer production are in fact related to the number of individuals that interact with each other, which will increase as a result of the application of the EU directive 1999/74/EC. In addition, the ban of beak-trimming will make it more difficult to control the consequences of feather pecking (plumage damage, cannibalism, mortality). Genetic selection might represent an appealing addition to the current control measures. The association studies identified several regions of interest. The gene for interleukin 17 (IL17), on chromosome 3, was found to be associated with natural and acquired antibody titres, and with the classical and alternative pathways of complement activation. The major histocompatibility complex (MHC) genes on chromosome 16 showed significant association with natural and acquired antibody titres and classical complement activity. The interleukin 12B gene (IL12B) on chromosome 13 was associated with natural antibody titres. As for feather pecking behaviour, a role of the gene for the serotonin receptor 2C (HTR2C) on chromosome 4 was found. This supports existing evidence of a prominent involvement of the serotonergic system in the modulation of this behavioural disorder in laying hens. The genes for IL9, IL4, CCL4 and NFKB were found to be associated to plumage condition, revealing relationships between the immune system and behaviour. <br/
Non-Slender <i>n</i>-Link Chain Driven by Single-Joint and Multi-Joint Muscle Actuators: Closed-Form Dynamic Equations and Joint Reaction Forces
Full text linkThe author has derived the closed-form dynamic equations for a planar musculoskeletal chain composed of a generic number n of rigid links connected by ideal revolute joints. Single-joint and multi-joint muscles have been modeled as linear force actuators that can span from one joint to all the joints of the chain. The generic shape and size of each individual link of the chain accounts for different alignments among the center of mass of the link, the centers of rotation of the joints that articulate the link with its neighbors, and the points of application of the muscle forces and the possible contact external resistances acting on the link. The joint torque and the reaction force acting on each joint have been determined in closed-form by analytical quantification of the unique contribution of each individual kinematic and kinetic variable: (1) force of each single-joint or multi-joint muscle spanning or non-spanning the joint; (2) weight and contact external resistances acting on each individual link of the chain; (3) position, angular velocity, and angular acceleration of each individual link of the chain. The analytical results derived in this study can be applied to multilink musculoskeletal chains with deep/superficial and segmental/global muscles
Nazareno Biscarini (1835-1907)
No full textIl contributo presenta gli esiti delle ricerche svolte sulla figura di Nazareno Biscarini (1835-1907), architetto perugino formatosi presso la Scuola di Architettura dell’Accademia di Belle Arti di Perugia. Allievo di Giovanni Santini e collega di studi di Guglielmo Calderini, tra il 1884 e il 1898 diviene anch’egli professore della medesima Scuola. Partecipa a concorsi ed elabora progetti per aree ed edifici di rilievo del capoluogo umbro. Opera prevalentemente in ambito locale, nella città natale e nella relativa provincia. In particolare, realizza numerosi edifici sacri appartenenti alle cosiddette “chiese leonine”, edificate o ristrutturate in maniera diffusa nel territorio regionale per volere del vescovo Vincenzo Gioacchino Pecci. Progetta inoltre diversi monumenti e cappelle sepolcrali, ma anche altre importanti opere tra cui residenze nobiliari (villa-castello Gallenga-Stuart in località Mandoleto) e architetture civili (Teatro Concordia a Marsciano). La sua opera, allineata alla tendenza eclettica del periodo in cui si inserisce, si esprime mediante la riproposizione di canoni stilistici romanici, gotici e rinascimentali; l’apparato ornamentale attinge al repertorio di terrecotte architettoniche della fornace Angeletti-Biscarini, di cui è titolare il fratello Francesco
Innovative technologies for knee rehabilitation in subjects with anterior cruciate ligament injuries.
No full textIntroduction Recent theoretical studies indicate that during leg extension exercises
the tibiofemoral shear forces and the ACL strain-forces can be externally modulated.
These modulations can be obtained by a controlled displacement of the application
point of the resistance force along the lower-leg during the knee flexion/extension
(Biscarini, 2008), or through an external compressive force applied on the knee joint
(Fleming et al., 2007). Methods We have designed and developed two innovative
leg extension prototypes which integrate these functions. In the first prototype, the
resistance lever of a standard leg-extension equipment was replaced by a linear
guide along with the resistance pad can slide. The pad movement along the guide is
generated by an electric motor controlled by an angular encoder placed on the
rotation axis of the equipment, and a linear encoder installed along the linear guide.
A feedback control algorithm was developed to provide an accurate and fast
dynamic control of the pad positioning. In the second prototype, a foot platform
was inserted at the distal side of the resistance lever to exert a controlled axial
compression on the lower limb during the exercise. Two protocols for surface EMG
and imaging techniques measurement were designed to assess and compare the
levels of hamstring co-contraction (which is known to represent a protective factor
for the ACL) and the anterior tibial translation (which is proportional to the ACL
strain-force), during the exercise with these two new prototypes and the standard
equipment, at different levels of external resistances. Each trial was also repeated
encouraging the subjects to intentionally enhance hamstring co-activation during
the exercise. Results EMG data collected on seventeen healthy subjects indicate that
hamstring co-activation is not influenced by pad movement and axial compression.
However, the hamstring co-activation was increased from two to four times when
the subjects were encouraged to intentionally co-contract the knee flexor muscles
during the leg extension exercise. Discussion Intentional hamstring co-contraction in
leg extension exercises can be an effective strategy for ACL protection and
tibiofemoral joint stability in ACL deficient patients, and in rehabilitation programs
after cruciate ligament reconstruction. Further investigations with imaging
techniques will definitely asses the effectiveness of the two prototypes. References
Biscarini (2008). Medical Engineering & Physics 30(8), 1032-1041 Fleming et al.
(2003). Am J Sports Med 31(5), 701-70
Dynamics of Two-Link Musculoskeletal Chains during Fast Movements: Endpoint Force, Axial, and Shear Joint Reaction Forces
No full textThis study provides a dynamic model for a two-link musculoskeletal chain controlled by single-joint and two-joint muscles. The chain endpoint force, and the axial and shear components of the joint reaction forces, were expressed analytically as a function of the muscle forces or torques, the chain configuration, and the link angular velocities and accelerations. The model was applied to upper-limb ballistic push movements involving transverse plane shoulder flexion and elbow extension. The numerical simulation highlights that the shoulder flexion and elbow extension angular acceleration at the initial phase of the movement, and the elbow extension angular velocity and acceleration at the later phase of the movement, induce a proportional medial deviation in the endpoint force direction. The forearm angular velocity and acceleration selectively affect the value of the axial and shear components of the shoulder reaction force, depending on the chain configuration. The same goes for the upper arm and elbow. The combined contribution of the elbow extension angular velocity and acceleration may give rise to anterior shear force acting on the humerus and axial forearm traction force as high as 300 N. This information can help optimize the performance and estimate/control of the joint loads in ballistic sport activities and power-oriented resistance exercises
Lattice Boltzmann pollution dispersion in a shallow water body: the case of Trasimeno Lake
No full textThis work focuses on the application of the Lattice Boltzmann Method in natural water bodies (lakes, rivers, reservoirs) under the background of human activities and climate change. The mathematical model used is based on the two dimensional LB method (D2Q9), with shallow water formulation coupled with a water pollution dispersion routine. The LB method belongs to a new class of mesoscopic methods, based on a discretized formulation of the Boltzmann kinetic equation. The model is simple to implement, accurate andsuitabletosimulateshallowwaterbodies[Tubbs, 2012]. Moreover, thekineticapproachcorrectlysolves small scale phenomena [Biscarini, 2011] and multiphase flows and also provides an effortless treatment of source terms. The model is firstly validated through benchmark problems available in literature and then applied to simulate pollution dispersion in a lake. As a case study, we chose the Trasimeno Lake, which is located in Umbria Region and is the fourth biggest Italian lake, with an extension of about 121.5 km2 and an average depth of 4.3 m. The simulation of pollution dispersion takes into account the influence of seasonal level variations and of wind forces. The progressive disappearance of reed bed vegetation (Phragmites australis) near the lakeshore also affects boundary conditions in terms of lakeshores roughness and nutrients concentration, thus different scenarios are simulated. The topic appears remarkable in order to save the ecological balance of the Trasimeno Lake that is affected by the increased concentration of dissolved salts and pollutants during the dry period
Organic Bioelectronics for Regenerative Medicine
No full textElectronic transducers of neuronal cellular activity are important devices in neuroscience and neurology. Organic field-effect transistors (OFETs) offer tailored surface chemistry, mechanical flexibility, and high sensitivity to electrostatic potential changes at device interfaces. These properties make them attractive for interfacing electronics to neural cells and performing extracellular recordings and stimulation of neuronal network activity.
Here I want to present an emerging area of interest where the OFET is used as a gauge to supply a variety of electrical, chemical and electrochemical stimuli to neuronal cells, in an effort to stimulate their plasticity else to differentiate neuronal stem cells into neurons. I will overview the progresses of an ongoing EU project, “Implantable Organic Nanoelectronics” (I-ONE-FP7) which is aimed to the use of organic electronics in implantable devices for the treatment of the spinal cord injury (SCI). The project is presently at midterm, and I will highlight the advances to date and discuss the direction of further development towards in-vivo experiments on animal model of the SCI.
This work involves collaboration of several partners, that I would like to acknowledge through the principal investigators: S. Pluchino (Univ. of Cambridge), M. Berggren and D. Simon (Univ. Linkoeping), F. Zerbetto and S. Rapino (Univ. of Bologna), P. Greco (Scriba Nanotecnologie Srl Bologna), L. Occhipinti (ST Microelectronics Catania), D. Vuillaume (CNRS, Lille), R. Garcia (CSIC Madrid), H. Gomes (Univ. do Algarve), R. Frycek (Amires Sarl, Neuchatel), E. Cerna and V. Velebny (Contipro Dolni Dobrouc), T. Cramer, S. Casalini, F. Valle (CNR-ISMN Bologna), G. Foschi, C. A. Bortolotti, N. Dorigo (UNIMORE).
This work is supported by EU NMP Project I-ONE Grant Agreement n. 280772
Solid-state assemblies and optical properties of conjugated oligomers combining fluorene and thiophene units
No full textTwo conjugated oligomers, representing elementary segments of fluorene–thiophene copolymers, are compared in terms of the microscopic morphology and the optical properties of thin deposits. The atomic force microscopy morphological data and the solid-state absorption and emission spectra are interpreted in terms of the assembly of the conjugated molecules. The compound with a terthiophene central unit and fluorene end-groups shows well-defined monolayer-by-monolayer assembly into micrometer-long stripe-like structures, with a crystalline herringbone-type organization within the monolayers. Polarized confocal microscopy indicates a strong orientation of the crystalline domains within the stripes. In contrast, the compound with a terfluorene central unit and thiophene end groups forms no textured aggregates and the optical spectra in the solid-state are very similar to those recorded in solution, suggesting that the molecules interact only weakly in the solid. The difference in behaviour between the two compounds most probably originates from their different capability to form densely-packed assemblies of interacting π-systems
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