Academic literature on the topic 'Productions variations'

La vache allaitante utilise près de 70% de l’énergie qu’elle ingère pour son besoin d’entretien. L’importance de cette dépense non productive détermine fortement son efficience d’utilisation de l’énergie. Les nouvelles recommandations alimentaires de l’INRA permettent de mieux quantifier cette dépense non productive afin d’en maîtriser les principaux facteurs de variation. Une base de données a été constituée en regroupant 30 expérimentations, présentant notamment des niveaux alimentaires contrastés (soit au final 101 traitements expérimentaux), menées en stations expérimentales avec des vaches allaitantes. L’Énergie des dépenses non productives (EDNP) exprimée en énergie nette (UFL) a été calculée pour chaque traitement comme la différence entre l’énergie nette ingérée et celles des besoins de lactation, de gestation, et des variations de la masse corporelle par estimation de sa composition chimique. La production de lait moyenne est de 8 kg/jour et prioritaire, quel que soit le niveau alimentaire subit. Estimée par sa composition chimique (respectivement 37 et 21% de lipides), la valeur énergétique de la variation de poids s’élève en moyenne à 2,4 UFL/kg pour les multipares et 1,8 UFL/kg pour les primipares. Les dépenses non productives peuvent s’estimer à partir d’une seule équation dont les variables sont le besoin d’entretien (Eentretien), les conditions d’activité (Iact), la variation de poids (ΔPV) et l’état initial au vêlage (NEC) : EDNP = (Eentretien x Iact) + (0,0073 x ΔPVc x NEC). Le terme interférant (ΔPVc x NEC) traduit les adaptations du métabolisme en situation nutritionnelle contraignante ou pléthorique. Cette quantification nouvelle de l’épargne énergétique associée à la baisse des apports (ou l’inverse) permettra aux éleveurs de mieux gérer l’alimentation de leurs vaches. Les variations de dépenses non productives et leurs nombreux facteurs de variation devront devenir la cible des recherches dans les années à venir.

La teneur et le profil des acides gras (AG) des dépôts adipeux et des muscles influencent la qualité de la viande. Les principales causes de variation de la composition des lipides de ces dépôts ont été étudiées chez les bovins par méta-analyse des données publiées. Le taux de lipides intramusculaires est influencé par le génotype et par le niveau d’ingestion d’énergie. L’accroissement des teneurs en lipides intramusculaires est presque exclusivement constitué de triglycérides (TG). La teneur en phospholipides (PL) varie peu pour un type de muscle donné. Les TG sont plus riches en AG monoinsaturés (AGMI) et en AG saturés (AGS) (TG / PL = 1,9 - 1,3 - 4,5 - 1,2 et 1,1 pour les AGMI - AGS - C14:0 - C16:0 et C18:0, respectivement) mais plus pauvres en AG polyinsaturés (TG / PL : environ 1/15 pour les AGPI) que les PL. Avec des rations contenant des aliments concentrés non supplémentés en matières grasses, les dépôts adipeux et les muscles présentent des teneurs plus faibles en C18:0 et en C18:3 mais plus élevées en C18:1 qu’avec des rations constituées uniquement de fourrage. En outre, dans les lipides intramusculaires, le rapport des AGPI n-6/n-3 est plus élevé avec des aliments concentrés qu’avec du fourrage. Excepté les huiles de palme et les graines de coton, les matières grasses végétales réduisent les teneurs en AGS dans les dépôts adipeux par rapport aux matières grasses d’origine animale. Les graines de lin et de carthame induisent les teneurs en AGPI les plus élevées dans les dépôts adipeux et le lin induit les teneurs les plus élevées en C18:3 dans les muscles. Dans les muscles, les teneurs en C18:2 sont peu influencées par la nature de la matière grasse ajoutée à la ration lorsque celle-ci n’est pas protégée. Les huiles de poisson diminuent les teneurs en C18:0 des muscles et augmentent les teneurs en AGPI à longue chaîne de la série n-3. Une supplémentation de la ration en matières grasses a un effet différent sur la composition en acides gras des triglycérides et des phospholipides des muscles selon la proportion relative des différentes classes de lipides.

Bien que la truie ne connaisse pas d’anœstrus saisonnier, une diminution des performances de reproduction est observée en été et au début de l’automne dans de nombreux pays. La proportion de truies qui tardent à revenir en oestrus après le tarissement augmente tandis que la proportion de truies inséminées qui mettent bas baisse de 5 à 15 %. Ces échecs de gestation sont liés, pour une grande part, à des avortements. Cette baisse des performances peut s’accompagner d’un taux de réforme accru, notamment chez les jeunes femelles. L’influence des saisons est attribuée essentiellement à la photopériode et aux températures ambiantes. La durée quotidienne d’éclairement est perçue par la truie via la sécrétion nocturne de mélatonine par la glande pinéale, comme chez les mammifères à reproduction saisonnière. Cependant, le lien entre mélatonine et sécrétion de LH n’est pas établi chez la truie. La chaleur, si elle induit une hyperthermie chez la mère, affecte la survie des embryons en début de gestation. Pendant la lactation, les truies luttent contre l’hyperthermie en réduisant leur consommation d’aliment et développent des adaptations métaboliques et endocriniennes. Le déficit nutritionnel est connu pour favoriser le risque d’anoestrus après le tarissement. Les adaptations physiologiques liées à la chaleur joueraient aussi un rôle. La conduite d’élevage module les variations saisonnières des performances de reproduction : alimentation et logement des truies, présence du verrat… Une meilleure caractérisation des points critiques dans la gestion de l’atelier de reproduction devrait permettre d’atténuer ces fluctuations saisonnières. Enfin, l’origine de la sensibilité individuelle à la saison mériterait d’être étudiée.

La prairie pâturée, source de nutriments la plus économique pour les vaches laitières, devrait constituer la base de systèmes économes et durables. Dans ces systèmes, la gestion de l’alimentation des troupeaux laitiers au pâturage est un challenge majeur. L’objectif de cet article de synthèse est de présenter et de hiérarchiser les principaux facteurs déterminant des apports énergétiques et azotés des vaches laitières au pâturage en milieu tempéré, afin de mettre en évidence les voies d’actions possibles permettant des performances par vache élevées tout en maximisant l’utilisation et la valorisation de l’herbe par hectare. La gamme de variation possible des besoins alimentaires des vaches et de leur capacité d’ingestion est comparée avec celle de la valeur alimentaire des prairies pâturées et des effets induits par la gestion du pâturage. Ces comparaisons montrent que les vaches fortes productrices ne peuvent pas atteindre leur potentiel de production laitière lorsqu’elles sont nourries à l’herbe seule. Les bilans énergétiques théoriques des vaches peuvent cependant être estimés dans une large gamme de disponibilité et de qualité de prairies. Des modèles prévisionnels permettent aussi de calculer les apports de concentrés nécessaires pour couvrir ces besoins dans une large gamme de pratiques. Les effets de la pression de pâturage, de la complémentation, de l’utilisation des légumineuses ou de la gestion du temps d’accès journalier au pâturage sont notamment présentés et discutés. Il est conclu que les connaissances acquises en termes de régulation de l’ingestion et de la digestion des vaches laitières au pâturage permettent aujourd’hui de définir les voies de maîtrise de l’alimentation du troupeau et des performances des systèmes laitiers bovins herbagers.

Le méthane entérique est formé par les Archea méthanogènes au cours de la dégradation microbienne des aliments dans le rumen, cequi implique que toute variation dans sa production est le résultat d'un changement dans la chaîne alimentaire microbienne. En effetla structure et/ou l'activité de la communauté microbienne fermentaire (bactéries et protozoaires) détermine la quantité et,partiellement, l'utilisation de l'hydrogène, substrat limitant de la méthanogenèse. Les microorganismes méthanogènes ne constituentqu'une petite partie de la biomasse et de la diversité microbienne dans le rumen. Aujourd'hui, l'absence de lien entre la productionde méthane et le nombre des méthanogènes est bien établie sauf lorsque des inhibiteurs spécifiques des Archaea sont employés (vaccin,additifs chimiques). Les variations dans la production de méthane, observées suite à des modifications de l'écosystème microbienou d'un des constituants de la ration, s'expliquent par des changements de diversité et/ou d'activité des Archaea par suite d'unemoindre disponibilité en hydrogène. En effet, les études récentes relient les variations observées dans la production de méthane à desvariations dans l'activité métabolique des méthanogènes et/ou à des changements fins dans leur diversité au niveau de l'espèce oumême de la souche. Ainsi, le développement des stratégies efficaces à long terme pour réduire les émissions de méthane, impliqueinévitablement la bonne compréhension des mécanismes impliqués en considérant l'écosystème microbien dans son ensemble.

Cet article présente de façon synthétique les connaissances acquises par différentes équipes de recherches sur les lois biologiques de variations de la composition corporelle des bovins et les effets des facteurs zootechniques qui permettent de la modifier (génotype, sexe, stade d’abattage, niveau d’alimentation, nature de la ration et facteurs de croissance). Les caractéristiques du tissu musculaire, déterminantes pour la qualité de la viande, et leurs variations sous l’influence des mêmes facteurs sont également développées.

Au cours des dernières années de nombreux travaux ont été réalisés sur les caractéristiques sensorielles des fromages d’AOC, dans le cadre général de l’objectivation de leur liaison à leur terroir (voir Martin et al 2003, dans ce même dossier). De plus en plus, et au-delà des produits AOC, les consommateurs sont à la recherche d’information sur les caractéristiques nutritionnelles des aliments qu’ils consomment, et des produits laitiers en particulier. Les fromages d’AOC sont particulièrement concernés par cette question, dans la mesure où les conditions de leur production peuvent conduire à des caractéristiques nutritionnelles spécifiques. Celles-ci relèvent schématiquement de deux domaines distincts, d’une part les caractéristiques liées à la microbiologie des laits et des fromages et d’autre part celles liées à leur teneur en macro ou micro-constituants d’intérêt nutritionnel (protéines, lipides, vitamines, minéraux…).L’objectif de ce texte est de fournir quelques points de repères sur le rôle des micronutriments et de la microflore sur la santé, sur les liens entre la microflore digestive de l’Homme et son système immunitaire, et sur les actions déjà engagées ou en projet pour identifier et comprendre le rôle de la consommation de fromages au lait cru sur la santé humaine. Voir la suite de l'article à l'adresse :https://www6.inrae.fr/productions-animales_eng/content/download/3821/39526/version/1/file/Prod_Anim_2003_16_4_05.pdf

Soixante deux exploitations laitières des Alpes du Nord ont fait l’objet d’une enquête détaillée concernant à la fois la structure de l’exploitation et du troupeau, la qualité des fourrages et les pratiques alimentaires hivernales et estivales. Ces données ont permis d’analyser les variations de la composition chimique du lait d’une exploitation à l’autre, et en particulier du rapport taux butyreux/taux protéique. Celui-ci a présenté des variations très importantes d’une exploitation à l’autre et d’un mois à l’autre. Selon les exploitations, ces variations sont dues surtout à celles du taux butyreux (cas le plus fréquent), ou plutôt à celles du taux protéique. Les différences de niveau de ce rapport d’une exploitation à l’autre sont difficiles à expliquer par les seules données disponibles : en particulier, compte tenu du type des vaches présentes (Abondance, Tarine et Montbéliarde), l’effet de la race ne semble pas prépondérant. Ce sont les exploitations qui maîtrisent le mieux l’alimentation hivernale et estivale des animaux (et qui présentent par ailleurs des effectifs importants et stables au cours de l’année) qui ont présenté les rapports les plus stables au cours de l’année.

Les changements parfois importants de composition en acides aminés des grain(e)s sont toujours en corrélation avec ceux de leurs taux d’azote. Ils sont décrits par des relations linéaires entre la teneur en chaque acide aminé et le taux d’azote mises en évidence chez 16 espèces cultivées pour leurs grain(e)s. Quelques rappels sont d’abord faits sur les grain(e)s, leurs réserves, la protéosynthèse dont elles sont le siège jusqu’à maturité, ainsi que sur les problèmes soulevés par l’analyse des acides aminés et l’expression des compositions. Les caractéristiques des variations de ces compositions sont discutées, sur le plan tant fondamental que pratique : qu’elles soient dues aux facteurs de l’environnement, à la fumure ou aux conditions culturales ou bien qu’elles soient d’origine variétale, ces variations obéissent strictement aux mêmes types de relations linéaires qui sont donc définies par deux coefficients déterminables expérimentalement pour tout couple correspondant à une espèce et un acide aminé donnés. Le tableau de ces coefficients est donné pour chacune des 16 espèces et pour chacun des 19 acides aminés analysables. Un certain nombre de conséquences nutritionnelles qui en découlent sont discutées, en particulier l’ampleur des variations intraspécifiques des acides aminés dans les protéines des grain(e)s, les variations comparées, en fonction du taux d’azote, des scores nutritionnels par espèce et entre espèces, celle du rapport leucine/isoleucine, ainsi que les changements éventuels dans l’ordre des acides aminés limitants et aussi ceux des coefficients de conversion de l’azote total en protéines réelles. En toute occasion, la connaissance de la composition en acides aminés des lots de grains utilisés dans les rations animales est désormais beaucoup plus simple à établir avec une précision et une sécurité accrues.

A côté de leurs effets sur la motivation sexuelle et la réalisation des conduites de reproduction, les stéroïdes sexuels affectent de nombreux autres aspects du comportement, en particulier les relations sociales, les conduites agressives et la réactivité émotionnelle.Nos connaissances dans ce domaine, en ce qui concerne les Ongulés, ne sont que relativement récentes et souvent fragmentaires, bien que l’importance des comportements influencés par les stéroïdes sexuels soit évidente pour la gestion des espèces domestiques.Il existe des différences sexuelles dans les comportements agressifs, le rôle social qu’exercent les individus, et la réactivité émotionnelle. Ces différences sont sous la dépendance des androgènes. On a en effet pu mettre en évidence des variations des comportements territoriaux et agressifs avec les variations naturelles des niveaux hormonaux. Par ailleurs, des interventions telles que la castration ou des traitements hormonaux chez l’adulte, le jeune ou même in utero, ont confirmé l’influence des stéroïdes sexuels. En particulier, les traitements par des androgènes accroissent l’aptitude à la dominance des mâles et des femelles, et réduisent les réactions de peur dans les deux sexes en situations sociales ou non sociales. De plus, cet effet persiste après l’arrêt des traitements et il est ainsi possible d’influencer à long terme le rang social d’un animal. Le mode d’action des androgènes est cependant mal connu.Compte tenu de la généralisation de l’élevage des mâles en groupes, l’étude des relations entre androgènes et conduites agressives s’avère nécessaire. Par ailleurs, la réactivité émotionnelle qui peut également être influencée par les stéroïdes sexuels, intervient dans l’adaptation de l’animal à son milieu. Son étude, ainsi que celle de ses facteurs de variation, s’inscrit donc dans le cadre des recherches qui visent à développer des techniques respectueuses du bien-être animal.

Le moulage en terre cuite est un procédé de fabrication qui permet de reproduire mécaniquement des objets, à l’aide de matrices. Aussi, en tant que procédé technique, la coroplathie est un exemple de fabrication et de diffusion d’images en nombre.Ma recherche est centrée sur la construction d’une typologie des statuettes en terre cuite de l’époque hellénistique, et principalement celles qui datent des IIIe et IIe siècles av. n.è. en Italie.Celles-ci se caractérisent par un renouvellement iconographique des figurines génériques, sans attribut, dont les plus emblématiques sont les représentations de femmes drapées, appelées aussi « tanagréennes ». En effet, à partir du milieu du XIXe siècle, avec l’apparition sur le marché de l’art des figurines de Tanagra (vers 1870) et de Myrina (vers 1880), le sujet a commencé à attirer l’attention des amateurs d’antiquités puis des scientifiques. Longtemps collectionnées pour elles-mêmes, ces statuettes ont souvent été désolidarisées de leurs environnements archéologiques. En Italie, c’est en grande partie par des études rétrospectives des statuettes conservées dans les musées qu’on parvient aujourd’hui à reconstituer des assemblages et des contextes de découverte (votif ou funéraire). La documentation ayant servi de matière première à cette thèse est disparate. Elle est constituée de catalogues d’objets et de notices de sites éparses dans lesquelles les statuettes sont souvent sous-exploitées. C’est toute la difficulté de cette démarche : ces figurines en terre cuite, à la fois nombreuses, répétitives et souvent fragmentaires suscitent peu d’engouement ; la dynamique de recherche s’attardant davantage sur des lots d’objets mieux conservés ou identifiés. Dans un certain sens, mon travail tente de revaloriser le multiple tant du point de vue de l’artisanat que des usages de ces statuettes dans leurs matérialités religieuses.Le terrain d’enquête de cette étude est celui de l’Italie hellénistique, indépendamment des contextes culturels (italiques, grecs, étrusques, romains) dans lesquels l’historiographie a parfois eu tendance à enfermer la petite plastique en terre cuite. En dépit de leur nombre et de leur diversité, ou plus exactement en raison de ces facteurs, ces figurines restent assez mal connues.Dans ma démarche, j’ai tenté d’échapper aux classements iconographiques et techniques habituels. Ces types tanagréens, largement constitués de figurines féminines drapées mais aussi de quelques sujets mythologiques (Eros, Aphrodite, Athéna, Hermès…) qui par des jeux d’attributs superposés personnalisent ces figurines, ont été observés et analysés en fonction de leur forme et présentés selon une typologie morphologique. Celle-ci a été conçue dans la perspective de proposer une nouvelle grille de lecture et d’interprétation afin de construire des instruments de recherche mieux à même de s’adapter à ces objets dépourvus d’apparentes significations, enchevêtrés dans une sérialité des formes d’où émergent des singularités. La forme et ses variations sont au cœur du sujet, donnant lieu à des développements sur les principales échelles de production de ces figurines et sur l’interprétation des images qu’elles ont véhiculées en fonction de leur environnement topographique, historique et culturel
Terracotta casting is a process of manufacturing that allows the mass production of objects with the help of molds. As a technical process, coroplasty is an example of mass production and diffusion of images.My research is focusing on building a typology for terracotta figurines of the Hellenistic era, more specifically the ones dating back to the 3rd and 2nd Centuries BC in Italy. These generic figurines, with no specific characteristics, feature a renewal in statuette iconography. The most emblematic ones usually represent women wrapped in veils, also called Tanagra figurines.Around the middle of the 19th century, with the apparition of figurines from Tanagra (circa 1870) and Myrina (circa 1880) on the art market, the statuettes began to catch the attention of connoisseurs, then scientists. Collected for themselves for a long time, these figurines have often been torn apart from their archeological environment. In Italy, thanks in great part to a retrospective study of the figurines preserved in museums, we are able to re-establish connections with groups and contexts of discoveries (votive or funerary figurines).The materials gathered for the documentation of this thesis are heterogeneous. It consists of artwork catalogues and notes from various sites where the figurines are often underexposed. The main complexity of this research follows thus: the terracotta figurines, both abundant and repetitive, often incomplete, arouse little enthusiasm; all the energy in research usually focuses mostly on the group of objects best preserved or identified. In a way, my work tries to reassert the value of numbers, as much from the point of view of handicraft as from the different religious functions of the figurines.Italy during the Hellenistic era is the field of investigation for this research, irrespective of cultural context (Italic, Greek, Etruscan or Roman) from which sometimes historiography has a tendency to confine small terracotta figures. Despite their number and variety, or rather because of them, these figurines remain largely ignored. My approach tries to break free from the usual iconographic typologies and technical classifications. I tried to observe and analyze the Tanagra figurines – mostly consisting of veiled feminine silhouettes, but also including some mythologicaltopics (Eros, Aphrodite, Athena, Hermes…) personalized through an array of superimposed attributes – taking into account their shape, and presenting them according to a morphological typology. This typology has been created in the prospect of offering a new frame of reference and interpretation, in order to build tools of research better fitted to these figurines, all lacking in apparent meaning, entangled in the serialization of its shapes, from which sometimes uniqueness emerge. The form and its variations are at the heart of the topic, leading to developments on main production scales, or on the interpretation of the images they conveyed depending on their topographical, historical and cultural environment

Agricultural landscapes have suffered drastic changes as a consequence of management intensification, leading to a decline in biodiversity, specially in Mediterranean olive farms. Among others, homogenization affects the activity levels of bats, an important component of agricultural ecosystems by acting as biocontrol agents against olive pests. To understand how seasonal variations affects bat occurrence and the biocontrol services they provide, we sampled olive groves with different structural complexities over three seasons, coinciding with the peak activity of Prays oleae, one of the major pests of olive production systems. We found strong differences in the response of bats to the structural complexity of olive production systems, being these species-specific and strongly season-dependent. Thus, our results suggest that habitat heterogeneity is of great importance for bat activity, implying that structurally-complex agricultural landscapes could promote higher natural pest control services provided by bats; Variações sazonais no efeito da complexidade estrutural em olivais com diferentes sistemas de produção na atividade de morcegos: implicações para os serviços de controlo natural de pragas Resumo: As paisagens agrícolas sofreram drásticas mudanças por consequência da intensificação da gestão, levando ao declínio da biodiversidade, especialmente em olivais mediterrânicos. Entre outros, a homogeneização afeta os níveis de atividade dos morcegos, os quais apresentam elevada importância nos ecossistemas agrícolas pela sua capacidade de controlo natural de pragas. Para compreender como as variações sazonais afetam a ocorrência destes nos olivais, amostrámos olivais com diferentes complexidades estruturais em três estações, coincidindo com o pico de atividade de Prays oleae, uma das principais pragas dos olivais, para investigar se morcegos poderão atuar no seu controlo. Foram encontradas diferenças nas respostas dos morcegos em relação à complexidade estrutural dos olivais, sendo estas dependentes de cada espécie e da estação. Assim, os resultados sugerem que a heterogeneidade do habitat apresenta grande importância na atividade dos morcegos, implicando que paisagens agrícolas estruturalmente complexas poderão promover serviços de controlo natural de pragas fornecidos pelos morcegos.

Cette étude part de l'intention d'identifier les particularités techniques et économiques des premières phases du magdalénien. Ainsi ce travail prétend apporter de nouveaux éléments pour caractériser les mécanismes évolutifs durant cette période. Pour cela, la corniche cantabrique est un terrain des plus adaptés en raison de la densité des sites magdaléniens mais aussi parce que les premiers moments de cette culture y sont particulièrement bien représentés. Notre analyse se veut une discussion sur la signification chronologique et la dimension géographique des phases "inferieure" et "moyenne" du magdalénien. Ce travail s'appuie dans un premier temps sur l'analyse technologique des industries lithiques (volume II) des séries sur lesquelles repose la structuration du magdalénien cantabrique: Las Caldas (Asturies) ; Rascano (Cantabres) ; Erralla (Guipuzcoa) ; Berroberria et Abauntz (Navarre). Les résultats obtenus sont ensuite confrontés selon un double axe comparatif à la fois diachronique et synchronique (volume I) afin d'interpréter la variabilité de ces industries. Ainsi, cette étude aboutit à l'individualisation des traits techniques et économiques qui définissent deux ensembles chronologiques et tente d'interpréter les variations enregistrées au sein des deux périodes. L'axe diachronique est toutefois privilégié même si l'interprétation de la variabilité synchrone s'effectue en ouvrant le champ de comparaison vers le Portugal, le pourtour méditerranéen, et l'ensemble Gironde-Périgord. L'analyse des industries lithiques nous conduit à établir les relations d'ordre technique et économique qui existent entre le badegoulien et le magdalénien "inférieur" et entre le magdalénien "inférieur" et le magdalénien "moyen" dans le sud-ouest de l'Europe.

At the very beginning of the diploma thesis, we introduce the reader to the issues of BI and controlling of manufacturing companies. Subsequently, we perform an analysis and evaluation of the current state of the selected manufacturing company in terms of variations in production. Then we use MSSQL server and SSAS to create a controlling model. The company will be able to unambiguously and quickly identify weaknesses in production and quickly eliminate them. Finally, we evaluate the real benefits of this project for the company.

Weld quality is essential when manufacturing fatigue-loaded structures. Defective welds are problematic, causing increased lead times, repairs and breakdowns. Over- processing as a result of unnecessary safety margins and poor quality is another issue, leading to a more expensive process and heavier products. Knowledge about what variation in weld quality can be expected in the process enables more efficient problem solving and use of resources. Reduced variation equals increased quality. Consequently, reduced variation is both a manufacturer and customer gain. This thesis studies in what way variation in welding production can be mapped and presented, to guide towards the right improvement actions. A literature study addresses welding, weld quality, measurement methods and variation. Two empirical studies using laser scanning equipment along with staff interviews will then be conducted to develop the method to capture variation in welding. In the journey towards machine learning and elimination of operator decisions, knowledge and understanding of variation in the process is necessary. Concrete results of the empirical studies gave new and valuable information to the company. Further, the method to map, analyse and display variation was believed to be useful in several ways, both at the case company but also at other plants. The results show that knowledge about variation could have a large financial effect. By identifying the areas of over-processing and deficient quality, the process can be optimized to increase productivity. While technical issues such as equipment to collect data can be barriers, soft issues like competence, a common understanding, and visualisation of variation seem just as essential.

This study aims to research variation at a startup company and to understand what methods are necessary to root out and eliminate quality issues. The study is conducted at Biotech AB which is a producer of Bio-instruments as well as bio-ingredients that are produced on site for customers. The company has been concerned with the amount of variation in internal quality coming from the production and the purpose of this study is to find what is causing the variations and what preventative actions need to be taken. This study has been a mix between a quantitative and a qualitative study with its base being around the records of errors given through quality logs. Several interviews were made as well as observations in working procedures and working instructions. The results showed that five major issues were causing the most concern and unnecessary cycles in production, namely featured parts and human error also cause these variations. The interviews indicated that processes need to be managed better and faster due to the rapid pace of the company growth. They also indicate that the communication doesn't always work and needs to flow freely in both directions. The level of waste is quite high in forms of physical waste and time wasted due to cycles in production. Lean thinking needs to be implemented and 5s needs to be made aware of to give everyone a quality and waste-free working ethic from the ground up. Many of these issues could be solved by implementing a quality perspective by giving constant feedback according to TQM.

During the past decades, there have been an acceleration of customers’ needs of customized products. This have pressured many companies in offering customized products in order to reach customer satisfaction and keep growing and expanding their market share. Nowadays the competitive pressure between companies with the same product segment is increasing and the market requirements are changing rapidly. To handle this competition, many manufacturing companies are focusing on mass customized production. However, mass customization has been a topic of interest for many researchers. The focus has been in studying and understanding the complexity and the constrains that a company encounter when dealing with mass customized production in mostly the automotive industry. One of the constrains that have been less highlighted by researchers were the effects that mass customized production has on the output variation of production lines. Therefore, the purpose of this thesis is to investigate how to minimize output variations in mass customized production within assembly lines. To do that the researchers focused on studying the output variation in whitegoods industry instead of the automotive industry that captures most of the existing research. The study includes two main research questions. The first question was to identify the factors that affect the output variation in mass customized production. While the second question was to identify applicable solutions that can be used to stabilize the output. To ensure the reliability and validity of the research findings, the researchers used multiple case study combined with literature reviews. To answer the research questions several data collection techniques were used in the multiple case study conducted on two lines. Those data collection techniques were participating observations, document reviews, a semi-structured interview and many conversations with the affected persons. The findings from the case study for research question one showed consistency with the theories described in the theoretical background. This was evident because similar problems when it comes to output variations were defined in the theories. One problem was about the simplification of assembly line balancing problem that was evident in both case studies. This was an effect of the missing product family classification which created a high output variation because of the use of only one line balancing for all product variants. Another problem identified included functionality problems of machines because of performing wrong assembly or the use of the wrong component. There was as well the problem of missing or delayed components which was an effect of the lack of structure in the material picking and the deliveries performed for both lines. A combination of those factors created the experienced output variation on both lines. To deal with those problems and minimize the output variation, a solution approach was defined in the second research question. This approach was created together with the case company with the help of the theoretical background and it presents several steps to follow when attacking and resolving similar problems as presented above. The most important conclusion of this thesis is that, when dealing with output variation in mass customized production where people are performing the assembly, it is essential to provide the right conditions for them to ensure that they have the right knowledge base to perform the requested assembly.

Pour les communautes recifales dominees par les coraux et les poissons, le zooplancton constitue un potentiel nutritif insuffisamment etudie et source de controverses. La presente etude situe le zooplancton dans l'ecosysteme recifo-lagonaire et pose le probleme des limites de ce dernier. Les variations de composition et d'abondance du plancton de ces milieux sont etudiees dans le temps et dans l'espace a l'aide de filets et de pieges a emergence; les recherches concernent cinq lagons differant par leur degre d'ouverture sur l'ocean. Dans le temps, les variations nycthemerales depassent en ampleur les variations lunaires et les variations annuelles; elles constituent un trait caracteristique du plancton de ces milieux, particulierement dans les zones soumises a un fort hydrodynamisme. Dans l'espace, l'abondance et la repartition des organismes varient avec le degre d'ouverture des lagons; deux types d'heterogeneite se rencontrent: l'un est lie a l'hydrodynamisme de surface, l'autre a la vitesse de renouvellement de l'eau des lagons. L'etude des transferts planctoniques entre l'ocean et le lagon, d'une part dans un lagon de recif-bariere, d'autre part dans un lagon d'atoll montre, au terme des bilans, que le premier est importateur et le second exportateur; l'inclusion de la pente externe du recif dans l'ensemble recifo-lagonaire est necessaire pour comprendre ce bilan et ceci ouvre des perspectives nouvelles sur la structure et le fonctionnement de ces ecosystemes coralliens

The capability of modulating power and heat productions by steam injection in a recuperative cycle gas turbine was investigated. A combined heat and power system using a current state-of-the-art recuperative cycle gas turbine was modeled. Variations in engine performance characteristics due to steam injection were examined. A full off-design analysis was carried out to investigate not only the performance change but also the variation in engine operation caused by the steam injection. Impact of injecting steam at different locations (recuperator and combustor) was investigated. A special attention was given to the change in the compressor surge margin, and a couple of operations that secures a minimum surge margin were comparatively analyzed. Bypass of turbine exhaust gas around the recuperator to increase steam generation was simulated and its usefulness in controlling heat to power ratio was demonstrated. Variations in electric power and thermal energy productions in response to the modulations of injection ratio and gas bypass were presented for a wide ambient temperature range.

The ever increasing consumption of non-renewable fossil fuels for global economic development leads to serious energy crisis and environmental pollution. Consequently, new alternative fuels and high-efficiency combustion are required to aid the sustainable development of human society. The present paper took the RP-3 aviation kerosene and coal-to-liquid synthetic aviation fuel (manufactured through the Fischer Tropsch process., FT) for object, and experimentally investigated the influences of pressure, inlet temperature and equivalence ratio on the productions of NOx and CO in a jet stirred combustion reactor. The tests were performed under the pressures of 2bar and 3bar, and inlet air temperatures of 550K and 650K, respectively. The equivalence ratio ranged from 0.5 to 1.2. The mean residence time was approximately 8ms. Probe sampling followed by on-line emissions analyzer permitted to measure the concentration of the products. The experimental results show that these two fuels obey the same law with the variations of pressures, inlet temperatures and equivalence ratios. The NOx production increases with the pressure and inlet temperature increasing. The CO decreases with the pressure increasing, while slightly increases with the inlet temperature increasing. Numerical simulations were also performed to investigate the combustion products of these two fuels in the jet stirred combustion reactor. Two PSRs were introduced to simulate the jet flame region and post flame in the recirculation region, respectively. The combustion products of second PSR (PSR2) agreed well with the experimental results by regulating the volume ratio of first PSR (PSR1). Based on the reaction pathway analysis of NO production in present state, it is considered that for these two fuels the NOx production is led by the thermal NO above the equivalence ratio of 0.65, while by the N2O at lower equivalence ratios. With the application of the present alternative fuel and its reaction mechanism, the experimental results of aviation kerosene and Coal-to-Liquid synthetic aviation fuel can be predicted well within a certain state, which requires a further verification in a wider range. Furthermore, the numerical results show that the NO release is insensitive to the reaction components within present experimental states.

In this investigation is approached method for assessing and evaluation of colour repeatability and variation for digital electrophotography printing presses. Two of most popular midlevel electrophotography colour production presses were chosen. These presses are widely used in printing houses for the printing of book covers, posters, etc. in small circulations. The similar perception of quality of digital production to the offset printing quality (ISO 12647-2:2013 ) is required from most of the clients of printing houses, publishers, etc. One of the problems of midlevel electrophotography colour production presses are variations of colours in the printing run and variations of colours during the time – weeks, months, years. The variation degree depends on many factors like – the precision of internal calibration method and types of sensors during the printing run, quality of used materials, calibration precision made by press operator, temperature and humidity variation, etc. (Kachin, Spiridonov, 2000) Specially designed for experiment test forms have been printed on two of most widely used materials for book covers, business cards, etc. – 300 g/m2 matt-coated board and 300 g/m2 offset uncoated board. The evaluation method is based on colorimetrical and densitometrical measurements (Kachin, Spiridonov, 2004) of 100 continuous printed sheets. The experiment was repeated in different time periods -between 6 hours and 4 months, to collect data for colour variation between reprinting the same test images in the time.

Abstract Variation modeling is used in design to predict and diagnose potential quality problems. Most variation modeling assumes the parts are rigidly assembled. However, in some cases, this assumption is invalid. For example, when hydraulic tubes are assembled into aircraft structures, the compliance of the tube facilitates assembly. If the tubes were rigid, they cannot be assembled, i.e., the variations of the tubes and structures are too great. Despite the importance of compliance in assembly, it is typically not explicitly modeled during design. This paper proposes a new method to directly predict the assemblability of any tube design with minimal dependence CAD/FEM modeling and simulation. The model includes a variation model for the tubes and aircraft, compliance model and assembly model. It can be used during design to improve yields.

A robust optimization of an automobile valvetrain is presented where the variation of engine performances due to the component dimensional variations is minimized subject to the constraints on mean engine performances. The dimensional variations of valvetrain components are statistically characterized based on the measurements of the actual components. Monte Carlo simulation is used on a neural network model built from an integrated high fidelity valvetrain-engine model, to obtain the mean and standard deviation of horsepower, torque and fuel consumption. Assuming the component production cost is inversely proportional to the coefficient of variation of its dimensions, a multi-objective optimization problem minimizing the variation in engine performances and the total production cost of components is solved by a multi-objective genetic algorithm (MOGA). The comparisons using the newly developed Pareto front quality index (PFQI) indicate that MOGA generates the Pareto fronts of substantially higher quality, than SQP with varying weights on the objectives. The current design of the valvetrain is compared with two alternative designs on the obtained Pareto front, which suggested potential improvements.

Climate change is already impacting farm and forest lands throughout the northeastern United States. Temperatures are increasing and more rain is falling all at once with dry periods in between. With these changes comes greater variation and uncertainty in crop and livestock production. Without modifying management, agricultural profits may decline

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.