Aufgrund der stetig wachsenden Anforderungen hinsichtlich Gewichtsreduzierung und Funktionsintegration, besonders im Bereich des Automobilbaus, werden traditionell aus metallischen Werkstoffen gefertigte Komponenten immer häufiger durch Kunststoffbauteile substituiert. Dem entgegen steht derzeit die Tatsache, dass, trotz hohen Prozessverständnisses und des Wissens um die Prozess-Struktur-Eigenschafts-Beziehungen beim Vibrationsschweißen, die theoretisch erzielbaren Schweißnahtfestigkeiten, von 90 % bis 100 % des unverstärkten Grundmaterials, in der industriellen Serienfertigung bei weitem nicht erreicht werden. Die Komplexität eines industriell gefertigten Bauteils wird an Plattenprüfkörpern simuliert. Die Ergebnisse der Schweißversuche zeigen, dass unterschiedliche Wandstärken im Schweißnahtbereich, Bauteilverzug und unterschiedliche Schwingrichungen innerhalb einer Schweißnaht zu ungleichmäßigen lokalen Prozessbedingungen währenden des linearen Vibrationsschweißprozesses führen. Diese hinterlassen lokale Schwachstellen, welche das Gesamtbauteilversagen bestimmen. Durch alternative Prozessführungsstrategien, wie das Hochdruckanfahren und die IR-Vorwärmung, können diese Schwachstellen reduziert und die Gesamtbauteilfestigkeit angehoben werden. Dies wird am Beispiel des Bauteilverzugs veranschaulicht. / Due to the increasing demands for weight reduction and integration of function, especially in the field of automotive, components made of metallic materials are increasingly being substituted by components made of thermoplastic materials. In contrast to this there is currently the fact that, despite the high process understanding of the vibration welding and the knowledge of the process-structure-property relationships, the theoretically achievable weld strengths of 90 % to 100 % of the unreinforced base material strength are far to be achieved in industrial series production. The complexity of an industrially manufactured component is simulated by using plate test specimens. The results of the welding experiments show that different wall thicknesses in the weld area, component warpage and different friction angle within the weld leads to nonuniform local process conditions during linear vibration welding process. This results in local weak spots, which reduce the total component strength. These local weak spots can be reduced by using alternative process strategies, such as in-process pressure variation and IR preheating. So not only the local strengths but also the total component strength will be increased. This is shown on the example of component warpage.

Darbe analizuojama šeimos santykių raiška vaikų piešiniuose. Tyrime dalyvavo 5 - 9 metų vaikai: 20 vaikų augančių darniose šeimose ir 20 vaikų, augančių krizę išgyvenančiose šeimose. Objektyvesnei, papildomai informacijai gauti apie vaikus, jų šeimas, buvo atliktas interviu su šešiomis pedagogėmis. Vaikai piešė savo ,,Šeimos“ ir ,,Gyvūnų šeimos“ piešinius. Tyrime buvo siekiama įvertinti ir palyginti šeimos narių tarpusavio santykius darniose ir krizę išgyvenančiose šeimose. Tyrimo išvados: 1. Vaikų piešiamuose ,,Šeimos“ ir ,,Gyvūnų šeimos“ piešiniuose, kaip realybė ar siekiamybė, atsispindi šeimos narių tarpusavio santykiai. Piešiniai gali būti naudojami emocinių ryšių šeimoje įvertinimui. „Šeimos“ piešiniuose labiau atsispindi ir atsiskleidžia reali šeimos situacija ir šeimos narių emociniai ryšiai, o ,,Gyvūnų šeimos“ piešiniuose - vaikų lūkesčiai, troškimai, susiję su norima šeima ir norimais šeimos narių santykiais. Ši tendencija nurodoma ir kitų autorių darbuose. 2. Darniose ir krizę išgyvenančiose šeimose augančių vaikų piešinių analizės rezultatai nevienareikšmiški. Abiejų tipų šeimose yra ir palankių, ir nepalankių emocinių ryšių apraiškų. Daugumai darniose šeimose augančių vaikų būdingi palankūs emociniai ryšiai su šeimos nariais, kai kuriems - kiek silpnesni ryšiai su broliais ir seserimis. Krizę išgyvenančių šeimų daugumos vaikų emociniai ryšiai su šeimos nariais yra silpnesni, daugiau negatyvių ir prieštaringų santykių. Būdingas... [toliau žr. visą tekstą] / In this master thesis the expression of family relationships in the drawings of children is analyzed. The research included 5 - 9 year olds: 20 children growing cohesive families and 20 children growing up in families in crisis. In order to provide more objective additional information about the children and their families, the interview with six educators was conducted. Children drew their own “family” and “animal family" drawings. The study was designed to evaluate and compare the relationships between family members in harmonious families and families in crisis. Main conclusions of the research: 1. In children’s own “family” and “animal family" drawings, as reality or aspiration reflecting family relationships. Drawings can be used as valuation of emotional communication in the family. "Family" drawings express and reveal the real situation of the family and family relationships, and “animal family "drawings - children's expectations, desires associated with the desired family and desired family relationships. This tendency is indicated in others authors researches. 2. In harmonious and experiencing a crisis families the research conclusions of children's drawings are mixed. Both types of families have both favorable and unfavorable manifestations of emotional communication. Most in harmonious families living children characterized by favorable emotional relations with family members, some of whom - weaker relationships with brothers and... [to full text]

Per XX a. paskutinius dešimtmečius viešojo ir privataus sektorių santykis gerokai pasikeitė. Tradiciškai viešojo sektoriaus veiklos sričiai priskirtų paslaugų teikimui ar infrastruktūros modernizavimui ir plėtimui imta naudoti viešojo ir privataus sektorių partnerystę. Koncesija yra vienas iš partnerystės modeliu. Ją galima apibūdinti kaip susitarimą tarp viešojo ir privataus sektorių, kurio tikslas sujungti viešuosius ir privačius išteklius, siekiant realizuoti viešosios politikos tikslus. Lietuvoje koncesijos, lyginant su kitomis valstybėmis, yra naujas reiškinys, neturintis tradicijų ir patirties. Viešosios institucijos retai nusprendžia investicijas pritraukti koncesijos sutarčių pagrindu. Šio darbo objektas yra koncesija. Tikslas - išnagrinėti koncesijų taikymo galimybes Lietuvoje. Tikslo pasiekimui iškelti trys uždaviniai, kurie nulėmė darbo struktūrą. Pirmojoje darbo dalyje analizuojant mokslinę literatūrą ir taikant apibendrinimo metodą nagrinėjamos ekonominės – socialinės viešojo ir privataus sektorių partnerystės atsiradimo prielaidos ir partnerystės sąvoka. Antrojoje dalyje, analizuojant viešojo ir privataus sektorių partnerystės taikymo galimybes atliekama mokslinės literatūros ir informacinių šaltinių analizė, taikomas klasifikavimo ir sisteminimo metodas. Trečiojoje darbo dalyje vertinant koncesijų taikymo galimybės atliekamas kokybinis tyrimas, suformuluojami pagrindiniai klausimai, atliekama norminių teisės aktų ir informacinių šaltinių lyginamoji analizė... [toliau žr. visą tekstą] / Infrastructure has been traditionally viewed as a natural monopoly under the management, control, financial responsibility of the central and local government. However, various countries of the world have shown a growing interest in Concessions (one of the Public Private Partnership model) over the last two decades. Concession is arrangement in which the public and private sectors join together to produce and deliver goods and services. It is a sufficiently new phenomenon in Lithuania and some shortcomings are noticeable in its application. The object of this thesis is Concession. The aim of work is to analyze possibilities to apply the concession in Lithuania. Three tasks were established for the realizing the goal meanwhile determining the structure of thesis. In the first part of thesis there is analysed Public Private Partnership, as phenomena, using analysis of academic literature. In the second part, by using analysis of special and statistical literature, there are analysed subjects influencing Public Private Partnership and experience of various countries of the world in the developing Partnership policy. Situation in Lithuania by excluding main prerequisites for developing concessions is analysed in the third part, using qualitative analysis of academic and special literature, laws, conference materials, comparative, case study methods and quantitative analysis by carrying out a survey of Municipalities opinion. Analysis of theoretical and practical aspects has shown... [to full text]

Akcijų pirkimo – pardavimo sutartis – vienas iš būdų perleisti ir įgyti verslą. Įstatymu specifiškai nėra reguliuojami sandorio sudarymo ir vykdymo klausimai ir jam yra taikomos bendrųjų pirkimo – pardavimų normų nuostatos, numatytos CK. Praktikoje šalys pačios sukūrė tam tikras specifines šios sutarties sudarymo, vykdymo taisykles. Kadangi efektyvių pirkėjo teisių gynybos būdų įstatymai nenumato akcijų pirkimo – pardavimo sutarties kontekste, praktikoje yra suformuluotos tam tikros taisyklės, kurios yra pirkėjo teisių apsaugos garantija bei efektyvaus pažeistų teisių gynybos užtikrinimo priemonė. Pirkėjo teises apsaugančios priemonės yra pateikiamos pareiškimų ir garantijų pavidalu. Pateikdamas pareiškimus ir garantijas, pardavėjas patvirtina, kad neegzistuoja tam tikros aplinkybės ir kad jos neišnyks arba suteikiami užtikrinimai, kad tam tikros aplinkybės atsiras per tam tikrą laikotarpį.. Tačiau tam, kad pirkėjas žinotų, kokių garantijų ir kokia apimtimi yra būtina reikalauti iš pardavėjo, pirkėjas privalo elgtis protingai ir pats dėti pastangas tam, kad patikrinti įsigyjamos bendrovės būklę bei nustatyti vertę. Tuo pačiu pardavėjas turi pareigą atskleisti visą informaciją, kuri yra esminė pirkėjui ir kuri gali daryti įtaką akcijų vertei ir pardavėjo apsisprendimui dėl sandorio sudarymo. Pardavėjui neįvykdžius šios pareigos, pirkėjas įgyja teisę pasinaudoti sutartyje numatytais teisių gynimo būdais ir kompensuoti padarytą žalą. Nors akcijų sandoryje yra įprasta numatyti... [toliau žr. visą tekstą] / The share purchase agreement is the one of the methods to transfer and to acquire the business. The laws do not provide the specific regulation the share purchase agreement – it is regulated by the general provisions of sale – purchase provided by civil code. However the parties of the agreement have created specific provisions which regulate the conclusion and execution of the share purchase agreement. Accordingly to the fact that the laws are not the mean to warrant the right of the buyer, the practice has formulated the guarantee of the seller‘s rights and effective mean to compensate the losses. These means are formulated as representations and warranties. By giving these representations and warranties, the seller warrants that particular circumstances shall not occur or shall occur within the time provided by the parties. In order to know the warranties which shall be given by the seller and the scope of these warranties, the seller must examine the target and to calculate the value of it. The seller is obliged to disclose all information which shall be essential to the buyer. If this obligation of the seller is in breach, the seller is endowed to invoke all measures to protect its rights. Despite the fact that the share purchase agreement provides different measures, the buyer shall have the right to demand damages and other legal means. According to the Lithuanian case-law, provisions regarding defect of the object of the agreement are not applied to the shares... [to full text]

Marine scientific research has not lost any of its significance for the world of today and might become even more important for the future as the knowledge in this area will be crucial for management decisions in most areas of human life. Lithuania being the coastal state should be strongly motivated to create favourable conditions for carrying out MSR. The provisions of Part XIII, 1982 UNCLOS, set out specific rights and obligations for coastal and researching States and provide guidelines on how these rights and obligations should be implemented through negotiated access by foreign research vessels into the maritime zones under coastal State sovereign rights and jurisdiction. However, there is no evidence of successful UNCLOS implementation into national law of the Republic of Lithuania. The MSR regime remains nominal for lack of practical implementation. Though the UNCLOS is considered to represent the predominant international MSR regime, there are still provisions requiring a liberal interpretation, which could be enabled both by States enacting appropriate formulations and procedures in their national legislation and by commissions and international organizations developing guidelines and standardized procedures. The study has been structured in three parts which are further outlined in chapters representing the most relevant issues of the topic under discussion. Part 1 explores the historical development of marine science regulation indicating the origin and... [to full text]

The theme of the thesis An Implementation of the Policy on Equal Opportunities in Lithuania is relevant and important, because the implementation of this policy in Lithuania is highly associated with adoption of Western democratic values, integration into Western international organizations and striving to achieve international communities set the standards in fields of human rights and equal opportunities.

Etiniai bendravimo aspektai tarp gydytojo ir paciento visuomet buvo ir išlieka viena svarbesnių visuomenės aukšto išsivystymo ir sąmoningumo moralinių aspektų. Faktoriai apibūdinantys paciento požiūrį į gydytoją lemia lygiavertį bendravimą tarp paciento ir gydytojo, o gydytojo sąmoningumo, žmogiškųjų sąvybių ir darbo kokybės gerinimas yra vienas iš prioritetinių sveikatos sistemos priežiūros uždavinių. Šiuolaikinės sveikatos priežiūros paslaugų teikimas turi būti atliekamas tokiame lygmenyje, kad nebūtų pacientų nusiskundimų gydytojais, o pastarieji nevengtų „rizikingų“ pacientų. Šiame darbe analizuojami faktoriai, turintys arba galintys turėti įtakos gydytojo ir paciento tarpusavio santykiams, pateikiamos rekomendacijos būtinių veiksnių ar faktorių kuriuos būtina įgyvendinti siekiant abipusiai naudingo gydytojo ir paciento bendravimo. Darbo tikslas - Įvertinti gydytojų nuomonę apie bendravimo su pacientais ypatumus ir etinius šio bendravimo aspektus gydytojo santykiuose su pacientu. Tyrimo metodai. 2011 metais „Gydytojų sąjungos“ organizuotose specializuotuose mokymose Druskininkų ligoninėje buvo įvykdyta anoniminė anketinė gydytojų apklausa, kurios metu buvo apklausta 2440 įvairių specialybių gydytojų. Anketiniai duomenys buvo apdoroti ir analizuojami naudojant statistinį duomenų analizės paketą SPSS 17.0. Hipotezės apie dviejų požymių nepriklausomumą buvo tikrinamos naudojant chi kvadrato (χ2) kriterijų (97). Rodiklių skirtumai laikyti statistiškai reikšmingais, kai p<0,05... [toliau žr. visą tekstą] / Ethical aspects of doctor-patient communication have always been and remain some of the major moral issues of high public development and awareness. The factors characterizing the patient's attitude to the doctor determine the equivalent communication between the patient and the physician, and physician’s awareness, human qualities and quality improvement is one of the priority health care challenges. Delivery of modern health care services must be performed at a level that would not be patient complaints about doctors, but they do not avoid "risky" patients. This paper analyzes the factors which have or may have an impact on doctor-patient relationships, presents recommendations on necessary factors or actions that need to be implemented in order to establish a mutually beneficial doctor-patient communication. Aim of the work: to evaluate doctors opinion regarding the doctors-patients communication peculiarity and ethical aspects of such communication in doctors relationships with patient. Methods of the research: the anonymous questionnaire survey of physicians was organised in Druskininkai hospital at 2011, on the specialized trainings organised by “Medical Association”. 2440 doctors of various specialties participated in the survey. The questionnaire data were processed and analyzed using the statistical data analysis package SPSS 17.0. Hypotheses about the independence of two signs were tested using the chi-square (χ2) test (97). Differences of indicators were considered... [to full text]

Le risque d’explosion des mélanges H2/air revêt toujours une importance cruciale pour la gestion des accidents graves dans les centrales nucléaires. Des critères expérimentaux ont été proposés dans les années 2000 par Dorofeev et al. afin de déterminer les conditions nécessaires à l’accélération de flamme et à la TDD. Ce travail de thèse a l’objectif de mieux comprendre les mécanismes d’accélération des flammes de prémélange H2/air et de fournir une solide base de données expérimentales pour la validation des codes utilisés pour les études de sûreté. Les expériences ont été menées dans un tube muni d’obstacles (taux de blocage entre 0.3 et 0.6) avec un diamètre interne de 12 cm et une longueur d’environ 5 m. Les effets de la pression initiale et de la dilution en azote sur des mélanges pauvres en H2 ont été étudiés. Les résultats montrent que la pression favorise l’accélération seulement pour les mélanges les plus réactifs et que la surpression induite par la combustion est directement proportionnelle à la pression initiale. Les interactions flamme-choc ainsi que les instabilités thermo-diffusives jouent un rôle important sur la propagation de flamme. Une nouvelle technique a été développée dans le but d’obtenir une représentation plus fine du profil de vitesse de flamme. Des mesures d’absorption IR résolues dans le temps ont été effectuées en dopant le mélange avec un alcane. Le profil de vitesse a été obtenu en mesurant la variation d’extension du gaz frais pendant l’avancement de la flamme. Enfin, des analyses préliminaires ont été menées pour la conception d’un nouveau dispositif expérimental pour l’étude des effets de la combustion sur des structures en acier inox. / Flame acceleration and explosion of hydrogen/air mixtures remain key issues for severe accident management in nuclear power plants. Empirical criteria were developed in the early 2000s by Dorofeev and colleagues providing effective tools to discern possible FA or DDT scenarios. The objectives of the present work are to better understand the mechanisms of acceleration for premixed H2/air flames and to provide a solid base of experimental data for the validation of the codes used for safety analyses. The experiments were performed in an obstacles-laden tube (blockage ratio between 0.3 and 0.6) with 120 mm internal diameter and about 5 m length. The effects of the initial pressure and the nitrogen dilution on lean H2 mixtures have been studied. The results show that pressure promote flame acceleration only for highly reactive mixtures. Moreover, the overpressure induced by the combustion is directly proportional to the initial pressure. Besides, flame-shock interactions and thermo-diffusive instabilities play an important role in flame acceleration. A new technique to track the flame position along the tube has been developed in order to obtain a finer representation of the flame velocity profile. The method consists in performing time-resolved IR absorption measurements by doping the mixture with an alkane. The velocity profile is then derivedby measuring the variation of the extension in depth of the unburnt gas along the tube axis. Finally, analyses on the effects of combustion generated loads on stainless steel structures were performed in order to provide preliminary results for the design of a new experimental device.

Nous avons caractérisé différents cristaux piézoélectriques de Langatate La3Ga5.5Ta0.5O14 (LGT), de différentes couleurs afin d’évaluer l’influence des défauts sur la qualité de dispositifs du domaine Temps-Fréquence (résonateurs acoustiques).Nous avons étudié la composition de ces cristaux dont les variations autour de la composition stoechiométrique sont surtout dues à l’évaporation du Ga2O au cours de la croissance compensée par un excès de Ga2O3 dans le mélange initial. Pour déterminer cette composition, la technique ICP-AES, précédée par une mise en solution par fusion alcaline, est la plus fiable.La présence d’impuretés chimiques, telles que les éléments métalliques ou les terres rares, liée à la pureté des oxydes de base, au frittage de la charge dans un creuset alumine… est étudiée. Nous expliquons ainsi la nature des centres colorés qui évolue selon l’atmosphère de tirage ou lors d’un recuit particulier.C’est ainsi que nous avons déterminé certaines propriétés de LGT permettant l’obtention de dispositifs comme les résonateurs à ondes de volume dont le produit Q.f est supérieur à celui des résonateurs à quartz. Pour cela, nous montrons notamment qu’il est nécessaire que :- la composition du cristal soit la plus proche possible de la stoechiométrie,- la résistivité électrique soit la plus grande possible,- l’étude spectroscopique ne révèle aucune absorption dans le domaine du visible.Dans ces conditions, le facteur de qualité Q d’une résonance à 10 MHz peut être de 1.44 million au point d’inversion de la courbe fréquence-température (1.35 pour le quartz) mais qu’il diminue notablement pour atteindre 0.35 million si nous pratiquons un recuit sous air à 1000°C pendant 48 h. / We have characterized Langatate piezoelectric crystals La3Ga5.5Ta0.5O14 (LGT), differently colored in order to evaluate the defects influence on the quality of Bulk Acoustic Waves resonators for the Time and Frequency domain.We have analyzed the composition of crystals whose variations around stoichiometric composition are mainly due to the evaporation of the Ga2O during growth compensated by adding an excess of Ga2O3 in the initial mixture. Among different techniques, the ICP-AES spectrometry, preceded by a dissolution by alkaline fusion seems to be the most accurate technique to determine the composition.The inevitable presence of chemical impurities, such as metallic elements, rare earth… linked to the purities of the raw materials, to the sintering of the load in an alumina crucible… is also studied. We try to explain in particular the nature of the color centers that evolve according to the growth atmosphere or during a particular annealing.So, we conclude by a list of necessary properties to obtain BAW resonators exhibiting a Q.f product higher than quartz. For this, we establish that it is necessary that:- the crystal composition is as close as possible to the stoichiometric composition,- the electrical resistivity is the highest possible,- the spectroscopic study does not reveal any absorption band in the visible domain.In these conditions, we were able to highlight that the quality factor of a 10 MHz resonance is of 1.44 million at the inversion temperature of the frequency-temperature curve (1.35 for the quartz crystal in the same conditions), but that this one decreases significantly to reach 0.35 million if we perform an annealing under air at 1000 °C during 48 hours.

La recherche d'information nécessite la mise en place de stratégies qui consistent à (1) cerner le besoin d'information ; (2) formuler le besoin d'information ; (3) repérer les sources pertinentes ; (4) identifier les outils à exploiter en fonction de ces sources ; (5) interroger les outils ; et (6) évaluer la qualité des résultats. Ce domaine n'a cessé d'évoluer pour présenter des techniques et des approches permettant de sélectionner à partir d'un corpus de documents l'information pertinente capable de satisfaire le besoin exprimé par l'utilisateur. De plus, dans le contexte applicatif du domaine de la RI biomédicale, les sources d'information hétérogènes sont en constante évolution, aussi bien du point de vue de la structure que du contenu. De même, les besoins en information peuvent être exprimés par des utilisateurs qui se caractérisent par différents profils, à savoir : les experts médicaux comme les praticiens, les cliniciens et les professionnels de santé, les utilisateurs néophytes (sans aucune expertise ou connaissance du domaine) comme les patients et leurs familles, etc. Plusieurs défis sont liés à la tâche de la RI biomédicale, à savoir : (1) la variation et la diversité du besoin en information, (2) différents types de connaissances médicales, (3) différences de compé- tences linguistiques entre experts et néophytes, (4) la quantité importante de la littérature médicale ; et (5) la nature de la tâche de RI médicale. Cela implique une difficulté d'accéder à l'information pertinente spécifique au contexte de la recherche, spécialement pour les experts du domaine qui les aideraient dans leur prise de décision médicale. Nos travaux de thèse s'inscrivent dans le domaine de la RI biomédicale et traitent les défis de la formulation du besoin en information experte et l'identification des sources pertinentes pour mieux répondre aux besoins cliniques. Concernant le volet de la formulation et l'analyse de requêtes expertes, nous proposons des analyses exploratoires sur des attributs de requêtes, que nous avons définis, formalisés et calculés, à savoir : (1) deux attributs de longueur en nombre de termes et en nombre de concepts, (2) deux facettes de spécificité terme-document et hiérarchique, (3) clarté de la requête basée sur la pertinence et celle basée sur le sujet de la requête. Nous avons proposé des études et analyses statistiques sur des collections issues de différentes campagnes d'évaluation médicales CLEF et TREC, afin de prendre en compte les différentes tâches de RI. Après les analyses descriptives, nous avons étudié d'une part, les corrélations par paires d'attributs de requêtes et les analyses de corrélation multidimensionnelle. Nous avons étudié l'impact de ces corrélations sur les performances de recherche d'autre part. Nous avons pu ainsi comparer et caractériser les différentes requêtes selon la tâche médicale d'une manière plus généralisable. Concernant le volet lié à l'accès à l'information, nous proposons des techniques d'appariement et d'expansion sémantiques de requêtes dans le cadre de la RI basée sur les preuves cliniques. / The research topic of this document deals with a particular setting of medical information retrieval (IR), referred to as expert based information retrieval. We were interested in information needs expressed by medical domain experts like praticians, physicians, etc. It is well known in information retrieval (IR) area that expressing queries that accurately reflect the information needs is a difficult task either in general domains or specialized ones and even for expert users. Thus, the identification of the users' intention hidden behind queries that they submit to a search engine is a challenging issue. Moreover, the increasing amount of health information available from various sources such as government agencies, non-profit and for-profit organizations, internet portals etc. presents oppor- tunities and issues to improve health care information delivery for medical professionals, patients and general public. One critical issue is the understanding of users search strategies and tactics for bridging the gap between their intention and the delivered information. In this thesis, we focus, more particularly, on two main aspects of medical information needs dealing with the expertise which consist of two parts, namely : - Understanding the users intents behind the queries is critically important to gain a better insight of how to select relevant results. While many studies investigated how users in general carry out exploratory health searches in digital environments, a few focused on how are the queries formulated, specifically by domain expert users. We address more specifically domain expert health search through the analysis of query attributes namely length, specificity and clarity using appropriate proposed measures built according to different sources of evidence. In this respect, we undertake an in-depth statistical analysis of queries issued from IR evalua- tion compaigns namely Text REtrieval Conference (TREC) and Conference and Labs of the Evaluation Forum (CLEF) devoted for different medical tasks within controlled evaluation settings. - We address the issue of answering PICO (Population, Intervention, Comparison and Outcome) clinical queries formulated within the Evidence Based Medicine framework. The contributions of this part include (1) a new algorithm for query elicitation based on the semantic mapping of each facet of the query to a reference terminology, and (2) a new document ranking model based on a prioritized aggregation operator. we tackle the issue related to the retrieval of the best evidence that fits with a PICO question, which is an underexplored research area. We propose a new document ranking algorithm that relies on semantic based query expansion leveraged by each question facet. The expansion is moreover bounded by the local search context to better discard irrelevant documents. The experimental evaluation carried out on the CLIREC dataset shows the benefit of our approaches.