349 research outputs found

    Quantitative two-dimensional shadowgraphic set-up for high-sensitivity measurement of low-density laser-plasmas

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    We present a quantitative shadowgraphic method which can measure the density of a laser-generated plasma in air with sensitivity and resolution comparable or better than traditional interferometric techniques. Simultaneous comparison of both shadowgraphy and interferometry has been carried out allowing the experimental evaluation of the reliability of the shadowgraphic method

    Πρακτικές Διοίκησης Ανθρώπινου Δυναμικού και η συμβολή τους στην ανάπτυξη μιας επιχείρησης.

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    Η σύγχρονη παγκοσμιοποιημένη κοινωνία, η κοινωνία της πληροφορίας και της γνώσης που οφείλει να στηρίζεται και στις αρχές της κοινωνικής ευθύνης, απαιτεί την αλλαγή των κλασσικών παραδοσιακών μοντέλων διοίκησης σε νέα πιο σύγχρονα και πιο ευέλικτα. Πλέον κυριαρχεί η αντίληψη για εξέλιξη πρόοδο και ικανοποίηση του προσωπικού έναντι των οικονομικών αποδόσεων η οποία κερδίζει έδαφος. Επίσης αξίες όπως η ικανοποίηση των υπαλλήλων, οι δυνατότητες ευκαιριών απασχόλησης η αξιοποίηση των δυνατοτήτων των τοπικών κοινωνιών καθώς και η προστασία του περιβάλλοντος αποτελούν προτεραιότητες έναντι της αύξησης των κερδών. Τα μοντέλα αυτά συμβάλουν στην διαμόρφωση μίας νέας αντίληψης, στην διαμόρφωση της διαχείρισης των ανθρώπινων πόρων. Αυτό συνεπάγεται με την ανάπτυξη μίας σειράς συστημάτων που θα έχουν να κάνουν με τον προγραμματισμό, στην άμεση παρακολούθηση και στην αντικειμενική αξιολόγησης της απόδοσης του ανθρώπινου δυναμικού αλλά και στην επικείμενη ανάπτυξη του. Το ανταγωνιστικό πλεονέκτημα του ανθρώπινου δυναμικού μπορεί να ενισχύσει σημαντικά τις δυνατότητες μίας επιχείρησης δημιουργώντας γι αυτήν αξία. Η διοίκηση του ανθρώπινου δυναμικού είναι ο τομέας που ασχολείται με το ανθρώπινο δυναμικό μιας επιχείρησης. Η διοίκηση ανθρώπινων πόρων έχει ως αποστολή της την καλύτερη αξιοποίηση του ανθρώπινου παράγοντα με σκοπό επιχειρήσεις και οργανισμοί να μπορέσουν να πετύχουν τους στρατηγικούς στόχους τους. Μέσω λοιπόν αυτής της διπλωματικής θα ασχοληθώ με τον προγραμματισμό, την διαδικασία πρόσληψης την κατάρτιση την αξιολόγηση του προσωπικού σε μια επιχείρηση, τα συστήματα αμοιβής και τα κίνητρα που πρέπει να δύνονται στους εργαζόμενους, την αξιολόγηση τους, την εσωτερική επικοινωνία στην επιχείρηση, την κουλτούρα και πως διαμορφώνεται σε μια εταιρεία, εξετάζονται τα εργαλεία στρατηγικού σχεδιασμού και απόδοσης S.W.O.T & Balanced Scorecard, γίνεται αναφορά στα πληροφοριακά συστήματα που χρησιμοποιούν στα τμήματα HR και τέλος γίνεται μια προσπάθεια δημιουργίας S.W.O.T analysis και Balanced Scorecard για την εταιρεία Tesla.The modern globalized society, the information and knowledge society that must also be based on the principles of social responsibility, demands the change of classic traditional models of administration to more modern and more flexible ones. Nowadays, the perception of progress and satisfaction of the financial performance of the staff is gaining ground. Also values such as employee satisfaction, employment opportunities, exploiting the potential of local communities and protecting the environment are priorities against financial returns. These models help shape a new understanding of human resource management. This implies the development of a number of systems related to planning, direct monitoring and objective evaluation of the performance of the human resources and their forthcoming development. The competitive advantage of human resources can greatly enhance the capabilities of a business by creating value for it. Human resource management is the area that deals with the human resources of a business. The mission of human resources management is to make the best use of the human factor in order for businesses and organizations to achieve their strategic goals. Τhrough this thesis I will be involved in the planning, the recruitment process, the training of the staff in a business, the pay systems and incentives that need to be put into the employees, their evaluation, the internal communication in the business, the culture and how it is shaped into a company, there will be reference about the strategic planning and performance tools of S.W.O.T & Balanced Scorecard analysis, also the information systems used in HR departments, and finally an attempt to create S.W.O.T analysis and Balanced Scorecard for Tesla Inc

    Time-resolved refractive index and absorption mapping of light-plasma filaments in water

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    By means of a quantitative shadowgraphic method, we performed a space-time characterization of the refractive index variation and transient absorption induced by a light-plasma filament generated by a 100 fs laser pulse in water. The formation and evolution of the plasma channel in the proximity of the nonlinear focus were observed with a 23 fs time resolution.Comment: 3 pages, 3 picture

    The Significance of the Lingual Nerve During Periodontal/Implant Surgery

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141105/1/jper0372.pd

    Tissue Biotype and Its Relation to the Underlying Bone Morphology

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142069/1/jper0569.pd

    Clinical, microbiological, and salivary biomarker profiles of dental implant patients with type 2 diabetes

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    Objective Regulators of peri‐implant bone loss in patients with diabetes appear to involve multiple risk factors that have not been clearly elucidated. This study was conducted to explore putative local etiologic factors on implant bone loss in relation to type 2 diabetes mellitus, including clinical, microbial, salivary biomarker, and psychosocial factors. Materials and methods Thirty‐two subjects (divided into type 2 diabetes mellitus and non‐diabetic controls), having at least one functional implant and six teeth, were enrolled in a 1‐year longitudinal investigation. Analyses of clinical measurements and standardized intra‐oral radiographs, saliva and serum biomarkers (via protein arrays for 20 selected markers), and plaque biofilm (via q PCR for eight periodontal pathogens) were performed at baseline and 1 year. In addition, the subjects were asked to respond to questionnaires to assess behavioral and psychosocial variables. Results There was a significant increase from baseline to 1 year in the probing depth of implants in the diabetes group (1.95 mm to 2.35 mm, P  = 0.015). The average radiographic bone loss during the study period marginally increased at dental implants compared to natural teeth over the study period (0.08 mm vs. 0.05 mm; P  = 0.043). The control group harbored higher levels of T reponema denticola at their teeth at baseline ( P  = 0.046), and the levels of the pathogen increased significantly over time around the implants of the same group ( P  = 0.003). Salivary osteoprotegerin ( OPG ) levels were higher in the diabetes group than the control group at baseline only; in addition, the salivary levels of IL ‐4, IL ‐10, and OPG associated with host defense were significantly reduced in the diabetes group ( P  = 0.010, P  = 0.019, and P  = 0.024), while controls showed an increase in the salivary OPG levels ( P  = 0.005). For psychosocial factors, there were not many significant changes over the observation period, except for some findings related to coping behaviors at baseline. Conclusions The study suggests that the clinical, microbiological, salivary biomarker, and psychosocial profiles of dental implant patients with type 2 diabetes who are under good metabolic control and regular maintenance care are very similar to those of non‐diabetic individuals. Future studies are warranted to validate the findings in longer‐term and larger clinical trials ( ClinicalTrials.gov # NCT00933491).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107497/1/clr12139.pd

    Kinetic Theory of Radiation in Nonequilibrium Relativistic Plasmas

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    Many-particle QED is applied to kinetic theory of radiative processes in many- component plasmas with relativistic electrons and nonrelativistic heavy particles. Within the framework of nonequilibrium Green's function technique, transport and mass-shell equations for fluctuations of the electromagnetic field are obtained. We show that the transverse field correlation functions can be decomposed into sharply peaked (non-Lorentzian) parts that describe resonant (propagating) photons and off-shell parts corresponding to virtual photons in plasmas. Analogous decomposi- tions are found for the longitudinal field correlation functions and the correlation functions of relativistic electrons. As a novel result a kinetic equation for the reso- nant photons with a finite spectral width is derived. The off-shell parts of the particle and field correlation functions are shown to be essential to calculate the local ra- diating power in relativistic plasmas and recover the results of vacuum QED. The influence of plasma effects and collisional broadening of the relativistic quasiparticle spectral function on radiative processes is discussed.Comment: 63 pages, 11 figure

    Electromagnetic energy penetration in the self-induced transparency regime of relativistic laser-plasma interactions

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    Two scenarios for the penetration of relativistically intense laser radiation into an overdense plasma, accessible by self-induced transparency, are presented. For supercritical densities less than 1.5 times the critical one, penetration of laser energy occurs by soliton-like structures moving into the plasma. At higher background densities laser light penetrates over a finite length only, that increases with the incident intensity. In this regime plasma-field structures represent alternating electron layers separated by about half a wavelength by depleted regions.Comment: 9 pages, 4 figures, submitted for publication to PR

    Repeated delivery of chlorhexidine chips for the treatment of periimplantitis: A multicenter, randomized, comparative clinical trial.

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    "This is the peer reviewed version of the following article:Machtei, EE, Romanos, G, Kang, P, et al. Repeated delivery of chlorhexidine chips for the treatment of periimplantitis: A multicenter, randomized, comparative clinical trial. J Periodontol. 2020; 1– 10. https://doi.org/10.1002/JPER.20-0353 which has been published in final form at doi: https://doi.org/10.1002/JPER.20-0353 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."BACKGROUND: Periimplantitis is a challenging condition to manage and is frequently treated using non-surgical debridement. The local delivery of antimicrobial agents has demonstrated benefit in mild to moderate cases of periimplantitis. This study compared the safety and efficacy of Chlorhexidine gluconate 2.5 mg chip (CHX chips) as an adjunctive treatment to sub-gingival debridement in patients afflicted with periimplantitis. METHODS: A multi-center, randomized, single-blind, two-arm, parallel Phase-3 study was conducted. Periimplantitis patients with implant pocket depths (IPD) of 5-8 mm underwent sub-gingival implant surface debridement followed by repeated bi-weekly supra-gingival plaque removal and Chlorhexidine chips application (ChxC group) for 12 weeks, or similar therapy but without application of ChxC (control group). All patients were followed for 24 weeks. Plaque and gingival indices were measured at every visit while IPD, recession and bleeding on probing were assessed at 8,12,16,24 week. RESULTS: 290 patients were included: 146 in the ChxC group and 144 in the control. At 24 weeks, a significant reduction in IPD (p = 0.01) was measured in the ChxC group (1.76 ± 1.13 mm) compared to the control group (1.54 ± 1.13 mm). IPD reduction of ≥2 mm was found in 59% and 47.2% of the implants in the ChxC and control groups, respectively (p = 0.03). Changes in gingival recession (0.29 ± 0.68 mm vs. 0.15 ± 0.55 mm, p = 0.015) and relative attachment gain (1.47 ± 1.32 mm and 1.39 ± 1.27 mm, p = 0.0017) were significantly larger in the ChxC group. Patients in the ChxC group that were <65 years exhibited significantly better responses (p<0.02); likewise, non-smokers had similarly better response (p <0.02). Both protocols were well tolerated, and no severe treatment-related adverse events were recorded throughout the study. CONCLUSIONS: Patients with periimplantitis that were treated with an intensive treatment protocol of bi-weekly supra-gingival plaque removal and local application of Chlorhexidine chips had greater mean IPD reduction and greater percentile of sites with IPD reduction of ≥2 mm. as compared to bi-weekly supra-gingival plaque removal. (Clinicaltrials.gov NCT02080403). This article is protected by copyright. All rights reserved

    A microRNA negative feedback loop downregulates vesicle transport and inhibits fear memory

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    The SNARE-mediated vesicular transport pathway plays major roles in synaptic remodeling associated with formation of long-term memories, but the mechanisms that regulate this pathway during memory acquisition are not fully understood. Here we identify miRNAs that are up-regulated in the rodent hippocampus upon contextual fear-conditioning and identify the vesicular transport and synaptogenesis pathways as the major targets of the fear-induced miRNAs. We demonstrate that miR-153, a member of this group, inhibits the expression of key components of the vesicular transport machinery, and down-regulates Glutamate receptor A1 trafficking and neurotransmitter release. MiR-153 expression is specifically induced during LTP induction in hippocampal slices and its knockdown in the hippocampus of adult mice results in enhanced fear memory. Our results suggest that miR-153, and possibly other fear-induced miRNAs, act as components of a negative feedback loop that blocks neuronal hyperactivity at least partly through the inhibition of the vesicular transport pathway.Brain & Behavior Research Foundation (Young Investigator Award)JPB Foundatio
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