880 research outputs found
Two birds with one stone: The use of screen-time multitasking and its effect on attention and comprehension scores in college students
In today’s world, the use of media outlets has become an essential facet of daily life. One of the largest forms of media is distributed through the television streaming company Netflix. Netflix has become the world’s central line for screen-time entertainment, with over 62 million subscribers utilizing its streaming services (Mander, 2015). The present study asked whether screen-time multitasking affects attention and retention abilities in academic performance. In order to examine the main effect of media multitasking, I conducted a randomly assigned, single blind between groups study that manipulated the use of media multitasking and comprehension testing. An experimental group of undergraduate students (N=10) were told to complete a reading passage and follow-up comprehension questions while having a comedic five minute segment of “The Office” play in the background. The control group of undergraduate students (N=10) read the passage and took the comprehension test in a silent setting, without media influence. The results indicated that the experimental group required significantly longer times to complete the reading and comprehension questions (p\u3c.013) In addition, the group exposed to media multitasking scored significantly lower on the comprehension questions (p\u3c.035) and reported lower levels of confidence in relation to overall comprehension of the reading passage (p\u3c.04)
a histological study in dogs
0 Deckblatt und Inhaltsverzeichnis
1 Einleitung
1
2 LiteraturĂĽbersicht
2
3 Ziel der Untersuchung
41
4 Material und Methode
42
5 Ergebnisse
56
6 Diskussion
66
7 Schlussfolgerungen
81
8 Zusammenfassung
82
9 Summary
83
10 Literaturverzeichnis
84
11 Anhang
94
12 Danksagung
97
13 Lebenslauf
98
14 Erklärung an Eides statt
99In seltenen Fällen entstehen Zahnperforationen durch resorptive oder kariöse
Prozesse. Mit Abstand am häufigsten treten sie jedoch während der
Wurzelkanalbehandlung oder postendodontisch im Zuge der Stiftpräparation auf
und stellen dabei eine wichtige Ursache fĂĽr Misserfolge von
Wurzelkanalbehandlungen dar. Das Ziel der vorliegenden Studie war, die
EntzĂĽndungsgrade und Gewebereaktionen gegenĂĽber einem experimentellen
Trikalziumphosphatzement (TCP) und Mineralischem Trioxidaggregat (MTA) als
Materialien fĂĽr furkale Perforationsversorgungen an Hunden histologisch zu
untersuchen. Hierzu wurden Perforationen an 24 Unterkieferprämolaren von sechs
narkotisierten Hunden präpariert und entweder mit ProRoot MTA (grau) oder TCP
gefüllt. Anschließend erfolgten Aufbereitung und Füllung der Wurzelkanäle
sowie der adhäsive Verschluss der Trepanationsöffnung mit einem chemisch
härtenden Komposit. Zwölf Wochen später wurden die Tiere geopfert. Im
Anschluss an die Röntgendiagnostik konnten die behandelten Zähne und das
umliegende Gewebe mit Hilfe der Trenn-DĂĽnnschliff-Technik nach
Methylmethakrylat-Einbettung fĂĽr die lichtmikroskopische Untersuchung
vorbereitet werden. Hinsichtlich des EntzĂĽndungsgrades zeigte das MTA
signifikant bessere Ergebnisse als der TCP (p = 0,004; Chi-Quadrat-Test nach
Pearson). Keine Furkation war frei von EntzĂĽndungszellen. Milde
Entzündungsgrade konnten bei neun von zwölf mit MTA und lediglich bei zwei mit
TCP gefĂĽllten Perforationen beobachtet werden. Keine signifikanten
Unterschiede zwischen MTA und dem TCP wurden bezĂĽglich Knochenumbau (p =
0,304; Mantel-Haenszel-Chi-Quadrat-Test) und Fibroplasie (p = 0,744)
ermittelt. Angesichts der ĂĽberwiegend milden Gewebereaktionen scheinen beide
Zemente für die Behandlung von Perforationen geeignet und den herkömmlichen
Materialien ĂĽberlegen zu sein. Dennoch stellen Perforationen, insbesondere in
der Furkation, nach wie vor ein sowohl endodontisches als auch
parodontologisches Problem mit unsicherer Prognose dar.In some cases, root perforations can result from resorptions and carious
lesions. However, this incident usually occurs during endodontic treatment and
preparations for a post and represents an important reason for endodontic
failure. The purpose of this study was to evaluate histologically the
inflammatory reactions and tissue responses to an experimental tricalcium
phosphate cement (TCP) and mineral trioxide aggregate (MTA) when used as
repair materials in furcation perforations in dogs. Perforations were
performed in 24 mandibular premolars of six anaesthetized dogs and filled
either with ProRoot MTA (grey) or TCP. The root canals were subsequently
shaped and filled, and the access cavities closed with a bonded chemical cured
composite resin. The animals were sacrificed at 12 weeks. After radiological
examination, the treated teeth and surrounding structures were processed for
light microscopy using the cutting-grinding technique with methyl methacrylate
embedding. Concerning grade of inflammation, MTA exhibited significantly
better results than TCP (p = 0.004; Chi square test according to Pearson). No
furcation was free from inflammatory cells. Mild inflammation was observed in
nine of twelve cases with MTA and only twice in those with TCP. No significant
differences were revealed between MTA and TCP in terms of bone reorganization
(p = 0.304; Mantel-Haenszel-Chi square test) or deposition of fibrous
connective tissue (p = 0.744). Considering the predominantly mild tissue
reactions observed, both cements seem to be suitable for perforation repair
and superior in comparison with traditional materials. Nevertheless,
perforations located in the furcation of teeth remain an endodontic and a
periodontal problem with an uncertain prognosis, in spite of the promising
modern materials applied
Shear Strength of Carbon Fiber/Epoxy Hinges Using the V-Notch Rail Shear Test
The mechanical properties of carbon fiber reinforced polymer (CFRP) hinges produced by Common Fibers (Kent, Washington) are a new technology with uncharacterized mechanical properties. Currently, Common Fiber’s hinges are utilized in wallets, but in order to expand the application of the hinges to structural components, complete characterization of the mechanical properties of the hinges is necessary. To address this problem, hinges developed by Common Fibers were tested utilizing the V-Notch rail shear test, ASTM D7078, to determine the shear strength of the hinges. Two layups, [+45/-45/0]s and [0/+45/-45/0]s were produced by Common Fibers for the experiment. Hinged and unhinged laminates of both layups were tested using the V-Notch rail shear test for maximum load producing load-extension curves. The results of the hinged and unhinged laminates were compared to characterize the shear behavior of the composite hinges. Comparison of hinged and unhinged composites revealed that the production of the hinge results in a reduction in shear strength from an average of 12.260 kN to as low as 1.568 kN. The load-extension curves display a pre-loading phase where the fibers in the hinge region undergo a period of relaxed extension until they are engaged in supporting the applied load. Observations of specimens after testing revealed splintering delamination as the failure mode along the interface between hinged and unhinged material parallel to the 450 oriented fibers
Balancing Efficiency and the Public Interest: A Comparative Analysis of Force Majeure Defaults in Government Contracting
Exemplified by the COVID-19 pandemic, contractual force majeure provisions can serve to protect contracting parties but can also place the risk of nonperformance on parties if the specific elements of the provision cannot be met. The current federal regulations governing government procurement in the United States lack the proper blend of uniformity and flexibility necessary to promote efficient contracting and risk assessment for both federal contractors and government agencies. Specifically, the current force majeure-like provision within the Federal Acquisition Regulation—the excusable delay provision—struggles to perfect this balance and puts government contractors in an unstable position of risk and decreased bargaining. This note examines the current US Federal Acquisition Regulation and its force majeure provision, compares the US provision with that of Canada’s federal regulatory framework, and suggests an adoption of the Canadian provision’s language to make for a more efficient and balanced US provision. More specifically, this note argues that a modified version of the US force majeure provision will continue to insulate the federal government from the risks that could adversely affect not only the national economy but also the public welfare and local economies, while also placing contractors in a less hostile and more efficient contracting environment
Local norms and innovations within the system of locative prepositions in Cajun French
Cajun French presents variable use of linguistic features, as any other variety of French does. Many Cajun French features are considered as deviant from the French norm or triggered by attrition although fluent speakers of Cajun French have always used them. In this sociolinguistic study, we analyze the use of locative prepositions. We add two important dimensions to existing studies: real-time evidence for a diachronic descriptive perspective, and a methodological tool, measuring the degree of exposure to French (MDI). This approach allows us to establish the local prepositional norm of Cajun French and phenomena due to attrition. Large amounts of data for the study of eight categories of locative prepositions are taken from the Cajun French corpus constructed by Dubois in 1997, and also a few interviews conducted by Gold, Louder and Waddell in 1975 are integrated. Our first goal is to determine the overall distribution of prepositions in Cajun French. We discuss their usage in different varieties of French. We show which prepositions are part of the local prepositional norm and which ones are infrequent, sporadic usages that belong to the innovative norm in Cajun French. As a second goal, we present the complex linguistic conditioning system for prepositions in Cajun French, which the fluent and almost all restricted speakers respect. The third goal is to study the effects of the social conditioning. We demonstrate that the local norms are well maintained usages, while the innovative ones are due to language change. We found that some innovations originate in the combined effect of linguistic attrition and change over time, while others have been introduced early as localized usages. Although the young generation shows the highest usage of these forms, they are not responsible for their introduction, but adopt them. Using systemic and extralinguistic criteria, we determined the direct interference from English and internal motivation as sources of the innovations. While diatopic variation overall is weak, Avoyelles parish shows a higher retention of a few long-standing usages than St. Landry and Lafourche, the two other regions under study
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