Towards a sustainable open educational resources development model : tapping into the cognitive surplus of student-generated content

Open Educational Resources (OER) have created opportunities for learners around the world. Previous research investigated different OER development models for higher educational institutions and other educational communities. However, maintaining sustainability remains the main challenge of OER projects, as there is a high demand on raising awareness of the value of OER in higher education, as well as the need for expanding a participation base in the OER development process and improving the quality of OER. As a response to these challenges, the research documented in this thesis presents a new OER development model that establishes communities of practices around OER in higher educational institutions, where the knowledge production that takes place inside classrooms provides sustainable resources for the OER development process. OER literature also shows initiatives on engaging students in the OER development process, however, there is a lack of rigor research that shows the principles of engaging students in this process. Hence, this study is focused on identifying the design principles of the sustainable OER development model that engages students in generating OER. The model was designed to establish communities of practice of students and teachers to work collaboratively in generating learning resources. In the context of computing and information technology studies for undergraduate learning environments, students generate a surplus of projects in different study units with some projects repurposed, however, a surplus of projects that are generated on every academic semester are rarely tapped into. This abundance of knowledge production is described as ‘cognitive surplus’ and tapping into it can maximise the value of these projects. Therefore, the proposed OER development model taps into the cognitive surplus of student-generated content, where instead of generating summaries and portfolios, students create learning resources based on the unit topics using content authoring software tools. In this model, teachers work as facilitators and co-creators, providing evaluation of learning resources in order to be published as OER. To engage students in generating learning resources for OER, the learning assessment approach was taken from assessing student projects on reproducing information to a new level where students engaged in structuring, designing, collecting and evaluating content for generating learning resources which was then shared online as OER. These activities maximised students’ responsibilities, because sharing work online motivated them to improve the quality of the learning content. To be able to design a new OER development model, there was a need to understand the characteristics of the learning environment, including students, teachers and the learning material. In addition, developing a pedagogically informed approach to adopt the OER development model in learning environments, which can help with improving students’ learning performance and advance the teaching practices through open educational practices (OEP), was also required.Therefore, to fulfil these requirements, this thesis elaborates on the literature review of the related areas of the OER development model and provides analysis of the emerging concepts and related theories. The thesis also presents and reflects on the stages of model development, refinements and evaluation over the lifetime of the study, and provides practical evidence on the potential sustainability of the model in real-life learning environments

Redo aortic valve replacement after partial upper sternotomy (hemisternotomy) in a patient with idiopathic thrombocytopenia: a case report

BACKGROUND: We present a case of redo aortic valve replacement in a patient with thrombocytopenia. The initial operation was performed through limited access transverse sternotomy. This is the first report of this kind in the literature. CASE PRESENTATION: A 62 year old Caucasian male farmer with thrombocytopenia had uneventful redo aortic valve replacement when the first xenograft failed after 9 years, the transverse upper hemisternotomy in the first operation appearing to facilitate the redo complete sternotomy. CONCLUSION: With this only case of redo aortic valve replacement in our practice of 90 hemisternotomies over 10 years we present for consideration the use of a tissue valve in a complex relatively young patient

L'accoppiamento ventricolo-arterioso nel paziente iperteso

RIASSUNTO Come noto, le alterazioni strutturali e funzionali a livello arterioso legate all’età sono rappresentate da ispessimento medio-intimale, da modificazioni della stiffness parietale, da disfunzione endoteliale; questi contribuiscono ad un progressivo aumento dell’elastanza arteriosa a riposo. In corrispondenza, a livello cardiaco le alterazioni legate al rimodellamento ventricolare (processi di ipertrofia dei miociti e aumentato turn-over del collageno a livello della matrice extracellulare) provocano una progressiva disfunzione sisto-diastolica del ventricolo sinistro (che può arrivare fino alla fase dello scompenso cardiaco conclamato) e ad un conseguente incremento dell’elastanza cardiaca. Le alterazioni cardio-vascolari sia strutturali che funzionali legate all’età risultano essere accelerate in presenza dei diversi fattori di rischio, ad esempio di ipertensione arteriosa. Scopo: il presente lavoro ha avuto lo scopo di indagare la correlazione tra elastanza ventricolare ed arteriosa in una popolazione di soggetti con ipertensione arteriosa e se esistano variazioni legate all’età dei parametri esaminati di valutazione di rigidità aortica e carotidea in relazione agli indici di rimodellamento strutturale e funzionale del ventricolo sinistro. Popolazione e Metodi:Sono stati studiati complessivamente 65 pazienti ipertesi essenziali di cui 40 uomini e 25 femmine, afferenti agli ambulatori del Centro Regionale dell’ Ipertensione della U.O. di Medicina Generale I Universitaria. Ciascun paziente ha eseguito un'anamnesi, una valutazione clinica ambulatoriale ed una serie di esami utili per la stratificazione del rischio cardiovascolare, tra cui un elettrocardiogramma,ed esami emato-chimici di routine (creatinina, colesterolo, glicemia). Tutti i pazienti arruolati nello studio sono stati sottoposti ad un esame ecocardiografico trans-toracico, che prevedeva una valutazione standard bidimensionale, monodimensionale e color-Doppler . La valutazione ecocardiografica ha compreso lo studio del rimodellamento ventricolare sinistro e della funzione sisto-diastolica attraversole seguenti misure: volume ediametrie del VS, massa ventricolare sinistra indicizzata per la superficie corporea (LVMI) e per l’altezza (LVM/H), spessore relativo di parete (RWT), FE, rapporto E/A del flusso trans mitralico e studio del Doppler tissutale (TDI) a livello laterale (onda E’ laterale) e mediale (onda E’ mediale) dell’anulus mitralico. Per quanto riguarda lo studio della rigidità arteriosa e’ stata misurata la pulse wave velocity carotido-femorale (cfPWV), tramite la registrazione tonometrica sequenziale delle forma d’onda al sito carotideo e femorale; per far ciò si è adoperato una dispositivo SphygmoCor® (Atcor Medical, Sydney, Australia). Lo studio della rigidità carotidea è stato valutato tramite l’impiego di un apparecchio ecografico ad alta risoluzione; nei pazienti sono state valutate le variazioni sisto-diastoliche di diametro dell'arteria carotide comune, che sono state stimate con un sistema automatico ed è stata fatta la misurazione simultanea dell'IMT sulla stessa sequenza di immagini B-mode (Carotid Studio, Istituto di Fisiologia Clinica, CNR, Pisa, Italia). Risultati: I pazienti dello studio avevano un’età media di 59,9±9,9 anni, con una prevalenza di sesso maschile (che raggiungeva il 62%). Nella popolazione totale l’elastanza ventricolare (ELVI) correlava direttamente in maniera significativa con l’elastanza arteriosa (r=0.708, p<0.0001). Inoltre, nella popolazione con meno di 65 anni , ELVI correleva in maniera significativa con il coefficiente di compliance carotidea (CC) e in maniera non significativa con la velocità dell’onda sfigmica (PWV) , e viceversa nella popolazione con più di 65 anni. Conclusioni: dai risultati ottenuti in questa tesi si è evidenziato come nella popolazione totale esaminata l’elastanza ventricolare correli in maniera significativa e diretta con l’elastanza arteriosa e che i meccanismi di adattamento cardio-vascolare siano diversi in relazione all’et

Secure Communication Using Cryptography and Covert Channel

The keys which are generated by cryptography algorithms have still been compromised by attackers. So, they extra efforts to enhance security, time consumption and communication overheads. Encryption can achieve confidentiality but cannot achieve integrity. Authentication is needed beside encryption technique to achieve integrity. The client can send data indirectly to the server through a covert channel. The covert channel needs pre-shared information between parties before using the channel. The main challenges of covert channel are security of pre-agreement information and detectability. In this chapter, merging between encryption, authentication, and covert channel leads to a new covert channel satisfying integrity and confidentiality of sending data. This channel is used for secure communication that enables parties to agree on keys that are used for future communication

Electronic and structural study of Pt-modified Au vicinal surfaces: a model system for Pt–Au catalysts

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOTwo single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (θPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on θPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings. © 2014 The Owner Societies.Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (yPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on yPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings.Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (yPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on yPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings.16261332913339FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO07/54829-5; 2011/12.566-3; 2012/16860-6160172/2011-0Greeley, J., Stephens, I.E.L., Bondarenko, A.S., Johansson, T.P., Hansen, H.A., Jaramillo, T.F., Rossmeisl, J., Nørskov, J.K., (2009) Nat. Chem., 1, pp. 552-556Wu, G., More, K.L., Johnston, C.M., Zelenay, P., (2011) Science, 332, pp. 443-447Chu, Y.H., Shul, Y.G., (2010) Int. J. Hydrogen Energy, 35, pp. 11261-11270Kowal, A., Li, M., Shao, M., Sasaki, K., Vukmirovic, M.B., Zhang, J., Marinkovic, N.S., Adzic, R.R., (2009) Nat. Mater., 8, pp. 325-330Xu, C.W., Su, Y.Z., Tan, L.L., Liu, Z.L., Zhang, J.H., Chen, S.A., Jiang, S.P., (2009) Electrochim. Acta, 54, pp. 6322-6326Colmati, F., Antolini, E., Gonzalez, E.R., (2008) J. Alloys Compd., 456, pp. 264-270Antolini, E., (2007) J. Power Sources, 170, pp. 1-12Colmati, F., Antolini, E., Gonzalez, E.R., (2006) J. Power Sources, 157, pp. 98-103Stamenkovic, V.R., Mun, B.S., Mayrhofer, K.J.J., Ross, P.N., Markovic, N.M., (2006) J. Am. Chem. Soc., 128, pp. 8813-8819Freund, H.-J., Pacchioni, G., (2008) Chem. Soc. Rev., 37, pp. 2224-2242Kim, Y., Kim, H.J., Kim, Y.S., Choi, S.M., Seo, M.H., Kim, W.B., (2012) J. Phys. Chem. C, 116, pp. 18093-18100Kwon, Y., Birdja, Y., Spanos, I., Rodriguez, P., Koper, M.T.M., (2012) ACS Catal., 2, pp. 759-764Freitas, R.G., Pereira, E.C., (2010) Electrochim. Acta, 55, pp. 7622-7627Colmati, F., Tremiliosi, G., Gonzalez, E.R., Berna, A., Herrero, E., Feliu, J.M., (2009) Phys. Chem. Chem. Phys., 11, pp. 9114-9123Repain, V., Baudot, G., Ellmer, H., Rousset, S., (2002) Europhys. Lett., 58, p. 730Repain, V., Berroir, J.M., Rousset, S., Lecoeur, J., (1999) Europhys. Lett., 47, p. 435Nahas, Y., Repain, V., Chacon, C., Girard, Y., Rousset, S., (2010) Surf. Sci., 604, pp. 829-833Rohart, S., Girard, Y., Nahas, Y., Repain, V., Rodary, G., Tejeda, A., Rousset, S., (2008) Surf. Sci., 602, pp. 28-36Rohart, S., Baudot, G., Repain, V., Girard, Y., Rousset, S., Bulou, H., Goyhenex, C., Proville, L., (2004) Surf. Sci., 559, pp. 47-62Axel, G., (2009) J. Phys.: Condens. Matter, 21, p. 084205Rodriguez, J., (1996) Surf. Sci. Rep., 24, pp. 223-287Eyrich, M., Diemant, T., Hartmann, H., Bansmann, J., Behm, R.J., (2012) J. Phys. Chem. C, 116, pp. 11154-11165Bowker, M., (1995) Chem. Vap. Deposition, 1, p. 90Xu, J.B., Zhao, T.S., Yang, W.W., Shen, S.Y., (2010) Int. J. Hydrogen Energy, 35, pp. 8699-8706Wang, J., Yin, G., Wang, G., Wang, Z., Gao, Y., (2008) Electrochem. Commun., 10, pp. 831-834Horcas, I., Fernandez, R., Gomez-Rodriguez, J.M., Colchero, J., Gomez-Herrero, J., Baro, A.M., (2007) Rev. Sci. Instrum., 78, pp. 013705-013708Doniach, S., Sunjic, M., (1970) J. Phys. C: Solid State Phys., 3, p. 285Hörnström, S.E., Johansson, L., Flodström, A., Nyholm, R., Schmidt-May, J., (1985) Surf. Sci., 160, pp. 561-570Shevchik, N.J., (1974) Phys. Rev. Lett., 33, p. 1336Powell, C.J., (2012) J. Electron Spectrosc. Relat. Phenom., 185, pp. 1-3Rousset, S., Repain, V., Baudot, G., Garreau, Y., Lecoeur, J., (2003) J. Phys.: Condens. Matter, 15, p. 3363Prévot, G., Girard, Y., Repain, V., Rousset, S., Coati, A., Garreau, Y., Paul, J., Narasimhan, S., (2010) Phys. Rev. B: Condens. Matter Mater. Phys., 81, p. 075415Repain, V., Rohart, S., Girard, Y., Tejeda, A., Rousset, S., (2006) J. Phys.: Condens. Matter, 18, p. 17Repain, V., Baudot, G., Ellmer, H., Rousset, S., (2002) Mater. Sci. Eng., B, 96, pp. 178-187Repain, V., Berroir, J.M., Rousset, S., Lecoeur, J., (2000) Surf. Sci., 447, pp. 152-L156Campiglio, P., Repain, V., Chacon, C., Fruchart, O., Lagoute, J., Girard, Y., Rousset, S., (2011) Surf. Sci., 605, pp. 1165-1169Prieto, M.J., Carbonio, E.A., Landers, R., De Siervo, A., (2013) Surf. Sci., 617, pp. 87-93Antczak, G., Ehrlich, G., (2010) Surface Diffusion: Metals, Metal Atoms, and Clusters, , Cambridge Univesrity Press, New YorkKim, S.Y., Lee, I.-H., Jun, S., (2007) Phys. Rev. B: Condens. Matter Mater. Phys., 76, p. 245407Liu, Y.B., Sun, D.Y., Gong, X.G., (2002) Surf. Sci., 498, pp. 337-342Prévot, G., Barbier, L., Steadman, P., (2010) Surf. Sci., 604, pp. 1265-1272Pedersen M.Ø, Helveg, S., Ruban, A., Stensgaard, I., Lægsgaard, E., Nørskov, J.K., Besenbacher, F., (1999) Surf. Sci., 426, pp. 395-409Gohda, Y., Groß, A., (2007) Surf. Sci., 601, pp. 3702-3706Pastor, E., Rodriguez, J.L., Iwasita, T., (2002) Electrochem. Commun., 4, pp. 959-962Keister, J.K., Rowe, J.E., Kolodziej, J.J., Madey, T.E., (2000) J. Vac. Sci. Tech. B, 18, pp. 2174-2178. , 10.1116/1.1305872Martin, R., Gardner, P., Bradshaw, A.M., (1995) Surf. Sci., 342, pp. 69-84Bare, S.R., Hofmann, P., King, D.A., (1984) Surf. Sci., 144, pp. 347-369Yamagishi, S., Fujimoto, T., Inada, Y., Orita, H., (2005) J. Phys. Chem. B, 109, pp. 8899-8908Watanabe, S., Inukai, J., Ito, M., (1993) Surf. Sci., 293, pp. 1-9Sarkar, A., Kerr, J.B., Cairns, E.J., (2013) ChemPhysChem, 14, pp. 2132-2142Du, B., Zaluzhna, O., Tong, Y.J., (2011) Phys. Chem. Chem. Phys., 13, pp. 11568-11574Auten, B.J., Lang, H., Chandler, B.D., (2008) Appl. Catal., B, 81, pp. 225-235Gohda, Y., Groß, A., (2007) J. Electroanal. Chem., 607, pp. 47-53Kobiela, T., Moors, M., Linhart, W., Cebula, I., Krupski, A., Becker, C., Wandelt, K., (2010) Thin Solid Films, 518, pp. 3650-3657Petkov, V., Wanjala, B.N., Loukrakpam, R., Luo, J., Yang, L., Zhong, C.-J., Shastri, S., (2012) Nano Lett., 12, pp. 4289-4299Authors thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP-07/54829-5) and Conselho Nacional de Pesquisa (CNPq) for financial support. Specially thank to L. H. Lima for experimental assistance with STM measurements and Prof. G. Tremiliosi-Filho for lending the Au(332) crystal. MJP, SF and EAC thank FAPESP and CNPq for the fellowships granted (Procs. FAPESP 2011/12.566-3 and 2012/16860-6; Proc. CNPq 160172/2011-0)

Intramolecular coupling of terminal alkynes by atom manipulation

Glaser-like coupling of terminal alkynes by thermal activation is extensively used in on-surface chemistry. Here we demonstrate an intramolecular version of this reaction performed by atom manipulation. We used voltage pulses from the tip to trigger a Glaser-like coupling between terminal alkyne carbons within a custom synthesized precursor molecule adsorbed on bilayer NaCl on Cu(111). Different conformations of the precursor molecule and the product were characterized by molecular structure elucidation with atomic force microscopy and orbital density mapping with scanning tunneling microscopy, accompanied by density functional theory calculations. We revealed partially dehydrogenated intermediates providing insight into the reaction pathway

Self-assembly Of Nitpp On Cu(111): A Transition From Disordered 1d Wires To 2d Chiral Domains.

The growth and self-assembling properties of nickel-tetraphenyl porphyrins (NiTPP) on the Cu(111) surface are analysed via scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). For low coverage, STM results show that NiTPP molecules diffuse on the terrace until they reach the step edge of the copper surface forming a 1D system with disordered orientation along the step edges. The nucleation process into a 2D superstructure was observed to occur via the interaction of molecules attached to the already nucleated 1D structure, reorienting molecules. For monolayer range coverage a 2D nearly squared self-assembled array with the emergence of chiral domains was observed. The XPS results of the Ni 2p(3/2) core levels exhibit a 2.6 eV chemical shift between the mono- and multilayer configuration of NiTPP. DFT calculations show that the observed chemical shifts of Ni 2p(3/2) occur due to the interaction of 3d orbitals of Ni with the Cu(111) substrate.1718344-1835