13,658 research outputs found
MA-Ramirez/Travelers_Dilemma_Code: Zenodo Registration (v1.0.0)
No full textZenodo Registration
This version contains the code base for the published paper in Scientific Reports
Ramírez, M.A., Smerlak, M., Traulsen, A. & Jost. J. (2023). Diversity enables the jump towards cooperation for the Traveler's Dilemm
Testicular atrophy and fibrosis experimentally induced by intratesticular injection of propylenglycol [ATROFIA Y FIBROSIS TESTICULAR EXPERIMENTALMENTE INDUCIDA POR INYECCION INTRATESTICULAR DE PROPILENGLICOL]
No full text[No abstract available
Testicular atrophy and fibrosis experimentally induced by intratesticular injection of propylenglycol [ATROFIA Y FIBROSIS TESTICULAR EXPERIMENTALMENTE INDUCIDA POR INYECCION INTRATESTICULAR DE PROPILENGLICOL]
No full text[No abstract available
Deep anisotropic dry etching of silicon microstructures by high-density plasmas
No full textThis thesis deals with the dry etching of deep anisotropic microstructures in monocrystalline silicon by high-density plasmas. High aspect ratio trenches are necessary in the fabrication of sensitive inertial devices such as accellerometers and gyroscopes. The etching of silicon in fluorine-based plasmas is isotropic. To obtain anisotropy the addition of sidewall passivation is necessary. This is achieved with both oxygen passivation at low temperatures and fluorocarbon passivation at room temperature. A quantitative approach was pursued to explain the etching mechanism. The etch results were analysed using the measured plasma species fluxes and the surface composition. Moreover, the transport of the plasma species in narrow anisotropic structures is a fundamental factor determining the etch rate and the profile evolution. The experimental methods such as the etching equipment, plasma diagnostics, surface analysis and sample preparation are described in chapter 2. Three etching processes were investigated: the cryogenic etching process with oxygen passivation at low temperatures, the Bosch process with fluorocarbon passivation at room temperature and the novel triple pulse process that was developed in our laboratory. The polymer deposition mechanism and the characteristic role of the ions are also explained. The cryogenic etching process is discussed in chapter 3. Fluorine radicals, oxygen radicals and ion bombardment are responsible for the three main sub-processes, that is, etching, sidewall passivation and depassivation of the trench bottom, respectively. Etching experiments with an extremely low ion-to-radical flux ratio were used to reveal the etching mechanism. Crystal orientation dependent etching leading to Si(111) crystal facets is observed in a surface kinetics controlled regime. By varying the plasma conditions it is possible to adjust the etching mechanism from fluorine-limited to ion-limited. Controlled etching is obtained because the etching is tuned from aspect ratio dependent in the fluorine-limited domain to aspect ratio independent in the ion-limited domain. The transport of radicals in high aspect ratio trenches is an important limiting factor and was investigated with special structures. The etch results are described by an analytic model that is based on the surface site balance of fluorine and oxygen radicals. The results are further explained with a Monte Carlo simulation model. The Bosch process is clarified in chapter 4. The anisotropy of the etched structures is controlled by balancing the etching and passivation pulse. However, the maximal obtainable aspect ratio is limited by convergence of the trench sidewalls due to excessive passivation. The maximal obtainable aspect ratio increases if the ion-to-radical flux ratio increases. The transport of ions is an important limiting factor in the depassivation of the bottom of the trench. Divergence of the ion beam leads to a reduction of the ion flux, so that the fluorocarbon passivation is insufficiently removed near the base of the sidewalls. The average ion angle was measured and correlated to the maximal obtainable aspect ratio. The Bosch process was improved at the depassivation side with the triple pulse process and at the passivation side with preferential sidewall deposition. The triple pulse process that is described in chapter 5 has the aim to improve the depassivation in deep trenches. The three main sub-processes are decoupled using a separate depassivation pulse directly after the etching and passivation pulses. The fluorocarbon passivation is efficiently removed with low-pressure, high-density, oxygen-based plasmas. The investigated plasma chemistries include O2, CO2 and SO2. The triple pulse process leads to better profile control with a straight trench bottom. However, the maximal obtainable aspect ratio is comparable to the Bosch process because a larger etch depth and a small lateral etch cancel out. The polymer deposition mechanism is treated in chapter 6 with the aim to understand the fluorocarbon passivation in deep trenches. The deposition on plane surfaces and on special structures was investigated to distinguish between the radical-induced and ion-enhanced components. A simple analytical model, which explains the main deposition characteristics, was developed. Preferential sidewall deposition is obtained for higher ion fluxes and higher bias voltages where sputtering plays an important role. In this case no fluorocarbon passivation has to be removed from the bottom of the trench. The trench profile was optimised in the Bosch process by tuning the bias voltage during etching and passivation independently. It resulted in perfectly anisotropic trenches but the maximal obtainable aspect ratio was still limited by a small lateral etch. The characteristic role of the ions in the etching mechanism is explained in chapter 7. Ion-induced etching of both SiC in a SF6-O2 plasma and Si in a Cl2 plasma were investigated. The impact of the ions on the profile evolution can be examined more explicitly because spontaneous chemical reactions are absent for these plasma-material systems. The etching mechanism varies from fluorine-limited to ion-limited depending on the radical-to-ion flux ratio. Microtrenches are observed for an ion-limited etching mechanism. Fluorine-limited SiC etching is aspect ratio dependent in contrast to ion-limited SiC etching, which is aspect ratio independent. The etching of high aspect ratio SiC structures is limited by the positive sidewall taper. This is presumably caused by insufficient removal of the thin fluorocarbon layer on the surface. Si etching in a Cl2 plasma is always aspect ratio independent in contrast to SiC etching because of the low reaction probability. The conclusions and recommendations of this thesis are given in chapter 8.Applied Science
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Enhancing Uptake and Dissemination of Evidence-based Interventions among U.S. Latino Immigrants: Infusing Cultural Stress into Youth Alcohol Prevention
No full textIn this policy brief, authors Pablo Montero-Zamora, Ph.D., Esmeralda Ramirez, M.A., and Andrea Lopez-Soto, D.D.S., M.S., demonstrate how insights about cultural stress can inform the adaptation of alcohol prevention programs for Latino immigrant families. They report focus group findings on how cultural stress affects willingness to participate, describe key strategies for prevention program implementation, and propose policy recommendations for action.Liberal Art
The blessed Christina from Spoleto: a case of 15th century artificial mummy from Umbria (central italy)
No full textThe study of the artificial mummy of the Blessed Christine (c. 1432-1458) from Spoleto (Umbria, central Italy) showed a young, very obese women, with an anthropological age of 20-25 years and a stature of 1.45 m. The body was eviscerated by a transversal cut at the bottom of the neck, a jugulo-epigastric incision, with longitudinal section of the sternum, and a semicircular incision of the epigastric region. Excerebration was obtained by an ovoidal opening of 6x3.5 cm in the squama of the occipital bone. Finally the body was defleshed by several incisions in the arms and limbs and the body cavities were filled with a sort of padding mixed with powder plants, with no suture. We are in the presence of a very complex embalming method, which witnesses a long-practised and diffused custom
Bridging the DNA divide: Understanding the interplay between replication- gaps and homologous recombination proteins RAD51 and BRCA1/2
No full textA key but often neglected component of genomic instability is the emergence of single-stranded DNA (ssDNA) gaps during DNA replication in the absence of functional homologous recombination (HR) proteins, such as RAD51 and BRCA1/2. Research in prokaryotes has shed light on the dual role of RAD51's bacterial ortholog, RecA, in HR and the protection of replication forks, emphasizing its essential role in preventing the formation of ssDNA gaps, which is vital for cellular viability. This phenomenon was corroborated in eukaryotic cells deficient in HR, where the formation of ssDNA gaps within newly synthesized DNA and their subsequent processing by the MRE11 nuclease were observed. Without functional HR proteins, cells employ alternative ssDNA gap-filling mechanisms to ensure survival, though this compensatory response can compromise genomic stability. A notable example is the involvement of the translesion synthesis (TLS) polymerase POL zeta , along with the repair protein POL theta, in the suppression of replicative ssDNA gaps. Persistent ssDNA gaps may result in replication fork collapse, chromosomal anomalies, and cell death, which contribute to cancer progression and resistance to therapy. Elucidating the processes that avert ssDNA gaps and safeguard replication forks is critical for enhancing cancer treatment approaches by exploiting the vulnerabilities of cancer cells in these pathways
Analysis of ecosystem services provision in the Colombian Amazon using participatory research and mapping techniques
No full textOver the last two decades indigenous peoples in the lower Caquetá River basin in Colombia have experienced detrimental changes in the provision of important ecosystem services in ways that have significant implications for the maintenance of their traditional livelihoods. To assess these changes we conducted eight participatory mapping activities and convened 22 focus group discussions. We focused the analysis on two types of change: (1) changes in the location of ecosystem services provisioning areas and (2) changes in the stock of ecosystem services. The focal ecosystem services include services such as provision of food, raw materials and medicinal resources. Results from the study show that in the past two decades the demand for food and raw materials has intensified and, as a result, locations of provisioning areas and the stocks of ecosystem services have changed. We found anecdotal evidence that these changes correlate well with socio-economic factors such as greater need for income generation, change in livelihood practices and consumption patterns. We discuss the use of participatory mapping techniques in the context of marginalized and data-poor regions. We also show how this kind of information can strengthen existing ecosystem-based management strategies used by indigenous peoples in the Colombian Amazon
Intergranular Cracking In Alloy 690 With Nb, Mo, And Hf Additions: In Situ Sem High Temperature Deformation Study
No full textThe microstructure behavior during high temperature deformation of Ni-base alloys based on alloy 690 modified with Nb, Mo, and Hf additions were studied. Optical and electron microscopy were used to characterize these materials and the results were compared with Calphadbased modeling results. The alloys behavior was studied between 500 and 1000 °C using an in-situ high temperature deformation test. The role of precipitates on the grain boundary morphology and their effect on grain boundary sliding and the mechanism of ductility-dip cracking are discussed. Both, undulated grain boundaries and primary intra-granular precipitates improved the alloy DDC resistance. © 2012 Trans Tech Publications, Switzerland.706-709945950The Minerals, Metals and Materials Society (TMS),NSFArkoosh, M.A., Fiore, N.F., (1972) Metallurgical Transactions, 3, p. 2235Rhines, F.N., Wray, P.J., (1961) Transactions of the ASM, 54, p. 117Haddrill, D.M., Baker, R.G., (1965) British Welding Journal, p. 411Ii Noecker, F.F., Dupont, J.N., (2009) Welding Journal, 88, p. 7Nissley, N.E., Lippold, J.C., (2009) Welding Journal, 88, p. 131Ramirez, A.J., Lippold, J.C., (2004) Mat. Sci. and Eng. A, 380, p. 259Gifkins, R.C., (1994) Materials Characterization, 32, p. 59Langdon, T.G., (2006) Materials Science, 41, p. 597Ramirez, A.J., Lippold, J.C., (2005) Hot Cracking Phenomena in Welds, p. 19. , edited by T. Böllinghaus, H. HeroldCollins, M.G., Ramirez, A.J., Lippold, J.C., (2004) Welding Journal, 83, p. 39Yamaguchi, S., (1980) Phil. Trans. R. Soc. Lond. A, 295, p. 122Ramirez, A.J., Garzón, C.M., (2008) Hot Cracking Phenomena in Welds, 2, p. 427. , edited by T. Böllinghaus, H. Herold, C. Cross, J.C. LippoldZimina, L.N., Burova, N.N., Makushok, O.V., (1986) Met. Sci. and Heat Treatment, 28 (2), p. 130Duhl, J.M., Sullivan, C.P., (1971) Journal of Metals, pp. 38-40Torres, E.A., Paternella, F.G., Caram, R., Ramirez, A.J., (2009) 8 th International Conference on Trends in Welding Research, p. 354. , Pine-Mountain, GA-USAUnfried S, J., (2010) Mathematical Modelling of Weld Phenomena, 9, p. 983. , edited by Maney. H CerjakH K D H Bhadeshia and E KozeschnikPigrova, G.D., (2005) Metal Science and Heat Treatment, 47 (11-12), p. 544Torres, E.A., Caram, R., Ramirez, A.J., (2010) Materials Science Forum, 638-642, p. 2858Unfried S, J., Torres, E.A., Ramirez, A.J., (2011) Hot Cracking Phenomena in Welds, 3. , edited by T. Böllinghaus, H. Herold C. Cross, in pressAfonso, C.R.M., Lippold, J.C., Ramirez, A.J., (2010) Metallurgical Transactions A, , submitted t
Experimental Infection of Swine and Cat Central Nervous Systems by the Pig Paramyxovirus of the Blue Eye Disease
No full textThis study analyses whether the pig paramyxovirus of blue eye disease (PPBED) infects the central nervous system (CNS) utilizing anterograde and retrograde peripheral nerve transport systems. The virus was injected into muscle and skin, and inoculated per nasum. The presence of PPBED was detected by an immunohistochemical method using polyclonal mouse antibodies against the whole inactivated virus, and was revealed with polyclonal rabbit antibodies against mouse immunoglobulin G (IgG) labelled with peroxidase. The PPBED injected into the pig medial gastrocnemius (MG) muscle was detected in a terminal branch innervating the MG muscle, in neural fibres of the sciatic nerve, in fibres of the ventral and dorsal spinal roots and in ventral horn neurones of the spinal cord. When PPBED was injected into the skin area innervated by the sural nerve, it was detected in neural fibres of the sural and sciatic nerves and in spinal cord dorsal horn neurones. The per nasum inoculum rapidly invaded the CNS through the olfactory nerve, The.study concluded that, in order to invade the CNS, PPBED was transported retrogradely by peripheral cutaneous and muscular nerves, and anterogradely by the olfactory nerve. No PPBED was detected in either cat peripheral nerves or in cat CNS
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