4,710 research outputs found
Technology acceptance on higher education: The case of an engineer's school
Despite having distinct approaches to the Internet, Information and Communication Technology ( ICT),adults and youngsters are both actors of an active social process of learning in schools, where achanging attitude is urging. Unfortunately, schools have problems in using technology on their ownbenefit and in involving students in interesting learning activities. Additionally, teachers areuncomfortable when using technology, especially knowing their students are digital natives. So howcan we alter this scenario in order to use technology on behalf of the learning process?The pressure to use technologies for learning emerged also from the implementation of the BolognaDeclaration, which aims to harmonize the structures of Higher Education (HE). Its goal is to increasethe competitiveness of the European HE system and to promote the mobility and employability of allthe graduates. It is also intended that teachers monitor and contribute to the progress of technology bycreating new learning environments.Following these objectives, in this article, our research hypothesis is based on the premise thattechnology should be adapted to education, instead of the opposite, in order to reach higher levelsof effectiveness. Moreover, if the use of technology is not reflected in the change of educationalprocedures, the real influence on learning results is to be questioned. We believe that a change fromthe traditional education system to a model based on Web technologies implies adaptation and awillingness to implement these alterations within teaching procedures.Within the new generation of Web applications, there are a few which are shared on the sameplatform. They represent a new level of interaction that facilitates collaboration and informationsharing. They provide resources in different formats, like text, video, and audio, links to sites, notices tostudents; and they ease student/teacher interaction through communication tools, which supportcollaborative learning and registration activities. Those platforms, in general, have been used inblended-Learning (b-Learning) or as a support to face-to-face education in HE.This article analyses the current ICT usage in the context of HE, according to recent changes in theinformation society. In particular, it focuses on the adoption of online learning platforms and theirimpact in the teaching-learning model in HE, having as an example the integration of the MOODLEplatform at the Instituto Superior de Engenharia do Porto (ISEP). It was found that there is a low rateof adherence to that online teaching platform, even when used as a repository of information; also,there is a great reluctance to use the platform for b-Learning settings
Evaluation of efficient metabolic engineering strategies for accelerated co-utilisation of lactose by Saccharomyces cerevisiae
Cheese whey is the by-product of cheese production in the dairy industry and its disposal represents an environmental concern. Considering the need to implement circular bioeconomy systems, cheese whey surplus can be reused as a substrate to generate value-added compounds. Due to its high lactose content, whey is successfully integrated in multiwaste biovalorisation approaches, increasing sugar content of lignocellulose substrates[1]. In this context, the ability of cometabolization of glucose and lactose, together with yeast robustness and inhibitor tolerance, will be pivotal to develop and implement such sustainable bioprocesses. The yeast Saccharomyces cerevisiae is an attractive industrial cell factory reported to produce several chemicals of interest, from biofuels to high-value bioproducts, but it is not able to utilize lactose as carbon source. To surpass this hindrance, strategies like cloning LAC4 (-galactosidase) and LAC12 genes
(lactose permease) from Kluyveromyces sp. have been applied, but complete lactose metabolization by recombinant
strains is known to be an issue[2]. Since then, several different approaches have been studied for an efficient lactose
utilisation, as increasing the copy number of lactose-metabolization genes. However, to ensure genomic stability, it would
be preferable to limit the copy number and regulate differentially the expression of both genes. This work spans the
valorisation of cheese whey effluent using yeasts as metabolic factories. A host able to co-metabolise glucose and
galactose was used, as the choice of the yeast chassis is determinant in metabolic engineering outcomes[3]. Through the
CRISPR/Cas9 system, an industrial S. cerevisiae strain was successfully engineered with the LAC4 and LAC12 genes under
the control of different promoters. The effects of its combination were considered and the better ratio between -
galactosidase and lactose permease was evaluated. Physiological characterization of the strains constructed was
performed and optimal conditions for lactose metabolization were determined. All strains studied were capable of
consuming all lactose in the media, with the top-producing strains achieving yields near the theoretical maximum in both synthetic media and cheese whey fermentations. This study constitutes an important basis for the insertion of other metabolic pathways allowing the production of value-added compounds using cheese whey by-product as substrate and/or co-substrate.This study was developed at CEB – Centre of Biological Engineering and supported by the Portuguese Foundation for Science and Technology (FCT) - UID/BIO/04469/2020 unit; PEst UIDB/04469/2020 - Strategic Funding FCT 2020-2023; Ph.D. grant SFRH/BD/130739/2017 to Carlos E. Costa and SFRH/BD/132717/2017 to Sara L. Baptista.Referenceinfo:eu-repo/semantics/publishedVersio
Influência da modelação de elementos não estruturais no dimensionamento à acção sísmica
Realizou-se um estudo paramétrico sobre a influência de elementos não estruturais,
executados em betão, no dimensionamento de elementos estruturais de betão armado, face às
acções sísmicas regulamentares
Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy
Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review.This work was supported by the Portuguese Foundation for Science and
Technology (FCT) under the scope of the strategic funding of
UIDB/04469/2020; the Ph.D. grants SFRH/BD/130739/2017 and
SFRH/BD/132717/2017 to CEC and SLB, respectively.info:eu-repo/semantics/publishedVersio
A time of flight method to measure the speed of sound using a stereo sound card
We present an inexpensive apparatus for measuring the speed of sound, with a
time of flight method, using a computer with a stereo sound board. Students
measure the speed of sound by timing the delay between the arrivals of a pulse
to two microphones placed at different distances from the source. It can serve
as a very effective demonstration, providing a quick measurement of the speed
of sound in air; we have used it with great success in Open Days in our
Department. It can also be used for a full fledged laboratory determination of
the speed of sound in air.Comment: Accepted for publication in The Physics Teache
Evaluation of iris color stability in ocular prosthesis
Accurate iris reproduction in the fabrication of ocular prosthesis in order to match the remaining eye is a key factor to mask the loss and achieve an esthetic outcome for anophthalmic patients. This study evaluated the stability of acrylic paints used for replicating iris color in ocular prostheses by the analysis of two factors: the temperature of the acrylic resin polymerization cycle during prosthesis fabrication and the incidence of sun light, which is the main photodegrading agent undermining the longevity of ocular prostheses. An accelerated aging assay was used for both analyses. Specimens simulating the prosthetic iris in the colors blue, yellow, black, brown and green were fabricated, and were submitted to a colorimetric reading before and after undergoing the thermal conditions of acrylic resin polymerization. Next, the specimens were submitted to an artificial accelerated aging assay with ultraviolet radiation A and weekly colorimetric readings during a 3-week period. The color change (??*) values for the four specimens painted with the same color paint were averaged and the resulting values were considered for statistical analysis. Levine's test and Student's t-test were used to analyze the influence of the temperature of the polymerization cycle during prosthesis fabrication on the color stability of each acrylic resin paint. Friedman's test for three dependent samples was used for analysis of color photodegradation as function of time. Significance level was set at 0.05 for all analyses. It was observed that, after the action of the temperature of the polymerization cycle, alteration above clinically acceptable level of ??*> 3.3 was observed only for the yellow color. After the accelerated aging assay, there were statistically significant differences (p<0.05) as a function of time in the green, brown, black and blue colors. Changes were clinically acceptable for the brown and black colors; slightly above the clinically acceptable limit for the green color; and significantly high and impracticable from a clinical standpoint for the blue color. There was no statistically significant differences (p>0.05) for the yellow color, which presented color change only a little above the clinically acceptable limit. In conclusion: 1. Only the yellow color presented alterations above the clinically acceptable levels after the polymerization cycle; 2. After accelerated aging, there was no changes in the yellow color above the clinically acceptable levels; 3. For the green color, degradation was significant and slightly above the clinically acceptable levels; 4. The black, brown and blue colors presented significant alterations as function of time; the alterations of the brown and black colors were within acceptable clinical levels, while the blue color presented a more accentuated degradation over time.A fiel reprodução da íris do olho remanescente através da pintura na confecção da prótese ocular é fator fundamental no resultado estético e na dissimulação da perda para os pacientes afetados. Decidiu-se, então, avaliar a estabilidade das cores da tinta acrílica utilizada na pintura da mesma, sob a ação de dois fatores: a temperatura do ciclo de polimerização da resina acrílica e a incidência da luz solar, principal agente de fotodegradação que compromete a longevidade das próteses oculares, através de teste de envelhecimento acelerado. Foram assim, confeccionados corpos de prova simulando a íris protética, nas cores azul, amarelo, preto, marrom e verde, submetidos a uma leitura colorimétrica inicial e outra após as condições térmicas do ciclo de polimerização. Posteriormente os mesmos foram testados durante três semanas através de ensaio de envelhecimento acelerado artificialmente com radiação ultravioleta A e leituras colorimétricas semanais. Através dos valores da alteração de cor (DE*) foi obtida uma média para as quatro amostras pintadas com a mesma cor e os valores resultantes foram submetidos à análise estatística. Os testes de Levine e t de Student foram utilizados para analisar a influência da temperatura do processo de polimerização na estabilidade de cada cor utilizada na fabricação das próteses. O teste de Friedman para três amostras dependentes foi usado para analisar a degradação de cor em função do tempo. O nível de significância foi de 0,05 para todas as análises. Após a ação da temperatura do ciclo de polimerização, observou-se que somente na cor amarelo ocorreu alteração acima do nível clinicamente aceitável (p<0,05). Após o ensaio de envelhecimento, ocorreram diferenças estatisticamente significantes em função do tempo nas cores verde, marrom, preto e azul. A variação de cor ocorreu em níveis considerados clinicamente aceitáveis para as cores marrom e preto; levemente acima dos níveis clinicamente aceitáveis para a cor verde; e em níveis elevados, inviáveis clinicamente para a cor azul. Na cor amarelo não houve diferenças estatisticamente significantes (p>0,05), com alteração apenas um pouco acima do limite considerado clinicamente aceitável. Em conslusão: 1. Somente a cor amarelo apresentou alteração acima dos níveis clinicamente aceitáveis após o ciclo de polimerização; 2. Após o envelhecimento artificial, não houve alterações na cor amarelo acima dos níveis clinicamente aceitáveis; 3. Para a cor verde, a degradação foi significante e um pouco acima dos níveis clinicamente aceitáveis; 4. As cores preto, marrom e azul apresentaram diferenças significantes em função do tempo; as alterações das cores marrom e preto foram em níveis clinicamente aceitáveis, enquanto a cor azul apresentou um elevado índice de degradação de cor em todo tempo
The role of intratumoral lymphovascular density in distinguishing primary from secondary mucinous ovarian tumors
OBJECTIVE: Ovarian mucinous metastases commonly present as the first sign of the disease and are capable of simulating primary tumors. Our aim was to investigate the role of intratumoral lymphatic vascular density together with other surgical-pathological features in distinguishing primary from secondary mucinous ovarian tumors. METHODS: A total of 124 cases of mucinous tumors in the ovary (63 primary and 61 metastatic) were compared according to their clinicopathological features and immunohistochemical profiles. The intratumoral lymphatic vascular density was quantified by counting the number of vessels stained by the D2-40 antibody. RESULTS: Metastases occurred in older patients and were associated with a higher proportion of tumors smaller than 10.0 cm; bilaterality; extensive necrosis; extraovarian extension; increased expression of cytokeratin 20, CDX2, CA19.9 and MUC2; and decreased expression of cytokeratin 7, CA125 and MUC5AC. The lymphatic vascular density was increased among primary tumors. However, after multivariate analysis, the best predictors of a secondary tumor were a size of 10.0 cm or less, bilaterality and cytokeratin 7 negativity. Lack of MUC2 expression was an important factor excluding metastasis. CONCLUSIONS: The higher intratumoral lymphatic vascular density in primary tumors when compared with secondary lesions suggests differences in the microenvironment. However, considering the differential diagnosis, the best discriminator of a secondary tumor is the combination of tumor size, laterality and the pattern of expression of cytokeratin 7 and MUC2
Association between intratumoral lymphatic microvessel density (LMVD) and clinicopathologic features in endometrial cancer: a retrospective cohort study
<p>Abstract</p> <p>Background</p> <p>Lymph node metastasis in endometrial cancer significantly decreases survival rate. Few data on the influence of intratumoral lymphatic microvessel density (LMVD) on survival in endometrial cancer are available. Our aim was to assess the intratumoral LMVD of endometrial carcinomas and to investigate its association with classical pathological factors, lymph node metastasis and survival.</p> <p>Methods</p> <p>Fifty-seven patients with endometrial carcinoma diagnosed between 2000 and 2008 underwent complete surgical staging and evaluation of intratumoral LMVD and other histologic variables. Lymphatic microvessels were identified by immunohistochemical staining using monoclonal antibody against human podoplanin (clone D2-40) and evaluated by counting the number of immunostained lymphatic vessels in 10 hot spot areas at 400× magnification. The LMVD was expressed by the mean number of vessels in these 10 hot spot microscopic fields. We next investigated the association of LMVD with the clinicopathologic findings and prognosis.</p> <p>Results</p> <p>The mean number of lymphatic vessels counted in all cases ranged between 0 and 4.7. The median value of mean LMVD was 0.5, and defined the cut-off for low and high LMVD. We identified low intratumoral LMVD in 27 (47.4%) patients and high LMVD in 30 (52.6%) patients. High intratumoral LMVD was associated with lesser miometrial and adnaexal infiltration, lesser cervical and peritoneal involvement, and fewer fatal cases. Although there was lower lymph node involvement among cases with high LMVD, the difference did not reach significance. No association was seen between LMVD and FIGO staging, histological type, or vascular invasion. On the other hand, low intratumoral LMVD was associated with poor outcome. Seventy-five percent of deaths occurred in patients with low intratumoral LMVD.</p> <p>Conclusion</p> <p>Our results show association of high intratumoral LMVD with features related to more localized disease and better outcome. We discuss the role of lymphangiogenesis as an early event in the endometrial carcinogenesis.</p
A Filmagem de Apresentações Orais: Desenvolvimento da Consciência da Competência Oral nos Aprendentes de Língua Estrangeira.
Esta investigação tem como objetivo ajudar os alunos a desenvolver a sua consciência dos pontos fortes e fracos das suas apresentações orais, levando-os a refletir mais aprofundadamente acerca do seu deeempenho, para poderem mais facilmente melhorar os aspetos menos bem conseguidos. A câmara de filmar é o instrumento de recolha mais importante para a execução do projeto, permitindo tanto ao professor como aos alunos observar mais detalhadamente os trabalhos. A análise decorrente dessa observação é, sem dúvida, essencial para o processo de conciencialização. Este processo é constituído por um primeiro momento de autoavaliação, seguido pela heteroavaliação e culminando no meu feedback, em resposta às observações dos alunos e com vista a tornar esta análise mais produtiva e benéfica para eles.This action research intends to help the students to develop their awareness of the strengths and weaknesses of their oral presentations in a foreign language, guiding them to reflect more deeply on their performance, in order to be able to improve it. The video camera is the most important data-gathering tool for the implementation of this project, enabling both the teacher and the students to observe the presentations more thoroughly. The analysis resulting from that observation is, undoubtedly, essential to developing the process of awareness. This process is comprised by a first moment of self-evaluation, followed by peer evaluation and culminating in the teacher's feedback, commenting on the students' observations with the aim of enriching this analysis in order to help students improve their performance
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