Browsing by resource type "preprint"
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- O amor do Deus de Jesus Cristo e o seu reflexo na famíliaPublication . Carvalho, José Carlos Silva
- An SNF2 helicase-like protein links mitotic transcription termination to sister chromatid resolutionPublication . Carmo, Catarina; Coelho, João; Silva, Rui; Tavares, Alexandra; Boavida, Ana; Gaetani, Paola; Martinho, Rui Gonçalo; Oliveira, Raquel A.Mitotic chromatin is largely assumed incompatible with transcription due to changes in the transcription machinery and chromosome architecture. However, the mechanisms of mitotic transcriptional inactivation and their interplay with chromosome assembly remain largely unknown. By monitoring ongoing transcription in Drosophila early embryos, we reveal that eviction of nascent mRNAs from mitotic chromatin occurs after substantial chromosome compaction and is not promoted by condensin I. Instead, we show that the timely removal of transcripts from mitotic chromatin is driven by the SNF2 helicase-like protein Lodestar (Lds), identified here as a modulator of sister chromatid cohesion defects. In addition to transcriptional termination, we uncovered that Lds cooperates with Topoisomerase 2 to ensure efficient sister chromatid resolution and mitotic fidelity. We conclude that mitotic transcriptional termination is not a passive consequence of cell cycle progression and/or chromosome compaction but occurs via dedicated mechanisms with functional parallelisms to sister chromatid resolution.
- An uplifting avenue upon mealworm chitosan for hemodialysis applicationPublication . Martingo, Maria; Baptista-Silva, Sara; Mesquita, Raquel; Ferreira, João Paulo; Borges, Sandra; Pintado, ManuelaChronic kidney disease (CKD) is characterized by a continuous decline in kidney function, often persisting for years or even a lifetime. This study presents a new exploration into the extraction and application of insect chitosan (Tenebrio molitor) targeting hemodialysis (HD). Initially, the potential of insect-derived chitosan as a sustainable and effective alternative to traditional sources (i.e. crustaceans) is demonstrated. Efficient extraction methods were developed (totaling between 6 h and 12 h), producing chitosan. Firstly, chitin was efficiently isolated from T. molitor through deproteinization and demineralization, with yields of approximately 5% (w/w). Subsequently, chitosan was obtained from the extracted chitin resulting in yields of between 65.0 ± 0.8% (w/w) and 79.3 ± 0.8% (w/w). Characterization using Fourier Transform Infrared Spectroscopy (FTIR) confirmed structural similarities with commercial chitosan and degrees of deacetylation in the 73 - 75% range. The bioactive properties of chitosan obtained from T. molitor, including antimicrobial and antioxidant activities, were evaluated. All the microorganisms tested were inhibited, exhibiting minimum lethal concentrations between 2 and 8 mg/mL, confirming the antimicrobial activity of the extracted chitosan. In addition, chitosan showed antioxidant activity in the range of 60 to 65 µmol Trolox equivalent/g, suggesting its viability for various medical applications. This study also developed a chitosan-based membrane (CH - M) culminating in a proof-of-concept phase for hemodialysis. The permeation characteristics of CH-M for urea and albumin were studied in vitro to assess their suitability as HD membranes. Urea was permeable to values of over 70% and albumin was retained.
- Assigning patients to healthcare centers using dispatching rulesPublication . Teymourifar, Aydin; Trindade, Maria A. M.This study proposes a model for the balanced assignment of patients to healthcare centers in a region. In the suggested model, it is supposed that patients want to go to the nearest center, which causes an imbalance in the workloads of resources between centers. This disproportion is undesirable not only for the centers but also for the patients. Thus, balancing assignments is targeted. This goal is expressed in a model with a multi-objective function. Since balancing is one of the main goals of the sectorization concept, we characterize the model based on it. Unlike studies in the literature, we do sectorization employing dispatching rules. This diminishes the problem's complexity and makes it suitable for solving actual, large, and dynamic problems. We simulated the system using the Rockwell Arena software. We consider the effect of different seasons, days, and hours on the system. The dispatching rule used for sectorization is optimized using the OptQuest software. The numerical results demonstrate that by optimizing the dispatching rule, it is possible to enhance the objective function significantly.
- Banco Espírito Santo: the anatomy of a banking skandalPublication . Antunes, José EngráciaThe “Banco Espírito Santo” (BES) was the oldest and one of the largest Portuguese banks: it was created in 1869, precisely at the same year that Goldman Sachs was founded, and it was resolved in 2014.The present paper aims to briefly explain how a centenary bank, that survived to two World Wars, prevailed over different political regimes (Monarchy, Republic, a Revolution), and endured diverse economic regimes (nationalization, subsequent reprivatisation), has come to an abrupt end.
- Bank risk-taking and impaired monetary policy transmissionPublication . Koenig, Philipp; Schliephake, EvaWe consider a standard banking model with agency frictions to simultaneously study the weakening and reversal of monetary transmission and banks’ risk-taking in a low-interest environment. Both, weaker monetary transmission and higher risk-taking arise because lower policy rates impair banks’ net worth.The pass-through to deposit rates, the level of excess reserves and the extent of the agency problem between banks and depositors are crucial determinants of monetary transmission. If the deposit pass-through is sufficiently impaired, a reversal rate exists. For policy rates below the reversal rate further interest rate reductions lead to a disproportionate increase in risk-taking and a contraction in loan supply.
- Bio-based superabsorbent hydrogels for nutrient-controlled releasePublication . Ribeiro, Alessandra B.; Moreira, Helena; Pereira, Sofia I. A.; Godinho, Mariana; Castro, Paula; Pereira, Carla F.; Casanova, Francisca; Freixo, Ricardo; Pintado, Manuela E.; Ramos, Óscar L.The drought is characterized by a low water precipitation rate, with strong impact on the crop productivity, threaten global food production. In this context, the use of soil amendments, such as superabsorbent hydrogels constitute a potential technology for water use efficiency and increase crop yields. In this work, it was synthesised a cellulose-based hydrogel, carrying out its characterisation, evaluated its environmental safety and its potential to be used as a soil amendment. The hydrogel was successfully synthesised using a simple process and inexpensive reagents. The hydrogel showed pH of 6.0 to 7.5 and conductivity below 10.0 µS cm-1. The FTIR showed a low intensity peak in the crystallinity region, which was supported by the low crystallinity index (27.3 % ± 0.6) verified by PXRD analysis. The swelling capacity reached more than 200 g of water, the hydrogel showed good resistance to osmotic pressure and high thermostability, which favours the application in hot and arid areas. Regarding the safety evaluation, no potentially hazardous compound was detected, nor was there any adverse effect on soil microrganisms. In addition, the hydrogel was found to be safe for use during sowing and for promoting seedling development. In the green pot experiment, the hydrogel demonstrated a significant increase in maize biomass, root biomass and potential to serve as a reservoir for soil nutrients. In conclusion, the superabsorbent hydrogel exhibited promising characteristics for use as a soil amendment, scalability potential and constitutes a sustainable alternative for agricultural applications.
- Debt financing choices: theory and evidence from EuropePublication . Pinto, João; Santos, Mário C.We examine the factors that influence borrower’s choice between structured finance (SF) and straight debt finance (SDF). Using a sample of 12,075 Western European loans and bonds issued between 2000 and 2011, we find that borrowers choose SF when they seek long-term financing and funding cost reduction. Our results document that floatation costs, information asymmetry, and renegotiation and liquidation risks affect non-financial firms’ financing decisions. We also find that banks choose securitization to raise relatively large amounts of debt and improve economic performance. Our overall findings support hypotheses of SF as mechanism for asymmetric information problem and principal-agent conflict reduction.
- Domestic Impact of Internationalisation the case of JMPublication . Ferreira, Mário Pedro; Silva, Susana Costa eThe influence of internationalisation processes in the domestic activities of firms’ has not been considered as an important issue in existing models, because they tend to focus on a partial and restricted view of the firm. The purpose of this paper is to challenge that view by attempting a dynamic view of the firm is which primal importance is given to the relationship between international and domestic activities. The main research question is whether domestic activities can be significantly affected by international activities, namely knowledge transfer. Results confirm the dynamic approach adopted by firms however there are no definitive answers in terms of the domestic impact of internationalisation. Despite clear hints of evidence for the internationaldomestic relationship, there was no confirmation of this relationship at the financial level.
- Dynamic resectorization to improve utility of healthcare systemsPublication . Teymourifar, Aydin; Trindade, Maria A. M.This study discusses a regional healthcare system including several hospitals with different characteristics. We define a utility function for the system based on the sectorization concept to form a balance between hospitals in terms of important outputs such as waiting times and demands. Since the determined system is dynamic, the balance state is lost over time; consequently, resectorization is done over time. We simulate the system utilizing the data of a case study. We characterize multiple periods and calculate the utility of the system's current state. We design resectorization scenarios based on boosting the capacity and quality of hospitals. Numerical results demonstrate that substantial improvement of utility with resectorization is achievable.