The potential of microalgae in feed for Atlantic salmon (Salmo salar L.)

Masteroppgave i havbruk - Universitetet i Nordland, 2015Sperra for utlån til 2018-06-2

Mogućnost korišćenja mikroalgi u hrani za karnivorne vrste riba

Potreba za sastojcima visokog kvaliteta u proizvodnji hrane za ribe raste zajedno sa razvojem proizvodnje u akvakulturi u svetu. Riblje brašno i riblje ulje su najčešće birani sastojci za hranu za ribe zbog njihove visoke nutritivne vrednosti i ukusa. Riblje brašno sadrži onu količinu amino kiselina koja je ribi potrebna. Riblje ulje je odličan izvor esencijalnih n-3 masnih kiselina dugog lanca, koje su veoma važne za unapređenje zdravlja, kako kod riba tako i kod onih koji konzumiraju ribu. Riblje brašno i ulje su zamenjivani biljnim sastojcima u proteklih 25 godina. Međutim, biljn sastojci često sadrže širok spektar anti-nutririvnih sastojaka koji imaju negativan uticaj na zdravlje ribe kao i korišćenje hrane za ribe. Ulje biljnog porekla u hrani za ribe menja sastav masnih kiselina u tkivu ribe, umanjuje povoljan profil masnih kiselina pa dominiraju manje pogodne n-6 masne kiseline. Postoji sve veća zainteresovanost za pronalaženjem izvora hrane za ribe u nižim trofičkim nivoima morskih ekosistema, kao što su mikroalge. Morske mikroalge su primarni proizvođači n-3 masnih kiselina i zbog toga su verovatno bolja alternativa za riblje ulje od biljnog. Neke mikroalge imaju odgovarajući sastav proteina kao i profil amino kiselina. Cilj ovog eksperimenta je da istraži nutritivnu svarljivost (ADC) suve materije (DM), proteina i pepela mikroalgi Nanofrustulum (C3), Desmodesmus (C4) i Nannochloropsis (C1) koji su inkorporirani u hranu za Atlantskog lososa, Salmo salar. Dva testa svarljivosti su urađena sa Atlantskim lososom. Cilj prvog ekperimenta (inicijalni test, P, prosečna inicijalna težina ribe 1000g) bio je da istraži svarljivost sastojaka 3 alge tako što je kontrolna hrana bazirana na ribljem brašnu rastvorena sa 30% test sastojka (u odnosu 70:30). Ove tri vrste hrane su proizvedene hladnim procesom peletiranja. Drugi eksperiment (ekperiment provere, V; prosečna inicijalna težina ribe 436g), urađen je da bi potvrdio rezultate C1 i C4 korišćenjem ekstrudirane hrane. Feces je sakupljan metodom ceđenja. U oba eksperimenta, primećene su značajne razlike u svarljivosti ADC mikroalgi. Sveukupno, najviša ADC za proteine, DM i pepeo (P<0.05) utvrđena je kod hrane C3, dok nije bilo značajnih razlika između C1 i C4. Kada je reč o eksperimentu V, najviša ADC suve materije i proteina utvrđena je za hranu C1 (P<0.05), dok se razlika ADC pepela nije pokazala među različitim tipovima hrane. ADC proteina i suve materije je bio u istom opsegu kao i vrednosti eksperimenta P, dok je ADC pepela bio viši. Nutritivna svarljivost varira među različitim vrstama mikroalgi. Ona verovatno takođe zavisi od tehnoloških uslova procesuiranja hrane. Zasnovano na ADC vrednostima, iako je C3 pokazala bolji potencijal, njen visok sastav pepela i nizak sastav proteina, mogu biti ograničavajući factor za korišćenje ove mikroalge u ishrani za ribe. Velike razlike nisu pronađene u vrednostima svarljivosti između algi C1 i C4. Ova zapažanja treba dalje potvrditi dugoročnim eksperimentima hranjenja Atlantskog lososa da bi se u potpunosti definisao potencijal sva tri kandidata. Ova studija je deo projekta “Proizvodnja velikih dimenzija goriva i hrane iz mikroalgi”. Projekat je finansiran od strane Odeljenja za Energiju Sjedinjenih Američkih Država

Evolución de las Estrategias de Desarrollo Turístico en México

El estudio forma parte de un análisis de las estrategias de desarrollo del turismo en México en los últimos quince años, de acuerdo al flujo de turistas que le han impulsado al desarrollo económico en la era de la globalización, ubicando su realidad como país emergente en donde el turismo forma parte fundamental aportando un nueve por ciento al producto interno bruto, por la generación de la actividad turística, con una riqueza natural y cultural que lo hace aún más atractivo, para el enorme flujo de visitantes extranjeros que visitan el país, es necesario hacer una revisión histórica de las políticas públicas, las estrategias de promoción que se han llevado acabo para articular al turismo con el desarrollo

The Mechanism of Abrupt Transition between Theta and Hyper-Excitable Spiking Activity in Medial Entorhinal Cortex Layer II Stellate Cells

Recent studies have shown that stellate cells (SCs) of the medial entorhinal cortex become hyper-excitable in animal models of temporal lobe epilepsy. These studies have also demonstrated the existence of recurrent connections among SCs, reduced levels of recurrent inhibition in epileptic networks as compared to control ones, and comparable levels of recurrent excitation among SCs in both network types. In this work, we investigate the biophysical and dynamic mechanism of generation of the fast time scale corresponding to hyper-excitable firing and the transition between theta and fast firing frequency activity in SCs. We show that recurrently connected minimal networks of SCs exhibit abrupt, threshold-like transition between theta and hyper-excitable firing frequencies as the result of small changes in the maximal synaptic (AMPAergic) conductance. The threshold required for this transition is modulated by synaptic inhibition. Similar abrupt transition between firing frequency regimes can be observed in single, self-coupled SCs, which represent a network of recurrently coupled neurons synchronized in phase, but not in synaptically isolated SCs as the result of changes in the levels of the tonic drive. Using dynamical systems tools (phase-space analysis), we explain the dynamic mechanism underlying the genesis of the fast time scale and the abrupt transition between firing frequency regimes, their dependence on the intrinsic SC's currents and synaptic excitation. This abrupt transition is mechanistically different from others observed in similar networks with different cell types. Most notably, there is no bistability involved. ‘In vitro’ experiments using single SCs self-coupled with dynamic clamp show the abrupt transition between firing frequency regimes, and demonstrate that our theoretical predictions are not an artifact of the model. In addition, these experiments show that high-frequency firing is burst-like with a duration modulated by an M-current

Cartografia e diplomacia: usos geopolíticos da informação toponímica (1750-1850)

O artigo explora dimensões geopolíticas da toponímia, registradas em documentos cartográficos, desde as reformas empreendidas pelo consulado pombalino em meados do século XVIII, até às primeiras décadas do século XIX, em meio ao processo de afirmação do Estado imperial pós-colonial.This paper explores the geopolitical dimensions of toponymy as registered in cartographic documents dating from the reforms pushed through by the consulate of Marquis of Pombal in the mid 18th century to the early decades of the 19th century, as the post-colonial imperial State established itself

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030