Understanding scientific application's performance

Improve Earth System model's scalability in High Performance Computing infrastructure is crucial to achieve efficiency in upcoming supercomputers. We study how to increase the scalability of the widely used Oceanic Model of the Nucleus for European Modelling of the Ocean (NEMO)

Exploring the use of mixed precision in NEMO

It has been a widely extended practice in scientific computing to use 64-bit to represent data without even considering which level of precision is really needed. In many applications, 32-bit should provide enough accuracy, and in other cases 64-bit is not enough. In climate science, the inherent difficulties collecting data imply a considerable level of uncertainty, which suggest that the general use of 64-bit to represent the data may be a waste of resources, while on the other hand, some specific algorithms could benefit from an increment of the precision used. These factors suggest that in the future more attention has to be paid to the precision used in scientific software, to use the resources wisely and also avoid losing accuracy. In this work we question whether the precision used in the oceanic model NEMO is necessary and sufficient, and the potential benefits of adjusting this precision

Does intrauterine crowding affect the force generating capacity and muscle composition of the piglet front limb?

In the pig, intrauterine competition (IUC) greatly affects postnatal traits, such as birth weight, but also locomotor capacities. In a previous study, our group discovered a lower motor performance in piglets with a low birth weight and low vitality (L piglets), compared to piglets with a normal birth weight and normal vitality (N piglets). In order to explain the force deficit causing this reduced motor performance, in a subsequent study, we investigated whether this deficit in L piglets was caused by a lower force generating capacity (FGC) of the extensors of the hind limb and/or a lower number of type II (fast-twitch) fibers in m. vastus lateralis. L piglets had a lower absolute FGC, but surprisingly, a higher relative FGC (to birth weight) in the hind limb, compared to N piglets. In addition, we found no differences in fiber composition of m. vastus lateralis. In the present study, we assessed whether this higher relative FGC is a common feature for front and hind limb locomotor muscles of L piglets. To that end, the physiological cross-sectional area of the main extensor muscles of the front limb was calculated from their volume and fiber length, in order to calculate both the absolute and the relative FGC. By immunohistochemical staining of m. triceps brachii caput longum, the percentage of type II (fast-contracting) fibers could be determined. Similar to the results of the hind limb, we found a smaller absolute FGC, but a larger relative FGC in the front limb of L piglets, compared to N piglets. In addition, m. triceps brachii caput longum did not have a different muscle fiber composition in L and N piglets. As such, we can conclude that IUC affects the locomotor muscles in the front and hind limb in a similar way and that the observed force deficit in L piglets cannot be explained by a different force generating capacity or a lower percentage of type II muscle fibers

Glucose and glycogen levels in piglets that differ in birth weight and vitality

In the pig, intrauterine crowding can greatly affect postnatal characteristics, among which birth weight and locomotion. In a previous study, we discovered that piglets with a low birth weight/low vitality (L piglets) have a reduced motor performance compared to piglets with a normal birth weight/normal vitality (N piglets). A possible explanation is that L piglets lack the energy to increase their motor performance to the level of that of N piglets. Blood glucose levels (GLU) and glycogen concentrations in skeletal muscle of the front (GLYFRONT) and hind leg (GLYHIND) and the liver (GLYLIVER) at birth and during the first 96 h postpartum were compared between L and N piglets. GLU at birth was the same for both groups. After birth, GLU immediately increased in N piglets, whereas it only increased after 8 h in L piglets. L piglets showed a lower GLYHIND at birth and did not use this glycogen during the first 8 h postpartum, while N piglets showed a gradual depletion. GLYLIVER at birth was 50% lower for L piglets and was unused during the studied period while N piglets consumed half of their GLYLIVER during the first 8 h. Based on these results, it is possible that lower glycogen concentrations at birth, the delayed increase in GLU and the lower use of glycogen during the first 8 h after birth negatively affect motor performance in L piglets. However, based on this study, it is unclear whether the low mobilization of glycogen by L piglets is a consequence, rather than a cause of their lower motor performance

Information resources in Economics, Business and Statistics

Presentation of 4 databases of Economics, Business and Statistics, to be presented during 15 min in a master of Economic

Artificial rearing influences the morphology, permeability and redox state of the gastrointestinal tract of low and normal birth weight piglets

Background: In this study the physiological implications of artificial rearing were investigated. Low (LBW) and normal birth weight (NBW) piglets were compared as they might react differently to stressors caused by artificial rearing. In total, 42 pairs of LBW and NBW piglets from 16 litters suckled the sow until d19 of age or were artificially reared starting at d3 until d19 of age. Blood and tissue samples that were collected after euthanasia at 0, 3, 5, 8 and 19 d of age. Histology, ELISA, and Ussing chamber analysis were used to study proximal and distal small intestine histo-morphology, proliferation, apoptosis, tight junction protein expression, and permeability. Furthermore, small intestine, liver and systemic redox parameters (GSH, GSSG, GSH-Px and MDA) were investigated using HPLC. Results: LBW and NBW artificially reared piglets weighed respectively 40 and 33% more than LBW and NBW sow-reared piglets at d19 (P < 0.01). Transferring piglets to a nursery at d3 resulted in villus atrophy, increased intestinal FD-4 and HRP permeability and elevated GSSG/GSH ratio in the distal small intestine at d5 (P < 0.05). GSH concentrations in the proximal small intestine remained stable, while they decreased in the liver (P < 0.05). From d5 until d19, villus width and crypt depth increased, whereas PCNA, caspase-3, occludin and claudin-3 protein expressions were reduced. GSH, GSSG and permeability recovered in artificially reared piglets (P < 0.05). Conclusion: The results suggest that artificial rearing altered the morphology, permeability and redox state without compromising piglet performance. The observed effects were not depending on birth weight

Josep Miquel Ramis (ed.), «Epistolari Sebastià Juan Arbó - Joan Sales (1966-1982)», Barcelona, Publicacions de l?Abadia de Montserrat («Textos i Estudis de Cultura Catalana», 221), 2018, 167 pp.

Ressenya sobre el llibre de Josep Miquel Ramis (ed.), Epistolari Sebastià Juan Arbó - Joan Sales (1966-1982), Barcelona, Publicacions de l?Abadia de Montserrat («Textos i Estudis de Cultura Catalana», 221), 2018, 167 pp., ISBN: 978-84-9883-956-2

How does intrauterine crowding affect locomotor performance in newborn pigs? : a study of force generating capacity and muscle composition of the hind limb

Intrauterine crowding (IUC) considerably influences postnatal traits in a polytocous species such as the pig. Previously, our group described how IUC affects locomotion during the piglet's first days of life (until 96 h after birth). We noted a reduced motor performance in piglets with a low birth weight and low vitality (L piglets), compared to piglets with a normal birth weight and normal vitality (N piglets), indicating L piglets are unable to produce enough force. Our current study investigates whether this observed force deficit in L piglets is caused by a reduced force generating capacity in the muscles and/or a lower percentage of type II (fast-contracting) fibers. Volume and fiber length of the main extensor muscles of the hind limb were used to estimate the physiological cross-sectional area (PSCA) and hence calculate the maximal isometric force generating capacity (Fiso-max) of the hind limb. To check for developmental differences between the muscles of L and N piglets, Fiso-max was normalized to body weight (BW), thus yielding a dimensionless variable F'iso-max. To check for differences in muscle composition, m. vastus lateralis was stained immunohistochemically in order to determine the percentage of type II fibers through image analysis. Our results indicate that L piglets have a reduced absolute force generating capacity due to a lesser muscle mass, compared to N piglets. However, when normalized to BW L piglets actually show a larger force generating capacity, suggesting their muscles are more voluminous, given their body mass, than those of N piglets. However, no differences between L and N piglets were detected with regard to muscle composition of the m. vastus lateralis. Based on our data, we can say that neither normalized force generating capacity, nor muscle composition (of the m. vastus lateralis) can explain the observed force deficit in L piglets and as such the effect of IUC on locomotor performance