Assessing inter-beach differences in semi-terrestrial arthropod assemblages on Maltese pocket sandy beaches (Central Mediterranean)

The distinctiveness of macrofaunal assemblages on different sandy beaches in the Maltese Islands was previously suggested by different single-season studies. A multi-seasonal sampling programme using pitfall trapping was implemented on four Maltese beaches to test the occurrence of this phenomenon. A total of 29,302 individuals belonging to 191 species were collected over a 2-year period, during which the beaches were sampled once per calendar season. A total of 77 species were recorded from single Maltese beaches only, of which nine were psammophiles. Non-metric multidimensional scaling analyses of pitfall trap species-abundance data resulted in a weak separation pattern, with samples grouping mainly in terms of beach and island rather than in terms of season or year of sampling, No physical variable could conclusively explain these patterns. It is concluded that although operating on Maltese beaches, macrofaunal assemblage distinctiveness is weaker than originally thought and can be attributed to the presence/absence or abundance of just a few psammophilic species. It is postulated that this phenomenon may be related to the ‘pocket beach’ nature of Maltese beaches, where headlands on either side of the beach to a large extent prevent the occurrence of longshore currents, resulting in semi-isolation of the populations of psammophilic species. A large number of single-beach records reported in this study highlight the high degree of beta diversity and spatial heterogeneity of Maltese beaches, and the conservation importance of the individual beach macrofaunal assemblages.peer-reviewe

Adaptation of sea turtles to climate warming: Will phenological responses be sufficient to counteract changes in reproductive output?

Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regimes. Here, we assessed the extent to which phenological shifts could mitigate impacts from increases in ambient temperatures (from 1.5 to 3°C in air temperatures and from 1.4 to 2.3°C in sea surface temperatures by 2100 at our sites) on four species of sea turtles, under a “middle of the road” scenario (SSP2-4.5). Sand temperatures at sea turtle nesting sites are projected to increase from 0.58 to 4.17°C by 2100 and expected shifts in nesting of 26–43 days earlier will not be sufficient to maintain current incubation temperatures at 7 (29%) of our sites, hatching success rates at 10 (42%) of our sites, with current trends in hatchling sex ratio being able to be maintained at half of the sites. We also calculated the phenological shifts that would be required (both backward for an earlier shift in nesting and forward for a later shift) to keep up with present-day incubation temperatures, hatching success rates, and sex ratios. The required shifts backward in nesting for incubation temperatures ranged from −20 to −191 days, whereas the required shifts forward ranged from +54 to +180 days. However, for half of the sites, no matter the shift the median incubation temperature will always be warmer than the 75th percentile of current ranges. Given that phenological shifts will not be able to ameliorate predicted changes in temperature, hatching success and sex ratio at most sites, turtles may need to use other adaptive responses and/or there is the need to enhance sea turtle resilience to climate warming.18 página

Addressing Profiles of Systemic Inflammation Across the Different Clinical Phenotypes of Acutely Decompensated Cirrhosis

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Blood metabolomics uncovers inflammation-associated mitochondrial dysfunction as a potential mechanism underlying ACLF (vol 72, pg 688, 2020)

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Development of an anthropomorphic robot hand and wrist for teleoperation applications

In this work, we are developing an anthropomorphic robot hand and wrist to be teleoperated by a human using a glove input device. The present model of the hand is intended for use in grasping operations, and consists of a palm, two fingers, an opposed thumb, and two wrist joints that provide pitch and roll movements. Each of the three digits of the robot hand has two pitch joints to enable flexion and extension, and incorporates a new passive switching mechanism that allows a single actuator to drive the two joints successively. The hand/wrist system has a total of five independent degrees-of-freedom. It is driven by five remotely located DC motors through servo control, and the drive from the motors is transmitted to the hand and wrist joints through flexible sheathed cables acting as tendons. The work focuses on replicating as closely as possible the shape, size, natural motions and applied forces of the human appendage, while keeping the complexity of the robot hand and wrist to a minimum. The first prototype of the hand has been demonstrated, and is capable of holding a wide variety of objects of different shapes and sizes using both precision-type and power-type grasp configurations

Adaptatividad tridimensional con mallas no estructuradas

In this work some experiences on adaptivity for three dimensional problems are presented. Based on a linear elasticity solver, two different approach for the discretization changes are analysed: subdivision of simplexes and remeshing. With the first one, those elements with an estimated error greater than an acceptable value are divided. With the second, the estimated error is used to define a new element size at the centre of each element and a new mesh is generated. Both methods are described and some application examples are presented. Finally the advantage and problems of using these adaptivity techniques are discussed