Hironaka's characteristic polygon and effective resolution of surfaces

Hironaka's concept of characteristic polyhedron of a singularity has been one of the most powerful and fruitful ideas of the last decades in singularity theory. In fact, since then combinatorics have become a major tool in many important results. However, this seminal concept is still not enough to cope with some effective problems: for instance, giving a bound on the maximum number of blowing--ups to be performed on a surface before its multiplicity decreases. This short note shows why such a bounding is not possible, at least with the original definitions.Comment: 7 pages, 1 figur

On simultaneous arithmetic progressions on elliptic curves

In this paper we study elliptic curves which have a number of points whose coordinates are in arithmetic progression. We first motivate this diophantine problem, prove some results, provide a number of interesting examples and, finally point out open questions which focus on the most interesting aspects of the problem for us.Comment: 22 page

Equimultiple Locus of Embedded Algebroid Surfaces and Blowing–up in Characteristic Zero

2000 Mathematics Subject Classification: 14B05, 32S25.The smooth equimultiple locus of embedded algebroid surfaces appears naturally in many resolution processes, both classical and modern. In this paper we explore how it changes by blowing–up.* Supported by FQM 304 and BFM 2000–1523. ** Supported by FQM 218 and BFM 2001–3207

Optimal design parameters of auv hull based on cfd simulation

Peer Reviewe

Determining the psychophysiological responses of military aircrew when exposed to acute disorientation stimuli

Introduction: Exposure to enviromental flight conditions may impair performance and physical integrity, thus training in simulated environments it is a key factor. This research aimed to study the psychophysiological response, cortical arousal and autonomic modulation of pilots and medical aircrew personnel during disorientation exposure, considering gender, experience, flying hours and body mass index (BMI) as influencial variables. Methods: A total of 47 soldiers (37 men and 10 women, 22 medical aircrew personnel and 25 fighter pilots) of Spanish Air Forces faced 25 min of vestibular, proprioceptive and visual disorientation. Results: Disorientation exposure elicited an increased psychophysiological response, significant increases in isometric hand strength, cortical arousal, autonomic modulation, perceived stress and effort in both groups while a significant decrease in respiratory muscle capacity and blood oxygen saturation in the medical aircrew group were found. Cross-sectional analysis showed gender differences, males presented greater parasympathetic activity and strength. Larger BMI was associated with greater levels and perception of stress as well as lower cardiovascular performance and sympathetic modulation. Furthermore, experience, previous training and larger flying hours correlated with greater parasympathetic modulation. Conclusion: Disorientation exposure produces an increase in cortical arousal and decrease in the parasympathetic nervous system either in pilots and medical aircrew personnel. In addition, medical aircrew personnel are less adapted to disorientation stimulus presenting significantly higher psychophysiological stress response, thus complementary physical training should be mandatory

Acoustic assessment and distribution of the main pelagic fish species in ICES Subdivision 9a South during the ECOCADIZ-RECLUTAS 2018-10 Spanish survey (October 2017).

The present working document summarises the main results obtained during the ECOCADIZ-RECLUTAS 2018-10 Spanish (pelagic ecosystem-) acoustic survey. The survey was conducted by IEO between 10th and 29th October 2018 in the Portuguese and Spanish shelf waters (20-200 m isobaths) off the Gulf of Cadiz onboard the R/V Ramón Margalef. The survey’s main objective is the acoustic assessment of anchovy and sardine juveniles (age 0 fish) in the recruitment areas of the Gulf of Cadiz. The 21 foreseen acoustic transects were sampled. A total of 25 valid fishing hauls were carried out for echo-trace ground-truthing purposes. Chub mackerel was the most frequent species in those hauls, followed by sardine, anchovy, horse mackerel, mackerel, bogue and Mediterranean horse mackerel. Acoustic sampling was carried out with the recently installed Simrad™ EK80 echo-sounder working in multi-frequency and in CW mode. A misconfiguration of the range of the acoustic active layer entailed to slow down the ping rate (1.5-2.0 seconds) in relation to the standard values (at about 0.3 seconds), resulting an acoustic sampling rate much lower than it should be. Therefore, the results from this acoustic sampling and the resulting estimates from this survey should be considered with caution. Anchovy abundance and biomass were of 953 million fish and 10 493 t. The abundance and biomass of age-0 anchovies were estimated at 543 million fish and 3 834 t, 57% and 36% of the total population abundance and biomass, respectively. Despite the methodological problems, these estimates seem to suggest a recent decrease in relation to previous years. The estimates for Gulf of Cadiz sardine in the surveyed area were of 1 134 million fish and 20 679 t. Estimates of age-0 sardine were of 1 036 million fish and 15 224 t, 91% and 74% of the total estimated abundance and biomass, respectively. Even taking into account a possible underestimation for the abovementioned methodological problems, the values reached in 2018 were above the historical mean for the total population and recruits abundance and for the recruit biomass, and they might suggest a relatively stable situation since the maxima registered in 2016