ABC and Hamiltonian Monte-Carlo methods in COGARCH models

The analysis of financial series, assuming calendar effects and unequally spaced times over continuous time, can be studied by means of COGARCH models based on Lévy processes. In order to estimate the COGARCH model parameters, we propose to use two different Bayesian approaches. First, we suggest to use a Hamiltonian Montecarlo (HMC) algorithm that improves the performance of standard MCMC methods. Secondly, we introduce an Approximate Bayesian Computational (ABC) methodology which allows to work with analytically infeasible or computationally expensive likelihoods. After a simulation and comparison study for both methods, HMC and ABC, we apply them to model the behaviour of some NASDAQ time series and we discuss the results

Length Distributions and Recruitment Index of Northern Shrimp (Pandalus borealis) in Flemish Cap (Division 3M) in 1993-1998, as Inferred from Stomach Contents Analysis of Cod (Gadus morhua), Greenland halibut (Reinhardtius hippoglossoides) and Thorny Skate (Raja radiata)

From stomachs of cod (Gadus morhua), Greenland halibut (Reinhardtius hippoglossoides) and thorny skate (Raja radiata) sampled in the fishing surveys carried out in Flemish Cap in July from 1993 to 1998, the importance in diet, predator-prey relationship and length frequency of northern shrimp (Pandalus borealis) were evaluated. These three species prey on different lengths of northern shrimp as a function of their feeding habits and the overlap in their ranges of vertical distribution with that of their prey. The ability of these predators to sample different sizes of northern shrimp allows the observation of the annual progression of strong year classes of this prey and the estimate of its recruitment at age 2 from its frequency of occurrence in cod stomach contents from 1989 to 1997

Feeding of Greenland Halibut (Reinhardtius hippoglossoides) in 3LMNO NAFO Regulatory Area Divisions (Northwest Atlantic), 1991-94

Feeding of Greenland halibut in Flemish Pass and Newfoundland's Grand Bank slope (3LMNO NAFO divisions) was studied from on board commercial fleet analysis, from June 1991 to December 1994. Percentage of empty stomachs from 625 165 specimens and frequency of occurrence of prey from 18 527 stomachs, were used to evaluate feeding intensity and importance of prey groups. Examinationrevealed increasing feeding intensity with sin. The emptiness percentage varies with depth, in a directly proportional way, in specimens of less than 60 cm, and is inversely proportional in those of over 70 cm. A smaller percentage of empty stomachs was found in females than in males, upwards of the length of first maturity of the latter, as well as a decreasing feeding rate as females become reproductively active. Analysis of frequency of occurrence of main prey groups indicated a change in Greenland halibut feeding at 60 cm in all divisions, a change which supposes a fall in consumption of 0161w:elms and molluscs, an increase in fish and (fiat and an increase in prey species size. the difference between divisions is due to the consumption of Mallows yillosus by specimens of less than 60 cm in divisions 3NO : There are also significant changes with depth of around 1000 m in the diet of Reinhard/ins hippoglossoides of less than 60 cm, bringing about a substitution of capelin for decapod cephalopods At great depths squid have a similar role in the diet of Greenland halibut to that played by capelin on the continental shell The variation of the prey species is related to their disnibution. Offal arc an extra provision of food introduced by fishing activity, making up the second most important prey group in specimens of over 60 cm

Feeding Patterns of Greenland halibut (Reinhardtius hippoglossoides) in Flemish Pass (Northwest Atlantic)

A qualitative study of the food composition of Greenland halibut (Reinhardtius hippoglossoides) was made by on-board analysis of commercially caught fish in 1992. The fish were caught east of Newfoundland (NAFO Div. 3LM) in unusually deep waters, with an average of 1 040 m. Variations in feeding according to predator size, depth and month were studied. The annual average percentage of empty stomachs was 69%, increasing through the year for specimens over 60 cm. The frequency of occurrence (FO) of food items was used to evaluate the importance of prey groups. Fish (39%), cephalopods (32%) and decapod crustaceans (22%) were the main items, with cannibalism reaching 2%. An abrupt change in diet composition occurred in fish between 60 and 69 cm, from feeding on decapod crustaceans and cephalopods to fish and factory ship discarded offal. The influence of the fishery itself on the diet of Greenland halibut was observed when an important food component in the largest specimens (>60 cm) consisted of offal discarded after fish processing. This study indicates that the FO of the main prey groups bears more relation to the size of fish than with depth

Physical activity in centenarians beyond cut-point-based accelerometer metrics

This study described and compared physical activity (PA) characteristics at the end of the human lifespan using conventional cut-point-based versus cut-point-free accelerometer metrics. Eighteen institutionalized centenarians (101.5 ± 2.1 years, 72.2% female, 89% frail) wore the wrist GENEActiv accelerometer for 7 days. Conventional metrics, such as time spent in light-intensity PA (LiPA) and moderate-to-vigorous intensity PA (MVPA) were calculated according to published cut-points for adults and older adults. The following cut-point-free metrics were evaluated: average acceleration, intensity gradient and Mx metrics. Depending on the cut-point, centenarians accumulated a median of 15–132 min/day of LiPA and 3–15 min/day of MVPA. The average acceleration was 9.2 mg [Q1: 6.7 mg–Q3: 12.6 mg] and the intensity gradient was −3.19 [−3.34–−3.12]. The distribution of Z-values revealed positive skew for MVPA, indicating a potential floor effect, whereas the skew magnitude was attenuated for cut-point-free metrics such as intensity gradient or M5. However, both cut-point-based and cut-point-free metrics were similarly positively associated with functional independence, cognitive and physical capacities. This is the first time that PA has been described in centenarians using cut-point-free metrics. Our results suggest that new analytical approaches could overcome cut-point limitations when studying the oldest-old. Future studies using these new cut-point-free PA metrics are warranted to provide more complete and comparable information across groups and populations

Performance of Dual-Purpose Cows on a Native Pasture-\u3ci\u3eArachis pintoi\u3c/i\u3e Association in the Humid Tropics of Mexico

Native grasslands (NG) are the main feed supply of dual-purpose (DP) cows of the Mexican humid tropics. NG comprise about 85% of Paspalum, Axonopus and Cynodon species, about 5% of native legumes, mainly of Desmodium, and the remaining 10% are narrow and broad leafed weeds. Arachis pintoi (AP) is a persistent grazing tolerant tropical legume. In association with sown grasses, it has improved dry matter (DM) yield, nutritive quality of forage, and milk yield up to 9 kg/cow/day (González et al., 1996). The objective was to determine if productive performance of DP cows could be improved by the introduction of AP into NG grassland

Linezolid therapy for infective endocarditis

AbstractLinezolid is not yet recognised as a standard therapy for infective endocarditis. This report describes nine patients with endocarditis treated with linezolid and 33 similar cases from the medical literature. The majority of cases involved multiresistant strains, and the reasons for administering linezolid were refractory disease (60%), intolerance (28%), sequential therapy (12%) and a resistant pathogen (1%). Linezolid was administered for a mean of 37 days, with a successful outcome in 79% of cases. Reversible adverse effects were described in ten cases. The mean follow-up period was 8.5 months. Further data from randomised controlled clinical trials are needed to determine the efficacy and safety of linezolid for treating endocarditis

Feeding of Most Abundant Fish Species in Flemish Cap in Summer 1993

The stomach contents of 4320 fishes comprising 14 species were collected from Flemish Cap Bank (NW Newfoundland) at depths ranging from 130 to 730 m, during summer 1993. The general feeding intensity was high in all species. Three main feeding patterns were evident: the genus Sebastes consume primarily pelagic species, although they also feed on preys which migrate vertically such as shrimps, Euphausids and mysids. The benthic group is made up of American plaice (Hippoglossoides platessoides), witch flounder (Glyptocephalus cygnoglossus), arctic eelpout (Lycodes reticulatus), wolffishes (Anarhichas lupus and Anarhichas minor) and thorny skate (Raja radiata). Lastly, the group of benthopelagic fish remains, longf in hake (Urophycis chesteri), cod (Gadus morhua), grenadiers (Nezumia bairdi and Macrourus berglax) and Greenland halibut (Reinhardtius hippoglossoides). Pelagic and benthopelagic preys are an important food resource for all fish considered, the abundance of Hyperids, P. borealis and Sebastes sp. in summer makes them an important food resource in the diet of fish in Flemish Cap