329 research outputs found
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Accessing extremes of mid-latitudinal wave activity: methodology and application
A statistical methodology is proposed and tested for the analysis of extreme values of atmospheric wave activity at
mid-latitudes. The adopted methods are the classical block-maximum and peak over threshold, respectively based on
the generalized extreme value (GEV) distribution and the generalized Pareto distribution (GPD). Time-series of the
‘Wave Activity Index’ (WAI) and the ‘Baroclinic Activity Index’ (BAI) are computed from simulations of the General
Circulation Model ECHAM4.6, which is run under perpetual January conditions. Both the GEV and the GPD analyses
indicate that the extremes ofWAI and BAI areWeibull distributed, this corresponds to distributions with an upper bound.
However, a remarkably large variability is found in the tails of such distributions; distinct simulations carried out under
the same experimental setup provide sensibly different estimates of the 200-yr WAI return level. The consequences
of this phenomenon in applications of the methodology to climate change studies are discussed. The atmospheric
configurations characteristic of the maxima and minima of WAI and BAI are also examined
Flesh qualitative traits of tub gurnard (Chelidonichthys lucerna L.), a promising species candidate for aquaculture, captured in the middle Adriatic Sea in different seasons
The quality traits of the fillets from tub gurnard (Chelidonichthys lucerna L.) fished in the mid-Adriatic Sea were investigated. Forty fishes per season were sampled to evaluate the proximate composition, cholesterol content and fatty acid profile of fillets. Seasons significantly affected the quality traits of flesh. The protein content ranged from 19.39% in winter to 19.67% in summer, without significant differences. Lipid content was notably higher in spring (2.28%) and summer (2.32%), compared to autumn (1.72%) and winter (1.31%). Energy content was significantly higher in spring (416.45 kJ/100 g) and summer (417.97 kJ/100 g) compared to autumn (391.35 kJ/100 g) and winter (372.79 kJ/100 g). Saturated fatty acid content was highest in spring (35.88%), whereas monounsaturated acid content was not influenced by season. The n-3 polyunsaturated fatty acid content exceeded 37% of total fatty acid content during summer. The n-6/n-3 ratio remained favourably low across all seasons (from 0.16 to 0.18), with a slight significant increase in autumn (0.31). In conclusion, this study indicates that the flesh of tub gurnard has high nutritional value year-round, with the best results (in terms of n-3 polyunsaturated fatty acids) being obtained in summer
A supervisory sliding mode control approach for cooperative robotic system of systems
This paper deals with the formulation of a supervisory sliding mode (SM) control approach oriented to deal with the interesting class of system of systems of robotic nature. This class of systems is characterized by the fact of being inherently distributed, cooperative, and, possibly, heterogeneous. In this paper, we propose a modular and composable approach relying on basic modules featuring a multilevel functional architecture, including a supervisor and a couple of hybrid position/force control schemes associated with a couple of cooperative robotic manipulators. In principle, the overall robotic system we are referring to can be viewed as a collection of basic modules of that type. In this paper, we focus on the design of the basic module. The hybrid position/force control schemes therein included are based on position and force controllers. The proposed position and force controllers are of SM type, to assure suitable robustness to perform a satisfactory trajectory tracking even in presence of unavoidable modeling uncertainties and external disturbances. The verification and the validation of our proposal have been performed by simulating the supervisor and the hybrid control scheme applied to one of the two robotic manipulators while experimentally testing the position control on the other arm. The experimental part of the tests has been carried out on a COMAU SMART3-S2 anthropomorphic industrial robotic manipulator
Tub gurnard Chelidonichthys lucerna L.: a new fish species suitable for farming? First answers evaluating the growth of juveniles reared at different stocking densities, welfare and fillet quality
A trial was conducted to evaluate the growth performance and survival of Chelidonichthys lucerna. A total of 13 352 180-days old juveniles (5.5 ± 2 g; 5 ± 1 cm) were reared at two different densities (A-EXP = 68 fish m−3; B-FFA = 15 fish m−3) in eight tanks (four tanks per group) for 360 days. The welfare status and meat quality of fish were evaluated for the A-EXP and B-FFA groups in comparison with wild-caught fishery gurnard (C-WID). The survival rate was high for both A-EXP (79%) and B-FFA (93.5%). B-FFA fish had the highest specific growth rate (1.16 vs. 1.07; P < 0.05), and were heavier than A-EXP fish (321 ± 40 g vs .239 ± 44 g; P < 0.01). Rearing conditions did not affect blood metabolites, except for glucose concentrations, which were higher in C-WID (P < 0.05). The meat quality traits showed that reared groups were fatter (2.8–3.2%) than C-WID (0.94%); total n-3 fatty acids (19.02–19.26%) were lower in reared groups than C-WID (29.99%); and EPA + DHA were similar in all groups (15.1–16.61% vs. 27.99%). Despite the good growth and survival, the final mean weight was below that requested by the market (400–500 g). Future research efforts should focus on reducing the feed conversion rate (3:1)
Suitability of artisanal fishery discards as feed for juvenile tub gurnard (chelidonichthys lucerna L.) reared in sea bottom cages in the mid Adriatic Sea
The suitability of using discards from artisanal fisheries as feed for wild-caught Chelidonichthys lucerna (L.) reared in submerged cages in the Adriatic Sea was investigated. Three-hundred juvenile tub gurnard (72.9 ± 11 g, 18 ± 1 cm) were captured and separated into four circular 35.3 m3 submerged cages. Two stocking densities were used: two cages contained 60 fish each (1.7 fish m-3; CG-L) and two cages contained 90 fish each (2.55 fish m-3; CG-H). Growth performance and survival rates were recorded over a 240 day period during which tub gurnard were fed with a variety non-target fishery discards, including common crab, sardine, Atlantic chub mackerel, anchovy, and salema. The survival rate was approximately 90% in both groups (CG-L = 91% and CG-H = 90%), with final stocking densities of 0.32 kg m-3 and 0.49 kg m-3 for the CG-L and CG-H groups, respectively. There were no significant differences in final mean body weight or length between the CG-L group (206 ± 23 g, 24.6 ± 2 cm) and the CG-H group (215.5 ± 32 g, 24.8 ± 2 cm). The condition index was similar between the two groups (1.38 and 1.42 for CG-L and CG-H, respectively). The feed conversion ratio was high in both the CG-H (2.39) and CG-L (2.32) cages. These results demonstrate that viable growth rates of tub gurnard may be obtained by feeding recycled fishery discards and rearing in cages placed on the seabed, which allows for the natural benthic behavior of this species
Vascular-confined multi-passage discoidal nanoconstructs for the low-dose docetaxel inhibition of triple-negative breast cancer growth
AbstractTaxane efficacy in triple negative breast cancer (TNBC) is limited by insufficient tumor accumulation and severe off-target effects. Nanomedicines offer a unique opportunity to enhance the anti-cancer potency of this drug. Here, 1,000 nm × 400 nm discoidal polymeric nanoconstructs (DPN) encapsulating docetaxel (DTXL) and the near infrared compound lipid-Cy5 were engineered. DPN were obtained by filling multiple times cylindrical wells in a poly(vinyl alcohol) template with a polymer mixture comprising poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) diacrylate (PEG-DA) chains together with therapeutic and imaging agents. The resulting "multi-passage" DPN exhibited higher DTXL loading, lipid-Cy5 stability, and stiffness as compared to the conventional "single-passage" approach. Confocal microscopy confirmed that DTXL-DPN were not taken up by MDA-MB-231 cells but would rather sit next to the cell membrane and slowly release DTXL thereof. Empty DPN had no toxicity on TNBC cells, whereas DTXL-DPN presented a cytotoxic potential comparable to free DTXL (IC50 = 2.6 nM ± 1.0 nM vs. 7.0 nM ± 1.09 nM at 72 h). In orthotopic murine models, DPN accumulated in TNBC more efficiently than free-DTXL. With only 2 mg/kg DTXL, intravenously administered every 2 days for a total of 13 treatments, DTXL-DPN induced tumor regression and were associated to an overall 80% survival rate as opposed to a 30% survival rate for free-DTXL, at 120 days. All untreated mice succumbed before 90 days. Collectively, this data demonstrates that vascular confined multi-passage DPN, biomimicking the behavior of circulating platelets, can efficiently deliver chemotherapeutic molecules to malignant tissues and effectively treat orthotopic TNBC at minimal taxane doses
Effects of dietary supplementation with krill meal on pigmentation and quality of flesh of rainbow trout (Oncorhynchus mykiss)
Effects of administration of krill meal and synthetic astaxanthin during the finisher phase of the fattening cycle of rainbow trout on flesh pigmentation and quality traits were studied. The inclusion of krill meal increased the body weight and size and decreased the peri-visceral fat and visceral weight indices. The astaxanthin diet produced the highest accumulation of total carotenoids in the fillet compared to the krill meal diet: the difference was significant after 15 days of feeding (2.50 vs 2.10 mg/kg) till the end of the trial (5.00 vs 4.80 mg/kg). The same pattern was observed for astaxanthin concentration with the highest values in the fillets of fish fed the astaxanthin diet. Fillet lightness (L*) was not affected by trout diets whereas redness (a*) and yellowness (b*) were significantly higher in fish fed the astaxanthin diet until day 30 of the trial. Hue was not affected by feeding, whereas chroma was significantly higher in the fish fed astaxanthin throughout the trial except on day 45 of sampling. Trout fed the krill meal diet had a paler pink-red colour on the SalmoFan scale than those receiving the astaxanthin diet. No significant differences emerged in proximate composition and cholesterol content of trout in the two groups. The fatty acid profile of the fillets reflected the fatty acids of the diets administered to the trout: eicosapentaenoic, docosahexaenoic and docosapentaenoic acids and total n-3 polyunsaturated fatty acids were significantly higher in the fish fed the krill meal
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