Eigenvalue Placement and Stabilization by Constrained Optimization

A pole placement algorithm is proposed which uses constrained nonlinear optimization techniques on a finite dimensional model of a linear n degree of freedom system. Low order feedback control is assumed where r poles may be assigned; r being the rank of the sensor coefficient matrix. It is shown that by combining feedback control theory methods with optimization techniques, one can ensure the stability characteristics of a system, and can alter its transient response

Qawl qarrieqi?

L-awtur jagħti tagħrif etimoloġiku dwar il-qawl Malti: “Santa Luċija u l-jum jitwal pass ta’ tarbija.”N/

Analysis of Aeroheating Augmentation due to Reaction Control System Jets on Orion Crew Exploration Vehicle

The analysis of effects of the reaction control system jet plumes on aftbody heating of Orion entry capsule is presented. The analysis covered hypersonic continuum part of the entry trajectory. Aerothermal environments at flight conditions were evaluated using Langley Aerothermal Upwind Relaxation Algorithm (LAURA) code and Data Parallel Line Relaxation (DPLR) algorithm code. Results show a marked augmentation of aftbody heating due to roll, yaw and aft pitch thrusters. No significant augmentation is expected due to forward pitch thrusters. Of the conditions surveyed the maximum heat rate on the aftshell is expected when firing a pair of roll thrusters at a maximum deceleration condition

The knotty biology of canine coronavirus: a worrying model of coronaviruses’ danger.

Severe clinical diseases associated to αCoronavirus (αCoV) infections were recently demonstrated for the first time in humans and a closely related but distinct canine CoV (CCoV) variant was identified in the nasopharyngeal swabs of children with pneumonia hospitalized in Malaysia, in 2017–2018. The complete genome sequence analysis demonstrated that the isolated strain, CCoV-HuPn-2018, was a novel canine-feline-like recombinant virus with a unique nucleoprotein. The occurrence of three human epidemics/pandemic caused by CoVs in the recent years and the detection of CCoV-HuPn-2018, raises questions about the ability of these viruses to overcome species barriers from their reservoirs jumping to humans. Interestingly, in this perspective, it is interesting to consider the report concerning new CCoV strains with a potential dual recombinant origin through partial S-gene exchange with porcine transmissible gastroenteritis virus (TGEV) identified in pups died with acute gastroenteritis in 2009. The significance of the ability of CCoVs to evolve is still unclear, but several questions arisen on the biology of these viruses, focusing important epidemiological outcomes in the field, in terms of both virus evolution and prophylaxis. The new CCoV-Hupn-2018 should lead researchers to pay more attention to the mechanisms of recombination among CoVs, rather than to the onset of variants as a result of mutations, suggesting a continuous monitoring of these viruses and in particular of SARS-CoV-

One world, one health, one virology of the mysterious labyrinth of Coronaviruses: the canine coronavirus affair

The described pictures underline the ability of CoVs of driving genetic evolution, to undergoes recombination, and to easy cross interspecies barriers. This potential high genetic recombination ability ensures the proliferation of new strains that may have selective advantages over parental genomes.9 In this aspect, the newly identified CCoV-Hupn-2018 should lead researchers to pay a special attention to the mechanisms of recombination among CoVs, in addition to the onset of variants as a result of mutations. Continuous monitoring of these viruses are required because (without saying as Cassandra…!!!) recombination observed in CCoVs may represent a dramatic warning for SARS-CoV-2

Evaluation of virucidal activity of fabrics using feline coronavirus

Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2) is an enveloped RNA virus responsible for the 2019 coronavirus disease (COVID-19) that represents a global health threat, causing an ongoing pandemic in many countries and territories. WHO recommendations emphasize the importance of all personal protective equipment (PPE) that can interrupt COVID-19 transmission. The textile industry and scientists are developing hygienic fabrics by the addition of or treatment with various antimicrobial and antiviral compounds. Methods for determining the antiviral activity of fabrics are reported in the International Standards Organization (ISO) 18184 (2019) guidelines. Three different fabric samples treated with silver derivate, copper derivative and a not treated cotton fabric used as control were examined and put in contact with a suspension of feline coronavirus (FCoV). After 2 h of incubation a significant decrease of viral titer, as high as 3.25 log10 Tissue Culture Infectious Dose (TCID)50/50 μl, in feline cells was observed in treated fabrics, with respect to not treated fabrics. In this study, we optimized laboratory methods to evaluate the virucidal activity of silver- and copper treated cotton- based fabrics against coronavirus, using FCoV suitable as a surrogate of SARS-CoV-2 but safe for laboratory technicians

Survival of a sars-cov-2 surrogate on flow-pack polyethylene and polystyrene food trays at refrigeration and room temperature conditions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the current pandemic referred to as coronavirus disease 2019, is spread by direct and indirect transmission between humans, including contact with contaminated surfaces, frozen food, packaging materials, and storage environments. Food contamination may occur in the “farm-to-table” lifecycle through contact with food handlers and environments. In the present study, the survival of a SARS-CoV-2 surrogate (feline coronavirus (FCoV)) at room temperature and refrigeration conditions for different time intervals on two types packaging widely used packaging, namely flow-pack polyethylene and polystyrene food trays, was investigated. FCoV was stable on the flow-pack polyethylene for 48 h and 120 h at room temperature and 4◦C, respectively, while it persisted on polystyrene food trays for 36 h at room temperature and for 120 h at +4◦C. The results of our study highlight the possible implications of food packaging in the spread of SARS-CoV-2 during the current pandemic

Systematic pathologic findings report of callosciurus finlaysonii (Horsfield, 1823) (rodentia, sciuridae) squirrels from maratea area (south italy) to investigate species-specific pathologies, reliability of co2 euthanasia method, and possible use as environmental sentinels

The aim of the present study was to macroscopically and microscopically describe the main pathological findings occurring in this invasive species, in order to better understand the real risks for naïve animals and humans. The present study was conducted on Callosciurusfinlaysonii squirrels (n = 165), captured in the Maratea area and euthanatized with CO2 according to a population control of invasive species of the Italian Agriculture Ministry project (ex CIPE project) and conferred to the Department of Veterinary Medicine of Bari (Italy). Macroscopic analysis demonstrated heart, lung, and liver congestion, probably due to the euthanasia method, and variable lesions of bowel, liver, and kidney. The microscopically examination showed the presence of lymphocytic infiltration in the lower layers of the bowel, suggesting enteritis. To the best of our knowledge, this is the first systemic report of gross and microscopical anatomopathological lesions in C.finlaysonii, in South Italy. The results could be useful to fill a gap of knowledge of this species in Italy

Thermal ionization of excitons in V-shaped quantum wires

The exciton-to-free-carrier transition in GaAs and In_xGa_{1-x}As V-shaped quantum wires is revealed by means of temperature-dependent magnetoluminescence experiments. The experimental results are in excellent agreement with the diamagnetic shift obtained from a solution of the full two-dimensional Schrödinger equation for electrons and holes including magnetic-field and excitonic effects. In the GaAs wires, the exciton-to-free-carrier transition is found to occur at temperature consistent with the exciton binding energies. In the In_xGa_{1-x}As wires the diamagnetic shift of the luminescence is found to be free-carrier-like, independent of temperature, due to the weakening of the exciton binding energy induced by the internal piezoelectric field