986 resultados para Stable negative electrode


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study examines the relationship between dividend yield and stock return over bullish and bearish Finnish stock market by testing for alpha and beta shifts across bull and bear markets. In addition, this study examines if various factors, such as a standard deviation of dividends, firm size and profitability have an effect on the size, of the firms’ dividends and systematic risk of the stocks. We divide stocks into five portfolios on the basis of their past average dividend yields and investigate if the highest yielding portfolios outperform the lowest yielding portfolios during the different market conditions. As a result, high yielding stocks were most stable during the examination period and offered downside protection on bear markets. However, a strategy of forming portfolios with past dividend yields led to negative alphas even in bull markets. Standard deviation of dividends, firm size and profitability were found to have no effect on the size of dividends and systematic risk of the stocks.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Alzheimer`s disease (AD) is characterised neuropathologically by the presence of extracellular amyloid plaques, intraneuronal neurofibrillary tangles, and cerebral neuronal loss. The pathological changes in AD are believed to start even decades before clinical symptoms are detectable. AD gradually affects episodic memory, cognition, behaviour and the ability to perform everyday activities. Mild cognitive impairment (MCI) represents a transitional state between normal aging and dementia disorders, especially AD. The predictive accuracy of the current and commonly used MCI criteria devide this disorder into amnestic (aMCI) and non-amnestic (naMCI) MCI. It seems that many individuals with aMCI tend to convert to AD. However many MCI individuals will remain stable and some may even recover. At present, the principal drugs for the treatment of AD provide only symptomatic and palliative benefits. Safe and effective mechanism-based therapies are needed for this devastating neurodegenerative disease of later life. In conjunction with the development of new therapeutic drugs, tools for early detection of AD would be important. In future one of the challenges will be to detect at an early stage these MCI individuals who will convert to AD. Methods which can predict which MCI subjects will convert to AD will be much more important if the new drug candidates prove to have disease-arresting or even disease–slowing effects. These types of drugs are likely to have the best efficacy if administered in the early or even in the presymptomatic phase of the disease when the synaptic and neuronal loss has not become too widespread. There is no clinical method to determine with certainly which MCI individuals will progress to AD. However there are several methods which have been suggested as predictors of conversion to AD, e.g. increased [11C] PIB uptake, hippocampal atrophy in MRI, low CSF A beta 42 level, high CSF tau-protein level, apolipoprotein E (APOE) ε4 allele and impairment in episodic memory and executive functions. In the present study subjects with MCI appear to have significantly higher [11C] PIB uptake vs healthy elderly in several brain areas including frontal cortex, the posterior cingulate, the parietal and lateral temporal cortices, putamen and caudate. Also results from this PET study indicate that over time, MCI subjects who display increased [11C] PIB uptake appear to be significantly more likely to convert to AD than MCI subjects with negative [11C] PIB retention. Also hippocampal atrophy seems to increase in MCI individuals clearly during the conversion to AD. In this study [11C] PIB uptake increases early and changes relatively little during the AD process whereas there is progressive hippocampal atrophy during the disease. In addition to increased [11C] PIB retention and hippocampal atrophy, the status of APOE ε4 allele might contribute to the conversion from MCI to AD.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Evolution of Bordetella pertussis post vaccination Whooping cough or pertussis is caused by the gram-negative bacterium Bordetella pertussis. It is a highly contiguous disease in the human respiratory tract. Characteristic of pertussis is a paroxysmal cough with whooping sound during gasps of breath after coughing episodes. It is potentially fatal to unvaccinated infants. The best approach to fight pertussis is to vaccinate. Vaccinations against pertussis have been available from the 1940s. Traditionally vaccines were whole-cell pertussis (wP) preparations as part of the combined diphtheria-tetanus-pertussis (DTP) vaccines. More recently acellular pertussis (aP) vaccines have replaced the wP vaccines in many countries. The aP vaccines are less reactogenic and can also be administered to school children and adults. There are several publications reporting variation in the i>B. pertussis virulence factors that are also aP vaccine antigens. This has occurred in the genes coding for pertussis toxin and pertactin about 15 to 30 years after the introduction of pertussis vaccines to immunisation programs. Resurgence of pertussis has also been reported in many countries with high vaccination coverage. In this study the evolution of B. pertussis was investigated in Finland, the United Kingdom, Poland, Serbia, China, Senegal and Kenya. These represent countries with a long history of high vaccination coverage with stable vaccines or changes in the vaccine formulation; countries which established high vaccination coverage late; and countries where vaccinations against pertussis were started late. With bacterial cytotoxicity and cytokine measurements, comparative genomic hybridisation, pulsed-field gel electrophoresis (PFGE), genotyping and serotyping it was found that changes in the vaccine composition can postpone the emergence of antigenic variants. It seems that the change in PFGE profiles and the loss of genetic material in the genome of B. pertussis are similar in most countries and the vaccine-induced immunity is selecting non-vaccine type strains. However, the differences in the formulation of the vaccines, the vaccination programs and in the coverage of pertussis vaccination have affected the speed and timing of these changes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite the use of laparoscopy in abdominal trauma for several decades, it was only after the advent of video chip camera that an explosion of interest ocurred, giving rise to possibilities and perspectives not only in diagnosis but also in therapeutics. In trauma, its use has been gradually defined and experience has shown the benefits of the method in early diagnosis of visceral injuries as well as avoiding unnecessary laparotomies. Trauma laparoscopy is a safe method, can reduce negative and nontherapeutic laparotomies. The worrisome failure of laparoscopy to detect gastrintestinal injuries, specially small bowel lesions can be avoided with a mandatory and apropriated "run bowel" exploration. We believe that in hemodinamically stable patients, video laparoscopy is safely indicated in some situations in trauma, such as evaluation of diaphragmatic injuries in thoraco abdominal stab wounds and tangential gunshot wounds of anterior abdominal wall.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Inhimilliseen turvallisuuteen kriisinhallinnan kautta – oppimisen mahdollisuuksia ja haasteita Kylmän sodan jälkeen aseelliset konfliktit ovat yleensä alkaneet niin sanotuissa hauraissa valtioissa ja köyhissä maissa, ne ovat olleet valtioiden sisäisiä ja niihin on osallistunut ei-valtiollisia aseellisia ryhmittymiä. Usein ne johtavat konfliktikierteeseen, jossa sota ja vakaammat olot vaihtelevat. Koska kuolleisuus konflikteissa voi jäädä alle kansainvälisen määritelmän (1000 kuollutta vuodessa), kutsun tällaisia konflikteja ”uusiksi konflikteiksi”. Kansainvälinen yhteisö on pyrkinyt kehittämään kriisinhallinnan ja rauhanrakentamisen malleja, jotta pysyvä rauhantila saataisiin aikaiseksi. Inhimillinen turvallisuus perustuu näkemykseen, jossa kunnioitetaan jokaisen yksilön ihmisoikeuksia ja jolla on vaikutusta myös kriisinhallinnan ja rauhanrakentamisen toteuttamiseen. Tutkimukseen kuuluu kaksi empiiristä osaa: Delfoi tulevaisuuspaneeliprosessin sekä kriisinhallintahenkilöstön haastattelut. Viisitoista eri alojen kriisinhallinta-asiantuntijaa osallistui paneeliin, joka toteutettiin vuonna 2008. Paneelin tulosten mukaan tulevat konfliktit usein ovat uusien konfliktien kaltaisia. Lisäksi kriisinhallintahenkilöstöltä edellytetään vuorovaikutus- ja kommunikaatiokykyä ja luonnollisesti myös varsinaisia ammatillisia valmiuksia. Tulevaisuuspaneeli korosti vuorovaikutus- ja kommunikaatiotaitoja erityisesti siviilikriisinhallintahenkilöstön kompetensseissa, mutta samat taidot painottuivat sotilaallisen kriisinhallinnan henkilöstön kompetensseissakin. Kriisinhallinnassa tarvitaan myös selvää työnjakoa eri toimijoiden kesken. Kosovossa työskennelleen henkilöstön haastatteluaineisto koostui yhteensä 27 teemahaastattelusta. Haastateltavista 9 oli ammattiupseeria, 10 reservistä rekrytoitua rauhanturvaajaa ja 8 siviilikriisinhallinnassa työskennellyttä henkilöä. Haastattelut toteutettiin helmi- ja kesäkuun välisenä aikana vuonna 2008. Haastattelutuloksissa korostui vuorovaikutus- ja kommunikaatiotaitojen merkitys, sillä monissa käytännön tilanteissa haastateltavat olivat ratkoneet ongelmia yhteistyössä muun kriisinhallintahenkilöstön tai paikallisten asukkaiden kanssa. Kriisinhallinnassa toteutui oppimisprosesseja, jotka usein olivat luonteeltaan myönteisiä ja informaalisia. Tällaisten onnistumisten vaikutus yksilön minäkuvaan oli myönteinen. Tällaisia prosesseja voidaan kuvata ”itseä koskeviksi oivalluksiksi”. Kriisinhallintatehtävissä oppimisella on erityinen merkitys, jos halutaan kehittää toimintoja inhimillisen turvallisuuden edistämiseksi. Siksi on tärkeää, että kriisinhallintakoulutusta ja kriisinhallintatyössä oppimista kehitetään ottamaan huomioon oppimisen eri tasot ja ulottuvuudet sekä niiden merkitys. Informaaliset oppimisen muodot olisi otettava paremmin huomioon kriisinhallintakoulutusta ja kriisinhallintatehtävissä oppimista kehitettäessä. Palautejärjestelmää olisi kehitettävä eri tavoin. Koko kriisinhallintaoperaation on saatava tarvittaessa myös kriittistä palautetta onnistumisista ja epäonnistumisista. Monet kriisinhallinnassa työskennelleet kaipaavat kunnollista palautetta työrupeamastaan. Liian rutiininomaiseksi koettu palaute ei edistä yksilön oppimista. Spontaanisti monet haastatellut pitivät tärkeänä, että kriisinhallinnassa työskennelleillä olisi mahdollisuus debriefing- tyyppiseen kotiinpaluukeskusteluun. Pelkkä tällainen mahdollisuus ilmeisesti voisi olla monelle myönteinen uutinen, vaikka tilaisuutta ei hyödynnettäisikään. Paluu kriisinhallintatehtävistä Suomeen on monelle haasteellisempaa kuin näissä tehtävissä työskentelyn aloittaminen ulkomailla. Tutkimuksen tulokset kannustavat tutkimaan kriisinhallintaa oppimisen näkökulmasta. On myös olennaista, että kriisinhallinnan palautejärjestelmiä kehitetään mahdollisimman hyvin edistämään sekä yksilöllistä että organisatorista oppimista kriisinhallinnassa. Kriisinhallintaoperaatio on oppimisympäristö. Kriisinhallintahenkilöstön kommunikaatio- ja vuorovaikutustaitojen kehittäminen on olennaista tavoiteltaessa kestävää rauhanprosessia, jossa konfliktialueen asukkaatkin ovat mukana.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine virus.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bovine herpesvirus type 5 (BoHV-5) is a major cause of viral meningoencephalitis in cattle. The expression of different viral proteins has been associated with BoHV-5 neuropathogenesis. Among these, gI, gE and US9 have been considered essential for the production of neurological disease in infected animals. To evaluate the role of gI, gE and US9 in neurovirulence, a recombinant from which the respective genes were deleted (BoHV-5 gI-/gE-/US9-) was constructed and inoculated in rabbits of two age groups (four and eight weeks-old). When the recombinant virus was inoculated through the paranasal sinuses of four weeks-old rabbits, neurological disease was observed and death was the outcome in 4 out of 13 (30.7 %) animals, whereas clinical signs and death were observed in 11/13 (84.6%) of rabbits infected with the parental virus. In eight weeks-old rabbits, the BoHV-5 gI-/gE-/US9- did not induce clinically apparent disease and could not be reactivated after dexamethasone administration, whereas wild type BoHV-5 caused disease in 55.5% of the animals and was reactivated. These findings reveal that the simultaneous deletion of gI, gE and US9 genes did reduce but did not completely abolish the neurovirulence of BoHV-5 in rabbits, indicating that other viral genes may also play a role in the induction of neurological disease.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mutant viral strains deleted in non-essential genes represent useful tools to study the function of specific gene products in the biology of the virus. We herein describe an investigation on the phenotype of a bovine herpesvirus 5 (BoHV-5) recombinant deleted in the gene encoding the enzyme thymidine kinase (TK) in rabbits, with special emphasis to neuroinvasiveness and the ability to establish and reactivate latent infection. Rabbits inoculated with the parental virus (SV-507/99) (n=18) at a low titer (10(5.5)TCID50) shed virus in nasal secretions in titers up to 10(4.5)TCID50 for up to 12 days (average: 9.8 days [5-12]) and 5/ 16 developed neurological disease and were euthanized in extremis. Rabbits inoculated with the recombinant BoHV-5TKΔ at a high dose (10(7.1)TCID50) also shed virus in nasal secretions, yet to lower titers (maximum: 10(2.3)TCID50) and for a shorter period (average: 6.6 days [2-11]) and remained healthy. PCR examination of brain sections of inoculated rabbits at day 6 post-infection (pi) revealed a widespread distribution of the parental virus, whereas DNA of the recombinant BoHV-5TKΔ-was detected only in the trigeminal ganglia [TG] and olfactory bulbs [OB]. Nevertheless, during latent infection (52pi), DNA of the recombinant virus was detected in the TGs, OBs and also in other areas of the brain, demonstrating the ability of the virus to invade the brain. Dexamethasone (Dx) administration at day 65 pi was followed by virus reactivation and shedding by 5/8 rabbits inoculated with the parental strain (mean duration of 4.2 days [1 - 9]) and by none of seven rabbits inoculated with the recombinant virus. Again, PCR examination at day 30 post-Dx treatment revealed the presence of latent DNA in the TGs, OBs and in other areas of the brain of both groups. Taken together, these results confirm that the recombinant BoHV-5TKΔ is highly attenuated for rabbits. It shows a reduced ability to replicate in the nose but retains the ability to invade the brain and to establish latent infection. Additional studies are underway to determine the biological and molecular mechanisms underlying the inability of BoHV-5TKΔ to reactivate from latency.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In early lactation dairy cattle suffer metabolic alterations caused by negative energy balance, which predisposes to fatty liver and ketosis. The aim of this study was to evaluate the metabolic condition of high yielding dairy cows subjected to three treatments for preventing severe lipomobilization and ketosis in early lactation. Fifty four multiparous Holstein cows yielding >30 L/day were divided into four groups: control (CN= no treatment), glucose precursor (PG= propylene-glycol), hepatic protector (Mp= Mercepton®), and energy supplement with salts of linolenic and linoleic faty acids (Mg-E= Megalac-E®). Treatments were administrated randomly at moment of calving until 8 weeks postpartum. Blood samples were collected on days 1, 7, 14, 21, 28, 35, 42 and 49 postpartum. Body condition score (BCS) was evaluated at the same periods and milk yield was recorded at 2nd, 4th, 5th, 6th, 7th, and 8th weeks of lactation. Concentrations of non-esterified fatty acids (NEFA), albumin, AST, ß-hydroxybutyrate (BHBA), cholesterol, glucose, total protein, urea and triglycerides were analyzed in blood samples. Cut-off points for subclinical ketosis were defined when BHBA >1.4 mmol/L and NEFA >0.7 mmol/L. General occurrence of subclinical ketosis was 24% during the period. An ascendant curve of cholesterol and glucose was observed from the 1st to the 8th week of lactation, while any tendency was observed with BHBA and NEFA, although differences among treatments were detected (p<0.05). BCS decreased from a mean of 3.85 at 1st week to 2.53 at 8th week of lactation (p=0.001). Milk yield was higher in the Mg-E group compared with the other treatment groups (p<0.05) Compared with the CN group, the treatments with Mp and PG did not show significant differences in blood biochemistry and milk yield. Cows receiving PG and Mg-E showed higher values of BHBA and NEFA (P<0.05), indicating accentuated lipomobilization. Supplementation with Mg-E also resulted in significant higher concentrations of cholesterol, BHBA, urea, AST and lower values of glycemia. This performance may be explained by the highest milk yield observed with this treatment. Treatments with PG and Mp did not improve milk yield, compared with control cows, but did not show metabolic evidence of ketosis, fat mobilization or fatty liver. These results suggest that treatment with Mg-E improves milk production but induces a higher negative energy balance leading to moderated lipomobilization and ketone bodies production, increasing the risk of fatty liver.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present study evaluated the pheno- and genotypical antimicrobial resistance profile of coagulase-negative Staphylococcus (CNS) species isolated from dairy cows milk, specially concerning to oxacillin. Of 100 CNS isolates, the S. xylosus was the prevalent species, followed by S. cohnii, S. hominis, S. capitis and S. haemolyticus. Only 6% were phenotypically susceptible to the antimicrobial agents tested in disk diffusion assay. Penicillin and ampicillin resistance rates were significantly higher than others antimicrobials. Four isolates were positive to mecA gene (4%), all represented by the S. xylosus species. The blaZ gene was detected in 16% of the isolates (16/100). It was noticed that all mecA + were also positive to this gene and the presence of both genes was correlated to phenotypic beta-lactamic resistance. We conclude that CNS species from bovine milk presented significantly distinct antimicrobial resistance profiles, evaluated by phenotypic and genotypic tests, which has implications for treatment and management decisions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology and ecology of the stable fly, including larval habitats and their reproduction sites is extremely important for further development of control programs. This paper aims to report the occurrence and development of S. calcitrans larvae inside sugarcane stems in three municipalities of Mato Grosso do Sul. The sugarcane stems give protection against bad weather conditions and insecticide application. In this way, for sustainable sugarcane growth specific research concerning this situation should be conducted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objectives of the study were to evaluate the presence/production of beta-lactamases by both phenotypic and genotypic methods, verify whether results are dependent of bacteria type (Staphylococcus aureus versus coagulase-negative Staphylococcus - CNS) and verify the agreement between tests. A total of 200 bacteria samples from 21 different herds were enrolled, being 100 CNS and 100 S. aureus. Beta-lactamase presence/detection was performed by different tests (PCR, clover leaf test - CLT, Nitrocefin disk, and in vitro resistance to penicillin). Results of all tests were not dependent of bacteria type (CNS or S. aureus). Several S. aureus beta-lactamase producing isolates were from the same herd. Phenotypic tests excluding in vitro resistance to penicillin showed a strong association measured by the kappa coefficient for both bacteria species. Nitrocefin and CLT are more reliable tests for detecting beta-lactamase production in staphylococci.