2,329 research outputs found
An IT service management literature review: Challenges, benefits, opportunities and implementation practices
Information technology (IT) service management is considered a collection of frameworks that support organizations managing services. The implementation of these kinds of frameworks is constantly increasing in the IT service provider domain. The main objective is to define and manage IT services through its life cycle. However, from observing the literature, scarcely any research exists describing the main concepts of ITSM. Many organizations still struggle in several contexts in this domain, mainly during implementation. This research aims to develop a reference study detailing the main concepts related with ITSM. Thus, a systematic literature review is performed. In total, 47 articles were selected from top journals and conferences. The benefits, challenges, opportunities, and practices for ITSM implementation were extracted, critically analysed, and then discussed.info:eu-repo/semantics/publishedVersio
A Role for Both Conformational Selection and Induced Fit in Ligand Binding by the LAO Protein
Molecular recognition is determined by the structure and dynamics of both a protein and its ligand, but it is difficult to directly assess the role of each of these players. In this study, we use Markov State Models (MSMs) built from atomistic simulations to elucidate the mechanism by which the Lysine-, Arginine-, Ornithine-binding (LAO) protein binds to its ligand. We show that our model can predict the bound state, binding free energy, and association rate with reasonable accuracy and then use the model to dissect the binding mechanism. In the past, this binding event has often been assumed to occur via an induced fit mechanism because the protein's binding site is completely closed in the bound state, making it impossible for the ligand to enter the binding site after the protein has adopted the closed conformation. More complex mechanisms have also been hypothesized, but these have remained controversial. Here, we are able to directly observe roles for both the conformational selection and induced fit mechanisms in LAO binding. First, the LAO protein tends to form a partially closed encounter complex via conformational selection (that is, the apo protein can sample this state), though the induced fit mechanism can also play a role here. Then, interactions with the ligand can induce a transition to the bound state. Based on these results, we propose that MSMs built from atomistic simulations may be a powerful way of dissecting ligand-binding mechanisms and may eventually facilitate a deeper understanding of allostery as well as the prediction of new protein-ligand interactions, an important step in drug discovery
Toxicity of neem oil to the cassava green mite Mononychellus tanajoa (Bondar) (Acari: Tetranychidae)
O artigo não contém o resumo português.Neem (Azadirachta indica A. Juss.)-derived pesticides have been used against a wide range of agricultural pests including
tetranychid mites. Approaches combining lethal and sublethal toxicity studies of neem pesticides towards tetranychid mites
are necessary to a comprehensive evaluation of such products. Here, we evaluated the lethal and sublethal toxicity of the
neem oil Bioneem to the cassava green mite Mononychellus tanajoa (Bondar) by integrating lethal concentration (LC) with
population growth and biological parameter studies. According to Probit analyses the concentration of neem oil Bioneem
which kills 50% of the population (LC50) of M. tanajoa was 3.28 μL cm^-2, which is roughly twice the field concentration
recommended of this biopesticide to control pest mites (1.7 μL cm^-2). The growth rate of the cassava green mite steadily
decreased with dosages of neem oil. Furthermore, sublethal concentrations of the neem oil corresponding to the LC50
reduced the periods of the immature stages of M. tanajoa resulting in a shorter developmental time. Similarly, the number
of eggs per day and the number of eggs per female per day, a proxy for fecundity, were drastically reduced in M. tanajoa
females exposed to the LC50 of neem oil. Based on our comprehensive approach we conclude that the neem oil showed
lethal as well as sublethal toxicity on growth rate and biological parameters such as duration of immature stages and
fecundity of the cassava green mite M. tanajoa and it could be used as an ecological alternative for the management of this
pest
Susceptibility of adult female Aedes aegypti (Diptera: Culicidae) to the entomopathogenic fungus Metarhizium anisopliae is modified following blood feeding
<p>Abstract</p> <p>Background</p> <p>The mosquito <it>Aedes aegypti</it>, vector of dengue fever, is a target for control by entomopathogenic fungi. Recent studies by our group have shown the susceptibility of adult <it>A. aegypti </it>to fungal infection by <it>Metarhizium anisopliae</it>. This fungus is currently being tested under field conditions. However, it is unknown whether blood-fed <it>A. aegypti </it>females are equally susceptible to infection by entomopathogenic fungi as sucrose fed females. Insect populations will be composed of females in a range of nutritional states. The fungus should be equally efficient at reducing survival of insects that rest on fungus impregnated surfaces following a blood meal as those coming into contact with fungi before host feeding. This could be an important factor when considering the behavior of <it>A. aegypti </it>females that can blood feed on multiple hosts over a short time period.</p> <p>Methods</p> <p>Female <it>A. aegypti </it>of the Rockefeller strain and a wild strain were infected with two isolates of the entomopathogenic fungus <it>M. anisopliae </it>(LPP 133 and ESALQ 818) using an indirect contact bioassay at different times following blood feeding. Survival rates were monitored on a daily basis and one-way analysis of variance combined with Duncan's <it>post-hoc </it>test or Log-rank survival curve analysis were used for statistical comparisons of susceptibility to infection.</p> <p>Results</p> <p>Blood feeding rapidly reduced susceptibility to infection, determined by the difference in survival rates and survival curves, when females were exposed to either of the two <it>M. anisopliae </it>isolates. Following a time lag which probably coincided with digestion of the blood meal (96-120 h post-feeding), host susceptibility to infection returned to pre-blood fed (sucrose fed) levels.</p> <p>Conclusions</p> <p>Reduced susceptibility of <it>A. aegypti </it>to fungi following a blood meal is of concern. Furthermore, engorged females seeking out intra-domicile resting places post-blood feeding, would be predicted to rest for prolonged periods on fungus impregnated black cloths, thus optimizing infection rates. It should be remembered that lowered susceptibility was only a temporary phenomenon and this may not necessarily occur when mosquitoes are infected with other fungal isolates. These results may have implications for field testing of entomopathogenic fungi by our group and further studies should be carried out to better understand the insect-fungus interaction.</p
Prior Low- or High-Intensity Exercise Alters Pacing Strategy, Energy System Contribution and Performance during a 4-km Cycling Time Trial
We analyzed the influence of prior exercise designed to reduce predominantly muscle glycogen in either type I or II fibers on pacing and performance during a 4-km cycling time trial (TT). After preliminary and familiarization trials, in a randomized, repeated-measures crossover design, ten amateur cyclists performed: 1) an exercise designed to reduce glycogen of type I muscle fibers, followed by a 4-km TT (EX-FIB I); 2) an exercise designed to reduce glycogen of type II muscle fibers, followed by a 4-km TT (EX-FIB II) and; 3) a 4-km TT, without the prior exercise (CONT). the muscle-glycogen-reducing exercise in both EX-FIB I and EX-FIB II was performed in the evening, similar to 12 h before the 4-km TT. Performance time was increased and power output (PO) was reduced in EX-FIB I (432.8 +/- 8.3 s and 204.9 +/- 10.9 W) and EX-FIB II (428.7 +/- 6.7 s and 207.5 +/- 9.1 W) compared to CONT (420.8 +/- 6.4 s and 218.4 +/- 9.3 W; P0.05). the PO was lower in EX-FIB I than in CONT at the beginning and middle of the trial (P0.05). the integrated electromyography was unchanged between conditions (P>0.05). Performance may have been impaired in EX-FIB I due a more conservative pacing at the beginning and middle, which was associated with a reduced aerobic contribution. in turn, the PO profile adopted in EX-FIB II was also reduced throughout the trial, but the impairment in performance may be attributed to a reduced glycolytic contribution (i.e. reduced lactate accumulation).Foundation of Aids to Scientific Research of the State of Alagoas (FAPEAL)Univ Fed Pernambuco, CAV, Dept Phys Educ & Sports Sci, Sports Sci Res Grp, Vitoria de Santo Antao, Pernambuco, BrazilUniv São Paulo, Sch Phys Educ & Sport, Endurance Performance Res Grp, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilVictoria Univ, Coll Sport & Exercise Sci, Inst Sport Exercise & Active Living, Melbourne, Vic 8001, AustraliaUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilWeb of Scienc
Listening to Music in the First, but not the Last 1.5 km of a 5-km Running Trial Alters Pacing Strategy and Improves Performance
We examined the effects of listening to music on attentional focus, rating of perceived exertion (RPE), pacing strategy and performance during a simulated 5-km running race. 15 participants performed 2 controlled trials to establish their best baseline time, followed by 2 counterbalanced experimental trials during which they listened to music during the first (M-start) or the last (M-finish) 1.5 km. The mean running velocity during the first 1.5 km was significantly higher in M-start than in the fastest control condition (p < 0.05), but there was no difference in velocity between conditions during the last 1.5 km (p > 0.05). The faster first 1.5 m in M-start was accompanied by a reduction in associative thoughts compared with the fastest control condition. There were no significant differences in RPE between conditions (p > 0.05). These results suggest that listening to music at the beginning of a trial may draw the attentional focus away from internal sensations of fatigue to thoughts about the external environment. However, along with the reduction in associative thoughts and the increase in running velocity while listening to music, the RPE increased linearly and similarly under all conditions, suggesting that the change in velocity throughout the race may be to maintain the same rate of RPE increase.Australian Department of Education, Employment and Workplace RelationsAustralian Department of Education, Employment and Workplace Relation
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