We compute the magnetic-field-induced modifications to the boson self-coupling and the boson-fermion coupling, in the static limit, using an effective model of QCD, the linear sigma model with ...quarks. The former is computed for arbitrary field strengths as well as using the strong field approximation. The latter is obtained in the strong field limit. The arbitrary field result for the boson self-coupling depends on the ultraviolet renormalization scale, and this dependence cannot be removed by a simple vacuum subtraction. Using the strong field result as a guide, we find the appropriate choice for this scale and discuss the physical implications. The boson-fermion coupling depends on the Schwinger phase, and we show how this phase can be treated consistently in such a way that the magnetic-field-induced vertex modification is both gauge invariant and can be written with an explicit factor corresponding to energy-momentum conservation for the external particles. Both couplings show a modest decrease with the field strength.
ABSTRACT A new species of Hyphessobrycon belonging to the Hyphessobrycon heterorhabdus species-group from the lower rio Tapajós, state of Pará, Brazil, is described. The new species is allocated into ...the Hyphessobrycon heterorhabdus species-group due to its color pattern, composed by an anteriorly well-defined, horizontally elongated humeral blotch that becomes diffuse and blurred posteriorly, where it overlaps with a conspicuous midlateral dark stripe that becomes blurred towards the caudal peduncle and the presence, in living specimens, of a tricolored longitudinal pattern composed by a dorsal red or reddish longitudinal stripe, a middle iridescent, golden or silvery longitudinal stripe, and a more ventrally-lying longitudinal dark pattern composed by the humeral blotch and dark midlateral stripe. It can be distinguished from all other species of the group by possessing humeral blotch with a straight or slightly rounded ventral profile, lacking a ventral expansion present in all other species of the group. The new species is also distinguished from Hyphessobrycon heterorhabdus by a 9.6% genetic distance in the cytochrome c oxidase I gene. The little morphological distinction of the new species when compared with its most similar congener, H. heterorhabdus, indicates that the new species is one of the first truly cryptic fish species described from the Amazon basin.
RESUMO Uma nova espécie de Hyphessobrycon pertencente ao grupo Hyphessobrycon heterorhabdus é descrita da região do baixo rio Tapajós, estado do Pará, Brasil. A nova espécie é incluída no grupo Hyphessobrycon heterorhabdus devido ao seu padrão de coloração, composto por uma mancha umeral alongada, anteriormente bem definida, que se torna difusa e borrada posteriormente, onde se sobrepõe a uma conspícua faixa escura médio-lateral que se torna borrada próxima ao pedúnculo caudal, e pela presença, em exemplares vivos, de um padrão longitudinal tricolor, composto por uma faixa longitudinal vermelha ou avermelhada dorsal, uma faixa média iridescente dourada ou prateada e, mais ventralmente, o padrão longitudinal escuro composto pela faixa escura médio-lateral e mancha umeral. A espécie pode ser distinguida das outras espécies pertencentes ao grupo por possuir uma mancha umeral com região ventral retilínea ou levemente arredondada, sem uma expansão ventral presente nas demais espécies do grupo. A espécie também se diferencia de Hyphessobrycon heterorhabdus por uma distância genética de 9,6% no gene citocromo c oxidase I. A sutil diferença morfológica da nova espécie quando comparada ao seu congênere mais similar, H. heterorhabdus, indica que a nova espécie é uma das primeiras espécies de peixes verdadeiramente crípticas descritas da Bacia Amazônica.
Nurturant behavior toward dead conspecifics has been documented in several free-ranging marine and terrestrial mammals but still remains undocumented and poorly understood for most species. This ...study describes observations of adults carrying dead calves and juveniles in 7 odontocetes (toothed cetaceans) species and discusses the subject in mammals in general. Observations are based on 14 events from 3 oceans and constitute the 1st records for Indo-Pacific bottlenose dolphins (Tursiops aduncus), spinner dolphins (Stenella longirostris), killer whales (Orcinus orca), Australian humpback dolphins (Sousa sahulensis), and sperm whales (Physeter macrocephalus), as well as presenting additional records for Risso’s dolphins (Grampus griseus) and short-finned pilot whales (Globicephala macrorhynchus). Information on how the adults supported and carried the dead conspecifics, on the gender of both adults and dead young, and on the age class of the dead young, is presented. Moreover, a comparison with terrestrial mammals, including a compilation of published literature, and a discussion on possible hypotheses to explain this particular type of behavior are given. The present study helps to corroborate that adults mourning their dead young is a common and globally widespread behavior in long-lived and highly sociable/cohesive species of mammals.
AbstractThis paper proposes a reliability-based framework for quantifying structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, ...such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of three, nine, and 20 stories, which were designed to pre-Northridge codes and standards. Two-dimensional nonlinear finite-element models of the buildings are developed with the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability based robustness indicator shows that the structural robustness is influenced by the extent to which a structure can distribute damage.
Celotno besedilo
Dostopno za:
DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Functional attributes of a thermostable β-(1→4)-mannanase were investigated from Clostridium thermocellum ATCC 27405. Its sequence comparison the exhibited highest similarity with Man26B of C. ...thermocellum F1. The full length CtManf and truncated CtManT were cloned in the pET28a(+) vector and expressed in E. coli BL21(DE3) cells, exhibiting 53 kDa and 38 kDa proteins, respectively. On the basis of the substrate specificity and hydrolyzed product profile, CtManf and CtManT were classified as β-(1→4)-mannanase. A 1.5 fold higher activity of both enzymes was observed by Ca2+ and Mg2+ salts. Plausible mannanase activity of CtManf was revealed by the classical hydrolysis pattern of carob galactomannan and the release of manno-oligosaccharides. Notably highest protein concentrations of CtManf and CtManT were achieved in tryptone yeast extract (TY) medium, as compared with other defined media. Both CtManf and CtManT displayed stability at 60 and 50 °C, respectively, and Ca2+ ions imparted higher thermostability, resisting their melting up to 100 °C.
There is evidence that physiological signals under healthy conditions may have a fractal temporal structure. Here we investigate the possibility that time series generated by certain physiological ...control systems may be members of a special class of complex processes, termed multifractal, which require a large number of exponents to characterize their scaling properties. We report on evidence for multifractality in a biological dynamical system, the healthy human heartbeat, and show that the multifractal character and nonlinear properties of the healthy heart rate are encoded in the Fourier phases. We uncover a loss of multifractality for a life-threatening condition, congestive heart failure.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An efficient and unprecedented
S
-glycosylation reaction of benzo-2,1,3-thiadiazole at the C-5-position using a Pd-G
3
Xantphos palladacycle precatalyst has been described. This methodology showed a ...high functional group tolerance to the electrophilic partner and can be successfully applied to a variety of β-mono- and di-thiosugar derivatives. A series of thioglycoside derivatives from benzo-2,1,3-thiadiazole were prepared in good to excellent yields under mild and operationally simple reaction conditions.
Structure modification of thioglycosides by cross-coupling reaction using aglycones with biological properties, such as AChE and angiotensin II inhibitors.
This paper investigates the use of a virtual synchronous machine (VSM) to support dynamic frequency control in a diesel-hybrid autonomous power system. The proposed VSM entails controlling the ...grid-interface converter of an energy storage system (ESS) to emulate the inertial response and the damping power of a synchronous generator. In addition, self-tuning algorithms are used to continuously search for optimal parameters during the operation of the VSM in order to minimize the amplitude and rate of change of the frequency variations and the power flow through the ESS. The performances of the proposed self-tuning (ST)-VSM and the constant parameters (CP)-VSM were evaluated by comparing their inertial responses and their damping powers for different scenarios of load variations. For the simulated cases, the ST-VSM achieved a similar performance to that of the CP-VSM, while reducing the power flow through the ESS in up to 58%. Moreover, in all the simulated scenarios, the ST-VSM was found to be more efficient than the CP-VSM in attenuating frequency variations, i.e., it used less energy per Hertz reduced.
The seasonal chemical composition of essential oils from Inga laurina was determined by GC/MS. In the stem bark's essential oil extracted during the dry season, the presence of terpenoids (30.05%) ...stood out, and phytol (9.76%) was the major compound identified. For the stem bark oil obtained during the rainy season, in addition to terpenoids (26.63%), a large amount of fatty acids (46.84%) were identified, in particular palmitic acid (25.40%). Regarding the leaves' essential oil obtained in the dry season, esters (42.35%) were the main components. The main ester present was (Z)-hex-3-enyl benzoate (10.15%) and the major compound of this oil was (Z)-hex-3-en-1-ol (14.23%). Terpenoids (33.84%), long-chain alkanes (27.04%) and fatty acids (21.72%) were the main components of the essential oil from leaves in the rainy season. Phytol (33.21%), nonacosane (21.95%) and palmitic acid (15.20%) were the major compounds identified. The antimicrobial activity against aerobic and anaerobic oral bacteria was evaluated by the microdilution broth method and cytotoxic activity was carried out with Vero cells. The essential oils from the rainy season showed a better inhibition of the bacterial growth with Minimal Inhibitory Concentrations (MIC) values of 25 or 50 µg·mL⁻¹ for aerobic bacteria, and high selectivity against bacteria was observed. The large amount of fatty acids in rainy season oils may be related to the better inhibitory effects observed.
Measuring cortisol levels as a stress biomarker is essential in many medical conditions associated with a high risk of metabolic syndromes such as anxiety and cardiovascular diseases, among others. ...One technology that has a growing interest in recent years is fiber optic biosensors that enable ultrasensitive cortisol detection. Such interest is allied with progress being achieved in basic interrogation, accuracy improvements, and novel applications. The development of improved cortisol monitoring, with a simplified manufacturing process, high reproducibility, and low cost, are challenges that these sensing mechanisms still face, and for which solutions are still needed. In this paper, a comprehensive characterization of a D-shaped fiber optic immunosensor for cortisol detection based on surface plasmon resonance (SPR) enabled by gold coating is reported. Specifically, the sensor instrumentation and fabrication processes are discussed in detail, and a simulation with its complete mathematical formalism is also presented. Moreover, experimental cortisol detection tests were performed for a detection range of 0.01 to 100 ng/mL, attaining a logarithmic sensitivity of 0.65 ± 0.02 nm/log(ng/mL) with a limit of detection (LOD) of 1.46 ng/mL. Additionally, an investigation of signal processing is also discussed, with the main issues addressed in order to highlight the best way to extract the sensing information from the spectra measured with a D-shaped sensor.
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