1,625 research outputs found
Eficiência e viabilidade econômica da aplicação de fungicidas no controle da ferrugem asiática da soja em Campo Grande, MS.
Objetivou-se avaliar a eficiência e a viabilidade econômica da aplicação de fungicidas no controle da ferrugem asiática da soja, Phakopsora packyrhizi, em Campo Grande, MS. O ensaio foi conduzido em na safra 2007-2008. Foram avaliados os fungicidas (g i.a./ha): picoxistrobina + ciproconazole (40 + 16, 50 + 20 e 60 + 24) + nimbus 0,25% (v/v), piraclostrobina + epoxiconazole (66,5 + 25); azoxistrobina + ciproconazole (60 + 24) + nimbus 0,25% (v/v); trifloxistrobina + tebuconazole (50 + 100) + auero 0,13% (v/v) e trifloxistrobina + ciproconazole (56,25 + 24) + aureo 0,13% (v/v). Três aplicações foram realizadas, quinzenalmente, a partir do estádio fenológico R2. Foram realizadas 10 avaliações da severidade da doença (terços inferior e superior da planta) e três da desfolha (a partir do estádio R7), com intervalos de sete dias. Após plotagem das curvas de progresso (CP), foram calculadas as áreas abaixo das CP para a severidade da doença (AACPD) e desfolha (AACPDes). Ao final do ensaio, avaliou-se o rendimento de grãos (Rend - kg/ha), a massa de 1.000 grãos (MMG - g) e a viabilidade econômica do controle da doença. O clima durante a condução do ensaio foi favorável ao desenvolvimento da ferrugem asiática, constatando-se relação positiva entre a precipitação e a severidade da doença. Todos os fungicidas apresentaram valores de AACPD inferiores ao da testemunha, com destaque para picoxistrobina + ciproconazole (maior dose). Esse tratamento também apresentou o menor índice de AACPDes. Os fungicidas apresentaram índices semelhantes de Rend, embora superiores à testemunha. Quanto a MMG, maior índice foi atribuído a azoxistrobina + ciproconazole. A mistura trifloxistrobina + tebuconazole apresentou a menor eficiência de controle da ferrugem asiática. Com base na severidade da doença, rendimento de grãos e nos benefícios econômico gerados pela aplicação de fungicidas, identificou-se os fungicidas picoxistrobina + ciproconazole (60 + 24), azoxistrobina + ciproconazole e trifloxistrobina + ciproconazole como os mais promissores para o controle de P. packyrhizi
Cataclysmic Variables and a New Class of Faint UV Stars in the Globular Cluster NGC 6397
We present evidence that the globular cluster NGC 6397 contains two distinct
classes of centrally-concentrated UV-bright stars. Color-magnitude diagrams
constructed from U, B, V, and I data obtained with the HST/WFPC2 reveal seven
UV-bright stars fainter than the main-sequence turnoff, three of which had
previously been identified as cataclysmic variables (CVs). Lightcurves of these
stars show the characteristic ``flicker'' of CVs, as well as longer-term
variability. A fourth star is identified as a CV candidate on the basis of its
variability and UV excess. Three additional UV-bright stars show no photometric
variability and have broad-band colors characteristic of B stars. These
non-flickering UV stars are too faint to be extended horizontal branch stars.
We suggest that they could be low-mass helium white dwarfs, formed when the
evolution of a red giant is interrupted, due either to Roche-lobe overflow onto
a binary companion, or to envelope ejection following a common-envelope phase
in a tidal-capture binary. Alternatively, they could be very-low-mass
core-He-burning stars. Both the CVs and the new class of faint UV stars are
strongly concentrated toward the cluster center, to the extent that mass
segregation from 2-body relaxation alone may be unable to explain their
distribution.Comment: 11 pages plus 3 eps figures; LaTeX using aaspp4.sty; to appear in The
Astrophysical Journal Letter
Contribution of White Dwarfs to Cluster Masses
I present a literature search through 31 July 1997 of white dwarfs (WDs) in
open and globular clusters. There are 36 single WDs and 5 WDs in binaries known
among 13 open clusters, and 340 single WDs and 11 WDs in binaries known among
11 globular clusters. From these data I have calculated WD mass fractions for
four open clusters (the Pleiades, NGC 2168, NGC 3532, and the Hyades) and one
globular cluster (NGC 6121). I develop a simple model of cluster evolution that
incorporates stellar evolution but not dynamical evolution to interpret the WD
mass fractions. I augment the results of my simple model with N-body
simulations incorporating stellar evolution (Terlevich 1987; de la Feunte
Marcos 1996; Vesperini & Heggie 1997). I find that even though these clusters
undergo moderate to strong kinematical evolution the WD mass fraction is
relatively insensitive to kinematical evolution. By comparing the cluster mass
functions to that of the Galactic disk, and incorporating plausibility
arguments for the mass function of the Galactic halo, I estimate the WD mass
fraction in these two populations. I assume the Galactic disk is ~10 Gyrs old
(Winget et al. 1987; Liebert, Dahn, & Monet 1988; Oswalt et al. 1996) and that
the Galactic halo is ~12 Gyrs old (Reid 1997b; Gratton et al. 1997; Chaboyer et
al. 1998), although the WD mass fraction is insensitive to age in this range. I
find that the Galactic halo should contain 8 to 9% (alpha = -2.35) or perhaps
as much as 15 to 17% (alpha = -2.0) of its stellar mass in the form of WDs. The
Galactic disk WD mass fraction should be 6 to 7% (alpha = -2.35), consistent
with the empirical estimates of 3 to 7% (Liebert, Dahn, & Monet 1988; Oswalt et
al. 1996). (abridged)Comment: 20 pages, uuencoded gunzip'ed latex + 3 postscrip figures, to be
published in AJ, April, 199
The Evolution of Globular Clusters in the Galaxy
We investigate the evolution of globular clusters using N-body calculations
and anisotropic Fokker-Planck (FP) calculations. The models include a mass
spectrum, mass loss due to stellar evolution, and the tidal field of the parent
galaxy. Recent N-body calculations have revealed a serious discrepancy between
the results of N-body calculations and isotropic FP calculations. The main
reason for the discrepancy is an oversimplified treatment of the tidal field
employed in the isotropic FP models. In this paper we perform a series of
calculations with anisotropic FP models with a better treatment of the tidal
boundary and compare these with N-body calculations. The new tidal boundary
condition in our FP model includes one free parameter. We find that a single
value of this parameter gives satisfactory agreement between the N-body and FP
models over a wide range of initial conditions.
Using the improved FP model, we carry out an extensive survey of the
evolution of globular clusters over a wide range of initial conditions varying
the slope of the mass function, the central concentration, and the relaxation
time. The evolution of clusters is followed up to the moment of core collapse
or the disruption of the clusters in the tidal field of the parent galaxy. In
general, our model clusters, calculated with the anisotropic FP model with the
improved treatment for the tidal boundary, live longer than isotropic models.
The difference in the lifetime between the isotropic and anisotropic models is
particularly large when the effect of mass loss via stellar evolution is rather
significant. On the other hand the difference is small for relaxation-
dominated clusters which initially have steep mass functions and high central
concentrations.Comment: 36 pages, 11 figures, LaTeX; added figures and tables; accepted by
Ap
JAK-2 inhibitors and allogeneic transplant in myelofibrosis
7The activation of the JAK1/JAK2 pathway plays a crucial role in the pathogenesis of myelofibrosis. Treatment with the JAK2 inhibitor ruxolitinib demonstrated to reduce splenomegaly and symptoms in patients affected by myelofibrosis, leading to a significant improvement of overall survival in comparison with the supportive therapies. Taking in account this recent therapeutic progress, it is necessary to redefine the role of the allogeneic hematopoietic stem cell transplantation, which has been considered the only curative option for fit myelofibrosis patients up to now. In the era of JAK2 inhibitors, allogeneic transplant is still indicated in patients with intermediate-2 and high-risk myelofibrosis or red blood cell transfusion dependent patients or patients with unfavourable karyotype. There is no direct evidence to recommend which conditioning regimen should be preferentially adopted. Graft failure, relapse and transplant related mortality are still current issues of the allogeneic stem cell transplantation, particularly from unrelated donors. Ruxolitinib can be efficaciously included in the platform of allogeneic transplant. In fact, ruxolitinib treatment for 3-4 months before transplant has demonstrated to reduce spleen and improve performance status in about 30-50% of patients, without impairing the outcome of the subsequent transplant. Ruxolitinib has to stopped the day before conditioning to avoid rebound phenomenon. There are no sufficient data to recommend ruxolitinib administration after transplant with the aim of eradicating minimal residual disease and preventing relapse.openopenPatriarca, F; Sperotto, A; De Marchi, R; Perali, G; Cigana, C; Lazzarotto, D; Fanin, RPatriarca, Francesca; Sperotto, A; De Marchi, R; Perali, G; Cigana, C; Lazzarotto, D; Fanin, Renat
Heavy element abundances in giant stars of the globular clusters M4 and M5
We present a comprehensive abundance analysis of 27 heavy elements in bright
giant stars of the globular clusters M4 and M5 based on high resolution, high
signal-to-noise ratio spectra obtained with the Magellan Clay Telescope. We
confirm and expand upon previous results for these clusters by showing that (1)
all elements heavier than, and including, Si have constant abundances within
each cluster, (2) the elements from Ca to Ni have indistinguishable
compositions in M4 and M5, (3) Si, Cu, Zn, and all s-process elements are
approximately 0.3 dex overabundant in M4 relative to M5, and (4) the r-process
elements Sm, Eu, Gd, and Th are slightly overabundant in M5 relative to M4. The
cluster-to-cluster abundance differences for Cu and Zn are intriguing,
especially in light of their uncertain nucleosynthetic origins. We confirm that
stars other than Type Ia supernovae must produce significant amounts of Cu and
Zn at or below the clusters' metallicities. If intermediate-mass AGB stars or
massive stars are responsible for the Cu and Zn enhancements in M4, the similar
[Rb/Zr] ratios and (preliminary) Mg isotope ratios in both clusters may be
problematic for either scenario. For the elements from Ba to Hf, we assume that
the s- and r-process contributions are scaled versions of the solar s- and
r-process abundances. We quantify the relative fractions of s- and r-process
material for each cluster and show that they provide an excellent fit to the
observed abundances.Comment: Accepted for publication in Ap
Strategies for cancer treatment based on photonic nanomedicine
Traditional cancer treatments, such as surgery, radiotherapy, and chemotherapy, are still the most effective clinical practice options. However, these treatments may display moderate to severe side effects caused by their low temporal or spatial resolution. In this sense, photonic nanomedicine therapies have been arising as an alternative to traditional cancer treatments since they display more control of temporal and spatial resolution, thereby yielding fewer side effects. In this work, we reviewed the challenge of current cancer treatments, using the PubMed and Web of Science database, focusing on the advances of three prominent therapies approached by photonic nanomedicine: (i) photothermal therapy; (ii) photodynamic therapy; (iii) photoresponsive drug delivery systems. These photonic nanomedicines act on the cancer cells through different mechanisms, such as hyperthermic effect and delivery of chemotherapeutics and species that cause oxidative stress. Furthermore, we covered the recent advances in materials science applied in photonic nanomedicine, highlighting the main classes of materials used in each therapy, their applications in the context of cancer treatment, as well as their advantages, limitations, and future perspectives. Finally, although some photonic nanomedicines are undergoing clinical trials, their effectiveness in cancer treatment have already been highlighted by pre-clinical studies
Alterações nos atributos químicos do solo proveniente da adição de fontes alternativas portadoras de potássio.
Dada a enorme geodiversidade que ocorre no Brasil, a tecnologia da aplicação de pó de rocha (rochagem) configura-se como uma excelente alternativa ao fornecimento de nutrientes no solo. Objetivou-se avaliar os efeitos de fontes alternativas de nutrientes nos atributos químicos do solo em um experimento de incubação realizado em casa de vegetação. Foi conduzido em vasos com 5 kg preenchidos com um Latossolo Vermelho Amarelo distrófico de textura média, com teor de K (Mehlich-1) de 0,06 cmolc dm-3 de solo. O delineamento experimental foi inteiramente casualizado e os tratamentos foram distribuídos em arranjo fatorial 5 x 9 x 3, sendo cinco doses de potássio (0, 150, 300, 450 e 600 kg ha-1 de K2O) e nove fontes alternativas de nutrientes (verdete, 25C:75V, verdete tratado com NH4OH, ultramáfica, 25C:75U, fonolito, 25C:75F, resíduo de mineração, 25C:75R), com três repetições. As fontes alternativas de nutrientes foram aplicadas e incorporadas ao solo, deixando-os em incubação por um período de 45 dias, com a umidade em torno de 70% da capacidade de campo, e, após isto, foram feitas análises do solo. Os fertilizantes potássicos alteraram a disponibilidade de nutrientes, sendo que o resíduo de mineração e sua mistura foram os que mais liberaram K para o solo em todas as doses testadas
- …