Abstract The mycotoxigenic fungus Fusarium verticillioides is the primary maize pathogen and causes the maize stalk and ear rot diseases with significant economic losses. Furthermore, the excessive ...use of fungicides to control F. verticillioides constitutes threats to the environment and human health. Thus, sustainable alternatives such as biological control are needed to minimize the hazards associated with the current method. Although much is known about the vulnerability of the maize silks as a gateway for several fungal pathogens invading the developing grains, studies on the chemical properties of silk extracts and their resident microbiota are scarce. This study isolated and characterized bacteria and fungi that colonize the maize stigma to assess new potential biocontrol agents. The samples were collected from maize fields in the Brazilian localities of Sete Lagoas-MG, Sidrolândia-MS, Sertaneja-PR, and Goiânia-GO. One hundred sixty-seven microorganisms were isolated, 46% endophytic and 54% epiphytic. First, the antagonist activity was evaluated by the agar disc diffusion method performed in triplicate, and 83% of the isolates showed antagonist activity against F. verticillioides. Then, the 42 most efficient isolates were identified based on the partial sequencing of the bacterial 16S rRNA gene and fungi ITS region. The bacteria belong to the genera Bacillus (57.1%), Burkholderia (23.8%), Achromobacter (7.1%), Pseudomonas (2.4%), and Serratia (2.4%), while the fungi are Penicillium (2.4%), Candida (2.4), and Aspergillus (2.4%). The results showed that microorganisms from maize stigma might represent new promising agents for F. verticillioides control.
Resumo O fungo micotoxigênico Fusarium verticillioides é o principal patógeno do milho e causa doenças do colmo e da podridão da espiga com perdas econômicas significativas. Além disso, o uso excessivo de fungicidas no controle de F. verticillioides constitui uma ameaça ao meio ambiente e à saúde humana. Assim, alternativas sustentáveis, como o controle biológico, são necessárias para minimizar os riscos associados ao método atual. Este estudo isolou e caracterizou bactérias e fungos que colonizam o estigma do milho para avaliar novos agentes de biocontrole em potencial. As amostras foram coletadas em campos de milho nas localidades brasileiras de Sete Lagoas-MG, Sidrolândia-MS, Sertaneja-PR e Goiânia-GO. Cento e sessenta e sete microrganismos foram isolados, 46% endofíticos e 54% epifíticos. O teste de antagonismo empregando a técnica de disco de difusão em meio sólido, mostrou que 83% dos isolados apresentaram atividade antagonista contra F. verticillioides. Em seguida, 42 isolados mais eficientes foram identificados a partir do sequenciamento parcial do gene 16S rRNA bacteriano e da região ITS de fungos. Os isolados bacterianos pertencem ao gênero Bacillus (57,1%), Burkholderia (23,8%), Achromobacter (7,1%), Pseudomonas (2,4%) e Serratia (2,4%), enquanto os fungos são Penicillium (2,4%), Candida (2.4), e Aspergillus (2,4%). Os resultados mostraram que microrganismos do estigma do milho podem representar novos agentes promissores para o controle de F. verticillioides.
This article presents an Evolution Strategy (ES)--based algorithm, designed to self-adapt its mutation operators, guiding the search into the solution space using a Self-Adaptive Reduced Variable ...Neighborhood Search procedure. In view of the specific local search operators for each individual, the proposed population-based approach also fits into the context of the Memetic Algorithms. The proposed variant uses the Greedy Randomized Adaptive Search Procedure with different greedy parameters for generating its initial population, providing an interesting exploration–exploitation balance. To validate the proposal, this framework is applied to solve three different
-Hard combinatorial optimization problems: an Open-Pit-Mining Operational Planning Problem with dynamic allocation of trucks, an Unrelated Parallel Machine Scheduling Problem with Setup Times, and the calibration of a hybrid fuzzy model for Short-Term Load Forecasting. Computational results point out the convergence of the proposed model and highlight its ability in combining the application of move operations from distinct neighborhood structures along the optimization. The results gathered and reported in this article represent a collective evidence of the performance of the method in challenging combinatorial optimization problems from different application domains. The proposed evolution strategy demonstrates an ability of adapting the strength of the mutation disturbance during the generations of its evolution process. The effectiveness of the proposal motivates the application of this novel evolutionary framework for solving other combinatorial optimization problems.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Visceral leishmaniasis (VL) is a rare disease in solid-organ transplant (SOT) recipients. Therefore, little is known about the risk factors and disease behavior in the transplant setting. This ...multicenter, matched case–control study (1:2 ratio) was designed to determine the risk factors, clinical features and outcomes of VL among this population. Control and case subjects were matched by center, transplant type and timing. Thirty-six VL cases were identified among 25 139 SOT recipients (0.1%). VL occurred 5.7-fold more frequently in Brazil than in Spain, presenting a median time of 11 months after transplantation. High-dose prednisone in the preceding 6 months was associated with VL. Patients were diagnosed over 1 month after symptom onset in 25% of cases. Thirty-one patients (86%) were febrile upon diagnosis, 81% exhibited visceromegaly and 47% showed pancytopenia. Concomitant infection was common. Parasites were identified in 89% of patients; the remaining patients were diagnosed by serology. The majority of the patients received amphotericin B. Relapses occurred in 25.7% of cases, and the crude mortality rate was 2.8%. VL after SOT is related to the VL prevalence in the general population. Delayed diagnosis frequently occurs. Liposomal amphotericin is the most commonly used therapy; mortality is low, although relapses are common.
As part of the 2002 Shelf-Basin Interactions (SBI) process study, measurements of the seasonal variation in the export flux of particulate organic carbon (POC) are reported for the upper waters of ...the Chukchi Sea. POC fluxes were quantified by determination of
234Th/
238U disequilibrium and POC/
234Th ratios in large
(
>
53
μ
m
)
aggregates collected using in situ pumps. Samples were collected at 35 stations on two cruises, one in predominantly ice-coved conditions during the spring (May 6–June 15) and the other in predominantly open water during the summer (July 17–August 26). Enhanced particle export was observed in the shelf and slope waters, particularly within Barrow Canyon, and there was a marked increase in particle export at all stations during the summer (July–August) relative to the spring (May–June).
234Th-derived POC fluxes exhibit significant seasonal and spatial variability, averaging
2.9
±
5.3
mmol
C
m
-
2
d
-
1
(
range
=
0.031
–
22
mmol
C
m
-
2
d
-
1
)
in the spring and increasing
∼
4
-fold in the summer to an average value of
10.5
±
9.3
mmol
C
m
-
2
d
-
1
(
range
=
0.79
–
39
mmol
C
m
-
2
d
-
1
)
. The fraction of primary production exported from the upper waters increases from
∼
15
%
in the spring to
∼
32
%
in the summer. By comparison, DOC accumulation associated with net community production represented
∼
6
%
of primary production
(
∼
2
mmol
C
m
-
2
d
-
1
)
. The majority of shelf and slope stations indicate a close agreement between POC export and benthic C respiration in the spring, whereas there is an imbalance between POC export and benthic respiration in the summer. The implication is that up to
∼
20
%
of summer production
(
∼
6
±
7
mmol
C
m
-
2
d
-
1
)
may be seasonally exported off-shelf in this productive shelf/slope region of the Arctic Ocean.
Abstract
The extensive set of measurements performed during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment provides a unique opportunity to evaluate aerosol ...retrievals over the ocean from multiangle, multispectral photometric, and polarimetric remote sensing observations by the airborne Research Scanning Polarimeter (RSP) instrument.
Previous studies have shown the feasibility of retrieving particle size distributions and real refractive indices from such observations for visible wavelengths without prior knowledge of the ocean color. This work evaluates the fidelity of the aerosol retrievals using RSP measurements during the CLAMS experiment against aerosol properties derived from in situ measurements, sky radiance observations, and sun-photometer measurements, and further extends the scope of the RSP retrievals by using a priori information about the ocean color to constrain the aerosol absorption and vertical distribution.
It is shown that the fine component of the aerosol observed on 17 July 2001 consisted predominantly of dirty sulfatelike particles with an extinction optical thickness of several tenths in the visible, an effective radius of 0.15 ± 0.025 μm and a single scattering albedo of 0.91 ± 0.03 at 550 nm. Analyses of the ocean color and sky radiance observations favor the lower boundary of aerosol single scattering albedo, while in situ measurements favor its upper boundary. Both analyses support the polarimetric retrievals of fine-aerosol effective radius and the consequent spectral variation in extinction optical depth. The estimated vertical distribution of this aerosol component depends on assumptions regarding the water-leaving radiances and is consistent with the top of the aerosol layer being close to the aircraft height (3500 m), with the bottom of the layer being between 2.7 km and the surface. The aerosol observed on 17 July 2001 also contained coarse-mode particles. Comparison of RSP data with sky radiance and in situ measurements suggests that this component consists of nonspherical particles with an effective radius in excess of 1 μm, and with the extinction optical depth being much less than one-tenth at 550 nm.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
6.
A Brief History of Gravitational Waves Cervantes-Cota, Jorge; Galindo-Uribarri, Salvador; Smoot, George
Universe,
09/2016, Letnik:
2, Številka:
3
Journal Article
Recenzirano
Odprti dostop
This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by ...Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery.
“Global” algorithms for satellite remote sensing do not always provide accurate retrievals in all areas of the ocean, particularly in coastal areas and high latitudes. Our current arctic algorithm ...shows that low chlorophyll concentrations (∼0.6 mg m
−3) are overestimated by the OC4V4 algorithm for Sea-viewing Wide Field-of-view Sensor (SeaWiFS), while higher concentrations common in blooms are underestimated almost twofold. Alternative algorithms or regionally tuned relationships can be used to produce more reliable chlorophyll retrievals; however, reprocessing of huge satellite data sets can be untenable. Several approaches were investigated to convert global products into regional values to improve accuracy while minimizing errors across the range of values. A simple, rapid transformation scheme employing linear interpolation circumvents reprocessing of entire data sets, but yields much more accurate regional values for the Arctic.
Donor-derived tuberculosis (DD-TB) accounts for less than 5% of TB cases and is considered a rare event. In the transplant setting, the frequency of active TB is estimated to be 20 to 74 times higher ...than that in the general population, and it is associated with high mortality. In this context, the main strategy to minimize the risk of DD transmission is to identify high-risk donors. Despite screening recommendations, failures may result in a breakdown of safety that ends in the transmission of potentially fatal diseases. This report describes a case of DD-TB and emphasizes communication gaps that may occur between organ procurement organizations and transplant centers. Failure in reporting results, lack of exchanging information regarding recipients from the same donor, and inefficient communication between organ procurement organizations and transplant centers are lacks that may be prevented by a more efficient approach towards screening protocols and communication.
The outcomes of HIV-infected patients requiring critical care have improved. However, in developing countries, information about HIV-infected patients admitted to intensive care units (ICUs) is ...scarce. We describe the prognosis of HIV-infected patients admitted to a Brazilian ICU and the factors predictive of short- and long-term survival. A historical cohort study, including HIV-infected patients admitted to a Brazilian ICU at an HIV/AIDS reference hospital, was conducted. Survivors were followed up for 24 months after ICU discharge. Demographic, clinical and laboratory data, disease severity scores and mortality were evaluated. Data were analysed using survival and regression models. One hundred and twenty-five patients were studied. In-ICU and in-hospital mortality rates were 46.4% and 68.0%, respectively. Multivariate analysis showed that the in-ICU mortality was significantly associated with APACHE (Acute Physiology and Chronic Health Evaluation) II scores (odds ratio OR, 1.11; 95% confidence interval CI, 1.03-1.11), mechanical ventilation (OR, 6.39; 95% CI, 1.29-31.76), tuberculosis treatment (OR, 2.62; 95% CI, 1.03-6.71), use of antiretroviral therapy (OR, 0.19; 95% CI, 0.05-0.77) and septic shock (OR, 4.38; 95% CI, 1.78-10.76). Septic shock was also associated with long-term survival (hazard ratio, 3.0; 95% CI, 1.31-6.90). In-hospital and in-ICU mortality were higher than those reported for developed countries. ICU admission mostly due to AIDS-related diseases may explain these differences.
Bio-optical properties of the Labrador Sea Cota, Glenn F.; Harrison, W. Glen; Platt, Trevor ...
Journal of Geophysical Research - Oceans,
July 2003, Letnik:
108, Številka:
C7
Journal Article
Recenzirano
Odprti dostop
Three cruises were conducted during fall and spring in the Labrador Sea to investigate the effects of bio‐optical properties on satellite retrievals of phytoplankton chlorophyll in this important ...high‐latitude ecosystem. Taxon‐specific and regional differences were found. Diatoms had ∼1.5 lower chlorophyll‐specific absorption but significantly higher reflectance ratios than prymnesiophytes. Particulate absorption at 443 nm for total, phytoplankton, and “detrital” fractions was related to chlorophyll, but values were lower than reported for lower latitudes. Decreased particulate absorption is attributed primarily to pigment packaging, while low backscattering to scattering ratios result from a lower relative abundance of bacteria and picophytoplankton with more large phytoplankton. Soluble absorption was not related to chlorophyll. A four‐component model with low, variable backscatter fractions and the observed absorption coefficients for phytoplankton, “detritus,” and soluble materials reproduces the measured reflectance spectra. Global chlorophyll algorithms tend to underestimate biomass at high latitudes, whereas regionally tuned algorithms provide more reliable retrievals. Taxon‐specific algorithms show promise, but given limited ranges, small sample sizes, and overlapping reflectance ratios they remain premature.
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