2,684 research outputs found
Estimativa da evapotranspiração de referência no Brasil: uma análise crÃtica.
RESUMO: Devido a necessidade de quantificar a perda de água pelas grandes culturas, diversos trabalhos tem sido desenvolvidos com o objetivo de encontrar um modelo de estimativa da evapotranspiração de referência (ETo) para uma região especÃfica. Assim, o presente trabalho tem como objetivo analisar a produção cientÃfica brasileira na área de estimativa da evapotranspiração e identificando os principais métodos de estimativa da ETo utilizados para as diferentes condições climáticas brasileiras. Para isso, realizou-se uma revisão de bibliográfica de trabalhos de estimativa de ETo realizados no Brasil. Entre os 38 trabalhos encontrados para a presente discussão, foi possÃvel concluir que os métodos mais adequados foram os métodos de Blaney-Criddle FAO-24 e Radiação Solar FAO-24 para o norte e nordeste, e Thornthwaite e Camargo para o sul e sudeste, onde as regiões norte, centro-oeste e sul necessitam de maiores estudos nesta área
Generating and Revealing a Quantum Superposition of Electromagnetic Field Binomial States in a Cavity
We introduce the -photon quantum superposition of two orthogonal
generalized binomial states of electromagnetic field. We then propose, using
resonant atom-cavity interactions, non-conditional schemes to generate and
reveal such a quantum superposition for the two-photon case in a single-mode
high- cavity. We finally discuss the implementation of the proposed schemes.Comment: 4 pages, 3 figures. Title changed (published version
Gonadotropin-releasing Hormone Agonists For Ovarian Function Preservation In Premenopausal Women Undergoing Chemotherapy For Early-stage Breast Cancer: A Systematic Review And Meta-analysis
Chemotherapy may result in a detrimental effect on ovarian function and fertility in premenopausal women undergoing treatment for early-stage breast cancer (EBC). To minimize risk of harm to ovarian function and fertility for patients in this setting, careful considerations should be made. Gonadotropin-releasing hormone agonists (GnRHa) have been suggested as an alternative to prevent the loss of ovarian function due to exposure to cytotoxic agents, but GnRHa use for ovarian protection in EBC patients is not fully resolved. OBJECTIVE To determine the effectiveness of GnRHa administered concurrently with chemotherapy for ovarian function preservation. DATA SOURCES PubMed, SCOPUS, and Cochrane databases were searched for studies published between January 1975 and March 2015. The abstracts of the American Society of Clinical Oncology Annual Meeting between 1995 and 2014 and the San Antonio Breast Cancer Symposium between 2009 and 2014 were searched as well. STUDY SELECTION Prospective, randomized, clinical trials addressing the role of ovarian suppression with GnRHa in preventing early ovarian dysfunction in premenopausal women undergoing treatment for EBC were selected. DATA EXTRACTION AND SYNTHESIS Data extraction was performed independently by 2 authors. The methodology and the risk of bias were assessment based on the description of randomization method, withdrawals, and blinding process. MAIN OUTCOMES AND MEASURES Rate of resumption of regular menses after a minimal follow-up period of 6 months following chemotherapy was used as a surrogate to assess the incidence of ovarian dysfunction. Additional secondary outcomes included hormone levels and number of pregnancies. Risk ratio estimates were calculated based on the number of evaluable patients. Analyses were conducted using a random effect model. RESULTS Seven studies were included in this analysis, totaling 1047 randomized patients and 856 evaluable patients. The use of GnRHa was associated with a higher rate of recovery of regular menses after 6 months (odds ratio [OR], 2.41; 95% CI, 1.40-4.15; P = .002) and at least 12 months (OR, 1.85; 95% CI, 1.33-2.59; P < .001) following the last chemotherapy cycle. The use of GnRHa was also associated with a higher number of pregnancies (OR, 1.85; 95% CI, 1.02-3.36; P = .04), although this outcome was not uniformly reported and fertility or rate of pregnancy was not the primary outcome in any of the trials. CONCLUSIONS AND RELEVANCE Gonadotropin-releasing hormone agonists given with chemotherapy was associated with increased rates of recovery of regular menses in this meta-analysis. Evidence was insufficient to assess outcomes related to GnRHa and ovarian function and fertility and needs further investigation.216573Astra-Zenec
Temporal dynamics of the shrub and herbaceous layer of an area of moist grassland in Alto ParaÃso de Goiás, Brazil
Este trabalho avaliou a dinâmica estrutural e fl orÃstica de uma comunidade de espécies herbáceo-arbustivas
de uma área de campo limpo úmido em Alto ParaÃso de Goiás, o primeiro inventário realizado em 2000 (T0) e o
segundo em 2007 (T1). A diversidade de Shannon entre os perÃodos foi comparada pelo teste-t de Hutcheson e a
similaridade fl orÃstica, pelo Ãndice de similaridade de Chao-Sørensen. As relações fl orÃsticas e a cobertura, entre os
perÃodos e as linhas, foram avaliadas por meio de análises de correspondência retifi cada (DCA). Foram amostradas
98 espécies, 88 no T0 e 67 no T1, sendo 31 exclusivas do T0 e 10 do T1. A diversidade fl orÃstica na comunidade
foi elevada nos dois perÃodos, porém diferente entre esses (t = 7,12; p < 0,001), devido a variação no número e
cobertura das espécies. A similaridade entre os dois inventários foi alta (Chao-Sørensen ± IC = 0,841 ± 0,074). A
ordenação por DCA indicou relações entre a composição fl orÃstica e a cobertura com o gradiente de umidade e
de matéria orgânica no solo identifi cados em T0. Houve modifi cações nas linhas em zonas sazonais, as quais se
tornaram mais semelhantes às linhas constantemente saturadas por água. Em um intervalo de sete anos o campo
limpo úmido apresentou mudanças na composição fl orÃstica e, principalmente na estrutura devido o aumento da
cobertura de espécies perenes, cespitosas e entouceiradas, que foram favorecidas pela maior umidade no solo em
resposta à elevação da pluviosidade da região. __________________________________________________________________________________________ ABSTRACTTh is study evaluated the fl oristic and structural dynamics of a community of herbaceous-shrub species
in an area of moist grassland in Alto ParaÃso de Goiás. Th e fi rst inventory was undertaken in 2000 (T0) and the
second in 2007 (T1). Shannon’s diversity between the periods was compared by Hutchesons´s t-test, and the
fl oristic similarity by the Chao-Sørensen similarity index. Floristic composition and cover, between periods and
lines, were evaluated by detrended correspondence analysis (DCA). We sampled 98 species, 88 at T0 and 67 at T1;
31 were unique to T0 and 10 to T1. Floristic diversity in the community was high in both periods, but diff erent
between them (t = 7.12, p <0.001), due to variation in species number and coverage. Similarity between the two
surveys was high (Chao-Sørensen CI = ± 0.841 ± 0.074). Th e DCA ordination indicated relationships between the
fl oristic composition and cover with a gradient of moisture and organic matter in the soil identifi ed in T0. Th ere
were changes in the lines in the seasonal zones, which became more similar in those constantly saturated with
water. During an interval of seven years the moist grassland showed changes in fl oristic composition and mainly
in structure due to increased cover of the clumped tussock perennial species, which were favored by higher soil
moisture due to high rainfall in the region
Antideuteron yield at the AGS and coalescence implications
We present Experiment 864's measurement of invariant antideuteron yields in
11.5A GeV/c Au + Pt collisions. The analysis includes 250 million triggers
representing 14 billion 10% central interactions sampled for events with high
mass candidates. We find (1/2 pi pt) d^(2)N/dydpt = 3.5 +/- 1.5 (stat.)
+0.9,-0.5 (sys.) x 10^(-8) GeV^(-2)c^(2) for 1.8=0.35 GeV/c
(y(cm)=1.6) and 3.7 +/- 2.7 (stat.) +1.4,-1.5 (sys.) x 10^(-8) GeV^(-2)c^(2)
for 1.4=0.26 GeV/c, and a coalescence parameter B2-bar of 4.1 +/-
2.9 (stat.) +2.3,-2.4 (sys.) x 10^(-3) GeV^(2)c^(-3). Implications for the
coalescence model and antimatter annihilation are discussed.Comment: 8 pages, 4 figures, Latex, submitted to Phys. Rev. Let
Percepção da qualidade do leite pelo consumidor no municÃpio de Dom Pedrito no estado do Rio Grande do Sul.
Mass dependence of light nucleus production in ultrarelativistic heavy ion collisions
Light nuclei can be produced in the central reaction zone via coalescence in
relativistic heavy ion collisions. E864 at BNL has measured the production of
ten light nuclei with nuclear number of A=1 to A=7 at rapidity and
. Data were taken with a Au beam of momentum of 11.5 A
on a Pb or Pt target with different experimental settings. The
invariant yields show a striking exponential dependence on nuclear number with
a penalty factor of about 50 per additional nucleon. Detailed analysis reveals
that the production may depend on the spin factor of the nucleus and the
nuclear binding energy as well.Comment: (6 pages, 3 figures), some changes on text, references and figures'
lettering. To be published in PRL (13Dec1999
Measurements of Light Nuclei Production in 11.5 A GeV/c Au+Pb Heavy-Ion Collisions
We report on measurements by the E864 experiment at the BNL-AGS of the yields
of light nuclei in collisions of Au(197) with beam momentum of 11.5 A GeV/c on
targets of Pb(208) and Pt(197). The yields are reported for nuclei with baryon
number A=1 up to A=7, and typically cover a rapidity range from y(cm) to
y(cm)+1 and a transverse momentum range of approximately 0.1 < p(T)/A < 0.5
GeV/c. We calculate coalescence scale factors B(A) from which we extract model
dependent source dimensions and collective flow velocities. We also examine the
dependences of the yields on baryon number, spin, and isospin of the produced
nuclei.Comment: 21 figures-to be published in Phys. Rev.
Antiproton Production in 11.5 A GeV/c Au+Pb Nucleus-Nucleus Collisions
We present the first results from the E864 collaboration on the production of
antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the
Brookhaven AGS. We report invariant multiplicities for antiproton production in
the kinematic region 1.4<y<2.2 and 50<p_T<300 MeV/c, and compare our data with
a first collision scaling model and previously published results from the E878
collaboration. The differences between the E864 and E878 antiproton
measurements and the implications for antihyperon production are discussed.Comment: 4 pages, 4 figures; accepted for publication in Physical Review
Letter
Impactos ambientais da implantação do sistema de produção agroecológica integrada e sustentável (PAIS) em unidades familiares do Distrito Federal.
- …