1,257 research outputs found

    A numerical study of the ocean circulation around the northern Antarctic Peninsula: Barotropic response to tidal forcing

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    A high-resolution shallow water model was implemented to study tidal propagation around the northern Antarctic Peninsula. Numerical experiments were done using a grid with 3.00′longitude and 1.05′latitude resolution. Amplitudes and phases of the four main tidal constituents (M_2, S_2, K_1 and O_1) were used to force the model. Modeled sea levels and currents were compared with observations. The modeled cotidal, corange and tidal ellipse axis obtained by harmonic analysis from model results are in good agreement with those of available observations. Given the good correspondence between harmonic constants obtained from model results and from observed hourly sea levels, the energy flux and dissipation by bottom friction were computed. The most intense energy fluxes are related to the semidiurnal constituents. The highest values are present in the Weddell Sea and the energy flux shows a relative maximum at the Antarctic Strait, flowing from the Weddell Sea to Bransfield Strait. Nearly all the dissipation occurs in the Antarctic Strait (maximum value ~0.25Wm^(-2)) and around the South Shetland Islands. The total tidal energy lost to bottom friction in our 4-constituent model is about 1.5GW, giving a domain-averaged value of ~0.002Wm^(-2)

    Propagation and amplification of tide at the northeastern coast of the Antarctic peninsula: an observational study

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    The amplification and propagation of the tide at the northeastern coast of the Antarctic Peninsula was studied by analysis of instantaneous sea levels measured at the tidal station of Base Esperanza,at the northern end of the Antarctic Peninsula (63゜22.46\u27S, 56゜59.33\u27W) ,at the northeastern coast of Marambio Island (Seymour Island,64゜14.11\u27S, 56゜34.51\u27W) and near Base Matienzo,Larsen nunatak (64゜54.23\u27S, 60゜2.60\u27W) at the edge of the Larsen ice-shelf. By means of harmonic analysis the amplitudes and phases of the most energetic ten tidal constituents were obtained.The tidal regime was typified by means of the factor F and a preponderantly semidiurnal mixed tide was obtained. Signi ficant southward amplification was observed in the amplitudes of semidiurnal constituents,and a less evident amplification was obtained in diurnal ones.Consequently,slightly southward diminution in factor F,from 0.75 (Esperanza) to 0.6 (Matienzo),was found.Bothsouthward amplification in amplitudes and northward propagation of the main tidal constituents obtained from numerical global models show good agreement with the present observations

    Propagation and amplification of tide at the Bransfield and Gerlache Straits, northwestern Antarctic Peninsula

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    The propagation and amplification of the tide at the Gerlache and Bransfield Straits, northwestern side of the Antarctic Peninsula, was studied by analysis of thirteen series of direct sea level measurements. Harmonic analysis was performed to obtain the amplitudes and phases of the M_2, S_2, O_1 and K_1 tidal constituents. Based on the computed harmonic constants, cotidal and corange charts of these main constituents were prepared. The M_2 cotidal lines are parallel to the coast and show predominantly southeastward propagation, except at the western side of the Trinity Peninsula, where the M_2 wave pivots to enter the Bransfield Strait from the Weddell Sea and turns southwestward. M_2 amplitudes present a southwestward decrease. S_2 cotidal lines are normal to the Antarctic Peninsula coast and show southwestward propagation. S_2 corange lines increase eastward from the Gerlache Strait to the Antarctic Strait. O_1 and K_1 cotidal lines are also normal to the Antarctic Peninsula coast. Diurnal amplitudes are alike in the study area except at the northwestern side of the Antarctic Strait where they present a maximum gradient. Amplitudes of the main tidal constituents are higher in the northwestern Weddell Sea than at the northwestern side of the peninsula. This fact explains the maximum tidal amplitudes observed at the Antarctic Strait in comparison to the Bransfield Strait

    Correlation between FIX genotype and pharmacokinetics of Nonacog alpha according to a multicentre Italian study

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    Pharmacokinetic (PK) studies on recombinant FIX concentrate, Nonacog alpha, were conducted with different sampling time designs which gave rise to not complete and homogenous outcomes. In addition, patient's FIX genotype/PK relationship has never been investigated

    Major milestones in translational oncology.

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    Translational oncology represents a bridge between basic research and clinical practice in cancer medicine. Today, translational research in oncology benefits from an abundance of knowledge resulting from genome-scale studies regarding the molecular pathways involved in tumorigenesis. In this Forum article, we highlight the state of the art of translational oncology in five major cancer types. We illustrate the use of molecular profiling to subtype colorectal cancer for both diagnosis and treatment, and summarize the results of a nationwide screening program for ovarian cancer based on detection of a tumor biomarker in serum. Additionally, we discuss how circulating tumor DNA can be assayed to safely monitor breast cancer over the course of treatment, and report on how therapy with immune checkpoint inhibitors is proving effective in advanced lung cancer. Finally, we summarize efforts to use molecular profiling of prostate cancer biopsy specimens to support treatment decisions. Despite encouraging early successes, we cannot disregard the complex genetics of individual susceptibility to cancer nor the enormous complexity of the somatic changes observed in tumors, which urge particular attention to the development of personalized therapies

    Genetic control of renal tumorigenesis by the mouse Rtm1 locus

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    BACKGROUND: The genetic basis of susceptibility to renal tumorigenesis has not yet been established in mouse strains. Mouse lines derived by bidirectional phenotypic selection on the basis of their maximal (AIRmax) or minimal (AIRmin) acute inflammatory responsiveness differ widely in susceptibility to spontaneous and urethane-induced renal tumorigenesis. To map the functional loci modulating renal tumor susceptibility in these mice, we carried out a genome-wide genetic linkage study, using SNP arrays, in an (AIRmax x AIRmin)F2 intercross population treated with a single urethane dose at 1 week of age and phenotyped for renal tumors at 35 weeks of age. RESULTS: AIRmax mice did not develop renal tumors spontaneously nor in response to urethane, whereas in AIRmin mice renal tumors formed spontaneously (in 52% of animals) and after urethane induction (89%). The tumors had a papillary morphology and were positive for alpha-methylacyl-CoA racemase and negative for CD10. By analysis of 879 informative SNPs in 662 mice, we mapped a single quantitative trait locus modulating the incidence of renal tumors in the (AIRmax x AIRmin)F2 intercross population. This locus, which we named Renal tumor modifier QTL 1 (Rtm1), mapped to chromosome 17 at 23.4 Mb (LOD score = 15.8), with SNPs rs3696835 and rs3719497 flanking the LOD score peak. The A allele of rs3719497 from AIRmin mice was associated with a 2.5-fold increased odds ratio for renal tumor development. The LOD score peak included the Tuberous sclerosis 2 (Tsc2) gene which has already been implicated in kidney disease: loss of function by germline retroviral insertion is associated with spontaneous renal tumorigenesis in the Eker rat, and heterozygous-null Tsc2((+/-)) mice develop renal cystadenomas. CONCLUSIONS: We mapped Rtm1 as a single major locus modulating renal tumorigenesis in a murine intercross population. Thus, the AIR mouse lines can be considered a new genetic model for studying the role of germline and somatic molecular alterations in kidney neoplastic disease

    Spectral variability in high frequency in sea level and atmospheric pressure on Buenos Aires Coast, Argentina

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    Existem evidências observacionais que apoiam a ideia de que as ondas de gravidade atmosféricas são um forçante eficiente para os tsunamis meteorológicos (meteotsunamis) na região da costa da província de Buenos Aires, Argentina. Os meteotsunamis e as ondas de gravidade atmosférica que se propagam simultaneamente na superfície do mar e na atmosfera, respectivamente, são exemplos típicos de sinais geofísicos não estacionários. Neste trabalho investiga-se a variabilidade de meteotsunamis e de ondas de gravidade atmosférica medidas em Mar del Plata. Os resultados obtidos mostram que os ondeletas para os meteotsunamis e as ondas de gravidade são relativamente semelhantes. Isso reforça a ideia da relação causa (ondas de gravidade atmosférica) efeito (meteotsunamis) entre ambos. No entanto, vários episódios muito curtos de moderada a baixa atividade de ondas de gravidade atmosféricas foram detectados sem detectar atividade meteotsunami. Por outro lado, encontrou-se que a energia espectral das ondas de gravidade atmosférica pode aparecer nos ondeletas como uma simples ou múltipla irrupção, como eventos irregulares relativamente longos, ou como pacotes de ondas regulares. Os resultados obtidos neste trabalho proporcionam informação espectral sobre as ondas de gravidade atmosférica na região costeira da província de Buenos Aires. Esta informação poderia ser útil para incluí-la em modelos numéricos realistas, com o objetivo de investigar a gênese desta complexa interação oceano-atmosfera.There are some observational evidences which support that atmospheric gravity waves constitute an efficient forcing for meteorological tsunamis (meteotsunamis) along the coast of Buenos Aires, Argentina. Meteotsunamis and atmospheric gravity waves, which propagate simultaneously on the sea surface and the atmosphere, respectively, are typical examples of non-stationary geophysical signals. The variability of meteotsunamis and atmospheric gravity waves recorded at Mar del Plata was investigated in this paper. Results obtained in this work reinforce the idea of a cause (atmospheric gravity waves) effect (meteotsunami) relationship, because wavelet spectra obtained from both signals resulted quite similar. However, several very short episodes of mod-erate/low activity of atmospheric gravity waves were detected without detecting meteotsunami activity. On the other hand, it was found that atmospheric gravity wave spectral energy can appear in the wavelets as a single or multiple burst as relatively long and irregular events or as regular wave packets. Results obtained in this paper provide original spectral data about atmospheric gravity waves along the coast of Buenos Aires. This information is useful to be included in realistic numerical models in order to investigate the genesis of this complex atmosphere-ocean interaction

    Assessment of upper tropospheric and stratospheric water vapor and ozone in reanalyses as part of S-RIP

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    Reanalysis data sets are widely used to understand atmospheric processes and past variability, and are often used to stand in as “observations” for comparisons with climate model output. Because of the central role of water vapor (WV) and ozone (O3) in climate change, it is important to understand how accurately and consistently these species are represented in existing global reanalyses. In this paper, we present the results of WV and O3 intercomparisons that have been performed as part of the SPARC (Stratosphere–troposphere Processes and their Role in Climate) Reanalysis Intercomparison Project (S-RIP). The comparisons cover a range of timescales and evaluate both inter-reanalysis and observation-reanalysis differences. We also provide a systematic documentation of the treatment of WV and O3 in current reanalyses to aid future research and guide the interpretation of differences amongst reanalysis fields. The assimilation of total column ozone (TCO) observations in newer reanalyses results in realistic representations of TCO in reanalyses except when data coverage is lacking, such as during polar night. The vertical distribution of ozone is also relatively well represented in the stratosphere in reanalyses, particularly given the relatively weak constraints on ozone vertical structure provided by most assimilated observations and the simplistic representations of ozone photochemical processes in most of the reanalysis forecast models. However, significant biases in the vertical distribution of ozone are found in the upper troposphere and lower stratosphere in all reanalyses
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