On an extremal problem for poset dimension

Let $f(n)$ be the largest integer such that every poset on $n$ elements has a $2$-dimensional subposet on $f(n)$ elements. What is the asymptotics of $f(n)$? It is easy to see that $f(n)\geqslant n^{1/2}$. We improve the best known upper bound and show $f(n)=\mathcal{O}(n^{2/3})$. For higher dimensions, we show $f_d(n)=\mathcal{O}\left(n^\frac{d}{d+1}\right)$, where $f_d(n)$ is the largest integer such that every poset on $n$ elements has a $d$-dimensional subposet on $f_d(n)$ elements.Comment: removed proof of Theorem 3 duplicating previous work; fixed typos and reference

TELLUS: A combined surface temperature, soil moisture and evaporation mapping approach

There are no author-identified significant results in this report

Estimating the development of landrace and improved maize cultivars as a function of air temperature.

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Resposta de cordeiros ao parasitismo por Haemonchus contortus previamente infectados com Haemonchus placei.

Com o objetivo de verificar a resposta de cordeiros ao parasitismo por Haemonchus contortus após a primo-infecção com H. placei foi realizado o presente estudo em 39 ovinos divididos em quatro grupos: grupo HCC (controle positivo, primo-infectado com H. contortus e desafiado com H. contortus); HCP (primo-infectado com H. contortus e desafiado com H. placei); HPC (primo-infectado com H. placei e desafiados com H. contortus) e CNE (controle negativo). Os animais foram avaliados através da contagem de ovos por grama de fezes (OPG), carga parasitária e contagem total de leucócitos. Os resultados mostraram que a média da carga parasitária e da contagem total de leucócitos não apresentaram diferença (P > 0,05) entre os grupos. A média de OPG do grupo HCP foi menor em relação aos grupos HCC e HPC (P < 0,05). Os resultados obtidos até o momento mostram que a primo-infecção com H. placei não é capaz de reduzir os níveis de OPG de subsequentes infecções por H. contortus

The PS complex produces the nominal LHC beam

The LHC [1] will be supplied, via the SPS, with protons from the pre-injector chain comprising Linac2, PS Booster (PSB) and PS. These accelerators have under-gone a major upgrading programme [2] during the last five years so as to meet the stringent requirements of the LHC. These imply that many high-intensity bunches of small emittance and tight spacing (25 ns) be available at the PS extraction energy (25 GeV). The upgrading project involved an increase of Linac2 current, new RF systems in the PSB and the PS, raising the PSB energy from 1 to 1.4 GeV, two-batch filling of the PS and the installation of high-resolution beam profile measurement devices. With the project entering its final phase and most of the newly installed hardware now being operational, the emphasis switches to producing the nominal LHC beam and tackling the associated beam physics problems. While a beam with transverse characteristics better than nominal has been obtained, the longitudinal density still needs to be increased. An alternative scheme to produce the 25 ns bunch spacing is outlined, together with other promising developments

Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific

Background: In the southeastern tropical Pacific anchovy (Engraulis ringens) and sardine (Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world's most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences. Methodology/Principal Findings: A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem. Conclusions/Significance: For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems