Detection of Spiral photons in Quantum Optics

We show that a new type of photon detector, sensitive to the gradients of electromagnetic fields, should be a useful tool to characterize the quantum properties of spatially-dependent optical fields. As a simple detector of such a kind, we propose using magnetic dipole or electric quadrupole transitions in atoms or molecules and apply it to the detection of spiral photons in Laguerre-Gauss (LG) beams. We show that LG beams are not true hollow beams, due to the presence of magnetic fields and gradients of electric fields on beam axis. This approach paves the way to an analysis at the quantum level of the spatial structure and angular momentum properties of singular light beams.Comment: 5 pages, 4 figure

The Role of BAR Proteins and the Glycocalyx in Brain Endothelium Transcytosis

Within the brain, endothelial cells lining the blood vessels meticulously coordinate the transport of nutrients, energy metabolites and other macromolecules essential in maintaining an appropriate activity of the brain. While small molecules are pumped across specialised molecular transporters, large macromolecular cargos are shuttled from one side to the other through membrane-bound carriers formed by endocytosis on one side, trafficked to the other side and released by exocytosis. Such a process is collectively known as transcytosis. The brain endothelium is recognised to possess an intricate vesicular endosomal network that mediates the transcellular transport of cargos from blood-to-brain and brain-to-blood. However, mounting evidence suggests that brain endothelial cells (BECs) employ a more direct route via tubular carriers for a fast and efficient transport from the blood to the brain. Here, we compile the mechanism of transcytosis in BECs, in which we highlight intracellular trafficking mediated by tubulation, and emphasise the possible role in transcytosis of the Bin/Amphiphysin/Rvs (BAR) proteins and glycocalyx (GC)-a layer of sugars covering BECs, in transcytosis. Both BAR proteins and the GC are intrinsically associated with cell membranes and involved in the modulation and shaping of these membranes. Hence, we aim to summarise the machinery involved in transcytosis in BECs and highlight an uncovered role of BAR proteins and the GC at the brain endothelium

Specific heat amplitude ratios for anisotropic Lifshitz critical behaviors

We determine the specific heat amplitude ratio near a $m$-axial Lifshitz point and show its universal character. Using a recent renormalization group picture along with new field-theoretical $\epsilon_{L}$-expansion techniques, we established this amplitude ratio at one-loop order. We estimate the numerical value of this amplitude ratio for $m=1$ and $d=3$. The result is in very good agreement with its experimental measurement on the magnetic material $MnP$. It is shown that in the limit $m \to 0$ it trivially reduces to the Ising-like amplitude ratio.Comment: 8 pages, RevTex, accepted as a Brief Report in Physical Review

Potencial agrícola do solo para o cultivo da cebola.

No Nordeste, o cultivo da cebola é realizado durante o ano todo, com concentração de plantio nos meses de janeiro a março e colheitas de maio a julho (120 dias), para atender à demanda dos mercados consumidores das regiões Sul e Sudeste

Potencial agrícola do solo para cultivo da melancia.

A cultura da melancia tem grande importância socio-econômica no Nordeste brasileiro, por ser cultivada principalmente por pequenos agricultores, sob condições irrigadas e de chuva, devido ao seu fácil manejo e menor custo de produção, quando comparada a outras hortaliças

Potencial agrícola do solo para o cultivo da melancia.

A melancia (Citrullus lanatus (Thunb.)Matsum & nakai), pertence à família das cucurbitáceas, sendo originária do continente africano. É uma planta anual, de crescimento rasteiro, com várias ramificações que alcançam até 5 m de comprime nto. É cultivada em vários países do mundo, com uma produção total de, aproximadamente, 47 milhões de toneladas de frutos (Doorenbos & Kassam, 1994). No Brasil segundo dados Agrianual (2004), a área plantada em 2000 superou 80.000 ha, com produção total de 2.267.880 toneladas de frutos e rendimento da ordem de 28 t/ha, sendo o Nordeste responsável por 35,17% dessa produção destacando-se os Estados da Bahia (427.720 t),. Pernambuco (122.360 t) e Maranhão (94.020 t). A cultura da melancia tem grande importância socio-econômica no Nordeste brasileiro, por ser cultivada principalmente por pequenos agricultores, sob condições irrigadas e de chuva, devido ao seu fácil manejo e menor custo de produção, quando comparada a outras hortaliças

Anisotropic Lifshitz Point at O(ϵL2)O(\epsilon_L^2)

We present the critical exponents $\nu_{L2}$, $\eta_{L2}$ and $\gamma_{L}$ for an $m$-axial Lifshitz point at second order in an $\epsilon_{L}$ expansion. We introduced a constraint involving the loop momenta along the $m$-dimensional subspace in order to perform two- and three-loop integrals. The results are valid in the range $0 \leq m < d$. The case $m=0$ corresponds to the usual Ising-like critical behavior.Comment: 10 pages, Revte