Implementation and Performance Analysis of a Low Resolution OFDM System Prototype With Low Cost Hardware

The present work focus on the implementation and analyze of performance of a low-resolution OFDM system prototype with low-cost hardware. A software defined radio (SDR) system was chosen in this implementation due to its various advantages over a traditional radio system. Among the options of SDR devices available, the use of universal software radio peripherals (USRP) was avoided due to its high cost, despite its popularity in this field of research. Alternatively, a combination of two low-cost SDRs, "Hackrf One" and "RTL- SDR Blog V3" with the GNU Radio, a popular, free and open source radio software, were used. Thus, it was possible to emulate the behavior of a low resolution ADC in the receiver, characterize its performance and estimate its energy savings. This allowed us to determine the feasibility of building a component with the analog-to-digital conversion function with few bits of resolution. We conclude that the performance of an ADC with at least 5 bits of resolution is pretty reasonable and that this reduction in the number of bits, in comparison to 8-bit ADC, represents a fairly expressive energy saving

Improving irrigation management based on canopy-atmosphere coupling.

Os grandes avanços nas tecnologias de irrigação não foram acompanhados pelo manejo de irrigação na maior parte das áreas irrigadas. A falta de informações básicas sobre as necessidades hídricas das culturas é uma das razoes para uso inadequada da água de irrigação. Uma das abordagens normalmente utilizadas para quantificar o uso consultivo de água em culturas irrigadas é através da abordagem baseada na estimativa da evapotranspiração de referencia (ETo) em associação com o coeficiente de cultivo (Kc) para estimativa da evapotranspiração máxima do cultivo (ETc). Neste trabalho utilizou-se dados de cinco culturas (café, citros, cana-de-açúcar, milho e soja) para discutir o paradigma do Kc e sua relação com a ETo. Com exceção da cultura da soja, observou-se que o Kc decresce com a ETo devido às elevadas resistências internas da planta, que limita o transporte de massa do sistema vegetal para a atmosfera. Para cana-de-açúcar e milho, mesmo após a completa cobertura do solo pela cultura, Kc também decresceu com a ETo, destacando que essa tendência não é exclusiva de culturas de grande porte e esparsas como nos pomares de citros e cafeeiros. Apenas os dados oriundos na cultura da soja mostraram acoplamento copa-atmosfera relativamente inferior em comparação com as demais culturas, indicando a necessidade de se computar o fator de desacoplamento copa-atmosfera para a melhoria do manejo da irrigação em culturas agrícolas

Leaf-, panel- and latex-expressed sequenced tags from the rubber tree (Hevea brasiliensis) under cold-stressed and suboptimal growing conditions: the development of gene-targeted Functional markers for stress response.

Hevea brasiliensis is a native species of the Amazon Basin of South America and the primary source of natural rubber worldwide. Due to the occurrence of South American Leaf Blight disease in this area, rubber plantations have been extended to suboptimal regions. Rubber tree breeding is time-consuming and expensive, but molecular markers can serve as a tool for early valuation, thus reducing time and costs. In this work, we constructed six different cDNA libraries with the aim of developing gene-targeted molecular markers for the rubber tree. A total of 8,263 reads were assembled, generating 5,025 unigenes that were analyzed; 912 expressed sequence tags (ESTs) represented new transcripts, and two sequences were highly up-regulated by cold stress. These unigenes were scanned for microsatellite (SSR) regions and single nucleotide polymorphisms (SNPs). In total, 169 novel EST-SSR markers were developed; 138 loci were polymorphic in the rubber tree, and 98 % presented transferability to six other Hevea species. Locus duplication was observed in H. brasil-iensis and other species. Additionally, 43 SNP markers in 13 sequences that showed similarity to proteins involved in stress response, latex biosynthesis and developmental processes were characterized. cDNA libraries are a rich source of SSR and SNP markers and enable the identification of new transcripts. The new markers developed here will be a valuable resource for linkage mapping, QTL identification and other studies in the rubber tree and can also be used to evaluate the genetic variability of other Hevea species, which are valuable assets in rubber tree breeding

tert-Butyl 2-{[2,8-bis­(trifluoro­meth­yl)quinolin-4-yl](hy­droxy)meth­yl}piperidine-1-carboxyl­ate

The title mol­ecule, C22H24F6N2O3, adopts a folded conformation whereby the carboxyl­ate residue lies over the quinolinyl residue, with the dihedral angle between the carbamate and quinoline planes being 41.64 (7)°. Helical supra­molecular C(7) chains sustained by O—H⋯O hydrogen bonds propagating along the a-axis direction feature in the crystal packing. The F atoms of one of the CF3 groups are disordered over two orientations; the major component has a site occupancy of 0.824 (7)

Benzyl 2-{[2,8-bis­(trifluoro­meth­yl)quinolin-4-yl](hy­droxy)meth­yl}piperidine-1-carboxyl­ate

The title mol­ecule, C25H22F6N2O3, adopts an open conformation whereby the quinoline and carboxyl­ate ester groups are orientated in opposite directions but to the same side of the piperidine ring so that the mol­ecule has an approximate U-shape. The piperidine ring adopts a distorted boat conformation. In the crystal, inversion dimers linked by pairs of O—H⋯O hydrogen bonds generate R 2 2(14) loops

2-{1-[2,8-Bis(trifluoro­meth­yl)quinolin-4-yl]-3,5,6,7,8,8a-hexa­hydro-1H-1,3-oxazolo[3,4-a]pyridin-3-yl}phenol

In the title mefloquine–oxazolidine derivative, C24H20F6N2O2, the oxazoline ring adopts an envelope conformation (the flap atom is N) and the piperidine ring has a chair conformation. The oxazoline and benzene residues lie away from the C6 ring of the quinoline group and, to a first approximation, to one side of the plane through the ten atoms (r.m.s. deviation = 0.025 Å). An intra­molecular O—H⋯N(piperidine) hydrogen bond is present. The crystal packing features C—H⋯O, C—H⋯F and C—H⋯π(hy­droxy­benzene) inter­actions

(R*,S*)-(±)-1-(2-{[2,8-Bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-yl)ethanone methanol monosolvate

The title mefloquine derivative has been crystallized as its 1:1 methanol solvate, C19H18F6N2O2·CH3OH. Each of the meth­ine­hydroxyl residue [the C—C—C—O torsion angle is −16.35 (17) °] and the piperidinyl group [distorted chair conformation] lies to one side of the quinolinyl ring system. The hydroxyl and carbonyl groups lie to either side of the mol­ecule, enabling their participation in inter­molecular inter­actions. Thus, the hydroxyl and carbonyl groups of two centrosymmetrically related mol­ecules are bridged by two methanol mol­ecules via O—H⋯O hydrogen bonds, leading to a four-mol­ecule aggregate. These are linked into a supra­molecular chain along the a axis via C—H⋯O inter­actions involving the hydroxyl-O atom. The chains assemble into layers that inter­digitate along the c axis being connected by C—H⋯F inter­actions