BRESEX: On board supervision, basic architecture and preliminary aspects for payload and space shuttle interface

Data relative to the on board supervision subsystem are presented which were considered in a conference between INPE and NASA personnel, with the purpose of initiating a joint effort leading to the implementation of the Brazilian remote sensing experiment - (BRESEX). The BRESEX should consist, basically, of a multispectral camera for Earth observation, to be tested in a future space shuttle flight

Neutral heavy lepton production at next high energy e+e−e^+e^- linear colliders

The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process $e^+e^- \longrightarrow {\nu} e^{\pm} W^{\mp}$ is calculated including on-shell and off-shell heavy neutrino effects. We present a detailed study of cross sections and distributions that shows a clear separation between the signal and standard model contributions, even after including hadronization effects.Comment: 4 pages including 15 figures, 1 table. RevTex. Accepted in Physical Review

Quantum Logic with a Single Trapped Electron

We propose the use of a trapped electron to implement quantum logic operations. The fundamental controlled-NOT gate is shown to be feasible. The two quantum bits are stored in the internal and external (motional) degrees of freedom.Comment: 7 Pages, REVTeX, No Figures, To appear in Phys. Rev.

Electron-radiation interaction in a Penning trap: beyond the dipole approximation

We investigate the physics of a single trapped electron interacting with a radiation field without the dipole approximation. This gives new physical insights in the so-called geonium theory.Comment: 12 pages, RevTeX, 6 figures, Approved for publication in Phys. Rev.

A reaction-diffusion model for the growth of avascular tumor

A nutrient-limited model for avascular cancer growth including cell proliferation, motility and death is presented. The model qualitatively reproduces commonly observed morphologies for primary tumors, and the simulated patterns are characterized by its gyration radius, total number of cancer cells, and number of cells on tumor periphery. These very distinct morphological patterns follow Gompertz growth curves, but exhibit different scaling laws for their surfaces. Also, the simulated tumors incorporate a spatial structure composed of a central necrotic core, an inner rim of quiescent cells and a narrow outer shell of proliferating cells in agreement with biological data. Finally, our results indicate that the competition for nutrients among normal and cancer cells may be a determinant factor in generating papillary tumor morphology.Comment: 9 pages, 6 figures, to appear in PR

Signature for heavy Majorana neutrinos in hadronic collisions

The production and decay of new possible heavy Majorana neutrinos are analyzed in hadronic collisions. New bounds on the mixing of these particles with standard neutrinos are estimated according to a fundamental representation suggested by grand unified models. A clear signature for these Majorana neutrinos is given by same-sign dileptons plus a charged weak vector boson in the final state. We discuss the experimental possibilities for the future Large Hadron Collider (LHC) at CERN.Comment: Latex2e(epsfig), 12 pages, 8 figures, to appear Physical Review

Phosphoproteomic differences in major depressive disorder postmortem brains indicate effects on synaptic function

There is still a lack in the molecular comprehension of major depressive disorder (MDD) although this condition affects approximately 10% of the world population. Protein phosphorylation is a posttranslational modification that regulates approximately one-third of the human proteins involved in a range of cellular and biological processes such as cellular signaling. Whereas phosphoproteome studies have been carried out extensively in cancer research, few such investigations have been carried out in studies of psychiatric disorders. Here, we present a comparative phosphoproteome analysis of postmortem dorsolateral prefrontal cortex tissues from 24 MDD patients and 12 control donors. Tissue extracts were analyzed using liquid chromatography mass spectrometry in a data-independent manner (LC-MSE). Our analyses resulted in the identification of 5,195 phosphopeptides, corresponding to 802 non-redundant proteins. Ninety of these proteins showed differential levels of phosphorylation in tissues from MDD subjects compared to controls, being 20 differentially phosphorylated in at least 2 peptides. The majority of these phosphorylated proteins were associated with synaptic transmission and cellular architecture not only pointing out potential biomarker candidates but mainly shedding light to the comprehension of MDD pathobiology

Chiral Polymerization in Open Systems From Chiral-Selective Reaction Rates

We investigate the possibility that prebiotic homochirality can be achieved exclusively through chiral-selective reaction rate parameters without any other explicit mechanism for chiral bias. Specifically, we examine an open network of polymerization reactions, where the reaction rates can have chiral-selective values. The reactions are neither autocatalytic nor do they contain explicit enantiomeric cross-inhibition terms. We are thus investigating how rare a set of chiral-selective reaction rates needs to be in order to generate a reasonable amount of chiral bias. We quantify our results adopting a statistical approach: varying both the mean value and the rms dispersion of the relevant reaction rates, we show that moderate to high levels of chiral excess can be achieved with fairly small chiral bias, below 10%. Considering the various unknowns related to prebiotic chemical networks in early Earth and the dependence of reaction rates to environmental properties such as temperature and pressure variations, we argue that homochirality could have been achieved from moderate amounts of chiral selectivity in the reaction rates.Comment: 15 pages, 6 figures, accepted for publication in Origins of Life and Evolution of Biosphere

Study of 16 Portuguese activated sludge systems based on filamentous bacteria populations and their relationships with environmental parameters

A survey in 16 activated sludge waste water treatment plants (WWTP) was conducted to contribute to the knowledge of the environmental parameters that determine the composition of the filamentous community. A total of 128 samples of mixed liquor from municipal WWTP were collected during 2 years, and 22 filamentous morphotypes were identified. The most frequent and abundant filamentous bacteria were, in both cases and by this order, type 0041/0675, type 0092, Microthrix parvicella and 1851, nocardioforms and Haliscomenobacter hydrossis. Concerning dominance, type 1851 was the most frequently dominant morphotype, followed by M. parvicella and types 0092 and 0041/0675. These were also, and by this order, the dominant morphotypes during bulking occurrences. Significant correlations were obtained between the abundance of filamentous bacteria and environmental parameters, but multivariate statistical analysis only confirmed the correlation between type 0092 and Sludge Volume Index (SVI), emphasizing the association of this filament with bulking. The discussion of the results in light of published works was complicated by the random use of terms such as frequency, abundance, and dominance with different and often unclear meanings. This reinforces the need of clarifying these terms when discussing the causes of filamentous overgrowth in WWTP.Portuguese Foundation for Science and Technology (FCT) and the European Community fund FEDER, through Program COMPETE, in the ambit of the Projects FCOMP-01-0124-FEDER-007025 (PTDC/AMB/68393/2006), PEst-OE/EQB/LA0023/2013, RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and the Project BBioEnv - Biotechnology and Bioengineering for a sustainable world,REF. NORTE-07-0124- FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. PhD grant SFRH/BD/64848/200

Field-induced Ordering in Critical Antiferromagnets

Transfer-matrix scaling methods have been used to study critical properties of field-induced phase transitions of two distinct two-dimensional antiferromagnets with discrete-symmetry order parameters: triangular-lattice Ising systems (TIAF) and the square-lattice three-state Potts model (SPAF-3). Our main findings are summarised as follows. For TIAF, we have shown that the critical line leaves the zero-temperature, zero -field fixed point at a finite angle. Our best estimate of the slope at the origin is $(dT_c/dH)_{T=H=0} = 4.74 \pm 0.15$. For SPAF-3 we provided evidence that the zero-field correlation length diverges as $\xi(T \to 0, H=0) \simeq \exp (a/T^{x})$, with $x=1.08 \pm 0.13$, through analysis of the critical curve at $H \neq 0$ plus crossover arguments. For SPAF-3 we have also ascertained that the conformal anomaly and decay-of-correlations exponent behave as: (a) H=0: $c=1, \eta=1/3$; (b) $H \neq 0: c=1/2, \eta=1/4$.Comment: RevTex, 7 pages, 4 eps figures, to be published in Phys. Rev.