5,346 research outputs found
Mach-Zehnder interferometry with interacting trapped Bose-Einstein condensates
We theoretically analyze a Mach-Zehnder interferometer with trapped
condensates, and find that it is surprisingly stable against the nonlinearity
induced by inter-particle interactions. The phase sensitivity, which we study
for number squeezed input states, can overcome the shot noise limit and be
increased up to the Heisenberg limit provided that a Bayesian or
Maximum-Likelihood phase estimation strategy is used. We finally demonstrate
robustness of the Mach-Zehnder interferometer in presence of interactions
against condensate oscillations and a realistic atom counting error.Comment: 4 pages, 5 figures, minor revision
Loss of correlation between HIV viral load and CD4+ T-cell counts in HIV/HTLV-1 co-infection in treatment naive Mozambican patients
Seven hundred and four HIV-1/2-positive, antiretroviral therapy (ART) naïve patients were screened for HTLV-1 infection. Antibodies to HTLV-1 were found in 32/704 (4.5%) of the patients. Each co-infected individual was matched with two HIV mono-infected patients according to World Health Organization clinical stage, age +/-5 years and gender. Key clinical and laboratory characteristics were compared between the two groups. Mono-infected and co-infected patients displayed similar clinical characteristics. However, co-infected patients had higher absolute CD4+ T-cell counts (P = 0.001), higher percentage CD4+ T-cell counts (P < 0.001) and higher CD4/CD8 ratios (P < 0.001). Although HIV plasma RNA viral loads were inversely correlated with CD4+ T-cell-counts in mono-infected patients (P < 0.0001), a correlation was not found in co-infected individuals (P = 0.11). Patients with untreated HIV and HTLV-1 co-infection show a dissociation between immunological and HIV virological markers. Current recommendations for initiating ART and chemoprophylaxis against opportunistic infections in resource-poor settings rely on more readily available CD4+ T-cell counts without viral load parameters. These guidelines are not appropriate for co-infected individuals in whom high CD4+ T-cell counts persist despite high HIV viral load states. Thus, for co-infected patients, even in resource-poor settings, HIV viral loads are likely to contribute information crucial for the appropriate timing of ART introduction
Automated analysis of histological images by computational algorithms
The study of cellular tissues provides an incontestable source of information and comprehension about thehuman body and the surrounding environment. Accessing this information is, therefore, crucial to determineand diagnose a wide variety of pathologies detectable only at a microscopic scale. Hence, histology plays animportant role in the clinical diagnosis of pathologies involving abnormal cellular conformation. Inhistological images, semi- or automated segmentation algorithms are able to separate and identify cellularstructures according to morphological differences. The segmentation is usually the first task incomputational vision systems and, concerning histopathology, for the automated analysis of histologicalimages. Since the histological samples are thin, the volumetric features are almost unnoticeable,corresponding to losses of valuable information, mainly topographical and volumetric data, critical for acorrect analysis. Hence, the combination of segmentation and 3D reconstruction algorithms applied tohistological image datasets provides more information about the analyzed pathology and microscopicstructures, highlighting abnormal areas [1].In order to provide insights on pathological volumetric data, the present work focused on developing anautomatic computational solution for performing the 3D surface reconstruction of relevant tissue structurespresented in 2D histological slices. A state of the art technique, called stain deconvolution, was implementedto achieve color image segmentation providing an accurate segmentation of two different stains present inthe histological data: Hematoxylin and Eosin tissues. To register, i.e. align, the image slices presented in theinput datasets, an intensity based registration method was implemented, being the alignment performedbetween each slice in the input dataset and the reference slice (middle slice of the dataset). The datasetchosen for the previous alignment operation was the set of images obtained through the stain deconvolutionmethod for the hematoxylin stain. The transformation matrix obtained for each slice was then applied to theeosin stained images. The 3D reconstruction was implemented based on the Marching Cubes algorithm.Thus, combining algorithms of image segmentation and registration with of 3D surface reconstruction, itwas possible to obtain a volumetric representation of the pertinent tissue structures from the input imagedatasets. The experiments conducted revealed accurate and fast surface reconstructions of the differentstained tissues under study, highlighting the interesting structures and their volumetric interactions with thesurrounding healthy tissue
Phase Sensitivity of a Mach-Zehnder Interferometer
The best performance of a Mach-Zehnder interferometer is achieved with the
input state |N_T/2 + 1>|N_T/2-1 > + |N_T/2 - 1>|N_T/2+1>, being N_T the total
number of atoms/photons. This gives: i) a phase-shift error confidence
C_{68%}=2.67/N_T with ii) a single interferometric measurement. Different input
quantum states can achieve the Heisenberg scaling ~ 1/N_T but with higher
prefactors and at the price of a statistical analysis of two or more
independent measurements.Comment: 4 figure
Chiral Pharmaceutical Intermediaries Obtained by Reduction of 2-Halo-1-(4-substituted phenyl)-ethanones Mediated by Geotrichum candidum CCT 1205 and Rhodotorula glutinis CCT 2182
Enantioselective reductions of p-R1-C6H4C(O)CH2R2 (R1 = Cl, Br, CH3, OCH3, NO2 and R2 = Br, Cl) mediated by Geotrichum candidum CCT 1205 and Rhodotorula glutinis CCT 2182 afforded the corresponding halohydrins with complementary R and S configurations, respectively, in excellent yield and enantiomeric excesses. The obtained (R)- or (S)-halohydrins are important building blocks in chemical and pharmaceutical industries
Microbial Production Of Propionic And Succinic Acid From Sorbitol Using Propionibacterium Acidipropionici
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Three sequential fermentative batches were carried out with cell recycle in four simultaneously operating bioreactors maintained at pH 6.5, 30 degrees C, and 100 rpm. P. acidipropionici ATCC 4875 was able to produce propionic and succinic acid from sorbitol. The concentration of propionic acid decreased slightly from 39.5 +/- 5.2 g L-1 to 34.4 +/- 1.9 g L-1, and that of succinic acid increased significantly from 6.1 +/- 2.1 g L-1 to 14.8 +/- 0.9 g L-1 through the sequential batches. In addition, a small amount of acetic acid was produced that decreased from 3.3 +/- 0.4 g L-1 to 2.0 +/- 0.3 g L-1 through the batches. The major yield for propionic acid was 0.613 g g(-1) in the first batch and succinic acid it was 0.212 g g(-1) in the third batch. The minor yield of acetic acid was 0.029 g g(-1), in the second and third batches.5Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)BRASKEM S/AFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2011/51861-9
A coupled hydrodynamic and ecological model to manage water quality in Ria Formosa coastal lagoon
Nitrate and urban waste water directives have raised the need for a better understanding of coastal systems in the European Union. The incorrect application of these directives can lead to important ecological or social penalties. In this paper this problem is addressed to Ria Formosa Coastal Lagoon. Ria Formosa hosts a Natural Park, important ports of the southern Portuguese coast and significant bivalve aquaculture activity. Four major urban waste water treatment plants discharging into the lagoon are considered in this study. Its treatment level must be selected, based on. detailed information from a monitoring program and on a good knowledge of the processes determining the fate of the material discharged into the lagoon., In this paper the results of a monitoring program and simulations using a coupled hydrodynamic and water quality/ecological model, MOHID, are used to characterise the system and to understand the processes in Ria Formosa. It is shown that the water residence time in most of the. lagoon is quite low, of the order of days, but it can be larger in the upper parts of the channels where land generated water is discharged. The main supply of nutrients to the lagoon comes from the open sea rather than from the urban discharges. For this reason the characteristics and behaviour of the general lagoon contrasts with the behaviour of the upper reaches of the channels where the influence of the waste water treatment plants are high. In this system the bottom mineralization was found to be an important mechanism, and the inclusion of that process in the model was essential to obtain good results
Was the GLE on May 17, 2012 linked with the M5.1-class flare the first in the 24th solar cycle?
On May 17, 2012 an M5.1-class flare exploded from the sun. An O-type coronal
mass ejection (CME) was also associated with this flare. There was an instant
increase in proton flux with peak at MeV, leading to S2 solar
radiation storm level. In about 20 minutes after the X-ray emission, the solar
particles reached the Earth.It was the source of the first (since December
2006) ground level enhancement (GLE) of the current solar cycle 24. The GLE was
detected by neutron monitors (NM) and other ground based detectors. Here we
present an observation by the Tupi muon telescopes (Niteroi, Brazil, , , 3 m above sea level) of the enhancement of muons at ground
level associated with this M5.1-class solar flare. The Tupi telescopes
registered a muon excess over background in the 5-min binning time
profile. The Tupi signal is studied in correlation with data obtained by
space-borne detectors (GOES, ACE), ground based neutron monitors (Oulu) and air
shower detectors (the IceTop surface component of the IceCube neutrino
observatory). We also report the observation of the muon signal possibly
associated with the CME/sheath striking the Earth magnetosphere on May 20,
2012. We show that the observed temporal correlation of the muon excess
observed by the Tupi muon telescopes with solar transient events suggests a
real physical connection between them. Our observation indicates that
combination of two factors, the low energy threshold of the Tupi muon
telescopes and the location of the Tupi experiment in the South Atlantic
Anomaly region, can be favorable in the study and detection of the solar
transient events. Our experiment provides new data complementary to other
techniques (space and ground based) in the study of solar physics.Comment: 9 pages, 10 figure
Interactions and scattering of quantum vortices in a polariton fluid
Quantum vortices, the quantized version of classical vortices, play a
prominent role in superfluid and superconductor phase transitions. However,
their exploration at a particle level in open quantum systems has gained
considerable attention only recently. Here we study vortex pair interactions in
a resonant polariton fluid created in a solid-state microcavity. By tracking
the vortices on picosecond time scales, we reveal the role of nonlinearity, as
well as of density and phase gradients, in driving their rotational dynamics.
Such effects are also responsible for the split of composite spin-vortex
molecules into elementary half-vortices, when seeding opposite vorticity
between the two spinorial components. Remarkably, we also observe that vortices
placed in close proximity experience a pull-push scenario leading to unusual
scattering-like events that can be described by a tunable effective potential.
Understanding vortex interactions can be useful in quantum hydrodynamics and in
the development of vortex-based lattices, gyroscopes, and logic devices.Comment: 12 pages, 7 figures, Supplementary Material and 5 movies included in
arXi
- …