2,785 research outputs found
BENFORD’S LAW IN IMAGE PROCESSING
We present a generalization of Benford’s law for the first significant digit. This generalization is based on keeping two terms of the Fourier expansion of the probability density function of the data in the modular logarithmic domain. We prove that images in the Discrete Cosine Transform domain closely follow this generalization. We use this property to propose an application in image steganalysis, namely, detecting that a given image carries a hidden message
Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)
We present a study of the star-forming properties of a stellar mass-selected
sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space
Telescope imaging of the GOODS North and South fields. Using a stellar mass
selected sample, combined with HST/ACS and Spitzer data to measure both UV and
infrared derived star formation rates (SFR), we investigate the star forming
properties of a complete sample of ~1300 galaxies down to log M*=9.5 at
redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies
with M*>10^11 Msun. We derive optical colours, dust extinctions, and
ultraviolet and infrared SFR to determine how the star formation rate changes
as a function of both stellar mass and time. Our results show that SFR
increases at higher stellar mass such that massive galaxies nearly double their
stellar mass from star formation alone over the redshift range studied, but the
average value of SFR for a given stellar mass remains constant over this 2 Gyr
period. Furthermore, we find no strong evolution in the SFR for our sample as a
function of mass over our redshift range of interest, in particular we do not
find a decline in the SFR among massive galaxies, as is seen at z < 1. The most
massive galaxies in our sample (log M*>11) have high average SFRs with values,
SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at
all redshifts. We conclude that the majority of these red high-redshift massive
galaxies are red due to dust extinction. We find that A(2800) increases with
stellar mass, and show that between 45% and 85% of massive galaxies harbour
dusty star formation. These results show that even just a few Gyr after the
first galaxies appear, there are strong relations between the global physical
properties of galaxies, driven by stellar mass or another underlying feature of
galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA
A silicon-based single-electron interferometer coupled to a fermionic sea
We study Landau-Zener-Stueckelberg-Majorana (LZSM) interferometry under the
influence of projective readout using a charge qubit tunnel-coupled to a
fermionic sea. This allows us to characterise the coherent charge qubit
dynamics in the strong-driving regime. The device is realised within a silicon
complementary metal-oxide-semiconductor (CMOS) transistor. We first read out
the charge state of the system in a continuous non-demolition manner by
measuring the dispersive response of a high-frequency electrical resonator
coupled to the quantum system via the gate. By performing multiple fast
passages around the qubit avoided crossing, we observe a multi-passage LZSM
interferometry pattern. At larger driving amplitudes, a projective measurement
to an even-parity charge state is realised, showing a strong enhancement of the
dispersive readout signal. At even larger driving amplitudes, two projective
measurements are realised within the coherent evolution resulting in the
disappearance of the interference pattern. Our results demonstrate a way to
increase the state readout signal of coherent quantum systems and replicate
single-electron analogues of optical interferometry within a CMOS transistor
A Afetividade a Partir de uma Perspectiva da Subjetividade
The theoretical elaborations presented by the author are drawn upon the concept of subjectivity, here usedwithin a dialogical, dialectic and complex framework. Subjectivity is defined by processes of meaning and subjective sensesthat configure the subject and the personality, and the different social dimensions in which the subject acts. The concept ofneed is understood in a recurring relationship with emotions, i.e, both of them are simultaneously the "cause"and the "result",along their reciprocal relationship. Motive is here defined as a subjective configuration which is constituted by, and at the sametime constitutes, the personality.La reflexión presentada por el autor tiene como punto de partida el concepto de subjetividad, el cual retoma desde una perpectiva compleja, dialógica y dialéctica, en la cual la subjetividad se define por los procesos de significación y sentido subjetivo que caracterizan al sujeto, la personalidad y las diferentes instancias sociales en las cuales el sujeto actua. La necesidad se presenta en un relación recursiva con las emociones, en la cual ambas aparecen, en momentos diferentes, como causas y productos de las relaciones que establecen entre si. El motivo es definido como configuracion constituyente de la personalidad y, simultáneamente, como sistema constituído por ella.A reflexão apresentada pelo autor tem como ponto de partida o conceito de subjetividade, o qual retoma desdeuma perspectiva complexa, dialógica e dialética, na qual a subjetividade se define pelos processos de significação e sentidosubjetivo que caraterizam ao sujeito, a personalidade e as diferentes instâncias sociais nas quais o sujeito atua. A necessidadese apresenta em um relacionamento recorrente com as emoções, no qual ambas aparecem em momentos diferentes comocausas e produtos das relações que estabelecem entre si. O motivo é definido como configuração constituinte da personalidadee, simultaneamente, como sistema por ela constituído
Bioinspired design of triboceramics: Learning from the anisotropic microfracture response of dental enamel under sliding contact
[EN] In the quest for novel ceramics for tribological applications via bioinspired design, the differences in the fracture modes that arise upon scratching relevant locations of ceramic-like tooth enamel are investigated. It is found that fracture initiates from weak rod-sheath interfaces at relatively low loads, independent of the sliding direction. However, the geometry and propagation of the cracks depends on the orientation of the interfaces relative to the maximum tensile stress: scratching along the occlusal surface propagates approximately sinusoidal cracks, parallel to the sliding direction, while scratching along the cross-section produces straight cracks that propagate normal (scratch parallel to occlusal surface) or parallel (scratch perpendicular to occlusal surface) to the sliding direction. The formation of cracks is hindered in scratching near the enamel-dentine junction. Implications for the microstructural design of triboceramics (bulks and coatings) with improved durability are discussed.The authors wish to thank Dr Florencio Monje Gil for kindly providing tooth specimens from his clinic (CICOM, Centro de Implantologia Cirugia Oral y Maxilofacial, Badajoz, Spain). This study was supported by Junta de Extremadura, Spain, and FEDER/ERDF funds (grants IB16139 and GR18149), and the Spanish Ministry of Science and Innovation (grant PID2019-105377RB-I00). E. P.-C. gratefully acknowledges support from the Spanish Ministry of Economy and Competitiveness (MINECO) under grant FJCI-2015-27228.Sanchez-Gonzalez, E.; Rodriguez-Rojas, F.; Pinilla-Cienfuegos, E.; Borrero-Lopez, O.; Ortiz, AL.; Guiberteau, F. (2020). Bioinspired design of triboceramics: Learning from the anisotropic microfracture response of dental enamel under sliding contact. Ceramics International. 46(18):27983-27989. https://doi.org/10.1016/j.ceramint.2020.07.2922798327989461
Landslide dams in the Central Andes of Argentina: showing the need of revising the established landslide dam classification
The Andean cordillera of Argentina is more than 3500 km long and 50 to 550 km wide and characterized by steep relief contrasts throughout. Except for a few valleys, most of this region is scarcely populated. Hence geologic mapping was mainly carried out on a scale (1:250000), which is often too small to map out various Quaternary units and therefore to highlight relations of landslide deposits with lakes or lake deposits. However, in the last years various studies have been carried out, concentrating on large landslides and their relations with valley impoundments (GONZÁLEZ DIAZ & MON, 1996; HERMANNS & STRECKER, 1999; TRAUTH & STRECKER, 1999; GONZÁLEZ DÍAZ et alii, 2000; HERMANNS et alii, 2000; TRAUTH et alii, 2000; FAUQUE et alii, 2000; FAUQUÉ & TCHILINGUIRIAN, 2002; TRAUTH et alii, 2003; HERMANNS et alii, 2003; HERMANNS et alii, 2005; FAUQUE et alii, 2005; PENNA et alii, 2005; GONZÁLEZ DÍAZ et alii, 2005). Before that, most attention was given to the catastrophic rock avalanche dam failure in the Barrancas valley causing the 1914 Río Colorado flood (GROEBER, 1916; GONZÁLEZ DÍAZ et alii, 2001; SCHUSTER et alii, 2002; HERMANNS et alii, 2004a). In this paper we will focus on two regions: one in the NW Argentine (24° - 27.5° S) and one in northern Patagonia (36° – 38° S). In both regions the authors have carried out systematic studies related to landslides with volumes in excess of 106 m3. These landslides formed at least 16 and 48 landslide dams in the two regions, respectively (Figure 1). In the following, due to the briefness of this paper, only peculiarities of the various cases will be described which will help to better understand large landslide dams in other regions as well. For the complete data set of both study areas we refer to the comprehensive paper, which will be published within the related NATO Science Series book. Likewise, we omit a setting description of the regions and refer here to the papers cited above.Fil: Hermanns, R. L.. Canadian Geological Survey; CanadáFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Gonzalez Diaz, E. F.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Fauque, L.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentin
Drug repurposing: tolfenamic acid inactivates PrbP, a transcriptional accessory protein in liberibacter asiaticus
CLIBASIA_01510, PrbP, is a predicted RNA polymerase binding protein in Liberibacter asiaticus. PrbP was found to regulate expression of a small subset of ribosomal genes through interactions with the β-subunit of the RNA polymerase and a short, specific sequence on the promoter region. Molecular screening assays were performed to identify small molecules that interact with PrbP in vitro. Chemical hits were analyzed for therapeutic efficacy against L. asiaticus via an infected leaf assay, where the transcriptional activity of L. asiaticus was found to decrease significantly after exposure to tolfenamic acid. Similarly, tolfenamic acid was found to inhibit L. asiaticus infection in highly symptomatic citrus seedlings. Our results indicate that PrbP is an important transcriptional regulator for survival of L. asiaticus in planta, and the chemicals identified by molecular screening assays could be used as a therapeutic treatment for huanglongbing disease.Fil: Gardner, Christopher L.. University of Florida; Estados UnidosFil: Pagliai, Fernando A.. University of Florida; Estados UnidosFil: Pan, Lei. University of Florida; Estados UnidosFil: Bojilova, Lora. University of Florida; Estados UnidosFil: Torino, Maria Ines. University of Florida; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Lorca, Graciela L.. University of Florida; Estados UnidosFil: Gonzalez, Claudio F.. University of Florida; Estados Unido
A hybrid double-dot in silicon
We report electrical measurements of a single arsenic dopant atom in the
tunnel-barrier of a silicon SET. As well as performing electrical
characterization of the individual dopant, we study series electrical transport
through the dopant and SET. We measure the triple points of this hybrid double
dot, using simulations to support our results, and show that we can tune the
electrostatic coupling between the two sub-systems.Comment: 11 pages, 6 figure
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