502 research outputs found
Neuropsychological constraints to human data production on a global scale
Which are the factors underlying human information production on a global
level? In order to gain an insight into this question we study a corpus of
252-633 Million publicly available data files on the Internet corresponding to
an overall storage volume of 284-675 Terabytes. Analyzing the file size
distribution for several distinct data types we find indications that the
neuropsychological capacity of the human brain to process and record
information may constitute the dominant limiting factor for the overall growth
of globally stored information, with real-world economic constraints having
only a negligible influence. This supposition draws support from the
observation that the files size distributions follow a power law for data
without a time component, like images, and a log-normal distribution for
multimedia files, for which time is a defining qualia.Comment: to be published in: European Physical Journal
Depolarizing metrics for plant samples imaging
Optical methods, as fluorescence microscopy or hyperspectral imaging, are commonly used for plants visualization and characterization. Another powerful collection of optical techniques is the so-called polarimetry, widely used to enhance image contrast in multiple applications. In the botanical applications framework, in spite of some works have already highlighted the depolarizing print that plant structures left on input polarized beams, the potential of polarimetric methods has not been properly exploited. In fact, among the few works dealing with polarization and plants, most of them study light scattered by plants using the Degree of Polarization (DoP) indicator. Other more powerful depolarization metrics are nowadays neglected. In this context, we highlight the potential of different depolarization metrics obtained using the Mueller matrix (MM) measurement: the Depolarization Index and the Indices of Polarimetric Purity. We perform a qualitative and quantitative comparison between DoP- and MM-based images by studying a particular plant, the Hedera maroccana. We show how Mueller-based metrics are generally more suitable in terms of contrast than DoP-based measurements. The potential of polarimetric measurements in the study of plants is highlighted in this work, suggesting they can be applied to the characterization of plants, plant taxonomy, water stress in plants, and other botanical studies
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Applying GIS characterizing and modeling contaminant transport in surface water at Los Alamos National Laboratory
During World War II, Los Alamos, New Mexico was chosen as the site for the secret development of the first atomic bomb. The remote location in the southwestern United States was ideal for such a project. After the war, research activities continued at the Los Alamos installation, focusing on new nuclear weapons models as well as greater effectiveness and reliability of existing weapons. Due to the emphasis on nuclear and non-nuclear weapons development as well as associated nuclear research, a large inventory of radionuclides and heavy metals have been tested, expended, and disposed of in the local environment, a high plateau of tuffaceous volcanic rocks incised by deep canyons in a semi-arid climate. In recent years an intensive evaluation of the environmental, impact of weapons testing at Los Alamos and elsewhere has been undertaken. GIS system utilization and image processing of past and current data has been an important part of this evaluation. Important problems can be more easily displayed and understood using this methodology. The main objective in this paper is to illustrate how transport of depleted uranium and associated heavy metals (copper in this case) used in dynamic testing of weapons components at open air firing sites can be evaluated and visualized. In our studies, surface water has been found to be the predominant transport mechanism. We have sampled soils, sediments, fallout, runoff water and snowmelt over a number of years in order to understand contaminant transport on- and offsite. Statistical analyses of these data have assisted in our characterization of issues such as contaminant variability, spatially and temporally, as well as in development of transport rates
Variational Principle underlying Scale Invariant Social Systems
MaxEnt's variational principle, in conjunction with Shannon's logarithmic
information measure, yields only exponential functional forms in
straightforward fashion. In this communication we show how to overcome this
limitation via the incorporation, into the variational process, of suitable
dynamical information. As a consequence, we are able to formulate a somewhat
generalized Shannonian Maximum Entropy approach which provides a unifying
"thermodynamic-like" explanation for the scale-invariant phenomena observed in
social contexts, as city-population distributions. We confirm the MaxEnt
predictions by means of numerical experiments with random walkers, and compare
them with some empirical data
Inclusion of Hermetia Illucens larvae or prepupae in an experimental extruded feed: process optimisation and impact on in vitro digestibility
This study investigated the effect of extrusion on digestibility of different blends containing Hermetia illucens (HI) larvae or prepupae. Five blends of HI larvae or prepupae and wheat flour, in a ratio of 25:75, with or without sunflower oil addition, have been formulated as follows: prepupae\u2009+\u2009wheat (no oil); prepupae\u2009+\u2009wheat (low oil); prepupae\u2009+\u2009wheat (medium oil); prepupae\u2009+\u2009wheat (high oil); larvae\u2009+\u2009wheat (no oil). Ether extract (EE) content in different blend was 31.5, 38.9, 46.3, 53.7 and 46.27\u2009g\u2009kg 121 on wet basis (wb), respectively. Blends were homogeneous for moisture (238.9\u2009g\u2009kg 121) and crude protein (112.6\u2009g\u2009kg 121 wb). Feed blends were extruded by a co-rotating, conical twin-screw mini extruder and net torque value (NTV) was recorded as indicator of extrudability. The best performing blend was furtherly tested at four barrel temperatures (60, 70, 80 and 90\u2009\ub0C). In vitro organic matter digestibility (OMD) and in vitro crude protein digestibility (CPD) were measured to evaluate the effect of extrusion process on nutritional value. Increasing the blend EE content up to 53.74\u2009g kg 121 wb, NTV was reduced by four times (<100 Ncm) compared to 31.5 and 38.9\u2009g kg 121 wb EE blends. The best performing mixture was larvae\u2009+\u2009wheat (no oil). Extrusion process increased OMD but not CPD compared to unextruded control, while different extrusion temperature did not affect OMD nor CPD. Concluding, extrusion can contribute to increase OMD in insect containing feed blends. EE content in the blends is a key variable that should be defined in the process
Sustained safety and performance of the second-generation drug-eluting absorbable metal scaffold in patients with de novo coronary lesions: 12-month clinical results and angiographic findings of the BIOSOLVE-II first-in-man trial.
Metal absorbable scaffolds constitute a conceptually attractive alternative to polymeric scaffolds. Promising 6-month outcomes of a second-generation drug-eluting absorbable metal scaffold (DREAMS 2G), consisting of an absorbable magnesium scaffold backbone, have been reported. We assessed the 12-month safety and performance of this novel device.
The prospective, international, multi-centre, first-in-man BIOSOLVE-II trial enrolled 123 patients with up to two de novo lesions with a reference diameter between 2.2 and 3.7 mm. All patients were scheduled for angiographic follow-up at 6 months, and-if subjects consented-at 12 months. Dual antiplatelet therapy was recommended for 6 months. Quantitative coronary angiography (QCA) parameters remained stable from 6 to 12 months [paired data of 42 patients: in-segment late lumen loss 0.20 ± 0.21 mm vs. 0.25 ± 0.22 mm, P = 0.117, Δ 0.05 ± 0.21 mm (95% CI: -0.01;0.12); in-scaffold late lumen loss 0.37 ± 0.25 mm vs. 0.39 ± 0.27 mm, P = 0.446, Δ 0.03 ± 0.22 (95% CI: -0.04;0.10), respectively]. Intravascular ultrasound and optical coherence tomography findings corroborated the QCA results. Target lesion failure occurred in four patients (3.4%), consisting of one death of unknown cause, one target-vessel myocardial infarction, and two clinically driven target lesion revascularization. No additional event occurred beyond the 6-month follow-up. During the entire follow-up of 12 months, none of the patients experienced a definite or probable scaffold thrombosis.
The novel drug-eluting metal absorbable scaffold DREAMS 2G showed a continuous favourable safety profile up to 12 months and stable angiographic parameters between 6 and 12 months.
NCT01960504
Ancient DNA of guinea pigs (Cavia spp.) indicates a probable new center of domestication and pathways of global distribution
Guinea pigs (Cavia spp.) have a long association with humans. From as early as 10,000 years ago they were a wild food source. Later, domesticated Cavia porcellus were dispersed well beyond their native range through pre-Columbian exchange networks and, more recently, widely across the globe. Here we present 46 complete mitogenomes of archaeological guinea pigs from sites in Peru, Bolivia, Colombia, the Caribbean, Belgium and the United States to elucidate their evolutionary history, origins and paths of dispersal. Our results indicate an independent centre of domestication of Cavia in the eastern Colombian Highlands. We identify a Peruvian origin for the initial introduction of domesticated guinea pigs (Cavia porcellus) beyond South America into the Caribbean. We also demonstrate that Peru was the probable source of the earliest known guinea pigs transported, as part of the exotic pet trade, to both Europe and the southeastern United States. Finally, we identify a modern reintroduction of guinea pigs to Puerto Rico, where local inhabitants use them for food. This research demonstrates that the natural and cultural history of guinea pigs is more complex than previously known and has implications for other studies regarding regional to global-scale studies of mammal domestication, translocation, and distribution.Fil: Lord, E.. Stockholms Universitet; Suecia. University of Otago; Nueva ZelandaFil: Collins, C.. University of Otago; Nueva ZelandaFil: deFrance, S.. University of Florida; Estados UnidosFil: LeFebvre, M. J.. University of Florida; Estados UnidosFil: Pigière, F.. Universidad de Dublin; IrlandaFil: Eeckhout, P.. Université Libre de Bruxelles; BélgicaFil: Erauw, C.. Université Libre de Bruxelles; BélgicaFil: Fitzpatrick, S. M.. State University of Oregon; Estados UnidosFil: Healy, P. F.. Trent University; CanadáFil: Martínez Polanco, M. F.. Muséum National d'Histoire Naturelle; Francia. Universitat Rovira I Virgili; España. Institut Català de Paleoecologia Humana i Evolució Social; EspañaFil: Garcia, J. L.. Stetson University; Estados UnidosFil: Ramos Roca, E.. Universidad de los Andes. Facultad de Ciencias Sociales. Departamento de Antropología; ColombiaFil: Delgado Burbano, Miguel Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Área Antropológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. School of Life Sciences and Human Phenome Institute Fudan University; ChinaFil: Sánchez Urriago, A.. Instituto Colombiano de Antropología e Historia; ColombiaFil: Peña Léon, G. A.. Universidad Nacional de Colombia; ColombiaFil: Toyne, J. M.. University of Florida; Estados UnidosFil: Dahlstedt, A.. Arizona State University; Estados UnidosFil: Moore, K. M.. State University of Pennsylvania; Estados UnidosFil: Laguer Diaz, C.. University of Florida; Estados UnidosFil: Zori, C.. Baylor University; Estados UnidosFil: Matisoo-Smith, E.. University of Otago; Nueva Zeland
Statistical Analyses Support Power Law Distributions Found in Neuronal Avalanches
The size distribution of neuronal avalanches in cortical networks has been reported to follow a power law distribution with exponent close to −1.5, which is a reflection of long-range spatial correlations in spontaneous neuronal activity. However, identifying power law scaling in empirical data can be difficult and sometimes controversial. In the present study, we tested the power law hypothesis for neuronal avalanches by using more stringent statistical analyses. In particular, we performed the following steps: (i) analysis of finite-size scaling to identify scale-free dynamics in neuronal avalanches, (ii) model parameter estimation to determine the specific exponent of the power law, and (iii) comparison of the power law to alternative model distributions. Consistent with critical state dynamics, avalanche size distributions exhibited robust scaling behavior in which the maximum avalanche size was limited only by the spatial extent of sampling (“finite size” effect). This scale-free dynamics suggests the power law as a model for the distribution of avalanche sizes. Using both the Kolmogorov-Smirnov statistic and a maximum likelihood approach, we found the slope to be close to −1.5, which is in line with previous reports. Finally, the power law model for neuronal avalanches was compared to the exponential and to various heavy-tail distributions based on the Kolmogorov-Smirnov distance and by using a log-likelihood ratio test. Both the power law distribution without and with exponential cut-off provided significantly better fits to the cluster size distributions in neuronal avalanches than the exponential, the lognormal and the gamma distribution. In summary, our findings strongly support the power law scaling in neuronal avalanches, providing further evidence for critical state dynamics in superficial layers of cortex
De visserskaai te Oostende (prov. West-Vlaanderen): archeologie van een in de 17de eeuw zwaar geteisterde stad
The Institute for the Archaeological Heritage of the Flemish Community (IAP) has, in close collaboration with the town of Ostend, carried out archaeological excavations during the construction works of the car park below the Visserskaai at Ostend from September 1998 till February 1999. This archaeological work mainly produced information on the eastern ramparts of Ostend and their evolution from the 16th century onwards together with information on the material culture of the inhabitants of Ostend during this same period. The town of Ostend had no defences until late in the 16th century as initial construction work for the defences only started in 1572 when the town came into northern hands. In the beginning of the 17th century Ostend managed to withstand successfully, with its newly built ramparts, for three years an overwhelming Spanish army siege. This was only possible thanks to the fact that the Spaniards never managed to seal of Ostend completely from the sea. As a result, victuals and soldiers arrived continuously at Ostend during the siege. It was only after the arrival of Spinola in the besieging camp, at the end of 1603, that Ostend was gradually forced to surrender. At the bottom of the excavated car park trench, some 4 m below the actual street level, wooden structures of the earthen ramparts were preserved (figs. 4-5). The presence of these con- firms historical data about the use of wood to strengthen the earthen ramparts. The excavations however documented mainly features from 2 bastions, the Peckels bastion and the Spanish bastion (fig. 2-3). Human burials and a gunpowder-magazine (figs. 7, 8, 10, 12) were uncovered in the Peckels bastion and human burials and an open-air rainwater reservoir were detected in the Spanish bastion. The human burials are studied elsewhere in this volume together with other post-medieval burials from Ostend recently discovered outside regular cemeteries. Archaeological material found in connection with the gunpowder-magazine in the Peckelf bastion dates from the 2nd half of the 16th /1st half of the 17th century (figs. 6,9,13-15) and suggests that the construction of this gunpowder-magazine? has to be situated somewhere in the middle of the 17th century, in other words in the period when the town defences of Ostend were adapted to new standards after the above- mentioned siege. A typical object related to the siege is a funnel-shaped gunpowder-flask in a copper-alloy (fig. 6). The inner wall of the gunpowder-magazine was erected on a framework of horizontal wooden beams, which were themselves resting on vertically placed and sharpened beams, mainly in oak (fig. 8). A dendrochronological analysis of the vertically placed beams produced a terminus post quem, which is far too early to be of any help in the discussion on the gunpowder-magazine. The technical differences between the inner and outer wall of the gunpowder-magazine suggest at least 2 phases for this building. The above-mentioned ceramics consist of redwares, Rhenish stone- wares a.o. Raeren, maiolicas, Weser slipwares, olive jars from Seville and some whitewares with green or yellow glaze. The archaeological material from the open- air rainwater reservoir in the Spanish bastion dates from the 2nd half of the 17th/1st half of the 19th century but mainly from the 18th century (figs. 16-32). The collection of ceramics from this context is largely dominated by tablewares. Among these stonewares are nearly missing and replaced by faience, china and industrial white- wares (pearl and cream wares). Maiolica has been nearly completely replaced by faience. Maiolicas remain in fact only important as wall-tiles. The collection contains some olive jars from Seville, a bowl from Dèsvres and a few products from Beauvais. The collection of china mainly consists of cups and small dishes in blue and white china. The china has been brought to Ostend in great quantities in the 18th century, first by the Ostend Company and later by mariners from Ostend in Foreign Service, mainly as ship's ballast. Besides ceramics this context also produced several finds in leather, glass, stone and metal. The leather finds mainly consist of shoes. The glass collection is largely dominated by cylindrical and globular bottles of which one was still intact including its cork (fig. 26: 1). Metal is represented by 22 cast iron cannon balls (fig. 28) and by a standard measure for bottles from an unidentified town inspector of measures and weights of Ostend with GS initials (fig. 27: 8). Small quantities of animal remains were found dispersed over many contexts within the site's stratigraphy. Only three of them are meaningful: a deposit found under the floor of the gunpowder-magazine (table 1: context A), an assemblage excavated in leveling layers within the Peckels bastion (table 1: context B), and material found in the water reservoir in the Spanish bastion (table 1: context C). All connections consisted of larger material; sieved samples did not yield meaningful numbers of smaller animal remains. Context A dates from the second half of the 16th to the first half of the 17th century and consists of consumption refuse: marine molluscs, marine fish bones, bird bone and the remains of cattle, sheep and pig. Context B is contemporaneous to context A and also represents consumption refuse with a similar composition. Remarkable are only a series of vertebrae of a large specimen of ling, a fish that must have been caught in northern waters, and a number of skeletal elements of a gurnard species. Context C has a younger date (second half of the 17th century to the first half of the 19th century) and has a mixed origin in terms of the taphonomy of the animal remains. Not only consumption refuse is present but also parts of the skeletons of at least four dogs and a horse. It is possible that all three contexts represent secondary refuse; in any case their provenance remains unknown. The material certainly has limited value for the interpretation of former consumption patterns. A feature of special interest is the presence of a few cowrie shells. Several aspects of the material culture reflect the maritime character of the town: the presence of several imports such as olive jars from Seville and specific objects as a token in lead (fig. 13: 16) probably used by skippers for the payment of fees and/or tolls. The presence of an important percentage of china and of some cowrie shells is probably related to the activities of the Ostend Company in the l8th century. The pottery discovered from both contexts (2nd half 16th century/ 1 st half 17th century and 2nd half 17th century/ 1st half 19th century) follows the general trends described for post-medieval Flanders
Adduct formation identification between phenyl glycidyl ether and 2'-deoxyadenosine and thymidine by chromatography, mass spectrometry and nuclear magnetic resonance spectroscopy
Thymidine 2'-deoxyadenosine were reacted with phenyl glycidyl ether in order to study the formation of the corresponding 2'-deoxynucleoside adducts. Separation methods were elaborated using either reversed-phase high-performance liquid chromatography with photodiode-array detection, or centrifugal circular thin-layer chromatography. The adducts were isolated on a preparative scale and were fully characterized by UV spectroscopy, desorption chemical ionization and fast atom bombardment mass spectrometry and 270- and 360-MHz 1H NMR spectrometry. For thymidine the main adduct was characterized as N-3-(2-hydroxy-3-phenoxypropyl)thymidine. With 2'-deoxyadenosine, predominantly N-l-(2-hydroxy-3-phenoxypropyl)-2'-deoxyadenosine was formed. With longer reaction times, the formation of a minor amount of dialkylated 2'-deoxyadenosine was observed. These nucleoside adducts will be used as marker compounds for studies of DNA adduct formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28807/1/0000641.pd
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