Acceleration of Amphibian Forelimb Regeneration By Polypeptide Growth Factors

Growth factors are potentially important modulators of epimorphic regeneration. This study examined effects of intraperitoneal administration of selected growth factors on limb regeneration of adult newts, Notophthalmus viridescens. These agents stimulated regeneration, producing overlapping but nonidentical effects. Fibroblast growth factor-2 (FGF-2) and insulin-like growth factor I (IGF-I) stimulated bud emergence (8.3 ± 0.6 and 8.3 ± 0.7 days, respectively, vs 11.4 ± 1.1 days for controls). Progression to the cone stage was enhanced by both FGF-2 and transforming growth factor beta 5 ( TGF-~ 5) ; 14.6 ± 0.5 and 15.4 ± 0.4 days with FGF-2 and TGF-~5 , respectively, vs 16.5 ± 0.5 days in controls. Insulin accelerated attainment of the palette stage, 17.0 ± 0.7 days vs 19.0 ± 0.4 days for controls. No treatments affected attaining the digital stage; means between 22.4 and 23.4 days. Histological analysis revealed changes consistent with gross observations. In addition, regenerates from newts treated with FGF-2, TGF-~5. and insulin displayed signs of greater (or earlier) histogenesis than did control animals. These results are consistent with the notion that FGF-2, TGF-~5. and possibly lGF-I stimulate proliferation of blastema cells and that insulin, FGF-2, and TGF-~5 promote differentiation and histogenesis during forelimb regeneration. In conclusion, these results demonstrate that several polypeptide growth factors positively affect the progress of forelimb regeneration, that different growth factors influence the same or similar events of epimorphic regeneration, and that diverse growth factors have nonidentical effects on regeneration

Apoptosis of Rat Myoblasts Is Induced In Vitro by Late, but Not Early, Wound Fluids

Interstitial fluids from late wound repair environments are not regeneration permissive as judged by their inability to promote either proliferation or differentiation of myoblasts in vitro. This irwestigation considered whether apoptosis (induced death) was an alternative fate for myoblasts exposed to these interstitial fluids. Myoblast fate was assessed by cell counts, tritiated thymidine release, and propidium iodide staining. Fluids from early wounds increased mean cell counts and induced little thymidine release or propidium iodide labeling. In contrast, fluids from late wounds reduced cell counts and induced both thymidine release and propidium iodide labeling. These data suggest that interstitial fluids from late wounds might trigger apoptosis. It is presently unclear how death is induced in these environments. Further study is required to ascertain whether these effects represent an impediment to skeletal muscle regeneration only or if they reflect a previously unidentified role for late wound fluids in postinjury resolution

1-d gravity in infinite point distributions

The dynamics of infinite, asymptotically uniform, distributions of self-gravitating particles in one spatial dimension provides a simple toy model for the analogous three dimensional problem. We focus here on a limitation of such models as treated so far in the literature: the force, as it has been specified, is well defined in infinite point distributions only if there is a centre of symmetry (i.e. the definition requires explicitly the breaking of statistical translational invariance). The problem arises because naive background subtraction (due to expansion, or by "Jeans' swindle" for the static case), applied as in three dimensions, leaves an unregulated contribution to the force due to surface mass fluctuations. Following a discussion by Kiessling, we show that the problem may be resolved by defining the force in infinite point distributions as the limit of an exponentially screened pair interaction. We show that this prescription gives a well defined (finite) force acting on particles in a class of perturbed infinite lattices, which are the point processes relevant to cosmological N-body simulations. For identical particles the dynamics of the simplest toy model is equivalent to that of an infinite set of points with inverted harmonic oscillator potentials which bounce elastically when they collide. We discuss previous results in the literature, and present new results for the specific case of this simplest (static) model starting from "shuffled lattice" initial conditions. These show qualitative properties (notably its "self-similarity") of the evolution very similar to those in the analogous simulations in three dimensions, which in turn resemble those in the expanding universe.Comment: 20 pages, 8 figures, small changes (section II shortened, added discussion in section IV), matches final version to appear in PR

Wound Repair

Following injury, a series of events is initiated that includes global and local reactions. Global reactions, such as inflammatory and immunological responses as well as adjustments in neural and endocrine status, are directed at marshaling the organism\u27s resources for dealing with changes in its integrity and the potential threat of infection or other complications. Injury entails cell and tissue damage and often a physical breach in the barrier against the outside world (e.g., skin). Local reactions are exemplified by immediate hemostatic (e.g., blood clotting) events followed by changes in local cellular composition created by the inflammatory infiltrate and adjustments in resident cell function. These are accompanied by local metabolic adjustments. These events are directed at restoring local integrity and establishing a relevant steady-state. The typical events of wound repair are extensively documented and well characterized. In recent years, research has explored regulation of wound repair at the cellular level and has sought alternative modes for correcting tissue damage that yield more efficient restoration of preinjury conditions (e.g., regeneration). Since repair typically leads to replacement of damaged tissues with connective tissue, reduction in function invariably accompanies wound healing. Where tissue damage is slight, this causes little or no problem for the individual. However, when tissue damage is great, as for example when a finger or limb is lost, the compromise of wound repair carries a noticeable price (both in actual costs and in quality of life for the affected individual)

Quantum hypercomputation based on the dynamical algebra su(1,1)

An adaptation of Kieu's hypercomputational quantum algorithm (KHQA) is presented. The method that was used was to replace the Weyl-Heisenberg algebra by other dynamical algebra of low dimension that admits infinite-dimensional irreducible representations with naturally defined generalized coherent states. We have selected the Lie algebra $\mathfrak{su}(1,1)$, due to that this algebra posses the necessary characteristics for to realize the hypercomputation and also due to that such algebra has been identified as the dynamical algebra associated to many relatively simple quantum systems. In addition to an algebraic adaptation of KHQA over the algebra $\mathfrak{su}(1,1)$, we presented an adaptations of KHQA over some concrete physical referents: the infinite square well, the infinite cylindrical well, the perturbed infinite cylindrical well, the P{\"o}sch-Teller potentials, the Holstein-Primakoff system, and the Laguerre oscillator. We conclude that it is possible to have many physical systems within condensed matter and quantum optics on which it is possible to consider an implementation of KHQA.Comment: 25 pages, 1 figure, conclusions rewritten, typing and language errors corrected and latex format changed minor changes elsewhere and

Multiple-hour-ahead forecast of the Dst index using a combination of Long Short-Term Memory neural network and Gaussian process

In this study, we present a method that combines a Long Short-Term Memory (LSTM) recurrent neural network with a Gaussian process (GP) model to provide up to 6-hr-ahead probabilistic forecasts of the Dst geomagnetic index. The proposed approach brings together the sequence modeling capabilities of a recurrent neural network with the error bars and confidence bounds provided by a GP. Our model is trained using the hourly OMNI and Global Positioning System (GPS) databases, both of which are publicly available. We first develop a LSTM network to get a single-point prediction of Dst. This model yields great accuracy in forecasting the Dst index from 1 to 6 hr ahead, with a correlation coefficient always higher than 0.873 and a root-mean-square error lower than 9.86. However, even if global metrics show excellent performance, it remains poor in predicting intense storms (Dst < −250 nT) 6 hr in advance. To improve it and to obtain probabilistic forecasts, we combine the LSTM model obtained with a GP and evaluate the hybrid predictor using the receiver operating characteristic curve and the reliability diagram. We conclude that this hybrid methodology provides improvements in the forecast of geomagnetic storms, from 1 to 6 hr ahead

Earlinet validation of CATS L2 product

The Cloud-Aerosol Transport System (CATS) onboard the International Space Station (ISS), is a lidar system providing vertically resolved aerosol and cloud profiles since February 2015. In this study, the CATS aerosol product is validated against the aerosol profiles provided by the European Aerosol Research Lidar Network (EARLINET). This validation activity is based on collocated CATS-EARLINET measurements and the comparison of the particle backscatter coefficient at 1064nm.Peer ReviewedPostprint (published version

Flux-based ozone risk assessment for a plant injury index (pii) in three european cool-temperate deciduous tree species

This study investigated visible foliar ozone (O3) injury in three deciduous tree species with different growth patterns (indeterminate, Alnus glutinosa (L.) Gaertn.; intermediate, Sorbus aucuparia L.; and determinate, Vaccinium myrtillus L.) from May to August 2018. Ozone effects on the timing of injury onset and a plant injury index (PII) were investigated using two O3 indices, i.e., AOT40 (accumulative O3 exposure over 40 ppb during daylight hours) and PODY (phytotoxic O3 dose above a flux threshold of Y nmol m&minus;2 s&minus;1). A new parameterization for PODY estimation was developed for each species. Measurements were carried out in an O3 free-air controlled exposure (FACE) experiment with three levels of O3 treatment (ambient, AA; 1.5 &times; AA; and 2.0 &times; AA). Injury onset was found in May at 2.0 &times; AA in all three species and the timing of the onset was determined by the amount of stomatal O3 uptake. It required 4.0 mmol m&minus;2 POD0 and 5.5 to 9.0 ppm&middot;h AOT40. As a result, A. glutinosa with high stomatal conductance (gs) showed the earliest emergence of O3 visible injury among the three species. After the onset, O3 visible injury expanded to the plant level as confirmed by increased PII values. In A. glutinosa with indeterminate growth pattern, a new leaf formation alleviated the expansion of O3 visible injury at the plant level. V. myrtillus showed a dramatic increase of PII from June to July due to higher sensitivity to O3 in its flowering and fruiting stage. Ozone impacts on PII were better explained by the flux-based index, PODY, as compared with the exposure-based index, AOT40. The critical levels (CLs) corresponding to PII = 5 were 8.1 mmol m&minus;2 POD7 in A. glutinosa, 22 mmol m&minus;2 POD0 in S. aucuparia, and 5.8 mmol m&minus;2 POD1 in V. myrtillus. The results highlight that the CLs for PII are species-specific. Establishing species-specific O3 flux-effect relationships should be key for a quantitative O3 risk assessment

Terras Pretas de Índio of the Caquetá-Japurá River (Colombian Amazonia)

Amazonian dark earths, or terra preta, constitute archaeological evidence of ancient human settlements. They are distributed throughout the Amazon basin, especially concentrated along its major rivers. In the region of La Pedrera, on the Caquetá (Japurá) River in Colombian Amazonia, archaeological studies have demonstrated the presence of these fertile soils extending over areas of 3 to 5 hectares with an anthropic horizon that varies from 70 cm to 1.2 m in depth. Associated with the sites are faunal remains from fish, turtles, and small rodents, as well as a high density of ceramic fragments and botanical remains, including phytoliths, charcoal, and seeds, the latter two dated to between 6500 and 1300 yBP. Archaeobotanical data (seeds and phytoliths) suggest intensive use of palms by pre-Columbian peoples. High sample densities were observed for the following species: canangucha/burití (Mauritia flexuosa), asaí/açaí (Euterpe precatoria), seje/batauá (Oenocarpus bataua), milpesito/bacabinha (O. bacaba), chambira/tucuma (Astrocaryum chambira), palma real/inajai (Attalea maripa), puy/caraná (Lepidocaryum tenue), and species of the genus Bactris. Archaeological remains of manioc (Manihot esculenta), maize (Zea mays), and squash (Cucurbita sp.) were also identified, along with the following fruit species: Annona sp., ice cream bean/guama (Inga edulis), cocoa/cacau (Theobroma cacao), cupuaçu (Theobroma grandiflorum) and pineapple (Ananas comosus). Various herbaceous taxa, indicators of disturbed areas, were also identified, along with elements used in the elaboration of ceramics (Licania sp.). These preliminary results suggest that the Amazonian dark earths of La Pedrera were used for agricultural production and human habitation. We also note that their location, near rapids, is strategic for fishing and land management