En Inchola, caserío situado en la umbría de la Sierra de Carrascoy, se levantan los restos de una estructura defensiva medieval, llamada Torre de Inchola, y los de una antigua conducción hidráulica ...conocida como Caño del Barracón. En ambas edificaciones se desarrolla un variado repertorio de signos grabados sobre sus muros, entre los que predominan los que reproducen la forma de herradura. En este trabajo se describe la tipología de los grabados, proponiendo posibles líneas de interpretación histórica y una probable datación de los mismos en el contexto de los inicios de la Edad Moderna en el Reino de Murcia.
rock engraving made by Neanderthals in Gibraltar Rodríguez-Vidal, Joaquín; d'Errico, Francesco; Pacheco, Francisco Giles ...
Proceedings of the National Academy of Sciences - PNAS,
09/2014, Volume:
111, Issue:
37
Journal Article
Peer reviewed
Open access
Significance The production of purposely made painted or engraved designs on cave walls is recognized as a major cognitive step in human evolution, considered exclusive to modern humans. Here we ...present the first known example of an abstract pattern engraved by Neanderthals, from Gorham’s Cave in Gibraltar. It consists of a deeply impressed cross-hatching carved into the bedrock of the cave older than 39 cal kyr. The engraving was made before the accumulation of Mousterian layer IV. Most of the lines composing the design were made by repeatedly and carefully passing a pointed lithic tool into the grooves, excluding the possibility of an unintentional or utilitarian origin. This discovery demonstrates the Neanderthals’ capacity for abstract thought and expression.
Focimeters, especially manual versions, are the most used ophthalmic devices for dioptric power measurement in optometric clinical care. In the particular case of progressive addition lenses (PALs), ...they are used to determine far/near vision correction powers, but the user/clinician needs to know at which part of the PAL the measurement must be taken. For this reason, PALs have permanent engravings acting as reference marks to define the far/near vision areas for every PAL design. However, for several reasons these engravings are often difficult to localize and identify, making an accurate dioptric power determination difficult. In this Letter, we present an adaptation of the Gabor holographic principle to a manual focimeter and describe the methodology for the correct localization, visualization, and marking process of the reference engravings in PALs. Experimental results considering different types of PALs are included and the main limitations of the technique are also discussed.
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•A simple and easy fabrication method for laser engraved porous graphene (LEPG).•Bi-functional H2O2 and glucose electrochemical sensor were designed based on GOD/Pt-LEPG.•The obtained ...flexible sensor exhibited a high sensitivity by decorating Pt NPs and immobilizing glucose oxidase.•A simple and effective way to fabricate flexible electronic devices was explored.
Polyimide-laser-engraved porous graphene (LEPG) are hopeful electrode modification materials for flexible electrochemical sensing based on its high-efficiency preparation and low cost. Herein, a flexible, multi-patterned, and miniaturized electrode was fabricated via a simple and novel direct laser engraving. 3D LEPG with porous network structure can selective decorated with Pt nanoparticles (Pt NPs) by in situ electrochemical depositions (Pt-LEPG) as sensitively H2O2 sensors with a wide range of linear (0.01–29 nM) and high sensitivity (575.75 μA mM−1 cm-2). Subsequently, a glucose biosensor was successfully constructed through immobilized glucose oxidases (GOD) onto Pt-LEPG electrode. New-designed GOD/Pt-LEPG glucose sensor exhibited a noteworthy lower limit of detection (0.3 μM, S/N = 3) and high sensitivity (241.82 μA mM-1 cm-2), as much a wide-range of linear (0.01–31.5 mM) at near-neutral pH conditions, enabling detect glucose in real human serum specimens with satisfactory results. Predictably, these outstanding performance sensors have great potential in terms of flexible and wearable electronics.
Micro-nano scale surface modification of Ti-6Al-4V was investigated through the fascinated modern fiber engraving laser method. The process was performed at a high laser speed of 2000mm/s, under ...different laser frequencies (20–160kHz) and groove distances (0.5–50μm).
Topographic evaluations such as Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FE-SEM) were used to identify the quality and regularity of patterns. The proliferation of human osteoblast-like osteosarcoma cells (MG63) was analyzed by MTT assay for up to 72h. Also, the plate counting method was used to quantify the viability potential of the modified surface against Escherichia coli bacteria.
The cellular viability of the sample modified at the laser frequency of 20kHz and grooving distance of 50μm increased up to 35 and 10% compared to the non-treated and control samples, respectively. In the case of the surface modification at lower grooving distances range between 0.5–50μm, the maximum laser frequency (160kHz) applied leads to lower pulse’s energies and less bacterial adhesion. Otherwise, at groove distances more than 50μm, the minimum laser frequency (20kHz) applied reduces the laser pulse overlaps, increases the cell adhesion and antibacterial properties.
Surface modification by the fiber engraving laser process significantly enhances the cell adhesion on the surface. As a result of such roughness and cell adhesion enhancement, the surface toxicity feature diminished, and its antibacterial properties improved.
Nanovoids within a polyamide layer play an important role in the separation performance of thin-film composite (TFC) reverse osmosis (RO) membranes. To form more extensive nanovoids for enhanced ...performance, one commonly used method is to incorporate sacrificial nanofillers in the polyamide layer during the exothermic interfacial polymerization (IP) reaction, followed by some post-etching processes. However, these post-treatments could harm the membrane integrity, thereby leading to reduced selectivity. In this study, we applied
self-etchable sacrificial nanofillers by taking advantage of the strong acid and heat generated in IP. CaCO
nanoparticles (nCaCO
) were used as the model nanofillers, which can be
etched by reacting with H
to leave void nanostructures behind. This reaction can further degas CO
nanobubbles assisted by heat in IP to form more nanovoids in the polyamide layer. These nanovoids can facilitate water transport by enlarging the effective surface filtration area of the polyamide and reducing hydraulic resistance to significantly enhance water permeance. The correlations between the nanovoid properties and membrane performance were systematically analyzed. We further demonstrate that the nCaCO
-tailored membrane can improve membrane antifouling propensity and rejections to boron and As(III) compared with the control. This study investigated a novel strategy of applying self-etchable gas precursors to engrave the polyamide layer for enhanced membrane performance, which provides new insights into the design and synthesis of TFC membranes.
How did human symbolic behavior evolve? Dating up to about 100,000 y ago, the engraved ochre and ostrich eggshell fragments from the South African Blombos Cave and Diepkloof Rock Shelter provide a ...unique window into presumed early symbolic traditions of Homo sapiens and how they evolved over a period of more than 30,000 y. Using the engravings as stimuli, we report five experiments which suggest that the engravings evolved adaptively, becoming better-suited for human perception and cognition. More specifically, they became more salient, memorable, reproducible, and expressive of style and human intent. However, they did not become more discriminable over time between or within the two archeological sites. Our observations provide support for an account of the Blombos and Diepkloof engravings as decorations and as socially transmitted cultural traditions. By contrast, there was no clear indication that they served as denotational symbolic signs. Our findings have broad implications for our understanding of early symbolic communication and cognition in H. sapiens.
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